net/socket.c

   1 /*
   2  * NET          An implementation of the SOCKET network access protocol.
   3  *
   4  * Version:     @(#)socket.c    1.1.93  18/02/95
   5  *
   6  * Authors:     Orest Zborowski, <obz@Kodak.COM>
   7  *              Ross Biro, <bir7@leland.Stanford.Edu>
   8  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   9  *
  10  * Fixes:
  11  *              Anonymous       :       NOTSOCK/BADF cleanup. Error fix in
  12  *                                      shutdown()
  13  *              Alan Cox        :       verify_area() fixes
  14  *              Alan Cox        :       Removed DDI
  15  *              Jonathan Kamens :       SOCK_DGRAM reconnect bug
  16  *              Alan Cox        :       Moved a load of checks to the very
  17  *                                      top level.
  18  *              Alan Cox        :       Move address structures to/from user
  19  *                                      mode above the protocol layers.
  20  *              Rob Janssen     :       Allow 0 length sends.
  21  *              Alan Cox        :       Asynchronous I/O support (cribbed from the
  22  *                                      tty drivers).
  23  *              Niibe Yutaka    :       Asynchronous I/O for writes (4.4BSD style)
  24  *              Jeff Uphoff     :       Made max number of sockets command-line
  25  *                                      configurable.
  26  *              Matti Aarnio    :       Made the number of sockets dynamic,
  27  *                                      to be allocated when needed, and mr.
  28  *                                      Uphoff's max is used as max to be
  29  *                                      allowed to allocate.
  30  *              Linus           :       Argh. removed all the socket allocation
  31  *                                      altogether: it's in the inode now.
  32  *              Alan Cox        :       Made sock_alloc()/sock_release() public
  33  *                                      for NetROM and future kernel nfsd type
  34  *                                      stuff.
  35  *              Alan Cox        :       sendmsg/recvmsg basics.
  36  *              Tom Dyas        :       Export net symbols.
  37  *              Marcin Dalecki  :       Fixed problems with CONFIG_NET="n".
  38  *              Alan Cox        :       Added thread locking to sys_* calls
  39  *                                      for sockets. May have errors at the
  40  *                                      moment.
  41  *              Kevin Buhr      :       Fixed the dumb errors in the above.
  42  *              Andi Kleen      :       Some small cleanups, optimizations,
  43  *                                      and fixed a copy_from_user() bug.
  44  *
  45  *
  46  *              This program is free software; you can redistribute it and/or
  47  *              modify it under the terms of the GNU General Public License
  48  *              as published by the Free Software Foundation; either version
  49  *              2 of the License, or (at your option) any later version.
  50  *
  51  *
  52  *      This module is effectively the top level interface to the BSD socket
  53  *      paradigm.
  54  *
  55  */
  56
  57 #include <linux/config.h>
  58 #include <linux/signal.h>
  59 #include <linux/errno.h>
  60 #include <linux/sched.h>
  61 #include <linux/mm.h>
  62 #include <linux/smp.h>
  63 #include <linux/smp_lock.h>
  64 #include <linux/kernel.h>
  65 #include <linux/major.h>
  66 #include <linux/stat.h>
  67 #include <linux/socket.h>
  68 #include <linux/fcntl.h>
  69 #include <linux/file.h>
  70 #include <linux/net.h>
  71 #include <linux/interrupt.h>
  72 #include <linux/netdevice.h>
  73 #include <linux/proc_fs.h>
  74 #include <linux/firewall.h>
  75 #include <linux/wanrouter.h>
  76 #include <linux/init.h>
  77 #include <linux/poll.h>
  78
  79 #if defined(CONFIG_KMOD) && defined(CONFIG_NET)
  80 #include <linux/kmod.h>
  81 #endif
  82
  83 #include <asm/system.h>
  84 #include <asm/uaccess.h>
  85
  86 #include <linux/inet.h>
  87 #include <net/ip.h>
  88 #include <net/protocol.h>
  89 #include <net/rarp.h>
  90 #include <net/tcp.h>
  91 #include <net/udp.h>
  92 #include <linux/skbuff.h>
  93 #include <net/sock.h>
  94 #include <net/scm.h>
  95
  96
  97 static long long sock_lseek(struct file *file, long long offset, int whence);
  98 static ssize_t sock_read(struct file *file, char *buf,
  99                          size_t size, loff_t *ppos);
 100 static ssize_t sock_write(struct file *file, const char *buf,
 101                           size_t size, loff_t *ppos);
 102
 103 static int sock_close(struct inode *inode, struct file *file);
 104 static unsigned int sock_poll(struct file *file,
 105                               struct poll_table_struct *wait);
 106 static int sock_ioctl(struct inode *inode, struct file *file,
 107                       unsigned int cmd, unsigned long arg);
 108 static int sock_fasync(int fd, struct file *filp, int on);
 109
 110
 111 /*
 112  *      Socket files have a set of 'special' operations as well as the generic file ones. These don't appear
 113  *      in the operation structures but are done directly via the socketcall() multiplexor.
 114  */
 115
 116 static struct file_operations socket_file_ops = {
 117         sock_lseek,
 118         sock_read,
 119         sock_write,
 120         NULL,                   /* readdir */
 121         sock_poll,
 122         sock_ioctl,
 123         NULL,                   /* mmap */
 124         NULL,                   /* no special open code... */
 125         NULL,                   /* flush */
 126         sock_close,
 127         NULL,                   /* no fsync */
 128         sock_fasync
 129 };
 130
 131 /*
 132  *      The protocol list. Each protocol is registered in here.
 133  */
 134
 135 struct net_proto_family *net_families[NPROTO];
 136
 137 /*
 138  *      Statistics counters of the socket lists
 139  */
 140
 141 static int sockets_in_use  = 0;
 142
 143 /*
 144  *      Support routines. Move socket addresses back and forth across the kernel/user
 145  *      divide and look after the messy bits.
 146  */
 147
 148 #define MAX_SOCK_ADDR   128             /* 108 for Unix domain -
 149                                            16 for IP, 16 for IPX,
 150                                            24 for IPv6,
 151                                            about 80 for AX.25
 152                                            must be at least one bigger than
 153                                            the AF_UNIX size (see net/unix/af_unix.c
 154                                            :unix_mkname()).
 155                                          */
 156
 157 int move_addr_to_kernel(void *uaddr, int ulen, void *kaddr)
 158 {
 159         if(ulen<0||ulen>MAX_SOCK_ADDR)
 160                 return -EINVAL;
 161         if(ulen==0)
 162                 return 0;
 163         if(copy_from_user(kaddr,uaddr,ulen))
 164                 return -EFAULT;
 165         return 0;
 166 }
 167
 168 int move_addr_to_user(void *kaddr, int klen, void *uaddr, int *ulen)
 169 {
 170         int err;
 171         int len;
 172
 173         if((err=get_user(len, ulen)))
 174                 return err;
 175         if(len>klen)
 176                 len=klen;
 177         if(len<0 || len> MAX_SOCK_ADDR)
 178                 return -EINVAL;
 179         if(len)
 180         {
 181                 if(copy_to_user(uaddr,kaddr,len))
 182                         return -EFAULT;
 183         }
 184         /*
 185          *      "fromlen shall refer to the value before truncation.."
 186          *                      1003.1g
 187          */
 188         return __put_user(klen, ulen);
 189 }
 190
 191 /*
 192  *      Obtains the first available file descriptor and sets it up for use.
 193  */
 194
 195 static int get_fd(struct inode *inode)
 196 {
 197         int fd;
 198
 199         /*
 200          *      Find a file descriptor suitable for return to the user.
 201          */
 202
 203         fd = get_unused_fd();
 204         if (fd >= 0) {
 205                 struct file *file = get_empty_filp();
 206
 207                 if (!file) {
 208                         put_unused_fd(fd);
 209                         return -ENFILE;
 210                 }
 211
 212                 file->f_dentry = d_alloc_root(inode, NULL);
 213                 if (!file->f_dentry) {
 214                         put_filp(file);
 215                         put_unused_fd(fd);
 216                         return -ENOMEM;
 217                 }
 218
 219                 /*
 220                  * The socket maintains a reference to the inode, so we
 221                  * have to increment the count.
 222                  */
 223                 inode->i_count++;
 224
 225                 fd_install(fd, file);
 226                 file->f_op = &socket_file_ops;
 227                 file->f_mode = 3;
 228                 file->f_flags = O_RDWR;
 229                 file->f_pos = 0;
 230         }
 231         return fd;
 232 }
 233
 234 extern __inline__ struct socket *socki_lookup(struct inode *inode)
 235 {
 236         return &inode->u.socket_i;
 237 }
 238
 239 /*
 240  *      Go from a file number to its socket slot.
 241  */
 242
 243 extern struct socket *sockfd_lookup(int fd, int *err)
 244 {
 245         struct file *file;
 246         struct inode *inode;
 247         struct socket *sock;
 248
 249         if (!(file = fget(fd)))
 250         {
 251                 *err = -EBADF;
 252                 return NULL;
 253         }
 254
 255         inode = file->f_dentry->d_inode;
 256         if (!inode || !inode->i_sock || !(sock = socki_lookup(inode)))
 257         {
 258                 *err = -ENOTSOCK;
 259                 fput(file);
 260                 return NULL;
 261         }
 262
 263         if (sock->file != file) {
 264                 printk(KERN_ERR "socki_lookup: socket file changed!\n");
 265                 sock->file = file;
 266         }
 267         return sock;
 268 }
 269
 270 extern __inline__ void sockfd_put(struct socket *sock)
 271 {
 272         fput(sock->file);
 273 }
 274
 275 /*
 276  *      Allocate a socket.
 277  */
 278
 279 struct socket *sock_alloc(void)
 280 {
 281         struct inode * inode;
 282         struct socket * sock;
 283
 284         inode = get_empty_inode();
 285         if (!inode)
 286                 return NULL;
 287
 288         sock = socki_lookup(inode);
 289
 290         inode->i_mode = S_IFSOCK;
 291         inode->i_sock = 1;
 292         inode->i_uid = current->uid;
 293         inode->i_gid = current->gid;
 294
 295         sock->inode = inode;
 296         init_waitqueue(&sock->wait);
 297         sock->fasync_list = NULL;
 298         sock->state = SS_UNCONNECTED;
 299         sock->flags = 0;
 300         sock->ops = NULL;
 301         sock->sk = NULL;
 302         sock->file = NULL;
 303
 304         sockets_in_use++;
 305         return sock;
 306 }
 307
 308 void sock_release(struct socket *sock)
 309 {
 310         if (sock->state != SS_UNCONNECTED)
 311                 sock->state = SS_DISCONNECTING;
 312
 313         if (sock->ops)
 314                 sock->ops->release(sock, NULL);
 315
 316         if (sock->fasync_list)
 317                 printk(KERN_ERR "sock_release: fasync list not empty!\n");
 318
 319         --sockets_in_use;       /* Bookkeeping.. */
 320         sock->file=NULL;
 321         iput(sock->inode);
 322 }
 323
 324 int sock_sendmsg(struct socket *sock, struct msghdr *msg, int size)
 325 {
 326         int err;
 327         struct scm_cookie scm;
 328
 329         err = scm_send(sock, msg, &scm);
 330         if (err >= 0) {
 331                 err = sock->ops->sendmsg(sock, msg, size, &scm);
 332                 scm_destroy(&scm);
 333         }
 334         return err;
 335 }
 336
 337 int sock_recvmsg(struct socket *sock, struct msghdr *msg, int size, int flags)
 338 {
 339         struct scm_cookie scm;
 340
 341         memset(&scm, 0, sizeof(scm));
 342
 343         size = sock->ops->recvmsg(sock, msg, size, flags, &scm);
 344         if (size >= 0)
 345                 scm_recv(sock, msg, &scm, flags);
 346
 347         return size;
 348 }
 349
 350
 351 /*
 352  *      Sockets are not seekable.
 353  */
 354
 355 static long long sock_lseek(struct file *file,long long offset, int whence)
 356 {
 357         return -ESPIPE;
 358 }
 359
 360 /*
 361  *      Read data from a socket. ubuf is a user mode pointer. We make sure the user
 362  *      area ubuf...ubuf+size-1 is writable before asking the protocol.
 363  */
 364
 365 static ssize_t sock_read(struct file *file, char *ubuf,
 366                          size_t size, loff_t *ppos)
 367 {
 368         struct socket *sock;
 369         struct iovec iov;
 370         struct msghdr msg;
 371
 372         if (ppos != &file->f_pos)
 373                 return -ESPIPE;
 374         if (size==0)            /* Match SYS5 behaviour */
 375                 return 0;
 376
 377         sock = socki_lookup(file->f_dentry->d_inode);
 378
 379         msg.msg_name=NULL;
 380         msg.msg_namelen=0;
 381         msg.msg_iov=&iov;
 382         msg.msg_iovlen=1;
 383         msg.msg_control=NULL;
 384         msg.msg_controllen=0;
 385         iov.iov_base=ubuf;
 386         iov.iov_len=size;
 387
 388         return sock_recvmsg(sock, &msg, size,
 389                             !(file->f_flags & O_NONBLOCK) ? 0 : MSG_DONTWAIT);
 390 }
 391
 392
 393 /*
 394  *      Write data to a socket. We verify that the user area ubuf..ubuf+size-1
 395  *      is readable by the user process.
 396  */
 397
 398 static ssize_t sock_write(struct file *file, const char *ubuf,
 399                           size_t size, loff_t *ppos)
 400 {
 401         struct socket *sock;
 402         struct msghdr msg;
 403         struct iovec iov;
 404
 405         if (ppos != &file->f_pos)
 406                 return -ESPIPE;
 407         if(size==0)             /* Match SYS5 behaviour */
 408                 return 0;
 409
 410         sock = socki_lookup(file->f_dentry->d_inode);
 411
 412         msg.msg_name=NULL;
 413         msg.msg_namelen=0;
 414         msg.msg_iov=&iov;
 415         msg.msg_iovlen=1;
 416         msg.msg_control=NULL;
 417         msg.msg_controllen=0;
 418         msg.msg_flags=!(file->f_flags & O_NONBLOCK) ? 0 : MSG_DONTWAIT;
 419         iov.iov_base=(void *)ubuf;
 420         iov.iov_len=size;
 421
 422         return sock_sendmsg(sock, &msg, size);
 423 }
 424
 425 int sock_readv_writev(int type, struct inode * inode, struct file * file,
 426                       const struct iovec * iov, long count, long size)
 427 {
 428         struct msghdr msg;
 429         struct socket *sock;
 430
 431         sock = socki_lookup(inode);
 432
 433         msg.msg_name = NULL;
 434         msg.msg_namelen = 0;
 435         msg.msg_control = NULL;
 436         msg.msg_controllen = 0;
 437         msg.msg_iov = (struct iovec *) iov;
 438         msg.msg_iovlen = count;
 439         msg.msg_flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0;
 440
 441         /* read() does a VERIFY_WRITE */
 442         if (type == VERIFY_WRITE)
 443                 return sock_recvmsg(sock, &msg, size, msg.msg_flags);
 444         return sock_sendmsg(sock, &msg, size);
 445 }
 446
 447
 448 /*
 449  *      With an ioctl arg may well be a user mode pointer, but we don't know what to do
 450  *      with it - that's up to the protocol still.
 451  */
 452
 453 int sock_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 454            unsigned long arg)
 455 {
 456         struct socket *sock = socki_lookup(inode);
 457         return sock->ops->ioctl(sock, cmd, arg);
 458 }
 459
 460
 461 static unsigned int sock_poll(struct file *file, poll_table * wait)
 462 {
 463         struct socket *sock;
 464
 465         sock = socki_lookup(file->f_dentry->d_inode);
 466
 467         /*
 468          *      We can't return errors to poll, so it's either yes or no.
 469          */
 470
 471         return sock->ops->poll(file, sock, wait);
 472 }
 473
 474
 475 int sock_close(struct inode *inode, struct file *filp)
 476 {
 477         /*
 478          *      It was possible the inode is NULL we were
 479          *      closing an unfinished socket.
 480          */
 481
 482         if (!inode)
 483         {
 484                 printk(KERN_DEBUG "sock_close: NULL inode\n");
 485                 return 0;
 486         }
 487         sock_fasync(-1, filp, 0);
 488         sock_release(socki_lookup(inode));
 489         return 0;
 490 }
 491
 492 /*
 493  *      Update the socket async list
 494  */
 495
 496 static int sock_fasync(int fd, struct file *filp, int on)
 497 {
 498         struct fasync_struct *fa, *fna=NULL, **prev;
 499         struct socket *sock;
 500         unsigned long flags;
 501
 502         if (on)
 503         {
 504                 fna=(struct fasync_struct *)kmalloc(sizeof(struct fasync_struct), GFP_KERNEL);
 505                 if(fna==NULL)
 506                         return -ENOMEM;
 507         }
 508
 509         sock = socki_lookup(filp->f_dentry->d_inode);
 510
 511         prev=&(sock->fasync_list);
 512
 513         save_flags(flags);
 514         cli();
 515
 516         for (fa=*prev; fa!=NULL; prev=&fa->fa_next,fa=*prev)
 517                 if (fa->fa_file==filp)
 518                         break;
 519
 520         if(on)
 521         {
 522                 if(fa!=NULL)
 523                 {
 524                         fa->fa_fd=fd;
 525                         kfree_s(fna,sizeof(struct fasync_struct));
 526                         restore_flags(flags);
 527                         return 0;
 528                 }
 529                 fna->fa_file=filp;
 530                 fna->fa_fd=fd;
 531                 fna->magic=FASYNC_MAGIC;
 532                 fna->fa_next=sock->fasync_list;
 533                 sock->fasync_list=fna;
 534         }
 535         else
 536         {
 537                 if (fa!=NULL)
 538                 {
 539                         *prev=fa->fa_next;
 540                         kfree_s(fa,sizeof(struct fasync_struct));
 541                 }
 542         }
 543         restore_flags(flags);
 544         return 0;
 545 }
 546
 547 int sock_wake_async(struct socket *sock, int how)
 548 {
 549         if (!sock || !sock->fasync_list)
 550                 return -1;
 551         switch (how)
 552         {
 553         case 1:
 554                 if (sock->flags & SO_WAITDATA)
 555                         break;
 556                 goto call_kill;
 557         case 2:
 558                 if (!(sock->flags & SO_NOSPACE))
 559                         break;
 560                 sock->flags &= ~SO_NOSPACE;
 561                 /* fall through */
 562         case 0:
 563         call_kill:
 564                 kill_fasync(sock->fasync_list, SIGIO);
 565                 break;
 566         }
 567         return 0;
 568 }
 569
 570
 571 int sock_create(int family, int type, int protocol, struct socket **res)
 572 {
 573         int i;
 574         struct socket *sock;
 575
 576         /*
 577          *      Check protocol is in range
 578          */
 579         if(family<0||family>=NPROTO)
 580                 return -EINVAL;
 581
 582 #if defined(CONFIG_KMOD) && defined(CONFIG_NET)
 583         /* Attempt to load a protocol module if the find failed.
 584          *
 585          * 12/09/1996 Marcin: But! this makes REALLY only sense, if the user
 586          * requested real, full-featured networking support upon configuration.
 587          * Otherwise module support will break!
 588          */
 589         if (net_families[family]==NULL)
 590         {
 591                 char module_name[30];
 592                 sprintf(module_name,"net-pf-%d",family);
 593                 request_module(module_name);
 594         }
 595 #endif
 596
 597         if (net_families[family]==NULL)
 598                 return -EINVAL;
 599
 600 /*
 601  *      Check that this is a type that we know how to manipulate and
 602  *      the protocol makes sense here. The family can still reject the
 603  *      protocol later.
 604  */
 605
 606         if ((type != SOCK_STREAM && type != SOCK_DGRAM &&
 607              type != SOCK_SEQPACKET && type != SOCK_RAW && type != SOCK_RDM &&
 608 #ifdef CONFIG_XTP
 609                 type != SOCK_WEB  &&
 610 #endif
 611              type != SOCK_PACKET) || protocol < 0)
 612                         return -EINVAL;
 613
 614 /*
 615  *      Allocate the socket and allow the family to set things up. if
 616  *      the protocol is 0, the family is instructed to select an appropriate
 617  *      default.
 618  */
 619
 620         if (!(sock = sock_alloc()))
 621         {
 622                 printk(KERN_WARNING "socket: no more sockets\n");
 623                 return -ENFILE;         /* Not exactly a match, but its the
 624                                            closest posix thing */
 625         }
 626
 627         sock->type   = type;
 628
 629         if ((i = net_families[family]->create(sock, protocol)) < 0)
 630         {
 631                 sock_release(sock);
 632                 return i;
 633         }
 634
 635         *res = sock;
 636         return 0;
 637 }
 638
 639 asmlinkage int sys_socket(int family, int type, int protocol)
 640 {
 641         int retval;
 642         struct socket *sock;
 643
 644         lock_kernel();
 645
 646         retval = sock_create(family, type, protocol, &sock);
 647         if (retval < 0)
 648                 goto out;
 649
 650         retval = get_fd(sock->inode);
 651         if (retval < 0)
 652                 goto out_release;
 653         sock->file = fcheck(retval);
 654
 655 out:
 656         unlock_kernel();
 657         return retval;
 658
 659 out_release:
 660         sock_release(sock);
 661         goto out;
 662 }
 663
 664 /*
 665  *      Create a pair of connected sockets.
 666  */
 667
 668 asmlinkage int sys_socketpair(int family, int type, int protocol, int usockvec[2])
 669 {
 670         struct socket *sock1, *sock2;
 671         int fd1, fd2, err;
 672
 673         lock_kernel();
 674
 675         /*
 676          * Obtain the first socket and check if the underlying protocol
 677          * supports the socketpair call.
 678          */
 679
 680         err = sys_socket(family, type, protocol);
 681         if (err < 0)
 682                 goto out;
 683         fd1 = err;
 684
 685         /*
 686          * Now grab another socket
 687          */
 688         err = -EINVAL;
 689         fd2 = sys_socket(family, type, protocol);
 690         if (fd2 < 0)
 691                 goto out_close1;
 692
 693         /*
 694          * Get the sockets for the two fd's
 695          */
 696         sock1 = sockfd_lookup(fd1, &err);
 697         if (!sock1)
 698                 goto out_close2;
 699         sock2 = sockfd_lookup(fd2, &err);
 700         if (!sock2)
 701                 goto out_put1;
 702
 703         /* try to connect the two sockets together */
 704         err = sock1->ops->socketpair(sock1, sock2);
 705         if (err < 0)
 706                 goto out_put2;
 707
 708         err = put_user(fd1, &usockvec[0]);
 709         if (err)
 710                 goto out_put2;
 711         err = put_user(fd2, &usockvec[1]);
 712
 713 out_put2:
 714         sockfd_put(sock2);
 715 out_put1:
 716         sockfd_put(sock1);
 717
 718         if (err) {
 719         out_close2:
 720                 sys_close(fd2);
 721         out_close1:
 722                 sys_close(fd1);
 723         }
 724 out:
 725         unlock_kernel();
 726         return err;
 727 }
 728
 729
 730 /*
 731  *      Bind a name to a socket. Nothing much to do here since it's
 732  *      the protocol's responsibility to handle the local address.
 733  *
 734  *      We move the socket address to kernel space before we call
 735  *      the protocol layer (having also checked the address is ok).
 736  */
 737
 738 asmlinkage int sys_bind(int fd, struct sockaddr *umyaddr, int addrlen)
 739 {
 740         struct socket *sock;
 741         char address[MAX_SOCK_ADDR];
 742         int err;
 743
 744         lock_kernel();
 745         if((sock = sockfd_lookup(fd,&err))!=NULL)
 746         {
 747                 if((err=move_addr_to_kernel(umyaddr,addrlen,address))>=0)
 748                         err = sock->ops->bind(sock, (struct sockaddr *)address, addrlen);
 749                 sockfd_put(sock);
 750         }
 751         unlock_kernel();
 752         return err;
 753 }
 754
 755
 756 /*
 757  *      Perform a listen. Basically, we allow the protocol to do anything
 758  *      necessary for a listen, and if that works, we mark the socket as
 759  *      ready for listening.
 760  */
 761
 762 asmlinkage int sys_listen(int fd, int backlog)
 763 {
 764         struct socket *sock;
 765         int err;
 766
 767         lock_kernel();
 768         if((sock = sockfd_lookup(fd, &err))!=NULL)
 769         {
 770                 err=sock->ops->listen(sock, backlog);
 771                 sockfd_put(sock);
 772         }
 773         unlock_kernel();
 774         return err;
 775 }
 776
 777
 778 /*
 779  *      For accept, we attempt to create a new socket, set up the link
 780  *      with the client, wake up the client, then return the new
 781  *      connected fd. We collect the address of the connector in kernel
 782  *      space and move it to user at the very end. This is unclean because
 783  *      we open the socket then return an error.
 784  *
 785  *      1003.1g adds the ability to recvmsg() to query connection pending
 786  *      status to recvmsg. We need to add that support in a way thats
 787  *      clean when we restucture accept also.
 788  */
 789
 790 asmlinkage int sys_accept(int fd, struct sockaddr *upeer_sockaddr, int *upeer_addrlen)
 791 {
 792         struct inode *inode;
 793         struct socket *sock, *newsock;
 794         int err, len;
 795         char address[MAX_SOCK_ADDR];
 796
 797         lock_kernel();
 798         sock = sockfd_lookup(fd, &err);
 799         if (!sock)
 800                 goto out;
 801
 802 restart:
 803         err = -EMFILE;
 804         if (!(newsock = sock_alloc()))
 805                 goto out_put;
 806
 807         inode = newsock->inode;
 808         newsock->type = sock->type;
 809
 810         err = sock->ops->dup(newsock, sock);
 811         if (err < 0)
 812                 goto out_release;
 813
 814         err = newsock->ops->accept(sock, newsock, sock->file->f_flags);
 815         if (err < 0)
 816                 goto out_release;
 817         newsock = socki_lookup(inode);
 818
 819         if ((err = get_fd(inode)) < 0)
 820                 goto out_release;
 821         newsock->file = fcheck(err);
 822
 823         if (upeer_sockaddr)
 824         {
 825                 /* Handle the race where the accept works and we
 826                    then getname after it has closed again */
 827                 if(newsock->ops->getname(newsock, (struct sockaddr *)address, &len, 1)<0)
 828                 {
 829                         sys_close(err);
 830                         goto restart;
 831                 }
 832                 /* N.B. Should check for errors here */
 833                 move_addr_to_user(address, len, upeer_sockaddr, upeer_addrlen);
 834         }
 835
 836 out_put:
 837         sockfd_put(sock);
 838 out:
 839         unlock_kernel();
 840         return err;
 841
 842 out_release:
 843         sock_release(newsock);
 844         goto out_put;
 845 }
 846
 847
 848 /*
 849  *      Attempt to connect to a socket with the server address.  The address
 850  *      is in user space so we verify it is OK and move it to kernel space.
 851  *
 852  *      For 1003.1g we need to add clean support for a bind to AF_UNSPEC to
 853  *      break bindings
 854  *
 855  *      NOTE: 1003.1g draft 6.3 is broken with respect to AX.25/NetROM and
 856  *      other SEQPACKET protocols that take time to connect() as it doesn't
 857  *      include the -EINPROGRESS status for such sockets.
 858  */
 859
 860 asmlinkage int sys_connect(int fd, struct sockaddr *uservaddr, int addrlen)
 861 {
 862         struct socket *sock;
 863         char address[MAX_SOCK_ADDR];
 864         int err;
 865
 866         lock_kernel();
 867         sock = sockfd_lookup(fd, &err);
 868         if (!sock)
 869                 goto out;
 870         err = move_addr_to_kernel(uservaddr, addrlen, address);
 871         if (err < 0)
 872                 goto out_put;
 873         err = sock->ops->connect(sock, (struct sockaddr *) address, addrlen,
 874                                  sock->file->f_flags);
 875 out_put:
 876         sockfd_put(sock);
 877 out:
 878         unlock_kernel();
 879         return err;
 880 }
 881
 882 /*
 883  *      Get the local address ('name') of a socket object. Move the obtained
 884  *      name to user space.
 885  */
 886
 887 asmlinkage int sys_getsockname(int fd, struct sockaddr *usockaddr, int *usockaddr_len)
 888 {
 889         struct socket *sock;
 890         char address[MAX_SOCK_ADDR];
 891         int len, err;
 892
 893         lock_kernel();
 894         sock = sockfd_lookup(fd, &err);
 895         if (!sock)
 896                 goto out;
 897         err = sock->ops->getname(sock, (struct sockaddr *)address, &len, 0);
 898         if (err)
 899                 goto out_put;
 900         err = move_addr_to_user(address, len, usockaddr, usockaddr_len);
 901
 902 out_put:
 903         sockfd_put(sock);
 904 out:
 905         unlock_kernel();
 906         return err;
 907 }
 908
 909 /*
 910  *      Get the remote address ('name') of a socket object. Move the obtained
 911  *      name to user space.
 912  */
 913
 914 asmlinkage int sys_getpeername(int fd, struct sockaddr *usockaddr, int *usockaddr_len)
 915 {
 916         struct socket *sock;
 917         char address[MAX_SOCK_ADDR];
 918         int len, err;
 919
 920         lock_kernel();
 921         if ((sock = sockfd_lookup(fd, &err))!=NULL)
 922         {
 923                 err = sock->ops->getname(sock, (struct sockaddr *)address, &len, 1);
 924                 if (!err)
 925                         err=move_addr_to_user(address,len, usockaddr, usockaddr_len);
 926                 sockfd_put(sock);
 927         }
 928         unlock_kernel();
 929         return err;
 930 }
 931
 932 /*
 933  *      Send a datagram down a socket. The datagram as with write() is
 934  *      in user space. We check it can be read.
 935  */
 936
 937 asmlinkage int sys_send(int fd, void * buff, size_t len, unsigned flags)
 938 {
 939         struct socket *sock;
 940         int err;
 941         struct msghdr msg;
 942         struct iovec iov;
 943
 944         lock_kernel();
 945         sock = sockfd_lookup(fd, &err);
 946         if (sock) {
 947                 iov.iov_base=buff;
 948                 iov.iov_len=len;
 949                 msg.msg_name=NULL;
 950                 msg.msg_namelen=0;
 951                 msg.msg_iov=&iov;
 952                 msg.msg_iovlen=1;
 953                 msg.msg_control=NULL;
 954                 msg.msg_controllen=0;
 955                 if (sock->file->f_flags & O_NONBLOCK)
 956                         flags |= MSG_DONTWAIT;
 957                 msg.msg_flags = flags;
 958                 err = sock_sendmsg(sock, &msg, len);
 959
 960                 sockfd_put(sock);
 961         }
 962         unlock_kernel();
 963         return err;
 964 }
 965
 966 /*
 967  *      Send a datagram to a given address. We move the address into kernel
 968  *      space and check the user space data area is readable before invoking
 969  *      the protocol.
 970  */
 971
 972 asmlinkage int sys_sendto(int fd, void * buff, size_t len, unsigned flags,
 973            struct sockaddr *addr, int addr_len)
 974 {
 975         struct socket *sock;
 976         char address[MAX_SOCK_ADDR];
 977         int err;
 978         struct msghdr msg;
 979         struct iovec iov;
 980
 981         lock_kernel();
 982         sock = sockfd_lookup(fd, &err);
 983         if (!sock)
 984                 goto out;
 985         iov.iov_base=buff;
 986         iov.iov_len=len;
 987         msg.msg_name=NULL;
 988         msg.msg_iov=&iov;
 989         msg.msg_iovlen=1;
 990         msg.msg_control=NULL;
 991         msg.msg_controllen=0;
 992         msg.msg_namelen=addr_len;
 993         if(addr)
 994         {
 995                 err = move_addr_to_kernel(addr, addr_len, address);
 996                 if (err < 0)
 997                         goto out_put;
 998                 msg.msg_name=address;
 999         }
1000         if (sock->file->f_flags & O_NONBLOCK)
1001                 flags |= MSG_DONTWAIT;
1002         msg.msg_flags = flags;
1003         err = sock_sendmsg(sock, &msg, len);
1004
1005 out_put:
1006         sockfd_put(sock);
1007 out:
1008         unlock_kernel();
1009         return err;
1010 }
1011
1012
1013 /*
1014  *      Receive a frame from the socket and optionally record the address of the
1015  *      sender. We verify the buffers are writable and if needed move the
1016  *      sender address from kernel to user space.
1017  */
1018
1019 asmlinkage int sys_recvfrom(int fd, void * ubuf, size_t size, unsigned flags,
1020              struct sockaddr *addr, int *addr_len)
1021 {
1022         struct socket *sock;
1023         struct iovec iov;
1024         struct msghdr msg;
1025         char address[MAX_SOCK_ADDR];
1026         int err,err2;
1027
1028         lock_kernel();
1029         sock = sockfd_lookup(fd, &err);
1030         if (!sock)
1031                 goto out;
1032
1033         msg.msg_control=NULL;
1034         msg.msg_controllen=0;
1035         msg.msg_iovlen=1;
1036         msg.msg_iov=&iov;
1037         iov.iov_len=size;
1038         iov.iov_base=ubuf;
1039         msg.msg_name=address;
1040         msg.msg_namelen=MAX_SOCK_ADDR;
1041         if (sock->file->f_flags & O_NONBLOCK)
1042                 flags |= MSG_DONTWAIT;
1043         err=sock_recvmsg(sock, &msg, size, flags);
1044
1045         if(err >= 0 && addr != NULL)
1046         {
1047                 err2=move_addr_to_user(address, msg.msg_namelen, addr, addr_len);
1048                 if(err2<0)
1049                         err=err2;
1050         }
1051         sockfd_put(sock);
1052 out:
1053         unlock_kernel();
1054         return err;
1055 }
1056
1057 /*
1058  *      Receive a datagram from a socket.
1059  */
1060
1061 asmlinkage int sys_recv(int fd, void * ubuf, size_t size, unsigned flags)
1062 {
1063         return sys_recvfrom(fd,ubuf,size,flags, NULL, NULL);
1064 }
1065
1066 /*
1067  *      Set a socket option. Because we don't know the option lengths we have
1068  *      to pass the user mode parameter for the protocols to sort out.
1069  */
1070
1071 asmlinkage int sys_setsockopt(int fd, int level, int optname, char *optval, int optlen)
1072 {
1073         int err;
1074         struct socket *sock;
1075
1076         lock_kernel();
1077         if ((sock = sockfd_lookup(fd, &err))!=NULL)
1078         {
1079                 if (level == SOL_SOCKET)
1080                         err=sock_setsockopt(sock,level,optname,optval,optlen);
1081                 else
1082                         err=sock->ops->setsockopt(sock, level, optname, optval, optlen);
1083                 sockfd_put(sock);
1084         }
1085         unlock_kernel();
1086         return err;
1087 }
1088
1089 /*
1090  *      Get a socket option. Because we don't know the option lengths we have
1091  *      to pass a user mode parameter for the protocols to sort out.
1092  */
1093
1094 asmlinkage int sys_getsockopt(int fd, int level, int optname, char *optval, int *optlen)
1095 {
1096         int err;
1097         struct socket *sock;
1098
1099         lock_kernel();
1100         if ((sock = sockfd_lookup(fd, &err))!=NULL)
1101         {
1102                 if (level == SOL_SOCKET)
1103                         err=sock_getsockopt(sock,level,optname,optval,optlen);
1104                 else
1105                         err=sock->ops->getsockopt(sock, level, optname, optval, optlen);
1106                 sockfd_put(sock);
1107         }
1108         unlock_kernel();
1109         return err;
1110 }
1111
1112
1113 /*
1114  *      Shutdown a socket.
1115  */
1116
1117 asmlinkage int sys_shutdown(int fd, int how)
1118 {
1119         int err;
1120         struct socket *sock;
1121
1122         lock_kernel();
1123         if ((sock = sockfd_lookup(fd, &err))!=NULL)
1124         {
1125                 err=sock->ops->shutdown(sock, how);
1126                 sockfd_put(sock);
1127         }
1128         unlock_kernel();
1129         return err;
1130 }
1131
1132 /*
1133  *      BSD sendmsg interface
1134  */
1135
1136 asmlinkage int sys_sendmsg(int fd, struct msghdr *msg, unsigned flags)
1137 {
1138         struct socket *sock;
1139         char address[MAX_SOCK_ADDR];
1140         struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1141         unsigned char ctl[sizeof(struct cmsghdr) + 20]; /* 20 is size of ipv6_pktinfo */
1142         unsigned char *ctl_buf = ctl;
1143         struct msghdr msg_sys;
1144         int err, ctl_len, iov_size, total_len;
1145
1146         lock_kernel();
1147
1148         err = -EFAULT;
1149         if (copy_from_user(&msg_sys,msg,sizeof(struct msghdr)))
1150                 goto out;
1151
1152         sock = sockfd_lookup(fd, &err);
1153         if (!sock)
1154                 goto out;
1155
1156         /* do not move before msg_sys is valid */
1157         err = -EINVAL;
1158         if (msg_sys.msg_iovlen > UIO_MAXIOV)
1159                 goto out_put;
1160
1161         /* Check whether to allocate the iovec area*/
1162         err = -ENOMEM;
1163         iov_size = msg_sys.msg_iovlen * sizeof(struct iovec);
1164         if (msg_sys.msg_iovlen > 1 /* UIO_FASTIOV */) {
1165                 iov = sock_kmalloc(sock->sk, iov_size, GFP_KERNEL);
1166                 if (!iov)
1167                         goto out_put;
1168         }
1169
1170         /* This will also move the address data into kernel space */
1171         err = verify_iovec(&msg_sys, iov, address, VERIFY_READ);
1172         if (err < 0)
1173                 goto out_freeiov;
1174         total_len = err;
1175
1176         ctl_len = msg_sys.msg_controllen;
1177         if (ctl_len)
1178         {
1179                 if (ctl_len > sizeof(ctl))
1180                 {
1181                         /* Suggested by the Advanced Sockets API for IPv6 draft:
1182                          * Limit the msg_controllen size by the SO_SNDBUF size.
1183                          */
1184                         /* Note - when this code becomes multithreaded on
1185                          * SMP machines you have a race to fix here.
1186                          */
1187                         err = -ENOBUFS;
1188                         ctl_buf = sock_kmalloc(sock->sk, ctl_len, GFP_KERNEL);
1189                         if (ctl_buf == NULL)
1190                                 goto out_freeiov;
1191                 }
1192                 err = -EFAULT;
1193                 if (copy_from_user(ctl_buf, msg_sys.msg_control, ctl_len))
1194                         goto out_freectl;
1195                 msg_sys.msg_control = ctl_buf;
1196         }
1197         msg_sys.msg_flags = flags;
1198
1199         if (sock->file->f_flags & O_NONBLOCK)
1200                 msg_sys.msg_flags |= MSG_DONTWAIT;
1201         err = sock_sendmsg(sock, &msg_sys, total_len);
1202
1203 out_freectl:
1204         if (ctl_buf != ctl)
1205                 sock_kfree_s(sock->sk, ctl_buf, ctl_len);
1206 out_freeiov:
1207         if (iov != iovstack)
1208                 sock_kfree_s(sock->sk, iov, iov_size);
1209 out_put:
1210         sockfd_put(sock);
1211 out:
1212         unlock_kernel();
1213         return err;
1214 }
1215
1216 /*
1217  *      BSD recvmsg interface
1218  */
1219
1220 asmlinkage int sys_recvmsg(int fd, struct msghdr *msg, unsigned int flags)
1221 {
1222         struct socket *sock;
1223         struct iovec iovstack[UIO_FASTIOV];
1224         struct iovec *iov=iovstack;
1225         struct msghdr msg_sys;
1226         unsigned long cmsg_ptr;
1227         int err, iov_size, total_len, len;
1228
1229         /* kernel mode address */
1230         char addr[MAX_SOCK_ADDR];
1231
1232         /* user mode address pointers */
1233         struct sockaddr *uaddr;
1234         int *uaddr_len;
1235
1236         lock_kernel();
1237         err=-EFAULT;
1238         if (copy_from_user(&msg_sys,msg,sizeof(struct msghdr)))
1239                 goto out;
1240
1241         sock = sockfd_lookup(fd, &err);
1242         if (!sock)
1243                 goto out;
1244
1245         err = -EINVAL;
1246         if (msg_sys.msg_iovlen > UIO_MAXIOV)
1247                 goto out_put;
1248
1249         /* Check whether to allocate the iovec area*/
1250         err = -ENOMEM;
1251         iov_size = msg_sys.msg_iovlen * sizeof(struct iovec);
1252         if (msg_sys.msg_iovlen > UIO_FASTIOV) {
1253                 iov = sock_kmalloc(sock->sk, iov_size, GFP_KERNEL);
1254                 if (!iov)
1255                         goto out_put;
1256         }
1257
1258         /*
1259          *      Save the user-mode address (verify_iovec will change the
1260          *      kernel msghdr to use the kernel address space)
1261          */
1262
1263         uaddr = msg_sys.msg_name;
1264         uaddr_len = &msg->msg_namelen;
1265         err = verify_iovec(&msg_sys, iov, addr, VERIFY_WRITE);
1266         if (err < 0)
1267                 goto out_freeiov;
1268         total_len=err;
1269
1270         cmsg_ptr = (unsigned long)msg_sys.msg_control;
1271         msg_sys.msg_flags = 0;
1272
1273         if (sock->file->f_flags & O_NONBLOCK)
1274                 flags |= MSG_DONTWAIT;
1275         err = sock_recvmsg(sock, &msg_sys, total_len, flags);
1276         if (err < 0)
1277                 goto out_freeiov;
1278         len = err;
1279
1280         if (uaddr != NULL) {
1281                 err = move_addr_to_user(addr, msg_sys.msg_namelen, uaddr, uaddr_len);
1282                 if (err < 0)
1283                         goto out_freeiov;
1284         }
1285         err = __put_user(msg_sys.msg_flags, &msg->msg_flags);
1286         if (err)
1287                 goto out_freeiov;
1288         err = __put_user((unsigned long)msg_sys.msg_control-cmsg_ptr,
1289                                                          &msg->msg_controllen);
1290         if (err)
1291                 goto out_freeiov;
1292         err = len;
1293
1294 out_freeiov:
1295         if (iov != iovstack)
1296                 sock_kfree_s(sock->sk, iov, iov_size);
1297 out_put:
1298         sockfd_put(sock);
1299 out:
1300         unlock_kernel();
1301         return err;
1302 }
1303
1304
1305 /*
1306  *      Perform a file control on a socket file descriptor.
1307  *
1308  *      FIXME: does this need an fd lock ?
1309  */
1310
1311 int sock_fcntl(struct file *filp, unsigned int cmd, unsigned long arg)
1312 {
1313         struct socket *sock;
1314
1315         sock = socki_lookup (filp->f_dentry->d_inode);
1316         if (sock && sock->ops)
1317                 return sock->ops->fcntl(sock, cmd, arg);
1318         return(-EINVAL);
1319 }
1320
1321 /* Argument list sizes for sys_socketcall */
1322 #define AL(x) ((x) * sizeof(unsigned long))
1323 static unsigned char nargs[18]={AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
1324                                 AL(3),AL(3),AL(4),AL(4),AL(4),AL(6),
1325                                 AL(6),AL(2),AL(5),AL(5),AL(3),AL(3)};
1326 #undef AL
1327
1328 /*
1329  *      System call vectors.
1330  *
1331  *      Argument checking cleaned up. Saved 20% in size.
1332  *  This function doesn't need to set the kernel lock because
1333  *  it is set by the callees.
1334  */
1335
1336 asmlinkage int sys_socketcall(int call, unsigned long *args)
1337 {
1338         unsigned long a[6];
1339         unsigned long a0,a1;
1340         int err;
1341
1342         if(call<1||call>SYS_RECVMSG)
1343                 return -EINVAL;
1344
1345         /* copy_from_user should be SMP safe. */
1346         if (copy_from_user(a, args, nargs[call]))
1347                 return -EFAULT;
1348
1349         a0=a[0];
1350         a1=a[1];
1351
1352         switch(call)
1353         {
1354                 case SYS_SOCKET:
1355                         err = sys_socket(a0,a1,a[2]);
1356                         break;
1357                 case SYS_BIND:
1358                         err = sys_bind(a0,(struct sockaddr *)a1, a[2]);
1359                         break;
1360                 case SYS_CONNECT:
1361                         err = sys_connect(a0, (struct sockaddr *)a1, a[2]);
1362                         break;
1363                 case SYS_LISTEN:
1364                         err = sys_listen(a0,a1);
1365                         break;
1366                 case SYS_ACCEPT:
1367                         err = sys_accept(a0,(struct sockaddr *)a1, (int *)a[2]);
1368                         break;
1369                 case SYS_GETSOCKNAME:
1370                         err = sys_getsockname(a0,(struct sockaddr *)a1, (int *)a[2]);
1371                         break;
1372                 case SYS_GETPEERNAME:
1373                         err = sys_getpeername(a0, (struct sockaddr *)a1, (int *)a[2]);
1374                         break;
1375                 case SYS_SOCKETPAIR:
1376                         err = sys_socketpair(a0,a1, a[2], (int *)a[3]);
1377                         break;
1378                 case SYS_SEND:
1379                         err = sys_send(a0, (void *)a1, a[2], a[3]);
1380                         break;
1381                 case SYS_SENDTO:
1382                         err = sys_sendto(a0,(void *)a1, a[2], a[3],
1383                                          (struct sockaddr *)a[4], a[5]);
1384                         break;
1385                 case SYS_RECV:
1386                         err = sys_recv(a0, (void *)a1, a[2], a[3]);
1387                         break;
1388                 case SYS_RECVFROM:
1389                         err = sys_recvfrom(a0, (void *)a1, a[2], a[3],
1390                                            (struct sockaddr *)a[4], (int *)a[5]);
1391                         break;
1392                 case SYS_SHUTDOWN:
1393                         err = sys_shutdown(a0,a1);
1394                         break;
1395                 case SYS_SETSOCKOPT:
1396                         err = sys_setsockopt(a0, a1, a[2], (char *)a[3], a[4]);
1397                         break;
1398                 case SYS_GETSOCKOPT:
1399                         err = sys_getsockopt(a0, a1, a[2], (char *)a[3], (int *)a[4]);
1400                         break;
1401                 case SYS_SENDMSG:
1402                         err = sys_sendmsg(a0, (struct msghdr *) a1, a[2]);
1403                         break;
1404                 case SYS_RECVMSG:
1405                         err = sys_recvmsg(a0, (struct msghdr *) a1, a[2]);
1406                         break;
1407                 default:
1408                         err = -EINVAL;
1409                         break;
1410         }
1411         return err;
1412 }
1413
1414 /*
1415  *      This function is called by a protocol handler that wants to
1416  *      advertise its address family, and have it linked into the
1417  *      SOCKET module.
1418  */
1419
1420 int sock_register(struct net_proto_family *ops)
1421 {
1422         if (ops->family >= NPROTO) {
1423                 printk(KERN_CRIT "protocol %d >= NPROTO(%d)\n", ops->family, NPROTO);
1424                 return -ENOBUFS;
1425         }
1426         net_families[ops->family]=ops;
1427         return 0;
1428 }
1429
1430 /*
1431  *      This function is called by a protocol handler that wants to
1432  *      remove its address family, and have it unlinked from the
1433  *      SOCKET module.
1434  */
1435
1436 int sock_unregister(int family)
1437 {
1438         if (family < 0 || family >= NPROTO)
1439                 return -1;
1440
1441         net_families[family]=NULL;
1442         return 0;
1443 }
1444
1445 void __init proto_init(void)
1446 {
1447         extern struct net_proto protocols[];    /* Network protocols */
1448         struct net_proto *pro;
1449
1450         /* Kick all configured protocols. */
1451         pro = protocols;
1452         while (pro->name != NULL)
1453         {
1454                 (*pro->init_func)(pro);
1455                 pro++;
1456         }
1457         /* We're all done... */
1458 }
1459
1460 extern void sk_init(void);
1461 #ifdef CONFIG_WAN_ROUTER
1462 extern void wanrouter_init(void);
1463 #endif
1464
1465 void __init sock_init(void)
1466 {
1467         int i;
1468
1469         printk(KERN_INFO "Swansea University Computer Society NET3.039 for Linux 2.1\n");
1470
1471         /*
1472          *      Initialize all address (protocol) families.
1473          */
1474
1475         for (i = 0; i < NPROTO; i++)
1476                 net_families[i] = NULL;
1477
1478         /*
1479          *      Initialize sock SLAB cache.
1480          */
1481
1482         sk_init();
1483
1484 #ifdef SLAB_SKB
1485         /*
1486          *      Initialize skbuff SLAB cache
1487          */
1488         skb_init();
1489 #endif
1490
1491
1492         /*
1493          *      Wan router layer.
1494          */
1495
1496 #ifdef CONFIG_WAN_ROUTER
1497         wanrouter_init();
1498 #endif
1499
1500         /*
1501          *      Attach the firewall module if configured
1502          */
1503
1504 #ifdef CONFIG_FIREWALL
1505         fwchain_init();
1506 #endif
1507
1508         /*
1509          *      Initialize the protocols module.
1510          */
1511
1512         proto_init();
1513
1514         /*
1515          *      The netlink device handler may be needed early.
1516          */
1517
1518 #ifdef  CONFIG_RTNETLINK
1519         rtnetlink_init();
1520 #endif
1521 #ifdef CONFIG_NETLINK_DEV
1522         init_netlink();
1523 #endif
1524 }
1525
1526 int socket_get_info(char *buffer, char **start, off_t offset, int length)
1527 {
1528         int len = sprintf(buffer, "sockets: used %d\n", sockets_in_use);
1529         if (offset >= len)
1530         {
1531                 *start = buffer;
1532                 return 0;
1533         }
1534         *start = buffer + offset;
1535         len -= offset;
1536         if (len > length)
1537                 len = length;
1538         return len;
1539 }