From daef52bab1fd26e24e8e9578f8fb33ba1d0cb412 Mon Sep 17 00:00:00 2001 From: Neal Cardwell Date: Sun, 12 Feb 2012 18:37:10 +0000 Subject: [PATCH] tcp: fix range tcp_shifted_skb() passes to tcp_sacktag_one() Fix the newly-SACKed range to be the range of newly-shifted bytes. Previously - since 832d11c5cd076abc0aa1eaf7be96c81d1a59ce41 - tcp_shifted_skb() incorrectly called tcp_sacktag_one() with the start and end sequence numbers of the skb it passes in set to the range just beyond the range that is newly-SACKed. This commit also removes a special-case adjustment to lost_cnt_hint in tcp_shifted_skb() since the pre-existing adjustment of lost_cnt_hint in tcp_sacktag_one() now properly handles this things now that the correct start sequence number is passed in. Signed-off-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 4e8a81fda65c..8116d06e042c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1388,6 +1388,9 @@ static u8 tcp_sacktag_one(struct sock *sk, return sacked; } +/* Shift newly-SACKed bytes from this skb to the immediately previous + * already-SACKed sk_buff. Mark the newly-SACKed bytes as such. + */ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, struct tcp_sacktag_state *state, unsigned int pcount, int shifted, int mss, @@ -1395,12 +1398,11 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *prev = tcp_write_queue_prev(sk, skb); + u32 start_seq = TCP_SKB_CB(skb)->seq; /* start of newly-SACKed */ + u32 end_seq = start_seq + shifted; /* end of newly-SACKed */ BUG_ON(!pcount); - if (skb == tp->lost_skb_hint) - tp->lost_cnt_hint += pcount; - TCP_SKB_CB(prev)->end_seq += shifted; TCP_SKB_CB(skb)->seq += shifted; @@ -1424,12 +1426,11 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, skb_shinfo(skb)->gso_type = 0; } - /* We discard results */ - tcp_sacktag_one(sk, state, - TCP_SKB_CB(skb)->sacked, - TCP_SKB_CB(skb)->seq, - TCP_SKB_CB(skb)->end_seq, - dup_sack, pcount); + /* Adjust counters and hints for the newly sacked sequence range but + * discard the return value since prev is already marked. + */ + tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked, + start_seq, end_seq, dup_sack, pcount); /* Difference in this won't matter, both ACKed by the same cumul. ACK */ TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS); -- 2.20.1