From patchwork Sat Sep 20 17:52:25 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 724 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 30579DDE00 for ; Sun, 21 Sep 2008 03:52:54 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751357AbYITRwp (ORCPT ); Sat, 20 Sep 2008 13:52:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751344AbYITRwn (ORCPT ); Sat, 20 Sep 2008 13:52:43 -0400 Received: from courier.cs.helsinki.fi ([128.214.9.1]:39329 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884AbYITRwi (ORCPT ); Sat, 20 Sep 2008 13:52:38 -0400 Received: from wrl-59.cs.helsinki.fi (wrl-59.cs.helsinki.fi [128.214.166.179]) (AUTH: PLAIN cs-relay, TLS: TLSv1/SSLv3,256bits,AES256-SHA) by mail.cs.helsinki.fi with esmtp; Sat, 20 Sep 2008 20:52:34 +0300 id 0005BED6.48D53862.00002CA5 Received: by wrl-59.cs.helsinki.fi (Postfix, from userid 50795) id 69B52A00A8; Sat, 20 Sep 2008 20:52:34 +0300 (EEST) From: "=?ISO-8859-1?Q?Ilpo_J=E4rvinen?=" To: David Miller Cc: netdev@vger.kernel.org, "=?utf-8?q?Ilpo=20J=E4rvinen?=" Subject: [PATCH net-next 07/15] tcp: add tcp_can_forward_retransmit Date: Sat, 20 Sep 2008 20:52:25 +0300 Message-Id: <1221933153-11874-8-git-send-email-ilpo.jarvinen@helsinki.fi> X-Mailer: git-send-email 1.5.4.2.156.ge3c5 In-Reply-To: <1221933153-11874-7-git-send-email-ilpo.jarvinen@helsinki.fi> References: <1221933153-11874-1-git-send-email-ilpo.jarvinen@helsinki.fi> <1221933153-11874-2-git-send-email-ilpo.jarvinen@helsinki.fi> <1221933153-11874-3-git-send-email-ilpo.jarvinen@helsinki.fi> <1221933153-11874-4-git-send-email-ilpo.jarvinen@helsinki.fi> <1221933153-11874-5-git-send-email-ilpo.jarvinen@helsinki.fi> <1221933153-11874-6-git-send-email-ilpo.jarvinen@helsinki.fi> <1221933153-11874-7-git-send-email-ilpo.jarvinen@helsinki.fi> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Signed-off-by: Ilpo Järvinen --- net/ipv4/tcp_output.c | 46 ++++++++++++++++++++++++++++------------------ 1 files changed, 28 insertions(+), 18 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index fbe10f4..2cec9b2 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1994,6 +1994,33 @@ 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 @@ -2059,24 +2086,7 @@ 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 */