/*
 * 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/thread_info.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 <linux/magic.h>
#include <linux/slab.h>
#include <linux/xattr.h>

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

#include <net/compat.h>
#include <net/wext.h>
#include <net/cls_cgroup.h>

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

#include <linux/if_tun.h>
#include <linux/ipv6_route.h>
#include <linux/route.h>
#include <linux/sockios.h>
#include <linux/atalk.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 __rcu *net_families[NPROTO] __read_mostly;

/*
 *      Statistics counters of the socket lists
 */

static DEFINE_PER_CPU(int, sockets_in_use);

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

/**
 *      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, struct sockaddr_storage *kaddr)
{
        if (ulen < 0 || ulen > sizeof(struct sockaddr_storage))
                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.
 */

static int move_addr_to_user(struct sockaddr_storage *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 > sizeof(struct sockaddr_storage))
                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);
}

static struct kmem_cache *sock_inode_cachep __read_mostly;

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

        ei = kmem_cache_alloc(sock_inode_cachep, GFP_KERNEL);
        if (!ei)
                return NULL;
        wq = kmalloc(sizeof(*wq), GFP_KERNEL);
        if (!wq) {
                kmem_cache_free(sock_inode_cachep, ei);
                return NULL;
        }
        init_waitqueue_head(&wq->wait);
        wq->fasync_list = NULL;
        RCU_INIT_POINTER(ei->socket.wq, wq);

        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)
{
        struct socket_alloc *ei;
        struct socket_wq *wq;

        ei = container_of(inode, struct socket_alloc, vfs_inode);
        wq = rcu_dereference_protected(ei->socket.wq, 1);
        kfree_rcu(wq, rcu);
        kmem_cache_free(sock_inode_cachep, ei);
}

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

/*
 * 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 const struct dentry_operations sockfs_dentry_operations = {
        .d_dname  = sockfs_dname,
};

static struct dentry *sockfs_mount(struct file_system_type *fs_type,
                         int flags, const char *dev_name, void *data)
{
        return mount_pseudo(fs_type, "socket:", &sockfs_ops,
                &sockfs_dentry_operations, SOCKFS_MAGIC);
}

static struct vfsmount *sock_mnt __read_mostly;

static struct file_system_type sock_fs_type = {
        .name =         "sockfs",
        .mount =        sockfs_mount,
        .kill_sb =      kill_anon_super,
};

/*
 *      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.
 */

struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname)
{
        struct qstr name = { .name = "" };
        struct path path;
        struct file *file;

        if (dname) {
                name.name = dname;
                name.len = strlen(name.name);
        } else if (sock->sk) {
                name.name = sock->sk->sk_prot_creator->name;
                name.len = strlen(name.name);
        }
        path.dentry = d_alloc_pseudo(sock_mnt->mnt_sb, &name);
        if (unlikely(!path.dentry))
                return ERR_PTR(-ENOMEM);
        path.mnt = mntget(sock_mnt);

        d_instantiate(path.dentry, SOCK_INODE(sock));
        SOCK_INODE(sock)->i_fop = &socket_file_ops;

        file = alloc_file(&path, FMODE_READ | FMODE_WRITE,
                  &socket_file_ops);
        if (unlikely(!file)) {
                /* drop dentry, keep inode */
                ihold(path.dentry->d_inode);
                path_put(&path);
                return ERR_PTR(-ENFILE);
        }

        sock->file = file;
        file->f_flags = O_RDWR | (flags & O_NONBLOCK);
        file->f_pos = 0;
        file->private_data = sock;
        return file;
}
EXPORT_SYMBOL(sock_alloc_file);

static int sock_map_fd(struct socket *sock, int flags)
{
        struct file *newfile;
        int fd = get_unused_fd_flags(flags);
        if (unlikely(fd < 0))
                return fd;

        newfile = sock_alloc_file(sock, flags, NULL);
        if (likely(!IS_ERR(newfile))) {
                fd_install(fd, newfile);
                return fd;
        }

        put_unused_fd(fd);
        return PTR_ERR(newfile);
}

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;
}
EXPORT_SYMBOL(sock_from_file);

/**
 *      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;
}
EXPORT_SYMBOL(sockfd_lookup);

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;
}

#define XATTR_SOCKPROTONAME_SUFFIX "sockprotoname"
#define XATTR_NAME_SOCKPROTONAME (XATTR_SYSTEM_PREFIX XATTR_SOCKPROTONAME_SUFFIX)
#define XATTR_NAME_SOCKPROTONAME_LEN (sizeof(XATTR_NAME_SOCKPROTONAME)-1)
static ssize_t sockfs_getxattr(struct dentry *dentry,
                               const char *name, void *value, size_t size)
{
        const char *proto_name;
        size_t proto_size;
        int error;

        error = -ENODATA;
        if (!strncmp(name, XATTR_NAME_SOCKPROTONAME, XATTR_NAME_SOCKPROTONAME_LEN)) {
                proto_name = dentry->d_name.name;
                proto_size = strlen(proto_name);

                if (value) {
                        error = -ERANGE;
                        if (proto_size + 1 > size)
                                goto out;

                        strncpy(value, proto_name, proto_size + 1);
                }
                error = proto_size + 1;
        }

out:
        return error;
}

static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
                                size_t size)
{
        ssize_t len;
        ssize_t used = 0;

        len = security_inode_listsecurity(dentry->d_inode, buffer, size);
        if (len < 0)
                return len;
        used += len;
        if (buffer) {
                if (size < used)
                        return -ERANGE;
                buffer += len;
        }

        len = (XATTR_NAME_SOCKPROTONAME_LEN + 1);
        used += len;
        if (buffer) {
                if (size < used)
                        return -ERANGE;
                memcpy(buffer, XATTR_NAME_SOCKPROTONAME, len);
                buffer += len;
        }

        return used;
}

static const struct inode_operations sockfs_inode_ops = {
        .getxattr = sockfs_getxattr,
        .listxattr = sockfs_listxattr,
};

/**
 *      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_pseudo(sock_mnt->mnt_sb);
        if (!inode)
                return NULL;

        sock = SOCKET_I(inode);

        kmemcheck_annotate_bitfield(sock, type);
        inode->i_ino = get_next_ino();
        inode->i_mode = S_IFSOCK | S_IRWXUGO;
        inode->i_uid = current_fsuid();
        inode->i_gid = current_fsgid();
        inode->i_op = &sockfs_inode_ops;

        this_cpu_add(sockets_in_use, 1);
        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,
        .llseek = noop_llseek,
};

/**
 *      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 (rcu_dereference_protected(sock->wq, 1)->fasync_list)
                printk(KERN_ERR "sock_release: fasync list not empty!\n");

        if (test_bit(SOCK_EXTERNALLY_ALLOCATED, &sock->flags))
                return;

        this_cpu_sub(sockets_in_use, 1);
        if (!sock->file) {
                iput(SOCK_INODE(sock));
                return;
        }
        sock->file = NULL;
}
EXPORT_SYMBOL(sock_release);

int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags)
{
        *tx_flags = 0;
        if (sock_flag(sk, SOCK_TIMESTAMPING_TX_HARDWARE))
                *tx_flags |= SKBTX_HW_TSTAMP;
        if (sock_flag(sk, SOCK_TIMESTAMPING_TX_SOFTWARE))
                *tx_flags |= SKBTX_SW_TSTAMP;
        if (sock_flag(sk, SOCK_WIFI_STATUS))
                *tx_flags |= SKBTX_WIFI_STATUS;
        return 0;
}
EXPORT_SYMBOL(sock_tx_timestamp);

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

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

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

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

        return err ?: __sock_sendmsg_nosec(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;
}
EXPORT_SYMBOL(sock_sendmsg);

static int sock_sendmsg_nosec(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_nosec(&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;
}
EXPORT_SYMBOL(kernel_sendmsg);

static int ktime2ts(ktime_t kt, struct timespec *ts)
{
        if (kt.tv64) {
                *ts = ktime_to_timespec(kt);
                return 1;
        } else {
                return 0;
        }
}

/*
 * 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)
{
        int need_software_tstamp = sock_flag(sk, SOCK_RCVTSTAMP);
        struct timespec ts[3];
        int empty = 1;
        struct skb_shared_hwtstamps *shhwtstamps =
                skb_hwtstamps(skb);

        /* Race occurred between timestamp enabling and packet
           receiving.  Fill in the current time for now. */
        if (need_software_tstamp && skb->tstamp.tv64 == 0)
                __net_timestamp(skb);

        if (need_software_tstamp) {
                if (!sock_flag(sk, SOCK_RCVTSTAMPNS)) {
                        struct timeval tv;
                        skb_get_timestamp(skb, &tv);
                        put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
                                 sizeof(tv), &tv);
                } else {
                        skb_get_timestampns(skb, &ts[0]);
                        put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPNS,
                                 sizeof(ts[0]), &ts[0]);
                }
        }


        memset(ts, 0, sizeof(ts));
        if (skb->tstamp.tv64 &&
            sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) {
                skb_get_timestampns(skb, ts + 0);
                empty = 0;
        }
        if (shhwtstamps) {
                if (sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE) &&
                    ktime2ts(shhwtstamps->syststamp, ts + 1))
                        empty = 0;
                if (sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE) &&
                    ktime2ts(shhwtstamps->hwtstamp, ts + 2))
                        empty = 0;
        }
        if (!empty)
                put_cmsg(msg, SOL_SOCKET,
                         SCM_TIMESTAMPING, sizeof(ts), &ts);
}
EXPORT_SYMBOL_GPL(__sock_recv_timestamp);

void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
        struct sk_buff *skb)
{
        int ack;

        if (!sock_flag(sk, SOCK_WIFI_STATUS))
                return;
        if (!skb->wifi_acked_valid)
                return;

        ack = skb->wifi_acked;

        put_cmsg(msg, SOL_SOCKET, SCM_WIFI_STATUS, sizeof(ack), &ack);
}
EXPORT_SYMBOL_GPL(__sock_recv_wifi_status);

static inline void sock_recv_drops(struct msghdr *msg, struct sock *sk,
                                   struct sk_buff *skb)
{
        if (sock_flag(sk, SOCK_RXQ_OVFL) && skb && skb->dropcount)
                put_cmsg(msg, SOL_SOCKET, SO_RXQ_OVFL,
                        sizeof(__u32), &skb->dropcount);
}

void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
        struct sk_buff *skb)
{
        sock_recv_timestamp(msg, sk, skb);
        sock_recv_drops(msg, sk, skb);
}
EXPORT_SYMBOL_GPL(__sock_recv_ts_and_drops);

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

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

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

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

        return err ?: __sock_recvmsg_nosec(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;
}
EXPORT_SYMBOL(sock_recvmsg);

static int sock_recvmsg_nosec(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_nosec(&iocb, sock, msg, size, flags);
        if (-EIOCBQUEUED == ret)
                ret = wait_on_sync_kiocb(&iocb);
        return ret;
}

/**
 * kernel_recvmsg - Receive a message from a socket (kernel space)
 * @sock:       The socket to receive the message from
 * @msg:        Received message
 * @vec:        Input s/g array for message data
 * @num:        Size of input s/g array
 * @size:       Number of bytes to read
 * @flags:      Message flags (MSG_DONTWAIT, etc...)
 *
 * On return the msg structure contains the scatter/gather array passed in the
 * vec argument. The array is modified so that it consists of the unfilled
 * portion of the original array.
 *
 * The returned value is the total number of bytes received, or an error.
 */
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;
}
EXPORT_SYMBOL(kernel_recvmsg);

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) ? MSG_DONTWAIT : 0;
        /* more is a combination of MSG_MORE and MSG_SENDPAGE_NOTLAST */
        flags |= more;

        return kernel_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;

        if (unlikely(!sock->ops->splice_read))
                return -EINVAL;

        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);

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);

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

        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);

        return err;
}

/*
 *      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 = sock_net(sk);
        if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {
                err = dev_ioctl(net, cmd, argp);
        } else
#ifdef CONFIG_WEXT_CORE
        if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {
                err = dev_ioctl(net, cmd, argp);
        } else
#endif
                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");

                        mutex_lock(&dlci_ioctl_mutex);
                        if (dlci_ioctl_hook)
                                err = dlci_ioctl_hook(cmd, argp);
                        mutex_unlock(&dlci_ioctl_mutex);
                        break;
                default:
                        err = sock_do_ioctl(net, sock, cmd, arg);
                        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;
}
EXPORT_SYMBOL(sock_create_lite);

/* 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_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
 */

static int sock_fasync(int fd, struct file *filp, int on)
{
        struct socket *sock = filp->private_data;
        struct sock *sk = sock->sk;
        struct socket_wq *wq;

        if (sk == NULL)
                return -EINVAL;

        lock_sock(sk);
        wq = rcu_dereference_protected(sock->wq, sock_owned_by_user(sk));
        fasync_helper(fd, filp, on, &wq->fasync_list);

        if (!wq->fasync_list)
                sock_reset_flag(sk, SOCK_FASYNC);
        else
                sock_set_flag(sk, SOCK_FASYNC);

        release_sock(sk);
        return 0;
}

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

int sock_wake_async(struct socket *sock, int how, int band)
{
        struct socket_wq *wq;

        if (!sock)
                return -1;
        rcu_read_lock();
        wq = rcu_dereference(sock->wq);
        if (!wq || !wq->fasync_list) {
                rcu_read_unlock();
                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(&wq->fasync_list, SIGIO, band);
                break;
        case SOCK_WAKE_URG:
                kill_fasync(&wq->fasync_list, SIGURG, band);
        }
        rcu_read_unlock();
        return 0;
}
EXPORT_SYMBOL(sock_wake_async);

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)\n",
                               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) {
                net_warn_ratelimited("socket: no more sockets\n");
                return -ENFILE; /* Not exactly a match, but its the
                                   closest posix thing */
        }

        sock->type = type;

#ifdef CONFIG_MODULES
        /* 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 (rcu_access_pointer(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, kern);
        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;
}
EXPORT_SYMBOL(__sock_create);

int sock_create(int family, int type, int protocol, struct socket **res)
{
        return __sock_create(current->nsproxy->net_ns, family, type, protocol, res, 0);
}
EXPORT_SYMBOL(sock_create);

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

SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
{
        int retval;
        struct socket *sock;
        int flags;

        /* Check the SOCK_* constants for consistency.  */
        BUILD_BUG_ON(SOCK_CLOEXEC != O_CLOEXEC);
        BUILD_BUG_ON((SOCK_MAX | SOCK_TYPE_MASK) != SOCK_TYPE_MASK);
        BUILD_BUG_ON(SOCK_CLOEXEC & SOCK_TYPE_MASK);
        BUILD_BUG_ON(SOCK_NONBLOCK & SOCK_TYPE_MASK);

        flags = type & ~SOCK_TYPE_MASK;
        if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
                return -EINVAL;
        type &= SOCK_TYPE_MASK;

        if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
                flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;

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

        retval = sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));
        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.
 */

SYSCALL_DEFINE4(socketpair, int, family, int, type, int, protocol,
                int __user *, usockvec)
{
        struct socket *sock1, *sock2;
        int fd1, fd2, err;
        struct file *newfile1, *newfile2;
        int flags;

        flags = type & ~SOCK_TYPE_MASK;
        if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
                return -EINVAL;
        type &= SOCK_TYPE_MASK;

        if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
                flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;

        /*
         * 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 = get_unused_fd_flags(flags);
        if (unlikely(fd1 < 0)) {
                err = fd1;
                goto out_release_both;
        }
        fd2 = get_unused_fd_flags(flags);
        if (unlikely(fd2 < 0)) {
                err = fd2;
                put_unused_fd(fd1);
                goto out_release_both;
        }

        newfile1 = sock_alloc_file(sock1, flags, NULL);
        if (unlikely(IS_ERR(newfile1))) {
                err = PTR_ERR(newfile1);
                put_unused_fd(fd1);
                put_unused_fd(fd2);
                goto out_release_both;
        }

        newfile2 = sock_alloc_file(sock2, flags, NULL);
        if (IS_ERR(newfile2)) {
                err = PTR_ERR(newfile2);
                fput(newfile1);
                put_unused_fd(fd1);
                put_unused_fd(fd2);
                sock_release(sock2);
                goto out;
        }

        audit_fd_pair(fd1, fd2);
        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;
}

/*
 *      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).
 */

SYSCALL_DEFINE3(bind, int, fd, struct sockaddr __user *, umyaddr, int, addrlen)
{
        struct socket *sock;
        struct sockaddr_storage address;
        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.
 */

SYSCALL_DEFINE2(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_net(sock->sk)->core.sysctl_somaxconn;
                if ((unsigned int)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.
 */

SYSCALL_DEFINE4(accept4, int, fd, struct sockaddr __user *, upeer_sockaddr,
                int __user *, upeer_addrlen, int, flags)
{
        struct socket *sock, *newsock;
        struct file *newfile;
        int err, len, newfd, fput_needed;
        struct sockaddr_storage address;

        if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
                return -EINVAL;

        if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
                flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;

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

        err = -ENFILE;
        newsock = sock_alloc();
        if (!newsock)
                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 = get_unused_fd_flags(flags);
        if (unlikely(newfd < 0)) {
                err = newfd;
                sock_release(newsock);
                goto out_put;
        }
        newfile = sock_alloc_file(newsock, flags, sock->sk->sk_prot_creator->name);
        if (unlikely(IS_ERR(newfile))) {
                err = PTR_ERR(newfile);
                put_unused_fd(newfd);
                sock_release(newsock);
                goto out_put;
        }

        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;

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

SYSCALL_DEFINE3(accept, int, fd, struct sockaddr __user *, upeer_sockaddr,
                int __user *, upeer_addrlen)
{
        return sys_accept4(fd, upeer_sockaddr, upeer_addrlen, 0);
}

/*
 *      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.
 */

SYSCALL_DEFINE3(connect, int, fd, struct sockaddr __user *, uservaddr,
                int, addrlen)
{
        struct socket *sock;
        struct sockaddr_storage address;
        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.
 */

SYSCALL_DEFINE3(getsockname, int, fd, struct sockaddr __user *, usockaddr,
                int __user *, usockaddr_len)
{
        struct socket *sock;
        struct sockaddr_storage address;
        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.
 */

SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr,
                int __user *, usockaddr_len)
{
        struct socket *sock;
        struct sockaddr_storage address;
        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.
 */

SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len,
                unsigned int, flags, struct sockaddr __user *, addr,
                int, addr_len)
{
        struct socket *sock;
        struct sockaddr_storage address;
        int err;
        struct msghdr msg;
        struct iovec iov;
        int fput_needed;

        if (len > INT_MAX)
                len = INT_MAX;
        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 = (struct sockaddr *)&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.
 */

SYSCALL_DEFINE4(send, int, fd, void __user *, buff, size_t, len,
                unsigned int, 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.
 */

SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
                unsigned int, flags, struct sockaddr __user *, addr,
                int __user *, addr_len)
{
        struct socket *sock;
        struct iovec iov;
        struct msghdr msg;
        struct sockaddr_storage address;
        int err, err2;
        int fput_needed;

        if (size > INT_MAX)
                size = INT_MAX;
        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 = (struct sockaddr *)&address;
        msg.msg_namelen = sizeof(address);
        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 int 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.
 */

SYSCALL_DEFINE5(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.
 */

SYSCALL_DEFINE5(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.
 */

SYSCALL_DEFINE2(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)

struct used_address {
        struct sockaddr_storage name;
        unsigned int name_len;
};

static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
                         struct msghdr *msg_sys, unsigned int flags,
                         struct used_address *used_address)
{
        struct compat_msghdr __user *msg_compat =
            (struct compat_msghdr __user *)msg;
        struct sockaddr_storage address;
        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;
        int err, ctl_len, total_len;

        err = -EFAULT;
        if (MSG_CMSG_COMPAT & flags) {
                if (get_compat_msghdr(msg_sys, msg_compat))
                        return -EFAULT;