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, int must)
 122 {
 123         struct tipc_name_seq seq;
 124
 125         tipc_subscrp_convert_seq(&sub->evt.s.seq, sub->swap, &seq);
 126         if (!tipc_subscrp_check_overlap(&seq, found_lower, found_upper))
 127                 return;
 128         if (!must &&
 129             !(htohl(sub->evt.s.filter, sub->swap) & TIPC_SUB_PORTS))
 130                 return;
 131
 132         tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
 133                                 node);
 134 }
 135
 136 static void tipc_subscrp_timeout(unsigned long data)
 137 {
 138         struct tipc_subscription *sub = (struct tipc_subscription *)data;
 139         struct tipc_subscriber *subscriber = sub->subscriber;
 140
 141         spin_lock_bh(&subscriber->lock);
 142         tipc_nametbl_unsubscribe(sub);
 143         list_del(&sub->subscrp_list);
 144         spin_unlock_bh(&subscriber->lock);
 145
 146         /* Notify subscriber of timeout */
 147         tipc_subscrp_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 148                                 TIPC_SUBSCR_TIMEOUT, 0, 0);
 149
 150         tipc_subscrp_put(sub);
 151 }
 152
 153 static void tipc_subscrb_kref_release(struct kref *kref)
 154 {
 155         kfree(container_of(kref,struct tipc_subscriber, kref));
 156 }
 157
 158 static void tipc_subscrb_put(struct tipc_subscriber *subscriber)
 159 {
 160         kref_put(&subscriber->kref, tipc_subscrb_kref_release);
 161 }
 162
 163 static void tipc_subscrb_get(struct tipc_subscriber *subscriber)
 164 {
 165         kref_get(&subscriber->kref);
 166 }
 167
 168 static void tipc_subscrp_kref_release(struct kref *kref)
 169 {
 170         struct tipc_subscription *sub = container_of(kref,
 171                                                      struct tipc_subscription,
 172                                                      kref);
 173         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 174         struct tipc_subscriber *subscriber = sub->subscriber;
 175
 176         atomic_dec(&tn->subscription_count);
 177         kfree(sub);
 178         tipc_subscrb_put(subscriber);
 179 }
 180
 181 void tipc_subscrp_put(struct tipc_subscription *subscription)
 182 {
 183         kref_put(&subscription->kref, tipc_subscrp_kref_release);
 184 }
 185
 186 void tipc_subscrp_get(struct tipc_subscription *subscription)
 187 {
 188         kref_get(&subscription->kref);
 189 }
 190
 191 /* tipc_subscrb_subscrp_delete - delete a specific subscription or all
 192  * subscriptions for a given subscriber.
 193  */
 194 static void tipc_subscrb_subscrp_delete(struct tipc_subscriber *subscriber,
 195                                         struct tipc_subscr *s)
 196 {
 197         struct list_head *subscription_list = &subscriber->subscrp_list;
 198         struct tipc_subscription *sub, *temp;
 199         u32 timeout;
 200
 201         spin_lock_bh(&subscriber->lock);
 202         list_for_each_entry_safe(sub, temp, subscription_list,  subscrp_list) {
 203                 if (s && memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr)))
 204                         continue;
 205
 206                 timeout = htohl(sub->evt.s.timeout, sub->swap);
 207                 if (timeout == TIPC_WAIT_FOREVER || del_timer(&sub->timer)) {
 208                         tipc_nametbl_unsubscribe(sub);
 209                         list_del(&sub->subscrp_list);
 210                         tipc_subscrp_put(sub);
 211                 }
 212
 213                 if (s)
 214                         break;
 215         }
 216         spin_unlock_bh(&subscriber->lock);
 217 }
 218
 219 static struct tipc_subscriber *tipc_subscrb_create(int conid)
 220 {
 221         struct tipc_subscriber *subscriber;
 222
 223         subscriber = kzalloc(sizeof(*subscriber), GFP_ATOMIC);
 224         if (!subscriber) {
 225                 pr_warn("Subscriber rejected, no memory\n");
 226                 return NULL;
 227         }
 228         INIT_LIST_HEAD(&subscriber->subscrp_list);
 229         kref_init(&subscriber->kref);
 230         subscriber->conid = conid;
 231         spin_lock_init(&subscriber->lock);
 232
 233         return subscriber;
 234 }
 235
 236 static void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
 237 {
 238         tipc_subscrb_subscrp_delete(subscriber, NULL);
 239         tipc_subscrb_put(subscriber);
 240 }
 241
 242 static void tipc_subscrp_cancel(struct tipc_subscr *s,
 243                                 struct tipc_subscriber *subscriber)
 244 {
 245         tipc_subscrb_get(subscriber);
 246         tipc_subscrb_subscrp_delete(subscriber, s);
 247         tipc_subscrb_put(subscriber);
 248 }
 249
 250 static struct tipc_subscription *tipc_subscrp_create(struct net *net,
 251                                                      struct tipc_subscr *s,
 252                                                      int swap)
 253 {
 254         struct tipc_net *tn = net_generic(net, tipc_net_id);
 255         struct tipc_subscription *sub;
 256         u32 filter = htohl(s->filter, swap);
 257
 258         /* Refuse subscription if global limit exceeded */
 259         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 260                 pr_warn("Subscription rejected, limit reached (%u)\n",
 261                         TIPC_MAX_SUBSCRIPTIONS);
 262                 return NULL;
 263         }
 264
 265         /* Allocate subscription object */
 266         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 267         if (!sub) {
 268                 pr_warn("Subscription rejected, no memory\n");
 269                 return NULL;
 270         }
 271
 272         /* Initialize subscription object */
 273         sub->net = net;
 274         if (((filter & TIPC_SUB_PORTS) && (filter & TIPC_SUB_SERVICE)) ||
 275             (htohl(s->seq.lower, swap) > htohl(s->seq.upper, swap))) {
 276                 pr_warn("Subscription rejected, illegal request\n");
 277                 kfree(sub);
 278                 return NULL;
 279         }
 280
 281         sub->swap = swap;
 282         memcpy(&sub->evt.s, s, sizeof(*s));
 283         atomic_inc(&tn->subscription_count);
 284         kref_init(&sub->kref);
 285         return sub;
 286 }
 287
 288 static void tipc_subscrp_subscribe(struct net *net, struct tipc_subscr *s,
 289                                    struct tipc_subscriber *subscriber, int swap)
 290 {
 291         struct tipc_net *tn = net_generic(net, tipc_net_id);
 292         struct tipc_subscription *sub = NULL;
 293         u32 timeout;
 294
 295         sub = tipc_subscrp_create(net, s, swap);
 296         if (!sub)
 297                 return tipc_conn_terminate(tn->topsrv, subscriber->conid);
 298
 299         spin_lock_bh(&subscriber->lock);
 300         list_add(&sub->subscrp_list, &subscriber->subscrp_list);
 301         sub->subscriber = subscriber;
 302         tipc_nametbl_subscribe(sub);
 303         tipc_subscrb_get(subscriber);
 304         spin_unlock_bh(&subscriber->lock);
 305
 306         setup_timer(&sub->timer, tipc_subscrp_timeout, (unsigned long)sub);
 307         timeout = htohl(sub->evt.s.timeout, swap);
 308
 309         if (timeout != TIPC_WAIT_FOREVER)
 310                 mod_timer(&sub->timer, jiffies + msecs_to_jiffies(timeout));
 311 }
 312
 313 /* Handle one termination request for the subscriber */
 314 static void tipc_subscrb_release_cb(int conid, void *usr_data)
 315 {
 316         tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
 317 }
 318
 319 /* Handle one request to create a new subscription for the subscriber */
 320 static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 321                                 struct sockaddr_tipc *addr, void *usr_data,
 322                                 void *buf, size_t len)
 323 {
 324         struct tipc_subscriber *subscriber = usr_data;
 325         struct tipc_subscr *s = (struct tipc_subscr *)buf;
 326         int swap;
 327
 328         /* Determine subscriber's endianness */
 329         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE |
 330                               TIPC_SUB_CANCEL));
 331
 332         /* Detect & process a subscription cancellation request */
 333         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 334                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 335                 return tipc_subscrp_cancel(s, subscriber);
 336         }
 337
 338         tipc_subscrp_subscribe(net, s, subscriber, swap);
 339 }
 340
 341 /* Handle one request to establish a new subscriber */
 342 static void *tipc_subscrb_connect_cb(int conid)
 343 {
 344         return (void *)tipc_subscrb_create(conid);
 345 }
 346
 347 int tipc_topsrv_start(struct net *net)
 348 {
 349         struct tipc_net *tn = net_generic(net, tipc_net_id);
 350         const char name[] = "topology_server";
 351         struct tipc_server *topsrv;
 352         struct sockaddr_tipc *saddr;
 353
 354         saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
 355         if (!saddr)
 356                 return -ENOMEM;
 357         saddr->family                   = AF_TIPC;
 358         saddr->addrtype                 = TIPC_ADDR_NAMESEQ;
 359         saddr->addr.nameseq.type        = TIPC_TOP_SRV;
 360         saddr->addr.nameseq.lower       = TIPC_TOP_SRV;
 361         saddr->addr.nameseq.upper       = TIPC_TOP_SRV;
 362         saddr->scope                    = TIPC_NODE_SCOPE;
 363
 364         topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
 365         if (!topsrv) {
 366                 kfree(saddr);
 367                 return -ENOMEM;
 368         }
 369         topsrv->net                     = net;
 370         topsrv->saddr                   = saddr;
 371         topsrv->imp                     = TIPC_CRITICAL_IMPORTANCE;
 372         topsrv->type                    = SOCK_SEQPACKET;
 373         topsrv->max_rcvbuf_size         = sizeof(struct tipc_subscr);
 374         topsrv->tipc_conn_recvmsg       = tipc_subscrb_rcv_cb;
 375         topsrv->tipc_conn_new           = tipc_subscrb_connect_cb;
 376         topsrv->tipc_conn_release       = tipc_subscrb_release_cb;
 377
 378         strncpy(topsrv->name, name, strlen(name) + 1);
 379         tn->topsrv = topsrv;
 380         atomic_set(&tn->subscription_count, 0);
 381
 382         return tipc_server_start(topsrv);
 383 }
 384
 385 void tipc_topsrv_stop(struct net *net)
 386 {
 387         struct tipc_net *tn = net_generic(net, tipc_net_id);
 388         struct tipc_server *topsrv = tn->topsrv;
 389
 390         tipc_server_stop(topsrv);
 391         kfree(topsrv->saddr);
 392         kfree(topsrv);
 393 }