2005-04-16 16:20:36 -06:00
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/* SCTP kernel reference Implementation
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* Copyright (c) 1999-2000 Cisco, Inc.
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* Copyright (c) 1999-2001 Motorola, Inc.
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* Copyright (c) 2001-2003 International Business Machines Corp.
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* Copyright (c) 2001 Intel Corp.
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* Copyright (c) 2001 La Monte H.P. Yarroll
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*
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* This file is part of the SCTP kernel reference Implementation
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*
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* This module provides the abstraction for an SCTP tranport representing
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* a remote transport address. For local transport addresses, we just use
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* union sctp_addr.
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*
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* The SCTP reference implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* The SCTP reference implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <lksctp-developers@lists.sourceforge.net>
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*
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* Or submit a bug report through the following website:
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* http://www.sf.net/projects/lksctp
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*
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* Written or modified by:
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* La Monte H.P. Yarroll <piggy@acm.org>
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* Karl Knutson <karl@athena.chicago.il.us>
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* Jon Grimm <jgrimm@us.ibm.com>
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* Xingang Guo <xingang.guo@intel.com>
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* Hui Huang <hui.huang@nokia.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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* Ardelle Fan <ardelle.fan@intel.com>
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*
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* Any bugs reported given to us we will try to fix... any fixes shared will
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* be incorporated into the next SCTP release.
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*/
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#include <linux/types.h>
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2006-07-21 15:48:50 -06:00
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#include <linux/random.h>
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2005-04-16 16:20:36 -06:00
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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/* 1st Level Abstractions. */
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/* Initialize a new transport from provided memory. */
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static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
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const union sctp_addr *addr,
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2005-10-07 00:46:04 -06:00
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gfp_t gfp)
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2005-04-16 16:20:36 -06:00
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{
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/* Copy in the address. */
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2006-11-20 18:10:03 -07:00
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peer->ipaddr = *addr;
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2005-04-16 16:20:36 -06:00
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peer->af_specific = sctp_get_af_specific(addr->sa.sa_family);
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peer->asoc = NULL;
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peer->dst = NULL;
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2006-11-20 18:04:42 -07:00
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memset(&peer->saddr, 0, sizeof(union sctp_addr));
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2005-04-16 16:20:36 -06:00
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/* From 6.3.1 RTO Calculation:
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*
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* C1) Until an RTT measurement has been made for a packet sent to the
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* given destination transport address, set RTO to the protocol
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* parameter 'RTO.Initial'.
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*/
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peer->rtt = 0;
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2006-08-22 14:29:17 -06:00
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peer->rto = msecs_to_jiffies(sctp_rto_initial);
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2005-04-16 16:20:36 -06:00
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peer->rttvar = 0;
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peer->srtt = 0;
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peer->rto_pending = 0;
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peer->last_time_heard = jiffies;
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peer->last_time_used = jiffies;
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peer->last_time_ecne_reduced = jiffies;
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2005-06-20 14:14:57 -06:00
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peer->init_sent_count = 0;
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2005-12-22 12:36:46 -07:00
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peer->param_flags = SPP_HB_DISABLE |
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SPP_PMTUD_ENABLE |
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SPP_SACKDELAY_ENABLE;
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peer->hbinterval = 0;
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2005-04-16 16:20:36 -06:00
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/* Initialize the default path max_retrans. */
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2005-12-22 12:36:46 -07:00
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peer->pathmaxrxt = sctp_max_retrans_path;
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2005-04-16 16:20:36 -06:00
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peer->error_count = 0;
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INIT_LIST_HEAD(&peer->transmitted);
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INIT_LIST_HEAD(&peer->send_ready);
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INIT_LIST_HEAD(&peer->transports);
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/* Set up the retransmission timer. */
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init_timer(&peer->T3_rtx_timer);
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peer->T3_rtx_timer.function = sctp_generate_t3_rtx_event;
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peer->T3_rtx_timer.data = (unsigned long)peer;
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/* Set up the heartbeat timer. */
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init_timer(&peer->hb_timer);
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peer->hb_timer.function = sctp_generate_heartbeat_event;
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peer->hb_timer.data = (unsigned long)peer;
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2006-07-21 15:48:50 -06:00
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/* Initialize the 64-bit random nonce sent with heartbeat. */
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get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));
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2005-04-16 16:20:36 -06:00
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atomic_set(&peer->refcnt, 1);
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peer->dead = 0;
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peer->malloced = 0;
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/* Initialize the state information for SFR-CACC */
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peer->cacc.changeover_active = 0;
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peer->cacc.cycling_changeover = 0;
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peer->cacc.next_tsn_at_change = 0;
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peer->cacc.cacc_saw_newack = 0;
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return peer;
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}
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/* Allocate and initialize a new transport. */
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2005-07-11 21:57:47 -06:00
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struct sctp_transport *sctp_transport_new(const union sctp_addr *addr,
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2005-10-07 00:46:04 -06:00
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gfp_t gfp)
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2005-04-16 16:20:36 -06:00
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{
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struct sctp_transport *transport;
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transport = t_new(struct sctp_transport, gfp);
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if (!transport)
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goto fail;
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if (!sctp_transport_init(transport, addr, gfp))
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goto fail_init;
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transport->malloced = 1;
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SCTP_DBG_OBJCNT_INC(transport);
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return transport;
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fail_init:
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kfree(transport);
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fail:
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return NULL;
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}
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/* This transport is no longer needed. Free up if possible, or
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* delay until it last reference count.
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*/
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void sctp_transport_free(struct sctp_transport *transport)
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{
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transport->dead = 1;
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/* Try to delete the heartbeat timer. */
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if (del_timer(&transport->hb_timer))
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sctp_transport_put(transport);
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/* Delete the T3_rtx timer if it's active.
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* There is no point in not doing this now and letting
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* structure hang around in memory since we know
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* the tranport is going away.
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*/
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if (timer_pending(&transport->T3_rtx_timer) &&
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del_timer(&transport->T3_rtx_timer))
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sctp_transport_put(transport);
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sctp_transport_put(transport);
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}
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/* Destroy the transport data structure.
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* Assumes there are no more users of this structure.
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*/
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static void sctp_transport_destroy(struct sctp_transport *transport)
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{
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SCTP_ASSERT(transport->dead, "Transport is not dead", return);
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if (transport->asoc)
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sctp_association_put(transport->asoc);
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sctp_packet_free(&transport->packet);
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dst_release(transport->dst);
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kfree(transport);
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SCTP_DBG_OBJCNT_DEC(transport);
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}
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/* Start T3_rtx timer if it is not already running and update the heartbeat
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* timer. This routine is called every time a DATA chunk is sent.
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*/
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void sctp_transport_reset_timers(struct sctp_transport *transport)
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{
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/* RFC 2960 6.3.2 Retransmission Timer Rules
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*
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* R1) Every time a DATA chunk is sent to any address(including a
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* retransmission), if the T3-rtx timer of that address is not running
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* start it running so that it will expire after the RTO of that
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* address.
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*/
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if (!timer_pending(&transport->T3_rtx_timer))
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if (!mod_timer(&transport->T3_rtx_timer,
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jiffies + transport->rto))
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sctp_transport_hold(transport);
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/* When a data chunk is sent, reset the heartbeat interval. */
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if (!mod_timer(&transport->hb_timer,
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sctp_transport_timeout(transport)))
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sctp_transport_hold(transport);
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}
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/* This transport has been assigned to an association.
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* Initialize fields from the association or from the sock itself.
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* Register the reference count in the association.
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*/
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void sctp_transport_set_owner(struct sctp_transport *transport,
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struct sctp_association *asoc)
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{
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transport->asoc = asoc;
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sctp_association_hold(asoc);
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}
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/* Initialize the pmtu of a transport. */
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void sctp_transport_pmtu(struct sctp_transport *transport)
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{
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struct dst_entry *dst;
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2006-11-20 18:13:01 -07:00
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dst = transport->af_specific->get_dst(NULL, &transport->ipaddr, NULL);
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2005-04-16 16:20:36 -06:00
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if (dst) {
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2005-12-22 12:36:46 -07:00
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transport->pathmtu = dst_mtu(dst);
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2005-04-16 16:20:36 -06:00
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dst_release(dst);
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} else
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2005-12-22 12:36:46 -07:00
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transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
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2005-04-16 16:20:36 -06:00
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}
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/* Caches the dst entry and source address for a transport's destination
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* address.
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*/
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void sctp_transport_route(struct sctp_transport *transport,
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union sctp_addr *saddr, struct sctp_sock *opt)
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{
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struct sctp_association *asoc = transport->asoc;
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struct sctp_af *af = transport->af_specific;
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2006-11-20 18:13:01 -07:00
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union sctp_addr *daddr = &transport->ipaddr;
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2005-04-16 16:20:36 -06:00
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struct dst_entry *dst;
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2006-11-20 18:13:21 -07:00
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dst = af->get_dst(asoc, daddr, saddr);
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2005-04-16 16:20:36 -06:00
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2006-11-20 18:13:21 -07:00
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if (saddr)
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memcpy(&transport->saddr, saddr, sizeof(union sctp_addr));
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else
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2006-11-20 18:13:01 -07:00
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af->get_saddr(asoc, dst, daddr, &transport->saddr);
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2005-04-16 16:20:36 -06:00
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transport->dst = dst;
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2005-12-22 12:36:46 -07:00
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if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) {
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return;
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}
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2005-04-16 16:20:36 -06:00
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if (dst) {
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2005-12-22 12:36:46 -07:00
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transport->pathmtu = dst_mtu(dst);
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2005-04-16 16:20:36 -06:00
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/* Initialize sk->sk_rcv_saddr, if the transport is the
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* association's active path for getsockname().
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*/
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if (asoc && (transport == asoc->peer.active_path))
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2006-11-20 18:13:58 -07:00
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opt->pf->af->to_sk_saddr(&transport->saddr,
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2005-12-02 21:32:29 -07:00
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asoc->base.sk);
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2005-04-16 16:20:36 -06:00
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} else
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2005-12-22 12:36:46 -07:00
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transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
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2005-04-16 16:20:36 -06:00
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}
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/* Hold a reference to a transport. */
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void sctp_transport_hold(struct sctp_transport *transport)
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{
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atomic_inc(&transport->refcnt);
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}
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/* Release a reference to a transport and clean up
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* if there are no more references.
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*/
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void sctp_transport_put(struct sctp_transport *transport)
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{
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if (atomic_dec_and_test(&transport->refcnt))
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sctp_transport_destroy(transport);
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}
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/* Update transport's RTO based on the newly calculated RTT. */
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void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
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{
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/* Check for valid transport. */
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SCTP_ASSERT(tp, "NULL transport", return);
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/* We should not be doing any RTO updates unless rto_pending is set. */
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SCTP_ASSERT(tp->rto_pending, "rto_pending not set", return);
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if (tp->rttvar || tp->srtt) {
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/* 6.3.1 C3) When a new RTT measurement R' is made, set
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* RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'|
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* SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R'
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*/
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/* Note: The above algorithm has been rewritten to
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* express rto_beta and rto_alpha as inverse powers
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* of two.
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* For example, assuming the default value of RTO.Alpha of
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* 1/8, rto_alpha would be expressed as 3.
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*/
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tp->rttvar = tp->rttvar - (tp->rttvar >> sctp_rto_beta)
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+ ((abs(tp->srtt - rtt)) >> sctp_rto_beta);
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tp->srtt = tp->srtt - (tp->srtt >> sctp_rto_alpha)
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+ (rtt >> sctp_rto_alpha);
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} else {
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/* 6.3.1 C2) When the first RTT measurement R is made, set
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* SRTT <- R, RTTVAR <- R/2.
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*/
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tp->srtt = rtt;
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tp->rttvar = rtt >> 1;
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}
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/* 6.3.1 G1) Whenever RTTVAR is computed, if RTTVAR = 0, then
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* adjust RTTVAR <- G, where G is the CLOCK GRANULARITY.
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*/
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if (tp->rttvar == 0)
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tp->rttvar = SCTP_CLOCK_GRANULARITY;
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|
|
|
/* 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;
|
|
|
|
|
|
|
|
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;
|
|
|
|
|
|
|
|
SCTP_DEBUG_PRINTK("%s: transport: %p, rtt: %d, srtt: %d "
|
2006-01-17 12:55:17 -07:00
|
|
|
"rttvar: %d, rto: %ld\n", __FUNCTION__,
|
2005-04-16 16:20:36 -06:00
|
|
|
tp, rtt, tp->srtt, tp->rttvar, tp->rto);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* 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)
|
|
|
|
{
|
|
|
|
__u32 cwnd, ssthresh, flight_size, pba, pmtu;
|
|
|
|
|
|
|
|
cwnd = transport->cwnd;
|
|
|
|
flight_size = transport->flight_size;
|
|
|
|
|
|
|
|
/* The appropriate cwnd increase algorithm is performed if, and only
|
|
|
|
* if the cumulative TSN has advanced and the congestion window is
|
|
|
|
* being fully utilized.
|
|
|
|
*/
|
|
|
|
if ((transport->asoc->ctsn_ack_point >= sack_ctsn) ||
|
|
|
|
(flight_size < cwnd))
|
|
|
|
return;
|
|
|
|
|
|
|
|
ssthresh = transport->ssthresh;
|
|
|
|
pba = transport->partial_bytes_acked;
|
2005-12-22 12:36:46 -07:00
|
|
|
pmtu = transport->asoc->pathmtu;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
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.
|
|
|
|
*/
|
|
|
|
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);
|
|
|
|
} else {
|
|
|
|
/* RFC 2960 7.2.2 Whenever cwnd is greater than ssthresh,
|
|
|
|
* upon each SACK arrival that advances the Cumulative TSN Ack
|
|
|
|
* Point, 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.
|
|
|
|
*
|
|
|
|
* 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),
|
|
|
|
* increase cwnd by MTU, and reset partial_bytes_acked to
|
|
|
|
* (partial_bytes_acked - cwnd).
|
|
|
|
*/
|
|
|
|
pba += bytes_acked;
|
|
|
|
if (pba >= cwnd) {
|
|
|
|
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);
|
|
|
|
}
|
|
|
|
|
|
|
|
transport->cwnd = cwnd;
|
|
|
|
transport->partial_bytes_acked = pba;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This routine is used to lower the transport's cwnd when congestion is
|
|
|
|
* detected.
|
|
|
|
*/
|
|
|
|
void sctp_transport_lower_cwnd(struct sctp_transport *transport,
|
|
|
|
sctp_lower_cwnd_t reason)
|
|
|
|
{
|
|
|
|
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,
|
2005-12-22 12:36:46 -07:00
|
|
|
4*transport->asoc->pathmtu);
|
|
|
|
transport->cwnd = transport->asoc->pathmtu;
|
2005-04-16 16:20:36 -06:00
|
|
|
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
|
|
|
|
*/
|
|
|
|
transport->ssthresh = max(transport->cwnd/2,
|
2005-12-22 12:36:46 -07:00
|
|
|
4*transport->asoc->pathmtu);
|
2005-04-16 16:20:36 -06:00
|
|
|
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 ((jiffies - transport->last_time_ecne_reduced) >
|
|
|
|
transport->rtt) {
|
|
|
|
transport->ssthresh = max(transport->cwnd/2,
|
2005-12-22 12:36:46 -07:00
|
|
|
4*transport->asoc->pathmtu);
|
2005-04-16 16:20:36 -06:00
|
|
|
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.
|
|
|
|
*/
|
|
|
|
if ((jiffies - transport->last_time_used) > transport->rto)
|
|
|
|
transport->cwnd = max(transport->cwnd/2,
|
2005-12-22 12:36:46 -07:00
|
|
|
4*transport->asoc->pathmtu);
|
2005-04-16 16:20:36 -06:00
|
|
|
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);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* What is the next timeout value for this transport? */
|
|
|
|
unsigned long sctp_transport_timeout(struct sctp_transport *t)
|
|
|
|
{
|
|
|
|
unsigned long timeout;
|
2006-07-21 15:48:50 -06:00
|
|
|
timeout = t->rto + sctp_jitter(t->rto);
|
|
|
|
if (t->state != SCTP_UNCONFIRMED)
|
|
|
|
timeout += t->hbinterval;
|
2005-04-16 16:20:36 -06:00
|
|
|
timeout += jiffies;
|
|
|
|
return timeout;
|
|
|
|
}
|