usr.sbin/atm/scspd/scsp_hfsm.c

   1 /*
   2  *
   3  * ===================================
   4  * HARP  |  Host ATM Research Platform
   5  * ===================================
   6  *
   7  *
   8  * This Host ATM Research Platform ("HARP") file (the "Software") is
   9  * made available by Network Computing Services, Inc. ("NetworkCS")
  10  * "AS IS".  NetworkCS does not provide maintenance, improvements or
  11  * support of any kind.
  12  *
  13  * NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED,
  14  * INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY
  15  * AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE
  16  * SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE.
  17  * In no event shall NetworkCS be responsible for any damages, including
  18  * but not limited to consequential damages, arising from or relating to
  19  * any use of the Software or related support.
  20  *
  21  * Copyright 1994-1998 Network Computing Services, Inc.
  22  *
  23  * Copies of this Software may be made, however, the above copyright
  24  * notice must be reproduced on all copies.
  25  *
  26  *      @(#) $FreeBSD: src/usr.sbin/atm/scspd/scsp_hfsm.c,v 1.3 1999/08/28 01:15:33 peter Exp $
  27  *      @(#) $DragonFly: src/usr.sbin/atm/scspd/scsp_hfsm.c,v 1.4 2003/11/15 20:33:43 eirikn Exp $
  28  */
  29
  30
  31 /*
  32  * Server Cache Synchronization Protocol (SCSP) Support
  33  * ----------------------------------------------------
  34  *
  35  * HELLO finite state machine
  36  *
  37  */
  38
  39 #include <sys/types.h>
  40 #include <sys/param.h>
  41 #include <sys/socket.h>
  42 #include <net/if.h>
  43 #include <netinet/in.h>
  44 #include <netatm/queue.h>
  45 #include <netatm/atm.h>
  46 #include <netatm/atm_if.h>
  47 #include <netatm/atm_sap.h>
  48 #include <netatm/atm_sys.h>
  49 #include <netatm/atm_ioctl.h>
  50
  51 #include <errno.h>
  52 #include <libatm.h>
  53 #include <stdio.h>
  54 #include <syslog.h>
  55
  56 #include "scsp_msg.h"
  57 #include "scsp_if.h"
  58 #include "scsp_var.h"
  59
  60 /*
  61  * HELLO FSM actions
  62  */
  63 #define HELLO_ACTION_CNT        7
  64 int     scsp_hello_act_00(Scsp_dcs *, Scsp_msg *);
  65 int     scsp_hello_act_01(Scsp_dcs *, Scsp_msg *);
  66 int     scsp_hello_act_02(Scsp_dcs *, Scsp_msg *);
  67 int     scsp_hello_act_03(Scsp_dcs *, Scsp_msg *);
  68 int     scsp_hello_act_04(Scsp_dcs *, Scsp_msg *);
  69 int     scsp_hello_act_05(Scsp_dcs *, Scsp_msg *);
  70 int     scsp_hello_act_06(Scsp_dcs *, Scsp_msg *);
  71
  72 static int (*scsp_action_vector[HELLO_ACTION_CNT])() = {
  73         scsp_hello_act_00,
  74         scsp_hello_act_01,
  75         scsp_hello_act_02,
  76         scsp_hello_act_03,
  77         scsp_hello_act_04,
  78         scsp_hello_act_05,
  79         scsp_hello_act_06
  80 };
  81
  82 /*
  83  * HELLO FSM state table
  84  */
  85 static int hello_state_table[SCSP_HFSM_EVENT_CNT][SCSP_HFSM_STATE_CNT] = {
  86         /* 0  1  2  3                */
  87         {  1, 1, 1, 1 },        /* 0 */
  88         {  0, 2, 2, 2 },        /* 1 */
  89         {  0, 3, 3, 3 },        /* 2 */
  90         {  0, 0, 4, 4 },        /* 3 */
  91         {  0, 5, 5, 6 },        /* 4 */
  92 };
  93
  94 /*
  95  * HELLO finite state machine
  96  *
  97  * Arguments:
  98  *      dcsp    pointer to a DCS control block for the neighbor
  99  *      event   the event which has occurred
 100  *      msg     pointer to received message, if there is one
 101  *
 102  * Returns:
 103  *      0       success
 104  *      errno   error encountered
 105  *
 106  */
 107 int
 108 scsp_hfsm(Scsp_dcs *dcsp, int event, Scsp_msg *msg)
 109 {
 110         int     action, rc, state;
 111
 112         /*
 113          * Select an action from the state table
 114          */
 115         state = dcsp->sd_hello_state;
 116         action = hello_state_table[event][state];
 117         if (scsp_trace_mode & SCSP_TRACE_HFSM) {
 118                 scsp_trace("HFSM: state=%d, event=%d, action=%d\n",
 119                                 state, event, action);
 120         }
 121         if (action >= HELLO_ACTION_CNT || action <= 0) {
 122                 scsp_log(LOG_ERR, "Hello FSM--invalid action %d; state=%d, event=%d",
 123                                 action, dcsp->sd_hello_state, event);
 124                 abort();
 125         }
 126
 127         /*
 128          * Perform the selected action
 129          */
 130         rc = scsp_action_vector[action](dcsp, msg);
 131
 132         return(rc);
 133 }
 134
 135
 136 /*
 137  * HELLO finite state machine action 0
 138  * Unexpected action -- log an error message
 139  *
 140  * Arguments:
 141  *      dcsp    pointer to DCS control block
 142  *      msg     pointer to received message (ignored)
 143  *
 144  * Returns:
 145  *      EOPNOTSUPP      always returns EOPNOTSUPP
 146  *
 147  */
 148 int
 149 scsp_hello_act_00(Scsp_dcs *dcsp, Scsp_msg *msg)
 150 {
 151         scsp_log(LOG_ERR, "Hello FSM error--unexpected action, state=%d",
 152                         dcsp->sd_hello_state);
 153         return(EOPNOTSUPP);
 154 }
 155
 156
 157 /*
 158  * HELLO finite state machine action 1
 159  * VCC open -- send HELLO message, start hello timer, go to Waiting
 160  * state
 161  *
 162  * Arguments:
 163  *      dcsp    pointer to DCS control block
 164  *      msg     pointer to received message (ignored)
 165  *
 166  * Returns:
 167  *      0       success
 168  *      errno   error encountered
 169  *
 170  */
 171 int
 172 scsp_hello_act_01(Scsp_dcs *dcsp, Scsp_msg *msg)
 173 {
 174         int             rc;
 175
 176         /*
 177          * Cancel the VCC open timer if it's running
 178          */
 179         HARP_CANCEL(&dcsp->sd_open_t);
 180
 181         /*
 182          * Go to Waiting state
 183          */
 184         dcsp->sd_hello_state = SCSP_HFSM_WAITING;
 185
 186         /*
 187          * Send a Hello message
 188          */
 189         rc = scsp_send_hello(dcsp);
 190         if (rc == 0) {
 191                 /*
 192                  * Success--start the Hello timer
 193                  */
 194                 HARP_TIMER(&dcsp->sd_hello_h_t, SCSP_HELLO_Interval,
 195                                 scsp_hello_timeout);
 196         }
 197
 198         return(rc);
 199 }
 200
 201
 202 /*
 203  * HELLO finite state machine action 2
 204  * VCC closed -- notify CA FSM, go to Down state, try to re-open VCC
 205  *
 206  * Arguments:
 207  *      dcsp    pointer to DCS control block
 208  *      msg     pointer to received message (ignored)
 209  *
 210  * Returns:
 211  *      0       success
 212  *      errno   error encountered
 213  *
 214  */
 215 int
 216 scsp_hello_act_02(Scsp_dcs *dcsp, Scsp_msg *msg)
 217 {
 218         int             rc;
 219
 220         /*
 221          * Cancel any current timers
 222          */
 223         HARP_CANCEL(&dcsp->sd_hello_h_t);
 224         HARP_CANCEL(&dcsp->sd_hello_rcv_t);
 225
 226         /*
 227          * Log the loss of the VCC
 228          */
 229         if (dcsp->sd_hello_state > SCSP_HFSM_WAITING) {
 230                 scsp_log(LOG_ERR, "VC to %s closed",
 231                                 format_atm_addr(&dcsp->sd_addr));
 232         }
 233
 234         /*
 235          * Tell the CA FSM that the conection to the DCS is lost
 236          */
 237         rc = scsp_cafsm(dcsp, SCSP_CAFSM_HELLO_DOWN, (void *)0);
 238
 239         /*
 240          * Go to Down state
 241          */
 242         dcsp->sd_hello_state = SCSP_HFSM_DOWN;
 243
 244         /*
 245          * If our ID is lower than the DCS's, wait a second before
 246          * trying to connect.  This should keep both of us from
 247          * trying to connect at the same time, resulting in two
 248          * VCCs being open.
 249          */
 250         if (scsp_cmp_id(&dcsp->sd_server->ss_lsid,
 251                         &dcsp->sd_dcsid) < 0) {
 252                 /*
 253                  * Our ID is lower--start the VCC open timer for one
 254                  * second so we'll try to open the VCC if the DCS
 255                  * doesn't do it by then
 256                  */
 257                 HARP_TIMER(&dcsp->sd_open_t, 1, scsp_open_timeout);
 258         } else {
 259                 /*
 260                  * Our ID is higher--try to reopen the VCC immediately
 261                  */
 262                 if (scsp_dcs_connect(dcsp)) {
 263                         /*
 264                          * Conncect failed -- set a timer and try
 265                          * again later
 266                          */
 267                         HARP_TIMER(&dcsp->sd_open_t, SCSP_Open_Interval,
 268                                         scsp_open_timeout);
 269                 }
 270         }
 271
 272         return(0);
 273 }
 274
 275
 276 /*
 277  * HELLO finite state machine action 3
 278  * Hello timer expired -- send HELLO message, restart hello timer
 279  *
 280  * Arguments:
 281  *      dcsp    pointer to DCS control block
 282  *      msg     pointer to received message (ignored)
 283  *
 284  * Returns:
 285  *      0       success
 286  *      errno   error encountered
 287  *
 288  */
 289 int
 290 scsp_hello_act_03(Scsp_dcs *dcsp, Scsp_msg *msg)
 291 {
 292         int             rc;
 293
 294         /*
 295          * Send a Hello message
 296          */
 297         rc = scsp_send_hello(dcsp);
 298         if (rc == 0) {
 299                 /*
 300                  * Success--restart the Hello timer
 301                  */
 302                 HARP_TIMER(&dcsp->sd_hello_h_t, SCSP_HELLO_Interval,
 303                                 scsp_hello_timeout);
 304         }
 305
 306         return(rc);
 307 }
 308
 309
 310 /*
 311  * HELLO finite state machine action 4
 312  * Receive timer expired -- if we haven't received any Hellos, notify
 313  * CA FSM and go to Waiting state;  if we've received Hellos, but we
 314  * weren't in the receiver ID list, go to Unidirectional state
 315  *
 316  * Arguments:
 317  *      dcsp    pointer to DCS control block
 318  *      msg     pointer to received message (ignored)
 319  *
 320  * Returns:
 321  *      0       success
 322  *      errno   error encountered
 323  *
 324  */
 325 int
 326 scsp_hello_act_04(Scsp_dcs *dcsp, Scsp_msg *msg)
 327 {
 328         int     rc = 0;
 329
 330         /*
 331          * Check whether we'ver received any Hellos lately
 332          */
 333         if (dcsp->sd_hello_rcvd) {
 334                 /*
 335                  * We've had Hellos since the receive timer was
 336                  * started--go to Unidirectional state
 337                  */
 338                 dcsp->sd_hello_rcvd = 0;
 339                 dcsp->sd_hello_state = SCSP_HFSM_UNI_DIR;
 340         } else {
 341                 /*
 342                  * We haven't seen any Hellos at all from the DCS in
 343                  * hello_interval * dead_factor seconds--go to Waiting
 344                  * state
 345                  */
 346                 dcsp->sd_hello_state = SCSP_HFSM_WAITING;
 347         }
 348
 349         /*
 350          * Notify the CA FSM
 351          */
 352         rc = scsp_cafsm(dcsp, SCSP_CAFSM_HELLO_DOWN, (void *)0);
 353
 354         return(rc);
 355 }
 356
 357
 358 /*
 359  * HELLO finite state machine action 5
 360  * Message received -- Ignore all but HELLO messages;  if local server
 361  * is in receiver list, notify CA FSM and go to Bidirectional state;
 362  * otherwise, go to Unidirectional state
 363  *
 364  * Arguments:
 365  *      dcsp    pointer to DCS control block
 366  *      msg     pointer to received message
 367  *
 368  * Returns:
 369  *      0       success
 370  *      errno   error encountered
 371  *
 372  */
 373 int
 374 scsp_hello_act_05(Scsp_dcs *dcsp, Scsp_msg *msg)
 375 {
 376         int     rc;
 377         Scsp_id *ridp;
 378
 379         /*
 380          * Null message pointer means message decode failed, so
 381          * message must have been invalid.  Go to Waiting state.
 382          */
 383         if (msg == (Scsp_msg *)0) {
 384                 dcsp->sd_hello_state = SCSP_HFSM_WAITING;
 385                 HARP_CANCEL(&dcsp->sd_hello_rcv_t);
 386                 return(0);
 387         }
 388
 389         /*
 390          * Ignore the message if it isn't a Hello
 391          */
 392         if (msg->sc_msg_type != SCSP_HELLO_MSG) {
 393                 return(0);
 394         }
 395
 396         /*
 397          * Save relevant information about DCS, but don't let him give
 398          * us zero for timeout values
 399          */
 400         if (msg->sc_hello->hello_int) {
 401                 dcsp->sd_hello_int = msg->sc_hello->hello_int;
 402         } else {
 403                 dcsp->sd_hello_int = 1;
 404         }
 405         if (msg->sc_hello->dead_factor) {
 406                 dcsp->sd_hello_df = msg->sc_hello->dead_factor;
 407         } else {
 408                 dcsp->sd_hello_df = 1;
 409         }
 410         dcsp->sd_dcsid = msg->sc_hello->hello_mcp.sid;
 411
 412         /*
 413          * Check the message for the local server's ID
 414          */
 415         for (ridp = &msg->sc_hello->hello_mcp.rid;
 416                         ridp;
 417                         ridp = ridp->next) {
 418                 if (scsp_cmp_id(&dcsp->sd_server->ss_lsid, ridp) == 0) {
 419                         /*
 420                          * Cancel and restart the receive timer
 421                          */
 422                         HARP_CANCEL(&dcsp->sd_hello_rcv_t);
 423                         HARP_TIMER(&dcsp->sd_hello_rcv_t,
 424                                         dcsp->sd_hello_int * dcsp->sd_hello_df,
 425                                         scsp_hello_rcv_timeout);
 426
 427                         /*
 428                          * Go to Bidirectional state and notify the
 429                          * CA FSM that the connection is up
 430                          */
 431                         dcsp->sd_hello_state = SCSP_HFSM_BI_DIR;
 432                         rc = scsp_cafsm(dcsp,
 433                                         SCSP_CAFSM_HELLO_UP,
 434                                         (void *)0);
 435                         return(rc);
 436                 }
 437         }
 438
 439         /*
 440          * We weren't in the receiver ID list, so go to
 441          * Unidirectional state
 442          */
 443         dcsp->sd_hello_state = SCSP_HFSM_UNI_DIR;
 444
 445         return(0);
 446 }
 447
 448
 449 /*
 450  * HELLO finite state machine action 6
 451  * Message received -- if message is not a HELLO, pass it to the CA
 452  * FSM;  otherwise, if local server is not in receiver list, notify
 453  * CA FSM and go to Unidirectional state
 454  *
 455  * Arguments:
 456  *      dcsp    pointer to DCS control block
 457  *      msg     pointer to received message
 458  *
 459  * Returns:
 460  *      0       success
 461  *      errno   error encountered
 462  *
 463  */
 464 int
 465 scsp_hello_act_06(Scsp_dcs *dcsp, Scsp_msg *msg)
 466 {
 467         int     rc = 0, rcv_found;
 468         Scsp_id *ridp;
 469
 470         /*
 471          * Null message pointer means message decode failed, so
 472          * message must have been invalid.  Go to Waiting state.
 473          */
 474         if (msg == (Scsp_msg *)0) {
 475                 HARP_CANCEL(&dcsp->sd_hello_rcv_t);
 476                 dcsp->sd_hello_state = SCSP_HFSM_WAITING;
 477                 rc = scsp_cafsm(dcsp, SCSP_CAFSM_HELLO_DOWN, (void *)0);
 478                 return(rc);
 479         }
 480
 481         /*
 482          * Process the message depending on its type
 483          */
 484         switch(msg->sc_msg_type) {
 485         case SCSP_CA_MSG:
 486                 rc = scsp_cafsm(dcsp, SCSP_CAFSM_CA_MSG, (void *)msg);
 487                 break;
 488         case SCSP_CSU_REQ_MSG:
 489                 rc = scsp_cafsm(dcsp, SCSP_CAFSM_CSU_REQ, (void *)msg);
 490                 break;
 491         case SCSP_CSU_REPLY_MSG:
 492                 rc = scsp_cafsm(dcsp, SCSP_CAFSM_CSU_REPLY,
 493                                 (void *)msg);
 494                 break;
 495         case SCSP_CSUS_MSG:
 496                 rc = scsp_cafsm(dcsp, SCSP_CAFSM_CSUS_MSG, (void *)msg);
 497                 break;
 498         case SCSP_HELLO_MSG:
 499                 /*
 500                  * Make sure DCS info is consistent.  The sender ID,
 501                  * family ID, protocol ID, and server group ID are
 502                  * checked.
 503                  */
 504                 if (scsp_cmp_id(&msg->sc_hello->hello_mcp.sid,
 505                                         &dcsp->sd_dcsid) ||
 506                                 (msg->sc_hello->family_id !=
 507                                         dcsp->sd_server->ss_fid) ||
 508                                 (msg->sc_hello->hello_mcp.pid !=
 509                                         dcsp->sd_server->ss_pid) ||
 510                                 (msg->sc_hello->hello_mcp.sgid !=
 511                                         dcsp->sd_server->ss_sgid)) {
 512                         /*
 513                          * Bad info--revert to waiting state
 514                          */
 515                         HARP_CANCEL(&dcsp->sd_hello_rcv_t);
 516                         dcsp->sd_hello_state = SCSP_HFSM_WAITING;
 517                         rc = scsp_cafsm(dcsp,
 518                                         SCSP_CAFSM_HELLO_DOWN,
 519                                         (void *)0);
 520                         return(rc);
 521                 }
 522
 523                 /*
 524                  * Mark the arrival of the Hello message
 525                  */
 526                 dcsp->sd_hello_rcvd = 1;
 527
 528                 /*
 529                  * Check the message for the local server's ID
 530                  */
 531                 for (ridp = &msg->sc_hello->hello_mcp.rid,
 532                                         rcv_found = 0;
 533                                 ridp;
 534                                 ridp = ridp->next) {
 535                         rcv_found = (scsp_cmp_id(ridp,
 536                                 &dcsp->sd_server->ss_lsid) == 0);
 537                 }
 538
 539                 if (rcv_found) {
 540                         /*
 541                          * The LS ID was in the list of receiver IDs--
 542                          * Reset the Hello receive timer
 543                          */
 544                         dcsp->sd_hello_rcvd = 0;
 545                         HARP_CANCEL(&dcsp->sd_hello_rcv_t);
 546                         HARP_TIMER(&dcsp->sd_hello_rcv_t,
 547                                         dcsp->sd_hello_int *
 548                                                 dcsp->sd_hello_df,
 549                                         scsp_hello_rcv_timeout);
 550                 }
 551                 break;
 552         }
 553
 554         return(rc);
 555 }