sctp: do not update transport pathmtu if SPP_PMTUD_ENABLE is not set

Currently, in sctp_packet_config(), sctp_transport_pmtu_check() is
called to update transport pathmtu with dst's mtu when dst's mtu
has been changed by non sctp stack like xfrm.

However, this should only happen when SPP_PMTUD_ENABLE is set, no
matter where dst's mtu changed. This patch is to fix by checking
SPP_PMTUD_ENABLE flag before calling sctp_transport_pmtu_check().

Thanks Jacek for reporting and looking into this issue.

v1->v2:
  - add the missing "{" to fix the build error.

Fixes: 69fec325a643 ('Revert "sctp: remove sctp_transport_pmtu_check"')
Reported-by: Jacek Szafraniec <jacek.szafraniec@nokia.com>
Tested-by: Jacek Szafraniec <jacek.szafraniec@nokia.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/output.c b/net/sctp/output.c
index 9032ce60d50e81be8c6adfbf72df32f968a6a2fc..4dfb5ea82b05b08386a2d7018cd6417c0ec6ba5a 100644 (file)
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -104,8 +104,8 @@ void sctp_packet_config(struct sctp_packet *packet, __u32 vtag,
                if (asoc->param_flags & SPP_PMTUD_ENABLE)
                        sctp_assoc_sync_pmtu(asoc);
        } else if (!sctp_transport_pl_enabled(tp) &&
-                  !sctp_transport_pmtu_check(tp)) {
-               if (asoc->param_flags & SPP_PMTUD_ENABLE)
+                  asoc->param_flags & SPP_PMTUD_ENABLE) {
+               if (!sctp_transport_pmtu_check(tp))
                        sctp_assoc_sync_pmtu(asoc);
        }