[mirror_ubuntu-artful-kernel.git] / net / netfilter / nf_tables_netdev.c

/*
 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <net/netfilter/nf_tables.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/netfilter/nf_tables_ipv4.h>
#include <net/netfilter/nf_tables_ipv6.h>

static inline void
nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
			    struct sk_buff *skb,
			    const struct nf_hook_state *state)
{
	struct iphdr *iph, _iph;
	u32 len, thoff;

	nft_set_pktinfo(pkt, skb, state);

	iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
				 &_iph);
	if (!iph)
		return;

	iph = ip_hdr(skb);
	if (iph->ihl < 5 || iph->version != 4)
		return;

	len = ntohs(iph->tot_len);
	thoff = iph->ihl * 4;
	if (skb->len < len)
		return;
	else if (len < thoff)
		return;

	pkt->tprot = iph->protocol;
	pkt->xt.thoff = thoff;
	pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
}

static inline void
__nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
			      struct sk_buff *skb,
			      const struct nf_hook_state *state)
{
#if IS_ENABLED(CONFIG_IPV6)
	struct ipv6hdr *ip6h, _ip6h;
	unsigned int thoff = 0;
	unsigned short frag_off;
	int protohdr;
	u32 pkt_len;

	ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
				  &_ip6h);
	if (!ip6h)
		return;

	if (ip6h->version != 6)
		return;

	pkt_len = ntohs(ip6h->payload_len);
	if (pkt_len + sizeof(*ip6h) > skb->len)
		return;

	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
	if (protohdr < 0)
                return;

	pkt->tprot = protohdr;
	pkt->xt.thoff = thoff;
	pkt->xt.fragoff = frag_off;
#endif
}

static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
					       struct sk_buff *skb,
					       const struct nf_hook_state *state)
{
	nft_set_pktinfo(pkt, skb, state);
	__nft_netdev_set_pktinfo_ipv6(pkt, skb, state);
}

static unsigned int
nft_do_chain_netdev(void *priv, struct sk_buff *skb,
		    const struct nf_hook_state *state)
{
	struct nft_pktinfo pkt;

	switch (eth_hdr(skb)->h_proto) {
	case htons(ETH_P_IP):
		nft_netdev_set_pktinfo_ipv4(&pkt, skb, state);
		break;
	case htons(ETH_P_IPV6):
		nft_netdev_set_pktinfo_ipv6(&pkt, skb, state);
		break;
	default:
		nft_set_pktinfo(&pkt, skb, state);
		break;
	}

	return nft_do_chain(&pkt, priv);
}

static struct nft_af_info nft_af_netdev __read_mostly = {
	.family		= NFPROTO_NETDEV,
	.nhooks		= NF_NETDEV_NUMHOOKS,
	.owner		= THIS_MODULE,
	.flags		= NFT_AF_NEEDS_DEV,
	.nops		= 1,
	.hooks		= {
		[NF_NETDEV_INGRESS]	= nft_do_chain_netdev,
	},
};

static int nf_tables_netdev_init_net(struct net *net)
{
	net->nft.netdev = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL);
	if (net->nft.netdev == NULL)
		return -ENOMEM;

	memcpy(net->nft.netdev, &nft_af_netdev, sizeof(nft_af_netdev));

	if (nft_register_afinfo(net, net->nft.netdev) < 0)
		goto err;

	return 0;
err:
	kfree(net->nft.netdev);
	return -ENOMEM;
}

static void nf_tables_netdev_exit_net(struct net *net)
{
	nft_unregister_afinfo(net, net->nft.netdev);
	kfree(net->nft.netdev);
}

static struct pernet_operations nf_tables_netdev_net_ops = {
	.init	= nf_tables_netdev_init_net,
	.exit	= nf_tables_netdev_exit_net,
};

static const struct nf_chain_type nft_filter_chain_netdev = {
	.name		= "filter",
	.type		= NFT_CHAIN_T_DEFAULT,
	.family		= NFPROTO_NETDEV,
	.owner		= THIS_MODULE,
	.hook_mask	= (1 << NF_NETDEV_INGRESS),
};

static void nft_netdev_event(unsigned long event, struct nft_af_info *afi,
			     struct net_device *dev, struct nft_table *table,
			     struct nft_base_chain *basechain)
{
	switch (event) {
	case NETDEV_REGISTER:
		if (strcmp(basechain->dev_name, dev->name) != 0)
			return;

		BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED));

		dev_hold(dev);
		basechain->ops[0].dev = dev;
		basechain->flags &= ~NFT_BASECHAIN_DISABLED;
		if (!(table->flags & NFT_TABLE_F_DORMANT))
			nft_register_basechain(basechain, afi->nops);
		break;
	case NETDEV_UNREGISTER:
		if (strcmp(basechain->dev_name, dev->name) != 0)
			return;

		BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED);

		if (!(table->flags & NFT_TABLE_F_DORMANT))
			nft_unregister_basechain(basechain, afi->nops);

		dev_put(basechain->ops[0].dev);
		basechain->ops[0].dev = NULL;
		basechain->flags |= NFT_BASECHAIN_DISABLED;
		break;
	case NETDEV_CHANGENAME:
		if (dev->ifindex != basechain->ops[0].dev->ifindex)
			return;

		strncpy(basechain->dev_name, dev->name, IFNAMSIZ);
		break;
	}
}

static int nf_tables_netdev_event(struct notifier_block *this,
				  unsigned long event, void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct nft_af_info *afi;
	struct nft_table *table;
	struct nft_chain *chain;

	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) {
		if (afi->family != NFPROTO_NETDEV)
			continue;

		list_for_each_entry(table, &afi->tables, list) {
			list_for_each_entry(chain, &table->chains, list) {
				if (!(chain->flags & NFT_BASE_CHAIN))
					continue;

				nft_netdev_event(event, afi, dev, table,
						 nft_base_chain(chain));
			}
		}
	}
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);

	return NOTIFY_DONE;
}

static struct notifier_block nf_tables_netdev_notifier = {
	.notifier_call	= nf_tables_netdev_event,
};

static int __init nf_tables_netdev_init(void)
{
	int ret;

	nft_register_chain_type(&nft_filter_chain_netdev);
	ret = register_pernet_subsys(&nf_tables_netdev_net_ops);
	if (ret < 0)
		nft_unregister_chain_type(&nft_filter_chain_netdev);

	register_netdevice_notifier(&nf_tables_netdev_notifier);

	return ret;
}

static void __exit nf_tables_netdev_exit(void)
{
	unregister_netdevice_notifier(&nf_tables_netdev_notifier);
	unregister_pernet_subsys(&nf_tables_netdev_net_ops);
	nft_unregister_chain_type(&nft_filter_chain_netdev);
}

module_init(nf_tables_netdev_init);
module_exit(nf_tables_netdev_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_FAMILY(5); /* NFPROTO_NETDEV */
Commit	Line	Data
ed6c4136 PNA	1	/*
	2	* Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/init.h>
	10	#include <linux/module.h>
835b8033	11	#include <linux/netdevice.h>
ed6c4136 PNA	12	#include <net/netfilter/nf_tables.h>
	13	#include <linux/ip.h>
	14	#include <linux/ipv6.h>
	15	#include <net/netfilter/nf_tables_ipv4.h>
	16	#include <net/netfilter/nf_tables_ipv6.h>
	17
	18	static inline void
	19	nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
6aa187f2	20	struct sk_buff *skb,
ed6c4136 PNA	21	const struct nf_hook_state *state)
	22	{
	23	struct iphdr *iph, _iph;
	24	u32 len, thoff;
	25
6aa187f2	26	nft_set_pktinfo(pkt, skb, state);
ed6c4136 PNA	27
	28	iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
	29	&_iph);
	30	if (!iph)
	31	return;
	32
	33	iph = ip_hdr(skb);
	34	if (iph->ihl < 5 \|\| iph->version != 4)
	35	return;
	36
	37	len = ntohs(iph->tot_len);
	38	thoff = iph->ihl * 4;
	39	if (skb->len < len)
	40	return;
	41	else if (len < thoff)
	42	return;
	43
	44	pkt->tprot = iph->protocol;
	45	pkt->xt.thoff = thoff;
	46	pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
	47	}
	48
	49	static inline void
	50	__nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
ed6c4136 PNA	51	struct sk_buff *skb,
	52	const struct nf_hook_state *state)
	53	{
	54	#if IS_ENABLED(CONFIG_IPV6)
	55	struct ipv6hdr *ip6h, _ip6h;
	56	unsigned int thoff = 0;
	57	unsigned short frag_off;
	58	int protohdr;
	59	u32 pkt_len;
	60
	61	ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
	62	&_ip6h);
	63	if (!ip6h)
	64	return;
	65
	66	if (ip6h->version != 6)
	67	return;
	68
	69	pkt_len = ntohs(ip6h->payload_len);
	70	if (pkt_len + sizeof(*ip6h) > skb->len)
	71	return;
	72
	73	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
	74	if (protohdr < 0)
	75	return;
	76
	77	pkt->tprot = protohdr;
	78	pkt->xt.thoff = thoff;
	79	pkt->xt.fragoff = frag_off;
	80	#endif
	81	}
	82
	83	static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
ed6c4136 PNA	84	struct sk_buff *skb,
	85	const struct nf_hook_state *state)
	86	{
6aa187f2 EB	87	nft_set_pktinfo(pkt, skb, state);
6aa187f2 EB	88	__nft_netdev_set_pktinfo_ipv6(pkt, skb, state);
ed6c4136 PNA	89	}
	90
	91	static unsigned int
06198b34	92	nft_do_chain_netdev(void priv, struct sk_buff skb,
ed6c4136 PNA	93	const struct nf_hook_state *state)
	94	{
	95	struct nft_pktinfo pkt;
	96
	97	switch (eth_hdr(skb)->h_proto) {
	98	case htons(ETH_P_IP):
6aa187f2	99	nft_netdev_set_pktinfo_ipv4(&pkt, skb, state);
ed6c4136 PNA	100	break;
ed6c4136 PNA	101	case htons(ETH_P_IPV6):
6aa187f2	102	nft_netdev_set_pktinfo_ipv6(&pkt, skb, state);
ed6c4136 PNA	103	break;
ed6c4136 PNA	104	default:
6aa187f2	105	nft_set_pktinfo(&pkt, skb, state);
ed6c4136 PNA	106	break;
	107	}
	108
06198b34	109	return nft_do_chain(&pkt, priv);
ed6c4136 PNA	110	}
	111
	112	static struct nft_af_info nft_af_netdev __read_mostly = {
	113	.family = NFPROTO_NETDEV,
	114	.nhooks = NF_NETDEV_NUMHOOKS,
	115	.owner = THIS_MODULE,
	116	.flags = NFT_AF_NEEDS_DEV,
	117	.nops = 1,
	118	.hooks = {
	119	[NF_NETDEV_INGRESS] = nft_do_chain_netdev,
	120	},
	121	};
	122
	123	static int nf_tables_netdev_init_net(struct net *net)
	124	{
	125	net->nft.netdev = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL);
	126	if (net->nft.netdev == NULL)
	127	return -ENOMEM;
	128
	129	memcpy(net->nft.netdev, &nft_af_netdev, sizeof(nft_af_netdev));
	130
	131	if (nft_register_afinfo(net, net->nft.netdev) < 0)
	132	goto err;
	133
	134	return 0;
	135	err:
	136	kfree(net->nft.netdev);
	137	return -ENOMEM;
	138	}
	139
	140	static void nf_tables_netdev_exit_net(struct net *net)
	141	{
df05ef87	142	nft_unregister_afinfo(net, net->nft.netdev);
ed6c4136 PNA	143	kfree(net->nft.netdev);
	144	}
	145
	146	static struct pernet_operations nf_tables_netdev_net_ops = {
	147	.init = nf_tables_netdev_init_net,
	148	.exit = nf_tables_netdev_exit_net,
	149	};
	150
	151	static const struct nf_chain_type nft_filter_chain_netdev = {
	152	.name = "filter",
	153	.type = NFT_CHAIN_T_DEFAULT,
	154	.family = NFPROTO_NETDEV,
	155	.owner = THIS_MODULE,
	156	.hook_mask = (1 << NF_NETDEV_INGRESS),
	157	};
	158
835b8033 PNA	159	static void nft_netdev_event(unsigned long event, struct nft_af_info *afi,
	160	struct net_device dev, struct nft_table table,
	161	struct nft_base_chain *basechain)
	162	{
	163	switch (event) {
	164	case NETDEV_REGISTER:
	165	if (strcmp(basechain->dev_name, dev->name) != 0)
	166	return;
	167
	168	BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED));
	169
	170	dev_hold(dev);
	171	basechain->ops[0].dev = dev;
	172	basechain->flags &= ~NFT_BASECHAIN_DISABLED;
	173	if (!(table->flags & NFT_TABLE_F_DORMANT))
	174	nft_register_basechain(basechain, afi->nops);
	175	break;
	176	case NETDEV_UNREGISTER:
	177	if (strcmp(basechain->dev_name, dev->name) != 0)
	178	return;
	179
	180	BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED);
	181
	182	if (!(table->flags & NFT_TABLE_F_DORMANT))
	183	nft_unregister_basechain(basechain, afi->nops);
	184
	185	dev_put(basechain->ops[0].dev);
	186	basechain->ops[0].dev = NULL;
	187	basechain->flags \|= NFT_BASECHAIN_DISABLED;
	188	break;
	189	case NETDEV_CHANGENAME:
	190	if (dev->ifindex != basechain->ops[0].dev->ifindex)
	191	return;
	192
	193	strncpy(basechain->dev_name, dev->name, IFNAMSIZ);
	194	break;
	195	}
	196	}
	197
	198	static int nf_tables_netdev_event(struct notifier_block *this,
	199	unsigned long event, void *ptr)
	200	{
	201	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	202	struct nft_af_info *afi;
	203	struct nft_table *table;
	204	struct nft_chain *chain;
	205
	206	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	207	list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) {
	208	if (afi->family != NFPROTO_NETDEV)
	209	continue;
	210
	211	list_for_each_entry(table, &afi->tables, list) {
	212	list_for_each_entry(chain, &table->chains, list) {
	213	if (!(chain->flags & NFT_BASE_CHAIN))
	214	continue;
	215
	216	nft_netdev_event(event, afi, dev, table,
	217	nft_base_chain(chain));
	218	}
	219	}
	220	}
	221	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
	222
223	return NOTIFY_DONE;
224	}
225
226	static struct notifier_block nf_tables_netdev_notifier = {
227	.notifier_call = nf_tables_netdev_event,
228	};
229
ed6c4136 PNA	230	static int __init nf_tables_netdev_init(void)
	231	{
	232	int ret;
	233
	234	nft_register_chain_type(&nft_filter_chain_netdev);
	235	ret = register_pernet_subsys(&nf_tables_netdev_net_ops);
	236	if (ret < 0)
	237	nft_unregister_chain_type(&nft_filter_chain_netdev);
	238
835b8033 PNA	239	register_netdevice_notifier(&nf_tables_netdev_notifier);
835b8033 PNA	240
ed6c4136 PNA	241	return ret;
	242	}
	243
	244	static void __exit nf_tables_netdev_exit(void)
	245	{
835b8033	246	unregister_netdevice_notifier(&nf_tables_netdev_notifier);
ed6c4136 PNA	247	unregister_pernet_subsys(&nf_tables_netdev_net_ops);
	248	nft_unregister_chain_type(&nft_filter_chain_netdev);
	249	}
	250
	251	module_init(nf_tables_netdev_init);
	252	module_exit(nf_tables_netdev_exit);
	253
	254	MODULE_LICENSE("GPL");
	255	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	256	MODULE_ALIAS_NFT_FAMILY(5); /* NFPROTO_NETDEV */