[tor-commits] [tor/maint-0.2.4] Be more robust when excluding existing nodes as new dirguards

nickm at torproject.org nickm at torproject.org
Mon Mar 18 18:50:25 UTC 2013


commit 1070a720ad7f45fa82b77be0512056a06e535b72
Author: Nick Mathewson <nickm at torproject.org>
Date:   Thu Feb 14 12:06:59 2013 -0500

    Be more robust when excluding existing nodes as new dirguards
    
    In addition to rejecting them post-hoc, avoid picking them in the
    first place.  This makes us less likely to decide that we can't add
    guards at all.
---
 src/or/circuitbuild.c |    1 +
 src/or/entrynodes.c   |    2 +-
 src/or/or.h           |    4 ++++
 src/or/routerlist.c   |    3 +++
 4 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 163afd3..c2f3953 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -3397,6 +3397,7 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state)
     });
   }
   /* and exclude current entry guards and their families, if applicable */
+  /*XXXX025 use the using_as_guard flag to accomplish this.*/
   if (options->UseEntryGuards) {
     SMARTLIST_FOREACH(get_entry_guards(), const entry_guard_t *, entry,
       {
diff --git a/src/or/entrynodes.c b/src/or/entrynodes.c
index 3e471ed..5dd2790 100644
--- a/src/or/entrynodes.c
+++ b/src/or/entrynodes.c
@@ -362,7 +362,7 @@ add_an_entry_guard(const node_t *chosen, int reset_status, int prepend,
   } else {
     const routerstatus_t *rs;
     rs = router_pick_directory_server(MICRODESC_DIRINFO|V3_DIRINFO,
-                                      PDS_PREFER_TUNNELED_DIR_CONNS_);
+                                      PDS_PREFER_TUNNELED_DIR_CONNS_|PDS_FOR_GUARD);
     if (!rs)
       return NULL;
     node = node_get_by_id(rs->identity_digest);
diff --git a/src/or/or.h b/src/or/or.h
index df69674..1cb9ef2 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -4760,6 +4760,10 @@ typedef struct dir_server_t {
 #define PDS_NO_EXISTING_SERVERDESC_FETCH (1<<3)
 #define PDS_NO_EXISTING_MICRODESC_FETCH (1<<4)
 
+/** This node is to be chosen as a directory guard, so don't choose any
+ * node that's currently a guard. */
+#define PDS_FOR_GUARD (1<<5)
+
 #define PDS_PREFER_TUNNELED_DIR_CONNS_ (1<<16)
 
 /** Possible ways to weight routers when choosing one randomly.  See
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index 90b707b..837245d 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -1153,6 +1153,7 @@ router_pick_directory_server_impl(dirinfo_type_t type, int flags)
   int requireother = ! (flags & PDS_ALLOW_SELF);
   int fascistfirewall = ! (flags & PDS_IGNORE_FASCISTFIREWALL);
   int prefer_tunnel = (flags & PDS_PREFER_TUNNELED_DIR_CONNS_);
+  int for_guard = (flags & PDS_FOR_GUARD);
   int try_excluding = 1, n_excluded = 0;
 
   if (!consensus)
@@ -1192,6 +1193,8 @@ router_pick_directory_server_impl(dirinfo_type_t type, int flags)
     if ((type & MICRODESC_DIRINFO) && !is_trusted &&
         !node->rs->version_supports_microdesc_cache)
       continue;
+    if (for_guard && node->using_as_guard)
+      continue; /* Don't make the same node a guard twice. */
     if (try_excluding &&
         routerset_contains_routerstatus(options->ExcludeNodes, status,
                                         country)) {





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