[mirror_ubuntu-jammy-kernel.git] / drivers / net / nlmon.c

// SPDX-License-Identifier: GPL-2.0-only
#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>

static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev)
{
	dev_lstats_add(dev, skb->len);

	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)
{
	u64 packets, bytes;

	dev_lstats_read(dev, &packets, &bytes);

	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");
Commit	Line	Data
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)
e4fc408e DB	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)
e4fc408e DB	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	}
e4fc408e DB	49
bc1f4470	50	static void
e4fc408e DB	51	nlmon_get_stats64(struct net_device dev, struct rtnl_link_stats64 stats)
e4fc408e DB	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	};
e4fc408e DB	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 \|
b7d47ca2 DB	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	}
e4fc408e DB	102
a8b8a889 MS	103	static int nlmon_validate(struct nlattr tb[], struct nlattr data[],
a8b8a889 MS	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");