Commit 850dcc4d authored Oct 07, 2015 by Eric W. Biederman Committed by David S. Miller Oct 08, 2015

ipv4: Fix ip_queue_xmit to pass sk into ip_local_out_sk



After a packet has been encapsulated by a tunnel we should use the
tunnel sockets local multicast loopback flag to control if the
encapsulated packet should be locally loopback back.

Pass sk into ip_local_out_sk so that in the rare case we are dealing
with a tunneled packet whose tunnel destination address is a multicast
address the kernel properly decides to loopback this packet.

In practice I don't think this matters as ip_queue_xmit is used by
tcp, l2tp and sctp none of which I am aware of uses ip level
multicasting as they are all point to point communications protocols.
Let's fix this before someone uses ip_queue_xmit for a tunnel protocol
that does use multicast.

Fixes: aad88724 ("ipv4: add a sock pointer to dst->output() path.")
Fixes: b0270e91 ("ipv4: add a sock pointer to ip_queue_xmit()")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent fd2874b3

net/ipv4/ip_output.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -460,7 +460,7 @@ packet_routed:
		skb->priority = sk->sk_priority;
		skb->mark = sk->sk_mark;

		res = ip_local_out(skb);
		res = ip_local_out_sk(sk, skb);
		rcu_read_unlock();
		return res;

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