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 void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
 158 {
 159         struct tipc_subscription *sub;
 160         struct tipc_subscription *sub_temp;
 161
 162         spin_lock_bh(&subscriber->lock);
 163
 164         /* Destroy any existing subscriptions for subscriber */
 165         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscrp_list,
 166                                  subscrp_list) {
 167                 if (sub->timeout != TIPC_WAIT_FOREVER) {
 168                         spin_unlock_bh(&subscriber->lock);
 169                         del_timer_sync(&sub->timer);
 170                         spin_lock_bh(&subscriber->lock);
 171                 }
 172                 tipc_subscrp_delete(sub);
 173         }
 174         spin_unlock_bh(&subscriber->lock);
 175
 176         /* Now destroy subscriber */
 177         kfree(subscriber);
 178 }
 179
 180 /**
 181  * tipc_subscrp_cancel - handle subscription cancellation request
 182  *
 183  * Called with subscriber lock held. Routine must temporarily release lock
 184  * to enable the subscription timeout routine to finish without deadlocking;
 185  * the lock is then reclaimed to allow caller to release it upon return.
 186  *
 187  * Note that fields of 's' use subscriber's endianness!
 188  */
 189 static void tipc_subscrp_cancel(struct tipc_subscr *s,
 190                                 struct tipc_subscriber *subscriber)
 191 {
 192         struct tipc_subscription *sub;
 193         struct tipc_subscription *sub_temp;
 194         int found = 0;
 195
 196         /* Find first matching subscription, exit if not found */
 197         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscrp_list,
 198                                  subscrp_list) {
 199                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 200                         found = 1;
 201                         break;
 202                 }
 203         }
 204         if (!found)
 205                 return;
 206
 207         /* Cancel subscription timer (if used), then delete subscription */
 208         if (sub->timeout != TIPC_WAIT_FOREVER) {
 209                 sub->timeout = TIPC_WAIT_FOREVER;
 210                 spin_unlock_bh(&subscriber->lock);
 211                 del_timer_sync(&sub->timer);
 212                 spin_lock_bh(&subscriber->lock);
 213         }
 214         tipc_subscrp_delete(sub);
 215 }
 216
 217 static int tipc_subscrp_create(struct net *net, struct tipc_subscr *s,
 218                                struct tipc_subscriber *subscriber,
 219                                struct tipc_subscription **sub_p)
 220 {
 221         struct tipc_net *tn = net_generic(net, tipc_net_id);
 222         struct tipc_subscription *sub;
 223         int swap;
 224
 225         /* Determine subscriber's endianness */
 226         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
 227
 228         /* Detect & process a subscription cancellation request */
 229         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 230                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 231                 tipc_subscrp_cancel(s, subscriber);
 232                 return 0;
 233         }
 234
 235         /* Refuse subscription if global limit exceeded */
 236         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 237                 pr_warn("Subscription rejected, limit reached (%u)\n",
 238                         TIPC_MAX_SUBSCRIPTIONS);
 239                 return -EINVAL;
 240         }
 241
 242         /* Allocate subscription object */
 243         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 244         if (!sub) {
 245                 pr_warn("Subscription rejected, no memory\n");
 246                 return -ENOMEM;
 247         }
 248
 249         /* Initialize subscription object */
 250         sub->net = net;
 251         sub->seq.type = htohl(s->seq.type, swap);
 252         sub->seq.lower = htohl(s->seq.lower, swap);
 253         sub->seq.upper = htohl(s->seq.upper, swap);
 254         sub->timeout = msecs_to_jiffies(htohl(s->timeout, swap));
 255         sub->filter = htohl(s->filter, swap);
 256         if ((!(sub->filter & TIPC_SUB_PORTS) ==
 257              !(sub->filter & TIPC_SUB_SERVICE)) ||
 258             (sub->seq.lower > sub->seq.upper)) {
 259                 pr_warn("Subscription rejected, illegal request\n");
 260                 kfree(sub);
 261                 return -EINVAL;
 262         }
 263         list_add(&sub->subscrp_list, &subscriber->subscrp_list);
 264         sub->subscriber = subscriber;
 265         sub->swap = swap;
 266         memcpy(&sub->evt.s, s, sizeof(*s));
 267         atomic_inc(&tn->subscription_count);
 268         if (sub->timeout != TIPC_WAIT_FOREVER) {
 269                 setup_timer(&sub->timer, tipc_subscrp_timeout,
 270                             (unsigned long)sub);
 271                 mod_timer(&sub->timer, jiffies + sub->timeout);
 272         }
 273         *sub_p = sub;
 274         return 0;
 275 }
 276
 277 /* Handle one termination request for the subscriber */
 278 static void tipc_subscrb_shutdown_cb(int conid, void *usr_data)
 279 {
 280         tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
 281 }
 282
 283 /* Handle one request to create a new subscription for the subscriber */
 284 static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 285                                 struct sockaddr_tipc *addr, void *usr_data,
 286                                 void *buf, size_t len)
 287 {
 288         struct tipc_subscriber *subscriber = usr_data;
 289         struct tipc_subscription *sub = NULL;
 290         struct tipc_net *tn = net_generic(net, tipc_net_id);
 291
 292         spin_lock_bh(&subscriber->lock);
 293         tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscriber, &sub);
 294         if (sub)
 295                 tipc_nametbl_subscribe(sub);
 296         else
 297                 tipc_conn_terminate(tn->topsrv, subscriber->conid);
 298         spin_unlock_bh(&subscriber->lock);
 299 }
 300
 301 /* Handle one request to establish a new subscriber */
 302 static void *tipc_subscrb_connect_cb(int conid)
 303 {
 304         struct tipc_subscriber *subscriber;
 305
 306         /* Create subscriber object */
 307         subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
 308         if (subscriber == NULL) {
 309                 pr_warn("Subscriber rejected, no memory\n");
 310                 return NULL;
 311         }
 312         INIT_LIST_HEAD(&subscriber->subscrp_list);
 313         subscriber->conid = conid;
 314         spin_lock_init(&subscriber->lock);
 315
 316         return (void *)subscriber;
 317 }
 318
 319 int tipc_topsrv_start(struct net *net)
 320 {
 321         struct tipc_net *tn = net_generic(net, tipc_net_id);
 322         const char name[] = "topology_server";
 323         struct tipc_server *topsrv;
 324         struct sockaddr_tipc *saddr;
 325
 326         saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
 327         if (!saddr)
 328                 return -ENOMEM;
 329         saddr->family                   = AF_TIPC;
 330         saddr->addrtype                 = TIPC_ADDR_NAMESEQ;
 331         saddr->addr.nameseq.type        = TIPC_TOP_SRV;
 332         saddr->addr.nameseq.lower       = TIPC_TOP_SRV;
 333         saddr->addr.nameseq.upper       = TIPC_TOP_SRV;
 334         saddr->scope                    = TIPC_NODE_SCOPE;
 335
 336         topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
 337         if (!topsrv) {
 338                 kfree(saddr);
 339                 return -ENOMEM;
 340         }
 341         topsrv->net                     = net;
 342         topsrv->saddr                   = saddr;
 343         topsrv->imp                     = TIPC_CRITICAL_IMPORTANCE;
 344         topsrv->type                    = SOCK_SEQPACKET;
 345         topsrv->max_rcvbuf_size         = sizeof(struct tipc_subscr);
 346         topsrv->tipc_conn_recvmsg       = tipc_subscrb_rcv_cb;
 347         topsrv->tipc_conn_new           = tipc_subscrb_connect_cb;
 348         topsrv->tipc_conn_shutdown      = tipc_subscrb_shutdown_cb;
 349
 350         strncpy(topsrv->name, name, strlen(name) + 1);
 351         tn->topsrv = topsrv;
 352         atomic_set(&tn->subscription_count, 0);
 353
 354         return tipc_server_start(topsrv);
 355 }
 356
 357 void tipc_topsrv_stop(struct net *net)
 358 {
 359         struct tipc_net *tn = net_generic(net, tipc_net_id);
 360         struct tipc_server *topsrv = tn->topsrv;
 361
 362         tipc_server_stop(topsrv);
 363         kfree(topsrv->saddr);
 364         kfree(topsrv);
 365 }