1 files changed, 70 insertions, 12 deletions

diff --git a/src/or/microdesc.c b/src/or/microdesc.c
index 11249910ca..ec85de0d6b 100644
--- a/src/or/microdesc.c
+++ b/src/or/microdesc.c
@@ -45,12 +45,7 @@ struct microdesc_cache_t {
 static INLINE unsigned int
 microdesc_hash_(microdesc_t *md)
 {
-  unsigned *d = (unsigned*)md->digest;
-#if SIZEOF_INT == 4
-  return d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[6] ^ d[7];
-#else
-  return d[0] ^ d[1] ^ d[2] ^ d[3];
-#endif
+  return (unsigned) siphash24g(md->digest, sizeof(md->digest));
 }
 
 /** Helper: compares <b>a</b> and </b> for equality for hash-table purposes. */
@@ -280,6 +275,7 @@ void
 microdesc_cache_clear(microdesc_cache_t *cache)
 {
   microdesc_t **entry, **next;
+
   for (entry = HT_START(microdesc_map, &cache->map); entry; entry = next) {
     microdesc_t *md = *entry;
     next = HT_NEXT_RMV(microdesc_map, &cache->map, entry);
@@ -288,7 +284,13 @@ microdesc_cache_clear(microdesc_cache_t *cache)
   }
   HT_CLEAR(microdesc_map, &cache->map);
   if (cache->cache_content) {
-    tor_munmap_file(cache->cache_content);
+    int res = tor_munmap_file(cache->cache_content);
+    if (res != 0) {
+      log_warn(LD_FS,
+               "tor_munmap_file() failed clearing microdesc cache; "
+               "we are probably about to leak memory.");
+      /* TODO something smarter? */
+    }
     cache->cache_content = NULL;
   }
   cache->total_len_seen = 0;
@@ -368,7 +370,9 @@ microdesc_cache_clean(microdesc_cache_t *cache, time_t cutoff, int force)
     cutoff = now - TOLERATE_MICRODESC_AGE;
 
   for (mdp = HT_START(microdesc_map, &cache->map); mdp != NULL; ) {
-    if ((*mdp)->last_listed < cutoff) {
+    const int is_old = (*mdp)->last_listed < cutoff;
+    const unsigned held_by_nodes = (*mdp)->held_by_nodes;
+    if (is_old && !held_by_nodes) {
       ++dropped;
       victim = *mdp;
       mdp = HT_NEXT_RMV(microdesc_map, &cache->map, mdp);
@@ -376,6 +380,54 @@ microdesc_cache_clean(microdesc_cache_t *cache, time_t cutoff, int force)
       bytes_dropped += victim->bodylen;
       microdesc_free(victim);
     } else {
+      if (is_old) {
+        /* It's old, but it has held_by_nodes set.  That's not okay. */
+        /* Let's try to diagnose and fix #7164 . */
+        smartlist_t *nodes = nodelist_find_nodes_with_microdesc(*mdp);
+        const networkstatus_t *ns = networkstatus_get_latest_consensus();
+        long networkstatus_age = -1;
+        if (ns) {
+          networkstatus_age = now - ns->valid_after;
+        }
+        log_warn(LD_BUG, "Microdescriptor seemed very old "
+                 "(last listed %d hours ago vs %d hour cutoff), but is still "
+                 "marked as being held by %d node(s). I found %d node(s) "
+                 "holding it. Current networkstatus is %ld hours old.",
+                 (int)((now - (*mdp)->last_listed) / 3600),
+                 (int)((now - cutoff) / 3600),
+                 held_by_nodes,
+                 smartlist_len(nodes),
+                 networkstatus_age / 3600);
+
+        SMARTLIST_FOREACH_BEGIN(nodes, const node_t *, node) {
+          const char *rs_match = "No RS";
+          const char *rs_present = "";
+          if (node->rs) {
+            if (tor_memeq(node->rs->descriptor_digest,
+                          (*mdp)->digest, DIGEST256_LEN)) {
+              rs_match = "Microdesc digest in RS matches";
+            } else {
+              rs_match = "Microdesc digest in RS does match";
+            }
+            if (ns) {
+              /* This should be impossible, but let's see! */
+              rs_present = " RS not present in networkstatus.";
+              SMARTLIST_FOREACH(ns->routerstatus_list, routerstatus_t *,rs, {
+                if (rs == node->rs) {
+                  rs_present = " RS okay in networkstatus.";
+                }
+              });
+            }
+          }
+          log_warn(LD_BUG, "  [%d]: ID=%s. md=%p, rs=%p, ri=%p. %s.%s",
+                   node_sl_idx,
+                   hex_str(node->identity, DIGEST_LEN),
+                   node->md, node->rs, node->ri, rs_match, rs_present);
+        } SMARTLIST_FOREACH_END(node);
+        smartlist_free(nodes);
+        (*mdp)->last_listed = now;
+      }
+
       ++kept;
       mdp = HT_NEXT(microdesc_map, &cache->map, mdp);
     }
@@ -434,7 +486,7 @@ int
 microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
 {
   open_file_t *open_file;
-  int fd = -1;
+  int fd = -1, res;
   microdesc_t **mdp;
   smartlist_t *wrote;
   ssize_t size;
@@ -501,8 +553,14 @@ microdesc_cache_rebuild(microdesc_cache_t *cache, int force)
 
   /* We must do this unmap _before_ we call finish_writing_to_file(), or
    * windows will not actually replace the file. */
-  if (cache->cache_content)
-    tor_munmap_file(cache->cache_content);
+  if (cache->cache_content) {
+    res = tor_munmap_file(cache->cache_content);
+    if (res != 0) {
+      log_warn(LD_FS,
+               "Failed to unmap old microdescriptor cache while rebuilding");
+    }
+    cache->cache_content = NULL;
+  }
 
   if (finish_writing_to_file(open_file) < 0) {
     log_warn(LD_DIR, "Error rebuilding microdescriptor cache: %s",
@@ -726,7 +784,7 @@ update_microdesc_downloads(time_t now)
   smartlist_t *missing;
   digestmap_t *pending;
 
-  if (should_delay_dir_fetches(options))
+  if (should_delay_dir_fetches(options, NULL))
     return;
   if (directory_too_idle_to_fetch_descriptors(options, now))
     return;