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Commit 7ad6848c authored by Octavian Purdila's avatar Octavian Purdila Committed by David S. Miller
Browse files

ip: fix mc_loop checks for tunnels with multicast outer addresses 



When we have L3 tunnels with different inner/outer families
(i.e. IPV4/IPV6) which use a multicast address as the outer tunnel
destination address, multicast packets will be loopbacked back to the
sending socket even if IP*_MULTICAST_LOOP is set to disabled.

The mc_loop flag is present in the family specific part of the socket
(e.g. the IPv4 or IPv4 specific part).  setsockopt sets the inner
family mc_loop flag. When the packet is pushed through the L3 tunnel
it will eventually be processed by the outer family which if different
will check the flag in a different part of the socket then it was set.

Signed-off-by: default avatarOctavian Purdila <opurdila@ixiacom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 58933c64

include/net/ip.h

+16 −0
Original line number Diff line number Diff line
@@ -326,6 +326,22 @@ static __inline__ void inet_reset_saddr(struct sock *sk) 


#endif



static inline int sk_mc_loop(struct sock *sk)

{

	if (!sk)

		return 1;

	switch (sk->sk_family) {

	case AF_INET:

		return inet_sk(sk)->mc_loop;

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

	case AF_INET6:

		return inet6_sk(sk)->mc_loop;

#endif

	}

	__WARN();

	return 1;

}



extern int	ip_call_ra_chain(struct sk_buff *skb);



/*

net/ipv4/ip_output.c

+1 −1
Original line number Diff line number Diff line
@@ -254,7 +254,7 @@ int ip_mc_output(struct sk_buff *skb) 
	 */



	if (rt->rt_flags&RTCF_MULTICAST) {

		if ((!sk || inet_sk(sk)->mc_loop)

		if (sk_mc_loop(sk)

#ifdef CONFIG_IP_MROUTE

		/* Small optimization: do not loopback not local frames,

		   which returned after forwarding; they will be  dropped

net/ipv6/ip6_output.c

+1 −2
Original line number Diff line number Diff line
@@ -121,10 +121,9 @@ static int ip6_output2(struct sk_buff *skb) 
	skb->dev = dev;



	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {

		struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;

		struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));



		if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&

		if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) &&

		    ((mroute6_socket(dev_net(dev)) &&

		     !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||

		     ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,