include/net/sctp/sm.h

   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                                         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__ */