Pileus Git - ~andy/linux/blob - net/tipc/subscr.c

   1 /*
   2  * net/tipc/subscr.c: TIPC network topology service
   3  *
   4  * Copyright (c) 2000-2006, Ericsson AB
   5  * Copyright (c) 2005-2007, 2010-2013, 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 "name_table.h"
  39 #include "port.h"
  40 #include "subscr.h"
  41
  42 /**
  43  * struct tipc_subscriber - TIPC network topology subscriber
  44  * @conid: connection identifier to server connecting to subscriber
  45  * @lock: controll access to subscriber
  46  * @subscription_list: list of subscription objects for this subscriber
  47  */
  48 struct tipc_subscriber {
  49         int conid;
  50         spinlock_t lock;
  51         struct list_head subscription_list;
  52 };
  53
  54 static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
  55                                   void *usr_data, void *buf, size_t len);
  56 static void *subscr_named_msg_event(int conid);
  57 static void subscr_conn_shutdown_event(int conid, void *usr_data);
  58
  59 static atomic_t subscription_count = ATOMIC_INIT(0);
  60
  61 static struct sockaddr_tipc topsrv_addr __read_mostly = {
  62         .family                 = AF_TIPC,
  63         .addrtype               = TIPC_ADDR_NAMESEQ,
  64         .addr.nameseq.type      = TIPC_TOP_SRV,
  65         .addr.nameseq.lower     = TIPC_TOP_SRV,
  66         .addr.nameseq.upper     = TIPC_TOP_SRV,
  67         .scope                  = TIPC_NODE_SCOPE
  68 };
  69
  70 static struct tipc_server topsrv __read_mostly = {
  71         .saddr                  = &topsrv_addr,
  72         .imp                    = TIPC_CRITICAL_IMPORTANCE,
  73         .type                   = SOCK_SEQPACKET,
  74         .max_rcvbuf_size        = sizeof(struct tipc_subscr),
  75         .name                   = "topology_server",
  76         .tipc_conn_recvmsg      = subscr_conn_msg_event,
  77         .tipc_conn_new          = subscr_named_msg_event,
  78         .tipc_conn_shutdown     = subscr_conn_shutdown_event,
  79 };
  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 static u32 htohl(u32 in, int swap)
  89 {
  90         return swap ? swab32(in) : in;
  91 }
  92
  93 static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
  94                               u32 found_upper, u32 event, u32 port_ref,
  95                               u32 node)
  96 {
  97         struct tipc_subscriber *subscriber = sub->subscriber;
  98         struct kvec msg_sect;
  99         int ret;
 100
 101         msg_sect.iov_base = (void *)&sub->evt;
 102         msg_sect.iov_len = sizeof(struct tipc_event);
 103
 104         sub->evt.event = htohl(event, sub->swap);
 105         sub->evt.found_lower = htohl(found_lower, sub->swap);
 106         sub->evt.found_upper = htohl(found_upper, sub->swap);
 107         sub->evt.port.ref = htohl(port_ref, sub->swap);
 108         sub->evt.port.node = htohl(node, sub->swap);
 109         ret = tipc_conn_sendmsg(&topsrv, subscriber->conid, NULL,
 110                                 msg_sect.iov_base, msg_sect.iov_len);
 111         if (ret < 0)
 112                 pr_err("Sending subscription event failed, no memory\n");
 113 }
 114
 115 /**
 116  * tipc_subscr_overlap - test for subscription overlap with the given values
 117  *
 118  * Returns 1 if there is overlap, otherwise 0.
 119  */
 120 int tipc_subscr_overlap(struct tipc_subscription *sub,
 121                         u32 found_lower,
 122                         u32 found_upper)
 123
 124 {
 125         if (found_lower < sub->seq.lower)
 126                 found_lower = sub->seq.lower;
 127         if (found_upper > sub->seq.upper)
 128                 found_upper = sub->seq.upper;
 129         if (found_lower > found_upper)
 130                 return 0;
 131         return 1;
 132 }
 133
 134 /**
 135  * tipc_subscr_report_overlap - issue event if there is subscription overlap
 136  *
 137  * Protected by nameseq.lock in name_table.c
 138  */
 139 void tipc_subscr_report_overlap(struct tipc_subscription *sub,
 140                                 u32 found_lower,
 141                                 u32 found_upper,
 142                                 u32 event,
 143                                 u32 port_ref,
 144                                 u32 node,
 145                                 int must)
 146 {
 147         if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 148                 return;
 149         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 150                 return;
 151
 152         subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
 153 }
 154
 155 static void subscr_timeout(struct tipc_subscription *sub)
 156 {
 157         struct tipc_subscriber *subscriber = sub->subscriber;
 158
 159         /* The spin lock per subscriber is used to protect its members */
 160         spin_lock_bh(&subscriber->lock);
 161
 162         /* Validate if the connection related to the subscriber is
 163          * closed (in case subscriber is terminating)
 164          */
 165         if (subscriber->conid == 0) {
 166                 spin_unlock_bh(&subscriber->lock);
 167                 return;
 168         }
 169
 170         /* Validate timeout (in case subscription is being cancelled) */
 171         if (sub->timeout == TIPC_WAIT_FOREVER) {
 172                 spin_unlock_bh(&subscriber->lock);
 173                 return;
 174         }
 175
 176         /* Unlink subscription from name table */
 177         tipc_nametbl_unsubscribe(sub);
 178
 179         /* Unlink subscription from subscriber */
 180         list_del(&sub->subscription_list);
 181
 182         spin_unlock_bh(&subscriber->lock);
 183
 184         /* Notify subscriber of timeout */
 185         subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 186                           TIPC_SUBSCR_TIMEOUT, 0, 0);
 187
 188         /* Now destroy subscription */
 189         k_term_timer(&sub->timer);
 190         kfree(sub);
 191         atomic_dec(&subscription_count);
 192 }
 193
 194 /**
 195  * subscr_del - delete a subscription within a subscription list
 196  *
 197  * Called with subscriber lock held.
 198  */
 199 static void subscr_del(struct tipc_subscription *sub)
 200 {
 201         tipc_nametbl_unsubscribe(sub);
 202         list_del(&sub->subscription_list);
 203         kfree(sub);
 204         atomic_dec(&subscription_count);
 205 }
 206
 207 /**
 208  * subscr_terminate - terminate communication with a subscriber
 209  *
 210  * Note: Must call it in process context since it might sleep.
 211  */
 212 static void subscr_terminate(struct tipc_subscriber *subscriber)
 213 {
 214         tipc_conn_terminate(&topsrv, subscriber->conid);
 215 }
 216
 217 static void subscr_release(struct tipc_subscriber *subscriber)
 218 {
 219         struct tipc_subscription *sub;
 220         struct tipc_subscription *sub_temp;
 221
 222         spin_lock_bh(&subscriber->lock);
 223
 224         /* Invalidate subscriber reference */
 225         subscriber->conid = 0;
 226
 227         /* Destroy any existing subscriptions for subscriber */
 228         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 229                                  subscription_list) {
 230                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 231                         spin_unlock_bh(&subscriber->lock);
 232                         k_cancel_timer(&sub->timer);
 233                         k_term_timer(&sub->timer);
 234                         spin_lock_bh(&subscriber->lock);
 235                 }
 236                 subscr_del(sub);
 237         }
 238         spin_unlock_bh(&subscriber->lock);
 239
 240         /* Now destroy subscriber */
 241         kfree(subscriber);
 242 }
 243
 244 /**
 245  * subscr_cancel - handle subscription cancellation request
 246  *
 247  * Called with subscriber lock held. Routine must temporarily release lock
 248  * to enable the subscription timeout routine to finish without deadlocking;
 249  * the lock is then reclaimed to allow caller to release it upon return.
 250  *
 251  * Note that fields of 's' use subscriber's endianness!
 252  */
 253 static void subscr_cancel(struct tipc_subscr *s,
 254                           struct tipc_subscriber *subscriber)
 255 {
 256         struct tipc_subscription *sub;
 257         struct tipc_subscription *sub_temp;
 258         int found = 0;
 259
 260         /* Find first matching subscription, exit if not found */
 261         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 262                                  subscription_list) {
 263                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 264                         found = 1;
 265                         break;
 266                 }
 267         }
 268         if (!found)
 269                 return;
 270
 271         /* Cancel subscription timer (if used), then delete subscription */
 272         if (sub->timeout != TIPC_WAIT_FOREVER) {
 273                 sub->timeout = TIPC_WAIT_FOREVER;
 274                 spin_unlock_bh(&subscriber->lock);
 275                 k_cancel_timer(&sub->timer);
 276                 k_term_timer(&sub->timer);
 277                 spin_lock_bh(&subscriber->lock);
 278         }
 279         subscr_del(sub);
 280 }
 281
 282 /**
 283  * subscr_subscribe - create subscription for subscriber
 284  *
 285  * Called with subscriber lock held.
 286  */
 287 static struct tipc_subscription *subscr_subscribe(struct tipc_subscr *s,
 288                                              struct tipc_subscriber *subscriber)
 289 {
 290         struct tipc_subscription *sub;
 291         int swap;
 292
 293         /* Determine subscriber's endianness */
 294         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 295
 296         /* Detect & process a subscription cancellation request */
 297         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 298                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 299                 subscr_cancel(s, subscriber);
 300                 return NULL;
 301         }
 302
 303         /* Refuse subscription if global limit exceeded */
 304         if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 305                 pr_warn("Subscription rejected, limit reached (%u)\n",
 306                         TIPC_MAX_SUBSCRIPTIONS);
 307                 subscr_terminate(subscriber);
 308                 return NULL;
 309         }
 310
 311         /* Allocate subscription object */
 312         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 313         if (!sub) {
 314                 pr_warn("Subscription rejected, no memory\n");
 315                 subscr_terminate(subscriber);
 316                 return NULL;
 317         }
 318
 319         /* Initialize subscription object */
 320         sub->seq.type = htohl(s->seq.type, swap);
 321         sub->seq.lower = htohl(s->seq.lower, swap);
 322         sub->seq.upper = htohl(s->seq.upper, swap);
 323         sub->timeout = htohl(s->timeout, swap);
 324         sub->filter = htohl(s->filter, swap);
 325         if ((!(sub->filter & TIPC_SUB_PORTS) ==
 326              !(sub->filter & TIPC_SUB_SERVICE)) ||
 327             (sub->seq.lower > sub->seq.upper)) {
 328                 pr_warn("Subscription rejected, illegal request\n");
 329                 kfree(sub);
 330                 subscr_terminate(subscriber);
 331                 return NULL;
 332         }
 333         INIT_LIST_HEAD(&sub->nameseq_list);
 334         list_add(&sub->subscription_list, &subscriber->subscription_list);
 335         sub->subscriber = subscriber;
 336         sub->swap = swap;
 337         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 338         atomic_inc(&subscription_count);
 339         if (sub->timeout != TIPC_WAIT_FOREVER) {
 340                 k_init_timer(&sub->timer,
 341                              (Handler)subscr_timeout, (unsigned long)sub);
 342                 k_start_timer(&sub->timer, sub->timeout);
 343         }
 344
 345         return sub;
 346 }
 347
 348 /* Handle one termination request for the subscriber */
 349 static void subscr_conn_shutdown_event(int conid, void *usr_data)
 350 {
 351         subscr_release((struct tipc_subscriber *)usr_data);
 352 }
 353
 354 /* Handle one request to create a new subscription for the subscriber */
 355 static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
 356                                   void *usr_data, void *buf, size_t len)
 357 {
 358         struct tipc_subscriber *subscriber = usr_data;
 359         struct tipc_subscription *sub;
 360
 361         spin_lock_bh(&subscriber->lock);
 362         sub = subscr_subscribe((struct tipc_subscr *)buf, subscriber);
 363         if (sub)
 364                 tipc_nametbl_subscribe(sub);
 365         spin_unlock_bh(&subscriber->lock);
 366 }
 367
 368
 369 /* Handle one request to establish a new subscriber */
 370 static void *subscr_named_msg_event(int conid)
 371 {
 372         struct tipc_subscriber *subscriber;
 373
 374         /* Create subscriber object */
 375         subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
 376         if (subscriber == NULL) {
 377                 pr_warn("Subscriber rejected, no memory\n");
 378                 return NULL;
 379         }
 380         INIT_LIST_HEAD(&subscriber->subscription_list);
 381         subscriber->conid = conid;
 382         spin_lock_init(&subscriber->lock);
 383
 384         return (void *)subscriber;
 385 }
 386
 387 int tipc_subscr_start(void)
 388 {
 389         return tipc_server_start(&topsrv);
 390 }
 391
 392 void tipc_subscr_stop(void)
 393 {
 394         tipc_server_stop(&topsrv);
 395 }