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