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authorNeal Cardwell <ncardwell@google.com>2012-09-22 04:18:55 +0000
committerDavid S. Miller <davem@davemloft.net>2012-09-22 15:47:10 -0400
commit016818d076871c4ee34db1e8d74dc17ac1de626a (patch)
tree60d0f20afb0937f61b5fc4611e53a2ac411a0646 /net/ipv4
parent623df484a777f3c00c1ea3d6a7565b8d8ac688a1 (diff)
tcp: TCP Fast Open Server - take SYNACK RTT after completing 3WHS
When taking SYNACK RTT samples for servers using TCP Fast Open, fix the code to ensure that we only call tcp_valid_rtt_meas() after we receive the ACK that completes the 3-way handshake. Previously we were always taking an RTT sample in tcp_v4_syn_recv_sock(). However, for TCP Fast Open connections tcp_v4_conn_req_fastopen() calls tcp_v4_syn_recv_sock() at the time we receive the SYN. So for TFO we must wait until tcp_rcv_state_process() to take the RTT sample. To fix this, we wait until after TFO calls tcp_v4_syn_recv_sock() before we set the snt_synack timestamp, since tcp_synack_rtt_meas() already ensures that we only take a SYNACK RTT sample if snt_synack is non-zero. To be careful, we only take a snt_synack timestamp when a SYNACK transmit or retransmit succeeds. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_input.c1
-rw-r--r--net/ipv4/tcp_ipv4.c12
2 files changed, 10 insertions, 3 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e2bec815ff23..bb326684495b 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5983,6 +5983,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
* need req so release it.
*/
if (req) {
+ tcp_synack_rtt_meas(sk, req);
reqsk_fastopen_remove(sk, req, false);
} else {
/* Make sure socket is routed, for
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1e66f7fb4fe6..0a7e020f16b5 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -868,6 +868,8 @@ static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
ireq->rmt_addr,
ireq->opt);
err = net_xmit_eval(err);
+ if (!tcp_rsk(req)->snt_synack && !err)
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
}
return err;
@@ -1382,6 +1384,7 @@ static int tcp_v4_conn_req_fastopen(struct sock *sk,
struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
const struct inet_request_sock *ireq = inet_rsk(req);
struct sock *child;
+ int err;
req->retrans = 0;
req->sk = NULL;
@@ -1393,8 +1396,11 @@ static int tcp_v4_conn_req_fastopen(struct sock *sk,
kfree_skb(skb_synack);
return -1;
}
- ip_build_and_send_pkt(skb_synack, sk, ireq->loc_addr,
- ireq->rmt_addr, ireq->opt);
+ err = ip_build_and_send_pkt(skb_synack, sk, ireq->loc_addr,
+ ireq->rmt_addr, ireq->opt);
+ err = net_xmit_eval(err);
+ if (!err)
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
/* XXX (TFO) - is it ok to ignore error and continue? */
spin_lock(&queue->fastopenq->lock);
@@ -1612,7 +1618,6 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
isn = tcp_v4_init_sequence(skb);
}
tcp_rsk(req)->snt_isn = isn;
- tcp_rsk(req)->snt_synack = tcp_time_stamp;
if (dst == NULL) {
dst = inet_csk_route_req(sk, &fl4, req);
@@ -1650,6 +1655,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
if (err || want_cookie)
goto drop_and_free;
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
tcp_rsk(req)->listener = NULL;
/* Add the request_sock to the SYN table */
inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);