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, 1 insertions, 0 deletions

diff --git a/iptables/nft.h b/iptables/nft.h
index aed2498b..1bd9ccce 100644
--- a/iptables/nft.h
+++ b/iptables/nft.h
@@ -4,6 +4,7 @@
 #include "xshared.h"
 
 struct nft_handle {
+	int			family;
 	struct mnl_socket	*nl;
 	uint32_t		portid;
 	uint32_t		seq;