Date: Thu, 06 Sep 2007 09:11:42 -0400 From: Randall Stewart <rrs@cisco.com> To: sazzadur rahman <rahman.sazzadur@gmail.com> Cc: freebsd-net@freebsd.org, Peter Lei <peterlei@cisco.com> Subject: Re: A query regarding sctp_bindx api in SCTP Message-ID: <46DFFC8E.2030502@cisco.com> In-Reply-To: <82bdb5ec0709051817j16bfea69u74b9f4978c1f00fc@mail.gmail.com> References: <82bdb5ec0709051817j16bfea69u74b9f4978c1f00fc@mail.gmail.com>
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sazzadur rahman wrote:
> Hello,
> I am using sctp patch for freebsd6.1. For dynamic address configuration, I
> am calling sctp_bindx() API after successfull bind() and connect() API's.
> Although sctp_bindx() API successfully returns 0, the debug message shows:
>
> addr_mgmt_assoc: added to pending list...
> asconf_queue_add: appended asconf ADD_IP_ADDRESS...
>
> And I didn't see any ASCONF chunk sent to the peer in the tcpdump. Hence, I
> am confused why it should be in the pendling list instead of immediate send
> to peer?
Hmm.. I would like to see a packet trace of this as well..
A couple of thoughts.
a) The 6.x code is a bit out of date.. I need to update
and get a new patch out for you.. I know Peter did some
work on the ASCONF code recently.. so there may be some
fixes that have not been propagated to 6.x.. which could
be a problem (added Peter for that reason even though I
know he subscribes.. not sure how often he reads net).
b) Whenever an address gets added like this, then the address will
go into a pending point in the assoc. Since it can't be used
yet i.e. the ASCONF-ACK must be returned BEFORE the address
is part of the assoc. I am also not sure of the state of your
association at this point. I will try testing this... since it
is most likely in a front state, this may also be a problem.
The ASCONF cannot be sent until after we reach ESTABLISHED... not
sure we have tested this scenario.
c) Normally I would think you should do all the bindx BEFORE the
connect. When you do subset binding (which you are doing here
since you are NOT bound-all) then what you are saying is that
YOU the application wish to manage the addresses.. no automatic
ASCONF will be done for you. When you do the bindx() it is supposed
to kick off the ASCONF.. but again.. this may be an issue
since you are in a front state... I will test this scenario
with the latest 7.0 code and see if I can recreate it.
R
>
> In draft-ietf-tsvwg-addip-sctp-22.txt: page 20, A3, I have found that "If an
> ASCONF chunk is outstanding, then the ASCONF chunk should be queued for
> later transmission and no further action should be taken until the previous
> ASCONF is acknowledged or a timeout occurs." But as I am calling
> sctp_bindx() for the first time, there should not be any previous ASCONF
> existing.
>
> Does anyone have any idea what I am missing here?
> I would appriciate any help in this regard.
>
> Best Regards,
> Md. Sazzadur Rahman,
> Graduate Student,
> School of Computer Science,
> University of Oklahoma,
> Norman, USA
>
> ---------------------------code segment I have used---------------------
> //socket
> s = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP);
>
> //bind
> memset(&myAddr, 0, sizeof myAddr);
> myAddr.sin_family = AF_INET;
> myAddr.sin_port = htons(5060);
> myAddr.sin_addr.s_addr = inet_addr("129.15.78.125");
> if (bind(s, (struct sockaddr *)&myAddr, sizeof myAddr) < 0) {
> goto close;
> }
> //connect
> memset(&farAddr, 0, sizeof farAddr);
> farAddr.sin_family = AF_INET;
> farAddr.sin_port = htons(6060);
> farAddr.sin_addr.s_addr = inet_addr( "129.15.78.114" );
> int iRet = connect(s, (struct sockaddr *)&farAddr, sizeof farAddr);
>
> //sctp_bindx
> struct sockaddr_in my2ndAddr;
> memset(&my2ndAddr, 0, sizeof my2ndAddr);
> my2ndAddr.sin_len = sizeof my2ndAddr;
> my2ndAddr.sin_family = AF_INET;
> my2ndAddr.sin_port = htons(5060);
> my2ndAddr.sin_addr.s_addr = inet_addr("129.15.78.126");
>
> iRet = sctp_bindx(s,(struct
> sockaddr*)&my2ndAddr,1,SCTP_BINDX_ADD_ADDR);
>
> ------------------------------------------
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--
Randall Stewart
NSSTG - Cisco Systems Inc.
803-345-0369 <or> 803-317-4952 (cell)
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