xtables: add IPv6 support

Summary of changes to add IPv6 support to the xtables utility:

* modify all commands (add, delete, replace, check and listing) to
  support IPv6 addresses.

And for the internal nft library:

* add family to struct nft_handle and modify all caller to use this
  family instead of the hardcoded AF_INET.
* move code that we can re-use for IPv4 and IPv6 into helper functions.
* add IPv6 rule printing support.
* add support to parse IPv6 address.

Pablo added several improvements to this patch:

* added basic xtables-save and xtables-restore support (so it defaults
  to IPv4)
* fixed a couple of bugs found while testing
* added reference when -f is used to point to -m frag (until we can make
  this consistent with IPv4).

Note that we use one single xtables binary utility for IPv4 and IPv6.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/iptables/xtables-restore.c b/iptables/xtables-restore.c
index 30ea813c..e83eacc3 100644
--- a/iptables/xtables-restore.c
+++ b/iptables/xtables-restore.c
@@ -161,7 +161,9 @@ static void add_param_to_argv(char *parsestart)
 int
 xtables_restore_main(int argc, char *argv[])
 {
-	struct nft_handle h;
+	struct nft_handle h = {
+		.family = AF_INET,	/* default to IPv4 */
+	};
 	char buffer[10240];
 	int c;
 	char curtable[XT_TABLE_MAXNAMELEN + 1];