kilo/pkg/k8s/backend.go
Lucas Servén Marín aa376ff0d1
pkg/mesh,pkg/wireguard: allow DNS name endpoints
This commit allows DNS names to be used when specifying the endpoint
for a node in the WireGuard mesh. This is useful in many scenarios, in
particular when operating an IoT device whose public IP is dynamic. This
change allows the administrator to use a dynamic DNS name in the node's
endpoint.

One of the side-effects of this change is that the WireGuard port can
now be specified individually for each node in the mesh, if the
administrator wishes to do so.

*Note*: this commit introduces a breaking change; the
`force-external-ip` node annotation has been removed; its functionality
has been ported over to the `force-endpoint` annotation. This annotation
is documented in the annotations.md file. The expected content of this
annotation is no longer a CIDR but rather a host:port. The host can be
either a DNS name or an IP.

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>
2020-02-22 17:17:13 +01:00

524 lines
16 KiB
Go

// 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 k8s
import (
"encoding/json"
"errors"
"fmt"
"net"
"path"
"strconv"
"strings"
"time"
crdutils "github.com/ant31/crd-validation/pkg"
v1 "k8s.io/api/core/v1"
"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
apiextensions "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/types"
"k8s.io/apimachinery/pkg/util/strategicpatch"
"k8s.io/apimachinery/pkg/util/validation"
v1informers "k8s.io/client-go/informers/core/v1"
"k8s.io/client-go/kubernetes"
v1listers "k8s.io/client-go/listers/core/v1"
"k8s.io/client-go/tools/cache"
"github.com/squat/kilo/pkg/k8s/apis/kilo/v1alpha1"
kiloclient "github.com/squat/kilo/pkg/k8s/clientset/versioned"
v1alpha1informers "github.com/squat/kilo/pkg/k8s/informers/kilo/v1alpha1"
v1alpha1listers "github.com/squat/kilo/pkg/k8s/listers/kilo/v1alpha1"
"github.com/squat/kilo/pkg/mesh"
"github.com/squat/kilo/pkg/wireguard"
)
const (
// Backend is the name of this mesh backend.
Backend = "kubernetes"
endpointAnnotationKey = "kilo.squat.ai/endpoint"
forceEndpointAnnotationKey = "kilo.squat.ai/force-endpoint"
forceInternalIPAnnotationKey = "kilo.squat.ai/force-internal-ip"
internalIPAnnotationKey = "kilo.squat.ai/internal-ip"
keyAnnotationKey = "kilo.squat.ai/key"
lastSeenAnnotationKey = "kilo.squat.ai/last-seen"
leaderAnnotationKey = "kilo.squat.ai/leader"
locationAnnotationKey = "kilo.squat.ai/location"
persistentKeepaliveKey = "kilo.squat.ai/persistent-keepalive"
wireGuardIPAnnotationKey = "kilo.squat.ai/wireguard-ip"
regionLabelKey = "topology.kubernetes.io/region"
jsonPatchSlash = "~1"
jsonRemovePatch = `{"op": "remove", "path": "%s"}`
)
type backend struct {
nodes *nodeBackend
peers *peerBackend
}
// Nodes implements the mesh.Backend interface.
func (b *backend) Nodes() mesh.NodeBackend {
return b.nodes
}
// Peers implements the mesh.Backend interface.
func (b *backend) Peers() mesh.PeerBackend {
return b.peers
}
type nodeBackend struct {
client kubernetes.Interface
events chan *mesh.NodeEvent
informer cache.SharedIndexInformer
lister v1listers.NodeLister
}
type peerBackend struct {
client kiloclient.Interface
extensionsClient apiextensions.Interface
events chan *mesh.PeerEvent
informer cache.SharedIndexInformer
lister v1alpha1listers.PeerLister
}
// New creates a new instance of a mesh.Backend.
func New(c kubernetes.Interface, kc kiloclient.Interface, ec apiextensions.Interface) 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()),
},
&peerBackend{
client: kc,
extensionsClient: ec,
events: make(chan *mesh.PeerEvent),
informer: pi,
lister: v1alpha1listers.NewPeerLister(pi.GetIndexer()),
},
}
}
// CleanUp removes configuration applied to the backend.
func (nb *nodeBackend) CleanUp(name string) error {
patch := []byte("[" + strings.Join([]string{
fmt.Sprintf(jsonRemovePatch, path.Join("/metadata", "annotations", strings.Replace(endpointAnnotationKey, "/", jsonPatchSlash, 1))),
fmt.Sprintf(jsonRemovePatch, path.Join("/metadata", "annotations", strings.Replace(internalIPAnnotationKey, "/", jsonPatchSlash, 1))),
fmt.Sprintf(jsonRemovePatch, path.Join("/metadata", "annotations", strings.Replace(keyAnnotationKey, "/", jsonPatchSlash, 1))),
fmt.Sprintf(jsonRemovePatch, path.Join("/metadata", "annotations", strings.Replace(lastSeenAnnotationKey, "/", jsonPatchSlash, 1))),
fmt.Sprintf(jsonRemovePatch, path.Join("/metadata", "annotations", strings.Replace(wireGuardIPAnnotationKey, "/", jsonPatchSlash, 1))),
}, ",") + "]")
if _, err := nb.client.CoreV1().Nodes().Patch(name, types.JSONPatchType, patch); err != nil {
return fmt.Errorf("failed to patch node: %v", err)
}
return nil
}
// Get gets a single Node by name.
func (nb *nodeBackend) Get(name string) (*mesh.Node, error) {
n, err := nb.lister.Get(name)
if err != nil {
return nil, err
}
return translateNode(n), nil
}
// Init initializes the backend; for this backend that means
// syncing the informer cache.
func (nb *nodeBackend) Init(stop <-chan struct{}) error {
go nb.informer.Run(stop)
if ok := cache.WaitForCacheSync(stop, func() bool {
return nb.informer.HasSynced()
}); !ok {
return errors.New("failed to sync node cache")
}
nb.informer.AddEventHandler(
cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
n, ok := obj.(*v1.Node)
if !ok {
// Failed to decode Node; ignoring...
return
}
nb.events <- &mesh.NodeEvent{Type: mesh.AddEvent, Node: translateNode(n)}
},
UpdateFunc: func(old, obj interface{}) {
n, ok := obj.(*v1.Node)
if !ok {
// Failed to decode Node; ignoring...
return
}
o, ok := old.(*v1.Node)
if !ok {
// Failed to decode Node; ignoring...
return
}
nb.events <- &mesh.NodeEvent{Type: mesh.UpdateEvent, Node: translateNode(n), Old: translateNode(o)}
},
DeleteFunc: func(obj interface{}) {
n, ok := obj.(*v1.Node)
if !ok {
// Failed to decode Node; ignoring...
return
}
nb.events <- &mesh.NodeEvent{Type: mesh.DeleteEvent, Node: translateNode(n)}
},
},
)
return nil
}
// List gets all the Nodes in the cluster.
func (nb *nodeBackend) List() ([]*mesh.Node, error) {
ns, err := nb.lister.List(labels.Everything())
if err != nil {
return nil, err
}
nodes := make([]*mesh.Node, len(ns))
for i := range ns {
nodes[i] = translateNode(ns[i])
}
return nodes, nil
}
// Set sets the fields of a node.
func (nb *nodeBackend) Set(name string, node *mesh.Node) error {
old, err := nb.lister.Get(name)
if err != nil {
return fmt.Errorf("failed to find node: %v", err)
}
n := old.DeepCopy()
n.ObjectMeta.Annotations[endpointAnnotationKey] = node.Endpoint.String()
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 {
n.ObjectMeta.Annotations[wireGuardIPAnnotationKey] = ""
} else {
n.ObjectMeta.Annotations[wireGuardIPAnnotationKey] = node.WireGuardIP.String()
}
oldData, err := json.Marshal(old)
if err != nil {
return err
}
newData, err := json.Marshal(n)
if err != nil {
return err
}
patch, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, v1.Node{})
if err != nil {
return fmt.Errorf("failed to create patch for node %q: %v", n.Name, err)
}
if _, err = nb.client.CoreV1().Nodes().Patch(name, types.StrategicMergePatchType, patch); err != nil {
return fmt.Errorf("failed to patch node: %v", err)
}
return nil
}
// Watch returns a chan of node events.
func (nb *nodeBackend) Watch() <-chan *mesh.NodeEvent {
return nb.events
}
// translateNode translates a Kubernetes Node to a mesh.Node.
func translateNode(node *v1.Node) *mesh.Node {
if node == nil {
return nil
}
_, subnet, err := net.ParseCIDR(node.Spec.PodCIDR)
// The subnet should only ever fail to parse if the pod CIDR has not been set,
// so in this case set the subnet to nil and let the node be updated.
if err != nil {
subnet = nil
}
_, leader := node.ObjectMeta.Annotations[leaderAnnotationKey]
// Allow the region to be overridden by an explicit location.
location, ok := node.ObjectMeta.Annotations[locationAnnotationKey]
if !ok {
location = node.ObjectMeta.Labels[regionLabelKey]
}
// Allow the endpoint to be overridden.
endpoint := parseEndpoint(node.ObjectMeta.Annotations[forceEndpointAnnotationKey])
if endpoint == nil {
endpoint = parseEndpoint(node.ObjectMeta.Annotations[endpointAnnotationKey])
}
// Allow the internal IP to be overridden.
internalIP := normalizeIP(node.ObjectMeta.Annotations[forceInternalIPAnnotationKey])
if internalIP == nil {
internalIP = normalizeIP(node.ObjectMeta.Annotations[internalIPAnnotationKey])
}
// Set Wireguard PersistentKeepalive setting for the node.
var persistentKeepalive int64
if keepAlive, ok := node.ObjectMeta.Annotations[persistentKeepaliveKey]; !ok {
persistentKeepalive = 0
} else {
if persistentKeepalive, err = strconv.ParseInt(keepAlive, 10, 64); err != nil {
persistentKeepalive = 0
}
}
var lastSeen int64
if ls, ok := node.ObjectMeta.Annotations[lastSeenAnnotationKey]; !ok {
lastSeen = 0
} else {
if lastSeen, err = strconv.ParseInt(ls, 10, 64); err != nil {
lastSeen = 0
}
}
return &mesh.Node{
// Endpoint and InternalIP should only ever fail to parse if the
// 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.
Endpoint: endpoint,
InternalIP: internalIP,
Key: []byte(node.ObjectMeta.Annotations[keyAnnotationKey]),
LastSeen: lastSeen,
Leader: leader,
Location: location,
Name: node.Name,
PersistentKeepalive: int(persistentKeepalive),
Subnet: subnet,
// WireGuardIP can fail to parse if the node is not a leader or if
// the node's agent has not yet reconciled. In either case, the IP
// will parse as nil.
WireGuardIP: normalizeIP(node.ObjectMeta.Annotations[wireGuardIPAnnotationKey]),
}
}
// translatePeer translates a Peer CRD to a mesh.Peer.
func translatePeer(peer *v1alpha1.Peer) *mesh.Peer {
if peer == nil {
return nil
}
var aips []*net.IPNet
for _, aip := range peer.Spec.AllowedIPs {
aip := normalizeIP(aip)
// Skip any invalid IPs.
if aip == nil {
continue
}
aips = append(aips, aip)
}
var endpoint *wireguard.Endpoint
if peer.Spec.Endpoint != nil {
ip := net.ParseIP(peer.Spec.Endpoint.IP)
if ip4 := ip.To4(); ip4 != nil {
ip = ip4
} else {
ip = ip.To16()
}
if peer.Spec.Endpoint.Port > 0 && ip != nil {
endpoint = &wireguard.Endpoint{
DNSOrIP: wireguard.DNSOrIP{IP: ip},
Port: peer.Spec.Endpoint.Port,
}
}
}
var key []byte
if len(peer.Spec.PublicKey) > 0 {
key = []byte(peer.Spec.PublicKey)
}
var pka int
if peer.Spec.PersistentKeepalive > 0 {
pka = peer.Spec.PersistentKeepalive
}
return &mesh.Peer{
Name: peer.Name,
Peer: wireguard.Peer{
AllowedIPs: aips,
Endpoint: endpoint,
PublicKey: key,
PersistentKeepalive: pka,
},
}
}
// CleanUp removes configuration applied to the backend.
func (pb *peerBackend) CleanUp(name string) error {
return nil
}
// Get gets a single Peer by name.
func (pb *peerBackend) Get(name string) (*mesh.Peer, error) {
p, err := pb.lister.Get(name)
if err != nil {
return nil, err
}
return translatePeer(p), nil
}
// Init initializes the backend; for this backend that means
// syncing the informer cache.
func (pb *peerBackend) Init(stop <-chan struct{}) error {
// Register CRD.
crd := crdutils.NewCustomResourceDefinition(crdutils.Config{
SpecDefinitionName: "github.com/squat/kilo/pkg/k8s/apis/kilo/v1alpha1.Peer",
EnableValidation: true,
ResourceScope: string(v1beta1.ClusterScoped),
Group: v1alpha1.GroupName,
Kind: v1alpha1.PeerKind,
Version: v1alpha1.SchemeGroupVersion.Version,
Plural: v1alpha1.PeerPlural,
ShortNames: v1alpha1.PeerShortNames,
GetOpenAPIDefinitions: v1alpha1.GetOpenAPIDefinitions,
})
crd.Spec.Subresources.Scale = nil
crd.Spec.Subresources.Status = nil
_, err := pb.extensionsClient.ApiextensionsV1beta1().CustomResourceDefinitions().Create(crd)
if err != nil && !apierrors.IsAlreadyExists(err) {
return fmt.Errorf("failed to create CRD: %v", err)
}
go pb.informer.Run(stop)
if ok := cache.WaitForCacheSync(stop, func() bool {
return pb.informer.HasSynced()
}); !ok {
return errors.New("failed to sync peer cache")
}
pb.informer.AddEventHandler(
cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
p, ok := obj.(*v1alpha1.Peer)
if !ok || p.Validate() != nil {
// Failed to decode Peer; ignoring...
return
}
pb.events <- &mesh.PeerEvent{Type: mesh.AddEvent, Peer: translatePeer(p)}
},
UpdateFunc: func(old, obj interface{}) {
p, ok := obj.(*v1alpha1.Peer)
if !ok || p.Validate() != nil {
// Failed to decode Peer; ignoring...
return
}
o, ok := old.(*v1alpha1.Peer)
if !ok || o.Validate() != nil {
// Failed to decode Peer; ignoring...
return
}
pb.events <- &mesh.PeerEvent{Type: mesh.UpdateEvent, Peer: translatePeer(p), Old: translatePeer(o)}
},
DeleteFunc: func(obj interface{}) {
p, ok := obj.(*v1alpha1.Peer)
if !ok || p.Validate() != nil {
// Failed to decode Peer; ignoring...
return
}
pb.events <- &mesh.PeerEvent{Type: mesh.DeleteEvent, Peer: translatePeer(p)}
},
},
)
return nil
}
// List gets all the Peers in the cluster.
func (pb *peerBackend) List() ([]*mesh.Peer, error) {
ps, err := pb.lister.List(labels.Everything())
if err != nil {
return nil, err
}
peers := make([]*mesh.Peer, len(ps))
for i := range ps {
// Skip invalid peers.
if ps[i].Validate() != nil {
continue
}
peers[i] = translatePeer(ps[i])
}
return peers, nil
}
// Set sets the fields of a peer.
func (pb *peerBackend) Set(name string, peer *mesh.Peer) error {
old, err := pb.lister.Get(name)
if err != nil {
return fmt.Errorf("failed to find peer: %v", err)
}
p := old.DeepCopy()
p.Spec.AllowedIPs = make([]string, len(peer.AllowedIPs))
for i := range peer.AllowedIPs {
p.Spec.AllowedIPs[i] = peer.AllowedIPs[i].String()
}
if peer.Endpoint != nil {
p.Spec.Endpoint = &v1alpha1.PeerEndpoint{
IP: peer.Endpoint.IP.String(),
Port: peer.Endpoint.Port,
}
}
p.Spec.PersistentKeepalive = peer.PersistentKeepalive
p.Spec.PublicKey = string(peer.PublicKey)
if _, err = pb.client.KiloV1alpha1().Peers().Update(p); err != nil {
return fmt.Errorf("failed to update peer: %v", err)
}
return nil
}
// Watch returns a chan of peer events.
func (pb *peerBackend) Watch() <-chan *mesh.PeerEvent {
return pb.events
}
func normalizeIP(ip string) *net.IPNet {
i, ipNet, err := net.ParseCIDR(ip)
if err != nil || ipNet == nil {
return nil
}
if ip4 := i.To4(); ip4 != nil {
ipNet.IP = ip4
return ipNet
}
ipNet.IP = i.To16()
return ipNet
}
func parseEndpoint(endpoint string) *wireguard.Endpoint {
if len(endpoint) == 0 {
return nil
}
parts := strings.Split(endpoint, ":")
if len(parts) < 2 {
return nil
}
portRaw := parts[len(parts)-1]
hostRaw := strings.Trim(strings.Join(parts[:len(parts)-1], ":"), "[]")
port, err := strconv.ParseUint(portRaw, 10, 32)
if err != nil {
return nil
}
if len(validation.IsValidPortNum(int(port))) != 0 {
return nil
}
ip := net.ParseIP(hostRaw)
if ip == nil {
if len(validation.IsDNS1123Subdomain(hostRaw)) == 0 {
return &wireguard.Endpoint{DNSOrIP: wireguard.DNSOrIP{DNS: hostRaw}, Port: uint32(port)}
}
return nil
}
if ip4 := ip.To4(); ip4 != nil {
ip = ip4
} else {
ip = ip.To16()
}
return &wireguard.Endpoint{DNSOrIP: wireguard.DNSOrIP{IP: ip}, Port: uint32(port)}
}