From b5afe7bc71a1689376c9b547376d17568469f3b3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Sat, 20 Sep 2008 21:21:54 -0700 Subject: tcp: add tcp_can_forward_retransmit MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-) (limited to 'net') diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index cfae61b40c44..957c4e3d2176 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1992,6 +1992,33 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb) return err; } +static int tcp_can_forward_retransmit(struct sock *sk) +{ + const struct inet_connection_sock *icsk = inet_csk(sk); + struct tcp_sock *tp = tcp_sk(sk); + + /* Forward retransmissions are possible only during Recovery. */ + if (icsk->icsk_ca_state != TCP_CA_Recovery) + return 0; + + /* No forward retransmissions in Reno are possible. */ + if (tcp_is_reno(tp)) + return 0; + + /* Yeah, we have to make difficult choice between forward transmission + * and retransmission... Both ways have their merits... + * + * For now we do not retransmit anything, while we have some new + * segments to send. In the other cases, follow rule 3 for + * NextSeg() specified in RFC3517. + */ + + if (tcp_may_send_now(sk)) + return 0; + + return 1; +} + /* This gets called after a retransmit timeout, and the initially * retransmitted data is acknowledged. It tries to continue * resending the rest of the retransmit queue, until either @@ -2057,24 +2084,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) } /* OK, demanded retransmission is finished. */ - - /* Forward retransmissions are possible only during Recovery. */ - if (icsk->icsk_ca_state != TCP_CA_Recovery) - return; - - /* No forward retransmissions in Reno are possible. */ - if (tcp_is_reno(tp)) - return; - - /* Yeah, we have to make difficult choice between forward transmission - * and retransmission... Both ways have their merits... - * - * For now we do not retransmit anything, while we have some new - * segments to send. In the other cases, follow rule 3 for - * NextSeg() specified in RFC3517. - */ - - if (tcp_may_send_now(sk)) + if (!tcp_can_forward_retransmit(sk)) return; /* If nothing is SACKed, highest_sack in the loop won't be valid */ -- cgit v1.2.3