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 void 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 EXPORT_SYMBOL(pn_sock_hash);
 152
 153 void pn_sock_unhash(struct sock *sk)
 154 {
 155         mutex_lock(&pnsocks.lock);
 156         sk_del_node_init_rcu(sk);
 157         mutex_unlock(&pnsocks.lock);
 158         pn_sock_unbind_all_res(sk);
 159         synchronize_rcu();
 160 }
 161 EXPORT_SYMBOL(pn_sock_unhash);
 162
 163 static DEFINE_MUTEX(port_mutex);
 164
 165 static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
 166 {
 167         struct sock *sk = sock->sk;
 168         struct pn_sock *pn = pn_sk(sk);
 169         struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
 170         int err;
 171         u16 handle;
 172         u8 saddr;
 173
 174         if (sk->sk_prot->bind)
 175                 return sk->sk_prot->bind(sk, addr, len);
 176
 177         if (len < sizeof(struct sockaddr_pn))
 178                 return -EINVAL;
 179         if (spn->spn_family != AF_PHONET)
 180                 return -EAFNOSUPPORT;
 181
 182         handle = pn_sockaddr_get_object((struct sockaddr_pn *)addr);
 183         saddr = pn_addr(handle);
 184         if (saddr && phonet_address_lookup(sock_net(sk), saddr))
 185                 return -EADDRNOTAVAIL;
 186
 187         lock_sock(sk);
 188         if (sk->sk_state != TCP_CLOSE || pn_port(pn->sobject)) {
 189                 err = -EINVAL; /* attempt to rebind */
 190                 goto out;
 191         }
 192         WARN_ON(sk_hashed(sk));
 193         mutex_lock(&port_mutex);
 194         err = sk->sk_prot->get_port(sk, pn_port(handle));
 195         if (err)
 196                 goto out_port;
 197
 198         /* get_port() sets the port, bind() sets the address if applicable */
 199         pn->sobject = pn_object(saddr, pn_port(pn->sobject));
 200         pn->resource = spn->spn_resource;
 201
 202         /* Enable RX on the socket */
 203         sk->sk_prot->hash(sk);
 204 out_port:
 205         mutex_unlock(&port_mutex);
 206 out:
 207         release_sock(sk);
 208         return err;
 209 }
 210
 211 static int pn_socket_autobind(struct socket *sock)
 212 {
 213         struct sockaddr_pn sa;
 214         int err;
 215
 216         memset(&sa, 0, sizeof(sa));
 217         sa.spn_family = AF_PHONET;
 218         err = pn_socket_bind(sock, (struct sockaddr *)&sa,
 219                                 sizeof(struct sockaddr_pn));
 220         if (err != -EINVAL)
 221                 return err;
 222         BUG_ON(!pn_port(pn_sk(sock->sk)->sobject));
 223         return 0; /* socket was already bound */
 224 }
 225
 226 static int pn_socket_connect(struct socket *sock, struct sockaddr *addr,
 227                 int len, int flags)
 228 {
 229         struct sock *sk = sock->sk;
 230         struct pn_sock *pn = pn_sk(sk);
 231         struct sockaddr_pn *spn = (struct sockaddr_pn *)addr;
 232         struct task_struct *tsk = current;
 233         long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
 234         int err;
 235
 236         if (pn_socket_autobind(sock))
 237                 return -ENOBUFS;
 238         if (len < sizeof(struct sockaddr_pn))
 239                 return -EINVAL;
 240         if (spn->spn_family != AF_PHONET)
 241                 return -EAFNOSUPPORT;
 242
 243         lock_sock(sk);
 244
 245         switch (sock->state) {
 246         case SS_UNCONNECTED:
 247                 if (sk->sk_state != TCP_CLOSE) {
 248                         err = -EISCONN;
 249                         goto out;
 250                 }
 251                 break;
 252         case SS_CONNECTING:
 253                 err = -EALREADY;
 254                 goto out;
 255         default:
 256                 err = -EISCONN;
 257                 goto out;
 258         }
 259
 260         pn->dobject = pn_sockaddr_get_object(spn);
 261         pn->resource = pn_sockaddr_get_resource(spn);
 262         sock->state = SS_CONNECTING;
 263
 264         err = sk->sk_prot->connect(sk, addr, len);
 265         if (err) {
 266                 sock->state = SS_UNCONNECTED;
 267                 pn->dobject = 0;
 268                 goto out;
 269         }
 270
 271         while (sk->sk_state == TCP_SYN_SENT) {
 272                 DEFINE_WAIT(wait);
 273
 274                 if (!timeo) {
 275                         err = -EINPROGRESS;
 276                         goto out;
 277                 }
 278                 if (signal_pending(tsk)) {
 279                         err = sock_intr_errno(timeo);
 280                         goto out;
 281                 }
 282
 283                 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
 284                                                 TASK_INTERRUPTIBLE);
 285                 release_sock(sk);
 286                 timeo = schedule_timeout(timeo);
 287                 lock_sock(sk);
 288                 finish_wait(sk_sleep(sk), &wait);
 289         }
 290
 291         if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED))
 292                 err = 0;
 293         else if (sk->sk_state == TCP_CLOSE_WAIT)
 294                 err = -ECONNRESET;
 295         else
 296                 err = -ECONNREFUSED;
 297         sock->state = err ? SS_UNCONNECTED : SS_CONNECTED;
 298 out:
 299         release_sock(sk);
 300         return err;
 301 }
 302
 303 static int pn_socket_accept(struct socket *sock, struct socket *newsock,
 304                                 int flags)
 305 {
 306         struct sock *sk = sock->sk;
 307         struct sock *newsk;
 308         int err;
 309
 310         if (unlikely(sk->sk_state != TCP_LISTEN))
 311                 return -EINVAL;
 312
 313         newsk = sk->sk_prot->accept(sk, flags, &err);
 314         if (!newsk)
 315                 return err;
 316
 317         lock_sock(newsk);
 318         sock_graft(newsk, newsock);
 319         newsock->state = SS_CONNECTED;
 320         release_sock(newsk);
 321         return 0;
 322 }
 323
 324 static int pn_socket_getname(struct socket *sock, struct sockaddr *addr,
 325                                 int *sockaddr_len, int peer)
 326 {
 327         struct sock *sk = sock->sk;
 328         struct pn_sock *pn = pn_sk(sk);
 329
 330         memset(addr, 0, sizeof(struct sockaddr_pn));
 331         addr->sa_family = AF_PHONET;
 332         if (!peer) /* Race with bind() here is userland's problem. */
 333                 pn_sockaddr_set_object((struct sockaddr_pn *)addr,
 334                                         pn->sobject);
 335
 336         *sockaddr_len = sizeof(struct sockaddr_pn);
 337         return 0;
 338 }
 339
 340 static unsigned int pn_socket_poll(struct file *file, struct socket *sock,
 341                                         poll_table *wait)
 342 {
 343         struct sock *sk = sock->sk;
 344         struct pep_sock *pn = pep_sk(sk);
 345         unsigned int mask = 0;
 346
 347         poll_wait(file, sk_sleep(sk), wait);
 348
 349         if (sk->sk_state == TCP_CLOSE)
 350                 return POLLERR;
 351         if (!skb_queue_empty(&sk->sk_receive_queue))
 352                 mask |= POLLIN | POLLRDNORM;
 353         if (!skb_queue_empty(&pn->ctrlreq_queue))
 354                 mask |= POLLPRI;
 355         if (!mask && sk->sk_state == TCP_CLOSE_WAIT)
 356                 return POLLHUP;
 357
 358         if (sk->sk_state == TCP_ESTABLISHED &&
 359                 atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf &&
 360                 atomic_read(&pn->tx_credits))
 361                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 362
 363         return mask;
 364 }
 365
 366 static int pn_socket_ioctl(struct socket *sock, unsigned int cmd,
 367                                 unsigned long arg)
 368 {
 369         struct sock *sk = sock->sk;
 370         struct pn_sock *pn = pn_sk(sk);
 371
 372         if (cmd == SIOCPNGETOBJECT) {
 373                 struct net_device *dev;
 374                 u16 handle;
 375                 u8 saddr;
 376
 377                 if (get_user(handle, (__u16 __user *)arg))
 378                         return -EFAULT;
 379
 380                 lock_sock(sk);
 381                 if (sk->sk_bound_dev_if)
 382                         dev = dev_get_by_index(sock_net(sk),
 383                                                 sk->sk_bound_dev_if);
 384                 else
 385                         dev = phonet_device_get(sock_net(sk));
 386                 if (dev && (dev->flags & IFF_UP))
 387                         saddr = phonet_address_get(dev, pn_addr(handle));
 388                 else
 389                         saddr = PN_NO_ADDR;
 390                 release_sock(sk);
 391
 392                 if (dev)
 393                         dev_put(dev);
 394                 if (saddr == PN_NO_ADDR)
 395                         return -EHOSTUNREACH;
 396
 397                 handle = pn_object(saddr, pn_port(pn->sobject));
 398                 return put_user(handle, (__u16 __user *)arg);
 399         }
 400
 401         return sk->sk_prot->ioctl(sk, cmd, arg);
 402 }
 403
 404 static int pn_socket_listen(struct socket *sock, int backlog)
 405 {
 406         struct sock *sk = sock->sk;
 407         int err = 0;
 408
 409         if (pn_socket_autobind(sock))
 410                 return -ENOBUFS;
 411
 412         lock_sock(sk);
 413         if (sock->state != SS_UNCONNECTED) {
 414                 err = -EINVAL;
 415                 goto out;
 416         }
 417
 418         if (sk->sk_state != TCP_LISTEN) {
 419                 sk->sk_state = TCP_LISTEN;
 420                 sk->sk_ack_backlog = 0;
 421         }
 422         sk->sk_max_ack_backlog = backlog;
 423 out:
 424         release_sock(sk);
 425         return err;
 426 }
 427
 428 static int pn_socket_sendmsg(struct kiocb *iocb, struct socket *sock,
 429                                 struct msghdr *m, size_t total_len)
 430 {
 431         struct sock *sk = sock->sk;
 432
 433         if (pn_socket_autobind(sock))
 434                 return -EAGAIN;
 435
 436         return sk->sk_prot->sendmsg(iocb, sk, m, total_len);
 437 }
 438
 439 const struct proto_ops phonet_dgram_ops = {
 440         .family         = AF_PHONET,
 441         .owner          = THIS_MODULE,
 442         .release        = pn_socket_release,
 443         .bind           = pn_socket_bind,
 444         .connect        = sock_no_connect,
 445         .socketpair     = sock_no_socketpair,
 446         .accept         = sock_no_accept,
 447         .getname        = pn_socket_getname,
 448         .poll           = datagram_poll,
 449         .ioctl          = pn_socket_ioctl,
 450         .listen         = sock_no_listen,
 451         .shutdown       = sock_no_shutdown,
 452         .setsockopt     = sock_no_setsockopt,
 453         .getsockopt     = sock_no_getsockopt,
 454 #ifdef CONFIG_COMPAT
 455         .compat_setsockopt = sock_no_setsockopt,
 456         .compat_getsockopt = sock_no_getsockopt,
 457 #endif
 458         .sendmsg        = pn_socket_sendmsg,
 459         .recvmsg        = sock_common_recvmsg,
 460         .mmap           = sock_no_mmap,
 461         .sendpage       = sock_no_sendpage,
 462 };
 463
 464 const struct proto_ops phonet_stream_ops = {
 465         .family         = AF_PHONET,
 466         .owner          = THIS_MODULE,
 467         .release        = pn_socket_release,
 468         .bind           = pn_socket_bind,
 469         .connect        = pn_socket_connect,
 470         .socketpair     = sock_no_socketpair,
 471         .accept         = pn_socket_accept,
 472         .getname        = pn_socket_getname,
 473         .poll           = pn_socket_poll,
 474         .ioctl          = pn_socket_ioctl,
 475         .listen         = pn_socket_listen,
 476         .shutdown       = sock_no_shutdown,
 477         .setsockopt     = sock_common_setsockopt,
 478         .getsockopt     = sock_common_getsockopt,
 479 #ifdef CONFIG_COMPAT
 480         .compat_setsockopt = compat_sock_common_setsockopt,
 481         .compat_getsockopt = compat_sock_common_getsockopt,
 482 #endif
 483         .sendmsg        = pn_socket_sendmsg,
 484         .recvmsg        = sock_common_recvmsg,
 485         .mmap           = sock_no_mmap,
 486         .sendpage       = sock_no_sendpage,
 487 };
 488 EXPORT_SYMBOL(phonet_stream_ops);
 489
 490 /* allocate port for a socket */
 491 int pn_sock_get_port(struct sock *sk, unsigned short sport)
 492 {
 493         static int port_cur;
 494         struct net *net = sock_net(sk);
 495         struct pn_sock *pn = pn_sk(sk);
 496         struct sockaddr_pn try_sa;
 497         struct sock *tmpsk;
 498
 499         memset(&try_sa, 0, sizeof(struct sockaddr_pn));
 500         try_sa.spn_family = AF_PHONET;
 501         WARN_ON(!mutex_is_locked(&port_mutex));
 502         if (!sport) {
 503                 /* search free port */
 504                 int port, pmin, pmax;
 505
 506                 phonet_get_local_port_range(&pmin, &pmax);
 507                 for (port = pmin; port <= pmax; port++) {
 508                         port_cur++;
 509                         if (port_cur < pmin || port_cur > pmax)
 510                                 port_cur = pmin;
 511
 512                         pn_sockaddr_set_port(&try_sa, port_cur);
 513                         tmpsk = pn_find_sock_by_sa(net, &try_sa);
 514                         if (tmpsk == NULL) {
 515                                 sport = port_cur;
 516                                 goto found;
 517                         } else
 518                                 sock_put(tmpsk);
 519                 }
 520         } else {
 521                 /* try to find specific port */
 522                 pn_sockaddr_set_port(&try_sa, sport);
 523                 tmpsk = pn_find_sock_by_sa(net, &try_sa);
 524                 if (tmpsk == NULL)
 525                         /* No sock there! We can use that port... */
 526                         goto found;
 527                 else
 528                         sock_put(tmpsk);
 529         }
 530         /* the port must be in use already */
 531         return -EADDRINUSE;
 532
 533 found:
 534         pn->sobject = pn_object(pn_addr(pn->sobject), sport);
 535         return 0;
 536 }
 537 EXPORT_SYMBOL(pn_sock_get_port);
 538
 539 #ifdef CONFIG_PROC_FS
 540 static struct sock *pn_sock_get_idx(struct seq_file *seq, loff_t pos)
 541 {
 542         struct net *net = seq_file_net(seq);
 543         struct hlist_head *hlist = pnsocks.hlist;
 544         struct sock *sknode;
 545         unsigned int h;
 546
 547         for (h = 0; h < PN_HASHSIZE; h++) {
 548                 sk_for_each_rcu(sknode, hlist) {
 549                         if (!net_eq(net, sock_net(sknode)))
 550                                 continue;
 551                         if (!pos)
 552                                 return sknode;
 553                         pos--;
 554                 }
 555                 hlist++;
 556         }
 557         return NULL;
 558 }
 559
 560 static struct sock *pn_sock_get_next(struct seq_file *seq, struct sock *sk)
 561 {
 562         struct net *net = seq_file_net(seq);
 563
 564         do
 565                 sk = sk_next(sk);
 566         while (sk && !net_eq(net, sock_net(sk)));
 567
 568         return sk;
 569 }
 570
 571 static void *pn_sock_seq_start(struct seq_file *seq, loff_t *pos)
 572         __acquires(rcu)
 573 {
 574         rcu_read_lock();
 575         return *pos ? pn_sock_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 576 }
 577
 578 static void *pn_sock_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 579 {
 580         struct sock *sk;
 581
 582         if (v == SEQ_START_TOKEN)
 583                 sk = pn_sock_get_idx(seq, 0);
 584         else
 585                 sk = pn_sock_get_next(seq, v);
 586         (*pos)++;
 587         return sk;
 588 }
 589
 590 static void pn_sock_seq_stop(struct seq_file *seq, void *v)
 591         __releases(rcu)
 592 {
 593         rcu_read_unlock();
 594 }
 595
 596 static int pn_sock_seq_show(struct seq_file *seq, void *v)
 597 {
 598         seq_setwidth(seq, 127);
 599         if (v == SEQ_START_TOKEN)
 600                 seq_puts(seq, "pt  loc  rem rs st tx_queue rx_queue "
 601                         "  uid inode ref pointer drops");
 602         else {
 603                 struct sock *sk = v;
 604                 struct pn_sock *pn = pn_sk(sk);
 605
 606                 seq_printf(seq, "%2d %04X:%04X:%02X %02X %08X:%08X %5d %lu "
 607                         "%d %pK %d",
 608                         sk->sk_protocol, pn->sobject, pn->dobject,
 609                         pn->resource, sk->sk_state,
 610                         sk_wmem_alloc_get(sk), sk_rmem_alloc_get(sk),
 611                         from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
 612                         sock_i_ino(sk),
 613                         atomic_read(&sk->sk_refcnt), sk,
 614                         atomic_read(&sk->sk_drops));
 615         }
 616         seq_pad(seq, '\n');
 617         return 0;
 618 }
 619
 620 static const struct seq_operations pn_sock_seq_ops = {
 621         .start = pn_sock_seq_start,
 622         .next = pn_sock_seq_next,
 623         .stop = pn_sock_seq_stop,
 624         .show = pn_sock_seq_show,
 625 };
 626
 627 static int pn_sock_open(struct inode *inode, struct file *file)
 628 {
 629         return seq_open_net(inode, file, &pn_sock_seq_ops,
 630                                 sizeof(struct seq_net_private));
 631 }
 632
 633 const struct file_operations pn_sock_seq_fops = {
 634         .owner = THIS_MODULE,
 635         .open = pn_sock_open,
 636         .read = seq_read,
 637         .llseek = seq_lseek,
 638         .release = seq_release_net,
 639 };
 640 #endif
 641
 642 static struct  {
 643         struct sock *sk[256];
 644 } pnres;
 645
 646 /*
 647  * Find and hold socket based on resource.
 648  */
 649 struct sock *pn_find_sock_by_res(struct net *net, u8 res)
 650 {
 651         struct sock *sk;
 652
 653         if (!net_eq(net, &init_net))
 654                 return NULL;
 655
 656         rcu_read_lock();
 657         sk = rcu_dereference(pnres.sk[res]);
 658         if (sk)
 659                 sock_hold(sk);
 660         rcu_read_unlock();
 661         return sk;
 662 }
 663
 664 static DEFINE_MUTEX(resource_mutex);
 665
 666 int pn_sock_bind_res(struct sock *sk, u8 res)
 667 {
 668         int ret = -EADDRINUSE;
 669
 670         if (!net_eq(sock_net(sk), &init_net))
 671                 return -ENOIOCTLCMD;
 672         if (!capable(CAP_SYS_ADMIN))
 673                 return -EPERM;
 674         if (pn_socket_autobind(sk->sk_socket))
 675                 return -EAGAIN;
 676
 677         mutex_lock(&resource_mutex);
 678         if (pnres.sk[res] == NULL) {
 679                 sock_hold(sk);
 680                 rcu_assign_pointer(pnres.sk[res], sk);
 681                 ret = 0;
 682         }
 683         mutex_unlock(&resource_mutex);
 684         return ret;
 685 }
 686
 687 int pn_sock_unbind_res(struct sock *sk, u8 res)
 688 {
 689         int ret = -ENOENT;
 690
 691         if (!capable(CAP_SYS_ADMIN))
 692                 return -EPERM;
 693
 694         mutex_lock(&resource_mutex);
 695         if (pnres.sk[res] == sk) {
 696                 RCU_INIT_POINTER(pnres.sk[res], NULL);
 697                 ret = 0;
 698         }
 699         mutex_unlock(&resource_mutex);
 700
 701         if (ret == 0) {
 702                 synchronize_rcu();
 703                 sock_put(sk);
 704         }
 705         return ret;
 706 }
 707
 708 void pn_sock_unbind_all_res(struct sock *sk)
 709 {
 710         unsigned int res, match = 0;
 711
 712         mutex_lock(&resource_mutex);
 713         for (res = 0; res < 256; res++) {
 714                 if (pnres.sk[res] == sk) {
 715                         RCU_INIT_POINTER(pnres.sk[res], NULL);
 716                         match++;
 717                 }
 718         }
 719         mutex_unlock(&resource_mutex);
 720
 721         while (match > 0) {
 722                 __sock_put(sk);
 723                 match--;
 724         }
 725         /* Caller is responsible for RCU sync before final sock_put() */
 726 }
 727
 728 #ifdef CONFIG_PROC_FS
 729 static struct sock **pn_res_get_idx(struct seq_file *seq, loff_t pos)
 730 {
 731         struct net *net = seq_file_net(seq);
 732         unsigned int i;
 733
 734         if (!net_eq(net, &init_net))
 735                 return NULL;
 736
 737         for (i = 0; i < 256; i++) {
 738                 if (pnres.sk[i] == NULL)
 739                         continue;
 740                 if (!pos)
 741                         return pnres.sk + i;
 742                 pos--;
 743         }
 744         return NULL;
 745 }
 746
 747 static struct sock **pn_res_get_next(struct seq_file *seq, struct sock **sk)
 748 {
 749         struct net *net = seq_file_net(seq);
 750         unsigned int i;
 751
 752         BUG_ON(!net_eq(net, &init_net));
 753
 754         for (i = (sk - pnres.sk) + 1; i < 256; i++)
 755                 if (pnres.sk[i])
 756                         return pnres.sk + i;
 757         return NULL;
 758 }
 759
 760 static void *pn_res_seq_start(struct seq_file *seq, loff_t *pos)
 761         __acquires(resource_mutex)
 762 {
 763         mutex_lock(&resource_mutex);
 764         return *pos ? pn_res_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 765 }
 766
 767 static void *pn_res_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 768 {
 769         struct sock **sk;
 770
 771         if (v == SEQ_START_TOKEN)
 772                 sk = pn_res_get_idx(seq, 0);
 773         else
 774                 sk = pn_res_get_next(seq, v);
 775         (*pos)++;
 776         return sk;
 777 }
 778
 779 static void pn_res_seq_stop(struct seq_file *seq, void *v)
 780         __releases(resource_mutex)
 781 {
 782         mutex_unlock(&resource_mutex);
 783 }
 784
 785 static int pn_res_seq_show(struct seq_file *seq, void *v)
 786 {
 787         seq_setwidth(seq, 63);
 788         if (v == SEQ_START_TOKEN)
 789                 seq_puts(seq, "rs   uid inode");
 790         else {
 791                 struct sock **psk = v;
 792                 struct sock *sk = *psk;
 793
 794                 seq_printf(seq, "%02X %5u %lu",
 795                            (int) (psk - pnres.sk),
 796                            from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
 797                            sock_i_ino(sk));
 798         }
 799         seq_pad(seq, '\n');
 800         return 0;
 801 }
 802
 803 static const struct seq_operations pn_res_seq_ops = {
 804         .start = pn_res_seq_start,
 805         .next = pn_res_seq_next,
 806         .stop = pn_res_seq_stop,
 807         .show = pn_res_seq_show,
 808 };
 809
 810 static int pn_res_open(struct inode *inode, struct file *file)
 811 {
 812         return seq_open_net(inode, file, &pn_res_seq_ops,
 813                                 sizeof(struct seq_net_private));
 814 }
 815
 816 const struct file_operations pn_res_seq_fops = {
 817         .owner = THIS_MODULE,
 818         .open = pn_res_open,
 819         .read = seq_read,
 820         .llseek = seq_lseek,
 821         .release = seq_release_net,
 822 };
 823 #endif