SCTP_PEER_ADDR_CHANGE Notification over UNCONFIRMED path

Hi, Vlad && DEEPAK && Michael && David

From Michael && DEEPAK
"
lxr SCTP implementation, doesn't transit the path state to INACTIVE,
if it was never confirmed. this leads to SCTP_PEER_ADDRESS_CHANGE notification after each failed probe from this time.
Is there any specific reason to have same notification to SCTP User
with each probe in RTO time period ?
806 case SCTP_TRANSPORT_DOWN:
807 /* If the transport was never confirmed, do not transition it
808 * to inactive state. Also, release the cached route since
809 * there may be a better route next time.
810 */
811 if (transport->state != SCTP_UNCONFIRMED)

812 transport->state = SCTP_INACTIVE;

http://lxr.free-electrons.com/source/net/sctp/associola.c#L806

we checked RFC and here it is mentioned as Path Verification
Section(5.4) of RFC 4960 http://tools.ietf.org/html/rfc4960

In each RTO, a probe may be sent on an active UNCONFIRMED path in an attempt to move it to the CONFIRMED state. If during this probing the path becomes inactive, this rate is lowered to the normal HEARTBEAT rate. At the expiration of the RTO timer, the error counter of any path that was probed but not CONFIRMED is incremented by one and subjected to path failure detection, as defined in Section

8.2
. When probing UNCONFIRMED addresses, however, the association overall error counter is not incremented

Does this mean that in attempt to move a UNCONFIRMED path to CONFIRMED
State, the path can become INACTIVE, when transport error counter reaches to path_max_retrans counter ?
I would say that the path stays UNCONFIRMED.

I would also only expect a SCTP_PEER_ADDRESS_CHANGE notification when
a path state changes, not on every try.

"

I made a patch to disable sending SCTP_PEER_ADDRESS_CHANGE notification every try. Now the patch is in the attachment. Please check it.

Zhu Yanjun

From: Zhu Yanjun <[email protected]>
Date: Fri, 15 Aug 2014 16:32:51 +0800
Subject: [PATCH 1/1] sctp: not send SCTP_PEER_ADDR_CHANGE notifications with
failed probe

When a failed probe comes along UNCONFIRMED path, it is not necessary to send SCTP_PEER_ADDR_CHANGE notification.

---
 net/sctp/associola.c | 1 +
 1 file changed, 1 insertion(+)

index 9de23a2..2e23f6b 100644
@@ -813,6 +813,7 @@ void sctp_assoc_control_transport(struct sctp_association *asoc,
 		else {
 			dst_release(transport->dst);
 			transport->dst = NULL;
+			ulp_notify = false;
 		}
 
 		spc_state = SCTP_ADDR_UNREACHABLE;

1.9.1

Sorry. I used attachment to send patch. Maybe it is not convenient. Now I resend it again. Please ignore this mail.

Best Regards!
Zhu Yanjun