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authorMatija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com>2014-02-20 14:13:04 +0100
committerDavid S. Miller <davem@davemloft.net>2014-02-20 13:24:56 -0500
commit7cce3b75682ff898c935c17d186983cbf3ed393e (patch)
tree2a2bd982c4b94eb0745031e2dc106451a42b05b9 /net/sctp
parentfb8ef788680d48523321e5f150b23700a1caf980 (diff)
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net: sctp: Potentially-Failed state should not be reached from unconfirmed state
In current implementation it is possible to reach PF state from unconfirmed. We can interpret sctp-failover-02 in a way that PF state is meant to be reached only from active state, in the end, this is when entering PF state makes sense. Here are few quotes from sctp-failover-02, but regardless of these, same understanding can be reached from whole section 5: Section 5.1, quickfailover guide: "The PF state is an intermediate state between Active and Failed states." "Each time the T3-rtx timer expires on an active or idle destination, the error counter of that destination address will be incremented. When the value in the error counter exceeds PFMR, the endpoint should mark the destination transport address as PF." There are several concrete reasons for such interpretation. For start, rfc4960 does not take into concern quickfailover algorithm. Therefore, quickfailover must comply to 4960. Point where this compliance can be argued is following behavior: When PF is entered, association overall error counter is incremented for each missed HB. This is contradictory to rfc4960, as address, while in unconfirmed state, is subjected to probing, and while it is probed, it should not increment association overall error counter. This has as a consequence that we might end up in situation in which we drop association due path failure on unconfirmed address, in case we have wrong configuration in a way: Association.Max.Retrans == Path.Max.Retrans. Another reason is that entering PF from unconfirmed will cause a loss of address confirmed event when address is once (if) confirmed. This is fine from failover guide point of view, but it is not consistent with behavior preceding failover implementation and recommendation from 4960: 5.4. Path Verification Whenever a path is confirmed, an indication MAY be given to the upper layer. Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/sm_sideeffect.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index bd859154000e..5d6883ff00c3 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -495,11 +495,12 @@ static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
}
/* If the transport error count is greater than the pf_retrans
- * threshold, and less than pathmaxrtx, then mark this transport
- * as Partially Failed, ee SCTP Quick Failover Draft, secon 5.1,
- * point 1
+ * threshold, and less than pathmaxrtx, and if the current state
+ * is not SCTP_UNCONFIRMED, then mark this transport as Partially
+ * Failed, see SCTP Quick Failover Draft, section 5.1
*/
if ((transport->state != SCTP_PF) &&
+ (transport->state != SCTP_UNCONFIRMED) &&
(asoc->pf_retrans < transport->pathmaxrxt) &&
(transport->error_count > asoc->pf_retrans)) {