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socket.c

/*
 * NET            An implementation of the SOCKET network access protocol.
 *
 * Version: @(#)socket.c      1.1.93      18/02/95
 *
 * Authors: Orest Zborowski, <obz@Kodak.COM>
 *          Ross Biro
 *          Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 * Fixes:
 *          Anonymous   :     NOTSOCK/BADF cleanup. Error fix in
 *                            shutdown()
 *          Alan Cox    :     verify_area() fixes
 *          Alan Cox    :     Removed DDI
 *          Jonathan Kamens   :     SOCK_DGRAM reconnect bug
 *          Alan Cox    :     Moved a load of checks to the very
 *                            top level.
 *          Alan Cox    :     Move address structures to/from user
 *                            mode above the protocol layers.
 *          Rob Janssen :     Allow 0 length sends.
 *          Alan Cox    :     Asynchronous I/O support (cribbed from the
 *                            tty drivers).
 *          Niibe Yutaka      :     Asynchronous I/O for writes (4.4BSD style)
 *          Jeff Uphoff :     Made max number of sockets command-line
 *                            configurable.
 *          Matti Aarnio      :     Made the number of sockets dynamic,
 *                            to be allocated when needed, and mr.
 *                            Uphoff's max is used as max to be
 *                            allowed to allocate.
 *          Linus       :     Argh. removed all the socket allocation
 *                            altogether: it's in the inode now.
 *          Alan Cox    :     Made sock_alloc()/sock_release() public
 *                            for NetROM and future kernel nfsd type
 *                            stuff.
 *          Alan Cox    :     sendmsg/recvmsg basics.
 *          Tom Dyas    :     Export net symbols.
 *          Marcin Dalecki    :     Fixed problems with CONFIG_NET="n".
 *          Alan Cox    :     Added thread locking to sys_* calls
 *                            for sockets. May have errors at the
 *                            moment.
 *          Kevin Buhr  :     Fixed the dumb errors in the above.
 *          Andi Kleen  :     Some small cleanups, optimizations,
 *                            and fixed a copy_from_user() bug.
 *          Tigran Aivazian   :     sys_send(args) calls sys_sendto(args, NULL, 0)
 *          Tigran Aivazian   :     Made listen(2) backlog sanity checks 
 *                            protocol-independent
 *
 *
 *          This program is free software; you can redistribute it and/or
 *          modify it under the terms of the GNU General Public License
 *          as published by the Free Software Foundation; either version
 *          2 of the License, or (at your option) any later version.
 *
 *
 *    This module is effectively the top level interface to the BSD socket
 *    paradigm. 
 *
 *    Based upon Swansea University Computer Society NET3.039
 */

#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/socket.h>
#include <linux/file.h>
#include <linux/net.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/mutex.h>
#include <linux/wanrouter.h>
#include <linux/if_bridge.h>
#include <linux/if_frad.h>
#include <linux/if_vlan.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/cache.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/divert.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/kmod.h>
#include <linux/audit.h>
#include <linux/wireless.h>

#include <asm/uaccess.h>
#include <asm/unistd.h>

#include <net/compat.h>

#include <net/sock.h>
#include <linux/netfilter.h>

static int sock_no_open(struct inode *irrelevant, struct file *dontcare);
static ssize_t sock_aio_read(struct kiocb *iocb, char __user *buf,
                   size_t size, loff_t pos);
static ssize_t sock_aio_write(struct kiocb *iocb, const char __user *buf,
                    size_t size, loff_t pos);
static int sock_mmap(struct file *file, struct vm_area_struct * vma);

static int sock_close(struct inode *inode, struct file *file);
static unsigned int sock_poll(struct file *file,
                        struct poll_table_struct *wait);
static long sock_ioctl(struct file *file,
                  unsigned int cmd, unsigned long arg);
#ifdef CONFIG_COMPAT
static long compat_sock_ioctl(struct file *file,
                  unsigned int cmd, unsigned long arg);
#endif
static int sock_fasync(int fd, struct file *filp, int on);
static ssize_t sock_readv(struct file *file, const struct iovec *vector,
                    unsigned long count, loff_t *ppos);
static ssize_t sock_writev(struct file *file, const struct iovec *vector,
                    unsigned long count, loff_t *ppos);
static ssize_t sock_sendpage(struct file *file, struct page *page,
                       int offset, size_t size, loff_t *ppos, int more);

/*
 *    Socket files have a set of 'special' operations as well as the generic file ones. These don't appear
 *    in the operation structures but are done directly via the socketcall() multiplexor.
 */

static struct file_operations socket_file_ops = {
      .owner =    THIS_MODULE,
      .llseek =   no_llseek,
      .aio_read = sock_aio_read,
      .aio_write =      sock_aio_write,
      .poll =           sock_poll,
      .unlocked_ioctl = sock_ioctl,
#ifdef CONFIG_COMPAT
      .compat_ioctl = compat_sock_ioctl,
#endif
      .mmap =           sock_mmap,
      .open =           sock_no_open,     /* special open code to disallow open via /proc */
      .release =  sock_close,
      .fasync =   sock_fasync,
      .readv =    sock_readv,
      .writev =   sock_writev,
      .sendpage = sock_sendpage,
      .splice_write = generic_splice_sendpage,
};

/*
 *    The protocol list. Each protocol is registered in here.
 */

static struct net_proto_family *net_families[NPROTO];

#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
static atomic_t net_family_lockct = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(net_family_lock);

/* The strategy is: modifications net_family vector are short, do not
   sleep and veeery rare, but read access should be free of any exclusive
   locks.
 */

static void net_family_write_lock(void)
{
      spin_lock(&net_family_lock);
      while (atomic_read(&net_family_lockct) != 0) {
            spin_unlock(&net_family_lock);

            yield();

            spin_lock(&net_family_lock);
      }
}

static __inline__ void net_family_write_unlock(void)
{
      spin_unlock(&net_family_lock);
}

static __inline__ void net_family_read_lock(void)
{
      atomic_inc(&net_family_lockct);
      spin_unlock_wait(&net_family_lock);
}

static __inline__ void net_family_read_unlock(void)
{
      atomic_dec(&net_family_lockct);
}

#else
#define net_family_write_lock() do { } while(0)
#define net_family_write_unlock() do { } while(0)
#define net_family_read_lock() do { } while(0)
#define net_family_read_unlock() do { } while(0)
#endif


/*
 *    Statistics counters of the socket lists
 */

static DEFINE_PER_CPU(int, sockets_in_use) = 0;

/*
 *    Support routines. Move socket addresses back and forth across the kernel/user
 *    divide and look after the messy bits.
 */

#define MAX_SOCK_ADDR   128         /* 108 for Unix domain - 
                                 16 for IP, 16 for IPX,
                                 24 for IPv6,
                                 about 80 for AX.25 
                                 must be at least one bigger than
                                 the AF_UNIX size (see net/unix/af_unix.c
                                 :unix_mkname()).  
                               */
                               
/**
 *    move_addr_to_kernel     -     copy a socket address into kernel space
 *    @uaddr: Address in user space
 *    @kaddr: Address in kernel space
 *    @ulen: Length in user space
 *
 *    The address is copied into kernel space. If the provided address is
 *    too long an error code of -EINVAL is returned. If the copy gives
 *    invalid addresses -EFAULT is returned. On a success 0 is returned.
 */

int move_addr_to_kernel(void __user *uaddr, int ulen, void *kaddr)
{
      if(ulen<0||ulen>MAX_SOCK_ADDR)
            return -EINVAL;
      if(ulen==0)
            return 0;
      if(copy_from_user(kaddr,uaddr,ulen))
            return -EFAULT;
      return audit_sockaddr(ulen, kaddr);
}

/**
 *    move_addr_to_user -     copy an address to user space
 *    @kaddr: kernel space address
 *    @klen: length of address in kernel
 *    @uaddr: user space address
 *    @ulen: pointer to user length field
 *
 *    The value pointed to by ulen on entry is the buffer length available.
 *    This is overwritten with the buffer space used. -EINVAL is returned
 *    if an overlong buffer is specified or a negative buffer size. -EFAULT
 *    is returned if either the buffer or the length field are not
 *    accessible.
 *    After copying the data up to the limit the user specifies, the true
 *    length of the data is written over the length limit the user
 *    specified. Zero is returned for a success.
 */
 
int move_addr_to_user(void *kaddr, int klen, void __user *uaddr, int __user *ulen)
{
      int err;
      int len;

      if((err=get_user(len, ulen)))
            return err;
      if(len>klen)
            len=klen;
      if(len<0 || len> MAX_SOCK_ADDR)
            return -EINVAL;
      if(len)
      {
            if (audit_sockaddr(klen, kaddr))
                  return -ENOMEM;
            if(copy_to_user(uaddr,kaddr,len))
                  return -EFAULT;
      }
      /*
       *    "fromlen shall refer to the value before truncation.."
       *                1003.1g
       */
      return __put_user(klen, ulen);
}

#define SOCKFS_MAGIC 0x534F434B

static kmem_cache_t * sock_inode_cachep __read_mostly;

static struct inode *sock_alloc_inode(struct super_block *sb)
{
      struct socket_alloc *ei;
      ei = (struct socket_alloc *)kmem_cache_alloc(sock_inode_cachep, SLAB_KERNEL);
      if (!ei)
            return NULL;
      init_waitqueue_head(&ei->socket.wait);
      
      ei->socket.fasync_list = NULL;
      ei->socket.state = SS_UNCONNECTED;
      ei->socket.flags = 0;
      ei->socket.ops = NULL;
      ei->socket.sk = NULL;
      ei->socket.file = NULL;
      ei->socket.flags = 0;

      return &ei->vfs_inode;
}

static void sock_destroy_inode(struct inode *inode)
{
      kmem_cache_free(sock_inode_cachep,
                  container_of(inode, struct socket_alloc, vfs_inode));
}

static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
      struct socket_alloc *ei = (struct socket_alloc *) foo;

      if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
          SLAB_CTOR_CONSTRUCTOR)
            inode_init_once(&ei->vfs_inode);
}
 
static int init_inodecache(void)
{
      sock_inode_cachep = kmem_cache_create("sock_inode_cache",
                        sizeof(struct socket_alloc),
                        0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
                              SLAB_MEM_SPREAD),
                        init_once, NULL);
      if (sock_inode_cachep == NULL)
            return -ENOMEM;
      return 0;
}

static struct super_operations sockfs_ops = {
      .alloc_inode =    sock_alloc_inode,
      .destroy_inode =sock_destroy_inode,
      .statfs =   simple_statfs,
};

static int sockfs_get_sb(struct file_system_type *fs_type,
      int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
      return get_sb_pseudo(fs_type, "socket:", &sockfs_ops, SOCKFS_MAGIC,
                       mnt);
}

static struct vfsmount *sock_mnt __read_mostly;

static struct file_system_type sock_fs_type = {
      .name =           "sockfs",
      .get_sb =   sockfs_get_sb,
      .kill_sb =  kill_anon_super,
};
static int sockfs_delete_dentry(struct dentry *dentry)
{
      return 1;
}
static struct dentry_operations sockfs_dentry_operations = {
      .d_delete = sockfs_delete_dentry,
};

/*
 *    Obtains the first available file descriptor and sets it up for use.
 *
 *    These functions create file structures and maps them to fd space
 *    of the current process. On success it returns file descriptor
 *    and file struct implicitly stored in sock->file.
 *    Note that another thread may close file descriptor before we return
 *    from this function. We use the fact that now we do not refer
 *    to socket after mapping. If one day we will need it, this
 *    function will increment ref. count on file by 1.
 *
 *    In any case returned fd MAY BE not valid!
 *    This race condition is unavoidable
 *    with shared fd spaces, we cannot solve it inside kernel,
 *    but we take care of internal coherence yet.
 */

static int sock_alloc_fd(struct file **filep)
{
      int fd;

      fd = get_unused_fd();
      if (likely(fd >= 0)) {
            struct file *file = get_empty_filp();

            *filep = file;
            if (unlikely(!file)) {
                  put_unused_fd(fd);
                  return -ENFILE;
            }
      } else
            *filep = NULL;
      return fd;
}

static int sock_attach_fd(struct socket *sock, struct file *file)
{
      struct qstr this;
      char name[32];

      this.len = sprintf(name, "[%lu]", SOCK_INODE(sock)->i_ino);
      this.name = name;
      this.hash = SOCK_INODE(sock)->i_ino;

      file->f_dentry = d_alloc(sock_mnt->mnt_sb->s_root, &this);
      if (unlikely(!file->f_dentry))
            return -ENOMEM;

      file->f_dentry->d_op = &sockfs_dentry_operations;
      d_add(file->f_dentry, SOCK_INODE(sock));
      file->f_vfsmnt = mntget(sock_mnt);
      file->f_mapping = file->f_dentry->d_inode->i_mapping;

      sock->file = file;
      file->f_op = SOCK_INODE(sock)->i_fop = &socket_file_ops;
      file->f_mode = FMODE_READ | FMODE_WRITE;
      file->f_flags = O_RDWR;
      file->f_pos = 0;
      file->private_data = sock;

      return 0;
}

int sock_map_fd(struct socket *sock)
{
      struct file *newfile;
      int fd = sock_alloc_fd(&newfile);

      if (likely(fd >= 0)) {
            int err = sock_attach_fd(sock, newfile);

            if (unlikely(err < 0)) {
                  put_filp(newfile);
                  put_unused_fd(fd);
                  return err;
            }
            fd_install(fd, newfile);
      }
      return fd;
}

static struct socket *sock_from_file(struct file *file, int *err)
{
      struct inode *inode;
      struct socket *sock;

      if (file->f_op == &socket_file_ops)
            return file->private_data;    /* set in sock_map_fd */

      inode = file->f_dentry->d_inode;
      if (!S_ISSOCK(inode->i_mode)) {
            *err = -ENOTSOCK;
            return NULL;
      }

      sock = SOCKET_I(inode);
      if (sock->file != file) {
            printk(KERN_ERR "socki_lookup: socket file changed!\n");
            sock->file = file;
      }
      return sock;
}

/**
 *    sockfd_lookup     -     Go from a file number to its socket slot
 *    @fd: file handle
 *    @err: pointer to an error code return
 *
 *    The file handle passed in is locked and the socket it is bound
 *    too is returned. If an error occurs the err pointer is overwritten
 *    with a negative errno code and NULL is returned. The function checks
 *    for both invalid handles and passing a handle which is not a socket.
 *
 *    On a success the socket object pointer is returned.
 */

struct socket *sockfd_lookup(int fd, int *err)
{
      struct file *file;
      struct socket *sock;

      if (!(file = fget(fd))) {
            *err = -EBADF;
            return NULL;
      }
      sock = sock_from_file(file, err);
      if (!sock)
            fput(file);
      return sock;
}

static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
{
      struct file *file;
      struct socket *sock;

      *err = -EBADF;
      file = fget_light(fd, fput_needed);
      if (file) {
            sock = sock_from_file(file, err);
            if (sock)
                  return sock;
            fput_light(file, *fput_needed);
      }
      return NULL;
}

/**
 *    sock_alloc  -     allocate a socket
 *    
 *    Allocate a new inode and socket object. The two are bound together
 *    and initialised. The socket is then returned. If we are out of inodes
 *    NULL is returned.
 */

static struct socket *sock_alloc(void)
{
      struct inode * inode;
      struct socket * sock;

      inode = new_inode(sock_mnt->mnt_sb);
      if (!inode)
            return NULL;

      sock = SOCKET_I(inode);

      inode->i_mode = S_IFSOCK|S_IRWXUGO;
      inode->i_uid = current->fsuid;
      inode->i_gid = current->fsgid;

      get_cpu_var(sockets_in_use)++;
      put_cpu_var(sockets_in_use);
      return sock;
}

/*
 *    In theory you can't get an open on this inode, but /proc provides
 *    a back door. Remember to keep it shut otherwise you'll let the
 *    creepy crawlies in.
 */
  
static int sock_no_open(struct inode *irrelevant, struct file *dontcare)
{
      return -ENXIO;
}

const struct file_operations bad_sock_fops = {
      .owner = THIS_MODULE,
      .open = sock_no_open,
};

/**
 *    sock_release      -     close a socket
 *    @sock: socket to close
 *
 *    The socket is released from the protocol stack if it has a release
 *    callback, and the inode is then released if the socket is bound to
 *    an inode not a file. 
 */
 
void sock_release(struct socket *sock)
{
      if (sock->ops) {
            struct module *owner = sock->ops->owner;

            sock->ops->release(sock);
            sock->ops = NULL;
            module_put(owner);
      }

      if (sock->fasync_list)
            printk(KERN_ERR "sock_release: fasync list not empty!\n");

      get_cpu_var(sockets_in_use)--;
      put_cpu_var(sockets_in_use);
      if (!sock->file) {
            iput(SOCK_INODE(sock));
            return;
      }
      sock->file=NULL;
}

static inline int __sock_sendmsg(struct kiocb *iocb, struct socket *sock, 
                         struct msghdr *msg, size_t size)
{
      struct sock_iocb *si = kiocb_to_siocb(iocb);
      int err;

      si->sock = sock;
      si->scm = NULL;
      si->msg = msg;
      si->size = size;

      err = security_socket_sendmsg(sock, msg, size);
      if (err)
            return err;

      return sock->ops->sendmsg(iocb, sock, msg, size);
}

int sock_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
{
      struct kiocb iocb;
      struct sock_iocb siocb;
      int ret;

      init_sync_kiocb(&iocb, NULL);
      iocb.private = &siocb;
      ret = __sock_sendmsg(&iocb, sock, msg, size);
      if (-EIOCBQUEUED == ret)
            ret = wait_on_sync_kiocb(&iocb);
      return ret;
}

int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
               struct kvec *vec, size_t num, size_t size)
{
      mm_segment_t oldfs = get_fs();
      int result;

      set_fs(KERNEL_DS);
      /*
       * the following is safe, since for compiler definitions of kvec and
       * iovec are identical, yielding the same in-core layout and alignment
       */
      msg->msg_iov = (struct iovec *)vec,
      msg->msg_iovlen = num;
      result = sock_sendmsg(sock, msg, size);
      set_fs(oldfs);
      return result;
}

static inline int __sock_recvmsg(struct kiocb *iocb, struct socket *sock, 
                         struct msghdr *msg, size_t size, int flags)
{
      int err;
      struct sock_iocb *si = kiocb_to_siocb(iocb);

      si->sock = sock;
      si->scm = NULL;
      si->msg = msg;
      si->size = size;
      si->flags = flags;

      err = security_socket_recvmsg(sock, msg, size, flags);
      if (err)
            return err;

      return sock->ops->recvmsg(iocb, sock, msg, size, flags);
}

int sock_recvmsg(struct socket *sock, struct msghdr *msg, 
             size_t size, int flags)
{
      struct kiocb iocb;
      struct sock_iocb siocb;
      int ret;

        init_sync_kiocb(&iocb, NULL);
      iocb.private = &siocb;
      ret = __sock_recvmsg(&iocb, sock, msg, size, flags);
      if (-EIOCBQUEUED == ret)
            ret = wait_on_sync_kiocb(&iocb);
      return ret;
}

int kernel_recvmsg(struct socket *sock, struct msghdr *msg, 
               struct kvec *vec, size_t num,
               size_t size, int flags)
{
      mm_segment_t oldfs = get_fs();
      int result;

      set_fs(KERNEL_DS);
      /*
       * the following is safe, since for compiler definitions of kvec and
       * iovec are identical, yielding the same in-core layout and alignment
       */
      msg->msg_iov = (struct iovec *)vec,
      msg->msg_iovlen = num;
      result = sock_recvmsg(sock, msg, size, flags);
      set_fs(oldfs);
      return result;
}

static void sock_aio_dtor(struct kiocb *iocb)
{
      kfree(iocb->private);
}

static ssize_t sock_sendpage(struct file *file, struct page *page,
                       int offset, size_t size, loff_t *ppos, int more)
{
      struct socket *sock;
      int flags;

      sock = file->private_data;

      flags = !(file->f_flags & O_NONBLOCK) ? 0 : MSG_DONTWAIT;
      if (more)
            flags |= MSG_MORE;

      return sock->ops->sendpage(sock, page, offset, size, flags);
}

static struct sock_iocb *alloc_sock_iocb(struct kiocb *iocb,
            char __user *ubuf, size_t size, struct sock_iocb *siocb)
{
      if (!is_sync_kiocb(iocb)) {
            siocb = kmalloc(sizeof(*siocb), GFP_KERNEL);
            if (!siocb)
                  return NULL;
            iocb->ki_dtor = sock_aio_dtor;
      }

      siocb->kiocb = iocb;
      siocb->async_iov.iov_base = ubuf;
      siocb->async_iov.iov_len = size;

      iocb->private = siocb;
      return siocb;
}

static ssize_t do_sock_read(struct msghdr *msg, struct kiocb *iocb,
            struct file *file, struct iovec *iov, unsigned long nr_segs)
{
      struct socket *sock = file->private_data;
      size_t size = 0;
      int i;

        for (i = 0 ; i < nr_segs ; i++)
                size += iov[i].iov_len;

      msg->msg_name = NULL;
      msg->msg_namelen = 0;
      msg->msg_control = NULL;
      msg->msg_controllen = 0;
      msg->msg_iov = (struct iovec *) iov;
      msg->msg_iovlen = nr_segs;
      msg->msg_flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0;

      return __sock_recvmsg(iocb, sock, msg, size, msg->msg_flags);
}

static ssize_t sock_readv(struct file *file, const struct iovec *iov,
                    unsigned long nr_segs, loff_t *ppos)
{
      struct kiocb iocb;
      struct sock_iocb siocb;
      struct msghdr msg;
      int ret;

        init_sync_kiocb(&iocb, NULL);
      iocb.private = &siocb;

      ret = do_sock_read(&msg, &iocb, file, (struct iovec *)iov, nr_segs);
      if (-EIOCBQUEUED == ret)
            ret = wait_on_sync_kiocb(&iocb);
      return ret;
}

static ssize_t sock_aio_read(struct kiocb *iocb, char __user *ubuf,
                   size_t count, loff_t pos)
{
      struct sock_iocb siocb, *x;

      if (pos != 0)
            return -ESPIPE;
      if (count == 0)         /* Match SYS5 behaviour */
            return 0;

      x = alloc_sock_iocb(iocb, ubuf, count, &siocb);
      if (!x)
            return -ENOMEM;
      return do_sock_read(&x->async_msg, iocb, iocb->ki_filp,
                  &x->async_iov, 1);
}

static ssize_t do_sock_write(struct msghdr *msg, struct kiocb *iocb,
            struct file *file, struct iovec *iov, unsigned long nr_segs)
{
      struct socket *sock = file->private_data;
      size_t size = 0;
      int i;

        for (i = 0 ; i < nr_segs ; i++)
                size += iov[i].iov_len;

      msg->msg_name = NULL;
      msg->msg_namelen = 0;
      msg->msg_control = NULL;
      msg->msg_controllen = 0;
      msg->msg_iov = (struct iovec *) iov;
      msg->msg_iovlen = nr_segs;
      msg->msg_flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0;
      if (sock->type == SOCK_SEQPACKET)
            msg->msg_flags |= MSG_EOR;

      return __sock_sendmsg(iocb, sock, msg, size);
}

static ssize_t sock_writev(struct file *file, const struct iovec *iov,
                     unsigned long nr_segs, loff_t *ppos)
{
      struct msghdr msg;
      struct kiocb iocb;
      struct sock_iocb siocb;
      int ret;

      init_sync_kiocb(&iocb, NULL);
      iocb.private = &siocb;

      ret = do_sock_write(&msg, &iocb, file, (struct iovec *)iov, nr_segs);
      if (-EIOCBQUEUED == ret)
            ret = wait_on_sync_kiocb(&iocb);
      return ret;
}

static ssize_t sock_aio_write(struct kiocb *iocb, const char __user *ubuf,
                    size_t count, loff_t pos)
{
      struct sock_iocb siocb, *x;

      if (pos != 0)
            return -ESPIPE;
      if (count == 0)         /* Match SYS5 behaviour */
            return 0;

      x = alloc_sock_iocb(iocb, (void __user *)ubuf, count, &siocb);
      if (!x)
            return -ENOMEM;

      return do_sock_write(&x->async_msg, iocb, iocb->ki_filp,
                  &x->async_iov, 1);
}


/*
 * Atomic setting of ioctl hooks to avoid race
 * with module unload.
 */

static DEFINE_MUTEX(br_ioctl_mutex);
static int (*br_ioctl_hook)(unsigned int cmd, void __user *arg) = NULL;

void brioctl_set(int (*hook)(unsigned int, void __user *))
{
      mutex_lock(&br_ioctl_mutex);
      br_ioctl_hook = hook;
      mutex_unlock(&br_ioctl_mutex);
}
EXPORT_SYMBOL(brioctl_set);

static DEFINE_MUTEX(vlan_ioctl_mutex);
static int (*vlan_ioctl_hook)(void __user *arg);

void vlan_ioctl_set(int (*hook)(void __user *))
{
      mutex_lock(&vlan_ioctl_mutex);
      vlan_ioctl_hook = hook;
      mutex_unlock(&vlan_ioctl_mutex);
}
EXPORT_SYMBOL(vlan_ioctl_set);

static DEFINE_MUTEX(dlci_ioctl_mutex);
static int (*dlci_ioctl_hook)(unsigned int, void __user *);

void dlci_ioctl_set(int (*hook)(unsigned int, void __user *))
{
      mutex_lock(&dlci_ioctl_mutex);
      dlci_ioctl_hook = hook;
      mutex_unlock(&dlci_ioctl_mutex);
}
EXPORT_SYMBOL(dlci_ioctl_set);

/*
 *    With an ioctl, arg may well be a user mode pointer, but we don't know
 *    what to do with it - that's up to the protocol still.
 */

static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
      struct socket *sock;
      void __user *argp = (void __user *)arg;
      int pid, err;

      sock = file->private_data;
      if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {
            err = dev_ioctl(cmd, argp);
      } else
#ifdef CONFIG_WIRELESS_EXT
      if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {
            err = dev_ioctl(cmd, argp);
      } else
#endif      /* CONFIG_WIRELESS_EXT */
      switch (cmd) {
            case FIOSETOWN:
            case SIOCSPGRP:
                  err = -EFAULT;
                  if (get_user(pid, (int __user *)argp))
                        break;
                  err = f_setown(sock->file, pid, 1);
                  break;
            case FIOGETOWN:
            case SIOCGPGRP:
                  err = put_user(sock->file->f_owner.pid, (int __user *)argp);
                  break;
            case SIOCGIFBR:
            case SIOCSIFBR:
            case SIOCBRADDBR:
            case SIOCBRDELBR:
                  err = -ENOPKG;
                  if (!br_ioctl_hook)
                        request_module("bridge");

                  mutex_lock(&br_ioctl_mutex);
                  if (br_ioctl_hook) 
                        err = br_ioctl_hook(cmd, argp);
                  mutex_unlock(&br_ioctl_mutex);
                  break;
            case SIOCGIFVLAN:
            case SIOCSIFVLAN:
                  err = -ENOPKG;
                  if (!vlan_ioctl_hook)
                        request_module("8021q");

                  mutex_lock(&vlan_ioctl_mutex);
                  if (vlan_ioctl_hook)
                        err = vlan_ioctl_hook(argp);
                  mutex_unlock(&vlan_ioctl_mutex);
                  break;
            case SIOCGIFDIVERT:
            case SIOCSIFDIVERT:
            /* Convert this to call through a hook */
                  err = divert_ioctl(cmd, argp);
                  break;
            case SIOCADDDLCI:
            case SIOCDELDLCI:
                  err = -ENOPKG;
                  if (!dlci_ioctl_hook)
                        request_module("dlci");

                  if (dlci_ioctl_hook) {
                        mutex_lock(&dlci_ioctl_mutex);
                        err = dlci_ioctl_hook(cmd, argp);
                        mutex_unlock(&dlci_ioctl_mutex);
                  }
                  break;
            default:
                  err = sock->ops->ioctl(sock, cmd, arg);

                  /*
                   * If this ioctl is unknown try to hand it down
                   * to the NIC driver.
                   */
                  if (err == -ENOIOCTLCMD)
                        err = dev_ioctl(cmd, argp);
                  break;
      }
      return err;
}

int sock_create_lite(int family, int type, int protocol, struct socket **res)
{
      int err;
      struct socket *sock = NULL;
      
      err = security_socket_create(family, type, protocol, 1);
      if (err)
            goto out;

      sock = sock_alloc();
      if (!sock) {
            err = -ENOMEM;
            goto out;
      }

      security_socket_post_create(sock, family, type, protocol, 1);
      sock->type = type;
out:
      *res = sock;
      return err;
}

/* No kernel lock held - perfect */
static unsigned int sock_poll(struct file *file, poll_table * wait)
{
      struct socket *sock;

      /*
       *    We can't return errors to poll, so it's either yes or no. 
       */
      sock = file->private_data;
      return sock->ops->poll(file, sock, wait);
}

static int sock_mmap(struct file * file, struct vm_area_struct * vma)
{
      struct socket *sock = file->private_data;

      return sock->ops->mmap(file, sock, vma);
}

static int sock_close(struct inode *inode, struct file *filp)
{
      /*
       *    It was possible the inode is NULL we were 
       *    closing an unfinished socket. 
       */

      if (!inode)
      {
            printk(KERN_DEBUG "sock_close: NULL inode\n");
            return 0;
      }
      sock_fasync(-1, filp, 0);
      sock_release(SOCKET_I(inode));
      return 0;
}

/*
 *    Update the socket async list
 *
 *    Fasync_list locking strategy.
 *
 *    1. fasync_list is modified only under process context socket lock
 *       i.e. under semaphore.
 *    2. fasync_list is used under read_lock(&sk->sk_callback_lock)
 *       or under socket lock.
 *    3. fasync_list can be used from softirq context, so that
 *       modification under socket lock have to be enhanced with
 *       write_lock_bh(&sk->sk_callback_lock).
 *                                        --ANK (990710)
 */

static int sock_fasync(int fd, struct file *filp, int on)
{
      struct fasync_struct *fa, *fna=NULL, **prev;
      struct socket *sock;
      struct sock *sk;

      if (on)
      {
            fna = kmalloc(sizeof(struct fasync_struct), GFP_KERNEL);
            if(fna==NULL)
                  return -ENOMEM;
      }

      sock = filp->private_data;

      if ((sk=sock->sk) == NULL) {
            kfree(fna);
            return -EINVAL;
      }

      lock_sock(sk);

      prev=&(sock->fasync_list);

      for (fa=*prev; fa!=NULL; prev=&fa->fa_next,fa=*prev)
            if (fa->fa_file==filp)
                  break;

      if(on)
      {
            if(fa!=NULL)
            {
                  write_lock_bh(&sk->sk_callback_lock);
                  fa->fa_fd=fd;
                  write_unlock_bh(&sk->sk_callback_lock);

                  kfree(fna);
                  goto out;
            }
            fna->fa_file=filp;
            fna->fa_fd=fd;
            fna->magic=FASYNC_MAGIC;
            fna->fa_next=sock->fasync_list;
            write_lock_bh(&sk->sk_callback_lock);
            sock->fasync_list=fna;
            write_unlock_bh(&sk->sk_callback_lock);
      }
      else
      {
            if (fa!=NULL)
            {
                  write_lock_bh(&sk->sk_callback_lock);
                  *prev=fa->fa_next;
                  write_unlock_bh(&sk->sk_callback_lock);
                  kfree(fa);
            }
      }

out:
      release_sock(sock->sk);
      return 0;
}

/* This function may be called only under socket lock or callback_lock */

int sock_wake_async(struct socket *sock, int how, int band)
{
      if (!sock || !sock->fasync_list)
            return -1;
      switch (how)
      {
      case 1:
            
            if (test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
                  break;
            goto call_kill;
      case 2:
            if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags))
                  break;
            /* fall through */
      case 0:
      call_kill:
            __kill_fasync(sock->fasync_list, SIGIO, band);
            break;
      case 3:
            __kill_fasync(sock->fasync_list, SIGURG, band);
      }
      return 0;
}

static int __sock_create(int family, int type, int protocol, struct socket **res, int kern)
{
      int err;
      struct socket *sock;

      /*
       *    Check protocol is in range
       */
      if (family < 0 || family >= NPROTO)
            return -EAFNOSUPPORT;
      if (type < 0 || type >= SOCK_MAX)
            return -EINVAL;

      /* Compatibility.

         This uglymoron is moved from INET layer to here to avoid
         deadlock in module load.
       */
      if (family == PF_INET && type == SOCK_PACKET) {
            static int warned; 
            if (!warned) {
                  warned = 1;
                  printk(KERN_INFO "%s uses obsolete (PF_INET,SOCK_PACKET)\n", current->comm);
            }
            family = PF_PACKET;
      }

      err = security_socket_create(family, type, protocol, kern);
      if (err)
            return err;
            
#if defined(CONFIG_KMOD)
      /* Attempt to load a protocol module if the find failed. 
       * 
       * 12/09/1996 Marcin: But! this makes REALLY only sense, if the user 
       * requested real, full-featured networking support upon configuration.
       * Otherwise module support will break!
       */
      if (net_families[family]==NULL)
      {
            request_module("net-pf-%d",family);
      }
#endif

      net_family_read_lock();
      if (net_families[family] == NULL) {
            err = -EAFNOSUPPORT;
            goto out;
      }

/*
 *    Allocate the socket and allow the family to set things up. if
 *    the protocol is 0, the family is instructed to select an appropriate
 *    default.
 */

      if (!(sock = sock_alloc())) {
            if (net_ratelimit())
                  printk(KERN_WARNING "socket: no more sockets\n");
            err = -ENFILE;          /* Not exactly a match, but its the
                                 closest posix thing */
            goto out;
      }

      sock->type  = type;

      /*
       * We will call the ->create function, that possibly is in a loadable
       * module, so we have to bump that loadable module refcnt first.
       */
      err = -EAFNOSUPPORT;
      if (!try_module_get(net_families[family]->owner))
            goto out_release;

      if ((err = net_families[family]->create(sock, protocol)) < 0) {
            sock->ops = NULL;
            goto out_module_put;
      }

      /*
       * Now to bump the refcnt of the [loadable] module that owns this
       * socket at sock_release time we decrement its refcnt.
       */
      if (!try_module_get(sock->ops->owner)) {
            sock->ops = NULL;
            goto out_module_put;
      }
      /*
       * Now that we're done with the ->create function, the [loadable]
       * module can have its refcnt decremented
       */
      module_put(net_families[family]->owner);
      *res = sock;
      security_socket_post_create(sock, family, type, protocol, kern);

out:
      net_family_read_unlock();
      return err;
out_module_put:
      module_put(net_families[family]->owner);
out_release:
      sock_release(sock);
      goto out;
}

int sock_create(int family, int type, int protocol, struct socket **res)
{
      return __sock_create(family, type, protocol, res, 0);
}

int sock_create_kern(int family, int type, int protocol, struct socket **res)
{
      return __sock_create(family, type, protocol, res, 1);
}

asmlinkage long sys_socket(int family, int type, int protocol)
{
      int retval;
      struct socket *sock;

      retval = sock_create(family, type, protocol, &sock);
      if (retval < 0)
            goto out;

      retval = sock_map_fd(sock);
      if (retval < 0)
            goto out_release;

out:
      /* It may be already another descriptor 8) Not kernel problem. */
      return retval;

out_release:
      sock_release(sock);
      return retval;
}

/*
 *    Create a pair of connected sockets.
 */

asmlinkage long sys_socketpair(int family, int type, int protocol, int __user *usockvec)
{
      struct socket *sock1, *sock2;
      int fd1, fd2, err;

      /*
       * Obtain the first socket and check if the underlying protocol
       * supports the socketpair call.
       */

      err = sock_create(family, type, protocol, &sock1);
      if (err < 0)
            goto out;

      err = sock_create(family, type, protocol, &sock2);
      if (err < 0)
            goto out_release_1;

      err = sock1->ops->socketpair(sock1, sock2);
      if (err < 0) 
            goto out_release_both;

      fd1 = fd2 = -1;

      err = sock_map_fd(sock1);
      if (err < 0)
            goto out_release_both;
      fd1 = err;

      err = sock_map_fd(sock2);
      if (err < 0)
            goto out_close_1;
      fd2 = err;

      /* fd1 and fd2 may be already another descriptors.
       * Not kernel problem.
       */

      err = put_user(fd1, &usockvec[0]); 
      if (!err)
            err = put_user(fd2, &usockvec[1]);
      if (!err)
            return 0;

      sys_close(fd2);
      sys_close(fd1);
      return err;

out_close_1:
        sock_release(sock2);
      sys_close(fd1);
      return err;

out_release_both:
        sock_release(sock2);
out_release_1:
        sock_release(sock1);
out:
      return err;
}


/*
 *    Bind a name to a socket. Nothing much to do here since it's
 *    the protocol's responsibility to handle the local address.
 *
 *    We move the socket address to kernel space before we call
 *    the protocol layer (having also checked the address is ok).
 */

asmlinkage long sys_bind(int fd, struct sockaddr __user *umyaddr, int addrlen)
{
      struct socket *sock;
      char address[MAX_SOCK_ADDR];
      int err, fput_needed;

      if((sock = sockfd_lookup_light(fd, &err, &fput_needed))!=NULL)
      {
            if((err=move_addr_to_kernel(umyaddr,addrlen,address))>=0) {
                  err = security_socket_bind(sock, (struct sockaddr *)address, addrlen);
                  if (!err)
                        err = sock->ops->bind(sock,
                              (struct sockaddr *)address, addrlen);
            }
            fput_light(sock->file, fput_needed);
      }                 
      return err;
}


/*
 *    Perform a listen. Basically, we allow the protocol to do anything
 *    necessary for a listen, and if that works, we mark the socket as
 *    ready for listening.
 */

int sysctl_somaxconn = SOMAXCONN;

asmlinkage long sys_listen(int fd, int backlog)
{
      struct socket *sock;
      int err, fput_needed;
      
      if ((sock = sockfd_lookup_light(fd, &err, &fput_needed)) != NULL) {
            if ((unsigned) backlog > sysctl_somaxconn)
                  backlog = sysctl_somaxconn;

            err = security_socket_listen(sock, backlog);
            if (!err)
                  err = sock->ops->listen(sock, backlog);

            fput_light(sock->file, fput_needed);
      }
      return err;
}


/*
 *    For accept, we attempt to create a new socket, set up the link
 *    with the client, wake up the client, then return the new
 *    connected fd. We collect the address of the connector in kernel
 *    space and move it to user at the very end. This is unclean because
 *    we open the socket then return an error.
 *
 *    1003.1g adds the ability to recvmsg() to query connection pending
 *    status to recvmsg. We need to add that support in a way thats
 *    clean when we restucture accept also.
 */

asmlinkage long sys_accept(int fd, struct sockaddr __user *upeer_sockaddr, int __user *upeer_addrlen)
{
      struct socket *sock, *newsock;
      struct file *newfile;
      int err, len, newfd, fput_needed;
      char address[MAX_SOCK_ADDR];

      sock = sockfd_lookup_light(fd, &err, &fput_needed);
      if (!sock)
            goto out;

      err = -ENFILE;
      if (!(newsock = sock_alloc())) 
            goto out_put;

      newsock->type = sock->type;
      newsock->ops = sock->ops;

      /*
       * We don't need try_module_get here, as the listening socket (sock)
       * has the protocol module (sock->ops->owner) held.
       */
      __module_get(newsock->ops->owner);

      newfd = sock_alloc_fd(&newfile);
      if (unlikely(newfd < 0)) {
            err = newfd;
            sock_release(newsock);
            goto out_put;
      }

      err = sock_attach_fd(newsock, newfile);
      if (err < 0)
            goto out_fd;

      err = security_socket_accept(sock, newsock);
      if (err)
            goto out_fd;

      err = sock->ops->accept(sock, newsock, sock->file->f_flags);
      if (err < 0)
            goto out_fd;

      if (upeer_sockaddr) {
            if(newsock->ops->getname(newsock, (struct sockaddr *)address, &len, 2)<0) {
                  err = -ECONNABORTED;
                  goto out_fd;
            }
            err = move_addr_to_user(address, len, upeer_sockaddr, upeer_addrlen);
            if (err < 0)
                  goto out_fd;
      }

      /* File flags are not inherited via accept() unlike another OSes. */

      fd_install(newfd, newfile);
      err = newfd;

      security_socket_post_accept(sock, newsock);

out_put:
      fput_light(sock->file, fput_needed);
out:
      return err;
out_fd:
      fput(newfile);
      put_unused_fd(newfd);
      goto out_put;
}


/*
 *    Attempt to connect to a socket with the server address.  The address
 *    is in user space so we verify it is OK and move it to kernel space.
 *
 *    For 1003.1g we need to add clean support for a bind to AF_UNSPEC to
 *    break bindings
 *
 *    NOTE: 1003.1g draft 6.3 is broken with respect to AX.25/NetROM and
 *    other SEQPACKET protocols that take time to connect() as it doesn't
 *    include the -EINPROGRESS status for such sockets.
 */

asmlinkage long sys_connect(int fd, struct sockaddr __user *uservaddr, int addrlen)
{
      struct socket *sock;
      char address[MAX_SOCK_ADDR];
      int err, fput_needed;

      sock = sockfd_lookup_light(fd, &err, &fput_needed);
      if (!sock)
            goto out;
      err = move_addr_to_kernel(uservaddr, addrlen, address);
      if (err < 0)
            goto out_put;

      err = security_socket_connect(sock, (struct sockaddr *)address, addrlen);
      if (err)
            goto out_put;

      err = sock->ops->connect(sock, (struct sockaddr *) address, addrlen,
                         sock->file->f_flags);
out_put:
      fput_light(sock->file, fput_needed);
out:
      return err;
}

/*
 *    Get the local address ('name') of a socket object. Move the obtained
 *    name to user space.
 */

asmlinkage long sys_getsockname(int fd, struct sockaddr __user *usockaddr, int __user *usockaddr_len)
{
      struct socket *sock;
      char address[MAX_SOCK_ADDR];
      int len, err, fput_needed;
      
      sock = sockfd_lookup_light(fd, &err, &fput_needed);
      if (!sock)
            goto out;

      err = security_socket_getsockname(sock);
      if (err)
            goto out_put;

      err = sock->ops->getname(sock, (struct sockaddr *)address, &len, 0);
      if (err)
            goto out_put;
      err = move_addr_to_user(address, len, usockaddr, usockaddr_len);

out_put:
      fput_light(sock->file, fput_needed);
out:
      return err;
}

/*
 *    Get the remote address ('name') of a socket object. Move the obtained
 *    name to user space.
 */

asmlinkage long sys_getpeername(int fd, struct sockaddr __user *usockaddr, int __user *usockaddr_len)
{
      struct socket *sock;
      char address[MAX_SOCK_ADDR];
      int len, err, fput_needed;

      if ((sock = sockfd_lookup_light(fd, &err, &fput_needed)) != NULL) {
            err = security_socket_getpeername(sock);
            if (err) {
                  fput_light(sock->file, fput_needed);
                  return err;
            }

            err = sock->ops->getname(sock, (struct sockaddr *)address, &len, 1);
            if (!err)
                  err=move_addr_to_user(address,len, usockaddr, usockaddr_len);
            fput_light(sock->file, fput_needed);
      }
      return err;
}

/*
 *    Send a datagram to a given address. We move the address into kernel
 *    space and check the user space data area is readable before invoking
 *    the protocol.
 */

asmlinkage long sys_sendto(int fd, void __user * buff, size_t len, unsigned flags,
                     struct sockaddr __user *addr, int addr_len)
{
      struct socket *sock;
      char address[MAX_SOCK_ADDR];
      int err;
      struct msghdr msg;
      struct iovec iov;
      int fput_needed;
      struct file *sock_file;

      sock_file = fget_light(fd, &fput_needed);
      if (!sock_file)
            return -EBADF;

      sock = sock_from_file(sock_file, &err);
      if (!sock)
            goto out_put;
      iov.iov_base=buff;
      iov.iov_len=len;
      msg.msg_name=NULL;
      msg.msg_iov=&iov;
      msg.msg_iovlen=1;
      msg.msg_control=NULL;
      msg.msg_controllen=0;
      msg.msg_namelen=0;
      if (addr) {
            err = move_addr_to_kernel(addr, addr_len, address);
            if (err < 0)
                  goto out_put;
            msg.msg_name=address;
            msg.msg_namelen=addr_len;
      }
      if (sock->file->f_flags & O_NONBLOCK)
            flags |= MSG_DONTWAIT;
      msg.msg_flags = flags;
      err = sock_sendmsg(sock, &msg, len);

out_put:          
      fput_light(sock_file, fput_needed);
      return err;
}

/*
 *    Send a datagram down a socket. 
 */

asmlinkage long sys_send(int fd, void __user * buff, size_t len, unsigned flags)
{
      return sys_sendto(fd, buff, len, flags, NULL, 0);
}

/*
 *    Receive a frame from the socket and optionally record the address of the 
 *    sender. We verify the buffers are writable and if needed move the
 *    sender address from kernel to user space.
 */

asmlinkage long sys_recvfrom(int fd, void __user * ubuf, size_t size, unsigned flags,
                       struct sockaddr __user *addr, int __user *addr_len)
{
      struct socket *sock;
      struct iovec iov;
      struct msghdr msg;
      char address[MAX_SOCK_ADDR];
      int err,err2;
      struct file *sock_file;
      int fput_needed;

      sock_file = fget_light(fd, &fput_needed);
      if (!sock_file)
            return -EBADF;

      sock = sock_from_file(sock_file, &err);
      if (!sock)
            goto out;

      msg.msg_control=NULL;
      msg.msg_controllen=0;
      msg.msg_iovlen=1;
      msg.msg_iov=&iov;
      iov.iov_len=size;
      iov.iov_base=ubuf;
      msg.msg_name=address;
      msg.msg_namelen=MAX_SOCK_ADDR;
      if (sock->file->f_flags & O_NONBLOCK)
            flags |= MSG_DONTWAIT;
      err=sock_recvmsg(sock, &msg, size, flags);

      if(err >= 0 && addr != NULL)
      {
            err2=move_addr_to_user(address, msg.msg_namelen, addr, addr_len);
            if(err2<0)
                  err=err2;
      }
out:
      fput_light(sock_file, fput_needed);
      return err;
}

/*
 *    Receive a datagram from a socket. 
 */

asmlinkage long sys_recv(int fd, void __user * ubuf, size_t size, unsigned flags)
{
      return sys_recvfrom(fd, ubuf, size, flags, NULL, NULL);
}

/*
 *    Set a socket option. Because we don't know the option lengths we have
 *    to pass the user mode parameter for the protocols to sort out.
 */

asmlinkage long sys_setsockopt(int fd, int level, int optname, char __user *optval, int optlen)
{
      int err, fput_needed;
      struct socket *sock;

      if (optlen < 0)
            return -EINVAL;
                  
      if ((sock = sockfd_lookup_light(fd, &err, &fput_needed)) != NULL)
      {
            err = security_socket_setsockopt(sock,level,optname);
            if (err)
                  goto out_put;

            if (level == SOL_SOCKET)
                  err=sock_setsockopt(sock,level,optname,optval,optlen);
            else
                  err=sock->ops->setsockopt(sock, level, optname, optval, optlen);
out_put:
            fput_light(sock->file, fput_needed);
      }
      return err;
}

/*
 *    Get a socket option. Because we don't know the option lengths we have
 *    to pass a user mode parameter for the protocols to sort out.
 */

asmlinkage long sys_getsockopt(int fd, int level, int optname, char __user *optval, int __user *optlen)
{
      int err, fput_needed;
      struct socket *sock;

      if ((sock = sockfd_lookup_light(fd, &err, &fput_needed)) != NULL) {
            err = security_socket_getsockopt(sock, level, optname);
            if (err)
                  goto out_put;

            if (level == SOL_SOCKET)
                  err=sock_getsockopt(sock,level,optname,optval,optlen);
            else
                  err=sock->ops->getsockopt(sock, level, optname, optval, optlen);
out_put:
            fput_light(sock->file, fput_needed);
      }
      return err;
}


/*
 *    Shutdown a socket.
 */

asmlinkage long sys_shutdown(int fd, int how)
{
      int err, fput_needed;
      struct socket *sock;

      if ((sock = sockfd_lookup_light(fd, &err, &fput_needed))!=NULL)
      {
            err = security_socket_shutdown(sock, how);
            if (!err)
                  err = sock->ops->shutdown(sock, how);
            fput_light(sock->file, fput_needed);
      }
      return err;
}

/* A couple of helpful macros for getting the address of the 32/64 bit 
 * fields which are the same type (int / unsigned) on our platforms.
 */
#define COMPAT_MSG(msg, member)     ((MSG_CMSG_COMPAT & flags) ? &msg##_compat->member : &msg->member)
#define COMPAT_NAMELEN(msg)   COMPAT_MSG(msg, msg_namelen)
#define COMPAT_FLAGS(msg)     COMPAT_MSG(msg, msg_flags)


/*
 *    BSD sendmsg interface
 */

asmlinkage long sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags)
{
      struct compat_msghdr __user *msg_compat = (struct compat_msghdr __user *)msg;
      struct socket *sock;
      char address[MAX_SOCK_ADDR];
      struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
      unsigned char ctl[sizeof(struct cmsghdr) + 20]
                  __attribute__ ((aligned (sizeof(__kernel_size_t))));
                  /* 20 is size of ipv6_pktinfo */
      unsigned char *ctl_buf = ctl;
      struct msghdr msg_sys;
      int err, ctl_len, iov_size, total_len;
      int fput_needed;
      
      err = -EFAULT;
      if (MSG_CMSG_COMPAT & flags) {
            if (get_compat_msghdr(&msg_sys, msg_compat))
                  return -EFAULT;
      } else if (copy_from_user(&msg_sys, msg, sizeof(struct msghdr)))
            return -EFAULT;

      sock = sockfd_lookup_light(fd, &err, &fput_needed);
      if (!sock) 
            goto out;

      /* do not move before msg_sys is valid */
      err = -EMSGSIZE;
      if (msg_sys.msg_iovlen > UIO_MAXIOV)
            goto out_put;

      /* Check whether to allocate the iovec area*/
      err = -ENOMEM;
      iov_size = msg_sys.msg_iovlen * sizeof(struct iovec);
      if (msg_sys.msg_iovlen > UIO_FASTIOV) {
            iov = sock_kmalloc(sock->sk, iov_size, GFP_KERNEL);
            if (!iov)
                  goto out_put;
      }

      /* This will also move the address data into kernel space */
      if (MSG_CMSG_COMPAT & flags) {
            err = verify_compat_iovec(&msg_sys, iov, address, VERIFY_READ);
      } else
            err = verify_iovec(&msg_sys, iov, address, VERIFY_READ);
      if (err < 0) 
            goto out_freeiov;
      total_len = err;

      err = -ENOBUFS;

      if (msg_sys.msg_controllen > INT_MAX)
            goto out_freeiov;
      ctl_len = msg_sys.msg_controllen; 
      if ((MSG_CMSG_COMPAT & flags) && ctl_len) {
            err = cmsghdr_from_user_compat_to_kern(&msg_sys, sock->sk, ctl, sizeof(ctl));
            if (err)
                  goto out_freeiov;
            ctl_buf = msg_sys.msg_control;
            ctl_len = msg_sys.msg_controllen;
      } else if (ctl_len) {
            if (ctl_len > sizeof(ctl))
            {
                  ctl_buf = sock_kmalloc(sock->sk, ctl_len, GFP_KERNEL);
                  if (ctl_buf == NULL) 
                        goto out_freeiov;
            }
            err = -EFAULT;
            /*
             * Careful! Before this, msg_sys.msg_control contains a user pointer.
             * Afterwards, it will be a kernel pointer. Thus the compiler-assisted
             * checking falls down on this.
             */
            if (copy_from_user(ctl_buf, (void __user *) msg_sys.msg_control, ctl_len))
                  goto out_freectl;
            msg_sys.msg_control = ctl_buf;
      }
      msg_sys.msg_flags = flags;

      if (sock->file->f_flags & O_NONBLOCK)
            msg_sys.msg_flags |= MSG_DONTWAIT;
      err = sock_sendmsg(sock, &msg_sys, total_len);

out_freectl:
      if (ctl_buf != ctl)    
            sock_kfree_s(sock->sk, ctl_buf, ctl_len);
out_freeiov:
      if (iov != iovstack)
            sock_kfree_s(sock->sk, iov, iov_size);
out_put:
      fput_light(sock->file, fput_needed);
out:       
      return err;
}

/*
 *    BSD recvmsg interface
 */

asmlinkage long sys_recvmsg(int fd, struct msghdr __user *msg, unsigned int flags)
{
      struct compat_msghdr __user *msg_compat = (struct compat_msghdr __user *)msg;
      struct socket *sock;
      struct iovec iovstack[UIO_FASTIOV];
      struct iovec *iov=iovstack;
      struct msghdr msg_sys;
      unsigned long cmsg_ptr;
      int err, iov_size, total_len, len;
      int fput_needed;

      /* kernel mode address */
      char addr[MAX_SOCK_ADDR];

      /* user mode address pointers */
      struct sockaddr __user *uaddr;
      int __user *uaddr_len;
      
      if (MSG_CMSG_COMPAT & flags) {
            if (get_compat_msghdr(&msg_sys, msg_compat))
                  return -EFAULT;
      } else
            if (copy_from_user(&msg_sys,msg,sizeof(struct msghdr)))
                  return -EFAULT;

      sock = sockfd_lookup_light(fd, &err, &fput_needed);
      if (!sock)
            goto out;

      err = -EMSGSIZE;
      if (msg_sys.msg_iovlen > UIO_MAXIOV)
            goto out_put;
      
      /* Check whether to allocate the iovec area*/
      err = -ENOMEM;
      iov_size = msg_sys.msg_iovlen * sizeof(struct iovec);
      if (msg_sys.msg_iovlen > UIO_FASTIOV) {
            iov = sock_kmalloc(sock->sk, iov_size, GFP_KERNEL);
            if (!iov)
                  goto out_put;
      }

      /*
       *    Save the user-mode address (verify_iovec will change the
       *    kernel msghdr to use the kernel address space)
       */
       
      uaddr = (void __user *) msg_sys.msg_name;
      uaddr_len = COMPAT_NAMELEN(msg);
      if (MSG_CMSG_COMPAT & flags) {
            err = verify_compat_iovec(&msg_sys, iov, addr, VERIFY_WRITE);
      } else
            err = verify_iovec(&msg_sys, iov, addr, VERIFY_WRITE);
      if (err < 0)
            goto out_freeiov;
      total_len=err;

      cmsg_ptr = (unsigned long)msg_sys.msg_control;
      msg_sys.msg_flags = 0;
      if (MSG_CMSG_COMPAT & flags)
            msg_sys.msg_flags = MSG_CMSG_COMPAT;
      
      if (sock->file->f_flags & O_NONBLOCK)
            flags |= MSG_DONTWAIT;
      err = sock_recvmsg(sock, &msg_sys, total_len, flags);
      if (err < 0)
            goto out_freeiov;
      len = err;

      if (uaddr != NULL) {
            err = move_addr_to_user(addr, msg_sys.msg_namelen, uaddr, uaddr_len);
            if (err < 0)
                  goto out_freeiov;
      }
      err = __put_user((msg_sys.msg_flags & ~MSG_CMSG_COMPAT),
                   COMPAT_FLAGS(msg));
      if (err)
            goto out_freeiov;
      if (MSG_CMSG_COMPAT & flags)
            err = __put_user((unsigned long)msg_sys.msg_control-cmsg_ptr, 
                         &msg_compat->msg_controllen);
      else
            err = __put_user((unsigned long)msg_sys.msg_control-cmsg_ptr, 
                         &msg->msg_controllen);
      if (err)
            goto out_freeiov;
      err = len;

out_freeiov:
      if (iov != iovstack)
            sock_kfree_s(sock->sk, iov, iov_size);
out_put:
      fput_light(sock->file, fput_needed);
out:
      return err;
}

#ifdef __ARCH_WANT_SYS_SOCKETCALL

/* Argument list sizes for sys_socketcall */
#define AL(x) ((x) * sizeof(unsigned long))
static unsigned char nargs[18]={AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
                        AL(3),AL(3),AL(4),AL(4),AL(4),AL(6),
                        AL(6),AL(2),AL(5),AL(5),AL(3),AL(3)};
#undef AL

/*
 *    System call vectors. 
 *
 *    Argument checking cleaned up. Saved 20% in size.
 *  This function doesn't need to set the kernel lock because
 *  it is set by the callees. 
 */

asmlinkage long sys_socketcall(int call, unsigned long __user *args)
{
      unsigned long a[6];
      unsigned long a0,a1;
      int err;

      if(call<1||call>SYS_RECVMSG)
            return -EINVAL;

      /* copy_from_user should be SMP safe. */
      if (copy_from_user(a, args, nargs[call]))
            return -EFAULT;

      err = audit_socketcall(nargs[call]/sizeof(unsigned long), a);
      if (err)
            return err;

      a0=a[0];
      a1=a[1];
      
      switch(call) 
      {
            case SYS_SOCKET:
                  err = sys_socket(a0,a1,a[2]);
                  break;
            case SYS_BIND:
                  err = sys_bind(a0,(struct sockaddr __user *)a1, a[2]);
                  break;
            case SYS_CONNECT:
                  err = sys_connect(a0, (struct sockaddr __user *)a1, a[2]);
                  break;
            case SYS_LISTEN:
                  err = sys_listen(a0,a1);
                  break;
            case SYS_ACCEPT:
                  err = sys_accept(a0,(struct sockaddr __user *)a1, (int __user *)a[2]);
                  break;
            case SYS_GETSOCKNAME:
                  err = sys_getsockname(a0,(struct sockaddr __user *)a1, (int __user *)a[2]);
                  break;
            case SYS_GETPEERNAME:
                  err = sys_getpeername(a0, (struct sockaddr __user *)a1, (int __user *)a[2]);
                  break;
            case SYS_SOCKETPAIR:
                  err = sys_socketpair(a0,a1, a[2], (int __user *)a[3]);
                  break;
            case SYS_SEND:
                  err = sys_send(a0, (void __user *)a1, a[2], a[3]);
                  break;
            case SYS_SENDTO:
                  err = sys_sendto(a0,(void __user *)a1, a[2], a[3],
                               (struct sockaddr __user *)a[4], a[5]);
                  break;
            case SYS_RECV:
                  err = sys_recv(a0, (void __user *)a1, a[2], a[3]);
                  break;
            case SYS_RECVFROM:
                  err = sys_recvfrom(a0, (void __user *)a1, a[2], a[3],
                                 (struct sockaddr __user *)a[4], (int __user *)a[5]);
                  break;
            case SYS_SHUTDOWN:
                  err = sys_shutdown(a0,a1);
                  break;
            case SYS_SETSOCKOPT:
                  err = sys_setsockopt(a0, a1, a[2], (char __user *)a[3], a[4]);
                  break;
            case SYS_GETSOCKOPT:
                  err = sys_getsockopt(a0, a1, a[2], (char __user *)a[3], (int __user *)a[4]);
                  break;
            case SYS_SENDMSG:
                  err = sys_sendmsg(a0, (struct msghdr __user *) a1, a[2]);
                  break;
            case SYS_RECVMSG:
                  err = sys_recvmsg(a0, (struct msghdr __user *) a1, a[2]);
                  break;
            default:
                  err = -EINVAL;
                  break;
      }
      return err;
}

#endif /* __ARCH_WANT_SYS_SOCKETCALL */

/*
 *    This function is called by a protocol handler that wants to
 *    advertise its address family, and have it linked into the
 *    SOCKET module.
 */

int sock_register(struct net_proto_family *ops)
{
      int err;

      if (ops->family >= NPROTO) {
            printk(KERN_CRIT "protocol %d >= NPROTO(%d)\n", ops->family, NPROTO);
            return -ENOBUFS;
      }
      net_family_write_lock();
      err = -EEXIST;
      if (net_families[ops->family] == NULL) {
            net_families[ops->family]=ops;
            err = 0;
      }
      net_family_write_unlock();
      printk(KERN_INFO "NET: Registered protocol family %d\n",
             ops->family);
      return err;
}

/*
 *    This function is called by a protocol handler that wants to
 *    remove its address family, and have it unlinked from the
 *    SOCKET module.
 */

int sock_unregister(int family)
{
      if (family < 0 || family >= NPROTO)
            return -1;

      net_family_write_lock();
      net_families[family]=NULL;
      net_family_write_unlock();
      printk(KERN_INFO "NET: Unregistered protocol family %d\n",
             family);
      return 0;
}

static int __init sock_init(void)
{
      /*
       *    Initialize sock SLAB cache.
       */
       
      sk_init();

      /*
       *    Initialize skbuff SLAB cache 
       */
      skb_init();

      /*
       *    Initialize the protocols module. 
       */

      init_inodecache();
      register_filesystem(&sock_fs_type);
      sock_mnt = kern_mount(&sock_fs_type);

      /* The real protocol initialization is performed in later initcalls.
       */

#ifdef CONFIG_NETFILTER
      netfilter_init();
#endif

      return 0;
}

core_initcall(sock_init);     /* early initcall */

#ifdef CONFIG_PROC_FS
void socket_seq_show(struct seq_file *seq)
{
      int cpu;
      int counter = 0;

      for_each_possible_cpu(cpu)
            counter += per_cpu(sockets_in_use, cpu);

      /* It can be negative, by the way. 8) */
      if (counter < 0)
            counter = 0;

      seq_printf(seq, "sockets: used %d\n", counter);
}
#endif /* CONFIG_PROC_FS */

#ifdef CONFIG_COMPAT
static long compat_sock_ioctl(struct file *file, unsigned cmd,
                        unsigned long arg)
{
      struct socket *sock = file->private_data;
      int ret = -ENOIOCTLCMD;

      if (sock->ops->compat_ioctl)
            ret = sock->ops->compat_ioctl(sock, cmd, arg);

      return ret;
}
#endif

/* ABI emulation layers need these two */
EXPORT_SYMBOL(move_addr_to_kernel);
EXPORT_SYMBOL(move_addr_to_user);
EXPORT_SYMBOL(sock_create);
EXPORT_SYMBOL(sock_create_kern);
EXPORT_SYMBOL(sock_create_lite);
EXPORT_SYMBOL(sock_map_fd);
EXPORT_SYMBOL(sock_recvmsg);
EXPORT_SYMBOL(sock_register);
EXPORT_SYMBOL(sock_release);
EXPORT_SYMBOL(sock_sendmsg);
EXPORT_SYMBOL(sock_unregister);
EXPORT_SYMBOL(sock_wake_async);
EXPORT_SYMBOL(sockfd_lookup);
EXPORT_SYMBOL(kernel_sendmsg);
EXPORT_SYMBOL(kernel_recvmsg);

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