VSOCK: Introduce virtio-vsock-common.ko

This module contains the common code and header files for the following
virtio-vsock and virtio-vhost kernel modules.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/virtio_vsock.h

+/*
+ * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers:
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright (C) Red Hat, Inc., 2013-2015
+ * Copyright (C) Asias He <asias@redhat.com>, 2013
+ * Copyright (C) Stefan Hajnoczi <stefanha@redhat.com>, 2015
+ */
+
+#ifndef _LINUX_VIRTIO_VSOCK_H
+#define _LINUX_VIRTIO_VSOCK_H
+
+#include <uapi/linux/virtio_vsock.h>
+#include <linux/socket.h>
+#include <net/sock.h>
+
+#define VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE	128
+#define VIRTIO_VSOCK_DEFAULT_BUF_SIZE		(1024 * 256)
+#define VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE	(1024 * 256)
+#define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 4)
+#define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
+#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
+#define VIRTIO_VSOCK_MAX_TX_BUF_SIZE		(1024 * 1024 * 16)
+#define VIRTIO_VSOCK_MAX_DGRAM_SIZE		(1024 * 64)
+
+struct vsock_transport_recv_notify_data;
+struct vsock_transport_send_notify_data;
+struct sockaddr_vm;
+struct vsock_sock;
+
+enum {
+	VSOCK_VQ_CTRL	= 0,
+	VSOCK_VQ_RX	= 1, /* for host to guest data */
+	VSOCK_VQ_TX	= 2, /* for guest to host data */
+	VSOCK_VQ_MAX	= 3,
+};
+
+/* virtio transport socket state */
+struct virtio_transport {
+	struct virtio_transport_pkt_ops	*ops;
+	struct vsock_sock *vsk;
+
+	u32 buf_size;
+	u32 buf_size_min;
+	u32 buf_size_max;
+
+	struct mutex tx_lock;
+	struct mutex rx_lock;
+
+	struct list_head rx_queue;
+	u32 rx_bytes;
+
+	/* Protected by trans->tx_lock */
+	u32 tx_cnt;
+	u32 buf_alloc;
+	u32 peer_fwd_cnt;
+	u32 peer_buf_alloc;
+	/* Protected by trans->rx_lock */
+	u32 fwd_cnt;
+
+	/* Protected by sk_lock */
+	u16 dgram_id;
+	struct list_head incomplete_dgrams; /* dgram fragments */
+};
+
+struct virtio_vsock_pkt {
+	struct virtio_vsock_hdr	hdr;
+	struct virtio_transport	*trans;
+	struct work_struct work;
+	struct list_head list;
+	void *buf;
+	u32 len;
+	u32 off;
+};
+
+struct virtio_vsock_pkt_info {
+	u32 remote_cid, remote_port;
+	struct msghdr *msg;
+	u32 pkt_len;
+	u16 type;
+	u16 op;
+	u32 flags;
+	u16 dgram_id;
+	u16 dgram_len;
+};
+
+struct virtio_transport_pkt_ops {
+	int (*send_pkt)(struct vsock_sock *vsk,
+			struct virtio_vsock_pkt_info *info);
+};
+
+void virtio_vsock_dumppkt(const char *func,
+			  const struct virtio_vsock_pkt *pkt);
+
+struct sock *
+virtio_transport_get_pending(struct sock *listener,
+			     struct virtio_vsock_pkt *pkt);
+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);
+ssize_t
+virtio_transport_stream_dequeue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len,
+				int type);
+int
+virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
+			       struct msghdr *msg,
+			       size_t len, int flags);
+
+s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
+s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
+
+int virtio_transport_do_socket_init(struct vsock_sock *vsk,
+				 struct vsock_sock *psk);
+u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk);
+u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk);
+u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk);
+void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val);
+void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val);
+void virtio_transport_set_max_buffer_size(struct vsock_sock *vs, u64 val);
+int
+virtio_transport_notify_poll_in(struct vsock_sock *vsk,
+				size_t target,
+				bool *data_ready_now);
+int
+virtio_transport_notify_poll_out(struct vsock_sock *vsk,
+				 size_t target,
+				 bool *space_available_now);
+
+int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data);
+int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data);
+int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
+	size_t target, struct vsock_transport_recv_notify_data *data);
+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);
+int virtio_transport_notify_send_init(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data);
+int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data);
+int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
+	struct vsock_transport_send_notify_data *data);
+int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
+	ssize_t written, struct vsock_transport_send_notify_data *data);
+
+u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk);
+bool virtio_transport_stream_is_active(struct vsock_sock *vsk);
+bool virtio_transport_stream_allow(u32 cid, u32 port);
+int virtio_transport_dgram_bind(struct vsock_sock *vsk,
+				struct sockaddr_vm *addr);
+bool virtio_transport_dgram_allow(u32 cid, u32 port);
+
+int virtio_transport_connect(struct vsock_sock *vsk);
+
+int virtio_transport_shutdown(struct vsock_sock *vsk, int mode);
+
+void virtio_transport_release(struct vsock_sock *vsk);
+
+ssize_t
+virtio_transport_stream_enqueue(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len);
+int
+virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+			       struct sockaddr_vm *remote_addr,
+			       struct msghdr *msg,
+			       size_t len);
+
+void virtio_transport_destruct(struct vsock_sock *vsk);
+
+void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_inc_tx_pkt(struct virtio_vsock_pkt *pkt);
+void virtio_transport_dec_tx_pkt(struct virtio_vsock_pkt *pkt);
+u32 virtio_transport_get_credit(struct virtio_transport *trans, u32 wanted);
+void virtio_transport_put_credit(struct virtio_transport *trans, u32 credit);
+#endif /* _LINUX_VIRTIO_VSOCK_H */

include/uapi/linux/virtio_ids.h

@@ -39,6 +39,7 @@
 #define VIRTIO_ID_9P		9 /* 9p virtio console */
 #define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */
 #define VIRTIO_ID_CAIF	       12 /* Virtio caif */
+#define VIRTIO_ID_VSOCK        13 /* virtio vsock transport */
 #define VIRTIO_ID_GPU          16 /* virtio GPU */
 #define VIRTIO_ID_INPUT        18 /* virtio input */
 

include/uapi/linux/virtio_vsock.h

+/*
+ * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers:
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright (C) Red Hat, Inc., 2013-2015
+ * Copyright (C) Asias He <asias@redhat.com>, 2013
+ * Copyright (C) Stefan Hajnoczi <stefanha@redhat.com>, 2015
+ */
+
+#ifndef _UAPI_LINUX_VIRTIO_VSOCK_H
+#define _UAPI_LINUX_VIRTIO_VOSCK_H
+
+#include <linux/types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+
+struct virtio_vsock_config {
+	__le32 guest_cid;
+	__le32 max_virtqueue_pairs;
+};
+
+struct virtio_vsock_hdr {
+	__le32	src_cid;
+	__le32	src_port;
+	__le32	dst_cid;
+	__le32	dst_port;
+	__le32	len;
+	__le16	type;		/* enum virtio_vsock_type */
+	__le16	op;		/* enum virtio_vsock_op */
+	__le32	flags;
+	__le32	buf_alloc;
+	__le32	fwd_cnt;
+};
+
+enum virtio_vsock_type {
+	VIRTIO_VSOCK_TYPE_STREAM = 1,
+	VIRTIO_VSOCK_TYPE_DGRAM = 2,
+};
+
+enum virtio_vsock_op {
+	VIRTIO_VSOCK_OP_INVALID = 0,
+
+	/* Connect operations */
+	VIRTIO_VSOCK_OP_REQUEST = 1,
+	VIRTIO_VSOCK_OP_RESPONSE = 2,
+	VIRTIO_VSOCK_OP_ACK = 3,
+	VIRTIO_VSOCK_OP_RST = 4,
+	VIRTIO_VSOCK_OP_SHUTDOWN = 5,
+
+	/* To send payload */
+	VIRTIO_VSOCK_OP_RW = 6,
+
+	/* Tell the peer our credit info */
+	VIRTIO_VSOCK_OP_CREDIT_UPDATE = 7,
+	/* Request the peer to send the credit info to us */
+	VIRTIO_VSOCK_OP_CREDIT_REQUEST = 8,
+};
+
+/* VIRTIO_VSOCK_OP_SHUTDOWN flags values */
+enum virtio_vsock_shutdown {
+	VIRTIO_VSOCK_SHUTDOWN_RCV = 1,
+	VIRTIO_VSOCK_SHUTDOWN_SEND = 2,
+};
+
+#endif /* _UAPI_LINUX_VIRTIO_VSOCK_H */

net/vmw_vsock/virtio_transport_common.c

+/*
+ * 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");