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   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 "port.h"
  42 #include "ref.h"
  43
  44 /**
  45  * struct subscriber - TIPC network topology subscriber
  46  * @port_ref: object reference to server port connecting to subscriber
  47  * @lock: pointer to spinlock controlling access to subscriber's server port
  48  * @subscriber_list: adjacent subscribers in top. server's list of subscribers
  49  * @subscription_list: list of subscription objects for this subscriber
  50  */
  51
  52 struct subscriber {
  53         u32 port_ref;
  54         spinlock_t *lock;
  55         struct list_head subscriber_list;
  56         struct list_head subscription_list;
  57 };
  58
  59 /**
  60  * struct top_srv - TIPC network topology subscription service
  61  * @user_ref: TIPC userid of subscription service
  62  * @setup_port: reference to TIPC port that handles subscription requests
  63  * @subscription_count: number of active subscriptions (not subscribers!)
  64  * @subscriber_list: list of ports subscribing to service
  65  * @lock: spinlock govering access to subscriber list
  66  */
  67
  68 struct top_srv {
  69         u32 user_ref;
  70         u32 setup_port;
  71         atomic_t subscription_count;
  72         struct list_head subscriber_list;
  73         spinlock_t lock;
  74 };
  75
  76 static struct top_srv topsrv = { 0 };
  77
  78 /**
  79  * htohl - convert value to endianness used by destination
  80  * @in: value to convert
  81  * @swap: non-zero if endianness must be reversed
  82  *
  83  * Returns converted value
  84  */
  85
  86 static u32 htohl(u32 in, int swap)
  87 {
  88         return swap ? (u32)___constant_swab32(in) : in;
  89 }
  90
  91 /**
  92  * subscr_send_event - send a message containing a tipc_event to the subscriber
  93  *
  94  * Note: Must not hold subscriber's server port lock, since tipc_send() will
  95  *       try to take the lock if the message is rejected and returned!
  96  */
  97
  98 static void subscr_send_event(struct subscription *sub,
  99                               u32 found_lower,
 100                               u32 found_upper,
 101                               u32 event,
 102                               u32 port_ref,
 103                               u32 node)
 104 {
 105         struct iovec msg_sect;
 106
 107         msg_sect.iov_base = (void *)&sub->evt;
 108         msg_sect.iov_len = sizeof(struct tipc_event);
 109
 110         sub->evt.event = htohl(event, sub->swap);
 111         sub->evt.found_lower = htohl(found_lower, sub->swap);
 112         sub->evt.found_upper = htohl(found_upper, sub->swap);
 113         sub->evt.port.ref = htohl(port_ref, sub->swap);
 114         sub->evt.port.node = htohl(node, sub->swap);
 115         tipc_send(sub->server_ref, 1, &msg_sect);
 116 }
 117
 118 /**
 119  * tipc_subscr_overlap - test for subscription overlap with the given values
 120  *
 121  * Returns 1 if there is overlap, otherwise 0.
 122  */
 123
 124 int tipc_subscr_overlap(struct subscription *sub,
 125                         u32 found_lower,
 126                         u32 found_upper)
 127
 128 {
 129         if (found_lower < sub->seq.lower)
 130                 found_lower = sub->seq.lower;
 131         if (found_upper > sub->seq.upper)
 132                 found_upper = sub->seq.upper;
 133         if (found_lower > found_upper)
 134                 return 0;
 135         return 1;
 136 }
 137
 138 /**
 139  * tipc_subscr_report_overlap - issue event if there is subscription overlap
 140  *
 141  * Protected by nameseq.lock in name_table.c
 142  */
 143
 144 void tipc_subscr_report_overlap(struct subscription *sub,
 145                                 u32 found_lower,
 146                                 u32 found_upper,
 147                                 u32 event,
 148                                 u32 port_ref,
 149                                 u32 node,
 150                                 int must)
 151 {
 152         dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
 153             sub->seq.upper, found_lower, found_upper);
 154         if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 155                 return;
 156         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 157                 return;
 158
 159         sub->event_cb(sub, found_lower, found_upper, event, port_ref, node);
 160 }
 161
 162 /**
 163  * subscr_timeout - subscription timeout has occurred
 164  */
 165
 166 static void subscr_timeout(struct subscription *sub)
 167 {
 168         struct port *server_port;
 169
 170         /* Validate server port reference (in case subscriber is terminating) */
 171
 172         server_port = tipc_port_lock(sub->server_ref);
 173         if (server_port == NULL)
 174                 return;
 175
 176         /* Validate timeout (in case subscription is being cancelled) */
 177
 178         if (sub->timeout == TIPC_WAIT_FOREVER) {
 179                 tipc_port_unlock(server_port);
 180                 return;
 181         }
 182
 183         /* Unlink subscription from name table */
 184
 185         tipc_nametbl_unsubscribe(sub);
 186
 187         /* Unlink subscription from subscriber */
 188
 189         list_del(&sub->subscription_list);
 190
 191         /* Release subscriber's server port */
 192
 193         tipc_port_unlock(server_port);
 194
 195         /* Notify subscriber of timeout */
 196
 197         subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 198                           TIPC_SUBSCR_TIMEOUT, 0, 0);
 199
 200         /* Now destroy subscription */
 201
 202         k_term_timer(&sub->timer);
 203         kfree(sub);
 204         atomic_dec(&topsrv.subscription_count);
 205 }
 206
 207 /**
 208  * subscr_del - delete a subscription within a subscription list
 209  *
 210  * Called with subscriber port locked.
 211  */
 212
 213 static void subscr_del(struct subscription *sub)
 214 {
 215         tipc_nametbl_unsubscribe(sub);
 216         list_del(&sub->subscription_list);
 217         kfree(sub);
 218         atomic_dec(&topsrv.subscription_count);
 219 }
 220
 221 /**
 222  * subscr_terminate - terminate communication with a subscriber
 223  *
 224  * Called with subscriber port locked.  Routine must temporarily release lock
 225  * to enable subscription timeout routine(s) to finish without deadlocking;
 226  * the lock is then reclaimed to allow caller to release it upon return.
 227  * (This should work even in the unlikely event some other thread creates
 228  * a new object reference in the interim that uses this lock; this routine will
 229  * simply wait for it to be released, then claim it.)
 230  */
 231
 232 static void subscr_terminate(struct subscriber *subscriber)
 233 {
 234         u32 port_ref;
 235         struct subscription *sub;
 236         struct subscription *sub_temp;
 237
 238         /* Invalidate subscriber reference */
 239
 240         port_ref = subscriber->port_ref;
 241         subscriber->port_ref = 0;
 242         spin_unlock_bh(subscriber->lock);
 243
 244         /* Sever connection to subscriber */
 245
 246         tipc_shutdown(port_ref);
 247         tipc_deleteport(port_ref);
 248
 249         /* Destroy any existing subscriptions for subscriber */
 250
 251         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 252                                  subscription_list) {
 253                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 254                         k_cancel_timer(&sub->timer);
 255                         k_term_timer(&sub->timer);
 256                 }
 257                 dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
 258                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 259                 subscr_del(sub);
 260         }
 261
 262         /* Remove subscriber from topology server's subscriber list */
 263
 264         spin_lock_bh(&topsrv.lock);
 265         list_del(&subscriber->subscriber_list);
 266         spin_unlock_bh(&topsrv.lock);
 267
 268         /* Reclaim subscriber lock */
 269
 270         spin_lock_bh(subscriber->lock);
 271
 272         /* Now destroy subscriber */
 273
 274         kfree(subscriber);
 275 }
 276
 277 /**
 278  * subscr_cancel - handle subscription cancellation request
 279  *
 280  * Called with subscriber port locked.  Routine must temporarily release lock
 281  * to enable the subscription timeout routine to finish without deadlocking;
 282  * the lock is then reclaimed to allow caller to release it upon return.
 283  *
 284  * Note that fields of 's' use subscriber's endianness!
 285  */
 286
 287 static void subscr_cancel(struct tipc_subscr *s,
 288                           struct subscriber *subscriber)
 289 {
 290         struct subscription *sub;
 291         struct subscription *sub_temp;
 292         int found = 0;
 293
 294         /* Find first matching subscription, exit if not found */
 295
 296         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 297                                  subscription_list) {
 298                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 299                         found = 1;
 300                         break;
 301                 }
 302         }
 303         if (!found)
 304                 return;
 305
 306         /* Cancel subscription timer (if used), then delete subscription */
 307
 308         if (sub->timeout != TIPC_WAIT_FOREVER) {
 309                 sub->timeout = TIPC_WAIT_FOREVER;
 310                 spin_unlock_bh(subscriber->lock);
 311                 k_cancel_timer(&sub->timer);
 312                 k_term_timer(&sub->timer);
 313                 spin_lock_bh(subscriber->lock);
 314         }
 315         dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
 316             sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 317         subscr_del(sub);
 318 }
 319
 320 /**
 321  * subscr_subscribe - create subscription for subscriber
 322  *
 323  * Called with subscriber port locked.
 324  */
 325
 326 static struct subscription *subscr_subscribe(struct tipc_subscr *s,
 327                                              struct subscriber *subscriber)
 328 {
 329         struct subscription *sub;
 330         int swap;
 331
 332         /* Determine subscriber's endianness */
 333
 334         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 335
 336         /* Detect & process a subscription cancellation request */
 337
 338         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 339                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 340                 subscr_cancel(s, subscriber);
 341                 return NULL;
 342         }
 343
 344         /* Refuse subscription if global limit exceeded */
 345
 346         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 347                 warn("Subscription rejected, subscription limit reached (%u)\n",
 348                      tipc_max_subscriptions);
 349                 subscr_terminate(subscriber);
 350                 return NULL;
 351         }
 352
 353         /* Allocate subscription object */
 354
 355         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 356         if (!sub) {
 357                 warn("Subscription rejected, no memory\n");
 358                 subscr_terminate(subscriber);
 359                 return NULL;
 360         }
 361
 362         /* Initialize subscription object */
 363
 364         sub->seq.type = htohl(s->seq.type, swap);
 365         sub->seq.lower = htohl(s->seq.lower, swap);
 366         sub->seq.upper = htohl(s->seq.upper, swap);
 367         sub->timeout = htohl(s->timeout, swap);
 368         sub->filter = htohl(s->filter, swap);
 369         if ((!(sub->filter & TIPC_SUB_PORTS)
 370              == !(sub->filter & TIPC_SUB_SERVICE))
 371             || (sub->seq.lower > sub->seq.upper)) {
 372                 warn("Subscription rejected, illegal request\n");
 373                 kfree(sub);
 374                 subscr_terminate(subscriber);
 375                 return NULL;
 376         }
 377         sub->event_cb = subscr_send_event;
 378         INIT_LIST_HEAD(&sub->nameseq_list);
 379         list_add(&sub->subscription_list, &subscriber->subscription_list);
 380         sub->server_ref = subscriber->port_ref;
 381         sub->swap = swap;
 382         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 383         atomic_inc(&topsrv.subscription_count);
 384         if (sub->timeout != TIPC_WAIT_FOREVER) {
 385                 k_init_timer(&sub->timer,
 386                              (Handler)subscr_timeout, (unsigned long)sub);
 387                 k_start_timer(&sub->timer, sub->timeout);
 388         }
 389
 390         return sub;
 391 }
 392
 393 /**
 394  * subscr_conn_shutdown_event - handle termination request from subscriber
 395  *
 396  * Called with subscriber's server port unlocked.
 397  */
 398
 399 static void subscr_conn_shutdown_event(void *usr_handle,
 400                                        u32 port_ref,
 401                                        struct sk_buff **buf,
 402                                        unsigned char const *data,
 403                                        unsigned int size,
 404                                        int reason)
 405 {
 406         struct subscriber *subscriber = usr_handle;
 407         spinlock_t *subscriber_lock;
 408
 409         if (tipc_port_lock(port_ref) == NULL)
 410                 return;
 411
 412         subscriber_lock = subscriber->lock;
 413         subscr_terminate(subscriber);
 414         spin_unlock_bh(subscriber_lock);
 415 }
 416
 417 /**
 418  * subscr_conn_msg_event - handle new subscription request from subscriber
 419  *
 420  * Called with subscriber's server port unlocked.
 421  */
 422
 423 static void subscr_conn_msg_event(void *usr_handle,
 424                                   u32 port_ref,
 425                                   struct sk_buff **buf,
 426                                   const unchar *data,
 427                                   u32 size)
 428 {
 429         struct subscriber *subscriber = usr_handle;
 430         spinlock_t *subscriber_lock;
 431         struct subscription *sub;
 432
 433         /*
 434          * Lock subscriber's server port (& make a local copy of lock pointer,
 435          * in case subscriber is deleted while processing subscription request)
 436          */
 437
 438         if (tipc_port_lock(port_ref) == NULL)
 439                 return;
 440
 441         subscriber_lock = subscriber->lock;
 442
 443         if (size != sizeof(struct tipc_subscr)) {
 444                 subscr_terminate(subscriber);
 445                 spin_unlock_bh(subscriber_lock);
 446         } else {
 447                 sub = subscr_subscribe((struct tipc_subscr *)data, subscriber);
 448                 spin_unlock_bh(subscriber_lock);
 449                 if (sub != NULL) {
 450
 451                         /*
 452                          * We must release the server port lock before adding a
 453                          * subscription to the name table since TIPC needs to be
 454                          * able to (re)acquire the port lock if an event message
 455                          * issued by the subscription process is rejected and
 456                          * returned.  The subscription cannot be deleted while
 457                          * it is being added to the name table because:
 458                          * a) the single-threading of the native API port code
 459                          *    ensures the subscription cannot be cancelled and
 460                          *    the subscriber connection cannot be broken, and
 461                          * b) the name table lock ensures the subscription
 462                          *    timeout code cannot delete the subscription,
 463                          * so the subscription object is still protected.
 464                          */
 465
 466                         tipc_nametbl_subscribe(sub);
 467                 }
 468         }
 469 }
 470
 471 /**
 472  * subscr_named_msg_event - handle request to establish a new subscriber
 473  */
 474
 475 static void subscr_named_msg_event(void *usr_handle,
 476                                    u32 port_ref,
 477                                    struct sk_buff **buf,
 478                                    const unchar *data,
 479                                    u32 size,
 480                                    u32 importance,
 481                                    struct tipc_portid const *orig,
 482                                    struct tipc_name_seq const *dest)
 483 {
 484         static struct iovec msg_sect = {NULL, 0};
 485
 486         struct subscriber *subscriber;
 487         u32 server_port_ref;
 488
 489         /* Create subscriber object */
 490
 491         subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
 492         if (subscriber == NULL) {
 493                 warn("Subscriber rejected, no memory\n");
 494                 return;
 495         }
 496         INIT_LIST_HEAD(&subscriber->subscription_list);
 497         INIT_LIST_HEAD(&subscriber->subscriber_list);
 498
 499         /* Create server port & establish connection to subscriber */
 500
 501         tipc_createport(topsrv.user_ref,
 502                         subscriber,
 503                         importance,
 504                         NULL,
 505                         NULL,
 506                         subscr_conn_shutdown_event,
 507                         NULL,
 508                         NULL,
 509                         subscr_conn_msg_event,
 510                         NULL,
 511                         &subscriber->port_ref);
 512         if (subscriber->port_ref == 0) {
 513                 warn("Subscriber rejected, unable to create port\n");
 514                 kfree(subscriber);
 515                 return;
 516         }
 517         tipc_connect2port(subscriber->port_ref, orig);
 518
 519         /* Lock server port (& save lock address for future use) */
 520
 521         subscriber->lock = tipc_port_lock(subscriber->port_ref)->publ.lock;
 522
 523         /* Add subscriber to topology server's subscriber list */
 524
 525         spin_lock_bh(&topsrv.lock);
 526         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 527         spin_unlock_bh(&topsrv.lock);
 528
 529         /* Unlock server port */
 530
 531         server_port_ref = subscriber->port_ref;
 532         spin_unlock_bh(subscriber->lock);
 533
 534         /* Send an ACK- to complete connection handshaking */
 535
 536         tipc_send(server_port_ref, 1, &msg_sect);
 537
 538         /* Handle optional subscription request */
 539
 540         if (size != 0) {
 541                 subscr_conn_msg_event(subscriber, server_port_ref,
 542                                       buf, data, size);
 543         }
 544 }
 545
 546 int tipc_subscr_start(void)
 547 {
 548         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 549         int res = -1;
 550
 551         memset(&topsrv, 0, sizeof (topsrv));
 552         spin_lock_init(&topsrv.lock);
 553         INIT_LIST_HEAD(&topsrv.subscriber_list);
 554
 555         spin_lock_bh(&topsrv.lock);
 556         res = tipc_attach(&topsrv.user_ref, NULL, NULL);
 557         if (res) {
 558                 spin_unlock_bh(&topsrv.lock);
 559                 return res;
 560         }
 561
 562         res = tipc_createport(topsrv.user_ref,
 563                               NULL,
 564                               TIPC_CRITICAL_IMPORTANCE,
 565                               NULL,
 566                               NULL,
 567                               NULL,
 568                               NULL,
 569                               subscr_named_msg_event,
 570                               NULL,
 571                               NULL,
 572                               &topsrv.setup_port);
 573         if (res)
 574                 goto failed;
 575
 576         res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 577         if (res)
 578                 goto failed;
 579
 580         spin_unlock_bh(&topsrv.lock);
 581         return 0;
 582
 583 failed:
 584         err("Failed to create subscription service\n");
 585         tipc_detach(topsrv.user_ref);
 586         topsrv.user_ref = 0;
 587         spin_unlock_bh(&topsrv.lock);
 588         return res;
 589 }
 590
 591 void tipc_subscr_stop(void)
 592 {
 593         struct subscriber *subscriber;
 594         struct subscriber *subscriber_temp;
 595         spinlock_t *subscriber_lock;
 596
 597         if (topsrv.user_ref) {
 598                 tipc_deleteport(topsrv.setup_port);
 599                 list_for_each_entry_safe(subscriber, subscriber_temp,
 600                                          &topsrv.subscriber_list,
 601                                          subscriber_list) {
 602                         subscriber_lock = subscriber->lock;
 603                         spin_lock_bh(subscriber_lock);
 604                         subscr_terminate(subscriber);
 605                         spin_unlock_bh(subscriber_lock);
 606                 }
 607                 tipc_detach(topsrv.user_ref);
 608                 topsrv.user_ref = 0;
 609         }
 610 }
 611
 612
 613 int tipc_ispublished(struct tipc_name const *name)
 614 {
 615         u32 domain = 0;
 616
 617         return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
 618 }
 619