Commit db8caf3d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

gro: should aggregate frames without DF 



GRO on IPv4 doesn't aggregate frames if they don't have DF bit set.

Some servers use IP_MTU_DISCOVER/IP_PMTUDISC_PROBE, so linux receivers
are unable to aggregate this kind of traffic.

The right thing to do is to allow aggregation as long as the DF bit has
same value on all segments.

bnx2x LRO does this correctly.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Jerry Chu <hkchu@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Reviewed-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c3f1dbaf

net/ipv4/af_inet.c

+2 −1
Original line number Diff line number Diff line
@@ -1385,7 +1385,7 @@ static struct sk_buff **inet_gro_receive(struct sk_buff **head, 
		goto out_unlock;



	id = ntohl(*(__be32 *)&iph->id);

	flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id ^ IP_DF));

	flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF));

	id >>= 16;



	for (p = *head; p; p = p->next) {
@@ -1407,6 +1407,7 @@ static struct sk_buff **inet_gro_receive(struct sk_buff **head, 
		NAPI_GRO_CB(p)->flush |=

			(iph->ttl ^ iph2->ttl) |

			(iph->tos ^ iph2->tos) |

			((iph->frag_off ^ iph2->frag_off) & htons(IP_DF)) |

			((u16)(ntohs(iph2->id) + NAPI_GRO_CB(p)->count) ^ id);



		NAPI_GRO_CB(p)->flush |= flush;

CRA Git | Maintained and supported by SUSTech CRA and CCSE