From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH] net: sctp: bug-fixing: retran_path not set properly after transports recovering (v2) Date: Wed, 13 Nov 2013 17:13:17 -0500 Message-ID: <5283F97D.7000904@gmail.com> References: <1384379666-7541-1-git-send-email-changxiangzhong@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: nhorman@tuxdriver.com, davem@davemloft.net, linux-sctp@vger.kernel.org, netdev@vger.kernel.org To: Chang Xiangzhong Return-path: Received: from mail-gg0-f174.google.com ([209.85.161.174]:55565 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034Ab3KMWNU (ORCPT ); Wed, 13 Nov 2013 17:13:20 -0500 In-Reply-To: <1384379666-7541-1-git-send-email-changxiangzhong@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 11/13/2013 04:54 PM, Chang Xiangzhong wrote: > When a transport recovers due to the new coming sack, SCTP should > iterate all of its transport_list to locate the __two__ most recently used > transport and set to active_path and retran_path respectively. The exising > code does not find the two properly - In case of the following list: > > [most-recent] -> [2nd-most-recent] -> ... > > Both active_path and retran_path would be set to the 1st element. > > The bug happens when: > 1) multi-homing > 2) failure/partial_failure transport recovers > Both active_path and retran_path would be set to the same most-recent one, in > other words, retran_path would not take its role - an end user might not even > notice this issue. > > Signed-off-by: Chang Xiangzhong > --- > net/sctp/associola.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/net/sctp/associola.c b/net/sctp/associola.c > index ab67efc..a7fc856 100644 > --- a/net/sctp/associola.c > +++ b/net/sctp/associola.c > @@ -913,11 +913,12 @@ void sctp_assoc_control_transport(struct sctp_association *asoc, > if (!first || t->last_time_heard > first->last_time_heard) { > second = first; > first = t; > - } > - if (!second || t->last_time_heard > second->last_time_heard) > + } else if (!second || > + t->last_time_heard > second->last_time_heard) Align with !second. > second = t; > } > > + Spurious new line. -vlad > /* RFC 2960 6.4 Multi-Homed SCTP Endpoints > * > * By default, an endpoint should always transmit to the > @@ -935,6 +936,8 @@ void sctp_assoc_control_transport(struct sctp_association *asoc, > first = asoc->peer.primary_path; > } > > + if (!second) > + second = first; > /* If we failed to find a usable transport, just camp on the > * primary, even if it is inactive. > */ >