From 9c30ae8398b0813e237bde387d67a7f74ab2db2d Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Tue, 19 Jan 2021 11:26:19 -0800 Subject: tcp: fix TCP socket rehash stats mis-accounting The previous commit 32efcc06d2a1 ("tcp: export count for rehash attempts") would mis-account rehashing SNMP and socket stats: a. During handshake of an active open, only counts the first SYN timeout b. After handshake of passive and active open, stop updating after (roughly) TCP_RETRIES1 recurring RTOs c. After the socket aborts, over count timeout_rehash by 1 This patch fixes this by checking the rehash result from sk_rethink_txhash. Fixes: 32efcc06d2a1 ("tcp: export count for rehash attempts") Signed-off-by: Yuchung Cheng Signed-off-by: Eric Dumazet Signed-off-by: Neal Cardwell Link: https://lore.kernel.org/r/20210119192619.1848270-1-ycheng@google.com Signed-off-by: Jakub Kicinski --- net/ipv4/tcp_input.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index bafcab75f425..a7dfca0a38cd 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4397,10 +4397,9 @@ static void tcp_rcv_spurious_retrans(struct sock *sk, const struct sk_buff *skb) * The receiver remembers and reflects via DSACKs. Leverage the * DSACK state and change the txhash to re-route speculatively. */ - if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq) { - sk_rethink_txhash(sk); + if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq && + sk_rethink_txhash(sk)) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDUPLICATEDATAREHASH); - } } static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb) -- cgit v1.2.3