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authorXin Long <lucien.xin@gmail.com>2023-05-18 16:03:00 -0400
committerDavid S. Miller <davem@davemloft.net>2023-05-22 11:05:20 +0100
commit6ca328e985cd995dfd1d5de44046e6074f853fbb (patch)
tree1441fe2d6325c8626318e159b078075a4411ce4f /net
parent67caf26d769e0cb17dba182b0acae015c7aa5881 (diff)
sctp: fix an issue that plpmtu can never go to complete state
When doing plpmtu probe, the probe size is growing every time when it receives the ACK during the Search state until the probe fails. When the failure occurs, pl.probe_high is set and it goes to the Complete state. However, if the link pmtu is huge, like 65535 in loopback_dev, the probe eventually keeps using SCTP_MAX_PLPMTU as the probe size and never fails. Because of that, pl.probe_high can not be set, and the plpmtu probe can never go to the Complete state. Fix it by setting pl.probe_high to SCTP_MAX_PLPMTU when the probe size grows to SCTP_MAX_PLPMTU in sctp_transport_pl_recv(). Also, not allow the probe size greater than SCTP_MAX_PLPMTU in the Complete state. Fixes: b87641aff9e7 ("sctp: do state transition when a probe succeeds on HB ACK recv path") Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/transport.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 2f66a2006517..2abe45af98e7 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -324,9 +324,12 @@ bool sctp_transport_pl_recv(struct sctp_transport *t)
t->pl.probe_size += SCTP_PL_BIG_STEP;
} else if (t->pl.state == SCTP_PL_SEARCH) {
if (!t->pl.probe_high) {
- t->pl.probe_size = min(t->pl.probe_size + SCTP_PL_BIG_STEP,
- SCTP_MAX_PLPMTU);
- return false;
+ if (t->pl.probe_size < SCTP_MAX_PLPMTU) {
+ t->pl.probe_size = min(t->pl.probe_size + SCTP_PL_BIG_STEP,
+ SCTP_MAX_PLPMTU);
+ return false;
+ }
+ t->pl.probe_high = SCTP_MAX_PLPMTU;
}
t->pl.probe_size += SCTP_PL_MIN_STEP;
if (t->pl.probe_size >= t->pl.probe_high) {
@@ -341,7 +344,7 @@ bool sctp_transport_pl_recv(struct sctp_transport *t)
} else if (t->pl.state == SCTP_PL_COMPLETE) {
/* Raise probe_size again after 30 * interval in Search Complete */
t->pl.state = SCTP_PL_SEARCH; /* Search Complete -> Search */
- t->pl.probe_size += SCTP_PL_MIN_STEP;
+ t->pl.probe_size = min(t->pl.probe_size + SCTP_PL_MIN_STEP, SCTP_MAX_PLPMTU);
}
return t->pl.state == SCTP_PL_COMPLETE;