net/tipc/topsrv.c

   1 /*
   2  * net/tipc/server.c: TIPC server infrastructure
   3  *
   4  * Copyright (c) 2012-2013, Wind River Systems
   5  * Copyright (c) 2017-2018, Ericsson AB
   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 "subscr.h"
  38 #include "topsrv.h"
  39 #include "core.h"
  40 #include "socket.h"
  41 #include "addr.h"
  42 #include "msg.h"
  43 #include <net/sock.h>
  44 #include <linux/module.h>
  45
  46 /* Number of messages to send before rescheduling */
  47 #define MAX_SEND_MSG_COUNT      25
  48 #define MAX_RECV_MSG_COUNT      25
  49 #define CF_CONNECTED            1
  50 #define CF_SERVER               2
  51
  52 #define TIPC_SERVER_NAME_LEN    32
  53
  54 /**
  55  * struct tipc_topsrv - TIPC server structure
  56  * @conn_idr: identifier set of connection
  57  * @idr_lock: protect the connection identifier set
  58  * @idr_in_use: amount of allocated identifier entry
  59  * @net: network namspace instance
  60  * @rcvbuf_cache: memory cache of server receive buffer
  61  * @rcv_wq: receive workqueue
  62  * @send_wq: send workqueue
  63  * @max_rcvbuf_size: maximum permitted receive message length
  64  * @tipc_conn_new: callback will be called when new connection is incoming
  65  * @tipc_conn_release: callback will be called before releasing the connection
  66  * @tipc_conn_recvmsg: callback will be called when message arrives
  67  * @name: server name
  68  * @imp: message importance
  69  * @type: socket type
  70  */
  71 struct tipc_topsrv {
  72         struct idr conn_idr;
  73         spinlock_t idr_lock; /* for idr list */
  74         int idr_in_use;
  75         struct net *net;
  76         struct work_struct awork;
  77         struct workqueue_struct *rcv_wq;
  78         struct workqueue_struct *send_wq;
  79         int max_rcvbuf_size;
  80         struct socket *listener;
  81         char name[TIPC_SERVER_NAME_LEN];
  82 };
  83
  84 /**
  85  * struct tipc_conn - TIPC connection structure
  86  * @kref: reference counter to connection object
  87  * @conid: connection identifier
  88  * @sock: socket handler associated with connection
  89  * @flags: indicates connection state
  90  * @server: pointer to connected server
  91  * @sub_list: lsit to all pertaing subscriptions
  92  * @sub_lock: lock protecting the subscription list
  93  * @outqueue_lock: control access to the outqueue
  94  * @rwork: receive work item
  95  * @rx_action: what to do when connection socket is active
  96  * @outqueue: pointer to first outbound message in queue
  97  * @outqueue_lock: control access to the outqueue
  98  * @swork: send work item
  99  */
 100 struct tipc_conn {
 101         struct kref kref;
 102         int conid;
 103         struct socket *sock;
 104         unsigned long flags;
 105         struct tipc_topsrv *server;
 106         struct list_head sub_list;
 107         spinlock_t sub_lock; /* for subscription list */
 108         struct work_struct rwork;
 109         struct list_head outqueue;
 110         spinlock_t outqueue_lock; /* for outqueue */
 111         struct work_struct swork;
 112 };
 113
 114 /* An entry waiting to be sent */
 115 struct outqueue_entry {
 116         bool inactive;
 117         struct tipc_event evt;
 118         struct list_head list;
 119 };
 120
 121 static void tipc_conn_recv_work(struct work_struct *work);
 122 static void tipc_conn_send_work(struct work_struct *work);
 123 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
 124 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
 125
 126 static bool connected(struct tipc_conn *con)
 127 {
 128         return con && test_bit(CF_CONNECTED, &con->flags);
 129 }
 130
 131 static void tipc_conn_kref_release(struct kref *kref)
 132 {
 133         struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
 134         struct tipc_topsrv *s = con->server;
 135         struct outqueue_entry *e, *safe;
 136
 137         spin_lock_bh(&s->idr_lock);
 138         idr_remove(&s->conn_idr, con->conid);
 139         s->idr_in_use--;
 140         spin_unlock_bh(&s->idr_lock);
 141         if (con->sock)
 142                 sock_release(con->sock);
 143
 144         spin_lock_bh(&con->outqueue_lock);
 145         list_for_each_entry_safe(e, safe, &con->outqueue, list) {
 146                 list_del(&e->list);
 147                 kfree(e);
 148         }
 149         spin_unlock_bh(&con->outqueue_lock);
 150         kfree(con);
 151 }
 152
 153 static void conn_put(struct tipc_conn *con)
 154 {
 155         kref_put(&con->kref, tipc_conn_kref_release);
 156 }
 157
 158 static void conn_get(struct tipc_conn *con)
 159 {
 160         kref_get(&con->kref);
 161 }
 162
 163 static void tipc_conn_close(struct tipc_conn *con)
 164 {
 165         struct sock *sk = con->sock->sk;
 166         bool disconnect = false;
 167
 168         write_lock_bh(&sk->sk_callback_lock);
 169         disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
 170
 171         if (disconnect) {
 172                 sk->sk_user_data = NULL;
 173                 tipc_conn_delete_sub(con, NULL);
 174         }
 175         write_unlock_bh(&sk->sk_callback_lock);
 176
 177         /* Handle concurrent calls from sending and receiving threads */
 178         if (!disconnect)
 179                 return;
 180
 181         /* Don't flush pending works, -just let them expire */
 182         kernel_sock_shutdown(con->sock, SHUT_RDWR);
 183
 184         conn_put(con);
 185 }
 186
 187 static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
 188 {
 189         struct tipc_conn *con;
 190         int ret;
 191
 192         con = kzalloc(sizeof(*con), GFP_ATOMIC);
 193         if (!con)
 194                 return ERR_PTR(-ENOMEM);
 195
 196         kref_init(&con->kref);
 197         INIT_LIST_HEAD(&con->outqueue);
 198         INIT_LIST_HEAD(&con->sub_list);
 199         spin_lock_init(&con->outqueue_lock);
 200         spin_lock_init(&con->sub_lock);
 201         INIT_WORK(&con->swork, tipc_conn_send_work);
 202         INIT_WORK(&con->rwork, tipc_conn_recv_work);
 203
 204         spin_lock_bh(&s->idr_lock);
 205         ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
 206         if (ret < 0) {
 207                 kfree(con);
 208                 spin_unlock_bh(&s->idr_lock);
 209                 return ERR_PTR(-ENOMEM);
 210         }
 211         con->conid = ret;
 212         s->idr_in_use++;
 213         spin_unlock_bh(&s->idr_lock);
 214
 215         set_bit(CF_CONNECTED, &con->flags);
 216         con->server = s;
 217
 218         return con;
 219 }
 220
 221 static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
 222 {
 223         struct tipc_conn *con;
 224
 225         spin_lock_bh(&s->idr_lock);
 226         con = idr_find(&s->conn_idr, conid);
 227         if (!connected(con) || !kref_get_unless_zero(&con->kref))
 228                 con = NULL;
 229         spin_unlock_bh(&s->idr_lock);
 230         return con;
 231 }
 232
 233 /* tipc_conn_delete_sub - delete a specific or all subscriptions
 234  * for a given subscriber
 235  */
 236 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
 237 {
 238         struct tipc_net *tn = tipc_net(con->server->net);
 239         struct list_head *sub_list = &con->sub_list;
 240         struct tipc_subscription *sub, *tmp;
 241
 242         spin_lock_bh(&con->sub_lock);
 243         list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
 244                 if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
 245                         tipc_sub_unsubscribe(sub);
 246                         atomic_dec(&tn->subscription_count);
 247                 } else if (s) {
 248                         break;
 249                 }
 250         }
 251         spin_unlock_bh(&con->sub_lock);
 252 }
 253
 254 static void tipc_conn_send_to_sock(struct tipc_conn *con)
 255 {
 256         struct list_head *queue = &con->outqueue;
 257         struct tipc_topsrv *srv = con->server;
 258         struct outqueue_entry *e;
 259         struct tipc_event *evt;
 260         struct msghdr msg;
 261         struct kvec iov;
 262         int count = 0;
 263         int ret;
 264
 265         spin_lock_bh(&con->outqueue_lock);
 266
 267         while (!list_empty(queue)) {
 268                 e = list_first_entry(queue, struct outqueue_entry, list);
 269                 evt = &e->evt;
 270                 spin_unlock_bh(&con->outqueue_lock);
 271
 272                 if (e->inactive)
 273                         tipc_conn_delete_sub(con, &evt->s);
 274
 275                 memset(&msg, 0, sizeof(msg));
 276                 msg.msg_flags = MSG_DONTWAIT;
 277                 iov.iov_base = evt;
 278                 iov.iov_len = sizeof(*evt);
 279                 msg.msg_name = NULL;
 280
 281                 if (con->sock) {
 282                         ret = kernel_sendmsg(con->sock, &msg, &iov,
 283                                              1, sizeof(*evt));
 284                         if (ret == -EWOULDBLOCK || ret == 0) {
 285                                 cond_resched();
 286                                 return;
 287                         } else if (ret < 0) {
 288                                 return tipc_conn_close(con);
 289                         }
 290                 } else {
 291                         tipc_topsrv_kern_evt(srv->net, evt);
 292                 }
 293
 294                 /* Don't starve users filling buffers */
 295                 if (++count >= MAX_SEND_MSG_COUNT) {
 296                         cond_resched();
 297                         count = 0;
 298                 }
 299                 spin_lock_bh(&con->outqueue_lock);
 300                 list_del(&e->list);
 301                 kfree(e);
 302         }
 303         spin_unlock_bh(&con->outqueue_lock);
 304 }
 305
 306 static void tipc_conn_send_work(struct work_struct *work)
 307 {
 308         struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
 309
 310         if (connected(con))
 311                 tipc_conn_send_to_sock(con);
 312
 313         conn_put(con);
 314 }
 315
 316 /* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
 317  * The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
 318  */
 319 void tipc_topsrv_queue_evt(struct net *net, int conid,
 320                            u32 event, struct tipc_event *evt)
 321 {
 322         struct tipc_topsrv *srv = tipc_topsrv(net);
 323         struct outqueue_entry *e;
 324         struct tipc_conn *con;
 325
 326         con = tipc_conn_lookup(srv, conid);
 327         if (!con)
 328                 return;
 329
 330         if (!connected(con))
 331                 goto err;
 332
 333         e = kmalloc(sizeof(*e), GFP_ATOMIC);
 334         if (!e)
 335                 goto err;
 336         e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
 337         memcpy(&e->evt, evt, sizeof(*evt));
 338         spin_lock_bh(&con->outqueue_lock);
 339         list_add_tail(&e->list, &con->outqueue);
 340         spin_unlock_bh(&con->outqueue_lock);
 341
 342         if (queue_work(srv->send_wq, &con->swork))
 343                 return;
 344 err:
 345         conn_put(con);
 346 }
 347
 348 /* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
 349  * Indicates that there now is more space in the send buffer
 350  * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
 351  */
 352 static void tipc_conn_write_space(struct sock *sk)
 353 {
 354         struct tipc_conn *con;
 355
 356         read_lock_bh(&sk->sk_callback_lock);
 357         con = sk->sk_user_data;
 358         if (connected(con)) {
 359                 conn_get(con);
 360                 if (!queue_work(con->server->send_wq, &con->swork))
 361                         conn_put(con);
 362         }
 363         read_unlock_bh(&sk->sk_callback_lock);
 364 }
 365
 366 static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
 367                              struct tipc_conn *con,
 368                              struct tipc_subscr *s)
 369 {
 370         struct tipc_net *tn = tipc_net(srv->net);
 371         struct tipc_subscription *sub;
 372
 373         if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
 374                 tipc_conn_delete_sub(con, s);
 375                 return 0;
 376         }
 377         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
 378                 pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
 379                 return -1;
 380         }
 381         sub = tipc_sub_subscribe(srv->net, s, con->conid);
 382         if (!sub)
 383                 return -1;
 384         atomic_inc(&tn->subscription_count);
 385         spin_lock_bh(&con->sub_lock);
 386         list_add(&sub->sub_list, &con->sub_list);
 387         spin_unlock_bh(&con->sub_lock);
 388         return 0;
 389 }
 390
 391 static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
 392 {
 393         struct tipc_topsrv *srv = con->server;
 394         struct sock *sk = con->sock->sk;
 395         struct msghdr msg = {};
 396         struct tipc_subscr s;
 397         struct kvec iov;
 398         int ret;
 399
 400         iov.iov_base = &s;
 401         iov.iov_len = sizeof(s);
 402         msg.msg_name = NULL;
 403         iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &iov, 1, iov.iov_len);
 404         ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
 405         if (ret == -EWOULDBLOCK)
 406                 return -EWOULDBLOCK;
 407         if (ret == sizeof(s)) {
 408                 read_lock_bh(&sk->sk_callback_lock);
 409                 ret = tipc_conn_rcv_sub(srv, con, &s);
 410                 read_unlock_bh(&sk->sk_callback_lock);
 411         }
 412         if (ret < 0)
 413                 tipc_conn_close(con);
 414
 415         return ret;
 416 }
 417
 418 static void tipc_conn_recv_work(struct work_struct *work)
 419 {
 420         struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
 421         int count = 0;
 422
 423         while (connected(con)) {
 424                 if (tipc_conn_rcv_from_sock(con))
 425                         break;
 426
 427                 /* Don't flood Rx machine */
 428                 if (++count >= MAX_RECV_MSG_COUNT) {
 429                         cond_resched();
 430                         count = 0;
 431                 }
 432         }
 433         conn_put(con);
 434 }
 435
 436 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
 437  * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
 438  */
 439 static void tipc_conn_data_ready(struct sock *sk)
 440 {
 441         struct tipc_conn *con;
 442
 443         read_lock_bh(&sk->sk_callback_lock);
 444         con = sk->sk_user_data;
 445         if (connected(con)) {
 446                 conn_get(con);
 447                 if (!queue_work(con->server->rcv_wq, &con->rwork))
 448                         conn_put(con);
 449         }
 450         read_unlock_bh(&sk->sk_callback_lock);
 451 }
 452
 453 static void tipc_topsrv_accept(struct work_struct *work)
 454 {
 455         struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
 456         struct socket *lsock = srv->listener;
 457         struct socket *newsock;
 458         struct tipc_conn *con;
 459         struct sock *newsk;
 460         int ret;
 461
 462         while (1) {
 463                 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
 464                 if (ret < 0)
 465                         return;
 466                 con = tipc_conn_alloc(srv);
 467                 if (IS_ERR(con)) {
 468                         ret = PTR_ERR(con);
 469                         sock_release(newsock);
 470                         return;
 471                 }
 472                 /* Register callbacks */
 473                 newsk = newsock->sk;
 474                 write_lock_bh(&newsk->sk_callback_lock);
 475                 newsk->sk_data_ready = tipc_conn_data_ready;
 476                 newsk->sk_write_space = tipc_conn_write_space;
 477                 newsk->sk_user_data = con;
 478                 con->sock = newsock;
 479                 write_unlock_bh(&newsk->sk_callback_lock);
 480
 481                 /* Wake up receive process in case of 'SYN+' message */
 482                 newsk->sk_data_ready(newsk);
 483         }
 484 }
 485
 486 /* tipc_toprsv_listener_data_ready - interrupt callback with connection request
 487  * The queued job is launched into tipc_topsrv_accept()
 488  */
 489 static void tipc_topsrv_listener_data_ready(struct sock *sk)
 490 {
 491         struct tipc_topsrv *srv;
 492
 493         read_lock_bh(&sk->sk_callback_lock);
 494         srv = sk->sk_user_data;
 495         if (srv->listener)
 496                 queue_work(srv->rcv_wq, &srv->awork);
 497         read_unlock_bh(&sk->sk_callback_lock);
 498 }
 499
 500 static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
 501 {
 502         int imp = TIPC_CRITICAL_IMPORTANCE;
 503         struct socket *lsock = NULL;
 504         struct sockaddr_tipc saddr;
 505         struct sock *sk;
 506         int rc;
 507
 508         rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
 509         if (rc < 0)
 510                 return rc;
 511
 512         srv->listener = lsock;
 513         sk = lsock->sk;
 514         write_lock_bh(&sk->sk_callback_lock);
 515         sk->sk_data_ready = tipc_topsrv_listener_data_ready;
 516         sk->sk_user_data = srv;
 517         write_unlock_bh(&sk->sk_callback_lock);
 518
 519         rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
 520                                (char *)&imp, sizeof(imp));
 521         if (rc < 0)
 522                 goto err;
 523
 524         saddr.family                    = AF_TIPC;
 525         saddr.addrtype                  = TIPC_ADDR_NAMESEQ;
 526         saddr.addr.nameseq.type         = TIPC_TOP_SRV;
 527         saddr.addr.nameseq.lower        = TIPC_TOP_SRV;
 528         saddr.addr.nameseq.upper        = TIPC_TOP_SRV;
 529         saddr.scope                     = TIPC_NODE_SCOPE;
 530
 531         rc = kernel_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
 532         if (rc < 0)
 533                 goto err;
 534         rc = kernel_listen(lsock, 0);
 535         if (rc < 0)
 536                 goto err;
 537
 538         /* As server's listening socket owner and creator is the same module,
 539          * we have to decrease TIPC module reference count to guarantee that
 540          * it remains zero after the server socket is created, otherwise,
 541          * executing "rmmod" command is unable to make TIPC module deleted
 542          * after TIPC module is inserted successfully.
 543          *
 544          * However, the reference count is ever increased twice in
 545          * sock_create_kern(): one is to increase the reference count of owner
 546          * of TIPC socket's proto_ops struct; another is to increment the
 547          * reference count of owner of TIPC proto struct. Therefore, we must
 548          * decrement the module reference count twice to ensure that it keeps
 549          * zero after server's listening socket is created. Of course, we
 550          * must bump the module reference count twice as well before the socket
 551          * is closed.
 552          */
 553         module_put(lsock->ops->owner);
 554         module_put(sk->sk_prot_creator->owner);
 555
 556         return 0;
 557 err:
 558         sock_release(lsock);
 559         return -EINVAL;
 560 }
 561
 562 bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
 563                              u32 upper, u32 filter, int *conid)
 564 {
 565         struct tipc_subscr sub;
 566         struct tipc_conn *con;
 567         int rc;
 568
 569         sub.seq.type = type;
 570         sub.seq.lower = lower;
 571         sub.seq.upper = upper;
 572         sub.timeout = TIPC_WAIT_FOREVER;
 573         sub.filter = filter;
 574         *(u32 *)&sub.usr_handle = port;
 575
 576         con = tipc_conn_alloc(tipc_topsrv(net));
 577         if (IS_ERR(con))
 578                 return false;
 579
 580         *conid = con->conid;
 581         con->sock = NULL;
 582         rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
 583         if (rc >= 0)
 584                 return true;
 585         conn_put(con);
 586         return false;
 587 }
 588
 589 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
 590 {
 591         struct tipc_conn *con;
 592
 593         con = tipc_conn_lookup(tipc_topsrv(net), conid);
 594         if (!con)
 595                 return;
 596
 597         test_and_clear_bit(CF_CONNECTED, &con->flags);
 598         tipc_conn_delete_sub(con, NULL);
 599         conn_put(con);
 600         conn_put(con);
 601 }
 602
 603 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
 604 {
 605         u32 port = *(u32 *)&evt->s.usr_handle;
 606         u32 self = tipc_own_addr(net);
 607         struct sk_buff_head evtq;
 608         struct sk_buff *skb;
 609
 610         skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
 611                               self, self, port, port, 0);
 612         if (!skb)
 613                 return;
 614         msg_set_dest_droppable(buf_msg(skb), true);
 615         memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
 616         skb_queue_head_init(&evtq);
 617         __skb_queue_tail(&evtq, skb);
 618         tipc_sk_rcv(net, &evtq);
 619 }
 620
 621 static int tipc_topsrv_work_start(struct tipc_topsrv *s)
 622 {
 623         s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
 624         if (!s->rcv_wq) {
 625                 pr_err("can't start tipc receive workqueue\n");
 626                 return -ENOMEM;
 627         }
 628
 629         s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
 630         if (!s->send_wq) {
 631                 pr_err("can't start tipc send workqueue\n");
 632                 destroy_workqueue(s->rcv_wq);
 633                 return -ENOMEM;
 634         }
 635
 636         return 0;
 637 }
 638
 639 static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
 640 {
 641         destroy_workqueue(s->rcv_wq);
 642         destroy_workqueue(s->send_wq);
 643 }
 644
 645 int tipc_topsrv_start(struct net *net)
 646 {
 647         struct tipc_net *tn = tipc_net(net);
 648         const char name[] = "topology_server";
 649         struct tipc_topsrv *srv;
 650         int ret;
 651
 652         srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
 653         if (!srv)
 654                 return -ENOMEM;
 655
 656         srv->net = net;
 657         srv->max_rcvbuf_size = sizeof(struct tipc_subscr);
 658         INIT_WORK(&srv->awork, tipc_topsrv_accept);
 659
 660         strscpy(srv->name, name, sizeof(srv->name));
 661         tn->topsrv = srv;
 662         atomic_set(&tn->subscription_count, 0);
 663
 664         spin_lock_init(&srv->idr_lock);
 665         idr_init(&srv->conn_idr);
 666         srv->idr_in_use = 0;
 667
 668         ret = tipc_topsrv_work_start(srv);
 669         if (ret < 0)
 670                 return ret;
 671
 672         ret = tipc_topsrv_create_listener(srv);
 673         if (ret < 0)
 674                 tipc_topsrv_work_stop(srv);
 675
 676         return ret;
 677 }
 678
 679 void tipc_topsrv_stop(struct net *net)
 680 {
 681         struct tipc_topsrv *srv = tipc_topsrv(net);
 682         struct socket *lsock = srv->listener;
 683         struct tipc_conn *con;
 684         int id;
 685
 686         spin_lock_bh(&srv->idr_lock);
 687         for (id = 0; srv->idr_in_use; id++) {
 688                 con = idr_find(&srv->conn_idr, id);
 689                 if (con) {
 690                         spin_unlock_bh(&srv->idr_lock);
 691                         tipc_conn_close(con);
 692                         spin_lock_bh(&srv->idr_lock);
 693                 }
 694         }
 695         __module_get(lsock->ops->owner);
 696         __module_get(lsock->sk->sk_prot_creator->owner);
 697         srv->listener = NULL;
 698         spin_unlock_bh(&srv->idr_lock);
 699         sock_release(lsock);
 700         tipc_topsrv_work_stop(srv);
 701         idr_destroy(&srv->conn_idr);
 702         kfree(srv);
 703 }