text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * 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 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/if_bridge.h>
  #include <linux/if_frad.h>
  #include <linux/if_vlan.h>
  #include <linux/ptp_classify.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/pseudo_fs.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 <linux/nospec.h>
  #include <linux/indirect_call_wrapper.h>
  
  #include <linux/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 <net/busy_poll.h>
  #include <linux/errqueue.h>
  
  #ifdef CONFIG_NET_RX_BUSY_POLL
  unsigned int sysctl_net_busy_read __read_mostly;
  unsigned int sysctl_net_busy_poll __read_mostly;
  #endif
  
  static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to);
  static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from);
  static int sock_mmap(struct file *file, struct vm_area_struct *vma);
  
  static int sock_close(struct inode *inode, struct file *file);
  static __poll_t 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,
  	.read_iter =	sock_read_iter,
  	.write_iter =	sock_write_iter,
  	.poll =		sock_poll,
  	.unlocked_ioctl = sock_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl = compat_sock_ioctl,
  #endif
  	.mmap =		sock_mmap,
  	.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;
  
  /*
   * 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;
  
  	BUG_ON(klen > sizeof(struct sockaddr_storage));
  	err = get_user(len, ulen);
  	if (err)
  		return err;
  	if (len > klen)
  		len = klen;
  	if (len < 0)
  		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 __ro_after_init;
  
  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.wq.wait);
  	ei->socket.wq.fasync_list = NULL;
  	ei->socket.wq.flags = 0;
  
  	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_free_inode(struct inode *inode)
  {
  	struct socket_alloc *ei;
  
  	ei = container_of(inode, struct socket_alloc, vfs_inode);
  	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 void 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 | SLAB_ACCOUNT),
  					      init_once);
  	BUG_ON(sock_inode_cachep == NULL);
  }
  
  static const struct super_operations sockfs_ops = {
  	.alloc_inode	= sock_alloc_inode,
  	.free_inode	= sock_free_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]",
  				d_inode(dentry)->i_ino);
  }
  
  static const struct dentry_operations sockfs_dentry_operations = {
  	.d_dname  = sockfs_dname,
  };
  
  static int sockfs_xattr_get(const struct xattr_handler *handler,
  			    struct dentry *dentry, struct inode *inode,
  			    const char *suffix, void *value, size_t size)
  {
  	if (value) {
  		if (dentry->d_name.len + 1 > size)
  			return -ERANGE;
  		memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
  	}
  	return dentry->d_name.len + 1;
  }
  
  #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 const struct xattr_handler sockfs_xattr_handler = {
  	.name = XATTR_NAME_SOCKPROTONAME,
  	.get = sockfs_xattr_get,
  };
  
  static int sockfs_security_xattr_set(const struct xattr_handler *handler,
  				     struct dentry *dentry, struct inode *inode,
  				     const char *suffix, const void *value,
  				     size_t size, int flags)
  {
  	/* Handled by LSM. */
  	return -EAGAIN;
  }
  
  static const struct xattr_handler sockfs_security_xattr_handler = {
  	.prefix = XATTR_SECURITY_PREFIX,
  	.set = sockfs_security_xattr_set,
  };
  
  static const struct xattr_handler *sockfs_xattr_handlers[] = {
  	&sockfs_xattr_handler,
  	&sockfs_security_xattr_handler,
  	NULL
  };
  
  static int sockfs_init_fs_context(struct fs_context *fc)
  {
  	struct pseudo_fs_context *ctx = init_pseudo(fc, SOCKFS_MAGIC);
  	if (!ctx)
  		return -ENOMEM;
  	ctx->ops = &sockfs_ops;
  	ctx->dops = &sockfs_dentry_operations;
  	ctx->xattr = sockfs_xattr_handlers;
  	return 0;
  }
  
  static struct vfsmount *sock_mnt __read_mostly;
  
  static struct file_system_type sock_fs_type = {
  	.name =		"sockfs",
  	.init_fs_context = sockfs_init_fs_context,
  	.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.
   */
  
  /**
   *	sock_alloc_file - Bind a &socket to a &file
   *	@sock: socket
   *	@flags: file status flags
   *	@dname: protocol name
   *
   *	Returns the &file bound with @sock, implicitly storing it
   *	in sock->file. If dname is %NULL, sets to "".
   *	On failure the return is a ERR pointer (see linux/err.h).
   *	This function uses GFP_KERNEL internally.
   */
  
  struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname)
  {
  	struct file *file;
  
  	if (!dname)
  		dname = sock->sk ? sock->sk->sk_prot_creator->name : "";
  
  	file = alloc_file_pseudo(SOCK_INODE(sock), sock_mnt, dname,
  				O_RDWR | (flags & O_NONBLOCK),
  				&socket_file_ops);
  	if (IS_ERR(file)) {
  		sock_release(sock);
  		return file;
  	}
  
  	sock->file = file;
  	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)) {
  		sock_release(sock);
  		return fd;
  	}
  
  	newfile = sock_alloc_file(sock, flags, NULL);
  	if (!IS_ERR(newfile)) {
  		fd_install(fd, newfile);
  		return fd;
  	}
  
  	put_unused_fd(fd);
  	return PTR_ERR(newfile);
  }
  
  /**
   *	sock_from_file - Return the &socket bounded to @file.
   *	@file: file
   *	@err: pointer to an error code return
   *
   *	On failure returns %NULL and assigns -ENOTSOCK to @err.
   */
  
  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
   *	to 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 fd f = fdget(fd);
  	struct socket *sock;
  
  	*err = -EBADF;
  	if (f.file) {
  		sock = sock_from_file(f.file, err);
  		if (likely(sock)) {
  			*fput_needed = f.flags & FDPUT_FPUT;
  			return sock;
  		}
  		fdput(f);
  	}
  	return NULL;
  }
  
  static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
  				size_t size)
  {
  	ssize_t len;
  	ssize_t used = 0;
  
  	len = security_inode_listsecurity(d_inode(dentry), 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 int sockfs_setattr(struct dentry *dentry, struct iattr *iattr)
  {
  	int err = simple_setattr(dentry, iattr);
  
  	if (!err && (iattr->ia_valid & ATTR_UID)) {
  		struct socket *sock = SOCKET_I(d_inode(dentry));
  
  		if (sock->sk)
  			sock->sk->sk_uid = iattr->ia_uid;
  		else
  			err = -ENOENT;
  	}
  
  	return err;
  }
  
  static const struct inode_operations sockfs_inode_ops = {
  	.listxattr = sockfs_listxattr,
  	.setattr = sockfs_setattr,
  };
  
  /**
   *	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. This functions uses GFP_KERNEL internally.
   */
  
  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);
  
  	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;
  
  	return sock;
  }
  EXPORT_SYMBOL(sock_alloc);
  
  /**
   *	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.
   */
  
  static void __sock_release(struct socket *sock, struct inode *inode)
  {
  	if (sock->ops) {
  		struct module *owner = sock->ops->owner;
  
  		if (inode)
  			inode_lock(inode);
  		sock->ops->release(sock);
  		sock->sk = NULL;
  		if (inode)
  			inode_unlock(inode);
  		sock->ops = NULL;
  		module_put(owner);
  	}
  
  	if (sock->wq.fasync_list)
  		pr_err("%s: fasync list not empty!\n", __func__);
  
  	if (!sock->file) {
  		iput(SOCK_INODE(sock));
  		return;
  	}
  	sock->file = NULL;
  }
  
  void sock_release(struct socket *sock)
  {
  	__sock_release(sock, NULL);
  }
  EXPORT_SYMBOL(sock_release);
  
  void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags)
  {
  	u8 flags = *tx_flags;
  
  	if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE)
  		flags |= SKBTX_HW_TSTAMP;
  
  	if (tsflags & SOF_TIMESTAMPING_TX_SOFTWARE)
  		flags |= SKBTX_SW_TSTAMP;
  
  	if (tsflags & SOF_TIMESTAMPING_TX_SCHED)
  		flags |= SKBTX_SCHED_TSTAMP;
  
  	*tx_flags = flags;
  }
  EXPORT_SYMBOL(__sock_tx_timestamp);
  
  INDIRECT_CALLABLE_DECLARE(int inet_sendmsg(struct socket *, struct msghdr *,
  					   size_t));
  INDIRECT_CALLABLE_DECLARE(int inet6_sendmsg(struct socket *, struct msghdr *,
  					    size_t));
  static inline int sock_sendmsg_nosec(struct socket *sock, struct msghdr *msg)
  {
  	int ret = INDIRECT_CALL_INET(sock->ops->sendmsg, inet6_sendmsg,
  				     inet_sendmsg, sock, msg,
  				     msg_data_left(msg));
  	BUG_ON(ret == -EIOCBQUEUED);
  	return ret;
  }
  
  /**
   *	sock_sendmsg - send a message through @sock
   *	@sock: socket
   *	@msg: message to send
   *
   *	Sends @msg through @sock, passing through LSM.
   *	Returns the number of bytes sent, or an error code.
   */
  int sock_sendmsg(struct socket *sock, struct msghdr *msg)
  {
  	int err = security_socket_sendmsg(sock, msg,
  					  msg_data_left(msg));
  
  	return err ?: sock_sendmsg_nosec(sock, msg);
  }
  EXPORT_SYMBOL(sock_sendmsg);
  
  /**
   *	kernel_sendmsg - send a message through @sock (kernel-space)
   *	@sock: socket
   *	@msg: message header
   *	@vec: kernel vec
   *	@num: vec array length
   *	@size: total message data size
   *
   *	Builds the message data with @vec and sends it through @sock.
   *	Returns the number of bytes sent, or an error code.
   */
  
  int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
  		   struct kvec *vec, size_t num, size_t size)
  {
  	iov_iter_kvec(&msg->msg_iter, WRITE, vec, num, size);
  	return sock_sendmsg(sock, msg);
  }
  EXPORT_SYMBOL(kernel_sendmsg);
  
  /**
   *	kernel_sendmsg_locked - send a message through @sock (kernel-space)
   *	@sk: sock
   *	@msg: message header
   *	@vec: output s/g array
   *	@num: output s/g array length
   *	@size: total message data size
   *
   *	Builds the message data with @vec and sends it through @sock.
   *	Returns the number of bytes sent, or an error code.
   *	Caller must hold @sk.
   */
  
  int kernel_sendmsg_locked(struct sock *sk, struct msghdr *msg,
  			  struct kvec *vec, size_t num, size_t size)
  {
  	struct socket *sock = sk->sk_socket;
  
  	if (!sock->ops->sendmsg_locked)
  		return sock_no_sendmsg_locked(sk, msg, size);
  
  	iov_iter_kvec(&msg->msg_iter, WRITE, vec, num, size);
  
  	return sock->ops->sendmsg_locked(sk, msg, msg_data_left(msg));
  }
  EXPORT_SYMBOL(kernel_sendmsg_locked);
  
  static bool skb_is_err_queue(const struct sk_buff *skb)
  {
  	/* pkt_type of skbs enqueued on the error queue are set to
  	 * PACKET_OUTGOING in skb_set_err_queue(). This is only safe to do
  	 * in recvmsg, since skbs received on a local socket will never
  	 * have a pkt_type of PACKET_OUTGOING.
  	 */
  	return skb->pkt_type == PACKET_OUTGOING;
  }
  
  /* On transmit, software and hardware timestamps are returned independently.
   * As the two skb clones share the hardware timestamp, which may be updated
   * before the software timestamp is received, a hardware TX timestamp may be
   * returned only if there is no software TX timestamp. Ignore false software
   * timestamps, which may be made in the __sock_recv_timestamp() call when the
   * option SO_TIMESTAMP_OLD(NS) is enabled on the socket, even when the skb has a
   * hardware timestamp.
   */
  static bool skb_is_swtx_tstamp(const struct sk_buff *skb, int false_tstamp)
  {
  	return skb->tstamp && !false_tstamp && skb_is_err_queue(skb);
  }
  
  static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb)
  {
  	struct scm_ts_pktinfo ts_pktinfo;
  	struct net_device *orig_dev;
  
  	if (!skb_mac_header_was_set(skb))
  		return;
  
  	memset(&ts_pktinfo, 0, sizeof(ts_pktinfo));
  
  	rcu_read_lock();
  	orig_dev = dev_get_by_napi_id(skb_napi_id(skb));
  	if (orig_dev)
  		ts_pktinfo.if_index = orig_dev->ifindex;
  	rcu_read_unlock();
  
  	ts_pktinfo.pkt_length = skb->len - skb_mac_offset(skb);
  	put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_PKTINFO,
  		 sizeof(ts_pktinfo), &ts_pktinfo);
  }
  
  /*
   * 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);
  	int new_tstamp = sock_flag(sk, SOCK_TSTAMP_NEW);
  	struct scm_timestamping_internal tss;
  
  	int empty = 1, false_tstamp = 0;
  	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 == 0) {
  		__net_timestamp(skb);
  		false_tstamp = 1;
  	}
  
  	if (need_software_tstamp) {
  		if (!sock_flag(sk, SOCK_RCVTSTAMPNS)) {
  			if (new_tstamp) {
  				struct __kernel_sock_timeval tv;
  
  				skb_get_new_timestamp(skb, &tv);
  				put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_NEW,
  					 sizeof(tv), &tv);
  			} else {
  				struct __kernel_old_timeval tv;
  
  				skb_get_timestamp(skb, &tv);
  				put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_OLD,
  					 sizeof(tv), &tv);
  			}
  		} else {
  			if (new_tstamp) {
  				struct __kernel_timespec ts;
  
  				skb_get_new_timestampns(skb, &ts);
  				put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
  					 sizeof(ts), &ts);
  			} else {
  				struct timespec ts;
  
  				skb_get_timestampns(skb, &ts);
  				put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_OLD,
  					 sizeof(ts), &ts);
  			}
  		}
  	}
  
  	memset(&tss, 0, sizeof(tss));
  	if ((sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) &&
  	    ktime_to_timespec64_cond(skb->tstamp, tss.ts + 0))
  		empty = 0;
  	if (shhwtstamps &&
  	    (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
  	    !skb_is_swtx_tstamp(skb, false_tstamp) &&
  	    ktime_to_timespec64_cond(shhwtstamps->hwtstamp, tss.ts + 2)) {
  		empty = 0;
  		if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO) &&
  		    !skb_is_err_queue(skb))
  			put_ts_pktinfo(msg, skb);
  	}
  	if (!empty) {
  		if (sock_flag(sk, SOCK_TSTAMP_NEW))
  			put_cmsg_scm_timestamping64(msg, &tss);
  		else
  			put_cmsg_scm_timestamping(msg, &tss);
  
  		if (skb_is_err_queue(skb) && skb->len &&
  		    SKB_EXT_ERR(skb)->opt_stats)
  			put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS,
  				 skb->len, skb->data);
  	}
  }
  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 && SOCK_SKB_CB(skb)->dropcount)
  		put_cmsg(msg, SOL_SOCKET, SO_RXQ_OVFL,
  			sizeof(__u32), &SOCK_SKB_CB(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);
  
  INDIRECT_CALLABLE_DECLARE(int inet_recvmsg(struct socket *, struct msghdr *,
  					   size_t, int));
  INDIRECT_CALLABLE_DECLARE(int inet6_recvmsg(struct socket *, struct msghdr *,
  					    size_t, int));
  static inline int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
  				     int flags)
  {
  	return INDIRECT_CALL_INET(sock->ops->recvmsg, inet6_recvmsg,
  				  inet_recvmsg, sock, msg, msg_data_left(msg),
  				  flags);
  }
  
  /**
   *	sock_recvmsg - receive a message from @sock
   *	@sock: socket
   *	@msg: message to receive
   *	@flags: message flags
   *
   *	Receives @msg from @sock, passing through LSM. Returns the total number
   *	of bytes received, or an error.
   */
  int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags)
  {
  	int err = security_socket_recvmsg(sock, msg, msg_data_left(msg), flags);
  
  	return err ?: sock_recvmsg_nosec(sock, msg, flags);
  }
  EXPORT_SYMBOL(sock_recvmsg);
  
  /**
   *	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;
  
  	iov_iter_kvec(&msg->msg_iter, READ, vec, num, size);
  	set_fs(KERNEL_DS);
  	result = sock_recvmsg(sock, msg, flags);
  	set_fs(oldfs);
  	return result;
  }
  EXPORT_SYMBOL(kernel_recvmsg);
  
  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 generic_file_splice_read(file, ppos, pipe, len, flags);
  
  	return sock->ops->splice_read(sock, ppos, pipe, len, flags);
  }
  
  static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
  {
  	struct file *file = iocb->ki_filp;
  	struct socket *sock = file->private_data;
  	struct msghdr msg = {.msg_iter = *to,
  			     .msg_iocb = iocb};
  	ssize_t res;
  
  	if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT))
  		msg.msg_flags = MSG_DONTWAIT;
  
  	if (iocb->ki_pos != 0)
  		return -ESPIPE;
  
  	if (!iov_iter_count(to))	/* Match SYS5 behaviour */
  		return 0;
  
  	res = sock_recvmsg(sock, &msg, msg.msg_flags);
  	*to = msg.msg_iter;
  	return res;
  }
  
  static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
  {
  	struct file *file = iocb->ki_filp;
  	struct socket *sock = file->private_data;
  	struct msghdr msg = {.msg_iter = *from,
  			     .msg_iocb = iocb};
  	ssize_t res;
  
  	if (iocb->ki_pos != 0)
  		return -ESPIPE;
  
  	if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT))
  		msg.msg_flags = MSG_DONTWAIT;
  
  	if (sock->type == SOCK_SEQPACKET)
  		msg.msg_flags |= MSG_EOR;
  
  	res = sock_sendmsg(sock, &msg);
  	*from = msg.msg_iter;
  	return res;
  }
  
  /*
   * 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)
  		return err;
  
  	if (cmd == SIOCGIFCONF) {
  		struct ifconf ifc;
  		if (copy_from_user(&ifc, argp, sizeof(struct ifconf)))
  			return -EFAULT;
  		rtnl_lock();
  		err = dev_ifconf(net, &ifc, sizeof(struct ifreq));
  		rtnl_unlock();
  		if (!err && copy_to_user(argp, &ifc, sizeof(struct ifconf)))
  			err = -EFAULT;
  	} else {
  		struct ifreq ifr;
  		bool need_copyout;
  		if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
  			return -EFAULT;
  		err = dev_ioctl(net, cmd, &ifr, &need_copyout);
  		if (!err && need_copyout)
  			if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
  				return -EFAULT;
  	}
  	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.
   */
  
  /**
   *	get_net_ns - increment the refcount of the network namespace
   *	@ns: common namespace (net)
   *
   *	Returns the net's common namespace.
   */
  
  struct ns_common *get_net_ns(struct ns_common *ns)
  {
  	return &get_net(container_of(ns, struct net, ns))->ns;
  }
  EXPORT_SYMBOL_GPL(get_net_ns);
  
  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 (unlikely(cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15))) {
  		struct ifreq ifr;
  		bool need_copyout;
  		if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
  			return -EFAULT;
  		err = dev_ioctl(net, cmd, &ifr, &need_copyout);
  		if (!err && need_copyout)
  			if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
  				return -EFAULT;
  	} else
  #ifdef CONFIG_WEXT_CORE
  	if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {
  		err = wext_handle_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;
  		case SIOCGSKNS:
  			err = -EPERM;
  			if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
  				break;
  
  			err = open_related_ns(&net->ns, get_net_ns);
  			break;
  		case SIOCGSTAMP_OLD:
  		case SIOCGSTAMPNS_OLD:
  			if (!sock->ops->gettstamp) {
  				err = -ENOIOCTLCMD;
  				break;
  			}
  			err = sock->ops->gettstamp(sock, argp,
  						   cmd == SIOCGSTAMP_OLD,
  						   !IS_ENABLED(CONFIG_64BIT));
  			break;
  		case SIOCGSTAMP_NEW:
  		case SIOCGSTAMPNS_NEW:
  			if (!sock->ops->gettstamp) {
  				err = -ENOIOCTLCMD;
  				break;
  			}
  			err = sock->ops->gettstamp(sock, argp,
  						   cmd == SIOCGSTAMP_NEW,
  						   false);
  			break;
  		default:
  			err = sock_do_ioctl(net, sock, cmd, arg);
  			break;
  		}
  	return err;
  }
  
  /**
   *	sock_create_lite - creates a socket
   *	@family: protocol family (AF_INET, ...)
   *	@type: communication type (SOCK_STREAM, ...)
   *	@protocol: protocol (0, ...)
   *	@res: new socket
   *
   *	Creates a new socket and assigns it to @res, passing through LSM.
   *	The new socket initialization is not complete, see kernel_accept().
   *	Returns 0 or an error. On failure @res is set to %NULL.
   *	This function internally uses GFP_KERNEL.
   */
  
  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 __poll_t sock_poll(struct file *file, poll_table *wait)
  {
  	struct socket *sock = file->private_data;
  	__poll_t events = poll_requested_events(wait), flag = 0;
  
  	if (!sock->ops->poll)
  		return 0;
  
  	if (sk_can_busy_loop(sock->sk)) {
  		/* poll once if requested by the syscall */
  		if (events & POLL_BUSY_LOOP)
  			sk_busy_loop(sock->sk, 1);
  
  		/* if this socket can poll_ll, tell the system call */
  		flag = POLL_BUSY_LOOP;
  	}
  
  	return sock->ops->poll(file, sock, wait) | flag;
  }
  
  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)
  {
  	__sock_release(SOCKET_I(inode), 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 = &sock->wq;
  
  	if (sk == NULL)
  		return -EINVAL;
  
  	lock_sock(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 rcu_lock */
  
  int sock_wake_async(struct socket_wq *wq, int how, int band)
  {
  	if (!wq || !wq->fasync_list)
  		return -1;
  
  	switch (how) {
  	case SOCK_WAKE_WAITD:
  		if (test_bit(SOCKWQ_ASYNC_WAITDATA, &wq->flags))
  			break;
  		goto call_kill;
  	case SOCK_WAKE_SPACE:
  		if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &wq->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);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL(sock_wake_async);
  
  /**
   *	__sock_create - creates a socket
   *	@net: net namespace
   *	@family: protocol family (AF_INET, ...)
   *	@type: communication type (SOCK_STREAM, ...)
   *	@protocol: protocol (0, ...)
   *	@res: new socket
   *	@kern: boolean for kernel space sockets
   *
   *	Creates a new socket and assigns it to @res, passing through LSM.
   *	Returns 0 or an error. On failure @res is set to %NULL. @kern must
   *	be set to true if the socket resides in kernel space.
   *	This function internally uses GFP_KERNEL.
   */
  
  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) {
  		pr_info_once("%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);
  
  /**
   *	sock_create - creates a socket
   *	@family: protocol family (AF_INET, ...)
   *	@type: communication type (SOCK_STREAM, ...)
   *	@protocol: protocol (0, ...)
   *	@res: new socket
   *
   *	A wrapper around __sock_create().
   *	Returns 0 or an error. This function internally uses GFP_KERNEL.
   */
  
  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);
  
  /**
   *	sock_create_kern - creates a socket (kernel space)
   *	@net: net namespace
   *	@family: protocol family (AF_INET, ...)
   *	@type: communication type (SOCK_STREAM, ...)
   *	@protocol: protocol (0, ...)
   *	@res: new socket
   *
   *	A wrapper around __sock_create().
   *	Returns 0 or an error. This function internally uses GFP_KERNEL.
   */
  
  int sock_create_kern(struct net *net, int family, int type, int protocol, struct socket **res)
  {
  	return __sock_create(net, family, type, protocol, res, 1);
  }
  EXPORT_SYMBOL(sock_create_kern);
  
  int __sys_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)
  		return retval;
  
  	return sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));
  }
  
  SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
  {
  	return __sys_socket(family, type, protocol);
  }
  
  /*
   *	Create a pair of connected sockets.
   */
  
  int __sys_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;
  
  	/*
  	 * reserve descriptors and make sure we won't fail
  	 * to return them to userland.
  	 */
  	fd1 = get_unused_fd_flags(flags);
  	if (unlikely(fd1 < 0))
  		return fd1;
  
  	fd2 = get_unused_fd_flags(flags);
  	if (unlikely(fd2 < 0)) {
  		put_unused_fd(fd1);
  		return fd2;
  	}
  
  	err = put_user(fd1, &usockvec[0]);
  	if (err)
  		goto out;
  
  	err = put_user(fd2, &usockvec[1]);
  	if (err)
  		goto out;
  
  	/*
  	 * Obtain the first socket and check if the underlying protocol
  	 * supports the socketpair call.
  	 */
  
  	err = sock_create(family, type, protocol, &sock1);
  	if (unlikely(err < 0))
  		goto out;
  
  	err = sock_create(family, type, protocol, &sock2);
  	if (unlikely(err < 0)) {
  		sock_release(sock1);
  		goto out;
  	}
  
  	err = security_socket_socketpair(sock1, sock2);
  	if (unlikely(err)) {
  		sock_release(sock2);
  		sock_release(sock1);
  		goto out;
  	}
  
  	err = sock1->ops->socketpair(sock1, sock2);
  	if (unlikely(err < 0)) {
  		sock_release(sock2);
  		sock_release(sock1);
  		goto out;
  	}
  
  	newfile1 = sock_alloc_file(sock1, flags, NULL);
  	if (IS_ERR(newfile1)) {
  		err = PTR_ERR(newfile1);
  		sock_release(sock2);
  		goto out;
  	}
  
  	newfile2 = sock_alloc_file(sock2, flags, NULL);
  	if (IS_ERR(newfile2)) {
  		err = PTR_ERR(newfile2);
  		fput(newfile1);
  		goto out;
  	}
  
  	audit_fd_pair(fd1, fd2);
  
  	fd_install(fd1, newfile1);
  	fd_install(fd2, newfile2);
  	return 0;
  
  out:
  	put_unused_fd(fd2);
  	put_unused_fd(fd1);
  	return err;
  }
  
  SYSCALL_DEFINE4(socketpair, int, family, int, type, int, protocol,
  		int __user *, usockvec)
  {
  	return __sys_socketpair(family, type, protocol, usockvec);
  }
  
  /*
   *	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).
   */
  
  int __sys_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) {
  			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;
  }
  
  SYSCALL_DEFINE3(bind, int, fd, struct sockaddr __user *, umyaddr, int, addrlen)
  {
  	return __sys_bind(fd, umyaddr, addrlen);
  }
  
  /*
   *	Perform a listen. Basically, we allow the protocol to do anything
   *	necessary for a listen, and if that works, we mark the socket as
   *	ready for listening.
   */
  
  int __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_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;
  }
  
  SYSCALL_DEFINE2(listen, int, fd, int, backlog)
  {
  	return __sys_listen(fd, backlog);
  }
  
  /*
   *	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 restructure accept also.
   */
  
  int __sys_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 (IS_ERR(newfile)) {
  		err = PTR_ERR(newfile);
  		put_unused_fd(newfd);
  		goto out_put;
  	}
  
  	err = security_socket_accept(sock, newsock);
  	if (err)
  		goto out_fd;
  
  	err = sock->ops->accept(sock, newsock, sock->file->f_flags, false);
  	if (err < 0)
  		goto out_fd;
  
  	if (upeer_sockaddr) {
  		len = newsock->ops->getname(newsock,
  					(struct sockaddr *)&address, 2);
  		if (len < 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_DEFINE4(accept4, int, fd, struct sockaddr __user *, upeer_sockaddr,
  		int __user *, upeer_addrlen, int, flags)
  {
  	return __sys_accept4(fd, upeer_sockaddr, upeer_addrlen, flags);
  }
  
  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.
   */
  
  int __sys_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;
  }
  
  SYSCALL_DEFINE3(connect, int, fd, struct sockaddr __user *, uservaddr,
  		int, addrlen)
  {
  	return __sys_connect(fd, uservaddr, addrlen);
  }
  
  /*
   *	Get the local address ('name') of a socket object. Move the obtained
   *	name to user space.
   */
  
  int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,
  		      int __user *usockaddr_len)
  {
  	struct socket *sock;
  	struct sockaddr_storage address;
  	int 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, 0);
  	if (err < 0)
  		goto out_put;
          /* "err" is actually length in this case */
  	err = move_addr_to_user(&address, err, usockaddr, usockaddr_len);
  
  out_put:
  	fput_light(sock->file, fput_needed);
  out:
  	return err;
  }
  
  SYSCALL_DEFINE3(getsockname, int, fd, struct sockaddr __user *, usockaddr,
  		int __user *, usockaddr_len)
  {
  	return __sys_getsockname(fd, usockaddr, usockaddr_len);
  }
  
  /*
   *	Get the remote address ('name') of a socket object. Move the obtained
   *	name to user space.
   */
  
  int __sys_getpeername(int fd, struct sockaddr __user *usockaddr,
  		      int __user *usockaddr_len)
  {
  	struct socket *sock;
  	struct sockaddr_storage address;
  	int 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, 1);
  		if (err >= 0)
  			/* "err" is actually length in this case */
  			err = move_addr_to_user(&address, err, usockaddr,
  						usockaddr_len);
  		fput_light(sock->file, fput_needed);
  	}
  	return err;
  }
  
  SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr,
  		int __user *, usockaddr_len)
  {
  	return __sys_getpeername(fd, usockaddr, usockaddr_len);
  }
  
  /*
   *	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.
   */
  int __sys_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;
  
  	err = import_single_range(WRITE, buff, len, &iov, &msg.msg_iter);
  	if (unlikely(err))
  		return err;
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (!sock)
  		goto out;
  
  	msg.msg_name = NULL;
  	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);
  
  out_put:
  	fput_light(sock->file, fput_needed);
  out:
  	return err;
  }
  
  SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len,
  		unsigned int, flags, struct sockaddr __user *, addr,
  		int, addr_len)
  {
  	return __sys_sendto(fd, buff, len, flags, addr, addr_len);
  }
  
  /*
   *	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.
   */
  int __sys_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;
  
  	err = import_single_range(READ, ubuf, size, &iov, &msg.msg_iter);
  	if (unlikely(err))
  		return err;
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (!sock)
  		goto out;
  
  	msg.msg_control = NULL;
  	msg.msg_controllen = 0;
  	/* Save some cycles and don't copy the address if not needed */
  	msg.msg_name = addr ? (struct sockaddr *)&address : NULL;
  	/* We assume all kernel code knows the size of sockaddr_storage */
  	msg.msg_namelen = 0;
  	msg.msg_iocb = NULL;
  	msg.msg_flags = 0;
  	if (sock->file->f_flags & O_NONBLOCK)
  		flags |= MSG_DONTWAIT;
  	err = sock_recvmsg(sock, &msg, 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;
  }
  
  SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
  		unsigned int, flags, struct sockaddr __user *, addr,
  		int __user *, addr_len)
  {
  	return __sys_recvfrom(fd, ubuf, size, flags, addr, addr_len);
  }
  
  /*
   *	Receive a datagram from a socket.
   */
  
  SYSCALL_DEFINE4(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.
   */
  
  static int __sys_setsockopt(int fd, int level, int optname,
  			    char __user *optval, int optlen)
  {
  	mm_segment_t oldfs = get_fs();
  	char *kernel_optval = NULL;
  	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;
  
  		err = BPF_CGROUP_RUN_PROG_SETSOCKOPT(sock->sk, &level,
  						     &optname, optval, &optlen,
  						     &kernel_optval);
  
  		if (err < 0) {
  			goto out_put;
  		} else if (err > 0) {
  			err = 0;
  			goto out_put;
  		}
  
  		if (kernel_optval) {
  			set_fs(KERNEL_DS);
  			optval = (char __user __force *)kernel_optval;
  		}
  
  		if (level == SOL_SOCKET)
  			err =
  			    sock_setsockopt(sock, level, optname, optval,
  					    optlen);
  		else
  			err =
  			    sock->ops->setsockopt(sock, level, optname, optval,
  						  optlen);
  
  		if (kernel_optval) {
  			set_fs(oldfs);
  			kfree(kernel_optval);
  		}
  out_put:
  		fput_light(sock->file, fput_needed);
  	}
  	return err;
  }
  
  SYSCALL_DEFINE5(setsockopt, int, fd, int, level, int, optname,
  		char __user *, optval, int, optlen)
  {
  	return __sys_setsockopt(fd, level, optname, optval, optlen);
  }
  
  /*
   *	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.
   */
  
  static int __sys_getsockopt(int fd, int level, int optname,
  			    char __user *optval, int __user *optlen)
  {
  	int err, fput_needed;
  	struct socket *sock;
  	int max_optlen;
  
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (sock != NULL) {
  		err = security_socket_getsockopt(sock, level, optname);
  		if (err)
  			goto out_put;
  
  		max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
  
  		if (level == SOL_SOCKET)
  			err =
  			    sock_getsockopt(sock, level, optname, optval,
  					    optlen);
  		else
  			err =
  			    sock->ops->getsockopt(sock, level, optname, optval,
  						  optlen);
  
  		err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname,
  						     optval, optlen,
  						     max_optlen, err);
  out_put:
  		fput_light(sock->file, fput_needed);
  	}
  	return err;
  }
  
  SYSCALL_DEFINE5(getsockopt, int, fd, int, level, int, optname,
  		char __user *, optval, int __user *, optlen)
  {
  	return __sys_getsockopt(fd, level, optname, optval, optlen);
  }
  
  /*
   *	Shutdown a socket.
   */
  
  int __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;
  }
  
  SYSCALL_DEFINE2(shutdown, int, fd, int, how)
  {
  	return __sys_shutdown(fd, how);
  }
  
  /* 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 copy_msghdr_from_user(struct msghdr *kmsg,
  				 struct user_msghdr __user *umsg,
  				 struct sockaddr __user **save_addr,
  				 struct iovec **iov)
  {
  	struct user_msghdr msg;
  	ssize_t err;
  
  	if (copy_from_user(&msg, umsg, sizeof(*umsg)))
  		return -EFAULT;
  
  	kmsg->msg_control = (void __force *)msg.msg_control;
  	kmsg->msg_controllen = msg.msg_controllen;
  	kmsg->msg_flags = msg.msg_flags;
  
  	kmsg->msg_namelen = msg.msg_namelen;
  	if (!msg.msg_name)
  		kmsg->msg_namelen = 0;
  
  	if (kmsg->msg_namelen < 0)
  		return -EINVAL;
  
  	if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
  		kmsg->msg_namelen = sizeof(struct sockaddr_storage);
  
  	if (save_addr)
  		*save_addr = msg.msg_name;
  
  	if (msg.msg_name && kmsg->msg_namelen) {
  		if (!save_addr) {
  			err = move_addr_to_kernel(msg.msg_name,
  						  kmsg->msg_namelen,
  						  kmsg->msg_name);
  			if (err < 0)
  				return err;
  		}
  	} else {
  		kmsg->msg_name = NULL;
  		kmsg->msg_namelen = 0;
  	}
  
  	if (msg.msg_iovlen > UIO_MAXIOV)
  		return -EMSGSIZE;
  
  	kmsg->msg_iocb = NULL;
  
  	err = import_iovec(save_addr ? READ : WRITE,
  			    msg.msg_iov, msg.msg_iovlen,
  			    UIO_FASTIOV, iov, &kmsg->msg_iter);
  	return err < 0 ? err : 0;
  }
  
  static int ____sys_sendmsg(struct socket *sock, struct msghdr *msg_sys,
  			   unsigned int flags, struct used_address *used_address,
  			   unsigned int allowed_msghdr_flags)
  {
  	unsigned char ctl[sizeof(struct cmsghdr) + 20]
  				__aligned(sizeof(__kernel_size_t));
  	/* 20 is size of ipv6_pktinfo */
  	unsigned char *ctl_buf = ctl;
  	int ctl_len;
  	ssize_t err;
  
  	err = -ENOBUFS;
  
  	if (msg_sys->msg_controllen > INT_MAX)
  		goto out;
  	flags |= (msg_sys->msg_flags & allowed_msghdr_flags);
  	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;
  		ctl_buf = msg_sys->msg_control;
  		ctl_len = msg_sys->msg_controllen;
  	} else if (ctl_len) {
  		BUILD_BUG_ON(sizeof(struct cmsghdr) !=
  			     CMSG_ALIGN(sizeof(struct cmsghdr)));
  		if (ctl_len > sizeof(ctl)) {
  			ctl_buf = sock_kmalloc(sock->sk, ctl_len, GFP_KERNEL);
  			if (ctl_buf == NULL)
  				goto out;
  		}
  		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 __force *)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;
  	/*
  	 * If this is sendmmsg() and current destination address is same as
  	 * previously succeeded address, omit asking LSM's decision.
  	 * used_address->name_len is initialized to UINT_MAX so that the first
  	 * destination address never matches.
  	 */
  	if (used_address && msg_sys->msg_name &&
  	    used_address->name_len == msg_sys->msg_namelen &&
  	    !memcmp(&used_address->name, msg_sys->msg_name,
  		    used_address->name_len)) {
  		err = sock_sendmsg_nosec(sock, msg_sys);
  		goto out_freectl;
  	}
  	err = sock_sendmsg(sock, msg_sys);
  	/*
  	 * If this is sendmmsg() and sending to current destination address was
  	 * successful, remember it.
  	 */
  	if (used_address && err >= 0) {
  		used_address->name_len = msg_sys->msg_namelen;
  		if (msg_sys->msg_name)
  			memcpy(&used_address->name, msg_sys->msg_name,
  			       used_address->name_len);
  	}
  
  out_freectl:
  	if (ctl_buf != ctl)
  		sock_kfree_s(sock->sk, ctl_buf, ctl_len);
  out:
  	return err;
  }
  
  static int sendmsg_copy_msghdr(struct msghdr *msg,
  			       struct user_msghdr __user *umsg, unsigned flags,
  			       struct iovec **iov)
  {
  	int err;
  
  	if (flags & MSG_CMSG_COMPAT) {
  		struct compat_msghdr __user *msg_compat;
  
  		msg_compat = (struct compat_msghdr __user *) umsg;
  		err = get_compat_msghdr(msg, msg_compat, NULL, iov);
  	} else {
  		err = copy_msghdr_from_user(msg, umsg, NULL, iov);
  	}
  	if (err < 0)
  		return err;
  
  	return 0;
  }
  
  static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
  			 struct msghdr *msg_sys, unsigned int flags,
  			 struct used_address *used_address,
  			 unsigned int allowed_msghdr_flags)
  {
  	struct sockaddr_storage address;
  	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
  	ssize_t err;
  
  	msg_sys->msg_name = &address;
  
  	err = sendmsg_copy_msghdr(msg_sys, msg, flags, &iov);
  	if (err < 0)
  		return err;
  
  	err = ____sys_sendmsg(sock, msg_sys, flags, used_address,
  				allowed_msghdr_flags);
  	kfree(iov);
  	return err;
  }
  
  /*
   *	BSD sendmsg interface
   */
  long __sys_sendmsg_sock(struct socket *sock, struct user_msghdr __user *umsg,
  			unsigned int flags)
  {
  	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
  	struct sockaddr_storage address;
  	struct msghdr msg = { .msg_name = &address };
  	ssize_t err;
  
  	err = sendmsg_copy_msghdr(&msg, umsg, flags, &iov);
  	if (err)
  		return err;
  	/* disallow ancillary data requests from this path */
  	if (msg.msg_control || msg.msg_controllen) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	err = ____sys_sendmsg(sock, &msg, flags, NULL, 0);
  out:
  	kfree(iov);
  	return err;
  }
  
  long __sys_sendmsg(int fd, struct user_msghdr __user *msg, unsigned int flags,
  		   bool forbid_cmsg_compat)
  {
  	int fput_needed, err;
  	struct msghdr msg_sys;
  	struct socket *sock;
  
  	if (forbid_cmsg_compat && (flags & MSG_CMSG_COMPAT))
  		return -EINVAL;
  
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (!sock)
  		goto out;
  
  	err = ___sys_sendmsg(sock, msg, &msg_sys, flags, NULL, 0);
  
  	fput_light(sock->file, fput_needed);
  out:
  	return err;
  }
  
  SYSCALL_DEFINE3(sendmsg, int, fd, struct user_msghdr __user *, msg, unsigned int, flags)
  {
  	return __sys_sendmsg(fd, msg, flags, true);
  }
  
  /*
   *	Linux sendmmsg interface
   */
  
  int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
  		   unsigned int flags, bool forbid_cmsg_compat)
  {
  	int fput_needed, err, datagrams;
  	struct socket *sock;
  	struct mmsghdr __user *entry;
  	struct compat_mmsghdr __user *compat_entry;
  	struct msghdr msg_sys;
  	struct used_address used_address;
  	unsigned int oflags = flags;
  
  	if (forbid_cmsg_compat && (flags & MSG_CMSG_COMPAT))
  		return -EINVAL;
  
  	if (vlen > UIO_MAXIOV)
  		vlen = UIO_MAXIOV;
  
  	datagrams = 0;
  
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (!sock)
  		return err;
  
  	used_address.name_len = UINT_MAX;
  	entry = mmsg;
  	compat_entry = (struct compat_mmsghdr __user *)mmsg;
  	err = 0;
  	flags |= MSG_BATCH;
  
  	while (datagrams < vlen) {
  		if (datagrams == vlen - 1)
  			flags = oflags;
  
  		if (MSG_CMSG_COMPAT & flags) {
  			err = ___sys_sendmsg(sock, (struct user_msghdr __user *)compat_entry,
  					     &msg_sys, flags, &used_address, MSG_EOR);
  			if (err < 0)
  				break;
  			err = __put_user(err, &compat_entry->msg_len);
  			++compat_entry;
  		} else {
  			err = ___sys_sendmsg(sock,
  					     (struct user_msghdr __user *)entry,
  					     &msg_sys, flags, &used_address, MSG_EOR);
  			if (err < 0)
  				break;
  			err = put_user(err, &entry->msg_len);
  			++entry;
  		}
  
  		if (err)
  			break;
  		++datagrams;
  		if (msg_data_left(&msg_sys))
  			break;
  		cond_resched();
  	}
  
  	fput_light(sock->file, fput_needed);
  
  	/* We only return an error if no datagrams were able to be sent */
  	if (datagrams != 0)
  		return datagrams;
  
  	return err;
  }
  
  SYSCALL_DEFINE4(sendmmsg, int, fd, struct mmsghdr __user *, mmsg,
  		unsigned int, vlen, unsigned int, flags)
  {
  	return __sys_sendmmsg(fd, mmsg, vlen, flags, true);
  }
  
  static int recvmsg_copy_msghdr(struct msghdr *msg,
  			       struct user_msghdr __user *umsg, unsigned flags,
  			       struct sockaddr __user **uaddr,
  			       struct iovec **iov)
  {
  	ssize_t err;
  
  	if (MSG_CMSG_COMPAT & flags) {
  		struct compat_msghdr __user *msg_compat;
  
  		msg_compat = (struct compat_msghdr __user *) umsg;
  		err = get_compat_msghdr(msg, msg_compat, uaddr, iov);
  	} else {
  		err = copy_msghdr_from_user(msg, umsg, uaddr, iov);
  	}
  	if (err < 0)
  		return err;
  
  	return 0;
  }
  
  static int ____sys_recvmsg(struct socket *sock, struct msghdr *msg_sys,
  			   struct user_msghdr __user *msg,
  			   struct sockaddr __user *uaddr,
  			   unsigned int flags, int nosec)
  {
  	struct compat_msghdr __user *msg_compat =
  					(struct compat_msghdr __user *) msg;
  	int __user *uaddr_len = COMPAT_NAMELEN(msg);
  	struct sockaddr_storage addr;
  	unsigned long cmsg_ptr;
  	int len;
  	ssize_t err;
  
  	msg_sys->msg_name = &addr;
  	cmsg_ptr = (unsigned long)msg_sys->msg_control;
  	msg_sys->msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
  
  	/* We assume all kernel code knows the size of sockaddr_storage */
  	msg_sys->msg_namelen = 0;
  
  	if (sock->file->f_flags & O_NONBLOCK)
  		flags |= MSG_DONTWAIT;
  	err = (nosec ? sock_recvmsg_nosec : sock_recvmsg)(sock, msg_sys, flags);
  	if (err < 0)
  		goto out;
  	len = err;
  
  	if (uaddr != NULL) {
  		err = move_addr_to_user(&addr,
  					msg_sys->msg_namelen, uaddr,
  					uaddr_len);
  		if (err < 0)
  			goto out;
  	}
  	err = __put_user((msg_sys->msg_flags & ~MSG_CMSG_COMPAT),
  			 COMPAT_FLAGS(msg));
  	if (err)
  		goto out;
  	if (MSG_CMSG_COMPAT & flags)
  		err = __put_user((unsigned long)msg_sys->msg_control - cmsg_ptr,
  				 &msg_compat->msg_controllen);
  	else
  		err = __put_user((unsigned long)msg_sys->msg_control - cmsg_ptr,
  				 &msg->msg_controllen);
  	if (err)
  		goto out;
  	err = len;
  out:
  	return err;
  }
  
  static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
  			 struct msghdr *msg_sys, unsigned int flags, int nosec)
  {
  	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
  	/* user mode address pointers */
  	struct sockaddr __user *uaddr;
  	ssize_t err;
  
  	err = recvmsg_copy_msghdr(msg_sys, msg, flags, &uaddr, &iov);
  	if (err < 0)
  		return err;
  
  	err = ____sys_recvmsg(sock, msg_sys, msg, uaddr, flags, nosec);
  	kfree(iov);
  	return err;
  }
  
  /*
   *	BSD recvmsg interface
   */
  
  long __sys_recvmsg_sock(struct socket *sock, struct user_msghdr __user *umsg,
  			unsigned int flags)
  {
  	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
  	struct sockaddr_storage address;
  	struct msghdr msg = { .msg_name = &address };
  	struct sockaddr __user *uaddr;
  	ssize_t err;
  
  	err = recvmsg_copy_msghdr(&msg, umsg, flags, &uaddr, &iov);
  	if (err)
  		return err;
  	/* disallow ancillary data requests from this path */
  	if (msg.msg_control || msg.msg_controllen) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	err = ____sys_recvmsg(sock, &msg, umsg, uaddr, flags, 0);
  out:
  	kfree(iov);
  	return err;
  }
  
  long __sys_recvmsg(int fd, struct user_msghdr __user *msg, unsigned int flags,
  		   bool forbid_cmsg_compat)
  {
  	int fput_needed, err;
  	struct msghdr msg_sys;
  	struct socket *sock;
  
  	if (forbid_cmsg_compat && (flags & MSG_CMSG_COMPAT))
  		return -EINVAL;
  
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (!sock)
  		goto out;
  
  	err = ___sys_recvmsg(sock, msg, &msg_sys, flags, 0);
  
  	fput_light(sock->file, fput_needed);
  out:
  	return err;
  }
  
  SYSCALL_DEFINE3(recvmsg, int, fd, struct user_msghdr __user *, msg,
  		unsigned int, flags)
  {
  	return __sys_recvmsg(fd, msg, flags, true);
  }
  
  /*
   *     Linux recvmmsg interface
   */
  
  static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg,
  			  unsigned int vlen, unsigned int flags,
  			  struct timespec64 *timeout)
  {
  	int fput_needed, err, datagrams;
  	struct socket *sock;
  	struct mmsghdr __user *entry;
  	struct compat_mmsghdr __user *compat_entry;
  	struct msghdr msg_sys;
  	struct timespec64 end_time;
  	struct timespec64 timeout64;
  
  	if (timeout &&
  	    poll_select_set_timeout(&end_time, timeout->tv_sec,
  				    timeout->tv_nsec))
  		return -EINVAL;
  
  	datagrams = 0;
  
  	sock = sockfd_lookup_light(fd, &err, &fput_needed);
  	if (!sock)
  		return err;
  
  	if (likely(!(flags & MSG_ERRQUEUE))) {
  		err = sock_error(sock->sk);
  		if (err) {
  			datagrams = err;
  			goto out_put;
  		}
  	}
  
  	entry = mmsg;
  	compat_entry = (struct compat_mmsghdr __user *)mmsg;
  
  	while (datagrams < vlen) {
  		/*
  		 * No need to ask LSM for more than the first datagram.
  		 */
  		if (MSG_CMSG_COMPAT & flags) {
  			err = ___sys_recvmsg(sock, (struct user_msghdr __user *)compat_entry,
  					     &msg_sys, flags & ~MSG_WAITFORONE,
  					     datagrams);
  			if (err < 0)
  				break;
  			err = __put_user(err, &compat_entry->msg_len);
  			++compat_entry;
  		} else {
  			err = ___sys_recvmsg(sock,
  					     (struct user_msghdr __user *)entry,
  					     &msg_sys, flags & ~MSG_WAITFORONE,
  					     datagrams);
  			if (err < 0)
  				break;
  			err = put_user(err, &entry->msg_len);
  			++entry;
  		}
  
  		if (err)
  			break;
  		++datagrams;
  
  		/* MSG_WAITFORONE turns on MSG_DONTWAIT after one packet */
  		if (flags & MSG_WAITFORONE)
  			flags |= MSG_DONTWAIT;
  
  		if (timeout) {
  			ktime_get_ts64(&timeout64);
  			*timeout = timespec64_sub(end_time, timeout64);
  			if (timeout->tv_sec < 0) {
  				timeout->tv_sec = timeout->tv_nsec = 0;
  				break;
  			}
  
  			/* Timeout, return less than vlen datagrams */
  			if (timeout->tv_nsec == 0 && timeout->tv_sec == 0)
  				break;
  		}
  
  		/* Out of band data, return right away */
  		if (msg_sys.msg_flags & MSG_OOB)
  			break;
  		cond_resched();
  	}
  
  	if (err == 0)
  		goto out_put;
  
  	if (datagrams == 0) {
  		datagrams = err;
  		goto out_put;
  	}
  
  	/*
  	 * We may return less entries than requested (vlen) if the
  	 * sock is non block and there aren't enough datagrams...
  	 */
  	if (err != -EAGAIN) {
  		/*
  		 * ... or  if recvmsg returns an error after we
  		 * received some datagrams, where we record the
  		 * error to return on the next call or if the
  		 * app asks about it using getsockopt(SO_ERROR).
  		 */
  		sock->sk->sk_err = -err;
  	}
  out_put:
  	fput_light(sock->file, fput_needed);
  
  	return datagrams;
  }
  
  int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg,
  		   unsigned int vlen, unsigned int flags,
  		   struct __kernel_timespec __user *timeout,
  		   struct old_timespec32 __user *timeout32)
  {
  	int datagrams;
  	struct timespec64 timeout_sys;
  
  	if (timeout && get_timespec64(&timeout_sys, timeout))
  		return -EFAULT;
  
  	if (timeout32 && get_old_timespec32(&timeout_sys, timeout32))
  		return -EFAULT;
  
  	if (!timeout && !timeout32)
  		return do_recvmmsg(fd, mmsg, vlen, flags, NULL);
  
  	datagrams = do_recvmmsg(fd, mmsg, vlen, flags, &timeout_sys);
  
  	if (datagrams <= 0)
  		return datagrams;
  
  	if (timeout && put_timespec64(&timeout_sys, timeout))
  		datagrams = -EFAULT;
  
  	if (timeout32 && put_old_timespec32(&timeout_sys, timeout32))
  		datagrams = -EFAULT;
  
  	return datagrams;
  }
  
  SYSCALL_DEFINE5(recvmmsg, int, fd, struct mmsghdr __user *, mmsg,
  		unsigned int, vlen, unsigned int, flags,
  		struct __kernel_timespec __user *, timeout)
  {
  	if (flags & MSG_CMSG_COMPAT)
  		return -EINVAL;
  
  	return __sys_recvmmsg(fd, mmsg, vlen, flags, timeout, NULL);
  }
  
  #ifdef CONFIG_COMPAT_32BIT_TIME
  SYSCALL_DEFINE5(recvmmsg_time32, int, fd, struct mmsghdr __user *, mmsg,
  		unsigned int, vlen, unsigned int, flags,
  		struct old_timespec32 __user *, timeout)
  {
  	if (flags & MSG_CMSG_COMPAT)
  		return -EINVAL;
  
  	return __sys_recvmmsg(fd, mmsg, vlen, flags, NULL, timeout);
  }
  #endif
  
  #ifdef __ARCH_WANT_SYS_SOCKETCALL
  /* Argument list sizes for sys_socketcall */
  #define AL(x) ((x) * sizeof(unsigned long))
  static const unsigned char nargs[21] = {
  	AL(0), AL(3), AL(3), AL(3), AL(2), AL(3),
  	AL(3), AL(3), AL(4), AL(4), AL(4), AL(6),
  	AL(6), AL(2), AL(5), AL(5), AL(3), AL(3),
  	AL(4), AL(5), AL(4)
  };
  
  #undef AL
  
  /*
   *	System call vectors.
   *
   *	Argument checking cleaned up. Saved 20% in size.
   *  This function doesn't need to set the kernel lock because
   *  it is set by the callees.
   */
  
  SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args)
  {
  	unsigned long a[AUDITSC_ARGS];
  	unsigned long a0, a1;
  	int err;
  	unsigned int len;
  
  	if (call < 1 || call > SYS_SENDMMSG)
  		return -EINVAL;
  	call = array_index_nospec(call, SYS_SENDMMSG + 1);
  
  	len = nargs[call];
  	if (len > sizeof(a))
  		return -EINVAL;
  
  	/* copy_from_user should be SMP safe. */
  	if (copy_from_user(a, args, len))
  		return -EFAULT;
  
  	err = audit_socketcall(nargs[call] / sizeof(unsigned long), a);
  	if (err)
  		return err;
  
  	a0 = a[0];
  	a1 = a[1];
  
  	switch (call) {
  	case SYS_SOCKET:
  		err = __sys_socket(a0, a1, a[2]);
  		break;
  	case SYS_BIND:
  		err = __sys_bind(a0, (struct sockaddr __user *)a1, a[2]);
  		break;
  	case SYS_CONNECT:
  		err = __sys_connect(a0, (struct sockaddr __user *)a1, a[2]);
  		break;
  	case SYS_LISTEN:
  		err = __sys_listen(a0, a1);
  		break;
  	case SYS_ACCEPT:
  		err = __sys_accept4(a0, (struct sockaddr __user *)a1,
  				    (int __user *)a[2], 0);
  		break;
  	case SYS_GETSOCKNAME:
  		err =
  		    __sys_getsockname(a0, (struct sockaddr __user *)a1,
  				      (int __user *)a[2]);
  		break;
  	case SYS_GETPEERNAME:
  		err =
  		    __sys_getpeername(a0, (struct sockaddr __user *)a1,
  				      (int __user *)a[2]);
  		break;
  	case SYS_SOCKETPAIR:
  		err = __sys_socketpair(a0, a1, a[2], (int __user *)a[3]);
  		break;
  	case SYS_SEND:
  		err = __sys_sendto(a0, (void __user *)a1, a[2], a[3],
  				   NULL, 0);
  		break;
  	case SYS_SENDTO:
  		err = __sys_sendto(a0, (void __user *)a1, a[2], a[3],
  				   (struct sockaddr __user *)a[4], a[5]);
  		break;
  	case SYS_RECV:
  		err = __sys_recvfrom(a0, (void __user *)a1, a[2], a[3],
  				     NULL, NULL);
  		break;
  	case SYS_RECVFROM:
  		err = __sys_recvfrom(a0, (void __user *)a1, a[2], a[3],
  				     (struct sockaddr __user *)a[4],
  				     (int __user *)a[5]);
  		break;
  	case SYS_SHUTDOWN:
  		err = __sys_shutdown(a0, a1);
  		break;
  	case SYS_SETSOCKOPT:
  		err = __sys_setsockopt(a0, a1, a[2], (char __user *)a[3],
  				       a[4]);
  		break;
  	case SYS_GETSOCKOPT:
  		err =
  		    __sys_getsockopt(a0, a1, a[2], (char __user *)a[3],
  				     (int __user *)a[4]);
  		break;
  	case SYS_SENDMSG:
  		err = __sys_sendmsg(a0, (struct user_msghdr __user *)a1,
  				    a[2], true);
  		break;
  	case SYS_SENDMMSG:
  		err = __sys_sendmmsg(a0, (struct mmsghdr __user *)a1, a[2],
  				     a[3], true);
  		break;
  	case SYS_RECVMSG:
  		err = __sys_recvmsg(a0, (struct user_msghdr __user *)a1,
  				    a[2], true);
  		break;
  	case SYS_RECVMMSG:
  		if (IS_ENABLED(CONFIG_64BIT) || !IS_ENABLED(CONFIG_64BIT_TIME))
  			err = __sys_recvmmsg(a0, (struct mmsghdr __user *)a1,
  					     a[2], a[3],
  					     (struct __kernel_timespec __user *)a[4],
  					     NULL);
  		else
  			err = __sys_recvmmsg(a0, (struct mmsghdr __user *)a1,
  					     a[2], a[3], NULL,
  					     (struct old_timespec32 __user *)a[4]);
  		break;
  	case SYS_ACCEPT4:
  		err = __sys_accept4(a0, (struct sockaddr __user *)a1,
  				    (int __user *)a[2], a[3]);
  		break;
  	default:
  		err = -EINVAL;
  		break;
  	}
  	return err;
  }
  
  #endif				/* __ARCH_WANT_SYS_SOCKETCALL */
  
  /**
   *	sock_register - add a socket protocol handler
   *	@ops: description of protocol
   *
   *	This function is called by a protocol handler that wants to
   *	advertise its address family, and have it linked into the
   *	socket interface. The value ops->family corresponds to the
   *	socket system call protocol family.
   */
  int sock_register(const struct net_proto_family *ops)
  {
  	int err;
  
  	if (ops->family >= NPROTO) {
  		pr_crit("protocol %d >= NPROTO(%d)\n", ops->family, NPROTO);
  		return -ENOBUFS;
  	}
  
  	spin_lock(&net_family_lock);
  	if (rcu_dereference_protected(net_families[ops->family],
  				      lockdep_is_held(&net_family_lock)))
  		err = -EEXIST;
  	else {
  		rcu_assign_pointer(net_families[ops->family], ops);
  		err = 0;
  	}
  	spin_unlock(&net_family_lock);
  
  	pr_info("NET: Registered protocol family %d\n", ops->family);
  	return err;
  }
  EXPORT_SYMBOL(sock_register);
  
  /**
   *	sock_unregister - remove a protocol handler
   *	@family: protocol family to remove
   *
   *	This function is called by a protocol handler that wants to
   *	remove its address family, and have it unlinked from the
   *	new socket creation.
   *
   *	If protocol handler is a module, then it can use module reference
   *	counts to protect against new references. If protocol handler is not
   *	a module then it needs to provide its own protection in
   *	the ops->create routine.
   */
  void sock_unregister(int family)
  {
  	BUG_ON(family < 0 || family >= NPROTO);
  
  	spin_lock(&net_family_lock);
  	RCU_INIT_POINTER(net_families[family], NULL);
  	spin_unlock(&net_family_lock);
  
  	synchronize_rcu();
  
  	pr_info("NET: Unregistered protocol family %d\n", family);
  }
  EXPORT_SYMBOL(sock_unregister);
  
  bool sock_is_registered(int family)
  {
  	return family < NPROTO && rcu_access_pointer(net_families[family]);
  }
  
  static int __init sock_init(void)
  {
  	int err;
  	/*
  	 *      Initialize the network sysctl infrastructure.
  	 */
  	err = net_sysctl_init();
  	if (err)
  		goto out;
  
  	/*
  	 *      Initialize skbuff SLAB cache
  	 */
  	skb_init();
  
  	/*
  	 *      Initialize the protocols module.
  	 */
  
  	init_inodecache();
  
  	err = register_filesystem(&sock_fs_type);
  	if (err)
  		goto out_fs;
  	sock_mnt = kern_mount(&sock_fs_type);
  	if (IS_ERR(sock_mnt)) {
  		err = PTR_ERR(sock_mnt);
  		goto out_mount;
  	}
  
  	/* The real protocol initialization is performed in later initcalls.
  	 */
  
  #ifdef CONFIG_NETFILTER
  	err = netfilter_init();
  	if (err)
  		goto out;
  #endif
  
  	ptp_classifier_init();
  
  out:
  	return err;
  
  out_mount:
  	unregister_filesystem(&sock_fs_type);
  out_fs:
  	goto out;
  }
  
  core_initcall(sock_init);	/* early initcall */
  
  #ifdef CONFIG_PROC_FS
  void socket_seq_show(struct seq_file *seq)
  {
  	seq_printf(seq, "sockets: used %d\n",
  		   sock_inuse_get(seq->private));
  }
  #endif				/* CONFIG_PROC_FS */
  
  #ifdef CONFIG_COMPAT
  static int compat_dev_ifconf(struct net *net, struct compat_ifconf __user *uifc32)
  {
  	struct compat_ifconf ifc32;
  	struct ifconf ifc;
  	int err;
  
  	if (copy_from_user(&ifc32, uifc32, sizeof(struct compat_ifconf)))
  		return -EFAULT;
  
  	ifc.ifc_len = ifc32.ifc_len;
  	ifc.ifc_req = compat_ptr(ifc32.ifcbuf);
  
  	rtnl_lock();
  	err = dev_ifconf(net, &ifc, sizeof(struct compat_ifreq));
  	rtnl_unlock();
  	if (err)
  		return err;
  
  	ifc32.ifc_len = ifc.ifc_len;
  	if (copy_to_user(uifc32, &ifc32, sizeof(struct compat_ifconf)))
  		return -EFAULT;
  
  	return 0;
  }
  
  static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32)
  {
  	struct compat_ethtool_rxnfc __user *compat_rxnfc;
  	bool convert_in = false, convert_out = false;
  	size_t buf_size = 0;
  	struct ethtool_rxnfc __user *rxnfc = NULL;
  	struct ifreq ifr;
  	u32 rule_cnt = 0, actual_rule_cnt;
  	u32 ethcmd;
  	u32 data;
  	int ret;
  
  	if (get_user(data, &ifr32->ifr_ifru.ifru_data))
  		return -EFAULT;
  
  	compat_rxnfc = compat_ptr(data);
  
  	if (get_user(ethcmd, &compat_rxnfc->cmd))
  		return -EFAULT;
  
  	/* Most ethtool structures are defined without padding.
  	 * Unfortunately struct ethtool_rxnfc is an exception.
  	 */
  	switch (ethcmd) {
  	default:
  		break;
  	case ETHTOOL_GRXCLSRLALL:
  		/* Buffer size is variable */
  		if (get_user(rule_cnt, &compat_rxnfc->rule_cnt))
  			return -EFAULT;
  		if (rule_cnt > KMALLOC_MAX_SIZE / sizeof(u32))
  			return -ENOMEM;
  		buf_size += rule_cnt * sizeof(u32);
  		/* fall through */
  	case ETHTOOL_GRXRINGS:
  	case ETHTOOL_GRXCLSRLCNT:
  	case ETHTOOL_GRXCLSRULE:
  	case ETHTOOL_SRXCLSRLINS:
  		convert_out = true;
  		/* fall through */
  	case ETHTOOL_SRXCLSRLDEL:
  		buf_size += sizeof(struct ethtool_rxnfc);
  		convert_in = true;
  		rxnfc = compat_alloc_user_space(buf_size);
  		break;
  	}
  
  	if (copy_from_user(&ifr.ifr_name, &ifr32->ifr_name, IFNAMSIZ))
  		return -EFAULT;
  
  	ifr.ifr_data = convert_in ? rxnfc : (void __user *)compat_rxnfc;
  
  	if (convert_in) {
  		/* We expect there to be holes between fs.m_ext and
  		 * fs.ring_cookie and at the end of fs, but nowhere else.
  		 */
  		BUILD_BUG_ON(offsetof(struct compat_ethtool_rxnfc, fs.m_ext) +
  			     sizeof(compat_rxnfc->fs.m_ext) !=
  			     offsetof(struct ethtool_rxnfc, fs.m_ext) +
  			     sizeof(rxnfc->fs.m_ext));
  		BUILD_BUG_ON(
  			offsetof(struct compat_ethtool_rxnfc, fs.location) -
  			offsetof(struct compat_ethtool_rxnfc, fs.ring_cookie) !=
  			offsetof(struct ethtool_rxnfc, fs.location) -
  			offsetof(struct ethtool_rxnfc, fs.ring_cookie));
  
  		if (copy_in_user(rxnfc, compat_rxnfc,
  				 (void __user *)(&rxnfc->fs.m_ext + 1) -
  				 (void __user *)rxnfc) ||
  		    copy_in_user(&rxnfc->fs.ring_cookie,
  				 &compat_rxnfc->fs.ring_cookie,
  				 (void __user *)(&rxnfc->fs.location + 1) -
  				 (void __user *)&rxnfc->fs.ring_cookie))
  			return -EFAULT;
  		if (ethcmd == ETHTOOL_GRXCLSRLALL) {
  			if (put_user(rule_cnt, &rxnfc->rule_cnt))
  				return -EFAULT;
  		} else if (copy_in_user(&rxnfc->rule_cnt,
  					&compat_rxnfc->rule_cnt,
  					sizeof(rxnfc->rule_cnt)))
  			return -EFAULT;
  	}
  
  	ret = dev_ioctl(net, SIOCETHTOOL, &ifr, NULL);
  	if (ret)
  		return ret;
  
  	if (convert_out) {
  		if (copy_in_user(compat_rxnfc, rxnfc,
  				 (const void __user *)(&rxnfc->fs.m_ext + 1) -
  				 (const void __user *)rxnfc) ||
  		    copy_in_user(&compat_rxnfc->fs.ring_cookie,
  				 &rxnfc->fs.ring_cookie,
  				 (const void __user *)(&rxnfc->fs.location + 1) -
  				 (const void __user *)&rxnfc->fs.ring_cookie) ||
  		    copy_in_user(&compat_rxnfc->rule_cnt, &rxnfc->rule_cnt,
  				 sizeof(rxnfc->rule_cnt)))
  			return -EFAULT;
  
  		if (ethcmd == ETHTOOL_GRXCLSRLALL) {
  			/* As an optimisation, we only copy the actual
  			 * number of rules that the underlying
  			 * function returned.  Since Mallory might
  			 * change the rule count in user memory, we
  			 * check that it is less than the rule count
  			 * originally given (as the user buffer size),
  			 * which has been range-checked.
  			 */
  			if (get_user(actual_rule_cnt, &rxnfc->rule_cnt))
  				return -EFAULT;
  			if (actual_rule_cnt < rule_cnt)
  				rule_cnt = actual_rule_cnt;
  			if (copy_in_user(&compat_rxnfc->rule_locs[0],
  					 &rxnfc->rule_locs[0],
  					 rule_cnt * sizeof(u32)))
  				return -EFAULT;
  		}
  	}
  
  	return 0;
  }
  
  static int compat_siocwandev(struct net *net, struct compat_ifreq __user *uifr32)
  {
  	compat_uptr_t uptr32;
  	struct ifreq ifr;
  	void __user *saved;
  	int err;
  
  	if (copy_from_user(&ifr, uifr32, sizeof(struct compat_ifreq)))
  		return -EFAULT;
  
  	if (get_user(uptr32, &uifr32->ifr_settings.ifs_ifsu))
  		return -EFAULT;
  
  	saved = ifr.ifr_settings.ifs_ifsu.raw_hdlc;
  	ifr.ifr_settings.ifs_ifsu.raw_hdlc = compat_ptr(uptr32);
  
  	err = dev_ioctl(net, SIOCWANDEV, &ifr, NULL);
  	if (!err) {
  		ifr.ifr_settings.ifs_ifsu.raw_hdlc = saved;
  		if (copy_to_user(uifr32, &ifr, sizeof(struct compat_ifreq)))
  			err = -EFAULT;
  	}
  	return err;
  }
  
  /* Handle ioctls that use ifreq::ifr_data and just need struct ifreq converted */
  static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd,
  				 struct compat_ifreq __user *u_ifreq32)
  {
  	struct ifreq ifreq;
  	u32 data32;
  
  	if (copy_from_user(ifreq.ifr_name, u_ifreq32->ifr_name, IFNAMSIZ))
  		return -EFAULT;
  	if (get_user(data32, &u_ifreq32->ifr_data))
  		return -EFAULT;
  	ifreq.ifr_data = compat_ptr(data32);
  
  	return dev_ioctl(net, cmd, &ifreq, NULL);
  }
  
  static int compat_ifreq_ioctl(struct net *net, struct socket *sock,
  			      unsigned int cmd,
  			      struct compat_ifreq __user *uifr32)
  {
  	struct ifreq __user *uifr;
  	int err;
  
  	/* Handle the fact that while struct ifreq has the same *layout* on
  	 * 32/64 for everything but ifreq::ifru_ifmap and ifreq::ifru_data,
  	 * which are handled elsewhere, it still has different *size* due to
  	 * ifreq::ifru_ifmap (which is 16 bytes on 32 bit, 24 bytes on 64-bit,
  	 * resulting in struct ifreq being 32 and 40 bytes respectively).
  	 * As a result, if the struct happens to be at the end of a page and
  	 * the next page isn't readable/writable, we get a fault. To prevent
  	 * that, copy back and forth to the full size.
  	 */
  
  	uifr = compat_alloc_user_space(sizeof(*uifr));
  	if (copy_in_user(uifr, uifr32, sizeof(*uifr32)))
  		return -EFAULT;
  
  	err = sock_do_ioctl(net, sock, cmd, (unsigned long)uifr);
  
  	if (!err) {
  		switch (cmd) {
  		case SIOCGIFFLAGS:
  		case SIOCGIFMETRIC:
  		case SIOCGIFMTU:
  		case SIOCGIFMEM:
  		case SIOCGIFHWADDR:
  		case SIOCGIFINDEX:
  		case SIOCGIFADDR:
  		case SIOCGIFBRDADDR:
  		case SIOCGIFDSTADDR:
  		case SIOCGIFNETMASK:
  		case SIOCGIFPFLAGS:
  		case SIOCGIFTXQLEN:
  		case SIOCGMIIPHY:
  		case SIOCGMIIREG:
  		case SIOCGIFNAME:
  			if (copy_in_user(uifr32, uifr, sizeof(*uifr32)))
  				err = -EFAULT;
  			break;
  		}
  	}
  	return err;
  }
  
  static int compat_sioc_ifmap(struct net *net, unsigned int cmd,
  			struct compat_ifreq __user *uifr32)
  {
  	struct ifreq ifr;
  	struct compat_ifmap __user *uifmap32;
  	int err;
  
  	uifmap32 = &uifr32->ifr_ifru.ifru_map;
  	err = copy_from_user(&ifr, uifr32, sizeof(ifr.ifr_name));
  	err |= get_user(ifr.ifr_map.mem_start, &uifmap32->mem_start);
  	err |= get_user(ifr.ifr_map.mem_end, &uifmap32->mem_end);
  	err |= get_user(ifr.ifr_map.base_addr, &uifmap32->base_addr);
  	err |= get_user(ifr.ifr_map.irq, &uifmap32->irq);
  	err |= get_user(ifr.ifr_map.dma, &uifmap32->dma);
  	err |= get_user(ifr.ifr_map.port, &uifmap32->port);
  	if (err)
  		return -EFAULT;
  
  	err = dev_ioctl(net, cmd, &ifr, NULL);
  
  	if (cmd == SIOCGIFMAP && !err) {
  		err = copy_to_user(uifr32, &ifr, sizeof(ifr.ifr_name));
  		err |= put_user(ifr.ifr_map.mem_start, &uifmap32->mem_start);
  		err |= put_user(ifr.ifr_map.mem_end, &uifmap32->mem_end);
  		err |= put_user(ifr.ifr_map.base_addr, &uifmap32->base_addr);
  		err |= put_user(ifr.ifr_map.irq, &uifmap32->irq);
  		err |= put_user(ifr.ifr_map.dma, &uifmap32->dma);
  		err |= put_user(ifr.ifr_map.port, &uifmap32->port);
  		if (err)
  			err = -EFAULT;
  	}
  	return err;
  }
  
  struct rtentry32 {
  	u32		rt_pad1;
  	struct sockaddr rt_dst;         /* target address               */
  	struct sockaddr rt_gateway;     /* gateway addr (RTF_GATEWAY)   */
  	struct sockaddr rt_genmask;     /* target network mask (IP)     */
  	unsigned short	rt_flags;
  	short		rt_pad2;
  	u32		rt_pad3;
  	unsigned char	rt_tos;
  	unsigned char	rt_class;
  	short		rt_pad4;
  	short		rt_metric;      /* +1 for binary compatibility! */
  	/* char * */ u32 rt_dev;        /* forcing the device at add    */
  	u32		rt_mtu;         /* per route MTU/Window         */
  	u32		rt_window;      /* Window clamping              */
  	unsigned short  rt_irtt;        /* Initial RTT                  */
  };
  
  struct in6_rtmsg32 {
  	struct in6_addr		rtmsg_dst;
  	struct in6_addr		rtmsg_src;
  	struct in6_addr		rtmsg_gateway;
  	u32			rtmsg_type;
  	u16			rtmsg_dst_len;
  	u16			rtmsg_src_len;
  	u32			rtmsg_metric;
  	u32			rtmsg_info;
  	u32			rtmsg_flags;
  	s32			rtmsg_ifindex;
  };
  
  static int routing_ioctl(struct net *net, struct socket *sock,
  			 unsigned int cmd, void __user *argp)
  {
  	int ret;
  	void *r = NULL;
  	struct in6_rtmsg r6;
  	struct rtentry r4;
  	char devname[16];
  	u32 rtdev;
  	mm_segment_t old_fs = get_fs();
  
  	if (sock && sock->sk && sock->sk->sk_family == AF_INET6) { /* ipv6 */
  		struct in6_rtmsg32 __user *ur6 = argp;
  		ret = copy_from_user(&r6.rtmsg_dst, &(ur6->rtmsg_dst),
  			3 * sizeof(struct in6_addr));
  		ret |= get_user(r6.rtmsg_type, &(ur6->rtmsg_type));
  		ret |= get_user(r6.rtmsg_dst_len, &(ur6->rtmsg_dst_len));
  		ret |= get_user(r6.rtmsg_src_len, &(ur6->rtmsg_src_len));
  		ret |= get_user(r6.rtmsg_metric, &(ur6->rtmsg_metric));
  		ret |= get_user(r6.rtmsg_info, &(ur6->rtmsg_info));
  		ret |= get_user(r6.rtmsg_flags, &(ur6->rtmsg_flags));
  		ret |= get_user(r6.rtmsg_ifindex, &(ur6->rtmsg_ifindex));
  
  		r = (void *) &r6;
  	} else { /* ipv4 */
  		struct rtentry32 __user *ur4 = argp;
  		ret = copy_from_user(&r4.rt_dst, &(ur4->rt_dst),
  					3 * sizeof(struct sockaddr));
  		ret |= get_user(r4.rt_flags, &(ur4->rt_flags));
  		ret |= get_user(r4.rt_metric, &(ur4->rt_metric));
  		ret |= get_user(r4.rt_mtu, &(ur4->rt_mtu));
  		ret |= get_user(r4.rt_window, &(ur4->rt_window));
  		ret |= get_user(r4.rt_irtt, &(ur4->rt_irtt));
  		ret |= get_user(rtdev, &(ur4->rt_dev));
  		if (rtdev) {
  			ret |= copy_from_user(devname, compat_ptr(rtdev), 15);
  			r4.rt_dev = (char __user __force *)devname;
  			devname[15] = 0;
  		} else
  			r4.rt_dev = NULL;
  
  		r = (void *) &r4;
  	}
  
  	if (ret) {
  		ret = -EFAULT;
  		goto out;
  	}
  
  	set_fs(KERNEL_DS);
  	ret = sock_do_ioctl(net, sock, cmd, (unsigned long) r);
  	set_fs(old_fs);
  
  out:
  	return ret;
  }
  
  /* Since old style bridge ioctl's endup using SIOCDEVPRIVATE
   * for some operations; this forces use of the newer bridge-utils that
   * use compatible ioctls
   */
  static int old_bridge_ioctl(compat_ulong_t __user *argp)
  {
  	compat_ulong_t tmp;
  
  	if (get_user(tmp, argp))
  		return -EFAULT;
  	if (tmp == BRCTL_GET_VERSION)
  		return BRCTL_VERSION + 1;
  	return -EINVAL;
  }
  
  static int compat_sock_ioctl_trans(struct file *file, struct socket *sock,
  			 unsigned int cmd, unsigned long arg)
  {
  	void __user *argp = compat_ptr(arg);
  	struct sock *sk = sock->sk;
  	struct net *net = sock_net(sk);
  
  	if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15))
  		return compat_ifr_data_ioctl(net, cmd, argp);
  
  	switch (cmd) {
  	case SIOCSIFBR:
  	case SIOCGIFBR:
  		return old_bridge_ioctl(argp);
  	case SIOCGIFCONF:
  		return compat_dev_ifconf(net, argp);
  	case SIOCETHTOOL:
  		return ethtool_ioctl(net, argp);
  	case SIOCWANDEV:
  		return compat_siocwandev(net, argp);
  	case SIOCGIFMAP:
  	case SIOCSIFMAP:
  		return compat_sioc_ifmap(net, cmd, argp);
  	case SIOCADDRT:
  	case SIOCDELRT:
  		return routing_ioctl(net, sock, cmd, argp);
  	case SIOCGSTAMP_OLD:
  	case SIOCGSTAMPNS_OLD:
  		if (!sock->ops->gettstamp)
  			return -ENOIOCTLCMD;
  		return sock->ops->gettstamp(sock, argp, cmd == SIOCGSTAMP_OLD,
  					    !COMPAT_USE_64BIT_TIME);
  
  	case SIOCBONDSLAVEINFOQUERY:
  	case SIOCBONDINFOQUERY:
  	case SIOCSHWTSTAMP:
  	case SIOCGHWTSTAMP:
  		return compat_ifr_data_ioctl(net, cmd, argp);
  
  	case FIOSETOWN:
  	case SIOCSPGRP:
  	case FIOGETOWN:
  	case SIOCGPGRP:
  	case SIOCBRADDBR:
  	case SIOCBRDELBR:
  	case SIOCGIFVLAN:
  	case SIOCSIFVLAN:
  	case SIOCADDDLCI:
  	case SIOCDELDLCI:
  	case SIOCGSKNS:
  	case SIOCGSTAMP_NEW:
  	case SIOCGSTAMPNS_NEW:
  		return sock_ioctl(file, cmd, arg);
  
  	case SIOCGIFFLAGS:
  	case SIOCSIFFLAGS:
  	case SIOCGIFMETRIC:
  	case SIOCSIFMETRIC:
  	case SIOCGIFMTU:
  	case SIOCSIFMTU:
  	case SIOCGIFMEM:
  	case SIOCSIFMEM:
  	case SIOCGIFHWADDR:
  	case SIOCSIFHWADDR:
  	case SIOCADDMULTI:
  	case SIOCDELMULTI:
  	case SIOCGIFINDEX:
  	case SIOCGIFADDR:
  	case SIOCSIFADDR:
  	case SIOCSIFHWBROADCAST:
  	case SIOCDIFADDR:
  	case SIOCGIFBRDADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCGIFDSTADDR:
  	case SIOCSIFDSTADDR:
  	case SIOCGIFNETMASK:
  	case SIOCSIFNETMASK:
  	case SIOCSIFPFLAGS:
  	case SIOCGIFPFLAGS:
  	case SIOCGIFTXQLEN:
  	case SIOCSIFTXQLEN:
  	case SIOCBRADDIF:
  	case SIOCBRDELIF:
  	case SIOCGIFNAME:
  	case SIOCSIFNAME:
  	case SIOCGMIIPHY:
  	case SIOCGMIIREG:
  	case SIOCSMIIREG:
  	case SIOCBONDENSLAVE:
  	case SIOCBONDRELEASE:
  	case SIOCBONDSETHWADDR:
  	case SIOCBONDCHANGEACTIVE:
  		return compat_ifreq_ioctl(net, sock, cmd, argp);
  
  	case SIOCSARP:
  	case SIOCGARP:
  	case SIOCDARP:
  	case SIOCOUTQNSD:
  	case SIOCATMARK:
  		return sock_do_ioctl(net, sock, cmd, arg);
  	}
  
  	return -ENOIOCTLCMD;
  }
  
  static long compat_sock_ioctl(struct file *file, unsigned int cmd,
  			      unsigned long arg)
  {
  	struct socket *sock = file->private_data;
  	int ret = -ENOIOCTLCMD;
  	struct sock *sk;
  	struct net *net;
  
  	sk = sock->sk;
  	net = sock_net(sk);
  
  	if (sock->ops->compat_ioctl)
  		ret = sock->ops->compat_ioctl(sock, cmd, arg);
  
  	if (ret == -ENOIOCTLCMD &&
  	    (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST))
  		ret = compat_wext_handle_ioctl(net, cmd, arg);
  
  	if (ret == -ENOIOCTLCMD)
  		ret = compat_sock_ioctl_trans(file, sock, cmd, arg);
  
  	return ret;
  }
  #endif
  
  /**
   *	kernel_bind - bind an address to a socket (kernel space)
   *	@sock: socket
   *	@addr: address
   *	@addrlen: length of address
   *
   *	Returns 0 or an error.
   */
  
  int kernel_bind(struct socket *sock, struct sockaddr *addr, int addrlen)
  {
  	return sock->ops->bind(sock, addr, addrlen);
  }
  EXPORT_SYMBOL(kernel_bind);
  
  /**
   *	kernel_listen - move socket to listening state (kernel space)
   *	@sock: socket
   *	@backlog: pending connections queue size
   *
   *	Returns 0 or an error.
   */
  
  int kernel_listen(struct socket *sock, int backlog)
  {
  	return sock->ops->listen(sock, backlog);
  }
  EXPORT_SYMBOL(kernel_listen);
  
  /**
   *	kernel_accept - accept a connection (kernel space)
   *	@sock: listening socket
   *	@newsock: new connected socket
   *	@flags: flags
   *
   *	@flags must be SOCK_CLOEXEC, SOCK_NONBLOCK or 0.
   *	If it fails, @newsock is guaranteed to be %NULL.
   *	Returns 0 or an error.
   */
  
  int kernel_accept(struct socket *sock, struct socket **newsock, int flags)
  {
  	struct sock *sk = sock->sk;
  	int err;
  
  	err = sock_create_lite(sk->sk_family, sk->sk_type, sk->sk_protocol,
  			       newsock);
  	if (err < 0)
  		goto done;
  
  	err = sock->ops->accept(sock, *newsock, flags, true);
  	if (err < 0) {
  		sock_release(*newsock);
  		*newsock = NULL;
  		goto done;
  	}
  
  	(*newsock)->ops = sock->ops;
  	__module_get((*newsock)->ops->owner);
  
  done:
  	return err;
  }
  EXPORT_SYMBOL(kernel_accept);
  
  /**
   *	kernel_connect - connect a socket (kernel space)
   *	@sock: socket
   *	@addr: address
   *	@addrlen: address length
   *	@flags: flags (O_NONBLOCK, ...)
   *
   *	For datagram sockets, @addr is the addres to which datagrams are sent
   *	by default, and the only address from which datagrams are received.
   *	For stream sockets, attempts to connect to @addr.
   *	Returns 0 or an error code.
   */
  
  int kernel_connect(struct socket *sock, struct sockaddr *addr, int addrlen,
  		   int flags)
  {
  	return sock->ops->connect(sock, addr, addrlen, flags);
  }
  EXPORT_SYMBOL(kernel_connect);
  
  /**
   *	kernel_getsockname - get the address which the socket is bound (kernel space)
   *	@sock: socket
   *	@addr: address holder
   *
   * 	Fills the @addr pointer with the address which the socket is bound.
   *	Returns 0 or an error code.
   */
  
  int kernel_getsockname(struct socket *sock, struct sockaddr *addr)
  {
  	return sock->ops->getname(sock, addr, 0);
  }
  EXPORT_SYMBOL(kernel_getsockname);
  
  /**
   *	kernel_peername - get the address which the socket is connected (kernel space)
   *	@sock: socket
   *	@addr: address holder
   *
   * 	Fills the @addr pointer with the address which the socket is connected.
   *	Returns 0 or an error code.
   */
  
  int kernel_getpeername(struct socket *sock, struct sockaddr *addr)
  {
  	return sock->ops->getname(sock, addr, 1);
  }
  EXPORT_SYMBOL(kernel_getpeername);
  
  /**
   *	kernel_getsockopt - get a socket option (kernel space)
   *	@sock: socket
   *	@level: API level (SOL_SOCKET, ...)
   *	@optname: option tag
   *	@optval: option value
   *	@optlen: option length
   *
   *	Assigns the option length to @optlen.
   *	Returns 0 or an error.
   */
  
  int kernel_getsockopt(struct socket *sock, int level, int optname,
  			char *optval, int *optlen)
  {
  	mm_segment_t oldfs = get_fs();
  	char __user *uoptval;
  	int __user *uoptlen;
  	int err;
  
  	uoptval = (char __user __force *) optval;
  	uoptlen = (int __user __force *) optlen;
  
  	set_fs(KERNEL_DS);
  	if (level == SOL_SOCKET)
  		err = sock_getsockopt(sock, level, optname, uoptval, uoptlen);
  	else
  		err = sock->ops->getsockopt(sock, level, optname, uoptval,
  					    uoptlen);
  	set_fs(oldfs);
  	return err;
  }
  EXPORT_SYMBOL(kernel_getsockopt);
  
  /**
   *	kernel_setsockopt - set a socket option (kernel space)
   *	@sock: socket
   *	@level: API level (SOL_SOCKET, ...)
   *	@optname: option tag
   *	@optval: option value
   *	@optlen: option length
   *
   *	Returns 0 or an error.
   */
  
  int kernel_setsockopt(struct socket *sock, int level, int optname,
  			char *optval, unsigned int optlen)
  {
  	mm_segment_t oldfs = get_fs();
  	char __user *uoptval;
  	int err;
  
  	uoptval = (char __user __force *) optval;
  
  	set_fs(KERNEL_DS);
  	if (level == SOL_SOCKET)
  		err = sock_setsockopt(sock, level, optname, uoptval, optlen);
  	else
  		err = sock->ops->setsockopt(sock, level, optname, uoptval,
  					    optlen);
  	set_fs(oldfs);
  	return err;
  }
  EXPORT_SYMBOL(kernel_setsockopt);
  
  /**
   *	kernel_sendpage - send a &page through a socket (kernel space)
   *	@sock: socket
   *	@page: page
   *	@offset: page offset
   *	@size: total size in bytes
   *	@flags: flags (MSG_DONTWAIT, ...)
   *
   *	Returns the total amount sent in bytes or an error.
   */
  
  int kernel_sendpage(struct socket *sock, struct page *page, int offset,
  		    size_t size, int flags)
  {
  	if (sock->ops->sendpage)
  		return sock->ops->sendpage(sock, page, offset, size, flags);
  
  	return sock_no_sendpage(sock, page, offset, size, flags);
  }
  EXPORT_SYMBOL(kernel_sendpage);
  
  /**
   *	kernel_sendpage_locked - send a &page through the locked sock (kernel space)
   *	@sk: sock
   *	@page: page
   *	@offset: page offset
   *	@size: total size in bytes
   *	@flags: flags (MSG_DONTWAIT, ...)
   *
   *	Returns the total amount sent in bytes or an error.
   *	Caller must hold @sk.
   */
  
  int kernel_sendpage_locked(struct sock *sk, struct page *page, int offset,
  			   size_t size, int flags)
  {
  	struct socket *sock = sk->sk_socket;
  
  	if (sock->ops->sendpage_locked)
  		return sock->ops->sendpage_locked(sk, page, offset, size,
  						  flags);
  
  	return sock_no_sendpage_locked(sk, page, offset, size, flags);
  }
  EXPORT_SYMBOL(kernel_sendpage_locked);
  
  /**
   *	kernel_shutdown - shut down part of a full-duplex connection (kernel space)
   *	@sock: socket
   *	@how: connection part
   *
   *	Returns 0 or an error.
   */
  
  int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how)
  {
  	return sock->ops->shutdown(sock, how);
  }
  EXPORT_SYMBOL(kernel_sock_shutdown);
  
  /**
   *	kernel_sock_ip_overhead - returns the IP overhead imposed by a socket
   *	@sk: socket
   *
   *	This routine returns the IP overhead imposed by a socket i.e.
   *	the length of the underlying IP header, depending on whether
   *	this is an IPv4 or IPv6 socket and the length from IP options turned
   *	on at the socket. Assumes that the caller has a lock on the socket.
   */
  
  u32 kernel_sock_ip_overhead(struct sock *sk)
  {
  	struct inet_sock *inet;
  	struct ip_options_rcu *opt;
  	u32 overhead = 0;
  #if IS_ENABLED(CONFIG_IPV6)
  	struct ipv6_pinfo *np;
  	struct ipv6_txoptions *optv6 = NULL;
  #endif /* IS_ENABLED(CONFIG_IPV6) */
  
  	if (!sk)
  		return overhead;
  
  	switch (sk->sk_family) {
  	case AF_INET:
  		inet = inet_sk(sk);
  		overhead += sizeof(struct iphdr);
  		opt = rcu_dereference_protected(inet->inet_opt,
  						sock_owned_by_user(sk));
  		if (opt)
  			overhead += opt->opt.optlen;
  		return overhead;
  #if IS_ENABLED(CONFIG_IPV6)
  	case AF_INET6:
  		np = inet6_sk(sk);
  		overhead += sizeof(struct ipv6hdr);
  		if (np)
  			optv6 = rcu_dereference_protected(np->opt,
  							  sock_owned_by_user(sk));
  		if (optv6)
  			overhead += (optv6->opt_flen + optv6->opt_nflen);
  		return overhead;
  #endif /* IS_ENABLED(CONFIG_IPV6) */
  	default: /* Returns 0 overhead if the socket is not ipv4 or ipv6 */
  		return overhead;
  	}
  }
  EXPORT_SYMBOL(kernel_sock_ip_overhead);
  