Make "UpdateBridgesFromAuthority" torrc option work: when bridge

users configure that and specify a bridge with an identity
fingerprint, now they will lookup the bridge descriptor at the
default bridge authority via a one-hop tunnel, but once circuits
are established they will switch to a three-hop tunnel for later
connections to the bridge authority.


svn:r11550

5 files changed, 92 insertions, 53 deletions

diff --git a/ChangeLog b/ChangeLog
index 05e653dca0..39970eea52 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,14 @@ Changes in version 0.2.0.7-alpha - 2007-09-21
     - Set up moria1 and tor26 as the first v3 directory authorities. See
       doc/spec/dir-spec.txt for details on the new directory design.
 
+  o Major features (bridges):
+    - Make "UpdateBridgesFromAuthority" torrc option work: when bridge
+      users configure that and specify a bridge with an identity
+      fingerprint, now they will lookup the bridge descriptor at the
+      default bridge authority via a one-hop tunnel, but once circuits
+      are established they will switch to a three-hop tunnel for later
+      connections to the bridge authority.
+
   o Minor features (security):
     - As a client, do not believe any server that tells us that any address
       maps to an internal address space.
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 2f88c85e88..32077a4525 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -2927,6 +2927,9 @@ fetch_bridge_descriptors(time_t now)
       ask_bridge_directly = tor_digest_is_zero(bridge->identity) ||
                             !options->UpdateBridgesFromAuthority ||
                             !num_bridge_auths;
+      log_debug(LD_DIR, "ask_bridge_directly=%d (%d, %d, %d)",
+                ask_bridge_directly, tor_digest_is_zero(bridge->identity),
+                !options->UpdateBridgesFromAuthority, !num_bridge_auths);
 
       if (ask_bridge_directly &&
           !fascist_firewall_allows_address_or(bridge->addr, bridge->port)) {
@@ -2961,7 +2964,7 @@ fetch_bridge_descriptors(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, 1);
+                ROUTER_PURPOSE_BRIDGE, resource, 0);
       }
     });
 }
diff --git a/src/or/directory.c b/src/or/directory.c
index 05b68b6777..28612a9415 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -49,7 +49,8 @@ static void dir_networkstatus_download_failed(smartlist_t *failed,
                                               int status_code);
 static void dir_routerdesc_download_failed(smartlist_t *failed,
                                            int status_code,
-                                           int was_extrainfo);
+                                           int was_extrainfo,
+                                           int was_descriptor_digests);
 static void note_request(const char *key, size_t bytes);
 
 /********* START VARIABLES **********/
@@ -78,8 +79,8 @@ purpose_needs_anonymity(uint8_t dir_purpose, uint8_t router_purpose)
 {
   if (get_options()->AllDirActionsPrivate)
     return 1;
-  if (router_purpose == ROUTER_PURPOSE_BRIDGE)
-    return 1; /* if we have to ask, better make it anonymous */
+  if (router_purpose == ROUTER_PURPOSE_BRIDGE && has_completed_circuit)
+    return 1; /* if no circuits yet, we may need this info to bootstrap. */
   if (dir_purpose == DIR_PURPOSE_FETCH_DIR ||
       dir_purpose == DIR_PURPOSE_UPLOAD_DIR ||
       dir_purpose == DIR_PURPOSE_UPLOAD_VOTE ||
@@ -307,37 +308,39 @@ directory_get_from_dirserver(uint8_t dir_purpose, uint8_t router_purpose,
   if (!options->FetchServerDescriptors && type != HIDSERV_AUTHORITY)
     return;
 
-  if (!get_via_tor && options->UseBridges) {
-    /* want to ask a running bridge for which we have a descriptor. */
-    routerinfo_t *ri = choose_random_entry(NULL);
-    if (ri) {
-      directory_initiate_command(ri->address, ri->addr,
-                                 ri->or_port, 0,
-                                 1, ri->cache_info.identity_digest,
-                                 dir_purpose,
-                                 router_purpose,
-                                 0, resource, NULL, 0);
-    } else
-      log_notice(LD_DIR, "Ignoring directory request, since no bridge "
-                         "nodes are available yet.");
-    return;
-  } else if (!get_via_tor) {
-    if (prefer_authority) {
-      /* only ask authdirservers, and don't ask myself */
-      rs = router_pick_trusteddirserver(type, 1, 1,
-                                        retry_if_no_servers);
-    }
-    if (!rs) {
-      /* anybody with a non-zero dirport will do */
-      rs = router_pick_directory_server(1, 1, type,
-                                        retry_if_no_servers);
-      if (!rs) {
-        log_info(LD_DIR, "No router found for %s; falling back to "
-                 "dirserver list.", dir_conn_purpose_to_string(dir_purpose));
+  if (!get_via_tor) {
+    if (options->UseBridges && type != BRIDGE_AUTHORITY) {
+      /* want to ask a running bridge for which we have a descriptor. */
+      routerinfo_t *ri = choose_random_entry(NULL);
+      if (ri) {
+        directory_initiate_command(ri->address, ri->addr,
+                                   ri->or_port, 0,
+                                   1, ri->cache_info.identity_digest,
+                                   dir_purpose,
+                                   router_purpose,
+                                   0, resource, NULL, 0);
+      } else
+        log_notice(LD_DIR, "Ignoring directory request, since no bridge "
+                           "nodes are available yet.");
+      return;
+    } else {
+      if (prefer_authority || type == BRIDGE_AUTHORITY) {
+        /* only ask authdirservers, and don't ask myself */
         rs = router_pick_trusteddirserver(type, 1, 1,
                                           retry_if_no_servers);
-        if (!rs)
-          get_via_tor = 1; /* last resort: try routing it via Tor */
+      }
+      if (!rs && type != BRIDGE_AUTHORITY) {
+        /* anybody with a non-zero dirport will do */
+        rs = router_pick_directory_server(1, 1, type,
+                                          retry_if_no_servers);
+        if (!rs) {
+          log_info(LD_DIR, "No router found for %s; falling back to "
+                   "dirserver list.", dir_conn_purpose_to_string(dir_purpose));
+          rs = router_pick_trusteddirserver(type, 1, 1,
+                                            retry_if_no_servers);
+          if (!rs)
+            get_via_tor = 1; /* last resort: try routing it via Tor */
+        }
       }
     }
   } else { /* get_via_tor */
@@ -1342,6 +1345,8 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
     int was_ei = conn->_base.purpose == DIR_PURPOSE_FETCH_EXTRAINFO;
     smartlist_t *which = NULL;
     int n_asked_for = 0;
+    int descriptor_digests = conn->requested_resource &&
+                             !strcmpstart(conn->requested_resource,"d/");
     log_info(LD_DIR,"Received %s (size %d) from server '%s:%d'",
              was_ei ? "extra server info" : "server info",
              (int)body_len, conn->_base.address, conn->_base.port);
@@ -1350,9 +1355,11 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
     else
       note_request(was_compressed?"dl/server.z":"dl/server", orig_len);
     if (conn->requested_resource &&
-        !strcmpstart(conn->requested_resource,"d/")) {
+        (!strcmpstart(conn->requested_resource,"d/") ||
+         !strcmpstart(conn->requested_resource,"fp/"))) {
       which = smartlist_create();
-      dir_split_resource_into_fingerprints(conn->requested_resource+2,
+      dir_split_resource_into_fingerprints(conn->requested_resource +
+                                             (descriptor_digests ? 2 : 3),
                                            which, NULL, 0, 0);
       n_asked_for = smartlist_len(which);
     }
@@ -1370,7 +1377,8 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
       if (!which) {
         connection_dir_download_routerdesc_failed(conn);
       } else {
-        dir_routerdesc_download_failed(which, status_code, was_ei);
+        dir_routerdesc_download_failed(which, status_code,
+                                       was_ei, descriptor_digests);
         SMARTLIST_FOREACH(which, char *, cp, tor_free(cp));
         smartlist_free(which);
       }
@@ -1391,10 +1399,11 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
                     get_options()->UseBridges)))) {
       /* as we learn from them, we remove them from 'which' */
       if (was_ei) {
-        router_load_extrainfo_from_string(body, NULL, SAVED_NOWHERE, which);
+        router_load_extrainfo_from_string(body, NULL, SAVED_NOWHERE, which,
+                                          descriptor_digests);
       } else {
         router_load_routers_from_string(body, NULL, SAVED_NOWHERE, which,
-                                        conn->router_purpose);
+                               descriptor_digests, conn->router_purpose);
         directory_info_has_arrived(now, 0);
       }
     }
@@ -1403,7 +1412,8 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
                n_asked_for-smartlist_len(which), n_asked_for,
                conn->_base.address, (int)conn->_base.port);
       if (smartlist_len(which)) {
-        dir_routerdesc_download_failed(which, status_code, was_ei);
+        dir_routerdesc_download_failed(which, status_code,
+                                       was_ei, descriptor_digests);
       }
       SMARTLIST_FOREACH(which, char *, cp, tor_free(cp));
       smartlist_free(which);
@@ -2527,15 +2537,19 @@ dir_networkstatus_download_failed(smartlist_t *failed, int status_code)
 }
 
 /** Called when one or more routerdesc (or extrainfo, if <b>was_extrainfo</b>)
- * fetches have failed (with uppercase fingerprints listed in
- * <b>failed</b>). */
+ * fetches have failed (with uppercase fingerprints listed in <b>failed</b>,
+ * either as descriptor digests or as identity digests based on
+ * <b>was_descriptor_digests</b>).
+ */
 static void
 dir_routerdesc_download_failed(smartlist_t *failed, int status_code,
-                               int was_extrainfo)
+                               int was_extrainfo, int was_descriptor_digests)
 {
   char digest[DIGEST_LEN];
   time_t now = time(NULL);
   int server = server_mode(get_options()) && get_options()->DirPort;
+  if (!was_descriptor_digests)
+    return; /* FFFF should implement this someday */
   SMARTLIST_FOREACH(failed, const char *, cp,
   {
     download_status_t *dls = NULL;
diff --git a/src/or/or.h b/src/or/or.h
index df2b716ae3..317439dfff 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -3514,10 +3514,12 @@ int router_load_single_router(const char *s, uint8_t purpose,
 void router_load_routers_from_string(const char *s, const char *eos,
                                      saved_location_t saved_location,
                                      smartlist_t *requested_fingerprints,
+                                     int descriptor_digests,
                                      uint8_t purpose);
 void router_load_extrainfo_from_string(const char *s, const char *eos,
                                        saved_location_t saved_location,
-                                       smartlist_t *requested_fps);
+                                       smartlist_t *requested_fps,
+                                       int descriptor_digests);
 
 typedef enum {
   NS_FROM_CACHE, NS_FROM_DIR_BY_FP, NS_FROM_DIR_ALL, NS_GENERATED
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index 33ce081173..fbb99834e8 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -724,11 +724,11 @@ router_reload_router_list_impl(desc_store_t *store)
     if (extrainfo)
       router_load_extrainfo_from_string(store->mmap->data,
                                         store->mmap->data+store->mmap->size,
-                                        SAVED_IN_CACHE, NULL);
+                                        SAVED_IN_CACHE, NULL, 0);
     else
       router_load_routers_from_string(store->mmap->data,
                                       store->mmap->data+store->mmap->size,
-                                      SAVED_IN_CACHE, NULL,
+                                      SAVED_IN_CACHE, NULL, 0,
                                       ROUTER_PURPOSE_GENERAL);
   }
 
@@ -738,10 +738,11 @@ router_reload_router_list_impl(desc_store_t *store)
     contents = read_file_to_str(fname, RFTS_BIN|RFTS_IGNORE_MISSING, &st);
   if (contents) {
     if (extrainfo)
-      router_load_extrainfo_from_string(contents, NULL,SAVED_IN_JOURNAL, NULL);
+      router_load_extrainfo_from_string(contents, NULL,SAVED_IN_JOURNAL,
+                                        NULL, 0);
     else
-      router_load_routers_from_string(contents, NULL, SAVED_IN_JOURNAL, NULL,
-                                      ROUTER_PURPOSE_GENERAL);
+      router_load_routers_from_string(contents, NULL, SAVED_IN_JOURNAL,
+                                      NULL, 0, ROUTER_PURPOSE_GENERAL);
     store->journal_len = (size_t) st.st_size;
     tor_free(contents);
   }
@@ -3128,14 +3129,18 @@ router_load_single_router(const char *s, uint8_t purpose, const char **msg)
  * the journal.
  *
  * If <b>requested_fingerprints</b> is provided, it must contain a list of
- * uppercased identity fingerprints.  Do not update any router whose
+ * uppercased fingerprints.  Do not update any router whose
  * fingerprint is not on the list; after updating a router, remove its
  * fingerprint from the list.
+ *
+ * If <b>descriptor_digests</b> is non-zero, then the requested_fingerprints
+ * are descriptor digests. Otherwise they are identity digests.
  */
 void
 router_load_routers_from_string(const char *s, const char *eos,
                                 saved_location_t saved_location,
                                 smartlist_t *requested_fingerprints,
+                                int descriptor_digests,
                                 uint8_t purpose)
 {
   smartlist_t *routers = smartlist_create(), *changed = smartlist_create();
@@ -3151,9 +3156,11 @@ router_load_routers_from_string(const char *s, const char *eos,
 
   SMARTLIST_FOREACH(routers, routerinfo_t *, ri,
   {
-    base16_encode(fp, sizeof(fp), ri->cache_info.signed_descriptor_digest,
-                  DIGEST_LEN);
     if (requested_fingerprints) {
+      base16_encode(fp, sizeof(fp), descriptor_digests ?
+                      ri->cache_info.signed_descriptor_digest :
+                      ri->cache_info.identity_digest,
+                    DIGEST_LEN);
       if (smartlist_string_isin(requested_fingerprints, fp)) {
         smartlist_string_remove(requested_fingerprints, fp);
       } else {
@@ -3195,7 +3202,8 @@ router_load_routers_from_string(const char *s, const char *eos,
 void
 router_load_extrainfo_from_string(const char *s, const char *eos,
                                   saved_location_t saved_location,
-                                  smartlist_t *requested_fingerprints)
+                                  smartlist_t *requested_fingerprints,
+                                  int descriptor_digests)
 {
   smartlist_t *extrainfo_list = smartlist_create();
   const char *msg;
@@ -3208,9 +3216,13 @@ router_load_extrainfo_from_string(const char *s, const char *eos,
   SMARTLIST_FOREACH(extrainfo_list, extrainfo_t *, ei, {
       if (requested_fingerprints) {
         char fp[HEX_DIGEST_LEN+1];
-        base16_encode(fp, sizeof(fp), ei->cache_info.signed_descriptor_digest,
+        base16_encode(fp, sizeof(fp), descriptor_digests ?
+                        ei->cache_info.signed_descriptor_digest :
+                        ei->cache_info.identity_digest,
                       DIGEST_LEN);
         smartlist_string_remove(requested_fingerprints, fp);
+        /* XXX020 We silently let people stuff us with extrainfos we
+         * didn't ask for. Is this a problem? -RD */
       }
       router_add_extrainfo_to_routerlist(ei, &msg, from_cache, !from_cache);
     });