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>
12 struct u64_stats_sync syncp
;
15 static netdev_tx_t
nlmon_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
18 struct pcpu_lstats
*stats
= this_cpu_ptr(dev
->lstats
);
20 u64_stats_update_begin(&stats
->syncp
);
23 u64_stats_update_end(&stats
->syncp
);
30 static int nlmon_is_valid_mtu(int new_mtu
)
32 /* Note that in netlink we do not really have an upper limit. On
33 * default, we use NLMSG_GOODSIZE. Here at least we should make
34 * sure that it's at least the header size.
36 return new_mtu
>= (int) sizeof(struct nlmsghdr
);
39 static int nlmon_change_mtu(struct net_device
*dev
, int new_mtu
)
41 if (!nlmon_is_valid_mtu(new_mtu
))
48 static int nlmon_dev_init(struct net_device
*dev
)
50 dev
->lstats
= alloc_percpu(struct pcpu_lstats
);
52 return dev
->lstats
== NULL
? -ENOMEM
: 0;
55 static void nlmon_dev_uninit(struct net_device
*dev
)
57 free_percpu(dev
->lstats
);
61 struct netlink_tap nt
;
64 static int nlmon_open(struct net_device
*dev
)
66 struct nlmon
*nlmon
= netdev_priv(dev
);
69 nlmon
->nt
.module
= THIS_MODULE
;
70 return netlink_add_tap(&nlmon
->nt
);
73 static int nlmon_close(struct net_device
*dev
)
75 struct nlmon
*nlmon
= netdev_priv(dev
);
77 return netlink_remove_tap(&nlmon
->nt
);
80 static struct rtnl_link_stats64
*
81 nlmon_get_stats64(struct net_device
*dev
, struct rtnl_link_stats64
*stats
)
84 u64 bytes
= 0, packets
= 0;
86 for_each_possible_cpu(i
) {
87 const struct pcpu_lstats
*nl_stats
;
91 nl_stats
= per_cpu_ptr(dev
->lstats
, i
);
94 start
= u64_stats_fetch_begin_bh(&nl_stats
->syncp
);
95 tbytes
= nl_stats
->bytes
;
96 tpackets
= nl_stats
->packets
;
97 } while (u64_stats_fetch_retry_bh(&nl_stats
->syncp
, start
));
103 stats
->rx_packets
= packets
;
104 stats
->tx_packets
= 0;
106 stats
->rx_bytes
= bytes
;
112 static u32
always_on(struct net_device
*dev
)
117 static const struct ethtool_ops nlmon_ethtool_ops
= {
118 .get_link
= always_on
,
121 static const struct net_device_ops nlmon_ops
= {
122 .ndo_init
= nlmon_dev_init
,
123 .ndo_uninit
= nlmon_dev_uninit
,
124 .ndo_open
= nlmon_open
,
125 .ndo_stop
= nlmon_close
,
126 .ndo_start_xmit
= nlmon_xmit
,
127 .ndo_get_stats64
= nlmon_get_stats64
,
128 .ndo_change_mtu
= nlmon_change_mtu
,
131 static void nlmon_setup(struct net_device
*dev
)
133 dev
->type
= ARPHRD_NETLINK
;
134 dev
->tx_queue_len
= 0;
136 dev
->netdev_ops
= &nlmon_ops
;
137 dev
->ethtool_ops
= &nlmon_ethtool_ops
;
138 dev
->destructor
= free_netdev
;
140 dev
->features
= NETIF_F_FRAGLIST
| NETIF_F_HIGHDMA
;
141 dev
->flags
= IFF_NOARP
;
143 /* That's rather a softlimit here, which, of course,
144 * can be altered. Not a real MTU, but what is to be
145 * expected in most cases.
147 dev
->mtu
= NLMSG_GOODSIZE
;
150 static int nlmon_validate(struct nlattr
*tb
[], struct nlattr
*data
[])
152 if (tb
[IFLA_ADDRESS
])
157 static struct rtnl_link_ops nlmon_link_ops __read_mostly
= {
159 .priv_size
= sizeof(struct nlmon
),
160 .setup
= nlmon_setup
,
161 .validate
= nlmon_validate
,
164 static __init
int nlmon_register(void)
166 return rtnl_link_register(&nlmon_link_ops
);
169 static __exit
void nlmon_unregister(void)
171 rtnl_link_unregister(&nlmon_link_ops
);
174 module_init(nlmon_register
);
175 module_exit(nlmon_unregister
);
177 MODULE_LICENSE("GPL v2");
178 MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
179 MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>");
180 MODULE_DESCRIPTION("Netlink monitoring device");
181 MODULE_ALIAS_RTNL_LINK("nlmon");