netfilter: xt_addrtype: ipv6 support
Florian Westphal [Tue, 15 Mar 2011 19:17:44 +0000 (20:17 +0100)]
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>

include/linux/netfilter/xt_addrtype.h
net/netfilter/Kconfig
net/netfilter/xt_addrtype.c

index b492fc8..b156baa 100644 (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 */
index 32bff6d..c3f988a 100644 (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, ...
index e89c0b8..2220b85 100644 (file)
 #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,