From: Wei Yongjun <yjwei@cn.fujitsu.com>
To: linux-sctp@vger.kernel.org
Subject: Re: Question regarding struct sctp_association
Date: Wed, 12 Jan 2011 01:00:28 +0000 [thread overview]
Message-ID: <4D2CFD2C.5010801@cn.fujitsu.com> (raw)
In-Reply-To: <4D2AF2C3.8010306@freyther.de>
> On 01/11/2011 10:12 AM, Wei Yongjun wrote:
>>> The sctp_packet has a pointer to sctp_transport. Does every sctp_transport
>>> hold a valid pointer to sctp_association? Does it hold a valid pointer if
>> assoc not always valid, when we response to an OOTB packet, the
>> assoc will be NULL.
> Thanks, I am sorry if the next question is totally obvious. I am obviously not
> too familiar with SCTP and the implementation here. For an OOTB packet we
> first check if we want to ignore it according to the RFC and then it will be
> placed in sctp_inq_push(&chunk->rcvr->inqueue, chunk) and here is where I am
> lost and the below is just guessing.
>
>
> --- a/net/sctp/output.c
> +++ b/net/sctp/output.c
> @@ -490,7 +490,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
> * HMAC field set to zero (as shown in Figure 6) followed by all
> * chunks that are placed after the AUTH chunk in the SCTP packet.
> */
> - if (auth)
> + if (auth && asoc)
> sctp_auth_calculate_hmac(asoc, nskb,
> (struct sctp_auth_chunk *)auth,
> GFP_ATOMIC);
>
> Can an OOTB packet force us to calculate the hmac here?
if we don't have an association, we can't do authentication, so if auth
then asoc is not NULL.
>
>
> @@ -563,7 +563,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
> unsigned long timeout;
>
> /* Restart the AUTOCLOSE timer when sending data. */
> - if (sctp_state(asoc, ESTABLISHED) && asoc->autoclose) {
> + if (asoc && sctp_state(asoc, ESTABLISHED) && asoc->autoclose) {
> timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
> timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
>
>
> Can an OOTB packet contain data chunks that would make us go through this path?
AUTOCLOSE timer is only start when we have association, so this will
not happen.
>
>
> --
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>
next prev parent reply other threads:[~2011-01-12 1:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-10 11:51 Question regarding struct sctp_association Holger Hans Peter Freyther
2011-01-11 9:12 ` Wei Yongjun
2011-01-11 10:29 ` Holger Hans Peter Freyther
2011-01-12 1:00 ` Wei Yongjun [this message]
2011-01-12 14:35 ` Holger Hans Peter Freyther
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