1 files changed, 272 insertions, 133 deletions

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 6bc27200e6c..7dd672fa651 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -1,39 +1,35 @@
-/* SCTP kernel reference Implementation
+/* SCTP kernel implementation
  * Copyright (c) 1999-2000 Cisco, Inc.
  * Copyright (c) 1999-2001 Motorola, Inc.
  * Copyright (c) 2001-2003 International Business Machines Corp.
  * Copyright (c) 2001 Intel Corp.
  * Copyright (c) 2001 La Monte H.P. Yarroll
  *
- * This file is part of the SCTP kernel reference Implementation
+ * This file is part of the SCTP kernel implementation
  *
  * This module provides the abstraction for an SCTP tranport representing
  * a remote transport address.  For local transport addresses, we just use
  * union sctp_addr.
  *
- * The SCTP reference implementation is free software;
+ * This SCTP implementation is free software;
  * you can redistribute it and/or modify it under the terms of
  * the GNU General Public License as published by
  * the Free Software Foundation; either version 2, or (at your option)
  * any later version.
  *
- * The SCTP reference implementation is distributed in the hope that it
+ * This SCTP implementation is distributed in the hope that it
  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  *                 ************************
  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  * See the GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with GNU CC; see the file COPYING.  If not, write to
- * the Free Software Foundation, 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * along with GNU CC; see the file COPYING.  If not, see
+ * <http://www.gnu.org/licenses/>.
  *
  * Please send any bug reports or fixes you make to the
  * email address(es):
- *    lksctp developers <lksctp-developers@lists.sourceforge.net>
- *
- * Or submit a bug report through the following website:
- *    http://www.sf.net/projects/lksctp
+ *    lksctp developers <linux-sctp@vger.kernel.org>
  *
  * Written or modified by:
  *    La Monte H.P. Yarroll <piggy@acm.org>
@@ -43,97 +39,83 @@
  *    Hui Huang             <hui.huang@nokia.com>
  *    Sridhar Samudrala	    <sri@us.ibm.com>
  *    Ardelle Fan	    <ardelle.fan@intel.com>
- *
- * Any bugs reported given to us we will try to fix... any fixes shared will
- * be incorporated into the next SCTP release.
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/slab.h>
 #include <linux/types.h>
+#include <linux/random.h>
 #include <net/sctp/sctp.h>
 #include <net/sctp/sm.h>
 
 /* 1st Level Abstractions.  */
 
 /* Initialize a new transport from provided memory.  */
-static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
+static struct sctp_transport *sctp_transport_init(struct net *net,
+						  struct sctp_transport *peer,
 						  const union sctp_addr *addr,
 						  gfp_t gfp)
 {
 	/* Copy in the address.  */
 	peer->ipaddr = *addr;
 	peer->af_specific = sctp_get_af_specific(addr->sa.sa_family);
-	peer->asoc = NULL;
-
-	peer->dst = NULL;
 	memset(&peer->saddr, 0, sizeof(union sctp_addr));
 
+	peer->sack_generation = 0;
+
 	/* From 6.3.1 RTO Calculation:
 	 *
 	 * C1) Until an RTT measurement has been made for a packet sent to the
 	 * given destination transport address, set RTO to the protocol
 	 * parameter 'RTO.Initial'.
 	 */
-	peer->rtt = 0;
-	peer->rto = sctp_rto_initial;
-	peer->rttvar = 0;
-	peer->srtt = 0;
-	peer->rto_pending = 0;
-
-	peer->last_time_heard = jiffies;
-	peer->last_time_used = jiffies;
-	peer->last_time_ecne_reduced = jiffies;
+	peer->rto = msecs_to_jiffies(net->sctp.rto_initial);
 
-	peer->init_sent_count = 0;
+	peer->last_time_heard = ktime_get();
+	peer->last_time_ecne_reduced = jiffies;
 
-	peer->state = SCTP_ACTIVE;
-	peer->hb_allowed = 0;
+	peer->param_flags = SPP_HB_DISABLE |
+			    SPP_PMTUD_ENABLE |
+			    SPP_SACKDELAY_ENABLE;
 
 	/* Initialize the default path max_retrans.  */
-	peer->max_retrans = sctp_max_retrans_path;
-	peer->error_count = 0;
+	peer->pathmaxrxt  = net->sctp.max_retrans_path;
+	peer->pf_retrans  = net->sctp.pf_retrans;
 
 	INIT_LIST_HEAD(&peer->transmitted);
 	INIT_LIST_HEAD(&peer->send_ready);
 	INIT_LIST_HEAD(&peer->transports);
 
-	/* Set up the retransmission timer.  */
-	init_timer(&peer->T3_rtx_timer);
-	peer->T3_rtx_timer.function = sctp_generate_t3_rtx_event;
-	peer->T3_rtx_timer.data = (unsigned long)peer;
+	setup_timer(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event,
+			(unsigned long)peer);
+	setup_timer(&peer->hb_timer, sctp_generate_heartbeat_event,
+			(unsigned long)peer);
+	setup_timer(&peer->proto_unreach_timer,
+		    sctp_generate_proto_unreach_event, (unsigned long)peer);
 
-	/* Set up the heartbeat timer. */
-	init_timer(&peer->hb_timer);
-	peer->hb_timer.function = sctp_generate_heartbeat_event;
-	peer->hb_timer.data = (unsigned long)peer;
+	/* Initialize the 64-bit random nonce sent with heartbeat. */
+	get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));
 
 	atomic_set(&peer->refcnt, 1);
-	peer->dead = 0;
-
-	peer->malloced = 0;
-
-	/* Initialize the state information for SFR-CACC */
-	peer->cacc.changeover_active = 0;
-	peer->cacc.cycling_changeover = 0;
-	peer->cacc.next_tsn_at_change = 0;
-	peer->cacc.cacc_saw_newack = 0;
 
 	return peer;
 }
 
 /* Allocate and initialize a new transport.  */
-struct sctp_transport *sctp_transport_new(const union sctp_addr *addr,
+struct sctp_transport *sctp_transport_new(struct net *net,
+					  const union sctp_addr *addr,
 					  gfp_t gfp)
 {
-        struct sctp_transport *transport;
+	struct sctp_transport *transport;
 
-        transport = t_new(struct sctp_transport, gfp);
+	transport = kzalloc(sizeof(*transport), gfp);
 	if (!transport)
 		goto fail;
 
-	if (!sctp_transport_init(transport, addr, gfp))
+	if (!sctp_transport_init(net, transport, addr, gfp))
 		goto fail_init;
 
-	transport->malloced = 1;
 	SCTP_DBG_OBJCNT_INC(transport);
 
 	return transport;
@@ -161,29 +143,43 @@ void sctp_transport_free(struct sctp_transport *transport)
 	 * structure hang around in memory since we know
 	 * the tranport is going away.
 	 */
-	if (timer_pending(&transport->T3_rtx_timer) &&
-	    del_timer(&transport->T3_rtx_timer))
+	if (del_timer(&transport->T3_rtx_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);
 
 	sctp_transport_put(transport);
 }
 
+static void sctp_transport_destroy_rcu(struct rcu_head *head)
+{
+	struct sctp_transport *transport;
+
+	transport = container_of(head, struct sctp_transport, rcu);
+
+	dst_release(transport->dst);
+	kfree(transport);
+	SCTP_DBG_OBJCNT_DEC(transport);
+}
+
 /* Destroy the transport data structure.
  * Assumes there are no more users of this structure.
  */
 static void sctp_transport_destroy(struct sctp_transport *transport)
 {
-	SCTP_ASSERT(transport->dead, "Transport is not dead", return);
+	if (unlikely(!transport->dead)) {
+		WARN(1, "Attempt to destroy undead transport %p!\n", transport);
+		return;
+	}
+
+	sctp_packet_free(&transport->packet);
 
 	if (transport->asoc)
 		sctp_association_put(transport->asoc);
 
-        sctp_packet_free(&transport->packet);
-
-	dst_release(transport->dst);
-	kfree(transport);
-	SCTP_DBG_OBJCNT_DEC(transport);
+	call_rcu(&transport->rcu, sctp_transport_destroy_rcu);
 }
 
 /* Start T3_rtx timer if it is not already running and update the heartbeat
@@ -222,17 +218,48 @@ void sctp_transport_set_owner(struct sctp_transport *transport,
 }
 
 /* Initialize the pmtu of a transport. */
-void sctp_transport_pmtu(struct sctp_transport *transport)
+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);
+		transport->af_specific->get_dst(transport, &transport->saddr,
+						&transport->fl, sk);
+	}
+
+	if (transport->dst) {
+		transport->pathmtu = dst_mtu(transport->dst);
+	} else
+		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
+}
+
+void sctp_transport_update_pmtu(struct sock *sk, struct sctp_transport *t, u32 pmtu)
 {
 	struct dst_entry *dst;
 
-	dst = transport->af_specific->get_dst(NULL, &transport->ipaddr, NULL);
+	if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
+		pr_warn("%s: Reported pmtu %d too low, using default minimum of %d\n",
+			__func__, pmtu,
+			SCTP_DEFAULT_MINSEGMENT);
+		/* Use default minimum segment size and disable
+		 * pmtu discovery on this transport.
+		 */
+		t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
+	} else {
+		t->pathmtu = pmtu;
+	}
+
+	dst = sctp_transport_dst_check(t);
+	if (!dst)
+		t->af_specific->get_dst(t, &t->saddr, &t->fl, sk);
 
 	if (dst) {
-		transport->pmtu = dst_mtu(dst);
-		dst_release(dst);
-	} else
-		transport->pmtu = SCTP_DEFAULT_MAXSEGMENT;
+		dst->ops->update_pmtu(dst, sk, NULL, 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
@@ -243,27 +270,29 @@ void sctp_transport_route(struct sctp_transport *transport,
 {
 	struct sctp_association *asoc = transport->asoc;
 	struct sctp_af *af = transport->af_specific;
-	union sctp_addr *daddr = &transport->ipaddr;
-	struct dst_entry *dst;
 
-	dst = af->get_dst(asoc, daddr, saddr);
+	af->get_dst(transport, saddr, &transport->fl, sctp_opt2sk(opt));
 
 	if (saddr)
 		memcpy(&transport->saddr, saddr, sizeof(union sctp_addr));
 	else
-		af->get_saddr(asoc, dst, daddr, &transport->saddr);
+		af->get_saddr(opt, transport, &transport->fl);
 
-	transport->dst = dst;
-	if (dst) {
-		transport->pmtu = dst_mtu(dst);
+	if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) {
+		return;
+	}
+	if (transport->dst) {
+		transport->pathmtu = dst_mtu(transport->dst);
 
 		/* Initialize sk->sk_rcv_saddr, if the transport is the
 		 * association's active path for getsockname().
-		 */ 
-		if (asoc && (transport == asoc->peer.active_path))
-			af->to_sk_saddr(&transport->saddr, asoc->base.sk);
+		 */
+		if (asoc && (!asoc->peer.primary_path ||
+				(transport == asoc->peer.active_path)))
+			opt->pf->af->to_sk_saddr(&transport->saddr,
+						 asoc->base.sk);
 	} else
-		transport->pmtu = SCTP_DEFAULT_MAXSEGMENT;
+		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
 }
 
 /* Hold a reference to a transport.  */
@@ -284,13 +313,12 @@ void sctp_transport_put(struct sctp_transport *transport)
 /* Update transport's RTO based on the newly calculated RTT. */
 void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 {
-	/* Check for valid transport.  */
-	SCTP_ASSERT(tp, "NULL transport", return);
-
-	/* We should not be doing any RTO updates unless rto_pending is set.  */
-	SCTP_ASSERT(tp->rto_pending, "rto_pending not set", return);
+	if (unlikely(!tp->rto_pending))
+		/* We should not be doing any RTO updates unless rto_pending is set.  */
+		pr_debug("%s: rto_pending not set on transport %p!\n", __func__, tp);
 
 	if (tp->rttvar || tp->srtt) {
+		struct net *net = sock_net(tp->asoc->base.sk);
 		/* 6.3.1 C3) When a new RTT measurement R' is made, set
 		 * RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'|
 		 * SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R'
@@ -302,10 +330,10 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 		 * For example, assuming the default value of RTO.Alpha of
 		 * 1/8, rto_alpha would be expressed as 3.
 		 */
-		tp->rttvar = tp->rttvar - (tp->rttvar >> sctp_rto_beta)
-			+ ((abs(tp->srtt - rtt)) >> sctp_rto_beta);
-		tp->srtt = tp->srtt - (tp->srtt >> sctp_rto_alpha)
-			+ (rtt >> sctp_rto_alpha);
+		tp->rttvar = tp->rttvar - (tp->rttvar >> net->sctp.rto_beta)
+			+ (((__u32)abs64((__s64)tp->srtt - (__s64)rtt)) >> net->sctp.rto_beta);
+		tp->srtt = tp->srtt - (tp->srtt >> net->sctp.rto_alpha)
+			+ (rtt >> net->sctp.rto_alpha);
 	} else {
 		/* 6.3.1 C2) When the first RTT measurement R is made, set
 		 * SRTT <- R, RTTVAR <- R/2.
@@ -335,6 +363,7 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 	if (tp->rto > tp->asoc->rto_max)
 		tp->rto = tp->asoc->rto_max;
 
+	sctp_max_rto(tp->asoc, tp);
 	tp->rtt = rtt;
 
 	/* Reset rto_pending so that a new RTT measurement is started when a
@@ -342,9 +371,8 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 	 */
 	tp->rto_pending = 0;
 
-	SCTP_DEBUG_PRINTK("%s: transport: %p, rtt: %d, srtt: %d "
-			  "rttvar: %d, rto: %d\n", __FUNCTION__,
-			  tp, rtt, tp->srtt, tp->rttvar, tp->rto);
+	pr_debug("%s: transport:%p, rtt:%d, srtt:%d rttvar:%d, rto:%ld\n",
+		 __func__, tp, rtt, tp->srtt, tp->rttvar, tp->rto);
 }
 
 /* This routine updates the transport's cwnd and partial_bytes_acked
@@ -353,45 +381,56 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 void sctp_transport_raise_cwnd(struct sctp_transport *transport,
 			       __u32 sack_ctsn, __u32 bytes_acked)
 {
+	struct sctp_association *asoc = transport->asoc;
 	__u32 cwnd, ssthresh, flight_size, pba, pmtu;
 
 	cwnd = transport->cwnd;
 	flight_size = transport->flight_size;
 
+	/* See if we need to exit Fast Recovery first */
+	if (asoc->fast_recovery &&
+	    TSN_lte(asoc->fast_recovery_exit, sack_ctsn))
+		asoc->fast_recovery = 0;
+
 	/* The appropriate cwnd increase algorithm is performed if, and only
-	 * if the cumulative TSN has advanced and the congestion window is
+	 * if the cumulative TSN whould advanced and the congestion window is
 	 * being fully utilized.
 	 */
-	if ((transport->asoc->ctsn_ack_point >= sack_ctsn) ||
+	if (TSN_lte(sack_ctsn, transport->asoc->ctsn_ack_point) ||
 	    (flight_size < cwnd))
 		return;
 
 	ssthresh = transport->ssthresh;
 	pba = transport->partial_bytes_acked;
-	pmtu = transport->asoc->pmtu;
+	pmtu = transport->asoc->pathmtu;
 
 	if (cwnd <= ssthresh) {
-		/* RFC 2960 7.2.1, sctpimpguide-05 2.14.2 When cwnd is less
-		 * than or equal to ssthresh an SCTP endpoint MUST use the
-		 * slow start algorithm to increase cwnd only if the current
-		 * congestion window is being fully utilized and an incoming
-		 * SACK advances the Cumulative TSN Ack Point. Only when these
-		 * two conditions are met can the cwnd be increased otherwise
-		 * the cwnd MUST not be increased. If these conditions are met
-		 * then cwnd MUST be increased by at most the lesser of
-		 * 1) the total size of the previously outstanding DATA
-		 * chunk(s) acknowledged, and 2) the destination's path MTU.
+		/* RFC 4960 7.2.1
+		 * o  When cwnd is less than or equal to ssthresh, an SCTP
+		 *    endpoint MUST use the slow-start algorithm to increase
+		 *    cwnd only if the current congestion window is being fully
+		 *    utilized, an incoming SACK advances the Cumulative TSN
+		 *    Ack Point, and the data sender is not in Fast Recovery.
+		 *    Only when these three conditions are met can the cwnd be
+		 *    increased; otherwise, the cwnd MUST not be increased.
+		 *    If these conditions are met, then cwnd MUST be increased
+		 *    by, at most, the lesser of 1) the total size of the
+		 *    previously outstanding DATA chunk(s) acknowledged, and
+		 *    2) the destination's path MTU.  This upper bound protects
+		 *    against the ACK-Splitting attack outlined in [SAVAGE99].
 		 */
+		if (asoc->fast_recovery)
+			return;
+
 		if (bytes_acked > pmtu)
 			cwnd += pmtu;
 		else
 			cwnd += bytes_acked;
-		SCTP_DEBUG_PRINTK("%s: SLOW START: transport: %p, "
-				  "bytes_acked: %d, cwnd: %d, ssthresh: %d, "
-				  "flight_size: %d, pba: %d\n",
-				  __FUNCTION__,
-				  transport, bytes_acked, cwnd,
-				  ssthresh, flight_size, pba);
+
+		pr_debug("%s: slow start: transport:%p, bytes_acked:%d, "
+			 "cwnd:%d, ssthresh:%d, flight_size:%d, pba:%d\n",
+			 __func__, transport, bytes_acked, cwnd, ssthresh,
+			 flight_size, pba);
 	} else {
 		/* RFC 2960 7.2.2 Whenever cwnd is greater than ssthresh,
 		 * upon each SACK arrival that advances the Cumulative TSN Ack
@@ -412,12 +451,12 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport,
 			cwnd += pmtu;
 			pba = ((cwnd < pba) ? (pba - cwnd) : 0);
 		}
-		SCTP_DEBUG_PRINTK("%s: CONGESTION AVOIDANCE: "
-				  "transport: %p, bytes_acked: %d, cwnd: %d, "
-				  "ssthresh: %d, flight_size: %d, pba: %d\n",
-				  __FUNCTION__,
-				  transport, bytes_acked, cwnd,
-				  ssthresh, flight_size, pba);
+
+		pr_debug("%s: congestion avoidance: transport:%p, "
+			 "bytes_acked:%d, cwnd:%d, ssthresh:%d, "
+			 "flight_size:%d, pba:%d\n", __func__,
+			 transport, bytes_acked, cwnd, ssthresh,
+			 flight_size, pba);
 	}
 
 	transport->cwnd = cwnd;
@@ -430,6 +469,8 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport,
 void sctp_transport_lower_cwnd(struct sctp_transport *transport,
 			       sctp_lower_cwnd_t reason)
 {
+	struct sctp_association *asoc = transport->asoc;
+
 	switch (reason) {
 	case SCTP_LOWER_CWND_T3_RTX:
 		/* RFC 2960 Section 7.2.3, sctpimpguide
@@ -440,8 +481,11 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
 		 *      partial_bytes_acked = 0
 		 */
 		transport->ssthresh = max(transport->cwnd/2,
-					  4*transport->asoc->pmtu);
-		transport->cwnd = transport->asoc->pmtu;
+					  4*asoc->pathmtu);
+		transport->cwnd = asoc->pathmtu;
+
+		/* T3-rtx also clears fast recovery */
+		asoc->fast_recovery = 0;
 		break;
 
 	case SCTP_LOWER_CWND_FAST_RTX:
@@ -449,16 +493,23 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
 		 * destination address(es) to which the missing DATA chunks
 		 * were last sent, according to the formula described in
 		 * Section 7.2.3.
-	 	 *
-	 	 * RFC 2960 7.2.3, sctpimpguide Upon detection of packet
+		 *
+		 * RFC 2960 7.2.3, sctpimpguide Upon detection of packet
 		 * losses from SACK (see Section 7.2.4), An endpoint
 		 * should do the following:
 		 *      ssthresh = max(cwnd/2, 4*MTU)
 		 *      cwnd = ssthresh
 		 *      partial_bytes_acked = 0
 		 */
+		if (asoc->fast_recovery)
+			return;
+
+		/* Mark Fast recovery */
+		asoc->fast_recovery = 1;
+		asoc->fast_recovery_exit = asoc->next_tsn - 1;
+
 		transport->ssthresh = max(transport->cwnd/2,
-					  4*transport->asoc->pmtu);
+					  4*asoc->pathmtu);
 		transport->cwnd = transport->ssthresh;
 		break;
 
@@ -475,10 +526,10 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
 		 * congestion indications more than once every window of
 		 * data (or more loosely more than once every round-trip time).
 		 */
-		if ((jiffies - transport->last_time_ecne_reduced) >
-		    transport->rtt) {
+		if (time_after(jiffies, transport->last_time_ecne_reduced +
+					transport->rtt)) {
 			transport->ssthresh = max(transport->cwnd/2,
-					  	  4*transport->asoc->pmtu);
+						  4*asoc->pathmtu);
 			transport->cwnd = transport->ssthresh;
 			transport->last_time_ecne_reduced = jiffies;
 		}
@@ -493,24 +544,112 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
 		 * to be done every RTO interval, we do it every hearbeat
 		 * interval.
 		 */
-		if ((jiffies - transport->last_time_used) > transport->rto)
-			transport->cwnd = max(transport->cwnd/2,
-						 4*transport->asoc->pmtu);
+		transport->cwnd = max(transport->cwnd/2,
+					 4*asoc->pathmtu);
 		break;
-	};
+	}
 
 	transport->partial_bytes_acked = 0;
-	SCTP_DEBUG_PRINTK("%s: transport: %p reason: %d cwnd: "
-			  "%d ssthresh: %d\n", __FUNCTION__,
-			  transport, reason,
-			  transport->cwnd, transport->ssthresh);
+
+	pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d\n",
+		 __func__, transport, reason, transport->cwnd,
+		 transport->ssthresh);
+}
+
+/* Apply Max.Burst limit to the congestion window:
+ * sctpimpguide-05 2.14.2
+ * D) When the time comes for the sender to
+ * transmit new DATA chunks, the protocol parameter Max.Burst MUST
+ * first be applied to limit how many new DATA chunks may be sent.
+ * The limit is applied by adjusting cwnd as follows:
+ * 	if ((flightsize+ Max.Burst * MTU) < cwnd)
+ * 		cwnd = flightsize + Max.Burst * MTU
+ */
+
+void sctp_transport_burst_limited(struct sctp_transport *t)
+{
+	struct sctp_association *asoc = t->asoc;
+	u32 old_cwnd = t->cwnd;
+	u32 max_burst_bytes;
+
+	if (t->burst_limited || asoc->max_burst == 0)
+		return;
+
+	max_burst_bytes = t->flight_size + (asoc->max_burst * asoc->pathmtu);
+	if (max_burst_bytes < old_cwnd) {
+		t->cwnd = max_burst_bytes;
+		t->burst_limited = old_cwnd;
+	}
+}
+
+/* Restore the old cwnd congestion window, after the burst had it's
+ * desired effect.
+ */
+void sctp_transport_burst_reset(struct sctp_transport *t)
+{
+	if (t->burst_limited) {
+		t->cwnd = t->burst_limited;
+		t->burst_limited = 0;
+	}
 }
 
 /* What is the next timeout value for this transport? */
 unsigned long sctp_transport_timeout(struct sctp_transport *t)
 {
 	unsigned long timeout;
-	timeout = t->hb_interval + t->rto + sctp_jitter(t->rto);
+	timeout = t->rto + sctp_jitter(t->rto);
+	if ((t->state != SCTP_UNCONFIRMED) &&
+	    (t->state != SCTP_PF))
+		timeout += t->hbinterval;
 	timeout += jiffies;
 	return timeout;
 }
+
+/* Reset transport variables to their initial values */
+void sctp_transport_reset(struct sctp_transport *t)
+{
+	struct sctp_association *asoc = t->asoc;
+
+	/* RFC 2960 (bis), Section 5.2.4
+	 * All the congestion control parameters (e.g., cwnd, ssthresh)
+	 * related to this peer MUST be reset to their initial values
+	 * (see Section 6.2.1)
+	 */
+	t->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
+	t->burst_limited = 0;
+	t->ssthresh = asoc->peer.i.a_rwnd;
+	t->rto = asoc->rto_initial;
+	sctp_max_rto(asoc, t);
+	t->rtt = 0;
+	t->srtt = 0;
+	t->rttvar = 0;
+
+	/* Reset these additional varibles so that we have a clean
+	 * slate.
+	 */
+	t->partial_bytes_acked = 0;
+	t->flight_size = 0;
+	t->error_count = 0;
+	t->rto_pending = 0;
+	t->hb_sent = 0;
+
+	/* Initialize the state information for SFR-CACC */
+	t->cacc.changeover_active = 0;
+	t->cacc.cycling_changeover = 0;
+	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 (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);
+	}
+}