xref: /openbmc/linux/include/net/sctp/sm.h (revision 6774def6)
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, see
25  * <http://www.gnu.org/licenses/>.
26  *
27  * Please send any bug reports or fixes you make to the
28  * email addresses:
29  *    lksctp developers <linux-sctp@vger.kernel.org>
30  *
31  * Written or modified by:
32  *    La Monte H.P. Yarroll <piggy@acm.org>
33  *    Karl Knutson <karl@athena.chicago.il.us>
34  *    Xingang Guo <xingang.guo@intel.com>
35  *    Jon Grimm <jgrimm@us.ibm.com>
36  *    Dajiang Zhang <dajiang.zhang@nokia.com>
37  *    Sridhar Samudrala <sri@us.ibm.com>
38  *    Daisy Chang <daisyc@us.ibm.com>
39  *    Ardelle Fan <ardelle.fan@intel.com>
40  *    Kevin Gao <kevin.gao@intel.com>
41  */
42 
43 #include <linux/types.h>
44 #include <linux/compiler.h>
45 #include <linux/slab.h>
46 #include <linux/in.h>
47 #include <net/sctp/command.h>
48 #include <net/sctp/sctp.h>
49 
50 #ifndef __sctp_sm_h__
51 #define __sctp_sm_h__
52 
53 /*
54  * Possible values for the disposition are:
55  */
56 typedef enum {
57 	SCTP_DISPOSITION_DISCARD,	 /* No further processing.  */
58 	SCTP_DISPOSITION_CONSUME,	 /* Process return values normally.  */
59 	SCTP_DISPOSITION_NOMEM,		 /* We ran out of memory--recover.  */
60 	SCTP_DISPOSITION_DELETE_TCB,	 /* Close the association.  */
61 	SCTP_DISPOSITION_ABORT,		 /* Close the association NOW.  */
62 	SCTP_DISPOSITION_VIOLATION,	 /* The peer is misbehaving.  */
63 	SCTP_DISPOSITION_NOT_IMPL,	 /* This entry is not implemented.  */
64 	SCTP_DISPOSITION_ERROR,		 /* This is plain old user error.  */
65 	SCTP_DISPOSITION_BUG,		 /* This is a bug.  */
66 } sctp_disposition_t;
67 
68 typedef struct {
69 	int name;
70 	int action;
71 } sctp_sm_command_t;
72 
73 typedef sctp_disposition_t (sctp_state_fn_t) (struct net *,
74 					      const struct sctp_endpoint *,
75 					      const struct sctp_association *,
76 					      const sctp_subtype_t type,
77 					      void *arg,
78 					      sctp_cmd_seq_t *);
79 typedef void (sctp_timer_event_t) (unsigned long);
80 typedef struct {
81 	sctp_state_fn_t *fn;
82 	const char *name;
83 } sctp_sm_table_entry_t;
84 
85 /* A naming convention of "sctp_sf_xxx" applies to all the state functions
86  * currently in use.
87  */
88 
89 /* Prototypes for generic state functions. */
90 sctp_state_fn_t sctp_sf_not_impl;
91 sctp_state_fn_t sctp_sf_bug;
92 
93 /* Prototypes for gener timer state functions. */
94 sctp_state_fn_t sctp_sf_timer_ignore;
95 
96 /* Prototypes for chunk state functions. */
97 sctp_state_fn_t sctp_sf_do_9_1_abort;
98 sctp_state_fn_t sctp_sf_cookie_wait_abort;
99 sctp_state_fn_t sctp_sf_cookie_echoed_abort;
100 sctp_state_fn_t sctp_sf_shutdown_pending_abort;
101 sctp_state_fn_t sctp_sf_shutdown_sent_abort;
102 sctp_state_fn_t sctp_sf_shutdown_ack_sent_abort;
103 sctp_state_fn_t sctp_sf_do_5_1B_init;
104 sctp_state_fn_t sctp_sf_do_5_1C_ack;
105 sctp_state_fn_t sctp_sf_do_5_1D_ce;
106 sctp_state_fn_t sctp_sf_do_5_1E_ca;
107 sctp_state_fn_t sctp_sf_do_4_C;
108 sctp_state_fn_t sctp_sf_eat_data_6_2;
109 sctp_state_fn_t sctp_sf_eat_data_fast_4_4;
110 sctp_state_fn_t sctp_sf_eat_sack_6_2;
111 sctp_state_fn_t sctp_sf_operr_notify;
112 sctp_state_fn_t sctp_sf_t1_init_timer_expire;
113 sctp_state_fn_t sctp_sf_t1_cookie_timer_expire;
114 sctp_state_fn_t sctp_sf_t2_timer_expire;
115 sctp_state_fn_t sctp_sf_t4_timer_expire;
116 sctp_state_fn_t sctp_sf_t5_timer_expire;
117 sctp_state_fn_t sctp_sf_sendbeat_8_3;
118 sctp_state_fn_t sctp_sf_beat_8_3;
119 sctp_state_fn_t sctp_sf_backbeat_8_3;
120 sctp_state_fn_t sctp_sf_do_9_2_final;
121 sctp_state_fn_t sctp_sf_do_9_2_shutdown;
122 sctp_state_fn_t sctp_sf_do_9_2_shut_ctsn;
123 sctp_state_fn_t sctp_sf_do_ecn_cwr;
124 sctp_state_fn_t sctp_sf_do_ecne;
125 sctp_state_fn_t sctp_sf_ootb;
126 sctp_state_fn_t sctp_sf_pdiscard;
127 sctp_state_fn_t sctp_sf_violation;
128 sctp_state_fn_t sctp_sf_discard_chunk;
129 sctp_state_fn_t sctp_sf_do_5_2_1_siminit;
130 sctp_state_fn_t sctp_sf_do_5_2_2_dupinit;
131 sctp_state_fn_t sctp_sf_do_5_2_3_initack;
132 sctp_state_fn_t sctp_sf_do_5_2_4_dupcook;
133 sctp_state_fn_t sctp_sf_unk_chunk;
134 sctp_state_fn_t sctp_sf_do_8_5_1_E_sa;
135 sctp_state_fn_t sctp_sf_cookie_echoed_err;
136 sctp_state_fn_t sctp_sf_do_asconf;
137 sctp_state_fn_t sctp_sf_do_asconf_ack;
138 sctp_state_fn_t sctp_sf_do_9_2_reshutack;
139 sctp_state_fn_t sctp_sf_eat_fwd_tsn;
140 sctp_state_fn_t sctp_sf_eat_fwd_tsn_fast;
141 sctp_state_fn_t sctp_sf_eat_auth;
142 
143 /* Prototypes for primitive event state functions.  */
144 sctp_state_fn_t sctp_sf_do_prm_asoc;
145 sctp_state_fn_t sctp_sf_do_prm_send;
146 sctp_state_fn_t sctp_sf_do_9_2_prm_shutdown;
147 sctp_state_fn_t sctp_sf_cookie_wait_prm_shutdown;
148 sctp_state_fn_t sctp_sf_cookie_echoed_prm_shutdown;
149 sctp_state_fn_t sctp_sf_do_9_1_prm_abort;
150 sctp_state_fn_t sctp_sf_cookie_wait_prm_abort;
151 sctp_state_fn_t sctp_sf_cookie_echoed_prm_abort;
152 sctp_state_fn_t sctp_sf_shutdown_pending_prm_abort;
153 sctp_state_fn_t sctp_sf_shutdown_sent_prm_abort;
154 sctp_state_fn_t sctp_sf_shutdown_ack_sent_prm_abort;
155 sctp_state_fn_t sctp_sf_error_closed;
156 sctp_state_fn_t sctp_sf_error_shutdown;
157 sctp_state_fn_t sctp_sf_ignore_primitive;
158 sctp_state_fn_t sctp_sf_do_prm_requestheartbeat;
159 sctp_state_fn_t sctp_sf_do_prm_asconf;
160 
161 /* Prototypes for other event state functions.  */
162 sctp_state_fn_t sctp_sf_do_no_pending_tsn;
163 sctp_state_fn_t sctp_sf_do_9_2_start_shutdown;
164 sctp_state_fn_t sctp_sf_do_9_2_shutdown_ack;
165 sctp_state_fn_t sctp_sf_ignore_other;
166 sctp_state_fn_t sctp_sf_cookie_wait_icmp_abort;
167 
168 /* Prototypes for timeout event state functions.  */
169 sctp_state_fn_t sctp_sf_do_6_3_3_rtx;
170 sctp_state_fn_t sctp_sf_do_6_2_sack;
171 sctp_state_fn_t sctp_sf_autoclose_timer_expire;
172 
173 /* Prototypes for utility support functions.  */
174 __u8 sctp_get_chunk_type(struct sctp_chunk *chunk);
175 const sctp_sm_table_entry_t *sctp_sm_lookup_event(struct net *,
176 					    sctp_event_t,
177 					    sctp_state_t,
178 					    sctp_subtype_t);
179 int sctp_chunk_iif(const struct sctp_chunk *);
180 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *,
181 					     struct sctp_chunk *,
182 					     gfp_t gfp);
183 __u32 sctp_generate_verification_tag(void);
184 void sctp_populate_tie_tags(__u8 *cookie, __u32 curTag, __u32 hisTag);
185 
186 /* Prototypes for chunk-building functions.  */
187 struct sctp_chunk *sctp_make_init(const struct sctp_association *,
188 			     const struct sctp_bind_addr *,
189 			     gfp_t gfp, int vparam_len);
190 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *,
191 				 const struct sctp_chunk *,
192 				 const gfp_t gfp,
193 				 const int unkparam_len);
194 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *,
195 				    const struct sctp_chunk *);
196 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *,
197 				   const struct sctp_chunk *);
198 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *,
199 				 const __u32 lowest_tsn,
200 				 const struct sctp_chunk *);
201 struct sctp_chunk * sctp_make_datafrag_empty(struct sctp_association *,
202 					const struct sctp_sndrcvinfo *sinfo,
203 					int len, const __u8 flags,
204 					__u16 ssn);
205 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *,
206 				  const __u32);
207 struct sctp_chunk *sctp_make_sack(const struct sctp_association *);
208 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
209 				      const struct sctp_chunk *chunk);
210 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
211 					  const struct sctp_chunk *);
212 struct sctp_chunk *sctp_make_shutdown_complete(const struct sctp_association *,
213 					  const struct sctp_chunk *);
214 void sctp_init_cause(struct sctp_chunk *, __be16 cause, size_t);
215 struct sctp_chunk *sctp_make_abort(const struct sctp_association *,
216 			      const struct sctp_chunk *,
217 			      const size_t hint);
218 struct sctp_chunk *sctp_make_abort_no_data(const struct sctp_association *,
219 				      const struct sctp_chunk *,
220 				      __u32 tsn);
221 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *,
222 					const struct msghdr *, size_t msg_len);
223 struct sctp_chunk *sctp_make_abort_violation(const struct sctp_association *,
224 				   const struct sctp_chunk *,
225 				   const __u8 *,
226 				   const size_t );
227 struct sctp_chunk *sctp_make_violation_paramlen(const struct sctp_association *,
228 				   const struct sctp_chunk *,
229 				   struct sctp_paramhdr *);
230 struct sctp_chunk *sctp_make_violation_max_retrans(const struct sctp_association *,
231 						   const struct sctp_chunk *);
232 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *,
233 				  const struct sctp_transport *);
234 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *,
235 				      const struct sctp_chunk *,
236 				      const void *payload,
237 				      const size_t paylen);
238 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *,
239 				 const struct sctp_chunk *chunk,
240 				 __be16 cause_code,
241 				 const void *payload,
242 				 size_t paylen,
243 				 size_t reserve_tail);
244 
245 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *,
246 					      union sctp_addr *,
247 					      struct sockaddr *,
248 					      int, __be16);
249 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
250 					     union sctp_addr *addr);
251 bool sctp_verify_asconf(const struct sctp_association *asoc,
252 			struct sctp_chunk *chunk, bool addr_param_needed,
253 			struct sctp_paramhdr **errp);
254 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
255 				       struct sctp_chunk *asconf);
256 int sctp_process_asconf_ack(struct sctp_association *asoc,
257 			    struct sctp_chunk *asconf_ack);
258 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
259 				    __u32 new_cum_tsn, size_t nstreams,
260 				    struct sctp_fwdtsn_skip *skiplist);
261 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc);
262 
263 void sctp_chunk_assign_tsn(struct sctp_chunk *);
264 void sctp_chunk_assign_ssn(struct sctp_chunk *);
265 
266 /* Prototypes for statetable processing. */
267 
268 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
269 	       sctp_state_t state,
270                struct sctp_endpoint *,
271                struct sctp_association *asoc,
272                void *event_arg,
273 	       gfp_t gfp);
274 
275 /* 2nd level prototypes */
276 void sctp_generate_t3_rtx_event(unsigned long peer);
277 void sctp_generate_heartbeat_event(unsigned long peer);
278 void sctp_generate_proto_unreach_event(unsigned long peer);
279 
280 void sctp_ootb_pkt_free(struct sctp_packet *);
281 
282 struct sctp_association *sctp_unpack_cookie(const struct sctp_endpoint *,
283 				       const struct sctp_association *,
284 				       struct sctp_chunk *,
285 				       gfp_t gfp, int *err,
286 				       struct sctp_chunk **err_chk_p);
287 int sctp_addip_addr_config(struct sctp_association *, sctp_param_t,
288 			   struct sockaddr_storage*, int);
289 
290 /* 3rd level prototypes */
291 __u32 sctp_generate_tag(const struct sctp_endpoint *);
292 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
293 
294 /* Extern declarations for major data structures.  */
295 extern sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES];
296 
297 
298 /* Get the size of a DATA chunk payload. */
299 static inline __u16 sctp_data_size(struct sctp_chunk *chunk)
300 {
301 	__u16 size;
302 
303 	size = ntohs(chunk->chunk_hdr->length);
304 	size -= sizeof(sctp_data_chunk_t);
305 
306 	return size;
307 }
308 
309 /* Compare two TSNs */
310 
311 /* RFC 1982 - Serial Number Arithmetic
312  *
313  * 2. Comparison
314  *  Then, s1 is said to be equal to s2 if and only if i1 is equal to i2,
315  *  in all other cases, s1 is not equal to s2.
316  *
317  * s1 is said to be less than s2 if, and only if, s1 is not equal to s2,
318  * and
319  *
320  *      (i1 < i2 and i2 - i1 < 2^(SERIAL_BITS - 1)) or
321  *      (i1 > i2 and i1 - i2 > 2^(SERIAL_BITS - 1))
322  *
323  * s1 is said to be greater than s2 if, and only if, s1 is not equal to
324  * s2, and
325  *
326  *      (i1 < i2 and i2 - i1 > 2^(SERIAL_BITS - 1)) or
327  *      (i1 > i2 and i1 - i2 < 2^(SERIAL_BITS - 1))
328  */
329 
330 /*
331  * RFC 2960
332  *  1.6 Serial Number Arithmetic
333  *
334  * Comparisons and arithmetic on TSNs in this document SHOULD use Serial
335  * Number Arithmetic as defined in [RFC1982] where SERIAL_BITS = 32.
336  */
337 
338 enum {
339 	TSN_SIGN_BIT = (1<<31)
340 };
341 
342 static inline int TSN_lt(__u32 s, __u32 t)
343 {
344 	return ((s) - (t)) & TSN_SIGN_BIT;
345 }
346 
347 static inline int TSN_lte(__u32 s, __u32 t)
348 {
349 	return ((s) == (t)) || (((s) - (t)) & TSN_SIGN_BIT);
350 }
351 
352 /* Compare two SSNs */
353 
354 /*
355  * RFC 2960
356  *  1.6 Serial Number Arithmetic
357  *
358  * Comparisons and arithmetic on Stream Sequence Numbers in this document
359  * SHOULD use Serial Number Arithmetic as defined in [RFC1982] where
360  * SERIAL_BITS = 16.
361  */
362 enum {
363 	SSN_SIGN_BIT = (1<<15)
364 };
365 
366 static inline int SSN_lt(__u16 s, __u16 t)
367 {
368 	return ((s) - (t)) & SSN_SIGN_BIT;
369 }
370 
371 static inline int SSN_lte(__u16 s, __u16 t)
372 {
373 	return ((s) == (t)) || (((s) - (t)) & SSN_SIGN_BIT);
374 }
375 
376 /*
377  * ADDIP 3.1.1
378  * The valid range of Serial Number is from 0 to 4294967295 (2**32 - 1). Serial
379  * Numbers wrap back to 0 after reaching 4294967295.
380  */
381 enum {
382 	ADDIP_SERIAL_SIGN_BIT = (1<<31)
383 };
384 
385 static inline int ADDIP_SERIAL_gte(__u16 s, __u16 t)
386 {
387 	return ((s) == (t)) || (((t) - (s)) & ADDIP_SERIAL_SIGN_BIT);
388 }
389 
390 /* Check VTAG of the packet matches the sender's own tag. */
391 static inline int
392 sctp_vtag_verify(const struct sctp_chunk *chunk,
393 		 const struct sctp_association *asoc)
394 {
395 	/* RFC 2960 Sec 8.5 When receiving an SCTP packet, the endpoint
396 	 * MUST ensure that the value in the Verification Tag field of
397 	 * the received SCTP packet matches its own Tag. If the received
398 	 * Verification Tag value does not match the receiver's own
399 	 * tag value, the receiver shall silently discard the packet...
400 	 */
401         if (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)
402                 return 1;
403 
404 	return 0;
405 }
406 
407 /* Check VTAG of the packet matches the sender's own tag and the T bit is
408  * not set, OR its peer's tag and the T bit is set in the Chunk Flags.
409  */
410 static inline int
411 sctp_vtag_verify_either(const struct sctp_chunk *chunk,
412 			const struct sctp_association *asoc)
413 {
414         /* RFC 2960 Section 8.5.1, sctpimpguide Section 2.41
415 	 *
416 	 * B) The receiver of a ABORT MUST accept the packet
417 	 *    if the Verification Tag field of the packet matches its own tag
418 	 *    and the T bit is not set
419 	 *    OR
420 	 *    it is set to its peer's tag and the T bit is set in the Chunk
421 	 *    Flags.
422 	 *    Otherwise, the receiver MUST silently discard the packet
423 	 *    and take no further action.
424 	 *
425 	 * C) The receiver of a SHUTDOWN COMPLETE shall accept the packet
426 	 *    if the Verification Tag field of the packet matches its own tag
427 	 *    and the T bit is not set
428 	 *    OR
429 	 *    it is set to its peer's tag and the T bit is set in the Chunk
430 	 *    Flags.
431 	 *    Otherwise, the receiver MUST silently discard the packet
432 	 *    and take no further action.  An endpoint MUST ignore the
433 	 *    SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
434 	 */
435         if ((!sctp_test_T_bit(chunk) &&
436              (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)) ||
437 	    (sctp_test_T_bit(chunk) && asoc->c.peer_vtag &&
438 	     (ntohl(chunk->sctp_hdr->vtag) == asoc->c.peer_vtag))) {
439                 return 1;
440 	}
441 
442 	return 0;
443 }
444 
445 #endif /* __sctp_sm_h__ */
446