1// SPDX-License-Identifier: GPL-2.0-only
  2#include <linux/ethtool.h>
  3#include <linux/module.h>
  4#include <linux/kernel.h>
  5#include <linux/if_arp.h>
  6#include <net/rtnetlink.h>
  7#include <net/sock.h>
  8#include <net/af_vsock.h>
  9#include <uapi/linux/vsockmon.h>
 10#include <linux/virtio_vsock.h>
 11
 12/* Virtio transport max packet size plus header */
 13#define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
 14		     sizeof(struct af_vsockmon_hdr))
 15
 16struct vsockmon {
 17	struct vsock_tap vt;
 18};
 19
 20static int vsockmon_open(struct net_device *dev)
 21{
 22	struct vsockmon *vsockmon = netdev_priv(dev);
 23
 24	vsockmon->vt.dev = dev;
 25	vsockmon->vt.module = THIS_MODULE;
 26	return vsock_add_tap(&vsockmon->vt);
 27}
 28
 29static int vsockmon_close(struct net_device *dev)
 30{
 31	struct vsockmon *vsockmon = netdev_priv(dev);
 32
 33	return vsock_remove_tap(&vsockmon->vt);
 34}
 35
 36static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
 37{
 38	dev_lstats_add(dev, skb->len);
 39
 40	dev_kfree_skb(skb);
 41
 42	return NETDEV_TX_OK;
 43}
 44
 45static void
 46vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 47{
 48	dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
 49}
 50
 51static int vsockmon_is_valid_mtu(int new_mtu)
 52{
 53	return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
 54}
 55
 56static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
 57{
 58	if (!vsockmon_is_valid_mtu(new_mtu))
 59		return -EINVAL;
 60
 61	dev->mtu = new_mtu;
 62	return 0;
 63}
 64
 65static const struct net_device_ops vsockmon_ops = {
 66	.ndo_open = vsockmon_open,
 67	.ndo_stop = vsockmon_close,
 68	.ndo_start_xmit = vsockmon_xmit,
 69	.ndo_get_stats64 = vsockmon_get_stats64,
 70	.ndo_change_mtu = vsockmon_change_mtu,
 71};
 72
 73static u32 always_on(struct net_device *dev)
 74{
 75	return 1;
 76}
 77
 78static const struct ethtool_ops vsockmon_ethtool_ops = {
 79	.get_link = always_on,
 80};
 81
 82static void vsockmon_setup(struct net_device *dev)
 83{
 84	dev->type = ARPHRD_VSOCKMON;
 85	dev->priv_flags |= IFF_NO_QUEUE;
 86
 87	dev->netdev_ops	= &vsockmon_ops;
 88	dev->ethtool_ops = &vsockmon_ethtool_ops;
 89	dev->needs_free_netdev = true;
 90
 91	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
 92			NETIF_F_HIGHDMA | NETIF_F_LLTX;
 93
 94	dev->flags = IFF_NOARP;
 95
 96	dev->mtu = DEFAULT_MTU;
 97	dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
 98}
 99
100static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
101	.kind			= "vsockmon",
102	.priv_size		= sizeof(struct vsockmon),
103	.setup			= vsockmon_setup,
104};
105
106static __init int vsockmon_register(void)
107{
108	return rtnl_link_register(&vsockmon_link_ops);
109}
110
111static __exit void vsockmon_unregister(void)
112{
113	rtnl_link_unregister(&vsockmon_link_ops);
114}
115
116module_init(vsockmon_register);
117module_exit(vsockmon_unregister);
118
119MODULE_LICENSE("GPL v2");
120MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
121MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
122MODULE_ALIAS_RTNL_LINK("vsockmon");