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  * Redistributions of source code must retain the above copyright notice, this
  13  * list of conditions and the following disclaimer.
  14  * Redistributions in binary form must reproduce the above copyright notice,
  15  * this list of conditions and the following disclaimer in the documentation
  16  * and/or other materials provided with the distribution.
  17  * Neither the names of the copyright holders nor the names of its
  18  * contributors may be used to endorse or promote products derived from this
  19  * software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31  * POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include "core.h"
  35 #include "dbg.h"
  36 #include "subscr.h"
  37 #include "name_table.h"
  38 #include "ref.h"
  39
  40 /**
  41  * struct subscriber - TIPC network topology subscriber
  42  * @ref: object reference to subscriber object itself
  43  * @lock: pointer to spinlock controlling access to subscriber object
  44  * @subscriber_list: adjacent subscribers in top. server's list of subscribers
  45  * @subscription_list: list of subscription objects for this subscriber
  46  * @port_ref: object reference to port used to communicate with subscriber
  47  * @swap: indicates if subscriber uses opposite endianness in its messages
  48  */
  49
  50 struct subscriber {
  51         u32 ref;
  52         spinlock_t *lock;
  53         struct list_head subscriber_list;
  54         struct list_head subscription_list;
  55         u32 port_ref;
  56         int swap;
  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 inline u32 htohl(u32 in, int swap)
  87 {
  88         char *c = (char *)&in;
  89
  90         return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
  91 }
  92
  93 /**
  94  * subscr_send_event - send a message containing a tipc_event to the subscriber
  95  */
  96
  97 static void subscr_send_event(struct subscription *sub,
  98                               u32 found_lower,
  99                               u32 found_upper,
 100                               u32 event,
 101                               u32 port_ref,
 102                               u32 node)
 103 {
 104         struct iovec msg_sect;
 105
 106         msg_sect.iov_base = (void *)&sub->evt;
 107         msg_sect.iov_len = sizeof(struct tipc_event);
 108
 109         sub->evt.event = htohl(event, sub->owner->swap);
 110         sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
 111         sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
 112         sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
 113         sub->evt.port.node = htohl(node, sub->owner->swap);
 114         tipc_send(sub->owner->port_ref, 1, &msg_sect);
 115 }
 116
 117 /**
 118  * subscr_overlap - test for subscription overlap with the given values
 119  *
 120  * Returns 1 if there is overlap, otherwise 0.
 121  */
 122
 123 int subscr_overlap(struct subscription *sub,
 124                    u32 found_lower,
 125                    u32 found_upper)
 126
 127 {
 128         if (found_lower < sub->seq.lower)
 129                 found_lower = sub->seq.lower;
 130         if (found_upper > sub->seq.upper)
 131                 found_upper = sub->seq.upper;
 132         if (found_lower > found_upper)
 133                 return 0;
 134         return 1;
 135 }
 136
 137 /**
 138  * subscr_report_overlap - issue event if there is subscription overlap
 139  *
 140  * Protected by nameseq.lock in name_table.c
 141  */
 142
 143 void subscr_report_overlap(struct subscription *sub,
 144                            u32 found_lower,
 145                            u32 found_upper,
 146                            u32 event,
 147                            u32 port_ref,
 148                            u32 node,
 149                            int must)
 150 {
 151         dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
 152             sub->seq.upper, found_lower, found_upper);
 153         if (!subscr_overlap(sub, found_lower, found_upper))
 154                 return;
 155         if (!must && (sub->filter != TIPC_SUB_PORTS))
 156                 return;
 157         subscr_send_event(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 *)ref_lock(subscriber_ref);
 173         if (subscriber == NULL)
 174                 return;
 175
 176         /* Unlink subscription from name table */
 177
 178         nametbl_unsubscribe(sub);
 179
 180         /* Notify subscriber of timeout, then unlink subscription */
 181
 182         subscr_send_event(sub,
 183                           sub->evt.s.seq.lower,
 184                           sub->evt.s.seq.upper,
 185                           TIPC_SUBSCR_TIMEOUT,
 186                           0,
 187                           0);
 188         list_del(&sub->subscription_list);
 189
 190         /* Now destroy subscription */
 191
 192         ref_unlock(subscriber_ref);
 193         k_term_timer(&sub->timer);
 194         kfree(sub);
 195         atomic_dec(&topsrv.subscription_count);
 196 }
 197
 198 /**
 199  * subscr_terminate - terminate communication with a subscriber
 200  *
 201  * Called with subscriber locked.  Routine must temporarily release this lock
 202  * to enable subscription timeout routine(s) to finish without deadlocking;
 203  * the lock is then reclaimed to allow caller to release it upon return.
 204  * (This should work even in the unlikely event some other thread creates
 205  * a new object reference in the interim that uses this lock; this routine will
 206  * simply wait for it to be released, then claim it.)
 207  */
 208
 209 static void subscr_terminate(struct subscriber *subscriber)
 210 {
 211         struct subscription *sub;
 212         struct subscription *sub_temp;
 213
 214         /* Invalidate subscriber reference */
 215
 216         ref_discard(subscriber->ref);
 217         spin_unlock_bh(subscriber->lock);
 218
 219         /* Destroy any existing subscriptions for subscriber */
 220
 221         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 222                                  subscription_list) {
 223                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 224                         k_cancel_timer(&sub->timer);
 225                         k_term_timer(&sub->timer);
 226                 }
 227                 nametbl_unsubscribe(sub);
 228                 list_del(&sub->subscription_list);
 229                 dbg("Term: Removed sub %u,%u,%u from subscriber %x list\n",
 230                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 231                 kfree(sub);
 232                 atomic_dec(&topsrv.subscription_count);
 233         }
 234
 235         /* Sever connection to subscriber */
 236
 237         tipc_shutdown(subscriber->port_ref);
 238         tipc_deleteport(subscriber->port_ref);
 239
 240         /* Remove subscriber from topology server's subscriber list */
 241
 242         spin_lock_bh(&topsrv.lock);
 243         list_del(&subscriber->subscriber_list);
 244         spin_unlock_bh(&topsrv.lock);
 245
 246         /* Now destroy subscriber */
 247
 248         spin_lock_bh(subscriber->lock);
 249         kfree(subscriber);
 250 }
 251
 252 /**
 253  * subscr_subscribe - create subscription for subscriber
 254  *
 255  * Called with subscriber locked
 256  */
 257
 258 static void subscr_subscribe(struct tipc_subscr *s,
 259                              struct subscriber *subscriber)
 260 {
 261         struct subscription *sub;
 262
 263         /* Refuse subscription if global limit exceeded */
 264
 265         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 266                 warn("Failed: max %u subscriptions\n", tipc_max_subscriptions);
 267                 subscr_terminate(subscriber);
 268                 return;
 269         }
 270
 271         /* Allocate subscription object */
 272
 273         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 274         if (sub == NULL) {
 275                 warn("Memory squeeze; ignoring subscription\n");
 276                 subscr_terminate(subscriber);
 277                 return;
 278         }
 279
 280         /* Determine/update subscriber's endianness */
 281
 282         if ((s->filter == TIPC_SUB_PORTS) || (s->filter == TIPC_SUB_SERVICE))
 283                 subscriber->swap = 0;
 284         else
 285                 subscriber->swap = 1;
 286
 287         /* Initialize subscription object */
 288
 289         memset(sub, 0, sizeof(*sub));
 290         sub->seq.type = htohl(s->seq.type, subscriber->swap);
 291         sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
 292         sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
 293         sub->timeout = htohl(s->timeout, subscriber->swap);
 294         sub->filter = htohl(s->filter, subscriber->swap);
 295         if ((((sub->filter != TIPC_SUB_PORTS)
 296               && (sub->filter != TIPC_SUB_SERVICE)))
 297             || (sub->seq.lower > sub->seq.upper)) {
 298                 warn("Rejecting illegal subscription %u,%u,%u\n",
 299                      sub->seq.type, sub->seq.lower, sub->seq.upper);
 300                 kfree(sub);
 301                 subscr_terminate(subscriber);
 302                 return;
 303         }
 304         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 305         INIT_LIST_HEAD(&sub->subscription_list);
 306         INIT_LIST_HEAD(&sub->nameseq_list);
 307         list_add(&sub->subscription_list, &subscriber->subscription_list);
 308         atomic_inc(&topsrv.subscription_count);
 309         if (sub->timeout != TIPC_WAIT_FOREVER) {
 310                 k_init_timer(&sub->timer,
 311                              (Handler)subscr_timeout, (unsigned long)sub);
 312                 k_start_timer(&sub->timer, sub->timeout);
 313         }
 314         sub->owner = subscriber;
 315         nametbl_subscribe(sub);
 316 }
 317
 318 /**
 319  * subscr_conn_shutdown_event - handle termination request from subscriber
 320  */
 321
 322 static void subscr_conn_shutdown_event(void *usr_handle,
 323                                        u32 portref,
 324                                        struct sk_buff **buf,
 325                                        unsigned char const *data,
 326                                        unsigned int size,
 327                                        int reason)
 328 {
 329         struct subscriber *subscriber = ref_lock((u32)usr_handle);
 330         spinlock_t *subscriber_lock;
 331
 332         if (subscriber == NULL)
 333                 return;
 334
 335         subscriber_lock = subscriber->lock;
 336         subscr_terminate(subscriber);
 337         spin_unlock_bh(subscriber_lock);
 338 }
 339
 340 /**
 341  * subscr_conn_msg_event - handle new subscription request from subscriber
 342  */
 343
 344 static void subscr_conn_msg_event(void *usr_handle,
 345                                   u32 port_ref,
 346                                   struct sk_buff **buf,
 347                                   const unchar *data,
 348                                   u32 size)
 349 {
 350         struct subscriber *subscriber = ref_lock((u32)usr_handle);
 351         spinlock_t *subscriber_lock;
 352
 353         if (subscriber == NULL)
 354                 return;
 355
 356         subscriber_lock = subscriber->lock;
 357         if (size != sizeof(struct tipc_subscr))
 358                 subscr_terminate(subscriber);
 359         else
 360                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 361
 362         spin_unlock_bh(subscriber_lock);
 363 }
 364
 365 /**
 366  * subscr_named_msg_event - handle request to establish a new subscriber
 367  */
 368
 369 static void subscr_named_msg_event(void *usr_handle,
 370                                    u32 port_ref,
 371                                    struct sk_buff **buf,
 372                                    const unchar *data,
 373                                    u32 size,
 374                                    u32 importance,
 375                                    struct tipc_portid const *orig,
 376                                    struct tipc_name_seq const *dest)
 377 {
 378         struct subscriber *subscriber;
 379         struct iovec msg_sect = {0, 0};
 380         spinlock_t *subscriber_lock;
 381
 382         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 383             orig->node, tipc_own_addr);
 384         if (size && (size != sizeof(struct tipc_subscr))) {
 385                 warn("Received tipc_subscr of invalid size\n");
 386                 return;
 387         }
 388
 389         /* Create subscriber object */
 390
 391         subscriber = kmalloc(sizeof(struct subscriber), GFP_ATOMIC);
 392         if (subscriber == NULL) {
 393                 warn("Memory squeeze; ignoring subscriber setup\n");
 394                 return;
 395         }
 396         memset(subscriber, 0, sizeof(struct subscriber));
 397         INIT_LIST_HEAD(&subscriber->subscription_list);
 398         INIT_LIST_HEAD(&subscriber->subscriber_list);
 399         subscriber->ref = ref_acquire(subscriber, &subscriber->lock);
 400         if (subscriber->ref == 0) {
 401                 warn("Failed to acquire subscriber reference\n");
 402                 kfree(subscriber);
 403                 return;
 404         }
 405
 406         /* Establish a connection to subscriber */
 407
 408         tipc_createport(topsrv.user_ref,
 409                         (void *)subscriber->ref,
 410                         importance,
 411                         0,
 412                         0,
 413                         subscr_conn_shutdown_event,
 414                         0,
 415                         0,
 416                         subscr_conn_msg_event,
 417                         0,
 418                         &subscriber->port_ref);
 419         if (subscriber->port_ref == 0) {
 420                 warn("Memory squeeze; failed to create subscription port\n");
 421                 ref_discard(subscriber->ref);
 422                 kfree(subscriber);
 423                 return;
 424         }
 425         tipc_connect2port(subscriber->port_ref, orig);
 426
 427
 428         /* Add subscriber to topology server's subscriber list */
 429
 430         ref_lock(subscriber->ref);
 431         spin_lock_bh(&topsrv.lock);
 432         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 433         spin_unlock_bh(&topsrv.lock);
 434
 435         /*
 436          * Subscribe now if message contains a subscription,
 437          * otherwise send an empty response to complete connection handshaking
 438          */
 439
 440         subscriber_lock = subscriber->lock;
 441         if (size)
 442                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
 443         else
 444                 tipc_send(subscriber->port_ref, 1, &msg_sect);
 445
 446         spin_unlock_bh(subscriber_lock);
 447 }
 448
 449 int subscr_start(void)
 450 {
 451         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 452         int res = -1;
 453
 454         memset(&topsrv, 0, sizeof (topsrv));
 455         topsrv.lock = SPIN_LOCK_UNLOCKED;
 456         INIT_LIST_HEAD(&topsrv.subscriber_list);
 457
 458         spin_lock_bh(&topsrv.lock);
 459         res = tipc_attach(&topsrv.user_ref, 0, 0);
 460         if (res) {
 461                 spin_unlock_bh(&topsrv.lock);
 462                 return res;
 463         }
 464
 465         res = tipc_createport(topsrv.user_ref,
 466                               0,
 467                               TIPC_CRITICAL_IMPORTANCE,
 468                               0,
 469                               0,
 470                               0,
 471                               0,
 472                               subscr_named_msg_event,
 473                               0,
 474                               0,
 475                               &topsrv.setup_port);
 476         if (res)
 477                 goto failed;
 478
 479         res = nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 480         if (res)
 481                 goto failed;
 482
 483         spin_unlock_bh(&topsrv.lock);
 484         return 0;
 485
 486 failed:
 487         err("Unable to create subscription service\n");
 488         tipc_detach(topsrv.user_ref);
 489         topsrv.user_ref = 0;
 490         spin_unlock_bh(&topsrv.lock);
 491         return res;
 492 }
 493
 494 void subscr_stop(void)
 495 {
 496         struct subscriber *subscriber;
 497         struct subscriber *subscriber_temp;
 498         spinlock_t *subscriber_lock;
 499
 500         if (topsrv.user_ref) {
 501                 tipc_deleteport(topsrv.setup_port);
 502                 list_for_each_entry_safe(subscriber, subscriber_temp,
 503                                          &topsrv.subscriber_list,
 504                                          subscriber_list) {
 505                         ref_lock(subscriber->ref);
 506                         subscriber_lock = subscriber->lock;
 507                         subscr_terminate(subscriber);
 508                         spin_unlock_bh(subscriber_lock);
 509                 }
 510                 tipc_detach(topsrv.user_ref);
 511                 topsrv.user_ref = 0;
 512         }
 513 }
 514
 515
 516 int tipc_ispublished(struct tipc_name const *name)
 517 {
 518         u32 domain = 0;
 519
 520         return(nametbl_translate(name->type, name->instance,&domain) != 0);
 521 }
 522