Filter out link local and dont send the port

network/localendpoints.go

@@ -4,7 +4,6 @@ import (
 	"net"
 	"regexp"
 	"sort"
-	"strconv"
 
 	"github.com/fosrl/newt/logger"
 )
@@ -66,10 +65,9 @@ var (
 )
 
 const (
-	scorePhysical  = 0
-	scoreUnknown   = 10
-	scoreVirtual   = 20
-	scoreLinkLocal = 1000
+	scorePhysical = 0
+	scoreUnknown  = 10
+	scoreVirtual  = 20
 )
 
 // interfaceScore ranks an interface name by how likely it is to be a
@@ -88,9 +86,9 @@ func interfaceScore(name string) int {
 	return scoreUnknown
 }
 
-// GetLocalEndpoints returns "ip:port" strings (bracketed for IPv6, e.g.
-// "[fe80::1]:51820") for every usable, non-loopback IP address bound to a
-// network interface on this host. The list is ordered with interfaces most
+// GetLocalEndpoints returns IP address strings for every usable,
+// non-loopback IP address bound to a network interface on this host. The
+// list is ordered with interfaces most
 // likely to be a genuine host network (wired/Wi-Fi) first, and interfaces
 // that are typically synthetic (Docker, VPN tunnels, hypervisor bridges,
 // etc.) last, so callers should try the results roughly in order.
@@ -101,7 +99,7 @@ func interfaceScore(name string) int {
 //
 // If interfaces cannot be enumerated (e.g. insufficient OS permissions),
 // an info message is logged and an empty slice is returned.
-func GetLocalEndpoints(port uint16, excludeInterface string) []string {
+func GetLocalEndpoints(excludeInterface string) []string {
 	ifaces, err := net.Interfaces()
 	if err != nil {
 		logger.Info("Unable to enumerate local network interfaces, localEndpoints will not be reported: %v", err)
@@ -141,13 +139,14 @@ func GetLocalEndpoints(port uint16, excludeInterface string) []string {
 			if ip == nil || ip.IsLoopback() || ip.IsUnspecified() {
 				continue
 			}
-
-			score := baseScore
 			if ip.IsLinkLocalUnicast() || ip.IsLinkLocalMulticast() {
-				score += scoreLinkLocal
+				// Link-local addresses (169.254.0.0/16, fe80::/10) aren't
+				// routable off the local segment, so they're never a
+				// reachable endpoint for a peer.
+				continue
 			}
 
-			candidates = append(candidates, candidate{score: score, ip: ip.String()})
+			candidates = append(candidates, candidate{score: baseScore, ip: ip.String()})
 		}
 	}
 
@@ -155,10 +154,9 @@ func GetLocalEndpoints(port uint16, excludeInterface string) []string {
 		return candidates[i].score < candidates[j].score
 	})
 
-	portStr := strconv.Itoa(int(port))
 	endpoints := make([]string, 0, len(candidates))
 	for _, c := range candidates {
-		endpoints = append(endpoints, net.JoinHostPort(c.ip, portStr))
+		endpoints = append(endpoints, c.ip)
 	}
 	return endpoints
 }

newt/clients.go

@@ -103,11 +103,11 @@ func (n *Newt) clientsOnConnect() {
 	}
 }
 
-// localEndpoints returns "ip:port" candidates on this host that could
+// localEndpoints returns candidate IP addresses on this host that could
 // potentially be used to reach our WireGuard listen port, ranked with the
 // most likely genuine host interfaces first.
 func (n *Newt) localEndpoints() []string {
-	return network.GetLocalEndpoints(n.config.Port, n.config.InterfaceName)
+	return network.GetLocalEndpoints(n.config.InterfaceName)
 }
 
 func (n *Newt) clientsStartDirectRelay(tunnelIP string) {