From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chang Subject: Re: [PATCH] net: sctp: recover a tranport when an ack comes Date: Fri, 15 Nov 2013 23:04:28 +0100 Message-ID: <52869A6C.8060900@gmail.com> References: <1384461624-17636-1-git-send-email-changxiangzhong@gmail.com> <5285884F.8030907@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, linux-sctp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, dreibh@simula.no, ernstgr@simula.no To: Vlad Yasevich , nhorman@tuxdriver.com Return-path: Received: from mail-la0-f42.google.com ([209.85.215.42]:52011 "EHLO mail-la0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752797Ab3KOWEa (ORCPT ); Fri, 15 Nov 2013 17:04:30 -0500 In-Reply-To: <5285884F.8030907@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 11/15/2013 03:34 AM, Vlad Yasevich wrote: > I don't think this is right. The spec states: > 8. ACKs for retransmissions do not transition a PF destination back > to Active state, since a sender cannot disambiguate whether the > ack was for the original transmission or the retransmission(s). > Could you please reconsider my proposal? In the rule 8, it clearly specifies ACKs for *retransmission* do not transition ... But those chunks were not retransmitted! Every transport maintains its own [transport->transmitted] queue, when retransmit happens (no matter time_out or fast_retransmit). The chunk would be removed from the queue and moved to the sctp_outq->retransmit. static void sctp_check_transmitted(...) { ... if (transport) { /*<=======This proves that its not the outq->retransmit (the retransmitted queue)*/ if (bytes_acked) { ... if((transport->state in [INACTIVE, UNCONFIRMED, PF]...) sctp_assoc_control_transport(..., SCTP_TRANSPORT_UP). In addition, if its not appropriate to transition PF->ACTIVE, why is it appropriate to transition INACTIVE->ACTIVE (the original implementation). > > Now, the proper way to this would would be modify > sctp_assoc_control_transport() to transition the transport state to > ACTIVE if it was PF transport that was chosen to send data. > > -vlad > >> --- >> net/sctp/outqueue.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c >> index 94df758..2557fa5 100644 >> --- a/net/sctp/outqueue.c >> +++ b/net/sctp/outqueue.c >> @@ -1517,6 +1517,7 @@ static void sctp_check_transmitted(struct >> sctp_outq *q, >> * active if it is not so marked. >> */ >> if ((transport->state == SCTP_INACTIVE || >> + transport->state == SCTP_PF || >> transport->state == SCTP_UNCONFIRMED) && >> sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { >> sctp_assoc_control_transport( >> >