extensions: ipt_DNAT: Combine xlate functions also

Make use of the new sprint_range() to introduce a common inner function
for both v1 and v2 xlate functions.

Also abort translation with shifted port ranges to not hide the missing
feature in nftables.

Signed-off-by: Phil Sutter <phil@nwl.cc>

1 files changed, 21 insertions, 67 deletions

diff --git a/extensions/libipt_DNAT.c b/extensions/libipt_DNAT.c
index b72437d5..9a179919 100644
--- a/extensions/libipt_DNAT.c
+++ b/extensions/libipt_DNAT.c
@@ -266,47 +266,36 @@ static void DNAT_save(const void *ip, const struct xt_entry_target *target)
 	__DNAT_print(&range, true);
 }
 
-static void print_range_xlate(const struct nf_nat_ipv4_range *r,
-			struct xt_xlate *xl)
+static int __DNAT_xlate(struct xt_xlate *xl, const struct nf_nat_range2 *r)
 {
-	if (r->flags & NF_NAT_RANGE_MAP_IPS) {
-		struct in_addr a;
+	char *range_str = sprint_range(r);
+	const char *sep = " ";
 
-		a.s_addr = r->min_ip;
-		xt_xlate_add(xl, "%s", xtables_ipaddr_to_numeric(&a));
-		if (r->max_ip != r->min_ip) {
-			a.s_addr = r->max_ip;
-			xt_xlate_add(xl, "-%s", xtables_ipaddr_to_numeric(&a));
-		}
+	/* shifted portmap ranges are not supported by nftables */
+	if (r->flags & NF_NAT_RANGE_PROTO_OFFSET)
+		return 0;
+
+	xt_xlate_add(xl, "dnat");
+	if (strlen(range_str))
+		xt_xlate_add(xl, " to %s", range_str);
+	if (r->flags & NF_NAT_RANGE_PROTO_RANDOM) {
+		xt_xlate_add(xl, "%srandom", sep);
+		sep = ",";
 	}
-	if (r->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
-		xt_xlate_add(xl, ":%hu", ntohs(r->min.tcp.port));
-		if (r->max.tcp.port != r->min.tcp.port)
-			xt_xlate_add(xl, "-%hu", ntohs(r->max.tcp.port));
+	if (r->flags & NF_NAT_RANGE_PERSISTENT) {
+		xt_xlate_add(xl, "%spersistent", sep);
+		sep = ",";
 	}
+	return 1;
 }
 
 static int DNAT_xlate(struct xt_xlate *xl,
 		      const struct xt_xlate_tg_params *params)
 {
-	const struct nf_nat_ipv4_multi_range_compat *mr =
-			(const void *)params->target->data;
-	bool sep_need = false;
-	const char *sep = " ";
-
-	xt_xlate_add(xl, "dnat to ");
-	print_range_xlate(mr->range, xl);
-	if (mr->range->flags & NF_NAT_RANGE_PROTO_RANDOM) {
-		xt_xlate_add(xl, " random");
-		sep_need = true;
-	}
-	if (mr->range->flags & NF_NAT_RANGE_PERSISTENT) {
-		if (sep_need)
-			sep = ",";
-		xt_xlate_add(xl, "%spersistent", sep);
-	}
+	struct nf_nat_range2 range =
+		RANGE2_INIT_FROM_IPV4_MRC(params->target->data);
 
-	return 1;
+	return __DNAT_xlate(xl, &range);
 }
 
 static void DNAT_parse_v2(struct xt_option_call *cb)
@@ -336,45 +325,10 @@ static void DNAT_save_v2(const void *ip, const struct xt_entry_target *target)
 	__DNAT_print((const void *)target->data, true);
 }
 
-static void print_range_xlate_v2(const struct nf_nat_range2 *range,
-			      struct xt_xlate *xl)
-{
-	if (range->flags & NF_NAT_RANGE_MAP_IPS) {
-		xt_xlate_add(xl, "%s", xtables_ipaddr_to_numeric(&range->min_addr.in));
-		if (memcmp(&range->min_addr, &range->max_addr,
-			   sizeof(range->min_addr))) {
-			xt_xlate_add(xl, "-%s", xtables_ipaddr_to_numeric(&range->max_addr.in));
-		}
-	}
-	if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
-		xt_xlate_add(xl, ":%hu", ntohs(range->min_proto.tcp.port));
-		if (range->max_proto.tcp.port != range->min_proto.tcp.port)
-			xt_xlate_add(xl, "-%hu", ntohs(range->max_proto.tcp.port));
-		if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
-			xt_xlate_add(xl, ";%hu", ntohs(range->base_proto.tcp.port));
-	}
-}
-
 static int DNAT_xlate_v2(struct xt_xlate *xl,
 		      const struct xt_xlate_tg_params *params)
 {
-	const struct nf_nat_range2 *range = (const void *)params->target->data;
-	bool sep_need = false;
-	const char *sep = " ";
-
-	xt_xlate_add(xl, "dnat to ");
-	print_range_xlate_v2(range, xl);
-	if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) {
-		xt_xlate_add(xl, " random");
-		sep_need = true;
-	}
-	if (range->flags & NF_NAT_RANGE_PERSISTENT) {
-		if (sep_need)
-			sep = ",";
-		xt_xlate_add(xl, "%spersistent", sep);
-	}
-
-	return 1;
+	return __DNAT_xlate(xl, (const void *)params->target->data);
 }
 
 static struct xtables_target dnat_tg_reg[] = {