Commit 03d56daa authored Sep 09, 2014 by Tom Herbert Committed by David S. Miller Sep 09, 2014

ipv6: Clear flush_id to make GRO work



In TCP gro we check flush_id which is derived from the IP identifier.
In IPv4 gro path the flush_id is set with the expectation that every
matched packet increments IP identifier. In IPv6, the flush_id is
never set and thus is uinitialized. What's worse is that in IPv6
over IPv4 encapsulation, the IP identifier is taken from the outer
header which is currently not incremented on every packet for Linux
stack, so GRO in this case never matches packets (identifier is
not increasing).

This patch clears flush_id for every time for a matched packet in
IPv6 gro_receive. We need to do this each time to overwrite the
setting that would be done in IPv4 gro_receive per the outer
header in IPv6 over Ipv4 encapsulation.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent fe3881cf

net/ipv6/ip6_offload.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -261,6 +261,9 @@ static struct sk_buff ipv6_gro_receive(struct sk_buff head,
		/* flush if Traffic Class fields are different */
		NAPI_GRO_CB(p)->flush \|= !!(first_word & htonl(0x0FF00000));
		NAPI_GRO_CB(p)->flush \|= flush;

		/* Clear flush_id, there's really no concept of ID in IPv6. */
		NAPI_GRO_CB(p)->flush_id = 0;
		}

		NAPI_GRO_CB(skb)->flush \|= flush;

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