sctp: fasthandoff with ASCONF at mobile-node

Fast retransmission after changing the last address
with ASCONF negotiation

Signed-off-by: Michio Honda <micchie@sfc.wide.ad.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 20 insertions, 1 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index e90e7a9935dd..3382615bd710 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1085,6 +1085,7 @@ void sctp_transport_burst_reset(struct sctp_transport *);
 unsigned long sctp_transport_timeout(struct sctp_transport *);
 void sctp_transport_reset(struct sctp_transport *);
 void sctp_transport_update_pmtu(struct sctp_transport *, u32);
+void sctp_transport_immediate_rtx(struct sctp_transport *);
 
 
 /* This is the structure we use to queue packets as they come into
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 0121e0ab0351..a85eeeb55dd0 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3400,8 +3400,10 @@ int sctp_process_asconf_ack(struct sctp_association *asoc,
                 asconf_len -= length;
         }
 
-        if (no_err && asoc->src_out_of_asoc_ok)
+        if (no_err && asoc->src_out_of_asoc_ok) {
                 asoc->src_out_of_asoc_ok = 0;
+                sctp_transport_immediate_rtx(asoc->peer.primary_path);
+        }
 
         /* Free the cached last sent asconf chunk. */
         list_del_init(&asconf->transmitted_list);
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 394c57ca2f54..3889330b7b04 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -641,3 +641,19 @@ void sctp_transport_reset(struct sctp_transport *t)
         t->cacc.next_tsn_at_change = 0;
         t->cacc.cacc_saw_newack = 0;
 }
+
+/* Schedule retransmission on the given transport */
+void sctp_transport_immediate_rtx(struct sctp_transport *t)
+{
+        /* Stop pending T3_rtx_timer */
+        if (timer_pending(&t->T3_rtx_timer)) {
+                (void)del_timer(&t->T3_rtx_timer);
+                sctp_transport_put(t);
+        }
+        sctp_retransmit(&t->asoc->outqueue, t, SCTP_RTXR_T3_RTX);
+        if (!timer_pending(&t->T3_rtx_timer)) {
+                if (!mod_timer(&t->T3_rtx_timer, jiffies + t->rto))
+                        sctp_transport_hold(t);
+        }
+        return;
+}