Merge branch 'vsock-virtio'

Stefan Hajnoczi says:

====================
Add virtio transport for AF_VSOCK

v2:
 * Rebased onto Linux v4.4-rc2
 * vhost: Refuse to assign reserved CIDs
 * vhost: Refuse guest CID if already in use
 * vhost: Only accept correctly addressed packets (no spoofing!)
 * vhost: Support flexible rx/tx descriptor layout
 * vhost: Add missing total_tx_buf decrement
 * virtio_transport: Fix total_tx_buf accounting
 * virtio_transport: Add virtio_transport global mutex to prevent races
 * common: Notify other side of SOCK_STREAM disconnect (fixes shutdown
   semantics)
 * common: Avoid recursive mutex_lock(tx_lock) for write_space (fixes deadlock)
 * common: Define VIRTIO_VSOCK_TYPE_STREAM/DGRAM hardware interface constants
 * common: Define VIRTIO_VSOCK_SHUTDOWN_RCV/SEND hardware interface constants
 * common: Fix peer_buf_alloc inheritance on child socket

This patch series adds a virtio transport for AF_VSOCK (net/vmw_vsock/).
AF_VSOCK is designed for communication between virtual machines and
hypervisors.  It is currently only implemented for VMware's VMCI transport.

This series implements the proposed virtio-vsock device specification from
here:
http://comments.gmane.org/gmane.comp.emulators.virtio.devel/855

Most of the work was done by Asias He and Gerd Hoffmann a while back.  I have
picked up the series again.

The QEMU userspace changes are here:
https://github.com/stefanha/qemu/commits/vsock

Why virtio-vsock?
-----------------
Guest<->host communication is currently done over the virtio-serial device.
This makes it hard to port sockets API-based applications and is limited to
static ports.

virtio-vsock uses the sockets API so that applications can rely on familiar
SOCK_STREAM and SOCK_DGRAM semantics.  Applications on the host can easily
connect to guest agents because the sockets API allows multiple connections to
a listen socket (unlike virtio-serial).  This simplifies the guest<->host
communication and eliminates the need for extra processes on the host to
arbitrate virtio-serial ports.

Overview
--------
This series adds 3 pieces:

1. virtio_transport_common.ko - core virtio vsock code that uses vsock.ko

2. virtio_transport.ko - guest driver

3. drivers/vhost/vsock.ko - host driver

Howto
-----
The following kernel options are needed:
  CONFIG_VSOCKETS=y
  CONFIG_VIRTIO_VSOCKETS=y
  CONFIG_VIRTIO_VSOCKETS_COMMON=y
  CONFIG_VHOST_VSOCK=m

Launch QEMU as follows:
  # qemu ... -device vhost-vsock-pci,id=vhost-vsock-pci0,guest-cid=3

Guest and host can communicate via AF_VSOCK sockets.  The host's CID (address)
is 2 and the guest is automatically assigned a CID (use VMADDR_CID_ANY (-1) to
bind to it).

Status
------
There are a few design changes I'd like to make to the virtio-vsock device:

1. The 3-way handshake isn't necessary over a reliable transport (virtqueue).
   Spoofing packets is also impossible so the security aspects of the 3-way
   handshake (including syn cookie) add nothing.  The next version will have a
   single operation to establish a connection.

2. Credit-based flow control doesn't work for SOCK_DGRAM since multiple clients
   can transmit to the same listen socket.  There is no way for the clients to
   coordinate buffer space with each other fairly.  The next version will drop
   credit-based flow control for SOCK_DGRAM and only rely on best-effort
   delivery.  SOCK_STREAM still has guaranteed delivery.

3. In the next version only the host will be able to establish connections
   (i.e. to connect to a guest agent).  This is for security reasons since
   there is currently no ability to provide host services only to certain
   guests.  This also matches how AF_VSOCK works on modern VMware hypervisors.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 1828 insertions, 0 deletions

diff --git a/net/vmw_vsock/Kconfig b/net/vmw_vsock/Kconfig
index 14810abedc2e..74e0bc887a33 100644
--- a/net/vmw_vsock/Kconfig
+++ b/net/vmw_vsock/Kconfig
@@ -26,3 +26,21 @@ config VMWARE_VMCI_VSOCKETS
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called vmw_vsock_vmci_transport. If unsure, say N.
+
+config VIRTIO_VSOCKETS
+	tristate "virtio transport for Virtual Sockets"
+	depends on VSOCKETS && VIRTIO
+	select VIRTIO_VSOCKETS_COMMON
+	help
+	  This module implements a virtio transport for Virtual Sockets.
+
+	  Enable this transport if your Virtual Machine runs on Qemu/KVM.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called virtio_vsock_transport. If unsure, say N.
+
+config VIRTIO_VSOCKETS_COMMON
+       tristate
+       ---help---
+         This option is selected by any driver which needs to access
+         the virtio_vsock.
diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
index 2ce52d70f224..cf4c29439081 100644
--- a/net/vmw_vsock/Makefile
+++ b/net/vmw_vsock/Makefile
@@ -1,5 +1,7 @@
 obj-$(CONFIG_VSOCKETS) += vsock.o
 obj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o
+obj-$(CONFIG_VIRTIO_VSOCKETS) += virtio_transport.o
+obj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += virtio_transport_common.o
 
 vsock-y += af_vsock.o vsock_addr.o
 
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 7fd1220fbfa0..77247a2b670b 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -223,6 +223,17 @@ static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
 	return NULL;
 }
 
+static struct sock *__vsock_find_unbound_socket(struct sockaddr_vm *addr)
+{
+	struct vsock_sock *vsk;
+
+	list_for_each_entry(vsk, vsock_unbound_sockets, 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)
 {
@@ -298,6 +309,21 @@ struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr)
 }
 EXPORT_SYMBOL_GPL(vsock_find_bound_socket);
 
+struct sock *vsock_find_unbound_socket(struct sockaddr_vm *addr)
+{
+	struct sock *sk;
+
+	spin_lock_bh(&vsock_table_lock);
+	sk = __vsock_find_unbound_socket(addr);
+	if (sk)
+		sock_hold(sk);
+
+	spin_unlock_bh(&vsock_table_lock);
+
+	return sk;
+}
+EXPORT_SYMBOL_GPL(vsock_find_unbound_socket);
+
 struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
 					 struct sockaddr_vm *dst)
 {
@@ -532,6 +558,50 @@ static int __vsock_bind_stream(struct vsock_sock *vsk,
 	return 0;
 }
 
+int vsock_bind_dgram_generic(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_unbound_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_unbound_socket(&new_addr))
+			return -EADDRINUSE;
+	}
+
+	vsock_addr_init(&vsk->local_addr, new_addr.svm_cid, new_addr.svm_port);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vsock_bind_dgram_generic);
+
 static int __vsock_bind_dgram(struct vsock_sock *vsk,
 			      struct sockaddr_vm *addr)
 {
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
new file mode 100644
index 000000000000..df65dca55fa1
--- /dev/null
+++ b/net/vmw_vsock/virtio_transport.c
@@ -0,0 +1,466 @@
+/*
+ * virtio transport for vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias@redhat.com>
+ *         Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s
+ * early virtio-vsock proof-of-concept bits.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_vsock.h>
+#include <net/sock.h>
+#include <linux/mutex.h>
+#include <net/af_vsock.h>
+
+static struct workqueue_struct *virtio_vsock_workqueue;
+static struct virtio_vsock *the_virtio_vsock;
+static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock);
+
+struct virtio_vsock {
+	/* Virtio device */
+	struct virtio_device *vdev;
+	/* Virtio virtqueue */
+	struct virtqueue *vqs[VSOCK_VQ_MAX];
+	/* Wait queue for send pkt */
+	wait_queue_head_t queue_wait;
+	/* Work item to send pkt */
+	struct work_struct tx_work;
+	/* Work item to recv pkt */
+	struct work_struct rx_work;
+	/* Mutex to protect send pkt*/
+	struct mutex tx_lock;
+	/* Mutex to protect recv pkt*/
+	struct mutex rx_lock;
+	/* Number of recv buffers */
+	int rx_buf_nr;
+	/* Number of max recv buffers */
+	int rx_buf_max_nr;
+	/* Used for global tx buf limitation */
+	u32 total_tx_buf;
+	/* Guest context id, just like guest ip address */
+	u32 guest_cid;
+};
+
+static struct virtio_vsock *virtio_vsock_get(void)
+{
+	return the_virtio_vsock;
+}
+
+static u32 virtio_transport_get_local_cid(void)
+{
+	struct virtio_vsock *vsock = virtio_vsock_get();
+
+	return vsock->guest_cid;
+}
+
+static int
+virtio_transport_send_pkt(struct vsock_sock *vsk,
+			  struct virtio_vsock_pkt_info *info)
+{
+	u32 src_cid, src_port, dst_cid, dst_port;
+	int ret, in_sg = 0, out_sg = 0;
+	struct virtio_transport *trans;
+	struct virtio_vsock_pkt *pkt;
+	struct virtio_vsock *vsock;
+	struct scatterlist hdr, buf, *sgs[2];
+	struct virtqueue *vq;
+	u32 pkt_len = info->pkt_len;
+	DEFINE_WAIT(wait);
+
+	vsock = virtio_vsock_get();
+	if (!vsock)
+		return -ENODEV;
+
+	src_cid	= virtio_transport_get_local_cid();
+	src_port = vsk->local_addr.svm_port;
+	if (!info->remote_cid) {
+		dst_cid	= vsk->remote_addr.svm_cid;
+		dst_port = vsk->remote_addr.svm_port;
+	} else {
+		dst_cid = info->remote_cid;
+		dst_port = info->remote_port;
+	}
+
+	trans = vsk->trans;
+	vq = vsock->vqs[VSOCK_VQ_TX];
+
+	if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+		pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+	pkt_len = virtio_transport_get_credit(trans, pkt_len);
+	/* Do not send zero length OP_RW pkt*/
+	if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
+		return pkt_len;
+
+	/* Respect global tx buf limitation */
+	mutex_lock(&vsock->tx_lock);
+	while (pkt_len + vsock->total_tx_buf > VIRTIO_VSOCK_MAX_TX_BUF_SIZE) {
+		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+					  TASK_UNINTERRUPTIBLE);
+		mutex_unlock(&vsock->tx_lock);
+		schedule();
+		mutex_lock(&vsock->tx_lock);
+		finish_wait(&vsock->queue_wait, &wait);
+	}
+	vsock->total_tx_buf += pkt_len;
+	mutex_unlock(&vsock->tx_lock);
+
+	pkt = virtio_transport_alloc_pkt(vsk, info, pkt_len,
+					 src_cid, src_port,
+					 dst_cid, dst_port);
+	if (!pkt) {
+		mutex_lock(&vsock->tx_lock);
+		vsock->total_tx_buf -= pkt_len;
+		mutex_unlock(&vsock->tx_lock);
+		virtio_transport_put_credit(trans, pkt_len);
+		return -ENOMEM;
+	}
+
+	pr_debug("%s:info->pkt_len= %d\n", __func__, info->pkt_len);
+
+	/* Will be released in virtio_transport_send_pkt_work */
+	sock_hold(&trans->vsk->sk);
+	virtio_transport_inc_tx_pkt(pkt);
+
+	/* Put pkt in the virtqueue */
+	sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+	sgs[out_sg++] = &hdr;
+	if (info->msg && info->pkt_len > 0) {
+		sg_init_one(&buf, pkt->buf, pkt->len);
+	        sgs[out_sg++] = &buf;
+	}
+
+	mutex_lock(&vsock->tx_lock);
+	while ((ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt,
+					GFP_KERNEL)) < 0) {
+		prepare_to_wait_exclusive(&vsock->queue_wait, &wait,
+					  TASK_UNINTERRUPTIBLE);
+		mutex_unlock(&vsock->tx_lock);
+		schedule();
+		mutex_lock(&vsock->tx_lock);
+		finish_wait(&vsock->queue_wait, &wait);
+	}
+	virtqueue_kick(vq);
+	mutex_unlock(&vsock->tx_lock);
+
+	return pkt_len;
+}
+
+static struct virtio_transport_pkt_ops virtio_ops = {
+	.send_pkt = virtio_transport_send_pkt,
+};
+
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
+{
+	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+	struct virtio_vsock_pkt *pkt;
+	struct scatterlist hdr, buf, *sgs[2];
+	struct virtqueue *vq;
+	int ret;
+
+	vq = vsock->vqs[VSOCK_VQ_RX];
+
+	do {
+		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+		if (!pkt) {
+			pr_debug("%s: fail to allocate pkt\n", __func__);
+			goto out;
+		}
+
+		/* TODO: use mergeable rx buffer */
+		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
+		if (!pkt->buf) {
+			pr_debug("%s: fail to allocate pkt->buf\n", __func__);
+			goto err;
+		}
+
+		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+		sgs[0] = &hdr;
+
+		sg_init_one(&buf, pkt->buf, buf_len);
+	        sgs[1] = &buf;
+		ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
+		if (ret)
+			goto err;
+		vsock->rx_buf_nr++;
+	} while (vq->num_free);
+	if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
+		vsock->rx_buf_max_nr = vsock->rx_buf_nr;
+out:
+	virtqueue_kick(vq);
+	return;
+err:
+	virtqueue_kick(vq);
+	virtio_transport_free_pkt(pkt);
+	return;
+}
+
+static void virtio_transport_send_pkt_work(struct work_struct *work)
+{
+	struct virtio_vsock *vsock =
+		container_of(work, struct virtio_vsock, tx_work);
+	struct virtio_vsock_pkt *pkt;
+	bool added = false;
+	struct virtqueue *vq;
+	unsigned int len;
+	struct sock *sk;
+
+	vq = vsock->vqs[VSOCK_VQ_TX];
+	mutex_lock(&vsock->tx_lock);
+	do {
+		virtqueue_disable_cb(vq);
+		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+			sk = &pkt->trans->vsk->sk;
+			virtio_transport_dec_tx_pkt(pkt);
+			/* Release refcnt taken in virtio_transport_send_pkt */
+			sock_put(sk);
+			vsock->total_tx_buf -= pkt->len;
+			virtio_transport_free_pkt(pkt);
+			added = true;
+		}
+	} while (!virtqueue_enable_cb(vq));
+	mutex_unlock(&vsock->tx_lock);
+
+	if (added)
+		wake_up(&vsock->queue_wait);
+}
+
+static void virtio_transport_recv_pkt_work(struct work_struct *work)
+{
+	struct virtio_vsock *vsock =
+		container_of(work, struct virtio_vsock, rx_work);
+	struct virtio_vsock_pkt *pkt;
+	struct virtqueue *vq;
+	unsigned int len;
+
+	vq = vsock->vqs[VSOCK_VQ_RX];
+	mutex_lock(&vsock->rx_lock);
+	do {
+		virtqueue_disable_cb(vq);
+		while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
+			pkt->len = len;
+			virtio_transport_recv_pkt(pkt);
+			vsock->rx_buf_nr--;
+		}
+	} while (!virtqueue_enable_cb(vq));
+
+	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
+		virtio_vsock_rx_fill(vsock);
+	mutex_unlock(&vsock->rx_lock);
+}
+
+static void virtio_vsock_ctrl_done(struct virtqueue *vq)
+{
+}
+
+static void virtio_vsock_tx_done(struct virtqueue *vq)
+{
+	struct virtio_vsock *vsock = vq->vdev->priv;
+
+	if (!vsock)
+		return;
+	queue_work(virtio_vsock_workqueue, &vsock->tx_work);
+}
+
+static void virtio_vsock_rx_done(struct virtqueue *vq)
+{
+	struct virtio_vsock *vsock = vq->vdev->priv;
+
+	if (!vsock)
+		return;
+	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
+}
+
+static int
+virtio_transport_socket_init(struct vsock_sock *vsk, struct vsock_sock *psk)
+{
+	struct virtio_transport *trans;
+	int ret;
+
+	ret = virtio_transport_do_socket_init(vsk, psk);
+	if (ret)
+		return ret;
+
+	trans = vsk->trans;
+	trans->ops = &virtio_ops;
+	return ret;
+}
+
+static struct vsock_transport virtio_transport = {
+	.get_local_cid            = virtio_transport_get_local_cid,
+
+	.init                     = virtio_transport_socket_init,
+	.destruct                 = virtio_transport_destruct,
+	.release                  = virtio_transport_release,
+	.connect                  = virtio_transport_connect,
+	.shutdown                 = virtio_transport_shutdown,
+
+	.dgram_bind               = virtio_transport_dgram_bind,
+	.dgram_dequeue            = virtio_transport_dgram_dequeue,
+	.dgram_enqueue            = virtio_transport_dgram_enqueue,
+	.dgram_allow              = virtio_transport_dgram_allow,
+
+	.stream_dequeue           = virtio_transport_stream_dequeue,
+	.stream_enqueue           = virtio_transport_stream_enqueue,
+	.stream_has_data          = virtio_transport_stream_has_data,
+	.stream_has_space         = virtio_transport_stream_has_space,
+	.stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
+	.stream_is_active         = virtio_transport_stream_is_active,
+	.stream_allow             = virtio_transport_stream_allow,
+
+	.notify_poll_in           = virtio_transport_notify_poll_in,
+	.notify_poll_out          = virtio_transport_notify_poll_out,
+	.notify_recv_init         = virtio_transport_notify_recv_init,
+	.notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
+	.notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
+	.notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
+	.notify_send_init         = virtio_transport_notify_send_init,
+	.notify_send_pre_block    = virtio_transport_notify_send_pre_block,
+	.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
+	.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
+
+	.set_buffer_size          = virtio_transport_set_buffer_size,
+	.set_min_buffer_size      = virtio_transport_set_min_buffer_size,
+	.set_max_buffer_size      = virtio_transport_set_max_buffer_size,
+	.get_buffer_size          = virtio_transport_get_buffer_size,
+	.get_min_buffer_size      = virtio_transport_get_min_buffer_size,
+	.get_max_buffer_size      = virtio_transport_get_max_buffer_size,
+};
+
+static int virtio_vsock_probe(struct virtio_device *vdev)
+{
+	vq_callback_t *callbacks[] = {
+		virtio_vsock_ctrl_done,
+		virtio_vsock_rx_done,
+		virtio_vsock_tx_done,
+	};
+	const char *names[] = {
+		"ctrl",
+		"rx",
+		"tx",
+	};
+	struct virtio_vsock *vsock = NULL;
+	u32 guest_cid;
+	int ret;
+
+	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
+	if (ret)
+		return ret;
+
+	/* Only one virtio-vsock device per guest is supported */
+	if (the_virtio_vsock) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+	if (!vsock) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	vsock->vdev = vdev;
+
+	ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX,
+					    vsock->vqs, callbacks, names);
+	if (ret < 0)
+		goto out;
+
+	vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
+			  &guest_cid, sizeof(guest_cid));
+	vsock->guest_cid = le32_to_cpu(guest_cid);
+	pr_debug("%s:guest_cid=%d\n", __func__, vsock->guest_cid);
+
+	ret = vsock_core_init(&virtio_transport);
+	if (ret < 0)
+		goto out_vqs;
+
+	vsock->rx_buf_nr = 0;
+	vsock->rx_buf_max_nr = 0;
+
+	vdev->priv = the_virtio_vsock = vsock;
+	init_waitqueue_head(&vsock->queue_wait);
+	mutex_init(&vsock->tx_lock);
+	mutex_init(&vsock->rx_lock);
+	INIT_WORK(&vsock->rx_work, virtio_transport_recv_pkt_work);
+	INIT_WORK(&vsock->tx_work, virtio_transport_send_pkt_work);
+
+	mutex_lock(&vsock->rx_lock);
+	virtio_vsock_rx_fill(vsock);
+	mutex_unlock(&vsock->rx_lock);
+
+	mutex_unlock(&the_virtio_vsock_mutex);
+	return 0;
+
+out_vqs:
+	vsock->vdev->config->del_vqs(vsock->vdev);
+out:
+	kfree(vsock);
+	mutex_unlock(&the_virtio_vsock_mutex);
+	return ret;
+}
+
+static void virtio_vsock_remove(struct virtio_device *vdev)
+{
+	struct virtio_vsock *vsock = vdev->priv;
+
+	mutex_lock(&the_virtio_vsock_mutex);
+	the_virtio_vsock = NULL;
+	vsock_core_exit();
+	mutex_unlock(&the_virtio_vsock_mutex);
+
+	kfree(vsock);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static unsigned int features[] = {
+};
+
+static struct virtio_driver virtio_vsock_driver = {
+	.feature_table = features,
+	.feature_table_size = ARRAY_SIZE(features),
+	.driver.name = KBUILD_MODNAME,
+	.driver.owner = THIS_MODULE,
+	.id_table = id_table,
+	.probe = virtio_vsock_probe,
+	.remove = virtio_vsock_remove,
+};
+
+static int __init virtio_vsock_init(void)
+{
+	int ret;
+
+	virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
+	if (!virtio_vsock_workqueue)
+		return -ENOMEM;
+	ret = register_virtio_driver(&virtio_vsock_driver);
+	if (ret)
+		destroy_workqueue(virtio_vsock_workqueue);
+	return ret;
+}
+
+static void __exit virtio_vsock_exit(void)
+{
+	unregister_virtio_driver(&virtio_vsock_driver);
+	destroy_workqueue(virtio_vsock_workqueue);
+}
+
+module_init(virtio_vsock_init);
+module_exit(virtio_vsock_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("virtio transport for vsock");
+MODULE_DEVICE_TABLE(virtio, id_table);
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
new file mode 100644
index 000000000000..28f790da6f15
--- /dev/null
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -0,0 +1,1272 @@
+/*
+ * common code for virtio vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias@redhat.com>
+ *         Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_vsock.h>
+#include <linux/random.h>
+#include <linux/cryptohash.h>
+
+#include <net/sock.h>
+#include <net/af_vsock.h>
+
+#define COOKIEBITS 24
+#define COOKIEMASK (((u32)1 << COOKIEBITS) - 1)
+#define VSOCK_TIMEOUT_INIT 4
+
+#define SHA_MESSAGE_WORDS 16
+#define SHA_VSOCK_WORDS 5
+
+static u32 vsockcookie_secret[2][SHA_MESSAGE_WORDS - SHA_VSOCK_WORDS +
+				 SHA_DIGEST_WORDS];
+
+static DEFINE_PER_CPU(__u32[SHA_MESSAGE_WORDS + SHA_DIGEST_WORDS +
+		      SHA_WORKSPACE_WORDS], vsock_cookie_scratch);
+
+static u32 cookie_hash(u32 saddr, u32 daddr, u16 sport, u16 dport,
+		       u32 count, int c)
+{
+	__u32 *tmp = this_cpu_ptr(vsock_cookie_scratch);
+
+	memcpy(tmp + SHA_VSOCK_WORDS, vsockcookie_secret[c],
+	       sizeof(vsockcookie_secret[c]));
+	tmp[0] = saddr;
+	tmp[1] = daddr;
+	tmp[2] = sport;
+	tmp[3] = dport;
+	tmp[4] = count;
+	sha_transform(tmp + SHA_MESSAGE_WORDS, (__u8 *)tmp,
+		      tmp + SHA_MESSAGE_WORDS + SHA_DIGEST_WORDS);
+
+	return tmp[17];
+}
+
+static u32
+virtio_vsock_secure_cookie(u32 saddr, u32 daddr, u32 sport, u32 dport,
+			   u32 count)
+{
+	u32 h1, h2;
+
+	h1 = cookie_hash(saddr, daddr, sport, dport, 0, 0);
+	h2 = cookie_hash(saddr, daddr, sport, dport, count, 1);
+
+	return h1 + (count << COOKIEBITS) + (h2 & COOKIEMASK);
+}
+
+static u32
+virtio_vsock_check_cookie(u32 saddr, u32 daddr, u32 sport, u32 dport,
+			  u32 count, u32 cookie, u32 maxdiff)
+{
+	u32 diff;
+	u32 ret;
+
+	cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0);
+
+	diff = (count - (cookie >> COOKIEBITS)) & ((u32)-1 >> COOKIEBITS);
+	pr_debug("%s: diff=%x\n", __func__, diff);
+	if (diff >= maxdiff)
+		return (u32)-1;
+
+	ret = (cookie -
+		cookie_hash(saddr, daddr, sport, dport, count - diff, 1))
+		& COOKIEMASK;
+	pr_debug("%s: ret=%x\n", __func__, diff);
+
+	return ret;
+}
+
+void virtio_vsock_dumppkt(const char *func,  const struct virtio_vsock_pkt *pkt)
+{
+	pr_debug("%s: pkt=%p, op=%d, len=%d, %d:%d---%d:%d, len=%d\n",
+		 func, pkt,
+		 le16_to_cpu(pkt->hdr.op),
+		 le32_to_cpu(pkt->hdr.len),
+		 le32_to_cpu(pkt->hdr.src_cid),
+		 le32_to_cpu(pkt->hdr.src_port),
+		 le32_to_cpu(pkt->hdr.dst_cid),
+		 le32_to_cpu(pkt->hdr.dst_port),
+		 pkt->len);
+}
+EXPORT_SYMBOL_GPL(virtio_vsock_dumppkt);
+
+struct virtio_vsock_pkt *
+virtio_transport_alloc_pkt(struct vsock_sock *vsk,
+			   struct virtio_vsock_pkt_info *info,
+			   size_t len,
+			   u32 src_cid,
+			   u32 src_port,
+			   u32 dst_cid,
+			   u32 dst_port)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt *pkt;
+	int err;
+
+	BUG_ON(!trans);
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt)
+		return NULL;
+
+	pkt->hdr.type		= cpu_to_le16(info->type);
+	pkt->hdr.op		= cpu_to_le16(info->op);
+	pkt->hdr.src_cid	= cpu_to_le32(src_cid);
+	pkt->hdr.src_port	= cpu_to_le32(src_port);
+	pkt->hdr.dst_cid	= cpu_to_le32(dst_cid);
+	pkt->hdr.dst_port	= cpu_to_le32(dst_port);
+	pkt->hdr.flags		= cpu_to_le32(info->flags);
+	pkt->len		= len;
+	pkt->trans		= trans;
+	if (info->type == VIRTIO_VSOCK_TYPE_DGRAM)
+		pkt->hdr.len	= cpu_to_le32(len + (info->dgram_len << 16));
+	else if (info->type == VIRTIO_VSOCK_TYPE_STREAM)
+		pkt->hdr.len	= cpu_to_le32(len);
+
+	if (info->msg && len > 0) {
+		pkt->buf = kmalloc(len, GFP_KERNEL);
+		if (!pkt->buf)
+			goto out_pkt;
+		err = memcpy_from_msg(pkt->buf, info->msg, len);
+		if (err)
+			goto out;
+	}
+
+	return pkt;
+
+out:
+	kfree(pkt->buf);
+out_pkt:
+	kfree(pkt);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_alloc_pkt);
+
+struct sock *
+virtio_transport_get_pending(struct sock *listener,
+			     struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vlistener;
+	struct vsock_sock *vpending;
+	struct sockaddr_vm src;
+	struct sockaddr_vm dst;
+	struct sock *pending;
+
+	vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid), le32_to_cpu(pkt->hdr.src_port));
+	vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid), le32_to_cpu(pkt->hdr.dst_port));
+
+	vlistener = vsock_sk(listener);
+	list_for_each_entry(vpending, &vlistener->pending_links,
+			    pending_links) {
+		if (vsock_addr_equals_addr(&src, &vpending->remote_addr) &&
+		    vsock_addr_equals_addr(&dst, &vpending->local_addr)) {
+			pending = sk_vsock(vpending);
+			sock_hold(pending);
+			return pending;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_pending);
+
+static void virtio_transport_inc_rx_pkt(struct virtio_vsock_pkt *pkt)
+{
+	pkt->trans->rx_bytes += pkt->len;
+}
+
+static void virtio_transport_dec_rx_pkt(struct virtio_vsock_pkt *pkt)
+{
+	pkt->trans->rx_bytes -= pkt->len;
+	pkt->trans->fwd_cnt += pkt->len;
+}
+
+void virtio_transport_inc_tx_pkt(struct virtio_vsock_pkt *pkt)
+{
+	mutex_lock(&pkt->trans->tx_lock);
+	pkt->hdr.fwd_cnt = cpu_to_le32(pkt->trans->fwd_cnt);
+	pkt->hdr.buf_alloc = cpu_to_le32(pkt->trans->buf_alloc);
+	mutex_unlock(&pkt->trans->tx_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
+
+void virtio_transport_dec_tx_pkt(struct virtio_vsock_pkt *pkt)
+{
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dec_tx_pkt);
+
+u32 virtio_transport_get_credit(struct virtio_transport *trans, u32 credit)
+{
+	u32 ret;
+
+	mutex_lock(&trans->tx_lock);
+	ret = trans->peer_buf_alloc - (trans->tx_cnt - trans->peer_fwd_cnt);
+	if (ret > credit)
+		ret = credit;
+	trans->tx_cnt += ret;
+	mutex_unlock(&trans->tx_lock);
+
+	pr_debug("%s: ret=%d, buf_alloc=%d, peer_buf_alloc=%d,"
+		 "tx_cnt=%d, fwd_cnt=%d, peer_fwd_cnt=%d\n", __func__,
+		 ret, trans->buf_alloc, trans->peer_buf_alloc,
+		 trans->tx_cnt, trans->fwd_cnt, trans->peer_fwd_cnt);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
+
+void virtio_transport_put_credit(struct virtio_transport *trans, u32 credit)
+{
+	mutex_lock(&trans->tx_lock);
+	trans->tx_cnt -= credit;
+	mutex_unlock(&trans->tx_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
+
+static int virtio_transport_send_credit_update(struct vsock_sock *vsk, int type, struct virtio_vsock_hdr *hdr)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
+		.type = type,
+	};
+
+	if (hdr && type == VIRTIO_VSOCK_TYPE_DGRAM) {
+		info.remote_cid = le32_to_cpu(hdr->src_cid);
+		info.remote_port = le32_to_cpu(hdr->src_port);
+	}
+
+	pr_debug("%s: sk=%p send_credit_update\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static int virtio_transport_send_credit_request(struct vsock_sock *vsk, int type)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_CREDIT_REQUEST,
+		.type = type,
+	};
+
+	pr_debug("%s: sk=%p send_credit_request\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static ssize_t
+virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
+				   struct msghdr *msg,
+				   size_t len)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt *pkt;
+	size_t bytes, total = 0;
+	int err = -EFAULT;
+
+	mutex_lock(&trans->rx_lock);
+	while (total < len && trans->rx_bytes > 0  &&
+			!list_empty(&trans->rx_queue)) {
+		pkt = list_first_entry(&trans->rx_queue,
+				       struct virtio_vsock_pkt, list);
+
+		bytes = len - total;
+		if (bytes > pkt->len - pkt->off)
+			bytes = pkt->len - pkt->off;
+
+		err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
+		if (err)
+			goto out;
+		total += bytes;
+		pkt->off += bytes;
+		if (pkt->off == pkt->len) {
+			virtio_transport_dec_rx_pkt(pkt);
+			list_del(&pkt->list);
+			virtio_transport_free_pkt(pkt);
+		}
+	}
+	mutex_unlock(&trans->rx_lock);
+
+	/* Send a credit pkt to peer */
+	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
+					    NULL);
+
+	return total;
+
+out:
+	mutex_unlock(&trans->rx_lock);
+	if (total)
+		err = total;
+	return err;
+}
+
+ssize_t
+virtio_transport_stream_dequeue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len, int flags)
+{
+	if (flags & MSG_PEEK)
+		return -EOPNOTSUPP;
+
+	return virtio_transport_stream_do_dequeue(vsk, msg, len);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
+
+struct dgram_skb {
+	struct list_head list;
+	struct sk_buff *skb;
+	u16 id;
+};
+
+static struct dgram_skb *dgram_id_to_skb(struct virtio_transport *trans,
+					 u16 id)
+{
+	struct dgram_skb *dgram_skb;
+
+	list_for_each_entry(dgram_skb, &trans->incomplete_dgrams, list) {
+		if (dgram_skb->id == id)
+			return dgram_skb;
+	}
+
+	return NULL;
+}
+
+static void
+virtio_transport_recv_dgram(struct sock *sk,
+			    struct virtio_vsock_pkt *pkt)
+{
+	struct sk_buff *skb = NULL;
+	struct vsock_sock *vsk;
+	struct virtio_transport *trans;
+	size_t size;
+	u16 dgram_id, pkt_off, dgram_len, pkt_len;
+	u32 flags, len;
+	struct dgram_skb *dgram_skb;
+
+	vsk = vsock_sk(sk);
+	trans = vsk->trans;
+
+	/* len:   dgram_len | pkt_len */
+	len = le32_to_cpu(pkt->hdr.len);
+	dgram_len = len >> 16;
+	pkt_len = len & 0xFFFF;
+
+	/* flags: dgram_id  | pkt_off */
+	flags = le32_to_cpu(pkt->hdr.flags);
+	dgram_id = flags >> 16;
+	pkt_off = flags & 0xFFFF;
+
+	pr_debug("%s: dgram_len=%d, pkt_len=%d, id=%d, off=%d\n", __func__,
+		 dgram_len, pkt_len, dgram_id, pkt_off);
+
+	dgram_skb = dgram_id_to_skb(trans, dgram_id);
+	if (dgram_skb) {
+		/* This pkt is for a existing dgram */
+		skb = dgram_skb->skb;
+		pr_debug("%s:found skb\n", __func__);
+	}
+
+	/* Packet payload must be within datagram bounds */
+	if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+		goto drop;
+	if (pkt_len > dgram_len)
+		goto drop;
+	if (pkt_off > dgram_len)
+		goto drop;
+	if (dgram_len - pkt_off < pkt_len)
+		goto drop;
+
+	if (!skb) {
+		/* This pkt is for a new dgram */
+		pr_debug("%s:create skb\n", __func__);
+
+		size = sizeof(pkt->hdr) + dgram_len;
+		/* Attach the packet to the socket's receive queue as an sk_buff. */
+		dgram_skb = kzalloc(sizeof(struct dgram_skb), GFP_ATOMIC);
+		if (!dgram_skb)
+			goto drop;
+
+		skb = alloc_skb(size, GFP_ATOMIC);
+		if (!skb) {
+			kfree(dgram_skb);
+			dgram_skb = NULL;
+			goto drop;
+		}
+		dgram_skb->id = dgram_id;
+		dgram_skb->skb = skb;
+		list_add_tail(&dgram_skb->list, &trans->incomplete_dgrams);
+
+		/* sk_receive_skb() will do a sock_put(), so hold here. */
+		sock_hold(sk);
+		skb_put(skb, size);
+		memcpy(skb->data, &pkt->hdr, sizeof(pkt->hdr));
+	}
+
+	memcpy(skb->data + sizeof(pkt->hdr) + pkt_off, pkt->buf, pkt_len);
+
+	pr_debug("%s:C, off=%d, pkt_len=%d, dgram_len=%d\n", __func__,
+		 pkt_off, pkt_len, dgram_len);
+
+	/* We are done with this dgram */
+	if (pkt_off + pkt_len == dgram_len) {
+		pr_debug("%s:dgram_id=%d is done\n", __func__, dgram_id);
+		list_del(&dgram_skb->list);
+		kfree(dgram_skb);
+		sk_receive_skb(sk, skb, 0);
+	}
+	virtio_transport_free_pkt(pkt);
+	return;
+
+drop:
+	if (dgram_skb) {
+		list_del(&dgram_skb->list);
+		kfree(dgram_skb);
+		kfree_skb(skb);
+		sock_put(sk);
+	}
+	virtio_transport_free_pkt(pkt);
+}
+
+int
+virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
+			       struct msghdr *msg,
+			       size_t len, int flags)
+{
+	struct virtio_vsock_hdr *hdr;
+	struct sk_buff *skb;
+	int noblock;
+	int err;
+	int dgram_len;
+
+	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;
+
+	hdr = (struct virtio_vsock_hdr *)skb->data;
+	if (!hdr)
+		goto out;
+
+	dgram_len = le32_to_cpu(hdr->len) >> 16;
+	/* Place the datagram payload in the user's iovec. */
+	err = skb_copy_datagram_msg(skb, sizeof(*hdr), msg, dgram_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, le32_to_cpu(hdr->src_cid), le32_to_cpu(hdr->src_port));
+		msg->msg_namelen = sizeof(*vm_addr);
+	}
+	err = dgram_len;
+
+	/* Send a credit pkt to peer */
+	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_DGRAM, hdr);
+
+	pr_debug("%s:done, recved =%d\n", __func__, dgram_len);
+out:
+	skb_free_datagram(&vsk->sk, skb);
+	return err;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
+
+s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	s64 bytes;
+
+	mutex_lock(&trans->rx_lock);
+	bytes = trans->rx_bytes;
+	mutex_unlock(&trans->rx_lock);
+
+	return bytes;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
+
+static s64 virtio_transport_has_space(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	s64 bytes;
+
+	bytes = trans->peer_buf_alloc - (trans->tx_cnt - trans->peer_fwd_cnt);
+	if (bytes < 0)
+		bytes = 0;
+
+	return bytes;
+}
+
+s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	s64 bytes;
+
+	mutex_lock(&trans->tx_lock);
+	bytes = virtio_transport_has_space(vsk);
+	mutex_unlock(&trans->tx_lock);
+
+	pr_debug("%s: bytes=%lld\n", __func__, bytes);
+
+	return bytes;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
+
+int virtio_transport_do_socket_init(struct vsock_sock *vsk,
+				    struct vsock_sock *psk)
+{
+	struct virtio_transport *trans;
+
+	trans = kzalloc(sizeof(*trans), GFP_KERNEL);
+	if (!trans)
+		return -ENOMEM;
+
+	vsk->trans = trans;
+	trans->vsk = vsk;
+	if (psk) {
+		struct virtio_transport *ptrans = psk->trans;
+		trans->buf_size	= ptrans->buf_size;
+		trans->buf_size_min = ptrans->buf_size_min;
+		trans->buf_size_max = ptrans->buf_size_max;
+		trans->peer_buf_alloc = ptrans->peer_buf_alloc;
+	} else {
+		trans->buf_size = VIRTIO_VSOCK_DEFAULT_BUF_SIZE;
+		trans->buf_size_min = VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE;
+		trans->buf_size_max = VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE;
+	}
+
+	trans->buf_alloc = trans->buf_size;
+
+	pr_debug("%s: trans->buf_alloc=%d\n", __func__, trans->buf_alloc);
+
+	mutex_init(&trans->rx_lock);
+	mutex_init(&trans->tx_lock);
+	INIT_LIST_HEAD(&trans->rx_queue);
+	INIT_LIST_HEAD(&trans->incomplete_dgrams);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
+
+u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_buffer_size);
+
+u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size_min;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_min_buffer_size);
+
+u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size_max;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_max_buffer_size);
+
+void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+	if (val < trans->buf_size_min)
+		trans->buf_size_min = val;
+	if (val > trans->buf_size_max)
+		trans->buf_size_max = val;
+	trans->buf_size = val;
+	trans->buf_alloc = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_buffer_size);
+
+void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+	if (val > trans->buf_size)
+		trans->buf_size = val;
+	trans->buf_size_min = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_min_buffer_size);
+
+void virtio_transport_set_max_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+		val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+	if (val < trans->buf_size)
+		trans->buf_size = val;
+	trans->buf_size_max = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_max_buffer_size);
+
+int
+virtio_transport_notify_poll_in(struct vsock_sock *vsk,
+				size_t target,
+				bool *data_ready_now)
+{
+	if (vsock_stream_has_data(vsk))
+		*data_ready_now = true;
+	else
+		*data_ready_now = false;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
+
+int
+virtio_transport_notify_poll_out(struct vsock_sock *vsk,
+				 size_t target,
+				 bool *space_avail_now)
+{
+	s64 free_space;
+
+	free_space = vsock_stream_has_space(vsk);
+	if (free_space > 0)
+		*space_avail_now = true;
+	else if (free_space == 0)
+		*space_avail_now = false;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
+
+int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
+
+int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
+
+int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
+
+int virtio_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 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
+
+int virtio_transport_notify_send_init(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
+
+int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
+
+int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
+
+int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
+	ssize_t written, struct vsock_transport_send_notify_data *data)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
+
+u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	return trans->buf_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
+
+bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
+
+bool virtio_transport_stream_allow(u32 cid, u32 port)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
+
+int virtio_transport_dgram_bind(struct vsock_sock *vsk,
+				struct sockaddr_vm *addr)
+{
+	return vsock_bind_dgram_generic(vsk, addr);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
+
+bool virtio_transport_dgram_allow(u32 cid, u32 port)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
+
+int virtio_transport_connect(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_REQUEST,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+	};
+
+	pr_debug("%s: vsk=%p send_request\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_connect);
+
+int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_SHUTDOWN,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.flags = (mode & RCV_SHUTDOWN ?
+			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
+			 (mode & SEND_SHUTDOWN ?
+			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
+	};
+
+	pr_debug("%s: vsk=%p: send_shutdown\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
+
+void virtio_transport_release(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct sock *sk = &vsk->sk;
+	struct dgram_skb *dgram_skb;
+	struct dgram_skb *dgram_skb_tmp;
+
+	pr_debug("%s: vsk=%p\n", __func__, vsk);
+
+	/* Tell other side to terminate connection */
+	if (sk->sk_type == SOCK_STREAM && sk->sk_state == SS_CONNECTED) {
+		virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
+	}
+
+	/* Free incomplete dgrams */
+	lock_sock(sk);
+	list_for_each_entry_safe(dgram_skb, dgram_skb_tmp,
+				 &trans->incomplete_dgrams, list) {
+		list_del(&dgram_skb->list);
+		kfree_skb(dgram_skb->skb);
+		kfree(dgram_skb);
+		sock_put(sk); /* held in virtio_transport_recv_dgram() */
+	}
+	release_sock(sk);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_release);
+
+int
+virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+			       struct sockaddr_vm *remote_addr,
+			       struct msghdr *msg,
+			       size_t dgram_len)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RW,
+		.type = VIRTIO_VSOCK_TYPE_DGRAM,
+		.msg = msg,
+	};
+	size_t total_written = 0, pkt_off = 0, written;
+	u16 dgram_id;
+
+	/* The max size of a single dgram we support is 64KB */
+	if (dgram_len > VIRTIO_VSOCK_MAX_DGRAM_SIZE)
+		return -EMSGSIZE;
+
+	info.dgram_len = dgram_len;
+	vsk->remote_addr = *remote_addr;
+
+	dgram_id = trans->dgram_id++;
+
+	/* TODO: To optimize, if we have enough credit to send the pkt already,
+	 * do not ask the peer to send credit to use  */
+	virtio_transport_send_credit_request(vsk, VIRTIO_VSOCK_TYPE_DGRAM);
+
+	while (total_written < dgram_len) {
+		info.pkt_len = dgram_len - total_written;
+		info.flags = dgram_id << 16 | pkt_off;
+		written = trans->ops->send_pkt(vsk, &info);
+		if (written < 0)
+			return -ENOMEM;
+		if (written == 0) {
+			/* TODO: if written = 0, we need a sleep & wakeup
+			 * instead of sleep */
+			pr_debug("%s: SHOULD WAIT written==0", __func__);
+			msleep(10);
+		}
+		total_written += written;
+		pkt_off += written;
+		pr_debug("%s:id=%d, dgram_len=%zu, off=%zu, total_written=%zu, written=%zu\n",
+			  __func__, dgram_id, dgram_len, pkt_off, total_written, written);
+	}
+
+	return dgram_len;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
+
+ssize_t
+virtio_transport_stream_enqueue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RW,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.msg = msg,
+		.pkt_len = len,
+	};
+
+	return trans->ops->send_pkt(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
+
+void virtio_transport_destruct(struct vsock_sock *vsk)
+{
+	struct virtio_transport *trans = vsk->trans;
+
+	pr_debug("%s: vsk=%p\n", __func__, vsk);
+	kfree(trans);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_destruct);
+
+static int virtio_transport_send_ack(struct vsock_sock *vsk, u32 cookie)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_ACK,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.flags = cpu_to_le32(cookie),
+	};
+
+	pr_debug("%s: sk=%p send_offer\n", __func__, vsk);
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static int virtio_transport_send_reset(struct vsock_sock *vsk,
+				       struct virtio_vsock_pkt *pkt)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RST,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+	};
+
+	pr_debug("%s\n", __func__);
+
+	/* Send RST only if the original pkt is not a RST pkt */
+	if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
+		return 0;
+
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+static int
+virtio_transport_recv_connecting(struct sock *sk,
+				 struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	int err;
+	int skerr;
+	u32 cookie;
+
+	pr_debug("%s: vsk=%p\n", __func__, vsk);
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_RESPONSE:
+		cookie = le32_to_cpu(pkt->hdr.flags);
+		pr_debug("%s: got RESPONSE and send ACK, cookie=%x\n", __func__, cookie);
+		err = virtio_transport_send_ack(vsk, cookie);
+		if (err < 0) {
+			skerr = -err;
+			goto destroy;
+		}
+		sk->sk_state = SS_CONNECTED;
+		sk->sk_socket->state = SS_CONNECTED;
+		vsock_insert_connected(vsk);
+		sk->sk_state_change(sk);
+		break;
+	case VIRTIO_VSOCK_OP_INVALID:
+		pr_debug("%s: got invalid\n", __func__);
+		break;
+	case VIRTIO_VSOCK_OP_RST:
+		pr_debug("%s: got rst\n", __func__);
+		skerr = ECONNRESET;
+		err = 0;
+		goto destroy;
+	default:
+		pr_debug("%s: got def\n", __func__);
+		skerr = EPROTO;
+		err = -EINVAL;
+		goto destroy;
+	}
+	return 0;
+
+destroy:
+	virtio_transport_send_reset(vsk, pkt);
+	sk->sk_state = SS_UNCONNECTED;
+	sk->sk_err = skerr;
+	sk->sk_error_report(sk);
+	return err;
+}
+
+static int
+virtio_transport_recv_connected(struct sock *sk,
+				struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct virtio_transport *trans = vsk->trans;
+	int err = 0;
+
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_RW:
+		pkt->len = le32_to_cpu(pkt->hdr.len);
+		pkt->off = 0;
+		pkt->trans = trans;
+
+		mutex_lock(&trans->rx_lock);
+		virtio_transport_inc_rx_pkt(pkt);
+		list_add_tail(&pkt->list, &trans->rx_queue);
+		mutex_unlock(&trans->rx_lock);
+
+		sk->sk_data_ready(sk);
+		return err;
+	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
+		sk->sk_write_space(sk);
+		break;
+	case VIRTIO_VSOCK_OP_SHUTDOWN:
+		pr_debug("%s: got shutdown\n", __func__);
+		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
+			vsk->peer_shutdown |= RCV_SHUTDOWN;
+		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
+			vsk->peer_shutdown |= SEND_SHUTDOWN;
+		if (le32_to_cpu(pkt->hdr.flags))
+			sk->sk_state_change(sk);
+		break;
+	case VIRTIO_VSOCK_OP_RST:
+		pr_debug("%s: got rst\n", __func__);
+		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:
+		err = -EINVAL;
+		break;
+	}
+
+	virtio_transport_free_pkt(pkt);
+	return err;
+}
+
+static int
+virtio_transport_send_response(struct vsock_sock *vsk,
+			       struct virtio_vsock_pkt *pkt)
+{
+	struct virtio_transport *trans = vsk->trans;
+	struct virtio_vsock_pkt_info info = {
+		.op = VIRTIO_VSOCK_OP_RESPONSE,
+		.type = VIRTIO_VSOCK_TYPE_STREAM,
+		.remote_cid = le32_to_cpu(pkt->hdr.src_cid),
+		.remote_port = le32_to_cpu(pkt->hdr.src_port),
+	};
+	u32 cookie;
+
+	cookie = virtio_vsock_secure_cookie(le32_to_cpu(pkt->hdr.src_cid),
+					    le32_to_cpu(pkt->hdr.dst_cid),
+					    le32_to_cpu(pkt->hdr.src_port),
+					    le32_to_cpu(pkt->hdr.dst_port),
+					    jiffies / (HZ * 60));
+	info.flags = cpu_to_le32(cookie);
+
+	pr_debug("%s: send_response, cookie=%x\n", __func__, le32_to_cpu(cookie));
+
+	return trans->ops->send_pkt(vsk, &info);
+}
+
+/* Handle server socket */
+static int
+virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct vsock_sock *vpending;
+	struct sock *pending;
+	int err;
+	u32 cookie;
+
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_REQUEST:
+		err = virtio_transport_send_response(vsk, pkt);
+		if (err < 0) {
+			// FIXME vsk should be vpending
+			virtio_transport_send_reset(vsk, pkt);
+			return err;
+		}
+		break;
+	case VIRTIO_VSOCK_OP_ACK:
+		cookie = le32_to_cpu(pkt->hdr.flags);
+		err = virtio_vsock_check_cookie(le32_to_cpu(pkt->hdr.src_cid),
+						le32_to_cpu(pkt->hdr.dst_cid),
+						le32_to_cpu(pkt->hdr.src_port),
+						le32_to_cpu(pkt->hdr.dst_port),
+						jiffies / (HZ * 60),
+						le32_to_cpu(pkt->hdr.flags),
+						VSOCK_TIMEOUT_INIT);
+		pr_debug("%s: cookie=%x, err=%d\n", __func__, cookie, err);
+		if (err)
+			return err;
+
+		/* So no pending socket are responsible for this pkt, create one */
+		pr_debug("%s: create pending\n", __func__);
+		pending = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
+				sk->sk_type, 0);
+		if (!pending) {
+			virtio_transport_send_reset(vsk, pkt);
+			return -ENOMEM;
+		}
+		sk->sk_ack_backlog++;
+		pending->sk_state = SS_CONNECTING;
+
+		vpending = vsock_sk(pending);
+		vsock_addr_init(&vpending->local_addr, le32_to_cpu(pkt->hdr.dst_cid),
+				le32_to_cpu(pkt->hdr.dst_port));
+		vsock_addr_init(&vpending->remote_addr, le32_to_cpu(pkt->hdr.src_cid),
+				le32_to_cpu(pkt->hdr.src_port));
+		vsock_add_pending(sk, pending);
+
+		pr_debug("%s: get pending\n", __func__);
+		pending = virtio_transport_get_pending(sk, pkt);
+		vpending = vsock_sk(pending);
+		lock_sock(pending);
+		switch (pending->sk_state) {
+			case SS_CONNECTING:
+				if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_ACK) {
+					pr_debug("%s: op=%d != OP_ACK\n", __func__,
+						 le16_to_cpu(pkt->hdr.op));
+					virtio_transport_send_reset(vpending, pkt);
+					pending->sk_err = EPROTO;
+					pending->sk_state = SS_UNCONNECTED;
+					sock_put(pending);
+				} else {
+					pending->sk_state = SS_CONNECTED;
+					vsock_insert_connected(vpending);
+
+					vsock_remove_pending(sk, pending);
+					vsock_enqueue_accept(sk, pending);
+
+					sk->sk_data_ready(sk);
+				}
+				err = 0;
+				break;
+			default:
+				pr_debug("%s: sk->sk_ack_backlog=%d\n", __func__,
+						sk->sk_ack_backlog);
+				virtio_transport_send_reset(vpending, pkt);
+				err = -EINVAL;
+				break;
+		}
+		if (err < 0)
+			vsock_remove_pending(sk, pending);
+		release_sock(pending);
+
+		/* Release refcnt obtained in virtio_transport_get_pending */
+		sock_put(pending);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static void virtio_transport_space_update(struct sock *sk,
+					  struct virtio_vsock_pkt *pkt)
+{
+	struct vsock_sock *vsk = vsock_sk(sk);
+	struct virtio_transport *trans = vsk->trans;
+	bool space_available;
+
+	/* buf_alloc and fwd_cnt is always included in the hdr */
+	mutex_lock(&trans->tx_lock);
+	trans->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
+	trans->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
+	space_available = virtio_transport_has_space(vsk);
+	mutex_unlock(&trans->tx_lock);
+
+	if (space_available)
+		sk->sk_write_space(sk);
+}
+
+/* We are under the virtio-vsock's vsock->rx_lock or
+ * vhost-vsock's vq->mutex lock */
+void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
+{
+	struct virtio_transport *trans;
+	struct sockaddr_vm src, dst;
+	struct vsock_sock *vsk;
+	struct sock *sk;
+
+	vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid), le32_to_cpu(pkt->hdr.src_port));
+	vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid), le32_to_cpu(pkt->hdr.dst_port));
+
+	virtio_vsock_dumppkt(__func__, pkt);
+
+	if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_DGRAM) {
+		sk = vsock_find_unbound_socket(&dst);
+		if (!sk)
+			goto free_pkt;
+
+		vsk = vsock_sk(sk);
+		trans = vsk->trans;
+		BUG_ON(!trans);
+
+		virtio_transport_space_update(sk, pkt);
+
+		lock_sock(sk);
+		switch (le16_to_cpu(pkt->hdr.op)) {
+		case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
+			virtio_transport_free_pkt(pkt);
+			break;
+		case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
+			virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_DGRAM,
+							    &pkt->hdr);
+			virtio_transport_free_pkt(pkt);
+			break;
+		case VIRTIO_VSOCK_OP_RW:
+			virtio_transport_recv_dgram(sk, pkt);
+			break;
+		default:
+			virtio_transport_free_pkt(pkt);
+			break;
+		}
+		release_sock(sk);
+
+		/* Release refcnt obtained when we fetched this socket out of
+		 * the unbound list.
+		 */
+		sock_put(sk);
+		return;
+	} else if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM) {
+		/* The socket must be in connected or bound table
+		 * otherwise send reset back
+		 */
+		sk = vsock_find_connected_socket(&src, &dst);
+		if (!sk) {
+			sk = vsock_find_bound_socket(&dst);
+			if (!sk) {
+				pr_debug("%s: can not find bound_socket\n", __func__);
+				virtio_vsock_dumppkt(__func__, pkt);
+				/* Ignore this pkt instead of sending reset back */
+				/* TODO send a RST unless this packet is a RST (to avoid infinite loops) */
+				goto free_pkt;
+			}
+		}
+
+		vsk = vsock_sk(sk);
+		trans = vsk->trans;
+		BUG_ON(!trans);
+
+		virtio_transport_space_update(sk, pkt);
+
+		lock_sock(sk);
+		switch (sk->sk_state) {
+		case VSOCK_SS_LISTEN:
+			virtio_transport_recv_listen(sk, pkt);
+			virtio_transport_free_pkt(pkt);
+			break;
+		case SS_CONNECTING:
+			virtio_transport_recv_connecting(sk, pkt);
+			virtio_transport_free_pkt(pkt);
+			break;
+		case SS_CONNECTED:
+			virtio_transport_recv_connected(sk, pkt);
+			break;
+		default:
+			virtio_transport_free_pkt(pkt);
+			break;
+		}
+		release_sock(sk);
+
+		/* Release refcnt obtained when we fetched this socket out of the
+		 * bound or connected list.
+		 */
+		sock_put(sk);
+	}
+	return;
+
+free_pkt:
+	virtio_transport_free_pkt(pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
+
+void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
+{
+	kfree(pkt->buf);
+	kfree(pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
+
+static int __init virtio_vsock_common_init(void)
+{
+	get_random_bytes(vsockcookie_secret, sizeof(vsockcookie_secret));
+	return 0;
+}
+
+static void __exit virtio_vsock_common_exit(void)
+{
+}
+
+module_init(virtio_vsock_common_init);
+module_exit(virtio_vsock_common_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("common code for virtio vsock");