Re: Fwd: Question on SCTP ABORT chunk is generated when the association_max_retrans is reached

From: Daniel Borkmann
Date: Fri Jan 23 2015 - 06:50:41 EST


Hi,

On 01/23/2015 11:25 AM, Sun Paul wrote:
...
I would like to check the behave in LKSCTP.

we are running DIAMETER message over SCTP, and we have set the
parameter "net.sctp.association_max_retrans = 4" in the LinuxOS.

We noticed that when remote peer have retry to send the same request
for 4 times, the LKSCTP will initiate an ABORT chunk with reason
"association exceeded its max_retrans count".

We would like to know whether this is the correct behavior? is there
any other option that we can alter in order to avoid the ABORT chunk
being sent?

I don't recall the RFC saying to send an ABORT, but let me double
check in the mean time.

Hmm, untested, but could you try something like that?

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index fef2acd..5ce198d 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -584,7 +584,8 @@ static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(event));

- if (asoc->overall_error_count >= asoc->max_retrans) {
+ if (asoc->overall_error_count >= asoc->max_retrans &&
+ error != SCTP_ERROR_NO_ERROR) {
abort = sctp_make_violation_max_retrans(asoc, chunk);
if (abort)
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
--
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