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: control 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
 100         msg_sect.iov_base = (void *)&sub->evt;
 101         msg_sect.iov_len = sizeof(struct tipc_event);
 102         sub->evt.event = htohl(event, sub->swap);
 103         sub->evt.found_lower = htohl(found_lower, sub->swap);
 104         sub->evt.found_upper = htohl(found_upper, sub->swap);
 105         sub->evt.port.ref = htohl(port_ref, sub->swap);
 106         sub->evt.port.node = htohl(node, sub->swap);
 107         tipc_conn_sendmsg(&topsrv, subscriber->conid, NULL, msg_sect.iov_base,
 108                           msg_sect.iov_len);
 109 }
 110
 111 /**
 112  * tipc_subscr_overlap - test for subscription overlap with the given values
 113  *
 114  * Returns 1 if there is overlap, otherwise 0.
 115  */
 116 int tipc_subscr_overlap(struct tipc_subscription *sub, u32 found_lower,
 117                         u32 found_upper)
 118 {
 119         if (found_lower < sub->seq.lower)
 120                 found_lower = sub->seq.lower;
 121         if (found_upper > sub->seq.upper)
 122                 found_upper = sub->seq.upper;
 123         if (found_lower > found_upper)
 124                 return 0;
 125         return 1;
 126 }
 127
 128 /**
 129  * tipc_subscr_report_overlap - issue event if there is subscription overlap
 130  *
 131  * Protected by nameseq.lock in name_table.c
 132  */
 133 void tipc_subscr_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 134                                 u32 found_upper, u32 event, u32 port_ref,
 135                                 u32 node, int must)
 136 {
 137         if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 138                 return;
 139         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 140                 return;
 141
 142         subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
 143 }
 144
 145 static void subscr_timeout(struct tipc_subscription *sub)
 146 {
 147         struct tipc_subscriber *subscriber = sub->subscriber;
 148
 149         /* The spin lock per subscriber is used to protect its members */
 150         spin_lock_bh(&subscriber->lock);
 151
 152         /* Validate timeout (in case subscription is being cancelled) */
 153         if (sub->timeout == TIPC_WAIT_FOREVER) {
 154                 spin_unlock_bh(&subscriber->lock);
 155                 return;
 156         }
 157
 158         /* Unlink subscription from name table */
 159         tipc_nametbl_unsubscribe(sub);
 160
 161         /* Unlink subscription from subscriber */
 162         list_del(&sub->subscription_list);
 163
 164         spin_unlock_bh(&subscriber->lock);
 165
 166         /* Notify subscriber of timeout */
 167         subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 168                           TIPC_SUBSCR_TIMEOUT, 0, 0);
 169
 170         /* Now destroy subscription */
 171         k_term_timer(&sub->timer);
 172         kfree(sub);
 173         atomic_dec(&subscription_count);
 174 }
 175
 176 /**
 177  * subscr_del - delete a subscription within a subscription list
 178  *
 179  * Called with subscriber lock held.
 180  */
 181 static void subscr_del(struct tipc_subscription *sub)
 182 {
 183         tipc_nametbl_unsubscribe(sub);
 184         list_del(&sub->subscription_list);
 185         kfree(sub);
 186         atomic_dec(&subscription_count);
 187 }
 188
 189 /**
 190  * subscr_terminate - terminate communication with a subscriber
 191  *
 192  * Note: Must call it in process context since it might sleep.
 193  */
 194 static void subscr_terminate(struct tipc_subscriber *subscriber)
 195 {
 196         tipc_conn_terminate(&topsrv, subscriber->conid);
 197 }
 198
 199 static void subscr_release(struct tipc_subscriber *subscriber)
 200 {
 201         struct tipc_subscription *sub;
 202         struct tipc_subscription *sub_temp;
 203
 204         spin_lock_bh(&subscriber->lock);
 205
 206         /* Destroy any existing subscriptions for subscriber */
 207         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 208                                  subscription_list) {
 209                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 210                         spin_unlock_bh(&subscriber->lock);
 211                         k_cancel_timer(&sub->timer);
 212                         k_term_timer(&sub->timer);
 213                         spin_lock_bh(&subscriber->lock);
 214                 }
 215                 subscr_del(sub);
 216         }
 217         spin_unlock_bh(&subscriber->lock);
 218
 219         /* Now destroy subscriber */
 220         kfree(subscriber);
 221 }
 222
 223 /**
 224  * subscr_cancel - handle subscription cancellation request
 225  *
 226  * Called with subscriber lock held. Routine must temporarily release lock
 227  * to enable the subscription timeout routine to finish without deadlocking;
 228  * the lock is then reclaimed to allow caller to release it upon return.
 229  *
 230  * Note that fields of 's' use subscriber's endianness!
 231  */
 232 static void subscr_cancel(struct tipc_subscr *s,
 233                           struct tipc_subscriber *subscriber)
 234 {
 235         struct tipc_subscription *sub;
 236         struct tipc_subscription *sub_temp;
 237         int found = 0;
 238
 239         /* Find first matching subscription, exit if not found */
 240         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 241                                  subscription_list) {
 242                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 243                         found = 1;
 244                         break;
 245                 }
 246         }
 247         if (!found)
 248                 return;
 249
 250         /* Cancel subscription timer (if used), then delete subscription */
 251         if (sub->timeout != TIPC_WAIT_FOREVER) {
 252                 sub->timeout = TIPC_WAIT_FOREVER;
 253                 spin_unlock_bh(&subscriber->lock);
 254                 k_cancel_timer(&sub->timer);
 255                 k_term_timer(&sub->timer);
 256                 spin_lock_bh(&subscriber->lock);
 257         }
 258         subscr_del(sub);
 259 }
 260
 261 /**
 262  * subscr_subscribe - create subscription for subscriber
 263  *
 264  * Called with subscriber lock held.
 265  */
 266 static int subscr_subscribe(struct tipc_subscr *s,
 267                             struct tipc_subscriber *subscriber,
 268                             struct tipc_subscription **sub_p) {
 269         struct tipc_subscription *sub;
 270         int swap;
 271
 272         /* Determine subscriber's endianness */
 273         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 274
 275         /* Detect & process a subscription cancellation request */
 276         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 277                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 278                 subscr_cancel(s, subscriber);
 279                 return 0;
 280         }
 281
 282         /* Refuse subscription if global limit exceeded */
 283         if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 284                 pr_warn("Subscription rejected, limit reached (%u)\n",
 285                         TIPC_MAX_SUBSCRIPTIONS);
 286                 return -EINVAL;
 287         }
 288
 289         /* Allocate subscription object */
 290         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 291         if (!sub) {
 292                 pr_warn("Subscription rejected, no memory\n");
 293                 return -ENOMEM;
 294         }
 295
 296         /* Initialize subscription object */
 297         sub->seq.type = htohl(s->seq.type, swap);
 298         sub->seq.lower = htohl(s->seq.lower, swap);
 299         sub->seq.upper = htohl(s->seq.upper, swap);
 300         sub->timeout = htohl(s->timeout, swap);
 301         sub->filter = htohl(s->filter, swap);
 302         if ((!(sub->filter & TIPC_SUB_PORTS) ==
 303              !(sub->filter & TIPC_SUB_SERVICE)) ||
 304             (sub->seq.lower > sub->seq.upper)) {
 305                 pr_warn("Subscription rejected, illegal request\n");
 306                 kfree(sub);
 307                 return -EINVAL;
 308         }
 309         INIT_LIST_HEAD(&sub->nameseq_list);
 310         list_add(&sub->subscription_list, &subscriber->subscription_list);
 311         sub->subscriber = subscriber;
 312         sub->swap = swap;
 313         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 314         atomic_inc(&subscription_count);
 315         if (sub->timeout != TIPC_WAIT_FOREVER) {
 316                 k_init_timer(&sub->timer,
 317                              (Handler)subscr_timeout, (unsigned long)sub);
 318                 k_start_timer(&sub->timer, sub->timeout);
 319         }
 320         *sub_p = sub;
 321         return 0;
 322 }
 323
 324 /* Handle one termination request for the subscriber */
 325 static void subscr_conn_shutdown_event(int conid, void *usr_data)
 326 {
 327         subscr_release((struct tipc_subscriber *)usr_data);
 328 }
 329
 330 /* Handle one request to create a new subscription for the subscriber */
 331 static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
 332                                   void *usr_data, void *buf, size_t len)
 333 {
 334         struct tipc_subscriber *subscriber = usr_data;
 335         struct tipc_subscription *sub = NULL;
 336
 337         spin_lock_bh(&subscriber->lock);
 338         if (subscr_subscribe((struct tipc_subscr *)buf, subscriber, &sub) < 0) {
 339                 spin_unlock_bh(&subscriber->lock);
 340                 subscr_terminate(subscriber);
 341                 return;
 342         }
 343         if (sub)
 344                 tipc_nametbl_subscribe(sub);
 345         spin_unlock_bh(&subscriber->lock);
 346 }
 347
 348
 349 /* Handle one request to establish a new subscriber */
 350 static void *subscr_named_msg_event(int conid)
 351 {
 352         struct tipc_subscriber *subscriber;
 353
 354         /* Create subscriber object */
 355         subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
 356         if (subscriber == NULL) {
 357                 pr_warn("Subscriber rejected, no memory\n");
 358                 return NULL;
 359         }
 360         INIT_LIST_HEAD(&subscriber->subscription_list);
 361         subscriber->conid = conid;
 362         spin_lock_init(&subscriber->lock);
 363
 364         return (void *)subscriber;
 365 }
 366
 367 int tipc_subscr_start(void)
 368 {
 369         return tipc_server_start(&topsrv);
 370 }
 371
 372 void tipc_subscr_stop(void)
 373 {
 374         tipc_server_stop(&topsrv);
 375 }