From c00779c7d3959ddad37ab63923aad567afb176fb Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Sun, 29 Sep 2024 20:58:10 +0100
Subject: [PATCH] Multicast interface detection and shutdown tweaks

May help with #1173.
---
 src/core/link.go           | 5 ++++-
 src/multicast/multicast.go | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/core/link.go b/src/core/link.go
index 2eb480d2..4a8df538 100644
--- a/src/core/link.go
+++ b/src/core/link.go
@@ -422,7 +422,10 @@ func (l *links) listen(u *url.URL, sintf string) (*Listener, error) {
 	li := &Listener{
 		listener: listener,
 		ctx:      ctx,
-		Cancel:   cancel,
+		Cancel: func() {
+			cancel()
+			_ = listener.Close()
+		},
 	}
 
 	var options linkOptions
diff --git a/src/multicast/multicast.go b/src/multicast/multicast.go
index 902d7729..32f5dcad 100644
--- a/src/multicast/multicast.go
+++ b/src/multicast/multicast.go
@@ -190,6 +190,8 @@ func (m *Multicast) _getAllowedInterfaces() map[string]*interfaceInfo {
 		switch {
 		case iface.Flags&net.FlagUp == 0:
 			continue // Ignore interfaces that are down
+		case iface.Flags&net.FlagRunning == 0:
+			continue // Ignore interfaces that are not running
 		case iface.Flags&net.FlagMulticast == 0:
 			continue // Ignore non-multicast interfaces
 		case iface.Flags&net.FlagPointToPoint != 0: