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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 "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
 161         sub->event_cb(sub, found_lower, found_upper, event, port_ref, node);
 162 }
 163
 164 /**
 165  * subscr_timeout - subscription timeout has occurred
 166  */
 167
 168 static void subscr_timeout(struct subscription *sub)
 169 {
 170         struct subscriber *subscriber;
 171         u32 subscriber_ref;
 172
 173         /* Validate subscriber reference (in case subscriber is terminating) */
 174
 175         subscriber_ref = sub->owner->ref;
 176         subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
 177         if (subscriber == NULL)
 178                 return;
 179
 180         /* Validate timeout (in case subscription is being cancelled) */
 181
 182         if (sub->timeout == TIPC_WAIT_FOREVER) {
 183                 tipc_ref_unlock(subscriber_ref);
 184                 return;
 185         }
 186
 187         /* Unlink subscription from name table */
 188
 189         tipc_nametbl_unsubscribe(sub);
 190
 191         /* Notify subscriber of timeout, then unlink subscription */
 192
 193         subscr_send_event(sub,
 194                           sub->evt.s.seq.lower,
 195                           sub->evt.s.seq.upper,
 196                           TIPC_SUBSCR_TIMEOUT,
 197                           0,
 198                           0);
 199         list_del(&sub->subscription_list);
 200
 201         /* Now destroy subscription */
 202
 203         tipc_ref_unlock(subscriber_ref);
 204         k_term_timer(&sub->timer);
 205         kfree(sub);
 206         atomic_dec(&topsrv.subscription_count);
 207 }
 208
 209 /**
 210  * subscr_del - delete a subscription within a subscription list
 211  *
 212  * Called with subscriber locked.
 213  */
 214
 215 static void subscr_del(struct subscription *sub)
 216 {
 217         tipc_nametbl_unsubscribe(sub);
 218         list_del(&sub->subscription_list);
 219         kfree(sub);
 220         atomic_dec(&topsrv.subscription_count);
 221 }
 222
 223 /**
 224  * subscr_terminate - terminate communication with a subscriber
 225  *
 226  * Called with subscriber locked.  Routine must temporarily release this lock
 227  * to enable subscription timeout routine(s) to finish without deadlocking;
 228  * the lock is then reclaimed to allow caller to release it upon return.
 229  * (This should work even in the unlikely event some other thread creates
 230  * a new object reference in the interim that uses this lock; this routine will
 231  * simply wait for it to be released, then claim it.)
 232  */
 233
 234 static void subscr_terminate(struct subscriber *subscriber)
 235 {
 236         struct subscription *sub;
 237         struct subscription *sub_temp;
 238
 239         /* Invalidate subscriber reference */
 240
 241         tipc_ref_discard(subscriber->ref);
 242         spin_unlock_bh(subscriber->lock);
 243
 244         /* Destroy any existing subscriptions for subscriber */
 245
 246         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 247                                  subscription_list) {
 248                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 249                         k_cancel_timer(&sub->timer);
 250                         k_term_timer(&sub->timer);
 251                 }
 252                 dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
 253                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 254                 subscr_del(sub);
 255         }
 256
 257         /* Sever connection to subscriber */
 258
 259         tipc_shutdown(subscriber->port_ref);
 260         tipc_deleteport(subscriber->port_ref);
 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         /* Now destroy subscriber */
 269
 270         spin_lock_bh(subscriber->lock);
 271         kfree(subscriber);
 272 }
 273
 274 /**
 275  * subscr_cancel - handle subscription cancellation request
 276  *
 277  * Called with subscriber locked.  Routine must temporarily release this lock
 278  * to enable the subscription timeout routine to finish without deadlocking;
 279  * the lock is then reclaimed to allow caller to release it upon return.
 280  *
 281  * Note that fields of 's' use subscriber's endianness!
 282  */
 283
 284 static void subscr_cancel(struct tipc_subscr *s,
 285                           struct subscriber *subscriber)
 286 {
 287         struct subscription *sub;
 288         struct subscription *sub_temp;
 289         int found = 0;
 290
 291         /* Find first matching subscription, exit if not found */
 292
 293         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 294                                  subscription_list) {
 295                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 296                         found = 1;
 297                         break;
 298                 }
 299         }
 300         if (!found)
 301                 return;
 302
 303         /* Cancel subscription timer (if used), then delete subscription */
 304
 305         if (sub->timeout != TIPC_WAIT_FOREVER) {
 306                 sub->timeout = TIPC_WAIT_FOREVER;
 307                 spin_unlock_bh(subscriber->lock);
 308                 k_cancel_timer(&sub->timer);
 309                 k_term_timer(&sub->timer);
 310                 spin_lock_bh(subscriber->lock);
 311         }
 312         dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
 313             sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 314         subscr_del(sub);
 315 }
 316
 317 /**
 318  * subscr_subscribe - create subscription for subscriber
 319  *
 320  * Called with subscriber locked
 321  */
 322
 323 static void subscr_subscribe(struct tipc_subscr *s,
 324                              struct subscriber *subscriber)
 325 {
 326         struct subscription *sub;
 327
 328         /* Determine/update subscriber's endianness */
 329
 330         if (s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE))
 331                 subscriber->swap = 0;
 332         else
 333                 subscriber->swap = 1;
 334
 335         /* Detect & process a subscription cancellation request */
 336
 337         if (s->filter & htohl(TIPC_SUB_CANCEL, subscriber->swap)) {
 338                 s->filter &= ~htohl(TIPC_SUB_CANCEL, subscriber->swap);
 339                 subscr_cancel(s, subscriber);
 340                 return;
 341         }
 342
 343         /* Refuse subscription if global limit exceeded */
 344
 345         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 346                 warn("Subscription rejected, subscription limit reached (%u)\n",
 347                      tipc_max_subscriptions);
 348                 subscr_terminate(subscriber);
 349                 return;
 350         }
 351
 352         /* Allocate subscription object */
 353
 354         sub = kzalloc(sizeof(*sub), GFP_ATOMIC);
 355         if (!sub) {
 356                 warn("Subscription rejected, no memory\n");
 357                 subscr_terminate(subscriber);
 358                 return;
 359         }
 360
 361         /* Initialize subscription object */
 362
 363         sub->seq.type = htohl(s->seq.type, subscriber->swap);
 364         sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
 365         sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
 366         sub->timeout = htohl(s->timeout, subscriber->swap);
 367         sub->filter = htohl(s->filter, subscriber->swap);
 368         if ((!(sub->filter & TIPC_SUB_PORTS)
 369              == !(sub->filter & TIPC_SUB_SERVICE))
 370             || (sub->seq.lower > sub->seq.upper)) {
 371                 warn("Subscription rejected, illegal request\n");
 372                 kfree(sub);
 373                 subscr_terminate(subscriber);
 374                 return;
 375         }
 376         sub->event_cb = subscr_send_event;
 377         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 378         INIT_LIST_HEAD(&sub->subscription_list);
 379         INIT_LIST_HEAD(&sub->nameseq_list);
 380         list_add(&sub->subscription_list, &subscriber->subscription_list);
 381         atomic_inc(&topsrv.subscription_count);
 382         if (sub->timeout != TIPC_WAIT_FOREVER) {
 383                 k_init_timer(&sub->timer,
 384                              (Handler)subscr_timeout, (unsigned long)sub);
 385                 k_start_timer(&sub->timer, sub->timeout);
 386         }
 387         sub->owner = subscriber;
 388         tipc_nametbl_subscribe(sub);
 389 }
 390
 391 /**
 392  * subscr_conn_shutdown_event - handle termination request from subscriber
 393  */
 394
 395 static void subscr_conn_shutdown_event(void *usr_handle,
 396                                        u32 portref,
 397                                        struct sk_buff **buf,
 398                                        unsigned char const *data,
 399                                        unsigned int size,
 400                                        int reason)
 401 {
 402         struct subscriber *subscriber;
 403         spinlock_t *subscriber_lock;
 404
 405         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 406         if (subscriber == NULL)
 407                 return;
 408
 409         subscriber_lock = subscriber->lock;
 410         subscr_terminate(subscriber);
 411         spin_unlock_bh(subscriber_lock);
 412 }
 413
 414 /**
 415  * subscr_conn_msg_event - handle new subscription request from subscriber
 416  */
 417
 418 static void subscr_conn_msg_event(void *usr_handle,
 419                                   u32 port_ref,
 420                                   struct sk_buff **buf,
 421                                   const unchar *data,
 422                                   u32 size)
 423 {
 424         struct subscriber *subscriber;
 425         spinlock_t *subscriber_lock;
 426
 427         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 428         if (subscriber == NULL)
 429                 return;
 430
 431         subscriber_lock = subscriber->lock;
 432         if (size != sizeof(struct tipc_subscr))
 433                 subscr_terminate(subscriber);
 434         else
 435                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 436
 437         spin_unlock_bh(subscriber_lock);
 438 }
 439
 440 /**
 441  * subscr_named_msg_event - handle request to establish a new subscriber
 442  */
 443
 444 static void subscr_named_msg_event(void *usr_handle,
 445                                    u32 port_ref,
 446                                    struct sk_buff **buf,
 447                                    const unchar *data,
 448                                    u32 size,
 449                                    u32 importance,
 450                                    struct tipc_portid const *orig,
 451                                    struct tipc_name_seq const *dest)
 452 {
 453         struct subscriber *subscriber;
 454         struct iovec msg_sect = {NULL, 0};
 455         spinlock_t *subscriber_lock;
 456
 457         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 458             orig->node, tipc_own_addr);
 459         if (size && (size != sizeof(struct tipc_subscr))) {
 460                 warn("Subscriber rejected, invalid subscription size\n");
 461                 return;
 462         }
 463
 464         /* Create subscriber object */
 465
 466         subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
 467         if (subscriber == NULL) {
 468                 warn("Subscriber rejected, no memory\n");
 469                 return;
 470         }
 471         INIT_LIST_HEAD(&subscriber->subscription_list);
 472         INIT_LIST_HEAD(&subscriber->subscriber_list);
 473         subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
 474         if (subscriber->ref == 0) {
 475                 warn("Subscriber rejected, reference table exhausted\n");
 476                 kfree(subscriber);
 477                 return;
 478         }
 479         spin_unlock_bh(subscriber->lock);
 480
 481         /* Establish a connection to subscriber */
 482
 483         tipc_createport(topsrv.user_ref,
 484                         (void *)(unsigned long)subscriber->ref,
 485                         importance,
 486                         NULL,
 487                         NULL,
 488                         subscr_conn_shutdown_event,
 489                         NULL,
 490                         NULL,
 491                         subscr_conn_msg_event,
 492                         NULL,
 493                         &subscriber->port_ref);
 494         if (subscriber->port_ref == 0) {
 495                 warn("Subscriber rejected, unable to create port\n");
 496                 tipc_ref_discard(subscriber->ref);
 497                 kfree(subscriber);
 498                 return;
 499         }
 500         tipc_connect2port(subscriber->port_ref, orig);
 501
 502
 503         /* Add subscriber to topology server's subscriber list */
 504
 505         tipc_ref_lock(subscriber->ref);
 506         spin_lock_bh(&topsrv.lock);
 507         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 508         spin_unlock_bh(&topsrv.lock);
 509
 510         /*
 511          * Subscribe now if message contains a subscription,
 512          * otherwise send an empty response to complete connection handshaking
 513          */
 514
 515         subscriber_lock = subscriber->lock;
 516         if (size)
 517                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 518         else
 519                 tipc_send(subscriber->port_ref, 1, &msg_sect);
 520
 521         spin_unlock_bh(subscriber_lock);
 522 }
 523
 524 int tipc_subscr_start(void)
 525 {
 526         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 527         int res = -1;
 528
 529         memset(&topsrv, 0, sizeof (topsrv));
 530         spin_lock_init(&topsrv.lock);
 531         INIT_LIST_HEAD(&topsrv.subscriber_list);
 532
 533         spin_lock_bh(&topsrv.lock);
 534         res = tipc_attach(&topsrv.user_ref, NULL, NULL);
 535         if (res) {
 536                 spin_unlock_bh(&topsrv.lock);
 537                 return res;
 538         }
 539
 540         res = tipc_createport(topsrv.user_ref,
 541                               NULL,
 542                               TIPC_CRITICAL_IMPORTANCE,
 543                               NULL,
 544                               NULL,
 545                               NULL,
 546                               NULL,
 547                               subscr_named_msg_event,
 548                               NULL,
 549                               NULL,
 550                               &topsrv.setup_port);
 551         if (res)
 552                 goto failed;
 553
 554         res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 555         if (res)
 556                 goto failed;
 557
 558         spin_unlock_bh(&topsrv.lock);
 559         return 0;
 560
 561 failed:
 562         err("Failed to create subscription service\n");
 563         tipc_detach(topsrv.user_ref);
 564         topsrv.user_ref = 0;
 565         spin_unlock_bh(&topsrv.lock);
 566         return res;
 567 }
 568
 569 void tipc_subscr_stop(void)
 570 {
 571         struct subscriber *subscriber;
 572         struct subscriber *subscriber_temp;
 573         spinlock_t *subscriber_lock;
 574
 575         if (topsrv.user_ref) {
 576                 tipc_deleteport(topsrv.setup_port);
 577                 list_for_each_entry_safe(subscriber, subscriber_temp,
 578                                          &topsrv.subscriber_list,
 579                                          subscriber_list) {
 580                         tipc_ref_lock(subscriber->ref);
 581                         subscriber_lock = subscriber->lock;
 582                         subscr_terminate(subscriber);
 583                         spin_unlock_bh(subscriber_lock);
 584                 }
 585                 tipc_detach(topsrv.user_ref);
 586                 topsrv.user_ref = 0;
 587         }
 588 }
 589
 590
 591 int tipc_ispublished(struct tipc_name const *name)
 592 {
 593         u32 domain = 0;
 594
 595         return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
 596 }
 597