sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
[linux-3.10.git] / net / sctp / sm_sideeffect.c
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  *
6  * This file is part of the SCTP kernel implementation
7  *
8  * These functions work with the state functions in sctp_sm_statefuns.c
9  * to implement that state operations.  These functions implement the
10  * steps which require modifying existing data structures.
11  *
12  * This SCTP implementation is free software;
13  * you can redistribute it and/or modify it under the terms of
14  * the GNU General Public License as published by
15  * the Free Software Foundation; either version 2, or (at your option)
16  * any later version.
17  *
18  * This SCTP implementation is distributed in the hope that it
19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20  *                 ************************
21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22  * See the GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with GNU CC; see the file COPYING.  If not, write to
26  * the Free Software Foundation, 59 Temple Place - Suite 330,
27  * Boston, MA 02111-1307, USA.
28  *
29  * Please send any bug reports or fixes you make to the
30  * email address(es):
31  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
32  *
33  * Or submit a bug report through the following website:
34  *    http://www.sf.net/projects/lksctp
35  *
36  * Written or modified by:
37  *    La Monte H.P. Yarroll <piggy@acm.org>
38  *    Karl Knutson          <karl@athena.chicago.il.us>
39  *    Jon Grimm             <jgrimm@austin.ibm.com>
40  *    Hui Huang             <hui.huang@nokia.com>
41  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
42  *    Daisy Chang           <daisyc@us.ibm.com>
43  *    Sridhar Samudrala     <sri@us.ibm.com>
44  *    Ardelle Fan           <ardelle.fan@intel.com>
45  *
46  * Any bugs reported given to us we will try to fix... any fixes shared will
47  * be incorporated into the next SCTP release.
48  */
49
50 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
51
52 #include <linux/skbuff.h>
53 #include <linux/types.h>
54 #include <linux/socket.h>
55 #include <linux/ip.h>
56 #include <linux/gfp.h>
57 #include <net/sock.h>
58 #include <net/sctp/sctp.h>
59 #include <net/sctp/sm.h>
60
61 static int sctp_cmd_interpreter(sctp_event_t event_type,
62                                 sctp_subtype_t subtype,
63                                 sctp_state_t state,
64                                 struct sctp_endpoint *ep,
65                                 struct sctp_association *asoc,
66                                 void *event_arg,
67                                 sctp_disposition_t status,
68                                 sctp_cmd_seq_t *commands,
69                                 gfp_t gfp);
70 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
71                              sctp_state_t state,
72                              struct sctp_endpoint *ep,
73                              struct sctp_association *asoc,
74                              void *event_arg,
75                              sctp_disposition_t status,
76                              sctp_cmd_seq_t *commands,
77                              gfp_t gfp);
78
79 /********************************************************************
80  * Helper functions
81  ********************************************************************/
82
83 /* A helper function for delayed processing of INET ECN CE bit. */
84 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
85                                 __u32 lowest_tsn)
86 {
87         /* Save the TSN away for comparison when we receive CWR */
88
89         asoc->last_ecne_tsn = lowest_tsn;
90         asoc->need_ecne = 1;
91 }
92
93 /* Helper function for delayed processing of SCTP ECNE chunk.  */
94 /* RFC 2960 Appendix A
95  *
96  * RFC 2481 details a specific bit for a sender to send in
97  * the header of its next outbound TCP segment to indicate to
98  * its peer that it has reduced its congestion window.  This
99  * is termed the CWR bit.  For SCTP the same indication is made
100  * by including the CWR chunk.  This chunk contains one data
101  * element, i.e. the TSN number that was sent in the ECNE chunk.
102  * This element represents the lowest TSN number in the datagram
103  * that was originally marked with the CE bit.
104  */
105 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
106                                            __u32 lowest_tsn,
107                                            struct sctp_chunk *chunk)
108 {
109         struct sctp_chunk *repl;
110
111         /* Our previously transmitted packet ran into some congestion
112          * so we should take action by reducing cwnd and ssthresh
113          * and then ACK our peer that we we've done so by
114          * sending a CWR.
115          */
116
117         /* First, try to determine if we want to actually lower
118          * our cwnd variables.  Only lower them if the ECNE looks more
119          * recent than the last response.
120          */
121         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
122                 struct sctp_transport *transport;
123
124                 /* Find which transport's congestion variables
125                  * need to be adjusted.
126                  */
127                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
128
129                 /* Update the congestion variables. */
130                 if (transport)
131                         sctp_transport_lower_cwnd(transport,
132                                                   SCTP_LOWER_CWND_ECNE);
133                 asoc->last_cwr_tsn = lowest_tsn;
134         }
135
136         /* Always try to quiet the other end.  In case of lost CWR,
137          * resend last_cwr_tsn.
138          */
139         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
140
141         /* If we run out of memory, it will look like a lost CWR.  We'll
142          * get back in sync eventually.
143          */
144         return repl;
145 }
146
147 /* Helper function to do delayed processing of ECN CWR chunk.  */
148 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
149                                  __u32 lowest_tsn)
150 {
151         /* Turn off ECNE getting auto-prepended to every outgoing
152          * packet
153          */
154         asoc->need_ecne = 0;
155 }
156
157 /* Generate SACK if necessary.  We call this at the end of a packet.  */
158 static int sctp_gen_sack(struct sctp_association *asoc, int force,
159                          sctp_cmd_seq_t *commands)
160 {
161         __u32 ctsn, max_tsn_seen;
162         struct sctp_chunk *sack;
163         struct sctp_transport *trans = asoc->peer.last_data_from;
164         int error = 0;
165
166         if (force ||
167             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
168             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
169                 asoc->peer.sack_needed = 1;
170
171         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
172         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
173
174         /* From 12.2 Parameters necessary per association (i.e. the TCB):
175          *
176          * Ack State : This flag indicates if the next received packet
177          *           : is to be responded to with a SACK. ...
178          *           : When DATA chunks are out of order, SACK's
179          *           : are not delayed (see Section 6).
180          *
181          * [This is actually not mentioned in Section 6, but we
182          * implement it here anyway. --piggy]
183          */
184         if (max_tsn_seen != ctsn)
185                 asoc->peer.sack_needed = 1;
186
187         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
188          *
189          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
190          * an acknowledgement SHOULD be generated for at least every
191          * second packet (not every second DATA chunk) received, and
192          * SHOULD be generated within 200 ms of the arrival of any
193          * unacknowledged DATA chunk. ...
194          */
195         if (!asoc->peer.sack_needed) {
196                 asoc->peer.sack_cnt++;
197
198                 /* Set the SACK delay timeout based on the
199                  * SACK delay for the last transport
200                  * data was received from, or the default
201                  * for the association.
202                  */
203                 if (trans) {
204                         /* We will need a SACK for the next packet.  */
205                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
206                                 asoc->peer.sack_needed = 1;
207
208                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
209                                 trans->sackdelay;
210                 } else {
211                         /* We will need a SACK for the next packet.  */
212                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
213                                 asoc->peer.sack_needed = 1;
214
215                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
216                                 asoc->sackdelay;
217                 }
218
219                 /* Restart the SACK timer. */
220                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
221                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
222         } else {
223                 asoc->a_rwnd = asoc->rwnd;
224                 sack = sctp_make_sack(asoc);
225                 if (!sack)
226                         goto nomem;
227
228                 asoc->peer.sack_needed = 0;
229                 asoc->peer.sack_cnt = 0;
230
231                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
232
233                 /* Stop the SACK timer.  */
234                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
235                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
236         }
237
238         return error;
239 nomem:
240         error = -ENOMEM;
241         return error;
242 }
243
244 /* When the T3-RTX timer expires, it calls this function to create the
245  * relevant state machine event.
246  */
247 void sctp_generate_t3_rtx_event(unsigned long peer)
248 {
249         int error;
250         struct sctp_transport *transport = (struct sctp_transport *) peer;
251         struct sctp_association *asoc = transport->asoc;
252
253         /* Check whether a task is in the sock.  */
254
255         sctp_bh_lock_sock(asoc->base.sk);
256         if (sock_owned_by_user(asoc->base.sk)) {
257                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
258
259                 /* Try again later.  */
260                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
261                         sctp_transport_hold(transport);
262                 goto out_unlock;
263         }
264
265         /* Is this transport really dead and just waiting around for
266          * the timer to let go of the reference?
267          */
268         if (transport->dead)
269                 goto out_unlock;
270
271         /* Run through the state machine.  */
272         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
273                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
274                            asoc->state,
275                            asoc->ep, asoc,
276                            transport, GFP_ATOMIC);
277
278         if (error)
279                 asoc->base.sk->sk_err = -error;
280
281 out_unlock:
282         sctp_bh_unlock_sock(asoc->base.sk);
283         sctp_transport_put(transport);
284 }
285
286 /* This is a sa interface for producing timeout events.  It works
287  * for timeouts which use the association as their parameter.
288  */
289 static void sctp_generate_timeout_event(struct sctp_association *asoc,
290                                         sctp_event_timeout_t timeout_type)
291 {
292         int error = 0;
293
294         sctp_bh_lock_sock(asoc->base.sk);
295         if (sock_owned_by_user(asoc->base.sk)) {
296                 SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
297                                   __func__,
298                                   timeout_type);
299
300                 /* Try again later.  */
301                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
302                         sctp_association_hold(asoc);
303                 goto out_unlock;
304         }
305
306         /* Is this association really dead and just waiting around for
307          * the timer to let go of the reference?
308          */
309         if (asoc->base.dead)
310                 goto out_unlock;
311
312         /* Run through the state machine.  */
313         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
314                            SCTP_ST_TIMEOUT(timeout_type),
315                            asoc->state, asoc->ep, asoc,
316                            (void *)timeout_type, GFP_ATOMIC);
317
318         if (error)
319                 asoc->base.sk->sk_err = -error;
320
321 out_unlock:
322         sctp_bh_unlock_sock(asoc->base.sk);
323         sctp_association_put(asoc);
324 }
325
326 static void sctp_generate_t1_cookie_event(unsigned long data)
327 {
328         struct sctp_association *asoc = (struct sctp_association *) data;
329         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
330 }
331
332 static void sctp_generate_t1_init_event(unsigned long data)
333 {
334         struct sctp_association *asoc = (struct sctp_association *) data;
335         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
336 }
337
338 static void sctp_generate_t2_shutdown_event(unsigned long data)
339 {
340         struct sctp_association *asoc = (struct sctp_association *) data;
341         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
342 }
343
344 static void sctp_generate_t4_rto_event(unsigned long data)
345 {
346         struct sctp_association *asoc = (struct sctp_association *) data;
347         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
348 }
349
350 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
351 {
352         struct sctp_association *asoc = (struct sctp_association *)data;
353         sctp_generate_timeout_event(asoc,
354                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
355
356 } /* sctp_generate_t5_shutdown_guard_event() */
357
358 static void sctp_generate_autoclose_event(unsigned long data)
359 {
360         struct sctp_association *asoc = (struct sctp_association *) data;
361         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
362 }
363
364 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
365  * sure that the transport is still valid.
366  */
367 void sctp_generate_heartbeat_event(unsigned long data)
368 {
369         int error = 0;
370         struct sctp_transport *transport = (struct sctp_transport *) data;
371         struct sctp_association *asoc = transport->asoc;
372
373         sctp_bh_lock_sock(asoc->base.sk);
374         if (sock_owned_by_user(asoc->base.sk)) {
375                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
376
377                 /* Try again later.  */
378                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
379                         sctp_transport_hold(transport);
380                 goto out_unlock;
381         }
382
383         /* Is this structure just waiting around for us to actually
384          * get destroyed?
385          */
386         if (transport->dead)
387                 goto out_unlock;
388
389         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
390                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
391                            asoc->state, asoc->ep, asoc,
392                            transport, GFP_ATOMIC);
393
394          if (error)
395                  asoc->base.sk->sk_err = -error;
396
397 out_unlock:
398         sctp_bh_unlock_sock(asoc->base.sk);
399         sctp_transport_put(transport);
400 }
401
402 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
403  * the correct state machine transition that will close the association.
404  */
405 void sctp_generate_proto_unreach_event(unsigned long data)
406 {
407         struct sctp_transport *transport = (struct sctp_transport *) data;
408         struct sctp_association *asoc = transport->asoc;
409         
410         sctp_bh_lock_sock(asoc->base.sk);
411         if (sock_owned_by_user(asoc->base.sk)) {
412                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
413
414                 /* Try again later.  */
415                 if (!mod_timer(&transport->proto_unreach_timer,
416                                 jiffies + (HZ/20)))
417                         sctp_association_hold(asoc);
418                 goto out_unlock;
419         }
420
421         /* Is this structure just waiting around for us to actually
422          * get destroyed?
423          */
424         if (asoc->base.dead)
425                 goto out_unlock;
426
427         sctp_do_sm(SCTP_EVENT_T_OTHER,
428                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
429                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
430
431 out_unlock:
432         sctp_bh_unlock_sock(asoc->base.sk);
433         sctp_association_put(asoc);
434 }
435
436
437 /* Inject a SACK Timeout event into the state machine.  */
438 static void sctp_generate_sack_event(unsigned long data)
439 {
440         struct sctp_association *asoc = (struct sctp_association *) data;
441         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
442 }
443
444 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
445         NULL,
446         sctp_generate_t1_cookie_event,
447         sctp_generate_t1_init_event,
448         sctp_generate_t2_shutdown_event,
449         NULL,
450         sctp_generate_t4_rto_event,
451         sctp_generate_t5_shutdown_guard_event,
452         NULL,
453         sctp_generate_sack_event,
454         sctp_generate_autoclose_event,
455 };
456
457
458 /* RFC 2960 8.2 Path Failure Detection
459  *
460  * When its peer endpoint is multi-homed, an endpoint should keep a
461  * error counter for each of the destination transport addresses of the
462  * peer endpoint.
463  *
464  * Each time the T3-rtx timer expires on any address, or when a
465  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
466  * the error counter of that destination address will be incremented.
467  * When the value in the error counter exceeds the protocol parameter
468  * 'Path.Max.Retrans' of that destination address, the endpoint should
469  * mark the destination transport address as inactive, and a
470  * notification SHOULD be sent to the upper layer.
471  *
472  */
473 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
474                                          struct sctp_transport *transport,
475                                          int is_hb)
476 {
477         /* The check for association's overall error counter exceeding the
478          * threshold is done in the state function.
479          */
480         /* We are here due to a timer expiration.  If the timer was
481          * not a HEARTBEAT, then normal error tracking is done.
482          * If the timer was a heartbeat, we only increment error counts
483          * when we already have an outstanding HEARTBEAT that has not
484          * been acknowledged.
485          * Additionally, some tranport states inhibit error increments.
486          */
487         if (!is_hb) {
488                 asoc->overall_error_count++;
489                 if (transport->state != SCTP_INACTIVE)
490                         transport->error_count++;
491          } else if (transport->hb_sent) {
492                 if (transport->state != SCTP_UNCONFIRMED)
493                         asoc->overall_error_count++;
494                 if (transport->state != SCTP_INACTIVE)
495                         transport->error_count++;
496         }
497
498         if (transport->state != SCTP_INACTIVE &&
499             (transport->error_count > transport->pathmaxrxt)) {
500                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
501                                          " transport IP: port:%d failed.\n",
502                                          asoc,
503                                          (&transport->ipaddr),
504                                          ntohs(transport->ipaddr.v4.sin_port));
505                 sctp_assoc_control_transport(asoc, transport,
506                                              SCTP_TRANSPORT_DOWN,
507                                              SCTP_FAILED_THRESHOLD);
508         }
509
510         /* E2) For the destination address for which the timer
511          * expires, set RTO <- RTO * 2 ("back off the timer").  The
512          * maximum value discussed in rule C7 above (RTO.max) may be
513          * used to provide an upper bound to this doubling operation.
514          *
515          * Special Case:  the first HB doesn't trigger exponential backoff.
516          * The first unacknowledged HB triggers it.  We do this with a flag
517          * that indicates that we have an outstanding HB.
518          */
519         if (!is_hb || transport->hb_sent) {
520                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
521         }
522 }
523
524 /* Worker routine to handle INIT command failure.  */
525 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
526                                  struct sctp_association *asoc,
527                                  unsigned error)
528 {
529         struct sctp_ulpevent *event;
530
531         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
532                                                 (__u16)error, 0, 0, NULL,
533                                                 GFP_ATOMIC);
534
535         if (event)
536                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
537                                 SCTP_ULPEVENT(event));
538
539         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
540                         SCTP_STATE(SCTP_STATE_CLOSED));
541
542         /* SEND_FAILED sent later when cleaning up the association. */
543         asoc->outqueue.error = error;
544         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
545 }
546
547 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
548 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
549                                   struct sctp_association *asoc,
550                                   sctp_event_t event_type,
551                                   sctp_subtype_t subtype,
552                                   struct sctp_chunk *chunk,
553                                   unsigned error)
554 {
555         struct sctp_ulpevent *event;
556
557         /* Cancel any partial delivery in progress. */
558         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
559
560         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
561                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
562                                                 (__u16)error, 0, 0, chunk,
563                                                 GFP_ATOMIC);
564         else
565                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
566                                                 (__u16)error, 0, 0, NULL,
567                                                 GFP_ATOMIC);
568         if (event)
569                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
570                                 SCTP_ULPEVENT(event));
571
572         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
573                         SCTP_STATE(SCTP_STATE_CLOSED));
574
575         /* SEND_FAILED sent later when cleaning up the association. */
576         asoc->outqueue.error = error;
577         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
578 }
579
580 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
581  * inside the cookie.  In reality, this is only used for INIT-ACK processing
582  * since all other cases use "temporary" associations and can do all
583  * their work in statefuns directly.
584  */
585 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
586                                  struct sctp_association *asoc,
587                                  struct sctp_chunk *chunk,
588                                  sctp_init_chunk_t *peer_init,
589                                  gfp_t gfp)
590 {
591         int error;
592
593         /* We only process the init as a sideeffect in a single
594          * case.   This is when we process the INIT-ACK.   If we
595          * fail during INIT processing (due to malloc problems),
596          * just return the error and stop processing the stack.
597          */
598         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
599                 error = -ENOMEM;
600         else
601                 error = 0;
602
603         return error;
604 }
605
606 /* Helper function to break out starting up of heartbeat timers.  */
607 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
608                                      struct sctp_association *asoc)
609 {
610         struct sctp_transport *t;
611
612         /* Start a heartbeat timer for each transport on the association.
613          * hold a reference on the transport to make sure none of
614          * the needed data structures go away.
615          */
616         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
617
618                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
619                         sctp_transport_hold(t);
620         }
621 }
622
623 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
624                                     struct sctp_association *asoc)
625 {
626         struct sctp_transport *t;
627
628         /* Stop all heartbeat timers. */
629
630         list_for_each_entry(t, &asoc->peer.transport_addr_list,
631                         transports) {
632                 if (del_timer(&t->hb_timer))
633                         sctp_transport_put(t);
634         }
635 }
636
637 /* Helper function to stop any pending T3-RTX timers */
638 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
639                                         struct sctp_association *asoc)
640 {
641         struct sctp_transport *t;
642
643         list_for_each_entry(t, &asoc->peer.transport_addr_list,
644                         transports) {
645                 if (timer_pending(&t->T3_rtx_timer) &&
646                     del_timer(&t->T3_rtx_timer)) {
647                         sctp_transport_put(t);
648                 }
649         }
650 }
651
652
653 /* Helper function to update the heartbeat timer. */
654 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
655                                      struct sctp_transport *t)
656 {
657         /* Update the heartbeat timer.  */
658         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
659                 sctp_transport_hold(t);
660 }
661
662 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
663 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
664                                   struct sctp_association *asoc,
665                                   struct sctp_transport *t,
666                                   struct sctp_chunk *chunk)
667 {
668         sctp_sender_hb_info_t *hbinfo;
669
670         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
671          * HEARTBEAT should clear the error counter of the destination
672          * transport address to which the HEARTBEAT was sent.
673          */
674         t->error_count = 0;
675
676         /*
677          * Although RFC4960 specifies that the overall error count must
678          * be cleared when a HEARTBEAT ACK is received, we make an
679          * exception while in SHUTDOWN PENDING. If the peer keeps its
680          * window shut forever, we may never be able to transmit our
681          * outstanding data and rely on the retransmission limit be reached
682          * to shutdown the association.
683          */
684         if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
685                 t->asoc->overall_error_count = 0;
686
687         /* Clear the hb_sent flag to signal that we had a good
688          * acknowledgement.
689          */
690         t->hb_sent = 0;
691
692         /* Mark the destination transport address as active if it is not so
693          * marked.
694          */
695         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
696                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
697                                              SCTP_HEARTBEAT_SUCCESS);
698
699         /* The receiver of the HEARTBEAT ACK should also perform an
700          * RTT measurement for that destination transport address
701          * using the time value carried in the HEARTBEAT ACK chunk.
702          * If the transport's rto_pending variable has been cleared,
703          * it was most likely due to a retransmit.  However, we want
704          * to re-enable it to properly update the rto.
705          */
706         if (t->rto_pending == 0)
707                 t->rto_pending = 1;
708
709         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
710         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
711
712         /* Update the heartbeat timer.  */
713         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
714                 sctp_transport_hold(t);
715 }
716
717
718 /* Helper function to process the process SACK command.  */
719 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
720                                  struct sctp_association *asoc,
721                                  struct sctp_sackhdr *sackh)
722 {
723         int err = 0;
724
725         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
726                 /* There are no more TSNs awaiting SACK.  */
727                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
728                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
729                                  asoc->state, asoc->ep, asoc, NULL,
730                                  GFP_ATOMIC);
731         }
732
733         return err;
734 }
735
736 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
737  * the transport for a shutdown chunk.
738  */
739 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
740                               struct sctp_association *asoc,
741                               struct sctp_chunk *chunk)
742 {
743         struct sctp_transport *t;
744
745         if (chunk->transport)
746                 t = chunk->transport;
747         else {
748                 t = sctp_assoc_choose_alter_transport(asoc,
749                                               asoc->shutdown_last_sent_to);
750                 chunk->transport = t;
751         }
752         asoc->shutdown_last_sent_to = t;
753         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
754 }
755
756 /* Helper function to change the state of an association. */
757 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
758                                struct sctp_association *asoc,
759                                sctp_state_t state)
760 {
761         struct sock *sk = asoc->base.sk;
762
763         asoc->state = state;
764
765         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
766                           asoc, sctp_state_tbl[state]);
767
768         if (sctp_style(sk, TCP)) {
769                 /* Change the sk->sk_state of a TCP-style socket that has
770                  * successfully completed a connect() call.
771                  */
772                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
773                         sk->sk_state = SCTP_SS_ESTABLISHED;
774
775                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
776                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
777                     sctp_sstate(sk, ESTABLISHED))
778                         sk->sk_shutdown |= RCV_SHUTDOWN;
779         }
780
781         if (sctp_state(asoc, COOKIE_WAIT)) {
782                 /* Reset init timeouts since they may have been
783                  * increased due to timer expirations.
784                  */
785                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
786                                                 asoc->rto_initial;
787                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
788                                                 asoc->rto_initial;
789         }
790
791         if (sctp_state(asoc, ESTABLISHED) ||
792             sctp_state(asoc, CLOSED) ||
793             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
794                 /* Wake up any processes waiting in the asoc's wait queue in
795                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
796                  */
797                 if (waitqueue_active(&asoc->wait))
798                         wake_up_interruptible(&asoc->wait);
799
800                 /* Wake up any processes waiting in the sk's sleep queue of
801                  * a TCP-style or UDP-style peeled-off socket in
802                  * sctp_wait_for_accept() or sctp_wait_for_packet().
803                  * For a UDP-style socket, the waiters are woken up by the
804                  * notifications.
805                  */
806                 if (!sctp_style(sk, UDP))
807                         sk->sk_state_change(sk);
808         }
809 }
810
811 /* Helper function to delete an association. */
812 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
813                                 struct sctp_association *asoc)
814 {
815         struct sock *sk = asoc->base.sk;
816
817         /* If it is a non-temporary association belonging to a TCP-style
818          * listening socket that is not closed, do not free it so that accept()
819          * can pick it up later.
820          */
821         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
822             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
823                 return;
824
825         sctp_unhash_established(asoc);
826         sctp_association_free(asoc);
827 }
828
829 /*
830  * ADDIP Section 4.1 ASCONF Chunk Procedures
831  * A4) Start a T-4 RTO timer, using the RTO value of the selected
832  * destination address (we use active path instead of primary path just
833  * because primary path may be inactive.
834  */
835 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
836                                 struct sctp_association *asoc,
837                                 struct sctp_chunk *chunk)
838 {
839         struct sctp_transport *t;
840
841         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
842         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
843         chunk->transport = t;
844 }
845
846 /* Process an incoming Operation Error Chunk. */
847 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
848                                    struct sctp_association *asoc,
849                                    struct sctp_chunk *chunk)
850 {
851         struct sctp_errhdr *err_hdr;
852         struct sctp_ulpevent *ev;
853
854         while (chunk->chunk_end > chunk->skb->data) {
855                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
856
857                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
858                                                      GFP_ATOMIC);
859                 if (!ev)
860                         return;
861
862                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
863
864                 switch (err_hdr->cause) {
865                 case SCTP_ERROR_UNKNOWN_CHUNK:
866                 {
867                         sctp_chunkhdr_t *unk_chunk_hdr;
868
869                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
870                         switch (unk_chunk_hdr->type) {
871                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
872                          * an ERROR chunk reporting that it did not recognized
873                          * the ASCONF chunk type, the sender of the ASCONF MUST
874                          * NOT send any further ASCONF chunks and MUST stop its
875                          * T-4 timer.
876                          */
877                         case SCTP_CID_ASCONF:
878                                 if (asoc->peer.asconf_capable == 0)
879                                         break;
880
881                                 asoc->peer.asconf_capable = 0;
882                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
883                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
884                                 break;
885                         default:
886                                 break;
887                         }
888                         break;
889                 }
890                 default:
891                         break;
892                 }
893         }
894 }
895
896 /* Process variable FWDTSN chunk information. */
897 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
898                                     struct sctp_chunk *chunk)
899 {
900         struct sctp_fwdtsn_skip *skip;
901         /* Walk through all the skipped SSNs */
902         sctp_walk_fwdtsn(skip, chunk) {
903                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
904         }
905 }
906
907 /* Helper function to remove the association non-primary peer
908  * transports.
909  */
910 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
911 {
912         struct sctp_transport *t;
913         struct list_head *pos;
914         struct list_head *temp;
915
916         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
917                 t = list_entry(pos, struct sctp_transport, transports);
918                 if (!sctp_cmp_addr_exact(&t->ipaddr,
919                                          &asoc->peer.primary_addr)) {
920                         sctp_assoc_del_peer(asoc, &t->ipaddr);
921                 }
922         }
923 }
924
925 /* Helper function to set sk_err on a 1-1 style socket. */
926 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
927 {
928         struct sock *sk = asoc->base.sk;
929
930         if (!sctp_style(sk, UDP))
931                 sk->sk_err = error;
932 }
933
934 /* Helper function to generate an association change event */
935 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
936                                  struct sctp_association *asoc,
937                                  u8 state)
938 {
939         struct sctp_ulpevent *ev;
940
941         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
942                                             asoc->c.sinit_num_ostreams,
943                                             asoc->c.sinit_max_instreams,
944                                             NULL, GFP_ATOMIC);
945         if (ev)
946                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
947 }
948
949 /* Helper function to generate an adaptation indication event */
950 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
951                                     struct sctp_association *asoc)
952 {
953         struct sctp_ulpevent *ev;
954
955         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
956
957         if (ev)
958                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
959 }
960
961
962 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
963                                     sctp_event_timeout_t timer,
964                                     char *name)
965 {
966         struct sctp_transport *t;
967
968         t = asoc->init_last_sent_to;
969         asoc->init_err_counter++;
970
971         if (t->init_sent_count > (asoc->init_cycle + 1)) {
972                 asoc->timeouts[timer] *= 2;
973                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
974                         asoc->timeouts[timer] = asoc->max_init_timeo;
975                 }
976                 asoc->init_cycle++;
977                 SCTP_DEBUG_PRINTK(
978                         "T1 %s Timeout adjustment"
979                         " init_err_counter: %d"
980                         " cycle: %d"
981                         " timeout: %ld\n",
982                         name,
983                         asoc->init_err_counter,
984                         asoc->init_cycle,
985                         asoc->timeouts[timer]);
986         }
987
988 }
989
990 /* Send the whole message, chunk by chunk, to the outqueue.
991  * This way the whole message is queued up and bundling if
992  * encouraged for small fragments.
993  */
994 static int sctp_cmd_send_msg(struct sctp_association *asoc,
995                                 struct sctp_datamsg *msg)
996 {
997         struct sctp_chunk *chunk;
998         int error = 0;
999
1000         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1001                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1002                 if (error)
1003                         break;
1004         }
1005
1006         return error;
1007 }
1008
1009
1010 /* Sent the next ASCONF packet currently stored in the association.
1011  * This happens after the ASCONF_ACK was succeffully processed.
1012  */
1013 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1014 {
1015         /* Send the next asconf chunk from the addip chunk
1016          * queue.
1017          */
1018         if (!list_empty(&asoc->addip_chunk_list)) {
1019                 struct list_head *entry = asoc->addip_chunk_list.next;
1020                 struct sctp_chunk *asconf = list_entry(entry,
1021                                                 struct sctp_chunk, list);
1022                 list_del_init(entry);
1023
1024                 /* Hold the chunk until an ASCONF_ACK is received. */
1025                 sctp_chunk_hold(asconf);
1026                 if (sctp_primitive_ASCONF(asoc, asconf))
1027                         sctp_chunk_free(asconf);
1028                 else
1029                         asoc->addip_last_asconf = asconf;
1030         }
1031 }
1032
1033
1034 /* These three macros allow us to pull the debugging code out of the
1035  * main flow of sctp_do_sm() to keep attention focused on the real
1036  * functionality there.
1037  */
1038 #define DEBUG_PRE \
1039         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1040                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
1041                           ep, sctp_evttype_tbl[event_type], \
1042                           (*debug_fn)(subtype), asoc, \
1043                           sctp_state_tbl[state], state_fn->name)
1044
1045 #define DEBUG_POST \
1046         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1047                           "asoc %p, status: %s\n", \
1048                           asoc, sctp_status_tbl[status])
1049
1050 #define DEBUG_POST_SFX \
1051         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1052                           error, asoc, \
1053                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1054                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1055
1056 /*
1057  * This is the master state machine processing function.
1058  *
1059  * If you want to understand all of lksctp, this is a
1060  * good place to start.
1061  */
1062 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
1063                sctp_state_t state,
1064                struct sctp_endpoint *ep,
1065                struct sctp_association *asoc,
1066                void *event_arg,
1067                gfp_t gfp)
1068 {
1069         sctp_cmd_seq_t commands;
1070         const sctp_sm_table_entry_t *state_fn;
1071         sctp_disposition_t status;
1072         int error = 0;
1073         typedef const char *(printfn_t)(sctp_subtype_t);
1074
1075         static printfn_t *table[] = {
1076                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1077         };
1078         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1079
1080         /* Look up the state function, run it, and then process the
1081          * side effects.  These three steps are the heart of lksctp.
1082          */
1083         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
1084
1085         sctp_init_cmd_seq(&commands);
1086
1087         DEBUG_PRE;
1088         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
1089         DEBUG_POST;
1090
1091         error = sctp_side_effects(event_type, subtype, state,
1092                                   ep, asoc, event_arg, status,
1093                                   &commands, gfp);
1094         DEBUG_POST_SFX;
1095
1096         return error;
1097 }
1098
1099 #undef DEBUG_PRE
1100 #undef DEBUG_POST
1101
1102 /*****************************************************************
1103  * This the master state function side effect processing function.
1104  *****************************************************************/
1105 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1106                              sctp_state_t state,
1107                              struct sctp_endpoint *ep,
1108                              struct sctp_association *asoc,
1109                              void *event_arg,
1110                              sctp_disposition_t status,
1111                              sctp_cmd_seq_t *commands,
1112                              gfp_t gfp)
1113 {
1114         int error;
1115
1116         /* FIXME - Most of the dispositions left today would be categorized
1117          * as "exceptional" dispositions.  For those dispositions, it
1118          * may not be proper to run through any of the commands at all.
1119          * For example, the command interpreter might be run only with
1120          * disposition SCTP_DISPOSITION_CONSUME.
1121          */
1122         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1123                                                ep, asoc,
1124                                                event_arg, status,
1125                                                commands, gfp)))
1126                 goto bail;
1127
1128         switch (status) {
1129         case SCTP_DISPOSITION_DISCARD:
1130                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1131                                   "event_type %d, event_id %d\n",
1132                                   state, event_type, subtype.chunk);
1133                 break;
1134
1135         case SCTP_DISPOSITION_NOMEM:
1136                 /* We ran out of memory, so we need to discard this
1137                  * packet.
1138                  */
1139                 /* BUG--we should now recover some memory, probably by
1140                  * reneging...
1141                  */
1142                 error = -ENOMEM;
1143                 break;
1144
1145         case SCTP_DISPOSITION_DELETE_TCB:
1146                 /* This should now be a command. */
1147                 break;
1148
1149         case SCTP_DISPOSITION_CONSUME:
1150         case SCTP_DISPOSITION_ABORT:
1151                 /*
1152                  * We should no longer have much work to do here as the
1153                  * real work has been done as explicit commands above.
1154                  */
1155                 break;
1156
1157         case SCTP_DISPOSITION_VIOLATION:
1158                 if (net_ratelimit())
1159                         pr_err("protocol violation state %d chunkid %d\n",
1160                                state, subtype.chunk);
1161                 break;
1162
1163         case SCTP_DISPOSITION_NOT_IMPL:
1164                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1165                         state, event_type, subtype.chunk);
1166                 break;
1167
1168         case SCTP_DISPOSITION_BUG:
1169                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1170                        state, event_type, subtype.chunk);
1171                 BUG();
1172                 break;
1173
1174         default:
1175                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1176                        status, state, event_type, subtype.chunk);
1177                 BUG();
1178                 break;
1179         }
1180
1181 bail:
1182         return error;
1183 }
1184
1185 /********************************************************************
1186  * 2nd Level Abstractions
1187  ********************************************************************/
1188
1189 /* This is the side-effect interpreter.  */
1190 static int sctp_cmd_interpreter(sctp_event_t event_type,
1191                                 sctp_subtype_t subtype,
1192                                 sctp_state_t state,
1193                                 struct sctp_endpoint *ep,
1194                                 struct sctp_association *asoc,
1195                                 void *event_arg,
1196                                 sctp_disposition_t status,
1197                                 sctp_cmd_seq_t *commands,
1198                                 gfp_t gfp)
1199 {
1200         int error = 0;
1201         int force;
1202         sctp_cmd_t *cmd;
1203         struct sctp_chunk *new_obj;
1204         struct sctp_chunk *chunk = NULL;
1205         struct sctp_packet *packet;
1206         struct timer_list *timer;
1207         unsigned long timeout;
1208         struct sctp_transport *t;
1209         struct sctp_sackhdr sackh;
1210         int local_cork = 0;
1211
1212         if (SCTP_EVENT_T_TIMEOUT != event_type)
1213                 chunk = event_arg;
1214
1215         /* Note:  This whole file is a huge candidate for rework.
1216          * For example, each command could either have its own handler, so
1217          * the loop would look like:
1218          *     while (cmds)
1219          *         cmd->handle(x, y, z)
1220          * --jgrimm
1221          */
1222         while (NULL != (cmd = sctp_next_cmd(commands))) {
1223                 switch (cmd->verb) {
1224                 case SCTP_CMD_NOP:
1225                         /* Do nothing. */
1226                         break;
1227
1228                 case SCTP_CMD_NEW_ASOC:
1229                         /* Register a new association.  */
1230                         if (local_cork) {
1231                                 sctp_outq_uncork(&asoc->outqueue);
1232                                 local_cork = 0;
1233                         }
1234                         asoc = cmd->obj.ptr;
1235                         /* Register with the endpoint.  */
1236                         sctp_endpoint_add_asoc(ep, asoc);
1237                         sctp_hash_established(asoc);
1238                         break;
1239
1240                 case SCTP_CMD_UPDATE_ASSOC:
1241                        sctp_assoc_update(asoc, cmd->obj.ptr);
1242                        break;
1243
1244                 case SCTP_CMD_PURGE_OUTQUEUE:
1245                        sctp_outq_teardown(&asoc->outqueue);
1246                        break;
1247
1248                 case SCTP_CMD_DELETE_TCB:
1249                         if (local_cork) {
1250                                 sctp_outq_uncork(&asoc->outqueue);
1251                                 local_cork = 0;
1252                         }
1253                         /* Delete the current association.  */
1254                         sctp_cmd_delete_tcb(commands, asoc);
1255                         asoc = NULL;
1256                         break;
1257
1258                 case SCTP_CMD_NEW_STATE:
1259                         /* Enter a new state.  */
1260                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1261                         break;
1262
1263                 case SCTP_CMD_REPORT_TSN:
1264                         /* Record the arrival of a TSN.  */
1265                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1266                                                  cmd->obj.u32);
1267                         break;
1268
1269                 case SCTP_CMD_REPORT_FWDTSN:
1270                         /* Move the Cumulattive TSN Ack ahead. */
1271                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1272
1273                         /* purge the fragmentation queue */
1274                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1275
1276                         /* Abort any in progress partial delivery. */
1277                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1278                         break;
1279
1280                 case SCTP_CMD_PROCESS_FWDTSN:
1281                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1282                         break;
1283
1284                 case SCTP_CMD_GEN_SACK:
1285                         /* Generate a Selective ACK.
1286                          * The argument tells us whether to just count
1287                          * the packet and MAYBE generate a SACK, or
1288                          * force a SACK out.
1289                          */
1290                         force = cmd->obj.i32;
1291                         error = sctp_gen_sack(asoc, force, commands);
1292                         break;
1293
1294                 case SCTP_CMD_PROCESS_SACK:
1295                         /* Process an inbound SACK.  */
1296                         error = sctp_cmd_process_sack(commands, asoc,
1297                                                       cmd->obj.ptr);
1298                         break;
1299
1300                 case SCTP_CMD_GEN_INIT_ACK:
1301                         /* Generate an INIT ACK chunk.  */
1302                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1303                                                      0);
1304                         if (!new_obj)
1305                                 goto nomem;
1306
1307                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1308                                         SCTP_CHUNK(new_obj));
1309                         break;
1310
1311                 case SCTP_CMD_PEER_INIT:
1312                         /* Process a unified INIT from the peer.
1313                          * Note: Only used during INIT-ACK processing.  If
1314                          * there is an error just return to the outter
1315                          * layer which will bail.
1316                          */
1317                         error = sctp_cmd_process_init(commands, asoc, chunk,
1318                                                       cmd->obj.ptr, gfp);
1319                         break;
1320
1321                 case SCTP_CMD_GEN_COOKIE_ECHO:
1322                         /* Generate a COOKIE ECHO chunk.  */
1323                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1324                         if (!new_obj) {
1325                                 if (cmd->obj.ptr)
1326                                         sctp_chunk_free(cmd->obj.ptr);
1327                                 goto nomem;
1328                         }
1329                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1330                                         SCTP_CHUNK(new_obj));
1331
1332                         /* If there is an ERROR chunk to be sent along with
1333                          * the COOKIE_ECHO, send it, too.
1334                          */
1335                         if (cmd->obj.ptr)
1336                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1337                                                 SCTP_CHUNK(cmd->obj.ptr));
1338
1339                         if (new_obj->transport) {
1340                                 new_obj->transport->init_sent_count++;
1341                                 asoc->init_last_sent_to = new_obj->transport;
1342                         }
1343
1344                         /* FIXME - Eventually come up with a cleaner way to
1345                          * enabling COOKIE-ECHO + DATA bundling during
1346                          * multihoming stale cookie scenarios, the following
1347                          * command plays with asoc->peer.retran_path to
1348                          * avoid the problem of sending the COOKIE-ECHO and
1349                          * DATA in different paths, which could result
1350                          * in the association being ABORTed if the DATA chunk
1351                          * is processed first by the server.  Checking the
1352                          * init error counter simply causes this command
1353                          * to be executed only during failed attempts of
1354                          * association establishment.
1355                          */
1356                         if ((asoc->peer.retran_path !=
1357                              asoc->peer.primary_path) &&
1358                             (asoc->init_err_counter > 0)) {
1359                                 sctp_add_cmd_sf(commands,
1360                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1361                                                 SCTP_NULL());
1362                         }
1363
1364                         break;
1365
1366                 case SCTP_CMD_GEN_SHUTDOWN:
1367                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1368                          * Reset error counts.
1369                          */
1370                         asoc->overall_error_count = 0;
1371
1372                         /* Generate a SHUTDOWN chunk.  */
1373                         new_obj = sctp_make_shutdown(asoc, chunk);
1374                         if (!new_obj)
1375                                 goto nomem;
1376                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1377                                         SCTP_CHUNK(new_obj));
1378                         break;
1379
1380                 case SCTP_CMD_CHUNK_ULP:
1381                         /* Send a chunk to the sockets layer.  */
1382                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1383                                           "chunk_up:", cmd->obj.ptr,
1384                                           "ulpq:", &asoc->ulpq);
1385                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1386                                             GFP_ATOMIC);
1387                         break;
1388
1389                 case SCTP_CMD_EVENT_ULP:
1390                         /* Send a notification to the sockets layer.  */
1391                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1392                                           "event_up:",cmd->obj.ptr,
1393                                           "ulpq:",&asoc->ulpq);
1394                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1395                         break;
1396
1397                 case SCTP_CMD_REPLY:
1398                         /* If an caller has not already corked, do cork. */
1399                         if (!asoc->outqueue.cork) {
1400                                 sctp_outq_cork(&asoc->outqueue);
1401                                 local_cork = 1;
1402                         }
1403                         /* Send a chunk to our peer.  */
1404                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1405                         break;
1406
1407                 case SCTP_CMD_SEND_PKT:
1408                         /* Send a full packet to our peer.  */
1409                         packet = cmd->obj.ptr;
1410                         sctp_packet_transmit(packet);
1411                         sctp_ootb_pkt_free(packet);
1412                         break;
1413
1414                 case SCTP_CMD_T1_RETRAN:
1415                         /* Mark a transport for retransmission.  */
1416                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1417                                         SCTP_RTXR_T1_RTX);
1418                         break;
1419
1420                 case SCTP_CMD_RETRAN:
1421                         /* Mark a transport for retransmission.  */
1422                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1423                                         SCTP_RTXR_T3_RTX);
1424                         break;
1425
1426                 case SCTP_CMD_ECN_CE:
1427                         /* Do delayed CE processing.   */
1428                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1429                         break;
1430
1431                 case SCTP_CMD_ECN_ECNE:
1432                         /* Do delayed ECNE processing. */
1433                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1434                                                         chunk);
1435                         if (new_obj)
1436                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1437                                                 SCTP_CHUNK(new_obj));
1438                         break;
1439
1440                 case SCTP_CMD_ECN_CWR:
1441                         /* Do delayed CWR processing.  */
1442                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1443                         break;
1444
1445                 case SCTP_CMD_SETUP_T2:
1446                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1447                         break;
1448
1449                 case SCTP_CMD_TIMER_START_ONCE:
1450                         timer = &asoc->timers[cmd->obj.to];
1451
1452                         if (timer_pending(timer))
1453                                 break;
1454                         /* fall through */
1455
1456                 case SCTP_CMD_TIMER_START:
1457                         timer = &asoc->timers[cmd->obj.to];
1458                         timeout = asoc->timeouts[cmd->obj.to];
1459                         BUG_ON(!timeout);
1460
1461                         timer->expires = jiffies + timeout;
1462                         sctp_association_hold(asoc);
1463                         add_timer(timer);
1464                         break;
1465
1466                 case SCTP_CMD_TIMER_RESTART:
1467                         timer = &asoc->timers[cmd->obj.to];
1468                         timeout = asoc->timeouts[cmd->obj.to];
1469                         if (!mod_timer(timer, jiffies + timeout))
1470                                 sctp_association_hold(asoc);
1471                         break;
1472
1473                 case SCTP_CMD_TIMER_STOP:
1474                         timer = &asoc->timers[cmd->obj.to];
1475                         if (timer_pending(timer) && del_timer(timer))
1476                                 sctp_association_put(asoc);
1477                         break;
1478
1479                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1480                         chunk = cmd->obj.ptr;
1481                         t = sctp_assoc_choose_alter_transport(asoc,
1482                                                 asoc->init_last_sent_to);
1483                         asoc->init_last_sent_to = t;
1484                         chunk->transport = t;
1485                         t->init_sent_count++;
1486                         /* Set the new transport as primary */
1487                         sctp_assoc_set_primary(asoc, t);
1488                         break;
1489
1490                 case SCTP_CMD_INIT_RESTART:
1491                         /* Do the needed accounting and updates
1492                          * associated with restarting an initialization
1493                          * timer. Only multiply the timeout by two if
1494                          * all transports have been tried at the current
1495                          * timeout.
1496                          */
1497                         sctp_cmd_t1_timer_update(asoc,
1498                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1499                                                 "INIT");
1500
1501                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1502                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1503                         break;
1504
1505                 case SCTP_CMD_COOKIEECHO_RESTART:
1506                         /* Do the needed accounting and updates
1507                          * associated with restarting an initialization
1508                          * timer. Only multiply the timeout by two if
1509                          * all transports have been tried at the current
1510                          * timeout.
1511                          */
1512                         sctp_cmd_t1_timer_update(asoc,
1513                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1514                                                 "COOKIE");
1515
1516                         /* If we've sent any data bundled with
1517                          * COOKIE-ECHO we need to resend.
1518                          */
1519                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1520                                         transports) {
1521                                 sctp_retransmit_mark(&asoc->outqueue, t,
1522                                             SCTP_RTXR_T1_RTX);
1523                         }
1524
1525                         sctp_add_cmd_sf(commands,
1526                                         SCTP_CMD_TIMER_RESTART,
1527                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1528                         break;
1529
1530                 case SCTP_CMD_INIT_FAILED:
1531                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1532                         break;
1533
1534                 case SCTP_CMD_ASSOC_FAILED:
1535                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1536                                               subtype, chunk, cmd->obj.err);
1537                         break;
1538
1539                 case SCTP_CMD_INIT_COUNTER_INC:
1540                         asoc->init_err_counter++;
1541                         break;
1542
1543                 case SCTP_CMD_INIT_COUNTER_RESET:
1544                         asoc->init_err_counter = 0;
1545                         asoc->init_cycle = 0;
1546                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1547                                             transports) {
1548                                 t->init_sent_count = 0;
1549                         }
1550                         break;
1551
1552                 case SCTP_CMD_REPORT_DUP:
1553                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1554                                              cmd->obj.u32);
1555                         break;
1556
1557                 case SCTP_CMD_REPORT_BAD_TAG:
1558                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1559                         break;
1560
1561                 case SCTP_CMD_STRIKE:
1562                         /* Mark one strike against a transport.  */
1563                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1564                                                     0);
1565                         break;
1566
1567                 case SCTP_CMD_TRANSPORT_IDLE:
1568                         t = cmd->obj.transport;
1569                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1570                         break;
1571
1572                 case SCTP_CMD_TRANSPORT_HB_SENT:
1573                         t = cmd->obj.transport;
1574                         sctp_do_8_2_transport_strike(asoc, t, 1);
1575                         t->hb_sent = 1;
1576                         break;
1577
1578                 case SCTP_CMD_TRANSPORT_ON:
1579                         t = cmd->obj.transport;
1580                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1581                         break;
1582
1583                 case SCTP_CMD_HB_TIMERS_START:
1584                         sctp_cmd_hb_timers_start(commands, asoc);
1585                         break;
1586
1587                 case SCTP_CMD_HB_TIMER_UPDATE:
1588                         t = cmd->obj.transport;
1589                         sctp_cmd_hb_timer_update(commands, t);
1590                         break;
1591
1592                 case SCTP_CMD_HB_TIMERS_STOP:
1593                         sctp_cmd_hb_timers_stop(commands, asoc);
1594                         break;
1595
1596                 case SCTP_CMD_REPORT_ERROR:
1597                         error = cmd->obj.error;
1598                         break;
1599
1600                 case SCTP_CMD_PROCESS_CTSN:
1601                         /* Dummy up a SACK for processing. */
1602                         sackh.cum_tsn_ack = cmd->obj.be32;
1603                         sackh.a_rwnd = asoc->peer.rwnd +
1604                                         asoc->outqueue.outstanding_bytes;
1605                         sackh.num_gap_ack_blocks = 0;
1606                         sackh.num_dup_tsns = 0;
1607                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1608                                         SCTP_SACKH(&sackh));
1609                         break;
1610
1611                 case SCTP_CMD_DISCARD_PACKET:
1612                         /* We need to discard the whole packet.
1613                          * Uncork the queue since there might be
1614                          * responses pending
1615                          */
1616                         chunk->pdiscard = 1;
1617                         if (asoc) {
1618                                 sctp_outq_uncork(&asoc->outqueue);
1619                                 local_cork = 0;
1620                         }
1621                         break;
1622
1623                 case SCTP_CMD_RTO_PENDING:
1624                         t = cmd->obj.transport;
1625                         t->rto_pending = 1;
1626                         break;
1627
1628                 case SCTP_CMD_PART_DELIVER:
1629                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1630                                                    GFP_ATOMIC);
1631                         break;
1632
1633                 case SCTP_CMD_RENEGE:
1634                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1635                                          GFP_ATOMIC);
1636                         break;
1637
1638                 case SCTP_CMD_SETUP_T4:
1639                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1640                         break;
1641
1642                 case SCTP_CMD_PROCESS_OPERR:
1643                         sctp_cmd_process_operr(commands, asoc, chunk);
1644                         break;
1645                 case SCTP_CMD_CLEAR_INIT_TAG:
1646                         asoc->peer.i.init_tag = 0;
1647                         break;
1648                 case SCTP_CMD_DEL_NON_PRIMARY:
1649                         sctp_cmd_del_non_primary(asoc);
1650                         break;
1651                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1652                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1653                         break;
1654                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1655                         t = asoc->peer.retran_path;
1656                         asoc->peer.retran_path = asoc->peer.primary_path;
1657                         error = sctp_outq_uncork(&asoc->outqueue);
1658                         local_cork = 0;
1659                         asoc->peer.retran_path = t;
1660                         break;
1661                 case SCTP_CMD_SET_SK_ERR:
1662                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1663                         break;
1664                 case SCTP_CMD_ASSOC_CHANGE:
1665                         sctp_cmd_assoc_change(commands, asoc,
1666                                               cmd->obj.u8);
1667                         break;
1668                 case SCTP_CMD_ADAPTATION_IND:
1669                         sctp_cmd_adaptation_ind(commands, asoc);
1670                         break;
1671
1672                 case SCTP_CMD_ASSOC_SHKEY:
1673                         error = sctp_auth_asoc_init_active_key(asoc,
1674                                                 GFP_ATOMIC);
1675                         break;
1676                 case SCTP_CMD_UPDATE_INITTAG:
1677                         asoc->peer.i.init_tag = cmd->obj.u32;
1678                         break;
1679                 case SCTP_CMD_SEND_MSG:
1680                         if (!asoc->outqueue.cork) {
1681                                 sctp_outq_cork(&asoc->outqueue);
1682                                 local_cork = 1;
1683                         }
1684                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1685                         break;
1686                 case SCTP_CMD_SEND_NEXT_ASCONF:
1687                         sctp_cmd_send_asconf(asoc);
1688                         break;
1689                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1690                         sctp_asconf_queue_teardown(asoc);
1691                         break;
1692
1693                 case SCTP_CMD_SET_ASOC:
1694                         asoc = cmd->obj.asoc;
1695                         break;
1696
1697                 default:
1698                         pr_warn("Impossible command: %u, %p\n",
1699                                 cmd->verb, cmd->obj.ptr);
1700                         break;
1701                 }
1702
1703                 if (error)
1704                         break;
1705         }
1706
1707 out:
1708         /* If this is in response to a received chunk, wait until
1709          * we are done with the packet to open the queue so that we don't
1710          * send multiple packets in response to a single request.
1711          */
1712         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1713                 if (chunk->end_of_packet || chunk->singleton)
1714                         error = sctp_outq_uncork(&asoc->outqueue);
1715         } else if (local_cork)
1716                 error = sctp_outq_uncork(&asoc->outqueue);
1717         return error;
1718 nomem:
1719         error = -ENOMEM;
1720         goto out;
1721 }
1722