src: NAT support for intervals in maps

This patch allows you to specify an interval of IP address in maps.

 table ip x {
        chain y {
                type nat hook postrouting priority srcnat; policy accept;
                snat ip interval to ip saddr map { 10.141.11.4 : 192.168.2.2-192.168.2.4 }
        }
 }

The example above performs SNAT to packets that comes from 10.141.11.4
to an interval of IP addresses from 192.168.2.2 to 192.168.2.4 (both
included).

You can also combine this with dynamic maps:

 table ip x {
        map y {
                type ipv4_addr : interval ipv4_addr
                flags interval
                elements = { 10.141.10.0/24 : 192.168.2.2-192.168.2.4 }
        }

        chain y {
                type nat hook postrouting priority srcnat; policy accept;
                snat ip interval to ip saddr map @y
        }
 }

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

1 files changed, 5 insertions, 0 deletions

diff --git a/include/statement.h b/include/statement.h
index 8fb459ca..8427f47e 100644
--- a/include/statement.h
+++ b/include/statement.h
@@ -119,6 +119,10 @@ enum nft_nat_etypes {
 
 extern const char *nat_etype2str(enum nft_nat_etypes type);
 
+enum {
+	STMT_NAT_F_INTERVAL	= (1 << 0),
+};
+
 struct nat_stmt {
 	enum nft_nat_etypes	type;
 	struct expr		*addr;
@@ -126,6 +130,7 @@ struct nat_stmt {
 	uint32_t		flags;
 	uint8_t			family;
 	bool			ipportmap;
+	uint32_t		type_flags;
 };
 
 extern struct stmt *nat_stmt_alloc(const struct location *loc,