netfilter: add nf_ipv6_ops hook to fix xt_addrtype with IPv6
Quoting https://bugzilla.netfilter.org/show_bug.cgi?id=812:
[ ip6tables -m addrtype ]
When I tried to use in the nat/PREROUTING it messes up the
routing cache even if the rule didn't matched at all.
[..]
If I remove the --limit-iface-in from the non-working scenario, so just
use the -m addrtype --dst-type LOCAL it works!
This happens when LOCAL type matching is requested with --limit-iface-in,
and the default ipv6 route is via the interface the packet we test
arrived on.
Because xt_addrtype uses ip6_route_output, the ipv6 routing implementation
creates an unwanted cached entry, and the packet won't make it to the
real/expected destination.
Silently ignoring --limit-iface-in makes the routing work but it breaks
rule matching (--dst-type LOCAL with limit-iface-in is supposed to only
match if the dst address is configured on the incoming interface;
without --limit-iface-in it will match if the address is reachable
via lo).
The test should call ipv6_chk_addr() instead. However, this would add
a link-time dependency on ipv6.
There are two possible solutions:
1) Revert the commit that moved ipt_addrtype to xt_addrtype,
and put ipv6 specific code into ip6t_addrtype.
2) add new "nf_ipv6_ops" struct to register pointers to ipv6 functions.
While the former might seem preferable, Pablo pointed out that there
are more xt modules with link-time dependeny issues regarding ipv6,
so lets go for 2).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index d1ab6ab..d1b2d80 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1487,7 +1487,7 @@
}
int ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
- struct net_device *dev, int strict)
+ const struct net_device *dev, int strict)
{
struct inet6_ifaddr *ifp;
unsigned int hash = inet6_addr_hash(addr);
