From 531b374834c891ae2abf800693074df35a7d1a36 Mon Sep 17 00:00:00 2001
From: Gerard Garcia <ggarcia@deic.uab.cat>
Date: Fri, 21 Apr 2017 10:10:44 +0100
Subject: [PATCH 1/3] VSOCK: Add vsockmon tap functions

Add tap functions that can be used by the vsock transports to
deliver packets to vsockmon virtual network devices.

Signed-off-by: Gerard Garcia <ggarcia@deic.uab.cat>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 MAINTAINERS                  |   1 +
 include/net/af_vsock.h       |  13 ++++
 include/uapi/linux/if_arp.h  |   1 +
 net/vmw_vsock/Makefile       |   2 +-
 net/vmw_vsock/af_vsock_tap.c | 114 +++++++++++++++++++++++++++++++++++
 5 files changed, 130 insertions(+), 1 deletion(-)
 create mode 100644 net/vmw_vsock/af_vsock_tap.c

diff --git a/MAINTAINERS b/MAINTAINERS
index b283d5ef7b68..fdab4f9e8ac9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13317,6 +13317,7 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	include/linux/virtio_vsock.h
 F:	include/uapi/linux/virtio_vsock.h
+F:	net/vmw_vsock/af_vsock_tap.c
 F:	net/vmw_vsock/virtio_transport_common.c
 F:	net/vmw_vsock/virtio_transport.c
 F:	drivers/vhost/vsock.c
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index f32ed9ac181a..f9fb566e75cf 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -188,4 +188,17 @@ struct sock *vsock_find_connected_socket(struct sockaddr_vm *src,
 void vsock_remove_sock(struct vsock_sock *vsk);
 void vsock_for_each_connected_socket(void (*fn)(struct sock *sk));
 
+/**** TAP ****/
+
+struct vsock_tap {
+	struct net_device *dev;
+	struct module *module;
+	struct list_head list;
+};
+
+int vsock_init_tap(void);
+int vsock_add_tap(struct vsock_tap *vt);
+int vsock_remove_tap(struct vsock_tap *vt);
+void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque);
+
 #endif /* __AF_VSOCK_H__ */
diff --git a/include/uapi/linux/if_arp.h b/include/uapi/linux/if_arp.h
index 4d024d75d64b..cf73510b9238 100644
--- a/include/uapi/linux/if_arp.h
+++ b/include/uapi/linux/if_arp.h
@@ -95,6 +95,7 @@
 #define ARPHRD_IP6GRE	823		/* GRE over IPv6		*/
 #define ARPHRD_NETLINK	824		/* Netlink header		*/
 #define ARPHRD_6LOWPAN	825		/* IPv6 over LoWPAN             */
+#define ARPHRD_VSOCKMON	826		/* Vsock monitor header		*/
 
 #define ARPHRD_VOID	  0xFFFF	/* Void type, nothing is known */
 #define ARPHRD_NONE	  0xFFFE	/* zero header length */
diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
index bc27c70e0e59..09fc2eb29dc8 100644
--- a/net/vmw_vsock/Makefile
+++ b/net/vmw_vsock/Makefile
@@ -3,7 +3,7 @@ obj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o
 obj-$(CONFIG_VIRTIO_VSOCKETS) += vmw_vsock_virtio_transport.o
 obj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += vmw_vsock_virtio_transport_common.o
 
-vsock-y += af_vsock.o vsock_addr.o
+vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o
 
 vmw_vsock_vmci_transport-y += vmci_transport.o vmci_transport_notify.o \
 	vmci_transport_notify_qstate.o
diff --git a/net/vmw_vsock/af_vsock_tap.c b/net/vmw_vsock/af_vsock_tap.c
new file mode 100644
index 000000000000..98f09b539366
--- /dev/null
+++ b/net/vmw_vsock/af_vsock_tap.c
@@ -0,0 +1,114 @@
+/*
+ * Tap functions for AF_VSOCK sockets.
+ *
+ * Code based on net/netlink/af_netlink.c tap functions.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <net/sock.h>
+#include <net/af_vsock.h>
+#include <linux/if_arp.h>
+
+static DEFINE_SPINLOCK(vsock_tap_lock);
+static struct list_head vsock_tap_all __read_mostly =
+				LIST_HEAD_INIT(vsock_tap_all);
+
+int vsock_add_tap(struct vsock_tap *vt)
+{
+	if (unlikely(vt->dev->type != ARPHRD_VSOCKMON))
+		return -EINVAL;
+
+	__module_get(vt->module);
+
+	spin_lock(&vsock_tap_lock);
+	list_add_rcu(&vt->list, &vsock_tap_all);
+	spin_unlock(&vsock_tap_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vsock_add_tap);
+
+int vsock_remove_tap(struct vsock_tap *vt)
+{
+	struct vsock_tap *tmp;
+	bool found = false;
+
+	spin_lock(&vsock_tap_lock);
+
+	list_for_each_entry(tmp, &vsock_tap_all, list) {
+		if (vt == tmp) {
+			list_del_rcu(&vt->list);
+			found = true;
+			goto out;
+		}
+	}
+
+	pr_warn("vsock_remove_tap: %p not found\n", vt);
+out:
+	spin_unlock(&vsock_tap_lock);
+
+	synchronize_net();
+
+	if (found)
+		module_put(vt->module);
+
+	return found ? 0 : -ENODEV;
+}
+EXPORT_SYMBOL_GPL(vsock_remove_tap);
+
+static int __vsock_deliver_tap_skb(struct sk_buff *skb,
+				   struct net_device *dev)
+{
+	int ret = 0;
+	struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
+
+	if (nskb) {
+		dev_hold(dev);
+
+		nskb->dev = dev;
+		ret = dev_queue_xmit(nskb);
+		if (unlikely(ret > 0))
+			ret = net_xmit_errno(ret);
+
+		dev_put(dev);
+	}
+
+	return ret;
+}
+
+static void __vsock_deliver_tap(struct sk_buff *skb)
+{
+	int ret;
+	struct vsock_tap *tmp;
+
+	list_for_each_entry_rcu(tmp, &vsock_tap_all, list) {
+		ret = __vsock_deliver_tap_skb(skb, tmp->dev);
+		if (unlikely(ret))
+			break;
+	}
+}
+
+void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque)
+{
+	struct sk_buff *skb;
+
+	rcu_read_lock();
+
+	if (likely(list_empty(&vsock_tap_all)))
+		goto out;
+
+	skb = build_skb(opaque);
+	if (skb) {
+		__vsock_deliver_tap(skb);
+		consume_skb(skb);
+	}
+
+out:
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(vsock_deliver_tap);

From 0b2e66448ba20eb30ea62345d6beb9ee2a1ce06b Mon Sep 17 00:00:00 2001
From: Gerard Garcia <ggarcia@deic.uab.cat>
Date: Fri, 21 Apr 2017 10:10:45 +0100
Subject: [PATCH 2/3] VSOCK: Add vsockmon device

Add vsockmon virtual network device that receives packets from the vsock
transports and exposes them to user space.

Based on the nlmon device.

Signed-off-by: Gerard Garcia <ggarcia@deic.uab.cat>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 MAINTAINERS                   |   2 +
 drivers/net/Kconfig           |   8 ++
 drivers/net/Makefile          |   1 +
 drivers/net/vsockmon.c        | 170 ++++++++++++++++++++++++++++++++++
 include/uapi/linux/Kbuild     |   1 +
 include/uapi/linux/vsockmon.h |  60 ++++++++++++
 6 files changed, 242 insertions(+)
 create mode 100644 drivers/net/vsockmon.c
 create mode 100644 include/uapi/linux/vsockmon.h

diff --git a/MAINTAINERS b/MAINTAINERS
index fdab4f9e8ac9..28ea78b12d0c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13317,9 +13317,11 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	include/linux/virtio_vsock.h
 F:	include/uapi/linux/virtio_vsock.h
+F:	include/uapi/linux/vsockmon.h
 F:	net/vmw_vsock/af_vsock_tap.c
 F:	net/vmw_vsock/virtio_transport_common.c
 F:	net/vmw_vsock/virtio_transport.c
+F:	drivers/net/vsockmon.c
 F:	drivers/vhost/vsock.c
 F:	drivers/vhost/vsock.h
 
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 100fbdc9b95c..83a1616903f8 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -355,6 +355,14 @@ config NET_VRF
 	  This option enables the support for mapping interfaces into VRF's. The
 	  support enables VRF devices.
 
+config VSOCKMON
+    tristate "Virtual vsock monitoring device"
+    depends on VHOST_VSOCK
+    ---help---
+     This option enables a monitoring net device for vsock sockets. It is
+     mostly intended for developers or support to debug vsock issues. If
+     unsure, say N.
+
 endif # NET_CORE
 
 config SUNGEM_PHY
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 57fc47ad5ab3..b2f6556d8848 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_GENEVE) += geneve.o
 obj-$(CONFIG_GTP) += gtp.o
 obj-$(CONFIG_NLMON) += nlmon.o
 obj-$(CONFIG_NET_VRF) += vrf.o
+obj-$(CONFIG_VSOCKMON) += vsockmon.o
 
 #
 # Networking Drivers
diff --git a/drivers/net/vsockmon.c b/drivers/net/vsockmon.c
new file mode 100644
index 000000000000..7f0136f2dd9d
--- /dev/null
+++ b/drivers/net/vsockmon.c
@@ -0,0 +1,170 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/if_arp.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+#include <net/af_vsock.h>
+#include <uapi/linux/vsockmon.h>
+#include <linux/virtio_vsock.h>
+
+/* Virtio transport max packet size plus header */
+#define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
+		     sizeof(struct af_vsockmon_hdr))
+
+struct pcpu_lstats {
+	u64 rx_packets;
+	u64 rx_bytes;
+	struct u64_stats_sync syncp;
+};
+
+static int vsockmon_dev_init(struct net_device *dev)
+{
+	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
+	if (!dev->lstats)
+		return -ENOMEM;
+	return 0;
+}
+
+static void vsockmon_dev_uninit(struct net_device *dev)
+{
+	free_percpu(dev->lstats);
+}
+
+struct vsockmon {
+	struct vsock_tap vt;
+};
+
+static int vsockmon_open(struct net_device *dev)
+{
+	struct vsockmon *vsockmon = netdev_priv(dev);
+
+	vsockmon->vt.dev = dev;
+	vsockmon->vt.module = THIS_MODULE;
+	return vsock_add_tap(&vsockmon->vt);
+}
+
+static int vsockmon_close(struct net_device *dev)
+{
+	struct vsockmon *vsockmon = netdev_priv(dev);
+
+	return vsock_remove_tap(&vsockmon->vt);
+}
+
+static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	int len = skb->len;
+	struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
+
+	u64_stats_update_begin(&stats->syncp);
+	stats->rx_bytes += len;
+	stats->rx_packets++;
+	u64_stats_update_end(&stats->syncp);
+
+	dev_kfree_skb(skb);
+
+	return NETDEV_TX_OK;
+}
+
+static void
+vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
+{
+	int i;
+	u64 bytes = 0, packets = 0;
+
+	for_each_possible_cpu(i) {
+		const struct pcpu_lstats *vstats;
+		u64 tbytes, tpackets;
+		unsigned int start;
+
+		vstats = per_cpu_ptr(dev->lstats, i);
+
+		do {
+			start = u64_stats_fetch_begin_irq(&vstats->syncp);
+			tbytes = vstats->rx_bytes;
+			tpackets = vstats->rx_packets;
+		} while (u64_stats_fetch_retry_irq(&vstats->syncp, start));
+
+		packets += tpackets;
+		bytes += tbytes;
+	}
+
+	stats->rx_packets = packets;
+	stats->tx_packets = 0;
+
+	stats->rx_bytes = bytes;
+	stats->tx_bytes = 0;
+}
+
+static int vsockmon_is_valid_mtu(int new_mtu)
+{
+	return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
+}
+
+static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (!vsockmon_is_valid_mtu(new_mtu))
+		return -EINVAL;
+
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops vsockmon_ops = {
+	.ndo_init = vsockmon_dev_init,
+	.ndo_uninit = vsockmon_dev_uninit,
+	.ndo_open = vsockmon_open,
+	.ndo_stop = vsockmon_close,
+	.ndo_start_xmit = vsockmon_xmit,
+	.ndo_get_stats64 = vsockmon_get_stats64,
+	.ndo_change_mtu = vsockmon_change_mtu,
+};
+
+static u32 always_on(struct net_device *dev)
+{
+	return 1;
+}
+
+static const struct ethtool_ops vsockmon_ethtool_ops = {
+	.get_link = always_on,
+};
+
+static void vsockmon_setup(struct net_device *dev)
+{
+	dev->type = ARPHRD_VSOCKMON;
+	dev->priv_flags |= IFF_NO_QUEUE;
+
+	dev->netdev_ops	= &vsockmon_ops;
+	dev->ethtool_ops = &vsockmon_ethtool_ops;
+	dev->destructor	= free_netdev;
+
+	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
+			NETIF_F_HIGHDMA | NETIF_F_LLTX;
+
+	dev->flags = IFF_NOARP;
+
+	dev->mtu = DEFAULT_MTU;
+}
+
+static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
+	.kind			= "vsockmon",
+	.priv_size		= sizeof(struct vsockmon),
+	.setup			= vsockmon_setup,
+};
+
+static __init int vsockmon_register(void)
+{
+	return rtnl_link_register(&vsockmon_link_ops);
+}
+
+static __exit void vsockmon_unregister(void)
+{
+	rtnl_link_unregister(&vsockmon_link_ops);
+}
+
+module_init(vsockmon_register);
+module_exit(vsockmon_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
+MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
+MODULE_ALIAS_RTNL_LINK("vsockmon");
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index f8d9fed17ba9..6b0e2758585f 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -477,6 +477,7 @@ header-y += virtio_types.h
 header-y += virtio_vsock.h
 header-y += virtio_crypto.h
 header-y += vm_sockets.h
+header-y += vsockmon.h
 header-y += vt.h
 header-y += vtpm_proxy.h
 header-y += wait.h
diff --git a/include/uapi/linux/vsockmon.h b/include/uapi/linux/vsockmon.h
new file mode 100644
index 000000000000..a08b522ef597
--- /dev/null
+++ b/include/uapi/linux/vsockmon.h
@@ -0,0 +1,60 @@
+#ifndef _UAPI_VSOCKMON_H
+#define _UAPI_VSOCKMON_H
+
+#include <linux/virtio_vsock.h>
+
+/*
+ * vsockmon is the AF_VSOCK packet capture device.  Packets captured have the
+ * following layout:
+ *
+ *   +-----------------------------------+
+ *   |           vsockmon header         |
+ *   |      (struct af_vsockmon_hdr)     |
+ *   +-----------------------------------+
+ *   |          transport header         |
+ *   | (af_vsockmon_hdr->len bytes long) |
+ *   +-----------------------------------+
+ *   |              payload              |
+ *   |       (until end of packet)       |
+ *   +-----------------------------------+
+ *
+ * The vsockmon header is a transport-independent description of the packet.
+ * It duplicates some of the information from the transport header so that
+ * no transport-specific knowledge is necessary to process packets.
+ *
+ * The transport header is useful for low-level transport-specific packet
+ * analysis.  Transport type is given in af_vsockmon_hdr->transport and
+ * transport header length is given in af_vsockmon_hdr->len.
+ *
+ * If af_vsockmon_hdr->op is AF_VSOCK_OP_PAYLOAD then the payload follows the
+ * transport header.  Other ops do not have a payload.
+ */
+
+struct af_vsockmon_hdr {
+	__le64 src_cid;
+	__le64 dst_cid;
+	__le32 src_port;
+	__le32 dst_port;
+	__le16 op;			/* enum af_vsockmon_op */
+	__le16 transport;		/* enum af_vsockmon_transport */
+	__le16 len;			/* Transport header length */
+	__u8 reserved[2];
+};
+
+enum af_vsockmon_op {
+	AF_VSOCK_OP_UNKNOWN = 0,
+	AF_VSOCK_OP_CONNECT = 1,
+	AF_VSOCK_OP_DISCONNECT = 2,
+	AF_VSOCK_OP_CONTROL = 3,
+	AF_VSOCK_OP_PAYLOAD = 4,
+};
+
+enum af_vsockmon_transport {
+	AF_VSOCK_TRANSPORT_UNKNOWN = 0,
+	AF_VSOCK_TRANSPORT_NO_INFO = 1,	/* No transport information */
+
+	/* Transport header type: struct virtio_vsock_hdr */
+	AF_VSOCK_TRANSPORT_VIRTIO = 2,
+};
+
+#endif

From 82dfb540aeb277d945bf646ff780493b8a520d8a Mon Sep 17 00:00:00 2001
From: Gerard Garcia <ggarcia@deic.uab.cat>
Date: Fri, 21 Apr 2017 10:10:46 +0100
Subject: [PATCH 3/3] VSOCK: Add virtio vsock vsockmon hooks

The virtio drivers deal with struct virtio_vsock_pkt.  Add
virtio_transport_deliver_tap_pkt(pkt) for handing packets to the
vsockmon device.

We call virtio_transport_deliver_tap_pkt(pkt) from
net/vmw_vsock/virtio_transport.c and drivers/vhost/vsock.c instead of
common code.  This is because the drivers may drop packets before
handing them to common code - we still want to capture them.

Signed-off-by: Gerard Garcia <ggarcia@deic.uab.cat>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/vhost/vsock.c                   |  8 ++++
 include/linux/virtio_vsock.h            |  1 +
 net/vmw_vsock/virtio_transport.c        |  3 ++
 net/vmw_vsock/virtio_transport_common.c | 64 +++++++++++++++++++++++++
 4 files changed, 76 insertions(+)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 44eed8eb0725..d939ac1a4997 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -176,6 +176,11 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 				restart_tx = true;
 		}
 
+		/* Deliver to monitoring devices all correctly transmitted
+		 * packets.
+		 */
+		virtio_transport_deliver_tap_pkt(pkt);
+
 		virtio_transport_free_pkt(pkt);
 	}
 	if (added)
@@ -383,6 +388,9 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 
 		len = pkt->len;
 
+		/* Deliver to monitoring devices all received packets */
+		virtio_transport_deliver_tap_pkt(pkt);
+
 		/* Only accept correctly addressed packets */
 		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid)
 			virtio_transport_recv_pkt(pkt);
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 584f9a647ad4..ab13f0743da8 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -153,5 +153,6 @@ void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt);
 void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt);
 u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 wanted);
 void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
+void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt);
 
 #endif /* _LINUX_VIRTIO_VSOCK_H */
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 68675a151f22..9dffe0282ad4 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -144,6 +144,8 @@ virtio_transport_send_pkt_work(struct work_struct *work)
 		list_del_init(&pkt->list);
 		spin_unlock_bh(&vsock->send_pkt_list_lock);
 
+		virtio_transport_deliver_tap_pkt(pkt);
+
 		reply = pkt->reply;
 
 		sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
@@ -370,6 +372,7 @@ static void virtio_transport_rx_work(struct work_struct *work)
 			}
 
 			pkt->len = len - sizeof(pkt->hdr);
+			virtio_transport_deliver_tap_pkt(pkt);
 			virtio_transport_recv_pkt(pkt);
 		}
 	} while (!virtqueue_enable_cb(vq));
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index af087b44ceea..18e24793659f 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -16,6 +16,7 @@
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
 #include <linux/virtio_vsock.h>
+#include <uapi/linux/vsockmon.h>
 
 #include <net/sock.h>
 #include <net/af_vsock.h>
@@ -85,6 +86,69 @@ out_pkt:
 	return NULL;
 }
 
+/* Packet capture */
+static struct sk_buff *virtio_transport_build_skb(void *opaque)
+{
+	struct virtio_vsock_pkt *pkt = opaque;
+	unsigned char *t_hdr, *payload;
+	struct af_vsockmon_hdr *hdr;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + pkt->len,
+			GFP_ATOMIC);
+	if (!skb)
+		return NULL;
+
+	hdr = (struct af_vsockmon_hdr *)skb_put(skb, sizeof(*hdr));
+
+	/* pkt->hdr is little-endian so no need to byteswap here */
+	hdr->src_cid = pkt->hdr.src_cid;
+	hdr->src_port = pkt->hdr.src_port;
+	hdr->dst_cid = pkt->hdr.dst_cid;
+	hdr->dst_port = pkt->hdr.dst_port;
+
+	hdr->transport = cpu_to_le16(AF_VSOCK_TRANSPORT_VIRTIO);
+	hdr->len = cpu_to_le16(sizeof(pkt->hdr));
+	memset(hdr->reserved, 0, sizeof(hdr->reserved));
+
+	switch (le16_to_cpu(pkt->hdr.op)) {
+	case VIRTIO_VSOCK_OP_REQUEST:
+	case VIRTIO_VSOCK_OP_RESPONSE:
+		hdr->op = cpu_to_le16(AF_VSOCK_OP_CONNECT);
+		break;
+	case VIRTIO_VSOCK_OP_RST:
+	case VIRTIO_VSOCK_OP_SHUTDOWN:
+		hdr->op = cpu_to_le16(AF_VSOCK_OP_DISCONNECT);
+		break;
+	case VIRTIO_VSOCK_OP_RW:
+		hdr->op = cpu_to_le16(AF_VSOCK_OP_PAYLOAD);
+		break;
+	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
+	case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
+		hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
+		break;
+	default:
+		hdr->op = cpu_to_le16(AF_VSOCK_OP_UNKNOWN);
+		break;
+	}
+
+	t_hdr = skb_put(skb, sizeof(pkt->hdr));
+	memcpy(t_hdr, &pkt->hdr, sizeof(pkt->hdr));
+
+	if (pkt->len) {
+		payload = skb_put(skb, pkt->len);
+		memcpy(payload, pkt->buf, pkt->len);
+	}
+
+	return skb;
+}
+
+void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
+{
+	vsock_deliver_tap(virtio_transport_build_skb, pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
+
 static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
 					  struct virtio_vsock_pkt_info *info)
 {