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  */
  51
  52 struct subscriber {
  53         u32 ref;
  54         spinlock_t *lock;
  55         struct list_head subscriber_list;
  56         struct list_head subscription_list;
  57         u32 port_ref;
  58 };
  59
  60 /**
  61  * struct top_srv - TIPC network topology subscription service
  62  * @user_ref: TIPC userid of subscription service
  63  * @setup_port: reference to TIPC port that handles subscription requests
  64  * @subscription_count: number of active subscriptions (not subscribers!)
  65  * @subscriber_list: list of ports subscribing to service
  66  * @lock: spinlock govering access to subscriber list
  67  */
  68
  69 struct top_srv {
  70         u32 user_ref;
  71         u32 setup_port;
  72         atomic_t subscription_count;
  73         struct list_head subscriber_list;
  74         spinlock_t lock;
  75 };
  76
  77 static struct top_srv topsrv = { 0 };
  78
  79 /**
  80  * htohl - convert value to endianness used by destination
  81  * @in: value to convert
  82  * @swap: non-zero if endianness must be reversed
  83  *
  84  * Returns converted value
  85  */
  86
  87 static u32 htohl(u32 in, int swap)
  88 {
  89         return swap ? (u32)___constant_swab32(in) : in;
  90 }
  91
  92 /**
  93  * subscr_send_event - send a message containing a tipc_event to the subscriber
  94  */
  95
  96 static void subscr_send_event(struct subscription *sub,
  97                               u32 found_lower,
  98                               u32 found_upper,
  99                               u32 event,
 100                               u32 port_ref,
 101                               u32 node)
 102 {
 103         struct iovec msg_sect;
 104
 105         msg_sect.iov_base = (void *)&sub->evt;
 106         msg_sect.iov_len = sizeof(struct tipc_event);
 107
 108         sub->evt.event = htohl(event, sub->swap);
 109         sub->evt.found_lower = htohl(found_lower, sub->swap);
 110         sub->evt.found_upper = htohl(found_upper, sub->swap);
 111         sub->evt.port.ref = htohl(port_ref, sub->swap);
 112         sub->evt.port.node = htohl(node, sub->swap);
 113         tipc_send(sub->owner->port_ref, 1, &msg_sect);
 114 }
 115
 116 /**
 117  * tipc_subscr_overlap - test for subscription overlap with the given values
 118  *
 119  * Returns 1 if there is overlap, otherwise 0.
 120  */
 121
 122 int tipc_subscr_overlap(struct subscription *sub,
 123                         u32 found_lower,
 124                         u32 found_upper)
 125
 126 {
 127         if (found_lower < sub->seq.lower)
 128                 found_lower = sub->seq.lower;
 129         if (found_upper > sub->seq.upper)
 130                 found_upper = sub->seq.upper;
 131         if (found_lower > found_upper)
 132                 return 0;
 133         return 1;
 134 }
 135
 136 /**
 137  * tipc_subscr_report_overlap - issue event if there is subscription overlap
 138  *
 139  * Protected by nameseq.lock in name_table.c
 140  */
 141
 142 void tipc_subscr_report_overlap(struct subscription *sub,
 143                                 u32 found_lower,
 144                                 u32 found_upper,
 145                                 u32 event,
 146                                 u32 port_ref,
 147                                 u32 node,
 148                                 int must)
 149 {
 150         dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
 151             sub->seq.upper, found_lower, found_upper);
 152         if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 153                 return;
 154         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 155                 return;
 156
 157         sub->event_cb(sub, found_lower, found_upper, event, port_ref, node);
 158 }
 159
 160 /**
 161  * subscr_timeout - subscription timeout has occurred
 162  */
 163
 164 static void subscr_timeout(struct subscription *sub)
 165 {
 166         struct subscriber *subscriber;
 167         u32 subscriber_ref;
 168
 169         /* Validate subscriber reference (in case subscriber is terminating) */
 170
 171         subscriber_ref = sub->owner->ref;
 172         subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
 173         if (subscriber == NULL)
 174                 return;
 175
 176         /* Validate timeout (in case subscription is being cancelled) */
 177
 178         if (sub->timeout == TIPC_WAIT_FOREVER) {
 179                 tipc_ref_unlock(subscriber_ref);
 180                 return;
 181         }
 182
 183         /* Unlink subscription from name table */
 184
 185         tipc_nametbl_unsubscribe(sub);
 186
 187         /* Notify subscriber of timeout, then unlink subscription */
 188
 189         subscr_send_event(sub,
 190                           sub->evt.s.seq.lower,
 191                           sub->evt.s.seq.upper,
 192                           TIPC_SUBSCR_TIMEOUT,
 193                           0,
 194                           0);
 195         list_del(&sub->subscription_list);
 196
 197         /* Now destroy subscription */
 198
 199         tipc_ref_unlock(subscriber_ref);
 200         k_term_timer(&sub->timer);
 201         kfree(sub);
 202         atomic_dec(&topsrv.subscription_count);
 203 }
 204
 205 /**
 206  * subscr_del - delete a subscription within a subscription list
 207  *
 208  * Called with subscriber locked.
 209  */
 210
 211 static void subscr_del(struct subscription *sub)
 212 {
 213         tipc_nametbl_unsubscribe(sub);
 214         list_del(&sub->subscription_list);
 215         kfree(sub);
 216         atomic_dec(&topsrv.subscription_count);
 217 }
 218
 219 /**
 220  * subscr_terminate - terminate communication with a subscriber
 221  *
 222  * Called with subscriber locked.  Routine must temporarily release this lock
 223  * to enable subscription timeout routine(s) to finish without deadlocking;
 224  * the lock is then reclaimed to allow caller to release it upon return.
 225  * (This should work even in the unlikely event some other thread creates
 226  * a new object reference in the interim that uses this lock; this routine will
 227  * simply wait for it to be released, then claim it.)
 228  */
 229
 230 static void subscr_terminate(struct subscriber *subscriber)
 231 {
 232         struct subscription *sub;
 233         struct subscription *sub_temp;
 234
 235         /* Invalidate subscriber reference */
 236
 237         tipc_ref_discard(subscriber->ref);
 238         spin_unlock_bh(subscriber->lock);
 239
 240         /* Destroy any existing subscriptions for subscriber */
 241
 242         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 243                                  subscription_list) {
 244                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 245                         k_cancel_timer(&sub->timer);
 246                         k_term_timer(&sub->timer);
 247                 }
 248                 dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
 249                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 250                 subscr_del(sub);
 251         }
 252
 253         /* Sever connection to subscriber */
 254
 255         tipc_shutdown(subscriber->port_ref);
 256         tipc_deleteport(subscriber->port_ref);
 257
 258         /* Remove subscriber from topology server's subscriber list */
 259
 260         spin_lock_bh(&topsrv.lock);
 261         list_del(&subscriber->subscriber_list);
 262         spin_unlock_bh(&topsrv.lock);
 263
 264         /* Now destroy subscriber */
 265
 266         spin_lock_bh(subscriber->lock);
 267         kfree(subscriber);
 268 }
 269
 270 /**
 271  * subscr_cancel - handle subscription cancellation request
 272  *
 273  * Called with subscriber locked.  Routine must temporarily release this lock
 274  * to enable the subscription timeout routine to finish without deadlocking;
 275  * the lock is then reclaimed to allow caller to release it upon return.
 276  *
 277  * Note that fields of 's' use subscriber's endianness!
 278  */
 279
 280 static void subscr_cancel(struct tipc_subscr *s,
 281                           struct subscriber *subscriber)
 282 {
 283         struct subscription *sub;
 284         struct subscription *sub_temp;
 285         int found = 0;
 286
 287         /* Find first matching subscription, exit if not found */
 288
 289         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 290                                  subscription_list) {
 291                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 292                         found = 1;
 293                         break;
 294                 }
 295         }
 296         if (!found)
 297                 return;
 298
 299         /* Cancel subscription timer (if used), then delete subscription */
 300
 301         if (sub->timeout != TIPC_WAIT_FOREVER) {
 302                 sub->timeout = TIPC_WAIT_FOREVER;
 303                 spin_unlock_bh(subscriber->lock);
 304                 k_cancel_timer(&sub->timer);
 305                 k_term_timer(&sub->timer);
 306                 spin_lock_bh(subscriber->lock);
 307         }
 308         dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
 309             sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 310         subscr_del(sub);
 311 }
 312
 313 /**
 314  * subscr_subscribe - create subscription for subscriber
 315  *
 316  * Called with subscriber locked
 317  */
 318
 319 static void subscr_subscribe(struct tipc_subscr *s,
 320                              struct subscriber *subscriber)
 321 {
 322         struct subscription *sub;
 323         int swap;
 324
 325         /* Determine subscriber's endianness */
 326
 327         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 328
 329         /* Detect & process a subscription cancellation request */
 330
 331         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 332                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 333                 subscr_cancel(s, subscriber);
 334                 return;
 335         }
 336
 337         /* Refuse subscription if global limit exceeded */
 338
 339         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 340                 warn("Subscription rejected, subscription limit reached (%u)\n",
 341                      tipc_max_subscriptions);
 342                 subscr_terminate(subscriber);
 343                 return;
 344         }
 345
 346         /* Allocate subscription object */
 347
 348         sub = kzalloc(sizeof(*sub), GFP_ATOMIC);
 349         if (!sub) {
 350                 warn("Subscription rejected, no memory\n");
 351                 subscr_terminate(subscriber);
 352                 return;
 353         }
 354
 355         /* Initialize subscription object */
 356
 357         sub->seq.type = htohl(s->seq.type, swap);
 358         sub->seq.lower = htohl(s->seq.lower, swap);
 359         sub->seq.upper = htohl(s->seq.upper, swap);
 360         sub->timeout = htohl(s->timeout, swap);
 361         sub->filter = htohl(s->filter, swap);
 362         if ((!(sub->filter & TIPC_SUB_PORTS)
 363              == !(sub->filter & TIPC_SUB_SERVICE))
 364             || (sub->seq.lower > sub->seq.upper)) {
 365                 warn("Subscription rejected, illegal request\n");
 366                 kfree(sub);
 367                 subscr_terminate(subscriber);
 368                 return;
 369         }
 370         sub->event_cb = subscr_send_event;
 371         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 372         INIT_LIST_HEAD(&sub->subscription_list);
 373         INIT_LIST_HEAD(&sub->nameseq_list);
 374         list_add(&sub->subscription_list, &subscriber->subscription_list);
 375         sub->swap = swap;
 376         atomic_inc(&topsrv.subscription_count);
 377         if (sub->timeout != TIPC_WAIT_FOREVER) {
 378                 k_init_timer(&sub->timer,
 379                              (Handler)subscr_timeout, (unsigned long)sub);
 380                 k_start_timer(&sub->timer, sub->timeout);
 381         }
 382         sub->owner = subscriber;
 383         tipc_nametbl_subscribe(sub);
 384 }
 385
 386 /**
 387  * subscr_conn_shutdown_event - handle termination request from subscriber
 388  */
 389
 390 static void subscr_conn_shutdown_event(void *usr_handle,
 391                                        u32 portref,
 392                                        struct sk_buff **buf,
 393                                        unsigned char const *data,
 394                                        unsigned int size,
 395                                        int reason)
 396 {
 397         struct subscriber *subscriber;
 398         spinlock_t *subscriber_lock;
 399
 400         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 401         if (subscriber == NULL)
 402                 return;
 403
 404         subscriber_lock = subscriber->lock;
 405         subscr_terminate(subscriber);
 406         spin_unlock_bh(subscriber_lock);
 407 }
 408
 409 /**
 410  * subscr_conn_msg_event - handle new subscription request from subscriber
 411  */
 412
 413 static void subscr_conn_msg_event(void *usr_handle,
 414                                   u32 port_ref,
 415                                   struct sk_buff **buf,
 416                                   const unchar *data,
 417                                   u32 size)
 418 {
 419         struct subscriber *subscriber;
 420         spinlock_t *subscriber_lock;
 421
 422         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 423         if (subscriber == NULL)
 424                 return;
 425
 426         subscriber_lock = subscriber->lock;
 427         if (size != sizeof(struct tipc_subscr))
 428                 subscr_terminate(subscriber);
 429         else
 430                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 431
 432         spin_unlock_bh(subscriber_lock);
 433 }
 434
 435 /**
 436  * subscr_named_msg_event - handle request to establish a new subscriber
 437  */
 438
 439 static void subscr_named_msg_event(void *usr_handle,
 440                                    u32 port_ref,
 441                                    struct sk_buff **buf,
 442                                    const unchar *data,
 443                                    u32 size,
 444                                    u32 importance,
 445                                    struct tipc_portid const *orig,
 446                                    struct tipc_name_seq const *dest)
 447 {
 448         struct subscriber *subscriber;
 449         struct iovec msg_sect = {NULL, 0};
 450         spinlock_t *subscriber_lock;
 451
 452         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 453             orig->node, tipc_own_addr);
 454         if (size && (size != sizeof(struct tipc_subscr))) {
 455                 warn("Subscriber rejected, invalid subscription size\n");
 456                 return;
 457         }
 458
 459         /* Create subscriber object */
 460
 461         subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
 462         if (subscriber == NULL) {
 463                 warn("Subscriber rejected, no memory\n");
 464                 return;
 465         }
 466         INIT_LIST_HEAD(&subscriber->subscription_list);
 467         INIT_LIST_HEAD(&subscriber->subscriber_list);
 468         subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
 469         if (subscriber->ref == 0) {
 470                 warn("Subscriber rejected, reference table exhausted\n");
 471                 kfree(subscriber);
 472                 return;
 473         }
 474         spin_unlock_bh(subscriber->lock);
 475
 476         /* Establish a connection to subscriber */
 477
 478         tipc_createport(topsrv.user_ref,
 479                         (void *)(unsigned long)subscriber->ref,
 480                         importance,
 481                         NULL,
 482                         NULL,
 483                         subscr_conn_shutdown_event,
 484                         NULL,
 485                         NULL,
 486                         subscr_conn_msg_event,
 487                         NULL,
 488                         &subscriber->port_ref);
 489         if (subscriber->port_ref == 0) {
 490                 warn("Subscriber rejected, unable to create port\n");
 491                 tipc_ref_discard(subscriber->ref);
 492                 kfree(subscriber);
 493                 return;
 494         }
 495         tipc_connect2port(subscriber->port_ref, orig);
 496
 497
 498         /* Add subscriber to topology server's subscriber list */
 499
 500         tipc_ref_lock(subscriber->ref);
 501         spin_lock_bh(&topsrv.lock);
 502         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 503         spin_unlock_bh(&topsrv.lock);
 504
 505         /*
 506          * Subscribe now if message contains a subscription,
 507          * otherwise send an empty response to complete connection handshaking
 508          */
 509
 510         subscriber_lock = subscriber->lock;
 511         if (size)
 512                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 513         else
 514                 tipc_send(subscriber->port_ref, 1, &msg_sect);
 515
 516         spin_unlock_bh(subscriber_lock);
 517 }
 518
 519 int tipc_subscr_start(void)
 520 {
 521         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 522         int res = -1;
 523
 524         memset(&topsrv, 0, sizeof (topsrv));
 525         spin_lock_init(&topsrv.lock);
 526         INIT_LIST_HEAD(&topsrv.subscriber_list);
 527
 528         spin_lock_bh(&topsrv.lock);
 529         res = tipc_attach(&topsrv.user_ref, NULL, NULL);
 530         if (res) {
 531                 spin_unlock_bh(&topsrv.lock);
 532                 return res;
 533         }
 534
 535         res = tipc_createport(topsrv.user_ref,
 536                               NULL,
 537                               TIPC_CRITICAL_IMPORTANCE,
 538                               NULL,
 539                               NULL,
 540                               NULL,
 541                               NULL,
 542                               subscr_named_msg_event,
 543                               NULL,
 544                               NULL,
 545                               &topsrv.setup_port);
 546         if (res)
 547                 goto failed;
 548
 549         res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 550         if (res)
 551                 goto failed;
 552
 553         spin_unlock_bh(&topsrv.lock);
 554         return 0;
 555
 556 failed:
 557         err("Failed to create subscription service\n");
 558         tipc_detach(topsrv.user_ref);
 559         topsrv.user_ref = 0;
 560         spin_unlock_bh(&topsrv.lock);
 561         return res;
 562 }
 563
 564 void tipc_subscr_stop(void)
 565 {
 566         struct subscriber *subscriber;
 567         struct subscriber *subscriber_temp;
 568         spinlock_t *subscriber_lock;
 569
 570         if (topsrv.user_ref) {
 571                 tipc_deleteport(topsrv.setup_port);
 572                 list_for_each_entry_safe(subscriber, subscriber_temp,
 573                                          &topsrv.subscriber_list,
 574                                          subscriber_list) {
 575                         tipc_ref_lock(subscriber->ref);
 576                         subscriber_lock = subscriber->lock;
 577                         subscr_terminate(subscriber);
 578                         spin_unlock_bh(subscriber_lock);
 579                 }
 580                 tipc_detach(topsrv.user_ref);
 581                 topsrv.user_ref = 0;
 582         }
 583 }
 584
 585
 586 int tipc_ispublished(struct tipc_name const *name)
 587 {
 588         u32 domain = 0;
 589
 590         return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
 591 }
 592