tcp: account SYN-ACK timeouts & retransmissions

Currently we don't increment SYN-ACK timeouts & retransmissions
although we do increment the same stats for SYN. We seem to have lost
the SYN-ACK accounting with the introduction of tcp_syn_recv_timer
(commit 2248761e in the netdev-vger-cvs tree).

This patch fixes this issue. In the process we also rename the v4/v6
syn/ack retransmit functions for clarity. We also add a new
request_socket operations (syn_ack_timeout) so we can keep code in
inet_connection_sock.c protocol agnostic.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 8 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 382f667238ec..356f544c4c10 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -742,9 +742,9 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
  *      This still operates on a request_sock only, not on a big
  *      socket.
  */
-static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
-                                struct request_sock *req,
-                                struct request_values *rvp)
+static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
+                              struct request_sock *req,
+                              struct request_values *rvp)
 {
         const struct inet_request_sock *ireq = inet_rsk(req);
         int err = -1;
@@ -775,10 +775,11 @@ static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
         return err;
 }
 
-static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
+static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
                               struct request_values *rvp)
 {
-        return __tcp_v4_send_synack(sk, NULL, req, rvp);
+        TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
+        return tcp_v4_send_synack(sk, NULL, req, rvp);
 }
 
 /*
@@ -1192,10 +1193,11 @@ static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
         .family         =       PF_INET,
         .obj_size       =       sizeof(struct tcp_request_sock),
-        .rtx_syn_ack    =       tcp_v4_send_synack,
+        .rtx_syn_ack    =       tcp_v4_rtx_synack,
         .send_ack       =       tcp_v4_reqsk_send_ack,
         .destructor     =       tcp_v4_reqsk_destructor,
         .send_reset     =       tcp_v4_send_reset,
+        .syn_ack_timeout =      tcp_syn_ack_timeout,
 };
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -1373,8 +1375,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
         }
         tcp_rsk(req)->snt_isn = isn;
 
-        if (__tcp_v4_send_synack(sk, dst, req,
-                                 (struct request_values *)&tmp_ext) ||
+        if (tcp_v4_send_synack(sk, dst, req,
+                               (struct request_values *)&tmp_ext) ||
             want_cookie)
                 goto drop_and_free;