aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--include/net/sctp/structs.h2
-rw-r--r--net/sctp/input.c28
-rw-r--r--net/sctp/transport.c29
3 files changed, 36 insertions, 23 deletions
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 2f8f93da5dc2..9a5ccf03a59b 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -966,7 +966,7 @@ void sctp_transport_burst_limited(struct sctp_transport *);
void sctp_transport_burst_reset(struct sctp_transport *);
unsigned long sctp_transport_timeout(struct sctp_transport *);
void sctp_transport_reset(struct sctp_transport *t);
-void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
+bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
void sctp_transport_immediate_rtx(struct sctp_transport *);
void sctp_transport_dst_release(struct sctp_transport *t);
void sctp_transport_dst_confirm(struct sctp_transport *t);
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 621b5ca3fd1c..141c9c466ec1 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -399,20 +399,24 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
return;
}
- if (t->param_flags & SPP_PMTUD_ENABLE) {
- /* Update transports view of the MTU */
- sctp_transport_update_pmtu(t, pmtu);
-
- /* Update association pmtu. */
- sctp_assoc_sync_pmtu(asoc);
- }
+ if (!(t->param_flags & SPP_PMTUD_ENABLE))
+ /* We can't allow retransmitting in such case, as the
+ * retransmission would be sized just as before, and thus we
+ * would get another icmp, and retransmit again.
+ */
+ return;
- /* Retransmit with the new pmtu setting.
- * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
- * Needed will never be sent, but if a message was sent before
- * PMTU discovery was disabled that was larger than the PMTU, it
- * would not be fragmented, so it must be re-transmitted fragmented.
+ /* Update transports view of the MTU. Return if no update was needed.
+ * If an update wasn't needed/possible, it also doesn't make sense to
+ * try to retransmit now.
*/
+ if (!sctp_transport_update_pmtu(t, pmtu))
+ return;
+
+ /* Update association pmtu. */
+ sctp_assoc_sync_pmtu(asoc);
+
+ /* Retransmit with the new pmtu setting. */
sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
}
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 1e5a22430cf5..47f82bd794d9 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -248,28 +248,37 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
}
-void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
+bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
{
struct dst_entry *dst = sctp_transport_dst_check(t);
+ bool change = true;
if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
- pr_warn("%s: Reported pmtu %d too low, using default minimum of %d\n",
- __func__, pmtu, SCTP_DEFAULT_MINSEGMENT);
- /* Use default minimum segment size and disable
- * pmtu discovery on this transport.
- */
- t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
- } else {
- t->pathmtu = pmtu;
+ pr_warn_ratelimited("%s: Reported pmtu %d too low, using default minimum of %d\n",
+ __func__, pmtu, SCTP_DEFAULT_MINSEGMENT);
+ /* Use default minimum segment instead */
+ pmtu = SCTP_DEFAULT_MINSEGMENT;
}
+ pmtu = SCTP_TRUNC4(pmtu);
if (dst) {
dst->ops->update_pmtu(dst, t->asoc->base.sk, NULL, pmtu);
dst = sctp_transport_dst_check(t);
}
- if (!dst)
+ if (!dst) {
t->af_specific->get_dst(t, &t->saddr, &t->fl, t->asoc->base.sk);
+ dst = t->dst;
+ }
+
+ if (dst) {
+ /* Re-fetch, as under layers may have a higher minimum size */
+ pmtu = SCTP_TRUNC4(dst_mtu(dst));
+ change = t->pathmtu != pmtu;
+ }
+ t->pathmtu = pmtu;
+
+ return change;
}
/* Caches the dst entry and source address for a transport's destination