ede3118cc8
Since #116 implemented fragile comparisons of iptables rules to avoid calling the iptables binary excessively during every reconciliation, the iptables rules for IPIP encapsulation must be updated to match the expected output. One complication is that rather than returning the protocol number in the rule, iptables resolves the protocol number to a name by looking up the number in the netd protocols database. This name can vary depending on the host's environment. This commit adds two solutions for resolving the protocol name: 1. a fixed mapping to the string `ipencap`, which should always work for Kilo whenever it runs in the Alpine Linux container; and 2. a runtime lookup using the netd database, which only works if Kilo is compiled with CGO and is meant to be used only if Kilo is not running in the normal container environment. Signed-off-by: Lucas Servén Marín <lserven@gmail.com>
95 lines
3.2 KiB
Go
95 lines
3.2 KiB
Go
// Copyright 2019 the Kilo authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package encapsulation
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import (
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"fmt"
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"net"
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"github.com/squat/kilo/pkg/iproute"
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"github.com/squat/kilo/pkg/iptables"
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)
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type ipip struct {
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iface int
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strategy Strategy
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}
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// NewIPIP returns an encapsulator that uses IPIP.
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func NewIPIP(strategy Strategy) Encapsulator {
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return &ipip{strategy: strategy}
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}
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// CleanUp will remove any created IPIP devices.
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func (i *ipip) CleanUp() error {
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if err := iproute.DeleteAddresses(i.iface); err != nil {
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return nil
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}
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return iproute.RemoveInterface(i.iface)
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}
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// Gw returns the correct gateway IP associated with the given node.
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func (i *ipip) Gw(_, internal net.IP, _ *net.IPNet) net.IP {
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return internal
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}
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// Index returns the index of the IPIP interface.
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func (i *ipip) Index() int {
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return i.iface
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}
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// Init initializes the IPIP interface.
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func (i *ipip) Init(base int) error {
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iface, err := iproute.NewIPIP(base)
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if err != nil {
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return fmt.Errorf("failed to create tunnel interface: %v", err)
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}
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if err := iproute.Set(iface, true); err != nil {
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return fmt.Errorf("failed to set tunnel interface up: %v", err)
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}
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i.iface = iface
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return nil
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}
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// Rules returns a set of iptables rules that are necessary
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// when traffic between nodes must be encapsulated.
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func (i *ipip) Rules(nodes []*net.IPNet) []iptables.Rule {
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var rules []iptables.Rule
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proto := ipipProtocolName()
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rules = append(rules, iptables.NewIPv4Chain("filter", "KILO-IPIP"))
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rules = append(rules, iptables.NewIPv6Chain("filter", "KILO-IPIP"))
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rules = append(rules, iptables.NewIPv4Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: jump to IPIP chain", "-j", "KILO-IPIP"))
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rules = append(rules, iptables.NewIPv6Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: jump to IPIP chain", "-j", "KILO-IPIP"))
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for _, n := range nodes {
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// Accept encapsulated traffic from peers.
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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"))
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}
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// Drop all other IPIP traffic.
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rules = append(rules, iptables.NewIPv4Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: reject other IPIP traffic", "-j", "DROP"))
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rules = append(rules, iptables.NewIPv6Rule("filter", "INPUT", "-p", proto, "-m", "comment", "--comment", "Kilo: reject other IPIP traffic", "-j", "DROP"))
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return rules
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}
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// Set sets the IP address of the IPIP interface.
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func (i *ipip) Set(cidr *net.IPNet) error {
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return iproute.SetAddress(i.iface, cidr)
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}
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// Strategy returns the configured strategy for encapsulation.
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func (i *ipip) Strategy() Strategy {
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return i.strategy
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}
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