From 4f42a9b76b2ca2c261a4afec986b9518a61626ee Mon Sep 17 00:00:00 2001 From: Andy Pan Date: Sat, 21 Nov 2020 14:48:26 +0800 Subject: [PATCH] net: add note about disabling loopback in ListenMulticastUDP() Fixes #41752 Change-Id: I83520d2303e5fd2e5f6329f092b40e73c13771a1 Reviewed-on: https://go-review.googlesource.com/c/go/+/271908 Reviewed-by: Ian Lance Taylor Trust: Dmitri Shuralyov --- src/net/udpsock.go | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/net/udpsock.go b/src/net/udpsock.go index ec2bcfa607..571e099abd 100644 --- a/src/net/udpsock.go +++ b/src/net/udpsock.go @@ -259,6 +259,9 @@ func ListenUDP(network string, laddr *UDPAddr) (*UDPConn, error) { // ListenMulticastUDP is just for convenience of simple, small // applications. There are golang.org/x/net/ipv4 and // golang.org/x/net/ipv6 packages for general purpose uses. +// +// Note that ListenMulticastUDP will set the IP_MULTICAST_LOOP socket option +// to 0 under IPPROTO_IP, to disable loopback of multicast packets. func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) { switch network { case "udp", "udp4", "udp6": -- 2.50.0