[PATCH] extensions: libip6t_REDIRECT: Add translation to nft

[Shivani Bhardwaj <shivanib134@gmail.com>]

Add translation for REDIRECT target to nftables.

Examples:

$ sudo ip6tables-translate -t nat -A prerouting -p tcp --dport 80 -j REDIRECT --to-ports 8080
nft add rule ip6 nat prerouting tcp dport 80 counter redirect to 8080

$ sudo ip6tables-translate -t nat -A prerouting -p tcp --dport 80 -j REDIRECT --to-ports 8080 --random
nft add rule ip6 nat prerouting tcp dport 80 counter redirect to 8080 random

Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
---
 extensions/libip6t_REDIRECT.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/extensions/libip6t_REDIRECT.c b/extensions/libip6t_REDIRECT.c
index 1724aa6..d907d94 100644
--- a/extensions/libip6t_REDIRECT.c
+++ b/extensions/libip6t_REDIRECT.c
@@ -132,6 +132,24 @@ static void REDIRECT_save(const void *ip, const struct xt_entry_target *target)
 	}
 }
 
+static int REDIRECT_xlate(const struct xt_entry_target *target,
+			  struct xt_buf *buf, int numeric)
+{
+	const struct nf_nat_range *range = (const void *)target->data;
+
+	if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+		xt_buf_add(buf, "redirect to %hu",
+			   ntohs(range->min_proto.tcp.port));
+		if (range->max_proto.tcp.port != range->min_proto.tcp.port)
+			xt_buf_add(buf, "-%hu ",
+				   ntohs(range->max_proto.tcp.port));
+		if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
+			xt_buf_add(buf, " random ");
+	}
+
+	return 1;
+}
+
 static struct xtables_target redirect_tg_reg = {
 	.name		= "REDIRECT",
 	.version	= XTABLES_VERSION,
@@ -143,6 +161,7 @@ static struct xtables_target redirect_tg_reg = {
 	.print		= REDIRECT_print,
 	.save		= REDIRECT_save,
 	.x6_options	= REDIRECT_opts,
+	.xlate		= REDIRECT_xlate,
 };
 
 void _init(void)
-- 
1.9.1