Commit 355b7d7b authored Mar 04, 2016 by Bill Sommerfeld Committed by Sasha Levin Jul 12, 2016

udp6: fix UDP/IPv6 encap resubmit path



[ Upstream commit 59dca1d8a6725a121dae6c452de0b2611d5865dc ]

IPv4 interprets a negative return value from a protocol handler as a
request to redispatch to a new protocol.  In contrast, IPv6 interprets a
negative value as an error, and interprets a positive value as a request
for redispatch.

UDP for IPv6 was unaware of this difference.  Change __udp6_lib_rcv() to
return a positive value for redispatch.  Note that the socket's
encap_rcv hook still needs to return a negative value to request
dispatch, and in the case of IPv6 packets, adjust IP6CB(skb)->nhoff to
identify the byte containing the next protocol.

Signed-off-by: Bill Sommerfeld <wsommerfeld@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent 17c09e33

net/ipv6/udp.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -898,11 +898,9 @@ int __udp6_lib_rcv(struct sk_buff skb, struct udp_table udptable,
		ret = udpv6_queue_rcv_skb(sk, skb);
		sock_put(sk);

		/* a return value > 0 means to resubmit the input, but
		* it wants the return to be -protocol, or 0
		*/
		/* a return value > 0 means to resubmit the input */
		if (ret > 0)
		return -ret;
		return ret;

		return 0;
		}