1// SPDX-License-Identifier: GPL-2.0-only
  2#include <linux/module.h>
  3#include <linux/kernel.h>
  4#include <linux/if_arp.h>
  5#include <net/rtnetlink.h>
  6#include <net/sock.h>
  7#include <net/af_vsock.h>
  8#include <uapi/linux/vsockmon.h>
  9#include <linux/virtio_vsock.h>
 10
 11/* Virtio transport max packet size plus header */
 12#define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
 13		     sizeof(struct af_vsockmon_hdr))
 14
 15static int vsockmon_dev_init(struct net_device *dev)
 16{
 17	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 18	if (!dev->lstats)
 19		return -ENOMEM;
 20	return 0;
 21}
 22
 23static void vsockmon_dev_uninit(struct net_device *dev)
 24{
 25	free_percpu(dev->lstats);
 26}
 27
 28struct vsockmon {
 29	struct vsock_tap vt;
 30};
 31
 32static int vsockmon_open(struct net_device *dev)
 33{
 34	struct vsockmon *vsockmon = netdev_priv(dev);
 35
 36	vsockmon->vt.dev = dev;
 37	vsockmon->vt.module = THIS_MODULE;
 38	return vsock_add_tap(&vsockmon->vt);
 39}
 40
 41static int vsockmon_close(struct net_device *dev)
 42{
 43	struct vsockmon *vsockmon = netdev_priv(dev);
 44
 45	return vsock_remove_tap(&vsockmon->vt);
 46}
 47
 48static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
 49{
 50	dev_lstats_add(dev, skb->len);
 51
 52	dev_kfree_skb(skb);
 53
 54	return NETDEV_TX_OK;
 55}
 56
 57static void
 58vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 59{
 60	dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
 61
 62	stats->tx_packets = 0;
 63	stats->tx_bytes = 0;
 64}
 65
 66static int vsockmon_is_valid_mtu(int new_mtu)
 67{
 68	return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
 69}
 70
 71static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
 72{
 73	if (!vsockmon_is_valid_mtu(new_mtu))
 74		return -EINVAL;
 75
 76	dev->mtu = new_mtu;
 77	return 0;
 78}
 79
 80static const struct net_device_ops vsockmon_ops = {
 81	.ndo_init = vsockmon_dev_init,
 82	.ndo_uninit = vsockmon_dev_uninit,
 83	.ndo_open = vsockmon_open,
 84	.ndo_stop = vsockmon_close,
 85	.ndo_start_xmit = vsockmon_xmit,
 86	.ndo_get_stats64 = vsockmon_get_stats64,
 87	.ndo_change_mtu = vsockmon_change_mtu,
 88};
 89
 90static u32 always_on(struct net_device *dev)
 91{
 92	return 1;
 93}
 94
 95static const struct ethtool_ops vsockmon_ethtool_ops = {
 96	.get_link = always_on,
 97};
 98
 99static void vsockmon_setup(struct net_device *dev)
100{
101	dev->type = ARPHRD_VSOCKMON;
102	dev->priv_flags |= IFF_NO_QUEUE;
103
104	dev->netdev_ops	= &vsockmon_ops;
105	dev->ethtool_ops = &vsockmon_ethtool_ops;
106	dev->needs_free_netdev = true;
107
108	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
109			NETIF_F_HIGHDMA | NETIF_F_LLTX;
110
111	dev->flags = IFF_NOARP;
112
113	dev->mtu = DEFAULT_MTU;
114}
115
116static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
117	.kind			= "vsockmon",
118	.priv_size		= sizeof(struct vsockmon),
119	.setup			= vsockmon_setup,
120};
121
122static __init int vsockmon_register(void)
123{
124	return rtnl_link_register(&vsockmon_link_ops);
125}
126
127static __exit void vsockmon_unregister(void)
128{
129	rtnl_link_unregister(&vsockmon_link_ops);
130}
131
132module_init(vsockmon_register);
133module_exit(vsockmon_unregister);
134
135MODULE_LICENSE("GPL v2");
136MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
137MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
138MODULE_ALIAS_RTNL_LINK("vsockmon");