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  * @kref: reference counter to tipc_subscription object
  44  * @conid: connection identifier to server connecting to subscriber
  45  * @lock: control access to subscriber
  46  * @subscrp_list: list of subscription objects for this subscriber
  47  */
  48 struct tipc_subscriber {
  49         struct kref kref;
  50         int conid;
  51         spinlock_t lock;
  52         struct list_head subscrp_list;
  53 };
  54
  55 static void tipc_subscrp_delete(struct tipc_subscription *sub);
  56 static void tipc_subscrb_put(struct tipc_subscriber *subscriber);
  57 static void tipc_subscrp_put(struct tipc_subscription *subscription);
  58 static void tipc_subscrp_get(struct tipc_subscription *subscription);
  59
  60 /**
  61  * htohl - convert value to endianness used by destination
  62  * @in: value to convert
  63  * @swap: non-zero if endianness must be reversed
  64  *
  65  * Returns converted value
  66  */
  67 static u32 htohl(u32 in, int swap)
  68 {
  69         return swap ? swab32(in) : in;
  70 }
  71
  72 static void tipc_subscrp_send_event(struct tipc_subscription *sub,
  73                                     u32 found_lower, u32 found_upper,
  74                                     u32 event, u32 port_ref, u32 node)
  75 {
  76         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
  77         struct tipc_subscriber *subscriber = sub->subscriber;
  78         struct kvec msg_sect;
  79
  80         msg_sect.iov_base = (void *)&sub->evt;
  81         msg_sect.iov_len = sizeof(struct tipc_event);
  82         sub->evt.event = htohl(event, sub->swap);
  83         sub->evt.found_lower = htohl(found_lower, sub->swap);
  84         sub->evt.found_upper = htohl(found_upper, sub->swap);
  85         sub->evt.port.ref = htohl(port_ref, sub->swap);
  86         sub->evt.port.node = htohl(node, sub->swap);
  87         tipc_conn_sendmsg(tn->topsrv, subscriber->conid, NULL,
  88                           msg_sect.iov_base, msg_sect.iov_len);
  89 }
  90
  91 /**
  92  * tipc_subscrp_check_overlap - test for subscription overlap with the
  93  * given values
  94  *
  95  * Returns 1 if there is overlap, otherwise 0.
  96  */
  97 int tipc_subscrp_check_overlap(struct tipc_name_seq *seq, u32 found_lower,
  98                                u32 found_upper)
  99 {
 100         if (found_lower < seq->lower)
 101                 found_lower = seq->lower;
 102         if (found_upper > seq->upper)
 103                 found_upper = seq->upper;
 104         if (found_lower > found_upper)
 105                 return 0;
 106         return 1;
 107 }
 108
 109 u32 tipc_subscrp_convert_seq_type(u32 type, int swap)
 110 {
 111         return htohl(type, swap);
 112 }
 113
 114 void tipc_subscrp_convert_seq(struct tipc_name_seq *in, int swap,
 115                               struct tipc_name_seq *out)
 116 {
 117         out->type = htohl(in->type, swap);
 118         out->lower = htohl(in->lower, swap);
 119         out->upper = htohl(in->upper, swap);
 120 }
 121
 122 void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 123                                  u32 found_upper, u32 event, u32 port_ref,
 124                                  u32 node, int must)
 125 {
 126         struct tipc_name_seq seq;
 127
 128         tipc_subscrp_get(sub);
 129         tipc_subscrp_convert_seq(&sub->evt.s.seq, sub->swap, &seq);
 130         if (!tipc_subscrp_check_overlap(&seq, found_lower, found_upper))
 131                 return;
 132         if (!must &&
 133             !(htohl(sub->evt.s.filter, sub->swap) & TIPC_SUB_PORTS))
 134                 return;
 135
 136         tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
 137                                 node);
 138         tipc_subscrp_put(sub);
 139 }
 140
 141 static void tipc_subscrp_timeout(unsigned long data)
 142 {
 143         struct tipc_subscription *sub = (struct tipc_subscription *)data;
 144         struct tipc_subscriber *subscriber = sub->subscriber;
 145
 146         spin_lock_bh(&subscriber->lock);
 147         tipc_nametbl_unsubscribe(sub);
 148         spin_unlock_bh(&subscriber->lock);
 149
 150         /* Notify subscriber of timeout */
 151         tipc_subscrp_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 152                                 TIPC_SUBSCR_TIMEOUT, 0, 0);
 153
 154         tipc_subscrp_put(sub);
 155 }
 156
 157 static void tipc_subscrb_kref_release(struct kref *kref)
 158 {
 159         kfree(container_of(kref,struct tipc_subscriber, kref));
 160 }
 161
 162 static void tipc_subscrb_put(struct tipc_subscriber *subscriber)
 163 {
 164         kref_put(&subscriber->kref, tipc_subscrb_kref_release);
 165 }
 166
 167 static void tipc_subscrb_get(struct tipc_subscriber *subscriber)
 168 {
 169         kref_get(&subscriber->kref);
 170 }
 171
 172 static void tipc_subscrp_kref_release(struct kref *kref)
 173 {
 174         struct tipc_subscription *sub = container_of(kref,
 175                                                      struct tipc_subscription,
 176                                                      kref);
 177         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 178         struct tipc_subscriber *subscriber = sub->subscriber;
 179
 180         spin_lock_bh(&subscriber->lock);
 181         list_del(&sub->subscrp_list);
 182         atomic_dec(&tn->subscription_count);
 183         spin_unlock_bh(&subscriber->lock);
 184         kfree(sub);
 185         tipc_subscrb_put(subscriber);
 186 }
 187
 188 static void tipc_subscrp_put(struct tipc_subscription *subscription)
 189 {
 190         kref_put(&subscription->kref, tipc_subscrp_kref_release);
 191 }
 192
 193 static void tipc_subscrp_get(struct tipc_subscription *subscription)
 194 {
 195         kref_get(&subscription->kref);
 196 }
 197
 198 /* tipc_subscrb_subscrp_delete - delete a specific subscription or all
 199  * subscriptions for a given subscriber.
 200  */
 201 static void tipc_subscrb_subscrp_delete(struct tipc_subscriber *subscriber,
 202                                         struct tipc_subscr *s)
 203 {
 204         struct list_head *subscription_list = &subscriber->subscrp_list;
 205         struct tipc_subscription *sub, *temp;
 206
 207         spin_lock_bh(&subscriber->lock);
 208         list_for_each_entry_safe(sub, temp, subscription_list,  subscrp_list) {
 209                 if (s && memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr)))
 210                         continue;
 211
 212                 tipc_nametbl_unsubscribe(sub);
 213                 tipc_subscrp_get(sub);
 214                 spin_unlock_bh(&subscriber->lock);
 215                 tipc_subscrp_delete(sub);
 216                 tipc_subscrp_put(sub);
 217                 spin_lock_bh(&subscriber->lock);
 218
 219                 if (s)
 220                         break;
 221         }
 222         spin_unlock_bh(&subscriber->lock);
 223 }
 224
 225 static struct tipc_subscriber *tipc_subscrb_create(int conid)
 226 {
 227         struct tipc_subscriber *subscriber;
 228
 229         subscriber = kzalloc(sizeof(*subscriber), GFP_ATOMIC);
 230         if (!subscriber) {
 231                 pr_warn("Subscriber rejected, no memory\n");
 232                 return NULL;
 233         }
 234         INIT_LIST_HEAD(&subscriber->subscrp_list);
 235         kref_init(&subscriber->kref);
 236         subscriber->conid = conid;
 237         spin_lock_init(&subscriber->lock);
 238
 239         return subscriber;
 240 }
 241
 242 static void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
 243 {
 244         tipc_subscrb_subscrp_delete(subscriber, NULL);
 245         tipc_subscrb_put(subscriber);
 246 }
 247
 248 static void tipc_subscrp_delete(struct tipc_subscription *sub)
 249 {
 250         u32 timeout = htohl(sub->evt.s.timeout, sub->swap);
 251
 252         if (timeout == TIPC_WAIT_FOREVER || del_timer(&sub->timer))
 253                 tipc_subscrp_put(sub);
 254 }
 255
 256 static void tipc_subscrp_cancel(struct tipc_subscr *s,
 257                                 struct tipc_subscriber *subscriber)
 258 {
 259         tipc_subscrb_subscrp_delete(subscriber, s);
 260 }
 261
 262 static struct tipc_subscription *tipc_subscrp_create(struct net *net,
 263                                                      struct tipc_subscr *s,
 264                                                      int swap)
 265 {
 266         struct tipc_net *tn = net_generic(net, tipc_net_id);
 267         struct tipc_subscription *sub;
 268         u32 filter = htohl(s->filter, swap);
 269
 270         /* Refuse subscription if global limit exceeded */
 271         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 272                 pr_warn("Subscription rejected, limit reached (%u)\n",
 273                         TIPC_MAX_SUBSCRIPTIONS);
 274                 return NULL;
 275         }
 276
 277         /* Allocate subscription object */
 278         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 279         if (!sub) {
 280                 pr_warn("Subscription rejected, no memory\n");
 281                 return NULL;
 282         }
 283
 284         /* Initialize subscription object */
 285         sub->net = net;
 286         if (((filter & TIPC_SUB_PORTS) && (filter & TIPC_SUB_SERVICE)) ||
 287             (htohl(s->seq.lower, swap) > htohl(s->seq.upper, swap))) {
 288                 pr_warn("Subscription rejected, illegal request\n");
 289                 kfree(sub);
 290                 return NULL;
 291         }
 292
 293         sub->swap = swap;
 294         memcpy(&sub->evt.s, s, sizeof(*s));
 295         atomic_inc(&tn->subscription_count);
 296         kref_init(&sub->kref);
 297         return sub;
 298 }
 299
 300 static void tipc_subscrp_subscribe(struct net *net, struct tipc_subscr *s,
 301                                    struct tipc_subscriber *subscriber, int swap)
 302 {
 303         struct tipc_net *tn = net_generic(net, tipc_net_id);
 304         struct tipc_subscription *sub = NULL;
 305         u32 timeout;
 306
 307         sub = tipc_subscrp_create(net, s, swap);
 308         if (!sub)
 309                 return tipc_conn_terminate(tn->topsrv, subscriber->conid);
 310
 311         spin_lock_bh(&subscriber->lock);
 312         list_add(&sub->subscrp_list, &subscriber->subscrp_list);
 313         sub->subscriber = subscriber;
 314         tipc_nametbl_subscribe(sub);
 315         tipc_subscrb_get(subscriber);
 316         spin_unlock_bh(&subscriber->lock);
 317
 318         setup_timer(&sub->timer, tipc_subscrp_timeout, (unsigned long)sub);
 319         timeout = htohl(sub->evt.s.timeout, swap);
 320
 321         if (timeout != TIPC_WAIT_FOREVER)
 322                 mod_timer(&sub->timer, jiffies + msecs_to_jiffies(timeout));
 323 }
 324
 325 /* Handle one termination request for the subscriber */
 326 static void tipc_subscrb_release_cb(int conid, void *usr_data)
 327 {
 328         tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
 329 }
 330
 331 /* Handle one request to create a new subscription for the subscriber */
 332 static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 333                                 struct sockaddr_tipc *addr, void *usr_data,
 334                                 void *buf, size_t len)
 335 {
 336         struct tipc_subscriber *subscriber = usr_data;
 337         struct tipc_subscr *s = (struct tipc_subscr *)buf;
 338         int swap;
 339
 340         /* Determine subscriber's endianness */
 341         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE |
 342                               TIPC_SUB_CANCEL));
 343
 344         /* Detect & process a subscription cancellation request */
 345         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 346                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 347                 return tipc_subscrp_cancel(s, subscriber);
 348         }
 349
 350         tipc_subscrp_subscribe(net, s, subscriber, swap);
 351 }
 352
 353 /* Handle one request to establish a new subscriber */
 354 static void *tipc_subscrb_connect_cb(int conid)
 355 {
 356         return (void *)tipc_subscrb_create(conid);
 357 }
 358
 359 int tipc_topsrv_start(struct net *net)
 360 {
 361         struct tipc_net *tn = net_generic(net, tipc_net_id);
 362         const char name[] = "topology_server";
 363         struct tipc_server *topsrv;
 364         struct sockaddr_tipc *saddr;
 365
 366         saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
 367         if (!saddr)
 368                 return -ENOMEM;
 369         saddr->family                   = AF_TIPC;
 370         saddr->addrtype                 = TIPC_ADDR_NAMESEQ;
 371         saddr->addr.nameseq.type        = TIPC_TOP_SRV;
 372         saddr->addr.nameseq.lower       = TIPC_TOP_SRV;
 373         saddr->addr.nameseq.upper       = TIPC_TOP_SRV;
 374         saddr->scope                    = TIPC_NODE_SCOPE;
 375
 376         topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
 377         if (!topsrv) {
 378                 kfree(saddr);
 379                 return -ENOMEM;
 380         }
 381         topsrv->net                     = net;
 382         topsrv->saddr                   = saddr;
 383         topsrv->imp                     = TIPC_CRITICAL_IMPORTANCE;
 384         topsrv->type                    = SOCK_SEQPACKET;
 385         topsrv->max_rcvbuf_size         = sizeof(struct tipc_subscr);
 386         topsrv->tipc_conn_recvmsg       = tipc_subscrb_rcv_cb;
 387         topsrv->tipc_conn_new           = tipc_subscrb_connect_cb;
 388         topsrv->tipc_conn_release       = tipc_subscrb_release_cb;
 389
 390         strncpy(topsrv->name, name, strlen(name) + 1);
 391         tn->topsrv = topsrv;
 392         atomic_set(&tn->subscription_count, 0);
 393
 394         return tipc_server_start(topsrv);
 395 }
 396
 397 void tipc_topsrv_stop(struct net *net)
 398 {
 399         struct tipc_net *tn = net_generic(net, tipc_net_id);
 400         struct tipc_server *topsrv = tn->topsrv;
 401
 402         tipc_server_stop(topsrv);
 403         kfree(topsrv->saddr);
 404         kfree(topsrv);
 405 }