src: Add import command for low level json

This new operation allows to import low level virtual machine ruleset in
json to make incremental changes using the parse functions of libnftnl.

A basic way to test this new functionality is:

 $ cat file.json | nft import vm json

where the file.json is a ruleset exported in low level json format.

To export json rules in low level virtual machine format
we need to specify "vm" token before json. See below
        $ nft export vm json

and
        $ nft export/import json

will do no operations.
Same goes with  "$nft monitor"

Highly based on work from  Alvaro Neira <alvaroneay@gmail.com>
and Arturo Borrero <arturo@netfilter.org>

Acked-by: Arturo Borrero Gonzalez <arturo@netfilter.org>
Signed-off-by: Shyam Saini <mayhs11saini@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/netlink.h b/include/netlink.h
index 4ec215da..0d71a6b9 100644
--- a/include/netlink.h
+++ b/include/netlink.h
@@ -227,4 +227,13 @@ bool netlink_batch_supported(struct mnl_socket *nf_sock, uint32_t *seqnum);
 
 int netlink_echo_callback(const struct nlmsghdr *nlh, void *data);
 
+struct ruleset_parse {
+	struct netlink_ctx      *nl_ctx;
+	struct cmd              *cmd;
+};
+
+struct nftnl_parse_ctx;
+
+int netlink_markup_parse_cb(const struct nftnl_parse_ctx *ctx);
+
 #endif /* NFTABLES_NETLINK_H */