sctp: add stream reconf timer

This patch is to add a per transport timer based on sctp timer frame
for stream reconf chunk retransmission. It would start after sending
a reconf request chunk, and stop after receiving the response chunk.

If the timer expires, besides retransmitting the reconf request chunk,
it would also do the same thing with data RTO timer. like to increase
the appropriate error counts, and perform threshold management, possibly
destroying the asoc if sctp retransmission thresholds are exceeded, just
as section 5.1.1 describes.

This patch is also to add asoc strreset_chunk, it is used to save the
reconf request chunk, so that it can be retransmitted, and to check if
the response is really for this request by comparing the information
inside with the response chunk as well.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 104 insertions, 2 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 42ece6f35b98..fc33540d2f11 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -362,6 +362,9 @@ void sctp_association_free(struct sctp_association *asoc)
 	/* Free stream information. */
 	sctp_stream_free(asoc->stream);
 
+	if (asoc->strreset_chunk)
+		sctp_chunk_free(asoc->strreset_chunk);
+
 	/* Clean up the bound address list. */
 	sctp_bind_addr_free(&asoc->base.bind_addr);
 
@@ -520,6 +523,12 @@ void sctp_assoc_rm_peer(struct sctp_association *asoc,
 	if (asoc->peer.last_data_from == peer)
 		asoc->peer.last_data_from = transport;
 
+	if (asoc->strreset_chunk &&
+	    asoc->strreset_chunk->transport == peer) {
+		asoc->strreset_chunk->transport = transport;
+		sctp_transport_reset_reconf_timer(transport);
+	}
+
 	/* If we remove the transport an INIT was last sent to, set it to
 	 * NULL. Combined with the update of the retran path above, this
 	 * will cause the next INIT to be sent to the next available
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index c345bf153bed..a4552712b882 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -436,6 +436,37 @@ out_unlock:
 	sctp_association_put(asoc);
 }
 
+ /* Handle the timeout of the RE-CONFIG timer. */
+void sctp_generate_reconf_event(unsigned long data)
+{
+	struct sctp_transport *transport = (struct sctp_transport *)data;
+	struct sctp_association *asoc = transport->asoc;
+	struct sock *sk = asoc->base.sk;
+	struct net *net = sock_net(sk);
+	int error = 0;
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		pr_debug("%s: sock is busy\n", __func__);
+
+		/* Try again later.  */
+		if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
+			sctp_transport_hold(transport);
+		goto out_unlock;
+	}
+
+	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
+			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
+			   asoc->state, asoc->ep, asoc,
+			   transport, GFP_ATOMIC);
+
+	if (error)
+		sk->sk_err = -error;
+
+out_unlock:
+	bh_unlock_sock(sk);
+	sctp_transport_put(transport);
+}
 
 /* Inject a SACK Timeout event into the state machine.  */
 static void sctp_generate_sack_event(unsigned long data)
@@ -453,6 +484,7 @@ sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 	sctp_generate_t4_rto_event,
 	sctp_generate_t5_shutdown_guard_event,
 	NULL,
+	NULL,
 	sctp_generate_sack_event,
 	sctp_generate_autoclose_event,
 };
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 0ceded37d20b..2ae186aba9a8 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1021,6 +1021,34 @@ sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
 	return SCTP_DISPOSITION_CONSUME;
 }
 
+/* resend asoc strreset_chunk.  */
+sctp_disposition_t sctp_sf_send_reconf(struct net *net,
+				       const struct sctp_endpoint *ep,
+				       const struct sctp_association *asoc,
+				       const sctp_subtype_t type, void *arg,
+				       sctp_cmd_seq_t *commands)
+{
+	struct sctp_transport *transport = arg;
+
+	if (asoc->overall_error_count >= asoc->max_retrans) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+				SCTP_ERROR(ETIMEDOUT));
+		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
+		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+				SCTP_PERR(SCTP_ERROR_NO_ERROR));
+		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
+		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
+		return SCTP_DISPOSITION_DELETE_TCB;
+	}
+
+	sctp_chunk_hold(asoc->strreset_chunk);
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
+			SCTP_CHUNK(asoc->strreset_chunk));
+	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
+
+	return SCTP_DISPOSITION_CONSUME;
+}
+
 /*
  * Process an heartbeat request.
  *
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index a987d54b379c..3da521abfc57 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -888,6 +888,25 @@ static const sctp_sm_table_entry_t other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_
 	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
 }
 
+#define TYPE_SCTP_EVENT_TIMEOUT_RECONF { \
+	/* SCTP_STATE_CLOSED */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+	/* SCTP_STATE_COOKIE_WAIT */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+	/* SCTP_STATE_COOKIE_ECHOED */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+	/* SCTP_STATE_ESTABLISHED */ \
+	TYPE_SCTP_FUNC(sctp_sf_send_reconf), \
+	/* SCTP_STATE_SHUTDOWN_PENDING */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+	/* SCTP_STATE_SHUTDOWN_SENT */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+	/* SCTP_STATE_SHUTDOWN_RECEIVED */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+	/* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
+	TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+}
+
 static const sctp_sm_table_entry_t timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
 	TYPE_SCTP_EVENT_TIMEOUT_NONE,
 	TYPE_SCTP_EVENT_TIMEOUT_T1_COOKIE,
@@ -897,6 +916,7 @@ static const sctp_sm_table_entry_t timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][S
 	TYPE_SCTP_EVENT_TIMEOUT_T4_RTO,
 	TYPE_SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
 	TYPE_SCTP_EVENT_TIMEOUT_HEARTBEAT,
+	TYPE_SCTP_EVENT_TIMEOUT_RECONF,
 	TYPE_SCTP_EVENT_TIMEOUT_SACK,
 	TYPE_SCTP_EVENT_TIMEOUT_AUTOCLOSE,
 };
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index a1652ab63918..baa1ac00d7b5 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -88,9 +88,11 @@ static struct sctp_transport *sctp_transport_init(struct net *net,
 	INIT_LIST_HEAD(&peer->transports);
 
 	setup_timer(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event,
-			(unsigned long)peer);
+		    (unsigned long)peer);
 	setup_timer(&peer->hb_timer, sctp_generate_heartbeat_event,
-			(unsigned long)peer);
+		    (unsigned long)peer);
+	setup_timer(&peer->reconf_timer, sctp_generate_reconf_event,
+		    (unsigned long)peer);
 	setup_timer(&peer->proto_unreach_timer,
 		    sctp_generate_proto_unreach_event, (unsigned long)peer);
 
@@ -144,6 +146,9 @@ void sctp_transport_free(struct sctp_transport *transport)
 	if (del_timer(&transport->T3_rtx_timer))
 		sctp_transport_put(transport);
 
+	if (del_timer(&transport->reconf_timer))
+		sctp_transport_put(transport);
+
 	/* Delete the ICMP proto unreachable timer if it's active. */
 	if (del_timer(&transport->proto_unreach_timer))
 		sctp_association_put(transport->asoc);
@@ -211,6 +216,14 @@ void sctp_transport_reset_hb_timer(struct sctp_transport *transport)
 		sctp_transport_hold(transport);
 }
 
+void sctp_transport_reset_reconf_timer(struct sctp_transport *transport)
+{
+	if (!timer_pending(&transport->reconf_timer))
+		if (!mod_timer(&transport->reconf_timer,
+			       jiffies + transport->rto))
+			sctp_transport_hold(transport);
+}
+
 /* This transport has been assigned to an association.
  * Initialize fields from the association or from the sock itself.
  * Register the reference count in the association.