net/tipc/subscr.c

   1 /*
   2  * net/tipc/subscr.c: TIPC subscription service
   3  *
   4  * Copyright (c) 2000-2006, Ericsson AB
   5  * Copyright (c) 2005, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "dbg.h"
  39 #include "subscr.h"
  40 #include "name_table.h"
  41 #include "ref.h"
  42
  43 /**
  44  * struct subscriber - TIPC network topology subscriber
  45  * @ref: object reference to subscriber object itself
  46  * @lock: pointer to spinlock controlling access to subscriber object
  47  * @subscriber_list: adjacent subscribers in top. server's list of subscribers
  48  * @subscription_list: list of subscription objects for this subscriber
  49  * @port_ref: object reference to port used to communicate with subscriber
  50  * @swap: indicates if subscriber uses opposite endianness in its messages
  51  */
  52
  53 struct subscriber {
  54         u32 ref;
  55         spinlock_t *lock;
  56         struct list_head subscriber_list;
  57         struct list_head subscription_list;
  58         u32 port_ref;
  59         int swap;
  60 };
  61
  62 /**
  63  * struct top_srv - TIPC network topology subscription service
  64  * @user_ref: TIPC userid of subscription service
  65  * @setup_port: reference to TIPC port that handles subscription requests
  66  * @subscription_count: number of active subscriptions (not subscribers!)
  67  * @subscriber_list: list of ports subscribing to service
  68  * @lock: spinlock govering access to subscriber list
  69  */
  70
  71 struct top_srv {
  72         u32 user_ref;
  73         u32 setup_port;
  74         atomic_t subscription_count;
  75         struct list_head subscriber_list;
  76         spinlock_t lock;
  77 };
  78
  79 static struct top_srv topsrv = { 0 };
  80
  81 /**
  82  * htohl - convert value to endianness used by destination
  83  * @in: value to convert
  84  * @swap: non-zero if endianness must be reversed
  85  *
  86  * Returns converted value
  87  */
  88
  89 static u32 htohl(u32 in, int swap)
  90 {
  91         char *c = (char *)&in;
  92
  93         return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
  94 }
  95
  96 /**
  97  * subscr_send_event - send a message containing a tipc_event to the subscriber
  98  */
  99
 100 static void subscr_send_event(struct subscription *sub,
 101                               u32 found_lower,
 102                               u32 found_upper,
 103                               u32 event,
 104                               u32 port_ref,
 105                               u32 node)
 106 {
 107         struct iovec msg_sect;
 108
 109         msg_sect.iov_base = (void *)&sub->evt;
 110         msg_sect.iov_len = sizeof(struct tipc_event);
 111
 112         sub->evt.event = htohl(event, sub->owner->swap);
 113         sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
 114         sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
 115         sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
 116         sub->evt.port.node = htohl(node, sub->owner->swap);
 117         tipc_send(sub->owner->port_ref, 1, &msg_sect);
 118 }
 119
 120 /**
 121  * tipc_subscr_overlap - test for subscription overlap with the given values
 122  *
 123  * Returns 1 if there is overlap, otherwise 0.
 124  */
 125
 126 int tipc_subscr_overlap(struct subscription *sub,
 127                         u32 found_lower,
 128                         u32 found_upper)
 129
 130 {
 131         if (found_lower < sub->seq.lower)
 132                 found_lower = sub->seq.lower;
 133         if (found_upper > sub->seq.upper)
 134                 found_upper = sub->seq.upper;
 135         if (found_lower > found_upper)
 136                 return 0;
 137         return 1;
 138 }
 139
 140 /**
 141  * tipc_subscr_report_overlap - issue event if there is subscription overlap
 142  *
 143  * Protected by nameseq.lock in name_table.c
 144  */
 145
 146 void tipc_subscr_report_overlap(struct subscription *sub,
 147                                 u32 found_lower,
 148                                 u32 found_upper,
 149                                 u32 event,
 150                                 u32 port_ref,
 151                                 u32 node,
 152                                 int must)
 153 {
 154         dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
 155             sub->seq.upper, found_lower, found_upper);
 156         if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 157                 return;
 158         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 159                 return;
 160         subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
 161 }
 162
 163 /**
 164  * subscr_timeout - subscription timeout has occurred
 165  */
 166
 167 static void subscr_timeout(struct subscription *sub)
 168 {
 169         struct subscriber *subscriber;
 170         u32 subscriber_ref;
 171
 172         /* Validate subscriber reference (in case subscriber is terminating) */
 173
 174         subscriber_ref = sub->owner->ref;
 175         subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
 176         if (subscriber == NULL)
 177                 return;
 178
 179         /* Validate timeout (in case subscription is being cancelled) */
 180
 181         if (sub->timeout == TIPC_WAIT_FOREVER) {
 182                 tipc_ref_unlock(subscriber_ref);
 183                 return;
 184         }
 185
 186         /* Unlink subscription from name table */
 187
 188         tipc_nametbl_unsubscribe(sub);
 189
 190         /* Notify subscriber of timeout, then unlink subscription */
 191
 192         subscr_send_event(sub,
 193                           sub->evt.s.seq.lower,
 194                           sub->evt.s.seq.upper,
 195                           TIPC_SUBSCR_TIMEOUT,
 196                           0,
 197                           0);
 198         list_del(&sub->subscription_list);
 199
 200         /* Now destroy subscription */
 201
 202         tipc_ref_unlock(subscriber_ref);
 203         k_term_timer(&sub->timer);
 204         kfree(sub);
 205         atomic_dec(&topsrv.subscription_count);
 206 }
 207
 208 /**
 209  * subscr_del - delete a subscription within a subscription list
 210  *
 211  * Called with subscriber locked.
 212  */
 213
 214 static void subscr_del(struct subscription *sub)
 215 {
 216         tipc_nametbl_unsubscribe(sub);
 217         list_del(&sub->subscription_list);
 218         kfree(sub);
 219         atomic_dec(&topsrv.subscription_count);
 220 }
 221
 222 /**
 223  * subscr_terminate - terminate communication with a subscriber
 224  *
 225  * Called with subscriber locked.  Routine must temporarily release this lock
 226  * to enable subscription timeout routine(s) to finish without deadlocking;
 227  * the lock is then reclaimed to allow caller to release it upon return.
 228  * (This should work even in the unlikely event some other thread creates
 229  * a new object reference in the interim that uses this lock; this routine will
 230  * simply wait for it to be released, then claim it.)
 231  */
 232
 233 static void subscr_terminate(struct subscriber *subscriber)
 234 {
 235         struct subscription *sub;
 236         struct subscription *sub_temp;
 237
 238         /* Invalidate subscriber reference */
 239
 240         tipc_ref_discard(subscriber->ref);
 241         spin_unlock_bh(subscriber->lock);
 242
 243         /* Destroy any existing subscriptions for subscriber */
 244
 245         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 246                                  subscription_list) {
 247                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 248                         k_cancel_timer(&sub->timer);
 249                         k_term_timer(&sub->timer);
 250                 }
 251                 dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
 252                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 253                 subscr_del(sub);
 254         }
 255
 256         /* Sever connection to subscriber */
 257
 258         tipc_shutdown(subscriber->port_ref);
 259         tipc_deleteport(subscriber->port_ref);
 260
 261         /* Remove subscriber from topology server's subscriber list */
 262
 263         spin_lock_bh(&topsrv.lock);
 264         list_del(&subscriber->subscriber_list);
 265         spin_unlock_bh(&topsrv.lock);
 266
 267         /* Now destroy subscriber */
 268
 269         spin_lock_bh(subscriber->lock);
 270         kfree(subscriber);
 271 }
 272
 273 /**
 274  * subscr_cancel - handle subscription cancellation request
 275  *
 276  * Called with subscriber locked.  Routine must temporarily release this lock
 277  * to enable the subscription timeout routine to finish without deadlocking;
 278  * the lock is then reclaimed to allow caller to release it upon return.
 279  *
 280  * Note that fields of 's' use subscriber's endianness!
 281  */
 282
 283 static void subscr_cancel(struct tipc_subscr *s,
 284                           struct subscriber *subscriber)
 285 {
 286         struct subscription *sub;
 287         struct subscription *sub_temp;
 288         int found = 0;
 289
 290         /* Find first matching subscription, exit if not found */
 291
 292         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 293                                  subscription_list) {
 294                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 295                         found = 1;
 296                         break;
 297                 }
 298         }
 299         if (!found)
 300                 return;
 301
 302         /* Cancel subscription timer (if used), then delete subscription */
 303
 304         if (sub->timeout != TIPC_WAIT_FOREVER) {
 305                 sub->timeout = TIPC_WAIT_FOREVER;
 306                 spin_unlock_bh(subscriber->lock);
 307                 k_cancel_timer(&sub->timer);
 308                 k_term_timer(&sub->timer);
 309                 spin_lock_bh(subscriber->lock);
 310         }
 311         dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
 312             sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 313         subscr_del(sub);
 314 }
 315
 316 /**
 317  * subscr_subscribe - create subscription for subscriber
 318  *
 319  * Called with subscriber locked
 320  */
 321
 322 static void subscr_subscribe(struct tipc_subscr *s,
 323                              struct subscriber *subscriber)
 324 {
 325         struct subscription *sub;
 326
 327         /* Determine/update subscriber's endianness */
 328
 329         if (s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE))
 330                 subscriber->swap = 0;
 331         else
 332                 subscriber->swap = 1;
 333
 334         /* Detect & process a subscription cancellation request */
 335
 336         if (s->filter & htohl(TIPC_SUB_CANCEL, subscriber->swap)) {
 337                 s->filter &= ~htohl(TIPC_SUB_CANCEL, subscriber->swap);
 338                 subscr_cancel(s, subscriber);
 339                 return;
 340         }
 341
 342         /* Refuse subscription if global limit exceeded */
 343
 344         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 345                 warn("Subscription rejected, subscription limit reached (%u)\n",
 346                      tipc_max_subscriptions);
 347                 subscr_terminate(subscriber);
 348                 return;
 349         }
 350
 351         /* Allocate subscription object */
 352
 353         sub = kzalloc(sizeof(*sub), GFP_ATOMIC);
 354         if (!sub) {
 355                 warn("Subscription rejected, no memory\n");
 356                 subscr_terminate(subscriber);
 357                 return;
 358         }
 359
 360         /* Initialize subscription object */
 361
 362         sub->seq.type = htohl(s->seq.type, subscriber->swap);
 363         sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
 364         sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
 365         sub->timeout = htohl(s->timeout, subscriber->swap);
 366         sub->filter = htohl(s->filter, subscriber->swap);
 367         if ((!(sub->filter & TIPC_SUB_PORTS)
 368              == !(sub->filter & TIPC_SUB_SERVICE))
 369             || (sub->seq.lower > sub->seq.upper)) {
 370                 warn("Subscription rejected, illegal request\n");
 371                 kfree(sub);
 372                 subscr_terminate(subscriber);
 373                 return;
 374         }
 375         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 376         INIT_LIST_HEAD(&sub->subscription_list);
 377         INIT_LIST_HEAD(&sub->nameseq_list);
 378         list_add(&sub->subscription_list, &subscriber->subscription_list);
 379         atomic_inc(&topsrv.subscription_count);
 380         if (sub->timeout != TIPC_WAIT_FOREVER) {
 381                 k_init_timer(&sub->timer,
 382                              (Handler)subscr_timeout, (unsigned long)sub);
 383                 k_start_timer(&sub->timer, sub->timeout);
 384         }
 385         sub->owner = subscriber;
 386         tipc_nametbl_subscribe(sub);
 387 }
 388
 389 /**
 390  * subscr_conn_shutdown_event - handle termination request from subscriber
 391  */
 392
 393 static void subscr_conn_shutdown_event(void *usr_handle,
 394                                        u32 portref,
 395                                        struct sk_buff **buf,
 396                                        unsigned char const *data,
 397                                        unsigned int size,
 398                                        int reason)
 399 {
 400         struct subscriber *subscriber;
 401         spinlock_t *subscriber_lock;
 402
 403         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 404         if (subscriber == NULL)
 405                 return;
 406
 407         subscriber_lock = subscriber->lock;
 408         subscr_terminate(subscriber);
 409         spin_unlock_bh(subscriber_lock);
 410 }
 411
 412 /**
 413  * subscr_conn_msg_event - handle new subscription request from subscriber
 414  */
 415
 416 static void subscr_conn_msg_event(void *usr_handle,
 417                                   u32 port_ref,
 418                                   struct sk_buff **buf,
 419                                   const unchar *data,
 420                                   u32 size)
 421 {
 422         struct subscriber *subscriber;
 423         spinlock_t *subscriber_lock;
 424
 425         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 426         if (subscriber == NULL)
 427                 return;
 428
 429         subscriber_lock = subscriber->lock;
 430         if (size != sizeof(struct tipc_subscr))
 431                 subscr_terminate(subscriber);
 432         else
 433                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 434
 435         spin_unlock_bh(subscriber_lock);
 436 }
 437
 438 /**
 439  * subscr_named_msg_event - handle request to establish a new subscriber
 440  */
 441
 442 static void subscr_named_msg_event(void *usr_handle,
 443                                    u32 port_ref,
 444                                    struct sk_buff **buf,
 445                                    const unchar *data,
 446                                    u32 size,
 447                                    u32 importance,
 448                                    struct tipc_portid const *orig,
 449                                    struct tipc_name_seq const *dest)
 450 {
 451         struct subscriber *subscriber;
 452         struct iovec msg_sect = {NULL, 0};
 453         spinlock_t *subscriber_lock;
 454
 455         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 456             orig->node, tipc_own_addr);
 457         if (size && (size != sizeof(struct tipc_subscr))) {
 458                 warn("Subscriber rejected, invalid subscription size\n");
 459                 return;
 460         }
 461
 462         /* Create subscriber object */
 463
 464         subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
 465         if (subscriber == NULL) {
 466                 warn("Subscriber rejected, no memory\n");
 467                 return;
 468         }
 469         INIT_LIST_HEAD(&subscriber->subscription_list);
 470         INIT_LIST_HEAD(&subscriber->subscriber_list);
 471         subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
 472         if (subscriber->ref == 0) {
 473                 warn("Subscriber rejected, reference table exhausted\n");
 474                 kfree(subscriber);
 475                 return;
 476         }
 477
 478         /* Establish a connection to subscriber */
 479
 480         tipc_createport(topsrv.user_ref,
 481                         (void *)(unsigned long)subscriber->ref,
 482                         importance,
 483                         NULL,
 484                         NULL,
 485                         subscr_conn_shutdown_event,
 486                         NULL,
 487                         NULL,
 488                         subscr_conn_msg_event,
 489                         NULL,
 490                         &subscriber->port_ref);
 491         if (subscriber->port_ref == 0) {
 492                 warn("Subscriber rejected, unable to create port\n");
 493                 tipc_ref_discard(subscriber->ref);
 494                 kfree(subscriber);
 495                 return;
 496         }
 497         tipc_connect2port(subscriber->port_ref, orig);
 498
 499
 500         /* Add subscriber to topology server's subscriber list */
 501
 502         tipc_ref_lock(subscriber->ref);
 503         spin_lock_bh(&topsrv.lock);
 504         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 505         spin_unlock_bh(&topsrv.lock);
 506
 507         /*
 508          * Subscribe now if message contains a subscription,
 509          * otherwise send an empty response to complete connection handshaking
 510          */
 511
 512         subscriber_lock = subscriber->lock;
 513         if (size)
 514                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 515         else
 516                 tipc_send(subscriber->port_ref, 1, &msg_sect);
 517
 518         spin_unlock_bh(subscriber_lock);
 519 }
 520
 521 int tipc_subscr_start(void)
 522 {
 523         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 524         int res = -1;
 525
 526         memset(&topsrv, 0, sizeof (topsrv));
 527         spin_lock_init(&topsrv.lock);
 528         INIT_LIST_HEAD(&topsrv.subscriber_list);
 529
 530         spin_lock_bh(&topsrv.lock);
 531         res = tipc_attach(&topsrv.user_ref, NULL, NULL);
 532         if (res) {
 533                 spin_unlock_bh(&topsrv.lock);
 534                 return res;
 535         }
 536
 537         res = tipc_createport(topsrv.user_ref,
 538                               NULL,
 539                               TIPC_CRITICAL_IMPORTANCE,
 540                               NULL,
 541                               NULL,
 542                               NULL,
 543                               NULL,
 544                               subscr_named_msg_event,
 545                               NULL,
 546                               NULL,
 547                               &topsrv.setup_port);
 548         if (res)
 549                 goto failed;
 550
 551         res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 552         if (res)
 553                 goto failed;
 554
 555         spin_unlock_bh(&topsrv.lock);
 556         return 0;
 557
 558 failed:
 559         err("Failed to create subscription service\n");
 560         tipc_detach(topsrv.user_ref);
 561         topsrv.user_ref = 0;
 562         spin_unlock_bh(&topsrv.lock);
 563         return res;
 564 }
 565
 566 void tipc_subscr_stop(void)
 567 {
 568         struct subscriber *subscriber;
 569         struct subscriber *subscriber_temp;
 570         spinlock_t *subscriber_lock;
 571
 572         if (topsrv.user_ref) {
 573                 tipc_deleteport(topsrv.setup_port);
 574                 list_for_each_entry_safe(subscriber, subscriber_temp,
 575                                          &topsrv.subscriber_list,
 576                                          subscriber_list) {
 577                         tipc_ref_lock(subscriber->ref);
 578                         subscriber_lock = subscriber->lock;
 579                         subscr_terminate(subscriber);
 580                         spin_unlock_bh(subscriber_lock);
 581                 }
 582                 tipc_detach(topsrv.user_ref);
 583                 topsrv.user_ref = 0;
 584         }
 585 }
 586
 587
 588 int tipc_ispublished(struct tipc_name const *name)
 589 {
 590         u32 domain = 0;
 591
 592         return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
 593 }
 594