/*
   * 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/socket.h>
  #include <linux/file.h>
  #include <linux/net.h>
  #include <linux/interrupt.h>

  #include <linux/rcupdate.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/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 <linux/nsproxy.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, const struct iovec *iov,
  			 unsigned long nr_segs, loff_t pos);
  static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov,
  			  unsigned long nr_segs, 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_sendpage(struct file *file, struct page *page,
  			     int offset, size_t size, loff_t *ppos, int more);

  static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
  			        struct pipe_inode_info *pipe, size_t len,
  				unsigned int flags);

  /*
   *	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 const 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,

  	.sendpage =	sock_sendpage,
  	.splice_write = generic_splice_sendpage,

  	.splice_read =	sock_splice_read,

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

  static DEFINE_SPINLOCK(net_family_lock);

  static const struct net_proto_family *net_families[NPROTO] __read_mostly;

  /*
   *	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;

  	err = get_user(len, ulen);
  	if (err)

  		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 struct kmem_cache *sock_inode_cachep __read_mostly;

  
  static struct inode *sock_alloc_inode(struct super_block *sb)
  {
  	struct socket_alloc *ei;

  	ei = kmem_cache_alloc(sock_inode_cachep, GFP_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;

  
  	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(struct kmem_cache *cachep, void *foo)

  {

  	struct socket_alloc *ei = (struct socket_alloc *)foo;

  	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);

  	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)
  {

  	/*
  	 * At creation time, we pretended this dentry was hashed
  	 * (by clearing DCACHE_UNHASHED bit in d_flags)
  	 * At delete time, we restore the truth : not hashed.
  	 * (so that dput() can proceed correctly)
  	 */
  	dentry->d_flags |= DCACHE_UNHASHED;
  	return 0;

  }

  
  /*
   * sockfs_dname() is called from d_path().
   */
  static char *sockfs_dname(struct dentry *dentry, char *buffer, int buflen)
  {
  	return dynamic_dname(dentry, buffer, buflen, "socket:[%lu]",
  				dentry->d_inode->i_ino);
  }

  static struct dentry_operations sockfs_dentry_operations = {

  	.d_delete = sockfs_delete_dentry,

  	.d_dname  = sockfs_dname,

  };
  
  /*
   *	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 dentry *dentry;

  	struct qstr name = { .name = "" };

  	dentry = d_alloc(sock_mnt->mnt_sb->s_root, &name);
  	if (unlikely(!dentry))

  		return -ENOMEM;

  	dentry->d_op = &sockfs_dentry_operations;

  	/*
  	 * We dont want to push this dentry into global dentry hash table.
  	 * We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED
  	 * This permits a working /proc/$pid/fd/XXX on sockets
  	 */

  	dentry->d_flags &= ~DCACHE_UNHASHED;
  	d_instantiate(dentry, SOCK_INODE(sock));

  
  	sock->file = file;

  	init_file(file, sock_mnt, dentry, FMODE_READ | FMODE_WRITE,
  		  &socket_file_ops);
  	SOCK_INODE(sock)->i_fop = &socket_file_ops;

  	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)
  {

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

  	*err = -ENOTSOCK;
  	return NULL;

  }

  /**
   *	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;

  	file = fget(fd);
  	if (!file) {

  		*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!
  ");
  
  	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;
  }

  /*
   * called from sock_recv_timestamp() if sock_flag(sk, SOCK_RCVTSTAMP)
   */
  void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
  	struct sk_buff *skb)
  {
  	ktime_t kt = skb->tstamp;
  
  	if (!sock_flag(sk, SOCK_RCVTSTAMPNS)) {
  		struct timeval tv;
  		/* Race occurred between timestamp enabling and packet
  		   receiving.  Fill in the current time for now. */
  		if (kt.tv64 == 0)
  			kt = ktime_get_real();
  		skb->tstamp = kt;
  		tv = ktime_to_timeval(kt);
  		put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP, sizeof(tv), &tv);
  	} else {
  		struct timespec ts;
  		/* Race occurred between timestamp enabling and packet
  		   receiving.  Fill in the current time for now. */
  		if (kt.tv64 == 0)
  			kt = ktime_get_real();
  		skb->tstamp = kt;
  		ts = ktime_to_timespec(kt);
  		put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPNS, sizeof(ts), &ts);
  	}
  }

  EXPORT_SYMBOL_GPL(__sock_recv_timestamp);

  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 ssize_t sock_splice_read(struct file *file, loff_t *ppos,
  			        struct pipe_inode_info *pipe, size_t len,
  				unsigned int flags)
  {
  	struct socket *sock = file->private_data;
  
  	return sock->ops->splice_read(sock, ppos, pipe, len, flags);
  }

  static struct sock_iocb *alloc_sock_iocb(struct kiocb *iocb,

  					 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;

  	iocb->private = siocb;
  	return siocb;

  }

  static ssize_t do_sock_read(struct msghdr *msg, struct kiocb *iocb,

  		struct file *file, const 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_aio_read(struct kiocb *iocb, const struct iovec *iov,
  				unsigned long nr_segs, loff_t pos)

  {
  	struct sock_iocb siocb, *x;

  	if (pos != 0)
  		return -ESPIPE;

  
  	if (iocb->ki_left == 0)	/* Match SYS5 behaviour */

  		return 0;

  
  	x = alloc_sock_iocb(iocb, &siocb);

  	if (!x)
  		return -ENOMEM;

  	return do_sock_read(&x->async_msg, iocb, iocb->ki_filp, iov, nr_segs);

  }

  static ssize_t do_sock_write(struct msghdr *msg, struct kiocb *iocb,

  			struct file *file, const 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_aio_write(struct kiocb *iocb, const struct iovec *iov,
  			  unsigned long nr_segs, loff_t pos)

  {
  	struct sock_iocb siocb, *x;

  	if (pos != 0)
  		return -ESPIPE;

  	x = alloc_sock_iocb(iocb, &siocb);

  	if (!x)
  		return -ENOMEM;

  	return do_sock_write(&x->async_msg, iocb, iocb->ki_filp, iov, nr_segs);

  }

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

  static DEFINE_MUTEX(br_ioctl_mutex);

  static int (*br_ioctl_hook) (struct net *, unsigned int cmd, void __user *arg) = NULL;

  void brioctl_set(int (*hook) (struct net *, 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) (struct net *, void __user *arg);

  void vlan_ioctl_set(int (*hook) (struct net *, 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;

  	struct sock *sk;

  	void __user *argp = (void __user *)arg;
  	int pid, err;

  	struct net *net;

  	sock = file->private_data;

  	sk = sock->sk;
  	net = sk->sk_net;

  	if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {

  		err = dev_ioctl(net, cmd, argp);

  	} else

  #ifdef CONFIG_WIRELESS_EXT

  	if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {

  		err = dev_ioctl(net, 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(f_getown(sock->file),

  				       (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(net, 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(net, argp);

  			mutex_unlock(&vlan_ioctl_mutex);

  			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(net, 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;
  	}

  	sock->type = type;

  	err = security_socket_post_create(sock, family, type, protocol, 1);
  	if (err)
  		goto out_release;

  out:
  	*res = sock;
  	return err;

  out_release:
  	sock_release(sock);
  	sock = NULL;
  	goto out;

  }
  
  /* 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
  ");
  		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;

  	sk = sock->sk;
  	if (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 SOCK_WAKE_WAITD:

  		if (test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
  			break;
  		goto call_kill;

  	case SOCK_WAKE_SPACE:

  		if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags))
  			break;
  		/* fall through */

  	case SOCK_WAKE_IO:

  call_kill:

  		__kill_fasync(sock->fasync_list, SIGIO, band);
  		break;

  	case SOCK_WAKE_URG:

  		__kill_fasync(sock->fasync_list, SIGURG, band);
  	}
  	return 0;
  }

  static int __sock_create(struct net *net, int family, int type, int protocol,

  			 struct socket **res, int kern)

  {
  	int err;
  	struct socket *sock;

  	const struct net_proto_family *pf;

  
  	/*

  	 *      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)
  ",
  			       current->comm);

  		}
  		family = PF_PACKET;
  	}
  
  	err = security_socket_create(family, type, protocol, kern);
  	if (err)
  		return err;

  	/*
  	 *	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.
  	 */
  	sock = sock_alloc();
  	if (!sock) {
  		if (net_ratelimit())
  			printk(KERN_WARNING "socket: no more sockets
  ");
  		return -ENFILE;	/* Not exactly a match, but its the
  				   closest posix thing */
  	}
  
  	sock->type = type;

  #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

  	rcu_read_lock();
  	pf = rcu_dereference(net_families[family]);
  	err = -EAFNOSUPPORT;
  	if (!pf)
  		goto out_release;

  
  	/*
  	 * We will call the ->create function, that possibly is in a loadable
  	 * module, so we have to bump that loadable module refcnt first.
  	 */

  	if (!try_module_get(pf->owner))

  		goto out_release;

  	/* Now protected by module ref count */
  	rcu_read_unlock();

  	err = pf->create(net, sock, protocol);

  	if (err < 0)

  		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))
  		goto out_module_busy;

  	/*
  	 * Now that we're done with the ->create function, the [loadable]
  	 * module can have its refcnt decremented
  	 */

  	module_put(pf->owner);

  	err = security_socket_post_create(sock, family, type, protocol, kern);
  	if (err)

  		goto out_sock_release;

  	*res = sock;

  	return 0;
  
  out_module_busy:
  	err = -EAFNOSUPPORT;

  out_module_put:

  	sock->ops = NULL;
  	module_put(pf->owner);
  out_sock_release:

  	sock_release(sock);

  	return err;
  
  out_release:
  	rcu_read_unlock();
  	goto out_sock_release;

  }
  
  int sock_create(int family, int type, int protocol, struct socket **res)
  {

  	return __sock_create(current->nsproxy->net_ns, family, type, protocol, res, 0);

  }
  
  int sock_create_kern(int family, int type, int protocol, struct socket **res)
  {

  	return __sock_create(&init_net, 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;

  	struct file *newfile1, *newfile2;

  
  	/*
  	 * 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 = sock_alloc_fd(&newfile1);

  	if (unlikely(fd1 < 0)) {
  		err = fd1;

  		goto out_release_both;

  	}

  	fd2 = sock_alloc_fd(&newfile2);
  	if (unlikely(fd2 < 0)) {

  		err = fd2;

  		put_filp(newfile1);
  		put_unused_fd(fd1);

  		goto out_release_both;

  	}

  	err = sock_attach_fd(sock1, newfile1);
  	if (unlikely(err < 0)) {
  		goto out_fd2;
  	}
  
  	err = sock_attach_fd(sock2, newfile2);
  	if (unlikely(err < 0)) {
  		fput(newfile1);
  		goto out_fd1;
  	}
  
  	err = audit_fd_pair(fd1, fd2);
  	if (err < 0) {
  		fput(newfile1);
  		fput(newfile2);
  		goto out_fd;
  	}

  	fd_install(fd1, newfile1);
  	fd_install(fd2, newfile2);

  	/* 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_release_both:

  	sock_release(sock2);

  out_release_1:

  	sock_release(sock1);

  out:
  	return err;

  
  out_fd2:
  	put_filp(newfile1);
  	sock_release(sock1);
  out_fd1:
  	put_filp(newfile2);
  	sock_release(sock2);
  out_fd:
  	put_unused_fd(fd1);
  	put_unused_fd(fd2);
  	goto out;

  }

  /*
   *	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;

  	sock = sockfd_lookup_light(fd, &err, &fput_needed);

  	if (sock) {

  		err = move_addr_to_kernel(umyaddr, addrlen, address);
  		if (err >= 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.
   */

  asmlinkage long sys_listen(int fd, int backlog)
  {
  	struct socket *sock;

  	int err, fput_needed;

  	int somaxconn;

  
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (sock) {

  		somaxconn = sock->sk->sk_net->sysctl_somaxconn;
  		if ((unsigned)backlog > somaxconn)
  			backlog = 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_simple;

  	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_simple:
  	sock_release(newsock);
  	put_filp(newfile);
  	put_unused_fd(newfd);
  	goto out_put;

  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;

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

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

  		goto out;

  	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);

  out:

  	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;

  	int fput_needed;

  	sock = sockfd_lookup_light(fd, &err, &fput_needed);

  	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;

  	}

  
  	fput_light(sock->file, fput_needed);

  out:

  	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;

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

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

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

  {