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
 16static int vsockmon_dev_init(struct net_device *dev)
 17{
 18	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 19	if (!dev->lstats)
 20		return -ENOMEM;
 21	return 0;
 22}
 23
 24static void vsockmon_dev_uninit(struct net_device *dev)
 25{
 26	free_percpu(dev->lstats);
 27}
 28
 29struct vsockmon {
 30	struct vsock_tap vt;
 31};
 32
 33static int vsockmon_open(struct net_device *dev)
 34{
 35	struct vsockmon *vsockmon = netdev_priv(dev);
 36
 37	vsockmon->vt.dev = dev;
 38	vsockmon->vt.module = THIS_MODULE;
 39	return vsock_add_tap(&vsockmon->vt);
 40}
 41
 42static int vsockmon_close(struct net_device *dev)
 43{
 44	struct vsockmon *vsockmon = netdev_priv(dev);
 45
 46	return vsock_remove_tap(&vsockmon->vt);
 47}
 48
 49static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
 50{
 51	dev_lstats_add(dev, skb->len);
 52
 53	dev_kfree_skb(skb);
 54
 55	return NETDEV_TX_OK;
 56}
 57
 58static void
 59vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 60{
 61	dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
 62
 63	stats->tx_packets = 0;
 64	stats->tx_bytes = 0;
 65}
 66
 67static int vsockmon_is_valid_mtu(int new_mtu)
 68{
 69	return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
 70}
 71
 72static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
 73{
 74	if (!vsockmon_is_valid_mtu(new_mtu))
 75		return -EINVAL;
 76
 77	dev->mtu = new_mtu;
 78	return 0;
 79}
 80
 81static const struct net_device_ops vsockmon_ops = {
 82	.ndo_init = vsockmon_dev_init,
 83	.ndo_uninit = vsockmon_dev_uninit,
 84	.ndo_open = vsockmon_open,
 85	.ndo_stop = vsockmon_close,
 86	.ndo_start_xmit = vsockmon_xmit,
 87	.ndo_get_stats64 = vsockmon_get_stats64,
 88	.ndo_change_mtu = vsockmon_change_mtu,
 89};
 90
 91static u32 always_on(struct net_device *dev)
 92{
 93	return 1;
 94}
 95
 96static const struct ethtool_ops vsockmon_ethtool_ops = {
 97	.get_link = always_on,
 98};
 99
100static void vsockmon_setup(struct net_device *dev)
101{
102	dev->type = ARPHRD_VSOCKMON;
103	dev->priv_flags |= IFF_NO_QUEUE;
104
105	dev->netdev_ops	= &vsockmon_ops;
106	dev->ethtool_ops = &vsockmon_ethtool_ops;
107	dev->needs_free_netdev = true;
108
109	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
110			NETIF_F_HIGHDMA | NETIF_F_LLTX;
111
112	dev->flags = IFF_NOARP;
113
114	dev->mtu = DEFAULT_MTU;
115}
116
117static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
118	.kind			= "vsockmon",
119	.priv_size		= sizeof(struct vsockmon),
120	.setup			= vsockmon_setup,
121};
122
123static __init int vsockmon_register(void)
124{
125	return rtnl_link_register(&vsockmon_link_ops);
126}
127
128static __exit void vsockmon_unregister(void)
129{
130	rtnl_link_unregister(&vsockmon_link_ops);
131}
132
133module_init(vsockmon_register);
134module_exit(vsockmon_unregister);
135
136MODULE_LICENSE("GPL v2");
137MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
138MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
139MODULE_ALIAS_RTNL_LINK("vsockmon");