Thread (24 messages) flat view 24 messages, 5 authors, 2012-07-23

Re: [PATCH v3] sctp: Implement quick failover draft from tsvwg

From: Flavio Leitner <hidden>
Date: 2012-07-20 16:52:06
Also in: linux-sctp

On Thu, 19 Jul 2012 12:51:44 -0400
Neil Horman [off-list ref] wrote:
[...]
 
+pf_retrans - INTEGER
+	The number of retransmissions that will be attempted on a given path
+	before traffic is redirected to an alternate transport (should one
+	exist).  Note this is distinct from path_max_retrans, as a path that
+	passes the pf_retrans threshold can still be used.  Its only
+	deprioritized when a transmission path is selected by the stack.  This
+	setting is primarily used to enable fast failover mechanisms without
+	having to reduce path_max_retrans to a very low value.  See:
+	http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt
+	for details.  Note also that a value of pf_retrans > path_max_retrans
+	disables this feature
+
+	Default: 0
+
 rto_initial - INTEGER
[...]
quoted hunk ↗ jump to hunk
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index e4652fe..f70726c 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -160,6 +160,7 @@ extern struct sctp_globals {
 	int max_retrans_association;
 	int max_retrans_path;
 	int max_retrans_init;
+	int pf_retrans;
[...]
quoted hunk ↗ jump to hunk
 
+	/* This is the partially failed retrans value for the transport
+	 * and will be initialized from the assocs value.  This can be changed
+	 * using the SCTP_PEER_ADDR_THLDS socket option
+	 */
+	int pf_retrans;
 	/* PMTU	      : The current known path MTU.  */
 	__u32 pathmtu;
 
@@ -1660,6 +1667,8 @@ struct sctp_association {
 	 */
 	int max_retrans;
 
+	int pf_retrans;
+

You've documented in one place, but not in the others.  I suggest to include
references like this
       /* See the description in struct sctp_transport */
at the two missing places.

Nice feature,
fbl
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