net/tipc/server.c

   1 /*
   2  * net/tipc/server.c: TIPC server infrastructure
   3  *
   4  * Copyright (c) 2012-2013, Wind River Systems
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the names of the copyright holders nor the names of its
  16  *    contributors may be used to endorse or promote products derived from
  17  *    this software without specific prior written permission.
  18  *
  19  * Alternatively, this software may be distributed under the terms of the
  20  * GNU General Public License ("GPL") version 2 as published by the Free
  21  * Software Foundation.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  24  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  27  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  33  * POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #include "server.h"
  37 #include "core.h"
  38 #include <net/sock.h>
  39
  40 /* Number of messages to send before rescheduling */
  41 #define MAX_SEND_MSG_COUNT      25
  42 #define MAX_RECV_MSG_COUNT      25
  43 #define CF_CONNECTED            1
  44
  45 #define sock2con(x) ((struct tipc_conn *)(x)->sk_user_data)
  46
  47 /**
  48  * struct tipc_conn - TIPC connection structure
  49  * @kref: reference counter to connection object
  50  * @conid: connection identifier
  51  * @sock: socket handler associated with connection
  52  * @flags: indicates connection state
  53  * @server: pointer to connected server
  54  * @rwork: receive work item
  55  * @usr_data: user-specified field
  56  * @rx_action: what to do when connection socket is active
  57  * @outqueue: pointer to first outbound message in queue
  58  * @outqueue_lock: control access to the outqueue
  59  * @outqueue: list of connection objects for its server
  60  * @swork: send work item
  61  */
  62 struct tipc_conn {
  63         struct kref kref;
  64         int conid;
  65         struct socket *sock;
  66         unsigned long flags;
  67         struct tipc_server *server;
  68         struct work_struct rwork;
  69         int (*rx_action) (struct tipc_conn *con);
  70         void *usr_data;
  71         struct list_head outqueue;
  72         spinlock_t outqueue_lock;
  73         struct work_struct swork;
  74 };
  75
  76 /* An entry waiting to be sent */
  77 struct outqueue_entry {
  78         struct list_head list;
  79         struct kvec iov;
  80         struct sockaddr_tipc dest;
  81 };
  82
  83 static void tipc_recv_work(struct work_struct *work);
  84 static void tipc_send_work(struct work_struct *work);
  85 static void tipc_clean_outqueues(struct tipc_conn *con);
  86
  87 static void tipc_conn_kref_release(struct kref *kref)
  88 {
  89         struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
  90
  91         if (con->sock) {
  92                 tipc_sock_release_local(con->sock);
  93                 con->sock = NULL;
  94         }
  95
  96         tipc_clean_outqueues(con);
  97         kfree(con);
  98 }
  99
 100 static void conn_put(struct tipc_conn *con)
 101 {
 102         kref_put(&con->kref, tipc_conn_kref_release);
 103 }
 104
 105 static void conn_get(struct tipc_conn *con)
 106 {
 107         kref_get(&con->kref);
 108 }
 109
 110 static struct tipc_conn *tipc_conn_lookup(struct tipc_server *s, int conid)
 111 {
 112         struct tipc_conn *con;
 113
 114         spin_lock_bh(&s->idr_lock);
 115         con = idr_find(&s->conn_idr, conid);
 116         if (con)
 117                 conn_get(con);
 118         spin_unlock_bh(&s->idr_lock);
 119         return con;
 120 }
 121
 122 static void sock_data_ready(struct sock *sk)
 123 {
 124         struct tipc_conn *con;
 125
 126         read_lock(&sk->sk_callback_lock);
 127         con = sock2con(sk);
 128         if (con && test_bit(CF_CONNECTED, &con->flags)) {
 129                 conn_get(con);
 130                 if (!queue_work(con->server->rcv_wq, &con->rwork))
 131                         conn_put(con);
 132         }
 133         read_unlock(&sk->sk_callback_lock);
 134 }
 135
 136 static void sock_write_space(struct sock *sk)
 137 {
 138         struct tipc_conn *con;
 139
 140         read_lock(&sk->sk_callback_lock);
 141         con = sock2con(sk);
 142         if (con && test_bit(CF_CONNECTED, &con->flags)) {
 143                 conn_get(con);
 144                 if (!queue_work(con->server->send_wq, &con->swork))
 145                         conn_put(con);
 146         }
 147         read_unlock(&sk->sk_callback_lock);
 148 }
 149
 150 static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)
 151 {
 152         struct sock *sk = sock->sk;
 153
 154         write_lock_bh(&sk->sk_callback_lock);
 155
 156         sk->sk_data_ready = sock_data_ready;
 157         sk->sk_write_space = sock_write_space;
 158         sk->sk_user_data = con;
 159
 160         con->sock = sock;
 161
 162         write_unlock_bh(&sk->sk_callback_lock);
 163 }
 164
 165 static void tipc_unregister_callbacks(struct tipc_conn *con)
 166 {
 167         struct sock *sk = con->sock->sk;
 168
 169         write_lock_bh(&sk->sk_callback_lock);
 170         sk->sk_user_data = NULL;
 171         write_unlock_bh(&sk->sk_callback_lock);
 172 }
 173
 174 static void tipc_close_conn(struct tipc_conn *con)
 175 {
 176         struct tipc_server *s = con->server;
 177
 178         if (test_and_clear_bit(CF_CONNECTED, &con->flags)) {
 179                 if (con->conid)
 180                         s->tipc_conn_shutdown(con->conid, con->usr_data);
 181
 182                 spin_lock_bh(&s->idr_lock);
 183                 idr_remove(&s->conn_idr, con->conid);
 184                 s->idr_in_use--;
 185                 spin_unlock_bh(&s->idr_lock);
 186
 187                 tipc_unregister_callbacks(con);
 188
 189                 /* We shouldn't flush pending works as we may be in the
 190                  * thread. In fact the races with pending rx/tx work structs
 191                  * are harmless for us here as we have already deleted this
 192                  * connection from server connection list and set
 193                  * sk->sk_user_data to 0 before releasing connection object.
 194                  */
 195                 kernel_sock_shutdown(con->sock, SHUT_RDWR);
 196
 197                 conn_put(con);
 198         }
 199 }
 200
 201 static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
 202 {
 203         struct tipc_conn *con;
 204         int ret;
 205
 206         con = kzalloc(sizeof(struct tipc_conn), GFP_ATOMIC);
 207         if (!con)
 208                 return ERR_PTR(-ENOMEM);
 209
 210         kref_init(&con->kref);
 211         INIT_LIST_HEAD(&con->outqueue);
 212         spin_lock_init(&con->outqueue_lock);
 213         INIT_WORK(&con->swork, tipc_send_work);
 214         INIT_WORK(&con->rwork, tipc_recv_work);
 215
 216         spin_lock_bh(&s->idr_lock);
 217         ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
 218         if (ret < 0) {
 219                 kfree(con);
 220                 spin_unlock_bh(&s->idr_lock);
 221                 return ERR_PTR(-ENOMEM);
 222         }
 223         con->conid = ret;
 224         s->idr_in_use++;
 225         spin_unlock_bh(&s->idr_lock);
 226
 227         set_bit(CF_CONNECTED, &con->flags);
 228         con->server = s;
 229
 230         return con;
 231 }
 232
 233 static int tipc_receive_from_sock(struct tipc_conn *con)
 234 {
 235         struct msghdr msg = {};
 236         struct tipc_server *s = con->server;
 237         struct sockaddr_tipc addr;
 238         struct kvec iov;
 239         void *buf;
 240         int ret;
 241
 242         buf = kmem_cache_alloc(s->rcvbuf_cache, GFP_ATOMIC);
 243         if (!buf) {
 244                 ret = -ENOMEM;
 245                 goto out_close;
 246         }
 247
 248         iov.iov_base = buf;
 249         iov.iov_len = s->max_rcvbuf_size;
 250         msg.msg_name = &addr;
 251         ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
 252                              MSG_DONTWAIT);
 253         if (ret <= 0) {
 254                 kmem_cache_free(s->rcvbuf_cache, buf);
 255                 goto out_close;
 256         }
 257
 258         s->tipc_conn_recvmsg(con->conid, &addr, con->usr_data, buf, ret);
 259
 260         kmem_cache_free(s->rcvbuf_cache, buf);
 261
 262         return 0;
 263
 264 out_close:
 265         if (ret != -EWOULDBLOCK)
 266                 tipc_close_conn(con);
 267         else if (ret == 0)
 268                 /* Don't return success if we really got EOF */
 269                 ret = -EAGAIN;
 270
 271         return ret;
 272 }
 273
 274 static int tipc_accept_from_sock(struct tipc_conn *con)
 275 {
 276         struct tipc_server *s = con->server;
 277         struct socket *sock = con->sock;
 278         struct socket *newsock;
 279         struct tipc_conn *newcon;
 280         int ret;
 281
 282         ret = tipc_sock_accept_local(sock, &newsock, O_NONBLOCK);
 283         if (ret < 0)
 284                 return ret;
 285
 286         newcon = tipc_alloc_conn(con->server);
 287         if (IS_ERR(newcon)) {
 288                 ret = PTR_ERR(newcon);
 289                 sock_release(newsock);
 290                 return ret;
 291         }
 292
 293         newcon->rx_action = tipc_receive_from_sock;
 294         tipc_register_callbacks(newsock, newcon);
 295
 296         /* Notify that new connection is incoming */
 297         newcon->usr_data = s->tipc_conn_new(newcon->conid);
 298
 299         /* Wake up receive process in case of 'SYN+' message */
 300         newsock->sk->sk_data_ready(newsock->sk);
 301         return ret;
 302 }
 303
 304 static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
 305 {
 306         struct tipc_server *s = con->server;
 307         struct socket *sock = NULL;
 308         int ret;
 309
 310         ret = tipc_sock_create_local(s->type, &sock);
 311         if (ret < 0)
 312                 return NULL;
 313         ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE,
 314                                 (char *)&s->imp, sizeof(s->imp));
 315         if (ret < 0)
 316                 goto create_err;
 317         ret = kernel_bind(sock, (struct sockaddr *)s->saddr, sizeof(*s->saddr));
 318         if (ret < 0)
 319                 goto create_err;
 320
 321         switch (s->type) {
 322         case SOCK_STREAM:
 323         case SOCK_SEQPACKET:
 324                 con->rx_action = tipc_accept_from_sock;
 325
 326                 ret = kernel_listen(sock, 0);
 327                 if (ret < 0)
 328                         goto create_err;
 329                 break;
 330         case SOCK_DGRAM:
 331         case SOCK_RDM:
 332                 con->rx_action = tipc_receive_from_sock;
 333                 break;
 334         default:
 335                 pr_err("Unknown socket type %d\n", s->type);
 336                 goto create_err;
 337         }
 338         return sock;
 339
 340 create_err:
 341         sock_release(sock);
 342         con->sock = NULL;
 343         return NULL;
 344 }
 345
 346 static int tipc_open_listening_sock(struct tipc_server *s)
 347 {
 348         struct socket *sock;
 349         struct tipc_conn *con;
 350
 351         con = tipc_alloc_conn(s);
 352         if (IS_ERR(con))
 353                 return PTR_ERR(con);
 354
 355         sock = tipc_create_listen_sock(con);
 356         if (!sock) {
 357                 idr_remove(&s->conn_idr, con->conid);
 358                 s->idr_in_use--;
 359                 kfree(con);
 360                 return -EINVAL;
 361         }
 362
 363         tipc_register_callbacks(sock, con);
 364         return 0;
 365 }
 366
 367 static struct outqueue_entry *tipc_alloc_entry(void *data, int len)
 368 {
 369         struct outqueue_entry *entry;
 370         void *buf;
 371
 372         entry = kmalloc(sizeof(struct outqueue_entry), GFP_ATOMIC);
 373         if (!entry)
 374                 return NULL;
 375
 376         buf = kmalloc(len, GFP_ATOMIC);
 377         if (!buf) {
 378                 kfree(entry);
 379                 return NULL;
 380         }
 381
 382         memcpy(buf, data, len);
 383         entry->iov.iov_base = buf;
 384         entry->iov.iov_len = len;
 385
 386         return entry;
 387 }
 388
 389 static void tipc_free_entry(struct outqueue_entry *e)
 390 {
 391         kfree(e->iov.iov_base);
 392         kfree(e);
 393 }
 394
 395 static void tipc_clean_outqueues(struct tipc_conn *con)
 396 {
 397         struct outqueue_entry *e, *safe;
 398
 399         spin_lock_bh(&con->outqueue_lock);
 400         list_for_each_entry_safe(e, safe, &con->outqueue, list) {
 401                 list_del(&e->list);
 402                 tipc_free_entry(e);
 403         }
 404         spin_unlock_bh(&con->outqueue_lock);
 405 }
 406
 407 int tipc_conn_sendmsg(struct tipc_server *s, int conid,
 408                       struct sockaddr_tipc *addr, void *data, size_t len)
 409 {
 410         struct outqueue_entry *e;
 411         struct tipc_conn *con;
 412
 413         con = tipc_conn_lookup(s, conid);
 414         if (!con)
 415                 return -EINVAL;
 416
 417         e = tipc_alloc_entry(data, len);
 418         if (!e) {
 419                 conn_put(con);
 420                 return -ENOMEM;
 421         }
 422
 423         if (addr)
 424                 memcpy(&e->dest, addr, sizeof(struct sockaddr_tipc));
 425
 426         spin_lock_bh(&con->outqueue_lock);
 427         list_add_tail(&e->list, &con->outqueue);
 428         spin_unlock_bh(&con->outqueue_lock);
 429
 430         if (test_bit(CF_CONNECTED, &con->flags)) {
 431                 if (!queue_work(s->send_wq, &con->swork))
 432                         conn_put(con);
 433         } else {
 434                 conn_put(con);
 435         }
 436         return 0;
 437 }
 438
 439 void tipc_conn_terminate(struct tipc_server *s, int conid)
 440 {
 441         struct tipc_conn *con;
 442
 443         con = tipc_conn_lookup(s, conid);
 444         if (con) {
 445                 tipc_close_conn(con);
 446                 conn_put(con);
 447         }
 448 }
 449
 450 static void tipc_send_to_sock(struct tipc_conn *con)
 451 {
 452         int count = 0;
 453         struct tipc_server *s = con->server;
 454         struct outqueue_entry *e;
 455         struct msghdr msg;
 456         int ret;
 457
 458         spin_lock_bh(&con->outqueue_lock);
 459         while (1) {
 460                 e = list_entry(con->outqueue.next, struct outqueue_entry,
 461                                list);
 462                 if ((struct list_head *) e == &con->outqueue)
 463                         break;
 464                 spin_unlock_bh(&con->outqueue_lock);
 465
 466                 memset(&msg, 0, sizeof(msg));
 467                 msg.msg_flags = MSG_DONTWAIT;
 468
 469                 if (s->type == SOCK_DGRAM || s->type == SOCK_RDM) {
 470                         msg.msg_name = &e->dest;
 471                         msg.msg_namelen = sizeof(struct sockaddr_tipc);
 472                 }
 473                 ret = kernel_sendmsg(con->sock, &msg, &e->iov, 1,
 474                                      e->iov.iov_len);
 475                 if (ret == -EWOULDBLOCK || ret == 0) {
 476                         cond_resched();
 477                         goto out;
 478                 } else if (ret < 0) {
 479                         goto send_err;
 480                 }
 481
 482                 /* Don't starve users filling buffers */
 483                 if (++count >= MAX_SEND_MSG_COUNT) {
 484                         cond_resched();
 485                         count = 0;
 486                 }
 487
 488                 spin_lock_bh(&con->outqueue_lock);
 489                 list_del(&e->list);
 490                 tipc_free_entry(e);
 491         }
 492         spin_unlock_bh(&con->outqueue_lock);
 493 out:
 494         return;
 495
 496 send_err:
 497         tipc_close_conn(con);
 498 }
 499
 500 static void tipc_recv_work(struct work_struct *work)
 501 {
 502         struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
 503         int count = 0;
 504
 505         while (test_bit(CF_CONNECTED, &con->flags)) {
 506                 if (con->rx_action(con))
 507                         break;
 508
 509                 /* Don't flood Rx machine */
 510                 if (++count >= MAX_RECV_MSG_COUNT) {
 511                         cond_resched();
 512                         count = 0;
 513                 }
 514         }
 515         conn_put(con);
 516 }
 517
 518 static void tipc_send_work(struct work_struct *work)
 519 {
 520         struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
 521
 522         if (test_bit(CF_CONNECTED, &con->flags))
 523                 tipc_send_to_sock(con);
 524
 525         conn_put(con);
 526 }
 527
 528 static void tipc_work_stop(struct tipc_server *s)
 529 {
 530         destroy_workqueue(s->rcv_wq);
 531         destroy_workqueue(s->send_wq);
 532 }
 533
 534 static int tipc_work_start(struct tipc_server *s)
 535 {
 536         s->rcv_wq = alloc_workqueue("tipc_rcv", WQ_UNBOUND, 1);
 537         if (!s->rcv_wq) {
 538                 pr_err("can't start tipc receive workqueue\n");
 539                 return -ENOMEM;
 540         }
 541
 542         s->send_wq = alloc_workqueue("tipc_send", WQ_UNBOUND, 1);
 543         if (!s->send_wq) {
 544                 pr_err("can't start tipc send workqueue\n");
 545                 destroy_workqueue(s->rcv_wq);
 546                 return -ENOMEM;
 547         }
 548
 549         return 0;
 550 }
 551
 552 int tipc_server_start(struct tipc_server *s)
 553 {
 554         int ret;
 555
 556         spin_lock_init(&s->idr_lock);
 557         idr_init(&s->conn_idr);
 558         s->idr_in_use = 0;
 559
 560         s->rcvbuf_cache = kmem_cache_create(s->name, s->max_rcvbuf_size,
 561                                             0, SLAB_HWCACHE_ALIGN, NULL);
 562         if (!s->rcvbuf_cache)
 563                 return -ENOMEM;
 564
 565         ret = tipc_work_start(s);
 566         if (ret < 0) {
 567                 kmem_cache_destroy(s->rcvbuf_cache);
 568                 return ret;
 569         }
 570         ret = tipc_open_listening_sock(s);
 571         if (ret < 0) {
 572                 tipc_work_stop(s);
 573                 kmem_cache_destroy(s->rcvbuf_cache);
 574                 return ret;
 575         }
 576         return ret;
 577 }
 578
 579 void tipc_server_stop(struct tipc_server *s)
 580 {
 581         struct tipc_conn *con;
 582         int total = 0;
 583         int id;
 584
 585         spin_lock_bh(&s->idr_lock);
 586         for (id = 0; total < s->idr_in_use; id++) {
 587                 con = idr_find(&s->conn_idr, id);
 588                 if (con) {
 589                         total++;
 590                         spin_unlock_bh(&s->idr_lock);
 591                         tipc_close_conn(con);
 592                         spin_lock_bh(&s->idr_lock);
 593                 }
 594         }
 595         spin_unlock_bh(&s->idr_lock);
 596
 597         tipc_work_stop(s);
 598         kmem_cache_destroy(s->rcvbuf_cache);
 599         idr_destroy(&s->conn_idr);
 600 }