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Gerard Garciadavem330
Gerard Garcia
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davem330
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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 <[email protected]> Signed-off-by: Stefan Hajnoczi <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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‎MAINTAINERS‎

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@@ -13317,9 +13317,11 @@ L: [email protected]
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S: Maintained
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F: include/linux/virtio_vsock.h
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F: include/uapi/linux/virtio_vsock.h
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F: include/uapi/linux/vsockmon.h
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F: net/vmw_vsock/af_vsock_tap.c
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F: net/vmw_vsock/virtio_transport_common.c
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F: net/vmw_vsock/virtio_transport.c
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F: drivers/net/vsockmon.c
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F: drivers/vhost/vsock.c
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F: drivers/vhost/vsock.h
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‎drivers/net/Kconfig‎

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@@ -355,6 +355,14 @@ config NET_VRF
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This option enables the support for mapping interfaces into VRF's. The
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support enables VRF devices.
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config VSOCKMON
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tristate "Virtual vsock monitoring device"
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depends on VHOST_VSOCK
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---help---
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This option enables a monitoring net device for vsock sockets. It is
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mostly intended for developers or support to debug vsock issues. If
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unsure, say N.
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endif # NET_CORE
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config SUNGEM_PHY

‎drivers/net/Makefile‎

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@@ -30,6 +30,7 @@ obj-$(CONFIG_GENEVE) += geneve.o
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obj-$(CONFIG_GTP) += gtp.o
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obj-$(CONFIG_NLMON) += nlmon.o
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obj-$(CONFIG_NET_VRF) += vrf.o
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obj-$(CONFIG_VSOCKMON) += vsockmon.o
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#
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# Networking Drivers

‎drivers/net/vsockmon.c‎

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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/if_arp.h>
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#include <net/rtnetlink.h>
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#include <net/sock.h>
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#include <net/af_vsock.h>
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#include <uapi/linux/vsockmon.h>
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#include <linux/virtio_vsock.h>
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/* Virtio transport max packet size plus header */
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#define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
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sizeof(struct af_vsockmon_hdr))
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struct pcpu_lstats {
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u64 rx_packets;
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u64 rx_bytes;
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struct u64_stats_sync syncp;
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};
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static int vsockmon_dev_init(struct net_device *dev)
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{
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dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
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if (!dev->lstats)
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return -ENOMEM;
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return 0;
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}
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static void vsockmon_dev_uninit(struct net_device *dev)
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{
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free_percpu(dev->lstats);
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}
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struct vsockmon {
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struct vsock_tap vt;
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};
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static int vsockmon_open(struct net_device *dev)
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{
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struct vsockmon *vsockmon = netdev_priv(dev);
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vsockmon->vt.dev = dev;
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vsockmon->vt.module = THIS_MODULE;
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return vsock_add_tap(&vsockmon->vt);
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}
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static int vsockmon_close(struct net_device *dev)
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{
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struct vsockmon *vsockmon = netdev_priv(dev);
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return vsock_remove_tap(&vsockmon->vt);
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}
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static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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int len = skb->len;
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struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
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u64_stats_update_begin(&stats->syncp);
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stats->rx_bytes += len;
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stats->rx_packets++;
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u64_stats_update_end(&stats->syncp);
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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}
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static void
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vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
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{
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int i;
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u64 bytes = 0, packets = 0;
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for_each_possible_cpu(i) {
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const struct pcpu_lstats *vstats;
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u64 tbytes, tpackets;
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unsigned int start;
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vstats = per_cpu_ptr(dev->lstats, i);
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do {
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start = u64_stats_fetch_begin_irq(&vstats->syncp);
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tbytes = vstats->rx_bytes;
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tpackets = vstats->rx_packets;
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} while (u64_stats_fetch_retry_irq(&vstats->syncp, start));
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packets += tpackets;
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bytes += tbytes;
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}
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stats->rx_packets = packets;
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stats->tx_packets = 0;
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stats->rx_bytes = bytes;
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stats->tx_bytes = 0;
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}
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static int vsockmon_is_valid_mtu(int new_mtu)
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{
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return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
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}
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static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
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{
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if (!vsockmon_is_valid_mtu(new_mtu))
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return -EINVAL;
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dev->mtu = new_mtu;
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return 0;
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}
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static const struct net_device_ops vsockmon_ops = {
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.ndo_init = vsockmon_dev_init,
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.ndo_uninit = vsockmon_dev_uninit,
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.ndo_open = vsockmon_open,
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.ndo_stop = vsockmon_close,
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.ndo_start_xmit = vsockmon_xmit,
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.ndo_get_stats64 = vsockmon_get_stats64,
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.ndo_change_mtu = vsockmon_change_mtu,
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};
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static u32 always_on(struct net_device *dev)
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{
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return 1;
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}
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static const struct ethtool_ops vsockmon_ethtool_ops = {
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.get_link = always_on,
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};
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static void vsockmon_setup(struct net_device *dev)
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{
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dev->type = ARPHRD_VSOCKMON;
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dev->priv_flags |= IFF_NO_QUEUE;
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dev->netdev_ops = &vsockmon_ops;
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dev->ethtool_ops = &vsockmon_ethtool_ops;
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dev->destructor = free_netdev;
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dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
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NETIF_F_HIGHDMA | NETIF_F_LLTX;
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dev->flags = IFF_NOARP;
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dev->mtu = DEFAULT_MTU;
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}
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static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
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.kind = "vsockmon",
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.priv_size = sizeof(struct vsockmon),
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.setup = vsockmon_setup,
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};
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static __init int vsockmon_register(void)
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{
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return rtnl_link_register(&vsockmon_link_ops);
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}
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static __exit void vsockmon_unregister(void)
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{
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rtnl_link_unregister(&vsockmon_link_ops);
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}
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module_init(vsockmon_register);
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module_exit(vsockmon_unregister);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Gerard Garcia <[email protected]>");
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MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
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MODULE_ALIAS_RTNL_LINK("vsockmon");

‎include/uapi/linux/Kbuild‎

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@@ -477,6 +477,7 @@ header-y += virtio_types.h
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header-y += virtio_vsock.h
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header-y += virtio_crypto.h
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header-y += vm_sockets.h
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header-y += vsockmon.h
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header-y += vt.h
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header-y += vtpm_proxy.h
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header-y += wait.h

‎include/uapi/linux/vsockmon.h‎

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#ifndef _UAPI_VSOCKMON_H
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#define _UAPI_VSOCKMON_H
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#include <linux/virtio_vsock.h>
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/*
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* vsockmon is the AF_VSOCK packet capture device. Packets captured have the
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* following layout:
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*
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* +-----------------------------------+
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* | vsockmon header |
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* | (struct af_vsockmon_hdr) |
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* +-----------------------------------+
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* | transport header |
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* | (af_vsockmon_hdr->len bytes long) |
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* +-----------------------------------+
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* | payload |
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* | (until end of packet) |
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* +-----------------------------------+
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*
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* The vsockmon header is a transport-independent description of the packet.
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* It duplicates some of the information from the transport header so that
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* no transport-specific knowledge is necessary to process packets.
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*
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* The transport header is useful for low-level transport-specific packet
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* analysis. Transport type is given in af_vsockmon_hdr->transport and
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* transport header length is given in af_vsockmon_hdr->len.
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*
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* If af_vsockmon_hdr->op is AF_VSOCK_OP_PAYLOAD then the payload follows the
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* transport header. Other ops do not have a payload.
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*/
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struct af_vsockmon_hdr {
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__le64 src_cid;
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__le64 dst_cid;
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__le32 src_port;
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__le32 dst_port;
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__le16 op; /* enum af_vsockmon_op */
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__le16 transport; /* enum af_vsockmon_transport */
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__le16 len; /* Transport header length */
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__u8 reserved[2];
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};
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enum af_vsockmon_op {
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AF_VSOCK_OP_UNKNOWN = 0,
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AF_VSOCK_OP_CONNECT = 1,
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AF_VSOCK_OP_DISCONNECT = 2,
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AF_VSOCK_OP_CONTROL = 3,
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AF_VSOCK_OP_PAYLOAD = 4,
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};
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enum af_vsockmon_transport {
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AF_VSOCK_TRANSPORT_UNKNOWN = 0,
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AF_VSOCK_TRANSPORT_NO_INFO = 1, /* No transport information */
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/* Transport header type: struct virtio_vsock_hdr */
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AF_VSOCK_TRANSPORT_VIRTIO = 2,
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};
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#endif

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