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sm.h
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1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * These are definitions needed by the state machine.
10  *
11  * This SCTP implementation is free software;
12  * you can redistribute it and/or modify it under the terms of
13  * the GNU General Public License as published by
14  * the Free Software Foundation; either version 2, or (at your option)
15  * any later version.
16  *
17  * This SCTP implementation is distributed in the hope that it
18  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
19  * ************************
20  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
21  * See the GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with GNU CC; see the file COPYING. If not, write to
25  * the Free Software Foundation, 59 Temple Place - Suite 330,
26  * Boston, MA 02111-1307, USA.
27  *
28  * Please send any bug reports or fixes you make to the
29  * email addresses:
30  * lksctp developers <[email protected]>
31  *
32  * Or submit a bug report through the following website:
33  * http://www.sf.net/projects/lksctp
34  *
35  * Written or modified by:
36  * La Monte H.P. Yarroll <[email protected]>
37  * Karl Knutson <[email protected]>
38  * Xingang Guo <[email protected]>
39  * Jon Grimm <[email protected]>
40  * Dajiang Zhang <[email protected]>
41  * Sridhar Samudrala <[email protected]>
42  * Daisy Chang <[email protected]>
43  * Ardelle Fan <[email protected]>
44  * Kevin Gao <[email protected]>
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 #include <linux/types.h>
51 #include <linux/compiler.h>
52 #include <linux/slab.h>
53 #include <linux/in.h>
54 #include <net/sctp/command.h>
55 #include <net/sctp/sctp.h>
56 
57 #ifndef __sctp_sm_h__
58 #define __sctp_sm_h__
59 
60 /*
61  * Possible values for the disposition are:
62  */
63 typedef enum {
64  SCTP_DISPOSITION_DISCARD, /* No further processing. */
65  SCTP_DISPOSITION_CONSUME, /* Process return values normally. */
66  SCTP_DISPOSITION_NOMEM, /* We ran out of memory--recover. */
67  SCTP_DISPOSITION_DELETE_TCB, /* Close the association. */
68  SCTP_DISPOSITION_ABORT, /* Close the association NOW. */
69  SCTP_DISPOSITION_VIOLATION, /* The peer is misbehaving. */
70  SCTP_DISPOSITION_NOT_IMPL, /* This entry is not implemented. */
71  SCTP_DISPOSITION_ERROR, /* This is plain old user error. */
72  SCTP_DISPOSITION_BUG, /* This is a bug. */
74 
75 typedef struct {
76  int name;
77  int action;
79 
81  const struct sctp_endpoint *,
82  const struct sctp_association *,
83  const sctp_subtype_t type,
84  void *arg,
85  sctp_cmd_seq_t *);
86 typedef void (sctp_timer_event_t) (unsigned long);
87 typedef struct {
89  const char *name;
91 
92 /* A naming convention of "sctp_sf_xxx" applies to all the state functions
93  * currently in use.
94  */
95 
96 /* Prototypes for generic state functions. */
99 
100 /* Prototypes for gener timer state functions. */
102 
103 /* Prototypes for chunk state functions. */
149 
150 /* Prototypes for primitive event state functions. */
167 
168 /* Prototypes for other event state functions. */
174 
175 /* Prototypes for timeout event state functions. */
179 
180 /* Prototypes for utility support functions. */
183  sctp_event_t,
184  sctp_state_t,
186 int sctp_chunk_iif(const struct sctp_chunk *);
187 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *,
188  struct sctp_chunk *,
189  gfp_t gfp);
191 void sctp_populate_tie_tags(__u8 *cookie, __u32 curTag, __u32 hisTag);
192 
193 /* Prototypes for chunk-building functions. */
194 struct sctp_chunk *sctp_make_init(const struct sctp_association *,
195  const struct sctp_bind_addr *,
196  gfp_t gfp, int vparam_len);
197 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *,
198  const struct sctp_chunk *,
199  const gfp_t gfp,
200  const int unkparam_len);
201 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *,
202  const struct sctp_chunk *);
203 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *,
204  const struct sctp_chunk *);
205 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *,
206  const __u32 lowest_tsn,
207  const struct sctp_chunk *);
209  const struct sctp_sndrcvinfo *sinfo,
210  int len, const __u8 flags,
211  __u16 ssn);
212 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *,
213  const __u32);
214 struct sctp_chunk *sctp_make_sack(const struct sctp_association *);
215 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
216  const struct sctp_chunk *chunk);
218  const struct sctp_chunk *);
220  const struct sctp_chunk *);
221 void sctp_init_cause(struct sctp_chunk *, __be16 cause, size_t);
222 struct sctp_chunk *sctp_make_abort(const struct sctp_association *,
223  const struct sctp_chunk *,
224  const size_t hint);
226  const struct sctp_chunk *,
227  __u32 tsn);
228 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *,
229  const struct msghdr *, size_t msg_len);
231  const struct sctp_chunk *,
232  const __u8 *,
233  const size_t );
235  const struct sctp_chunk *,
236  struct sctp_paramhdr *);
237 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *,
238  const struct sctp_transport *);
240  const struct sctp_chunk *,
241  const void *payload,
242  const size_t paylen);
243 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *,
244  const struct sctp_chunk *chunk,
245  __be16 cause_code,
246  const void *payload,
247  size_t paylen,
248  size_t reserve_tail);
249 
251  union sctp_addr *,
252  struct sockaddr *,
253  int, __be16);
255  union sctp_addr *addr);
256 int sctp_verify_asconf(const struct sctp_association *asoc,
257  struct sctp_paramhdr *param_hdr, void *chunk_end,
258  struct sctp_paramhdr **errp);
260  struct sctp_chunk *asconf);
262  struct sctp_chunk *asconf_ack);
263 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
264  __u32 new_cum_tsn, size_t nstreams,
265  struct sctp_fwdtsn_skip *skiplist);
266 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc);
267 
268 void sctp_chunk_assign_tsn(struct sctp_chunk *);
269 void sctp_chunk_assign_ssn(struct sctp_chunk *);
270 
271 /* Prototypes for statetable processing. */
272 
275  struct sctp_endpoint *,
276  struct sctp_association *asoc,
277  void *event_arg,
278  gfp_t gfp);
279 
280 /* 2nd level prototypes */
281 void sctp_generate_t3_rtx_event(unsigned long peer);
282 void sctp_generate_heartbeat_event(unsigned long peer);
283 void sctp_generate_proto_unreach_event(unsigned long peer);
284 
285 void sctp_ootb_pkt_free(struct sctp_packet *);
286 
287 struct sctp_association *sctp_unpack_cookie(const struct sctp_endpoint *,
288  const struct sctp_association *,
289  struct sctp_chunk *,
290  gfp_t gfp, int *err,
291  struct sctp_chunk **err_chk_p);
293  struct sockaddr_storage*, int);
294 
295 /* 3rd level prototypes */
296 __u32 sctp_generate_tag(const struct sctp_endpoint *);
297 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
298 
299 /* Extern declarations for major data structures. */
301 
302 
303 /* Get the size of a DATA chunk payload. */
304 static inline __u16 sctp_data_size(struct sctp_chunk *chunk)
305 {
306  __u16 size;
307 
308  size = ntohs(chunk->chunk_hdr->length);
309  size -= sizeof(sctp_data_chunk_t);
310 
311  return size;
312 }
313 
314 /* Compare two TSNs */
315 
316 /* RFC 1982 - Serial Number Arithmetic
317  *
318  * 2. Comparison
319  * Then, s1 is said to be equal to s2 if and only if i1 is equal to i2,
320  * in all other cases, s1 is not equal to s2.
321  *
322  * s1 is said to be less than s2 if, and only if, s1 is not equal to s2,
323  * and
324  *
325  * (i1 < i2 and i2 - i1 < 2^(SERIAL_BITS - 1)) or
326  * (i1 > i2 and i1 - i2 > 2^(SERIAL_BITS - 1))
327  *
328  * s1 is said to be greater than s2 if, and only if, s1 is not equal to
329  * s2, and
330  *
331  * (i1 < i2 and i2 - i1 > 2^(SERIAL_BITS - 1)) or
332  * (i1 > i2 and i1 - i2 < 2^(SERIAL_BITS - 1))
333  */
334 
335 /*
336  * RFC 2960
337  * 1.6 Serial Number Arithmetic
338  *
339  * Comparisons and arithmetic on TSNs in this document SHOULD use Serial
340  * Number Arithmetic as defined in [RFC1982] where SERIAL_BITS = 32.
341  */
342 
343 enum {
344  TSN_SIGN_BIT = (1<<31)
345 };
346 
347 static inline int TSN_lt(__u32 s, __u32 t)
348 {
349  return ((s) - (t)) & TSN_SIGN_BIT;
350 }
351 
352 static inline int TSN_lte(__u32 s, __u32 t)
353 {
354  return ((s) == (t)) || (((s) - (t)) & TSN_SIGN_BIT);
355 }
356 
357 /* Compare two SSNs */
358 
359 /*
360  * RFC 2960
361  * 1.6 Serial Number Arithmetic
362  *
363  * Comparisons and arithmetic on Stream Sequence Numbers in this document
364  * SHOULD use Serial Number Arithmetic as defined in [RFC1982] where
365  * SERIAL_BITS = 16.
366  */
367 enum {
368  SSN_SIGN_BIT = (1<<15)
369 };
370 
371 static inline int SSN_lt(__u16 s, __u16 t)
372 {
373  return ((s) - (t)) & SSN_SIGN_BIT;
374 }
375 
376 static inline int SSN_lte(__u16 s, __u16 t)
377 {
378  return ((s) == (t)) || (((s) - (t)) & SSN_SIGN_BIT);
379 }
380 
381 /*
382  * ADDIP 3.1.1
383  * The valid range of Serial Number is from 0 to 4294967295 (2**32 - 1). Serial
384  * Numbers wrap back to 0 after reaching 4294967295.
385  */
386 enum {
388 };
389 
390 static inline int ADDIP_SERIAL_gte(__u16 s, __u16 t)
391 {
392  return ((s) == (t)) || (((t) - (s)) & ADDIP_SERIAL_SIGN_BIT);
393 }
394 
395 /* Check VTAG of the packet matches the sender's own tag. */
396 static inline int
397 sctp_vtag_verify(const struct sctp_chunk *chunk,
398  const struct sctp_association *asoc)
399 {
400  /* RFC 2960 Sec 8.5 When receiving an SCTP packet, the endpoint
401  * MUST ensure that the value in the Verification Tag field of
402  * the received SCTP packet matches its own Tag. If the received
403  * Verification Tag value does not match the receiver's own
404  * tag value, the receiver shall silently discard the packet...
405  */
406  if (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)
407  return 1;
408 
409  return 0;
410 }
411 
412 /* Check VTAG of the packet matches the sender's own tag and the T bit is
413  * not set, OR its peer's tag and the T bit is set in the Chunk Flags.
414  */
415 static inline int
416 sctp_vtag_verify_either(const struct sctp_chunk *chunk,
417  const struct sctp_association *asoc)
418 {
419  /* RFC 2960 Section 8.5.1, sctpimpguide Section 2.41
420  *
421  * B) The receiver of a ABORT MUST accept the packet
422  * if the Verification Tag field of the packet matches its own tag
423  * and the T bit is not set
424  * OR
425  * it is set to its peer's tag and the T bit is set in the Chunk
426  * Flags.
427  * Otherwise, the receiver MUST silently discard the packet
428  * and take no further action.
429  *
430  * C) The receiver of a SHUTDOWN COMPLETE shall accept the packet
431  * if the Verification Tag field of the packet matches its own tag
432  * and the T bit is not set
433  * OR
434  * it is set to its peer's tag and the T bit is set in the Chunk
435  * Flags.
436  * Otherwise, the receiver MUST silently discard the packet
437  * and take no further action. An endpoint MUST ignore the
438  * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
439  */
440  if ((!sctp_test_T_bit(chunk) &&
441  (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)) ||
442  (sctp_test_T_bit(chunk) && asoc->c.peer_vtag &&
443  (ntohl(chunk->sctp_hdr->vtag) == asoc->c.peer_vtag))) {
444  return 1;
445  }
446 
447  return 0;
448 }
449 
450 #endif /* __sctp_sm_h__ */