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pkg: deduplicate peer IP addresses

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We need to defensively deduplicate peer allowed IPs.
If two peers claim the same IP, the WireGuard configuration
could flap, causing the interface to churn.
This commit is contained in:
Lucas Servén Marín 2019-05-10 02:07:05 +02:00
parent 4d9c203603
commit 35390054ba
No known key found for this signature in database
GPG Key ID: 586FEAF680DA74AD
4 changed files with 215 additions and 20 deletions
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49
cmd/kgctl/showconf.go
View File

@ -15,6 +15,7 @@
package main
import (
"bytes"
"errors"
"fmt"
"net"
@ -68,7 +69,7 @@ func showConf() *cobra.Command {
}
cmd.PersistentFlags().BoolVar(&showConfOpts.asPeer, "as-peer", false, "Should the resource be shown as a peer? Useful to configure this resource as a peer of another WireGuard interface.")
cmd.PersistentFlags().StringVarP(&showConfOpts.output, "output", "o", "wireguard", fmt.Sprintf("The output format of the resource. Only valid when combined with 'as-peer'. Possible values: %s", availableOutputFormats))
cmd.PersistentFlags().StringSliceVar(&allowedIPs, "allowed-ips", []string{}, "Override the allowed IPs of the configuration. Only valid when combined with 'as-peer'.")
cmd.PersistentFlags().StringSliceVar(&allowedIPs, "allowed-ips", []string{}, "Add the given IPs to the allowed IPs of the configuration. Only valid when combined with 'as-peer'.")
return cmd
}
@ -151,6 +152,18 @@ func runShowConfNode(_ *cobra.Command, args []string) error {
return fmt.Errorf("failed to create topology: %v", err)
}
var found bool
for _, p := range t.PeerConf("").Peers {
if bytes.Equal(p.PublicKey, nodes[hostname].Key) {
found = true
break
}
}
if !found {
_, err := os.Stderr.WriteString(fmt.Sprintf("Node %q is not a leader node\n", hostname))
return err
}
if !showConfOpts.asPeer {
c, err := t.Conf().Bytes()
if err != nil {
@ -164,17 +177,16 @@ func runShowConfNode(_ *cobra.Command, args []string) error {
case outputFormatJSON:
fallthrough
case outputFormatYAML:
p := translatePeer(t.AsPeer())
p.Name = hostname
if len(showConfOpts.allowedIPs) != 0 {
p.Spec.AllowedIPs = allowedIPs
}
return showConfOpts.serializer.Encode(p, os.Stdout)
p := t.AsPeer()
p.AllowedIPs = append(p.AllowedIPs, showConfOpts.allowedIPs...)
p.DeduplicateIPs()
k8sp := translatePeer(p)
k8sp.Name = hostname
return showConfOpts.serializer.Encode(k8sp, os.Stdout)
case outputFormatWireGuard:
p := t.AsPeer()
if len(showConfOpts.allowedIPs) != 0 {
p.AllowedIPs = showConfOpts.allowedIPs
}
p.AllowedIPs = append(p.AllowedIPs, showConfOpts.allowedIPs...)
p.DeduplicateIPs()
c, err := (&wireguard.Conf{
Peers: []*wireguard.Peer{p},
}).Bytes()
@ -241,17 +253,16 @@ func runShowConfPeer(_ *cobra.Command, args []string) error {
case outputFormatJSON:
fallthrough
case outputFormatYAML:
p := translatePeer(&peers[peer].Peer)
p.Name = peer
if len(showConfOpts.allowedIPs) != 0 {
p.Spec.AllowedIPs = allowedIPs
}
return showConfOpts.serializer.Encode(p, os.Stdout)
p := peers[peer]
p.AllowedIPs = append(p.AllowedIPs, showConfOpts.allowedIPs...)
p.DeduplicateIPs()
k8sp := translatePeer(&p.Peer)
k8sp.Name = peer
return showConfOpts.serializer.Encode(k8sp, os.Stdout)
case outputFormatWireGuard:
p := &peers[peer].Peer
if len(showConfOpts.allowedIPs) != 0 {
p.AllowedIPs = showConfOpts.allowedIPs
}
p.AllowedIPs = append(p.AllowedIPs, showConfOpts.allowedIPs...)
p.DeduplicateIPs()
c, err := (&wireguard.Conf{
Peers: []*wireguard.Peer{p},
}).Bytes()

28
pkg/mesh/topology.go
View File

@ -138,7 +138,9 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
sort.Slice(t.peers, func(i, j int) bool {
return t.peers[i].Name < t.peers[j].Name
})
// We need to defensively deduplicate peer allowed IPs. If two peers claim the same IP,
// the WireGuard configuration could flap, causing the interface to churn.
t.peers = deduplicatePeerIPs(t.peers)
// Allocate IPs to the segment leaders in a stable, coordination-free manner.
a := newAllocator(*subnet)
for _, segment := range t.segments {
@ -417,3 +419,27 @@ func findLeader(nodes []*Node) int {
}
return 0
}
func deduplicatePeerIPs(peers []*Peer) []*Peer {
ps := make([]*Peer, len(peers))
ips := make(map[string]struct{})
for i, peer := range peers {
p := Peer{
Name: peer.Name,
Peer: wireguard.Peer{
Endpoint: peer.Endpoint,
PersistentKeepalive: peer.PersistentKeepalive,
PublicKey: peer.PublicKey,
},
}
for _, ip := range peer.AllowedIPs {
if _, ok := ips[ip.String()]; ok {
continue
}
p.AllowedIPs = append(p.AllowedIPs, ip)
ips[ip.String()] = struct{}{}
}
ps[i] = &p
}
return ps
}

144
pkg/mesh/topology_test.go
View File

@ -1246,3 +1246,147 @@ func TestFindLeader(t *testing.T) {
}
}
}
func TestDeduplicatePeerIPs(t *testing.T) {
p1 := &Peer{
Name: "1",
Peer: wireguard.Peer{
PublicKey: []byte("key1"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.1"), Mask: net.CIDRMask(24, 32)},
{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(24, 32)},
},
},
}
p2 := &Peer{
Name: "2",
Peer: wireguard.Peer{
PublicKey: []byte("key2"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.1"), Mask: net.CIDRMask(24, 32)},
{IP: net.ParseIP("10.0.0.3"), Mask: net.CIDRMask(24, 32)},
},
},
}
p3 := &Peer{
Name: "3",
Peer: wireguard.Peer{
PublicKey: []byte("key3"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(24, 32)},
{IP: net.ParseIP("10.0.0.3"), Mask: net.CIDRMask(24, 32)},
{IP: net.ParseIP("10.0.0.1"), Mask: net.CIDRMask(24, 32)},
},
},
}
p4 := &Peer{
Name: "4",
Peer: wireguard.Peer{
PublicKey: []byte("key4"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.3"), Mask: net.CIDRMask(24, 32)},
{IP: net.ParseIP("10.0.0.3"), Mask: net.CIDRMask(24, 32)},
},
},
}
for _, tc := range []struct {
name string
peers []*Peer
out []*Peer
}{
{
name: "nil",
peers: nil,
out: nil,
},
{
name: "simple dupe",
peers: []*Peer{p1, p2},
out: []*Peer{
p1,
{
Name: "2",
Peer: wireguard.Peer{
PublicKey: []byte("key2"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.3"), Mask: net.CIDRMask(24, 32)},
},
},
},
},
},
{
name: "simple dupe reversed",
peers: []*Peer{p2, p1},
out: []*Peer{
p2,
{
Name: "1",
Peer: wireguard.Peer{
PublicKey: []byte("key1"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(24, 32)},
},
},
},
},
},
{
name: "one duplicates all",
peers: []*Peer{p3, p2, p1, p4},
out: []*Peer{
p3,
{
Name: "2",
Peer: wireguard.Peer{
PublicKey: []byte("key2"),
},
},
{
Name: "1",
Peer: wireguard.Peer{
PublicKey: []byte("key1"),
},
},
{
Name: "4",
Peer: wireguard.Peer{
PublicKey: []byte("key4"),
},
},
},
},
{
name: "one duplicates itself",
peers: []*Peer{p4, p1},
out: []*Peer{
{
Name: "4",
Peer: wireguard.Peer{
PublicKey: []byte("key4"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.3"), Mask: net.CIDRMask(24, 32)},
},
},
},
{
Name: "1",
Peer: wireguard.Peer{
PublicKey: []byte("key1"),
AllowedIPs: []*net.IPNet{
{IP: net.ParseIP("10.0.0.1"), Mask: net.CIDRMask(24, 32)},
{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(24, 32)},
},
},
},
},
},
} {
out := deduplicatePeerIPs(tc.peers)
if diff := pretty.Compare(out, tc.out); diff != "" {
t.Errorf("test case %q: got diff: %v", tc.name, diff)
}
}
}

14
pkg/wireguard/conf.go
View File

@ -59,6 +59,20 @@ type Peer struct {
PublicKey []byte
}
// DeduplicateIPs eliminates duplicate allowed IPs.
func (p *Peer) DeduplicateIPs() {
var ips []*net.IPNet
seen := make(map[string]struct{})
for _, ip := range p.AllowedIPs {
if _, ok := seen[ip.String()]; ok {
continue
}
ips = append(ips, ip)
seen[ip.String()] = struct{}{}
}
p.AllowedIPs = ips
}
// Endpoint represents an `endpoint` key of a `peer` section.
type Endpoint struct {
IP net.IP