SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/tipc/subscr.c

   1 /*
   2  * net/tipc/subscr.c: TIPC subscription service
   3  *
   4  * Copyright (c) 2003-2005, Ericsson Research Canada
   5  * Copyright (c) 2005, Wind River Systems
   6  * Copyright (c) 2005-2006, Ericsson AB
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the names of the copyright holders nor the names of its
  18  *    contributors may be used to endorse or promote products derived from
  19  *    this software without specific prior written permission.
  20  *
  21  * Alternatively, this software may be distributed under the terms of the
  22  * GNU General Public License ("GPL") version 2 as published by the Free
  23  * Software Foundation.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  26  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  29  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35  * POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "core.h"
  39 #include "dbg.h"
  40 #include "subscr.h"
  41 #include "name_table.h"
  42 #include "ref.h"
  43
  44 /**
  45  * struct subscriber - TIPC network topology subscriber
  46  * @ref: object reference to subscriber object itself
  47  * @lock: pointer to spinlock controlling access to subscriber object
  48  * @subscriber_list: adjacent subscribers in top. server's list of subscribers
  49  * @subscription_list: list of subscription objects for this subscriber
  50  * @port_ref: object reference to port used to communicate with subscriber
  51  * @swap: indicates if subscriber uses opposite endianness in its messages
  52  */
  53
  54 struct subscriber {
  55         u32 ref;
  56         spinlock_t *lock;
  57         struct list_head subscriber_list;
  58         struct list_head subscription_list;
  59         u32 port_ref;
  60         int swap;
  61 };
  62
  63 /**
  64  * struct top_srv - TIPC network topology subscription service
  65  * @user_ref: TIPC userid of subscription service
  66  * @setup_port: reference to TIPC port that handles subscription requests
  67  * @subscription_count: number of active subscriptions (not subscribers!)
  68  * @subscriber_list: list of ports subscribing to service
  69  * @lock: spinlock govering access to subscriber list
  70  */
  71
  72 struct top_srv {
  73         u32 user_ref;
  74         u32 setup_port;
  75         atomic_t subscription_count;
  76         struct list_head subscriber_list;
  77         spinlock_t lock;
  78 };
  79
  80 static struct top_srv topsrv = { 0 };
  81
  82 /**
  83  * htohl - convert value to endianness used by destination
  84  * @in: value to convert
  85  * @swap: non-zero if endianness must be reversed
  86  *
  87  * Returns converted value
  88  */
  89
  90 static inline u32 htohl(u32 in, int swap)
  91 {
  92         char *c = (char *)&in;
  93
  94         return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
  95 }
  96
  97 /**
  98  * subscr_send_event - send a message containing a tipc_event to the subscriber
  99  */
 100
 101 static void subscr_send_event(struct subscription *sub,
 102                               u32 found_lower,
 103                               u32 found_upper,
 104                               u32 event,
 105                               u32 port_ref,
 106                               u32 node)
 107 {
 108         struct iovec msg_sect;
 109
 110         msg_sect.iov_base = (void *)&sub->evt;
 111         msg_sect.iov_len = sizeof(struct tipc_event);
 112
 113         sub->evt.event = htohl(event, sub->owner->swap);
 114         sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
 115         sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
 116         sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
 117         sub->evt.port.node = htohl(node, sub->owner->swap);
 118         tipc_send(sub->owner->port_ref, 1, &msg_sect);
 119 }
 120
 121 /**
 122  * subscr_overlap - test for subscription overlap with the given values
 123  *
 124  * Returns 1 if there is overlap, otherwise 0.
 125  */
 126
 127 int subscr_overlap(struct subscription *sub,
 128                    u32 found_lower,
 129                    u32 found_upper)
 130
 131 {
 132         if (found_lower < sub->seq.lower)
 133                 found_lower = sub->seq.lower;
 134         if (found_upper > sub->seq.upper)
 135                 found_upper = sub->seq.upper;
 136         if (found_lower > found_upper)
 137                 return 0;
 138         return 1;
 139 }
 140
 141 /**
 142  * subscr_report_overlap - issue event if there is subscription overlap
 143  *
 144  * Protected by nameseq.lock in name_table.c
 145  */
 146
 147 void subscr_report_overlap(struct subscription *sub,
 148                            u32 found_lower,
 149                            u32 found_upper,
 150                            u32 event,
 151                            u32 port_ref,
 152                            u32 node,
 153                            int must)
 154 {
 155         dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
 156             sub->seq.upper, found_lower, found_upper);
 157         if (!subscr_overlap(sub, found_lower, found_upper))
 158                 return;
 159         if (!must && (sub->filter != TIPC_SUB_PORTS))
 160                 return;
 161         subscr_send_event(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 *)ref_lock(subscriber_ref);
 177         if (subscriber == NULL)
 178                 return;
 179
 180         /* Unlink subscription from name table */
 181
 182         nametbl_unsubscribe(sub);
 183
 184         /* Notify subscriber of timeout, then unlink subscription */
 185
 186         subscr_send_event(sub,
 187                           sub->evt.s.seq.lower,
 188                           sub->evt.s.seq.upper,
 189                           TIPC_SUBSCR_TIMEOUT,
 190                           0,
 191                           0);
 192         list_del(&sub->subscription_list);
 193
 194         /* Now destroy subscription */
 195
 196         ref_unlock(subscriber_ref);
 197         k_term_timer(&sub->timer);
 198         kfree(sub);
 199         atomic_dec(&topsrv.subscription_count);
 200 }
 201
 202 /**
 203  * subscr_terminate - terminate communication with a subscriber
 204  *
 205  * Called with subscriber locked.  Routine must temporarily release this lock
 206  * to enable subscription timeout routine(s) to finish without deadlocking;
 207  * the lock is then reclaimed to allow caller to release it upon return.
 208  * (This should work even in the unlikely event some other thread creates
 209  * a new object reference in the interim that uses this lock; this routine will
 210  * simply wait for it to be released, then claim it.)
 211  */
 212
 213 static void subscr_terminate(struct subscriber *subscriber)
 214 {
 215         struct subscription *sub;
 216         struct subscription *sub_temp;
 217
 218         /* Invalidate subscriber reference */
 219
 220         ref_discard(subscriber->ref);
 221         spin_unlock_bh(subscriber->lock);
 222
 223         /* Destroy any existing subscriptions for subscriber */
 224
 225         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 226                                  subscription_list) {
 227                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 228                         k_cancel_timer(&sub->timer);
 229                         k_term_timer(&sub->timer);
 230                 }
 231                 nametbl_unsubscribe(sub);
 232                 list_del(&sub->subscription_list);
 233                 dbg("Term: Removed sub %u,%u,%u from subscriber %x list\n",
 234                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 235                 kfree(sub);
 236                 atomic_dec(&topsrv.subscription_count);
 237         }
 238
 239         /* Sever connection to subscriber */
 240
 241         tipc_shutdown(subscriber->port_ref);
 242         tipc_deleteport(subscriber->port_ref);
 243
 244         /* Remove subscriber from topology server's subscriber list */
 245
 246         spin_lock_bh(&topsrv.lock);
 247         list_del(&subscriber->subscriber_list);
 248         spin_unlock_bh(&topsrv.lock);
 249
 250         /* Now destroy subscriber */
 251
 252         spin_lock_bh(subscriber->lock);
 253         kfree(subscriber);
 254 }
 255
 256 /**
 257  * subscr_subscribe - create subscription for subscriber
 258  *
 259  * Called with subscriber locked
 260  */
 261
 262 static void subscr_subscribe(struct tipc_subscr *s,
 263                              struct subscriber *subscriber)
 264 {
 265         struct subscription *sub;
 266
 267         /* Refuse subscription if global limit exceeded */
 268
 269         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 270                 warn("Failed: max %u subscriptions\n", 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 == NULL) {
 279                 warn("Memory squeeze; ignoring subscription\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("Rejecting illegal subscription %u,%u,%u\n",
 303                      sub->seq.type, sub->seq.lower, sub->seq.upper);
 304                 kfree(sub);
 305                 subscr_terminate(subscriber);
 306                 return;
 307         }
 308         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 309         INIT_LIST_HEAD(&sub->subscription_list);
 310         INIT_LIST_HEAD(&sub->nameseq_list);
 311         list_add(&sub->subscription_list, &subscriber->subscription_list);
 312         atomic_inc(&topsrv.subscription_count);
 313         if (sub->timeout != TIPC_WAIT_FOREVER) {
 314                 k_init_timer(&sub->timer,
 315                              (Handler)subscr_timeout, (unsigned long)sub);
 316                 k_start_timer(&sub->timer, sub->timeout);
 317         }
 318         sub->owner = subscriber;
 319         nametbl_subscribe(sub);
 320 }
 321
 322 /**
 323  * subscr_conn_shutdown_event - handle termination request from subscriber
 324  */
 325
 326 static void subscr_conn_shutdown_event(void *usr_handle,
 327                                        u32 portref,
 328                                        struct sk_buff **buf,
 329                                        unsigned char const *data,
 330                                        unsigned int size,
 331                                        int reason)
 332 {
 333         struct subscriber *subscriber = ref_lock((u32)usr_handle);
 334         spinlock_t *subscriber_lock;
 335
 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 = ref_lock((u32)usr_handle);
 355         spinlock_t *subscriber_lock;
 356
 357         if (subscriber == NULL)
 358                 return;
 359
 360         subscriber_lock = subscriber->lock;
 361         if (size != sizeof(struct tipc_subscr))
 362                 subscr_terminate(subscriber);
 363         else
 364                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 365
 366         spin_unlock_bh(subscriber_lock);
 367 }
 368
 369 /**
 370  * subscr_named_msg_event - handle request to establish a new subscriber
 371  */
 372
 373 static void subscr_named_msg_event(void *usr_handle,
 374                                    u32 port_ref,
 375                                    struct sk_buff **buf,
 376                                    const unchar *data,
 377                                    u32 size,
 378                                    u32 importance,
 379                                    struct tipc_portid const *orig,
 380                                    struct tipc_name_seq const *dest)
 381 {
 382         struct subscriber *subscriber;
 383         struct iovec msg_sect = {0, 0};
 384         spinlock_t *subscriber_lock;
 385
 386         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 387             orig->node, tipc_own_addr);
 388         if (size && (size != sizeof(struct tipc_subscr))) {
 389                 warn("Received tipc_subscr of invalid size\n");
 390                 return;
 391         }
 392
 393         /* Create subscriber object */
 394
 395         subscriber = kmalloc(sizeof(struct subscriber), GFP_ATOMIC);
 396         if (subscriber == NULL) {
 397                 warn("Memory squeeze; ignoring subscriber setup\n");
 398                 return;
 399         }
 400         memset(subscriber, 0, sizeof(struct subscriber));
 401         INIT_LIST_HEAD(&subscriber->subscription_list);
 402         INIT_LIST_HEAD(&subscriber->subscriber_list);
 403         subscriber->ref = ref_acquire(subscriber, &subscriber->lock);
 404         if (subscriber->ref == 0) {
 405                 warn("Failed to acquire subscriber reference\n");
 406                 kfree(subscriber);
 407                 return;
 408         }
 409
 410         /* Establish a connection to subscriber */
 411
 412         tipc_createport(topsrv.user_ref,
 413                         (void *)subscriber->ref,
 414                         importance,
 415                         0,
 416                         0,
 417                         subscr_conn_shutdown_event,
 418                         0,
 419                         0,
 420                         subscr_conn_msg_event,
 421                         0,
 422                         &subscriber->port_ref);
 423         if (subscriber->port_ref == 0) {
 424                 warn("Memory squeeze; failed to create subscription port\n");
 425                 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         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 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         topsrv.lock = SPIN_LOCK_UNLOCKED;
 460         INIT_LIST_HEAD(&topsrv.subscriber_list);
 461
 462         spin_lock_bh(&topsrv.lock);
 463         res = tipc_attach(&topsrv.user_ref, 0, 0);
 464         if (res) {
 465                 spin_unlock_bh(&topsrv.lock);
 466                 return res;
 467         }
 468
 469         res = tipc_createport(topsrv.user_ref,
 470                               0,
 471                               TIPC_CRITICAL_IMPORTANCE,
 472                               0,
 473                               0,
 474                               0,
 475                               0,
 476                               subscr_named_msg_event,
 477                               0,
 478                               0,
 479                               &topsrv.setup_port);
 480         if (res)
 481                 goto failed;
 482
 483         res = 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 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                         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(nametbl_translate(name->type, name->instance,&domain) != 0);
 525 }
 526