From: Eric Dumazet Date: Sun, 6 Mar 2016 17:29:21 +0000 (-0800) Subject: tcp: fix tcpi_segs_in after connection establishment X-Git-Tag: firefly_0821_release~176^2~4^2~49^2~96 X-Git-Url: http://plrg.eecs.uci.edu/git/?p=firefly-linux-kernel-4.4.55.git;a=commitdiff_plain;h=36b9c7cc09fc6d90e155f322f3f1d6fd3f53b0b7 tcp: fix tcpi_segs_in after connection establishment [ Upstream commit a9d99ce28ed359d68cf6f3c1a69038aefedf6d6a ] If final packet (ACK) of 3WHS is lost, it appears we do not properly account the following incoming segment into tcpi_segs_in While we are at it, starts segs_in with one, to count the SYN packet. We do not yet count number of SYN we received for a request sock, we might add this someday. packetdrill script showing proper behavior after fix : // Tests tcpi_segs_in when 3rd packet (ACK) of 3WHS is lost 0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +0 < S 0:0(0) win 32792 +0 > S. 0:0(0) ack 1 +.020 < P. 1:1001(1000) ack 1 win 32792 +0 accept(3, ..., ...) = 4 +.000 %{ assert tcpi_segs_in == 2, 'tcpi_segs_in=%d' % tcpi_segs_in }% Fixes: 2efd055c53c06 ("tcp: add tcpi_segs_in and tcpi_segs_out to tcp_info") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index ac6b1961ffeb..9475a2748a9a 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -458,7 +458,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk, newtp->rcv_wup = newtp->copied_seq = newtp->rcv_nxt = treq->rcv_isn + 1; - newtp->segs_in = 0; + newtp->segs_in = 1; newtp->snd_sml = newtp->snd_una = newtp->snd_nxt = newtp->snd_up = treq->snt_isn + 1; @@ -818,6 +818,7 @@ int tcp_child_process(struct sock *parent, struct sock *child, int ret = 0; int state = child->sk_state; + tcp_sk(child)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs); if (!sock_owned_by_user(child)) { ret = tcp_rcv_state_process(child, skb); /* Wakeup parent, send SIGIO */