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1da177e4 LT |
1 | /* SCTP kernel reference Implementation |
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 | * | |
8 | * This file is part of the SCTP kernel reference Implementation | |
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 | * | |
14 | * The SCTP reference implementation is free software; | |
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 | * | |
20 | * The SCTP reference implementation is distributed in the hope that it | |
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 | ||
51 | #include <linux/types.h> | |
52 | #include <net/sctp/sctp.h> | |
53 | #include <net/sctp/sm.h> | |
54 | ||
55 | /* 1st Level Abstractions. */ | |
56 | ||
57 | /* Initialize a new transport from provided memory. */ | |
58 | static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer, | |
59 | const union sctp_addr *addr, | |
dd0fc66f | 60 | gfp_t gfp) |
1da177e4 LT |
61 | { |
62 | /* Copy in the address. */ | |
63 | peer->ipaddr = *addr; | |
64 | peer->af_specific = sctp_get_af_specific(addr->sa.sa_family); | |
65 | peer->asoc = NULL; | |
66 | ||
67 | peer->dst = NULL; | |
68 | memset(&peer->saddr, 0, sizeof(union sctp_addr)); | |
69 | ||
70 | /* From 6.3.1 RTO Calculation: | |
71 | * | |
72 | * C1) Until an RTT measurement has been made for a packet sent to the | |
73 | * given destination transport address, set RTO to the protocol | |
74 | * parameter 'RTO.Initial'. | |
75 | */ | |
76 | peer->rtt = 0; | |
77 | peer->rto = sctp_rto_initial; | |
78 | peer->rttvar = 0; | |
79 | peer->srtt = 0; | |
80 | peer->rto_pending = 0; | |
81 | ||
82 | peer->last_time_heard = jiffies; | |
83 | peer->last_time_used = jiffies; | |
84 | peer->last_time_ecne_reduced = jiffies; | |
85 | ||
3f7a87d2 FF |
86 | peer->init_sent_count = 0; |
87 | ||
88 | peer->state = SCTP_ACTIVE; | |
52ccb8e9 FF |
89 | peer->param_flags = SPP_HB_DISABLE | |
90 | SPP_PMTUD_ENABLE | | |
91 | SPP_SACKDELAY_ENABLE; | |
92 | peer->hbinterval = 0; | |
1da177e4 LT |
93 | |
94 | /* Initialize the default path max_retrans. */ | |
52ccb8e9 | 95 | peer->pathmaxrxt = sctp_max_retrans_path; |
1da177e4 LT |
96 | peer->error_count = 0; |
97 | ||
98 | INIT_LIST_HEAD(&peer->transmitted); | |
99 | INIT_LIST_HEAD(&peer->send_ready); | |
100 | INIT_LIST_HEAD(&peer->transports); | |
101 | ||
102 | /* Set up the retransmission timer. */ | |
103 | init_timer(&peer->T3_rtx_timer); | |
104 | peer->T3_rtx_timer.function = sctp_generate_t3_rtx_event; | |
105 | peer->T3_rtx_timer.data = (unsigned long)peer; | |
106 | ||
107 | /* Set up the heartbeat timer. */ | |
108 | init_timer(&peer->hb_timer); | |
1da177e4 LT |
109 | peer->hb_timer.function = sctp_generate_heartbeat_event; |
110 | peer->hb_timer.data = (unsigned long)peer; | |
111 | ||
112 | atomic_set(&peer->refcnt, 1); | |
113 | peer->dead = 0; | |
114 | ||
115 | peer->malloced = 0; | |
116 | ||
117 | /* Initialize the state information for SFR-CACC */ | |
118 | peer->cacc.changeover_active = 0; | |
119 | peer->cacc.cycling_changeover = 0; | |
120 | peer->cacc.next_tsn_at_change = 0; | |
121 | peer->cacc.cacc_saw_newack = 0; | |
122 | ||
123 | return peer; | |
124 | } | |
125 | ||
126 | /* Allocate and initialize a new transport. */ | |
3182cd84 | 127 | struct sctp_transport *sctp_transport_new(const union sctp_addr *addr, |
dd0fc66f | 128 | gfp_t gfp) |
1da177e4 LT |
129 | { |
130 | struct sctp_transport *transport; | |
131 | ||
132 | transport = t_new(struct sctp_transport, gfp); | |
133 | if (!transport) | |
134 | goto fail; | |
135 | ||
136 | if (!sctp_transport_init(transport, addr, gfp)) | |
137 | goto fail_init; | |
138 | ||
139 | transport->malloced = 1; | |
140 | SCTP_DBG_OBJCNT_INC(transport); | |
141 | ||
142 | return transport; | |
143 | ||
144 | fail_init: | |
145 | kfree(transport); | |
146 | ||
147 | fail: | |
148 | return NULL; | |
149 | } | |
150 | ||
151 | /* This transport is no longer needed. Free up if possible, or | |
152 | * delay until it last reference count. | |
153 | */ | |
154 | void sctp_transport_free(struct sctp_transport *transport) | |
155 | { | |
156 | transport->dead = 1; | |
157 | ||
158 | /* Try to delete the heartbeat timer. */ | |
159 | if (del_timer(&transport->hb_timer)) | |
160 | sctp_transport_put(transport); | |
161 | ||
162 | /* Delete the T3_rtx timer if it's active. | |
163 | * There is no point in not doing this now and letting | |
164 | * structure hang around in memory since we know | |
165 | * the tranport is going away. | |
166 | */ | |
167 | if (timer_pending(&transport->T3_rtx_timer) && | |
168 | del_timer(&transport->T3_rtx_timer)) | |
169 | sctp_transport_put(transport); | |
170 | ||
171 | ||
172 | sctp_transport_put(transport); | |
173 | } | |
174 | ||
175 | /* Destroy the transport data structure. | |
176 | * Assumes there are no more users of this structure. | |
177 | */ | |
178 | static void sctp_transport_destroy(struct sctp_transport *transport) | |
179 | { | |
180 | SCTP_ASSERT(transport->dead, "Transport is not dead", return); | |
181 | ||
182 | if (transport->asoc) | |
183 | sctp_association_put(transport->asoc); | |
184 | ||
185 | sctp_packet_free(&transport->packet); | |
186 | ||
187 | dst_release(transport->dst); | |
188 | kfree(transport); | |
189 | SCTP_DBG_OBJCNT_DEC(transport); | |
190 | } | |
191 | ||
192 | /* Start T3_rtx timer if it is not already running and update the heartbeat | |
193 | * timer. This routine is called every time a DATA chunk is sent. | |
194 | */ | |
195 | void sctp_transport_reset_timers(struct sctp_transport *transport) | |
196 | { | |
197 | /* RFC 2960 6.3.2 Retransmission Timer Rules | |
198 | * | |
199 | * R1) Every time a DATA chunk is sent to any address(including a | |
200 | * retransmission), if the T3-rtx timer of that address is not running | |
201 | * start it running so that it will expire after the RTO of that | |
202 | * address. | |
203 | */ | |
204 | ||
205 | if (!timer_pending(&transport->T3_rtx_timer)) | |
206 | if (!mod_timer(&transport->T3_rtx_timer, | |
207 | jiffies + transport->rto)) | |
208 | sctp_transport_hold(transport); | |
209 | ||
210 | /* When a data chunk is sent, reset the heartbeat interval. */ | |
211 | if (!mod_timer(&transport->hb_timer, | |
212 | sctp_transport_timeout(transport))) | |
213 | sctp_transport_hold(transport); | |
214 | } | |
215 | ||
216 | /* This transport has been assigned to an association. | |
217 | * Initialize fields from the association or from the sock itself. | |
218 | * Register the reference count in the association. | |
219 | */ | |
220 | void sctp_transport_set_owner(struct sctp_transport *transport, | |
221 | struct sctp_association *asoc) | |
222 | { | |
223 | transport->asoc = asoc; | |
224 | sctp_association_hold(asoc); | |
225 | } | |
226 | ||
227 | /* Initialize the pmtu of a transport. */ | |
228 | void sctp_transport_pmtu(struct sctp_transport *transport) | |
229 | { | |
230 | struct dst_entry *dst; | |
231 | ||
232 | dst = transport->af_specific->get_dst(NULL, &transport->ipaddr, NULL); | |
233 | ||
234 | if (dst) { | |
52ccb8e9 | 235 | transport->pathmtu = dst_mtu(dst); |
1da177e4 LT |
236 | dst_release(dst); |
237 | } else | |
52ccb8e9 | 238 | transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; |
1da177e4 LT |
239 | } |
240 | ||
241 | /* Caches the dst entry and source address for a transport's destination | |
242 | * address. | |
243 | */ | |
244 | void sctp_transport_route(struct sctp_transport *transport, | |
245 | union sctp_addr *saddr, struct sctp_sock *opt) | |
246 | { | |
247 | struct sctp_association *asoc = transport->asoc; | |
248 | struct sctp_af *af = transport->af_specific; | |
249 | union sctp_addr *daddr = &transport->ipaddr; | |
250 | struct dst_entry *dst; | |
251 | ||
252 | dst = af->get_dst(asoc, daddr, saddr); | |
253 | ||
254 | if (saddr) | |
255 | memcpy(&transport->saddr, saddr, sizeof(union sctp_addr)); | |
256 | else | |
257 | af->get_saddr(asoc, dst, daddr, &transport->saddr); | |
258 | ||
259 | transport->dst = dst; | |
52ccb8e9 FF |
260 | if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) { |
261 | return; | |
262 | } | |
1da177e4 | 263 | if (dst) { |
52ccb8e9 | 264 | transport->pathmtu = dst_mtu(dst); |
1da177e4 LT |
265 | |
266 | /* Initialize sk->sk_rcv_saddr, if the transport is the | |
267 | * association's active path for getsockname(). | |
268 | */ | |
269 | if (asoc && (transport == asoc->peer.active_path)) | |
bf031fff NH |
270 | opt->pf->af->to_sk_saddr(&transport->saddr, |
271 | asoc->base.sk); | |
1da177e4 | 272 | } else |
52ccb8e9 | 273 | transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; |
1da177e4 LT |
274 | } |
275 | ||
276 | /* Hold a reference to a transport. */ | |
277 | void sctp_transport_hold(struct sctp_transport *transport) | |
278 | { | |
279 | atomic_inc(&transport->refcnt); | |
280 | } | |
281 | ||
282 | /* Release a reference to a transport and clean up | |
283 | * if there are no more references. | |
284 | */ | |
285 | void sctp_transport_put(struct sctp_transport *transport) | |
286 | { | |
287 | if (atomic_dec_and_test(&transport->refcnt)) | |
288 | sctp_transport_destroy(transport); | |
289 | } | |
290 | ||
291 | /* Update transport's RTO based on the newly calculated RTT. */ | |
292 | void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt) | |
293 | { | |
294 | /* Check for valid transport. */ | |
295 | SCTP_ASSERT(tp, "NULL transport", return); | |
296 | ||
297 | /* We should not be doing any RTO updates unless rto_pending is set. */ | |
298 | SCTP_ASSERT(tp->rto_pending, "rto_pending not set", return); | |
299 | ||
300 | if (tp->rttvar || tp->srtt) { | |
301 | /* 6.3.1 C3) When a new RTT measurement R' is made, set | |
302 | * RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'| | |
303 | * SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R' | |
304 | */ | |
305 | ||
306 | /* Note: The above algorithm has been rewritten to | |
307 | * express rto_beta and rto_alpha as inverse powers | |
308 | * of two. | |
309 | * For example, assuming the default value of RTO.Alpha of | |
310 | * 1/8, rto_alpha would be expressed as 3. | |
311 | */ | |
312 | tp->rttvar = tp->rttvar - (tp->rttvar >> sctp_rto_beta) | |
313 | + ((abs(tp->srtt - rtt)) >> sctp_rto_beta); | |
314 | tp->srtt = tp->srtt - (tp->srtt >> sctp_rto_alpha) | |
315 | + (rtt >> sctp_rto_alpha); | |
316 | } else { | |
317 | /* 6.3.1 C2) When the first RTT measurement R is made, set | |
318 | * SRTT <- R, RTTVAR <- R/2. | |
319 | */ | |
320 | tp->srtt = rtt; | |
321 | tp->rttvar = rtt >> 1; | |
322 | } | |
323 | ||
324 | /* 6.3.1 G1) Whenever RTTVAR is computed, if RTTVAR = 0, then | |
325 | * adjust RTTVAR <- G, where G is the CLOCK GRANULARITY. | |
326 | */ | |
327 | if (tp->rttvar == 0) | |
328 | tp->rttvar = SCTP_CLOCK_GRANULARITY; | |
329 | ||
330 | /* 6.3.1 C3) After the computation, update RTO <- SRTT + 4 * RTTVAR. */ | |
331 | tp->rto = tp->srtt + (tp->rttvar << 2); | |
332 | ||
333 | /* 6.3.1 C6) Whenever RTO is computed, if it is less than RTO.Min | |
334 | * seconds then it is rounded up to RTO.Min seconds. | |
335 | */ | |
336 | if (tp->rto < tp->asoc->rto_min) | |
337 | tp->rto = tp->asoc->rto_min; | |
338 | ||
339 | /* 6.3.1 C7) A maximum value may be placed on RTO provided it is | |
340 | * at least RTO.max seconds. | |
341 | */ | |
342 | if (tp->rto > tp->asoc->rto_max) | |
343 | tp->rto = tp->asoc->rto_max; | |
344 | ||
345 | tp->rtt = rtt; | |
346 | ||
347 | /* Reset rto_pending so that a new RTT measurement is started when a | |
348 | * new data chunk is sent. | |
349 | */ | |
350 | tp->rto_pending = 0; | |
351 | ||
352 | SCTP_DEBUG_PRINTK("%s: transport: %p, rtt: %d, srtt: %d " | |
8116ffad | 353 | "rttvar: %d, rto: %ld\n", __FUNCTION__, |
1da177e4 LT |
354 | tp, rtt, tp->srtt, tp->rttvar, tp->rto); |
355 | } | |
356 | ||
357 | /* This routine updates the transport's cwnd and partial_bytes_acked | |
358 | * parameters based on the bytes acked in the received SACK. | |
359 | */ | |
360 | void sctp_transport_raise_cwnd(struct sctp_transport *transport, | |
361 | __u32 sack_ctsn, __u32 bytes_acked) | |
362 | { | |
363 | __u32 cwnd, ssthresh, flight_size, pba, pmtu; | |
364 | ||
365 | cwnd = transport->cwnd; | |
366 | flight_size = transport->flight_size; | |
367 | ||
368 | /* The appropriate cwnd increase algorithm is performed if, and only | |
369 | * if the cumulative TSN has advanced and the congestion window is | |
370 | * being fully utilized. | |
371 | */ | |
372 | if ((transport->asoc->ctsn_ack_point >= sack_ctsn) || | |
373 | (flight_size < cwnd)) | |
374 | return; | |
375 | ||
376 | ssthresh = transport->ssthresh; | |
377 | pba = transport->partial_bytes_acked; | |
52ccb8e9 | 378 | pmtu = transport->asoc->pathmtu; |
1da177e4 LT |
379 | |
380 | if (cwnd <= ssthresh) { | |
381 | /* RFC 2960 7.2.1, sctpimpguide-05 2.14.2 When cwnd is less | |
382 | * than or equal to ssthresh an SCTP endpoint MUST use the | |
383 | * slow start algorithm to increase cwnd only if the current | |
384 | * congestion window is being fully utilized and an incoming | |
385 | * SACK advances the Cumulative TSN Ack Point. Only when these | |
386 | * two conditions are met can the cwnd be increased otherwise | |
387 | * the cwnd MUST not be increased. If these conditions are met | |
388 | * then cwnd MUST be increased by at most the lesser of | |
389 | * 1) the total size of the previously outstanding DATA | |
390 | * chunk(s) acknowledged, and 2) the destination's path MTU. | |
391 | */ | |
392 | if (bytes_acked > pmtu) | |
393 | cwnd += pmtu; | |
394 | else | |
395 | cwnd += bytes_acked; | |
396 | SCTP_DEBUG_PRINTK("%s: SLOW START: transport: %p, " | |
397 | "bytes_acked: %d, cwnd: %d, ssthresh: %d, " | |
398 | "flight_size: %d, pba: %d\n", | |
399 | __FUNCTION__, | |
400 | transport, bytes_acked, cwnd, | |
401 | ssthresh, flight_size, pba); | |
402 | } else { | |
403 | /* RFC 2960 7.2.2 Whenever cwnd is greater than ssthresh, | |
404 | * upon each SACK arrival that advances the Cumulative TSN Ack | |
405 | * Point, increase partial_bytes_acked by the total number of | |
406 | * bytes of all new chunks acknowledged in that SACK including | |
407 | * chunks acknowledged by the new Cumulative TSN Ack and by | |
408 | * Gap Ack Blocks. | |
409 | * | |
410 | * When partial_bytes_acked is equal to or greater than cwnd | |
411 | * and before the arrival of the SACK the sender had cwnd or | |
412 | * more bytes of data outstanding (i.e., before arrival of the | |
413 | * SACK, flightsize was greater than or equal to cwnd), | |
414 | * increase cwnd by MTU, and reset partial_bytes_acked to | |
415 | * (partial_bytes_acked - cwnd). | |
416 | */ | |
417 | pba += bytes_acked; | |
418 | if (pba >= cwnd) { | |
419 | cwnd += pmtu; | |
420 | pba = ((cwnd < pba) ? (pba - cwnd) : 0); | |
421 | } | |
422 | SCTP_DEBUG_PRINTK("%s: CONGESTION AVOIDANCE: " | |
423 | "transport: %p, bytes_acked: %d, cwnd: %d, " | |
424 | "ssthresh: %d, flight_size: %d, pba: %d\n", | |
425 | __FUNCTION__, | |
426 | transport, bytes_acked, cwnd, | |
427 | ssthresh, flight_size, pba); | |
428 | } | |
429 | ||
430 | transport->cwnd = cwnd; | |
431 | transport->partial_bytes_acked = pba; | |
432 | } | |
433 | ||
434 | /* This routine is used to lower the transport's cwnd when congestion is | |
435 | * detected. | |
436 | */ | |
437 | void sctp_transport_lower_cwnd(struct sctp_transport *transport, | |
438 | sctp_lower_cwnd_t reason) | |
439 | { | |
440 | switch (reason) { | |
441 | case SCTP_LOWER_CWND_T3_RTX: | |
442 | /* RFC 2960 Section 7.2.3, sctpimpguide | |
443 | * When the T3-rtx timer expires on an address, SCTP should | |
444 | * perform slow start by: | |
445 | * ssthresh = max(cwnd/2, 4*MTU) | |
446 | * cwnd = 1*MTU | |
447 | * partial_bytes_acked = 0 | |
448 | */ | |
449 | transport->ssthresh = max(transport->cwnd/2, | |
52ccb8e9 FF |
450 | 4*transport->asoc->pathmtu); |
451 | transport->cwnd = transport->asoc->pathmtu; | |
1da177e4 LT |
452 | break; |
453 | ||
454 | case SCTP_LOWER_CWND_FAST_RTX: | |
455 | /* RFC 2960 7.2.4 Adjust the ssthresh and cwnd of the | |
456 | * destination address(es) to which the missing DATA chunks | |
457 | * were last sent, according to the formula described in | |
458 | * Section 7.2.3. | |
459 | * | |
460 | * RFC 2960 7.2.3, sctpimpguide Upon detection of packet | |
461 | * losses from SACK (see Section 7.2.4), An endpoint | |
462 | * should do the following: | |
463 | * ssthresh = max(cwnd/2, 4*MTU) | |
464 | * cwnd = ssthresh | |
465 | * partial_bytes_acked = 0 | |
466 | */ | |
467 | transport->ssthresh = max(transport->cwnd/2, | |
52ccb8e9 | 468 | 4*transport->asoc->pathmtu); |
1da177e4 LT |
469 | transport->cwnd = transport->ssthresh; |
470 | break; | |
471 | ||
472 | case SCTP_LOWER_CWND_ECNE: | |
473 | /* RFC 2481 Section 6.1.2. | |
474 | * If the sender receives an ECN-Echo ACK packet | |
475 | * then the sender knows that congestion was encountered in the | |
476 | * network on the path from the sender to the receiver. The | |
477 | * indication of congestion should be treated just as a | |
478 | * congestion loss in non-ECN Capable TCP. That is, the TCP | |
479 | * source halves the congestion window "cwnd" and reduces the | |
480 | * slow start threshold "ssthresh". | |
481 | * A critical condition is that TCP does not react to | |
482 | * congestion indications more than once every window of | |
483 | * data (or more loosely more than once every round-trip time). | |
484 | */ | |
485 | if ((jiffies - transport->last_time_ecne_reduced) > | |
486 | transport->rtt) { | |
487 | transport->ssthresh = max(transport->cwnd/2, | |
52ccb8e9 | 488 | 4*transport->asoc->pathmtu); |
1da177e4 LT |
489 | transport->cwnd = transport->ssthresh; |
490 | transport->last_time_ecne_reduced = jiffies; | |
491 | } | |
492 | break; | |
493 | ||
494 | case SCTP_LOWER_CWND_INACTIVE: | |
495 | /* RFC 2960 Section 7.2.1, sctpimpguide | |
496 | * When the endpoint does not transmit data on a given | |
497 | * transport address, the cwnd of the transport address | |
498 | * should be adjusted to max(cwnd/2, 4*MTU) per RTO. | |
499 | * NOTE: Although the draft recommends that this check needs | |
500 | * to be done every RTO interval, we do it every hearbeat | |
501 | * interval. | |
502 | */ | |
503 | if ((jiffies - transport->last_time_used) > transport->rto) | |
504 | transport->cwnd = max(transport->cwnd/2, | |
52ccb8e9 | 505 | 4*transport->asoc->pathmtu); |
1da177e4 LT |
506 | break; |
507 | }; | |
508 | ||
509 | transport->partial_bytes_acked = 0; | |
510 | SCTP_DEBUG_PRINTK("%s: transport: %p reason: %d cwnd: " | |
511 | "%d ssthresh: %d\n", __FUNCTION__, | |
512 | transport, reason, | |
513 | transport->cwnd, transport->ssthresh); | |
514 | } | |
515 | ||
516 | /* What is the next timeout value for this transport? */ | |
517 | unsigned long sctp_transport_timeout(struct sctp_transport *t) | |
518 | { | |
519 | unsigned long timeout; | |
52ccb8e9 | 520 | timeout = t->hbinterval + t->rto + sctp_jitter(t->rto); |
1da177e4 LT |
521 | timeout += jiffies; |
522 | return timeout; | |
523 | } |