[PATCHv4 net-next 3/7] sctp: add dst_pending_confirm flag

[Julian Anastasov <ja@ssi.bg>]

Add new transport flag to allow sockets to confirm neighbour.
When same struct dst_entry can be used for many different
neighbours we can not use it for pending confirmations.
The flag is propagated from transport to every packet.
It is reset when cached dst is reset.

Reported-by: YueHaibing <yuehaibing@huawei.com>
Fixes: 5110effee8fd ("net: Do delayed neigh confirmation.")
Fixes: f2bb4bedf35d ("ipv4: Cache output routes in fib_info nexthops.")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
---
 include/net/sctp/sctp.h    |  6 ++----
 include/net/sctp/structs.h |  4 ++++
 net/sctp/associola.c       |  3 +--
 net/sctp/output.c          | 10 +++++++++-
 net/sctp/outqueue.c        |  2 +-
 net/sctp/sm_make_chunk.c   |  6 ++----
 net/sctp/sm_sideeffect.c   |  2 +-
 net/sctp/socket.c          |  4 ++--
 net/sctp/transport.c       | 17 ++++++++++++++++-
 9 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 3cfd365b..480b65a 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -593,10 +593,8 @@ static inline void sctp_v4_map_v6(union sctp_addr *addr)
  */
 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
 {
-	if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
-		dst_release(t->dst);
-		t->dst = NULL;
-	}
+	if (t->dst && !dst_check(t->dst, t->dst_cookie))
+		sctp_transport_dst_release(t);
 
 	return t->dst;
 }
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 231fa9ac..6a68504 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -804,6 +804,8 @@ struct sctp_transport {
 
 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
 
+	__u32 dst_pending_confirm;	/* need to confirm neighbour */
+
 	/* Destination */
 	struct dst_entry *dst;
 	/* Source address. */
@@ -950,6 +952,8 @@ void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
 void sctp_transport_reset(struct sctp_transport *);
 void sctp_transport_update_pmtu(struct sock *, struct sctp_transport *, u32);
 void sctp_transport_immediate_rtx(struct sctp_transport *);
+void sctp_transport_dst_release(struct sctp_transport *t);
+void sctp_transport_dst_confirm(struct sctp_transport *t);
 
 
 /* This is the structure we use to queue packets as they come into
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index e50dc6d..2a6835b 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -832,8 +832,7 @@ void sctp_assoc_control_transport(struct sctp_association *asoc,
 		if (transport->state != SCTP_UNCONFIRMED)
 			transport->state = SCTP_INACTIVE;
 		else {
-			dst_release(transport->dst);
-			transport->dst = NULL;
+			sctp_transport_dst_release(transport);
 			ulp_notify = false;
 		}
 
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 07ab506..814eac0 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -546,6 +546,7 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
 	struct sctp_association *asoc = tp->asoc;
 	struct sctp_chunk *chunk, *tmp;
 	int pkt_count, gso = 0;
+	int confirm;
 	struct dst_entry *dst;
 	struct sk_buff *head;
 	struct sctphdr *sh;
@@ -624,7 +625,14 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
 			asoc->peer.last_sent_to = tp;
 	}
 	head->ignore_df = packet->ipfragok;
-	tp->af_specific->sctp_xmit(head, tp);
+	confirm = tp->dst_pending_confirm;
+	if (confirm)
+		skb_set_dst_pending_confirm(head, 1);
+	/* neighbour should be confirmed on successful transmission or
+	 * positive error
+	 */
+	if (tp->af_specific->sctp_xmit(head, tp) >= 0 && confirm)
+		tp->dst_pending_confirm = 0;
 
 out:
 	list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 65abe22..db352e5 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -1654,7 +1654,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 
 		if (forward_progress) {
 			if (transport->dst)
-				dst_confirm(transport->dst);
+				sctp_transport_dst_confirm(transport);
 		}
 	}
 
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index ad3445b..c7d3249 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3333,8 +3333,7 @@ static void sctp_asconf_param_success(struct sctp_association *asoc,
 		local_bh_enable();
 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
 				transports) {
-			dst_release(transport->dst);
-			transport->dst = NULL;
+			sctp_transport_dst_release(transport);
 		}
 		break;
 	case SCTP_PARAM_DEL_IP:
@@ -3348,8 +3347,7 @@ static void sctp_asconf_param_success(struct sctp_association *asoc,
 		local_bh_enable();
 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
 				transports) {
-			dst_release(transport->dst);
-			transport->dst = NULL;
+			sctp_transport_dst_release(transport);
 		}
 		break;
 	default:
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index a455271..51abcc9 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -755,7 +755,7 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 	 * forward progress.
 	 */
 	if (t->dst)
-		dst_confirm(t->dst);
+		sctp_transport_dst_confirm(t);
 
 	/* The receiver of the HEARTBEAT ACK should also perform an
 	 * RTT measurement for that destination transport address
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 5fc7122..a4609a0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -592,7 +592,7 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
 			list_for_each_entry(trans,
 			    &asoc->peer.transport_addr_list, transports) {
 				/* Clear the source and route cache */
-				dst_release(trans->dst);
+				sctp_transport_dst_release(trans);
 				trans->cwnd = min(4*asoc->pathmtu, max_t(__u32,
 				    2*asoc->pathmtu, 4380));
 				trans->ssthresh = asoc->peer.i.a_rwnd;
@@ -843,7 +843,7 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
 		 */
 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
 					transports) {
-			dst_release(transport->dst);
+			sctp_transport_dst_release(transport);
 			sctp_transport_route(transport, NULL,
 					     sctp_sk(asoc->base.sk));
 		}
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index baa1ac0..df274ff 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -240,7 +240,7 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 {
 	/* If we don't have a fresh route, look one up */
 	if (!transport->dst || transport->dst->obsolete) {
-		dst_release(transport->dst);
+		sctp_transport_dst_release(transport);
 		transport->af_specific->get_dst(transport, &transport->saddr,
 						&transport->fl, sk);
 	}
@@ -672,3 +672,18 @@ void sctp_transport_immediate_rtx(struct sctp_transport *t)
 			sctp_transport_hold(t);
 	}
 }
+
+/* Drop dst */
+void sctp_transport_dst_release(struct sctp_transport *t)
+{
+	dst_release(t->dst);
+	t->dst = NULL;
+	t->dst_pending_confirm = 0;
+}
+
+/* Schedule neighbour confirm */
+void sctp_transport_dst_confirm(struct sctp_transport *t)
+{
+	t->dst_pending_confirm = 1;
+}
+
-- 
1.9.3