sctp: Adjust PMTU updates to accomodate route invalidation.

This adjusts the call to dst_ops->update_pmtu() so that we can
transparently handle the fact that, in the future, the dst itself can
be invalidated by the PMTU update (when we have non-host routes cached
in sockets).

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 18 insertions, 10 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index b16517ee1aaf..8cf348e62e74 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1360,7 +1360,7 @@ struct sctp_transport *sctp_assoc_choose_alter_transport(
 /* Update the association's pmtu and frag_point by going through all the
  * transports. This routine is called when a transport's PMTU has changed.
  */
-void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
+void sctp_assoc_sync_pmtu(struct sock *sk, struct sctp_association *asoc)
 {
         struct sctp_transport *t;
         __u32 pmtu = 0;
@@ -1372,7 +1372,7 @@ void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
         list_for_each_entry(t, &asoc->peer.transport_addr_list,
                                 transports) {
                 if (t->pmtu_pending && t->dst) {
-                        sctp_transport_update_pmtu(t, dst_mtu(t->dst));
+                        sctp_transport_update_pmtu(sk, t, dst_mtu(t->dst));
                         t->pmtu_pending = 0;
                 }
                 if (!pmtu || (t->pathmtu < pmtu))
diff --git a/net/sctp/input.c b/net/sctp/input.c
index f050d45faa98..a67bc31f49fd 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -408,10 +408,10 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
 
         if (t->param_flags & SPP_PMTUD_ENABLE) {
                 /* Update transports view of the MTU */
-                sctp_transport_update_pmtu(t, pmtu);
+                sctp_transport_update_pmtu(sk, t, pmtu);
 
                 /* Update association pmtu. */
-                sctp_assoc_sync_pmtu(asoc);
+                sctp_assoc_sync_pmtu(sk, asoc);
         }
 
         /* Retransmit with the new pmtu setting.
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 539f35d07f4e..838e18b4d7ea 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -410,7 +410,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
         if (!sctp_transport_dst_check(tp)) {
                 sctp_transport_route(tp, NULL, sctp_sk(sk));
                 if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) {
-                        sctp_assoc_sync_pmtu(asoc);
+                        sctp_assoc_sync_pmtu(sk, asoc);
                 }
         }
         dst = dst_clone(tp->dst);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index b3b8a8d813eb..74bd3c47350a 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1853,7 +1853,7 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
         }
 
         if (asoc->pmtu_pending)
-                sctp_assoc_pending_pmtu(asoc);
+                sctp_assoc_pending_pmtu(sk, asoc);
 
         /* If fragmentation is disabled and the message length exceeds the
          * association fragmentation point, return EMSGSIZE.  The I-D
@@ -2365,7 +2365,7 @@ static int sctp_apply_peer_addr_params(struct sctp_paddrparams *params,
         if ((params->spp_flags & SPP_PMTUD_DISABLE) && params->spp_pathmtu) {
                 if (trans) {
                         trans->pathmtu = params->spp_pathmtu;
-                        sctp_assoc_sync_pmtu(asoc);
+                        sctp_assoc_sync_pmtu(sctp_opt2sk(sp), asoc);
                 } else if (asoc) {
                         asoc->pathmtu = params->spp_pathmtu;
                         sctp_frag_point(asoc, params->spp_pathmtu);
@@ -2382,7 +2382,7 @@ static int sctp_apply_peer_addr_params(struct sctp_paddrparams *params,
                                 (trans->param_flags & ~SPP_PMTUD) | pmtud_change;
                         if (update) {
                                 sctp_transport_pmtu(trans, sctp_opt2sk(sp));
-                                sctp_assoc_sync_pmtu(asoc);
+                                sctp_assoc_sync_pmtu(sctp_opt2sk(sp), asoc);
                         }
                 } else if (asoc) {
                         asoc->param_flags =
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 1dcceb6e0ce6..e69e1a2175a4 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -228,7 +228,7 @@ 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)
+void sctp_transport_update_pmtu(struct sock *sk, struct sctp_transport *t, u32 pmtu)
 {
         struct dst_entry *dst;
 
@@ -245,8 +245,16 @@ void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
         }
 
         dst = sctp_transport_dst_check(t);
-        if (dst)
+        if (!dst)
+                t->af_specific->get_dst(t, &t->saddr, &t->fl, sk);
+
+        if (dst) {
                 dst->ops->update_pmtu(dst, pmtu);
+
+                dst = sctp_transport_dst_check(t);
+                if (!dst)
+                        t->af_specific->get_dst(t, &t->saddr, &t->fl, sk);
+        }
 }
 
 /* Caches the dst entry and source address for a transport's destination