Teach resolve_my_address() to return a cached answer

I didn't make any of the callers use this feature yet.

1 files changed, 18 insertions, 2 deletions

diff --git a/src/or/config.c b/src/or/config.c
index 7ca20e46b4..e37b148b7d 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -1908,12 +1908,16 @@ static uint32_t last_resolved_addr = 0;
  *     holding that hostname. (If we didn't get our address by resolving a
  *     hostname, set *<b>hostname_out</b> to NULL.)
  *
+ * If <b>use_cached_addr</b> is true, and we have a plausible answer,
+ * provide that answer and return.
+ *
  * XXXX ipv6
  */
 int
 resolve_my_address(int warn_severity, const or_options_t *options,
                    uint32_t *addr_out,
-                   const char **method_out, char **hostname_out)
+                   const char **method_out, char **hostname_out,
+                   int use_cached_addr)
 {
   struct in_addr in;
   uint32_t addr; /* host order */
@@ -1931,6 +1935,18 @@ resolve_my_address(int warn_severity, const or_options_t *options,
   tor_assert(addr_out);
 
   /*
+   * Step zero: if used_cached_addr is true, and we have a cached answer,
+   * just return it and be done.
+   */
+
+  if (use_cached_addr && last_resolved_addr) {
+    *addr_out = last_resolved_addr;
+    if (method_out)
+      *method_out = "CACHED";
+    return 0;
+  }
+
+  /*
    * Step one: Fill in 'hostname' to be our best guess.
    */
 
@@ -2343,7 +2359,7 @@ options_validate(or_options_t *old_options, or_options_t *options,
   if (authdir_mode(options)) {
     /* confirm that our address isn't broken, so we can complain now */
     uint32_t tmp;
-    if (resolve_my_address(LOG_WARN, options, &tmp, NULL, NULL) < 0)
+    if (resolve_my_address(LOG_WARN, options, &tmp, NULL, NULL, 0) < 0)
       REJECT("Failed to resolve/guess local address. See logs for details.");
   }