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authorYuchung Cheng <ycheng@google.com>2012-07-19 06:43:08 +0000
committerDavid S. Miller <davem@davemloft.net>2012-07-19 11:02:03 -0700
commit8e4178c1c7b52f7c99f5fd22ef7af6b2bff409e3 (patch)
tree101ec972d397346ea603ee2a08b8320f1ed690eb /net/ipv4
parent783237e8daf13481ee234997cbbbb823872ac388 (diff)
net-tcp: Fast Open client - receiving SYN-ACK
On receiving the SYN-ACK after SYN-data, the client needs to a) update the cached MSS and cookie (if included in SYN-ACK) b) retransmit the data not yet acknowledged by the SYN-ACK in the final ACK of the handshake. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_input.c40
1 files changed, 35 insertions, 5 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a06bb8959e7e..38b6a811edfc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5646,6 +5646,34 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
}
}
+static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
+ struct tcp_fastopen_cookie *cookie)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *data = tcp_write_queue_head(sk);
+ u16 mss = tp->rx_opt.mss_clamp;
+
+ if (mss == tp->rx_opt.user_mss) {
+ struct tcp_options_received opt;
+ const u8 *hash_location;
+
+ /* Get original SYNACK MSS value if user MSS sets mss_clamp */
+ tcp_clear_options(&opt);
+ opt.user_mss = opt.mss_clamp = 0;
+ tcp_parse_options(synack, &opt, &hash_location, 0, NULL);
+ mss = opt.mss_clamp;
+ }
+
+ tcp_fastopen_cache_set(sk, mss, cookie);
+
+ if (data) { /* Retransmit unacked data in SYN */
+ tcp_retransmit_skb(sk, data);
+ tcp_rearm_rto(sk);
+ return true;
+ }
+ return false;
+}
+
static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th, unsigned int len)
{
@@ -5653,9 +5681,10 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_cookie_values *cvp = tp->cookie_values;
+ struct tcp_fastopen_cookie foc = { .len = -1 };
int saved_clamp = tp->rx_opt.mss_clamp;
- tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, NULL);
+ tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, &foc);
if (th->ack) {
/* rfc793:
@@ -5665,11 +5694,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
* If SEG.ACK =< ISS, or SEG.ACK > SND.NXT, send
* a reset (unless the RST bit is set, if so drop
* the segment and return)"
- *
- * We do not send data with SYN, so that RFC-correct
- * test reduces to:
*/
- if (TCP_SKB_CB(skb)->ack_seq != tp->snd_nxt)
+ if (!after(TCP_SKB_CB(skb)->ack_seq, tp->snd_una) ||
+ after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt))
goto reset_and_undo;
if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
@@ -5781,6 +5808,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
tcp_finish_connect(sk, skb);
+ if (tp->syn_fastopen && tcp_rcv_fastopen_synack(sk, skb, &foc))
+ return -1;
+
if (sk->sk_write_pending ||
icsk->icsk_accept_queue.rskq_defer_accept ||
icsk->icsk_ack.pingpong) {