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  * @subscrp_list: list of subscription objects for this subscriber
  46  */
  47 struct tipc_subscriber {
  48         int conid;
  49         spinlock_t lock;
  50         struct list_head subscrp_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 tipc_subscrp_send_event(struct tipc_subscription *sub,
  66                                     u32 found_lower, u32 found_upper,
  67                                     u32 event, u32 port_ref, 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_subscrp_check_overlap - test for subscription overlap with the
  86  * given values
  87  *
  88  * Returns 1 if there is overlap, otherwise 0.
  89  */
  90 int tipc_subscrp_check_overlap(struct tipc_subscription *sub, u32 found_lower,
  91                                u32 found_upper)
  92 {
  93         if (found_lower < sub->seq.lower)
  94                 found_lower = sub->seq.lower;
  95         if (found_upper > sub->seq.upper)
  96                 found_upper = sub->seq.upper;
  97         if (found_lower > found_upper)
  98                 return 0;
  99         return 1;
 100 }
 101
 102 void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 103                                  u32 found_upper, u32 event, u32 port_ref,
 104                                  u32 node, int must)
 105 {
 106         if (!tipc_subscrp_check_overlap(sub, found_lower, found_upper))
 107                 return;
 108         if (!must && !(sub->filter & TIPC_SUB_PORTS))
 109                 return;
 110
 111         tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
 112                                 node);
 113 }
 114
 115 static void tipc_subscrp_timeout(unsigned long data)
 116 {
 117         struct tipc_subscription *sub = (struct tipc_subscription *)data;
 118         struct tipc_subscriber *subscriber = sub->subscriber;
 119         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 120
 121         /* The spin lock per subscriber is used to protect its members */
 122         spin_lock_bh(&subscriber->lock);
 123
 124         /* Validate timeout (in case subscription is being cancelled) */
 125         if (sub->timeout == TIPC_WAIT_FOREVER) {
 126                 spin_unlock_bh(&subscriber->lock);
 127                 return;
 128         }
 129
 130         /* Unlink subscription from name table */
 131         tipc_nametbl_unsubscribe(sub);
 132
 133         /* Unlink subscription from subscriber */
 134         list_del(&sub->subscrp_list);
 135
 136         spin_unlock_bh(&subscriber->lock);
 137
 138         /* Notify subscriber of timeout */
 139         tipc_subscrp_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 140                                 TIPC_SUBSCR_TIMEOUT, 0, 0);
 141
 142         /* Now destroy subscription */
 143         kfree(sub);
 144         atomic_dec(&tn->subscription_count);
 145 }
 146
 147 static void tipc_subscrp_delete(struct tipc_subscription *sub)
 148 {
 149         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 150
 151         tipc_nametbl_unsubscribe(sub);
 152         list_del(&sub->subscrp_list);
 153         kfree(sub);
 154         atomic_dec(&tn->subscription_count);
 155 }
 156
 157 static struct tipc_subscriber *tipc_subscrb_create(int conid)
 158 {
 159         struct tipc_subscriber *subscriber;
 160
 161         subscriber = kzalloc(sizeof(*subscriber), GFP_ATOMIC);
 162         if (!subscriber) {
 163                 pr_warn("Subscriber rejected, no memory\n");
 164                 return NULL;
 165         }
 166         INIT_LIST_HEAD(&subscriber->subscrp_list);
 167         subscriber->conid = conid;
 168         spin_lock_init(&subscriber->lock);
 169
 170         return subscriber;
 171 }
 172
 173 static void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
 174 {
 175         struct tipc_subscription *sub;
 176         struct tipc_subscription *sub_temp;
 177
 178         spin_lock_bh(&subscriber->lock);
 179
 180         /* Destroy any existing subscriptions for subscriber */
 181         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscrp_list,
 182                                  subscrp_list) {
 183                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 184                         spin_unlock_bh(&subscriber->lock);
 185                         del_timer_sync(&sub->timer);
 186                         spin_lock_bh(&subscriber->lock);
 187                 }
 188                 tipc_subscrp_delete(sub);
 189         }
 190         spin_unlock_bh(&subscriber->lock);
 191
 192         /* Now destroy subscriber */
 193         kfree(subscriber);
 194 }
 195
 196 /**
 197  * tipc_subscrp_cancel - handle subscription cancellation request
 198  *
 199  * Called with subscriber lock held. Routine must temporarily release lock
 200  * to enable the subscription timeout routine to finish without deadlocking;
 201  * the lock is then reclaimed to allow caller to release it upon return.
 202  *
 203  * Note that fields of 's' use subscriber's endianness!
 204  */
 205 static void tipc_subscrp_cancel(struct tipc_subscr *s,
 206                                 struct tipc_subscriber *subscriber)
 207 {
 208         struct tipc_subscription *sub;
 209         struct tipc_subscription *sub_temp;
 210         int found = 0;
 211
 212         /* Find first matching subscription, exit if not found */
 213         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscrp_list,
 214                                  subscrp_list) {
 215                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 216                         found = 1;
 217                         break;
 218                 }
 219         }
 220         if (!found)
 221                 return;
 222
 223         /* Cancel subscription timer (if used), then delete subscription */
 224         if (sub->timeout != TIPC_WAIT_FOREVER) {
 225                 sub->timeout = TIPC_WAIT_FOREVER;
 226                 spin_unlock_bh(&subscriber->lock);
 227                 del_timer_sync(&sub->timer);
 228                 spin_lock_bh(&subscriber->lock);
 229         }
 230         tipc_subscrp_delete(sub);
 231 }
 232
 233 static int tipc_subscrp_create(struct net *net, struct tipc_subscr *s,
 234                                struct tipc_subscriber *subscriber,
 235                                struct tipc_subscription **sub_p)
 236 {
 237         struct tipc_net *tn = net_generic(net, tipc_net_id);
 238         struct tipc_subscription *sub;
 239         int swap;
 240
 241         /* Determine subscriber's endianness */
 242         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 243
 244         /* Detect & process a subscription cancellation request */
 245         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 246                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 247                 tipc_subscrp_cancel(s, subscriber);
 248                 return 0;
 249         }
 250
 251         /* Refuse subscription if global limit exceeded */
 252         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 253                 pr_warn("Subscription rejected, limit reached (%u)\n",
 254                         TIPC_MAX_SUBSCRIPTIONS);
 255                 return -EINVAL;
 256         }
 257
 258         /* Allocate subscription object */
 259         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 260         if (!sub) {
 261                 pr_warn("Subscription rejected, no memory\n");
 262                 return -ENOMEM;
 263         }
 264
 265         /* Initialize subscription object */
 266         sub->net = net;
 267         sub->seq.type = htohl(s->seq.type, swap);
 268         sub->seq.lower = htohl(s->seq.lower, swap);
 269         sub->seq.upper = htohl(s->seq.upper, swap);
 270         sub->timeout = msecs_to_jiffies(htohl(s->timeout, swap));
 271         sub->filter = htohl(s->filter, swap);
 272         if ((!(sub->filter & TIPC_SUB_PORTS) ==
 273              !(sub->filter & TIPC_SUB_SERVICE)) ||
 274             (sub->seq.lower > sub->seq.upper)) {
 275                 pr_warn("Subscription rejected, illegal request\n");
 276                 kfree(sub);
 277                 return -EINVAL;
 278         }
 279         list_add(&sub->subscrp_list, &subscriber->subscrp_list);
 280         sub->subscriber = subscriber;
 281         sub->swap = swap;
 282         memcpy(&sub->evt.s, s, sizeof(*s));
 283         atomic_inc(&tn->subscription_count);
 284         if (sub->timeout != TIPC_WAIT_FOREVER) {
 285                 setup_timer(&sub->timer, tipc_subscrp_timeout,
 286                             (unsigned long)sub);
 287                 mod_timer(&sub->timer, jiffies + sub->timeout);
 288         }
 289         *sub_p = sub;
 290         return 0;
 291 }
 292
 293 /* Handle one termination request for the subscriber */
 294 static void tipc_subscrb_shutdown_cb(int conid, void *usr_data)
 295 {
 296         tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
 297 }
 298
 299 /* Handle one request to create a new subscription for the subscriber */
 300 static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 301                                 struct sockaddr_tipc *addr, void *usr_data,
 302                                 void *buf, size_t len)
 303 {
 304         struct tipc_subscriber *subscriber = usr_data;
 305         struct tipc_subscription *sub = NULL;
 306         struct tipc_net *tn = net_generic(net, tipc_net_id);
 307
 308         spin_lock_bh(&subscriber->lock);
 309         tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscriber, &sub);
 310         if (sub)
 311                 tipc_nametbl_subscribe(sub);
 312         else
 313                 tipc_conn_terminate(tn->topsrv, subscriber->conid);
 314         spin_unlock_bh(&subscriber->lock);
 315 }
 316
 317 /* Handle one request to establish a new subscriber */
 318 static void *tipc_subscrb_connect_cb(int conid)
 319 {
 320         return (void *)tipc_subscrb_create(conid);
 321 }
 322
 323 int tipc_topsrv_start(struct net *net)
 324 {
 325         struct tipc_net *tn = net_generic(net, tipc_net_id);
 326         const char name[] = "topology_server";
 327         struct tipc_server *topsrv;
 328         struct sockaddr_tipc *saddr;
 329
 330         saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
 331         if (!saddr)
 332                 return -ENOMEM;
 333         saddr->family                   = AF_TIPC;
 334         saddr->addrtype                 = TIPC_ADDR_NAMESEQ;
 335         saddr->addr.nameseq.type        = TIPC_TOP_SRV;
 336         saddr->addr.nameseq.lower       = TIPC_TOP_SRV;
 337         saddr->addr.nameseq.upper       = TIPC_TOP_SRV;
 338         saddr->scope                    = TIPC_NODE_SCOPE;
 339
 340         topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
 341         if (!topsrv) {
 342                 kfree(saddr);
 343                 return -ENOMEM;
 344         }
 345         topsrv->net                     = net;
 346         topsrv->saddr                   = saddr;
 347         topsrv->imp                     = TIPC_CRITICAL_IMPORTANCE;
 348         topsrv->type                    = SOCK_SEQPACKET;
 349         topsrv->max_rcvbuf_size         = sizeof(struct tipc_subscr);
 350         topsrv->tipc_conn_recvmsg       = tipc_subscrb_rcv_cb;
 351         topsrv->tipc_conn_new           = tipc_subscrb_connect_cb;
 352         topsrv->tipc_conn_shutdown      = tipc_subscrb_shutdown_cb;
 353
 354         strncpy(topsrv->name, name, strlen(name) + 1);
 355         tn->topsrv = topsrv;
 356         atomic_set(&tn->subscription_count, 0);
 357
 358         return tipc_server_start(topsrv);
 359 }
 360
 361 void tipc_topsrv_stop(struct net *net)
 362 {
 363         struct tipc_net *tn = net_generic(net, tipc_net_id);
 364         struct tipc_server *topsrv = tn->topsrv;
 365
 366         tipc_server_stop(topsrv);
 367         kfree(topsrv->saddr);
 368         kfree(topsrv);
 369 }