[PATCH 4.19 22/42] Revert "sctp: remove sctp_transport_pmtu_check"

Greg Kroah-Hartman
2018-11-21T19:07:11Z

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit 69fec325a64383667b8a35df5d48d6ce52fb2782 ]

This reverts commit 22d7be267eaa8114dcc28d66c1c347f667d7878a.

The dst's mtu in transport can be updated by a non sctp place like
in xfrm where the MTU information didn't get synced between asoc,
transport and dst, so it is still needed to do the pmtu check
in sctp_packet_config.

Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/sctp/sctp.h | 12 ++++++++++++
net/sctp/output.c | 3 +++
2 files changed, 15 insertions(+)

--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -608,4 +608,16 @@ static inline __u32 sctp_dst_mtu(const s
SCTP_DEFAULT_MINSEGMENT));
}

+static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
+{
+ __u32 pmtu = sctp_dst_mtu(t->dst);
+
+ if (t->pathmtu == pmtu)
+ return true;
+
+ t->pathmtu = pmtu;
+
+ return false;
+}
+
#endif /* __net_sctp_h__ */
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -118,6 +118,9 @@ void sctp_packet_config(struct sctp_pack
sctp_transport_route(tp, NULL, sp);
if (asoc->param_flags & SPP_PMTUD_ENABLE)
sctp_assoc_sync_pmtu(asoc);
+ } else if (!sctp_transport_pmtu_check(tp)) {
+ if (asoc->param_flags & SPP_PMTUD_ENABLE)
+ sctp_assoc_sync_pmtu(asoc);
}

if (asoc->pmtu_pending) {