From 0709c4dac0017886b9854829b681b7be2d4046d0 Mon Sep 17 00:00:00 2001
From: jdl <jdl@private.local>
Date: Sat, 13 Jun 2026 15:37:35 +0200
Subject: [PATCH] Audit changes.

---
 peer/multicast/broadcaster.go |  2 +-
 peer/multicast/receiver.go    | 15 +++++++++++----
 peer/new.go                   |  2 +-
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/peer/multicast/broadcaster.go b/peer/multicast/broadcaster.go
index 3acfa2d..4abce0c 100644
--- a/peer/multicast/broadcaster.go
+++ b/peer/multicast/broadcaster.go
@@ -26,7 +26,7 @@ func Broadcast(
 }
 
 func broadcastInner(selfVPNIP netip.Addr, pubKey wgtypes.Key, wgPort uint16, signKey *[64]byte) {
-	conn, err := net.ListenMulticastUDP("udp", nil, addr)
+	conn, err := net.ListenMulticastUDP("udp", nil, multicastAddr(selfVPNIP))
 	if err != nil {
 		log.Printf("[MCBroadcast] bind: %v", err)
 		return
diff --git a/peer/multicast/receiver.go b/peer/multicast/receiver.go
index 4dcdf69..91c032c 100644
--- a/peer/multicast/receiver.go
+++ b/peer/multicast/receiver.go
@@ -9,19 +9,19 @@ import (
 	"time"
 )
 
-func Receiver(vpnNet netip.Prefix, selfVPNIP netip.Addr, ch chan<- Packet) {
+func Receiver(selfVPNIP netip.Addr, ch chan<- Packet) {
 	for {
-		if err := receiver(vpnNet, selfVPNIP, ch); err != nil {
+		if err := receiver(selfVPNIP, ch); err != nil {
 			log.Printf("[MCReader] %v", err)
 		}
 		time.Sleep(errorTimeout)
 	}
 }
 
-func receiver(vpnNet netip.Prefix, selfVPNIP netip.Addr, ch chan<- Packet) error {
+func receiver(selfVPNIP netip.Addr, ch chan<- Packet) error {
 	selfIP := selfVPNIP.As4()[3]
 
-	conn, err := net.ListenMulticastUDP("udp", nil, addr)
+	conn, err := net.ListenMulticastUDP("udp", nil, multicastAddr(selfVPNIP))
 	if err != nil {
 		return fmt.Errorf("bind: %w", err)
 	}
@@ -59,3 +59,10 @@ func receiver(vpnNet netip.Prefix, selfVPNIP netip.Addr, ch chan<- Packet) error
 		ch <- packet
 	}
 }
+
+func multicastAddr(vpnIP netip.Addr) *net.UDPAddr {
+	b := vpnIP.As4()
+	return net.UDPAddrFromAddrPort(
+		netip.AddrPortFrom(
+			netip.AddrFrom4([4]byte{239, b[1], b[2], 0}), 4560))
+}
diff --git a/peer/new.go b/peer/new.go
index ff75168..3c008bb 100644
--- a/peer/new.go
+++ b/peer/new.go
@@ -81,7 +81,7 @@ func New(
 
 	if !state.IsPublic {
 		go multicast.Broadcast(state.VPNIP, state.PrivKey.PublicKey(), state.WGPort, &state.SignKey)
-		go multicast.Receiver(state.VPNNet, state.VPNIP, multicastCh)
+		go multicast.Receiver(state.VPNIP, multicastCh)
 	}
 
 	return &App{