text: /*
   * VMware vSockets Driver
   *
   * Copyright (C) 2007-2013 VMware, Inc. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation version 2 and no later version.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   */
  
  /* Implementation notes:
   *
   * - There are two kinds of sockets: those created by user action (such as
   * calling socket(2)) and those created by incoming connection request packets.
   *
   * - There are two "global" tables, one for bound sockets (sockets that have
   * specified an address that they are responsible for) and one for connected
   * sockets (sockets that have established a connection with another socket).
   * These tables are "global" in that all sockets on the system are placed
   * within them. - Note, though, that the bound table contains an extra entry
   * for a list of unbound sockets and SOCK_DGRAM sockets will always remain in
   * that list. The bound table is used solely for lookup of sockets when packets
   * are received and that's not necessary for SOCK_DGRAM sockets since we create
   * a datagram handle for each and need not perform a lookup.  Keeping SOCK_DGRAM
   * sockets out of the bound hash buckets will reduce the chance of collisions
   * when looking for SOCK_STREAM sockets and prevents us from having to check the
   * socket type in the hash table lookups.
   *
   * - Sockets created by user action will either be "client" sockets that
   * initiate a connection or "server" sockets that listen for connections; we do
   * not support simultaneous connects (two "client" sockets connecting).
   *
   * - "Server" sockets are referred to as listener sockets throughout this
   * implementation because they are in the SS_LISTEN state.  When a connection
   * request is received (the second kind of socket mentioned above), we create a
   * new socket and refer to it as a pending socket.  These pending sockets are
   * placed on the pending connection list of the listener socket.  When future
   * packets are received for the address the listener socket is bound to, we
   * check if the source of the packet is from one that has an existing pending
   * connection.  If it does, we process the packet for the pending socket.  When
   * that socket reaches the connected state, it is removed from the listener
   * socket's pending list and enqueued in the listener socket's accept queue.
   * Callers of accept(2) will accept connected sockets from the listener socket's
   * accept queue.  If the socket cannot be accepted for some reason then it is
   * marked rejected.  Once the connection is accepted, it is owned by the user
   * process and the responsibility for cleanup falls with that user process.
   *
   * - It is possible that these pending sockets will never reach the connected
   * state; in fact, we may never receive another packet after the connection
   * request.  Because of this, we must schedule a cleanup function to run in the
   * future, after some amount of time passes where a connection should have been
   * established.  This function ensures that the socket is off all lists so it
   * cannot be retrieved, then drops all references to the socket so it is cleaned
   * up (sock_put() -> sk_free() -> our sk_destruct implementation).  Note this
   * function will also cleanup rejected sockets, those that reach the connected
   * state but leave it before they have been accepted.
   *
   * - Sockets created by user action will be cleaned up when the user process
   * calls close(2), causing our release implementation to be called. Our release
   * implementation will perform some cleanup then drop the last reference so our
   * sk_destruct implementation is invoked.  Our sk_destruct implementation will
   * perform additional cleanup that's common for both types of sockets.
   *
   * - A socket's reference count is what ensures that the structure won't be
   * freed.  Each entry in a list (such as the "global" bound and connected tables
   * and the listener socket's pending list and connected queue) ensures a
   * reference.  When we defer work until process context and pass a socket as our
   * argument, we must ensure the reference count is increased to ensure the
   * socket isn't freed before the function is run; the deferred function will
   * then drop the reference.
   */
  
  #include <linux/types.h>
  #include <linux/bitops.h>
  #include <linux/cred.h>
  #include <linux/init.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/kmod.h>
  #include <linux/list.h>
  #include <linux/miscdevice.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/net.h>
  #include <linux/poll.h>
  #include <linux/skbuff.h>
  #include <linux/smp.h>
  #include <linux/socket.h>
  #include <linux/stddef.h>
  #include <linux/unistd.h>
  #include <linux/wait.h>
  #include <linux/workqueue.h>
  #include <net/sock.h>
  
  #include "af_vsock.h"
  
  static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
  static void vsock_sk_destruct(struct sock *sk);
  static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
  
  /* Protocol family. */
  static struct proto vsock_proto = {
  	.name = "AF_VSOCK",
  	.owner = THIS_MODULE,
  	.obj_size = sizeof(struct vsock_sock),
  };
  
  /* The default peer timeout indicates how long we will wait for a peer response
   * to a control message.
   */
  #define VSOCK_DEFAULT_CONNECT_TIMEOUT (2 * HZ)
  
  #define SS_LISTEN 255
  
  static const struct vsock_transport *transport;
  static DEFINE_MUTEX(vsock_register_mutex);
  
  /**** EXPORTS ****/
  
  /* Get the ID of the local context.  This is transport dependent. */
  
  int vm_sockets_get_local_cid(void)
  {
  	return transport->get_local_cid();
  }
  EXPORT_SYMBOL_GPL(vm_sockets_get_local_cid);
  
  /**** UTILS ****/
  
  /* Each bound VSocket is stored in the bind hash table and each connected
   * VSocket is stored in the connected hash table.
   *
   * Unbound sockets are all put on the same list attached to the end of the hash
   * table (vsock_unbound_sockets).  Bound sockets are added to the hash table in
   * the bucket that their local address hashes to (vsock_bound_sockets(addr)
   * represents the list that addr hashes to).
   *
   * Specifically, we initialize the vsock_bind_table array to a size of
   * VSOCK_HASH_SIZE + 1 so that vsock_bind_table[0] through
   * vsock_bind_table[VSOCK_HASH_SIZE - 1] are for bound sockets and
   * vsock_bind_table[VSOCK_HASH_SIZE] is for unbound sockets.  The hash function
   * mods with VSOCK_HASH_SIZE - 1 to ensure this.
   */
  #define VSOCK_HASH_SIZE         251
  #define MAX_PORT_RETRIES        24
  
  #define VSOCK_HASH(addr)        ((addr)->svm_port % (VSOCK_HASH_SIZE - 1))
  #define vsock_bound_sockets(addr) (&vsock_bind_table[VSOCK_HASH(addr)])
  #define vsock_unbound_sockets     (&vsock_bind_table[VSOCK_HASH_SIZE])
  
  /* XXX This can probably be implemented in a better way. */
  #define VSOCK_CONN_HASH(src, dst)				\
  	(((src)->svm_cid ^ (dst)->svm_port) % (VSOCK_HASH_SIZE - 1))
  #define vsock_connected_sockets(src, dst)		\
  	(&vsock_connected_table[VSOCK_CONN_HASH(src, dst)])
  #define vsock_connected_sockets_vsk(vsk)				\
  	vsock_connected_sockets(&(vsk)->remote_addr, &(vsk)->local_addr)
  
  static struct list_head vsock_bind_table[VSOCK_HASH_SIZE + 1];
  static struct list_head vsock_connected_table[VSOCK_HASH_SIZE];
  static DEFINE_SPINLOCK(vsock_table_lock);
  
  static void vsock_init_tables(void)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(vsock_bind_table); i++)
  		INIT_LIST_HEAD(&vsock_bind_table[i]);
  
  	for (i = 0; i < ARRAY_SIZE(vsock_connected_table); i++)
  		INIT_LIST_HEAD(&vsock_connected_table[i]);
  }
  
  static void __vsock_insert_bound(struct list_head *list,
  				 struct vsock_sock *vsk)
  {
  	sock_hold(&vsk->sk);
  	list_add(&vsk->bound_table, list);
  }
  
  static void __vsock_insert_connected(struct list_head *list,
  				     struct vsock_sock *vsk)
  {
  	sock_hold(&vsk->sk);
  	list_add(&vsk->connected_table, list);
  }
  
  static void __vsock_remove_bound(struct vsock_sock *vsk)
  {
  	list_del_init(&vsk->bound_table);
  	sock_put(&vsk->sk);
  }
  
  static void __vsock_remove_connected(struct vsock_sock *vsk)
  {
  	list_del_init(&vsk->connected_table);
  	sock_put(&vsk->sk);
  }
  
  static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
  {
  	struct vsock_sock *vsk;
  
  	list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table)
  		if (addr->svm_port == vsk->local_addr.svm_port)
  			return sk_vsock(vsk);
  
  	return NULL;
  }
  
  static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
  						  struct sockaddr_vm *dst)
  {
  	struct vsock_sock *vsk;
  
  	list_for_each_entry(vsk, vsock_connected_sockets(src, dst),
  			    connected_table) {
  		if (vsock_addr_equals_addr(src, &vsk->remote_addr) &&
  		    dst->svm_port == vsk->local_addr.svm_port) {
  			return sk_vsock(vsk);
  		}
  	}
  
  	return NULL;
  }
  
  static bool __vsock_in_bound_table(struct vsock_sock *vsk)
  {
  	return !list_empty(&vsk->bound_table);
  }
  
  static bool __vsock_in_connected_table(struct vsock_sock *vsk)
  {
  	return !list_empty(&vsk->connected_table);
  }
  
  static void vsock_insert_unbound(struct vsock_sock *vsk)
  {
  	spin_lock_bh(&vsock_table_lock);
  	__vsock_insert_bound(vsock_unbound_sockets, vsk);
  	spin_unlock_bh(&vsock_table_lock);
  }
  
  void vsock_insert_connected(struct vsock_sock *vsk)
  {
  	struct list_head *list = vsock_connected_sockets(
  		&vsk->remote_addr, &vsk->local_addr);
  
  	spin_lock_bh(&vsock_table_lock);
  	__vsock_insert_connected(list, vsk);
  	spin_unlock_bh(&vsock_table_lock);
  }
  EXPORT_SYMBOL_GPL(vsock_insert_connected);
  
  void vsock_remove_bound(struct vsock_sock *vsk)
  {
  	spin_lock_bh(&vsock_table_lock);
  	__vsock_remove_bound(vsk);
  	spin_unlock_bh(&vsock_table_lock);
  }
  EXPORT_SYMBOL_GPL(vsock_remove_bound);
  
  void vsock_remove_connected(struct vsock_sock *vsk)
  {
  	spin_lock_bh(&vsock_table_lock);
  	__vsock_remove_connected(vsk);
  	spin_unlock_bh(&vsock_table_lock);
  }
  EXPORT_SYMBOL_GPL(vsock_remove_connected);
  
  struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
  {
  	struct sock *sk;
  
  	spin_lock_bh(&vsock_table_lock);
  	sk = __vsock_find_bound_socket(addr);
  	if (sk)
  		sock_hold(sk);
  
  	spin_unlock_bh(&vsock_table_lock);
  
  	return sk;
  }
  EXPORT_SYMBOL_GPL(vsock_find_bound_socket);
  
  struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
  					 struct sockaddr_vm *dst)
  {
  	struct sock *sk;
  
  	spin_lock_bh(&vsock_table_lock);
  	sk = __vsock_find_connected_socket(src, dst);
  	if (sk)
  		sock_hold(sk);
  
  	spin_unlock_bh(&vsock_table_lock);
  
  	return sk;
  }
  EXPORT_SYMBOL_GPL(vsock_find_connected_socket);
  
  static bool vsock_in_bound_table(struct vsock_sock *vsk)
  {
  	bool ret;
  
  	spin_lock_bh(&vsock_table_lock);
  	ret = __vsock_in_bound_table(vsk);
  	spin_unlock_bh(&vsock_table_lock);
  
  	return ret;
  }
  
  static bool vsock_in_connected_table(struct vsock_sock *vsk)
  {
  	bool ret;
  
  	spin_lock_bh(&vsock_table_lock);
  	ret = __vsock_in_connected_table(vsk);
  	spin_unlock_bh(&vsock_table_lock);
  
  	return ret;
  }
  
  void vsock_for_each_connected_socket(void (*fn)(struct sock *sk))
  {
  	int i;
  
  	spin_lock_bh(&vsock_table_lock);
  
  	for (i = 0; i < ARRAY_SIZE(vsock_connected_table); i++) {
  		struct vsock_sock *vsk;
  		list_for_each_entry(vsk, &vsock_connected_table[i],
  				    connected_table);
  			fn(sk_vsock(vsk));
  	}
  
  	spin_unlock_bh(&vsock_table_lock);
  }
  EXPORT_SYMBOL_GPL(vsock_for_each_connected_socket);
  
  void vsock_add_pending(struct sock *listener, struct sock *pending)
  {
  	struct vsock_sock *vlistener;
  	struct vsock_sock *vpending;
  
  	vlistener = vsock_sk(listener);
  	vpending = vsock_sk(pending);
  
  	sock_hold(pending);
  	sock_hold(listener);
  	list_add_tail(&vpending->pending_links, &vlistener->pending_links);
  }
  EXPORT_SYMBOL_GPL(vsock_add_pending);
  
  void vsock_remove_pending(struct sock *listener, struct sock *pending)
  {
  	struct vsock_sock *vpending = vsock_sk(pending);
  
  	list_del_init(&vpending->pending_links);
  	sock_put(listener);
  	sock_put(pending);
  }
  EXPORT_SYMBOL_GPL(vsock_remove_pending);
  
  void vsock_enqueue_accept(struct sock *listener, struct sock *connected)
  {
  	struct vsock_sock *vlistener;
  	struct vsock_sock *vconnected;
  
  	vlistener = vsock_sk(listener);
  	vconnected = vsock_sk(connected);
  
  	sock_hold(connected);
  	sock_hold(listener);
  	list_add_tail(&vconnected->accept_queue, &vlistener->accept_queue);
  }
  EXPORT_SYMBOL_GPL(vsock_enqueue_accept);
  
  static struct sock *vsock_dequeue_accept(struct sock *listener)
  {
  	struct vsock_sock *vlistener;
  	struct vsock_sock *vconnected;
  
  	vlistener = vsock_sk(listener);
  
  	if (list_empty(&vlistener->accept_queue))
  		return NULL;
  
  	vconnected = list_entry(vlistener->accept_queue.next,
  				struct vsock_sock, accept_queue);
  
  	list_del_init(&vconnected->accept_queue);
  	sock_put(listener);
  	/* The caller will need a reference on the connected socket so we let
  	 * it call sock_put().
  	 */
  
  	return sk_vsock(vconnected);
  }
  
  static bool vsock_is_accept_queue_empty(struct sock *sk)
  {
  	struct vsock_sock *vsk = vsock_sk(sk);
  	return list_empty(&vsk->accept_queue);
  }
  
  static bool vsock_is_pending(struct sock *sk)
  {
  	struct vsock_sock *vsk = vsock_sk(sk);
  	return !list_empty(&vsk->pending_links);
  }
  
  static int vsock_send_shutdown(struct sock *sk, int mode)
  {
  	return transport->shutdown(vsock_sk(sk), mode);
  }
  
  void vsock_pending_work(struct work_struct *work)
  {
  	struct sock *sk;
  	struct sock *listener;
  	struct vsock_sock *vsk;
  	bool cleanup;
  
  	vsk = container_of(work, struct vsock_sock, dwork.work);
  	sk = sk_vsock(vsk);
  	listener = vsk->listener;
  	cleanup = true;
  
  	lock_sock(listener);
  	lock_sock(sk);
  
  	if (vsock_is_pending(sk)) {
  		vsock_remove_pending(listener, sk);
  	} else if (!vsk->rejected) {
  		/* We are not on the pending list and accept() did not reject
  		 * us, so we must have been accepted by our user process.  We
  		 * just need to drop our references to the sockets and be on
  		 * our way.
  		 */
  		cleanup = false;
  		goto out;
  	}
  
  	listener->sk_ack_backlog--;
  
  	/* We need to remove ourself from the global connected sockets list so
  	 * incoming packets can't find this socket, and to reduce the reference
  	 * count.
  	 */
  	if (vsock_in_connected_table(vsk))
  		vsock_remove_connected(vsk);
  
  	sk->sk_state = SS_FREE;
  
  out:
  	release_sock(sk);
  	release_sock(listener);
  	if (cleanup)
  		sock_put(sk);
  
  	sock_put(sk);
  	sock_put(listener);
  }
  EXPORT_SYMBOL_GPL(vsock_pending_work);
  
  /**** SOCKET OPERATIONS ****/
  
  static int __vsock_bind_stream(struct vsock_sock *vsk,
  			       struct sockaddr_vm *addr)
  {
  	static u32 port = LAST_RESERVED_PORT + 1;
  	struct sockaddr_vm new_addr;
  
  	vsock_addr_init(&new_addr, addr->svm_cid, addr->svm_port);
  
  	if (addr->svm_port == VMADDR_PORT_ANY) {
  		bool found = false;
  		unsigned int i;
  
  		for (i = 0; i < MAX_PORT_RETRIES; i++) {
  			if (port <= LAST_RESERVED_PORT)
  				port = LAST_RESERVED_PORT + 1;
  
  			new_addr.svm_port = port++;
  
  			if (!__vsock_find_bound_socket(&new_addr)) {
  				found = true;
  				break;
  			}
  		}
  
  		if (!found)
  			return -EADDRNOTAVAIL;
  	} else {
  		/* If port is in reserved range, ensure caller
  		 * has necessary privileges.
  		 */
  		if (addr->svm_port <= LAST_RESERVED_PORT &&
  		    !capable(CAP_NET_BIND_SERVICE)) {
  			return -EACCES;
  		}
  
  		if (__vsock_find_bound_socket(&new_addr))
  			return -EADDRINUSE;
  	}
  
  	vsock_addr_init(&vsk->local_addr, new_addr.svm_cid, new_addr.svm_port);
  
  	/* Remove stream sockets from the unbound list and add them to the hash
  	 * table for easy lookup by its address.  The unbound list is simply an
  	 * extra entry at the end of the hash table, a trick used by AF_UNIX.
  	 */
  	__vsock_remove_bound(vsk);
  	__vsock_insert_bound(vsock_bound_sockets(&vsk->local_addr), vsk);
  
  	return 0;
  }
  
  static int __vsock_bind_dgram(struct vsock_sock *vsk,
  			      struct sockaddr_vm *addr)
  {
  	return transport->dgram_bind(vsk, addr);
  }
  
  static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
  {
  	struct vsock_sock *vsk = vsock_sk(sk);
  	u32 cid;
  	int retval;
  
  	/* First ensure this socket isn't already bound. */
  	if (vsock_addr_bound(&vsk->local_addr))
  		return -EINVAL;
  
  	/* Now bind to the provided address or select appropriate values if
  	 * none are provided (VMADDR_CID_ANY and VMADDR_PORT_ANY).  Note that
  	 * like AF_INET prevents binding to a non-local IP address (in most
  	 * cases), we only allow binding to the local CID.
  	 */
  	cid = transport->get_local_cid();
  	if (addr->svm_cid != cid && addr->svm_cid != VMADDR_CID_ANY)
  		return -EADDRNOTAVAIL;
  
  	switch (sk->sk_socket->type) {
  	case SOCK_STREAM:
  		spin_lock_bh(&vsock_table_lock);
  		retval = __vsock_bind_stream(vsk, addr);
  		spin_unlock_bh(&vsock_table_lock);
  		break;
  
  	case SOCK_DGRAM:
  		retval = __vsock_bind_dgram(vsk, addr);
  		break;
  
  	default:
  		retval = -EINVAL;
  		break;
  	}
  
  	return retval;
  }
  
  struct sock *__vsock_create(struct net *net,
  			    struct socket *sock,
  			    struct sock *parent,
  			    gfp_t priority,
  			    unsigned short type)
  {
  	struct sock *sk;
  	struct vsock_sock *psk;
  	struct vsock_sock *vsk;
  
  	sk = sk_alloc(net, AF_VSOCK, priority, &vsock_proto);
  	if (!sk)
  		return NULL;
  
  	sock_init_data(sock, sk);
  
  	/* sk->sk_type is normally set in sock_init_data, but only if sock is
  	 * non-NULL. We make sure that our sockets always have a type by
  	 * setting it here if needed.
  	 */
  	if (!sock)
  		sk->sk_type = type;
  
  	vsk = vsock_sk(sk);
  	vsock_addr_init(&vsk->local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
  	vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
  
  	sk->sk_destruct = vsock_sk_destruct;
  	sk->sk_backlog_rcv = vsock_queue_rcv_skb;
  	sk->sk_state = 0;
  	sock_reset_flag(sk, SOCK_DONE);
  
  	INIT_LIST_HEAD(&vsk->bound_table);
  	INIT_LIST_HEAD(&vsk->connected_table);
  	vsk->listener = NULL;
  	INIT_LIST_HEAD(&vsk->pending_links);
  	INIT_LIST_HEAD(&vsk->accept_queue);
  	vsk->rejected = false;
  	vsk->sent_request = false;
  	vsk->ignore_connecting_rst = false;
  	vsk->peer_shutdown = 0;
  
  	psk = parent ? vsock_sk(parent) : NULL;
  	if (parent) {
  		vsk->trusted = psk->trusted;
  		vsk->owner = get_cred(psk->owner);
  		vsk->connect_timeout = psk->connect_timeout;
  	} else {
  		vsk->trusted = capable(CAP_NET_ADMIN);
  		vsk->owner = get_current_cred();
  		vsk->connect_timeout = VSOCK_DEFAULT_CONNECT_TIMEOUT;
  	}
  
  	if (transport->init(vsk, psk) < 0) {
  		sk_free(sk);
  		return NULL;
  	}
  
  	if (sock)
  		vsock_insert_unbound(vsk);
  
  	return sk;
  }
  EXPORT_SYMBOL_GPL(__vsock_create);
  
  static void __vsock_release(struct sock *sk)
  {
  	if (sk) {
  		struct sk_buff *skb;
  		struct sock *pending;
  		struct vsock_sock *vsk;
  
  		vsk = vsock_sk(sk);
  		pending = NULL;	/* Compiler warning. */
  
  		if (vsock_in_bound_table(vsk))
  			vsock_remove_bound(vsk);
  
  		if (vsock_in_connected_table(vsk))
  			vsock_remove_connected(vsk);
  
  		transport->release(vsk);
  
  		lock_sock(sk);
  		sock_orphan(sk);
  		sk->sk_shutdown = SHUTDOWN_MASK;
  
  		while ((skb = skb_dequeue(&sk->sk_receive_queue)))
  			kfree_skb(skb);
  
  		/* Clean up any sockets that never were accepted. */
  		while ((pending = vsock_dequeue_accept(sk)) != NULL) {
  			__vsock_release(pending);
  			sock_put(pending);
  		}
  
  		release_sock(sk);
  		sock_put(sk);
  	}
  }
  
  static void vsock_sk_destruct(struct sock *sk)
  {
  	struct vsock_sock *vsk = vsock_sk(sk);
  
  	transport->destruct(vsk);
  
  	/* When clearing these addresses, there's no need to set the family and
  	 * possibly register the address family with the kernel.
  	 */
  	vsock_addr_init(&vsk->local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
  	vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
  
  	put_cred(vsk->owner);
  }
  
  static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
  {
  	int err;
  
  	err = sock_queue_rcv_skb(sk, skb);
  	if (err)
  		kfree_skb(skb);
  
  	return err;
  }
  
  s64 vsock_stream_has_data(struct vsock_sock *vsk)
  {
  	return transport->stream_has_data(vsk);
  }
  EXPORT_SYMBOL_GPL(vsock_stream_has_data);
  
  s64 vsock_stream_has_space(struct vsock_sock *vsk)
  {
  	return transport->stream_has_space(vsk);
  }
  EXPORT_SYMBOL_GPL(vsock_stream_has_space);
  
  static int vsock_release(struct socket *sock)
  {
  	__vsock_release(sock->sk);
  	sock->sk = NULL;
  	sock->state = SS_FREE;
  
  	return 0;
  }
  
  static int
  vsock_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
  {
  	int err;
  	struct sock *sk;
  	struct sockaddr_vm *vm_addr;
  
  	sk = sock->sk;
  
  	if (vsock_addr_cast(addr, addr_len, &vm_addr) != 0)
  		return -EINVAL;
  
  	lock_sock(sk);
  	err = __vsock_bind(sk, vm_addr);
  	release_sock(sk);
  
  	return err;
  }
  
  static int vsock_getname(struct socket *sock,
  			 struct sockaddr *addr, int *addr_len, int peer)
  {
  	int err;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	struct sockaddr_vm *vm_addr;
  
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  	err = 0;
  
  	lock_sock(sk);
  
  	if (peer) {
  		if (sock->state != SS_CONNECTED) {
  			err = -ENOTCONN;
  			goto out;
  		}
  		vm_addr = &vsk->remote_addr;
  	} else {
  		vm_addr = &vsk->local_addr;
  	}
  
  	if (!vm_addr) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	/* sys_getsockname() and sys_getpeername() pass us a
  	 * MAX_SOCK_ADDR-sized buffer and don't set addr_len.  Unfortunately
  	 * that macro is defined in socket.c instead of .h, so we hardcode its
  	 * value here.
  	 */
  	BUILD_BUG_ON(sizeof(*vm_addr) > 128);
  	memcpy(addr, vm_addr, sizeof(*vm_addr));
  	*addr_len = sizeof(*vm_addr);
  
  out:
  	release_sock(sk);
  	return err;
  }
  
  static int vsock_shutdown(struct socket *sock, int mode)
  {
  	int err;
  	struct sock *sk;
  
  	/* User level uses SHUT_RD (0) and SHUT_WR (1), but the kernel uses
  	 * RCV_SHUTDOWN (1) and SEND_SHUTDOWN (2), so we must increment mode
  	 * here like the other address families do.  Note also that the
  	 * increment makes SHUT_RDWR (2) into RCV_SHUTDOWN | SEND_SHUTDOWN (3),
  	 * which is what we want.
  	 */
  	mode++;
  
  	if ((mode & ~SHUTDOWN_MASK) || !mode)
  		return -EINVAL;
  
  	/* If this is a STREAM socket and it is not connected then bail out
  	 * immediately.  If it is a DGRAM socket then we must first kick the
  	 * socket so that it wakes up from any sleeping calls, for example
  	 * recv(), and then afterwards return the error.
  	 */
  
  	sk = sock->sk;
  	if (sock->state == SS_UNCONNECTED) {
  		err = -ENOTCONN;
  		if (sk->sk_type == SOCK_STREAM)
  			return err;
  	} else {
  		sock->state = SS_DISCONNECTING;
  		err = 0;
  	}
  
  	/* Receive and send shutdowns are treated alike. */
  	mode = mode & (RCV_SHUTDOWN | SEND_SHUTDOWN);
  	if (mode) {
  		lock_sock(sk);
  		sk->sk_shutdown |= mode;
  		sk->sk_state_change(sk);
  		release_sock(sk);
  
  		if (sk->sk_type == SOCK_STREAM) {
  			sock_reset_flag(sk, SOCK_DONE);
  			vsock_send_shutdown(sk, mode);
  		}
  	}
  
  	return err;
  }
  
  static unsigned int vsock_poll(struct file *file, struct socket *sock,
  			       poll_table *wait)
  {
  	struct sock *sk;
  	unsigned int mask;
  	struct vsock_sock *vsk;
  
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  
  	poll_wait(file, sk_sleep(sk), wait);
  	mask = 0;
  
  	if (sk->sk_err)
  		/* Signify that there has been an error on this socket. */
  		mask |= POLLERR;
  
  	/* INET sockets treat local write shutdown and peer write shutdown as a
  	 * case of POLLHUP set.
  	 */
  	if ((sk->sk_shutdown == SHUTDOWN_MASK) ||
  	    ((sk->sk_shutdown & SEND_SHUTDOWN) &&
  	     (vsk->peer_shutdown & SEND_SHUTDOWN))) {
  		mask |= POLLHUP;
  	}
  
  	if (sk->sk_shutdown & RCV_SHUTDOWN ||
  	    vsk->peer_shutdown & SEND_SHUTDOWN) {
  		mask |= POLLRDHUP;
  	}
  
  	if (sock->type == SOCK_DGRAM) {
  		/* For datagram sockets we can read if there is something in
  		 * the queue and write as long as the socket isn't shutdown for
  		 * sending.
  		 */
  		if (!skb_queue_empty(&sk->sk_receive_queue) ||
  		    (sk->sk_shutdown & RCV_SHUTDOWN)) {
  			mask |= POLLIN | POLLRDNORM;
  		}
  
  		if (!(sk->sk_shutdown & SEND_SHUTDOWN))
  			mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
  
  	} else if (sock->type == SOCK_STREAM) {
  		lock_sock(sk);
  
  		/* Listening sockets that have connections in their accept
  		 * queue can be read.
  		 */
  		if (sk->sk_state == SS_LISTEN
  		    && !vsock_is_accept_queue_empty(sk))
  			mask |= POLLIN | POLLRDNORM;
  
  		/* If there is something in the queue then we can read. */
  		if (transport->stream_is_active(vsk) &&
  		    !(sk->sk_shutdown & RCV_SHUTDOWN)) {
  			bool data_ready_now = false;
  			int ret = transport->notify_poll_in(
  					vsk, 1, &data_ready_now);
  			if (ret < 0) {
  				mask |= POLLERR;
  			} else {
  				if (data_ready_now)
  					mask |= POLLIN | POLLRDNORM;
  
  			}
  		}
  
  		/* Sockets whose connections have been closed, reset, or
  		 * terminated should also be considered read, and we check the
  		 * shutdown flag for that.
  		 */
  		if (sk->sk_shutdown & RCV_SHUTDOWN ||
  		    vsk->peer_shutdown & SEND_SHUTDOWN) {
  			mask |= POLLIN | POLLRDNORM;
  		}
  
  		/* Connected sockets that can produce data can be written. */
  		if (sk->sk_state == SS_CONNECTED) {
  			if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
  				bool space_avail_now = false;
  				int ret = transport->notify_poll_out(
  						vsk, 1, &space_avail_now);
  				if (ret < 0) {
  					mask |= POLLERR;
  				} else {
  					if (space_avail_now)
  						/* Remove POLLWRBAND since INET
  						 * sockets are not setting it.
  						 */
  						mask |= POLLOUT | POLLWRNORM;
  
  				}
  			}
  		}
  
  		/* Simulate INET socket poll behaviors, which sets
  		 * POLLOUT|POLLWRNORM when peer is closed and nothing to read,
  		 * but local send is not shutdown.
  		 */
  		if (sk->sk_state == SS_UNCONNECTED) {
  			if (!(sk->sk_shutdown & SEND_SHUTDOWN))
  				mask |= POLLOUT | POLLWRNORM;
  
  		}
  
  		release_sock(sk);
  	}
  
  	return mask;
  }
  
  static int vsock_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
  			       struct msghdr *msg, size_t len)
  {
  	int err;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	struct sockaddr_vm *remote_addr;
  
  	if (msg->msg_flags & MSG_OOB)
  		return -EOPNOTSUPP;
  
  	/* For now, MSG_DONTWAIT is always assumed... */
  	err = 0;
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  
  	lock_sock(sk);
  
  	if (!vsock_addr_bound(&vsk->local_addr)) {
  		struct sockaddr_vm local_addr;
  
  		vsock_addr_init(&local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
  		err = __vsock_bind(sk, &local_addr);
  		if (err != 0)
  			goto out;
  
  	}
  
  	/* If the provided message contains an address, use that.  Otherwise
  	 * fall back on the socket's remote handle (if it has been connected).
  	 */
  	if (msg->msg_name &&
  	    vsock_addr_cast(msg->msg_name, msg->msg_namelen,
  			    &remote_addr) == 0) {
  		/* Ensure this address is of the right type and is a valid
  		 * destination.
  		 */
  
  		if (remote_addr->svm_cid == VMADDR_CID_ANY)
  			remote_addr->svm_cid = transport->get_local_cid();
  
  		if (!vsock_addr_bound(remote_addr)) {
  			err = -EINVAL;
  			goto out;
  		}
  	} else if (sock->state == SS_CONNECTED) {
  		remote_addr = &vsk->remote_addr;
  
  		if (remote_addr->svm_cid == VMADDR_CID_ANY)
  			remote_addr->svm_cid = transport->get_local_cid();
  
  		/* XXX Should connect() or this function ensure remote_addr is
  		 * bound?
  		 */
  		if (!vsock_addr_bound(&vsk->remote_addr)) {
  			err = -EINVAL;
  			goto out;
  		}
  	} else {
  		err = -EINVAL;
  		goto out;
  	}
  
  	if (!transport->dgram_allow(remote_addr->svm_cid,
  				    remote_addr->svm_port)) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	err = transport->dgram_enqueue(vsk, remote_addr, msg->msg_iov, len);
  
  out:
  	release_sock(sk);
  	return err;
  }
  
  static int vsock_dgram_connect(struct socket *sock,
  			       struct sockaddr *addr, int addr_len, int flags)
  {
  	int err;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	struct sockaddr_vm *remote_addr;
  
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  
  	err = vsock_addr_cast(addr, addr_len, &remote_addr);
  	if (err == -EAFNOSUPPORT && remote_addr->svm_family == AF_UNSPEC) {
  		lock_sock(sk);
  		vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY,
  				VMADDR_PORT_ANY);
  		sock->state = SS_UNCONNECTED;
  		release_sock(sk);
  		return 0;
  	} else if (err != 0)
  		return -EINVAL;
  
  	lock_sock(sk);
  
  	if (!vsock_addr_bound(&vsk->local_addr)) {
  		struct sockaddr_vm local_addr;
  
  		vsock_addr_init(&local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
  		err = __vsock_bind(sk, &local_addr);
  		if (err != 0)
  			goto out;
  
  	}
  
  	if (!transport->dgram_allow(remote_addr->svm_cid,
  				    remote_addr->svm_port)) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
  	sock->state = SS_CONNECTED;
  
  out:
  	release_sock(sk);
  	return err;
  }
  
  static int vsock_dgram_recvmsg(struct kiocb *kiocb, struct socket *sock,
  			       struct msghdr *msg, size_t len, int flags)
  {
  	return transport->dgram_dequeue(kiocb, vsock_sk(sock->sk), msg, len,
  					flags);
  }
  
  static const struct proto_ops vsock_dgram_ops = {
  	.family = PF_VSOCK,
  	.owner = THIS_MODULE,
  	.release = vsock_release,
  	.bind = vsock_bind,
  	.connect = vsock_dgram_connect,
  	.socketpair = sock_no_socketpair,
  	.accept = sock_no_accept,
  	.getname = vsock_getname,
  	.poll = vsock_poll,
  	.ioctl = sock_no_ioctl,
  	.listen = sock_no_listen,
  	.shutdown = vsock_shutdown,
  	.setsockopt = sock_no_setsockopt,
  	.getsockopt = sock_no_getsockopt,
  	.sendmsg = vsock_dgram_sendmsg,
  	.recvmsg = vsock_dgram_recvmsg,
  	.mmap = sock_no_mmap,
  	.sendpage = sock_no_sendpage,
  };
  
  static void vsock_connect_timeout(struct work_struct *work)
  {
  	struct sock *sk;
  	struct vsock_sock *vsk;
  
  	vsk = container_of(work, struct vsock_sock, dwork.work);
  	sk = sk_vsock(vsk);
  
  	lock_sock(sk);
  	if (sk->sk_state == SS_CONNECTING &&
  	    (sk->sk_shutdown != SHUTDOWN_MASK)) {
  		sk->sk_state = SS_UNCONNECTED;
  		sk->sk_err = ETIMEDOUT;
  		sk->sk_error_report(sk);
  	}
  	release_sock(sk);
  
  	sock_put(sk);
  }
  
  static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
  				int addr_len, int flags)
  {
  	int err;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	struct sockaddr_vm *remote_addr;
  	long timeout;
  	DEFINE_WAIT(wait);
  
  	err = 0;
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  
  	lock_sock(sk);
  
  	/* XXX AF_UNSPEC should make us disconnect like AF_INET. */
  	switch (sock->state) {
  	case SS_CONNECTED:
  		err = -EISCONN;
  		goto out;
  	case SS_DISCONNECTING:
  		err = -EINVAL;
  		goto out;
  	case SS_CONNECTING:
  		/* This continues on so we can move sock into the SS_CONNECTED
  		 * state once the connection has completed (at which point err
  		 * will be set to zero also).  Otherwise, we will either wait
  		 * for the connection or return -EALREADY should this be a
  		 * non-blocking call.
  		 */
  		err = -EALREADY;
  		break;
  	default:
  		if ((sk->sk_state == SS_LISTEN) ||
  		    vsock_addr_cast(addr, addr_len, &remote_addr) != 0) {
  			err = -EINVAL;
  			goto out;
  		}
  
  		/* The hypervisor and well-known contexts do not have socket
  		 * endpoints.
  		 */
  		if (!transport->stream_allow(remote_addr->svm_cid,
  					     remote_addr->svm_port)) {
  			err = -ENETUNREACH;
  			goto out;
  		}
  
  		/* Set the remote address that we are connecting to. */
  		memcpy(&vsk->remote_addr, remote_addr,
  		       sizeof(vsk->remote_addr));
  
  		/* Autobind this socket to the local address if necessary. */
  		if (!vsock_addr_bound(&vsk->local_addr)) {
  			struct sockaddr_vm local_addr;
  
  			vsock_addr_init(&local_addr, VMADDR_CID_ANY,
  					VMADDR_PORT_ANY);
  			err = __vsock_bind(sk, &local_addr);
  			if (err != 0)
  				goto out;
  
  		}
  
  		sk->sk_state = SS_CONNECTING;
  
  		err = transport->connect(vsk);
  		if (err < 0)
  			goto out;
  
  		/* Mark sock as connecting and set the error code to in
  		 * progress in case this is a non-blocking connect.
  		 */
  		sock->state = SS_CONNECTING;
  		err = -EINPROGRESS;
  	}
  
  	/* The receive path will handle all communication until we are able to
  	 * enter the connected state.  Here we wait for the connection to be
  	 * completed or a notification of an error.
  	 */
  	timeout = vsk->connect_timeout;
  	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  
  	while (sk->sk_state != SS_CONNECTED && sk->sk_err == 0) {
  		if (flags & O_NONBLOCK) {
  			/* If we're not going to block, we schedule a timeout
  			 * function to generate a timeout on the connection
  			 * attempt, in case the peer doesn't respond in a
  			 * timely manner. We hold on to the socket until the
  			 * timeout fires.
  			 */
  			sock_hold(sk);
  			INIT_DELAYED_WORK(&vsk->dwork,
  					  vsock_connect_timeout);
  			schedule_delayed_work(&vsk->dwork, timeout);
  
  			/* Skip ahead to preserve error code set above. */
  			goto out_wait;
  		}
  
  		release_sock(sk);
  		timeout = schedule_timeout(timeout);
  		lock_sock(sk);
  
  		if (signal_pending(current)) {
  			err = sock_intr_errno(timeout);
  			goto out_wait_error;
  		} else if (timeout == 0) {
  			err = -ETIMEDOUT;
  			goto out_wait_error;
  		}
  
  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  	}
  
  	if (sk->sk_err) {
  		err = -sk->sk_err;
  		goto out_wait_error;
  	} else
  		err = 0;
  
  out_wait:
  	finish_wait(sk_sleep(sk), &wait);
  out:
  	release_sock(sk);
  	return err;
  
  out_wait_error:
  	sk->sk_state = SS_UNCONNECTED;
  	sock->state = SS_UNCONNECTED;
  	goto out_wait;
  }
  
  static int vsock_accept(struct socket *sock, struct socket *newsock, int flags)
  {
  	struct sock *listener;
  	int err;
  	struct sock *connected;
  	struct vsock_sock *vconnected;
  	long timeout;
  	DEFINE_WAIT(wait);
  
  	err = 0;
  	listener = sock->sk;
  
  	lock_sock(listener);
  
  	if (sock->type != SOCK_STREAM) {
  		err = -EOPNOTSUPP;
  		goto out;
  	}
  
  	if (listener->sk_state != SS_LISTEN) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	/* Wait for children sockets to appear; these are the new sockets
  	 * created upon connection establishment.
  	 */
  	timeout = sock_sndtimeo(listener, flags & O_NONBLOCK);
  	prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE);
  
  	while ((connected = vsock_dequeue_accept(listener)) == NULL &&
  	       listener->sk_err == 0) {
  		release_sock(listener);
  		timeout = schedule_timeout(timeout);
  		lock_sock(listener);
  
  		if (signal_pending(current)) {
  			err = sock_intr_errno(timeout);
  			goto out_wait;
  		} else if (timeout == 0) {
  			err = -EAGAIN;
  			goto out_wait;
  		}
  
  		prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE);
  	}
  
  	if (listener->sk_err)
  		err = -listener->sk_err;
  
  	if (connected) {
  		listener->sk_ack_backlog--;
  
  		lock_sock(connected);
  		vconnected = vsock_sk(connected);
  
  		/* If the listener socket has received an error, then we should
  		 * reject this socket and return.  Note that we simply mark the
  		 * socket rejected, drop our reference, and let the cleanup
  		 * function handle the cleanup; the fact that we found it in
  		 * the listener's accept queue guarantees that the cleanup
  		 * function hasn't run yet.
  		 */
  		if (err) {
  			vconnected->rejected = true;
  			release_sock(connected);
  			sock_put(connected);
  			goto out_wait;
  		}
  
  		newsock->state = SS_CONNECTED;
  		sock_graft(connected, newsock);
  		release_sock(connected);
  		sock_put(connected);
  	}
  
  out_wait:
  	finish_wait(sk_sleep(listener), &wait);
  out:
  	release_sock(listener);
  	return err;
  }
  
  static int vsock_listen(struct socket *sock, int backlog)
  {
  	int err;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  
  	sk = sock->sk;
  
  	lock_sock(sk);
  
  	if (sock->type != SOCK_STREAM) {
  		err = -EOPNOTSUPP;
  		goto out;
  	}
  
  	if (sock->state != SS_UNCONNECTED) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	vsk = vsock_sk(sk);
  
  	if (!vsock_addr_bound(&vsk->local_addr)) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	sk->sk_max_ack_backlog = backlog;
  	sk->sk_state = SS_LISTEN;
  
  	err = 0;
  
  out:
  	release_sock(sk);
  	return err;
  }
  
  static int vsock_stream_setsockopt(struct socket *sock,
  				   int level,
  				   int optname,
  				   char __user *optval,
  				   unsigned int optlen)
  {
  	int err;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	u64 val;
  
  	if (level != AF_VSOCK)
  		return -ENOPROTOOPT;
  
  #define COPY_IN(_v)                                       \
  	do {						  \
  		if (optlen < sizeof(_v)) {		  \
  			err = -EINVAL;			  \
  			goto exit;			  \
  		}					  \
  		if (copy_from_user(&_v, optval, sizeof(_v)) != 0) {	\
  			err = -EFAULT;					\
  			goto exit;					\
  		}							\
  	} while (0)
  
  	err = 0;
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  
  	lock_sock(sk);
  
  	switch (optname) {
  	case SO_VM_SOCKETS_BUFFER_SIZE:
  		COPY_IN(val);
  		transport->set_buffer_size(vsk, val);
  		break;
  
  	case SO_VM_SOCKETS_BUFFER_MAX_SIZE:
  		COPY_IN(val);
  		transport->set_max_buffer_size(vsk, val);
  		break;
  
  	case SO_VM_SOCKETS_BUFFER_MIN_SIZE:
  		COPY_IN(val);
  		transport->set_min_buffer_size(vsk, val);
  		break;
  
  	case SO_VM_SOCKETS_CONNECT_TIMEOUT: {
  		struct timeval tv;
  		COPY_IN(tv);
  		if (tv.tv_sec >= 0 && tv.tv_usec < USEC_PER_SEC &&
  		    tv.tv_sec < (MAX_SCHEDULE_TIMEOUT / HZ - 1)) {
  			vsk->connect_timeout = tv.tv_sec * HZ +
  			    DIV_ROUND_UP(tv.tv_usec, (1000000 / HZ));
  			if (vsk->connect_timeout == 0)
  				vsk->connect_timeout =
  				    VSOCK_DEFAULT_CONNECT_TIMEOUT;
  
  		} else {
  			err = -ERANGE;
  		}
  		break;
  	}
  
  	default:
  		err = -ENOPROTOOPT;
  		break;
  	}
  
  #undef COPY_IN
  
  exit:
  	release_sock(sk);
  	return err;
  }
  
  static int vsock_stream_getsockopt(struct socket *sock,
  				   int level, int optname,
  				   char __user *optval,
  				   int __user *optlen)
  {
  	int err;
  	int len;
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	u64 val;
  
  	if (level != AF_VSOCK)
  		return -ENOPROTOOPT;
  
  	err = get_user(len, optlen);
  	if (err != 0)
  		return err;
  
  #define COPY_OUT(_v)                            \
  	do {					\
  		if (len < sizeof(_v))		\
  			return -EINVAL;		\
  						\
  		len = sizeof(_v);		\
  		if (copy_to_user(optval, &_v, len) != 0)	\
  			return -EFAULT;				\
  								\
  	} while (0)
  
  	err = 0;
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  
  	switch (optname) {
  	case SO_VM_SOCKETS_BUFFER_SIZE:
  		val = transport->get_buffer_size(vsk);
  		COPY_OUT(val);
  		break;
  
  	case SO_VM_SOCKETS_BUFFER_MAX_SIZE:
  		val = transport->get_max_buffer_size(vsk);
  		COPY_OUT(val);
  		break;
  
  	case SO_VM_SOCKETS_BUFFER_MIN_SIZE:
  		val = transport->get_min_buffer_size(vsk);
  		COPY_OUT(val);
  		break;
  
  	case SO_VM_SOCKETS_CONNECT_TIMEOUT: {
  		struct timeval tv;
  		tv.tv_sec = vsk->connect_timeout / HZ;
  		tv.tv_usec =
  		    (vsk->connect_timeout -
  		     tv.tv_sec * HZ) * (1000000 / HZ);
  		COPY_OUT(tv);
  		break;
  	}
  	default:
  		return -ENOPROTOOPT;
  	}
  
  	err = put_user(len, optlen);
  	if (err != 0)
  		return -EFAULT;
  
  #undef COPY_OUT
  
  	return 0;
  }
  
  static int vsock_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
  				struct msghdr *msg, size_t len)
  {
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	ssize_t total_written;
  	long timeout;
  	int err;
  	struct vsock_transport_send_notify_data send_data;
  
  	DEFINE_WAIT(wait);
  
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  	total_written = 0;
  	err = 0;
  
  	if (msg->msg_flags & MSG_OOB)
  		return -EOPNOTSUPP;
  
  	lock_sock(sk);
  
  	/* Callers should not provide a destination with stream sockets. */
  	if (msg->msg_namelen) {
  		err = sk->sk_state == SS_CONNECTED ? -EISCONN : -EOPNOTSUPP;
  		goto out;
  	}
  
  	/* Send data only if both sides are not shutdown in the direction. */
  	if (sk->sk_shutdown & SEND_SHUTDOWN ||
  	    vsk->peer_shutdown & RCV_SHUTDOWN) {
  		err = -EPIPE;
  		goto out;
  	}
  
  	if (sk->sk_state != SS_CONNECTED ||
  	    !vsock_addr_bound(&vsk->local_addr)) {
  		err = -ENOTCONN;
  		goto out;
  	}
  
  	if (!vsock_addr_bound(&vsk->remote_addr)) {
  		err = -EDESTADDRREQ;
  		goto out;
  	}
  
  	/* Wait for room in the produce queue to enqueue our user's data. */
  	timeout = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
  
  	err = transport->notify_send_init(vsk, &send_data);
  	if (err < 0)
  		goto out;
  
  	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  
  	while (total_written < len) {
  		ssize_t written;
  
  		while (vsock_stream_has_space(vsk) == 0 &&
  		       sk->sk_err == 0 &&
  		       !(sk->sk_shutdown & SEND_SHUTDOWN) &&
  		       !(vsk->peer_shutdown & RCV_SHUTDOWN)) {
  
  			/* Don't wait for non-blocking sockets. */
  			if (timeout == 0) {
  				err = -EAGAIN;
  				goto out_wait;
  			}
  
  			err = transport->notify_send_pre_block(vsk, &send_data);
  			if (err < 0)
  				goto out_wait;
  
  			release_sock(sk);
  			timeout = schedule_timeout(timeout);
  			lock_sock(sk);
  			if (signal_pending(current)) {
  				err = sock_intr_errno(timeout);
  				goto out_wait;
  			} else if (timeout == 0) {
  				err = -EAGAIN;
  				goto out_wait;
  			}
  
  			prepare_to_wait(sk_sleep(sk), &wait,
  					TASK_INTERRUPTIBLE);
  		}
  
  		/* These checks occur both as part of and after the loop
  		 * conditional since we need to check before and after
  		 * sleeping.
  		 */
  		if (sk->sk_err) {
  			err = -sk->sk_err;
  			goto out_wait;
  		} else if ((sk->sk_shutdown & SEND_SHUTDOWN) ||
  			   (vsk->peer_shutdown & RCV_SHUTDOWN)) {
  			err = -EPIPE;
  			goto out_wait;
  		}
  
  		err = transport->notify_send_pre_enqueue(vsk, &send_data);
  		if (err < 0)
  			goto out_wait;
  
  		/* Note that enqueue will only write as many bytes as are free
  		 * in the produce queue, so we don't need to ensure len is
  		 * smaller than the queue size.  It is the caller's
  		 * responsibility to check how many bytes we were able to send.
  		 */
  
  		written = transport->stream_enqueue(
  				vsk, msg->msg_iov,
  				len - total_written);
  		if (written < 0) {
  			err = -ENOMEM;
  			goto out_wait;
  		}
  
  		total_written += written;
  
  		err = transport->notify_send_post_enqueue(
  				vsk, written, &send_data);
  		if (err < 0)
  			goto out_wait;
  
  	}
  
  out_wait:
  	if (total_written > 0)
  		err = total_written;
  	finish_wait(sk_sleep(sk), &wait);
  out:
  	release_sock(sk);
  	return err;
  }
  
  
  static int
  vsock_stream_recvmsg(struct kiocb *kiocb,
  		     struct socket *sock,
  		     struct msghdr *msg, size_t len, int flags)
  {
  	struct sock *sk;
  	struct vsock_sock *vsk;
  	int err;
  	size_t target;
  	ssize_t copied;
  	long timeout;
  	struct vsock_transport_recv_notify_data recv_data;
  
  	DEFINE_WAIT(wait);
  
  	sk = sock->sk;
  	vsk = vsock_sk(sk);
  	err = 0;
  
  	lock_sock(sk);
  
  	if (sk->sk_state != SS_CONNECTED) {
  		/* Recvmsg is supposed to return 0 if a peer performs an
  		 * orderly shutdown. Differentiate between that case and when a
  		 * peer has not connected or a local shutdown occured with the
  		 * SOCK_DONE flag.
  		 */
  		if (sock_flag(sk, SOCK_DONE))
  			err = 0;
  		else
  			err = -ENOTCONN;
  
  		goto out;
  	}
  
  	if (flags & MSG_OOB) {
  		err = -EOPNOTSUPP;
  		goto out;
  	}
  
  	/* We don't check peer_shutdown flag here since peer may actually shut
  	 * down, but there can be data in the queue that a local socket can
  	 * receive.
  	 */
  	if (sk->sk_shutdown & RCV_SHUTDOWN) {
  		err = 0;
  		goto out;
  	}
  
  	/* It is valid on Linux to pass in a zero-length receive buffer.  This
  	 * is not an error.  We may as well bail out now.
  	 */
  	if (!len) {
  		err = 0;
  		goto out;
  	}
  
  	/* We must not copy less than target bytes into the user's buffer
  	 * before returning successfully, so we wait for the consume queue to
  	 * have that much data to consume before dequeueing.  Note that this
  	 * makes it impossible to handle cases where target is greater than the
  	 * queue size.
  	 */
  	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
  	if (target >= transport->stream_rcvhiwat(vsk)) {
  		err = -ENOMEM;
  		goto out;
  	}
  	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
  	copied = 0;
  
  	err = transport->notify_recv_init(vsk, target, &recv_data);
  	if (err < 0)
  		goto out;
  
  	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  
  	while (1) {
  		s64 ready = vsock_stream_has_data(vsk);
  
  		if (ready < 0) {
  			/* Invalid queue pair content. XXX This should be
  			 * changed to a connection reset in a later change.
  			 */
  
  			err = -ENOMEM;
  			goto out_wait;
  		} else if (ready > 0) {
  			ssize_t read;
  
  			err = transport->notify_recv_pre_dequeue(
  					vsk, target, &recv_data);
  			if (err < 0)
  				break;
  
  			read = transport->stream_dequeue(
  					vsk, msg->msg_iov,
  					len - copied, flags);
  			if (read < 0) {
  				err = -ENOMEM;
  				break;
  			}
  
  			copied += read;
  
  			err = transport->notify_recv_post_dequeue(
  					vsk, target, read,
  					!(flags & MSG_PEEK), &recv_data);
  			if (err < 0)
  				goto out_wait;
  
  			if (read >= target || flags & MSG_PEEK)
  				break;
  
  			target -= read;
  		} else {
  			if (sk->sk_err != 0 || (sk->sk_shutdown & RCV_SHUTDOWN)
  			    || (vsk->peer_shutdown & SEND_SHUTDOWN)) {
  				break;
  			}
  			/* Don't wait for non-blocking sockets. */
  			if (timeout == 0) {
  				err = -EAGAIN;
  				break;
  			}
  
  			err = transport->notify_recv_pre_block(
  					vsk, target, &recv_data);
  			if (err < 0)
  				break;
  
  			release_sock(sk);
  			timeout = schedule_timeout(timeout);
  			lock_sock(sk);
  
  			if (signal_pending(current)) {
  				err = sock_intr_errno(timeout);
  				break;
  			} else if (timeout == 0) {
  				err = -EAGAIN;
  				break;
  			}
  
  			prepare_to_wait(sk_sleep(sk), &wait,
  					TASK_INTERRUPTIBLE);
  		}
  	}
  
  	if (sk->sk_err)
  		err = -sk->sk_err;
  	else if (sk->sk_shutdown & RCV_SHUTDOWN)
  		err = 0;
  
  	if (copied > 0)
  		err = copied;
  
  out_wait:
  	finish_wait(sk_sleep(sk), &wait);
  out:
  	release_sock(sk);
  	return err;
  }
  
  static const struct proto_ops vsock_stream_ops = {
  	.family = PF_VSOCK,
  	.owner = THIS_MODULE,
  	.release = vsock_release,
  	.bind = vsock_bind,
  	.connect = vsock_stream_connect,
  	.socketpair = sock_no_socketpair,
  	.accept = vsock_accept,
  	.getname = vsock_getname,
  	.poll = vsock_poll,
  	.ioctl = sock_no_ioctl,
  	.listen = vsock_listen,
  	.shutdown = vsock_shutdown,
  	.setsockopt = vsock_stream_setsockopt,
  	.getsockopt = vsock_stream_getsockopt,
  	.sendmsg = vsock_stream_sendmsg,
  	.recvmsg = vsock_stream_recvmsg,
  	.mmap = sock_no_mmap,
  	.sendpage = sock_no_sendpage,
  };
  
  static int vsock_create(struct net *net, struct socket *sock,
  			int protocol, int kern)
  {
  	if (!sock)
  		return -EINVAL;
  
  	if (protocol && protocol != PF_VSOCK)
  		return -EPROTONOSUPPORT;
  
  	switch (sock->type) {
  	case SOCK_DGRAM:
  		sock->ops = &vsock_dgram_ops;
  		break;
  	case SOCK_STREAM:
  		sock->ops = &vsock_stream_ops;
  		break;
  	default:
  		return -ESOCKTNOSUPPORT;
  	}
  
  	sock->state = SS_UNCONNECTED;
  
  	return __vsock_create(net, sock, NULL, GFP_KERNEL, 0) ? 0 : -ENOMEM;
  }
  
  static const struct net_proto_family vsock_family_ops = {
  	.family = AF_VSOCK,
  	.create = vsock_create,
  	.owner = THIS_MODULE,
  };
  
  static long vsock_dev_do_ioctl(struct file *filp,
  			       unsigned int cmd, void __user *ptr)
  {
  	u32 __user *p = ptr;
  	int retval = 0;
  
  	switch (cmd) {
  	case IOCTL_VM_SOCKETS_GET_LOCAL_CID:
  		if (put_user(transport->get_local_cid(), p) != 0)
  			retval = -EFAULT;
  		break;
  
  	default:
  		pr_err("Unknown ioctl %d\n", cmd);
  		retval = -EINVAL;
  	}
  
  	return retval;
  }
  
  static long vsock_dev_ioctl(struct file *filp,
  			    unsigned int cmd, unsigned long arg)
  {
  	return vsock_dev_do_ioctl(filp, cmd, (void __user *)arg);
  }
  
  #ifdef CONFIG_COMPAT
  static long vsock_dev_compat_ioctl(struct file *filp,
  				   unsigned int cmd, unsigned long arg)
  {
  	return vsock_dev_do_ioctl(filp, cmd, compat_ptr(arg));
  }
  #endif
  
  static const struct file_operations vsock_device_ops = {
  	.owner		= THIS_MODULE,
  	.unlocked_ioctl	= vsock_dev_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= vsock_dev_compat_ioctl,
  #endif
  	.open		= nonseekable_open,
  };
  
  static struct miscdevice vsock_device = {
  	.name		= "vsock",
  	.fops		= &vsock_device_ops,
  };
  
  static int __vsock_core_init(void)
  {
  	int err;
  
  	vsock_init_tables();
  
  	vsock_device.minor = MISC_DYNAMIC_MINOR;
  	err = misc_register(&vsock_device);
  	if (err) {
  		pr_err("Failed to register misc device\n");
  		return -ENOENT;
  	}
  
  	err = proto_register(&vsock_proto, 1);	/* we want our slab */
  	if (err) {
  		pr_err("Cannot register vsock protocol\n");
  		goto err_misc_deregister;
  	}
  
  	err = sock_register(&vsock_family_ops);
  	if (err) {
  		pr_err("could not register af_vsock (%d) address family: %d\n",
  		       AF_VSOCK, err);
  		goto err_unregister_proto;
  	}
  
  	return 0;
  
  err_unregister_proto:
  	proto_unregister(&vsock_proto);
  err_misc_deregister:
  	misc_deregister(&vsock_device);
  	return err;
  }
  
  int vsock_core_init(const struct vsock_transport *t)
  {
  	int retval = mutex_lock_interruptible(&vsock_register_mutex);
  	if (retval)
  		return retval;
  
  	if (transport) {
  		retval = -EBUSY;
  		goto out;
  	}
  
  	transport = t;
  	retval = __vsock_core_init();
  	if (retval)
  		transport = NULL;
  
  out:
  	mutex_unlock(&vsock_register_mutex);
  	return retval;
  }
  EXPORT_SYMBOL_GPL(vsock_core_init);
  
  void vsock_core_exit(void)
  {
  	mutex_lock(&vsock_register_mutex);
  
  	misc_deregister(&vsock_device);
  	sock_unregister(AF_VSOCK);
  	proto_unregister(&vsock_proto);
  
  	/* We do not want the assignment below re-ordered. */
  	mb();
  	transport = NULL;
  
  	mutex_unlock(&vsock_register_mutex);
  }
  EXPORT_SYMBOL_GPL(vsock_core_exit);
  
  MODULE_AUTHOR("VMware, Inc.");
  MODULE_DESCRIPTION("VMware Virtual Socket Family");
  MODULE_VERSION("1.0.0.0-k");
  MODULE_LICENSE("GPL v2");
  