@@ -1023,6 +1023,7 @@ 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);
+void sctp_transport_pl_send(struct sctp_transport *t);
/* This is the structure we use to queue packets as they come into
@@ -1109,6 +1109,8 @@ enum sctp_disposition sctp_sf_send_probe(struct net *net,
if (!sctp_transport_pl_enabled(transport))
return SCTP_DISPOSITION_CONSUME;
+ sctp_transport_pl_send(transport);
+
reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
if (!reply)
return SCTP_DISPOSITION_NOMEM;
@@ -261,6 +261,50 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
}
+void sctp_transport_pl_send(struct sctp_transport *t)
+{
+ pr_debug("%s: PLPMTUD: transport: %p, state: %d, pmtu: %d, size: %d, high: %d\n",
+ __func__, t, t->pl.state, t->pl.pmtu, t->pl.probe_size, t->pl.probe_high);
+
+ if (t->pl.probe_count < SCTP_MAX_PROBES) {
+ t->pl.probe_count++;
+ return;
+ }
+
+ if (t->pl.state == SCTP_PL_BASE) {
+ if (t->pl.probe_size == SCTP_BASE_PLPMTU) { /* BASE_PLPMTU Confirmation Failed */
+ t->pl.state = SCTP_PL_ERROR; /* Base -> Error */
+
+ t->pl.pmtu = SCTP_MIN_PLPMTU;
+ t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+ sctp_assoc_sync_pmtu(t->asoc);
+ }
+ } else if (t->pl.state == SCTP_PL_SEARCH) {
+ if (t->pl.pmtu == t->pl.probe_size) { /* Black Hole Detected */
+ t->pl.state = SCTP_PL_BASE; /* Search -> Base */
+ t->pl.probe_size = SCTP_BASE_PLPMTU;
+ t->pl.probe_high = 0;
+
+ t->pl.pmtu = SCTP_BASE_PLPMTU;
+ t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+ sctp_assoc_sync_pmtu(t->asoc);
+ } else { /* Normal probe failure. */
+ t->pl.probe_high = t->pl.probe_size;
+ t->pl.probe_size = t->pl.pmtu;
+ }
+ } else if (t->pl.state == SCTP_PL_COMPLETE) {
+ if (t->pl.pmtu == t->pl.probe_size) { /* Black Hole Detected */
+ t->pl.state = SCTP_PL_BASE; /* Search Complete -> Base */
+ t->pl.probe_size = SCTP_BASE_PLPMTU;
+
+ t->pl.pmtu = SCTP_BASE_PLPMTU;
+ t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+ sctp_assoc_sync_pmtu(t->asoc);
+ }
+ }
+ t->pl.probe_count = 1;
+}
+
bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
{
struct dst_entry *dst = sctp_transport_dst_check(t);
The state transition is described in rfc8899#section-5.2, PROBE_COUNT == MAX_PROBES means the probe fails for MAX times, and the state transition includes: - Base -> Error, occurs when BASE_PLPMTU Confirmation Fails, pl.pmtu is set to SCTP_MIN_PLPMTU, probe_size is still SCTP_BASE_PLPMTU; - Search -> Base, occurs when Black Hole Detected, pl.pmtu is set to SCTP_BASE_PLPMTU, probe_size is set back to SCTP_BASE_PLPMTU; - Search Complete -> Base, occurs when Black Hole Detected pl.pmtu is set to SCTP_BASE_PLPMTU, probe_size is set back to SCTP_BASE_PLPMTU; Note a black hole is encountered when a sender is unaware that packets are not being delivered to the destination endpoint. So it includes the probe failures with equal probe_size to pl.pmtu, and definitely not include that with greater probe_size than pl.pmtu. The later one is the normal probe failure where probe_size should decrease back to pl.pmtu and pl.probe_high is set. pl.probe_high would be used on HB ACK recv path in the next patch. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> --- include/net/sctp/structs.h | 1 + net/sctp/sm_statefuns.c | 2 ++ net/sctp/transport.c | 44 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+)