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_name_seq *seq, u32 found_lower,
  96                                u32 found_upper)
  97 {
  98         if (found_lower < seq->lower)
  99                 found_lower = seq->lower;
 100         if (found_upper > seq->upper)
 101                 found_upper = seq->upper;
 102         if (found_lower > found_upper)
 103                 return 0;
 104         return 1;
 105 }
 106
 107 u32 tipc_subscrp_convert_seq_type(u32 type, int swap)
 108 {
 109         return htohl(type, swap);
 110 }
 111
 112 void tipc_subscrp_convert_seq(struct tipc_name_seq *in, int swap,
 113                               struct tipc_name_seq *out)
 114 {
 115         out->type = htohl(in->type, swap);
 116         out->lower = htohl(in->lower, swap);
 117         out->upper = htohl(in->upper, swap);
 118 }
 119
 120 void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 121                                  u32 found_upper, u32 event, u32 port_ref,
 122                                  u32 node, int must)
 123 {
 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 &&
 130             !(htohl(sub->evt.s.filter, sub->swap) & TIPC_SUB_PORTS))
 131                 return;
 132
 133         tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
 134                                 node);
 135 }
 136
 137 static void tipc_subscrp_timeout(unsigned long data)
 138 {
 139         struct tipc_subscription *sub = (struct tipc_subscription *)data;
 140         struct tipc_subscriber *subscriber = sub->subscriber;
 141
 142         /* Notify subscriber of timeout */
 143         tipc_subscrp_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 144                                 TIPC_SUBSCR_TIMEOUT, 0, 0);
 145
 146         spin_lock_bh(&subscriber->lock);
 147         tipc_subscrp_delete(sub);
 148         spin_unlock_bh(&subscriber->lock);
 149
 150         tipc_subscrb_put(subscriber);
 151 }
 152
 153 static void tipc_subscrb_kref_release(struct kref *kref)
 154 {
 155         struct tipc_subscriber *subcriber = container_of(kref,
 156                                             struct tipc_subscriber, kref);
 157
 158         kfree(subcriber);
 159 }
 160
 161 static void tipc_subscrb_put(struct tipc_subscriber *subscriber)
 162 {
 163         kref_put(&subscriber->kref, tipc_subscrb_kref_release);
 164 }
 165
 166 static void tipc_subscrb_get(struct tipc_subscriber *subscriber)
 167 {
 168         kref_get(&subscriber->kref);
 169 }
 170
 171 static struct tipc_subscriber *tipc_subscrb_create(int conid)
 172 {
 173         struct tipc_subscriber *subscriber;
 174
 175         subscriber = kzalloc(sizeof(*subscriber), GFP_ATOMIC);
 176         if (!subscriber) {
 177                 pr_warn("Subscriber rejected, no memory\n");
 178                 return NULL;
 179         }
 180         kref_init(&subscriber->kref);
 181         INIT_LIST_HEAD(&subscriber->subscrp_list);
 182         subscriber->conid = conid;
 183         spin_lock_init(&subscriber->lock);
 184
 185         return subscriber;
 186 }
 187
 188 static void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
 189 {
 190         struct tipc_subscription *sub, *temp;
 191
 192         spin_lock_bh(&subscriber->lock);
 193         /* Destroy any existing subscriptions for subscriber */
 194         list_for_each_entry_safe(sub, temp, &subscriber->subscrp_list,
 195                                  subscrp_list) {
 196                 if (del_timer(&sub->timer)) {
 197                         tipc_subscrp_delete(sub);
 198                         tipc_subscrb_put(subscriber);
 199                 }
 200         }
 201         spin_unlock_bh(&subscriber->lock);
 202
 203         tipc_subscrb_put(subscriber);
 204 }
 205
 206 static void tipc_subscrp_delete(struct tipc_subscription *sub)
 207 {
 208         struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 209
 210         tipc_nametbl_unsubscribe(sub);
 211         list_del(&sub->subscrp_list);
 212         kfree(sub);
 213         atomic_dec(&tn->subscription_count);
 214 }
 215
 216 static void tipc_subscrp_cancel(struct tipc_subscr *s,
 217                                 struct tipc_subscriber *subscriber)
 218 {
 219         struct tipc_subscription *sub, *temp;
 220
 221         spin_lock_bh(&subscriber->lock);
 222         /* Find first matching subscription, exit if not found */
 223         list_for_each_entry_safe(sub, temp, &subscriber->subscrp_list,
 224                                  subscrp_list) {
 225                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 226                         if (del_timer(&sub->timer)) {
 227                                 tipc_subscrp_delete(sub);
 228                                 tipc_subscrb_put(subscriber);
 229                         }
 230                         break;
 231                 }
 232         }
 233         spin_unlock_bh(&subscriber->lock);
 234 }
 235
 236 static struct tipc_subscription *tipc_subscrp_create(struct net *net,
 237                                                      struct tipc_subscr *s,
 238                                                      int swap)
 239 {
 240         struct tipc_net *tn = net_generic(net, tipc_net_id);
 241         struct tipc_subscription *sub;
 242         u32 filter = htohl(s->filter, swap);
 243
 244         /* Refuse subscription if global limit exceeded */
 245         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
 246                 pr_warn("Subscription rejected, limit reached (%u)\n",
 247                         TIPC_MAX_SUBSCRIPTIONS);
 248                 return NULL;
 249         }
 250
 251         /* Allocate subscription object */
 252         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 253         if (!sub) {
 254                 pr_warn("Subscription rejected, no memory\n");
 255                 return NULL;
 256         }
 257
 258         /* Initialize subscription object */
 259         sub->net = net;
 260         if (((filter & TIPC_SUB_PORTS) && (filter & TIPC_SUB_SERVICE)) ||
 261             (htohl(s->seq.lower, swap) > htohl(s->seq.upper, swap))) {
 262                 pr_warn("Subscription rejected, illegal request\n");
 263                 kfree(sub);
 264                 return NULL;
 265         }
 266
 267         sub->swap = swap;
 268         memcpy(&sub->evt.s, s, sizeof(*s));
 269         atomic_inc(&tn->subscription_count);
 270         setup_timer(&sub->timer, tipc_subscrp_timeout, (unsigned long)sub);
 271         return sub;
 272 }
 273
 274 static void tipc_subscrp_subscribe(struct net *net, struct tipc_subscr *s,
 275                                    struct tipc_subscriber *subscriber, int swap)
 276 {
 277         struct tipc_net *tn = net_generic(net, tipc_net_id);
 278         struct tipc_subscription *sub = NULL;
 279         u32 timeout;
 280
 281         sub = tipc_subscrp_create(net, s, swap);
 282         if (!sub)
 283                 return tipc_conn_terminate(tn->topsrv, subscriber->conid);
 284
 285         spin_lock_bh(&subscriber->lock);
 286         list_add(&sub->subscrp_list, &subscriber->subscrp_list);
 287         spin_unlock_bh(&subscriber->lock);
 288
 289         sub->subscriber = subscriber;
 290         timeout = htohl(sub->evt.s.timeout, swap);
 291         if (!mod_timer(&sub->timer, jiffies + msecs_to_jiffies(timeout)))
 292                 tipc_subscrb_get(subscriber);
 293         tipc_nametbl_subscribe(sub);
 294 }
 295
 296 /* Handle one termination request for the subscriber */
 297 static void tipc_subscrb_shutdown_cb(int conid, void *usr_data)
 298 {
 299         tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
 300 }
 301
 302 /* Handle one request to create a new subscription for the subscriber */
 303 static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 304                                 struct sockaddr_tipc *addr, void *usr_data,
 305                                 void *buf, size_t len)
 306 {
 307         struct tipc_subscriber *subscriber = usr_data;
 308         struct tipc_subscr *s = (struct tipc_subscr *)buf;
 309         int swap;
 310
 311         /* Determine subscriber's endianness */
 312         swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE |
 313                               TIPC_SUB_CANCEL));
 314
 315         /* Detect & process a subscription cancellation request */
 316         if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 317                 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 318                 return tipc_subscrp_cancel(s, subscriber);
 319         }
 320
 321         tipc_subscrp_subscribe(net, s, subscriber, swap);
 322 }
 323
 324 /* Handle one request to establish a new subscriber */
 325 static void *tipc_subscrb_connect_cb(int conid)
 326 {
 327         return (void *)tipc_subscrb_create(conid);
 328 }
 329
 330 int tipc_topsrv_start(struct net *net)
 331 {
 332         struct tipc_net *tn = net_generic(net, tipc_net_id);
 333         const char name[] = "topology_server";
 334         struct tipc_server *topsrv;
 335         struct sockaddr_tipc *saddr;
 336
 337         saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
 338         if (!saddr)
 339                 return -ENOMEM;
 340         saddr->family                   = AF_TIPC;
 341         saddr->addrtype                 = TIPC_ADDR_NAMESEQ;
 342         saddr->addr.nameseq.type        = TIPC_TOP_SRV;
 343         saddr->addr.nameseq.lower       = TIPC_TOP_SRV;
 344         saddr->addr.nameseq.upper       = TIPC_TOP_SRV;
 345         saddr->scope                    = TIPC_NODE_SCOPE;
 346
 347         topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
 348         if (!topsrv) {
 349                 kfree(saddr);
 350                 return -ENOMEM;
 351         }
 352         topsrv->net                     = net;
 353         topsrv->saddr                   = saddr;
 354         topsrv->imp                     = TIPC_CRITICAL_IMPORTANCE;
 355         topsrv->type                    = SOCK_SEQPACKET;
 356         topsrv->max_rcvbuf_size         = sizeof(struct tipc_subscr);
 357         topsrv->tipc_conn_recvmsg       = tipc_subscrb_rcv_cb;
 358         topsrv->tipc_conn_new           = tipc_subscrb_connect_cb;
 359         topsrv->tipc_conn_shutdown      = tipc_subscrb_shutdown_cb;
 360
 361         strncpy(topsrv->name, name, strlen(name) + 1);
 362         tn->topsrv = topsrv;
 363         atomic_set(&tn->subscription_count, 0);
 364
 365         return tipc_server_start(topsrv);
 366 }
 367
 368 void tipc_topsrv_stop(struct net *net)
 369 {
 370         struct tipc_net *tn = net_generic(net, tipc_net_id);
 371         struct tipc_server *topsrv = tn->topsrv;
 372
 373         tipc_server_stop(topsrv);
 374         kfree(topsrv->saddr);
 375         kfree(topsrv);
 376 }