Merge pull request #144 from squat/fix_graph_newlines

pkg/mesh/graph.go: fix format

.github/workflows/ci.yml

@@ -0,0 +1,141 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  schedule:
+  - cron:  '0 0 * * *'
+  workflow_dispatch:
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Build
+      run: make
+
+  linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Build kg and kgctl for all Linux Architectures
+      run: make all-build
+
+  darwin:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Build kgctl for Darwin
+      run: make OS=darwin
+
+  windows:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Build kgctl for Windows
+      run: make OS=windows
+
+  unit:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Run Unit Tests
+      run: make unit
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Lint Code
+      run: make lint
+
+  container:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Enable Experimental Docker CLI
+      run: |
+        echo $'{\n  "experimental": true\n}' | sudo tee /etc/docker/daemon.json
+        mkdir -p ~/.docker
+        echo $'{\n  "experimental": "enabled"\n}' | sudo tee ~/.docker/config.json
+        sudo service docker restart
+        docker version -f '{{.Client.Experimental}}'
+        docker version -f '{{.Server.Experimental}}'
+        docker buildx version
+    - name: Container
+      run: make container
+
+  push:
+    if: github.event_name != 'pull_request'
+    needs:
+    - build
+    - linux
+    - darwin
+    - windows
+    - unit
+    - lint
+    - container
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Enable Experimental Docker CLI
+      run: |
+        echo $'{\n  "experimental": true\n}' | sudo tee /etc/docker/daemon.json
+        mkdir -p ~/.docker
+        echo $'{\n  "experimental": "enabled"\n}' | sudo tee ~/.docker/config.json
+        sudo service docker restart
+        docker version -f '{{.Client.Experimental}}'
+        docker version -f '{{.Server.Experimental}}'
+        docker buildx version
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@master
+      with:
+        platforms: all
+    - name: Login to DockerHub
+      if: github.event_name != 'pull_request'
+      uses: docker/login-action@v1
+      with:
+        username: ${{ secrets.DOCKER_USERNAME }}
+        password: ${{ secrets.DOCKER_PASSWORD }}
+    - name: Build and push
+      if: github.event_name != 'pull_request'
+      run: make manifest
+    - name: Build and push latest
+      if: github.event_name != 'pull_request' && github.ref == 'refs/heads/main'
+      run: make manifest-latest

.github/workflows/release.yaml

@@ -0,0 +1,21 @@
+on:
+  release:
+    types: [created]
+name: Handle Release
+jobs:
+  linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.15.7
+    - name: Make Directory with kgctl Binaries to Be Released
+      run: make release
+    - name: Publish Release
+      uses: skx/github-action-publish-binaries@master
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        args: 'bin/release/kgctl-*'

.gitignore

@@ -3,3 +3,4 @@
 .manifest*
 .push*
 bin/
+tmp/

.travis.yml

@@ -1,31 +0,0 @@
-sudo: required
-
-dist: xenial
-
-language: go
-
-services:
-  - docker
-
-go:
-  - 1.14.2
-
-env:
-  - GO111MODULE=on DOCKER_CLI_EXPERIMENTAL=enabled
-
-before_install:
-  - sudo apt-get update && sudo apt-get -y install jq
-
-install: true
-
-script:
-  - make
-  - make clean
-  - make unit
-  - make lint
-  - make container
-
-after_success:
-  - docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD"
-  - docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
-  - make manifest && make manifest-latest

Dockerfile

@@ -11,5 +11,5 @@ LABEL maintainer="squat <lserven@gmail.com>"
 RUN echo -e "https://alpine.global.ssl.fastly.net/alpine/v3.12/main\nhttps://alpine.global.ssl.fastly.net/alpine/v3.12/community" > /etc/apk/repositories && \
     apk add --no-cache ipset iptables ip6tables wireguard-tools
 COPY --from=cni bridge host-local loopback portmap /opt/cni/bin/
-COPY bin/$GOARCH/kg /opt/bin/
+COPY bin/linux/$GOARCH/kg /opt/bin/
 ENTRYPOINT ["/opt/bin/kg"]

MAINTAINERS.md

@@ -0,0 +1,6 @@
+# Core Maintainers of This Repository
+
+| Name               | GitHub                                         |
+|--------------------|------------------------------------------------|
+| Lucas Servén Marín | [@squat](https://github.com/squat)             |
+| Leon Löchner       | [@leonnicolas](https://github.com/leonnicolas) |

Makefile

@@ -1,10 +1,18 @@
 export GO111MODULE=on
-.PHONY: push container clean container-name container-latest push-latest fmt lint test unit vendor header generate client deepcopy informer lister openapi manifest manfest-latest manifest-annotate manifest manfest-latest manifest-annotate
+.PHONY: push container clean container-name container-latest push-latest fmt lint test unit vendor header generate client deepcopy informer lister openapi manifest manfest-latest manifest-annotate manifest manfest-latest manifest-annotate release
 
-ARCH ?= amd64
+OS ?= $(shell go env GOOS)
+ARCH ?= $(shell go env GOARCH)
+ALL_OS := linux darwin windows
 ALL_ARCH := amd64 arm arm64
 DOCKER_ARCH := "amd64" "arm v7" "arm64 v8"
-BINS := $(addprefix bin/$(ARCH)/,kg kgctl)
+ifeq ($(OS),linux)
+    BINS := bin/$(OS)/$(ARCH)/kg bin/$(OS)/$(ARCH)/kgctl
+else
+    BINS := bin/$(OS)/$(ARCH)/kgctl
+endif
+RELEASE_BINS := $(addprefix bin/release/kgctl-, $(addprefix linux-, $(ALL_ARCH)) darwin-amd64 windows-amd64)
+CLIENT_BINS := $(addsuffix /kgctl, $(addprefix bin/, $(addprefix linux/, $(ALL_ARCH)) darwin/amd64 windows/amd64))
 PROJECT := kilo
 PKG := github.com/squat/$(PROJECT)
 REGISTRY ?= index.docker.io
@@ -31,14 +39,15 @@ INFORMER_GEN_BINARY := bin/informer-gen
 LISTER_GEN_BINARY := bin/lister-gen
 OPENAPI_GEN_BINARY := bin/openapi-gen
 GOLINT_BINARY := bin/golint
+EMBEDMD_BINARY := bin/embedmd
 
-BUILD_IMAGE ?= golang:1.14.2-alpine
+BUILD_IMAGE ?= golang:1.15.7-alpine
 BASE_IMAGE ?= alpine:3.12
 
 build: $(BINS)
 
 build-%:
-	@$(MAKE) --no-print-directory ARCH=$* build
+	@$(MAKE) --no-print-directory OS=$(word 1,$(subst -, ,$*)) ARCH=$(word 2,$(subst -, ,$*)) build
 
 container-latest-%:
 	@$(MAKE) --no-print-directory ARCH=$* container-latest
@@ -52,7 +61,7 @@ push-latest-%:
 push-%:
 	@$(MAKE) --no-print-directory ARCH=$* push
 
-all-build: $(addprefix build-, $(ALL_ARCH))
+all-build: $(addprefix build-$(OS)-, $(ALL_ARCH))
 
 all-container: $(addprefix container-, $(ALL_ARCH))
 
@@ -132,7 +141,7 @@ pkg/k8s/apis/kilo/v1alpha1/openapi_generated.go: pkg/k8s/apis/kilo/v1alpha1/type
 	go fmt $@
 
 $(BINS): $(SRC) go.mod
-	@mkdir -p bin/$(ARCH)
+	@mkdir -p bin/$(word 2,$(subst /, ,$@))/$(word 3,$(subst /, ,$@))
 	@echo "building: $@"
 	@docker run --rm \
 	    -u $$(id -u):$$(id -g) \
@@ -140,8 +149,8 @@ $(BINS): $(SRC) go.mod
 	    -w /$(PROJECT) \
 	    $(BUILD_IMAGE) \
 	    /bin/sh -c " \
-	        GOARCH=$(ARCH) \
-	        GOOS=linux \
+	        GOARCH=$(word 3,$(subst /, ,$@)) \
+	        GOOS=$(word 2,$(subst /, ,$@)) \
 	        GOCACHE=/$(PROJECT)/.cache \
 		CGO_ENABLED=0 \
 		go build -mod=vendor -o $@ \
@@ -190,7 +199,7 @@ header: .header
 	FILES=; \
 	for f in $(GO_FILES); do \
 		for i in 0 1 2 3 4 5; do \
-			FILE=$$(tail -n +$$i $$f | head -n $$HEADER_LEN | sed "s/[0-9]\{4\}/YEAR/"); \
+			FILE=$$(t=$$(mktemp) && tail -n +$$i $$f > $$t && head -n $$HEADER_LEN $$t | sed "s/[0-9]\{4\}/YEAR/"); \
 			[ "$$FILE" = "$$HEADER" ] && continue 2; \
 		done; \
 		FILES="$$FILES$$f "; \
@@ -200,6 +209,13 @@ header: .header
 		exit 1; \
 	fi
 
+tmp/help.txt: bin/$(OS)/$(ARCH)/kg
+	mkdir -p tmp
+	bin//$(OS)/$(ARCH)/kg --help 2>&1 | head -n -1 > $@
+
+docs/kg.md: $(EMBEDMD_BINARY) tmp/help.txt
+	$(EMBEDMD_BINARY) -w $@
+
 website/docs/README.md: README.md
 	rm -rf website/static/img/graphs
 	find docs  -type f -name '*.md' | xargs -I{} sh -c 'cat $(@D)/$$(basename {} .md) > website/{}'
@@ -216,7 +232,7 @@ website/build/index.html: website/docs/README.md
 	yarn --cwd website build
 
 container: .container-$(ARCH)-$(VERSION) container-name
-.container-$(ARCH)-$(VERSION): $(BINS) Dockerfile
+.container-$(ARCH)-$(VERSION): bin/linux/$(ARCH)/kg Dockerfile
 	@i=0; for a in $(ALL_ARCH); do [ "$$a" = $(ARCH) ] && break; i=$$((i+1)); done; \
 	ia=""; iv=""; \
 	j=0; for a in $(DOCKER_ARCH); do \
@@ -281,6 +297,12 @@ push-latest: container-latest
 push-name:
 	@echo "pushed: $(IMAGE):$(ARCH)-$(VERSION)"
 
+release: $(RELEASE_BINS)
+$(RELEASE_BINS):
+	@make OS=$(word 2,$(subst -, ,$(@F))) ARCH=$(word 3,$(subst -, ,$(@F)))
+	mkdir -p $(@D)
+	cp bin/$(word 2,$(subst -, ,$(@F)))/$(word 3,$(subst -, ,$(@F)))/kgctl $@
+
 clean: container-clean bin-clean
 	rm -rf .cache
 
@@ -311,3 +333,6 @@ $(OPENAPI_GEN_BINARY):
 
 $(GOLINT_BINARY):
 	go build -mod=vendor -o $@ golang.org/x/lint/golint
+
+$(EMBEDMD_BINARY):
+	go build -mod=vendor -o $@ github.com/campoy/embedmd

README.md

@@ -4,7 +4,7 @@
 
 Kilo is a multi-cloud network overlay built on WireGuard and designed for Kubernetes.
 
-[![Build Status](https://travis-ci.org/squat/kilo.svg?branch=master)](https://travis-ci.org/squat/kilo)
+[![Build Status](https://github.com/squat/kilo/workflows/CI/badge.svg)](https://github.com/squat/kilo/actions?query=workflow%3ACI)
 [![Go Report Card](https://goreportcard.com/badge/github.com/squat/kilo)](https://goreportcard.com/report/github.com/squat/kilo)
 
 ## Overview
@@ -14,6 +14,8 @@ By allowing pools of nodes in different locations to communicate securely, Kilo
 Kilo's design allows clients to VPN to a cluster in order to securely access services running on the cluster.
 In addition to creating multi-cloud clusters, Kilo enables the creation of multi-cluster services, i.e. services that span across different Kubernetes clusters.
 
+An introductory video about Kilo from KubeCon EU 2019 can be found on [youtube](https://www.youtube.com/watch?v=iPz_DAOOCKA).
+
 ## How it works
 
 Kilo uses [WireGuard](https://www.wireguard.com/), a performant and secure VPN, to create a mesh between the different nodes in a cluster.
@@ -26,15 +28,14 @@ This means that if a cluster uses, for example, Flannel for networking, Kilo can
 
 Kilo can be installed on any Kubernetes cluster either pre- or post-bring-up.
 
-### Step 1: install WireGuard
+### Step 1: get WireGuard
 
-Kilo requires the WireGuard kernel module on all nodes in the cluster.
-For most Linux distributions, this can be installed using the system package manager.
-For Container Linux, WireGuard can be easily installed using a DaemonSet:
+Kilo requires the WireGuard kernel module to be loaded on all nodes in the cluster.
+Starting at Linux 5.6, the kernel includes WireGuard in-tree; Linux distributions with older kernels will need to install WireGuard.
+For most Linux distributions, this can be done using the system package manager.
+[See the WireGuard website for up-to-date instructions for installing WireGuard](https://www.wireguard.com/install/).
 
-```shell
-kubectl apply -f https://raw.githubusercontent.com/squat/modulus/master/wireguard/daemonset.yaml
-```
+Clusters with nodes on which the WireGuard kernel module cannot be installed can use Kilo by leveraging a [userspace WireGuard implementation](./docs/userspace-wireguard.md).
 
 ### Step 2: open WireGuard port
 
@@ -68,25 +69,25 @@ Kilo can be installed by deploying a DaemonSet to the cluster.
 To run Kilo on kubeadm:
 
 ```shell
-kubectl apply -f https://raw.githubusercontent.com/squat/kilo/master/manifests/kilo-kubeadm.yaml
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-kubeadm.yaml
 ```
 
 To run Kilo on bootkube:
 
 ```shell
-kubectl apply -f https://raw.githubusercontent.com/squat/kilo/master/manifests/kilo-bootkube.yaml
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-bootkube.yaml
 ```
 
 To run Kilo on Typhoon:
 
 ```shell
-kubectl apply -f https://raw.githubusercontent.com/squat/kilo/master/manifests/kilo-typhoon.yaml
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-typhoon.yaml
 ```
 
 To run Kilo on k3s:
 
 ```shell
-kubectl apply -f https://raw.githubusercontent.com/squat/kilo/master/manifests/kilo-k3s.yaml
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-k3s.yaml
 ```
 
 ## Add-on Mode
@@ -98,10 +99,10 @@ Kilo currently supports running on top of Flannel.
 For example, to run Kilo on a Typhoon cluster running Flannel:
 
 ```shell
-kubectl apply -f https://raw.githubusercontent.com/squat/kilo/master/manifests/kilo-typhoon-flannel.yaml
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-typhoon-flannel.yaml
 ```
 
-[See the manifests directory for more examples](https://github.com/squat/kilo/tree/master/manifests).
+[See the manifests directory for more examples](https://github.com/squat/kilo/tree/main/manifests).
 
 ## VPN
 

cmd/kg/main.go

@@ -16,7 +16,6 @@ package main
 
 import (
 	"errors"
-	"flag"
 	"fmt"
 	"net"
 	"net/http"
@@ -24,12 +23,14 @@ import (
 	"os/signal"
 	"strings"
 	"syscall"
+	"time"
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/oklog/run"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	flag "github.com/spf13/pflag"
 	apiextensions "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/clientcmd"
@@ -80,6 +81,7 @@ var (
 func Main() error {
 	backend := flag.String("backend", k8s.Backend, fmt.Sprintf("The backend for the mesh. Possible values: %s", availableBackends))
 	cleanUpIface := flag.Bool("clean-up-interface", false, "Should Kilo delete its interface when it shuts down?")
+	createIface := flag.Bool("create-interface", true, "Should kilo create an interface on startup?")
 	cni := flag.Bool("cni", true, "Should Kilo manage the node's CNI configuration?")
 	cniPath := flag.String("cni-path", mesh.DefaultCNIPath, "Path to CNI config.")
 	compatibility := flag.String("compatibility", "", fmt.Sprintf("Should Kilo run in compatibility mode? Possible values: %s", availableCompatibilities))
@@ -92,9 +94,11 @@ func Main() error {
 	local := flag.Bool("local", true, "Should Kilo manage routes within a location?")
 	logLevel := flag.String("log-level", logLevelInfo, fmt.Sprintf("Log level to use. Possible values: %s", availableLogLevels))
 	master := flag.String("master", "", "The address of the Kubernetes API server (overrides any value in kubeconfig).")
+	topologyLabel := flag.String("topology-label", k8s.RegionLabelKey, "Kubernetes node label used to group nodes into logical locations.")
 	var port uint
 	flag.UintVar(&port, "port", mesh.DefaultKiloPort, "The port over which WireGuard peers should communicate.")
 	subnet := flag.String("subnet", mesh.DefaultKiloSubnet.String(), "CIDR from which to allocate addresses for WireGuard interfaces.")
+	resyncPeriod := flag.Duration("resync-period", 30*time.Second, "How often should the Kilo controllers reconcile?")
 	printVersion := flag.Bool("version", false, "Print version and exit")
 	flag.Parse()
 
@@ -171,12 +175,12 @@ func Main() error {
 		c := kubernetes.NewForConfigOrDie(config)
 		kc := kiloclient.NewForConfigOrDie(config)
 		ec := apiextensions.NewForConfigOrDie(config)
-		b = k8s.New(c, kc, ec)
+		b = k8s.New(c, kc, ec, *topologyLabel)
 	default:
 		return fmt.Errorf("backend %v unknown; possible values are: %s", *backend, availableBackends)
 	}
 
-	m, err := mesh.New(b, enc, gr, *hostname, uint32(port), s, *local, *cni, *cniPath, *iface, *cleanUpIface, log.With(logger, "component", "kilo"))
+	m, err := mesh.New(b, enc, gr, *hostname, uint32(port), s, *local, *cni, *cniPath, *iface, *cleanUpIface, *createIface, *resyncPeriod, log.With(logger, "component", "kilo"))
 	if err != nil {
 		return fmt.Errorf("failed to create Kilo mesh: %v", err)
 	}

cmd/kgctl/main.go

@@ -60,9 +60,10 @@ var (
 		granularity mesh.Granularity
 		port        uint32
 	}
-	backend     string
-	granularity string
-	kubeconfig  string
+	backend       string
+	granularity   string
+	kubeconfig    string
+	topologyLabel string
 )
 
 func runRoot(_ *cobra.Command, _ []string) error {
@@ -83,7 +84,7 @@ func runRoot(_ *cobra.Command, _ []string) error {
 		c := kubernetes.NewForConfigOrDie(config)
 		kc := kiloclient.NewForConfigOrDie(config)
 		ec := apiextensions.NewForConfigOrDie(config)
-		opts.backend = k8s.New(c, kc, ec)
+		opts.backend = k8s.New(c, kc, ec, topologyLabel)
 	default:
 		return fmt.Errorf("backend %v unknown; posible values are: %s", backend, availableBackends)
 	}
@@ -110,6 +111,7 @@ func main() {
 	cmd.PersistentFlags().StringVar(&granularity, "mesh-granularity", string(mesh.LogicalGranularity), fmt.Sprintf("The granularity of the network mesh to create. Possible values: %s", availableGranularities))
 	cmd.PersistentFlags().StringVar(&kubeconfig, "kubeconfig", os.Getenv("KUBECONFIG"), "Path to kubeconfig.")
 	cmd.PersistentFlags().Uint32Var(&opts.port, "port", mesh.DefaultKiloPort, "The WireGuard port over which the nodes communicate.")
+	cmd.PersistentFlags().StringVar(&topologyLabel, "topology-label", k8s.RegionLabelKey, "Kubernetes node label used to group nodes into logical locations.")
 
 	for _, subCmd := range []*cobra.Command{
 		graph(),

cmd/kgctl/showconf.go

@@ -289,9 +289,16 @@ func translatePeer(peer *wireguard.Peer) *v1alpha1.Peer {
 		aips = append(aips, aip.String())
 	}
 	var endpoint *v1alpha1.PeerEndpoint
-	if peer.Endpoint != nil && peer.Endpoint.Port > 0 && peer.Endpoint.IP != nil {
+	if peer.Endpoint != nil && peer.Endpoint.Port > 0 && (peer.Endpoint.IP != nil || peer.Endpoint.DNS != "") {
+		var ip string
+		if peer.Endpoint.IP != nil {
+			ip = peer.Endpoint.IP.String()
+		}
 		endpoint = &v1alpha1.PeerEndpoint{
-			IP:   peer.Endpoint.IP.String(),
+			DNSOrIP: v1alpha1.DNSOrIP{
+				DNS: peer.Endpoint.DNS,
+				IP:  ip,
+			},
 			Port: peer.Endpoint.Port,
 		}
 	}

docs/annotations.md

@@ -5,7 +5,7 @@ The following annotations can be added to any Kubernetes Node object to configur
 |Name|type|examples|
 |----|----|-------|
 |[kilo.squat.ai/force-endpoint](#force-endpoint)|host:port|`55.55.55.55:51820`, `example.com:1337`|
-|[kilo.squat.ai/force-internal-ip](#force-internal-ip)|CIDR|`55.55.55.55/32`|
+|[kilo.squat.ai/force-internal-ip](#force-internal-ip)|CIDR|`55.55.55.55/32`, `"-"`,`""`|
 |[kilo.squat.ai/leader](#leader)|string|`""`, `true`|
 |[kilo.squat.ai/location](#location)|string|`gcp-east`, `lab`|
 |[kilo.squat.ai/persistent-keepalive](#persistent-keepalive)|uint|`10`|
@@ -25,6 +25,7 @@ Kilo routes packets destined for nodes inside the same logical location using th
 The Kilo agent running on each node will use heuristics to automatically detect a private IP address for the node; however, in some circumstances it may be necessary to explicitly configure the IP address, for example:
  * _multiple private IP addresses_: if a node has multiple private IPs but one is preferred, then the preferred IP address should be specified;
  * _IPv6_: if a node has both private IPv4 and IPv6 addresses and the Kilo network should operate over IPv6, then the IPv6 address should be specified.
+ * _disable private IP with "-" or ""_: a node has a private and public address, but the private address ought to be ignored.
 
 ### leader
 By default, Kilo creates a network mesh at the data-center granularity.

docs/kg.md

@@ -0,0 +1,40 @@
+# kg
+
+`kg` is the Kilo agent that runs on every Kubernetes node in a Kilo mesh.
+It performs several key functions, including:
+* adding the node to the Kilo mesh;
+* installing CNI configuration on the node;
+* configuring the WireGuard network interface; and
+* maintaining routing table entries and iptables rules.
+
+`kg` is typically installed on all nodes of a Kubernetes cluster using a DaemonSet.
+Example manifests can be found [in the manifests directory](https://github.com/squat/kilo/tree/main/manifests).
+
+## Usage
+
+The behavior of `kg` can be configured using the command line flags listed below.
+
+[embedmd]:# (../tmp/help.txt)
+```txt
+Usage of bin//linux/amd64/kg:
+      --backend string            The backend for the mesh. Possible values: kubernetes (default "kubernetes")
+      --clean-up-interface        Should Kilo delete its interface when it shuts down?
+      --cni                       Should Kilo manage the node's CNI configuration? (default true)
+      --cni-path string           Path to CNI config. (default "/etc/cni/net.d/10-kilo.conflist")
+      --compatibility string      Should Kilo run in compatibility mode? Possible values: flannel
+      --create-interface          Should kilo create an interface on startup? (default true)
+      --encapsulate string        When should Kilo encapsulate packets within a location? Possible values: never, crosssubnet, always (default "always")
+      --hostname string           Hostname of the node on which this process is running.
+      --interface string          Name of the Kilo interface to use; if it does not exist, it will be created. (default "kilo0")
+      --kubeconfig string         Path to kubeconfig.
+      --listen string             The address at which to listen for health and metrics. (default ":1107")
+      --local                     Should Kilo manage routes within a location? (default true)
+      --log-level string          Log level to use. Possible values: all, debug, info, warn, error, none (default "info")
+      --master string             The address of the Kubernetes API server (overrides any value in kubeconfig).
+      --mesh-granularity string   The granularity of the network mesh to create. Possible values: location, full (default "location")
+      --port uint                 The port over which WireGuard peers should communicate. (default 51820)
+      --resync-period duration    How often should the Kilo controllers reconcile? (default 30s)
+      --subnet string             CIDR from which to allocate addresses for WireGuard interfaces. (default "10.4.0.0/16")
+      --topology-label string     Kubernetes node label used to group nodes into logical locations. (default "topology.kubernetes.io/region")
+      --version                   Print version and exit
+```

docs/kgctl.md

@@ -8,7 +8,7 @@ This tool can be used to understand a mesh's topology, get the WireGuard configu
 
 Installing `kgctl` currently requires building the binary from source.
 *Note*: the [Go toolchain must be installed](https://golang.org/doc/install) in order to build the binary.
-To build and install `kgctl`, simply run:
+To build and install `kgctl`, run:
 
 ```shell
 go install github.com/squat/kilo/cmd/kgctl

docs/multi-cluster-services.md

@@ -5,7 +5,7 @@ This enables clusters to provide services to other clusters over a secure connec
 For example, a cluster on AWS with access to GPUs could run a machine learning service that could be consumed by workloads running in a another location, e.g. an on-prem cluster without GPUs.
 Unlike services exposed via Ingresses or NodePort Services, multi-cluster services can remain private and internal to the clusters.
 
-*Note*: in order for connected clusters to be fully routable, the allowed IPs that they declare must be non-overlapping, i.e. the Kilo, pod, and service CIDRs.
+> **Note**: in order for connected clusters to be fully routable, the allowed IPs that they declare must be non-overlapping, i.e. the Kilo, pod, and service CIDRs.
 
 ## Getting Started
 

docs/network-policies.md

@@ -10,7 +10,7 @@ Support for [Kubernetes network policies](https://kubernetes.io/docs/concepts/se
 The following command adds network policy support by deploying kube-router to work alongside Kilo:
 
 ```shell
-kubectl apply -f kubectl apply -f https://raw.githubusercontent.com/squat/kilo/master/manifests/kube-router.yaml
+kubectl apply -f kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kube-router.yaml
 ```
 
 ## Examples

docs/topology.md

@@ -11,9 +11,10 @@ This allows the encrypted network to serve several purposes, for example:
 
 By default, Kilo creates a mesh between the different logical locations in the cluster, e.g. data-centers, cloud providers, etc.
 Kilo will try to infer the location of the node using the [topology.kubernetes.io/region](https://kubernetes.io/docs/reference/kubernetes-api/labels-annotations-taints/#topologykubernetesioregion) node label.
+Additionally, Kilo supports using a custom topology label by setting the command line flag `--topology-label=<label>`. 
 If this label is not set, then the [kilo.squat.ai/location](./annotations.md#location) node annotation can be used.
 
-For example, in order to join nodes in Google Cloud and AWS into a single cluster, an administrator could use the following snippet could to annotate all nodes with `GCP` in the name:
+For example, in order to join nodes in Google Cloud and AWS into a single cluster, an administrator could use the following snippet to annotate all nodes with `GCP` in the name:
 
 ```shell
 for node in $(kubectl get nodes | grep -i gcp | awk '{print $1}'); do kubectl annotate node $node kilo.squat.ai/location="gcp"; done

docs/userspace-wireguard.md

@@ -0,0 +1,34 @@
+# Userspace WireGuard
+
+It is possible to use a userspace implementation of WireGuard with Kilo.
+This can make sense in cases where
+
+* not all nodes in a cluster have WireGuard installed; or
+* nodes are effectively immutable and kernel modules cannot be installed.
+
+## Homogeneous Clusters
+
+In a homogeneous cluster where no node has the WireGuard kernel module, a userspace WireGuard implementation can be made available by deploying a DaemonSet.
+This DaemonSet creates a WireGuard interface that Kilo will manage.
+In order to avoid race conditions, `kg` needs to be passed the `--create-interface=false` flag. 
+
+An example configuration for a k3s cluster with [boringtun](https://github.com/cloudflare/boringtun) can be applied with:
+
+```shell
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-k3s-userspace.yaml
+```
+
+__Note:__ even if some nodes have the WireGuard kernel module, this configuration will cause all nodes to use the userspace implementation of WireGuard.
+
+## Heterogeneous Clusters
+
+In a heterogeneous cluster where some nodes are missing the WireGuard kernel module, a userspace WireGuard implementation can be provided only to the nodes that need it while enabling the other nodes to leverage WireGuard via the kernel module.
+An example of such a configuration for a k3s cluster can by applied with:
+
+```shell
+kubectl apply -f https://raw.githubusercontent.com/squat/kilo/main/manifests/kilo-k3s-userspace-heterogeneous.yaml
+```
+
+This configuration will deploy [nkml](https://github.com/leonnicolas/nkml) as a DaemonSet to label all nodes according to the presence of the WireGuard kernel module.
+It will also create two different DaemonSets with Kilo: `kilo` without userspace WireGuard and `kilo-userspace` with boringtun as a sidecar.
+__Note:__ because Kilo is dependant on nkml, nkml must be run on the host network before CNI is available and requires a kubeconfig in order to access the Kubernetes API.

docs/vpn.md

@@ -3,6 +3,7 @@
 Kilo enables peers outside of a Kubernetes cluster to connect to the created WireGuard network.
 This enables several use cases, for example:
 * giving cluster applications secure access to external services, e.g. services behind a corporate VPN;
+* improving the development flow of applications by running them locally and connecting them to the cluster;
 * allowing external services to access the cluster; and
 * enabling developers and support to securely debug cluster resources.
 
@@ -74,7 +75,7 @@ From any node or Pod on the cluster, one can now ping the peer:
 ping 10.5.0.1
 ```
 
-If the peer exposes a layer 4 service, for example an HTTP service, then one could also make requests against that endpoint from the cluster:
+If the peer exposes a layer 4 service, for example an HTTP server listening on TCP port 80, then one could also make requests against that endpoint from the cluster:
 
 ```shell
 curl http://10.5.0.1

go.mod

@@ -1,11 +1,12 @@
 module github.com/squat/kilo
 
-go 1.14
+go 1.15
 
 require (
 	github.com/PuerkitoBio/purell v1.1.1 // indirect
 	github.com/ant31/crd-validation v0.0.0-20180801212718-38f6a293f140
 	github.com/awalterschulze/gographviz v0.0.0-20181013152038-b2885df04310
+	github.com/campoy/embedmd v1.0.0
 	github.com/containernetworking/cni v0.6.0
 	github.com/containernetworking/plugins v0.6.0
 	github.com/coreos/go-iptables v0.4.0
@@ -37,6 +38,7 @@ require (
 	github.com/onsi/gomega v1.5.0 // indirect
 	github.com/prometheus/client_golang v0.9.2
 	github.com/spf13/cobra v0.0.4-0.20190321000552-67fc4837d267
+	github.com/spf13/pflag v1.0.3
 	github.com/stretchr/testify v1.3.0 // indirect
 	github.com/vishvananda/netlink v1.0.0
 	github.com/vishvananda/netns v0.0.0-20180720170159-13995c7128cc // indirect

go.sum

@@ -1,6 +1,5 @@
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/PuerkitoBio/purell v1.1.0 h1:rmGxhojJlM0tuKtfdvliR84CFHljx9ag64t2xmVkjK4=
 github.com/PuerkitoBio/purell v1.1.0/go.mod h1:c11w/QuzBsJSee3cPx9rAFu61PvFxuPbtSwDGJws/X0=
 github.com/PuerkitoBio/purell v1.1.1 h1:WEQqlqaGbrPkxLJWfBwQmfEAE1Z7ONdDLqrN38tNFfI=
 github.com/PuerkitoBio/purell v1.1.1/go.mod h1:c11w/QuzBsJSee3cPx9rAFu61PvFxuPbtSwDGJws/X0=
@@ -13,6 +12,8 @@ github.com/awalterschulze/gographviz v0.0.0-20181013152038-b2885df04310 h1:t+qxR
 github.com/awalterschulze/gographviz v0.0.0-20181013152038-b2885df04310/go.mod h1:GEV5wmg4YquNw7v1kkyoX9etIk8yVmXj+AkDHuuETHs=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 h1:xJ4a3vCFaGF/jqvzLMYoU8P317H5OQ+Via4RmuPwCS0=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
+github.com/campoy/embedmd v1.0.0 h1:V4kI2qTJJLf4J29RzI/MAt2c3Bl4dQSYPuflzwFH2hY=
+github.com/campoy/embedmd v1.0.0/go.mod h1:oxyr9RCiSXg0M3VJ3ks0UGfp98BpSSGr0kpiX3MzVl8=
 github.com/containernetworking/cni v0.6.0 h1:FXICGBZNMtdHlW65trpoHviHctQD3seWhRRcqp2hMOU=
 github.com/containernetworking/cni v0.6.0/go.mod h1:LGwApLUm2FpoOfxTDEeq8T9ipbpZ61X79hmU3w8FmsY=
 github.com/containernetworking/plugins v0.6.0 h1:bqPT7yYisnWs+FrtgY5/qLEB9QZ/6z11wMNCwSdzZm0=
@@ -38,17 +39,14 @@ github.com/go-kit/kit v0.8.0 h1:Wz+5lgoB0kkuqLEc6NVmwRknTKP6dTGbSqvhZtBI/j0=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-logfmt/logfmt v0.4.0 h1:MP4Eh7ZCb31lleYCFuwm0oe4/YGak+5l1vA2NOE80nA=
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
-github.com/go-openapi/jsonpointer v0.17.0 h1:nH6xp8XdXHx8dqveo0ZuJBluCO2qGrPbDNZ0dwoRHP0=
 github.com/go-openapi/jsonpointer v0.17.0/go.mod h1:cOnomiV+CVVwFLk0A/MExoFMjwdsUdVpsRhURCKh+3M=
 github.com/go-openapi/jsonpointer v0.19.0 h1:FTUMcX77w5rQkClIzDtTxvn6Bsa894CcrzNj2MMfeg8=
 github.com/go-openapi/jsonpointer v0.19.0/go.mod h1:cOnomiV+CVVwFLk0A/MExoFMjwdsUdVpsRhURCKh+3M=
-github.com/go-openapi/jsonreference v0.17.0 h1:yJW3HCkTHg7NOA+gZ83IPHzUSnUzGXhGmsdiCcMexbA=
 github.com/go-openapi/jsonreference v0.17.0/go.mod h1:g4xxGn04lDIRh0GJb5QlpE3HfopLOL6uZrK/VgnsK9I=
 github.com/go-openapi/jsonreference v0.19.0 h1:BqWKpV1dFd+AuiKlgtddwVIFQsuMpxfBDBHGfM2yNpk=
 github.com/go-openapi/jsonreference v0.19.0/go.mod h1:g4xxGn04lDIRh0GJb5QlpE3HfopLOL6uZrK/VgnsK9I=
 github.com/go-openapi/spec v0.19.0 h1:A4SZ6IWh3lnjH0rG0Z5lkxazMGBECtrZcbyYQi+64k4=
 github.com/go-openapi/spec v0.19.0/go.mod h1:XkF/MOi14NmjsfZ8VtAKf8pIlbZzyoTvZsdfssdxcBI=
-github.com/go-openapi/swag v0.17.0 h1:iqrgMg7Q7SvtbWLlltPrkMs0UBJI6oTSs79JFRUi880=
 github.com/go-openapi/swag v0.17.0/go.mod h1:AByQ+nYG6gQg71GINrmuDXCPWdL640yX49/kXLo40Tg=
 github.com/go-openapi/swag v0.19.0 h1:Kg7Wl7LkTPlmc393QZQ/5rQadPhi7pBVEMZxyTi0Ii8=
 github.com/go-openapi/swag v0.19.0/go.mod h1:AByQ+nYG6gQg71GINrmuDXCPWdL640yX49/kXLo40Tg=
@@ -58,7 +56,6 @@ github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/golang/groupcache v0.0.0-20181024230925-c65c006176ff h1:kOkM9whyQYodu09SJ6W3NCsHG7crFaJILQ22Gozp3lg=
 github.com/golang/groupcache v0.0.0-20181024230925-c65c006176ff/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
-github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -89,7 +86,6 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kylelemons/godebug v0.0.0-20170820004349-d65d576e9348 h1:MtvEpTB6LX3vkb4ax0b5D2DHbNAUsen0Gx5wZoq3lV4=
 github.com/kylelemons/godebug v0.0.0-20170820004349-d65d576e9348/go.mod h1:B69LEHPfb2qLo0BaaOLcbitczOKLWTsrBG9LczfCD4k=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
-github.com/mailru/easyjson v0.0.0-20180823135443-60711f1a8329 h1:2gxZ0XQIU/5z3Z3bUBu+FXuk2pFbkN6tcwi/pjyaDic=
 github.com/mailru/easyjson v0.0.0-20180823135443-60711f1a8329/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
 github.com/mailru/easyjson v0.0.0-20190403194419-1ea4449da983 h1:wL11wNW7dhKIcRCHSm4sHKPWz0tt4mwBsVodG7+Xyqg=
 github.com/mailru/easyjson v0.0.0-20190403194419-1ea4449da983/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
@@ -129,7 +125,6 @@ github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
@@ -147,12 +142,10 @@ golang.org/x/lint v0.0.0-20190409202823-959b441ac422 h1:QzoH/1pFpZguR8NrRHLcO6jK
 golang.org/x/lint v0.0.0-20190409202823-959b441ac422/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20181005035420-146acd28ed58 h1:otZG8yDCO4LVps5+9bxOeNiCvgmOyt96J3roHTYs7oE=
 golang.org/x/net v0.0.0-20181005035420-146acd28ed58/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181201002055-351d144fa1fc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190501004415-9ce7a6920f09 h1:KaQtG+aDELoNmXYas3TVkGNYRuq8JQ1aa7LJt8EXVyo=
 golang.org/x/net v0.0.0-20190501004415-9ce7a6920f09/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@@ -164,18 +157,15 @@ golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181205085412-a5c9d58dba9a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190429190828-d89cdac9e872 h1:cGjJzUd8RgBw428LXP65YXni0aiGNA4Bl+ls8SmLOm8=
 golang.org/x/sys v0.0.0-20190429190828-d89cdac9e872/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c h1:fqgJT0MGcGpPgpWU7VRdRjuArfcOvC4AoJmILihzhDg=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e h1:FDhOuMEY4JVRztM/gsbk+IKUQ8kj74bxZrgw87eMMVc=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190328211700-ab21143f2384 h1:TFlARGu6Czu1z7q93HTxcP1P+/ZFC/IKythI5RzrnRg=
@@ -183,7 +173,6 @@ golang.org/x/tools v0.0.0-20190328211700-ab21143f2384/go.mod h1:LCzVGOaR6xXOjkQ3
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/appengine v1.5.0 h1:KxkO13IPW4Lslp2bz+KHP2E3gtFlrIGNThxkZQ3g+4c=
 google.golang.org/appengine v1.5.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

manifests/kilo-k3s-userspace-heterogeneous.yaml

@@ -0,0 +1,349 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: kilo
+  namespace: kube-system
+  labels:
+    app.kubernetes.io/name: kilo
+data:
+  cni-conf.json: |
+    {
+       "cniVersion":"0.3.1",
+       "name":"kilo",
+       "plugins":[
+          {
+             "name":"kubernetes",
+             "type":"bridge",
+             "bridge":"kube-bridge",
+             "isDefaultGateway":true,
+             "forceAddress":true,
+             "mtu": 1420,
+             "ipam":{
+                "type":"host-local"
+             }
+          },
+          {
+             "type":"portmap",
+             "snat":true,
+             "capabilities":{
+                "portMappings":true
+             }
+          }
+       ]
+    }
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: kilo
+  namespace: kube-system
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: kilo
+rules:
+- apiGroups:
+  - ""
+  resources:
+  - nodes
+  verbs:
+  - list
+  - get
+  - patch
+  - watch
+- apiGroups:
+  - kilo.squat.ai
+  resources:
+  - peers
+  verbs:
+  - list
+  - update
+  - watch
+- apiGroups:
+  - apiextensions.k8s.io
+  resources:
+  - customresourcedefinitions
+  verbs:
+  - create
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: kilo
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: kilo
+subjects:
+  - kind: ServiceAccount
+    name: kilo
+    namespace: kube-system
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: kilo
+  namespace: kube-system
+  labels:
+    app.kubernetes.io/name: kilo
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: kilo
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: kilo
+    spec:
+      nodeSelector:
+        nkml.squat.ai/wireguard: "true"
+      serviceAccountName: kilo
+      hostNetwork: true
+      containers:
+      - name: kilo
+        image: squat/kilo
+        args:
+        - --kubeconfig=/etc/kubernetes/kubeconfig
+        - --hostname=$(NODE_NAME)
+        - --interface=kilo0
+        env:
+        - name: NODE_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: spec.nodeName
+        securityContext:
+          privileged: true
+        volumeMounts:
+        - name: cni-conf-dir
+          mountPath: /etc/cni/net.d
+        - name: kilo-dir
+          mountPath: /var/lib/kilo
+        - name: kubeconfig
+          mountPath: /etc/kubernetes/kubeconfig
+          readOnly: true
+        - name: lib-modules
+          mountPath: /lib/modules
+          readOnly: true
+        - name: xtables-lock
+          mountPath: /run/xtables.lock
+          readOnly: false
+      initContainers:
+      - name: install-cni
+        image: squat/kilo
+        command:
+        - /bin/sh
+        - -c
+        - set -e -x;
+          cp /opt/cni/bin/* /host/opt/cni/bin/;
+          TMP_CONF="$CNI_CONF_NAME".tmp;
+          echo "$CNI_NETWORK_CONFIG" > $TMP_CONF;
+          rm -f /host/etc/cni/net.d/*;
+          mv $TMP_CONF /host/etc/cni/net.d/$CNI_CONF_NAME
+        env:
+        - name: CNI_CONF_NAME
+          value: 10-kilo.conflist
+        - name: CNI_NETWORK_CONFIG
+          valueFrom:
+            configMapKeyRef:
+              name: kilo
+              key: cni-conf.json
+        volumeMounts:
+        - name: cni-bin-dir
+          mountPath: /host/opt/cni/bin
+        - name: cni-conf-dir
+          mountPath: /host/etc/cni/net.d
+      tolerations:
+      - effect: NoSchedule
+        operator: Exists
+      - effect: NoExecute
+        operator: Exists
+      volumes:
+      - name: cni-bin-dir
+        hostPath:
+          path: /opt/cni/bin
+      - name: cni-conf-dir
+        hostPath:
+          path: /etc/cni/net.d
+      - name: kilo-dir
+        hostPath:
+          path: /var/lib/kilo
+      - name: kubeconfig
+        hostPath: 
+          # Since kilo runs as a daemonset, it is recommended that you copy the
+          # k3s.yaml kubeconfig file from the master node to all worker nodes
+          # with the same path structure.
+          path: /etc/rancher/k3s/k3s.yaml
+      - name: lib-modules
+        hostPath:
+          path: /lib/modules
+      - name: xtables-lock
+        hostPath:
+          path: /run/xtables.lock
+          type: FileOrCreate
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: kilo-userspace
+  namespace: kube-system
+  labels:
+    app.kubernetes.io/name: kilo-userspace
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: kilo-userspace
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: kilo-userspace
+    spec:
+      nodeSelector:
+        nkml.squat.ai/wireguard: "false"
+      serviceAccountName: kilo
+      hostNetwork: true
+      containers:
+      - name: kilo
+        image: squat/kilo 
+        args:
+        - --kubeconfig=/etc/kubernetes/kubeconfig
+        - --hostname=$(NODE_NAME)
+        - --create-interface=false
+        - --interface=kilo0
+        env:
+        - name: NODE_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: spec.nodeName
+        securityContext:
+          privileged: true
+        volumeMounts:
+        - name: cni-conf-dir
+          mountPath: /etc/cni/net.d
+        - name: kilo-dir
+          mountPath: /var/lib/kilo
+        - name: kubeconfig
+          mountPath: /etc/kubernetes/kubeconfig
+          readOnly: true
+        - name: lib-modules
+          mountPath: /lib/modules
+          readOnly: true
+        - name: xtables-lock
+          mountPath: /run/xtables.lock
+          readOnly: false
+        - name: wireguard
+          mountPath: /var/run/wireguard
+          readOnly: false
+      - name: boringtun
+        image: leonnicolas/boringtun
+        args:
+        - --disable-drop-privileges=true
+        - --foreground
+        - kilo0
+        securityContext:
+          privileged: true
+        volumeMounts:
+        - name: wireguard
+          mountPath: /var/run/wireguard
+          readOnly: false
+      initContainers:
+      - name: install-cni
+        image: squat/kilo
+        command:
+        - /bin/sh
+        - -c
+        - set -e -x;
+          cp /opt/cni/bin/* /host/opt/cni/bin/;
+          TMP_CONF="$CNI_CONF_NAME".tmp;
+          echo "$CNI_NETWORK_CONFIG" > $TMP_CONF;
+          rm -f /host/etc/cni/net.d/*;
+          mv $TMP_CONF /host/etc/cni/net.d/$CNI_CONF_NAME
+        env:
+        - name: CNI_CONF_NAME
+          value: 10-kilo.conflist
+        - name: CNI_NETWORK_CONFIG
+          valueFrom:
+            configMapKeyRef:
+              name: kilo
+              key: cni-conf.json
+        volumeMounts:
+        - name: cni-bin-dir
+          mountPath: /host/opt/cni/bin
+        - name: cni-conf-dir
+          mountPath: /host/etc/cni/net.d
+      tolerations:
+      - effect: NoSchedule
+        operator: Exists
+      - effect: NoExecute
+        operator: Exists
+      volumes:
+      - name: cni-bin-dir
+        hostPath:
+          path: /opt/cni/bin
+      - name: cni-conf-dir
+        hostPath:
+          path: /etc/cni/net.d
+      - name: kilo-dir
+        hostPath:
+          path: /var/lib/kilo
+      - name: kubeconfig
+        hostPath: 
+          # Since kilo runs as a daemonset, it is recommended that you copy the
+          # k3s.yaml kubeconfig file from the master node to all worker nodes
+          # with the same path structure.
+          path: /etc/rancher/k3s/k3s.yaml
+      - name: lib-modules
+        hostPath:
+          path: /lib/modules
+      - name: xtables-lock
+        hostPath:
+          path: /run/xtables.lock
+          type: FileOrCreate
+      - name: wireguard
+        hostPath:
+          path: /var/run/wireguard
+---
+kind: DaemonSet
+apiVersion: apps/v1
+metadata: 
+  name: nkml
+  namespace: kube-system
+  labels:
+    app.kubernetes.io/name: nkml
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: nkml
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: nkml
+    spec:
+      hostNetwork: true
+      containers:
+      - name: nkml
+        image: leonnicolas/nkml
+        args: 
+        - --hostname=$(NODE_NAME)
+        - --label-mod=wireguard
+        - --kubeconfig=/etc/kubernetes/kubeconfig
+        env:
+        - name: NODE_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: spec.nodeName
+        ports:
+        - name: http
+          containerPort: 8080
+        volumeMounts:
+        - name: kubeconfig
+          mountPath: /etc/kubernetes/kubeconfig
+          readOnly: true
+      volumes:
+      - name: kubeconfig
+        hostPath: 
+          # since the above DaemonSets are dependant on the labels
+          # and nkml would need a cni to start
+          # it needs run on the hostnetwork and use the kubeconfig
+          # to label the nodes
+          path: /etc/rancher/k3s/k3s.yaml

manifests/kilo-k3s-userspace.yaml

@@ -0,0 +1,199 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: kilo
+  namespace: kube-system
+  labels:
+    app.kubernetes.io/name: kilo
+data:
+  cni-conf.json: |
+    {
+       "cniVersion":"0.3.1",
+       "name":"kilo",
+       "plugins":[
+          {
+             "name":"kubernetes",
+             "type":"bridge",
+             "bridge":"kube-bridge",
+             "isDefaultGateway":true,
+             "forceAddress":true,
+             "mtu": 1420,
+             "ipam":{
+                "type":"host-local"
+             }
+          },
+          {
+             "type":"portmap",
+             "snat":true,
+             "capabilities":{
+                "portMappings":true
+             }
+          }
+       ]
+    }
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: kilo
+  namespace: kube-system
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: kilo
+rules:
+- apiGroups:
+  - ""
+  resources:
+  - nodes
+  verbs:
+  - list
+  - patch
+  - watch
+- apiGroups:
+  - kilo.squat.ai
+  resources:
+  - peers
+  verbs:
+  - list
+  - update
+  - watch
+- apiGroups:
+  - apiextensions.k8s.io
+  resources:
+  - customresourcedefinitions
+  verbs:
+  - create
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: kilo
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: kilo
+subjects:
+  - kind: ServiceAccount
+    name: kilo
+    namespace: kube-system
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: kilo
+  namespace: kube-system
+  labels:
+    app.kubernetes.io/name: kilo
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: kilo
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: kilo
+    spec:
+      serviceAccountName: kilo
+      hostNetwork: true
+      containers:
+      - name: kilo
+        image: squat/kilo
+        args:
+        - --kubeconfig=/etc/kubernetes/kubeconfig
+        - --hostname=$(NODE_NAME)
+        - --create-interface=false
+        - --interface=kilo0
+        env:
+        - name: NODE_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: spec.nodeName
+        securityContext:
+          privileged: true
+        volumeMounts:
+        - name: cni-conf-dir
+          mountPath: /etc/cni/net.d
+        - name: kilo-dir
+          mountPath: /var/lib/kilo
+        - name: kubeconfig
+          mountPath: /etc/kubernetes/kubeconfig
+          readOnly: true
+        - name: lib-modules
+          mountPath: /lib/modules
+          readOnly: true
+        - name: xtables-lock
+          mountPath: /run/xtables.lock
+          readOnly: false
+        - name: wireguard
+          mountPath: /var/run/wireguard
+          readOnly: false
+      - name: boringtun
+        image: leonnicolas/boringtun
+        args:
+        - --disable-drop-privileges=true
+        - --foreground
+        - kilo0
+        securityContext:
+          privileged: true
+        volumeMounts:
+        - name: wireguard
+          mountPath: /var/run/wireguard
+          readOnly: false
+      initContainers:
+      - name: install-cni
+        image: squat/kilo
+        command:
+        - /bin/sh
+        - -c
+        - set -e -x;
+          cp /opt/cni/bin/* /host/opt/cni/bin/;
+          TMP_CONF="$CNI_CONF_NAME".tmp;
+          echo "$CNI_NETWORK_CONFIG" > $TMP_CONF;
+          rm -f /host/etc/cni/net.d/*;
+          mv $TMP_CONF /host/etc/cni/net.d/$CNI_CONF_NAME
+        env:
+        - name: CNI_CONF_NAME
+          value: 10-kilo.conflist
+        - name: CNI_NETWORK_CONFIG
+          valueFrom:
+            configMapKeyRef:
+              name: kilo
+              key: cni-conf.json
+        volumeMounts:
+        - name: cni-bin-dir
+          mountPath: /host/opt/cni/bin
+        - name: cni-conf-dir
+          mountPath: /host/etc/cni/net.d
+      tolerations:
+      - effect: NoSchedule
+        operator: Exists
+      - effect: NoExecute
+        operator: Exists
+      volumes:
+      - name: cni-bin-dir
+        hostPath:
+          path: /opt/cni/bin
+      - name: cni-conf-dir
+        hostPath:
+          path: /etc/cni/net.d
+      - name: kilo-dir
+        hostPath:
+          path: /var/lib/kilo
+      - name: kubeconfig
+        hostPath: 
+          # Since kilo runs as a daemonset, it is recommended that you copy the
+          # k3s.yaml kubeconfig file from the master node to all worker nodes
+          # with the same path structure.
+          path: /etc/rancher/k3s/k3s.yaml
+      - name: lib-modules
+        hostPath:
+          path: /lib/modules
+      - name: xtables-lock
+        hostPath:
+          path: /run/xtables.lock
+          type: FileOrCreate
+      - name: wireguard
+        hostPath:
+          path: /var/run/wireguard

manifests/kilo-kubeadm.yaml

@@ -160,7 +160,7 @@ spec:
           path: /opt/cni/bin
       - name: cni-conf-dir
         hostPath:
-          path: /etc/kubernetes/cni/net.d
+          path: /etc/cni/net.d
       - name: kilo-dir
         hostPath:
           path: /var/lib/kilo

pkg/encapsulation/ipip.go

@@ -67,17 +67,18 @@ func (i *ipip) Init(base int) error {
 // when traffic between nodes must be encapsulated.
 func (i *ipip) Rules(nodes []*net.IPNet) []iptables.Rule {
 	var rules []iptables.Rule
+	proto := ipipProtocolName()
 	rules = append(rules, iptables.NewIPv4Chain("filter", "KILO-IPIP"))
 	rules = append(rules, iptables.NewIPv6Chain("filter", "KILO-IPIP"))
-	rules = append(rules, iptables.NewIPv4Rule("filter", "INPUT", "-m", "comment", "--comment", "Kilo: jump to IPIP chain", "-p", "4", "-j", "KILO-IPIP"))
-	rules = append(rules, iptables.NewIPv6Rule("filter", "INPUT", "-m", "comment", "--comment", "Kilo: jump to IPIP chain", "-p", "4", "-j", "KILO-IPIP"))
+	rules = append(rules, iptables.NewIPv4Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: jump to IPIP chain", "-j", "KILO-IPIP"))
+	rules = append(rules, iptables.NewIPv6Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: jump to IPIP chain", "-j", "KILO-IPIP"))
 	for _, n := range nodes {
 		// Accept encapsulated traffic from peers.
-		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(n.IP)), "filter", "KILO-IPIP", "-m", "comment", "--comment", "Kilo: allow IPIP traffic", "-s", n.IP.String(), "-j", "ACCEPT"))
+		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(n.IP)), "filter", "KILO-IPIP", "-s", n.String(), "-m", "comment", "--comment", "Kilo: allow IPIP traffic", "-j", "ACCEPT"))
 	}
 	// Drop all other IPIP traffic.
-	rules = append(rules, iptables.NewIPv4Rule("filter", "INPUT", "-m", "comment", "--comment", "Kilo: reject other IPIP traffic", "-p", "4", "-j", "DROP"))
-	rules = append(rules, iptables.NewIPv6Rule("filter", "INPUT", "-m", "comment", "--comment", "Kilo: reject other IPIP traffic", "-p", "4", "-j", "DROP"))
+	rules = append(rules, iptables.NewIPv4Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: reject other IPIP traffic", "-j", "DROP"))
+	rules = append(rules, iptables.NewIPv6Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: reject other IPIP traffic", "-j", "DROP"))
 
 	return rules
 }

pkg/encapsulation/ipip_cgo.go

@@ -0,0 +1,26 @@
+// Copyright 2021 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build cgo
+
+package encapsulation
+
+/*
+#include <netdb.h>
+*/
+import "C"
+
+func ipipProtocolName() string {
+	return C.GoString(C.getprotobynumber(4).p_name)
+}

pkg/encapsulation/ipip_nocgo.go

@@ -0,0 +1,24 @@
+// Copyright 2021 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !cgo
+
+package encapsulation
+
+// If we can determine the protocol name at runtime
+// by looking it up in the protocols database, assume `ipencap`
+// as this is the value in Kilo's container image.
+func ipipProtocolName() string {
+	return "ipencap"
+}

pkg/encapsulation/noop.go

@@ -0,0 +1,59 @@
+// Copyright 2021 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package encapsulation
+
+import (
+	"net"
+
+	"github.com/squat/kilo/pkg/iptables"
+)
+
+// Noop is an encapsulation that does nothing.
+type Noop Strategy
+
+// CleanUp will also do nothing.
+func (n Noop) CleanUp() error {
+	return nil
+}
+
+// Gw will also do nothing.
+func (n Noop) Gw(_ net.IP, _ net.IP, _ *net.IPNet) net.IP {
+	return nil
+}
+
+// Index will also do nothing.
+func (n Noop) Index() int {
+	return 0
+}
+
+// Init will also do nothing.
+func (n Noop) Init(_ int) error {
+	return nil
+}
+
+// Rules will also do nothing.
+func (n Noop) Rules(_ []*net.IPNet) []iptables.Rule {
+	return nil
+}
+
+// Set will also do nothing.
+func (n Noop) Set(_ *net.IPNet) error {
+	return nil
+}
+
+// Strategy will finally do nothing.
+func (n Noop) Strategy() Strategy {
+	return Strategy(n)
+}

pkg/iptables/fake.go

@@ -16,6 +16,8 @@ package iptables
 
 import (
 	"fmt"
+	"strings"
+	"sync/atomic"
 
 	"github.com/coreos/go-iptables/iptables"
 )
@@ -38,12 +40,14 @@ func (s statusError) ExitStatus() int {
 }
 
 type fakeClient struct {
+	calls   uint64
 	storage []Rule
 }
 
 var _ Client = &fakeClient{}
 
 func (f *fakeClient) AppendUnique(table, chain string, spec ...string) error {
+	atomic.AddUint64(&f.calls, 1)
 	exists, err := f.Exists(table, chain, spec...)
 	if err != nil {
 		return err
@@ -56,6 +60,7 @@ func (f *fakeClient) AppendUnique(table, chain string, spec ...string) error {
 }
 
 func (f *fakeClient) Delete(table, chain string, spec ...string) error {
+	atomic.AddUint64(&f.calls, 1)
 	r := &rule{table: table, chain: chain, spec: spec}
 	for i := range f.storage {
 		if f.storage[i].String() == r.String() {
@@ -69,6 +74,7 @@ func (f *fakeClient) Delete(table, chain string, spec ...string) error {
 }
 
 func (f *fakeClient) Exists(table, chain string, spec ...string) (bool, error) {
+	atomic.AddUint64(&f.calls, 1)
 	r := &rule{table: table, chain: chain, spec: spec}
 	for i := range f.storage {
 		if f.storage[i].String() == r.String() {
@@ -78,7 +84,22 @@ func (f *fakeClient) Exists(table, chain string, spec ...string) (bool, error) {
 	return false, nil
 }
 
+func (f *fakeClient) List(table, chain string) ([]string, error) {
+	atomic.AddUint64(&f.calls, 1)
+	var rs []string
+	for i := range f.storage {
+		switch r := f.storage[i].(type) {
+		case *rule:
+			if r.table == table && r.chain == chain {
+				rs = append(rs, strings.TrimSpace(strings.TrimPrefix(r.String(), table)))
+			}
+		}
+	}
+	return rs, nil
+}
+
 func (f *fakeClient) ClearChain(table, name string) error {
+	atomic.AddUint64(&f.calls, 1)
 	for i := range f.storage {
 		r, ok := f.storage[i].(*rule)
 		if !ok {
@@ -90,10 +111,14 @@ func (f *fakeClient) ClearChain(table, name string) error {
 			}
 		}
 	}
-	return f.DeleteChain(table, name)
+	if err := f.DeleteChain(table, name); err != nil {
+		return err
+	}
+	return f.NewChain(table, name)
 }
 
 func (f *fakeClient) DeleteChain(table, name string) error {
+	atomic.AddUint64(&f.calls, 1)
 	for i := range f.storage {
 		r, ok := f.storage[i].(*rule)
 		if !ok {
@@ -116,6 +141,7 @@ func (f *fakeClient) DeleteChain(table, name string) error {
 }
 
 func (f *fakeClient) NewChain(table, name string) error {
+	atomic.AddUint64(&f.calls, 1)
 	c := &chain{table: table, chain: name}
 	for i := range f.storage {
 		if f.storage[i].String() == c.String() {
@@ -125,3 +151,17 @@ func (f *fakeClient) NewChain(table, name string) error {
 	f.storage = append(f.storage, c)
 	return nil
 }
+
+func (f *fakeClient) ListChains(table string) ([]string, error) {
+	atomic.AddUint64(&f.calls, 1)
+	var cs []string
+	for i := range f.storage {
+		switch c := f.storage[i].(type) {
+		case *chain:
+			if c.table == table {
+				cs = append(cs, c.chain)
+			}
+		}
+	}
+	return cs, nil
+}

pkg/iptables/iptables.go

@@ -17,11 +17,12 @@ package iptables
 import (
 	"fmt"
 	"net"
-	"strings"
 	"sync"
 	"time"
 
 	"github.com/coreos/go-iptables/iptables"
+	"github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/log/level"
 )
 
 // Protocol represents an IP protocol.
@@ -47,9 +48,11 @@ type Client interface {
 	AppendUnique(table string, chain string, rule ...string) error
 	Delete(table string, chain string, rule ...string) error
 	Exists(table string, chain string, rule ...string) (bool, error)
+	List(table string, chain string) ([]string, error)
 	ClearChain(table string, chain string) error
 	DeleteChain(table string, chain string) error
 	NewChain(table string, chain string) error
+	ListChains(table string) ([]string, error)
 }
 
 // Rule is an interface for interacting with iptables objects.
@@ -107,7 +110,17 @@ func (r *rule) String() string {
 	if r == nil {
 		return ""
 	}
-	return fmt.Sprintf("%s_%s_%s", r.table, r.chain, strings.Join(r.spec, "_"))
+	spec := r.table + " -A " + r.chain
+	for i, s := range r.spec {
+		spec += " "
+		// If this is the content of a comment, wrap the value in quotes.
+		if i > 0 && r.spec[i-1] == "--comment" {
+			spec += `"` + s + `"`
+		} else {
+			spec += s
+		}
+	}
+	return spec
 }
 
 func (r *rule) Proto() Protocol {
@@ -132,6 +145,7 @@ func NewIPv6Chain(table, name string) Rule {
 }
 
 func (c *chain) Add(client Client) error {
+	// Note: `ClearChain` creates a chain if it does not exist.
 	if err := client.ClearChain(c.table, c.chain); err != nil {
 		return fmt.Errorf("failed to add iptables chain: %v", err)
 	}
@@ -171,41 +185,81 @@ func (c *chain) String() string {
 	if c == nil {
 		return ""
 	}
-	return fmt.Sprintf("%s_%s", c.table, c.chain)
+	return chainToString(c.table, c.chain)
 }
 
 func (c *chain) Proto() Protocol {
 	return c.proto
 }
 
+func chainToString(table, chain string) string {
+	return fmt.Sprintf("%s -N %s", table, chain)
+}
+
 // Controller is able to reconcile a given set of iptables rules.
 type Controller struct {
-	v4     Client
-	v6     Client
-	errors chan error
+	v4           Client
+	v6           Client
+	errors       chan error
+	logger       log.Logger
+	resyncPeriod time.Duration
 
 	sync.Mutex
 	rules      []Rule
 	subscribed bool
 }
 
+// ControllerOption modifies the controller's configuration.
+type ControllerOption func(h *Controller)
+
+// WithLogger adds a logger to the controller.
+func WithLogger(logger log.Logger) ControllerOption {
+	return func(c *Controller) {
+		c.logger = logger
+	}
+}
+
+// WithResyncPeriod modifies how often the controller reconciles.
+func WithResyncPeriod(resyncPeriod time.Duration) ControllerOption {
+	return func(c *Controller) {
+		c.resyncPeriod = resyncPeriod
+	}
+}
+
+// WithClients adds iptables clients to the controller.
+func WithClients(v4, v6 Client) ControllerOption {
+	return func(c *Controller) {
+		c.v4 = v4
+		c.v6 = v6
+	}
+}
+
 // New generates a new iptables rules controller.
-// It expects an IP address length to determine
-// whether to operate in IPv4 or IPv6 mode.
-func New() (*Controller, error) {
-	v4, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create iptables IPv4 client: %v", err)
-	}
-	v6, err := iptables.NewWithProtocol(iptables.ProtocolIPv6)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create iptables IPv6 client: %v", err)
-	}
-	return &Controller{
-		v4:     v4,
-		v6:     v6,
+// If no options are given, IPv4 and IPv6 clients
+// will be instantiated using the regular iptables backend.
+func New(opts ...ControllerOption) (*Controller, error) {
+	c := &Controller{
 		errors: make(chan error),
-	}, nil
+		logger: log.NewNopLogger(),
+	}
+	for _, o := range opts {
+		o(c)
+	}
+	if c.v4 == nil {
+		v4, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create iptables IPv4 client: %v", err)
+		}
+		c.v4 = v4
+	}
+	if c.v6 == nil {
+		v6, err := iptables.NewWithProtocol(iptables.ProtocolIPv6)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create iptables IPv6 client: %v", err)
+		}
+		c.v6 = v6
+	}
+	return c, nil
 }
 
 // Run watches for changes to iptables rules and reconciles
@@ -220,16 +274,18 @@ func (c *Controller) Run(stop <-chan struct{}) (<-chan error, error) {
 	c.subscribed = true
 	c.Unlock()
 	go func() {
+		t := time.NewTimer(c.resyncPeriod)
 		defer close(c.errors)
 		for {
 			select {
-			case <-time.After(5 * time.Second):
+			case <-t.C:
+				if err := c.reconcile(); err != nil {
+					nonBlockingSend(c.errors, fmt.Errorf("failed to reconcile rules: %v", err))
+				}
+				t.Reset(c.resyncPeriod)
 			case <-stop:
 				return
 			}
-			if err := c.reconcile(); err != nil {
-				nonBlockingSend(c.errors, fmt.Errorf("failed to reconcile rules: %v", err))
-			}
 		}
 	}()
 	return c.errors, nil
@@ -242,12 +298,14 @@ func (c *Controller) Run(stop <-chan struct{}) (<-chan error, error) {
 func (c *Controller) reconcile() error {
 	c.Lock()
 	defer c.Unlock()
+	var rc ruleCache
 	for i, r := range c.rules {
-		ok, err := r.Exists(c.client(r.Proto()))
+		ok, err := rc.exists(c.client(r.Proto()), r)
 		if err != nil {
 			return fmt.Errorf("failed to check if rule exists: %v", err)
 		}
 		if !ok {
+			level.Info(c.logger).Log("msg", fmt.Sprintf("applying %d iptables rules", len(c.rules)-i))
 			if err := c.resetFromIndex(i, c.rules); err != nil {
 				return fmt.Errorf("failed to add rule: %v", err)
 			}

pkg/iptables/iptables_test.go

@@ -83,10 +83,11 @@ func TestSet(t *testing.T) {
 			},
 		},
 	} {
-		controller := &Controller{}
 		client := &fakeClient{}
-		controller.v4 = client
-		controller.v6 = client
+		controller, err := New(WithClients(client, client))
+		if err != nil {
+			t.Fatalf("test case %q: got unexpected error instantiating controller: %v", tc.name, err)
+		}
 		for i := range tc.sets {
 			if err := controller.Set(tc.sets[i]); err != nil {
 				t.Fatalf("test case %q: got unexpected error seting rule set %d: %v", tc.name, i, err)
@@ -139,10 +140,11 @@ func TestCleanUp(t *testing.T) {
 			rules: []Rule{rules[0], rules[1]},
 		},
 	} {
-		controller := &Controller{}
 		client := &fakeClient{}
-		controller.v4 = client
-		controller.v6 = client
+		controller, err := New(WithClients(client, client))
+		if err != nil {
+			t.Fatalf("test case %q: got unexpected error instantiating controller: %v", tc.name, err)
+		}
 		if err := controller.Set(tc.rules); err != nil {
 			t.Fatalf("test case %q: Set should not fail: %v", tc.name, err)
 		}

pkg/iptables/rulecache.go

@@ -0,0 +1,106 @@
+// Copyright 2021 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package iptables
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ruleCacheFlag byte
+
+const (
+	exists ruleCacheFlag = 1 << iota
+	populated
+)
+
+type isNotExistError interface {
+	error
+	IsNotExist() bool
+}
+
+// ruleCache is a lazy cache that can be used to
+// check if a given rule or chain exists in an iptables
+// table.
+type ruleCache [2]map[string]ruleCacheFlag
+
+func (rc *ruleCache) populateTable(c Client, proto Protocol, table string) error {
+	// If the table already exists in the destination map,
+	// exit early since it has already been populated.
+	if rc[proto][table]&populated != 0 {
+		return nil
+	}
+	cs, err := c.ListChains(table)
+	if err != nil {
+		return fmt.Errorf("failed to populate chains for table %q: %v", table, err)
+	}
+	rc[proto][table] = exists | populated
+	for i := range cs {
+		rc[proto][chainToString(table, cs[i])] |= exists
+	}
+	return nil
+}
+
+func (rc *ruleCache) populateChain(c Client, proto Protocol, table, chain string) error {
+	// If the destination chain true, then it has already been populated.
+	if rc[proto][chainToString(table, chain)]&populated != 0 {
+		return nil
+	}
+	rs, err := c.List(table, chain)
+	if err != nil {
+		if existsErr, ok := err.(isNotExistError); ok && existsErr.IsNotExist() {
+			rc[proto][chainToString(table, chain)] = populated
+			return nil
+		}
+		return fmt.Errorf("failed to populate rules in chain %q for table %q: %v", chain, table, err)
+	}
+	for i := range rs {
+		rc[proto][strings.Join([]string{table, rs[i]}, " ")] = exists
+	}
+	// If there are rules on the chain, then the chain exists too.
+	if len(rs) > 0 {
+		rc[proto][chainToString(table, chain)] = exists
+	}
+	rc[proto][chainToString(table, chain)] |= populated
+	return nil
+}
+
+func (rc *ruleCache) populateRules(c Client, r Rule) error {
+	// Ensure a map for the proto exists.
+	if rc[r.Proto()] == nil {
+		rc[r.Proto()] = make(map[string]ruleCacheFlag)
+	}
+
+	if ch, ok := r.(*chain); ok {
+		return rc.populateTable(c, r.Proto(), ch.table)
+	}
+
+	ru := r.(*rule)
+	return rc.populateChain(c, r.Proto(), ru.table, ru.chain)
+}
+
+func (rc *ruleCache) exists(c Client, r Rule) (bool, error) {
+	// Exit early if the exact rule exists by name.
+	if rc[r.Proto()][r.String()]&exists != 0 {
+		return true, nil
+	}
+
+	// Otherwise, populate the respective rules.
+	if err := rc.populateRules(c, r); err != nil {
+		return false, err
+	}
+
+	return rc[r.Proto()][r.String()]&exists != 0, nil
+}

pkg/iptables/rulecache_test.go

@@ -0,0 +1,125 @@
+// Copyright 2021 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package iptables
+
+import (
+	"testing"
+)
+
+func TestRuleCache(t *testing.T) {
+	for _, tc := range []struct {
+		name  string
+		rules []Rule
+		check []Rule
+		out   []bool
+		calls uint64
+	}{
+		{
+			name:  "empty",
+			rules: nil,
+			check: []Rule{rules[0]},
+			out:   []bool{false},
+			calls: 1,
+		},
+		{
+			name:  "single negative",
+			rules: []Rule{rules[1]},
+			check: []Rule{rules[0]},
+			out:   []bool{false},
+			calls: 1,
+		},
+		{
+			name:  "single positive",
+			rules: []Rule{rules[1]},
+			check: []Rule{rules[1]},
+			out:   []bool{true},
+			calls: 1,
+		},
+		{
+			name:  "single chain",
+			rules: []Rule{&chain{"nat", "KILO-NAT", ProtocolIPv4}},
+			check: []Rule{&chain{"nat", "KILO-NAT", ProtocolIPv4}},
+			out:   []bool{true},
+			calls: 1,
+		},
+		{
+			name:  "rule on chain means chain exists",
+			rules: []Rule{rules[0]},
+			check: []Rule{rules[0], &chain{"filter", "FORWARD", ProtocolIPv4}},
+			out:   []bool{true, true},
+			calls: 1,
+		},
+		{
+			name:  "rule on chain does not mean table is fully populated",
+			rules: []Rule{rules[0], &chain{"filter", "INPUT", ProtocolIPv4}},
+			check: []Rule{rules[0], &chain{"filter", "OUTPUT", ProtocolIPv4}, &chain{"filter", "INPUT", ProtocolIPv4}},
+			out:   []bool{true, false, true},
+			calls: 2,
+		},
+		{
+			name:  "multiple rules on chain",
+			rules: []Rule{rules[0], rules[1]},
+			check: []Rule{rules[0], rules[1], &chain{"filter", "FORWARD", ProtocolIPv4}},
+			out:   []bool{true, true, true},
+			calls: 1,
+		},
+		{
+			name:  "checking rule on chain does not mean chain exists",
+			rules: nil,
+			check: []Rule{rules[0], &chain{"filter", "FORWARD", ProtocolIPv4}},
+			out:   []bool{false, false},
+			calls: 2,
+		},
+		{
+			name:  "multiple chains on same table",
+			rules: nil,
+			check: []Rule{&chain{"filter", "INPUT", ProtocolIPv4}, &chain{"filter", "FORWARD", ProtocolIPv4}},
+			out:   []bool{false, false},
+			calls: 1,
+		},
+		{
+			name:  "multiple chains on different table",
+			rules: nil,
+			check: []Rule{&chain{"filter", "INPUT", ProtocolIPv4}, &chain{"nat", "POSTROUTING", ProtocolIPv4}},
+			out:   []bool{false, false},
+			calls: 2,
+		},
+	} {
+		controller := &Controller{}
+		client := &fakeClient{}
+		controller.v4 = client
+		controller.v6 = client
+		if err := controller.Set(tc.rules); err != nil {
+			t.Fatalf("test case %q: Set should not fail: %v", tc.name, err)
+		}
+		// Reset the client's calls so we can examine how many times
+		// the rule cache performs operations.
+		client.calls = 0
+		var rc ruleCache
+		for i := range tc.check {
+			ok, err := rc.exists(controller.client(tc.check[i].Proto()), tc.check[i])
+			if err != nil {
+				t.Fatalf("test case %q check %d: check should not fail: %v", tc.name, i, err)
+			}
+			if ok != tc.out[i] {
+				t.Errorf("test case %q check %d: expected %t, got %t", tc.name, i, tc.out[i], ok)
+			}
+		}
+		if client.calls != tc.calls {
+			t.Errorf("test case %q: expected client to be called %d times, got %d", tc.name, tc.calls, client.calls)
+		}
+	}
+
+}

pkg/k8s/apis/kilo/v1alpha1/openapi_generated.go

@@ -1,6 +1,6 @@
 // +build !ignore_autogenerated
 
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/apis/kilo/v1alpha1/types.go

@@ -19,9 +19,11 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"strings"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/validation"
 )
 
 const (
@@ -81,12 +83,22 @@ type PeerSpec struct {
 
 // PeerEndpoint represents a WireGuard enpoint, which is a ip:port tuple.
 type PeerEndpoint struct {
-	// IP must be a valid IP address.
-	IP string `json:"ip"`
+	DNSOrIP
 	// Port must be a valid port number.
 	Port uint32 `json:"port"`
 }
 
+// DNSOrIP represents either a DNS name or an IP address.
+// IPs, as they are more specific, are preferred.
+type DNSOrIP struct {
+	// DNS must be a valid RFC 1123 subdomain.
+	// +optional
+	DNS string `json:"dns,omitempty"`
+	// IP must be a valid IP address.
+	// +optional
+	IP string `json:"ip,omitempty"`
+}
+
 // PeerName is the peer resource's FQDN.
 var PeerName = PeerPlural + "." + GroupName
 
@@ -127,10 +139,18 @@ func (p *Peer) Validate() error {
 		}
 	}
 	if p.Spec.Endpoint != nil {
-		if net.ParseIP(p.Spec.Endpoint.IP) == nil {
+		if p.Spec.Endpoint.IP == "" && p.Spec.Endpoint.DNS == "" {
+			return errors.New("either an endpoint DNS name IP address must be given")
+		}
+		if p.Spec.Endpoint.DNS != "" {
+			if errs := validation.IsDNS1123Subdomain(p.Spec.Endpoint.DNS); len(errs) != 0 {
+				return errors.New(strings.Join(errs, "; "))
+			}
+		}
+		if p.Spec.Endpoint.IP != "" && net.ParseIP(p.Spec.Endpoint.IP) == nil {
 			return fmt.Errorf("failed to parse %q as a valid IP address", p.Spec.Endpoint.IP)
 		}
-		if p.Spec.Endpoint.Port == 0 {
+		if 1 > p.Spec.Endpoint.Port || p.Spec.Endpoint.Port > 65535 {
 			return fmt.Errorf("port must be a valid UDP port number, got %d", p.Spec.Endpoint.Port)
 		}
 	}

pkg/k8s/apis/kilo/v1alpha1/zz_generated.deepcopy.go

@@ -1,6 +1,6 @@
 // +build !ignore_autogenerated
 
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -22,6 +22,22 @@ import (
 	runtime "k8s.io/apimachinery/pkg/runtime"
 )
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *DNSOrIP) DeepCopyInto(out *DNSOrIP) {
+	*out = *in
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new DNSOrIP.
+func (in *DNSOrIP) DeepCopy() *DNSOrIP {
+	if in == nil {
+		return nil
+	}
+	out := new(DNSOrIP)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *Peer) DeepCopyInto(out *Peer) {
 	*out = *in
@@ -52,6 +68,7 @@ func (in *Peer) DeepCopyObject() runtime.Object {
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *PeerEndpoint) DeepCopyInto(out *PeerEndpoint) {
 	*out = *in
+	out.DNSOrIP = in.DNSOrIP
 	return
 }
 

pkg/k8s/backend.go

@@ -59,8 +59,8 @@ const (
 	locationAnnotationKey        = "kilo.squat.ai/location"
 	persistentKeepaliveKey       = "kilo.squat.ai/persistent-keepalive"
 	wireGuardIPAnnotationKey     = "kilo.squat.ai/wireguard-ip"
-
-	regionLabelKey  = "topology.kubernetes.io/region"
+	// RegionLabelKey is the key for the well-known Kubernetes topology region label.
+	RegionLabelKey  = "topology.kubernetes.io/region"
 	jsonPatchSlash  = "~1"
 	jsonRemovePatch = `{"op": "remove", "path": "%s"}`
 )
@@ -81,10 +81,11 @@ func (b *backend) Peers() mesh.PeerBackend {
 }
 
 type nodeBackend struct {
-	client   kubernetes.Interface
-	events   chan *mesh.NodeEvent
-	informer cache.SharedIndexInformer
-	lister   v1listers.NodeLister
+	client        kubernetes.Interface
+	events        chan *mesh.NodeEvent
+	informer      cache.SharedIndexInformer
+	lister        v1listers.NodeLister
+	topologyLabel string
 }
 
 type peerBackend struct {
@@ -96,16 +97,17 @@ type peerBackend struct {
 }
 
 // New creates a new instance of a mesh.Backend.
-func New(c kubernetes.Interface, kc kiloclient.Interface, ec apiextensions.Interface) mesh.Backend {
+func New(c kubernetes.Interface, kc kiloclient.Interface, ec apiextensions.Interface, topologyLabel string) mesh.Backend {
 	ni := v1informers.NewNodeInformer(c, 5*time.Minute, nil)
 	pi := v1alpha1informers.NewPeerInformer(kc, 5*time.Minute, nil)
 
 	return &backend{
 		&nodeBackend{
-			client:   c,
-			events:   make(chan *mesh.NodeEvent),
-			informer: ni,
-			lister:   v1listers.NewNodeLister(ni.GetIndexer()),
+			client:        c,
+			events:        make(chan *mesh.NodeEvent),
+			informer:      ni,
+			lister:        v1listers.NewNodeLister(ni.GetIndexer()),
+			topologyLabel: topologyLabel,
 		},
 		&peerBackend{
 			client:           kc,
@@ -138,7 +140,7 @@ func (nb *nodeBackend) Get(name string) (*mesh.Node, error) {
 	if err != nil {
 		return nil, err
 	}
-	return translateNode(n), nil
+	return translateNode(n, nb.topologyLabel), nil
 }
 
 // Init initializes the backend; for this backend that means
@@ -158,7 +160,7 @@ func (nb *nodeBackend) Init(stop <-chan struct{}) error {
 					// Failed to decode Node; ignoring...
 					return
 				}
-				nb.events <- &mesh.NodeEvent{Type: mesh.AddEvent, Node: translateNode(n)}
+				nb.events <- &mesh.NodeEvent{Type: mesh.AddEvent, Node: translateNode(n, nb.topologyLabel)}
 			},
 			UpdateFunc: func(old, obj interface{}) {
 				n, ok := obj.(*v1.Node)
@@ -171,7 +173,7 @@ func (nb *nodeBackend) Init(stop <-chan struct{}) error {
 					// Failed to decode Node; ignoring...
 					return
 				}
-				nb.events <- &mesh.NodeEvent{Type: mesh.UpdateEvent, Node: translateNode(n), Old: translateNode(o)}
+				nb.events <- &mesh.NodeEvent{Type: mesh.UpdateEvent, Node: translateNode(n, nb.topologyLabel), Old: translateNode(o, nb.topologyLabel)}
 			},
 			DeleteFunc: func(obj interface{}) {
 				n, ok := obj.(*v1.Node)
@@ -179,7 +181,7 @@ func (nb *nodeBackend) Init(stop <-chan struct{}) error {
 					// Failed to decode Node; ignoring...
 					return
 				}
-				nb.events <- &mesh.NodeEvent{Type: mesh.DeleteEvent, Node: translateNode(n)}
+				nb.events <- &mesh.NodeEvent{Type: mesh.DeleteEvent, Node: translateNode(n, nb.topologyLabel)}
 			},
 		},
 	)
@@ -194,7 +196,7 @@ func (nb *nodeBackend) List() ([]*mesh.Node, error) {
 	}
 	nodes := make([]*mesh.Node, len(ns))
 	for i := range ns {
-		nodes[i] = translateNode(ns[i])
+		nodes[i] = translateNode(ns[i], nb.topologyLabel)
 	}
 	return nodes, nil
 }
@@ -207,7 +209,11 @@ func (nb *nodeBackend) Set(name string, node *mesh.Node) error {
 	}
 	n := old.DeepCopy()
 	n.ObjectMeta.Annotations[endpointAnnotationKey] = node.Endpoint.String()
-	n.ObjectMeta.Annotations[internalIPAnnotationKey] = node.InternalIP.String()
+	if node.InternalIP == nil {
+		n.ObjectMeta.Annotations[internalIPAnnotationKey] = ""
+	} else {
+		n.ObjectMeta.Annotations[internalIPAnnotationKey] = node.InternalIP.String()
+	}
 	n.ObjectMeta.Annotations[keyAnnotationKey] = string(node.Key)
 	n.ObjectMeta.Annotations[lastSeenAnnotationKey] = strconv.FormatInt(node.LastSeen, 10)
 	if node.WireGuardIP == nil {
@@ -239,7 +245,7 @@ func (nb *nodeBackend) Watch() <-chan *mesh.NodeEvent {
 }
 
 // translateNode translates a Kubernetes Node to a mesh.Node.
-func translateNode(node *v1.Node) *mesh.Node {
+func translateNode(node *v1.Node, topologyLabel string) *mesh.Node {
 	if node == nil {
 		return nil
 	}
@@ -253,7 +259,7 @@ func translateNode(node *v1.Node) *mesh.Node {
 	// Allow the region to be overridden by an explicit location.
 	location, ok := node.ObjectMeta.Annotations[locationAnnotationKey]
 	if !ok {
-		location = node.ObjectMeta.Labels[regionLabelKey]
+		location = node.ObjectMeta.Labels[topologyLabel]
 	}
 	// Allow the endpoint to be overridden.
 	endpoint := parseEndpoint(node.ObjectMeta.Annotations[forceEndpointAnnotationKey])
@@ -265,6 +271,12 @@ func translateNode(node *v1.Node) *mesh.Node {
 	if internalIP == nil {
 		internalIP = normalizeIP(node.ObjectMeta.Annotations[internalIPAnnotationKey])
 	}
+	// Set the ForceInternalIP flag, if force-internal-ip annotation was set to "".
+	noInternalIP := false
+	if s, ok := node.ObjectMeta.Annotations[forceInternalIPAnnotationKey]; ok && (s == "" || s == "-") {
+		noInternalIP = true
+		internalIP = nil
+	}
 	// Set Wireguard PersistentKeepalive setting for the node.
 	var persistentKeepalive int64
 	if keepAlive, ok := node.ObjectMeta.Annotations[persistentKeepaliveKey]; !ok {
@@ -287,7 +299,10 @@ func translateNode(node *v1.Node) *mesh.Node {
 		// remote node's agent has not yet set its IP address;
 		// in this case the IP will be nil and
 		// the mesh can wait for the node to be updated.
+		// It is valid for the InternalIP to be nil,
+		// if the given node only has public IP addresses.
 		Endpoint:            endpoint,
+		NoInternalIP:        noInternalIP,
 		InternalIP:          internalIP,
 		Key:                 []byte(node.ObjectMeta.Annotations[keyAnnotationKey]),
 		LastSeen:            lastSeen,
@@ -325,10 +340,13 @@ func translatePeer(peer *v1alpha1.Peer) *mesh.Peer {
 		} else {
 			ip = ip.To16()
 		}
-		if peer.Spec.Endpoint.Port > 0 && ip != nil {
+		if peer.Spec.Endpoint.Port > 0 && (ip != nil || peer.Spec.Endpoint.DNS != "") {
 			endpoint = &wireguard.Endpoint{
-				DNSOrIP: wireguard.DNSOrIP{IP: ip},
-				Port:    peer.Spec.Endpoint.Port,
+				DNSOrIP: wireguard.DNSOrIP{
+					DNS: peer.Spec.Endpoint.DNS,
+					IP:  ip,
+				},
+				Port: peer.Spec.Endpoint.Port,
 			}
 		}
 	}
@@ -464,8 +482,15 @@ func (pb *peerBackend) Set(name string, peer *mesh.Peer) error {
 		p.Spec.AllowedIPs[i] = peer.AllowedIPs[i].String()
 	}
 	if peer.Endpoint != nil {
+		var ip string
+		if peer.Endpoint.IP != nil {
+			ip = peer.Endpoint.IP.String()
+		}
 		p.Spec.Endpoint = &v1alpha1.PeerEndpoint{
-			IP:   peer.Endpoint.IP.String(),
+			DNSOrIP: v1alpha1.DNSOrIP{
+				IP:  ip,
+				DNS: peer.Endpoint.DNS,
+			},
 			Port: peer.Endpoint.Port,
 		}
 	}

pkg/k8s/backend_test.go

@@ -83,7 +83,7 @@ func TestTranslateNode(t *testing.T) {
 		{
 			name: "region",
 			labels: map[string]string{
-				regionLabelKey: "a",
+				RegionLabelKey: "a",
 			},
 			out: &mesh.Node{
 				Location: "a",
@@ -95,7 +95,7 @@ func TestTranslateNode(t *testing.T) {
 				locationAnnotationKey: "b",
 			},
 			labels: map[string]string{
-				regionLabelKey: "a",
+				RegionLabelKey: "a",
 			},
 			out: &mesh.Node{
 				Location: "b",
@@ -137,7 +137,8 @@ func TestTranslateNode(t *testing.T) {
 				forceInternalIPAnnotationKey: "-10.1.0.2/24",
 			},
 			out: &mesh.Node{
-				InternalIP: &net.IPNet{IP: net.ParseIP("10.1.0.1"), Mask: net.CIDRMask(24, 32)},
+				InternalIP:   &net.IPNet{IP: net.ParseIP("10.1.0.1"), Mask: net.CIDRMask(24, 32)},
+				NoInternalIP: false,
 			},
 		},
 		{
@@ -147,7 +148,8 @@ func TestTranslateNode(t *testing.T) {
 				forceInternalIPAnnotationKey: "10.1.0.2/24",
 			},
 			out: &mesh.Node{
-				InternalIP: &net.IPNet{IP: net.ParseIP("10.1.0.2"), Mask: net.CIDRMask(24, 32)},
+				InternalIP:   &net.IPNet{IP: net.ParseIP("10.1.0.2"), Mask: net.CIDRMask(24, 32)},
+				NoInternalIP: false,
 			},
 		},
 		{
@@ -172,10 +174,11 @@ func TestTranslateNode(t *testing.T) {
 				wireGuardIPAnnotationKey:     "10.4.0.1/16",
 			},
 			labels: map[string]string{
-				regionLabelKey: "a",
+				RegionLabelKey: "a",
 			},
 			out: &mesh.Node{
 				Endpoint:            &wireguard.Endpoint{DNSOrIP: wireguard.DNSOrIP{IP: net.ParseIP("10.0.0.2")}, Port: 51821},
+				NoInternalIP:        false,
 				InternalIP:          &net.IPNet{IP: net.ParseIP("10.1.0.2"), Mask: net.CIDRMask(32, 32)},
 				Key:                 []byte("foo"),
 				LastSeen:            1000000000,
@@ -187,12 +190,68 @@ func TestTranslateNode(t *testing.T) {
 			},
 			subnet: "10.2.1.0/24",
 		},
+		{
+			name: "no InternalIP",
+			annotations: map[string]string{
+				endpointAnnotationKey:    "10.0.0.1:51820",
+				internalIPAnnotationKey:  "",
+				keyAnnotationKey:         "foo",
+				lastSeenAnnotationKey:    "1000000000",
+				locationAnnotationKey:    "b",
+				persistentKeepaliveKey:   "25",
+				wireGuardIPAnnotationKey: "10.4.0.1/16",
+			},
+			labels: map[string]string{
+				RegionLabelKey: "a",
+			},
+			out: &mesh.Node{
+				Endpoint:            &wireguard.Endpoint{DNSOrIP: wireguard.DNSOrIP{IP: net.ParseIP("10.0.0.1")}, Port: 51820},
+				InternalIP:          nil,
+				Key:                 []byte("foo"),
+				LastSeen:            1000000000,
+				Leader:              false,
+				Location:            "b",
+				PersistentKeepalive: 25,
+				Subnet:              &net.IPNet{IP: net.ParseIP("10.2.1.0"), Mask: net.CIDRMask(24, 32)},
+				WireGuardIP:         &net.IPNet{IP: net.ParseIP("10.4.0.1"), Mask: net.CIDRMask(16, 32)},
+			},
+			subnet: "10.2.1.0/24",
+		},
+		{
+			name: "Force no internal IP",
+			annotations: map[string]string{
+				endpointAnnotationKey:        "10.0.0.1:51820",
+				internalIPAnnotationKey:      "10.1.0.1/32",
+				forceInternalIPAnnotationKey: "",
+				keyAnnotationKey:             "foo",
+				lastSeenAnnotationKey:        "1000000000",
+				locationAnnotationKey:        "b",
+				persistentKeepaliveKey:       "25",
+				wireGuardIPAnnotationKey:     "10.4.0.1/16",
+			},
+			labels: map[string]string{
+				RegionLabelKey: "a",
+			},
+			out: &mesh.Node{
+				Endpoint:            &wireguard.Endpoint{DNSOrIP: wireguard.DNSOrIP{IP: net.ParseIP("10.0.0.1")}, Port: 51820},
+				NoInternalIP:        true,
+				InternalIP:          nil,
+				Key:                 []byte("foo"),
+				LastSeen:            1000000000,
+				Leader:              false,
+				Location:            "b",
+				PersistentKeepalive: 25,
+				Subnet:              &net.IPNet{IP: net.ParseIP("10.2.1.0"), Mask: net.CIDRMask(24, 32)},
+				WireGuardIP:         &net.IPNet{IP: net.ParseIP("10.4.0.1"), Mask: net.CIDRMask(16, 32)},
+			},
+			subnet: "10.2.1.0/24",
+		},
 	} {
 		n := &v1.Node{}
 		n.ObjectMeta.Annotations = tc.annotations
 		n.ObjectMeta.Labels = tc.labels
 		n.Spec.PodCIDR = tc.subnet
-		node := translateNode(n)
+		node := translateNode(n, RegionLabelKey)
 		if diff := pretty.Compare(node, tc.out); diff != "" {
 			t.Errorf("test case %q: got diff: %v", tc.name, diff)
 		}
@@ -240,17 +299,30 @@ func TestTranslatePeer(t *testing.T) {
 			name: "invalid endpoint ip",
 			spec: v1alpha1.PeerSpec{
 				Endpoint: &v1alpha1.PeerEndpoint{
-					IP:   "foo",
+					DNSOrIP: v1alpha1.DNSOrIP{
+						IP: "foo",
+					},
 					Port: mesh.DefaultKiloPort,
 				},
 			},
 			out: &mesh.Peer{},
 		},
 		{
-			name: "valid endpoint",
+			name: "only endpoint port",
 			spec: v1alpha1.PeerSpec{
 				Endpoint: &v1alpha1.PeerEndpoint{
-					IP:   "10.0.0.1",
+					Port: mesh.DefaultKiloPort,
+				},
+			},
+			out: &mesh.Peer{},
+		},
+		{
+			name: "valid endpoint ip",
+			spec: v1alpha1.PeerSpec{
+				Endpoint: &v1alpha1.PeerEndpoint{
+					DNSOrIP: v1alpha1.DNSOrIP{
+						IP: "10.0.0.1",
+					},
 					Port: mesh.DefaultKiloPort,
 				},
 			},
@@ -263,6 +335,25 @@ func TestTranslatePeer(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "valid endpoint DNS",
+			spec: v1alpha1.PeerSpec{
+				Endpoint: &v1alpha1.PeerEndpoint{
+					DNSOrIP: v1alpha1.DNSOrIP{
+						DNS: "example.com",
+					},
+					Port: mesh.DefaultKiloPort,
+				},
+			},
+			out: &mesh.Peer{
+				Peer: wireguard.Peer{
+					Endpoint: &wireguard.Endpoint{
+						DNSOrIP: wireguard.DNSOrIP{DNS: "example.com"},
+						Port:    mesh.DefaultKiloPort,
+					},
+				},
+			},
+		},
 		{
 			name: "empty key",
 			spec: v1alpha1.PeerSpec{

pkg/k8s/clientset/versioned/clientset.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/doc.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/fake/clientset_generated.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/fake/doc.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/fake/register.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/scheme/doc.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/scheme/register.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/doc.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/fake/doc.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/fake/fake_kilo_client.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/fake/fake_peer.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/generated_expansion.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/kilo_client.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/clientset/versioned/typed/kilo/v1alpha1/peer.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/informers/factory.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/informers/generic.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/informers/internalinterfaces/factory_interfaces.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/informers/kilo/interface.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/informers/kilo/v1alpha1/interface.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/informers/kilo/v1alpha1/peer.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/listers/kilo/v1alpha1/expansion_generated.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/k8s/listers/kilo/v1alpha1/peer.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Kilo authors
+// Copyright 2021 the Kilo authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

pkg/mesh/backend.go

@@ -0,0 +1,153 @@
+// Copyright 2019 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mesh
+
+import (
+	"net"
+	"time"
+
+	"github.com/squat/kilo/pkg/wireguard"
+)
+
+const (
+	// checkInPeriod is how often nodes should check-in.
+	checkInPeriod = 30 * time.Second
+	// DefaultKiloInterface is the default interface created and used by Kilo.
+	DefaultKiloInterface = "kilo0"
+	// DefaultKiloPort is the default UDP port Kilo uses.
+	DefaultKiloPort = 51820
+	// DefaultCNIPath is the default path to the CNI config file.
+	DefaultCNIPath = "/etc/cni/net.d/10-kilo.conflist"
+)
+
+// DefaultKiloSubnet is the default CIDR for Kilo.
+var DefaultKiloSubnet = &net.IPNet{IP: []byte{10, 4, 0, 0}, Mask: []byte{255, 255, 0, 0}}
+
+// Granularity represents the abstraction level at which the network
+// should be meshed.
+type Granularity string
+
+const (
+	// LogicalGranularity indicates that the network should create
+	// a mesh between logical locations, e.g. data-centers, but not between
+	// all nodes within a single location.
+	LogicalGranularity Granularity = "location"
+	// FullGranularity indicates that the network should create
+	// a mesh between every node.
+	FullGranularity Granularity = "full"
+)
+
+// Node represents a node in the network.
+type Node struct {
+	Endpoint     *wireguard.Endpoint
+	Key          []byte
+	NoInternalIP bool
+	InternalIP   *net.IPNet
+	// LastSeen is a Unix time for the last time
+	// the node confirmed it was live.
+	LastSeen int64
+	// Leader is a suggestion to Kilo that
+	// the node wants to lead its segment.
+	Leader              bool
+	Location            string
+	Name                string
+	PersistentKeepalive int
+	Subnet              *net.IPNet
+	WireGuardIP         *net.IPNet
+}
+
+// Ready indicates whether or not the node is ready.
+func (n *Node) Ready() bool {
+	// Nodes that are not leaders will not have WireGuardIPs, so it is not required.
+	return n != nil && n.Endpoint != nil && !(n.Endpoint.IP == nil && n.Endpoint.DNS == "") && n.Endpoint.Port != 0 && n.Key != nil && n.Subnet != nil && time.Now().Unix()-n.LastSeen < int64(checkInPeriod)*2/int64(time.Second)
+}
+
+// Peer represents a peer in the network.
+type Peer struct {
+	wireguard.Peer
+	Name string
+}
+
+// Ready indicates whether or not the peer is ready.
+// Peers can have empty endpoints because they may not have an
+// IP, for example if they are behind a NAT, and thus
+// will not declare their endpoint and instead allow it to be
+// discovered.
+func (p *Peer) Ready() bool {
+	return p != nil && p.AllowedIPs != nil && len(p.AllowedIPs) != 0 && p.PublicKey != nil
+}
+
+// EventType describes what kind of an action an event represents.
+type EventType string
+
+const (
+	// AddEvent represents an action where an item was added.
+	AddEvent EventType = "add"
+	// DeleteEvent represents an action where an item was removed.
+	DeleteEvent EventType = "delete"
+	// UpdateEvent represents an action where an item was updated.
+	UpdateEvent EventType = "update"
+)
+
+// NodeEvent represents an event concerning a node in the cluster.
+type NodeEvent struct {
+	Type EventType
+	Node *Node
+	Old  *Node
+}
+
+// PeerEvent represents an event concerning a peer in the cluster.
+type PeerEvent struct {
+	Type EventType
+	Peer *Peer
+	Old  *Peer
+}
+
+// Backend can create clients for all of the
+// primitive types that Kilo deals with, namely:
+// * nodes; and
+// * peers.
+type Backend interface {
+	Nodes() NodeBackend
+	Peers() PeerBackend
+}
+
+// NodeBackend can get nodes by name, init itself,
+// list the nodes that should be meshed,
+// set Kilo properties for a node,
+// clean up any changes applied to the backend,
+// and watch for changes to nodes.
+type NodeBackend interface {
+	CleanUp(string) error
+	Get(string) (*Node, error)
+	Init(<-chan struct{}) error
+	List() ([]*Node, error)
+	Set(string, *Node) error
+	Watch() <-chan *NodeEvent
+}
+
+// PeerBackend can get peers by name, init itself,
+// list the peers that should be in the mesh,
+// set fields for a peer,
+// clean up any changes applied to the backend,
+// and watch for changes to peers.
+type PeerBackend interface {
+	CleanUp(string) error
+	Get(string) (*Peer, error)
+	Init(<-chan struct{}) error
+	List() ([]*Peer, error)
+	Set(string, *Peer) error
+	Watch() <-chan *PeerEvent
+}

pkg/mesh/cni.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package mesh
 
 import (

pkg/mesh/discoverips.go

@@ -0,0 +1,287 @@
+// Copyright 2019 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+
+package mesh
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"sort"
+
+	"github.com/vishvananda/netlink"
+)
+
+// getIP returns a private and public IP address for the local node.
+// It selects the private IP address in the following order:
+// - private IP to which hostname resolves
+// - private IP assigned to interface of default route
+// - private IP assigned to local interface
+// - nil if no private IP was found
+// It selects the public IP address in the following order:
+// - public IP to which hostname resolves
+// - public IP assigned to interface of default route
+// - public IP assigned to local interface
+// - private IP to which hostname resolves
+// - private IP assigned to interface of default route
+// - private IP assigned to local interface
+// - if no IP was found, return nil and an error.
+func getIP(hostname string, ignoreIfaces ...int) (*net.IPNet, *net.IPNet, error) {
+	ignore := make(map[string]struct{})
+	for i := range ignoreIfaces {
+		if ignoreIfaces[i] == 0 {
+			// Only ignore valid interfaces.
+			continue
+		}
+		iface, err := net.InterfaceByIndex(ignoreIfaces[i])
+		if err != nil {
+			return nil, nil, fmt.Errorf("failed to find interface %d: %v", ignoreIfaces[i], err)
+		}
+		ips, err := ipsForInterface(iface)
+		if err != nil {
+			return nil, nil, err
+		}
+		for _, ip := range ips {
+			ignore[ip.String()] = struct{}{}
+			ignore[oneAddressCIDR(ip.IP).String()] = struct{}{}
+		}
+	}
+	var hostPriv, hostPub []*net.IPNet
+	{
+		// Check IPs to which hostname resolves first.
+		ips := ipsForHostname(hostname)
+		for _, ip := range ips {
+			ok, mask, err := assignedToInterface(ip)
+			if err != nil {
+				return nil, nil, fmt.Errorf("failed to search locally assigned addresses: %v", err)
+			}
+			if !ok {
+				continue
+			}
+			ip.Mask = mask
+			if isPublic(ip.IP) {
+				hostPub = append(hostPub, ip)
+				continue
+			}
+			hostPriv = append(hostPriv, ip)
+		}
+		sortIPs(hostPriv)
+		sortIPs(hostPub)
+	}
+
+	var defaultPriv, defaultPub []*net.IPNet
+	{
+		// Check IPs on interface for default route next.
+		iface, err := defaultInterface()
+		if err != nil {
+			return nil, nil, err
+		}
+		ips, err := ipsForInterface(iface)
+		if err != nil {
+			return nil, nil, err
+		}
+		for _, ip := range ips {
+			if isLocal(ip.IP) {
+				continue
+			}
+			if isPublic(ip.IP) {
+				defaultPub = append(defaultPub, ip)
+				continue
+			}
+			defaultPriv = append(defaultPriv, ip)
+		}
+		sortIPs(defaultPriv)
+		sortIPs(defaultPub)
+	}
+
+	var interfacePriv, interfacePub []*net.IPNet
+	{
+		// Finally look for IPs on all interfaces.
+		ips, err := ipsForAllInterfaces()
+		if err != nil {
+			return nil, nil, err
+		}
+		for _, ip := range ips {
+			if isLocal(ip.IP) {
+				continue
+			}
+			if isPublic(ip.IP) {
+				interfacePub = append(interfacePub, ip)
+				continue
+			}
+			interfacePriv = append(interfacePriv, ip)
+		}
+		sortIPs(interfacePriv)
+		sortIPs(interfacePub)
+	}
+
+	var priv, pub, tmpPriv, tmpPub []*net.IPNet
+	tmpPriv = append(tmpPriv, hostPriv...)
+	tmpPriv = append(tmpPriv, defaultPriv...)
+	tmpPriv = append(tmpPriv, interfacePriv...)
+	tmpPub = append(tmpPub, hostPub...)
+	tmpPub = append(tmpPub, defaultPub...)
+	tmpPub = append(tmpPub, interfacePub...)
+	for i := range tmpPriv {
+		if _, ok := ignore[tmpPriv[i].String()]; ok {
+			continue
+		}
+		priv = append(priv, tmpPriv[i])
+	}
+	for i := range tmpPub {
+		if _, ok := ignore[tmpPub[i].String()]; ok {
+			continue
+		}
+		pub = append(pub, tmpPub[i])
+	}
+	if len(priv) == 0 && len(pub) == 0 {
+		return nil, nil, errors.New("no valid IP was found")
+	}
+	if len(priv) == 0 {
+		// If no private IPs were found, use nil.
+		priv = append(priv, nil)
+	}
+	if len(pub) == 0 {
+		pub = priv
+	}
+	return priv[0], pub[0], nil
+}
+
+func assignedToInterface(ip *net.IPNet) (bool, net.IPMask, error) {
+	links, err := netlink.LinkList()
+	if err != nil {
+		return false, nil, fmt.Errorf("failed to list interfaces: %v", err)
+	}
+	// Sort the links for stability.
+	sort.Slice(links, func(i, j int) bool {
+		return links[i].Attrs().Name < links[j].Attrs().Name
+	})
+	for _, link := range links {
+		addrs, err := netlink.AddrList(link, netlink.FAMILY_ALL)
+		if err != nil {
+			return false, nil, fmt.Errorf("failed to list addresses for %s: %v", link.Attrs().Name, err)
+		}
+		// Sort the IPs for stability.
+		sort.Slice(addrs, func(i, j int) bool {
+			return addrs[i].String() < addrs[j].String()
+		})
+		for i := range addrs {
+			if ip.IP.Equal(addrs[i].IP) {
+				return true, addrs[i].Mask, nil
+			}
+		}
+	}
+	return false, nil, nil
+}
+
+// ipsForHostname returns a slice of IPs to which the
+// given hostname resolves.
+func ipsForHostname(hostname string) []*net.IPNet {
+	if ip := net.ParseIP(hostname); ip != nil {
+		return []*net.IPNet{oneAddressCIDR(ip)}
+	}
+	ips, err := net.LookupIP(hostname)
+	if err != nil {
+		// Most likely the hostname is not resolvable.
+		return nil
+	}
+	nets := make([]*net.IPNet, len(ips))
+	for i := range ips {
+		nets[i] = oneAddressCIDR(ips[i])
+	}
+	return nets
+}
+
+// ipsForAllInterfaces returns a slice of IPs assigned to all the
+// interfaces on the host.
+func ipsForAllInterfaces() ([]*net.IPNet, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, fmt.Errorf("failed to list interfaces: %v", err)
+	}
+	var nets []*net.IPNet
+	for _, iface := range ifaces {
+		ips, err := ipsForInterface(&iface)
+		if err != nil {
+			return nil, fmt.Errorf("failed to list addresses for %s: %v", iface.Name, err)
+		}
+		nets = append(nets, ips...)
+	}
+	return nets, nil
+}
+
+// ipsForInterface returns a slice of IPs assigned to the given interface.
+func ipsForInterface(iface *net.Interface) ([]*net.IPNet, error) {
+	link, err := netlink.LinkByIndex(iface.Index)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get link: %s", err)
+	}
+	addrs, err := netlink.AddrList(link, netlink.FAMILY_ALL)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list addresses for %s: %v", iface.Name, err)
+	}
+	var ips []*net.IPNet
+	for _, a := range addrs {
+		if a.IPNet != nil {
+			ips = append(ips, a.IPNet)
+		}
+	}
+	return ips, nil
+}
+
+// interfacesForIP returns a slice of interfaces withthe given IP.
+func interfacesForIP(ip *net.IPNet) ([]net.Interface, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, fmt.Errorf("failed to list interfaces: %v", err)
+	}
+	var interfaces []net.Interface
+	for _, iface := range ifaces {
+		ips, err := ipsForInterface(&iface)
+		if err != nil {
+			return nil, fmt.Errorf("failed to list addresses for %s: %v", iface.Name, err)
+		}
+		for i := range ips {
+			if ip.IP.Equal(ips[i].IP) {
+				interfaces = append(interfaces, iface)
+				break
+			}
+		}
+	}
+	if len(interfaces) == 0 {
+		return nil, fmt.Errorf("no interface has %s assigned", ip.String())
+	}
+	return interfaces, nil
+}
+
+// defaultInterface returns the interface for the default route of the host.
+func defaultInterface() (*net.Interface, error) {
+	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, route := range routes {
+		if route.Dst == nil || route.Dst.String() == "0.0.0.0/0" || route.Dst.String() == "::/0" {
+			if route.LinkIndex <= 0 {
+				return nil, errors.New("failed to determine interface of route")
+			}
+			return net.InterfaceByIndex(route.LinkIndex)
+		}
+	}
+
+	return nil, errors.New("failed to find default route")
+}

pkg/mesh/graph.go

@@ -27,7 +27,7 @@ import (
 func (t *Topology) Dot() (string, error) {
 	g := gographviz.NewGraph()
 	g.Name = "kilo"
-	if err := g.AddAttr("kilo", string(gographviz.Label), graphEscape(t.subnet.String())); err != nil {
+	if err := g.AddAttr("kilo", string(gographviz.Label), graphEscape((&net.IPNet{IP: t.wireGuardCIDR.IP.Mask(t.wireGuardCIDR.Mask), Mask: t.wireGuardCIDR.Mask}).String())); err != nil {
 		return "", fmt.Errorf("failed to add label to graph")
 	}
 	if err := g.AddAttr("kilo", string(gographviz.LabelLOC), "t"); err != nil {
@@ -70,7 +70,11 @@ func (t *Topology) Dot() (string, error) {
 					return "", fmt.Errorf("failed to add rank to node")
 				}
 			}
-			if err := g.Nodes.Lookup[graphEscape(s.hostnames[j])].Attrs.Add(string(gographviz.Label), nodeLabel(s.location, s.hostnames[j], s.cidrs[j], s.privateIPs[j], wg, endpoint)); err != nil {
+			var priv net.IP
+			if s.privateIPs != nil {
+				priv = s.privateIPs[j]
+			}
+			if err := g.Nodes.Lookup[graphEscape(s.hostnames[j])].Attrs.Add(string(gographviz.Label), nodeLabel(s.location, s.hostnames[j], s.cidrs[j], priv, wg, endpoint)); err != nil {
 				return "", fmt.Errorf("failed to add label to node")
 			}
 		}
@@ -155,7 +159,9 @@ func nodeLabel(location, name string, cidr *net.IPNet, priv, wgIP net.IP, endpoi
 		location,
 		name,
 		cidr.String(),
-		priv.String(),
+	}
+	if priv != nil {
+		label = append(label, priv.String())
 	}
 	if wgIP != nil {
 		label = append(label, wgIP.String())
@@ -163,9 +169,9 @@ func nodeLabel(location, name string, cidr *net.IPNet, priv, wgIP net.IP, endpoi
 	if endpoint != nil {
 		label = append(label, endpoint.String())
 	}
-	return graphEscape(strings.Join(label, "\n"))
+	return graphEscape(strings.Join(label, "\\n"))
 }
 
 func peerLabel(peer *Peer) string {
-	return graphEscape(fmt.Sprintf("%s\n%s\n", peer.Name, peer.Endpoint.String()))
+	return graphEscape(fmt.Sprintf("%s\\n%s\n", peer.Name, peer.Endpoint.String()))
 }

pkg/mesh/ip.go

@@ -15,150 +15,10 @@
 package mesh
 
 import (
-	"errors"
-	"fmt"
 	"net"
 	"sort"
-
-	"github.com/vishvananda/netlink"
 )
 
-// getIP returns a private and public IP address for the local node.
-// It selects the private IP address in the following order:
-// - private IP to which hostname resolves
-// - private IP assigned to interface of default route
-// - private IP assigned to local interface
-// - public IP to which hostname resolves
-// - public IP assigned to interface of default route
-// - public IP assigned to local interface
-// It selects the public IP address in the following order:
-// - public IP to which hostname resolves
-// - public IP assigned to interface of default route
-// - public IP assigned to local interface
-// - private IP to which hostname resolves
-// - private IP assigned to interface of default route
-// - private IP assigned to local interface
-// - if no IP was found, return nil and an error.
-func getIP(hostname string, ignoreIfaces ...int) (*net.IPNet, *net.IPNet, error) {
-	ignore := make(map[string]struct{})
-	for i := range ignoreIfaces {
-		if ignoreIfaces[i] == 0 {
-			// Only ignore valid interfaces.
-			continue
-		}
-		iface, err := net.InterfaceByIndex(ignoreIfaces[i])
-		if err != nil {
-			return nil, nil, fmt.Errorf("failed to find interface %d: %v", ignoreIfaces[i], err)
-		}
-		ips, err := ipsForInterface(iface)
-		if err != nil {
-			return nil, nil, err
-		}
-		for _, ip := range ips {
-			ignore[ip.String()] = struct{}{}
-			ignore[oneAddressCIDR(ip.IP).String()] = struct{}{}
-		}
-	}
-	var hostPriv, hostPub []*net.IPNet
-	{
-		// Check IPs to which hostname resolves first.
-		ips := ipsForHostname(hostname)
-		for _, ip := range ips {
-			ok, mask, err := assignedToInterface(ip)
-			if err != nil {
-				return nil, nil, fmt.Errorf("failed to search locally assigned addresses: %v", err)
-			}
-			if !ok {
-				continue
-			}
-			ip.Mask = mask
-			if isPublic(ip.IP) {
-				hostPub = append(hostPub, ip)
-				continue
-			}
-			hostPriv = append(hostPriv, ip)
-		}
-		sortIPs(hostPriv)
-		sortIPs(hostPub)
-	}
-
-	var defaultPriv, defaultPub []*net.IPNet
-	{
-		// Check IPs on interface for default route next.
-		iface, err := defaultInterface()
-		if err != nil {
-			return nil, nil, err
-		}
-		ips, err := ipsForInterface(iface)
-		if err != nil {
-			return nil, nil, err
-		}
-		for _, ip := range ips {
-			if isLocal(ip.IP) {
-				continue
-			}
-			if isPublic(ip.IP) {
-				defaultPub = append(defaultPub, ip)
-				continue
-			}
-			defaultPriv = append(defaultPriv, ip)
-		}
-		sortIPs(defaultPriv)
-		sortIPs(defaultPub)
-	}
-
-	var interfacePriv, interfacePub []*net.IPNet
-	{
-		// Finally look for IPs on all interfaces.
-		ips, err := ipsForAllInterfaces()
-		if err != nil {
-			return nil, nil, err
-		}
-		for _, ip := range ips {
-			if isLocal(ip.IP) {
-				continue
-			}
-			if isPublic(ip.IP) {
-				interfacePub = append(interfacePub, ip)
-				continue
-			}
-			interfacePriv = append(interfacePriv, ip)
-		}
-		sortIPs(interfacePriv)
-		sortIPs(interfacePub)
-	}
-
-	var priv, pub, tmpPriv, tmpPub []*net.IPNet
-	tmpPriv = append(tmpPriv, hostPriv...)
-	tmpPriv = append(tmpPriv, defaultPriv...)
-	tmpPriv = append(tmpPriv, interfacePriv...)
-	tmpPub = append(tmpPub, hostPub...)
-	tmpPub = append(tmpPub, defaultPub...)
-	tmpPub = append(tmpPub, interfacePub...)
-	for i := range tmpPriv {
-		if _, ok := ignore[tmpPriv[i].String()]; ok {
-			continue
-		}
-		priv = append(priv, tmpPriv[i])
-	}
-	for i := range tmpPub {
-		if _, ok := ignore[tmpPub[i].String()]; ok {
-			continue
-		}
-		pub = append(pub, tmpPub[i])
-	}
-	if len(priv) == 0 && len(pub) == 0 {
-		return nil, nil, errors.New("no valid IP was found")
-	}
-	if len(priv) == 0 {
-		priv = pub
-	}
-	if len(pub) == 0 {
-		pub = priv
-	}
-	return priv[0], pub[0], nil
-}
-
 // sortIPs sorts IPs so the result is stable.
 // It will first sort IPs by type, to prefer selecting
 // IPs of the same type, and then by value.
@@ -175,33 +35,6 @@ func sortIPs(ips []*net.IPNet) {
 	})
 }
 
-func assignedToInterface(ip *net.IPNet) (bool, net.IPMask, error) {
-	links, err := netlink.LinkList()
-	if err != nil {
-		return false, nil, fmt.Errorf("failed to list interfaces: %v", err)
-	}
-	// Sort the links for stability.
-	sort.Slice(links, func(i, j int) bool {
-		return links[i].Attrs().Name < links[j].Attrs().Name
-	})
-	for _, link := range links {
-		addrs, err := netlink.AddrList(link, netlink.FAMILY_ALL)
-		if err != nil {
-			return false, nil, fmt.Errorf("failed to list addresses for %s: %v", link.Attrs().Name, err)
-		}
-		// Sort the IPs for stability.
-		sort.Slice(addrs, func(i, j int) bool {
-			return addrs[i].String() < addrs[j].String()
-		})
-		for i := range addrs {
-			if ip.IP.Equal(addrs[i].IP) {
-				return true, addrs[i].Mask, nil
-			}
-		}
-	}
-	return false, nil, nil
-}
-
 func isLocal(ip net.IP) bool {
 	return ip.IsLoopback() || ip.IsLinkLocalMulticast() || ip.IsLinkLocalUnicast()
 }
@@ -209,12 +42,12 @@ func isLocal(ip net.IP) bool {
 func isPublic(ip net.IP) bool {
 	// Check RFC 1918 addresses.
 	if ip4 := ip.To4(); ip4 != nil {
-		switch true {
+		switch {
 		// Check for 10.0.0.0/8.
 		case ip4[0] == 10:
 			return false
 		// Check for 172.16.0.0/12.
-		case ip4[0] == 172 && ip4[1]&0xf0 == 0x01:
+		case ip4[0] == 172 && ip4[1]&0xf0 == 0x10:
 			return false
 		// Check for 192.168.0.0/16.
 		case ip4[0] == 192 && ip4[1] == 168:
@@ -225,7 +58,7 @@ func isPublic(ip net.IP) bool {
 	}
 	// Check RFC 4193 addresses.
 	if len(ip) == net.IPv6len {
-		switch true {
+		switch {
 		// Check for fd00::/8.
 		case ip[0] == 0xfd && ip[1] == 0x00:
 			return false
@@ -236,105 +69,6 @@ func isPublic(ip net.IP) bool {
 	return false
 }
 
-// ipsForHostname returns a slice of IPs to which the
-// given hostname resolves.
-func ipsForHostname(hostname string) []*net.IPNet {
-	if ip := net.ParseIP(hostname); ip != nil {
-		return []*net.IPNet{oneAddressCIDR(ip)}
-	}
-	ips, err := net.LookupIP(hostname)
-	if err != nil {
-		// Most likely the hostname is not resolvable.
-		return nil
-	}
-	nets := make([]*net.IPNet, len(ips))
-	for i := range ips {
-		nets[i] = oneAddressCIDR(ips[i])
-	}
-	return nets
-}
-
-// ipsForAllInterfaces returns a slice of IPs assigned to all the
-// interfaces on the host.
-func ipsForAllInterfaces() ([]*net.IPNet, error) {
-	ifaces, err := net.Interfaces()
-	if err != nil {
-		return nil, fmt.Errorf("failed to list interfaces: %v", err)
-	}
-	var nets []*net.IPNet
-	for _, iface := range ifaces {
-		ips, err := ipsForInterface(&iface)
-		if err != nil {
-			return nil, fmt.Errorf("failed to list addresses for %s: %v", iface.Name, err)
-		}
-		nets = append(nets, ips...)
-	}
-	return nets, nil
-}
-
-// ipsForInterface returns a slice of IPs assigned to the given interface.
-func ipsForInterface(iface *net.Interface) ([]*net.IPNet, error) {
-	link, err := netlink.LinkByIndex(iface.Index)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get link: %s", err)
-	}
-	addrs, err := netlink.AddrList(link, netlink.FAMILY_ALL)
-	if err != nil {
-		return nil, fmt.Errorf("failed to list addresses for %s: %v", iface.Name, err)
-	}
-	var ips []*net.IPNet
-	for _, a := range addrs {
-		if a.IPNet != nil {
-			ips = append(ips, a.IPNet)
-		}
-	}
-	return ips, nil
-}
-
-// interfacesForIP returns a slice of interfaces withthe given IP.
-func interfacesForIP(ip *net.IPNet) ([]net.Interface, error) {
-	ifaces, err := net.Interfaces()
-	if err != nil {
-		return nil, fmt.Errorf("failed to list interfaces: %v", err)
-	}
-	var interfaces []net.Interface
-	for _, iface := range ifaces {
-		ips, err := ipsForInterface(&iface)
-		if err != nil {
-			return nil, fmt.Errorf("failed to list addresses for %s: %v", iface.Name, err)
-		}
-		for i := range ips {
-			if ip.IP.Equal(ips[i].IP) {
-				interfaces = append(interfaces, iface)
-				break
-			}
-		}
-	}
-	if len(interfaces) == 0 {
-		return nil, fmt.Errorf("no interface has %s assigned", ip.String())
-	}
-	return interfaces, nil
-}
-
-// defaultInterface returns the interface for the default route of the host.
-func defaultInterface() (*net.Interface, error) {
-	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
-	if err != nil {
-		return nil, err
-	}
-
-	for _, route := range routes {
-		if route.Dst == nil || route.Dst.String() == "0.0.0.0/0" || route.Dst.String() == "::/0" {
-			if route.LinkIndex <= 0 {
-				return nil, errors.New("failed to determine interface of route")
-			}
-			return net.InterfaceByIndex(route.LinkIndex)
-		}
-	}
-
-	return nil, errors.New("failed to find default route")
-}
-
 type allocator struct {
 	bits    int
 	ones    int

pkg/mesh/ip_test.go

@@ -127,3 +127,46 @@ func TestSortIPs(t *testing.T) {
 		}
 	}
 }
+
+func TestIsPublic(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		ip   net.IP
+		out  bool
+	}{
+		{
+			name: "10/8",
+			ip:   net.ParseIP("10.0.0.1"),
+			out:  false,
+		},
+		{
+			name: "172.16/12",
+			ip:   net.ParseIP("172.16.0.0"),
+			out:  false,
+		},
+		{
+			name: "172.16/12 random",
+			ip:   net.ParseIP("172.24.135.46"),
+			out:  false,
+		},
+		{
+			name: "below 172.16/12",
+			ip:   net.ParseIP("172.15.255.255"),
+			out:  true,
+		},
+		{
+			name: "above 172.16/12",
+			ip:   net.ParseIP("172.160.255.255"),
+			out:  true,
+		},
+		{
+			name: "192.168/16",
+			ip:   net.ParseIP("192.168.0.0"),
+			out:  false,
+		},
+	} {
+		if isPublic(tc.ip) != tc.out {
+			t.Errorf("test case %q: expected %t, got %t", tc.name, tc.out, !tc.out)
+		}
+	}
+}

pkg/mesh/mesh.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package mesh
 
 import (
@@ -35,142 +37,15 @@ import (
 	"github.com/squat/kilo/pkg/wireguard"
 )
 
-const resyncPeriod = 30 * time.Second
-
 const (
-	// KiloPath is the directory where Kilo stores its configuration.
-	KiloPath = "/var/lib/kilo"
-	// PrivateKeyPath is the filepath where the WireGuard private key is stored.
-	PrivateKeyPath = KiloPath + "/key"
-	// ConfPath is the filepath where the WireGuard configuration is stored.
-	ConfPath = KiloPath + "/conf"
-	// DefaultKiloInterface is the default iterface created and used by Kilo.
-	DefaultKiloInterface = "kilo0"
-	// DefaultKiloPort is the default UDP port Kilo uses.
-	DefaultKiloPort = 51820
-	// DefaultCNIPath is the default path to the CNI config file.
-	DefaultCNIPath = "/etc/cni/net.d/10-kilo.conflist"
+	// kiloPath is the directory where Kilo stores its configuration.
+	kiloPath = "/var/lib/kilo"
+	// privateKeyPath is the filepath where the WireGuard private key is stored.
+	privateKeyPath = kiloPath + "/key"
+	// confPath is the filepath where the WireGuard configuration is stored.
+	confPath = kiloPath + "/conf"
 )
 
-// DefaultKiloSubnet is the default CIDR for Kilo.
-var DefaultKiloSubnet = &net.IPNet{IP: []byte{10, 4, 0, 0}, Mask: []byte{255, 255, 0, 0}}
-
-// Granularity represents the abstraction level at which the network
-// should be meshed.
-type Granularity string
-
-const (
-	// LogicalGranularity indicates that the network should create
-	// a mesh between logical locations, e.g. data-centers, but not between
-	// all nodes within a single location.
-	LogicalGranularity Granularity = "location"
-	// FullGranularity indicates that the network should create
-	// a mesh between every node.
-	FullGranularity Granularity = "full"
-)
-
-// Node represents a node in the network.
-type Node struct {
-	Endpoint   *wireguard.Endpoint
-	Key        []byte
-	InternalIP *net.IPNet
-	// LastSeen is a Unix time for the last time
-	// the node confirmed it was live.
-	LastSeen int64
-	// Leader is a suggestion to Kilo that
-	// the node wants to lead its segment.
-	Leader              bool
-	Location            string
-	Name                string
-	PersistentKeepalive int
-	Subnet              *net.IPNet
-	WireGuardIP         *net.IPNet
-}
-
-// Ready indicates whether or not the node is ready.
-func (n *Node) Ready() bool {
-	// Nodes that are not leaders will not have WireGuardIPs, so it is not required.
-	return n != nil && n.Endpoint != nil && !(n.Endpoint.IP == nil && n.Endpoint.DNS == "") && n.Endpoint.Port != 0 && n.Key != nil && n.InternalIP != nil && n.Subnet != nil && time.Now().Unix()-n.LastSeen < int64(resyncPeriod)*2/int64(time.Second)
-}
-
-// Peer represents a peer in the network.
-type Peer struct {
-	wireguard.Peer
-	Name string
-}
-
-// Ready indicates whether or not the peer is ready.
-// Peers can have empty endpoints because they may not have an
-// IP, for example if they are behind a NAT, and thus
-// will not declare their endpoint and instead allow it to be
-// discovered.
-func (p *Peer) Ready() bool {
-	return p != nil && p.AllowedIPs != nil && len(p.AllowedIPs) != 0 && p.PublicKey != nil
-}
-
-// EventType describes what kind of an action an event represents.
-type EventType string
-
-const (
-	// AddEvent represents an action where an item was added.
-	AddEvent EventType = "add"
-	// DeleteEvent represents an action where an item was removed.
-	DeleteEvent EventType = "delete"
-	// UpdateEvent represents an action where an item was updated.
-	UpdateEvent EventType = "update"
-)
-
-// NodeEvent represents an event concerning a node in the cluster.
-type NodeEvent struct {
-	Type EventType
-	Node *Node
-	Old  *Node
-}
-
-// PeerEvent represents an event concerning a peer in the cluster.
-type PeerEvent struct {
-	Type EventType
-	Peer *Peer
-	Old  *Peer
-}
-
-// Backend can create clients for all of the
-// primitive types that Kilo deals with, namely:
-// * nodes; and
-// * peers.
-type Backend interface {
-	Nodes() NodeBackend
-	Peers() PeerBackend
-}
-
-// NodeBackend can get nodes by name, init itself,
-// list the nodes that should be meshed,
-// set Kilo properties for a node,
-// clean up any changes applied to the backend,
-// and watch for changes to nodes.
-type NodeBackend interface {
-	CleanUp(string) error
-	Get(string) (*Node, error)
-	Init(<-chan struct{}) error
-	List() ([]*Node, error)
-	Set(string, *Node) error
-	Watch() <-chan *NodeEvent
-}
-
-// PeerBackend can get peers by name, init itself,
-// list the peers that should be in the mesh,
-// set fields for a peer,
-// clean up any changes applied to the backend,
-// and watch for changes to peers.
-type PeerBackend interface {
-	CleanUp(string) error
-	Get(string) (*Peer, error)
-	Init(<-chan struct{}) error
-	List() ([]*Peer, error)
-	Set(string, *Peer) error
-	Watch() <-chan *PeerEvent
-}
-
 // Mesh is able to create Kilo network meshes.
 type Mesh struct {
 	Backend
@@ -190,13 +65,14 @@ type Mesh struct {
 	priv         []byte
 	privIface    int
 	pub          []byte
+	resyncPeriod time.Duration
 	stop         chan struct{}
 	subnet       *net.IPNet
 	table        *route.Table
 	wireGuardIP  *net.IPNet
 
 	// nodes and peers are mutable fields in the struct
-	// and needs to be guarded.
+	// and need to be guarded.
 	nodes map[string]*Node
 	peers map[string]*Peer
 	mu    sync.Mutex
@@ -210,11 +86,11 @@ type Mesh struct {
 }
 
 // New returns a new Mesh instance.
-func New(backend Backend, enc encapsulation.Encapsulator, granularity Granularity, hostname string, port uint32, subnet *net.IPNet, local, cni bool, cniPath, iface string, cleanUpIface bool, logger log.Logger) (*Mesh, error) {
-	if err := os.MkdirAll(KiloPath, 0700); err != nil {
+func New(backend Backend, enc encapsulation.Encapsulator, granularity Granularity, hostname string, port uint32, subnet *net.IPNet, local, cni bool, cniPath, iface string, cleanUpIface bool, createIface bool, resyncPeriod time.Duration, logger log.Logger) (*Mesh, error) {
+	if err := os.MkdirAll(kiloPath, 0700); err != nil {
 		return nil, fmt.Errorf("failed to create directory to store configuration: %v", err)
 	}
-	private, err := ioutil.ReadFile(PrivateKeyPath)
+	private, err := ioutil.ReadFile(privateKeyPath)
 	private = bytes.Trim(private, "\n")
 	if err != nil {
 		level.Warn(logger).Log("msg", "no private key found on disk; generating one now")
@@ -226,34 +102,49 @@ func New(backend Backend, enc encapsulation.Encapsulator, granularity Granularit
 	if err != nil {
 		return nil, err
 	}
-	if err := ioutil.WriteFile(PrivateKeyPath, private, 0600); err != nil {
+	if err := ioutil.WriteFile(privateKeyPath, private, 0600); err != nil {
 		return nil, fmt.Errorf("failed to write private key to disk: %v", err)
 	}
 	cniIndex, err := cniDeviceIndex()
 	if err != nil {
 		return nil, fmt.Errorf("failed to query netlink for CNI device: %v", err)
 	}
-	privateIP, publicIP, err := getIP(hostname, enc.Index(), cniIndex)
+	var kiloIface int
+	if createIface {
+		kiloIface, _, err = wireguard.New(iface)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create WireGuard interface: %v", err)
+		}
+	} else {
+		link, err := netlink.LinkByName(iface)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get interface index: %v", err)
+		}
+		kiloIface = link.Attrs().Index
+	}
+	privateIP, publicIP, err := getIP(hostname, kiloIface, enc.Index(), cniIndex)
 	if err != nil {
 		return nil, fmt.Errorf("failed to find public IP: %v", err)
 	}
-	ifaces, err := interfacesForIP(privateIP)
-	if err != nil {
-		return nil, fmt.Errorf("failed to find interface for private IP: %v", err)
-	}
-	privIface := ifaces[0].Index
-	kiloIface, _, err := wireguard.New(iface)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create WireGuard interface: %v", err)
-	}
-	if enc.Strategy() != encapsulation.Never {
-		if err := enc.Init(privIface); err != nil {
-			return nil, fmt.Errorf("failed to initialize encapsulator: %v", err)
+	var privIface int
+	if privateIP != nil {
+		ifaces, err := interfacesForIP(privateIP)
+		if err != nil {
+			return nil, fmt.Errorf("failed to find interface for private IP: %v", err)
 		}
+		privIface = ifaces[0].Index
+		if enc.Strategy() != encapsulation.Never {
+			if err := enc.Init(privIface); err != nil {
+				return nil, fmt.Errorf("failed to initialize encapsulator: %v", err)
+			}
+		}
+		level.Debug(logger).Log("msg", fmt.Sprintf("using %s as the private IP address", privateIP.String()))
+	} else {
+		enc = encapsulation.Noop(enc.Strategy())
+		level.Debug(logger).Log("msg", "running without a private IP address")
 	}
-	level.Debug(logger).Log("msg", fmt.Sprintf("using %s as the private IP address", privateIP.String()))
 	level.Debug(logger).Log("msg", fmt.Sprintf("using %s as the public IP address", publicIP.String()))
-	ipTables, err := iptables.New()
+	ipTables, err := iptables.New(iptables.WithLogger(log.With(logger, "component", "iptables")), iptables.WithResyncPeriod(resyncPeriod))
 	if err != nil {
 		return nil, fmt.Errorf("failed to IP tables controller: %v", err)
 	}
@@ -275,6 +166,7 @@ func New(backend Backend, enc encapsulation.Encapsulator, granularity Granularit
 		priv:         private,
 		privIface:    privIface,
 		pub:          public,
+		resyncPeriod: resyncPeriod,
 		local:        local,
 		stop:         make(chan struct{}),
 		subnet:       subnet,
@@ -344,7 +236,8 @@ func (m *Mesh) Run() error {
 		}
 	}()
 	defer m.cleanUp()
-	t := time.NewTimer(resyncPeriod)
+	resync := time.NewTimer(m.resyncPeriod)
+	checkIn := time.NewTimer(checkInPeriod)
 	nw := m.Nodes().Watch()
 	pw := m.Peers().Watch()
 	var ne *NodeEvent
@@ -355,13 +248,15 @@ func (m *Mesh) Run() error {
 			m.syncNodes(ne)
 		case pe = <-pw:
 			m.syncPeers(pe)
-		case <-t.C:
+		case <-checkIn.C:
 			m.checkIn()
+			checkIn.Reset(checkInPeriod)
+		case <-resync.C:
 			if m.cni {
 				m.updateCNIConfig()
 			}
 			m.applyTopology()
-			t.Reset(resyncPeriod)
+			resync.Reset(m.resyncPeriod)
 		case <-m.stop:
 			return nil
 		}
@@ -476,7 +371,7 @@ func (m *Mesh) handleLocal(n *Node) {
 	if n.Endpoint == nil || (n.Endpoint.DNS == "" && n.Endpoint.IP == nil) {
 		n.Endpoint = &wireguard.Endpoint{DNSOrIP: wireguard.DNSOrIP{IP: m.externalIP.IP}, Port: m.port}
 	}
-	if n.InternalIP == nil {
+	if n.InternalIP == nil && !n.NoInternalIP {
 		n.InternalIP = m.internalIP
 	}
 	// Compare the given node to the calculated local node.
@@ -485,6 +380,7 @@ func (m *Mesh) handleLocal(n *Node) {
 	local := &Node{
 		Endpoint:            n.Endpoint,
 		Key:                 m.pub,
+		NoInternalIP:        n.NoInternalIP,
 		InternalIP:          n.InternalIP,
 		LastSeen:            time.Now().Unix(),
 		Leader:              n.Leader,
@@ -581,7 +477,11 @@ func (m *Mesh) applyTopology() {
 		return
 	}
 	// Update the node's WireGuard IP.
-	m.wireGuardIP = t.wireGuardCIDR
+	if t.leader {
+		m.wireGuardIP = t.wireGuardCIDR
+	} else {
+		m.wireGuardIP = nil
+	}
 	conf := t.Conf()
 	buf, err := conf.Bytes()
 	if err != nil {
@@ -589,21 +489,21 @@ func (m *Mesh) applyTopology() {
 		m.errorCounter.WithLabelValues("apply").Inc()
 		return
 	}
-	if err := ioutil.WriteFile(ConfPath, buf, 0600); err != nil {
+	if err := ioutil.WriteFile(confPath, buf, 0600); err != nil {
 		level.Error(m.logger).Log("error", err)
 		m.errorCounter.WithLabelValues("apply").Inc()
 		return
 	}
-	var ipRules []iptables.Rule
-	if m.cni {
-		ipRules = append(ipRules, t.Rules(m.cni)...)
-	}
+	ipRules := t.Rules(m.cni)
 	// If we are handling local routes, ensure the local
 	// tunnel has an IP address and IPIP traffic is allowed.
 	if m.enc.Strategy() != encapsulation.Never && m.local {
 		var cidrs []*net.IPNet
 		for _, s := range t.segments {
-			if s.location == nodes[m.hostname].Location {
+			// If the location prefix is not logicalLocation, but nodeLocation,
+			// we don't need to set any extra rules for encapsulation anyways
+			// because traffic will go over WireGuard.
+			if s.location == logicalLocationPrefix+nodes[m.hostname].Location {
 				for i := range s.privateIPs {
 					cidrs = append(cidrs, oneAddressCIDR(s.privateIPs[i]))
 				}
@@ -636,7 +536,7 @@ func (m *Mesh) applyTopology() {
 		equal := conf.Equal(oldConf)
 		if !equal {
 			level.Info(m.logger).Log("msg", "WireGuard configurations are different")
-			if err := wireguard.SetConf(link.Attrs().Name, ConfPath); err != nil {
+			if err := wireguard.SetConf(link.Attrs().Name, confPath); err != nil {
 				level.Error(m.logger).Log("error", err)
 				m.errorCounter.WithLabelValues("apply").Inc()
 				return
@@ -691,7 +591,7 @@ func (m *Mesh) cleanUp() {
 		level.Error(m.logger).Log("error", fmt.Sprintf("failed to clean up routes: %v", err))
 		m.errorCounter.WithLabelValues("cleanUp").Inc()
 	}
-	if err := os.Remove(ConfPath); err != nil {
+	if err := os.Remove(confPath); err != nil {
 		level.Error(m.logger).Log("error", fmt.Sprintf("failed to delete configuration file: %v", err))
 		m.errorCounter.WithLabelValues("cleanUp").Inc()
 	}
@@ -770,7 +670,7 @@ func isSelf(hostname string, node *Node) bool {
 }
 
 func nodesAreEqual(a, b *Node) bool {
-	if !(a != nil) == (b != nil) {
+	if (a != nil) != (b != nil) {
 		return false
 	}
 	if a == b {

pkg/mesh/routes.go

@@ -0,0 +1,256 @@
+// Copyright 2019 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+
+package mesh
+
+import (
+	"net"
+
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+
+	"github.com/squat/kilo/pkg/encapsulation"
+	"github.com/squat/kilo/pkg/iptables"
+)
+
+const kiloTableIndex = 1107
+
+// Routes generates a slice of routes for a given Topology.
+func (t *Topology) Routes(kiloIfaceName string, kiloIface, privIface, tunlIface int, local bool, enc encapsulation.Encapsulator) ([]*netlink.Route, []*netlink.Rule) {
+	var routes []*netlink.Route
+	var rules []*netlink.Rule
+	if !t.leader {
+		// Find the GW for this segment.
+		// This will be the an IP of the leader.
+		// In an IPIP encapsulated mesh it is the leader's private IP.
+		var gw net.IP
+		for _, segment := range t.segments {
+			if segment.location == t.location {
+				gw = enc.Gw(segment.endpoint.IP, segment.privateIPs[segment.leader], segment.cidrs[segment.leader])
+				break
+			}
+		}
+		for _, segment := range t.segments {
+			// First, add a route to the WireGuard IP of the segment.
+			routes = append(routes, encapsulateRoute(&netlink.Route{
+				Dst:       oneAddressCIDR(segment.wireGuardIP),
+				Flags:     int(netlink.FLAG_ONLINK),
+				Gw:        gw,
+				LinkIndex: privIface,
+				Protocol:  unix.RTPROT_STATIC,
+			}, enc.Strategy(), t.privateIP, tunlIface))
+			// Add routes for the current segment if local is true.
+			if segment.location == t.location {
+				if local {
+					for i := range segment.cidrs {
+						// Don't add routes for the local node.
+						if segment.privateIPs[i].Equal(t.privateIP.IP) {
+							continue
+						}
+						routes = append(routes, encapsulateRoute(&netlink.Route{
+							Dst:       segment.cidrs[i],
+							Flags:     int(netlink.FLAG_ONLINK),
+							Gw:        segment.privateIPs[i],
+							LinkIndex: privIface,
+							Protocol:  unix.RTPROT_STATIC,
+						}, enc.Strategy(), t.privateIP, tunlIface))
+						// Encapsulate packets from the host's Pod subnet headed
+						// to private IPs.
+						if enc.Strategy() == encapsulation.Always || (enc.Strategy() == encapsulation.CrossSubnet && !t.privateIP.Contains(segment.privateIPs[i])) {
+							routes = append(routes, &netlink.Route{
+								Dst:       oneAddressCIDR(segment.privateIPs[i]),
+								Flags:     int(netlink.FLAG_ONLINK),
+								Gw:        segment.privateIPs[i],
+								LinkIndex: tunlIface,
+								Protocol:  unix.RTPROT_STATIC,
+								Table:     kiloTableIndex,
+							})
+							rules = append(rules, defaultRule(&netlink.Rule{
+								Src:   t.subnet,
+								Dst:   oneAddressCIDR(segment.privateIPs[i]),
+								Table: kiloTableIndex,
+							}))
+						}
+					}
+				}
+				continue
+			}
+			for i := range segment.cidrs {
+				// Add routes to the Pod CIDRs of nodes in other segments.
+				routes = append(routes, encapsulateRoute(&netlink.Route{
+					Dst:       segment.cidrs[i],
+					Flags:     int(netlink.FLAG_ONLINK),
+					Gw:        gw,
+					LinkIndex: privIface,
+					Protocol:  unix.RTPROT_STATIC,
+				}, enc.Strategy(), t.privateIP, tunlIface))
+			}
+			for i := range segment.privateIPs {
+				// Add routes to the private IPs of nodes in other segments.
+				routes = append(routes, encapsulateRoute(&netlink.Route{
+					Dst:       oneAddressCIDR(segment.privateIPs[i]),
+					Flags:     int(netlink.FLAG_ONLINK),
+					Gw:        gw,
+					LinkIndex: privIface,
+					Protocol:  unix.RTPROT_STATIC,
+				}, enc.Strategy(), t.privateIP, tunlIface))
+			}
+		}
+		// Add routes for the allowed IPs of peers.
+		for _, peer := range t.peers {
+			for i := range peer.AllowedIPs {
+				routes = append(routes, encapsulateRoute(&netlink.Route{
+					Dst:       peer.AllowedIPs[i],
+					Flags:     int(netlink.FLAG_ONLINK),
+					Gw:        gw,
+					LinkIndex: privIface,
+					Protocol:  unix.RTPROT_STATIC,
+				}, enc.Strategy(), t.privateIP, tunlIface))
+			}
+		}
+		return routes, rules
+	}
+	for _, segment := range t.segments {
+		// Add routes for the current segment if local is true.
+		if segment.location == t.location {
+			// If the local node does not have a private IP address,
+			// then skip adding routes, because the node is in its own location.
+			if local && t.privateIP != nil {
+				for i := range segment.cidrs {
+					// Don't add routes for the local node.
+					if segment.privateIPs[i].Equal(t.privateIP.IP) {
+						continue
+					}
+					routes = append(routes, encapsulateRoute(&netlink.Route{
+						Dst:       segment.cidrs[i],
+						Flags:     int(netlink.FLAG_ONLINK),
+						Gw:        segment.privateIPs[i],
+						LinkIndex: privIface,
+						Protocol:  unix.RTPROT_STATIC,
+					}, enc.Strategy(), t.privateIP, tunlIface))
+					// Encapsulate packets from the host's Pod subnet headed
+					// to private IPs.
+					if enc.Strategy() == encapsulation.Always || (enc.Strategy() == encapsulation.CrossSubnet && !t.privateIP.Contains(segment.privateIPs[i])) {
+						routes = append(routes, &netlink.Route{
+							Dst:       oneAddressCIDR(segment.privateIPs[i]),
+							Flags:     int(netlink.FLAG_ONLINK),
+							Gw:        segment.privateIPs[i],
+							LinkIndex: tunlIface,
+							Protocol:  unix.RTPROT_STATIC,
+							Table:     kiloTableIndex,
+						})
+						rules = append(rules, defaultRule(&netlink.Rule{
+							Src:   t.subnet,
+							Dst:   oneAddressCIDR(segment.privateIPs[i]),
+							Table: kiloTableIndex,
+						}))
+						// Also encapsulate packets from the Kilo interface
+						// headed to private IPs.
+						rules = append(rules, defaultRule(&netlink.Rule{
+							Dst:     oneAddressCIDR(segment.privateIPs[i]),
+							Table:   kiloTableIndex,
+							IifName: kiloIfaceName,
+						}))
+					}
+				}
+			}
+			// Continuing here prevents leaders form adding routes via WireGuard to
+			// nodes in their own location.
+			continue
+		}
+		for i := range segment.cidrs {
+			// Add routes to the Pod CIDRs of nodes in other segments.
+			routes = append(routes, &netlink.Route{
+				Dst:       segment.cidrs[i],
+				Flags:     int(netlink.FLAG_ONLINK),
+				Gw:        segment.wireGuardIP,
+				LinkIndex: kiloIface,
+				Protocol:  unix.RTPROT_STATIC,
+			})
+			// Don't add routes through Kilo if the private IP
+			// equals the external IP. This means that the node
+			// is only accessible through an external IP and we
+			// cannot encapsulate traffic to an IP through the IP.
+			if segment.privateIPs == nil || segment.privateIPs[i].Equal(segment.endpoint.IP) {
+				continue
+			}
+			// Add routes to the private IPs of nodes in other segments.
+			// Number of CIDRs and private IPs always match so
+			// we can reuse the loop.
+			routes = append(routes, &netlink.Route{
+				Dst:       oneAddressCIDR(segment.privateIPs[i]),
+				Flags:     int(netlink.FLAG_ONLINK),
+				Gw:        segment.wireGuardIP,
+				LinkIndex: kiloIface,
+				Protocol:  unix.RTPROT_STATIC,
+			})
+		}
+	}
+	// Add routes for the allowed IPs of peers.
+	for _, peer := range t.peers {
+		for i := range peer.AllowedIPs {
+			routes = append(routes, &netlink.Route{
+				Dst:       peer.AllowedIPs[i],
+				LinkIndex: kiloIface,
+				Protocol:  unix.RTPROT_STATIC,
+			})
+		}
+	}
+	return routes, rules
+}
+
+func encapsulateRoute(route *netlink.Route, encapsulate encapsulation.Strategy, subnet *net.IPNet, tunlIface int) *netlink.Route {
+	if encapsulate == encapsulation.Always || (encapsulate == encapsulation.CrossSubnet && !subnet.Contains(route.Gw)) {
+		route.LinkIndex = tunlIface
+	}
+	return route
+}
+
+// Rules returns the iptables rules required by the local node.
+func (t *Topology) Rules(cni bool) []iptables.Rule {
+	var rules []iptables.Rule
+	rules = append(rules, iptables.NewIPv4Chain("nat", "KILO-NAT"))
+	rules = append(rules, iptables.NewIPv6Chain("nat", "KILO-NAT"))
+	if cni {
+		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "nat", "POSTROUTING", "-s", t.subnet.String(), "-m", "comment", "--comment", "Kilo: jump to KILO-NAT chain", "-j", "KILO-NAT"))
+	}
+	for _, s := range t.segments {
+		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(s.wireGuardIP)), "nat", "KILO-NAT", "-d", oneAddressCIDR(s.wireGuardIP).String(), "-m", "comment", "--comment", "Kilo: do not NAT packets destined for WireGuared IPs", "-j", "RETURN"))
+		for _, aip := range s.allowedIPs {
+			rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(aip.IP)), "nat", "KILO-NAT", "-d", aip.String(), "-m", "comment", "--comment", "Kilo: do not NAT packets destined for known IPs", "-j", "RETURN"))
+		}
+	}
+	for _, p := range t.peers {
+		for _, aip := range p.AllowedIPs {
+			rules = append(rules,
+				iptables.NewRule(iptables.GetProtocol(len(aip.IP)), "nat", "POSTROUTING", "-s", aip.String(), "-m", "comment", "--comment", "Kilo: jump to NAT chain", "-j", "KILO-NAT"),
+				iptables.NewRule(iptables.GetProtocol(len(aip.IP)), "nat", "KILO-NAT", "-d", aip.String(), "-m", "comment", "--comment", "Kilo: do not NAT packets destined for peers", "-j", "RETURN"),
+			)
+		}
+	}
+	rules = append(rules, iptables.NewIPv4Rule("nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: NAT remaining packets", "-j", "MASQUERADE"))
+	rules = append(rules, iptables.NewIPv6Rule("nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: NAT remaining packets", "-j", "MASQUERADE"))
+	return rules
+}
+
+func defaultRule(rule *netlink.Rule) *netlink.Rule {
+	base := netlink.NewRule()
+	base.Src = rule.Src
+	base.Dst = rule.Dst
+	base.IifName = rule.IifName
+	base.Table = rule.Table
+	return base
+}

pkg/mesh/topology.go

@@ -19,14 +19,13 @@ import (
 	"net"
 	"sort"
 
-	"github.com/squat/kilo/pkg/encapsulation"
-	"github.com/squat/kilo/pkg/iptables"
 	"github.com/squat/kilo/pkg/wireguard"
-	"github.com/vishvananda/netlink"
-	"golang.org/x/sys/unix"
 )
 
-const kiloTableIndex = 1107
+const (
+	logicalLocationPrefix = "location:"
+	nodeLocationPrefix    = "node:"
+)
 
 // Topology represents the logical structure of the overlay network.
 type Topology struct {
@@ -51,8 +50,10 @@ type Topology struct {
 	// subnet is the Pod subnet of the local node.
 	subnet *net.IPNet
 	// wireGuardCIDR is the allocated CIDR of the WireGuard
-	// interface of the local node. If the local node is not
-	// the leader, then it is nil.
+	// interface of the local node within the Kilo subnet.
+	// If the local node is not the leader of a location, then
+	// the IP is the 0th address in the subnet, i.e. the CIDR
+	// is equal to the Kilo subnet.
 	wireGuardCIDR *net.IPNet
 }
 
@@ -83,21 +84,29 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 		var location string
 		switch granularity {
 		case LogicalGranularity:
-			location = node.Location
+			location = logicalLocationPrefix + node.Location
+			// Put node in a different location, if no private
+			// IP was found.
+			if node.InternalIP == nil {
+				location = nodeLocationPrefix + node.Name
+			}
 		case FullGranularity:
-			location = node.Name
+			location = nodeLocationPrefix + node.Name
 		}
 		topoMap[location] = append(topoMap[location], node)
 	}
 	var localLocation string
 	switch granularity {
 	case LogicalGranularity:
-		localLocation = nodes[hostname].Location
+		localLocation = logicalLocationPrefix + nodes[hostname].Location
+		if nodes[hostname].InternalIP == nil {
+			localLocation = nodeLocationPrefix + hostname
+		}
 	case FullGranularity:
-		localLocation = hostname
+		localLocation = nodeLocationPrefix + hostname
 	}
 
-	t := Topology{key: key, port: port, hostname: hostname, location: localLocation, persistentKeepalive: persistentKeepalive, privateIP: nodes[hostname].InternalIP, subnet: nodes[hostname].Subnet}
+	t := Topology{key: key, port: port, hostname: hostname, location: localLocation, persistentKeepalive: persistentKeepalive, privateIP: nodes[hostname].InternalIP, subnet: nodes[hostname].Subnet, wireGuardCIDR: subnet}
 	for location := range topoMap {
 		// Sort the location so the result is stable.
 		sort.Slice(topoMap[location], func(i, j int) bool {
@@ -116,10 +125,13 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 			// - the node's allocated subnet
 			// - the node's WireGuard IP
 			// - the node's internal IP
-			allowedIPs = append(allowedIPs, node.Subnet, oneAddressCIDR(node.InternalIP.IP))
+			allowedIPs = append(allowedIPs, node.Subnet)
+			if node.InternalIP != nil {
+				allowedIPs = append(allowedIPs, oneAddressCIDR(node.InternalIP.IP))
+				privateIPs = append(privateIPs, node.InternalIP.IP)
+			}
 			cidrs = append(cidrs, node.Subnet)
 			hostnames = append(hostnames, node.Name)
-			privateIPs = append(privateIPs, node.InternalIP.IP)
 		}
 		t.segments = append(t.segments, &segment{
 			allowedIPs: allowedIPs,
@@ -164,193 +176,6 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 	return &t, nil
 }
 
-// Routes generates a slice of routes for a given Topology.
-func (t *Topology) Routes(kiloIfaceName string, kiloIface, privIface, tunlIface int, local bool, enc encapsulation.Encapsulator) ([]*netlink.Route, []*netlink.Rule) {
-	var routes []*netlink.Route
-	var rules []*netlink.Rule
-	if !t.leader {
-		// Find the GW for this segment.
-		// This will be the an IP of the leader.
-		// In an IPIP encapsulated mesh it is the leader's private IP.
-		var gw net.IP
-		for _, segment := range t.segments {
-			if segment.location == t.location {
-				gw = enc.Gw(segment.endpoint.IP, segment.privateIPs[segment.leader], segment.cidrs[segment.leader])
-				break
-			}
-		}
-		for _, segment := range t.segments {
-			// First, add a route to the WireGuard IP of the segment.
-			routes = append(routes, encapsulateRoute(&netlink.Route{
-				Dst:       oneAddressCIDR(segment.wireGuardIP),
-				Flags:     int(netlink.FLAG_ONLINK),
-				Gw:        gw,
-				LinkIndex: privIface,
-				Protocol:  unix.RTPROT_STATIC,
-			}, enc.Strategy(), t.privateIP, tunlIface))
-			// Add routes for the current segment if local is true.
-			if segment.location == t.location {
-				if local {
-					for i := range segment.cidrs {
-						// Don't add routes for the local node.
-						if segment.privateIPs[i].Equal(t.privateIP.IP) {
-							continue
-						}
-						routes = append(routes, encapsulateRoute(&netlink.Route{
-							Dst:       segment.cidrs[i],
-							Flags:     int(netlink.FLAG_ONLINK),
-							Gw:        segment.privateIPs[i],
-							LinkIndex: privIface,
-							Protocol:  unix.RTPROT_STATIC,
-						}, enc.Strategy(), t.privateIP, tunlIface))
-						// Encapsulate packets from the host's Pod subnet headed
-						// to private IPs.
-						if enc.Strategy() == encapsulation.Always || (enc.Strategy() == encapsulation.CrossSubnet && !t.privateIP.Contains(segment.privateIPs[i])) {
-							routes = append(routes, &netlink.Route{
-								Dst:       oneAddressCIDR(segment.privateIPs[i]),
-								Flags:     int(netlink.FLAG_ONLINK),
-								Gw:        segment.privateIPs[i],
-								LinkIndex: tunlIface,
-								Protocol:  unix.RTPROT_STATIC,
-								Table:     kiloTableIndex,
-							})
-							rules = append(rules, defaultRule(&netlink.Rule{
-								Src:   t.subnet,
-								Dst:   oneAddressCIDR(segment.privateIPs[i]),
-								Table: kiloTableIndex,
-							}))
-						}
-					}
-				}
-				continue
-			}
-			for i := range segment.cidrs {
-				// Add routes to the Pod CIDRs of nodes in other segments.
-				routes = append(routes, encapsulateRoute(&netlink.Route{
-					Dst:       segment.cidrs[i],
-					Flags:     int(netlink.FLAG_ONLINK),
-					Gw:        gw,
-					LinkIndex: privIface,
-					Protocol:  unix.RTPROT_STATIC,
-				}, enc.Strategy(), t.privateIP, tunlIface))
-				// Add routes to the private IPs of nodes in other segments.
-				// Number of CIDRs and private IPs always match so
-				// we can reuse the loop.
-				routes = append(routes, encapsulateRoute(&netlink.Route{
-					Dst:       oneAddressCIDR(segment.privateIPs[i]),
-					Flags:     int(netlink.FLAG_ONLINK),
-					Gw:        gw,
-					LinkIndex: privIface,
-					Protocol:  unix.RTPROT_STATIC,
-				}, enc.Strategy(), t.privateIP, tunlIface))
-			}
-		}
-		// Add routes for the allowed IPs of peers.
-		for _, peer := range t.peers {
-			for i := range peer.AllowedIPs {
-				routes = append(routes, encapsulateRoute(&netlink.Route{
-					Dst:       peer.AllowedIPs[i],
-					Flags:     int(netlink.FLAG_ONLINK),
-					Gw:        gw,
-					LinkIndex: privIface,
-					Protocol:  unix.RTPROT_STATIC,
-				}, enc.Strategy(), t.privateIP, tunlIface))
-			}
-		}
-		return routes, rules
-	}
-	for _, segment := range t.segments {
-		// Add routes for the current segment if local is true.
-		if segment.location == t.location {
-			if local {
-				for i := range segment.cidrs {
-					// Don't add routes for the local node.
-					if segment.privateIPs[i].Equal(t.privateIP.IP) {
-						continue
-					}
-					routes = append(routes, encapsulateRoute(&netlink.Route{
-						Dst:       segment.cidrs[i],
-						Flags:     int(netlink.FLAG_ONLINK),
-						Gw:        segment.privateIPs[i],
-						LinkIndex: privIface,
-						Protocol:  unix.RTPROT_STATIC,
-					}, enc.Strategy(), t.privateIP, tunlIface))
-					// Encapsulate packets from the host's Pod subnet headed
-					// to private IPs.
-					if enc.Strategy() == encapsulation.Always || (enc.Strategy() == encapsulation.CrossSubnet && !t.privateIP.Contains(segment.privateIPs[i])) {
-						routes = append(routes, &netlink.Route{
-							Dst:       oneAddressCIDR(segment.privateIPs[i]),
-							Flags:     int(netlink.FLAG_ONLINK),
-							Gw:        segment.privateIPs[i],
-							LinkIndex: tunlIface,
-							Protocol:  unix.RTPROT_STATIC,
-							Table:     kiloTableIndex,
-						})
-						rules = append(rules, defaultRule(&netlink.Rule{
-							Src:   t.subnet,
-							Dst:   oneAddressCIDR(segment.privateIPs[i]),
-							Table: kiloTableIndex,
-						}))
-						// Also encapsulate packets from the Kilo interface
-						// headed to private IPs.
-						rules = append(rules, defaultRule(&netlink.Rule{
-							Dst:     oneAddressCIDR(segment.privateIPs[i]),
-							Table:   kiloTableIndex,
-							IifName: kiloIfaceName,
-						}))
-					}
-				}
-			}
-			continue
-		}
-		for i := range segment.cidrs {
-			// Add routes to the Pod CIDRs of nodes in other segments.
-			routes = append(routes, &netlink.Route{
-				Dst:       segment.cidrs[i],
-				Flags:     int(netlink.FLAG_ONLINK),
-				Gw:        segment.wireGuardIP,
-				LinkIndex: kiloIface,
-				Protocol:  unix.RTPROT_STATIC,
-			})
-			// Don't add routes through Kilo if the private IP
-			// equals the external IP. This means that the node
-			// is only accessible through an external IP and we
-			// cannot encapsulate traffic to an IP through the IP.
-			if segment.privateIPs[i].Equal(segment.endpoint.IP) {
-				continue
-			}
-			// Add routes to the private IPs of nodes in other segments.
-			// Number of CIDRs and private IPs always match so
-			// we can reuse the loop.
-			routes = append(routes, &netlink.Route{
-				Dst:       oneAddressCIDR(segment.privateIPs[i]),
-				Flags:     int(netlink.FLAG_ONLINK),
-				Gw:        segment.wireGuardIP,
-				LinkIndex: kiloIface,
-				Protocol:  unix.RTPROT_STATIC,
-			})
-		}
-	}
-	// Add routes for the allowed IPs of peers.
-	for _, peer := range t.peers {
-		for i := range peer.AllowedIPs {
-			routes = append(routes, &netlink.Route{
-				Dst:       peer.AllowedIPs[i],
-				LinkIndex: kiloIface,
-				Protocol:  unix.RTPROT_STATIC,
-			})
-		}
-	}
-	return routes, rules
-}
-
-func encapsulateRoute(route *netlink.Route, encapsulate encapsulation.Strategy, subnet *net.IPNet, tunlIface int) *netlink.Route {
-	if encapsulate == encapsulation.Always || (encapsulate == encapsulation.CrossSubnet && !subnet.Contains(route.Gw)) {
-		route.LinkIndex = tunlIface
-	}
-	return route
-}
-
 // Conf generates a WireGuard configuration file for a given Topology.
 func (t *Topology) Conf() *wireguard.Conf {
 	c := &wireguard.Conf{
@@ -437,33 +262,6 @@ func (t *Topology) PeerConf(name string) *wireguard.Conf {
 	return c
 }
 
-// Rules returns the iptables rules required by the local node.
-func (t *Topology) Rules(cni bool) []iptables.Rule {
-	var rules []iptables.Rule
-	rules = append(rules, iptables.NewIPv4Chain("nat", "KILO-NAT"))
-	rules = append(rules, iptables.NewIPv6Chain("nat", "KILO-NAT"))
-	if cni {
-		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(t.subnet.IP)), "nat", "POSTROUTING", "-m", "comment", "--comment", "Kilo: jump to NAT chain", "-s", t.subnet.String(), "-j", "KILO-NAT"))
-	}
-	for _, s := range t.segments {
-		rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(s.wireGuardIP)), "nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: do not NAT packets destined for WireGuared IPs", "-d", s.wireGuardIP.String(), "-j", "RETURN"))
-		for _, aip := range s.allowedIPs {
-			rules = append(rules, iptables.NewRule(iptables.GetProtocol(len(aip.IP)), "nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: do not NAT packets destined for known IPs", "-d", aip.String(), "-j", "RETURN"))
-		}
-	}
-	for _, p := range t.peers {
-		for _, aip := range p.AllowedIPs {
-			rules = append(rules,
-				iptables.NewRule(iptables.GetProtocol(len(aip.IP)), "nat", "POSTROUTING", "-m", "comment", "--comment", "Kilo: jump to NAT chain", "-s", aip.String(), "-j", "KILO-NAT"),
-				iptables.NewRule(iptables.GetProtocol(len(aip.IP)), "nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: do not NAT packets destined for peers", "-d", aip.String(), "-j", "RETURN"),
-			)
-		}
-	}
-	rules = append(rules, iptables.NewIPv4Rule("nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: NAT remaining packets", "-j", "MASQUERADE"))
-	rules = append(rules, iptables.NewIPv6Rule("nat", "KILO-NAT", "-m", "comment", "--comment", "Kilo: NAT remaining packets", "-j", "MASQUERADE"))
-	return rules
-}
-
 // oneAddressCIDR takes an IP address and returns a CIDR
 // that contains only that address.
 func oneAddressCIDR(ip net.IP) *net.IPNet {
@@ -521,12 +319,3 @@ func deduplicatePeerIPs(peers []*Peer) []*Peer {
 	}
 	return ps
 }
-
-func defaultRule(rule *netlink.Rule) *netlink.Rule {
-	base := netlink.NewRule()
-	base.Src = rule.Src
-	base.Dst = rule.Dst
-	base.IifName = rule.IifName
-	base.Table = rule.Table
-	return base
-}

pkg/wireguard/wireguard.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package wireguard
 
 import (

tools.go

@@ -17,6 +17,7 @@
 package main
 
 import (
+	_ "github.com/campoy/embedmd"
 	_ "golang.org/x/lint/golint"
 	_ "k8s.io/code-generator/cmd/client-gen"
 	_ "k8s.io/code-generator/cmd/deepcopy-gen"

vendor/github.com/campoy/embedmd/.gitignore

@@ -0,0 +1,4 @@
+.vscode/
+*.test
+embed
+.DS_Store

vendor/github.com/campoy/embedmd/.travis.yml

@@ -0,0 +1,9 @@
+language: go
+
+go:
+  - 1.7.x
+  - 1.8.x
+  - 1.x
+  - master
+script:
+  - go test ./...

vendor/github.com/campoy/embedmd/LICENSE

@@ -0,0 +1,202 @@
+Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
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+   7. Disclaimer of Warranty. Unless required by applicable law or
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+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+
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+   Copyright {yyyy} {name of copyright owner}
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+

vendor/github.com/campoy/embedmd/README.md

@@ -0,0 +1,152 @@
+[![Build Status](https://travis-ci.org/campoy/embedmd.svg)](https://travis-ci.org/campoy/embedmd) [![Go Report Card](https://goreportcard.com/badge/github.com/campoy/embedmd)](https://goreportcard.com/report/github.com/campoy/embedmd)
+
+
+# embedmd
+
+Are you tired of copy pasting your code into your `README.md` file, just to
+forget about it later on and have unsynced copies? Or even worse, code
+that does not even compile?
+
+Then `embedmd` is for you!
+
+`embedmd` embeds files or fractions of files into Markdown files. It does
+so by searching `embedmd` commands, which are a subset of the Markdown
+syntax for comments. This means they are invisible when Markdown is
+rendered, so they can be kept in the file as pointers to the origin of
+the embedded text.
+
+The command receives a list of Markdown files. If no list is given, the command
+reads from the standard input.
+
+The format of an `embedmd` command is:
+
+```Markdown
+[embedmd]:# (pathOrURL language /start regexp/ /end regexp/)
+```
+
+The embedded code will be extracted from the file at `pathOrURL`,
+which can either be a relative path to a file in the local file
+system (using always forward slashes as directory separator) or
+a URL starting with `http://` or `https://`.
+If the `pathOrURL` is a URL the tool will fetch the content in that URL.
+The embedded content starts at the first line that matches `/start regexp/`
+and finishes at the first line matching `/end regexp/`.
+
+Omitting the the second regular expression will embed only the piece of text
+that matches `/regexp/`:
+
+```Markdown
+[embedmd]:# (pathOrURL language /regexp/)
+```
+
+To embed the whole line matching a regular expression you can use:
+
+```Markdown
+[embedmd]:# (pathOrURL language /.*regexp.*/)
+```
+
+To embed from a point to the end you should use:
+
+```Markdown
+[embedmd]:# (pathOrURL language /start regexp/ $)
+```
+
+To embed a whole file, omit both regular expressions:
+
+```Markdown
+[embedmd]:# (pathOrURL language)
+```
+
+You can omit the language in any of the previous commands, and the extension
+of the file will be used for the snippet syntax highlighting.
+
+This works when the file extensions matches the name of the language (like Go
+files, since `.go` matches `go`). However, this will fail with other files like
+`.md` whose language name is `markdown`.
+
+```Markdown
+[embedmd]:# (file.ext)
+```
+
+## Installation
+
+> You can install Go by following [these instructions](https://golang.org/doc/install).
+
+`embedmd` is written in Go, so if you have Go installed you can install it with
+`go get`:
+
+```
+go get github.com/campoy/embedmd
+```
+
+This will download the code, compile it, and leave an `embedmd` binary
+in `$GOPATH/bin`.
+
+Eventually, and if there's enough interest, I will provide binaries for
+every OS and architecture out there ... _eventually_.
+
+## Usage:
+
+Given the two files in [sample](sample):
+
+*hello.go:*
+
+[embedmd]:# (sample/hello.go)
+```go
+// Copyright 2016 Google Inc. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func main() {
+	fmt.Println("Hello, there, it is", time.Now())
+}
+```
+
+*docs.md:*
+
+[embedmd]:# (sample/docs.md Markdown /./ /embedmd.*time.*/)
+```Markdown
+# A hello world in Go
+
+Go is very simple, here you can see a whole "hello, world" program.
+
+[embedmd]:# (hello.go)
+
+We can try to embed a file from a directory.
+
+[embedmd]:# (test/hello.go /func main/ $)
+
+You always start with a `package` statement like:
+
+[embedmd]:# (hello.go /package.*/)
+
+Followed by an `import` statement:
+
+[embedmd]:# (hello.go /import/ /\)/)
+
+You can also see how to get the current time:
+
+[embedmd]:# (hello.go /time\.[^)]*\)/)
+```
+
+# Flags
+
+* `-w`: Executing `embedmd -w docs.md` will modify `docs.md`
+and add the corresponding code snippets, as shown in
+[sample/result.md](sample/result.md).
+
+* `-d`: Executing `embedmd -d docs.md` will display the difference
+between the contents of `docs.md` and the output of
+`embedmd docs.md`.
+
+### Disclaimer
+
+This is not an official Google product (experimental or otherwise), it is just
+code that happens to be owned by Google.

vendor/github.com/campoy/embedmd/embedmd/command.go

@@ -0,0 +1,101 @@
+// Copyright 2016 Google Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to writing, software distributed
+// under the License is distributed on a "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embedmd
+
+import (
+	"errors"
+	"path/filepath"
+	"strings"
+)
+
+type command struct {
+	path, lang string
+	start, end *string
+}
+
+func parseCommand(s string) (*command, error) {
+	s = strings.TrimSpace(s)
+	if len(s) < 2 || s[0] != '(' || s[len(s)-1] != ')' {
+		return nil, errors.New("argument list should be in parenthesis")
+	}
+
+	args, err := fields(s[1 : len(s)-1])
+	if err != nil {
+		return nil, err
+	}
+	if len(args) == 0 {
+		return nil, errors.New("missing file name")
+	}
+
+	cmd := &command{path: args[0]}
+	args = args[1:]
+	if len(args) > 0 && args[0][0] != '/' {
+		cmd.lang, args = args[0], args[1:]
+	} else {
+		ext := filepath.Ext(cmd.path[1:])
+		if len(ext) == 0 {
+			return nil, errors.New("language is required when file has no extension")
+		}
+		cmd.lang = ext[1:]
+	}
+
+	switch {
+	case len(args) == 1:
+		cmd.start = &args[0]
+	case len(args) == 2:
+		cmd.start, cmd.end = &args[0], &args[1]
+	case len(args) > 2:
+		return nil, errors.New("too many arguments")
+	}
+
+	return cmd, nil
+}
+
+// fields returns a list of the groups of text separated by blanks,
+// keeping all text surrounded by / as a group.
+func fields(s string) ([]string, error) {
+	var args []string
+
+	for s = strings.TrimSpace(s); len(s) > 0; s = strings.TrimSpace(s) {
+		if s[0] == '/' {
+			sep := nextSlash(s[1:])
+			if sep < 0 {
+				return nil, errors.New("unbalanced /")
+			}
+			args, s = append(args, s[:sep+2]), s[sep+2:]
+		} else {
+			sep := strings.IndexByte(s[1:], ' ')
+			if sep < 0 {
+				return append(args, s), nil
+			}
+			args, s = append(args, s[:sep+1]), s[sep+1:]
+		}
+	}
+
+	return args, nil
+}
+
+// nextSlash will find the index of the next unescaped slash in a string.
+func nextSlash(s string) int {
+	for sep := 0; ; sep++ {
+		i := strings.IndexByte(s[sep:], '/')
+		if i < 0 {
+			return -1
+		}
+		sep += i
+		if sep == 0 || s[sep-1] != '\\' {
+			return sep
+		}
+	}
+}

vendor/github.com/campoy/embedmd/embedmd/content.go

@@ -0,0 +1,51 @@
+// Copyright 2016 Google Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to writing, software distributed
+// under the License is distributed on a "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embedmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"path/filepath"
+	"strings"
+)
+
+// Fetcher provides an abstraction on a file system.
+// The Fetch function is called anytime some content needs to be fetched.
+// For now this includes files and URLs.
+// The first parameter is the base directory that could be used to resolve
+// relative paths. This base directory will be ignored for absolute paths,
+// such as URLs.
+type Fetcher interface {
+	Fetch(dir, path string) ([]byte, error)
+}
+
+type fetcher struct{}
+
+func (fetcher) Fetch(dir, path string) ([]byte, error) {
+	if !strings.HasPrefix(path, "http://") && !strings.HasPrefix(path, "https://") {
+		path = filepath.Join(dir, filepath.FromSlash(path))
+		return ioutil.ReadFile(path)
+	}
+
+	res, err := http.Get(path)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("status %s", res.Status)
+	}
+	return ioutil.ReadAll(res.Body)
+}

vendor/github.com/campoy/embedmd/embedmd/embedmd.go

@@ -0,0 +1,153 @@
+// Copyright 2016 Google Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to writing, software distributed
+// under the License is distributed on a "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package embedmd provides a single function, Process, that parses markdown
+// searching for markdown comments.
+//
+// The format of an embedmd command is:
+//
+//     [embedmd]:# (pathOrURL language /start regexp/ /end regexp/)
+//
+// The embedded code will be extracted from the file at pathOrURL,
+// which can either be a relative path to a file in the local file
+// system (using always forward slashes as directory separator) or
+// a url starting with http:// or https://.
+// If the pathOrURL is a url the tool will fetch the content in that url.
+// The embedded content starts at the first line that matches /start regexp/
+// and finishes at the first line matching /end regexp/.
+//
+// Omitting the the second regular expression will embed only the piece of
+// text that matches /regexp/:
+//
+//     [embedmd]:# (pathOrURL language /regexp/)
+//
+// To embed the whole line matching a regular expression you can use:
+//
+//     [embedmd]:# (pathOrURL language /.*regexp.*\n/)
+//
+// If you want to embed from a point to the end you should use:
+//
+//     [embedmd]:# (pathOrURL language /start regexp/ $)
+//
+// Finally you can embed a whole file by omitting both regular expressions:
+//
+//     [embedmd]:# (pathOrURL language)
+//
+// You can ommit the language in any of the previous commands, and the extension
+// of the file will be used for the snippet syntax highlighting. Note that while
+// this works Go files, since the file extension .go matches the name of the language
+// go, this will fail with other files like .md whose language name is markdown.
+//
+//     [embedmd]:# (file.ext)
+//
+package embedmd
+
+import (
+	"fmt"
+	"io"
+	"regexp"
+)
+
+// Process reads markdown from the given io.Reader searching for an embedmd
+// command. When a command is found, it is executed and the output is written
+// into the given io.Writer with the rest of standard markdown.
+func Process(out io.Writer, in io.Reader, opts ...Option) error {
+	e := embedder{Fetcher: fetcher{}}
+	for _, opt := range opts {
+		opt.f(&e)
+	}
+	return process(out, in, e.runCommand)
+}
+
+// An Option provides a way to adapt the Process function to your needs.
+type Option struct{ f func(*embedder) }
+
+// WithBaseDir indicates that the given path should be used to resolve relative
+// paths.
+func WithBaseDir(path string) Option {
+	return Option{func(e *embedder) { e.baseDir = path }}
+}
+
+// WithFetcher provides a custom Fetcher to be used whenever a path or url needs
+// to be fetched.
+func WithFetcher(c Fetcher) Option {
+	return Option{func(e *embedder) { e.Fetcher = c }}
+}
+
+type embedder struct {
+	Fetcher
+	baseDir string
+}
+
+func (e *embedder) runCommand(w io.Writer, cmd *command) error {
+	b, err := e.Fetch(e.baseDir, cmd.path)
+	if err != nil {
+		return fmt.Errorf("could not read %s: %v", cmd.path, err)
+	}
+
+	b, err = extract(b, cmd.start, cmd.end)
+	if err != nil {
+		return fmt.Errorf("could not extract content from %s: %v", cmd.path, err)
+	}
+
+	if len(b) > 0 && b[len(b)-1] != '\n' {
+		b = append(b, '\n')
+	}
+
+	fmt.Fprintln(w, "```"+cmd.lang)
+	w.Write(b)
+	fmt.Fprintln(w, "```")
+	return nil
+}
+
+func extract(b []byte, start, end *string) ([]byte, error) {
+	if start == nil && end == nil {
+		return b, nil
+	}
+
+	match := func(s string) ([]int, error) {
+		if len(s) <= 2 || s[0] != '/' || s[len(s)-1] != '/' {
+			return nil, fmt.Errorf("missing slashes (/) around %q", s)
+		}
+		re, err := regexp.CompilePOSIX(s[1 : len(s)-1])
+		if err != nil {
+			return nil, err
+		}
+		loc := re.FindIndex(b)
+		if loc == nil {
+			return nil, fmt.Errorf("could not match %q", s)
+		}
+		return loc, nil
+	}
+
+	if *start != "" {
+		loc, err := match(*start)
+		if err != nil {
+			return nil, err
+		}
+		if end == nil {
+			return b[loc[0]:loc[1]], nil
+		}
+		b = b[loc[0]:]
+	}
+
+	if *end != "$" {
+		loc, err := match(*end)
+		if err != nil {
+			return nil, err
+		}
+		b = b[:loc[1]]
+	}
+
+	return b, nil
+}

vendor/github.com/campoy/embedmd/embedmd/parser.go

@@ -0,0 +1,117 @@
+// Copyright 2016 Google Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to writing, software distributed
+// under the License is distributed on a "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embedmd
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type commandRunner func(io.Writer, *command) error
+
+func process(out io.Writer, in io.Reader, run commandRunner) error {
+	s := &countingScanner{bufio.NewScanner(in), 0}
+
+	state := parsingText
+	var err error
+	for state != nil {
+		state, err = state(out, s, run)
+		if err != nil {
+			return fmt.Errorf("%d: %v", s.line, err)
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return fmt.Errorf("%d: %v", s.line, err)
+	}
+	return nil
+}
+
+type countingScanner struct {
+	*bufio.Scanner
+	line int
+}
+
+func (c *countingScanner) Scan() bool {
+	b := c.Scanner.Scan()
+	if b {
+		c.line++
+	}
+	return b
+}
+
+type textScanner interface {
+	Text() string
+	Scan() bool
+}
+
+type state func(io.Writer, textScanner, commandRunner) (state, error)
+
+func parsingText(out io.Writer, s textScanner, run commandRunner) (state, error) {
+	if !s.Scan() {
+		return nil, nil // end of file, which is fine.
+	}
+	switch line := s.Text(); {
+	case strings.HasPrefix(line, "[embedmd]:#"):
+		return parsingCmd, nil
+	case strings.HasPrefix(line, "```"):
+		return codeParser{print: true}.parse, nil
+	default:
+		fmt.Fprintln(out, s.Text())
+		return parsingText, nil
+	}
+}
+
+func parsingCmd(out io.Writer, s textScanner, run commandRunner) (state, error) {
+	line := s.Text()
+	fmt.Fprintln(out, line)
+	args := line[strings.Index(line, "#")+1:]
+	cmd, err := parseCommand(args)
+	if err != nil {
+		return nil, err
+	}
+	if err := run(out, cmd); err != nil {
+		return nil, err
+	}
+	if !s.Scan() {
+		return nil, nil // end of file, which is fine.
+	}
+	if strings.HasPrefix(s.Text(), "```") {
+		return codeParser{print: false}.parse, nil
+	}
+	fmt.Fprintln(out, s.Text())
+	return parsingText, nil
+}
+
+type codeParser struct{ print bool }
+
+func (c codeParser) parse(out io.Writer, s textScanner, run commandRunner) (state, error) {
+	if c.print {
+		fmt.Fprintln(out, s.Text())
+	}
+	if !s.Scan() {
+		return nil, fmt.Errorf("unbalanced code section")
+	}
+	if !strings.HasPrefix(s.Text(), "```") {
+		return c.parse, nil
+	}
+
+	// print the end of the code section if needed and go back to parsing text.
+	if c.print {
+		fmt.Fprintln(out, s.Text())
+	}
+	return parsingText, nil
+}

vendor/github.com/campoy/embedmd/go.mod

@@ -0,0 +1,3 @@
+module github.com/campoy/embedmd
+
+require github.com/pmezard/go-difflib v1.0.0

vendor/github.com/campoy/embedmd/go.sum

@@ -0,0 +1,2 @@
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

vendor/github.com/campoy/embedmd/main.go

@@ -0,0 +1,185 @@
+// Copyright 2016 Google Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to writing, software distributed
+// under the License is distributed on a "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// embedmd
+//
+// embedmd embeds files or fractions of files into markdown files.
+// It does so by searching embedmd commands, which are a subset of the
+// markdown syntax for comments. This means they are invisible when
+// markdown is rendered, so they can be kept in the file as pointers
+// to the origin of the embedded text.
+//
+// The command receives a list of markdown files, if none is given it
+// reads from the standard input.
+//
+// embedmd supports two flags:
+// -d: will print the difference of the input file with what the output
+//     would have been if executed.
+// -w: rewrites the given files rather than writing the output to the standard
+//     output.
+//
+// For more information on the format of the commands, read the documentation
+// of the github.com/campoy/embedmd/embedmd package.
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/campoy/embedmd/embedmd"
+	"github.com/pmezard/go-difflib/difflib"
+)
+
+// modified while building by -ldflags.
+var version = "unkown"
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: embedmd [flags] [path ...]\n")
+	flag.PrintDefaults()
+}
+
+func main() {
+	rewrite := flag.Bool("w", false, "write result to (markdown) file instead of stdout")
+	doDiff := flag.Bool("d", false, "display diffs instead of rewriting files")
+	printVersion := flag.Bool("v", false, "display embedmd version")
+	flag.Usage = usage
+	flag.Parse()
+
+	if *printVersion {
+		fmt.Println("embedmd version: " + version)
+		return
+	}
+
+	diff, err := embed(flag.Args(), *rewrite, *doDiff)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+	if diff && *doDiff {
+		os.Exit(2)
+	}
+}
+
+var (
+	stdout io.Writer = os.Stdout
+	stdin  io.Reader = os.Stdin
+)
+
+func embed(paths []string, rewrite, doDiff bool) (foundDiff bool, err error) {
+	if rewrite && doDiff {
+		return false, fmt.Errorf("error: cannot use -w and -d simultaneously")
+	}
+
+	if len(paths) == 0 {
+		if rewrite {
+			return false, fmt.Errorf("error: cannot use -w with standard input")
+		}
+		if !doDiff {
+			return false, embedmd.Process(stdout, stdin)
+		}
+
+		var out, in bytes.Buffer
+		if err := embedmd.Process(&out, io.TeeReader(stdin, &in)); err != nil {
+			return false, err
+		}
+		d, err := diff(in.String(), out.String())
+		if err != nil || len(d) == 0 {
+			return false, err
+		}
+		fmt.Fprintf(stdout, "%s", d)
+		return true, nil
+	}
+
+	for _, path := range paths {
+		d, err := processFile(path, rewrite, doDiff)
+		if err != nil {
+			return false, fmt.Errorf("%s:%v", path, err)
+		}
+		foundDiff = foundDiff || d
+	}
+	return foundDiff, nil
+}
+
+type file interface {
+	io.ReadCloser
+	io.WriterAt
+	Truncate(int64) error
+}
+
+// replaced by testing functions.
+var openFile = func(name string) (file, error) {
+	return os.OpenFile(name, os.O_RDWR, 0666)
+}
+
+func readFile(path string) ([]byte, error) {
+	f, err := openFile(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return ioutil.ReadAll(f)
+}
+
+func processFile(path string, rewrite, doDiff bool) (foundDiff bool, err error) {
+	if filepath.Ext(path) != ".md" {
+		return false, fmt.Errorf("not a markdown file")
+	}
+
+	f, err := openFile(path)
+	if err != nil {
+		return false, err
+	}
+	defer f.Close()
+
+	buf := new(bytes.Buffer)
+	if err := embedmd.Process(buf, f, embedmd.WithBaseDir(filepath.Dir(path))); err != nil {
+		return false, err
+	}
+
+	if doDiff {
+		f, err := readFile(path)
+		if err != nil {
+			return false, fmt.Errorf("could not read %s for diff: %v", path, err)
+		}
+		data, err := diff(string(f), buf.String())
+		if err != nil || len(data) == 0 {
+			return false, err
+		}
+		fmt.Fprintf(stdout, "%s", data)
+		return true, nil
+	}
+
+	if rewrite {
+		n, err := f.WriteAt(buf.Bytes(), 0)
+		if err != nil {
+			return false, fmt.Errorf("could not write: %v", err)
+		}
+		return false, f.Truncate(int64(n))
+	}
+
+	io.Copy(stdout, buf)
+	return false, nil
+}
+
+func diff(a, b string) (string, error) {
+	return difflib.GetUnifiedDiffString(difflib.UnifiedDiff{
+		A:       difflib.SplitLines(a),
+		B:       difflib.SplitLines(b),
+		Context: 3,
+	})
+}

vendor/github.com/pmezard/go-difflib/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2013, Patrick Mezard
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+    The names of its contributors may not be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/pmezard/go-difflib/difflib/difflib.go

@@ -0,0 +1,772 @@
+// Package difflib is a partial port of Python difflib module.
+//
+// It provides tools to compare sequences of strings and generate textual diffs.
+//
+// The following class and functions have been ported:
+//
+// - SequenceMatcher
+//
+// - unified_diff
+//
+// - context_diff
+//
+// Getting unified diffs was the main goal of the port. Keep in mind this code
+// is mostly suitable to output text differences in a human friendly way, there
+// are no guarantees generated diffs are consumable by patch(1).
+package difflib
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func calculateRatio(matches, length int) float64 {
+	if length > 0 {
+		return 2.0 * float64(matches) / float64(length)
+	}
+	return 1.0
+}
+
+type Match struct {
+	A    int
+	B    int
+	Size int
+}
+
+type OpCode struct {
+	Tag byte
+	I1  int
+	I2  int
+	J1  int
+	J2  int
+}
+
+// SequenceMatcher compares sequence of strings. The basic
+// algorithm predates, and is a little fancier than, an algorithm
+// published in the late 1980's by Ratcliff and Obershelp under the
+// hyperbolic name "gestalt pattern matching".  The basic idea is to find
+// the longest contiguous matching subsequence that contains no "junk"
+// elements (R-O doesn't address junk).  The same idea is then applied
+// recursively to the pieces of the sequences to the left and to the right
+// of the matching subsequence.  This does not yield minimal edit
+// sequences, but does tend to yield matches that "look right" to people.
+//
+// SequenceMatcher tries to compute a "human-friendly diff" between two
+// sequences.  Unlike e.g. UNIX(tm) diff, the fundamental notion is the
+// longest *contiguous* & junk-free matching subsequence.  That's what
+// catches peoples' eyes.  The Windows(tm) windiff has another interesting
+// notion, pairing up elements that appear uniquely in each sequence.
+// That, and the method here, appear to yield more intuitive difference
+// reports than does diff.  This method appears to be the least vulnerable
+// to synching up on blocks of "junk lines", though (like blank lines in
+// ordinary text files, or maybe "<P>" lines in HTML files).  That may be
+// because this is the only method of the 3 that has a *concept* of
+// "junk" <wink>.
+//
+// Timing:  Basic R-O is cubic time worst case and quadratic time expected
+// case.  SequenceMatcher is quadratic time for the worst case and has
+// expected-case behavior dependent in a complicated way on how many
+// elements the sequences have in common; best case time is linear.
+type SequenceMatcher struct {
+	a              []string
+	b              []string
+	b2j            map[string][]int
+	IsJunk         func(string) bool
+	autoJunk       bool
+	bJunk          map[string]struct{}
+	matchingBlocks []Match
+	fullBCount     map[string]int
+	bPopular       map[string]struct{}
+	opCodes        []OpCode
+}
+
+func NewMatcher(a, b []string) *SequenceMatcher {
+	m := SequenceMatcher{autoJunk: true}
+	m.SetSeqs(a, b)
+	return &m
+}
+
+func NewMatcherWithJunk(a, b []string, autoJunk bool,
+	isJunk func(string) bool) *SequenceMatcher {
+
+	m := SequenceMatcher{IsJunk: isJunk, autoJunk: autoJunk}
+	m.SetSeqs(a, b)
+	return &m
+}
+
+// Set two sequences to be compared.
+func (m *SequenceMatcher) SetSeqs(a, b []string) {
+	m.SetSeq1(a)
+	m.SetSeq2(b)
+}
+
+// Set the first sequence to be compared. The second sequence to be compared is
+// not changed.
+//
+// SequenceMatcher computes and caches detailed information about the second
+// sequence, so if you want to compare one sequence S against many sequences,
+// use .SetSeq2(s) once and call .SetSeq1(x) repeatedly for each of the other
+// sequences.
+//
+// See also SetSeqs() and SetSeq2().
+func (m *SequenceMatcher) SetSeq1(a []string) {
+	if &a == &m.a {
+		return
+	}
+	m.a = a
+	m.matchingBlocks = nil
+	m.opCodes = nil
+}
+
+// Set the second sequence to be compared. The first sequence to be compared is
+// not changed.
+func (m *SequenceMatcher) SetSeq2(b []string) {
+	if &b == &m.b {
+		return
+	}
+	m.b = b
+	m.matchingBlocks = nil
+	m.opCodes = nil
+	m.fullBCount = nil
+	m.chainB()
+}
+
+func (m *SequenceMatcher) chainB() {
+	// Populate line -> index mapping
+	b2j := map[string][]int{}
+	for i, s := range m.b {
+		indices := b2j[s]
+		indices = append(indices, i)
+		b2j[s] = indices
+	}
+
+	// Purge junk elements
+	m.bJunk = map[string]struct{}{}
+	if m.IsJunk != nil {
+		junk := m.bJunk
+		for s, _ := range b2j {
+			if m.IsJunk(s) {
+				junk[s] = struct{}{}
+			}
+		}
+		for s, _ := range junk {
+			delete(b2j, s)
+		}
+	}
+
+	// Purge remaining popular elements
+	popular := map[string]struct{}{}
+	n := len(m.b)
+	if m.autoJunk && n >= 200 {
+		ntest := n/100 + 1
+		for s, indices := range b2j {
+			if len(indices) > ntest {
+				popular[s] = struct{}{}
+			}
+		}
+		for s, _ := range popular {
+			delete(b2j, s)
+		}
+	}
+	m.bPopular = popular
+	m.b2j = b2j
+}
+
+func (m *SequenceMatcher) isBJunk(s string) bool {
+	_, ok := m.bJunk[s]
+	return ok
+}
+
+// Find longest matching block in a[alo:ahi] and b[blo:bhi].
+//
+// If IsJunk is not defined:
+//
+// Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
+//     alo <= i <= i+k <= ahi
+//     blo <= j <= j+k <= bhi
+// and for all (i',j',k') meeting those conditions,
+//     k >= k'
+//     i <= i'
+//     and if i == i', j <= j'
+//
+// In other words, of all maximal matching blocks, return one that
+// starts earliest in a, and of all those maximal matching blocks that
+// start earliest in a, return the one that starts earliest in b.
+//
+// If IsJunk is defined, first the longest matching block is
+// determined as above, but with the additional restriction that no
+// junk element appears in the block.  Then that block is extended as
+// far as possible by matching (only) junk elements on both sides.  So
+// the resulting block never matches on junk except as identical junk
+// happens to be adjacent to an "interesting" match.
+//
+// If no blocks match, return (alo, blo, 0).
+func (m *SequenceMatcher) findLongestMatch(alo, ahi, blo, bhi int) Match {
+	// CAUTION:  stripping common prefix or suffix would be incorrect.
+	// E.g.,
+	//    ab
+	//    acab
+	// Longest matching block is "ab", but if common prefix is
+	// stripped, it's "a" (tied with "b").  UNIX(tm) diff does so
+	// strip, so ends up claiming that ab is changed to acab by
+	// inserting "ca" in the middle.  That's minimal but unintuitive:
+	// "it's obvious" that someone inserted "ac" at the front.
+	// Windiff ends up at the same place as diff, but by pairing up
+	// the unique 'b's and then matching the first two 'a's.
+	besti, bestj, bestsize := alo, blo, 0
+
+	// find longest junk-free match
+	// during an iteration of the loop, j2len[j] = length of longest
+	// junk-free match ending with a[i-1] and b[j]
+	j2len := map[int]int{}
+	for i := alo; i != ahi; i++ {
+		// look at all instances of a[i] in b; note that because
+		// b2j has no junk keys, the loop is skipped if a[i] is junk
+		newj2len := map[int]int{}
+		for _, j := range m.b2j[m.a[i]] {
+			// a[i] matches b[j]
+			if j < blo {
+				continue
+			}
+			if j >= bhi {
+				break
+			}
+			k := j2len[j-1] + 1
+			newj2len[j] = k
+			if k > bestsize {
+				besti, bestj, bestsize = i-k+1, j-k+1, k
+			}
+		}
+		j2len = newj2len
+	}
+
+	// Extend the best by non-junk elements on each end.  In particular,
+	// "popular" non-junk elements aren't in b2j, which greatly speeds
+	// the inner loop above, but also means "the best" match so far
+	// doesn't contain any junk *or* popular non-junk elements.
+	for besti > alo && bestj > blo && !m.isBJunk(m.b[bestj-1]) &&
+		m.a[besti-1] == m.b[bestj-1] {
+		besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+	}
+	for besti+bestsize < ahi && bestj+bestsize < bhi &&
+		!m.isBJunk(m.b[bestj+bestsize]) &&
+		m.a[besti+bestsize] == m.b[bestj+bestsize] {
+		bestsize += 1
+	}
+
+	// Now that we have a wholly interesting match (albeit possibly
+	// empty!), we may as well suck up the matching junk on each
+	// side of it too.  Can't think of a good reason not to, and it
+	// saves post-processing the (possibly considerable) expense of
+	// figuring out what to do with it.  In the case of an empty
+	// interesting match, this is clearly the right thing to do,
+	// because no other kind of match is possible in the regions.
+	for besti > alo && bestj > blo && m.isBJunk(m.b[bestj-1]) &&
+		m.a[besti-1] == m.b[bestj-1] {
+		besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+	}
+	for besti+bestsize < ahi && bestj+bestsize < bhi &&
+		m.isBJunk(m.b[bestj+bestsize]) &&
+		m.a[besti+bestsize] == m.b[bestj+bestsize] {
+		bestsize += 1
+	}
+
+	return Match{A: besti, B: bestj, Size: bestsize}
+}
+
+// Return list of triples describing matching subsequences.
+//
+// Each triple is of the form (i, j, n), and means that
+// a[i:i+n] == b[j:j+n].  The triples are monotonically increasing in
+// i and in j. It's also guaranteed that if (i, j, n) and (i', j', n') are
+// adjacent triples in the list, and the second is not the last triple in the
+// list, then i+n != i' or j+n != j'. IOW, adjacent triples never describe
+// adjacent equal blocks.
+//
+// The last triple is a dummy, (len(a), len(b), 0), and is the only
+// triple with n==0.
+func (m *SequenceMatcher) GetMatchingBlocks() []Match {
+	if m.matchingBlocks != nil {
+		return m.matchingBlocks
+	}
+
+	var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match
+	matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match {
+		match := m.findLongestMatch(alo, ahi, blo, bhi)
+		i, j, k := match.A, match.B, match.Size
+		if match.Size > 0 {
+			if alo < i && blo < j {
+				matched = matchBlocks(alo, i, blo, j, matched)
+			}
+			matched = append(matched, match)
+			if i+k < ahi && j+k < bhi {
+				matched = matchBlocks(i+k, ahi, j+k, bhi, matched)
+			}
+		}
+		return matched
+	}
+	matched := matchBlocks(0, len(m.a), 0, len(m.b), nil)
+
+	// It's possible that we have adjacent equal blocks in the
+	// matching_blocks list now.
+	nonAdjacent := []Match{}
+	i1, j1, k1 := 0, 0, 0
+	for _, b := range matched {
+		// Is this block adjacent to i1, j1, k1?
+		i2, j2, k2 := b.A, b.B, b.Size
+		if i1+k1 == i2 && j1+k1 == j2 {
+			// Yes, so collapse them -- this just increases the length of
+			// the first block by the length of the second, and the first
+			// block so lengthened remains the block to compare against.
+			k1 += k2
+		} else {
+			// Not adjacent.  Remember the first block (k1==0 means it's
+			// the dummy we started with), and make the second block the
+			// new block to compare against.
+			if k1 > 0 {
+				nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
+			}
+			i1, j1, k1 = i2, j2, k2
+		}
+	}
+	if k1 > 0 {
+		nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
+	}
+
+	nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0})
+	m.matchingBlocks = nonAdjacent
+	return m.matchingBlocks
+}
+
+// Return list of 5-tuples describing how to turn a into b.
+//
+// Each tuple is of the form (tag, i1, i2, j1, j2).  The first tuple
+// has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
+// tuple preceding it, and likewise for j1 == the previous j2.
+//
+// The tags are characters, with these meanings:
+//
+// 'r' (replace):  a[i1:i2] should be replaced by b[j1:j2]
+//
+// 'd' (delete):   a[i1:i2] should be deleted, j1==j2 in this case.
+//
+// 'i' (insert):   b[j1:j2] should be inserted at a[i1:i1], i1==i2 in this case.
+//
+// 'e' (equal):    a[i1:i2] == b[j1:j2]
+func (m *SequenceMatcher) GetOpCodes() []OpCode {
+	if m.opCodes != nil {
+		return m.opCodes
+	}
+	i, j := 0, 0
+	matching := m.GetMatchingBlocks()
+	opCodes := make([]OpCode, 0, len(matching))
+	for _, m := range matching {
+		//  invariant:  we've pumped out correct diffs to change
+		//  a[:i] into b[:j], and the next matching block is
+		//  a[ai:ai+size] == b[bj:bj+size]. So we need to pump
+		//  out a diff to change a[i:ai] into b[j:bj], pump out
+		//  the matching block, and move (i,j) beyond the match
+		ai, bj, size := m.A, m.B, m.Size
+		tag := byte(0)
+		if i < ai && j < bj {
+			tag = 'r'
+		} else if i < ai {
+			tag = 'd'
+		} else if j < bj {
+			tag = 'i'
+		}
+		if tag > 0 {
+			opCodes = append(opCodes, OpCode{tag, i, ai, j, bj})
+		}
+		i, j = ai+size, bj+size
+		// the list of matching blocks is terminated by a
+		// sentinel with size 0
+		if size > 0 {
+			opCodes = append(opCodes, OpCode{'e', ai, i, bj, j})
+		}
+	}
+	m.opCodes = opCodes
+	return m.opCodes
+}
+
+// Isolate change clusters by eliminating ranges with no changes.
+//
+// Return a generator of groups with up to n lines of context.
+// Each group is in the same format as returned by GetOpCodes().
+func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode {
+	if n < 0 {
+		n = 3
+	}
+	codes := m.GetOpCodes()
+	if len(codes) == 0 {
+		codes = []OpCode{OpCode{'e', 0, 1, 0, 1}}
+	}
+	// Fixup leading and trailing groups if they show no changes.
+	if codes[0].Tag == 'e' {
+		c := codes[0]
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		codes[0] = OpCode{c.Tag, max(i1, i2-n), i2, max(j1, j2-n), j2}
+	}
+	if codes[len(codes)-1].Tag == 'e' {
+		c := codes[len(codes)-1]
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		codes[len(codes)-1] = OpCode{c.Tag, i1, min(i2, i1+n), j1, min(j2, j1+n)}
+	}
+	nn := n + n
+	groups := [][]OpCode{}
+	group := []OpCode{}
+	for _, c := range codes {
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		// End the current group and start a new one whenever
+		// there is a large range with no changes.
+		if c.Tag == 'e' && i2-i1 > nn {
+			group = append(group, OpCode{c.Tag, i1, min(i2, i1+n),
+				j1, min(j2, j1+n)})
+			groups = append(groups, group)
+			group = []OpCode{}
+			i1, j1 = max(i1, i2-n), max(j1, j2-n)
+		}
+		group = append(group, OpCode{c.Tag, i1, i2, j1, j2})
+	}
+	if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') {
+		groups = append(groups, group)
+	}
+	return groups
+}
+
+// Return a measure of the sequences' similarity (float in [0,1]).
+//
+// Where T is the total number of elements in both sequences, and
+// M is the number of matches, this is 2.0*M / T.
+// Note that this is 1 if the sequences are identical, and 0 if
+// they have nothing in common.
+//
+// .Ratio() is expensive to compute if you haven't already computed
+// .GetMatchingBlocks() or .GetOpCodes(), in which case you may
+// want to try .QuickRatio() or .RealQuickRation() first to get an
+// upper bound.
+func (m *SequenceMatcher) Ratio() float64 {
+	matches := 0
+	for _, m := range m.GetMatchingBlocks() {
+		matches += m.Size
+	}
+	return calculateRatio(matches, len(m.a)+len(m.b))
+}
+
+// Return an upper bound on ratio() relatively quickly.
+//
+// This isn't defined beyond that it is an upper bound on .Ratio(), and
+// is faster to compute.
+func (m *SequenceMatcher) QuickRatio() float64 {
+	// viewing a and b as multisets, set matches to the cardinality
+	// of their intersection; this counts the number of matches
+	// without regard to order, so is clearly an upper bound
+	if m.fullBCount == nil {
+		m.fullBCount = map[string]int{}
+		for _, s := range m.b {
+			m.fullBCount[s] = m.fullBCount[s] + 1
+		}
+	}
+
+	// avail[x] is the number of times x appears in 'b' less the
+	// number of times we've seen it in 'a' so far ... kinda
+	avail := map[string]int{}
+	matches := 0
+	for _, s := range m.a {
+		n, ok := avail[s]
+		if !ok {
+			n = m.fullBCount[s]
+		}
+		avail[s] = n - 1
+		if n > 0 {
+			matches += 1
+		}
+	}
+	return calculateRatio(matches, len(m.a)+len(m.b))
+}
+
+// Return an upper bound on ratio() very quickly.
+//
+// This isn't defined beyond that it is an upper bound on .Ratio(), and
+// is faster to compute than either .Ratio() or .QuickRatio().
+func (m *SequenceMatcher) RealQuickRatio() float64 {
+	la, lb := len(m.a), len(m.b)
+	return calculateRatio(min(la, lb), la+lb)
+}
+
+// Convert range to the "ed" format
+func formatRangeUnified(start, stop int) string {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	beginning := start + 1 // lines start numbering with one
+	length := stop - start
+	if length == 1 {
+		return fmt.Sprintf("%d", beginning)
+	}
+	if length == 0 {
+		beginning -= 1 // empty ranges begin at line just before the range
+	}
+	return fmt.Sprintf("%d,%d", beginning, length)
+}
+
+// Unified diff parameters
+type UnifiedDiff struct {
+	A        []string // First sequence lines
+	FromFile string   // First file name
+	FromDate string   // First file time
+	B        []string // Second sequence lines
+	ToFile   string   // Second file name
+	ToDate   string   // Second file time
+	Eol      string   // Headers end of line, defaults to LF
+	Context  int      // Number of context lines
+}
+
+// Compare two sequences of lines; generate the delta as a unified diff.
+//
+// Unified diffs are a compact way of showing line changes and a few
+// lines of context.  The number of context lines is set by 'n' which
+// defaults to three.
+//
+// By default, the diff control lines (those with ---, +++, or @@) are
+// created with a trailing newline.  This is helpful so that inputs
+// created from file.readlines() result in diffs that are suitable for
+// file.writelines() since both the inputs and outputs have trailing
+// newlines.
+//
+// For inputs that do not have trailing newlines, set the lineterm
+// argument to "" so that the output will be uniformly newline free.
+//
+// The unidiff format normally has a header for filenames and modification
+// times.  Any or all of these may be specified using strings for
+// 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
+// The modification times are normally expressed in the ISO 8601 format.
+func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error {
+	buf := bufio.NewWriter(writer)
+	defer buf.Flush()
+	wf := func(format string, args ...interface{}) error {
+		_, err := buf.WriteString(fmt.Sprintf(format, args...))
+		return err
+	}
+	ws := func(s string) error {
+		_, err := buf.WriteString(s)
+		return err
+	}
+
+	if len(diff.Eol) == 0 {
+		diff.Eol = "\n"
+	}
+
+	started := false
+	m := NewMatcher(diff.A, diff.B)
+	for _, g := range m.GetGroupedOpCodes(diff.Context) {
+		if !started {
+			started = true
+			fromDate := ""
+			if len(diff.FromDate) > 0 {
+				fromDate = "\t" + diff.FromDate
+			}
+			toDate := ""
+			if len(diff.ToDate) > 0 {
+				toDate = "\t" + diff.ToDate
+			}
+			if diff.FromFile != "" || diff.ToFile != "" {
+				err := wf("--- %s%s%s", diff.FromFile, fromDate, diff.Eol)
+				if err != nil {
+					return err
+				}
+				err = wf("+++ %s%s%s", diff.ToFile, toDate, diff.Eol)
+				if err != nil {
+					return err
+				}
+			}
+		}
+		first, last := g[0], g[len(g)-1]
+		range1 := formatRangeUnified(first.I1, last.I2)
+		range2 := formatRangeUnified(first.J1, last.J2)
+		if err := wf("@@ -%s +%s @@%s", range1, range2, diff.Eol); err != nil {
+			return err
+		}
+		for _, c := range g {
+			i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+			if c.Tag == 'e' {
+				for _, line := range diff.A[i1:i2] {
+					if err := ws(" " + line); err != nil {
+						return err
+					}
+				}
+				continue
+			}
+			if c.Tag == 'r' || c.Tag == 'd' {
+				for _, line := range diff.A[i1:i2] {
+					if err := ws("-" + line); err != nil {
+						return err
+					}
+				}
+			}
+			if c.Tag == 'r' || c.Tag == 'i' {
+				for _, line := range diff.B[j1:j2] {
+					if err := ws("+" + line); err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// Like WriteUnifiedDiff but returns the diff a string.
+func GetUnifiedDiffString(diff UnifiedDiff) (string, error) {
+	w := &bytes.Buffer{}
+	err := WriteUnifiedDiff(w, diff)
+	return string(w.Bytes()), err
+}
+
+// Convert range to the "ed" format.
+func formatRangeContext(start, stop int) string {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	beginning := start + 1 // lines start numbering with one
+	length := stop - start
+	if length == 0 {
+		beginning -= 1 // empty ranges begin at line just before the range
+	}
+	if length <= 1 {
+		return fmt.Sprintf("%d", beginning)
+	}
+	return fmt.Sprintf("%d,%d", beginning, beginning+length-1)
+}
+
+type ContextDiff UnifiedDiff
+
+// Compare two sequences of lines; generate the delta as a context diff.
+//
+// Context diffs are a compact way of showing line changes and a few
+// lines of context. The number of context lines is set by diff.Context
+// which defaults to three.
+//
+// By default, the diff control lines (those with *** or ---) are
+// created with a trailing newline.
+//
+// For inputs that do not have trailing newlines, set the diff.Eol
+// argument to "" so that the output will be uniformly newline free.
+//
+// The context diff format normally has a header for filenames and
+// modification times.  Any or all of these may be specified using
+// strings for diff.FromFile, diff.ToFile, diff.FromDate, diff.ToDate.
+// The modification times are normally expressed in the ISO 8601 format.
+// If not specified, the strings default to blanks.
+func WriteContextDiff(writer io.Writer, diff ContextDiff) error {
+	buf := bufio.NewWriter(writer)
+	defer buf.Flush()
+	var diffErr error
+	wf := func(format string, args ...interface{}) {
+		_, err := buf.WriteString(fmt.Sprintf(format, args...))
+		if diffErr == nil && err != nil {
+			diffErr = err
+		}
+	}
+	ws := func(s string) {
+		_, err := buf.WriteString(s)
+		if diffErr == nil && err != nil {
+			diffErr = err
+		}
+	}
+
+	if len(diff.Eol) == 0 {
+		diff.Eol = "\n"
+	}
+
+	prefix := map[byte]string{
+		'i': "+ ",
+		'd': "- ",
+		'r': "! ",
+		'e': "  ",
+	}
+
+	started := false
+	m := NewMatcher(diff.A, diff.B)
+	for _, g := range m.GetGroupedOpCodes(diff.Context) {
+		if !started {
+			started = true
+			fromDate := ""
+			if len(diff.FromDate) > 0 {
+				fromDate = "\t" + diff.FromDate
+			}
+			toDate := ""
+			if len(diff.ToDate) > 0 {
+				toDate = "\t" + diff.ToDate
+			}
+			if diff.FromFile != "" || diff.ToFile != "" {
+				wf("*** %s%s%s", diff.FromFile, fromDate, diff.Eol)
+				wf("--- %s%s%s", diff.ToFile, toDate, diff.Eol)
+			}
+		}
+
+		first, last := g[0], g[len(g)-1]
+		ws("***************" + diff.Eol)
+
+		range1 := formatRangeContext(first.I1, last.I2)
+		wf("*** %s ****%s", range1, diff.Eol)
+		for _, c := range g {
+			if c.Tag == 'r' || c.Tag == 'd' {
+				for _, cc := range g {
+					if cc.Tag == 'i' {
+						continue
+					}
+					for _, line := range diff.A[cc.I1:cc.I2] {
+						ws(prefix[cc.Tag] + line)
+					}
+				}
+				break
+			}
+		}
+
+		range2 := formatRangeContext(first.J1, last.J2)
+		wf("--- %s ----%s", range2, diff.Eol)
+		for _, c := range g {
+			if c.Tag == 'r' || c.Tag == 'i' {
+				for _, cc := range g {
+					if cc.Tag == 'd' {
+						continue
+					}
+					for _, line := range diff.B[cc.J1:cc.J2] {
+						ws(prefix[cc.Tag] + line)
+					}
+				}
+				break
+			}
+		}
+	}
+	return diffErr
+}
+
+// Like WriteContextDiff but returns the diff a string.
+func GetContextDiffString(diff ContextDiff) (string, error) {
+	w := &bytes.Buffer{}
+	err := WriteContextDiff(w, diff)
+	return string(w.Bytes()), err
+}
+
+// Split a string on "\n" while preserving them. The output can be used
+// as input for UnifiedDiff and ContextDiff structures.
+func SplitLines(s string) []string {
+	lines := strings.SplitAfter(s, "\n")
+	lines[len(lines)-1] += "\n"
+	return lines
+}

vendor/modules.txt

@@ -16,6 +16,10 @@ github.com/awalterschulze/gographviz/internal/parser
 github.com/awalterschulze/gographviz/internal/token
 # github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973
 github.com/beorn7/perks/quantile
+# github.com/campoy/embedmd v1.0.0
+## explicit
+github.com/campoy/embedmd
+github.com/campoy/embedmd/embedmd
 # github.com/containernetworking/cni v0.6.0
 ## explicit
 github.com/containernetworking/cni/libcni
@@ -128,6 +132,8 @@ github.com/oklog/run
 ## explicit
 # github.com/onsi/gomega v1.5.0
 ## explicit
+# github.com/pmezard/go-difflib v1.0.0
+github.com/pmezard/go-difflib/difflib
 # github.com/prometheus/client_golang v0.9.2
 ## explicit
 github.com/prometheus/client_golang/prometheus
@@ -148,6 +154,7 @@ github.com/prometheus/procfs/xfs
 ## explicit
 github.com/spf13/cobra
 # github.com/spf13/pflag v1.0.3
+## explicit
 github.com/spf13/pflag
 # github.com/stretchr/testify v1.3.0
 ## explicit

website/docs/kg

@@ -0,0 +1,4 @@
+---
+id: kg
+hide_title: true
+---

website/docs/userspace-wireguard

@@ -0,0 +1,5 @@
+---
+id: userspace-wireguard
+title: Userspace WireGuard
+hide_title: true
+---

website/docusaurus.config.js

@@ -13,7 +13,7 @@ module.exports = {
         alt: 'Kilo',
         src: 'img/kilo.svg',
       },
-      links: [
+      items: [
         {
           to: 'docs/introduction',
           activeBasePath: 'docs',

website/package.json

@@ -9,10 +9,9 @@
     "deploy": "docusaurus deploy"
   },
   "dependencies": {
-    "@docusaurus/core": "^2.0.0-alpha.56",
-    "@docusaurus/preset-classic": "^2.0.0-alpha.56",
+    "@docusaurus/core": "2.0.0-alpha.71",
+    "@docusaurus/preset-classic": "2.0.0-alpha.71",
     "classnames": "^2.2.6",
-    "minimist": "^1.2.3",
     "react": "^16.8.4",
     "react-dom": "^16.8.4"
   },
@@ -27,5 +26,9 @@
       "last 1 firefox version",
       "last 1 safari version"
     ]
+  },
+  "resolutions": {
+    "minimist": "^1.2.3",
+    "node-fetch": "^2.6.1"
   }
 }

website/sidebars.js

@@ -7,12 +7,12 @@ module.exports = {
     {
       type: 'category',
       label: 'Guides',
-      items: ['topology', 'vpn', 'vpn-server', 'multi-cluster-services', 'network-policies'],
+      items: ['topology', 'vpn', 'vpn-server', 'multi-cluster-services', 'network-policies', 'userspace-wireguard'],
     },
     {
       type: 'category',
       label: 'Reference',
-      items: ['annotations', 'kgctl'],
+      items: ['annotations', 'kg', 'kgctl'],
     },
     //Features: ['mdx'],
   ],