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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#include <linux/module.h>
2#include <linux/kernel.h>
3#include <linux/netdevice.h>
4#include <linux/netlink.h>
5#include <net/net_namespace.h>
6#include <linux/if_arp.h>
7#include <net/rtnetlink.h>
8
9struct pcpu_lstats {
10 u64 packets;
11 u64 bytes;
12 struct u64_stats_sync syncp;
13};
14
15static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev)
16{
17 int len = skb->len;
18 struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
19
20 u64_stats_update_begin(&stats->syncp);
21 stats->bytes += len;
22 stats->packets++;
23 u64_stats_update_end(&stats->syncp);
24
25 dev_kfree_skb(skb);
26
27 return NETDEV_TX_OK;
28}
29
30static int nlmon_dev_init(struct net_device *dev)
31{
32 dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
33 return dev->lstats == NULL ? -ENOMEM : 0;
34}
35
36static void nlmon_dev_uninit(struct net_device *dev)
37{
38 free_percpu(dev->lstats);
39}
40
41struct nlmon {
42 struct netlink_tap nt;
43};
44
45static int nlmon_open(struct net_device *dev)
46{
47 struct nlmon *nlmon = netdev_priv(dev);
48
49 nlmon->nt.dev = dev;
50 nlmon->nt.module = THIS_MODULE;
51 return netlink_add_tap(&nlmon->nt);
52}
53
54static int nlmon_close(struct net_device *dev)
55{
56 struct nlmon *nlmon = netdev_priv(dev);
57
58 return netlink_remove_tap(&nlmon->nt);
59}
60
61static void
62nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
63{
64 int i;
65 u64 bytes = 0, packets = 0;
66
67 for_each_possible_cpu(i) {
68 const struct pcpu_lstats *nl_stats;
69 u64 tbytes, tpackets;
70 unsigned int start;
71
72 nl_stats = per_cpu_ptr(dev->lstats, i);
73
74 do {
75 start = u64_stats_fetch_begin_irq(&nl_stats->syncp);
76 tbytes = nl_stats->bytes;
77 tpackets = nl_stats->packets;
78 } while (u64_stats_fetch_retry_irq(&nl_stats->syncp, start));
79
80 packets += tpackets;
81 bytes += tbytes;
82 }
83
84 stats->rx_packets = packets;
85 stats->tx_packets = 0;
86
87 stats->rx_bytes = bytes;
88 stats->tx_bytes = 0;
89}
90
91static u32 always_on(struct net_device *dev)
92{
93 return 1;
94}
95
96static const struct ethtool_ops nlmon_ethtool_ops = {
97 .get_link = always_on,
98};
99
100static const struct net_device_ops nlmon_ops = {
101 .ndo_init = nlmon_dev_init,
102 .ndo_uninit = nlmon_dev_uninit,
103 .ndo_open = nlmon_open,
104 .ndo_stop = nlmon_close,
105 .ndo_start_xmit = nlmon_xmit,
106 .ndo_get_stats64 = nlmon_get_stats64,
107};
108
109static void nlmon_setup(struct net_device *dev)
110{
111 dev->type = ARPHRD_NETLINK;
112 dev->priv_flags |= IFF_NO_QUEUE;
113
114 dev->netdev_ops = &nlmon_ops;
115 dev->ethtool_ops = &nlmon_ethtool_ops;
116 dev->needs_free_netdev = true;
117
118 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
119 NETIF_F_HIGHDMA | NETIF_F_LLTX;
120 dev->flags = IFF_NOARP;
121
122 /* That's rather a softlimit here, which, of course,
123 * can be altered. Not a real MTU, but what is to be
124 * expected in most cases.
125 */
126 dev->mtu = NLMSG_GOODSIZE;
127 dev->min_mtu = sizeof(struct nlmsghdr);
128}
129
130static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[],
131 struct netlink_ext_ack *extack)
132{
133 if (tb[IFLA_ADDRESS])
134 return -EINVAL;
135 return 0;
136}
137
138static struct rtnl_link_ops nlmon_link_ops __read_mostly = {
139 .kind = "nlmon",
140 .priv_size = sizeof(struct nlmon),
141 .setup = nlmon_setup,
142 .validate = nlmon_validate,
143};
144
145static __init int nlmon_register(void)
146{
147 return rtnl_link_register(&nlmon_link_ops);
148}
149
150static __exit void nlmon_unregister(void)
151{
152 rtnl_link_unregister(&nlmon_link_ops);
153}
154
155module_init(nlmon_register);
156module_exit(nlmon_unregister);
157
158MODULE_LICENSE("GPL v2");
159MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
160MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>");
161MODULE_DESCRIPTION("Netlink monitoring device");
162MODULE_ALIAS_RTNL_LINK("nlmon");