odhcpd: supports rewrite DNS server to local IPv6 DNS server in relay mode

Signed-off-by: Liangbin Lian <jjm2473@gmail.com>

Author: jjm2473

src/dhcpv6.c

@@ -885,7 +885,7 @@ static void relay_server_response(uint8_t *data, size_t len)
 	}
 
 	/* Rewrite DNS servers if requested */
-	if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
+	if ((iface->always_rewrite_dns || iface->dns_service) && dns_ptr && dns_count > 0) {
 		if (is_authenticated)
 			return; /* Impossible to rewrite */
 

src/router.c

@@ -1240,7 +1240,7 @@ static void forward_router_advertisement(const struct interface *iface, uint8_t
 		}
 
 		/* If we have to rewrite DNS entries */
-		if (c->always_rewrite_dns && dns_ptr && dns_count > 0) {
+		if ((c->always_rewrite_dns || c->dns_service) && dns_ptr && dns_count > 0) {
 			const struct in6_addr *rewrite = c->dns;
 			struct in6_addr addr;
 			size_t rewrite_cnt = c->dns_cnt;