From 28a2260812ec9f9416524634453f8ff306411417 Mon Sep 17 00:00:00 2001
From: Brad House <brad@brad-house.com>
Date: Fri, 13 Sep 2024 15:37:44 -0400
Subject: [PATCH] ares_get_servers_csv() output in uri format when needed

---
 src/lib/ares_update_servers.c | 71 ++++++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

diff --git a/src/lib/ares_update_servers.c b/src/lib/ares_update_servers.c
index 2a04ac2411..43f841860b 100644
--- a/src/lib/ares_update_servers.c
+++ b/src/lib/ares_update_servers.c
@@ -228,7 +228,7 @@ static ares_status_t parse_nameserver_uri(ares_buf_t *buf, ares_sconfig_t *sconf
   sconfig->tcp_port = sconfig->udp_port;
   port = ares_uri_get_query_key(uri, "tcpport");
   if (port != NULL) {
-    sconfig->tcp_port = atoi(port);
+    sconfig->tcp_port = (unsigned short)atoi(port);
   }
 
 done:
@@ -963,12 +963,81 @@ ares_status_t ares_in_addr_to_sconfig_llist(const struct in_addr *servers,
   /* LCOV_EXCL_STOP */
 }
 
+static ares_bool_t ares_server_use_uri(const ares_server_t *server)
+{
+  /* Currently only reason to use new format is if the ports for udp and tcp
+   * are different */
+  if (server->tcp_port != server->udp_port) {
+    return ARES_TRUE;
+  }
+  return ARES_FALSE;
+}
+
+static ares_status_t ares_get_server_addr_uri(const ares_server_t *server, ares_buf_t *buf)
+{
+  ares_uri_t   *uri = NULL;
+  ares_status_t status;
+  char          addr[INET6_ADDRSTRLEN];
+
+  uri = ares_uri_create();
+  if (uri == NULL) {
+    return ARES_ENOMEM;
+  }
+
+  status = ares_uri_set_scheme(uri, "dns");
+  if (status != ARES_SUCCESS) {
+    goto done;
+  }
+
+  ares_inet_ntop(server->addr.family, &server->addr.addr, addr, sizeof(addr));
+
+  if (ares_strlen(server->ll_iface)) {
+    char addr_iface[INET6_ADDRSTRLEN + 17];
+
+    snprintf(addr_iface, sizeof(addr_iface), "%s%%%s", addr, server->ll_iface);
+    status = ares_uri_set_host(uri, addr_iface);
+  } else {
+    status = ares_uri_set_host(uri, addr);
+  }
+
+  if (status != ARES_SUCCESS) {
+    goto done;
+  }
+
+  status = ares_uri_set_port(uri, server->udp_port);
+  if (status != ARES_SUCCESS) {
+    goto done;
+  }
+
+  if (server->udp_port != server->tcp_port) {
+    char port[6];
+    snprintf(port, sizeof(port), "%d", server->tcp_port);
+    status = ares_uri_set_query_key(uri, "tcpport", port);
+    if (status != ARES_SUCCESS) {
+      goto done;
+    }
+  }
+
+  status = ares_uri_write_buf(uri, buf);
+  if (status != ARES_SUCCESS) {
+    goto done;
+  }
+
+done:
+  ares_uri_destroy(uri);
+  return status;
+}
+
 /* Write out the details of a server to a buffer */
 ares_status_t ares_get_server_addr(const ares_server_t *server, ares_buf_t *buf)
 {
   ares_status_t status;
   char          addr[INET6_ADDRSTRLEN];
 
+  if (ares_server_use_uri(server)) {
+    return ares_get_server_addr_uri(server, buf);
+  }
+
   /* ipv4addr or [ipv6addr] */
   if (server->addr.family == AF_INET6) {
     status = ares_buf_append_byte(buf, '[');