cregit-Linux how code gets into the kernel

Release 4.17 net/sctp/transport.c

Directory: net/sctp
/* 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 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.
 *
 * 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.
 *
 * 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, see
 * <http://www.gnu.org/licenses/>.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Xingang Guo           <xingang.guo@intel.com>
 *    Hui Huang             <hui.huang@nokia.com>
 *    Sridhar Samudrala     <sri@us.ibm.com>
 *    Ardelle Fan           <ardelle.fan@intel.com>
 */


#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 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);
	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->rto = msecs_to_jiffies(net->sctp.rto_initial);

	peer->last_time_heard = 0;
	peer->last_time_ecne_reduced = jiffies;

	peer->param_flags = SPP_HB_DISABLE |
			    SPP_PMTUD_ENABLE |
			    SPP_SACKDELAY_ENABLE;

	/* Initialize the default path max_retrans.  */
	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);

	timer_setup(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event, 0);
	timer_setup(&peer->hb_timer, sctp_generate_heartbeat_event, 0);
	timer_setup(&peer->reconf_timer, sctp_generate_reconf_event, 0);
	timer_setup(&peer->proto_unreach_timer,
		    sctp_generate_proto_unreach_event, 0);

	/* Initialize the 64-bit random nonce sent with heartbeat. */
	get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));

	refcount_set(&peer->refcnt, 1);

	return peer;
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm11249.12%419.05%


Sridhar Samudrala3314.47%314.29%


Eric W. Biedermann208.77%29.52%


Vladislav Yasevich135.70%29.52%


Neil Horman114.82%29.52%


Xin Long114.82%29.52%


Frank Filz93.95%14.76%


Kees Cook83.51%14.76%


Pavel Emelyanov62.63%14.76%


David S. Miller31.32%14.76%


Elena Reshetova10.44%14.76%


Al Viro10.44%14.76%


Total228100.00%21100.00%



/* Allocate and initialize a new transport.  */



struct sctp_transport *sctp_transport_new(struct net *net,
					  const union sctp_addr *addr,
					  gfp_t gfp)
{
	struct sctp_transport *transport;

	transport = kzalloc(sizeof(*transport), gfp);
	if (!transport)
		goto fail;

	if (!sctp_transport_init(net, transport, addr, gfp))
		goto fail_init;

	SCTP_DBG_OBJCNT_INC(transport);

	return transport;

fail_init:
	kfree(transport);

fail:
	return NULL;
}


Contributors
PersonTokensPropCommitsCommitProp
Sridhar Samudrala7083.33%125.00%


Eric W. Biedermann78.33%125.00%


Daniel Borkmann67.14%125.00%


Al Viro11.19%125.00%


Total84100.00%4100.00%



/* This transport is no longer needed.  Free up if possible, or
 * delay until it last reference count.
 */



void sctp_transport_free(struct sctp_transport *transport)
{
	/* Try to delete the heartbeat timer.  */
	if (del_timer(&transport->hb_timer))
		sctp_transport_put(transport);

	/* Delete the T3_rtx timer if it's active.
         * There is no point in not doing this now and letting
         * structure hang around in memory since we know
         * the tranport is going away.
         */
	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);

	sctp_transport_put(transport);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm2936.25%233.33%


Wei Yongjun1822.50%116.67%


Sridhar Samudrala1620.00%116.67%


Xin Long1518.75%116.67%


David S. Miller22.50%116.67%


Total80100.00%6100.00%






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);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm2044.44%233.33%


Thomas Graf1635.56%116.67%


Sridhar Samudrala817.78%233.33%


David S. Miller12.22%116.67%


Total45100.00%6100.00%



/* Destroy the transport data structure.
 * Assumes there are no more users of this structure.
 */



static void sctp_transport_destroy(struct sctp_transport *transport)
{
	if (unlikely(refcount_read(&transport->refcnt))) {
		WARN(1, "Attempt to destroy undead transport %p!\n", transport);
		return;
	}

	sctp_packet_free(&transport->packet);

	if (transport->asoc)
		sctp_association_put(transport->asoc);

	call_rcu(&transport->rcu, sctp_transport_destroy_rcu);
}


Contributors
PersonTokensPropCommitsCommitProp
Daniel Borkmann4770.15%350.00%


Thomas Graf1522.39%116.67%


Xin Long45.97%116.67%


Elena Reshetova11.49%116.67%


Total67100.00%6100.00%



/* Start T3_rtx timer if it is not already running and update the heartbeat
 * timer.  This routine is called every time a DATA chunk is sent.
 */



void sctp_transport_reset_t3_rtx(struct sctp_transport *transport)
{
	/* RFC 2960 6.3.2 Retransmission Timer Rules
         *
         * R1) Every time a DATA chunk is sent to any address(including a
         * retransmission), if the T3-rtx timer of that address is not running
         * start it running so that it will expire after the RTO of that
         * address.
         */

	if (!timer_pending(&transport->T3_rtx_timer))
		if (!mod_timer(&transport->T3_rtx_timer,
			       jiffies + transport->rto))
			sctp_transport_hold(transport);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm4090.91%250.00%


David S. Miller24.55%125.00%


Marcelo Ricardo Leitner24.55%125.00%


Total44100.00%4100.00%






void sctp_transport_reset_hb_timer(struct sctp_transport *transport)
{
	unsigned long expires;

	/* When a data chunk is sent, reset the heartbeat interval.  */
	expires = jiffies + sctp_transport_timeout(transport);
	if (time_before(transport->hb_timer.expires, expires) &&
	    !mod_timer(&transport->hb_timer,
		       expires + prandom_u32_max(transport->rto)))
		sctp_transport_hold(transport);
}


Contributors
PersonTokensPropCommitsCommitProp
Marcelo Ricardo Leitner3863.33%125.00%


Jon Grimm2135.00%250.00%


David S. Miller11.67%125.00%


Total60100.00%4100.00%






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);
}


Contributors
PersonTokensPropCommitsCommitProp
Xin Long43100.00%1100.00%


Total43100.00%1100.00%



/* 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.
 */



void sctp_transport_set_owner(struct sctp_transport *transport,
			      struct sctp_association *asoc)
{
	transport->asoc = asoc;
	sctp_association_hold(asoc);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm2596.15%375.00%


Sridhar Samudrala13.85%125.00%


Total26100.00%4100.00%



/* Initialize the pmtu of a 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) {
		sctp_transport_dst_release(transport);
		transport->af_specific->get_dst(transport, &transport->saddr,
						&transport->fl, sk);
	}

	if (transport->dst) {
		transport->pathmtu = SCTP_TRUNC4(dst_mtu(transport->dst));
	} else
		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
}


Contributors
PersonTokensPropCommitsCommitProp
Sridhar Samudrala3945.35%111.11%


Vladislav Yasevich3844.19%222.22%


Marcelo Ricardo Leitner33.49%222.22%


Frank Filz22.33%111.11%


David S. Miller22.33%111.11%


Herbert Xu11.16%111.11%


Julian Anastasov11.16%111.11%


Total86100.00%9100.00%






bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
{
	struct dst_entry *dst = sctp_transport_dst_check(t);
	bool change = true;

	if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
		pr_warn_ratelimited("%s: Reported pmtu %d too low, using default minimum of %d\n",
				    __func__, pmtu, SCTP_DEFAULT_MINSEGMENT);
		/* Use default minimum segment instead */
		pmtu = SCTP_DEFAULT_MINSEGMENT;
	}
	pmtu = SCTP_TRUNC4(pmtu);

	if (dst) {
		dst->ops->update_pmtu(dst, t->asoc->base.sk, NULL, pmtu);
		dst = sctp_transport_dst_check(t);
	}

	if (!dst) {
		t->af_specific->get_dst(t, &t->saddr, &t->fl, t->asoc->base.sk);
		dst = t->dst;
	}

	if (dst) {
		/* Re-fetch, as under layers may have a higher minimum size */
		pmtu = SCTP_TRUNC4(dst_mtu(dst));
		change = t->pathmtu != pmtu;
	}
	t->pathmtu = pmtu;

	return change;
}


Contributors
PersonTokensPropCommitsCommitProp
Marcelo Ricardo Leitner5532.35%114.29%


Vladislav Yasevich5230.59%114.29%


David S. Miller4325.29%228.57%


Xin Long1810.59%114.29%


Joe Perches10.59%114.29%


Harvey Harrison10.59%114.29%


Total170100.00%7100.00%



/* Caches the dst entry and source address for a transport's destination
 * address.
 */



void sctp_transport_route(struct sctp_transport *transport,
			  union sctp_addr *saddr, struct sctp_sock *opt)
{
	struct sctp_association *asoc = transport->asoc;
	struct sctp_af *af = transport->af_specific;

	af->get_dst(transport, saddr, &transport->fl, sctp_opt2sk(opt));

	if (saddr)
		memcpy(&transport->saddr, saddr, sizeof(union sctp_addr));
	else
		af->get_saddr(opt, transport, &transport->fl);

	if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) {
		return;
	}
	if (transport->dst) {
		transport->pathmtu = SCTP_TRUNC4(dst_mtu(transport->dst));

		/* Initialize sk->sk_rcv_saddr, if the transport is the
                 * association's active path for getsockname().
                 */
		if (asoc && (!asoc->peer.primary_path ||
				(transport == asoc->peer.active_path)))
			opt->pf->to_sk_saddr(&transport->saddr,
					     asoc->base.sk);
	} else
		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
}


Contributors
PersonTokensPropCommitsCommitProp
Sridhar Samudrala10558.33%418.18%


Vladislav Yasevich2413.33%313.64%


Frank Filz1910.56%14.55%


Jon Grimm168.89%627.27%


Neil Horman42.22%14.55%


David S. Miller42.22%14.55%


Marcelo Ricardo Leitner31.67%29.09%


Hideaki Yoshifuji / 吉藤英明21.11%14.55%


Arnaldo Carvalho de Melo21.11%29.09%


Herbert Xu10.56%14.55%


Total180100.00%22100.00%



/* Hold a reference to a transport.  */



int sctp_transport_hold(struct sctp_transport *transport)
{
	return refcount_inc_not_zero(&transport->refcnt);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm1578.95%250.00%


Xin Long315.79%125.00%


Elena Reshetova15.26%125.00%


Total19100.00%4100.00%



/* Release a reference to a transport and clean up
 * if there are no more references.
 */



void sctp_transport_put(struct sctp_transport *transport)
{
	if (refcount_dec_and_test(&transport->refcnt))
		sctp_transport_destroy(transport);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm2496.00%266.67%


Elena Reshetova14.00%133.33%


Total25100.00%3100.00%



/* Update transport's RTO based on the newly calculated RTT. */



void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
{
	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'
                 */

		/* Note:  The above algorithm has been rewritten to
                 * express rto_beta and rto_alpha as inverse powers
                 * of two.
                 * 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 >> net->sctp.rto_beta)
			+ (((__u32)abs((__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.
                 */
		tp->srtt = rtt;
		tp->rttvar = rtt >> 1;
	}

	/* 6.3.1 G1) Whenever RTTVAR is computed, if RTTVAR = 0, then
         * adjust RTTVAR <- G, where G is the CLOCK GRANULARITY.
         */
	if (tp->rttvar == 0)
		tp->rttvar = SCTP_CLOCK_GRANULARITY;

	/* 6.3.1 C3) After the computation, update RTO <- SRTT + 4 * RTTVAR. */
	tp->rto = tp->srtt + (tp->rttvar << 2);

	/* 6.3.1 C6) Whenever RTO is computed, if it is less than RTO.Min
         * seconds then it is rounded up to RTO.Min seconds.
         */
	if (tp->rto < tp->asoc->rto_min)
		tp->rto = tp->asoc->rto_min;

	/* 6.3.1 C7) A maximum value may be placed on RTO provided it is
         * at least RTO.max seconds.
         */
	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
         * new data chunk is sent.
         */
	tp->rto_pending = 0;

	pr_debug("%s: transport:%p, rtt:%d, srtt:%d rttvar:%d, rto:%ld\n",
		 __func__, tp, rtt, tp->srtt, tp->rttvar, tp->rto);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm20171.28%220.00%


Eric W. Biedermann3612.77%110.00%


Daniel Borkmann155.32%110.00%


David S. Miller103.55%220.00%


Schoch Christian93.19%110.00%


Michele Baldessari93.19%110.00%


Andrew Morton10.35%110.00%


Harvey Harrison10.35%110.00%


Total282100.00%10100.00%



/* This routine updates the transport's cwnd and partial_bytes_acked
 * parameters based on the bytes acked in the received SACK.
 */



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;

	ssthresh = transport->ssthresh;
	pba = transport->partial_bytes_acked;
	pmtu = transport->asoc->pathmtu;

	if (cwnd <= ssthresh) {
		/* 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;

		/* The appropriate cwnd increase algorithm is performed
                 * if, and only if the congestion window is being fully
                 * utilized.  Note that RFC4960 Errata 3.22 removed the
                 * other condition on ctsn moving.
                 */
		if (flight_size < cwnd)
			return;

		if (bytes_acked > pmtu)
			cwnd += pmtu;
		else
			cwnd += bytes_acked;

		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, increase partial_bytes_acked
                 * by the total number of bytes of all new chunks
                 * acknowledged in that SACK including chunks
                 * acknowledged by the new Cumulative TSN Ack and by Gap
                 * Ack Blocks. (updated by RFC4960 Errata 3.22)
                 *
                 * When partial_bytes_acked is greater than cwnd and
                 * before the arrival of the SACK the sender had less
                 * bytes of data outstanding than cwnd (i.e., before
                 * arrival of the SACK, flightsize was less than cwnd),
                 * reset partial_bytes_acked to cwnd. (RFC 4960 Errata
                 * 3.26)
                 *
                 * When partial_bytes_acked is equal to or greater than
                 * cwnd and before the arrival of the SACK the sender
                 * had cwnd or more bytes of data outstanding (i.e.,
                 * before arrival of the SACK, flightsize was greater
                 * than or equal to cwnd), partial_bytes_acked is reset
                 * to (partial_bytes_acked - cwnd). Next, cwnd is
                 * increased by MTU. (RFC 4960 Errata 3.12)
                 */
		pba += bytes_acked;
		if (pba > cwnd && flight_size < cwnd)
			pba = cwnd;
		if (pba >= cwnd && flight_size >= cwnd) {
			pba = pba - cwnd;
			cwnd += pmtu;
		}

		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;
	transport->partial_bytes_acked = pba;
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm14363.27%218.18%


Vladislav Yasevich3716.37%218.18%


Marcelo Ricardo Leitner3113.72%218.18%


Daniel Borkmann73.10%19.09%


David S. Miller52.21%218.18%


Harvey Harrison20.88%19.09%


Frank Filz10.44%19.09%


Total226100.00%11100.00%



/* This routine is used to lower the transport's cwnd when congestion is
 * detected.
 */



void sctp_transport_lower_cwnd(struct sctp_transport *transport,
			       enum sctp_lower_cwnd reason)
{
	struct sctp_association *asoc = transport->asoc;

	switch (reason) {
	case SCTP_LOWER_CWND_T3_RTX:
		/* RFC 2960 Section 7.2.3, sctpimpguide
                 * When the T3-rtx timer expires on an address, SCTP should
                 * perform slow start by:
                 *      ssthresh = max(cwnd/2, 4*MTU)
                 *      cwnd = 1*MTU
                 *      partial_bytes_acked = 0
                 */
		transport->ssthresh = max(transport->cwnd/2,
					  4*asoc->pathmtu);
		transport->cwnd = asoc->pathmtu;

		/* T3-rtx also clears fast recovery */
		asoc->fast_recovery = 0;
		break;

	case SCTP_LOWER_CWND_FAST_RTX:
		/* RFC 2960 7.2.4 Adjust the ssthresh and cwnd of the
                 * 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
                 * 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*asoc->pathmtu);
		transport->cwnd = transport->ssthresh;
		break;

	case SCTP_LOWER_CWND_ECNE:
		/* RFC 2481 Section 6.1.2.
                 * If the sender receives an ECN-Echo ACK packet
                 * then the sender knows that congestion was encountered in the
                 * network on the path from the sender to the receiver. The
                 * indication of congestion should be treated just as a
                 * congestion loss in non-ECN Capable TCP. That is, the TCP
                 * source halves the congestion window "cwnd" and reduces the
                 * slow start threshold "ssthresh".
                 * A critical condition is that TCP does not react to
                 * congestion indications more than once every window of
                 * data (or more loosely more than once every round-trip time).
                 */
		if (time_after(jiffies, transport->last_time_ecne_reduced +
					transport->rtt)) {
			transport->ssthresh = max(transport->cwnd/2,
						  4*asoc->pathmtu);
			transport->cwnd = transport->ssthresh;
			transport->last_time_ecne_reduced = jiffies;
		}
		break;

	case SCTP_LOWER_CWND_INACTIVE:
		/* RFC 2960 Section 7.2.1, sctpimpguide
                 * When the endpoint does not transmit data on a given
                 * transport address, the cwnd of the transport address
                 * should be adjusted to max(cwnd/2, 4*MTU) per RTO.
                 * NOTE: Although the draft recommends that this check needs
                 * to be done every RTO interval, we do it every hearbeat
                 * interval.
                 */
		transport->cwnd = max(transport->cwnd/2,
					 4*asoc->pathmtu);
		/* RFC 4960 Errata 3.27.2: also adjust sshthresh */
		transport->ssthresh = transport->cwnd;
		break;
	}

	transport->partial_bytes_acked = 0;

	pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d\n",
		 __func__, transport, reason, transport->cwnd,
		 transport->ssthresh);
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm15565.40%213.33%


Vladislav Yasevich4016.88%320.00%


Sridhar Samudrala145.91%16.67%


Marcelo Ricardo Leitner93.80%16.67%


Frank Filz52.11%16.67%


Wei Yongjun52.11%16.67%


David S. Miller31.27%213.33%


Daniel Borkmann20.84%16.67%


Xin Long20.84%16.67%


Hideaki Yoshifuji / 吉藤英明10.42%16.67%


Harvey Harrison10.42%16.67%


Total237100.00%15100.00%



/* 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;
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Vladislav Yasevich7292.31%150.00%


Wang Weidong67.69%150.00%


Total78100.00%2100.00%



/* 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;
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Vladislav Yasevich32100.00%1100.00%


Total32100.00%1100.00%



/* What is the next timeout value for this transport? */



unsigned long sctp_transport_timeout(struct sctp_transport *trans)
{
	/* RTO + timer slack +/- 50% of RTO */
	unsigned long timeout = trans->rto >> 1;

	if (trans->state != SCTP_UNCONFIRMED &&
	    trans->state != SCTP_PF)
		timeout += trans->hbinterval;

	return timeout;
}


Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm1840.00%125.00%


Sridhar Samudrala1226.67%125.00%


Daniel Borkmann1022.22%125.00%


Neil Horman511.11%125.00%


Total45100.00%4100.00%



/* 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 variables 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;
}


Contributors
PersonTokensPropCommitsCommitProp
Vladislav Yasevich15395.03%571.43%


Michele Baldessari74.35%114.29%


Masahiro Yamada10.62%114.29%


Total161100.00%7100.00%



/* 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);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Michio Honda7498.67%150.00%


Ying Xue11.33%150.00%


Total75100.00%2100.00%



/* Drop dst */



void sctp_transport_dst_release(struct sctp_transport *t)
{
	dst_release(t->dst);
	t->dst = NULL;
	t->dst_pending_confirm = 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Julian Anastasov29100.00%1100.00%


Total29100.00%1100.00%



/* Schedule neighbour confirm */



void sctp_transport_dst_confirm(struct sctp_transport *t)
{
	t->dst_pending_confirm = 1;
}

Contributors
PersonTokensPropCommitsCommitProp
Julian Anastasov16100.00%1100.00%


Total16100.00%1100.00%




Overall Contributors
PersonTokensPropCommitsCommitProp
Jon Grimm82734.72%78.43%


Vladislav Yasevich46419.48%1315.66%


Sridhar Samudrala30412.76%89.64%


Marcelo Ricardo Leitner1415.92%78.43%


Xin Long964.03%67.23%


Daniel Borkmann873.65%56.02%


David S. Miller833.48%56.02%


Michio Honda753.15%11.20%


Eric W. Biedermann632.64%22.41%


Julian Anastasov482.02%11.20%


Frank Filz361.51%11.20%


Thomas Graf321.34%11.20%


Wei Yongjun230.97%22.41%


Neil Horman200.84%33.61%


Michele Baldessari160.67%11.20%


Schoch Christian90.38%11.20%


Joe Perches80.34%11.20%


Kees Cook80.34%11.20%


Wang Weidong60.25%11.20%


Pavel Emelyanov60.25%11.20%


Harvey Harrison50.21%11.20%


Herbert Xu50.21%22.41%


Elena Reshetova40.17%11.20%


Tejun Heo30.13%11.20%


Hideaki Yoshifuji / 吉藤英明30.13%22.41%


Steven Cole20.08%11.20%


Arnaldo Carvalho de Melo20.08%22.41%


Al Viro20.08%11.20%


Jeff Kirsher10.04%11.20%


Andrew Morton10.04%11.20%


Masahiro Yamada10.04%11.20%


Ying Xue10.04%11.20%


Total2382100.00%83100.00%


Directory: net/sctp



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