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netfilter: xt_addrtype: ipv6 support

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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: Florian Westphal <fwestphal@astaro.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Florian Westphal 2011-03-15 20:17:44 +01:00 committed by Patrick McHardy
parent de81bbea17
commit 2f5dc63123
3 changed files with 114 additions and 2 deletions
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17
include/linux/netfilter/xt_addrtype.h
View file

@ -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 */

1
net/netfilter/Kconfig
View file

@ -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, ...

98
net/netfilter/xt_addrtype.c
View file

@ -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,