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