net/phonet/socket.c

   1 /*
   2  * File: socket.c
   3  *
   4  * Phonet sockets
   5  *
   6  * Copyright (C) 2008 Nokia Corporation.
   7  *
   8  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
   9  *          Rémi Denis-Courmont
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * version 2 as published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  23  * 02110-1301 USA
  24  */
  25
  26 #include <linux/gfp.h>
  27 #include <linux/kernel.h>
  28 #include <linux/net.h>
  29 #include <linux/poll.h>
  30 #include <net/sock.h>
  31 #include <net/tcp_states.h>
  32
  33 #include <linux/phonet.h>
  34 #include <linux/export.h>
  35 #include <net/phonet/phonet.h>
  36 #include <net/phonet/pep.h>
  37 #include <net/phonet/pn_dev.h>
  38
  39 static int pn_socket_release(struct socket *sock)
  40 {
  41         struct sock *sk = sock->sk;
  42
  43         if (sk) {
  44                 sock->sk = NULL;
  45                 sk->sk_prot->close(sk, 0);
  46         }
  47         return 0;
  48 }
  49
  50 #define PN_HASHSIZE     16
  51 #define PN_HASHMASK     (PN_HASHSIZE-1)
  52
  53
  54 static struct  {
  55         struct hlist_head hlist[PN_HASHSIZE];
  56         struct mutex lock;
  57 } pnsocks;
  58
  59 void __init pn_sock_init(void)
  60 {
  61         unsigned int i;
  62
  63         for (i = 0; i < PN_HASHSIZE; i++)
  64                 INIT_HLIST_HEAD(pnsocks.hlist + i);
  65         mutex_init(&pnsocks.lock);
  66 }
  67
  68 static struct hlist_head *pn_hash_list(u16 obj)
  69 {
  70         return pnsocks.hlist + (obj & PN_HASHMASK);
  71 }
  72
  73 /*
  74  * Find address based on socket address, match only certain fields.
  75  * Also grab sock if it was found. Remember to sock_put it later.
  76  */
  77 struct sock *pn_find_sock_by_sa(struct net *net, const struct sockaddr_pn *spn)
  78 {
  79         struct sock *sknode;
  80         struct sock *rval = NULL;
  81         u16 obj = pn_sockaddr_get_object(spn);
  82         u8 res = spn->spn_resource;
  83         struct hlist_head *hlist = pn_hash_list(obj);
  84
  85         rcu_read_lock();
  86         sk_for_each_rcu(sknode, hlist) {
  87                 struct pn_sock *pn = pn_sk(sknode);
  88                 BUG_ON(!pn->sobject); /* unbound socket */
  89
  90                 if (!net_eq(sock_net(sknode), net))
  91                         continue;
  92                 if (pn_port(obj)) {
  93                         /* Look up socket by port */
  94                         if (pn_port(pn->sobject) != pn_port(obj))
  95                                 continue;
  96                 } else {
  97                         /* If port is zero, look up by resource */
  98                         if (pn->resource != res)
  99                                 continue;
 100                 }
 101                 if (pn_addr(pn->sobject) &&
 102                     pn_addr(pn->sobject) != pn_addr(obj))
 103                         continue;
 104
 105                 rval = sknode;
 106                 sock_hold(sknode);
 107                 break;
 108         }
 109         rcu_read_unlock();
 110
 111         return rval;
 112 }
 113
 114 /* Deliver a broadcast packet (only in bottom-half) */
 115 void pn_deliver_sock_broadcast(struct net *net, struct sk_buff *skb)
 116 {
 117         struct hlist_head *hlist = pnsocks.hlist;
 118         unsigned int h;
 119
 120         rcu_read_lock();
 121         for (h = 0; h < PN_HASHSIZE; h++) {
 122                 struct sock *sknode;
 123
 124                 sk_for_each(sknode, hlist) {
 125                         struct sk_buff *clone;
 126
 127                         if (!net_eq(sock_net(sknode), net))
 128                                 continue;
 129                         if (!sock_flag(sknode, SOCK_BROADCAST))
 130                                 continue;
 131
 132                         clone = skb_clone(skb, GFP_ATOMIC);
 133                         if (clone) {
 134                                 sock_hold(sknode);
 135                                 sk_receive_skb(sknode, clone, 0);
 136                         }
 137                 }
 138                 hlist++;
 139         }
 140         rcu_read_unlock();
 141 }
 142
 143 int pn_sock_hash(struct sock *sk)
 144 {
 145         struct hlist_head *hlist = pn_hash_list(pn_sk(sk)->sobject);
 146
 147         mutex_lock(&pnsocks.lock);
 148         sk_add_node_rcu(sk, hlist);
 149         mutex_unlock(&pnsocks.lock);
 150
 151         return 0;
 152 }
 153 EXPORT_SYMBOL(pn_sock_hash);
 154
 155 void pn_sock_unhash(struct sock *sk)
 156 {
 157         mutex_lock(&pnsocks.lock);
 158         sk_del_node_init_rcu(sk);
 159         mutex_unlock(&pnsocks.lock);
 160         pn_sock_unbind_all_res(sk);
 161         synchronize_rcu();
 162 }
 163 EXPORT_SYMBOL(pn_sock_unhash);
 164
 165 static DEFINE_MUTEX(port_mutex);
 166
 167 static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
 168 {
 169         struct sock *sk = sock->sk;
 170         struct pn_sock *pn = pn_sk(sk);
 171         struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
 172         int err;
 173         u16 handle;
 174         u8 saddr;
 175
 176         if (sk->sk_prot->bind)
 177                 return sk->sk_prot->bind(sk, addr, len);
 178
 179         if (len < sizeof(struct sockaddr_pn))
 180                 return -EINVAL;
 181         if (spn->spn_family != AF_PHONET)
 182                 return -EAFNOSUPPORT;
 183
 184         handle = pn_sockaddr_get_object((struct sockaddr_pn *)addr);
 185         saddr = pn_addr(handle);
 186         if (saddr && phonet_address_lookup(sock_net(sk), saddr))
 187                 return -EADDRNOTAVAIL;
 188
 189         lock_sock(sk);
 190         if (sk->sk_state != TCP_CLOSE || pn_port(pn->sobject)) {
 191                 err = -EINVAL; /* attempt to rebind */
 192                 goto out;
 193         }
 194         WARN_ON(sk_hashed(sk));
 195         mutex_lock(&port_mutex);
 196         err = sk->sk_prot->get_port(sk, pn_port(handle));
 197         if (err)
 198                 goto out_port;
 199
 200         /* get_port() sets the port, bind() sets the address if applicable */
 201         pn->sobject = pn_object(saddr, pn_port(pn->sobject));
 202         pn->resource = spn->spn_resource;
 203
 204         /* Enable RX on the socket */
 205         err = sk->sk_prot->hash(sk);
 206 out_port:
 207         mutex_unlock(&port_mutex);
 208 out:
 209         release_sock(sk);
 210         return err;
 211 }
 212
 213 static int pn_socket_autobind(struct socket *sock)
 214 {
 215         struct sockaddr_pn sa;
 216         int err;
 217
 218         memset(&sa, 0, sizeof(sa));
 219         sa.spn_family = AF_PHONET;
 220         err = pn_socket_bind(sock, (struct sockaddr *)&sa,
 221                                 sizeof(struct sockaddr_pn));
 222         if (err != -EINVAL)
 223                 return err;
 224         BUG_ON(!pn_port(pn_sk(sock->sk)->sobject));
 225         return 0; /* socket was already bound */
 226 }
 227
 228 static int pn_socket_connect(struct socket *sock, struct sockaddr *addr,
 229                 int len, int flags)
 230 {
 231         struct sock *sk = sock->sk;
 232         struct pn_sock *pn = pn_sk(sk);
 233         struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
 234         struct task_struct *tsk = current;
 235         long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
 236         int err;
 237
 238         if (pn_socket_autobind(sock))
 239                 return -ENOBUFS;
 240         if (len < sizeof(struct sockaddr_pn))
 241                 return -EINVAL;
 242         if (spn->spn_family != AF_PHONET)
 243                 return -EAFNOSUPPORT;
 244
 245         lock_sock(sk);
 246
 247         switch (sock->state) {
 248         case SS_UNCONNECTED:
 249                 if (sk->sk_state != TCP_CLOSE) {
 250                         err = -EISCONN;
 251                         goto out;
 252                 }
 253                 break;
 254         case SS_CONNECTING:
 255                 err = -EALREADY;
 256                 goto out;
 257         default:
 258                 err = -EISCONN;
 259                 goto out;
 260         }
 261
 262         pn->dobject = pn_sockaddr_get_object(spn);
 263         pn->resource = pn_sockaddr_get_resource(spn);
 264         sock->state = SS_CONNECTING;
 265
 266         err = sk->sk_prot->connect(sk, addr, len);
 267         if (err) {
 268                 sock->state = SS_UNCONNECTED;
 269                 pn->dobject = 0;
 270                 goto out;
 271         }
 272
 273         while (sk->sk_state == TCP_SYN_SENT) {
 274                 DEFINE_WAIT(wait);
 275
 276                 if (!timeo) {
 277                         err = -EINPROGRESS;
 278                         goto out;
 279                 }
 280                 if (signal_pending(tsk)) {
 281                         err = sock_intr_errno(timeo);
 282                         goto out;
 283                 }
 284
 285                 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
 286                                                 TASK_INTERRUPTIBLE);
 287                 release_sock(sk);
 288                 timeo = schedule_timeout(timeo);
 289                 lock_sock(sk);
 290                 finish_wait(sk_sleep(sk), &wait);
 291         }
 292
 293         if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED))
 294                 err = 0;
 295         else if (sk->sk_state == TCP_CLOSE_WAIT)
 296                 err = -ECONNRESET;
 297         else
 298                 err = -ECONNREFUSED;
 299         sock->state = err ? SS_UNCONNECTED : SS_CONNECTED;
 300 out:
 301         release_sock(sk);
 302         return err;
 303 }
 304
 305 static int pn_socket_accept(struct socket *sock, struct socket *newsock,
 306                                 int flags)
 307 {
 308         struct sock *sk = sock->sk;
 309         struct sock *newsk;
 310         int err;
 311
 312         if (unlikely(sk->sk_state != TCP_LISTEN))
 313                 return -EINVAL;
 314
 315         newsk = sk->sk_prot->accept(sk, flags, &err);
 316         if (!newsk)
 317                 return err;
 318
 319         lock_sock(newsk);
 320         sock_graft(newsk, newsock);
 321         newsock->state = SS_CONNECTED;
 322         release_sock(newsk);
 323         return 0;
 324 }
 325
 326 static int pn_socket_getname(struct socket *sock, struct sockaddr *addr,
 327                                 int *sockaddr_len, int peer)
 328 {
 329         struct sock *sk = sock->sk;
 330         struct pn_sock *pn = pn_sk(sk);
 331
 332         memset(addr, 0, sizeof(struct sockaddr_pn));
 333         addr->sa_family = AF_PHONET;
 334         if (!peer) /* Race with bind() here is userland's problem. */
 335                 pn_sockaddr_set_object((struct sockaddr_pn *)addr,
 336                                         pn->sobject);
 337
 338         *sockaddr_len = sizeof(struct sockaddr_pn);
 339         return 0;
 340 }
 341
 342 static unsigned int pn_socket_poll(struct file *file, struct socket *sock,
 343                                         poll_table *wait)
 344 {
 345         struct sock *sk = sock->sk;
 346         struct pep_sock *pn = pep_sk(sk);
 347         unsigned int mask = 0;
 348
 349         poll_wait(file, sk_sleep(sk), wait);
 350
 351         if (sk->sk_state == TCP_CLOSE)
 352                 return POLLERR;
 353         if (!skb_queue_empty(&sk->sk_receive_queue))
 354                 mask |= POLLIN | POLLRDNORM;
 355         if (!skb_queue_empty(&pn->ctrlreq_queue))
 356                 mask |= POLLPRI;
 357         if (!mask && sk->sk_state == TCP_CLOSE_WAIT)
 358                 return POLLHUP;
 359
 360         if (sk->sk_state == TCP_ESTABLISHED &&
 361                 atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf &&
 362                 atomic_read(&pn->tx_credits))
 363                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 364
 365         return mask;
 366 }
 367
 368 static int pn_socket_ioctl(struct socket *sock, unsigned int cmd,
 369                                 unsigned long arg)
 370 {
 371         struct sock *sk = sock->sk;
 372         struct pn_sock *pn = pn_sk(sk);
 373
 374         if (cmd == SIOCPNGETOBJECT) {
 375                 struct net_device *dev;
 376                 u16 handle;
 377                 u8 saddr;
 378
 379                 if (get_user(handle, (__u16 __user *)arg))
 380                         return -EFAULT;
 381
 382                 lock_sock(sk);
 383                 if (sk->sk_bound_dev_if)
 384                         dev = dev_get_by_index(sock_net(sk),
 385                                                 sk->sk_bound_dev_if);
 386                 else
 387                         dev = phonet_device_get(sock_net(sk));
 388                 if (dev && (dev->flags & IFF_UP))
 389                         saddr = phonet_address_get(dev, pn_addr(handle));
 390                 else
 391                         saddr = PN_NO_ADDR;
 392                 release_sock(sk);
 393
 394                 if (dev)
 395                         dev_put(dev);
 396                 if (saddr == PN_NO_ADDR)
 397                         return -EHOSTUNREACH;
 398
 399                 handle = pn_object(saddr, pn_port(pn->sobject));
 400                 return put_user(handle, (__u16 __user *)arg);
 401         }
 402
 403         return sk->sk_prot->ioctl(sk, cmd, arg);
 404 }
 405
 406 static int pn_socket_listen(struct socket *sock, int backlog)
 407 {
 408         struct sock *sk = sock->sk;
 409         int err = 0;
 410
 411         if (pn_socket_autobind(sock))
 412                 return -ENOBUFS;
 413
 414         lock_sock(sk);
 415         if (sock->state != SS_UNCONNECTED) {
 416                 err = -EINVAL;
 417                 goto out;
 418         }
 419
 420         if (sk->sk_state != TCP_LISTEN) {
 421                 sk->sk_state = TCP_LISTEN;
 422                 sk->sk_ack_backlog = 0;
 423         }
 424         sk->sk_max_ack_backlog = backlog;
 425 out:
 426         release_sock(sk);
 427         return err;
 428 }
 429
 430 static int pn_socket_sendmsg(struct socket *sock, struct msghdr *m,
 431                              size_t total_len)
 432 {
 433         struct sock *sk = sock->sk;
 434
 435         if (pn_socket_autobind(sock))
 436                 return -EAGAIN;
 437
 438         return sk->sk_prot->sendmsg(sk, m, total_len);
 439 }
 440
 441 const struct proto_ops phonet_dgram_ops = {
 442         .family         = AF_PHONET,
 443         .owner          = THIS_MODULE,
 444         .release        = pn_socket_release,
 445         .bind           = pn_socket_bind,
 446         .connect        = sock_no_connect,
 447         .socketpair     = sock_no_socketpair,
 448         .accept         = sock_no_accept,
 449         .getname        = pn_socket_getname,
 450         .poll           = datagram_poll,
 451         .ioctl          = pn_socket_ioctl,
 452         .listen         = sock_no_listen,
 453         .shutdown       = sock_no_shutdown,
 454         .setsockopt     = sock_no_setsockopt,
 455         .getsockopt     = sock_no_getsockopt,
 456 #ifdef CONFIG_COMPAT
 457         .compat_setsockopt = sock_no_setsockopt,
 458         .compat_getsockopt = sock_no_getsockopt,
 459 #endif
 460         .sendmsg        = pn_socket_sendmsg,
 461         .recvmsg        = sock_common_recvmsg,
 462         .mmap           = sock_no_mmap,
 463         .sendpage       = sock_no_sendpage,
 464 };
 465
 466 const struct proto_ops phonet_stream_ops = {
 467         .family         = AF_PHONET,
 468         .owner          = THIS_MODULE,
 469         .release        = pn_socket_release,
 470         .bind           = pn_socket_bind,
 471         .connect        = pn_socket_connect,
 472         .socketpair     = sock_no_socketpair,
 473         .accept         = pn_socket_accept,
 474         .getname        = pn_socket_getname,
 475         .poll           = pn_socket_poll,
 476         .ioctl          = pn_socket_ioctl,
 477         .listen         = pn_socket_listen,
 478         .shutdown       = sock_no_shutdown,
 479         .setsockopt     = sock_common_setsockopt,
 480         .getsockopt     = sock_common_getsockopt,
 481 #ifdef CONFIG_COMPAT
 482         .compat_setsockopt = compat_sock_common_setsockopt,
 483         .compat_getsockopt = compat_sock_common_getsockopt,
 484 #endif
 485         .sendmsg        = pn_socket_sendmsg,
 486         .recvmsg        = sock_common_recvmsg,
 487         .mmap           = sock_no_mmap,
 488         .sendpage       = sock_no_sendpage,
 489 };
 490 EXPORT_SYMBOL(phonet_stream_ops);
 491
 492 /* allocate port for a socket */
 493 int pn_sock_get_port(struct sock *sk, unsigned short sport)
 494 {
 495         static int port_cur;
 496         struct net *net = sock_net(sk);
 497         struct pn_sock *pn = pn_sk(sk);
 498         struct sockaddr_pn try_sa;
 499         struct sock *tmpsk;
 500
 501         memset(&try_sa, 0, sizeof(struct sockaddr_pn));
 502         try_sa.spn_family = AF_PHONET;
 503         WARN_ON(!mutex_is_locked(&port_mutex));
 504         if (!sport) {
 505                 /* search free port */
 506                 int port, pmin, pmax;
 507
 508                 phonet_get_local_port_range(&pmin, &pmax);
 509                 for (port = pmin; port <= pmax; port++) {
 510                         port_cur++;
 511                         if (port_cur < pmin || port_cur > pmax)
 512                                 port_cur = pmin;
 513
 514                         pn_sockaddr_set_port(&try_sa, port_cur);
 515                         tmpsk = pn_find_sock_by_sa(net, &try_sa);
 516                         if (tmpsk == NULL) {
 517                                 sport = port_cur;
 518                                 goto found;
 519                         } else
 520                                 sock_put(tmpsk);
 521                 }
 522         } else {
 523                 /* try to find specific port */
 524                 pn_sockaddr_set_port(&try_sa, sport);
 525                 tmpsk = pn_find_sock_by_sa(net, &try_sa);
 526                 if (tmpsk == NULL)
 527                         /* No sock there! We can use that port... */
 528                         goto found;
 529                 else
 530                         sock_put(tmpsk);
 531         }
 532         /* the port must be in use already */
 533         return -EADDRINUSE;
 534
 535 found:
 536         pn->sobject = pn_object(pn_addr(pn->sobject), sport);
 537         return 0;
 538 }
 539 EXPORT_SYMBOL(pn_sock_get_port);
 540
 541 #ifdef CONFIG_PROC_FS
 542 static struct sock *pn_sock_get_idx(struct seq_file *seq, loff_t pos)
 543 {
 544         struct net *net = seq_file_net(seq);
 545         struct hlist_head *hlist = pnsocks.hlist;
 546         struct sock *sknode;
 547         unsigned int h;
 548
 549         for (h = 0; h < PN_HASHSIZE; h++) {
 550                 sk_for_each_rcu(sknode, hlist) {
 551                         if (!net_eq(net, sock_net(sknode)))
 552                                 continue;
 553                         if (!pos)
 554                                 return sknode;
 555                         pos--;
 556                 }
 557                 hlist++;
 558         }
 559         return NULL;
 560 }
 561
 562 static struct sock *pn_sock_get_next(struct seq_file *seq, struct sock *sk)
 563 {
 564         struct net *net = seq_file_net(seq);
 565
 566         do
 567                 sk = sk_next(sk);
 568         while (sk && !net_eq(net, sock_net(sk)));
 569
 570         return sk;
 571 }
 572
 573 static void *pn_sock_seq_start(struct seq_file *seq, loff_t *pos)
 574         __acquires(rcu)
 575 {
 576         rcu_read_lock();
 577         return *pos ? pn_sock_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 578 }
 579
 580 static void *pn_sock_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 581 {
 582         struct sock *sk;
 583
 584         if (v == SEQ_START_TOKEN)
 585                 sk = pn_sock_get_idx(seq, 0);
 586         else
 587                 sk = pn_sock_get_next(seq, v);
 588         (*pos)++;
 589         return sk;
 590 }
 591
 592 static void pn_sock_seq_stop(struct seq_file *seq, void *v)
 593         __releases(rcu)
 594 {
 595         rcu_read_unlock();
 596 }
 597
 598 static int pn_sock_seq_show(struct seq_file *seq, void *v)
 599 {
 600         seq_setwidth(seq, 127);
 601         if (v == SEQ_START_TOKEN)
 602                 seq_puts(seq, "pt  loc  rem rs st tx_queue rx_queue "
 603                         "  uid inode ref pointer drops");
 604         else {
 605                 struct sock *sk = v;
 606                 struct pn_sock *pn = pn_sk(sk);
 607
 608                 seq_printf(seq, "%2d %04X:%04X:%02X %02X %08X:%08X %5d %lu "
 609                         "%d %pK %d",
 610                         sk->sk_protocol, pn->sobject, pn->dobject,
 611                         pn->resource, sk->sk_state,
 612                         sk_wmem_alloc_get(sk), sk_rmem_alloc_get(sk),
 613                         from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
 614                         sock_i_ino(sk),
 615                         atomic_read(&sk->sk_refcnt), sk,
 616                         atomic_read(&sk->sk_drops));
 617         }
 618         seq_pad(seq, '\n');
 619         return 0;
 620 }
 621
 622 static const struct seq_operations pn_sock_seq_ops = {
 623         .start = pn_sock_seq_start,
 624         .next = pn_sock_seq_next,
 625         .stop = pn_sock_seq_stop,
 626         .show = pn_sock_seq_show,
 627 };
 628
 629 static int pn_sock_open(struct inode *inode, struct file *file)
 630 {
 631         return seq_open_net(inode, file, &pn_sock_seq_ops,
 632                                 sizeof(struct seq_net_private));
 633 }
 634
 635 const struct file_operations pn_sock_seq_fops = {
 636         .owner = THIS_MODULE,
 637         .open = pn_sock_open,
 638         .read = seq_read,
 639         .llseek = seq_lseek,
 640         .release = seq_release_net,
 641 };
 642 #endif
 643
 644 static struct  {
 645         struct sock *sk[256];
 646 } pnres;
 647
 648 /*
 649  * Find and hold socket based on resource.
 650  */
 651 struct sock *pn_find_sock_by_res(struct net *net, u8 res)
 652 {
 653         struct sock *sk;
 654
 655         if (!net_eq(net, &init_net))
 656                 return NULL;
 657
 658         rcu_read_lock();
 659         sk = rcu_dereference(pnres.sk[res]);
 660         if (sk)
 661                 sock_hold(sk);
 662         rcu_read_unlock();
 663         return sk;
 664 }
 665
 666 static DEFINE_MUTEX(resource_mutex);
 667
 668 int pn_sock_bind_res(struct sock *sk, u8 res)
 669 {
 670         int ret = -EADDRINUSE;
 671
 672         if (!net_eq(sock_net(sk), &init_net))
 673                 return -ENOIOCTLCMD;
 674         if (!capable(CAP_SYS_ADMIN))
 675                 return -EPERM;
 676         if (pn_socket_autobind(sk->sk_socket))
 677                 return -EAGAIN;
 678
 679         mutex_lock(&resource_mutex);
 680         if (pnres.sk[res] == NULL) {
 681                 sock_hold(sk);
 682                 rcu_assign_pointer(pnres.sk[res], sk);
 683                 ret = 0;
 684         }
 685         mutex_unlock(&resource_mutex);
 686         return ret;
 687 }
 688
 689 int pn_sock_unbind_res(struct sock *sk, u8 res)
 690 {
 691         int ret = -ENOENT;
 692
 693         if (!capable(CAP_SYS_ADMIN))
 694                 return -EPERM;
 695
 696         mutex_lock(&resource_mutex);
 697         if (pnres.sk[res] == sk) {
 698                 RCU_INIT_POINTER(pnres.sk[res], NULL);
 699                 ret = 0;
 700         }
 701         mutex_unlock(&resource_mutex);
 702
 703         if (ret == 0) {
 704                 synchronize_rcu();
 705                 sock_put(sk);
 706         }
 707         return ret;
 708 }
 709
 710 void pn_sock_unbind_all_res(struct sock *sk)
 711 {
 712         unsigned int res, match = 0;
 713
 714         mutex_lock(&resource_mutex);
 715         for (res = 0; res < 256; res++) {
 716                 if (pnres.sk[res] == sk) {
 717                         RCU_INIT_POINTER(pnres.sk[res], NULL);
 718                         match++;
 719                 }
 720         }
 721         mutex_unlock(&resource_mutex);
 722
 723         while (match > 0) {
 724                 __sock_put(sk);
 725                 match--;
 726         }
 727         /* Caller is responsible for RCU sync before final sock_put() */
 728 }
 729
 730 #ifdef CONFIG_PROC_FS
 731 static struct sock **pn_res_get_idx(struct seq_file *seq, loff_t pos)
 732 {
 733         struct net *net = seq_file_net(seq);
 734         unsigned int i;
 735
 736         if (!net_eq(net, &init_net))
 737                 return NULL;
 738
 739         for (i = 0; i < 256; i++) {
 740                 if (pnres.sk[i] == NULL)
 741                         continue;
 742                 if (!pos)
 743                         return pnres.sk + i;
 744                 pos--;
 745         }
 746         return NULL;
 747 }
 748
 749 static struct sock **pn_res_get_next(struct seq_file *seq, struct sock **sk)
 750 {
 751         struct net *net = seq_file_net(seq);
 752         unsigned int i;
 753
 754         BUG_ON(!net_eq(net, &init_net));
 755
 756         for (i = (sk - pnres.sk) + 1; i < 256; i++)
 757                 if (pnres.sk[i])
 758                         return pnres.sk + i;
 759         return NULL;
 760 }
 761
 762 static void *pn_res_seq_start(struct seq_file *seq, loff_t *pos)
 763         __acquires(resource_mutex)
 764 {
 765         mutex_lock(&resource_mutex);
 766         return *pos ? pn_res_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 767 }
 768
 769 static void *pn_res_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 770 {
 771         struct sock **sk;
 772
 773         if (v == SEQ_START_TOKEN)
 774                 sk = pn_res_get_idx(seq, 0);
 775         else
 776                 sk = pn_res_get_next(seq, v);
 777         (*pos)++;
 778         return sk;
 779 }
 780
 781 static void pn_res_seq_stop(struct seq_file *seq, void *v)
 782         __releases(resource_mutex)
 783 {
 784         mutex_unlock(&resource_mutex);
 785 }
 786
 787 static int pn_res_seq_show(struct seq_file *seq, void *v)
 788 {
 789         seq_setwidth(seq, 63);
 790         if (v == SEQ_START_TOKEN)
 791                 seq_puts(seq, "rs   uid inode");
 792         else {
 793                 struct sock **psk = v;
 794                 struct sock *sk = *psk;
 795
 796                 seq_printf(seq, "%02X %5u %lu",
 797                            (int) (psk - pnres.sk),
 798                            from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
 799                            sock_i_ino(sk));
 800         }
 801         seq_pad(seq, '\n');
 802         return 0;
 803 }
 804
 805 static const struct seq_operations pn_res_seq_ops = {
 806         .start = pn_res_seq_start,
 807         .next = pn_res_seq_next,
 808         .stop = pn_res_seq_stop,
 809         .show = pn_res_seq_show,
 810 };
 811
 812 static int pn_res_open(struct inode *inode, struct file *file)
 813 {
 814         return seq_open_net(inode, file, &pn_res_seq_ops,
 815                                 sizeof(struct seq_net_private));
 816 }
 817
 818 const struct file_operations pn_res_seq_fops = {
 819         .owner = THIS_MODULE,
 820         .open = pn_res_open,
 821         .read = seq_read,
 822         .llseek = seq_lseek,
 823         .release = seq_release_net,
 824 };
 825 #endif