xtables: add -I chain rulenum

This patch adds the nft_rule_insert function, which allows
us to insert rules at a given position.

The function nft_rule_add has been renamed to nft_rule_append.

This is possible thanks to Eric Leblond's (netfilter: nf_tables:
add insert operation) kernel patch.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
3 files changed