From ff9b5e0f08cb650d113eef0c654f931c0a7ae730 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 31 Aug 2006 15:11:02 -0700 Subject: [PATCH] [TCP]: Fix rcv mss estimate for LRO By passing a Linux-generated TSO packet straight back into Linux, Xen becomes our first LRO user :) Unfortunately, there is at least one spot in our stack that needs to be changed to cope with this. The receive MSS estimate is computed from the raw packet size. This is broken if the packet is GSO/LRO. Fortunately the real MSS can be found in gso_size so we simply need to use that if it is non-zero. Real LRO NICs should of course set the gso_size field in future. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index caf3c41dcc8c..511b738f118a 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -127,7 +127,7 @@ static void tcp_measure_rcv_mss(struct sock *sk, /* skb->len may jitter because of SACKs, even if peer * sends good full-sized frames. */ - len = skb->len; + len = skb_shinfo(skb)->gso_size ?: skb->len; if (len >= icsk->icsk_ack.rcv_mss) { icsk->icsk_ack.rcv_mss = len; } else { -- 2.39.5