[PATCH v2] extensions: libip6t_REJECT: Add translation to nft

[Shivani Bhardwaj <shivanib134@gmail.com>]

Add translation for target REJECT to nftables.

Examples:

$ sudo ip6tables-translate -A FORWARD -p TCP --dport 22 -j REJECT --reject-with icmp6-reject-route
nft add rule ip6 filter FORWARD tcp dport 22 counter reject with icmpv6 type reject-route

$ sudo ip6tables-translate -A FORWARD -p TCP --dport 22 -j REJECT --reject-with tcp-reset
nft add rule ip6 filter FORWARD tcp dport 22 counter reject with tcp reset

Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
---
Changes in v2:
	Remove unnecessary if endif block

 extensions/libip6t_REJECT.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/extensions/libip6t_REJECT.c b/extensions/libip6t_REJECT.c
index d62f431..3b8431c 100644
--- a/extensions/libip6t_REJECT.c
+++ b/extensions/libip6t_REJECT.c
@@ -17,6 +17,11 @@ struct reject_names {
 	const char *desc;
 };
 
+struct reject_names_xlate {
+	const char *name;
+	enum ip6t_reject_with with;
+};
+
 enum {
 	O_REJECT_WITH = 0,
 };
@@ -124,6 +129,35 @@ static void REJECT_save(const void *ip, const struct xt_entry_target *target)
 	printf(" --reject-with %s", reject_table[i].name);
 }
 
+static const struct reject_names_xlate reject_table_xlate[] = {
+	{"no-route",		IP6T_ICMP6_NO_ROUTE},
+	{"admin-prohibited",	IP6T_ICMP6_ADM_PROHIBITED},
+	{"addr-unreachable",	IP6T_ICMP6_ADDR_UNREACH},
+	{"port-unreachable",	IP6T_ICMP6_PORT_UNREACH},
+	{"tcp reset",		IP6T_TCP_RESET},
+	{"policy-fail",		IP6T_ICMP6_POLICY_FAIL},
+	{"reject-route",	IP6T_ICMP6_REJECT_ROUTE}
+};
+
+static int REJECT_xlate(const struct xt_entry_target *target,
+			struct xt_buf *buf, int numeric)
+{
+	const struct ip6t_reject_info *reject =
+				(const struct ip6t_reject_info *)target->data;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(reject_table_xlate); ++i)
+		if (reject_table_xlate[i].with == reject->with)
+			break;
+	if (reject->with == IP6T_TCP_RESET)
+		xt_buf_add(buf, "reject with %s", reject_table_xlate[i].name);
+	else
+		xt_buf_add(buf, "reject with icmpv6 type %s",
+			   reject_table_xlate[i].name);
+
+	return 1;
+}
+
 static struct xtables_target reject_tg6_reg = {
 	.name = "REJECT",
 	.version	= XTABLES_VERSION,
@@ -136,6 +170,7 @@ static struct xtables_target reject_tg6_reg = {
 	.save		= REJECT_save,
 	.x6_parse	= REJECT_parse,
 	.x6_options	= REJECT_opts,
+	.xlate		= REJECT_xlate,
 };
 
 void _init(void)
-- 
1.9.1