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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/netdevice.h>
6#include <linux/netlink.h>
7#include <net/net_namespace.h>
8#include <linux/if_arp.h>
9#include <net/rtnetlink.h>
10
11static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev)
12{
13 dev_lstats_add(dev, skb->len);
14
15 dev_kfree_skb(skb);
16
17 return NETDEV_TX_OK;
18}
19
20static int nlmon_dev_init(struct net_device *dev)
21{
22 dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
23 return dev->lstats == NULL ? -ENOMEM : 0;
24}
25
26static void nlmon_dev_uninit(struct net_device *dev)
27{
28 free_percpu(dev->lstats);
29}
30
31struct nlmon {
32 struct netlink_tap nt;
33};
34
35static int nlmon_open(struct net_device *dev)
36{
37 struct nlmon *nlmon = netdev_priv(dev);
38
39 nlmon->nt.dev = dev;
40 nlmon->nt.module = THIS_MODULE;
41 return netlink_add_tap(&nlmon->nt);
42}
43
44static int nlmon_close(struct net_device *dev)
45{
46 struct nlmon *nlmon = netdev_priv(dev);
47
48 return netlink_remove_tap(&nlmon->nt);
49}
50
51static void
52nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
53{
54 u64 packets, bytes;
55
56 dev_lstats_read(dev, &packets, &bytes);
57
58 stats->rx_packets = packets;
59 stats->tx_packets = 0;
60
61 stats->rx_bytes = bytes;
62 stats->tx_bytes = 0;
63}
64
65static u32 always_on(struct net_device *dev)
66{
67 return 1;
68}
69
70static const struct ethtool_ops nlmon_ethtool_ops = {
71 .get_link = always_on,
72};
73
74static const struct net_device_ops nlmon_ops = {
75 .ndo_init = nlmon_dev_init,
76 .ndo_uninit = nlmon_dev_uninit,
77 .ndo_open = nlmon_open,
78 .ndo_stop = nlmon_close,
79 .ndo_start_xmit = nlmon_xmit,
80 .ndo_get_stats64 = nlmon_get_stats64,
81};
82
83static void nlmon_setup(struct net_device *dev)
84{
85 dev->type = ARPHRD_NETLINK;
86 dev->priv_flags |= IFF_NO_QUEUE;
87
88 dev->netdev_ops = &nlmon_ops;
89 dev->ethtool_ops = &nlmon_ethtool_ops;
90 dev->needs_free_netdev = true;
91
92 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
93 NETIF_F_HIGHDMA | NETIF_F_LLTX;
94 dev->flags = IFF_NOARP;
95
96 /* That's rather a softlimit here, which, of course,
97 * can be altered. Not a real MTU, but what is to be
98 * expected in most cases.
99 */
100 dev->mtu = NLMSG_GOODSIZE;
101 dev->min_mtu = sizeof(struct nlmsghdr);
102}
103
104static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[],
105 struct netlink_ext_ack *extack)
106{
107 if (tb[IFLA_ADDRESS])
108 return -EINVAL;
109 return 0;
110}
111
112static struct rtnl_link_ops nlmon_link_ops __read_mostly = {
113 .kind = "nlmon",
114 .priv_size = sizeof(struct nlmon),
115 .setup = nlmon_setup,
116 .validate = nlmon_validate,
117};
118
119static __init int nlmon_register(void)
120{
121 return rtnl_link_register(&nlmon_link_ops);
122}
123
124static __exit void nlmon_unregister(void)
125{
126 rtnl_link_unregister(&nlmon_link_ops);
127}
128
129module_init(nlmon_register);
130module_exit(nlmon_unregister);
131
132MODULE_LICENSE("GPL v2");
133MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
134MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>");
135MODULE_DESCRIPTION("Netlink monitoring device");
136MODULE_ALIAS_RTNL_LINK("nlmon");
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/netdevice.h>
6#include <linux/netlink.h>
7#include <net/net_namespace.h>
8#include <linux/if_arp.h>
9#include <net/rtnetlink.h>
10
11static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev)
12{
13 dev_lstats_add(dev, skb->len);
14
15 dev_kfree_skb(skb);
16
17 return NETDEV_TX_OK;
18}
19
20struct nlmon {
21 struct netlink_tap nt;
22};
23
24static int nlmon_open(struct net_device *dev)
25{
26 struct nlmon *nlmon = netdev_priv(dev);
27
28 nlmon->nt.dev = dev;
29 nlmon->nt.module = THIS_MODULE;
30 return netlink_add_tap(&nlmon->nt);
31}
32
33static int nlmon_close(struct net_device *dev)
34{
35 struct nlmon *nlmon = netdev_priv(dev);
36
37 return netlink_remove_tap(&nlmon->nt);
38}
39
40static void
41nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
42{
43 dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
44}
45
46static u32 always_on(struct net_device *dev)
47{
48 return 1;
49}
50
51static const struct ethtool_ops nlmon_ethtool_ops = {
52 .get_link = always_on,
53};
54
55static const struct net_device_ops nlmon_ops = {
56 .ndo_open = nlmon_open,
57 .ndo_stop = nlmon_close,
58 .ndo_start_xmit = nlmon_xmit,
59 .ndo_get_stats64 = nlmon_get_stats64,
60};
61
62static void nlmon_setup(struct net_device *dev)
63{
64 dev->type = ARPHRD_NETLINK;
65 dev->priv_flags |= IFF_NO_QUEUE;
66 dev->lltx = true;
67
68 dev->netdev_ops = &nlmon_ops;
69 dev->ethtool_ops = &nlmon_ethtool_ops;
70 dev->needs_free_netdev = true;
71
72 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
73 dev->flags = IFF_NOARP;
74 dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
75
76 /* That's rather a softlimit here, which, of course,
77 * can be altered. Not a real MTU, but what is to be
78 * expected in most cases.
79 */
80 dev->mtu = NLMSG_GOODSIZE;
81 dev->min_mtu = sizeof(struct nlmsghdr);
82}
83
84static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[],
85 struct netlink_ext_ack *extack)
86{
87 if (tb[IFLA_ADDRESS])
88 return -EINVAL;
89 return 0;
90}
91
92static struct rtnl_link_ops nlmon_link_ops __read_mostly = {
93 .kind = "nlmon",
94 .priv_size = sizeof(struct nlmon),
95 .setup = nlmon_setup,
96 .validate = nlmon_validate,
97};
98
99static __init int nlmon_register(void)
100{
101 return rtnl_link_register(&nlmon_link_ops);
102}
103
104static __exit void nlmon_unregister(void)
105{
106 rtnl_link_unregister(&nlmon_link_ops);
107}
108
109module_init(nlmon_register);
110module_exit(nlmon_unregister);
111
112MODULE_LICENSE("GPL v2");
113MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
114MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>");
115MODULE_DESCRIPTION("Netlink monitoring device");
116MODULE_ALIAS_RTNL_LINK("nlmon");