netfilter: xtables: fix IPv6 dependency in the cluster match This patch fixes a dependency with IPv6: ERROR: "__ipv6_addr_type" [net/netfilter/xt_cluster.ko] undefined! This patch adds a function that checks if the higher bits of the address is 0xFF to identify a multicast address, instead of adding a dependency due to __ipv6_addr_type(). I came up with this idea after Patrick McHardy pointed possible problems with runtime module dependencies. Reported-by: Steven Noonan Reported-by: Randy Dunlap Reported-by: Cyrill Gorcunov Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_cluster.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/net/netfilter/xt_cluster.c b/net/netfilter/xt_cluster.c index ad5bd89..f2d2482 100644 --- a/net/netfilter/xt_cluster.c +++ b/net/netfilter/xt_cluster.c @@ -58,6 +58,13 @@ xt_cluster_hash(const struct nf_conn *ct, } static inline bool +xt_cluster_ipv6_is_multicast(const struct in6_addr *addr) +{ + __be32 st = addr->s6_addr32[0]; + return ((st & htonl(0xFF000000)) == htonl(0xFF000000)); +} + +static inline bool xt_cluster_is_multicast_addr(const struct sk_buff *skb, u_int8_t family) { bool is_multicast = false; @@ -67,8 +74,8 @@ xt_cluster_is_multicast_addr(const struct sk_buff *skb, u_int8_t family) is_multicast = ipv4_is_multicast(ip_hdr(skb)->daddr); break; case NFPROTO_IPV6: - is_multicast = ipv6_addr_type(&ipv6_hdr(skb)->daddr) & - IPV6_ADDR_MULTICAST; + is_multicast = + xt_cluster_ipv6_is_multicast(&ipv6_hdr(skb)->daddr); break; default: WARN_ON(1);