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