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