subject:"\[Lksctp\-developers\] \[PATCH\] SCTP\: drop SACK if ctsn is not less than the next tsn of assoc"

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

2007-08-01 Thread Michael Tuexen


Hi Wei,

see my comments in-line.

Best regards
Michael

On Aug 1, 2007, at 3:06 AM, Wei Yongjun wrote:




On Tue, 2007-07-31 at 07:37 -0400, Neil Horman wrote:


On Tue, Jul 31, 2007 at 12:44:27PM +0800, Wei Yongjun wrote:

If SCTP data sender received a SACK which contains Cumulative  
TSN Ack is
not less than the Cumulative TSN Ack Point, and if this  
Cumulative TSN
Ack is not used by the data sender, SCTP data sender still  
accept this
SACK , and next SACK which send correctly to DATA sender be  
dropped,

because it is less than the new Cumulative TSN Ack Point.
After received this SACK, data will be retrans again and again  
even if

correct SACK is received.
So I think this SACK must be dropped to let data transmit   
correctly.


Following is the tcpdump of my test. And patch in this mail can  
avoid

this problem.

02:19:38.233278 sctp (1) [INIT] [init tag: 1250461886] [rwnd:  
54784] [OS: 10] [MIS: 65535] [init TSN: 217114040]
02:19:39.782160 sctp (1) [INIT ACK] [init tag: 1] [rwnd: 54784]  
[OS: 100] [MIS: 65535] [init TSN: 100]

02:19:39.798583 sctp (1) [COOKIE ECHO]
02:19:40.082125 sctp (1) [COOKIE ACK]
02:19:40.097859 sctp (1) [DATA] (B)(E) [TSN: 217114040] [SID: 0]  
[SSEQ 0] [PPID 0xf192090b]
02:19:40.100162 sctp (1) [DATA] (B)(E) [TSN: 217114041] [SID: 0]  
[SSEQ 1] [PPID 0x3e467007]
02:19:40.100779 sctp (1) [DATA] (B)(E) [TSN: 217114042] [SID: 0]  
[SSEQ 2] [PPID 0x11b12a0a]
02:19:40.101200 sctp (1) [DATA] (B)(E) [TSN: 217114043] [SID: 0]  
[SSEQ 3] [PPID 0x30e7d979]
02:19:40.561147 sctp (1) [SACK] [cum ack 217114040] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:40.568498 sctp (1) [DATA] (B)(E) [TSN: 217114044] [SID: 0]  
[SSEQ 4] [PPID 0x251ff86f]
02:19:40.569308 sctp (1) [DATA] (B)(E) [TSN: 217114045] [SID: 0]  
[SSEQ 5] [PPID 0xe5d5da5d]
02:19:40.700584 sctp (1) [SACK] [cum ack 290855864] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:40.701562 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0]  
[SSEQ 6] [PPID 0x87d8b423]
02:19:40.701567 sctp (1) [DATA] (B)(E) [TSN: 217114047] [SID: 0]  
[SSEQ 7] [PPID 0xca47e645]
02:19:40.701569 sctp (1) [DATA] (B)(E) [TSN: 217114048] [SID: 0]  
[SSEQ 8] [PPID 0x6c0ea150]
02:19:40.701576 sctp (1) [DATA] (B)(E) [TSN: 217114049] [SID: 0]  
[SSEQ 9] [PPID 0x9cc1994f]
02:19:40.701585 sctp (1) [DATA] (B)(E) [TSN: 217114050] [SID: 0]  
[SSEQ 10] [PPID 0xb1df4129]
02:19:41.098201 sctp (1) [SACK] [cum ack 217114041] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:41.283257 sctp (1) [SACK] [cum ack 217114042] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:41.457217 sctp (1) [SACK] [cum ack 217114043] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:41.691528 sctp (1) [SACK] [cum ack 217114044] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:41.849636 sctp (1) [SACK] [cum ack 217114045] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:41.975473 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0]  
[SSEQ 6] [PPID 0x87d8b423]
02:19:42.021229 sctp (1) [SACK] [cum ack 217114046] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:42.196495 sctp (1) [SACK] [cum ack 217114047] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:42.424319 sctp (1) [SACK] [cum ack 217114048] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:42.586924 sctp (1) [SACK] [cum ack 217114049] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:42.744810 sctp (1) [SACK] [cum ack 217114050] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:42.965536 sctp (1) [SACK] [cum ack 217114046] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:43.106385 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0]  
[SSEQ 6] [PPID 0x87d8b423]
02:19:43.218969 sctp (1) [SACK] [cum ack 217114046] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:45.374101 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0]  
[SSEQ 6] [PPID 0x87d8b423]
02:19:45.489258 sctp (1) [SACK] [cum ack 217114046] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:49.830116 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0]  
[SSEQ 6] [PPID 0x87d8b423]
02:19:49.984577 sctp (1) [SACK] [cum ack 217114046] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]
02:19:58.760300 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0]  
[SSEQ 6] [PPID 0x87d8b423]
02:19:58.931690 sctp (1) [SACK] [cum ack 217114046] [a_rwnd  
54784] [#gap acks 0] [#dup tsns 0]



Signed-off-by: Wei Yongjun [EMAIL PROTECTED]

--- net/sctp/sm_statefuns.c.orig	2007-07-29 18:11:01.0  
-0400

+++ net/sctp/sm_statefuns.c 2007-07-29 18:14:49.0 -0400
@@ -2880,6 +2880,15 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(
return SCTP_DISPOSITION_DISCARD;
}

+   /* If Cumulative TSN Ack is not less than the Cumulative TSN
+* Ack which will be send in the next data, drop the SACK.
+*/
+   if (!TSN_lt(ctsn, asoc-next_tsn)) {
+   SCTP_DEBUG_PRINTK(ctsn %x\n, ctsn);
+   SCTP_DEBUG_PRINTK(next_tsn %x\n, asoc-next_tsn);
+   return SCTP_DISPOSITION_DISCARD;
+   }
+
/* Return this

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

2007-08-01 Thread Neil Horman

On Wed, Aug 01, 2007 at 11:01:21AM +0200, Michael Tuexen wrote:
 Hi Wei,
 
 see my comments in-line.
 
 Best regards
 Michael
 
snip 
 (*1) At this point ctsn_ack_point=0,next_tsn=2, ctsn=1, SACK is  
 accept.
 After accept SACK, ctsn_ack_point=1.
 (*2) At this point ctsn_ack_point=1,next_tsn=6, ctsn=5,TSN_lt(ctsn,
 ctsn_ack_point) is ture, so accept SACK, and then ctsn_ack_point=5
 (*3) At this point SACK is a dup SACK, ctsn_ack_point=5,next_tsn=6,
 ctsn=1000,TSN_lt(ctsn, ctsn_ack_point) is ture, so accept SACK, and  
 then
 ctsn_ack_point=1000
 I would not consider it a duplicate SACK. RFC 4460, section 2.37.2 says
 that an implementation SHOULD abort the association when receiving a
 SACK acknowledging unsent data. So I would suggest to send an ABORT  
 chunk.

+1.  I didn't notice the ctsn value before.  We can't safely accept that a peer
pre-acks data we haven't sent.  Too many security holes.  

Neil



-- 
/***
 *Neil Horman
 *Software Engineer
 *Red Hat, Inc.
 [EMAIL PROTECTED]
 *gpg keyid: 1024D / 0x92A74FA1
 *http://pgp.mit.edu
 ***/
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Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

2007-08-01 Thread Vlad Yasevich

This is a little better.

One suggestion.  The new function you create is almost exactly like
sctp_sf_violation_chunklen() with the exception of the error string.
Can you extract the common parts into a single function so that
we don't have duplication of code.

Thanks
-vlad

Wei Yongjun wrote:
   
 This is an interesting case, but I am not sure that simply discarding
 the SACK is the right thing.

 The peer in this case is violating the protocol whereby he is trying to
 advance the cumulative tsn ack to a point beyond the max tsn currently
 sent. I would vote for terminating the association in this case since
 either the peer is a mis-behaved implementation, or the association is
 under attack.
 I have modify the patch to abort the association with protocol violation 
 error cause, and new patch is come on. May be this patch is correct.^_^
 
 Signed-off-by: Wei Yongjun [EMAIL PROTECTED]
 
 --- net/sctp/sm_statefuns.c.orig  2007-07-29 18:11:01.0 -0400
 +++ net/sctp/sm_statefuns.c   2007-07-31 00:29:16.0 -0400
 @@ -104,6 +104,13 @@ static sctp_disposition_t sctp_sf_violat
void *arg,
sctp_cmd_seq_t *commands);
  
 +static sctp_disposition_t sctp_sf_violation_ctsn(
 +  const struct sctp_endpoint *ep,
 +  const struct sctp_association *asoc,
 +  const sctp_subtype_t type,
 +  void *arg,
 +  sctp_cmd_seq_t *commands);
 +
  /* Small helper function that checks if the chunk length
   * is of the appropriate length.  The 'required_length' argument
   * is set to be the size of a specific chunk we are testing.
 @@ -2880,6 +2887,13 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(
   return SCTP_DISPOSITION_DISCARD;
   }
  
 + /* If Cumulative TSN Ack beyond the max tsn currently
 +  * send, terminating the association and respond to the 
 +  * sender with an ABORT.
 +  */
 + if (!TSN_lt(ctsn, asoc-next_tsn))
 + return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
 +
   /* Return this SACK for further processing.  */
   sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));
  
 @@ -3756,6 +3770,68 @@ nomem:
   return SCTP_DISPOSITION_NOMEM;
  }
  
 +/*
 + * Handle a protocol violation when the peer trying to advance the 
 + * cumulative tsn ack to a point beyond the max tsn currently sent.
 + *
 + * We inform the other end by sending an ABORT with a Protocol Violation
 + * error code.
 + *
 + * Section: Not specified
 + * Verification Tag:  Nothing to do
 + * Inputs
 + * (endpoint, asoc, chunk)
 + *
 + * Outputs
 + * (reply_msg, msg_up, counters)
 + *
 + * Generate an  ABORT chunk and terminate the association.
 + */
 +static sctp_disposition_t sctp_sf_violation_ctsn(
 +  const struct sctp_endpoint *ep,
 +  const struct sctp_association *asoc,
 +  const sctp_subtype_t type,
 +  void *arg,
 +  sctp_cmd_seq_t *commands)
 +{
 + struct sctp_chunk *chunk =  arg;
 + struct sctp_chunk *abort = NULL;
 + char err_str[] = The cumulative tsn ack beyond the max tsn currently 
 sent:;
 +
 + /* Make the abort chunk. */
 + abort = sctp_make_abort_violation(asoc, chunk, err_str,
 +   sizeof(err_str));
 + if (!abort)
 + goto nomem;
 +
 + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
 +
 + if (asoc-state = SCTP_STATE_COOKIE_ECHOED) {
 + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
 + sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
 + SCTP_ERROR(ECONNREFUSED));
 + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
 + SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
 + } else {
 + sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
 + SCTP_ERROR(ECONNABORTED));
 + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
 + SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
 + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
 + }
 +
 + sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
 +
 + SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
 +
 + return SCTP_DISPOSITION_ABORT;
 +
 +nomem:
 + return SCTP_DISPOSITION_NOMEM;
 +}
 +
  /***
   * These are the state functions for handling primitive (Section 10) events.
   ***/
 
 
 

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Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

2007-07-31 Thread Neil Horman

On Tue, Jul 31, 2007 at 12:44:27PM +0800, Wei Yongjun wrote:
 If SCTP data sender received a SACK which contains Cumulative TSN Ack is 
 not less than the Cumulative TSN Ack Point, and if this Cumulative TSN 
 Ack is not used by the data sender, SCTP data sender still accept this 
 SACK , and next SACK which send correctly to DATA sender be dropped, 
 because it is less than the new Cumulative TSN Ack Point.
 After received this SACK, data will be retrans again and again even if 
 correct SACK is received.
 So I think this SACK must be dropped to let data transmit  correctly.
 
 Following is the tcpdump of my test. And patch in this mail can avoid 
 this problem.
 
 02:19:38.233278 sctp (1) [INIT] [init tag: 1250461886] [rwnd: 54784] [OS: 10] 
 [MIS: 65535] [init TSN: 217114040] 
 02:19:39.782160 sctp (1) [INIT ACK] [init tag: 1] [rwnd: 54784] [OS: 100] 
 [MIS: 65535] [init TSN: 100] 
 02:19:39.798583 sctp (1) [COOKIE ECHO] 
 02:19:40.082125 sctp (1) [COOKIE ACK] 
 02:19:40.097859 sctp (1) [DATA] (B)(E) [TSN: 217114040] [SID: 0] [SSEQ 0] 
 [PPID 0xf192090b] 
 02:19:40.100162 sctp (1) [DATA] (B)(E) [TSN: 217114041] [SID: 0] [SSEQ 1] 
 [PPID 0x3e467007] 
 02:19:40.100779 sctp (1) [DATA] (B)(E) [TSN: 217114042] [SID: 0] [SSEQ 2] 
 [PPID 0x11b12a0a] 
 02:19:40.101200 sctp (1) [DATA] (B)(E) [TSN: 217114043] [SID: 0] [SSEQ 3] 
 [PPID 0x30e7d979] 
 02:19:40.561147 sctp (1) [SACK] [cum ack 217114040] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:40.568498 sctp (1) [DATA] (B)(E) [TSN: 217114044] [SID: 0] [SSEQ 4] 
 [PPID 0x251ff86f] 
 02:19:40.569308 sctp (1) [DATA] (B)(E) [TSN: 217114045] [SID: 0] [SSEQ 5] 
 [PPID 0xe5d5da5d] 
 02:19:40.700584 sctp (1) [SACK] [cum ack 290855864] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:40.701562 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:40.701567 sctp (1) [DATA] (B)(E) [TSN: 217114047] [SID: 0] [SSEQ 7] 
 [PPID 0xca47e645] 
 02:19:40.701569 sctp (1) [DATA] (B)(E) [TSN: 217114048] [SID: 0] [SSEQ 8] 
 [PPID 0x6c0ea150] 
 02:19:40.701576 sctp (1) [DATA] (B)(E) [TSN: 217114049] [SID: 0] [SSEQ 9] 
 [PPID 0x9cc1994f] 
 02:19:40.701585 sctp (1) [DATA] (B)(E) [TSN: 217114050] [SID: 0] [SSEQ 10] 
 [PPID 0xb1df4129] 
 02:19:41.098201 sctp (1) [SACK] [cum ack 217114041] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:41.283257 sctp (1) [SACK] [cum ack 217114042] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:41.457217 sctp (1) [SACK] [cum ack 217114043] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:41.691528 sctp (1) [SACK] [cum ack 217114044] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:41.849636 sctp (1) [SACK] [cum ack 217114045] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:41.975473 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:42.021229 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:42.196495 sctp (1) [SACK] [cum ack 217114047] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:42.424319 sctp (1) [SACK] [cum ack 217114048] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:42.586924 sctp (1) [SACK] [cum ack 217114049] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:42.744810 sctp (1) [SACK] [cum ack 217114050] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:42.965536 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:43.106385 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:43.218969 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:45.374101 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:45.489258 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:49.830116 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:49.984577 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 02:19:58.760300 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:58.931690 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap acks 
 0] [#dup tsns 0] 
 
 
 Signed-off-by: Wei Yongjun [EMAIL PROTECTED]
 
 --- net/sctp/sm_statefuns.c.orig  2007-07-29 18:11:01.0 -0400
 +++ net/sctp/sm_statefuns.c   2007-07-29 18:14:49.0 -0400
 @@ -2880,6 +2880,15 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(
   return SCTP_DISPOSITION_DISCARD;
   }
  
 + /* If Cumulative TSN Ack is not less than the Cumulative TSN
 +  * Ack which will be send in the next data, drop the SACK.
 +  */
 + if (!TSN_lt(ctsn, asoc-next_tsn)) {
 + SCTP_DEBUG_PRINTK(ctsn %x\n, ctsn);
 + SCTP_DEBUG_PRINTK(next_tsn %x\n, asoc-next_tsn);
 + return SCTP_DISPOSITION_DISCARD;
 + }
 +
   /* Return this SACK for further processing.  */
   sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

2007-07-31 Thread Sridhar Samudrala

On Tue, 2007-07-31 at 07:37 -0400, Neil Horman wrote:
 On Tue, Jul 31, 2007 at 12:44:27PM +0800, Wei Yongjun wrote:
  If SCTP data sender received a SACK which contains Cumulative TSN Ack is 
  not less than the Cumulative TSN Ack Point, and if this Cumulative TSN 
  Ack is not used by the data sender, SCTP data sender still accept this 
  SACK , and next SACK which send correctly to DATA sender be dropped, 
  because it is less than the new Cumulative TSN Ack Point.
  After received this SACK, data will be retrans again and again even if 
  correct SACK is received.
  So I think this SACK must be dropped to let data transmit  correctly.
  
  Following is the tcpdump of my test. And patch in this mail can avoid 
  this problem.
  
  02:19:38.233278 sctp (1) [INIT] [init tag: 1250461886] [rwnd: 54784] [OS: 
  10] [MIS: 65535] [init TSN: 217114040] 
  02:19:39.782160 sctp (1) [INIT ACK] [init tag: 1] [rwnd: 54784] [OS: 100] 
  [MIS: 65535] [init TSN: 100] 
  02:19:39.798583 sctp (1) [COOKIE ECHO] 
  02:19:40.082125 sctp (1) [COOKIE ACK] 
  02:19:40.097859 sctp (1) [DATA] (B)(E) [TSN: 217114040] [SID: 0] [SSEQ 0] 
  [PPID 0xf192090b] 
  02:19:40.100162 sctp (1) [DATA] (B)(E) [TSN: 217114041] [SID: 0] [SSEQ 1] 
  [PPID 0x3e467007] 
  02:19:40.100779 sctp (1) [DATA] (B)(E) [TSN: 217114042] [SID: 0] [SSEQ 2] 
  [PPID 0x11b12a0a] 
  02:19:40.101200 sctp (1) [DATA] (B)(E) [TSN: 217114043] [SID: 0] [SSEQ 3] 
  [PPID 0x30e7d979] 
  02:19:40.561147 sctp (1) [SACK] [cum ack 217114040] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:40.568498 sctp (1) [DATA] (B)(E) [TSN: 217114044] [SID: 0] [SSEQ 4] 
  [PPID 0x251ff86f] 
  02:19:40.569308 sctp (1) [DATA] (B)(E) [TSN: 217114045] [SID: 0] [SSEQ 5] 
  [PPID 0xe5d5da5d] 
  02:19:40.700584 sctp (1) [SACK] [cum ack 290855864] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:40.701562 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
  [PPID 0x87d8b423] 
  02:19:40.701567 sctp (1) [DATA] (B)(E) [TSN: 217114047] [SID: 0] [SSEQ 7] 
  [PPID 0xca47e645] 
  02:19:40.701569 sctp (1) [DATA] (B)(E) [TSN: 217114048] [SID: 0] [SSEQ 8] 
  [PPID 0x6c0ea150] 
  02:19:40.701576 sctp (1) [DATA] (B)(E) [TSN: 217114049] [SID: 0] [SSEQ 9] 
  [PPID 0x9cc1994f] 
  02:19:40.701585 sctp (1) [DATA] (B)(E) [TSN: 217114050] [SID: 0] [SSEQ 10] 
  [PPID 0xb1df4129] 
  02:19:41.098201 sctp (1) [SACK] [cum ack 217114041] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:41.283257 sctp (1) [SACK] [cum ack 217114042] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:41.457217 sctp (1) [SACK] [cum ack 217114043] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:41.691528 sctp (1) [SACK] [cum ack 217114044] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:41.849636 sctp (1) [SACK] [cum ack 217114045] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:41.975473 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
  [PPID 0x87d8b423] 
  02:19:42.021229 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:42.196495 sctp (1) [SACK] [cum ack 217114047] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:42.424319 sctp (1) [SACK] [cum ack 217114048] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:42.586924 sctp (1) [SACK] [cum ack 217114049] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:42.744810 sctp (1) [SACK] [cum ack 217114050] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:42.965536 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:43.106385 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
  [PPID 0x87d8b423] 
  02:19:43.218969 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:45.374101 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
  [PPID 0x87d8b423] 
  02:19:45.489258 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:49.830116 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
  [PPID 0x87d8b423] 
  02:19:49.984577 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  02:19:58.760300 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
  [PPID 0x87d8b423] 
  02:19:58.931690 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
  acks 0] [#dup tsns 0] 
  
  
  Signed-off-by: Wei Yongjun [EMAIL PROTECTED]
  
  --- net/sctp/sm_statefuns.c.orig2007-07-29 18:11:01.0 -0400
  +++ net/sctp/sm_statefuns.c 2007-07-29 18:14:49.0 -0400
  @@ -2880,6 +2880,15 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(
  return SCTP_DISPOSITION_DISCARD;
  }
   
  +   /* If Cumulative TSN Ack is not less than the Cumulative TSN
  +* Ack which will be send in the next data, drop the SACK.
  +*/
  +   if (!TSN_lt(ctsn, asoc-next_tsn)) {
  +   SCTP_DEBUG_PRINTK(ctsn %x\n, ctsn);
  +   SCTP_DEBUG_PRINTK(next_tsn %x\n, asoc-next_tsn);
  +   return

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

2007-07-31 Thread Vlad Yasevich

Sorry, coming in late due to list issues...

Wei Yongjun wrote:
 On Tue, 2007-07-31 at 07:37 -0400, Neil Horman wrote:
   
 On Tue, Jul 31, 2007 at 12:44:27PM +0800, Wei Yongjun wrote:
 
 If SCTP data sender received a SACK which contains Cumulative TSN Ack is 
 not less than the Cumulative TSN Ack Point, and if this Cumulative TSN 
 Ack is not used by the data sender, SCTP data sender still accept this 
 SACK , and next SACK which send correctly to DATA sender be dropped, 
 because it is less than the new Cumulative TSN Ack Point.
 After received this SACK, data will be retrans again and again even if 
 correct SACK is received.
 So I think this SACK must be dropped to let data transmit  correctly.

 Following is the tcpdump of my test. And patch in this mail can avoid 
 this problem.

 02:19:38.233278 sctp (1) [INIT] [init tag: 1250461886] [rwnd: 54784] [OS: 
 10] [MIS: 65535] [init TSN: 217114040] 
 02:19:39.782160 sctp (1) [INIT ACK] [init tag: 1] [rwnd: 54784] [OS: 100] 
 [MIS: 65535] [init TSN: 100] 
 02:19:39.798583 sctp (1) [COOKIE ECHO] 
 02:19:40.082125 sctp (1) [COOKIE ACK] 
 02:19:40.097859 sctp (1) [DATA] (B)(E) [TSN: 217114040] [SID: 0] [SSEQ 0] 
 [PPID 0xf192090b] 
 02:19:40.100162 sctp (1) [DATA] (B)(E) [TSN: 217114041] [SID: 0] [SSEQ 1] 
 [PPID 0x3e467007] 
 02:19:40.100779 sctp (1) [DATA] (B)(E) [TSN: 217114042] [SID: 0] [SSEQ 2] 
 [PPID 0x11b12a0a] 
 02:19:40.101200 sctp (1) [DATA] (B)(E) [TSN: 217114043] [SID: 0] [SSEQ 3] 
 [PPID 0x30e7d979] 
 02:19:40.561147 sctp (1) [SACK] [cum ack 217114040] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:40.568498 sctp (1) [DATA] (B)(E) [TSN: 217114044] [SID: 0] [SSEQ 4] 
 [PPID 0x251ff86f] 
 02:19:40.569308 sctp (1) [DATA] (B)(E) [TSN: 217114045] [SID: 0] [SSEQ 5] 
 [PPID 0xe5d5da5d] 
 02:19:40.700584 sctp (1) [SACK] [cum ack 290855864] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:40.701562 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:40.701567 sctp (1) [DATA] (B)(E) [TSN: 217114047] [SID: 0] [SSEQ 7] 
 [PPID 0xca47e645] 
 02:19:40.701569 sctp (1) [DATA] (B)(E) [TSN: 217114048] [SID: 0] [SSEQ 8] 
 [PPID 0x6c0ea150] 
 02:19:40.701576 sctp (1) [DATA] (B)(E) [TSN: 217114049] [SID: 0] [SSEQ 9] 
 [PPID 0x9cc1994f] 
 02:19:40.701585 sctp (1) [DATA] (B)(E) [TSN: 217114050] [SID: 0] [SSEQ 10] 
 [PPID 0xb1df4129] 
 02:19:41.098201 sctp (1) [SACK] [cum ack 217114041] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:41.283257 sctp (1) [SACK] [cum ack 217114042] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:41.457217 sctp (1) [SACK] [cum ack 217114043] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:41.691528 sctp (1) [SACK] [cum ack 217114044] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:41.849636 sctp (1) [SACK] [cum ack 217114045] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:41.975473 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:42.021229 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:42.196495 sctp (1) [SACK] [cum ack 217114047] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:42.424319 sctp (1) [SACK] [cum ack 217114048] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:42.586924 sctp (1) [SACK] [cum ack 217114049] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:42.744810 sctp (1) [SACK] [cum ack 217114050] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:42.965536 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:43.106385 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:43.218969 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:45.374101 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:45.489258 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:49.830116 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:49.984577 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 
 02:19:58.760300 sctp (1) [DATA] (B)(E) [TSN: 217114046] [SID: 0] [SSEQ 6] 
 [PPID 0x87d8b423] 
 02:19:58.931690 sctp (1) [SACK] [cum ack 217114046] [a_rwnd 54784] [#gap 
 acks 0] [#dup tsns 0] 


 Signed-off-by: Wei Yongjun [EMAIL PROTECTED]

 --- net/sctp/sm_statefuns.c.orig   2007-07-29 18:11:01.0 -0400
 +++ net/sctp/sm_statefuns.c2007-07-29 18:14:49.0 -0400
 @@ -2880,6 +2880,15 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(
return SCTP_DISPOSITION_DISCARD;
}
  
 +  /* If Cumulative TSN Ack is not less than the Cumulative TSN
 +   * Ack which will be send in the next data, drop the SACK.
 +   */
 +  if (!TSN_lt(ctsn, asoc-next_tsn)) {
 +  SCTP_DEBUG_PRINTK(ctsn %x\n, ctsn);
 +  SCTP_DEBUG_PRINTK(next_tsn %x\n, asoc-next_tsn);
 +  return SCTP_DISPOSITION_DISCARD;
 +  }
 +
/* Return this

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc

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