From 0dde7b5404a3d52dcd9ce66d46197f6c3ca97dda Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Thu, 20 Sep 2007 11:28:05 -0700 Subject: [PATCH] [TCP]: Maintain highest_sack accurately to the highest skb MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit In general, it should not be necessary to call tcp_fragment for already SACKed skbs, but it's better to be safe than sorry. And indeed, it can be called from sacktag when a DSACK arrives or some ACK (with SACK) reordering occurs (sacktag could be made to avoid the call in the latter case though I'm not sure if it's worth of the trouble and added complexity to cover such marginal case). The collapse case has return for SACKED_ACKED case earlier, so just WARN_ON if internal inconsistency is detected for some reason. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index d65d17bb2a0..9df5b2a4da6 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -692,6 +692,9 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq; TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq; + if (tp->sacked_out && (TCP_SKB_CB(skb)->seq == tp->highest_sack)) + tp->highest_sack = TCP_SKB_CB(buff)->seq; + /* PSH and FIN should only be set in the second packet. */ flags = TCP_SKB_CB(skb)->flags; TCP_SKB_CB(skb)->flags = flags & ~(TCPCB_FLAG_FIN|TCPCB_FLAG_PSH); @@ -1723,6 +1726,10 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m /* Update sequence range on original skb. */ TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(next_skb)->end_seq; + if (WARN_ON(tp->sacked_out && + (TCP_SKB_CB(next_skb)->seq == tp->highest_sack))) + return; + /* Merge over control information. */ flags |= TCP_SKB_CB(next_skb)->flags; /* This moves PSH/FIN etc. over */ TCP_SKB_CB(skb)->flags = flags; -- 2.41.1