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         /* Unlink subscription from name table */
 180
 181         tipc_nametbl_unsubscribe(sub);
 182
 183         /* Notify subscriber of timeout, then unlink subscription */
 184
 185         subscr_send_event(sub,
 186                           sub->evt.s.seq.lower,
 187                           sub->evt.s.seq.upper,
 188                           TIPC_SUBSCR_TIMEOUT,
 189                           0,
 190                           0);
 191         list_del(&sub->subscription_list);
 192
 193         /* Now destroy subscription */
 194
 195         tipc_ref_unlock(subscriber_ref);
 196         k_term_timer(&sub->timer);
 197         kfree(sub);
 198         atomic_dec(&topsrv.subscription_count);
 199 }
 200
 201 /**
 202  * subscr_terminate - terminate communication with a subscriber
 203  *
 204  * Called with subscriber locked.  Routine must temporarily release this lock
 205  * to enable subscription timeout routine(s) to finish without deadlocking;
 206  * the lock is then reclaimed to allow caller to release it upon return.
 207  * (This should work even in the unlikely event some other thread creates
 208  * a new object reference in the interim that uses this lock; this routine will
 209  * simply wait for it to be released, then claim it.)
 210  */
 211
 212 static void subscr_terminate(struct subscriber *subscriber)
 213 {
 214         struct subscription *sub;
 215         struct subscription *sub_temp;
 216
 217         /* Invalidate subscriber reference */
 218
 219         tipc_ref_discard(subscriber->ref);
 220         spin_unlock_bh(subscriber->lock);
 221
 222         /* Destroy any existing subscriptions for subscriber */
 223
 224         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 225                                  subscription_list) {
 226                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 227                         k_cancel_timer(&sub->timer);
 228                         k_term_timer(&sub->timer);
 229                 }
 230                 tipc_nametbl_unsubscribe(sub);
 231                 list_del(&sub->subscription_list);
 232                 dbg("Term: Removed sub %u,%u,%u from subscriber %x list\n",
 233                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 234                 kfree(sub);
 235                 atomic_dec(&topsrv.subscription_count);
 236         }
 237
 238         /* Sever connection to subscriber */
 239
 240         tipc_shutdown(subscriber->port_ref);
 241         tipc_deleteport(subscriber->port_ref);
 242
 243         /* Remove subscriber from topology server's subscriber list */
 244
 245         spin_lock_bh(&topsrv.lock);
 246         list_del(&subscriber->subscriber_list);
 247         spin_unlock_bh(&topsrv.lock);
 248
 249         /* Now destroy subscriber */
 250
 251         spin_lock_bh(subscriber->lock);
 252         kfree(subscriber);
 253 }
 254
 255 /**
 256  * subscr_subscribe - create subscription for subscriber
 257  *
 258  * Called with subscriber locked
 259  */
 260
 261 static void subscr_subscribe(struct tipc_subscr *s,
 262                              struct subscriber *subscriber)
 263 {
 264         struct subscription *sub;
 265
 266         /* Refuse subscription if global limit exceeded */
 267
 268         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 269                 warn("Subscription rejected, subscription limit reached (%u)\n",
 270                      tipc_max_subscriptions);
 271                 subscr_terminate(subscriber);
 272                 return;
 273         }
 274
 275         /* Allocate subscription object */
 276
 277         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 278         if (!sub) {
 279                 warn("Subscription rejected, no memory\n");
 280                 subscr_terminate(subscriber);
 281                 return;
 282         }
 283
 284         /* Determine/update subscriber's endianness */
 285
 286         if ((s->filter == TIPC_SUB_PORTS) || (s->filter == TIPC_SUB_SERVICE))
 287                 subscriber->swap = 0;
 288         else
 289                 subscriber->swap = 1;
 290
 291         /* Initialize subscription object */
 292
 293         memset(sub, 0, sizeof(*sub));
 294         sub->seq.type = htohl(s->seq.type, subscriber->swap);
 295         sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
 296         sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
 297         sub->timeout = htohl(s->timeout, subscriber->swap);
 298         sub->filter = htohl(s->filter, subscriber->swap);
 299         if ((((sub->filter != TIPC_SUB_PORTS)
 300               && (sub->filter != TIPC_SUB_SERVICE)))
 301             || (sub->seq.lower > sub->seq.upper)) {
 302                 warn("Subscription rejected, illegal request\n");
 303                 kfree(sub);
 304                 subscr_terminate(subscriber);
 305                 return;
 306         }
 307         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 308         INIT_LIST_HEAD(&sub->subscription_list);
 309         INIT_LIST_HEAD(&sub->nameseq_list);
 310         list_add(&sub->subscription_list, &subscriber->subscription_list);
 311         atomic_inc(&topsrv.subscription_count);
 312         if (sub->timeout != TIPC_WAIT_FOREVER) {
 313                 k_init_timer(&sub->timer,
 314                              (Handler)subscr_timeout, (unsigned long)sub);
 315                 k_start_timer(&sub->timer, sub->timeout);
 316         }
 317         sub->owner = subscriber;
 318         tipc_nametbl_subscribe(sub);
 319 }
 320
 321 /**
 322  * subscr_conn_shutdown_event - handle termination request from subscriber
 323  */
 324
 325 static void subscr_conn_shutdown_event(void *usr_handle,
 326                                        u32 portref,
 327                                        struct sk_buff **buf,
 328                                        unsigned char const *data,
 329                                        unsigned int size,
 330                                        int reason)
 331 {
 332         struct subscriber *subscriber;
 333         spinlock_t *subscriber_lock;
 334
 335         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 336         if (subscriber == NULL)
 337                 return;
 338
 339         subscriber_lock = subscriber->lock;
 340         subscr_terminate(subscriber);
 341         spin_unlock_bh(subscriber_lock);
 342 }
 343
 344 /**
 345  * subscr_conn_msg_event - handle new subscription request from subscriber
 346  */
 347
 348 static void subscr_conn_msg_event(void *usr_handle,
 349                                   u32 port_ref,
 350                                   struct sk_buff **buf,
 351                                   const unchar *data,
 352                                   u32 size)
 353 {
 354         struct subscriber *subscriber;
 355         spinlock_t *subscriber_lock;
 356
 357         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 358         if (subscriber == NULL)
 359                 return;
 360
 361         subscriber_lock = subscriber->lock;
 362         if (size != sizeof(struct tipc_subscr))
 363                 subscr_terminate(subscriber);
 364         else
 365                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 366
 367         spin_unlock_bh(subscriber_lock);
 368 }
 369
 370 /**
 371  * subscr_named_msg_event - handle request to establish a new subscriber
 372  */
 373
 374 static void subscr_named_msg_event(void *usr_handle,
 375                                    u32 port_ref,
 376                                    struct sk_buff **buf,
 377                                    const unchar *data,
 378                                    u32 size,
 379                                    u32 importance,
 380                                    struct tipc_portid const *orig,
 381                                    struct tipc_name_seq const *dest)
 382 {
 383         struct subscriber *subscriber;
 384         struct iovec msg_sect = {NULL, 0};
 385         spinlock_t *subscriber_lock;
 386
 387         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 388             orig->node, tipc_own_addr);
 389         if (size && (size != sizeof(struct tipc_subscr))) {
 390                 warn("Subscriber rejected, invalid subscription size\n");
 391                 return;
 392         }
 393
 394         /* Create subscriber object */
 395
 396         subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
 397         if (subscriber == NULL) {
 398                 warn("Subscriber rejected, no memory\n");
 399                 return;
 400         }
 401         INIT_LIST_HEAD(&subscriber->subscription_list);
 402         INIT_LIST_HEAD(&subscriber->subscriber_list);
 403         subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
 404         if (subscriber->ref == 0) {
 405                 warn("Subscriber rejected, reference table exhausted\n");
 406                 kfree(subscriber);
 407                 return;
 408         }
 409
 410         /* Establish a connection to subscriber */
 411
 412         tipc_createport(topsrv.user_ref,
 413                         (void *)(unsigned long)subscriber->ref,
 414                         importance,
 415                         NULL,
 416                         NULL,
 417                         subscr_conn_shutdown_event,
 418                         NULL,
 419                         NULL,
 420                         subscr_conn_msg_event,
 421                         NULL,
 422                         &subscriber->port_ref);
 423         if (subscriber->port_ref == 0) {
 424                 warn("Subscriber rejected, unable to create port\n");
 425                 tipc_ref_discard(subscriber->ref);
 426                 kfree(subscriber);
 427                 return;
 428         }
 429         tipc_connect2port(subscriber->port_ref, orig);
 430
 431
 432         /* Add subscriber to topology server's subscriber list */
 433
 434         tipc_ref_lock(subscriber->ref);
 435         spin_lock_bh(&topsrv.lock);
 436         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 437         spin_unlock_bh(&topsrv.lock);
 438
 439         /*
 440          * Subscribe now if message contains a subscription,
 441          * otherwise send an empty response to complete connection handshaking
 442          */
 443
 444         subscriber_lock = subscriber->lock;
 445         if (size)
 446                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 447         else
 448                 tipc_send(subscriber->port_ref, 1, &msg_sect);
 449
 450         spin_unlock_bh(subscriber_lock);
 451 }
 452
 453 int tipc_subscr_start(void)
 454 {
 455         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 456         int res = -1;
 457
 458         memset(&topsrv, 0, sizeof (topsrv));
 459         spin_lock_init(&topsrv.lock);
 460         INIT_LIST_HEAD(&topsrv.subscriber_list);
 461
 462         spin_lock_bh(&topsrv.lock);
 463         res = tipc_attach(&topsrv.user_ref, NULL, NULL);
 464         if (res) {
 465                 spin_unlock_bh(&topsrv.lock);
 466                 return res;
 467         }
 468
 469         res = tipc_createport(topsrv.user_ref,
 470                               NULL,
 471                               TIPC_CRITICAL_IMPORTANCE,
 472                               NULL,
 473                               NULL,
 474                               NULL,
 475                               NULL,
 476                               subscr_named_msg_event,
 477                               NULL,
 478                               NULL,
 479                               &topsrv.setup_port);
 480         if (res)
 481                 goto failed;
 482
 483         res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 484         if (res)
 485                 goto failed;
 486
 487         spin_unlock_bh(&topsrv.lock);
 488         return 0;
 489
 490 failed:
 491         err("Failed to create subscription service\n");
 492         tipc_detach(topsrv.user_ref);
 493         topsrv.user_ref = 0;
 494         spin_unlock_bh(&topsrv.lock);
 495         return res;
 496 }
 497
 498 void tipc_subscr_stop(void)
 499 {
 500         struct subscriber *subscriber;
 501         struct subscriber *subscriber_temp;
 502         spinlock_t *subscriber_lock;
 503
 504         if (topsrv.user_ref) {
 505                 tipc_deleteport(topsrv.setup_port);
 506                 list_for_each_entry_safe(subscriber, subscriber_temp,
 507                                          &topsrv.subscriber_list,
 508                                          subscriber_list) {
 509                         tipc_ref_lock(subscriber->ref);
 510                         subscriber_lock = subscriber->lock;
 511                         subscr_terminate(subscriber);
 512                         spin_unlock_bh(subscriber_lock);
 513                 }
 514                 tipc_detach(topsrv.user_ref);
 515                 topsrv.user_ref = 0;
 516         }
 517 }
 518
 519
 520 int tipc_ispublished(struct tipc_name const *name)
 521 {
 522         u32 domain = 0;
 523
 524         return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
 525 }
 526