/*
   * 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.
   */
  
  #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 <net/af_vsock.h>
  
  #include "vmci_transport_notify.h"
  
  static int vmci_transport_recv_dgram_cb(void *data, struct vmci_datagram *dg);
  static int vmci_transport_recv_stream_cb(void *data, struct vmci_datagram *dg);
  static void vmci_transport_peer_detach_cb(u32 sub_id,
  					  const struct vmci_event_data *ed,
  					  void *client_data);
  static void vmci_transport_recv_pkt_work(struct work_struct *work);
  static void vmci_transport_cleanup(struct work_struct *work);
  static int vmci_transport_recv_listen(struct sock *sk,
  				      struct vmci_transport_packet *pkt);
  static int vmci_transport_recv_connecting_server(
  					struct sock *sk,
  					struct sock *pending,
  					struct vmci_transport_packet *pkt);
  static int vmci_transport_recv_connecting_client(
  					struct sock *sk,
  					struct vmci_transport_packet *pkt);
  static int vmci_transport_recv_connecting_client_negotiate(
  					struct sock *sk,
  					struct vmci_transport_packet *pkt);
  static int vmci_transport_recv_connecting_client_invalid(
  					struct sock *sk,
  					struct vmci_transport_packet *pkt);
  static int vmci_transport_recv_connected(struct sock *sk,
  					 struct vmci_transport_packet *pkt);
  static bool vmci_transport_old_proto_override(bool *old_pkt_proto);
  static u16 vmci_transport_new_proto_supported_versions(void);
  static bool vmci_transport_proto_to_notify_struct(struct sock *sk, u16 *proto,
  						  bool old_pkt_proto);
  
  struct vmci_transport_recv_pkt_info {
  	struct work_struct work;
  	struct sock *sk;
  	struct vmci_transport_packet pkt;
  };
  
  static LIST_HEAD(vmci_transport_cleanup_list);
  static DEFINE_SPINLOCK(vmci_transport_cleanup_lock);
  static DECLARE_WORK(vmci_transport_cleanup_work, vmci_transport_cleanup);
  
  static struct vmci_handle vmci_transport_stream_handle = { VMCI_INVALID_ID,
  							   VMCI_INVALID_ID };
  static u32 vmci_transport_qp_resumed_sub_id = VMCI_INVALID_ID;
  
  static int PROTOCOL_OVERRIDE = -1;
  
  #define VMCI_TRANSPORT_DEFAULT_QP_SIZE_MIN   128
  #define VMCI_TRANSPORT_DEFAULT_QP_SIZE       262144
  #define VMCI_TRANSPORT_DEFAULT_QP_SIZE_MAX   262144
  
  /* 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)
  
  /* Helper function to convert from a VMCI error code to a VSock error code. */
  
  static s32 vmci_transport_error_to_vsock_error(s32 vmci_error)
  {
  	int err;
  
  	switch (vmci_error) {
  	case VMCI_ERROR_NO_MEM:
  		err = ENOMEM;
  		break;
  	case VMCI_ERROR_DUPLICATE_ENTRY:
  	case VMCI_ERROR_ALREADY_EXISTS:
  		err = EADDRINUSE;
  		break;
  	case VMCI_ERROR_NO_ACCESS:
  		err = EPERM;
  		break;
  	case VMCI_ERROR_NO_RESOURCES:
  		err = ENOBUFS;
  		break;
  	case VMCI_ERROR_INVALID_RESOURCE:
  		err = EHOSTUNREACH;
  		break;
  	case VMCI_ERROR_INVALID_ARGS:
  	default:
  		err = EINVAL;
  	}
  
  	return err > 0 ? -err : err;
  }
  
  static u32 vmci_transport_peer_rid(u32 peer_cid)
  {
  	if (VMADDR_CID_HYPERVISOR == peer_cid)
  		return VMCI_TRANSPORT_HYPERVISOR_PACKET_RID;
  
  	return VMCI_TRANSPORT_PACKET_RID;
  }
  
  static inline void
  vmci_transport_packet_init(struct vmci_transport_packet *pkt,
  			   struct sockaddr_vm *src,
  			   struct sockaddr_vm *dst,
  			   u8 type,
  			   u64 size,
  			   u64 mode,
  			   struct vmci_transport_waiting_info *wait,
  			   u16 proto,
  			   struct vmci_handle handle)
  {
  	/* We register the stream control handler as an any cid handle so we
  	 * must always send from a source address of VMADDR_CID_ANY
  	 */
  	pkt->dg.src = vmci_make_handle(VMADDR_CID_ANY,
  				       VMCI_TRANSPORT_PACKET_RID);
  	pkt->dg.dst = vmci_make_handle(dst->svm_cid,
  				       vmci_transport_peer_rid(dst->svm_cid));
  	pkt->dg.payload_size = sizeof(*pkt) - sizeof(pkt->dg);
  	pkt->version = VMCI_TRANSPORT_PACKET_VERSION;
  	pkt->type = type;
  	pkt->src_port = src->svm_port;
  	pkt->dst_port = dst->svm_port;
  	memset(&pkt->proto, 0, sizeof(pkt->proto));
  	memset(&pkt->_reserved2, 0, sizeof(pkt->_reserved2));
  
  	switch (pkt->type) {
  	case VMCI_TRANSPORT_PACKET_TYPE_INVALID:
  		pkt->u.size = 0;
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_REQUEST:
  	case VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE:
  		pkt->u.size = size;
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_OFFER:
  	case VMCI_TRANSPORT_PACKET_TYPE_ATTACH:
  		pkt->u.handle = handle;
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_WROTE:
  	case VMCI_TRANSPORT_PACKET_TYPE_READ:
  	case VMCI_TRANSPORT_PACKET_TYPE_RST:
  		pkt->u.size = 0;
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_SHUTDOWN:
  		pkt->u.mode = mode;
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_WAITING_READ:
  	case VMCI_TRANSPORT_PACKET_TYPE_WAITING_WRITE:
  		memcpy(&pkt->u.wait, wait, sizeof(pkt->u.wait));
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_REQUEST2:
  	case VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE2:
  		pkt->u.size = size;
  		pkt->proto = proto;
  		break;
  	}
  }
  
  static inline void
  vmci_transport_packet_get_addresses(struct vmci_transport_packet *pkt,
  				    struct sockaddr_vm *local,
  				    struct sockaddr_vm *remote)
  {
  	vsock_addr_init(local, pkt->dg.dst.context, pkt->dst_port);
  	vsock_addr_init(remote, pkt->dg.src.context, pkt->src_port);
  }
  
  static int
  __vmci_transport_send_control_pkt(struct vmci_transport_packet *pkt,
  				  struct sockaddr_vm *src,
  				  struct sockaddr_vm *dst,
  				  enum vmci_transport_packet_type type,
  				  u64 size,
  				  u64 mode,
  				  struct vmci_transport_waiting_info *wait,
  				  u16 proto,
  				  struct vmci_handle handle,
  				  bool convert_error)
  {
  	int err;
  
  	vmci_transport_packet_init(pkt, src, dst, type, size, mode, wait,
  				   proto, handle);
  	err = vmci_datagram_send(&pkt->dg);
  	if (convert_error && (err < 0))
  		return vmci_transport_error_to_vsock_error(err);
  
  	return err;
  }
  
  static int
  vmci_transport_reply_control_pkt_fast(struct vmci_transport_packet *pkt,
  				      enum vmci_transport_packet_type type,
  				      u64 size,
  				      u64 mode,
  				      struct vmci_transport_waiting_info *wait,
  				      struct vmci_handle handle)
  {
  	struct vmci_transport_packet reply;
  	struct sockaddr_vm src, dst;
  
  	if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST) {
  		return 0;
  	} else {
  		vmci_transport_packet_get_addresses(pkt, &src, &dst);
  		return __vmci_transport_send_control_pkt(&reply, &src, &dst,
  							 type,
  							 size, mode, wait,
  							 VSOCK_PROTO_INVALID,
  							 handle, true);
  	}
  }
  
  static int
  vmci_transport_send_control_pkt_bh(struct sockaddr_vm *src,
  				   struct sockaddr_vm *dst,
  				   enum vmci_transport_packet_type type,
  				   u64 size,
  				   u64 mode,
  				   struct vmci_transport_waiting_info *wait,
  				   struct vmci_handle handle)
  {
  	/* Note that it is safe to use a single packet across all CPUs since
  	 * two tasklets of the same type are guaranteed to not ever run
  	 * simultaneously. If that ever changes, or VMCI stops using tasklets,
  	 * we can use per-cpu packets.
  	 */
  	static struct vmci_transport_packet pkt;
  
  	return __vmci_transport_send_control_pkt(&pkt, src, dst, type,
  						 size, mode, wait,
  						 VSOCK_PROTO_INVALID, handle,
  						 false);
  }
  
  static int
  vmci_transport_send_control_pkt(struct sock *sk,
  				enum vmci_transport_packet_type type,
  				u64 size,
  				u64 mode,
  				struct vmci_transport_waiting_info *wait,
  				u16 proto,
  				struct vmci_handle handle)
  {
  	struct vmci_transport_packet *pkt;
  	struct vsock_sock *vsk;
  	int err;
  
  	vsk = vsock_sk(sk);
  
  	if (!vsock_addr_bound(&vsk->local_addr))
  		return -EINVAL;
  
  	if (!vsock_addr_bound(&vsk->remote_addr))
  		return -EINVAL;
  
  	pkt = kmalloc(sizeof(*pkt), GFP_KERNEL);
  	if (!pkt)
  		return -ENOMEM;
  
  	err = __vmci_transport_send_control_pkt(pkt, &vsk->local_addr,
  						&vsk->remote_addr, type, size,
  						mode, wait, proto, handle,
  						true);
  	kfree(pkt);
  
  	return err;
  }
  
  static int vmci_transport_send_reset_bh(struct sockaddr_vm *dst,
  					struct sockaddr_vm *src,
  					struct vmci_transport_packet *pkt)
  {
  	if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST)
  		return 0;
  	return vmci_transport_send_control_pkt_bh(
  					dst, src,
  					VMCI_TRANSPORT_PACKET_TYPE_RST, 0,
  					0, NULL, VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_reset(struct sock *sk,
  				     struct vmci_transport_packet *pkt)
  {
  	if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST)
  		return 0;
  	return vmci_transport_send_control_pkt(sk,
  					VMCI_TRANSPORT_PACKET_TYPE_RST,
  					0, 0, NULL, VSOCK_PROTO_INVALID,
  					VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_negotiate(struct sock *sk, size_t size)
  {
  	return vmci_transport_send_control_pkt(
  					sk,
  					VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE,
  					size, 0, NULL,
  					VSOCK_PROTO_INVALID,
  					VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_negotiate2(struct sock *sk, size_t size,
  					  u16 version)
  {
  	return vmci_transport_send_control_pkt(
  					sk,
  					VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE2,
  					size, 0, NULL, version,
  					VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_qp_offer(struct sock *sk,
  					struct vmci_handle handle)
  {
  	return vmci_transport_send_control_pkt(
  					sk, VMCI_TRANSPORT_PACKET_TYPE_OFFER, 0,
  					0, NULL,
  					VSOCK_PROTO_INVALID, handle);
  }
  
  static int vmci_transport_send_attach(struct sock *sk,
  				      struct vmci_handle handle)
  {
  	return vmci_transport_send_control_pkt(
  					sk, VMCI_TRANSPORT_PACKET_TYPE_ATTACH,
  					0, 0, NULL, VSOCK_PROTO_INVALID,
  					handle);
  }
  
  static int vmci_transport_reply_reset(struct vmci_transport_packet *pkt)
  {
  	return vmci_transport_reply_control_pkt_fast(
  						pkt,
  						VMCI_TRANSPORT_PACKET_TYPE_RST,
  						0, 0, NULL,
  						VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_invalid_bh(struct sockaddr_vm *dst,
  					  struct sockaddr_vm *src)
  {
  	return vmci_transport_send_control_pkt_bh(
  					dst, src,
  					VMCI_TRANSPORT_PACKET_TYPE_INVALID,
  					0, 0, NULL, VMCI_INVALID_HANDLE);
  }
  
  int vmci_transport_send_wrote_bh(struct sockaddr_vm *dst,
  				 struct sockaddr_vm *src)
  {
  	return vmci_transport_send_control_pkt_bh(
  					dst, src,
  					VMCI_TRANSPORT_PACKET_TYPE_WROTE, 0,
  					0, NULL, VMCI_INVALID_HANDLE);
  }
  
  int vmci_transport_send_read_bh(struct sockaddr_vm *dst,
  				struct sockaddr_vm *src)
  {
  	return vmci_transport_send_control_pkt_bh(
  					dst, src,
  					VMCI_TRANSPORT_PACKET_TYPE_READ, 0,
  					0, NULL, VMCI_INVALID_HANDLE);
  }
  
  int vmci_transport_send_wrote(struct sock *sk)
  {
  	return vmci_transport_send_control_pkt(
  					sk, VMCI_TRANSPORT_PACKET_TYPE_WROTE, 0,
  					0, NULL, VSOCK_PROTO_INVALID,
  					VMCI_INVALID_HANDLE);
  }
  
  int vmci_transport_send_read(struct sock *sk)
  {
  	return vmci_transport_send_control_pkt(
  					sk, VMCI_TRANSPORT_PACKET_TYPE_READ, 0,
  					0, NULL, VSOCK_PROTO_INVALID,
  					VMCI_INVALID_HANDLE);
  }
  
  int vmci_transport_send_waiting_write(struct sock *sk,
  				      struct vmci_transport_waiting_info *wait)
  {
  	return vmci_transport_send_control_pkt(
  				sk, VMCI_TRANSPORT_PACKET_TYPE_WAITING_WRITE,
  				0, 0, wait, VSOCK_PROTO_INVALID,
  				VMCI_INVALID_HANDLE);
  }
  
  int vmci_transport_send_waiting_read(struct sock *sk,
  				     struct vmci_transport_waiting_info *wait)
  {
  	return vmci_transport_send_control_pkt(
  				sk, VMCI_TRANSPORT_PACKET_TYPE_WAITING_READ,
  				0, 0, wait, VSOCK_PROTO_INVALID,
  				VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_shutdown(struct vsock_sock *vsk, int mode)
  {
  	return vmci_transport_send_control_pkt(
  					&vsk->sk,
  					VMCI_TRANSPORT_PACKET_TYPE_SHUTDOWN,
  					0, mode, NULL,
  					VSOCK_PROTO_INVALID,
  					VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_conn_request(struct sock *sk, size_t size)
  {
  	return vmci_transport_send_control_pkt(sk,
  					VMCI_TRANSPORT_PACKET_TYPE_REQUEST,
  					size, 0, NULL,
  					VSOCK_PROTO_INVALID,
  					VMCI_INVALID_HANDLE);
  }
  
  static int vmci_transport_send_conn_request2(struct sock *sk, size_t size,
  					     u16 version)
  {
  	return vmci_transport_send_control_pkt(
  					sk, VMCI_TRANSPORT_PACKET_TYPE_REQUEST2,
  					size, 0, NULL, version,
  					VMCI_INVALID_HANDLE);
  }
  
  static struct sock *vmci_transport_get_pending(
  					struct sock *listener,
  					struct vmci_transport_packet *pkt)
  {
  	struct vsock_sock *vlistener;
  	struct vsock_sock *vpending;
  	struct sock *pending;
  	struct sockaddr_vm src;
  
  	vsock_addr_init(&src, pkt->dg.src.context, pkt->src_port);
  
  	vlistener = vsock_sk(listener);
  
  	list_for_each_entry(vpending, &vlistener->pending_links,
  			    pending_links) {
  		if (vsock_addr_equals_addr(&src, &vpending->remote_addr) &&
  		    pkt->dst_port == vpending->local_addr.svm_port) {
  			pending = sk_vsock(vpending);
  			sock_hold(pending);
  			goto found;
  		}
  	}
  
  	pending = NULL;
  found:
  	return pending;
  
  }
  
  static void vmci_transport_release_pending(struct sock *pending)
  {
  	sock_put(pending);
  }
  
  /* We allow two kinds of sockets to communicate with a restricted VM: 1)
   * trusted sockets 2) sockets from applications running as the same user as the
   * VM (this is only true for the host side and only when using hosted products)
   */
  
  static bool vmci_transport_is_trusted(struct vsock_sock *vsock, u32 peer_cid)
  {
  	return vsock->trusted ||
  	       vmci_is_context_owner(peer_cid, vsock->owner->uid);
  }
  
  /* We allow sending datagrams to and receiving datagrams from a restricted VM
   * only if it is trusted as described in vmci_transport_is_trusted.
   */
  
  static bool vmci_transport_allow_dgram(struct vsock_sock *vsock, u32 peer_cid)
  {
  	if (VMADDR_CID_HYPERVISOR == peer_cid)
  		return true;
  
  	if (vsock->cached_peer != peer_cid) {
  		vsock->cached_peer = peer_cid;
  		if (!vmci_transport_is_trusted(vsock, peer_cid) &&
  		    (vmci_context_get_priv_flags(peer_cid) &
  		     VMCI_PRIVILEGE_FLAG_RESTRICTED)) {
  			vsock->cached_peer_allow_dgram = false;
  		} else {
  			vsock->cached_peer_allow_dgram = true;
  		}
  	}
  
  	return vsock->cached_peer_allow_dgram;
  }
  
  static int
  vmci_transport_queue_pair_alloc(struct vmci_qp **qpair,
  				struct vmci_handle *handle,
  				u64 produce_size,
  				u64 consume_size,
  				u32 peer, u32 flags, bool trusted)
  {
  	int err = 0;
  
  	if (trusted) {
  		/* Try to allocate our queue pair as trusted. This will only
  		 * work if vsock is running in the host.
  		 */
  
  		err = vmci_qpair_alloc(qpair, handle, produce_size,
  				       consume_size,
  				       peer, flags,
  				       VMCI_PRIVILEGE_FLAG_TRUSTED);
  		if (err != VMCI_ERROR_NO_ACCESS)
  			goto out;
  
  	}
  
  	err = vmci_qpair_alloc(qpair, handle, produce_size, consume_size,
  			       peer, flags, VMCI_NO_PRIVILEGE_FLAGS);
  out:
  	if (err < 0) {
  		pr_err("Could not attach to queue pair with %d
  ",
  		       err);
  		err = vmci_transport_error_to_vsock_error(err);
  	}
  
  	return err;
  }
  
  static int
  vmci_transport_datagram_create_hnd(u32 resource_id,
  				   u32 flags,
  				   vmci_datagram_recv_cb recv_cb,
  				   void *client_data,
  				   struct vmci_handle *out_handle)
  {
  	int err = 0;
  
  	/* Try to allocate our datagram handler as trusted. This will only work
  	 * if vsock is running in the host.
  	 */
  
  	err = vmci_datagram_create_handle_priv(resource_id, flags,
  					       VMCI_PRIVILEGE_FLAG_TRUSTED,
  					       recv_cb,
  					       client_data, out_handle);
  
  	if (err == VMCI_ERROR_NO_ACCESS)
  		err = vmci_datagram_create_handle(resource_id, flags,
  						  recv_cb, client_data,
  						  out_handle);
  
  	return err;
  }
  
  /* This is invoked as part of a tasklet that's scheduled when the VMCI
   * interrupt fires.  This is run in bottom-half context and if it ever needs to
   * sleep it should defer that work to a work queue.
   */
  
  static int vmci_transport_recv_dgram_cb(void *data, struct vmci_datagram *dg)
  {
  	struct sock *sk;
  	size_t size;
  	struct sk_buff *skb;
  	struct vsock_sock *vsk;
  
  	sk = (struct sock *)data;
  
  	/* This handler is privileged when this module is running on the host.
  	 * We will get datagrams from all endpoints (even VMs that are in a
  	 * restricted context). If we get one from a restricted context then
  	 * the destination socket must be trusted.
  	 *
  	 * NOTE: We access the socket struct without holding the lock here.
  	 * This is ok because the field we are interested is never modified
  	 * outside of the create and destruct socket functions.
  	 */
  	vsk = vsock_sk(sk);
  	if (!vmci_transport_allow_dgram(vsk, dg->src.context))
  		return VMCI_ERROR_NO_ACCESS;
  
  	size = VMCI_DG_SIZE(dg);
  
  	/* Attach the packet to the socket's receive queue as an sk_buff. */
  	skb = alloc_skb(size, GFP_ATOMIC);
  	if (!skb)
  		return VMCI_ERROR_NO_MEM;
  
  	/* sk_receive_skb() will do a sock_put(), so hold here. */
  	sock_hold(sk);
  	skb_put(skb, size);
  	memcpy(skb->data, dg, size);
  	sk_receive_skb(sk, skb, 0);
  
  	return VMCI_SUCCESS;
  }
  
  static bool vmci_transport_stream_allow(u32 cid, u32 port)
  {
  	static const u32 non_socket_contexts[] = {
  		VMADDR_CID_RESERVED,
  	};
  	int i;
  
  	BUILD_BUG_ON(sizeof(cid) != sizeof(*non_socket_contexts));
  
  	for (i = 0; i < ARRAY_SIZE(non_socket_contexts); i++) {
  		if (cid == non_socket_contexts[i])
  			return false;
  	}
  
  	return true;
  }
  
  /* This is invoked as part of a tasklet that's scheduled when the VMCI
   * interrupt fires.  This is run in bottom-half context but it defers most of
   * its work to the packet handling work queue.
   */
  
  static int vmci_transport_recv_stream_cb(void *data, struct vmci_datagram *dg)
  {
  	struct sock *sk;
  	struct sockaddr_vm dst;
  	struct sockaddr_vm src;
  	struct vmci_transport_packet *pkt;
  	struct vsock_sock *vsk;
  	bool bh_process_pkt;
  	int err;
  
  	sk = NULL;
  	err = VMCI_SUCCESS;
  	bh_process_pkt = false;
  
  	/* Ignore incoming packets from contexts without sockets, or resources
  	 * that aren't vsock implementations.
  	 */
  
  	if (!vmci_transport_stream_allow(dg->src.context, -1)
  	    || vmci_transport_peer_rid(dg->src.context) != dg->src.resource)
  		return VMCI_ERROR_NO_ACCESS;
  
  	if (VMCI_DG_SIZE(dg) < sizeof(*pkt))
  		/* Drop datagrams that do not contain full VSock packets. */
  		return VMCI_ERROR_INVALID_ARGS;
  
  	pkt = (struct vmci_transport_packet *)dg;
  
  	/* Find the socket that should handle this packet.  First we look for a
  	 * connected socket and if there is none we look for a socket bound to
  	 * the destintation address.
  	 */
  	vsock_addr_init(&src, pkt->dg.src.context, pkt->src_port);
  	vsock_addr_init(&dst, pkt->dg.dst.context, pkt->dst_port);
  
  	sk = vsock_find_connected_socket(&src, &dst);
  	if (!sk) {
  		sk = vsock_find_bound_socket(&dst);
  		if (!sk) {
  			/* We could not find a socket for this specified
  			 * address.  If this packet is a RST, we just drop it.
  			 * If it is another packet, we send a RST.  Note that
  			 * we do not send a RST reply to RSTs so that we do not
  			 * continually send RSTs between two endpoints.
  			 *
  			 * Note that since this is a reply, dst is src and src
  			 * is dst.
  			 */
  			if (vmci_transport_send_reset_bh(&dst, &src, pkt) < 0)
  				pr_err("unable to send reset
  ");
  
  			err = VMCI_ERROR_NOT_FOUND;
  			goto out;
  		}
  	}
  
  	/* If the received packet type is beyond all types known to this
  	 * implementation, reply with an invalid message.  Hopefully this will
  	 * help when implementing backwards compatibility in the future.
  	 */
  	if (pkt->type >= VMCI_TRANSPORT_PACKET_TYPE_MAX) {
  		vmci_transport_send_invalid_bh(&dst, &src);
  		err = VMCI_ERROR_INVALID_ARGS;
  		goto out;
  	}
  
  	/* This handler is privileged when this module is running on the host.
  	 * We will get datagram connect requests from all endpoints (even VMs
  	 * that are in a restricted context). If we get one from a restricted
  	 * context then the destination socket must be trusted.
  	 *
  	 * NOTE: We access the socket struct without holding the lock here.
  	 * This is ok because the field we are interested is never modified
  	 * outside of the create and destruct socket functions.
  	 */
  	vsk = vsock_sk(sk);
  	if (!vmci_transport_allow_dgram(vsk, pkt->dg.src.context)) {
  		err = VMCI_ERROR_NO_ACCESS;
  		goto out;
  	}
  
  	/* We do most everything in a work queue, but let's fast path the
  	 * notification of reads and writes to help data transfer performance.
  	 * We can only do this if there is no process context code executing
  	 * for this socket since that may change the state.
  	 */
  	bh_lock_sock(sk);
  
  	if (!sock_owned_by_user(sk)) {
  		/* The local context ID may be out of date, update it. */
  		vsk->local_addr.svm_cid = dst.svm_cid;
  
  		if (sk->sk_state == SS_CONNECTED)
  			vmci_trans(vsk)->notify_ops->handle_notify_pkt(
  					sk, pkt, true, &dst, &src,
  					&bh_process_pkt);
  	}
  
  	bh_unlock_sock(sk);
  
  	if (!bh_process_pkt) {
  		struct vmci_transport_recv_pkt_info *recv_pkt_info;
  
  		recv_pkt_info = kmalloc(sizeof(*recv_pkt_info), GFP_ATOMIC);
  		if (!recv_pkt_info) {
  			if (vmci_transport_send_reset_bh(&dst, &src, pkt) < 0)
  				pr_err("unable to send reset
  ");
  
  			err = VMCI_ERROR_NO_MEM;
  			goto out;
  		}
  
  		recv_pkt_info->sk = sk;
  		memcpy(&recv_pkt_info->pkt, pkt, sizeof(recv_pkt_info->pkt));
  		INIT_WORK(&recv_pkt_info->work, vmci_transport_recv_pkt_work);
  
  		schedule_work(&recv_pkt_info->work);
  		/* Clear sk so that the reference count incremented by one of
  		 * the Find functions above is not decremented below.  We need
  		 * that reference count for the packet handler we've scheduled
  		 * to run.
  		 */
  		sk = NULL;
  	}
  
  out:
  	if (sk)
  		sock_put(sk);
  
  	return err;
  }
  
  static void vmci_transport_handle_detach(struct sock *sk)
  {
  	struct vsock_sock *vsk;
  
  	vsk = vsock_sk(sk);
  	if (!vmci_handle_is_invalid(vmci_trans(vsk)->qp_handle)) {
  		sock_set_flag(sk, SOCK_DONE);
  
  		/* On a detach the peer will not be sending or receiving
  		 * anymore.
  		 */
  		vsk->peer_shutdown = SHUTDOWN_MASK;
  
  		/* We should not be sending anymore since the peer won't be
  		 * there to receive, but we can still receive if there is data
  		 * left in our consume queue.
  		 */
  		if (vsock_stream_has_data(vsk) <= 0) {
  			if (sk->sk_state == SS_CONNECTING) {
  				/* The peer may detach from a queue pair while
  				 * we are still in the connecting state, i.e.,
  				 * if the peer VM is killed after attaching to
  				 * a queue pair, but before we complete the
  				 * handshake. In that case, we treat the detach
  				 * event like a reset.
  				 */
  
  				sk->sk_state = SS_UNCONNECTED;
  				sk->sk_err = ECONNRESET;
  				sk->sk_error_report(sk);
  				return;
  			}
  			sk->sk_state = SS_UNCONNECTED;
  		}
  		sk->sk_state_change(sk);
  	}
  }
  
  static void vmci_transport_peer_detach_cb(u32 sub_id,
  					  const struct vmci_event_data *e_data,
  					  void *client_data)
  {
  	struct vmci_transport *trans = client_data;
  	const struct vmci_event_payload_qp *e_payload;
  
  	e_payload = vmci_event_data_const_payload(e_data);
  
  	/* XXX This is lame, we should provide a way to lookup sockets by
  	 * qp_handle.
  	 */
  	if (vmci_handle_is_invalid(e_payload->handle) ||
  	    vmci_handle_is_equal(trans->qp_handle, e_payload->handle))
  		return;
  
  	/* We don't ask for delayed CBs when we subscribe to this event (we
  	 * pass 0 as flags to vmci_event_subscribe()).  VMCI makes no
  	 * guarantees in that case about what context we might be running in,
  	 * so it could be BH or process, blockable or non-blockable.  So we
  	 * need to account for all possible contexts here.
  	 */
  	spin_lock_bh(&trans->lock);
  	if (!trans->sk)
  		goto out;
  
  	/* Apart from here, trans->lock is only grabbed as part of sk destruct,
  	 * where trans->sk isn't locked.
  	 */
  	bh_lock_sock(trans->sk);
  
  	vmci_transport_handle_detach(trans->sk);
  
  	bh_unlock_sock(trans->sk);
   out:
  	spin_unlock_bh(&trans->lock);
  }
  
  static void vmci_transport_qp_resumed_cb(u32 sub_id,
  					 const struct vmci_event_data *e_data,
  					 void *client_data)
  {
  	vsock_for_each_connected_socket(vmci_transport_handle_detach);
  }
  
  static void vmci_transport_recv_pkt_work(struct work_struct *work)
  {
  	struct vmci_transport_recv_pkt_info *recv_pkt_info;
  	struct vmci_transport_packet *pkt;
  	struct sock *sk;
  
  	recv_pkt_info =
  		container_of(work, struct vmci_transport_recv_pkt_info, work);
  	sk = recv_pkt_info->sk;
  	pkt = &recv_pkt_info->pkt;
  
  	lock_sock(sk);
  
  	/* The local context ID may be out of date. */
  	vsock_sk(sk)->local_addr.svm_cid = pkt->dg.dst.context;
  
  	switch (sk->sk_state) {
  	case VSOCK_SS_LISTEN:
  		vmci_transport_recv_listen(sk, pkt);
  		break;
  	case SS_CONNECTING:
  		/* Processing of pending connections for servers goes through
  		 * the listening socket, so see vmci_transport_recv_listen()
  		 * for that path.
  		 */
  		vmci_transport_recv_connecting_client(sk, pkt);
  		break;
  	case SS_CONNECTED:
  		vmci_transport_recv_connected(sk, pkt);
  		break;
  	default:
  		/* Because this function does not run in the same context as
  		 * vmci_transport_recv_stream_cb it is possible that the
  		 * socket has closed. We need to let the other side know or it
  		 * could be sitting in a connect and hang forever. Send a
  		 * reset to prevent that.
  		 */
  		vmci_transport_send_reset(sk, pkt);
  		break;
  	}
  
  	release_sock(sk);
  	kfree(recv_pkt_info);
  	/* Release reference obtained in the stream callback when we fetched
  	 * this socket out of the bound or connected list.
  	 */
  	sock_put(sk);
  }
  
  static int vmci_transport_recv_listen(struct sock *sk,
  				      struct vmci_transport_packet *pkt)
  {
  	struct sock *pending;
  	struct vsock_sock *vpending;
  	int err;
  	u64 qp_size;
  	bool old_request = false;
  	bool old_pkt_proto = false;
  
  	err = 0;
  
  	/* Because we are in the listen state, we could be receiving a packet
  	 * for ourself or any previous connection requests that we received.
  	 * If it's the latter, we try to find a socket in our list of pending
  	 * connections and, if we do, call the appropriate handler for the
  	 * state that that socket is in.  Otherwise we try to service the
  	 * connection request.
  	 */
  	pending = vmci_transport_get_pending(sk, pkt);
  	if (pending) {
  		lock_sock(pending);
  
  		/* The local context ID may be out of date. */
  		vsock_sk(pending)->local_addr.svm_cid = pkt->dg.dst.context;
  
  		switch (pending->sk_state) {
  		case SS_CONNECTING:
  			err = vmci_transport_recv_connecting_server(sk,
  								    pending,
  								    pkt);
  			break;
  		default:
  			vmci_transport_send_reset(pending, pkt);
  			err = -EINVAL;
  		}
  
  		if (err < 0)
  			vsock_remove_pending(sk, pending);
  
  		release_sock(pending);
  		vmci_transport_release_pending(pending);
  
  		return err;
  	}
  
  	/* The listen state only accepts connection requests.  Reply with a
  	 * reset unless we received a reset.
  	 */
  
  	if (!(pkt->type == VMCI_TRANSPORT_PACKET_TYPE_REQUEST ||
  	      pkt->type == VMCI_TRANSPORT_PACKET_TYPE_REQUEST2)) {
  		vmci_transport_reply_reset(pkt);
  		return -EINVAL;
  	}
  
  	if (pkt->u.size == 0) {
  		vmci_transport_reply_reset(pkt);
  		return -EINVAL;
  	}
  
  	/* If this socket can't accommodate this connection request, we send a
  	 * reset.  Otherwise we create and initialize a child socket and reply
  	 * with a connection negotiation.
  	 */
  	if (sk->sk_ack_backlog >= sk->sk_max_ack_backlog) {
  		vmci_transport_reply_reset(pkt);
  		return -ECONNREFUSED;
  	}
  
  	pending = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
  				 sk->sk_type, 0);
  	if (!pending) {
  		vmci_transport_send_reset(sk, pkt);
  		return -ENOMEM;
  	}
  
  	vpending = vsock_sk(pending);
  
  	vsock_addr_init(&vpending->local_addr, pkt->dg.dst.context,
  			pkt->dst_port);
  	vsock_addr_init(&vpending->remote_addr, pkt->dg.src.context,
  			pkt->src_port);
  
  	/* If the proposed size fits within our min/max, accept it. Otherwise
  	 * propose our own size.
  	 */
  	if (pkt->u.size >= vmci_trans(vpending)->queue_pair_min_size &&
  	    pkt->u.size <= vmci_trans(vpending)->queue_pair_max_size) {
  		qp_size = pkt->u.size;
  	} else {
  		qp_size = vmci_trans(vpending)->queue_pair_size;
  	}
  
  	/* Figure out if we are using old or new requests based on the
  	 * overrides pkt types sent by our peer.
  	 */
  	if (vmci_transport_old_proto_override(&old_pkt_proto)) {
  		old_request = old_pkt_proto;
  	} else {
  		if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_REQUEST)
  			old_request = true;
  		else if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_REQUEST2)
  			old_request = false;
  
  	}
  
  	if (old_request) {
  		/* Handle a REQUEST (or override) */
  		u16 version = VSOCK_PROTO_INVALID;
  		if (vmci_transport_proto_to_notify_struct(
  			pending, &version, true))
  			err = vmci_transport_send_negotiate(pending, qp_size);
  		else
  			err = -EINVAL;
  
  	} else {
  		/* Handle a REQUEST2 (or override) */
  		int proto_int = pkt->proto;
  		int pos;
  		u16 active_proto_version = 0;
  
  		/* The list of possible protocols is the intersection of all
  		 * protocols the client supports ... plus all the protocols we
  		 * support.
  		 */
  		proto_int &= vmci_transport_new_proto_supported_versions();
  
  		/* We choose the highest possible protocol version and use that
  		 * one.
  		 */
  		pos = fls(proto_int);
  		if (pos) {
  			active_proto_version = (1 << (pos - 1));
  			if (vmci_transport_proto_to_notify_struct(
  				pending, &active_proto_version, false))
  				err = vmci_transport_send_negotiate2(pending,
  							qp_size,
  							active_proto_version);
  			else
  				err = -EINVAL;
  
  		} else {
  			err = -EINVAL;
  		}
  	}
  
  	if (err < 0) {
  		vmci_transport_send_reset(sk, pkt);
  		sock_put(pending);
  		err = vmci_transport_error_to_vsock_error(err);
  		goto out;
  	}
  
  	vsock_add_pending(sk, pending);
  	sk->sk_ack_backlog++;
  
  	pending->sk_state = SS_CONNECTING;
  	vmci_trans(vpending)->produce_size =
  		vmci_trans(vpending)->consume_size = qp_size;
  	vmci_trans(vpending)->queue_pair_size = qp_size;
  
  	vmci_trans(vpending)->notify_ops->process_request(pending);
  
  	/* We might never receive another message for this socket and it's not
  	 * connected to any process, so we have to ensure it gets cleaned up
  	 * ourself.  Our delayed work function will take care of that.  Note
  	 * that we do not ever cancel this function since we have few
  	 * guarantees about its state when calling cancel_delayed_work().
  	 * Instead we hold a reference on the socket for that function and make
  	 * it capable of handling cases where it needs to do nothing but
  	 * release that reference.
  	 */
  	vpending->listener = sk;
  	sock_hold(sk);
  	sock_hold(pending);
  	INIT_DELAYED_WORK(&vpending->dwork, vsock_pending_work);
  	schedule_delayed_work(&vpending->dwork, HZ);
  
  out:
  	return err;
  }
  
  static int
  vmci_transport_recv_connecting_server(struct sock *listener,
  				      struct sock *pending,
  				      struct vmci_transport_packet *pkt)
  {
  	struct vsock_sock *vpending;
  	struct vmci_handle handle;
  	struct vmci_qp *qpair;
  	bool is_local;
  	u32 flags;
  	u32 detach_sub_id;
  	int err;
  	int skerr;
  
  	vpending = vsock_sk(pending);
  	detach_sub_id = VMCI_INVALID_ID;
  
  	switch (pkt->type) {
  	case VMCI_TRANSPORT_PACKET_TYPE_OFFER:
  		if (vmci_handle_is_invalid(pkt->u.handle)) {
  			vmci_transport_send_reset(pending, pkt);
  			skerr = EPROTO;
  			err = -EINVAL;
  			goto destroy;
  		}
  		break;
  	default:
  		/* Close and cleanup the connection. */
  		vmci_transport_send_reset(pending, pkt);
  		skerr = EPROTO;
  		err = pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL;
  		goto destroy;
  	}
  
  	/* In order to complete the connection we need to attach to the offered
  	 * queue pair and send an attach notification.  We also subscribe to the
  	 * detach event so we know when our peer goes away, and we do that
  	 * before attaching so we don't miss an event.  If all this succeeds,
  	 * we update our state and wakeup anything waiting in accept() for a
  	 * connection.
  	 */
  
  	/* We don't care about attach since we ensure the other side has
  	 * attached by specifying the ATTACH_ONLY flag below.
  	 */
  	err = vmci_event_subscribe(VMCI_EVENT_QP_PEER_DETACH,
  				   vmci_transport_peer_detach_cb,
  				   vmci_trans(vpending), &detach_sub_id);
  	if (err < VMCI_SUCCESS) {
  		vmci_transport_send_reset(pending, pkt);
  		err = vmci_transport_error_to_vsock_error(err);
  		skerr = -err;
  		goto destroy;
  	}
  
  	vmci_trans(vpending)->detach_sub_id = detach_sub_id;
  
  	/* Now attach to the queue pair the client created. */
  	handle = pkt->u.handle;
  
  	/* vpending->local_addr always has a context id so we do not need to
  	 * worry about VMADDR_CID_ANY in this case.
  	 */
  	is_local =
  	    vpending->remote_addr.svm_cid == vpending->local_addr.svm_cid;
  	flags = VMCI_QPFLAG_ATTACH_ONLY;
  	flags |= is_local ? VMCI_QPFLAG_LOCAL : 0;
  
  	err = vmci_transport_queue_pair_alloc(
  					&qpair,
  					&handle,
  					vmci_trans(vpending)->produce_size,
  					vmci_trans(vpending)->consume_size,
  					pkt->dg.src.context,
  					flags,
  					vmci_transport_is_trusted(
  						vpending,
  						vpending->remote_addr.svm_cid));
  	if (err < 0) {
  		vmci_transport_send_reset(pending, pkt);
  		skerr = -err;
  		goto destroy;
  	}
  
  	vmci_trans(vpending)->qp_handle = handle;
  	vmci_trans(vpending)->qpair = qpair;
  
  	/* When we send the attach message, we must be ready to handle incoming
  	 * control messages on the newly connected socket. So we move the
  	 * pending socket to the connected state before sending the attach
  	 * message. Otherwise, an incoming packet triggered by the attach being
  	 * received by the peer may be processed concurrently with what happens
  	 * below after sending the attach message, and that incoming packet
  	 * will find the listening socket instead of the (currently) pending
  	 * socket. Note that enqueueing the socket increments the reference
  	 * count, so even if a reset comes before the connection is accepted,
  	 * the socket will be valid until it is removed from the queue.
  	 *
  	 * If we fail sending the attach below, we remove the socket from the
  	 * connected list and move the socket to SS_UNCONNECTED before
  	 * releasing the lock, so a pending slow path processing of an incoming
  	 * packet will not see the socket in the connected state in that case.
  	 */
  	pending->sk_state = SS_CONNECTED;
  
  	vsock_insert_connected(vpending);
  
  	/* Notify our peer of our attach. */
  	err = vmci_transport_send_attach(pending, handle);
  	if (err < 0) {
  		vsock_remove_connected(vpending);
  		pr_err("Could not send attach
  ");
  		vmci_transport_send_reset(pending, pkt);
  		err = vmci_transport_error_to_vsock_error(err);
  		skerr = -err;
  		goto destroy;
  	}
  
  	/* We have a connection. Move the now connected socket from the
  	 * listener's pending list to the accept queue so callers of accept()
  	 * can find it.
  	 */
  	vsock_remove_pending(listener, pending);
  	vsock_enqueue_accept(listener, pending);
  
  	/* Callers of accept() will be be waiting on the listening socket, not
  	 * the pending socket.
  	 */
  	listener->sk_data_ready(listener);
  
  	return 0;
  
  destroy:
  	pending->sk_err = skerr;
  	pending->sk_state = SS_UNCONNECTED;
  	/* As long as we drop our reference, all necessary cleanup will handle
  	 * when the cleanup function drops its reference and our destruct
  	 * implementation is called.  Note that since the listen handler will
  	 * remove pending from the pending list upon our failure, the cleanup
  	 * function won't drop the additional reference, which is why we do it
  	 * here.
  	 */
  	sock_put(pending);
  
  	return err;
  }
  
  static int
  vmci_transport_recv_connecting_client(struct sock *sk,
  				      struct vmci_transport_packet *pkt)
  {
  	struct vsock_sock *vsk;
  	int err;
  	int skerr;
  
  	vsk = vsock_sk(sk);
  
  	switch (pkt->type) {
  	case VMCI_TRANSPORT_PACKET_TYPE_ATTACH:
  		if (vmci_handle_is_invalid(pkt->u.handle) ||
  		    !vmci_handle_is_equal(pkt->u.handle,
  					  vmci_trans(vsk)->qp_handle)) {
  			skerr = EPROTO;
  			err = -EINVAL;
  			goto destroy;
  		}
  
  		/* Signify the socket is connected and wakeup the waiter in
  		 * connect(). Also place the socket in the connected table for
  		 * accounting (it can already be found since it's in the bound
  		 * table).
  		 */
  		sk->sk_state = SS_CONNECTED;
  		sk->sk_socket->state = SS_CONNECTED;
  		vsock_insert_connected(vsk);
  		sk->sk_state_change(sk);
  
  		break;
  	case VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE:
  	case VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE2:
  		if (pkt->u.size == 0
  		    || pkt->dg.src.context != vsk->remote_addr.svm_cid
  		    || pkt->src_port != vsk->remote_addr.svm_port
  		    || !vmci_handle_is_invalid(vmci_trans(vsk)->qp_handle)
  		    || vmci_trans(vsk)->qpair
  		    || vmci_trans(vsk)->produce_size != 0
  		    || vmci_trans(vsk)->consume_size != 0
  		    || vmci_trans(vsk)->detach_sub_id != VMCI_INVALID_ID) {
  			skerr = EPROTO;
  			err = -EINVAL;
  
  			goto destroy;
  		}
  
  		err = vmci_transport_recv_connecting_client_negotiate(sk, pkt);
  		if (err) {
  			skerr = -err;
  			goto destroy;
  		}
  
  		break;
  	case VMCI_TRANSPORT_PACKET_TYPE_INVALID:
  		err = vmci_transport_recv_connecting_client_invalid(sk, pkt);
  		if (err) {
  			skerr = -err;
  			goto destroy;
  		}
  
  		break;
  	case VMCI_TRANSPORT_PACKET_TYPE_RST:
  		/* Older versions of the linux code (WS 6.5 / ESX 4.0) used to
  		 * continue processing here after they sent an INVALID packet.
  		 * This meant that we got a RST after the INVALID. We ignore a
  		 * RST after an INVALID. The common code doesn't send the RST
  		 * ... so we can hang if an old version of the common code
  		 * fails between getting a REQUEST and sending an OFFER back.
  		 * Not much we can do about it... except hope that it doesn't
  		 * happen.
  		 */
  		if (vsk->ignore_connecting_rst) {
  			vsk->ignore_connecting_rst = false;
  		} else {
  			skerr = ECONNRESET;
  			err = 0;
  			goto destroy;
  		}
  
  		break;
  	default:
  		/* Close and cleanup the connection. */
  		skerr = EPROTO;
  		err = -EINVAL;
  		goto destroy;
  	}
  
  	return 0;
  
  destroy:
  	vmci_transport_send_reset(sk, pkt);
  
  	sk->sk_state = SS_UNCONNECTED;
  	sk->sk_err = skerr;
  	sk->sk_error_report(sk);
  	return err;
  }
  
  static int vmci_transport_recv_connecting_client_negotiate(
  					struct sock *sk,
  					struct vmci_transport_packet *pkt)
  {
  	int err;
  	struct vsock_sock *vsk;
  	struct vmci_handle handle;
  	struct vmci_qp *qpair;
  	u32 detach_sub_id;
  	bool is_local;
  	u32 flags;
  	bool old_proto = true;
  	bool old_pkt_proto;
  	u16 version;
  
  	vsk = vsock_sk(sk);
  	handle = VMCI_INVALID_HANDLE;
  	detach_sub_id = VMCI_INVALID_ID;
  
  	/* If we have gotten here then we should be past the point where old
  	 * linux vsock could have sent the bogus rst.
  	 */
  	vsk->sent_request = false;
  	vsk->ignore_connecting_rst = false;
  
  	/* Verify that we're OK with the proposed queue pair size */
  	if (pkt->u.size < vmci_trans(vsk)->queue_pair_min_size ||
  	    pkt->u.size > vmci_trans(vsk)->queue_pair_max_size) {
  		err = -EINVAL;
  		goto destroy;
  	}
  
  	/* At this point we know the CID the peer is using to talk to us. */
  
  	if (vsk->local_addr.svm_cid == VMADDR_CID_ANY)
  		vsk->local_addr.svm_cid = pkt->dg.dst.context;
  
  	/* Setup the notify ops to be the highest supported version that both
  	 * the server and the client support.
  	 */
  
  	if (vmci_transport_old_proto_override(&old_pkt_proto)) {
  		old_proto = old_pkt_proto;
  	} else {
  		if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE)
  			old_proto = true;
  		else if (pkt->type == VMCI_TRANSPORT_PACKET_TYPE_NEGOTIATE2)
  			old_proto = false;
  
  	}
  
  	if (old_proto)
  		version = VSOCK_PROTO_INVALID;
  	else
  		version = pkt->proto;
  
  	if (!vmci_transport_proto_to_notify_struct(sk, &version, old_proto)) {
  		err = -EINVAL;
  		goto destroy;
  	}
  
  	/* Subscribe to detach events first.
  	 *
  	 * XXX We attach once for each queue pair created for now so it is easy
  	 * to find the socket (it's provided), but later we should only
  	 * subscribe once and add a way to lookup sockets by queue pair handle.
  	 */
  	err = vmci_event_subscribe(VMCI_EVENT_QP_PEER_DETACH,
  				   vmci_transport_peer_detach_cb,
  				   vmci_trans(vsk), &detach_sub_id);
  	if (err < VMCI_SUCCESS) {
  		err = vmci_transport_error_to_vsock_error(err);
  		goto destroy;
  	}
  
  	/* Make VMCI select the handle for us. */
  	handle = VMCI_INVALID_HANDLE;
  	is_local = vsk->remote_addr.svm_cid == vsk->local_addr.svm_cid;
  	flags = is_local ? VMCI_QPFLAG_LOCAL : 0;
  
  	err = vmci_transport_queue_pair_alloc(&qpair,
  					      &handle,
  					      pkt->u.size,
  					      pkt->u.size,
  					      vsk->remote_addr.svm_cid,
  					      flags,
  					      vmci_transport_is_trusted(
  						  vsk,
  						  vsk->
  						  remote_addr.svm_cid));
  	if (err < 0)
  		goto destroy;
  
  	err = vmci_transport_send_qp_offer(sk, handle);
  	if (err < 0) {
  		err = vmci_transport_error_to_vsock_error(err);
  		goto destroy;
  	}
  
  	vmci_trans(vsk)->qp_handle = handle;
  	vmci_trans(vsk)->qpair = qpair;
  
  	vmci_trans(vsk)->produce_size = vmci_trans(vsk)->consume_size =
  		pkt->u.size;
  
  	vmci_trans(vsk)->detach_sub_id = detach_sub_id;
  
  	vmci_trans(vsk)->notify_ops->process_negotiate(sk);
  
  	return 0;
  
  destroy:
  	if (detach_sub_id != VMCI_INVALID_ID)
  		vmci_event_unsubscribe(detach_sub_id);
  
  	if (!vmci_handle_is_invalid(handle))
  		vmci_qpair_detach(&qpair);
  
  	return err;
  }
  
  static int
  vmci_transport_recv_connecting_client_invalid(struct sock *sk,
  					      struct vmci_transport_packet *pkt)
  {
  	int err = 0;
  	struct vsock_sock *vsk = vsock_sk(sk);
  
  	if (vsk->sent_request) {
  		vsk->sent_request = false;
  		vsk->ignore_connecting_rst = true;
  
  		err = vmci_transport_send_conn_request(
  			sk, vmci_trans(vsk)->queue_pair_size);
  		if (err < 0)
  			err = vmci_transport_error_to_vsock_error(err);
  		else
  			err = 0;
  
  	}
  
  	return err;
  }
  
  static int vmci_transport_recv_connected(struct sock *sk,
  					 struct vmci_transport_packet *pkt)
  {
  	struct vsock_sock *vsk;
  	bool pkt_processed = false;
  
  	/* In cases where we are closing the connection, it's sufficient to
  	 * mark the state change (and maybe error) and wake up any waiting
  	 * threads. Since this is a connected socket, it's owned by a user
  	 * process and will be cleaned up when the failure is passed back on
  	 * the current or next system call.  Our system call implementations
  	 * must therefore check for error and state changes on entry and when
  	 * being awoken.
  	 */
  	switch (pkt->type) {
  	case VMCI_TRANSPORT_PACKET_TYPE_SHUTDOWN:
  		if (pkt->u.mode) {
  			vsk = vsock_sk(sk);
  
  			vsk->peer_shutdown |= pkt->u.mode;
  			sk->sk_state_change(sk);
  		}
  		break;
  
  	case VMCI_TRANSPORT_PACKET_TYPE_RST:
  		vsk = vsock_sk(sk);
  		/* It is possible that we sent our peer a message (e.g a
  		 * WAITING_READ) right before we got notified that the peer had
  		 * detached. If that happens then we can get a RST pkt back
  		 * from our peer even though there is data available for us to
  		 * read. In that case, don't shutdown the socket completely but
  		 * instead allow the local client to finish reading data off
  		 * the queuepair. Always treat a RST pkt in connected mode like
  		 * a clean shutdown.
  		 */
  		sock_set_flag(sk, SOCK_DONE);
  		vsk->peer_shutdown = SHUTDOWN_MASK;
  		if (vsock_stream_has_data(vsk) <= 0)
  			sk->sk_state = SS_DISCONNECTING;
  
  		sk->sk_state_change(sk);
  		break;
  
  	default:
  		vsk = vsock_sk(sk);
  		vmci_trans(vsk)->notify_ops->handle_notify_pkt(
  				sk, pkt, false, NULL, NULL,
  				&pkt_processed);
  		if (!pkt_processed)
  			return -EINVAL;
  
  		break;
  	}
  
  	return 0;
  }
  
  static int vmci_transport_socket_init(struct vsock_sock *vsk,
  				      struct vsock_sock *psk)
  {
  	vsk->trans = kmalloc(sizeof(struct vmci_transport), GFP_KERNEL);
  	if (!vsk->trans)
  		return -ENOMEM;
  
  	vmci_trans(vsk)->dg_handle = VMCI_INVALID_HANDLE;
  	vmci_trans(vsk)->qp_handle = VMCI_INVALID_HANDLE;
  	vmci_trans(vsk)->qpair = NULL;
  	vmci_trans(vsk)->produce_size = vmci_trans(vsk)->consume_size = 0;
  	vmci_trans(vsk)->detach_sub_id = VMCI_INVALID_ID;
  	vmci_trans(vsk)->notify_ops = NULL;
  	INIT_LIST_HEAD(&vmci_trans(vsk)->elem);
  	vmci_trans(vsk)->sk = &vsk->sk;
  	spin_lock_init(&vmci_trans(vsk)->lock);
  	if (psk) {
  		vmci_trans(vsk)->queue_pair_size =
  			vmci_trans(psk)->queue_pair_size;
  		vmci_trans(vsk)->queue_pair_min_size =
  			vmci_trans(psk)->queue_pair_min_size;
  		vmci_trans(vsk)->queue_pair_max_size =
  			vmci_trans(psk)->queue_pair_max_size;
  	} else {
  		vmci_trans(vsk)->queue_pair_size =
  			VMCI_TRANSPORT_DEFAULT_QP_SIZE;
  		vmci_trans(vsk)->queue_pair_min_size =
  			 VMCI_TRANSPORT_DEFAULT_QP_SIZE_MIN;
  		vmci_trans(vsk)->queue_pair_max_size =
  			VMCI_TRANSPORT_DEFAULT_QP_SIZE_MAX;
  	}
  
  	return 0;
  }
  
  static void vmci_transport_free_resources(struct list_head *transport_list)
  {
  	while (!list_empty(transport_list)) {
  		struct vmci_transport *transport =
  		    list_first_entry(transport_list, struct vmci_transport,
  				     elem);
  		list_del(&transport->elem);
  
  		if (transport->detach_sub_id != VMCI_INVALID_ID) {
  			vmci_event_unsubscribe(transport->detach_sub_id);
  			transport->detach_sub_id = VMCI_INVALID_ID;
  		}
  
  		if (!vmci_handle_is_invalid(transport->qp_handle)) {
  			vmci_qpair_detach(&transport->qpair);
  			transport->qp_handle = VMCI_INVALID_HANDLE;
  			transport->produce_size = 0;
  			transport->consume_size = 0;
  		}
  
  		kfree(transport);
  	}
  }
  
  static void vmci_transport_cleanup(struct work_struct *work)
  {
  	LIST_HEAD(pending);
  
  	spin_lock_bh(&vmci_transport_cleanup_lock);
  	list_replace_init(&vmci_transport_cleanup_list, &pending);
  	spin_unlock_bh(&vmci_transport_cleanup_lock);
  	vmci_transport_free_resources(&pending);
  }
  
  static void vmci_transport_destruct(struct vsock_sock *vsk)
  {
  	/* Ensure that the detach callback doesn't use the sk/vsk
  	 * we are about to destruct.
  	 */
  	spin_lock_bh(&vmci_trans(vsk)->lock);
  	vmci_trans(vsk)->sk = NULL;
  	spin_unlock_bh(&vmci_trans(vsk)->lock);
  
  	if (vmci_trans(vsk)->notify_ops)
  		vmci_trans(vsk)->notify_ops->socket_destruct(vsk);
  
  	spin_lock_bh(&vmci_transport_cleanup_lock);
  	list_add(&vmci_trans(vsk)->elem, &vmci_transport_cleanup_list);
  	spin_unlock_bh(&vmci_transport_cleanup_lock);
  	schedule_work(&vmci_transport_cleanup_work);
  
  	vsk->trans = NULL;
  }
  
  static void vmci_transport_release(struct vsock_sock *vsk)
  {
  	if (!vmci_handle_is_invalid(vmci_trans(vsk)->dg_handle)) {
  		vmci_datagram_destroy_handle(vmci_trans(vsk)->dg_handle);
  		vmci_trans(vsk)->dg_handle = VMCI_INVALID_HANDLE;
  	}
  }
  
  static int vmci_transport_dgram_bind(struct vsock_sock *vsk,
  				     struct sockaddr_vm *addr)
  {
  	u32 port;
  	u32 flags;
  	int err;
  
  	/* VMCI will select a resource ID for us if we provide
  	 * VMCI_INVALID_ID.
  	 */
  	port = addr->svm_port == VMADDR_PORT_ANY ?
  			VMCI_INVALID_ID : addr->svm_port;
  
  	if (port <= LAST_RESERVED_PORT && !capable(CAP_NET_BIND_SERVICE))
  		return -EACCES;
  
  	flags = addr->svm_cid == VMADDR_CID_ANY ?
  				VMCI_FLAG_ANYCID_DG_HND : 0;
  
  	err = vmci_transport_datagram_create_hnd(port, flags,
  						 vmci_transport_recv_dgram_cb,
  						 &vsk->sk,
  						 &vmci_trans(vsk)->dg_handle);
  	if (err < VMCI_SUCCESS)
  		return vmci_transport_error_to_vsock_error(err);
  	vsock_addr_init(&vsk->local_addr, addr->svm_cid,
  			vmci_trans(vsk)->dg_handle.resource);
  
  	return 0;
  }
  
  static int vmci_transport_dgram_enqueue(
  	struct vsock_sock *vsk,
  	struct sockaddr_vm *remote_addr,
  	struct msghdr *msg,
  	size_t len)
  {
  	int err;
  	struct vmci_datagram *dg;
  
  	if (len > VMCI_MAX_DG_PAYLOAD_SIZE)
  		return -EMSGSIZE;
  
  	if (!vmci_transport_allow_dgram(vsk, remote_addr->svm_cid))
  		return -EPERM;
  
  	/* Allocate a buffer for the user's message and our packet header. */
  	dg = kmalloc(len + sizeof(*dg), GFP_KERNEL);
  	if (!dg)
  		return -ENOMEM;
  
  	memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len);
  
  	dg->dst = vmci_make_handle(remote_addr->svm_cid,
  				   remote_addr->svm_port);
  	dg->src = vmci_make_handle(vsk->local_addr.svm_cid,
  				   vsk->local_addr.svm_port);
  	dg->payload_size = len;
  
  	err = vmci_datagram_send(dg);
  	kfree(dg);
  	if (err < 0)
  		return vmci_transport_error_to_vsock_error(err);
  
  	return err - sizeof(*dg);
  }
  
  static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
  					struct msghdr *msg, size_t len,
  					int flags)
  {
  	int err;
  	int noblock;
  	struct vmci_datagram *dg;
  	size_t payload_len;
  	struct sk_buff *skb;
  
  	noblock = flags & MSG_DONTWAIT;
  
  	if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
  		return -EOPNOTSUPP;
  
  	/* Retrieve the head sk_buff from the socket's receive queue. */
  	err = 0;
  	skb = skb_recv_datagram(&vsk->sk, flags, noblock, &err);
  	if (err)
  		return err;
  
  	if (!skb)
  		return -EAGAIN;
  
  	dg = (struct vmci_datagram *)skb->data;
  	if (!dg)
  		/* err is 0, meaning we read zero bytes. */
  		goto out;
  
  	payload_len = dg->payload_size;
  	/* Ensure the sk_buff matches the payload size claimed in the packet. */
  	if (payload_len != skb->len - sizeof(*dg)) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	if (payload_len > len) {
  		payload_len = len;
  		msg->msg_flags |= MSG_TRUNC;
  	}
  
  	/* Place the datagram payload in the user's iovec. */
  	err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len);
  	if (err)
  		goto out;
  
  	if (msg->msg_name) {
  		/* Provide the address of the sender. */
  		DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
  		vsock_addr_init(vm_addr, dg->src.context, dg->src.resource);
  		msg->msg_namelen = sizeof(*vm_addr);
  	}
  	err = payload_len;
  
  out:
  	skb_free_datagram(&vsk->sk, skb);
  	return err;
  }
  
  static bool vmci_transport_dgram_allow(u32 cid, u32 port)
  {
  	if (cid == VMADDR_CID_HYPERVISOR) {
  		/* Registrations of PBRPC Servers do not modify VMX/Hypervisor
  		 * state and are allowed.
  		 */
  		return port == VMCI_UNITY_PBRPC_REGISTER;
  	}
  
  	return true;
  }
  
  static int vmci_transport_connect(struct vsock_sock *vsk)
  {
  	int err;
  	bool old_pkt_proto = false;
  	struct sock *sk = &vsk->sk;
  
  	if (vmci_transport_old_proto_override(&old_pkt_proto) &&
  		old_pkt_proto) {
  		err = vmci_transport_send_conn_request(
  			sk, vmci_trans(vsk)->queue_pair_size);
  		if (err < 0) {
  			sk->sk_state = SS_UNCONNECTED;
  			return err;
  		}
  	} else {
  		int supported_proto_versions =
  			vmci_transport_new_proto_supported_versions();
  		err = vmci_transport_send_conn_request2(
  				sk, vmci_trans(vsk)->queue_pair_size,
  				supported_proto_versions);
  		if (err < 0) {
  			sk->sk_state = SS_UNCONNECTED;
  			return err;
  		}
  
  		vsk->sent_request = true;
  	}
  
  	return err;
  }
  
  static ssize_t vmci_transport_stream_dequeue(
  	struct vsock_sock *vsk,
  	struct msghdr *msg,
  	size_t len,
  	int flags)
  {
  	if (flags & MSG_PEEK)
  		return vmci_qpair_peekv(vmci_trans(vsk)->qpair, msg, len, 0);
  	else
  		return vmci_qpair_dequev(vmci_trans(vsk)->qpair, msg, len, 0);
  }
  
  static ssize_t vmci_transport_stream_enqueue(
  	struct vsock_sock *vsk,
  	struct msghdr *msg,
  	size_t len)
  {
  	return vmci_qpair_enquev(vmci_trans(vsk)->qpair, msg, len, 0);
  }
  
  static s64 vmci_transport_stream_has_data(struct vsock_sock *vsk)
  {
  	return vmci_qpair_consume_buf_ready(vmci_trans(vsk)->qpair);
  }
  
  static s64 vmci_transport_stream_has_space(struct vsock_sock *vsk)
  {
  	return vmci_qpair_produce_free_space(vmci_trans(vsk)->qpair);
  }
  
  static u64 vmci_transport_stream_rcvhiwat(struct vsock_sock *vsk)
  {
  	return vmci_trans(vsk)->consume_size;
  }
  
  static bool vmci_transport_stream_is_active(struct vsock_sock *vsk)
  {
  	return !vmci_handle_is_invalid(vmci_trans(vsk)->qp_handle);
  }
  
  static u64 vmci_transport_get_buffer_size(struct vsock_sock *vsk)
  {
  	return vmci_trans(vsk)->queue_pair_size;
  }
  
  static u64 vmci_transport_get_min_buffer_size(struct vsock_sock *vsk)
  {
  	return vmci_trans(vsk)->queue_pair_min_size;
  }
  
  static u64 vmci_transport_get_max_buffer_size(struct vsock_sock *vsk)
  {
  	return vmci_trans(vsk)->queue_pair_max_size;
  }
  
  static void vmci_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
  {
  	if (val < vmci_trans(vsk)->queue_pair_min_size)
  		vmci_trans(vsk)->queue_pair_min_size = val;
  	if (val > vmci_trans(vsk)->queue_pair_max_size)
  		vmci_trans(vsk)->queue_pair_max_size = val;
  	vmci_trans(vsk)->queue_pair_size = val;
  }
  
  static void vmci_transport_set_min_buffer_size(struct vsock_sock *vsk,
  					       u64 val)
  {
  	if (val > vmci_trans(vsk)->queue_pair_size)
  		vmci_trans(vsk)->queue_pair_size = val;
  	vmci_trans(vsk)->queue_pair_min_size = val;
  }
  
  static void vmci_transport_set_max_buffer_size(struct vsock_sock *vsk,
  					       u64 val)
  {
  	if (val < vmci_trans(vsk)->queue_pair_size)
  		vmci_trans(vsk)->queue_pair_size = val;
  	vmci_trans(vsk)->queue_pair_max_size = val;
  }
  
  static int vmci_transport_notify_poll_in(
  	struct vsock_sock *vsk,
  	size_t target,
  	bool *data_ready_now)
  {
  	return vmci_trans(vsk)->notify_ops->poll_in(
  			&vsk->sk, target, data_ready_now);
  }
  
  static int vmci_transport_notify_poll_out(
  	struct vsock_sock *vsk,
  	size_t target,
  	bool *space_available_now)
  {
  	return vmci_trans(vsk)->notify_ops->poll_out(
  			&vsk->sk, target, space_available_now);
  }
  
  static int vmci_transport_notify_recv_init(
  	struct vsock_sock *vsk,
  	size_t target,
  	struct vsock_transport_recv_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->recv_init(
  			&vsk->sk, target,
  			(struct vmci_transport_recv_notify_data *)data);
  }
  
  static int vmci_transport_notify_recv_pre_block(
  	struct vsock_sock *vsk,
  	size_t target,
  	struct vsock_transport_recv_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->recv_pre_block(
  			&vsk->sk, target,
  			(struct vmci_transport_recv_notify_data *)data);
  }
  
  static int vmci_transport_notify_recv_pre_dequeue(
  	struct vsock_sock *vsk,
  	size_t target,
  	struct vsock_transport_recv_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->recv_pre_dequeue(
  			&vsk->sk, target,
  			(struct vmci_transport_recv_notify_data *)data);
  }
  
  static int vmci_transport_notify_recv_post_dequeue(
  	struct vsock_sock *vsk,
  	size_t target,
  	ssize_t copied,
  	bool data_read,
  	struct vsock_transport_recv_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->recv_post_dequeue(
  			&vsk->sk, target, copied, data_read,
  			(struct vmci_transport_recv_notify_data *)data);
  }
  
  static int vmci_transport_notify_send_init(
  	struct vsock_sock *vsk,
  	struct vsock_transport_send_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->send_init(
  			&vsk->sk,
  			(struct vmci_transport_send_notify_data *)data);
  }
  
  static int vmci_transport_notify_send_pre_block(
  	struct vsock_sock *vsk,
  	struct vsock_transport_send_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->send_pre_block(
  			&vsk->sk,
  			(struct vmci_transport_send_notify_data *)data);
  }
  
  static int vmci_transport_notify_send_pre_enqueue(
  	struct vsock_sock *vsk,
  	struct vsock_transport_send_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->send_pre_enqueue(
  			&vsk->sk,
  			(struct vmci_transport_send_notify_data *)data);
  }
  
  static int vmci_transport_notify_send_post_enqueue(
  	struct vsock_sock *vsk,
  	ssize_t written,
  	struct vsock_transport_send_notify_data *data)
  {
  	return vmci_trans(vsk)->notify_ops->send_post_enqueue(
  			&vsk->sk, written,
  			(struct vmci_transport_send_notify_data *)data);
  }
  
  static bool vmci_transport_old_proto_override(bool *old_pkt_proto)
  {
  	if (PROTOCOL_OVERRIDE != -1) {
  		if (PROTOCOL_OVERRIDE == 0)
  			*old_pkt_proto = true;
  		else
  			*old_pkt_proto = false;
  
  		pr_info("Proto override in use
  ");
  		return true;
  	}
  
  	return false;
  }
  
  static bool vmci_transport_proto_to_notify_struct(struct sock *sk,
  						  u16 *proto,
  						  bool old_pkt_proto)
  {
  	struct vsock_sock *vsk = vsock_sk(sk);
  
  	if (old_pkt_proto) {
  		if (*proto != VSOCK_PROTO_INVALID) {
  			pr_err("Can't set both an old and new protocol
  ");
  			return false;
  		}
  		vmci_trans(vsk)->notify_ops = &vmci_transport_notify_pkt_ops;
  		goto exit;
  	}
  
  	switch (*proto) {
  	case VSOCK_PROTO_PKT_ON_NOTIFY:
  		vmci_trans(vsk)->notify_ops =
  			&vmci_transport_notify_pkt_q_state_ops;
  		break;
  	default:
  		pr_err("Unknown notify protocol version
  ");
  		return false;
  	}
  
  exit:
  	vmci_trans(vsk)->notify_ops->socket_init(sk);
  	return true;
  }
  
  static u16 vmci_transport_new_proto_supported_versions(void)
  {
  	if (PROTOCOL_OVERRIDE != -1)
  		return PROTOCOL_OVERRIDE;
  
  	return VSOCK_PROTO_ALL_SUPPORTED;
  }
  
  static u32 vmci_transport_get_local_cid(void)
  {
  	return vmci_get_context_id();
  }
  
  static struct vsock_transport vmci_transport = {
  	.init = vmci_transport_socket_init,
  	.destruct = vmci_transport_destruct,
  	.release = vmci_transport_release,
  	.connect = vmci_transport_connect,
  	.dgram_bind = vmci_transport_dgram_bind,
  	.dgram_dequeue = vmci_transport_dgram_dequeue,
  	.dgram_enqueue = vmci_transport_dgram_enqueue,
  	.dgram_allow = vmci_transport_dgram_allow,
  	.stream_dequeue = vmci_transport_stream_dequeue,
  	.stream_enqueue = vmci_transport_stream_enqueue,
  	.stream_has_data = vmci_transport_stream_has_data,
  	.stream_has_space = vmci_transport_stream_has_space,
  	.stream_rcvhiwat = vmci_transport_stream_rcvhiwat,
  	.stream_is_active = vmci_transport_stream_is_active,
  	.stream_allow = vmci_transport_stream_allow,
  	.notify_poll_in = vmci_transport_notify_poll_in,
  	.notify_poll_out = vmci_transport_notify_poll_out,
  	.notify_recv_init = vmci_transport_notify_recv_init,
  	.notify_recv_pre_block = vmci_transport_notify_recv_pre_block,
  	.notify_recv_pre_dequeue = vmci_transport_notify_recv_pre_dequeue,
  	.notify_recv_post_dequeue = vmci_transport_notify_recv_post_dequeue,
  	.notify_send_init = vmci_transport_notify_send_init,
  	.notify_send_pre_block = vmci_transport_notify_send_pre_block,
  	.notify_send_pre_enqueue = vmci_transport_notify_send_pre_enqueue,
  	.notify_send_post_enqueue = vmci_transport_notify_send_post_enqueue,
  	.shutdown = vmci_transport_shutdown,
  	.set_buffer_size = vmci_transport_set_buffer_size,
  	.set_min_buffer_size = vmci_transport_set_min_buffer_size,
  	.set_max_buffer_size = vmci_transport_set_max_buffer_size,
  	.get_buffer_size = vmci_transport_get_buffer_size,
  	.get_min_buffer_size = vmci_transport_get_min_buffer_size,
  	.get_max_buffer_size = vmci_transport_get_max_buffer_size,
  	.get_local_cid = vmci_transport_get_local_cid,
  };
  
  static int __init vmci_transport_init(void)
  {
  	int err;
  
  	/* Create the datagram handle that we will use to send and receive all
  	 * VSocket control messages for this context.
  	 */
  	err = vmci_transport_datagram_create_hnd(VMCI_TRANSPORT_PACKET_RID,
  						 VMCI_FLAG_ANYCID_DG_HND,
  						 vmci_transport_recv_stream_cb,
  						 NULL,
  						 &vmci_transport_stream_handle);
  	if (err < VMCI_SUCCESS) {
  		pr_err("Unable to create datagram handle. (%d)
  ", err);
  		return vmci_transport_error_to_vsock_error(err);
  	}
  
  	err = vmci_event_subscribe(VMCI_EVENT_QP_RESUMED,
  				   vmci_transport_qp_resumed_cb,
  				   NULL, &vmci_transport_qp_resumed_sub_id);
  	if (err < VMCI_SUCCESS) {
  		pr_err("Unable to subscribe to resumed event. (%d)
  ", err);
  		err = vmci_transport_error_to_vsock_error(err);
  		vmci_transport_qp_resumed_sub_id = VMCI_INVALID_ID;
  		goto err_destroy_stream_handle;
  	}
  
  	err = vsock_core_init(&vmci_transport);
  	if (err < 0)
  		goto err_unsubscribe;
  
  	return 0;
  
  err_unsubscribe:
  	vmci_event_unsubscribe(vmci_transport_qp_resumed_sub_id);
  err_destroy_stream_handle:
  	vmci_datagram_destroy_handle(vmci_transport_stream_handle);
  	return err;
  }
  module_init(vmci_transport_init);
  
  static void __exit vmci_transport_exit(void)
  {
  	cancel_work_sync(&vmci_transport_cleanup_work);
  	vmci_transport_free_resources(&vmci_transport_cleanup_list);
  
  	if (!vmci_handle_is_invalid(vmci_transport_stream_handle)) {
  		if (vmci_datagram_destroy_handle(
  			vmci_transport_stream_handle) != VMCI_SUCCESS)
  			pr_err("Couldn't destroy datagram handle
  ");
  		vmci_transport_stream_handle = VMCI_INVALID_HANDLE;
  	}
  
  	if (vmci_transport_qp_resumed_sub_id != VMCI_INVALID_ID) {
  		vmci_event_unsubscribe(vmci_transport_qp_resumed_sub_id);
  		vmci_transport_qp_resumed_sub_id = VMCI_INVALID_ID;
  	}
  
  	vsock_core_exit();
  }
  module_exit(vmci_transport_exit);
  
  MODULE_AUTHOR("VMware, Inc.");
  MODULE_DESCRIPTION("VMCI transport for Virtual Sockets");
  MODULE_VERSION("1.0.2.0-k");
  MODULE_LICENSE("GPL v2");
  MODULE_ALIAS("vmware_vsock");
  MODULE_ALIAS_NETPROTO(PF_VSOCK);