Implement new directory logic: download by descriptor digest, not by key digest. Caches try to download all listed digests from authorities; clients try to download "best" digests from caches.

svn:r5659

doc/TODO

@@ -46,39 +46,42 @@ N - Destroy and truncated cells should have reasons.
     - Specify
     - Implement
 
-N - Only use a routerdesc if you recognize its hash.
+N . Only use a routerdesc if you recognize its hash.
     o (Must defer till dirservers are upgraded to latest code, which
       actually generates these hashes.)
-    - Of course, authdirservers must not do this.
+    . Of course, authdirservers must not do this.
     o If we have a routerdesc for Bob, and he says, "I'm 0.1.0.x", don't
       fetch a new one if it was published in the last 2 hours.
-      - How does this interact with the 'recognized hash' rule?
-    - Do not ask for any routers until we have 2 networkstatuses.
-    - Client side:
-      - Keep a record of which hash is most desirable for each router inside
+      X Don't, actually. This is the authorities' job to straighten out.
+    o Do not ask for any routers until we have 2 networkstatuses.
+    . Client side:
+      o Keep a record of which hash is most desirable for each router inside
         local_routerstatus_t.
-        - If any hash is listed by two or more networkstatuses, the most
+        o If any hash is listed by two or more networkstatuses, the most
           recent such hash is most desirable.
-        - Otherwise, the most recent is desirable.
-      - Once we've accepted a router, it's okay.
-      - Do not accept a router that no networkstatus lists. (This should maybe
+        o Otherwise, the most recent is desirable.
+      o Once we've accepted a router, it's okay.
+      o Do not accept a router that no networkstatus lists. (This should maybe
         get stricter.)
-      - Download by fingerprint.
-      - Reset failure count to zero when hash changes.
-    - Mirrors and authorities:
-      - Every time we hear a new networkstatus, we want every hash it lists.
-      - Make sure that we are always willing to keep at least N routerinfos
+      o Download by descriptor digest.
+      o Reset failure count to zero when hash changes.
+      . Test
+      - Do we want to rate-limit downloads of each identity?
+    . Mirrors and authorities:
+      o Every time we hear a new networkstatus, we want every hash it lists.
+      o Make sure that we are always willing to keep at least N routerinfos
         per router, where N = number of authorities.
-        - Do whatever else is needed to be sure that we don't request
+        o Do whatever else is needed to be sure that we don't request
           hashes that would be immediately discarded, or discard hashes
           that would be immediately re-requested.
-      - Only fetch routerinfo from an authority that mentions is.
-        - Only ask each authority once.
-        - Retry soon after failure.
-        - We need one bit per routerstatus for "should we download from
+      o Only fetch routerinfo from an authority that mentions is.
+        o Only ask each authority once.
+        o Retry soon after failure.
+        o We need one bit per routerstatus for "should we download from
           this guy."
       - Verify that we are actually storing retained old descriptors to our
         cache.
+      - Test.
     - Non-directories don't need to keep descriptors in memory.
 
 N - Should router info have a pointer to routerstatus?

src/or/directory.c

@@ -1034,9 +1034,9 @@ connection_dir_client_reached_eof(connection_t *conn)
     info(LD_DIR,"Received server info (size %d) from server '%s:%d'",
          (int)body_len, conn->address, conn->port);
     if (conn->requested_resource &&
-        !strcmpstart(conn->requested_resource,"fp/")) {
+        !strcmpstart(conn->requested_resource,"d/")) {
       which = smartlist_create();
-      dir_split_resource_into_fingerprints(conn->requested_resource+3,
+      dir_split_resource_into_fingerprints(conn->requested_resource+2,
                                            which, NULL, 0);
       n_asked_for = smartlist_len(which);
     }

src/or/or.h

@@ -759,7 +759,6 @@ typedef struct signed_descriptor_t {
 /** Information about another onion router in the network. */
 typedef struct {
   signed_descriptor_t cache_info;
-
   char *address; /**< Location of OR: either a hostname or an IP address. */
   char *nickname; /**< Human-readable OR name. */
 
@@ -797,12 +796,6 @@ typedef struct {
                             * us? */
   unsigned int is_fast:1; /** Do we think this is a fast OR? */
   unsigned int is_stable:1; /** Do we think this is a stable OR? */
-  unsigned int xx_is_recognized:1; /**< Temporary: do we think that this
-                                    * descriptor's digest is recognized?
-                                    */
-  unsigned int xx_is_extra_new:1; /**< Temporary: do we think that this
-                                   * descriptor's digest is recognized?
-                                   */
 
   /* The below items are used only by authdirservers for
    * reachability testing. */
@@ -838,15 +831,25 @@ typedef struct routerstatus_t {
                              * information with v2 of the directory
                              * protocol. (All directory caches cache v1
                              * directories.)  */
+
+  /** True if we, as a directory mirror, want to download the corresponding
+   * routerinfo from the authority who gave us this routerstatus.  (That is,
+   * if we don't have the routerinfo, and if we haven't already tried to get it
+   * from this authority.)
+   */
+  unsigned int need_to_mirror:1;
 } routerstatus_t;
 
-/** DOCDOC */
+/** Our "local" or combined view of the info from all networkstatus objects
+ * about a single router. */
 typedef struct local_routerstatus_t {
+  /** What do we believe to be the case about this router?  In this field,
+   * descriptor_digest represnets the descriptor we would most like to use for
+   * this router. */
   routerstatus_t status;
   time_t next_attempt_at; /**< When should we try this descriptor again? */
   uint8_t n_download_failures; /**< Number of failures trying to download the
                                 * most recent descriptor. */
-  unsigned int should_download:1; /**< DOCDOC */
   unsigned int name_lookup_warned:1; /**< Have we warned the user for referring
                                       * to this (unnamed) router by nickname?
                                       */
@@ -2302,8 +2305,7 @@ void update_networkstatus_downloads(time_t now);
 void update_router_descriptor_downloads(time_t now);
 void routers_update_all_from_networkstatus(void);
 void routers_update_status_from_networkstatus(smartlist_t *routers,
-                                              int reset_failures,
-                                              int assume_recognized);
+                                              int reset_failures);
 smartlist_t *router_list_superseded(void);
 int router_have_minimum_dir_info(void);
 void networkstatus_list_update_recent(time_t now);