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 "subscr.h"
  40
  41 /**
  42  * struct tipc_subscriber - TIPC network topology subscriber
  43  * @conid: connection identifier to server connecting to subscriber
  44  * @lock: control access to subscriber
  45  * @subscription_list: list of subscription objects for this subscriber
  46  */
  47 struct tipc_subscriber {
  48         int conid;
  49         spinlock_t lock;
  50         struct list_head subscription_list;
  51 };
  52
  53 /**
  54  * htohl - convert value to endianness used by destination
  55  * @in: value to convert
  56  * @swap: non-zero if endianness must be reversed
  57  *
  58  * Returns converted value
  59  */
  60 static u32 htohl(u32 in, int swap)
  61 {
  62         return swap ? swab32(in) : in;
  63 }
  64
  65 static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
  66                               u32 found_upper, u32 event, u32 port_ref,
  67                               u32 node)
  68 {
  69         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
  70         struct tipc_subscriber *subscriber = sub->subscriber;
  71         struct kvec msg_sect;
  72
  73         msg_sect.iov_base = (void *)&sub->evt;
  74         msg_sect.iov_len = sizeof(struct tipc_event);
  75         sub->evt.event = htohl(event, sub->swap);
  76         sub->evt.found_lower = htohl(found_lower, sub->swap);
  77         sub->evt.found_upper = htohl(found_upper, sub->swap);
  78         sub->evt.port.ref = htohl(port_ref, sub->swap);
  79         sub->evt.port.node = htohl(node, sub->swap);
  80         tipc_conn_sendmsg(tn->topsrv, subscriber->conid, NULL,
  81                           msg_sect.iov_base, msg_sect.iov_len);
  82 }
  83
  84 /**
  85  * tipc_subscr_overlap - test for subscription overlap with the given values
  86  *
  87  * Returns 1 if there is overlap, otherwise 0.
  88  */
  89 int tipc_subscr_overlap(struct tipc_subscription *sub, u32 found_lower,
  90                         u32 found_upper)
  91 {
  92         if (found_lower < sub->seq.lower)
  93                 found_lower = sub->seq.lower;
  94         if (found_upper > sub->seq.upper)
  95                 found_upper = sub->seq.upper;
  96         if (found_lower > found_upper)
  97                 return 0;
  98         return 1;
  99 }
 100
 101 /**
 102  * tipc_subscr_report_overlap - issue event if there is subscription overlap
 103  *
 104  * Protected by nameseq.lock in name_table.c
 105  */
 106 void tipc_subscr_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 107                                 u32 found_upper, u32 event, u32 port_ref,
 108                                 u32 node, int must)
 109 {
 110         if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 111                 return;
 112         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 113                 return;
 114
 115         subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
 116 }
 117
 118 static void subscr_timeout(unsigned long data)
 119 {
 120         struct tipc_subscription *sub = (struct tipc_subscription *)data;
 121         struct tipc_subscriber *subscriber = sub->subscriber;
 122         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 123
 124         /* The spin lock per subscriber is used to protect its members */
 125         spin_lock_bh(&subscriber->lock);
 126
 127         /* Validate timeout (in case subscription is being cancelled) */
 128         if (sub->timeout == TIPC_WAIT_FOREVER) {
 129                 spin_unlock_bh(&subscriber->lock);
 130                 return;
 131         }
 132
 133         /* Unlink subscription from name table */
 134         tipc_nametbl_unsubscribe(sub);
 135
 136         /* Unlink subscription from subscriber */
 137         list_del(&sub->subscription_list);
 138
 139         spin_unlock_bh(&subscriber->lock);
 140
 141         /* Notify subscriber of timeout */
 142         subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 143                           TIPC_SUBSCR_TIMEOUT, 0, 0);
 144
 145         /* Now destroy subscription */
 146         kfree(sub);
 147         atomic_dec(&tn->subscription_count);
 148 }
 149
 150 /**
 151  * subscr_del - delete a subscription within a subscription list
 152  *
 153  * Called with subscriber lock held.
 154  */
 155 static void subscr_del(struct tipc_subscription *sub)
 156 {
 157         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 158
 159         tipc_nametbl_unsubscribe(sub);
 160         list_del(&sub->subscription_list);
 161         kfree(sub);
 162         atomic_dec(&tn->subscription_count);
 163 }
 164
 165 /**
 166  * subscr_terminate - terminate communication with a subscriber
 167  *
 168  * Note: Must call it in process context since it might sleep.
 169  */
 170 static void subscr_terminate(struct tipc_subscription *sub)
 171 {
 172         struct tipc_subscriber *subscriber = sub->subscriber;
 173         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 174
 175         tipc_conn_terminate(tn->topsrv, subscriber->conid);
 176 }
 177
 178 static void subscr_release(struct tipc_subscriber *subscriber)
 179 {
 180         struct tipc_subscription *sub;
 181         struct tipc_subscription *sub_temp;
 182
 183         spin_lock_bh(&subscriber->lock);
 184
 185         /* Destroy any existing subscriptions for subscriber */
 186         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 187                                  subscription_list) {
 188                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 189                         spin_unlock_bh(&subscriber->lock);
 190                         del_timer_sync(&sub->timer);
 191                         spin_lock_bh(&subscriber->lock);
 192                 }
 193                 subscr_del(sub);
 194         }
 195         spin_unlock_bh(&subscriber->lock);
 196
 197         /* Now destroy subscriber */
 198         kfree(subscriber);
 199 }
 200
 201 /**
 202  * subscr_cancel - handle subscription cancellation request
 203  *
 204  * Called with subscriber lock held. Routine must temporarily release lock
 205  * to enable the subscription timeout routine to finish without deadlocking;
 206  * the lock is then reclaimed to allow caller to release it upon return.
 207  *
 208  * Note that fields of 's' use subscriber's endianness!
 209  */
 210 static void subscr_cancel(struct tipc_subscr *s,
 211                           struct tipc_subscriber *subscriber)
 212 {
 213         struct tipc_subscription *sub;
 214         struct tipc_subscription *sub_temp;
 215         int found = 0;
 216
 217         /* Find first matching subscription, exit if not found */
 218         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 219                                  subscription_list) {
 220                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 221                         found = 1;
 222                         break;
 223                 }
 224         }
 225         if (!found)
 226                 return;
 227
 228         /* Cancel subscription timer (if used), then delete subscription */
 229         if (sub->timeout != TIPC_WAIT_FOREVER) {
 230                 sub->timeout = TIPC_WAIT_FOREVER;
 231                 spin_unlock_bh(&subscriber->lock);
 232                 del_timer_sync(&sub->timer);
 233                 spin_lock_bh(&subscriber->lock);
 234         }
 235         subscr_del(sub);
 236 }
 237
 238 /**
 239  * subscr_subscribe - create subscription for subscriber
 240  *
 241  * Called with subscriber lock held.
 242  */
 243 static int subscr_subscribe(struct net *net, struct tipc_subscr *s,
 244                             struct tipc_subscriber *subscriber,
 245                             struct tipc_subscription **sub_p)
 246 {
 247         struct tipc_net *tn = net_generic(net, tipc_net_id);
 248         struct tipc_subscription *sub;
 249         int swap;
 250
 251         /* Determine subscriber's endianness */
 252         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 253
 254         /* Detect & process a subscription cancellation request */
 255         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 256                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 257                 subscr_cancel(s, subscriber);
 258                 return 0;
 259         }
 260
 261         /* Refuse subscription if global limit exceeded */
 262         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 263                 pr_warn("Subscription rejected, limit reached (%u)\n",
 264                         TIPC_MAX_SUBSCRIPTIONS);
 265                 return -EINVAL;
 266         }
 267
 268         /* Allocate subscription object */
 269         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 270         if (!sub) {
 271                 pr_warn("Subscription rejected, no memory\n");
 272                 return -ENOMEM;
 273         }
 274
 275         /* Initialize subscription object */
 276         sub->net = net;
 277         sub->seq.type = htohl(s->seq.type, swap);
 278         sub->seq.lower = htohl(s->seq.lower, swap);
 279         sub->seq.upper = htohl(s->seq.upper, swap);
 280         sub->timeout = msecs_to_jiffies(htohl(s->timeout, swap));
 281         sub->filter = htohl(s->filter, swap);
 282         if ((!(sub->filter & TIPC_SUB_PORTS) ==
 283              !(sub->filter & TIPC_SUB_SERVICE)) ||
 284             (sub->seq.lower > sub->seq.upper)) {
 285                 pr_warn("Subscription rejected, illegal request\n");
 286                 kfree(sub);
 287                 return -EINVAL;
 288         }
 289         list_add(&sub->subscription_list, &subscriber->subscription_list);
 290         sub->subscriber = subscriber;
 291         sub->swap = swap;
 292         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 293         atomic_inc(&tn->subscription_count);
 294         if (sub->timeout != TIPC_WAIT_FOREVER) {
 295                 setup_timer(&sub->timer, subscr_timeout, (unsigned long)sub);
 296                 mod_timer(&sub->timer, jiffies + sub->timeout);
 297         }
 298         *sub_p = sub;
 299         return 0;
 300 }
 301
 302 /* Handle one termination request for the subscriber */
 303 static void subscr_conn_shutdown_event(int conid, void *usr_data)
 304 {
 305         subscr_release((struct tipc_subscriber *)usr_data);
 306 }
 307
 308 /* Handle one request to create a new subscription for the subscriber */
 309 static void subscr_conn_msg_event(struct net *net, int conid,
 310                                   struct sockaddr_tipc *addr, void *usr_data,
 311                                   void *buf, size_t len)
 312 {
 313         struct tipc_subscriber *subscriber = usr_data;
 314         struct tipc_subscription *sub = NULL;
 315
 316         spin_lock_bh(&subscriber->lock);
 317         if (subscr_subscribe(net, (struct tipc_subscr *)buf, subscriber,
 318                              &sub) < 0) {
 319                 spin_unlock_bh(&subscriber->lock);
 320                 subscr_terminate(sub);
 321                 return;
 322         }
 323         if (sub)
 324                 tipc_nametbl_subscribe(sub);
 325         spin_unlock_bh(&subscriber->lock);
 326 }
 327
 328 /* Handle one request to establish a new subscriber */
 329 static void *subscr_named_msg_event(int conid)
 330 {
 331         struct tipc_subscriber *subscriber;
 332
 333         /* Create subscriber object */
 334         subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
 335         if (subscriber == NULL) {
 336                 pr_warn("Subscriber rejected, no memory\n");
 337                 return NULL;
 338         }
 339         INIT_LIST_HEAD(&subscriber->subscription_list);
 340         subscriber->conid = conid;
 341         spin_lock_init(&subscriber->lock);
 342
 343         return (void *)subscriber;
 344 }
 345
 346 int tipc_subscr_start(struct net *net)
 347 {
 348         struct tipc_net *tn = net_generic(net, tipc_net_id);
 349         const char name[] = "topology_server";
 350         struct tipc_server *topsrv;
 351         struct sockaddr_tipc *saddr;
 352
 353         saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
 354         if (!saddr)
 355                 return -ENOMEM;
 356         saddr->family                   = AF_TIPC;
 357         saddr->addrtype                 = TIPC_ADDR_NAMESEQ;
 358         saddr->addr.nameseq.type        = TIPC_TOP_SRV;
 359         saddr->addr.nameseq.lower       = TIPC_TOP_SRV;
 360         saddr->addr.nameseq.upper       = TIPC_TOP_SRV;
 361         saddr->scope                    = TIPC_NODE_SCOPE;
 362
 363         topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
 364         if (!topsrv) {
 365                 kfree(saddr);
 366                 return -ENOMEM;
 367         }
 368         topsrv->net                     = net;
 369         topsrv->saddr                   = saddr;
 370         topsrv->imp                     = TIPC_CRITICAL_IMPORTANCE;
 371         topsrv->type                    = SOCK_SEQPACKET;
 372         topsrv->max_rcvbuf_size         = sizeof(struct tipc_subscr);
 373         topsrv->tipc_conn_recvmsg       = subscr_conn_msg_event;
 374         topsrv->tipc_conn_new           = subscr_named_msg_event;
 375         topsrv->tipc_conn_shutdown      = subscr_conn_shutdown_event;
 376
 377         strncpy(topsrv->name, name, strlen(name) + 1);
 378         tn->topsrv = topsrv;
 379         atomic_set(&tn->subscription_count, 0);
 380
 381         return tipc_server_start(topsrv);
 382 }
 383
 384 void tipc_subscr_stop(struct net *net)
 385 {
 386         struct tipc_net *tn = net_generic(net, tipc_net_id);
 387         struct tipc_server *topsrv = tn->topsrv;
 388
 389         tipc_server_stop(topsrv);
 390         kfree(topsrv->saddr);
 391         kfree(topsrv);
 392 }