Vlad Yasevich | 60c778b | 2008-01-11 09:57:09 -0500 | [diff] [blame] | 1 | /* SCTP kernel implementation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (c) 1999-2000 Cisco, Inc. |
| 3 | * Copyright (c) 1999-2001 Motorola, Inc. |
| 4 | * Copyright (c) 2001-2003 International Business Machines Corp. |
| 5 | * Copyright (c) 2001 Intel Corp. |
| 6 | * Copyright (c) 2001 La Monte H.P. Yarroll |
| 7 | * |
Vlad Yasevich | 60c778b | 2008-01-11 09:57:09 -0500 | [diff] [blame] | 8 | * This file is part of the SCTP kernel implementation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | * |
| 10 | * This module provides the abstraction for an SCTP tranport representing |
| 11 | * a remote transport address. For local transport addresses, we just use |
| 12 | * union sctp_addr. |
| 13 | * |
Vlad Yasevich | 60c778b | 2008-01-11 09:57:09 -0500 | [diff] [blame] | 14 | * This SCTP implementation is free software; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | * you can redistribute it and/or modify it under the terms of |
| 16 | * the GNU General Public License as published by |
| 17 | * the Free Software Foundation; either version 2, or (at your option) |
| 18 | * any later version. |
| 19 | * |
Vlad Yasevich | 60c778b | 2008-01-11 09:57:09 -0500 | [diff] [blame] | 20 | * This SCTP implementation is distributed in the hope that it |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| 22 | * ************************ |
| 23 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| 24 | * See the GNU General Public License for more details. |
| 25 | * |
| 26 | * You should have received a copy of the GNU General Public License |
| 27 | * along with GNU CC; see the file COPYING. If not, write to |
| 28 | * the Free Software Foundation, 59 Temple Place - Suite 330, |
| 29 | * Boston, MA 02111-1307, USA. |
| 30 | * |
| 31 | * Please send any bug reports or fixes you make to the |
| 32 | * email address(es): |
| 33 | * lksctp developers <lksctp-developers@lists.sourceforge.net> |
| 34 | * |
| 35 | * Or submit a bug report through the following website: |
| 36 | * http://www.sf.net/projects/lksctp |
| 37 | * |
| 38 | * Written or modified by: |
| 39 | * La Monte H.P. Yarroll <piggy@acm.org> |
| 40 | * Karl Knutson <karl@athena.chicago.il.us> |
| 41 | * Jon Grimm <jgrimm@us.ibm.com> |
| 42 | * Xingang Guo <xingang.guo@intel.com> |
| 43 | * Hui Huang <hui.huang@nokia.com> |
| 44 | * Sridhar Samudrala <sri@us.ibm.com> |
| 45 | * Ardelle Fan <ardelle.fan@intel.com> |
| 46 | * |
| 47 | * Any bugs reported given to us we will try to fix... any fixes shared will |
| 48 | * be incorporated into the next SCTP release. |
| 49 | */ |
| 50 | |
Joe Perches | 145ce50 | 2010-08-24 13:21:08 +0000 | [diff] [blame] | 51 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 52 | |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 53 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | #include <linux/types.h> |
Sridhar Samudrala | ad8fec1 | 2006-07-21 14:48:50 -0700 | [diff] [blame] | 55 | #include <linux/random.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | #include <net/sctp/sctp.h> |
| 57 | #include <net/sctp/sm.h> |
| 58 | |
| 59 | /* 1st Level Abstractions. */ |
| 60 | |
| 61 | /* Initialize a new transport from provided memory. */ |
| 62 | static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer, |
| 63 | const union sctp_addr *addr, |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 64 | gfp_t gfp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | { |
| 66 | /* Copy in the address. */ |
| 67 | peer->ipaddr = *addr; |
| 68 | peer->af_specific = sctp_get_af_specific(addr->sa.sa_family); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | memset(&peer->saddr, 0, sizeof(union sctp_addr)); |
| 70 | |
| 71 | /* From 6.3.1 RTO Calculation: |
| 72 | * |
| 73 | * C1) Until an RTT measurement has been made for a packet sent to the |
| 74 | * given destination transport address, set RTO to the protocol |
| 75 | * parameter 'RTO.Initial'. |
| 76 | */ |
Andrei Pelinescu-Onciul | 5fdd4ba | 2009-11-29 00:14:02 -0800 | [diff] [blame] | 77 | peer->rto = msecs_to_jiffies(sctp_rto_initial); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
| 79 | peer->last_time_heard = jiffies; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | peer->last_time_ecne_reduced = jiffies; |
| 81 | |
Frank Filz | 52ccb8e | 2005-12-22 11:36:46 -0800 | [diff] [blame] | 82 | peer->param_flags = SPP_HB_DISABLE | |
| 83 | SPP_PMTUD_ENABLE | |
| 84 | SPP_SACKDELAY_ENABLE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | |
| 86 | /* Initialize the default path max_retrans. */ |
Frank Filz | 52ccb8e | 2005-12-22 11:36:46 -0800 | [diff] [blame] | 87 | peer->pathmaxrxt = sctp_max_retrans_path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | |
| 89 | INIT_LIST_HEAD(&peer->transmitted); |
| 90 | INIT_LIST_HEAD(&peer->send_ready); |
| 91 | INIT_LIST_HEAD(&peer->transports); |
| 92 | |
Pavel Emelyanov | b24b8a2 | 2008-01-23 21:20:07 -0800 | [diff] [blame] | 93 | setup_timer(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event, |
| 94 | (unsigned long)peer); |
| 95 | setup_timer(&peer->hb_timer, sctp_generate_heartbeat_event, |
| 96 | (unsigned long)peer); |
Vlad Yasevich | 50b5d6a | 2010-05-06 00:56:07 -0700 | [diff] [blame] | 97 | setup_timer(&peer->proto_unreach_timer, |
| 98 | sctp_generate_proto_unreach_event, (unsigned long)peer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
Sridhar Samudrala | ad8fec1 | 2006-07-21 14:48:50 -0700 | [diff] [blame] | 100 | /* Initialize the 64-bit random nonce sent with heartbeat. */ |
| 101 | get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce)); |
| 102 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | atomic_set(&peer->refcnt, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | |
| 105 | return peer; |
| 106 | } |
| 107 | |
| 108 | /* Allocate and initialize a new transport. */ |
Alexey Dobriyan | 3182cd8 | 2005-07-11 20:57:47 -0700 | [diff] [blame] | 109 | struct sctp_transport *sctp_transport_new(const union sctp_addr *addr, |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 110 | gfp_t gfp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | { |
YOSHIFUJI Hideaki | d808ad9 | 2007-02-09 23:25:18 +0900 | [diff] [blame] | 112 | struct sctp_transport *transport; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | |
YOSHIFUJI Hideaki | d808ad9 | 2007-02-09 23:25:18 +0900 | [diff] [blame] | 114 | transport = t_new(struct sctp_transport, gfp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | if (!transport) |
| 116 | goto fail; |
| 117 | |
| 118 | if (!sctp_transport_init(transport, addr, gfp)) |
| 119 | goto fail_init; |
| 120 | |
| 121 | transport->malloced = 1; |
| 122 | SCTP_DBG_OBJCNT_INC(transport); |
| 123 | |
| 124 | return transport; |
| 125 | |
| 126 | fail_init: |
| 127 | kfree(transport); |
| 128 | |
| 129 | fail: |
| 130 | return NULL; |
| 131 | } |
| 132 | |
| 133 | /* This transport is no longer needed. Free up if possible, or |
| 134 | * delay until it last reference count. |
| 135 | */ |
| 136 | void sctp_transport_free(struct sctp_transport *transport) |
| 137 | { |
| 138 | transport->dead = 1; |
| 139 | |
| 140 | /* Try to delete the heartbeat timer. */ |
| 141 | if (del_timer(&transport->hb_timer)) |
| 142 | sctp_transport_put(transport); |
| 143 | |
| 144 | /* Delete the T3_rtx timer if it's active. |
| 145 | * There is no point in not doing this now and letting |
| 146 | * structure hang around in memory since we know |
| 147 | * the tranport is going away. |
| 148 | */ |
| 149 | if (timer_pending(&transport->T3_rtx_timer) && |
| 150 | del_timer(&transport->T3_rtx_timer)) |
| 151 | sctp_transport_put(transport); |
| 152 | |
Wei Yongjun | 55fa0cf | 2010-05-09 16:56:07 +0000 | [diff] [blame] | 153 | /* Delete the ICMP proto unreachable timer if it's active. */ |
| 154 | if (timer_pending(&transport->proto_unreach_timer) && |
| 155 | del_timer(&transport->proto_unreach_timer)) |
| 156 | sctp_association_put(transport->asoc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | |
| 158 | sctp_transport_put(transport); |
| 159 | } |
| 160 | |
| 161 | /* Destroy the transport data structure. |
| 162 | * Assumes there are no more users of this structure. |
| 163 | */ |
| 164 | static void sctp_transport_destroy(struct sctp_transport *transport) |
| 165 | { |
| 166 | SCTP_ASSERT(transport->dead, "Transport is not dead", return); |
| 167 | |
| 168 | if (transport->asoc) |
| 169 | sctp_association_put(transport->asoc); |
| 170 | |
YOSHIFUJI Hideaki | d808ad9 | 2007-02-09 23:25:18 +0900 | [diff] [blame] | 171 | sctp_packet_free(&transport->packet); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
| 173 | dst_release(transport->dst); |
| 174 | kfree(transport); |
| 175 | SCTP_DBG_OBJCNT_DEC(transport); |
| 176 | } |
| 177 | |
| 178 | /* Start T3_rtx timer if it is not already running and update the heartbeat |
| 179 | * timer. This routine is called every time a DATA chunk is sent. |
| 180 | */ |
Vlad Yasevich | d9efc22 | 2010-04-30 22:41:09 -0400 | [diff] [blame] | 181 | void sctp_transport_reset_timers(struct sctp_transport *transport) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | { |
| 183 | /* RFC 2960 6.3.2 Retransmission Timer Rules |
| 184 | * |
| 185 | * R1) Every time a DATA chunk is sent to any address(including a |
| 186 | * retransmission), if the T3-rtx timer of that address is not running |
| 187 | * start it running so that it will expire after the RTO of that |
| 188 | * address. |
| 189 | */ |
| 190 | |
Vlad Yasevich | d9efc22 | 2010-04-30 22:41:09 -0400 | [diff] [blame] | 191 | if (!timer_pending(&transport->T3_rtx_timer)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | if (!mod_timer(&transport->T3_rtx_timer, |
| 193 | jiffies + transport->rto)) |
| 194 | sctp_transport_hold(transport); |
| 195 | |
| 196 | /* When a data chunk is sent, reset the heartbeat interval. */ |
| 197 | if (!mod_timer(&transport->hb_timer, |
| 198 | sctp_transport_timeout(transport))) |
| 199 | sctp_transport_hold(transport); |
| 200 | } |
| 201 | |
| 202 | /* This transport has been assigned to an association. |
| 203 | * Initialize fields from the association or from the sock itself. |
| 204 | * Register the reference count in the association. |
| 205 | */ |
| 206 | void sctp_transport_set_owner(struct sctp_transport *transport, |
| 207 | struct sctp_association *asoc) |
| 208 | { |
| 209 | transport->asoc = asoc; |
| 210 | sctp_association_hold(asoc); |
| 211 | } |
| 212 | |
| 213 | /* Initialize the pmtu of a transport. */ |
Vlad Yasevich | 9914ae3 | 2011-04-26 21:51:31 +0000 | [diff] [blame] | 214 | void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | { |
Vlad Yasevich | da0420b | 2011-04-26 21:54:17 +0000 | [diff] [blame] | 216 | /* If we don't have a fresh route, look one up */ |
| 217 | if (!transport->dst || transport->dst->obsolete > 1) { |
| 218 | dst_release(transport->dst); |
| 219 | transport->af_specific->get_dst(transport, &transport->saddr, |
David S. Miller | 8663c93 | 2011-05-06 16:32:47 -0700 | [diff] [blame] | 220 | &transport->fl, sk); |
Vlad Yasevich | da0420b | 2011-04-26 21:54:17 +0000 | [diff] [blame] | 221 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | |
Vlad Yasevich | da0420b | 2011-04-26 21:54:17 +0000 | [diff] [blame] | 223 | if (transport->dst) { |
| 224 | transport->pathmtu = dst_mtu(transport->dst); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | } else |
Frank Filz | 52ccb8e | 2005-12-22 11:36:46 -0800 | [diff] [blame] | 226 | transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | } |
| 228 | |
Vlad Yasevich | c910b47 | 2007-06-07 13:47:03 -0400 | [diff] [blame] | 229 | /* this is a complete rip-off from __sk_dst_check |
| 230 | * the cookie is always 0 since this is how it's used in the |
| 231 | * pmtu code |
| 232 | */ |
| 233 | static struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t) |
| 234 | { |
| 235 | struct dst_entry *dst = t->dst; |
| 236 | |
| 237 | if (dst && dst->obsolete && dst->ops->check(dst, 0) == NULL) { |
| 238 | dst_release(t->dst); |
| 239 | t->dst = NULL; |
| 240 | return NULL; |
| 241 | } |
| 242 | |
| 243 | return dst; |
| 244 | } |
| 245 | |
| 246 | void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu) |
| 247 | { |
| 248 | struct dst_entry *dst; |
| 249 | |
| 250 | if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { |
Joe Perches | 145ce50 | 2010-08-24 13:21:08 +0000 | [diff] [blame] | 251 | pr_warn("%s: Reported pmtu %d too low, using default minimum of %d\n", |
| 252 | __func__, pmtu, |
| 253 | SCTP_DEFAULT_MINSEGMENT); |
Vlad Yasevich | c910b47 | 2007-06-07 13:47:03 -0400 | [diff] [blame] | 254 | /* Use default minimum segment size and disable |
| 255 | * pmtu discovery on this transport. |
| 256 | */ |
| 257 | t->pathmtu = SCTP_DEFAULT_MINSEGMENT; |
Vlad Yasevich | c910b47 | 2007-06-07 13:47:03 -0400 | [diff] [blame] | 258 | } else { |
| 259 | t->pathmtu = pmtu; |
| 260 | } |
| 261 | |
| 262 | dst = sctp_transport_dst_check(t); |
| 263 | if (dst) |
| 264 | dst->ops->update_pmtu(dst, pmtu); |
| 265 | } |
| 266 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | /* Caches the dst entry and source address for a transport's destination |
| 268 | * address. |
| 269 | */ |
| 270 | void sctp_transport_route(struct sctp_transport *transport, |
| 271 | union sctp_addr *saddr, struct sctp_sock *opt) |
| 272 | { |
| 273 | struct sctp_association *asoc = transport->asoc; |
| 274 | struct sctp_af *af = transport->af_specific; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | |
David S. Miller | 8663c93 | 2011-05-06 16:32:47 -0700 | [diff] [blame] | 276 | af->get_dst(transport, saddr, &transport->fl, sctp_opt2sk(opt)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | |
| 278 | if (saddr) |
| 279 | memcpy(&transport->saddr, saddr, sizeof(union sctp_addr)); |
| 280 | else |
David S. Miller | 8663c93 | 2011-05-06 16:32:47 -0700 | [diff] [blame] | 281 | af->get_saddr(opt, transport, &transport->fl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | |
Frank Filz | 52ccb8e | 2005-12-22 11:36:46 -0800 | [diff] [blame] | 283 | if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) { |
| 284 | return; |
| 285 | } |
Vlad Yasevich | da0420b | 2011-04-26 21:54:17 +0000 | [diff] [blame] | 286 | if (transport->dst) { |
| 287 | transport->pathmtu = dst_mtu(transport->dst); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | |
| 289 | /* Initialize sk->sk_rcv_saddr, if the transport is the |
| 290 | * association's active path for getsockname(). |
YOSHIFUJI Hideaki | d808ad9 | 2007-02-09 23:25:18 +0900 | [diff] [blame] | 291 | */ |
Vlad Yasevich | a78102e | 2009-11-11 11:54:37 +0000 | [diff] [blame] | 292 | if (asoc && (!asoc->peer.primary_path || |
| 293 | (transport == asoc->peer.active_path))) |
Neil Horman | bf031ff | 2005-12-02 20:32:29 -0800 | [diff] [blame] | 294 | opt->pf->af->to_sk_saddr(&transport->saddr, |
| 295 | asoc->base.sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | } else |
Frank Filz | 52ccb8e | 2005-12-22 11:36:46 -0800 | [diff] [blame] | 297 | transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | } |
| 299 | |
| 300 | /* Hold a reference to a transport. */ |
| 301 | void sctp_transport_hold(struct sctp_transport *transport) |
| 302 | { |
| 303 | atomic_inc(&transport->refcnt); |
| 304 | } |
| 305 | |
| 306 | /* Release a reference to a transport and clean up |
| 307 | * if there are no more references. |
| 308 | */ |
| 309 | void sctp_transport_put(struct sctp_transport *transport) |
| 310 | { |
| 311 | if (atomic_dec_and_test(&transport->refcnt)) |
| 312 | sctp_transport_destroy(transport); |
| 313 | } |
| 314 | |
| 315 | /* Update transport's RTO based on the newly calculated RTT. */ |
| 316 | void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt) |
| 317 | { |
| 318 | /* Check for valid transport. */ |
| 319 | SCTP_ASSERT(tp, "NULL transport", return); |
| 320 | |
| 321 | /* We should not be doing any RTO updates unless rto_pending is set. */ |
| 322 | SCTP_ASSERT(tp->rto_pending, "rto_pending not set", return); |
| 323 | |
| 324 | if (tp->rttvar || tp->srtt) { |
| 325 | /* 6.3.1 C3) When a new RTT measurement R' is made, set |
| 326 | * RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'| |
| 327 | * SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R' |
| 328 | */ |
| 329 | |
| 330 | /* Note: The above algorithm has been rewritten to |
| 331 | * express rto_beta and rto_alpha as inverse powers |
| 332 | * of two. |
| 333 | * For example, assuming the default value of RTO.Alpha of |
| 334 | * 1/8, rto_alpha would be expressed as 3. |
| 335 | */ |
| 336 | tp->rttvar = tp->rttvar - (tp->rttvar >> sctp_rto_beta) |
| 337 | + ((abs(tp->srtt - rtt)) >> sctp_rto_beta); |
| 338 | tp->srtt = tp->srtt - (tp->srtt >> sctp_rto_alpha) |
| 339 | + (rtt >> sctp_rto_alpha); |
| 340 | } else { |
| 341 | /* 6.3.1 C2) When the first RTT measurement R is made, set |
| 342 | * SRTT <- R, RTTVAR <- R/2. |
| 343 | */ |
| 344 | tp->srtt = rtt; |
| 345 | tp->rttvar = rtt >> 1; |
| 346 | } |
| 347 | |
| 348 | /* 6.3.1 G1) Whenever RTTVAR is computed, if RTTVAR = 0, then |
| 349 | * adjust RTTVAR <- G, where G is the CLOCK GRANULARITY. |
| 350 | */ |
| 351 | if (tp->rttvar == 0) |
| 352 | tp->rttvar = SCTP_CLOCK_GRANULARITY; |
| 353 | |
| 354 | /* 6.3.1 C3) After the computation, update RTO <- SRTT + 4 * RTTVAR. */ |
| 355 | tp->rto = tp->srtt + (tp->rttvar << 2); |
| 356 | |
| 357 | /* 6.3.1 C6) Whenever RTO is computed, if it is less than RTO.Min |
| 358 | * seconds then it is rounded up to RTO.Min seconds. |
| 359 | */ |
| 360 | if (tp->rto < tp->asoc->rto_min) |
| 361 | tp->rto = tp->asoc->rto_min; |
| 362 | |
| 363 | /* 6.3.1 C7) A maximum value may be placed on RTO provided it is |
| 364 | * at least RTO.max seconds. |
| 365 | */ |
| 366 | if (tp->rto > tp->asoc->rto_max) |
| 367 | tp->rto = tp->asoc->rto_max; |
| 368 | |
| 369 | tp->rtt = rtt; |
| 370 | |
| 371 | /* Reset rto_pending so that a new RTT measurement is started when a |
| 372 | * new data chunk is sent. |
| 373 | */ |
| 374 | tp->rto_pending = 0; |
| 375 | |
| 376 | SCTP_DEBUG_PRINTK("%s: transport: %p, rtt: %d, srtt: %d " |
Harvey Harrison | 0dc4787 | 2008-03-05 20:47:47 -0800 | [diff] [blame] | 377 | "rttvar: %d, rto: %ld\n", __func__, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 378 | tp, rtt, tp->srtt, tp->rttvar, tp->rto); |
| 379 | } |
| 380 | |
| 381 | /* This routine updates the transport's cwnd and partial_bytes_acked |
| 382 | * parameters based on the bytes acked in the received SACK. |
| 383 | */ |
| 384 | void sctp_transport_raise_cwnd(struct sctp_transport *transport, |
| 385 | __u32 sack_ctsn, __u32 bytes_acked) |
| 386 | { |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 387 | struct sctp_association *asoc = transport->asoc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | __u32 cwnd, ssthresh, flight_size, pba, pmtu; |
| 389 | |
| 390 | cwnd = transport->cwnd; |
| 391 | flight_size = transport->flight_size; |
| 392 | |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 393 | /* See if we need to exit Fast Recovery first */ |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 394 | if (asoc->fast_recovery && |
| 395 | TSN_lte(asoc->fast_recovery_exit, sack_ctsn)) |
| 396 | asoc->fast_recovery = 0; |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 397 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | /* The appropriate cwnd increase algorithm is performed if, and only |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 399 | * if the cumulative TSN whould advanced and the congestion window is |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | * being fully utilized. |
| 401 | */ |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 402 | if (TSN_lte(sack_ctsn, transport->asoc->ctsn_ack_point) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | (flight_size < cwnd)) |
| 404 | return; |
| 405 | |
| 406 | ssthresh = transport->ssthresh; |
| 407 | pba = transport->partial_bytes_acked; |
Frank Filz | 52ccb8e | 2005-12-22 11:36:46 -0800 | [diff] [blame] | 408 | pmtu = transport->asoc->pathmtu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | |
| 410 | if (cwnd <= ssthresh) { |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 411 | /* RFC 4960 7.2.1 |
| 412 | * o When cwnd is less than or equal to ssthresh, an SCTP |
| 413 | * endpoint MUST use the slow-start algorithm to increase |
| 414 | * cwnd only if the current congestion window is being fully |
| 415 | * utilized, an incoming SACK advances the Cumulative TSN |
| 416 | * Ack Point, and the data sender is not in Fast Recovery. |
| 417 | * Only when these three conditions are met can the cwnd be |
| 418 | * increased; otherwise, the cwnd MUST not be increased. |
| 419 | * If these conditions are met, then cwnd MUST be increased |
| 420 | * by, at most, the lesser of 1) the total size of the |
| 421 | * previously outstanding DATA chunk(s) acknowledged, and |
| 422 | * 2) the destination's path MTU. This upper bound protects |
| 423 | * against the ACK-Splitting attack outlined in [SAVAGE99]. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | */ |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 425 | if (asoc->fast_recovery) |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 426 | return; |
| 427 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | if (bytes_acked > pmtu) |
| 429 | cwnd += pmtu; |
| 430 | else |
| 431 | cwnd += bytes_acked; |
| 432 | SCTP_DEBUG_PRINTK("%s: SLOW START: transport: %p, " |
| 433 | "bytes_acked: %d, cwnd: %d, ssthresh: %d, " |
| 434 | "flight_size: %d, pba: %d\n", |
Harvey Harrison | 0dc4787 | 2008-03-05 20:47:47 -0800 | [diff] [blame] | 435 | __func__, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | transport, bytes_acked, cwnd, |
| 437 | ssthresh, flight_size, pba); |
| 438 | } else { |
| 439 | /* RFC 2960 7.2.2 Whenever cwnd is greater than ssthresh, |
| 440 | * upon each SACK arrival that advances the Cumulative TSN Ack |
| 441 | * Point, increase partial_bytes_acked by the total number of |
| 442 | * bytes of all new chunks acknowledged in that SACK including |
| 443 | * chunks acknowledged by the new Cumulative TSN Ack and by |
| 444 | * Gap Ack Blocks. |
| 445 | * |
| 446 | * When partial_bytes_acked is equal to or greater than cwnd |
| 447 | * and before the arrival of the SACK the sender had cwnd or |
| 448 | * more bytes of data outstanding (i.e., before arrival of the |
| 449 | * SACK, flightsize was greater than or equal to cwnd), |
| 450 | * increase cwnd by MTU, and reset partial_bytes_acked to |
| 451 | * (partial_bytes_acked - cwnd). |
| 452 | */ |
| 453 | pba += bytes_acked; |
| 454 | if (pba >= cwnd) { |
| 455 | cwnd += pmtu; |
| 456 | pba = ((cwnd < pba) ? (pba - cwnd) : 0); |
| 457 | } |
| 458 | SCTP_DEBUG_PRINTK("%s: CONGESTION AVOIDANCE: " |
| 459 | "transport: %p, bytes_acked: %d, cwnd: %d, " |
| 460 | "ssthresh: %d, flight_size: %d, pba: %d\n", |
Harvey Harrison | 0dc4787 | 2008-03-05 20:47:47 -0800 | [diff] [blame] | 461 | __func__, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | transport, bytes_acked, cwnd, |
| 463 | ssthresh, flight_size, pba); |
| 464 | } |
| 465 | |
| 466 | transport->cwnd = cwnd; |
| 467 | transport->partial_bytes_acked = pba; |
| 468 | } |
| 469 | |
| 470 | /* This routine is used to lower the transport's cwnd when congestion is |
| 471 | * detected. |
| 472 | */ |
| 473 | void sctp_transport_lower_cwnd(struct sctp_transport *transport, |
| 474 | sctp_lower_cwnd_t reason) |
| 475 | { |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 476 | struct sctp_association *asoc = transport->asoc; |
| 477 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | switch (reason) { |
| 479 | case SCTP_LOWER_CWND_T3_RTX: |
| 480 | /* RFC 2960 Section 7.2.3, sctpimpguide |
| 481 | * When the T3-rtx timer expires on an address, SCTP should |
| 482 | * perform slow start by: |
| 483 | * ssthresh = max(cwnd/2, 4*MTU) |
| 484 | * cwnd = 1*MTU |
| 485 | * partial_bytes_acked = 0 |
| 486 | */ |
| 487 | transport->ssthresh = max(transport->cwnd/2, |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 488 | 4*asoc->pathmtu); |
| 489 | transport->cwnd = asoc->pathmtu; |
Vlad Yasevich | 33ce828 | 2009-09-04 18:20:58 -0400 | [diff] [blame] | 490 | |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 491 | /* T3-rtx also clears fast recovery */ |
| 492 | asoc->fast_recovery = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | break; |
| 494 | |
| 495 | case SCTP_LOWER_CWND_FAST_RTX: |
| 496 | /* RFC 2960 7.2.4 Adjust the ssthresh and cwnd of the |
| 497 | * destination address(es) to which the missing DATA chunks |
| 498 | * were last sent, according to the formula described in |
| 499 | * Section 7.2.3. |
YOSHIFUJI Hideaki | d808ad9 | 2007-02-09 23:25:18 +0900 | [diff] [blame] | 500 | * |
| 501 | * RFC 2960 7.2.3, sctpimpguide Upon detection of packet |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | * losses from SACK (see Section 7.2.4), An endpoint |
| 503 | * should do the following: |
| 504 | * ssthresh = max(cwnd/2, 4*MTU) |
| 505 | * cwnd = ssthresh |
| 506 | * partial_bytes_acked = 0 |
| 507 | */ |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 508 | if (asoc->fast_recovery) |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 509 | return; |
| 510 | |
| 511 | /* Mark Fast recovery */ |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 512 | asoc->fast_recovery = 1; |
| 513 | asoc->fast_recovery_exit = asoc->next_tsn - 1; |
Vlad Yasevich | a646523 | 2008-06-04 12:38:43 -0700 | [diff] [blame] | 514 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | transport->ssthresh = max(transport->cwnd/2, |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 516 | 4*asoc->pathmtu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | transport->cwnd = transport->ssthresh; |
| 518 | break; |
| 519 | |
| 520 | case SCTP_LOWER_CWND_ECNE: |
| 521 | /* RFC 2481 Section 6.1.2. |
| 522 | * If the sender receives an ECN-Echo ACK packet |
| 523 | * then the sender knows that congestion was encountered in the |
| 524 | * network on the path from the sender to the receiver. The |
| 525 | * indication of congestion should be treated just as a |
| 526 | * congestion loss in non-ECN Capable TCP. That is, the TCP |
| 527 | * source halves the congestion window "cwnd" and reduces the |
| 528 | * slow start threshold "ssthresh". |
| 529 | * A critical condition is that TCP does not react to |
| 530 | * congestion indications more than once every window of |
| 531 | * data (or more loosely more than once every round-trip time). |
| 532 | */ |
Wei Yongjun | f61f6f8 | 2009-03-02 09:46:13 +0000 | [diff] [blame] | 533 | if (time_after(jiffies, transport->last_time_ecne_reduced + |
| 534 | transport->rtt)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | transport->ssthresh = max(transport->cwnd/2, |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 536 | 4*asoc->pathmtu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | transport->cwnd = transport->ssthresh; |
| 538 | transport->last_time_ecne_reduced = jiffies; |
| 539 | } |
| 540 | break; |
| 541 | |
| 542 | case SCTP_LOWER_CWND_INACTIVE: |
| 543 | /* RFC 2960 Section 7.2.1, sctpimpguide |
| 544 | * When the endpoint does not transmit data on a given |
| 545 | * transport address, the cwnd of the transport address |
| 546 | * should be adjusted to max(cwnd/2, 4*MTU) per RTO. |
| 547 | * NOTE: Although the draft recommends that this check needs |
| 548 | * to be done every RTO interval, we do it every hearbeat |
| 549 | * interval. |
| 550 | */ |
Vlad Yasevich | 245cba7 | 2009-11-23 15:53:58 -0500 | [diff] [blame] | 551 | transport->cwnd = max(transport->cwnd/2, |
Vlad Yasevich | cf9b481 | 2010-04-30 22:41:10 -0400 | [diff] [blame] | 552 | 4*asoc->pathmtu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | break; |
Stephen Hemminger | 3ff50b7 | 2007-04-20 17:09:22 -0700 | [diff] [blame] | 554 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | |
| 556 | transport->partial_bytes_acked = 0; |
| 557 | SCTP_DEBUG_PRINTK("%s: transport: %p reason: %d cwnd: " |
Harvey Harrison | 0dc4787 | 2008-03-05 20:47:47 -0800 | [diff] [blame] | 558 | "%d ssthresh: %d\n", __func__, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | transport, reason, |
| 560 | transport->cwnd, transport->ssthresh); |
| 561 | } |
| 562 | |
Vlad Yasevich | 46d5a80 | 2009-11-23 15:54:00 -0500 | [diff] [blame] | 563 | /* Apply Max.Burst limit to the congestion window: |
| 564 | * sctpimpguide-05 2.14.2 |
| 565 | * D) When the time comes for the sender to |
| 566 | * transmit new DATA chunks, the protocol parameter Max.Burst MUST |
| 567 | * first be applied to limit how many new DATA chunks may be sent. |
| 568 | * The limit is applied by adjusting cwnd as follows: |
| 569 | * if ((flightsize+ Max.Burst * MTU) < cwnd) |
| 570 | * cwnd = flightsize + Max.Burst * MTU |
| 571 | */ |
| 572 | |
| 573 | void sctp_transport_burst_limited(struct sctp_transport *t) |
| 574 | { |
| 575 | struct sctp_association *asoc = t->asoc; |
| 576 | u32 old_cwnd = t->cwnd; |
| 577 | u32 max_burst_bytes; |
| 578 | |
| 579 | if (t->burst_limited) |
| 580 | return; |
| 581 | |
| 582 | max_burst_bytes = t->flight_size + (asoc->max_burst * asoc->pathmtu); |
| 583 | if (max_burst_bytes < old_cwnd) { |
| 584 | t->cwnd = max_burst_bytes; |
| 585 | t->burst_limited = old_cwnd; |
| 586 | } |
| 587 | } |
| 588 | |
| 589 | /* Restore the old cwnd congestion window, after the burst had it's |
| 590 | * desired effect. |
| 591 | */ |
| 592 | void sctp_transport_burst_reset(struct sctp_transport *t) |
| 593 | { |
| 594 | if (t->burst_limited) { |
| 595 | t->cwnd = t->burst_limited; |
| 596 | t->burst_limited = 0; |
| 597 | } |
| 598 | } |
| 599 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | /* What is the next timeout value for this transport? */ |
| 601 | unsigned long sctp_transport_timeout(struct sctp_transport *t) |
| 602 | { |
| 603 | unsigned long timeout; |
Sridhar Samudrala | ad8fec1 | 2006-07-21 14:48:50 -0700 | [diff] [blame] | 604 | timeout = t->rto + sctp_jitter(t->rto); |
| 605 | if (t->state != SCTP_UNCONFIRMED) |
| 606 | timeout += t->hbinterval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | timeout += jiffies; |
| 608 | return timeout; |
| 609 | } |
Vlad Yasevich | 749bf92 | 2007-03-19 17:02:30 -0700 | [diff] [blame] | 610 | |
| 611 | /* Reset transport variables to their initial values */ |
| 612 | void sctp_transport_reset(struct sctp_transport *t) |
| 613 | { |
| 614 | struct sctp_association *asoc = t->asoc; |
| 615 | |
| 616 | /* RFC 2960 (bis), Section 5.2.4 |
| 617 | * All the congestion control parameters (e.g., cwnd, ssthresh) |
| 618 | * related to this peer MUST be reset to their initial values |
| 619 | * (see Section 6.2.1) |
| 620 | */ |
| 621 | t->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380)); |
Vlad Yasevich | 46d5a80 | 2009-11-23 15:54:00 -0500 | [diff] [blame] | 622 | t->burst_limited = 0; |
Vlad Yasevich | 289f424 | 2007-03-22 12:26:25 -0700 | [diff] [blame] | 623 | t->ssthresh = asoc->peer.i.a_rwnd; |
Andrei Pelinescu-Onciul | 5fdd4ba | 2009-11-29 00:14:02 -0800 | [diff] [blame] | 624 | t->rto = asoc->rto_initial; |
Vlad Yasevich | 749bf92 | 2007-03-19 17:02:30 -0700 | [diff] [blame] | 625 | t->rtt = 0; |
| 626 | t->srtt = 0; |
| 627 | t->rttvar = 0; |
| 628 | |
| 629 | /* Reset these additional varibles so that we have a clean |
| 630 | * slate. |
| 631 | */ |
| 632 | t->partial_bytes_acked = 0; |
| 633 | t->flight_size = 0; |
| 634 | t->error_count = 0; |
| 635 | t->rto_pending = 0; |
Vlad Yasevich | faee47c | 2009-02-13 08:33:43 +0000 | [diff] [blame] | 636 | t->hb_sent = 0; |
Vlad Yasevich | 749bf92 | 2007-03-19 17:02:30 -0700 | [diff] [blame] | 637 | |
| 638 | /* Initialize the state information for SFR-CACC */ |
| 639 | t->cacc.changeover_active = 0; |
| 640 | t->cacc.cycling_changeover = 0; |
| 641 | t->cacc.next_tsn_at_change = 0; |
| 642 | t->cacc.cacc_saw_newack = 0; |
| 643 | } |
Michio Honda | ddc4bbe | 2011-06-17 11:03:23 +0900 | [diff] [blame] | 644 | |
| 645 | /* Schedule retransmission on the given transport */ |
| 646 | void sctp_transport_immediate_rtx(struct sctp_transport *t) |
| 647 | { |
| 648 | /* Stop pending T3_rtx_timer */ |
| 649 | if (timer_pending(&t->T3_rtx_timer)) { |
| 650 | (void)del_timer(&t->T3_rtx_timer); |
| 651 | sctp_transport_put(t); |
| 652 | } |
| 653 | sctp_retransmit(&t->asoc->outqueue, t, SCTP_RTXR_T3_RTX); |
| 654 | if (!timer_pending(&t->T3_rtx_timer)) { |
| 655 | if (!mod_timer(&t->T3_rtx_timer, jiffies + t->rto)) |
| 656 | sctp_transport_hold(t); |
| 657 | } |
| 658 | return; |
| 659 | } |