// SPDX-License-Identifier: GPL-2.0-only#include <linux/ethtool.h>#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 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){	dev_lstats_add(dev, skb->len); 	dev_kfree_skb(skb); 	return NETDEV_TX_OK;} static voidvsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats){	dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);} 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; 	WRITE_ONCE(dev->mtu, new_mtu);	return 0;} static const struct net_device_ops vsockmon_ops = {	.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->lltx = true; 	dev->netdev_ops	= &vsockmon_ops;	dev->ethtool_ops = &vsockmon_ethtool_ops;	dev->needs_free_netdev = true; 	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA; 	dev->flags = IFF_NOARP; 	dev->mtu = DEFAULT_MTU;	dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;} 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");