Commit | Line | Data |
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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 | { | |
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 | ||
e4fc408e DB |
25 | static int nlmon_dev_init(struct net_device *dev) |
26 | { | |
1c213bd2 | 27 | dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats); |
e4fc408e DB |
28 | return dev->lstats == NULL ? -ENOMEM : 0; |
29 | } | |
30 | ||
31 | static void nlmon_dev_uninit(struct net_device *dev) | |
32 | { | |
33 | free_percpu(dev->lstats); | |
34 | } | |
35 | ||
7e6d4da8 JP |
36 | struct nlmon { |
37 | struct netlink_tap nt; | |
38 | }; | |
e4fc408e DB |
39 | |
40 | static int nlmon_open(struct net_device *dev) | |
41 | { | |
7e6d4da8 JP |
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); | |
e4fc408e DB |
47 | } |
48 | ||
49 | static int nlmon_close(struct net_device *dev) | |
50 | { | |
7e6d4da8 JP |
51 | struct nlmon *nlmon = netdev_priv(dev); |
52 | ||
53 | return netlink_remove_tap(&nlmon->nt); | |
e4fc408e DB |
54 | } |
55 | ||
bc1f4470 | 56 | static void |
e4fc408e DB |
57 | nlmon_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 { | |
57a7744e | 70 | start = u64_stats_fetch_begin_irq(&nl_stats->syncp); |
e4fc408e DB |
71 | tbytes = nl_stats->bytes; |
72 | tpackets = nl_stats->packets; | |
57a7744e | 73 | } while (u64_stats_fetch_retry_irq(&nl_stats->syncp, start)); |
e4fc408e DB |
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; | |
e4fc408e DB |
84 | } |
85 | ||
86 | static u32 always_on(struct net_device *dev) | |
87 | { | |
88 | return 1; | |
89 | } | |
90 | ||
91 | static const struct ethtool_ops nlmon_ethtool_ops = { | |
92 | .get_link = always_on, | |
93 | }; | |
94 | ||
95 | static 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, | |
e4fc408e DB |
102 | }; |
103 | ||
e4fc408e DB |
104 | static void nlmon_setup(struct net_device *dev) |
105 | { | |
106 | dev->type = ARPHRD_NETLINK; | |
85773a61 | 107 | dev->priv_flags |= IFF_NO_QUEUE; |
e4fc408e DB |
108 | |
109 | dev->netdev_ops = &nlmon_ops; | |
110 | dev->ethtool_ops = &nlmon_ethtool_ops; | |
cf124db5 | 111 | dev->needs_free_netdev = true; |
e4fc408e | 112 | |
b7d47ca2 DB |
113 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | |
114 | NETIF_F_HIGHDMA | NETIF_F_LLTX; | |
e4fc408e DB |
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; | |
e82621e3 | 122 | dev->min_mtu = sizeof(struct nlmsghdr); |
e4fc408e DB |
123 | } |
124 | ||
a8b8a889 MS |
125 | static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[], |
126 | struct netlink_ext_ack *extack) | |
e4fc408e | 127 | { |
7e6d4da8 JP |
128 | if (tb[IFLA_ADDRESS]) |
129 | return -EINVAL; | |
130 | return 0; | |
131 | } | |
e4fc408e | 132 | |
7e6d4da8 JP |
133 | static 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 | }; | |
e4fc408e | 139 | |
7e6d4da8 JP |
140 | static __init int nlmon_register(void) |
141 | { | |
142 | return rtnl_link_register(&nlmon_link_ops); | |
e4fc408e DB |
143 | } |
144 | ||
145 | static __exit void nlmon_unregister(void) | |
146 | { | |
7e6d4da8 | 147 | rtnl_link_unregister(&nlmon_link_ops); |
e4fc408e DB |
148 | } |
149 | ||
150 | module_init(nlmon_register); | |
151 | module_exit(nlmon_unregister); | |
152 | ||
153 | MODULE_LICENSE("GPL v2"); | |
154 | MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); | |
155 | MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>"); | |
156 | MODULE_DESCRIPTION("Netlink monitoring device"); | |
7e6d4da8 | 157 | MODULE_ALIAS_RTNL_LINK("nlmon"); |