Commit 2f5dc631 authored by Florian Westphal's avatar Florian Westphal Committed by Patrick McHardy
Browse files

netfilter: xt_addrtype: ipv6 support 



The kernel will refuse certain types that do not work in ipv6 mode.
We can then add these features incrementally without risk of userspace
breakage.

Signed-off-by: default avatarFlorian Westphal <fwestphal@astaro.com>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
parent de81bbea

include/linux/netfilter/xt_addrtype.h

+17 −0
Original line number Diff line number Diff line
@@ -10,6 +10,23 @@ enum { 
	XT_ADDRTYPE_LIMIT_IFACE_OUT	= 0x0008,

};





/* rtn_type enum values from rtnetlink.h, but shifted */

enum {

	XT_ADDRTYPE_UNSPEC = 1 << 0,

	XT_ADDRTYPE_UNICAST = 1 << 1,	/* 1 << RTN_UNICAST */

	XT_ADDRTYPE_LOCAL  = 1 << 2,	/* 1 << RTN_LOCAL, etc */

	XT_ADDRTYPE_BROADCAST = 1 << 3,

	XT_ADDRTYPE_ANYCAST = 1 << 4,

	XT_ADDRTYPE_MULTICAST = 1 << 5,

	XT_ADDRTYPE_BLACKHOLE = 1 << 6,

	XT_ADDRTYPE_UNREACHABLE = 1 << 7,

	XT_ADDRTYPE_PROHIBIT = 1 << 8,

	XT_ADDRTYPE_THROW = 1 << 9,

	XT_ADDRTYPE_NAT = 1 << 10,

	XT_ADDRTYPE_XRESOLVE = 1 << 11,

};



struct xt_addrtype_info_v1 {

	__u16	source;		/* source-type mask */

	__u16	dest;		/* dest-type mask */

net/netfilter/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -652,6 +652,7 @@ comment "Xtables matches" 
config NETFILTER_XT_MATCH_ADDRTYPE

	tristate '"addrtype" address type match support'

	depends on NETFILTER_ADVANCED

	depends on (IPV6 || IPV6=n)

	---help---

	  This option allows you to match what routing thinks of an address,

	  eg. UNICAST, LOCAL, BROADCAST, ...

net/netfilter/xt_addrtype.c

+96 −2
Original line number Diff line number Diff line
@@ -16,6 +16,12 @@ 
#include <linux/ip.h>

#include <net/route.h>



#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)

#include <net/ipv6.h>

#include <net/ip6_route.h>

#include <net/ip6_fib.h>

#endif



#include <linux/netfilter/xt_addrtype.h>

#include <linux/netfilter/x_tables.h>
@@ -23,6 +29,73 @@ MODULE_LICENSE("GPL"); 
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");

MODULE_DESCRIPTION("Xtables: address type match");

MODULE_ALIAS("ipt_addrtype");

MODULE_ALIAS("ip6t_addrtype");



#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)

static u32 xt_addrtype_rt6_to_type(const struct rt6_info *rt)

{

	u32 ret;



	if (!rt)

		return XT_ADDRTYPE_UNREACHABLE;



	if (rt->rt6i_flags & RTF_REJECT)

		ret = XT_ADDRTYPE_UNREACHABLE;

	else

		ret = 0;



	if (rt->rt6i_flags & RTF_LOCAL)

		ret |= XT_ADDRTYPE_LOCAL;

	if (rt->rt6i_flags & RTF_ANYCAST)

		ret |= XT_ADDRTYPE_ANYCAST;

	return ret;

}



static bool match_type6(struct net *net, const struct net_device *dev,

				const struct in6_addr *addr, u16 mask)

{

	int addr_type = ipv6_addr_type(addr);



	if ((mask & XT_ADDRTYPE_MULTICAST) &&

	    !(addr_type & IPV6_ADDR_MULTICAST))

		return false;

	if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST))

		return false;

	if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY)

		return false;



	if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST |

	     XT_ADDRTYPE_UNREACHABLE) & mask) {

		struct rt6_info *rt;

		u32 type;

		int ifindex = dev ? dev->ifindex : 0;



		rt = rt6_lookup(net, addr, NULL, ifindex, !!dev);



		type = xt_addrtype_rt6_to_type(rt);



		dst_release(&rt->dst);

		return !!(mask & type);

	}

	return true;

}



static bool

addrtype_mt6(struct net *net, const struct net_device *dev,

	const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info)

{

	const struct ipv6hdr *iph = ipv6_hdr(skb);

	bool ret = true;



	if (info->source)

		ret &= match_type6(net, dev, &iph->saddr, info->source) ^

		       (info->flags & XT_ADDRTYPE_INVERT_SOURCE);

	if (ret && info->dest)

		ret &= match_type6(net, dev, &iph->daddr, info->dest) ^

		       !!(info->flags & XT_ADDRTYPE_INVERT_DEST);

	return ret;

}

#endif



static inline bool match_type(struct net *net, const struct net_device *dev,

			      __be32 addr, u_int16_t mask)
@@ -53,7 +126,7 @@ addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) 
{

	struct net *net = dev_net(par->in ? par->in : par->out);

	const struct xt_addrtype_info_v1 *info = par->matchinfo;

	const struct iphdr *iph = ip_hdr(skb);

	const struct iphdr *iph;

	const struct net_device *dev = NULL;

	bool ret = true;
@@ -62,6 +135,11 @@ addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) 
	else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT)

		dev = par->out;



#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)

	if (par->family == NFPROTO_IPV6)

		return addrtype_mt6(net, dev, skb, info);

#endif

	iph = ip_hdr(skb);

	if (info->source)

		ret &= match_type(net, dev, iph->saddr, info->source) ^

		       (info->flags & XT_ADDRTYPE_INVERT_SOURCE);
@@ -98,6 +176,22 @@ static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par) 
		return -EINVAL;

	}



#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)

	if (par->family == NFPROTO_IPV6) {

		if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) {

			pr_err("ipv6 BLACKHOLE matching not supported\n");

			return -EINVAL;

		}

		if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) {

			pr_err("ipv6 PROHIBT (THROW, NAT ..) matching not supported\n");

			return -EINVAL;

		}

		if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) {

			pr_err("ipv6 does not support BROADCAST matching\n");

			return -EINVAL;

		}

	}

#endif

	return 0;

}
@@ -111,7 +205,7 @@ static struct xt_match addrtype_mt_reg[] __read_mostly = { 
	},

	{

		.name		= "addrtype",

		.family		= NFPROTO_IPV4,

		.family		= NFPROTO_UNSPEC,

		.revision	= 1,

		.match		= addrtype_mt_v1,

		.checkentry	= addrtype_mt_checkentry_v1,