xref: /kernel/linux/linux-6.6/drivers/net/vsockmon.c (revision 62306a36) 
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");
140