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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");
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 struct rtnl_link_stats64 *
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 return stats;
91}
92
93static u32 always_on(struct net_device *dev)
94{
95 return 1;
96}
97
98static const struct ethtool_ops nlmon_ethtool_ops = {
99 .get_link = always_on,
100};
101
102static const struct net_device_ops nlmon_ops = {
103 .ndo_init = nlmon_dev_init,
104 .ndo_uninit = nlmon_dev_uninit,
105 .ndo_open = nlmon_open,
106 .ndo_stop = nlmon_close,
107 .ndo_start_xmit = nlmon_xmit,
108 .ndo_get_stats64 = nlmon_get_stats64,
109};
110
111static void nlmon_setup(struct net_device *dev)
112{
113 dev->type = ARPHRD_NETLINK;
114 dev->priv_flags |= IFF_NO_QUEUE;
115
116 dev->netdev_ops = &nlmon_ops;
117 dev->ethtool_ops = &nlmon_ethtool_ops;
118 dev->destructor = free_netdev;
119
120 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
121 NETIF_F_HIGHDMA | NETIF_F_LLTX;
122 dev->flags = IFF_NOARP;
123
124 /* That's rather a softlimit here, which, of course,
125 * can be altered. Not a real MTU, but what is to be
126 * expected in most cases.
127 */
128 dev->mtu = NLMSG_GOODSIZE;
129 dev->min_mtu = sizeof(struct nlmsghdr);
130}
131
132static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[])
133{
134 if (tb[IFLA_ADDRESS])
135 return -EINVAL;
136 return 0;
137}
138
139static struct rtnl_link_ops nlmon_link_ops __read_mostly = {
140 .kind = "nlmon",
141 .priv_size = sizeof(struct nlmon),
142 .setup = nlmon_setup,
143 .validate = nlmon_validate,
144};
145
146static __init int nlmon_register(void)
147{
148 return rtnl_link_register(&nlmon_link_ops);
149}
150
151static __exit void nlmon_unregister(void)
152{
153 rtnl_link_unregister(&nlmon_link_ops);
154}
155
156module_init(nlmon_register);
157module_exit(nlmon_unregister);
158
159MODULE_LICENSE("GPL v2");
160MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
161MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>");
162MODULE_DESCRIPTION("Netlink monitoring device");
163MODULE_ALIAS_RTNL_LINK("nlmon");