deduplicate relays

control_tester.go

@@ -70,7 +70,7 @@ func (c *Control) InjectRelays(vpnIp netip.Addr, relayVpnIps []netip.Addr) {
 	defer remoteList.Unlock()
 	c.f.lightHouse.Unlock()
 
-	remoteList.unlockedSetRelay(vpnIp, vpnIp, relayVpnIps)
+	remoteList.unlockedSetRelay(vpnIp, relayVpnIps)
 }
 
 // GetFromTun will pull a packet off the tun side of nebula

lighthouse.go

@@ -1222,7 +1222,7 @@ func (lhh *LightHouseHandler) handleHostQueryReply(n *NebulaMeta, fromVpnAddrs [
 		}
 	}
 
-	am.unlockedSetRelay(fromVpnAddrs[0], certVpnAddr, relays)
+	am.unlockedSetRelay(fromVpnAddrs[0], relays)
 	am.Unlock()
 
 	// Non-blocking attempt to trigger, skip if it would block
@@ -1286,7 +1286,7 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 		}
 	}
 
-	am.unlockedSetRelay(fromVpnAddrs[0], detailsVpnAddr, relays)
+	am.unlockedSetRelay(fromVpnAddrs[0], relays)
 	am.Unlock()
 
 	n = lhh.resetMeta()

remote_list.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net"
 	"net/netip"
+	"slices"
 	"sort"
 	"strconv"
 	"sync"
@@ -429,7 +430,7 @@ func (r *RemoteList) unlockedSetV4(ownerVpnIp, vpnIp netip.Addr, to []*V4AddrPor
 	}
 }
 
-func (r *RemoteList) unlockedSetRelay(ownerVpnIp, vpnIp netip.Addr, to []netip.Addr) {
+func (r *RemoteList) unlockedSetRelay(ownerVpnIp netip.Addr, to []netip.Addr) {
 	r.shouldRebuild = true
 	c := r.unlockedGetOrMakeRelay(ownerVpnIp)
 
@@ -595,6 +596,21 @@ func (r *RemoteList) unlockedCollect() {
 
 // unlockedSort assumes you have the write lock and performs the deduping and sorting of the address list
 func (r *RemoteList) unlockedSort(preferredRanges []netip.Prefix) {
+	// Use a map to deduplicate any relay addresses
+	dedupedRelays := map[netip.Addr]struct{}{}
+	for _, relay := range r.relays {
+		dedupedRelays[relay] = struct{}{}
+	}
+	r.relays = r.relays[:0]
+	for relay := range dedupedRelays {
+		r.relays = append(r.relays, relay)
+	}
+	// Put them in a somewhat consistent order after de-duplication
+	slices.SortFunc(r.relays, func(a, b netip.Addr) int {
+		return a.Compare(b)
+	})
+
+	// Now the addrs
 	n := len(r.addrs)
 	if n < 2 {
 		return

remote_list_test.go

@@ -41,6 +41,16 @@ func TestRemoteList_Rebuild(t *testing.T) {
 		func(netip.Addr, *V6AddrPort) bool { return true },
 	)
 
+	rl.unlockedSetRelay(
+		netip.MustParseAddr("0.0.0.1"),
+		[]netip.Addr{
+			netip.MustParseAddr("1::1"),
+			netip.MustParseAddr("1.2.3.4"),
+			netip.MustParseAddr("1.2.3.4"),
+			netip.MustParseAddr("1::1"),
+		},
+	)
+
 	rl.Rebuild([]netip.Prefix{})
 	assert.Len(t, rl.addrs, 10, "addrs contains too many entries")
 
@@ -76,6 +86,11 @@ func TestRemoteList_Rebuild(t *testing.T) {
 	assert.Equal(t, "[1::1]:2", rl.addrs[8].String())
 	assert.Equal(t, "[1:100::1]:1", rl.addrs[9].String())
 
+	// assert relay deduplicated
+	assert.Len(t, rl.relays, 2)
+	assert.Equal(t, "1.2.3.4", rl.relays[0].String())
+	assert.Equal(t, "1::1", rl.relays[1].String())
+
 	// Ensure we can hoist a specific ipv4 range over anything else
 	rl.Rebuild([]netip.Prefix{netip.MustParsePrefix("172.17.0.0/16")})
 	assert.Len(t, rl.addrs, 10, "addrs contains too many entries")