Fix interface lookup error on Android mobile platforms

On Android, InterfaceByName can fail due to SELinux restrictions, but
for link-local addresses with zone identifiers, the zone is sufficient
for routing and we can proceed without source binding. This fixes the
'interface wlan0 not found' error during multicast peer discovery.

Author: DrewCyber

src/core/link_tcp.go

@@ -69,13 +69,24 @@ func (l *linkTCP) dialerFor(dst *net.TCPAddr, sintf string) (*net.Dialer, error)
 		dialer.Control = l.getControl(sintf)
 		ief, err := net.InterfaceByName(sintf)
 		if err != nil {
+			// On mobile platforms (Android/iOS), InterfaceByName may fail due to
+			// permission restrictions (SELinux on Android), but for link-local
+			// addresses with zone identifiers, the zone is sufficient for routing
+			// and we can proceed without source binding
+			if dst.IP.IsLinkLocalUnicast() && dst.Zone != "" {
+				return dialer, nil
+			}
 			return nil, fmt.Errorf("interface %q not found", sintf)
 		}
 		if ief.Flags&net.FlagUp == 0 {
 			return nil, fmt.Errorf("interface %q is not up", sintf)
 		}
 		addrs, err := ief.Addrs()
 		if err != nil {
+			// Same mobile platform handling for address lookup failures
+			if dst.IP.IsLinkLocalUnicast() && dst.Zone != "" {
+				return dialer, nil
+			}
 			return nil, fmt.Errorf("interface %q addresses not available: %w", sintf, err)
 		}
 		for addrindex, addr := range addrs {