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         struct tipc_server *s = con->server;
  91
  92         if (con->sock) {
  93                 tipc_sock_release_local(con->sock);
  94                 con->sock = NULL;
  95         }
  96
  97         tipc_clean_outqueues(con);
  98
  99         if (con->conid)
 100                 s->tipc_conn_shutdown(con->conid, con->usr_data);
 101
 102         kfree(con);
 103 }
 104
 105 static void conn_put(struct tipc_conn *con)
 106 {
 107         kref_put(&con->kref, tipc_conn_kref_release);
 108 }
 109
 110 static void conn_get(struct tipc_conn *con)
 111 {
 112         kref_get(&con->kref);
 113 }
 114
 115 static struct tipc_conn *tipc_conn_lookup(struct tipc_server *s, int conid)
 116 {
 117         struct tipc_conn *con;
 118
 119         spin_lock_bh(&s->idr_lock);
 120         con = idr_find(&s->conn_idr, conid);
 121         if (con)
 122                 conn_get(con);
 123         spin_unlock_bh(&s->idr_lock);
 124         return con;
 125 }
 126
 127 static void sock_data_ready(struct sock *sk, int unused)
 128 {
 129         struct tipc_conn *con;
 130
 131         read_lock(&sk->sk_callback_lock);
 132         con = sock2con(sk);
 133         if (con && test_bit(CF_CONNECTED, &con->flags)) {
 134                 conn_get(con);
 135                 if (!queue_work(con->server->rcv_wq, &con->rwork))
 136                         conn_put(con);
 137         }
 138         read_unlock(&sk->sk_callback_lock);
 139 }
 140
 141 static void sock_write_space(struct sock *sk)
 142 {
 143         struct tipc_conn *con;
 144
 145         read_lock(&sk->sk_callback_lock);
 146         con = sock2con(sk);
 147         if (con && test_bit(CF_CONNECTED, &con->flags)) {
 148                 conn_get(con);
 149                 if (!queue_work(con->server->send_wq, &con->swork))
 150                         conn_put(con);
 151         }
 152         read_unlock(&sk->sk_callback_lock);
 153 }
 154
 155 static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)
 156 {
 157         struct sock *sk = sock->sk;
 158
 159         write_lock_bh(&sk->sk_callback_lock);
 160
 161         sk->sk_data_ready = sock_data_ready;
 162         sk->sk_write_space = sock_write_space;
 163         sk->sk_user_data = con;
 164
 165         con->sock = sock;
 166
 167         write_unlock_bh(&sk->sk_callback_lock);
 168 }
 169
 170 static void tipc_unregister_callbacks(struct tipc_conn *con)
 171 {
 172         struct sock *sk = con->sock->sk;
 173
 174         write_lock_bh(&sk->sk_callback_lock);
 175         sk->sk_user_data = NULL;
 176         write_unlock_bh(&sk->sk_callback_lock);
 177 }
 178
 179 static void tipc_close_conn(struct tipc_conn *con)
 180 {
 181         struct tipc_server *s = con->server;
 182
 183         if (test_and_clear_bit(CF_CONNECTED, &con->flags)) {
 184                 spin_lock_bh(&s->idr_lock);
 185                 idr_remove(&s->conn_idr, con->conid);
 186                 s->idr_in_use--;
 187                 spin_unlock_bh(&s->idr_lock);
 188
 189                 tipc_unregister_callbacks(con);
 190
 191                 /* We shouldn't flush pending works as we may be in the
 192                  * thread. In fact the races with pending rx/tx work structs
 193                  * are harmless for us here as we have already deleted this
 194                  * connection from server connection list and set
 195                  * sk->sk_user_data to 0 before releasing connection object.
 196                  */
 197                 kernel_sock_shutdown(con->sock, SHUT_RDWR);
 198
 199                 conn_put(con);
 200         }
 201 }
 202
 203 static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
 204 {
 205         struct tipc_conn *con;
 206         int ret;
 207
 208         con = kzalloc(sizeof(struct tipc_conn), GFP_ATOMIC);
 209         if (!con)
 210                 return ERR_PTR(-ENOMEM);
 211
 212         kref_init(&con->kref);
 213         INIT_LIST_HEAD(&con->outqueue);
 214         spin_lock_init(&con->outqueue_lock);
 215         INIT_WORK(&con->swork, tipc_send_work);
 216         INIT_WORK(&con->rwork, tipc_recv_work);
 217
 218         spin_lock_bh(&s->idr_lock);
 219         ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
 220         if (ret < 0) {
 221                 kfree(con);
 222                 spin_unlock_bh(&s->idr_lock);
 223                 return ERR_PTR(-ENOMEM);
 224         }
 225         con->conid = ret;
 226         s->idr_in_use++;
 227         spin_unlock_bh(&s->idr_lock);
 228
 229         set_bit(CF_CONNECTED, &con->flags);
 230         con->server = s;
 231
 232         return con;
 233 }
 234
 235 static int tipc_receive_from_sock(struct tipc_conn *con)
 236 {
 237         struct msghdr msg = {};
 238         struct tipc_server *s = con->server;
 239         struct sockaddr_tipc addr;
 240         struct kvec iov;
 241         void *buf;
 242         int ret;
 243
 244         buf = kmem_cache_alloc(s->rcvbuf_cache, GFP_ATOMIC);
 245         if (!buf) {
 246                 ret = -ENOMEM;
 247                 goto out_close;
 248         }
 249
 250         iov.iov_base = buf;
 251         iov.iov_len = s->max_rcvbuf_size;
 252         msg.msg_name = &addr;
 253         ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
 254                              MSG_DONTWAIT);
 255         if (ret <= 0) {
 256                 kmem_cache_free(s->rcvbuf_cache, buf);
 257                 goto out_close;
 258         }
 259
 260         s->tipc_conn_recvmsg(con->conid, &addr, con->usr_data, buf, ret);
 261
 262         kmem_cache_free(s->rcvbuf_cache, buf);
 263
 264         return 0;
 265
 266 out_close:
 267         if (ret != -EWOULDBLOCK)
 268                 tipc_close_conn(con);
 269         else if (ret == 0)
 270                 /* Don't return success if we really got EOF */
 271                 ret = -EAGAIN;
 272
 273         return ret;
 274 }
 275
 276 static int tipc_accept_from_sock(struct tipc_conn *con)
 277 {
 278         struct tipc_server *s = con->server;
 279         struct socket *sock = con->sock;
 280         struct socket *newsock;
 281         struct tipc_conn *newcon;
 282         int ret;
 283
 284         ret = tipc_sock_accept_local(sock, &newsock, O_NONBLOCK);
 285         if (ret < 0)
 286                 return ret;
 287
 288         newcon = tipc_alloc_conn(con->server);
 289         if (IS_ERR(newcon)) {
 290                 ret = PTR_ERR(newcon);
 291                 sock_release(newsock);
 292                 return ret;
 293         }
 294
 295         newcon->rx_action = tipc_receive_from_sock;
 296         tipc_register_callbacks(newsock, newcon);
 297
 298         /* Notify that new connection is incoming */
 299         newcon->usr_data = s->tipc_conn_new(newcon->conid);
 300
 301         /* Wake up receive process in case of 'SYN+' message */
 302         newsock->sk->sk_data_ready(newsock->sk, 0);
 303         return ret;
 304 }
 305
 306 static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
 307 {
 308         struct tipc_server *s = con->server;
 309         struct socket *sock = NULL;
 310         int ret;
 311
 312         ret = tipc_sock_create_local(s->type, &sock);
 313         if (ret < 0)
 314                 return NULL;
 315         ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE,
 316                                 (char *)&s->imp, sizeof(s->imp));
 317         if (ret < 0)
 318                 goto create_err;
 319         ret = kernel_bind(sock, (struct sockaddr *)s->saddr, sizeof(*s->saddr));
 320         if (ret < 0)
 321                 goto create_err;
 322
 323         switch (s->type) {
 324         case SOCK_STREAM:
 325         case SOCK_SEQPACKET:
 326                 con->rx_action = tipc_accept_from_sock;
 327
 328                 ret = kernel_listen(sock, 0);
 329                 if (ret < 0)
 330                         goto create_err;
 331                 break;
 332         case SOCK_DGRAM:
 333         case SOCK_RDM:
 334                 con->rx_action = tipc_receive_from_sock;
 335                 break;
 336         default:
 337                 pr_err("Unknown socket type %d\n", s->type);
 338                 goto create_err;
 339         }
 340         return sock;
 341
 342 create_err:
 343         sock_release(sock);
 344         con->sock = NULL;
 345         return NULL;
 346 }
 347
 348 static int tipc_open_listening_sock(struct tipc_server *s)
 349 {
 350         struct socket *sock;
 351         struct tipc_conn *con;
 352
 353         con = tipc_alloc_conn(s);
 354         if (IS_ERR(con))
 355                 return PTR_ERR(con);
 356
 357         sock = tipc_create_listen_sock(con);
 358         if (!sock) {
 359                 idr_remove(&s->conn_idr, con->conid);
 360                 s->idr_in_use--;
 361                 kfree(con);
 362                 return -EINVAL;
 363         }
 364
 365         tipc_register_callbacks(sock, con);
 366         return 0;
 367 }
 368
 369 static struct outqueue_entry *tipc_alloc_entry(void *data, int len)
 370 {
 371         struct outqueue_entry *entry;
 372         void *buf;
 373
 374         entry = kmalloc(sizeof(struct outqueue_entry), GFP_ATOMIC);
 375         if (!entry)
 376                 return NULL;
 377
 378         buf = kmalloc(len, GFP_ATOMIC);
 379         if (!buf) {
 380                 kfree(entry);
 381                 return NULL;
 382         }
 383
 384         memcpy(buf, data, len);
 385         entry->iov.iov_base = buf;
 386         entry->iov.iov_len = len;
 387
 388         return entry;
 389 }
 390
 391 static void tipc_free_entry(struct outqueue_entry *e)
 392 {
 393         kfree(e->iov.iov_base);
 394         kfree(e);
 395 }
 396
 397 static void tipc_clean_outqueues(struct tipc_conn *con)
 398 {
 399         struct outqueue_entry *e, *safe;
 400
 401         spin_lock_bh(&con->outqueue_lock);
 402         list_for_each_entry_safe(e, safe, &con->outqueue, list) {
 403                 list_del(&e->list);
 404                 tipc_free_entry(e);
 405         }
 406         spin_unlock_bh(&con->outqueue_lock);
 407 }
 408
 409 int tipc_conn_sendmsg(struct tipc_server *s, int conid,
 410                       struct sockaddr_tipc *addr, void *data, size_t len)
 411 {
 412         struct outqueue_entry *e;
 413         struct tipc_conn *con;
 414
 415         con = tipc_conn_lookup(s, conid);
 416         if (!con)
 417                 return -EINVAL;
 418
 419         e = tipc_alloc_entry(data, len);
 420         if (!e) {
 421                 conn_put(con);
 422                 return -ENOMEM;
 423         }
 424
 425         if (addr)
 426                 memcpy(&e->dest, addr, sizeof(struct sockaddr_tipc));
 427
 428         spin_lock_bh(&con->outqueue_lock);
 429         list_add_tail(&e->list, &con->outqueue);
 430         spin_unlock_bh(&con->outqueue_lock);
 431
 432         if (test_bit(CF_CONNECTED, &con->flags))
 433                 if (!queue_work(s->send_wq, &con->swork))
 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         s->enabled = 1;
 577         return ret;
 578 }
 579
 580 void tipc_server_stop(struct tipc_server *s)
 581 {
 582         struct tipc_conn *con;
 583         int total = 0;
 584         int id;
 585
 586         if (!s->enabled)
 587                 return;
 588
 589         s->enabled = 0;
 590         spin_lock_bh(&s->idr_lock);
 591         for (id = 0; total < s->idr_in_use; id++) {
 592                 con = idr_find(&s->conn_idr, id);
 593                 if (con) {
 594                         total++;
 595                         spin_unlock_bh(&s->idr_lock);
 596                         tipc_close_conn(con);
 597                         spin_lock_bh(&s->idr_lock);
 598                 }
 599         }
 600         spin_unlock_bh(&s->idr_lock);
 601
 602         tipc_work_stop(s);
 603         kmem_cache_destroy(s->rcvbuf_cache);
 604         idr_destroy(&s->conn_idr);
 605 }