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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 WRITE_ONCE(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 dev->lltx = true;
87
88 dev->netdev_ops = &vsockmon_ops;
89 dev->ethtool_ops = &vsockmon_ethtool_ops;
90 dev->needs_free_netdev = true;
91
92 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
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 <[email protected]>");
121MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
122MODULE_ALIAS_RTNL_LINK("vsockmon");