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 <lksctp-developers@lists.sourceforge.net>
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 <piggy@acm.org>
37 * Karl Knutson <karl@athena.chicago.il.us>
38 * Xingang Guo <xingang.guo@intel.com>
39 * Jon Grimm <jgrimm@us.ibm.com>
40 * Dajiang Zhang <dajiang.zhang@nokia.com>
41 * Sridhar Samudrala <sri@us.ibm.com>
42 * Daisy Chang <daisyc@us.ibm.com>
43 * Ardelle Fan <ardelle.fan@intel.com>
44 * Kevin Gao <kevin.gao@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 #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. */
73 } sctp_disposition_t;
74
75 typedef struct {
76 int name;
77 int action;
78 } sctp_sm_command_t;
79
80 typedef sctp_disposition_t (sctp_state_fn_t) (const struct sctp_endpoint *,
81 const struct sctp_association *,
82 const sctp_subtype_t type,
83 void *arg,
84 sctp_cmd_seq_t *);
85 typedef void (sctp_timer_event_t) (unsigned long);
86 typedef struct {
87 sctp_state_fn_t *fn;
88 const char *name;
89 } sctp_sm_table_entry_t;
90
91 /* A naming convention of "sctp_sf_xxx" applies to all the state functions
92 * currently in use.
93 */
94
95 /* Prototypes for generic state functions. */
96 sctp_state_fn_t sctp_sf_not_impl;
97 sctp_state_fn_t sctp_sf_bug;
98
99 /* Prototypes for gener timer state functions. */
100 sctp_state_fn_t sctp_sf_timer_ignore;
101
102 /* Prototypes for chunk state functions. */
103 sctp_state_fn_t sctp_sf_do_9_1_abort;
104 sctp_state_fn_t sctp_sf_cookie_wait_abort;
105 sctp_state_fn_t sctp_sf_cookie_echoed_abort;
106 sctp_state_fn_t sctp_sf_shutdown_pending_abort;
107 sctp_state_fn_t sctp_sf_shutdown_sent_abort;
108 sctp_state_fn_t sctp_sf_shutdown_ack_sent_abort;
109 sctp_state_fn_t sctp_sf_do_5_1B_init;
110 sctp_state_fn_t sctp_sf_do_5_1C_ack;
111 sctp_state_fn_t sctp_sf_do_5_1D_ce;
112 sctp_state_fn_t sctp_sf_do_5_1E_ca;
113 sctp_state_fn_t sctp_sf_do_4_C;
114 sctp_state_fn_t sctp_sf_eat_data_6_2;
115 sctp_state_fn_t sctp_sf_eat_data_fast_4_4;
116 sctp_state_fn_t sctp_sf_eat_sack_6_2;
117 sctp_state_fn_t sctp_sf_operr_notify;
118 sctp_state_fn_t sctp_sf_t1_init_timer_expire;
119 sctp_state_fn_t sctp_sf_t1_cookie_timer_expire;
120 sctp_state_fn_t sctp_sf_t2_timer_expire;
121 sctp_state_fn_t sctp_sf_t4_timer_expire;
122 sctp_state_fn_t sctp_sf_t5_timer_expire;
123 sctp_state_fn_t sctp_sf_sendbeat_8_3;
124 sctp_state_fn_t sctp_sf_beat_8_3;
125 sctp_state_fn_t sctp_sf_backbeat_8_3;
126 sctp_state_fn_t sctp_sf_do_9_2_final;
127 sctp_state_fn_t sctp_sf_do_9_2_shutdown;
128 sctp_state_fn_t sctp_sf_do_9_2_shut_ctsn;
129 sctp_state_fn_t sctp_sf_do_ecn_cwr;
130 sctp_state_fn_t sctp_sf_do_ecne;
131 sctp_state_fn_t sctp_sf_ootb;
132 sctp_state_fn_t sctp_sf_pdiscard;
133 sctp_state_fn_t sctp_sf_violation;
134 sctp_state_fn_t sctp_sf_discard_chunk;
135 sctp_state_fn_t sctp_sf_do_5_2_1_siminit;
136 sctp_state_fn_t sctp_sf_do_5_2_2_dupinit;
137 sctp_state_fn_t sctp_sf_do_5_2_3_initack;
138 sctp_state_fn_t sctp_sf_do_5_2_4_dupcook;
139 sctp_state_fn_t sctp_sf_unk_chunk;
140 sctp_state_fn_t sctp_sf_do_8_5_1_E_sa;
141 sctp_state_fn_t sctp_sf_cookie_echoed_err;
142 sctp_state_fn_t sctp_sf_do_asconf;
143 sctp_state_fn_t sctp_sf_do_asconf_ack;
144 sctp_state_fn_t sctp_sf_do_9_2_reshutack;
145 sctp_state_fn_t sctp_sf_eat_fwd_tsn;
146 sctp_state_fn_t sctp_sf_eat_fwd_tsn_fast;
147 sctp_state_fn_t sctp_sf_eat_auth;
148
149 /* Prototypes for primitive event state functions. */
150 sctp_state_fn_t sctp_sf_do_prm_asoc;
151 sctp_state_fn_t sctp_sf_do_prm_send;
152 sctp_state_fn_t sctp_sf_do_9_2_prm_shutdown;
153 sctp_state_fn_t sctp_sf_cookie_wait_prm_shutdown;
154 sctp_state_fn_t sctp_sf_cookie_echoed_prm_shutdown;
155 sctp_state_fn_t sctp_sf_do_9_1_prm_abort;
156 sctp_state_fn_t sctp_sf_cookie_wait_prm_abort;
157 sctp_state_fn_t sctp_sf_cookie_echoed_prm_abort;
158 sctp_state_fn_t sctp_sf_shutdown_pending_prm_abort;
159 sctp_state_fn_t sctp_sf_shutdown_sent_prm_abort;
160 sctp_state_fn_t sctp_sf_shutdown_ack_sent_prm_abort;
161 sctp_state_fn_t sctp_sf_error_closed;
162 sctp_state_fn_t sctp_sf_error_shutdown;
163 sctp_state_fn_t sctp_sf_ignore_primitive;
164 sctp_state_fn_t sctp_sf_do_prm_requestheartbeat;
165 sctp_state_fn_t sctp_sf_do_prm_asconf;
166
167 /* Prototypes for other event state functions. */
168 sctp_state_fn_t sctp_sf_do_no_pending_tsn;
169 sctp_state_fn_t sctp_sf_do_9_2_start_shutdown;
170 sctp_state_fn_t sctp_sf_do_9_2_shutdown_ack;
171 sctp_state_fn_t sctp_sf_ignore_other;
172 sctp_state_fn_t sctp_sf_cookie_wait_icmp_abort;
173
174 /* Prototypes for timeout event state functions. */
175 sctp_state_fn_t sctp_sf_do_6_3_3_rtx;
176 sctp_state_fn_t sctp_sf_do_6_2_sack;
177 sctp_state_fn_t sctp_sf_autoclose_timer_expire;
178
179 /* Prototypes for utility support functions. */
180 __u8 sctp_get_chunk_type(struct sctp_chunk *chunk);
181 const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t,
182 sctp_state_t,
183 sctp_subtype_t);
184 int sctp_chunk_iif(const struct sctp_chunk *);
185 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *,
186 struct sctp_chunk *,
187 gfp_t gfp);
188 __u32 sctp_generate_verification_tag(void);
189 void sctp_populate_tie_tags(__u8 *cookie, __u32 curTag, __u32 hisTag);
190
191 /* Prototypes for chunk-building functions. */
192 struct sctp_chunk *sctp_make_init(const struct sctp_association *,
193 const struct sctp_bind_addr *,
194 gfp_t gfp, int vparam_len);
195 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *,
196 const struct sctp_chunk *,
197 const gfp_t gfp,
198 const int unkparam_len);
199 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *,
200 const struct sctp_chunk *);
201 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *,
202 const struct sctp_chunk *);
203 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *,
204 const __u32 lowest_tsn,
205 const struct sctp_chunk *);
206 struct sctp_chunk * sctp_make_datafrag_empty(struct sctp_association *,
207 const struct sctp_sndrcvinfo *sinfo,
208 int len, const __u8 flags,
209 __u16 ssn);
210 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *,
211 const __u32);
212 struct sctp_chunk *sctp_make_sack(const struct sctp_association *);
213 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
214 const struct sctp_chunk *chunk);
215 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
216 const struct sctp_chunk *);
217 struct sctp_chunk *sctp_make_shutdown_complete(const struct sctp_association *,
218 const struct sctp_chunk *);
219 void sctp_init_cause(struct sctp_chunk *, __be16 cause, size_t);
220 struct sctp_chunk *sctp_make_abort(const struct sctp_association *,
221 const struct sctp_chunk *,
222 const size_t hint);
223 struct sctp_chunk *sctp_make_abort_no_data(const struct sctp_association *,
224 const struct sctp_chunk *,
225 __u32 tsn);
226 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *,
227 const struct msghdr *, size_t msg_len);
228 struct sctp_chunk *sctp_make_abort_violation(const struct sctp_association *,
229 const struct sctp_chunk *,
230 const __u8 *,
231 const size_t );
232 struct sctp_chunk *sctp_make_violation_paramlen(const struct sctp_association *,
233 const struct sctp_chunk *,
234 struct sctp_paramhdr *);
235 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *,
236 const struct sctp_transport *);
237 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *,
238 const struct sctp_chunk *,
239 const void *payload,
240 const size_t paylen);
241 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *,
242 const struct sctp_chunk *chunk,
243 __be16 cause_code,
244 const void *payload,
245 size_t paylen,
246 size_t reserve_tail);
247
248 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *,
249 union sctp_addr *,
250 struct sockaddr *,
251 int, __be16);
252 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
253 union sctp_addr *addr);
254 int sctp_verify_asconf(const struct sctp_association *asoc,
255 struct sctp_paramhdr *param_hdr, void *chunk_end,
256 struct sctp_paramhdr **errp);
257 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
258 struct sctp_chunk *asconf);
259 int sctp_process_asconf_ack(struct sctp_association *asoc,
260 struct sctp_chunk *asconf_ack);
261 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
262 __u32 new_cum_tsn, size_t nstreams,
263 struct sctp_fwdtsn_skip *skiplist);
264 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc);
265
266 void sctp_chunk_assign_tsn(struct sctp_chunk *);
267 void sctp_chunk_assign_ssn(struct sctp_chunk *);
268
269 /* Prototypes for statetable processing. */
270
271 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
272 sctp_state_t state,
273 struct sctp_endpoint *,
274 struct sctp_association *asoc,
275 void *event_arg,
276 gfp_t gfp);
277
278 /* 2nd level prototypes */
279 void sctp_generate_t3_rtx_event(unsigned long peer);
280 void sctp_generate_heartbeat_event(unsigned long peer);
281 void sctp_generate_proto_unreach_event(unsigned long peer);
282
283 void sctp_ootb_pkt_free(struct sctp_packet *);
284
285 struct sctp_association *sctp_unpack_cookie(const struct sctp_endpoint *,
286 const struct sctp_association *,
287 struct sctp_chunk *,
288 gfp_t gfp, int *err,
289 struct sctp_chunk **err_chk_p);
290 int sctp_addip_addr_config(struct sctp_association *, sctp_param_t,
291 struct sockaddr_storage*, int);
292
293 /* 3rd level prototypes */
294 __u32 sctp_generate_tag(const struct sctp_endpoint *);
295 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
296
297 /* Extern declarations for major data structures. */
298 extern sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES];
299
300
301 /* Get the size of a DATA chunk payload. */
sctp_data_size(struct sctp_chunk * chunk)302 static inline __u16 sctp_data_size(struct sctp_chunk *chunk)
303 {
304 __u16 size;
305
306 size = ntohs(chunk->chunk_hdr->length);
307 size -= sizeof(sctp_data_chunk_t);
308
309 return size;
310 }
311
312 /* Compare two TSNs */
313
314 /* RFC 1982 - Serial Number Arithmetic
315 *
316 * 2. Comparison
317 * Then, s1 is said to be equal to s2 if and only if i1 is equal to i2,
318 * in all other cases, s1 is not equal to s2.
319 *
320 * s1 is said to be less than s2 if, and only if, s1 is not equal to s2,
321 * and
322 *
323 * (i1 < i2 and i2 - i1 < 2^(SERIAL_BITS - 1)) or
324 * (i1 > i2 and i1 - i2 > 2^(SERIAL_BITS - 1))
325 *
326 * s1 is said to be greater than s2 if, and only if, s1 is not equal to
327 * s2, and
328 *
329 * (i1 < i2 and i2 - i1 > 2^(SERIAL_BITS - 1)) or
330 * (i1 > i2 and i1 - i2 < 2^(SERIAL_BITS - 1))
331 */
332
333 /*
334 * RFC 2960
335 * 1.6 Serial Number Arithmetic
336 *
337 * Comparisons and arithmetic on TSNs in this document SHOULD use Serial
338 * Number Arithmetic as defined in [RFC1982] where SERIAL_BITS = 32.
339 */
340
341 enum {
342 TSN_SIGN_BIT = (1<<31)
343 };
344
TSN_lt(__u32 s,__u32 t)345 static inline int TSN_lt(__u32 s, __u32 t)
346 {
347 return ((s) - (t)) & TSN_SIGN_BIT;
348 }
349
TSN_lte(__u32 s,__u32 t)350 static inline int TSN_lte(__u32 s, __u32 t)
351 {
352 return ((s) == (t)) || (((s) - (t)) & TSN_SIGN_BIT);
353 }
354
355 /* Compare two SSNs */
356
357 /*
358 * RFC 2960
359 * 1.6 Serial Number Arithmetic
360 *
361 * Comparisons and arithmetic on Stream Sequence Numbers in this document
362 * SHOULD use Serial Number Arithmetic as defined in [RFC1982] where
363 * SERIAL_BITS = 16.
364 */
365 enum {
366 SSN_SIGN_BIT = (1<<15)
367 };
368
SSN_lt(__u16 s,__u16 t)369 static inline int SSN_lt(__u16 s, __u16 t)
370 {
371 return ((s) - (t)) & SSN_SIGN_BIT;
372 }
373
SSN_lte(__u16 s,__u16 t)374 static inline int SSN_lte(__u16 s, __u16 t)
375 {
376 return ((s) == (t)) || (((s) - (t)) & SSN_SIGN_BIT);
377 }
378
379 /*
380 * ADDIP 3.1.1
381 * The valid range of Serial Number is from 0 to 4294967295 (2**32 - 1). Serial
382 * Numbers wrap back to 0 after reaching 4294967295.
383 */
384 enum {
385 ADDIP_SERIAL_SIGN_BIT = (1<<31)
386 };
387
ADDIP_SERIAL_gte(__u16 s,__u16 t)388 static inline int ADDIP_SERIAL_gte(__u16 s, __u16 t)
389 {
390 return ((s) == (t)) || (((t) - (s)) & ADDIP_SERIAL_SIGN_BIT);
391 }
392
393 /* Check VTAG of the packet matches the sender's own tag. */
394 static inline int
sctp_vtag_verify(const struct sctp_chunk * chunk,const struct sctp_association * asoc)395 sctp_vtag_verify(const struct sctp_chunk *chunk,
396 const struct sctp_association *asoc)
397 {
398 /* RFC 2960 Sec 8.5 When receiving an SCTP packet, the endpoint
399 * MUST ensure that the value in the Verification Tag field of
400 * the received SCTP packet matches its own Tag. If the received
401 * Verification Tag value does not match the receiver's own
402 * tag value, the receiver shall silently discard the packet...
403 */
404 if (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)
405 return 1;
406
407 return 0;
408 }
409
410 /* Check VTAG of the packet matches the sender's own tag and the T bit is
411 * not set, OR its peer's tag and the T bit is set in the Chunk Flags.
412 */
413 static inline int
sctp_vtag_verify_either(const struct sctp_chunk * chunk,const struct sctp_association * asoc)414 sctp_vtag_verify_either(const struct sctp_chunk *chunk,
415 const struct sctp_association *asoc)
416 {
417 /* RFC 2960 Section 8.5.1, sctpimpguide Section 2.41
418 *
419 * B) The receiver of a ABORT MUST accept the packet
420 * if the Verification Tag field of the packet matches its own tag
421 * and the T bit is not set
422 * OR
423 * it is set to its peer's tag and the T bit is set in the Chunk
424 * Flags.
425 * Otherwise, the receiver MUST silently discard the packet
426 * and take no further action.
427 *
428 * C) The receiver of a SHUTDOWN COMPLETE shall accept the packet
429 * if the Verification Tag field of the packet matches its own tag
430 * and the T bit is not set
431 * OR
432 * it is set to its peer's tag and the T bit is set in the Chunk
433 * Flags.
434 * Otherwise, the receiver MUST silently discard the packet
435 * and take no further action. An endpoint MUST ignore the
436 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
437 */
438 if ((!sctp_test_T_bit(chunk) &&
439 (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)) ||
440 (sctp_test_T_bit(chunk) && asoc->c.peer_vtag &&
441 (ntohl(chunk->sctp_hdr->vtag) == asoc->c.peer_vtag))) {
442 return 1;
443 }
444
445 return 0;
446 }
447
448 #endif /* __sctp_sm_h__ */
449