fix: resolve_bootstrap_node() not checking net_getipport() returned count correctly

doc: improve inline docu of return of net_getipport

Author: Green-Sky

other/bootstrap_daemon/docker/tox-bootstrapd.sha256

@@ -1 +1 @@
-1fadb7de1ccf46186e33c13343e2c67f4c84e78fadfbfbbc8f3ce70e670907f2  /usr/local/bin/tox-bootstrapd
+3d28c914487efaae4336af17b221049c73249fb917d672f5ae6d9c092522a24f  /usr/local/bin/tox-bootstrapd

toxcore/network.h

@@ -544,8 +544,9 @@ bool net_connect(const Logger *log, Socket sock, const IP_Port *ip_port);
  * Skip all addresses with socktype != type (use type = -1 to get all addresses)
  * To correctly deallocate array memory use `net_freeipport()`
  *
- * return number of elements in res array
- * and -1 on error.
+ * @return number of elements in res array.
+ * @retval 0 if res array empty.
+ * @retval -1 on error.
  */
 non_null()
 int32_t net_getipport(const char *node, IP_Port **res, int tox_type);

toxcore/tox.c

@@ -1008,7 +1008,7 @@ static int32_t resolve_bootstrap_node(Tox *tox, const char *host, uint16_t port,
 
     const int32_t count = net_getipport(host, root, TOX_SOCK_DGRAM);
 
-    if (count == -1) {
+    if (count < 1) {
         LOGGER_DEBUG(tox->m->log, "could not resolve bootstrap node '%s'", host);
         net_freeipport(*root);
         SET_ERROR_PARAMETER(error, TOX_ERR_BOOTSTRAP_BAD_HOST);