From bef5767f37cfe42b1cf1ae60f01cfb4e16a7a2b8 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Tue, 17 Apr 2018 23:18:46 -0700 Subject: tcp: better delivery accounting for SYN-ACK and SYN-data the tcp_sock:delivered has inconsistent accounting for SYN and FIN. 1. it counts pure FIN 2. it counts pure SYN 3. it counts SYN-data twice 4. it does not count SYN-ACK For congestion control perspective it does not matter much as C.C. only cares about the difference not the aboslute value. But the next patch would export this field to user-space so it's better to report the absolute value w/o these caveats. This patch counts SYN, SYN-ACK, or SYN-data delivery once always in the "delivered" field. Signed-off-by: Yuchung Cheng Reviewed-by: Neal Cardwell Reviewed-by: Soheil Hassas Yeganeh Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 10 +++++++--- 1 file changed, 7 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 f93687f97d80..2499248d4a67 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5567,9 +5567,12 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, return true; } tp->syn_data_acked = tp->syn_data; - if (tp->syn_data_acked) - NET_INC_STATS(sock_net(sk), - LINUX_MIB_TCPFASTOPENACTIVE); + if (tp->syn_data_acked) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVE); + /* SYN-data is counted as two separate packets in tcp_ack() */ + if (tp->delivered > 1) + --tp->delivered; + } tcp_fastopen_add_skb(sk, synack); @@ -5901,6 +5904,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) } switch (sk->sk_state) { case TCP_SYN_RECV: + tp->delivered++; /* SYN-ACK delivery isn't tracked in tcp_ack */ if (!tp->srtt_us) tcp_synack_rtt_meas(sk, req); -- cgit v1.2.3