Prop210: Add want_authority to directory_get_from_dirserver

src/or/directory.c

@@ -425,14 +425,17 @@ directory_pick_generic_dirserver(dirinfo_type_t type, int pds_flags,
  * Use <b>pds_flags</b> as arguments to router_pick_directory_server()
  * or router_pick_trusteddirserver().
  */
-MOCK_IMPL(void, directory_get_from_dirserver, (uint8_t dir_purpose,
-                                               uint8_t router_purpose,
-                                               const char *resource,
-                                               int pds_flags))
+MOCK_IMPL(void, directory_get_from_dirserver, (
+                            uint8_t dir_purpose,
+                            uint8_t router_purpose,
+                            const char *resource,
+                            int pds_flags,
+                            download_want_authority_t want_authority))
 {
   const routerstatus_t *rs = NULL;
   const or_options_t *options = get_options();
-  int prefer_authority = directory_fetches_from_authorities(options);
+  int prefer_authority = (directory_fetches_from_authorities(options)
+                          || want_authority == DL_WANT_AUTHORITY);
   int require_authority = 0;
   int get_via_tor = purpose_needs_anonymity(dir_purpose, router_purpose);
   dirinfo_type_t type = dir_fetch_type(dir_purpose, router_purpose, resource);

src/or/directory.h

@@ -16,10 +16,12 @@ int directories_have_accepted_server_descriptor(void);
 void directory_post_to_dirservers(uint8_t dir_purpose, uint8_t router_purpose,
                                   dirinfo_type_t type, const char *payload,
                                   size_t payload_len, size_t extrainfo_len);
-MOCK_DECL(void, directory_get_from_dirserver, (uint8_t dir_purpose,
-                                               uint8_t router_purpose,
-                                               const char *resource,
-                                               int pds_flags));
+MOCK_DECL(void, directory_get_from_dirserver, (
+                          uint8_t dir_purpose,
+                          uint8_t router_purpose,
+                          const char *resource,
+                          int pds_flags,
+                          download_want_authority_t want_authority));
 void directory_get_from_all_authorities(uint8_t dir_purpose,
                                         uint8_t router_purpose,
                                         const char *resource);

src/or/entrynodes.c

@@ -2205,7 +2205,7 @@ fetch_bridge_descriptors(const or_options_t *options, time_t now)
         log_info(LD_DIR, "Fetching bridge info '%s' from bridge authority.",
                  resource);
         directory_get_from_dirserver(DIR_PURPOSE_FETCH_SERVERDESC,
-                ROUTER_PURPOSE_BRIDGE, resource, 0);
+                ROUTER_PURPOSE_BRIDGE, resource, 0, DL_WANT_AUTHORITY);
       }
     }
   SMARTLIST_FOREACH_END(bridge);

src/or/or.h

@@ -1955,6 +1955,15 @@ typedef enum {
 } download_schedule_t;
 #define download_schedule_bitfield_t ENUM_BF(download_schedule_t)
 
+/** Enumeration: do we want to try an authority or a fallback directory
+ * mirror for our download? */
+typedef enum {
+  DL_WANT_FALLBACK = 0,
+  DL_WANT_AUTHORITY = 1,
+} download_want_authority_t;
+#define download_want_authority_bitfield_t \
+                                        ENUM_BF(download_want_authority_t)
+
 /** Information about our plans for retrying downloads for a downloadable
  * object. */
 typedef struct download_status_t {

src/or/routerlist.c

@@ -897,8 +897,10 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now)
 
     if (smartlist_len(fps) > 1) {
       resource = smartlist_join_strings(fps, "", 0, NULL);
+      /* XXX - do we want certs from authorities or mirrors? - teor */
       directory_get_from_dirserver(DIR_PURPOSE_FETCH_CERTIFICATE, 0,
-                                   resource, PDS_RETRY_IF_NO_SERVERS);
+                                   resource, PDS_RETRY_IF_NO_SERVERS,
+                                   DL_WANT_FALLBACK);
       tor_free(resource);
     }
     /* else we didn't add any: they were all pending */
@@ -941,8 +943,10 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now)
 
     if (smartlist_len(fp_pairs) > 1) {
       resource = smartlist_join_strings(fp_pairs, "", 0, NULL);
+      /* XXX - do we want certs from authorities or mirrors? - teor */
       directory_get_from_dirserver(DIR_PURPOSE_FETCH_CERTIFICATE, 0,
-                                   resource, PDS_RETRY_IF_NO_SERVERS);
+                                   resource, PDS_RETRY_IF_NO_SERVERS,
+                                   DL_WANT_FALLBACK);
       tor_free(resource);
     }
     /* else they were all pending */
@@ -4383,7 +4387,7 @@ MOCK_IMPL(STATIC void, initiate_descriptor_downloads,
                                             resource, NULL, 0, 0);
   } else {
     directory_get_from_dirserver(purpose, ROUTER_PURPOSE_GENERAL, resource,
-                                 pds_flags);
+                                 pds_flags, DL_WANT_FALLBACK);
   }
   tor_free(resource);
 }
@@ -4667,7 +4671,7 @@ launch_dummy_descriptor_download_as_needed(time_t now,
     last_dummy_download = now;
     directory_get_from_dirserver(DIR_PURPOSE_FETCH_SERVERDESC,
                                  ROUTER_PURPOSE_GENERAL, "authority.z",
-                                 PDS_RETRY_IF_NO_SERVERS);
+                                 PDS_RETRY_IF_NO_SERVERS, DL_WANT_FALLBACK);
   }
 }
 

src/test/test_routerlist.c

@@ -12,11 +12,13 @@ static char output[4*BASE64_DIGEST256_LEN+3+2+2+1];
 
 static void
 mock_get_from_dirserver(uint8_t dir_purpose, uint8_t router_purpose,
-                             const char *resource, int pds_flags)
+                        const char *resource, int pds_flags,
+                        download_want_authority_t want_authority)
 {
   (void)dir_purpose;
   (void)router_purpose;
   (void)pds_flags;
+  (void)want_authority;
   tt_assert(resource);
   strlcpy(output, resource, sizeof(output));
  done: