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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e4fc408e DB |
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> | |
7e6d4da8 | 8 | #include <net/rtnetlink.h> |
e4fc408e | 9 | |
e4fc408e DB |
10 | static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev) |
11 | { | |
3ed91226 | 12 | dev_lstats_add(dev, skb->len); |
e4fc408e DB |
13 | |
14 | dev_kfree_skb(skb); | |
15 | ||
16 | return NETDEV_TX_OK; | |
17 | } | |
18 | ||
e4fc408e DB |
19 | static int nlmon_dev_init(struct net_device *dev) |
20 | { | |
1c213bd2 | 21 | dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats); |
e4fc408e DB |
22 | return dev->lstats == NULL ? -ENOMEM : 0; |
23 | } | |
24 | ||
25 | static void nlmon_dev_uninit(struct net_device *dev) | |
26 | { | |
27 | free_percpu(dev->lstats); | |
28 | } | |
29 | ||
7e6d4da8 JP |
30 | struct nlmon { |
31 | struct netlink_tap nt; | |
32 | }; | |
e4fc408e DB |
33 | |
34 | static int nlmon_open(struct net_device *dev) | |
35 | { | |
7e6d4da8 JP |
36 | struct nlmon *nlmon = netdev_priv(dev); |
37 | ||
38 | nlmon->nt.dev = dev; | |
39 | nlmon->nt.module = THIS_MODULE; | |
40 | return netlink_add_tap(&nlmon->nt); | |
e4fc408e DB |
41 | } |
42 | ||
43 | static int nlmon_close(struct net_device *dev) | |
44 | { | |
7e6d4da8 JP |
45 | struct nlmon *nlmon = netdev_priv(dev); |
46 | ||
47 | return netlink_remove_tap(&nlmon->nt); | |
e4fc408e DB |
48 | } |
49 | ||
bc1f4470 | 50 | static void |
e4fc408e DB |
51 | nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) |
52 | { | |
3ed91226 | 53 | u64 packets, bytes; |
e4fc408e | 54 | |
3ed91226 | 55 | dev_lstats_read(dev, &packets, &bytes); |
e4fc408e DB |
56 | |
57 | stats->rx_packets = packets; | |
58 | stats->tx_packets = 0; | |
59 | ||
60 | stats->rx_bytes = bytes; | |
61 | stats->tx_bytes = 0; | |
e4fc408e DB |
62 | } |
63 | ||
64 | static u32 always_on(struct net_device *dev) | |
65 | { | |
66 | return 1; | |
67 | } | |
68 | ||
69 | static const struct ethtool_ops nlmon_ethtool_ops = { | |
70 | .get_link = always_on, | |
71 | }; | |
72 | ||
73 | static const struct net_device_ops nlmon_ops = { | |
74 | .ndo_init = nlmon_dev_init, | |
75 | .ndo_uninit = nlmon_dev_uninit, | |
76 | .ndo_open = nlmon_open, | |
77 | .ndo_stop = nlmon_close, | |
78 | .ndo_start_xmit = nlmon_xmit, | |
79 | .ndo_get_stats64 = nlmon_get_stats64, | |
e4fc408e DB |
80 | }; |
81 | ||
e4fc408e DB |
82 | static void nlmon_setup(struct net_device *dev) |
83 | { | |
84 | dev->type = ARPHRD_NETLINK; | |
85773a61 | 85 | dev->priv_flags |= IFF_NO_QUEUE; |
e4fc408e DB |
86 | |
87 | dev->netdev_ops = &nlmon_ops; | |
88 | dev->ethtool_ops = &nlmon_ethtool_ops; | |
cf124db5 | 89 | dev->needs_free_netdev = true; |
e4fc408e | 90 | |
b7d47ca2 DB |
91 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | |
92 | NETIF_F_HIGHDMA | NETIF_F_LLTX; | |
e4fc408e DB |
93 | dev->flags = IFF_NOARP; |
94 | ||
95 | /* That's rather a softlimit here, which, of course, | |
96 | * can be altered. Not a real MTU, but what is to be | |
97 | * expected in most cases. | |
98 | */ | |
99 | dev->mtu = NLMSG_GOODSIZE; | |
e82621e3 | 100 | dev->min_mtu = sizeof(struct nlmsghdr); |
e4fc408e DB |
101 | } |
102 | ||
a8b8a889 MS |
103 | static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[], |
104 | struct netlink_ext_ack *extack) | |
e4fc408e | 105 | { |
7e6d4da8 JP |
106 | if (tb[IFLA_ADDRESS]) |
107 | return -EINVAL; | |
108 | return 0; | |
109 | } | |
e4fc408e | 110 | |
7e6d4da8 JP |
111 | static struct rtnl_link_ops nlmon_link_ops __read_mostly = { |
112 | .kind = "nlmon", | |
113 | .priv_size = sizeof(struct nlmon), | |
114 | .setup = nlmon_setup, | |
115 | .validate = nlmon_validate, | |
116 | }; | |
e4fc408e | 117 | |
7e6d4da8 JP |
118 | static __init int nlmon_register(void) |
119 | { | |
120 | return rtnl_link_register(&nlmon_link_ops); | |
e4fc408e DB |
121 | } |
122 | ||
123 | static __exit void nlmon_unregister(void) | |
124 | { | |
7e6d4da8 | 125 | rtnl_link_unregister(&nlmon_link_ops); |
e4fc408e DB |
126 | } |
127 | ||
128 | module_init(nlmon_register); | |
129 | module_exit(nlmon_unregister); | |
130 | ||
131 | MODULE_LICENSE("GPL v2"); | |
132 | MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); | |
133 | MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>"); | |
134 | MODULE_DESCRIPTION("Netlink monitoring device"); | |
7e6d4da8 | 135 | MODULE_ALIAS_RTNL_LINK("nlmon"); |