Refactor code that matches up routers with the same identity in votes

This makes 'routerstatus collation' into a first-class concept, so
we can change how that works for prop220.

1 files changed, 122 insertions, 0 deletions

diff --git a/src/or/dircollate.c b/src/or/dircollate.c
new file mode 100644
index 0000000000..92f3dcc2e5
--- /dev/null
+++ b/src/or/dircollate.c
@@ -0,0 +1,122 @@
+/* Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2014, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file dircollate.c
+ *
+ * \brief Collation code for figuring out which identities to vote for in
+ *   the directory voting process.
+ */
+
+#define DIRCOLLATE_PRIVATE
+#include "dircollate.h"
+
+static void dircollator_collate_by_rsa(dircollator_t *dc);
+
+static void
+dircollator_add_routerstatus(dircollator_t *dc,
+                             int vote_num,
+                             networkstatus_t *vote,
+                             vote_routerstatus_t *vrs)
+{
+  const char *id = vrs->status.identity_digest;
+
+  (void) vote;
+  vote_routerstatus_t **vrs_lst = digestmap_get(dc->by_rsa_sha1, id);
+  if (NULL == vrs_lst) {
+    vrs_lst = tor_calloc(sizeof(vote_routerstatus_t *), dc->n_votes);
+    digestmap_set(dc->by_rsa_sha1, id, vrs_lst);
+  }
+
+  tor_assert(vrs_lst[vote_num] == NULL);
+  vrs_lst[vote_num] = vrs;
+}
+
+dircollator_t *
+dircollator_new(int n_votes, int n_authorities)
+{
+  dircollator_t *dc = tor_malloc_zero(sizeof(dircollator_t));
+
+  tor_assert(n_votes <= n_authorities);
+
+  dc->n_votes = n_votes;
+  dc->n_authorities = n_authorities;
+
+  dc->by_rsa_sha1 = digestmap_new();
+
+  return dc;
+}
+
+void
+dircollator_free(dircollator_t *dc)
+{
+  if (!dc)
+    return;
+
+  digestmap_free(dc->by_rsa_sha1, tor_free_);
+
+  tor_free(dc);
+}
+
+void
+dircollator_add_vote(dircollator_t *dc, networkstatus_t *v)
+{
+  tor_assert(v->type == NS_TYPE_VOTE);
+  tor_assert(dc->next_vote_num < dc->n_votes);
+  tor_assert(!dc->is_collated);
+
+  const int votenum = dc->next_vote_num++;
+
+  SMARTLIST_FOREACH_BEGIN(v->routerstatus_list, vote_routerstatus_t *, vrs) {
+    dircollator_add_routerstatus(dc, votenum, v, vrs);
+  } SMARTLIST_FOREACH_END(vrs);
+}
+
+void
+dircollator_collate(dircollator_t *dc)
+{
+  dircollator_collate_by_rsa(dc);
+}
+
+static void
+dircollator_collate_by_rsa(dircollator_t *dc)
+{
+  tor_assert(!dc->is_collated);
+
+  dc->all_rsa_sha1_lst = smartlist_new();
+
+  const int total_authorities = dc->n_authorities;
+
+  DIGESTMAP_FOREACH(dc->by_rsa_sha1, k, vote_routerstatus_t **, vrs_lst) {
+    int n = 0, i;
+    for (i = 0; i < dc->n_votes; ++i) {
+      if (vrs_lst[i] != NULL)
+        ++n;
+    }
+
+    if (n <= total_authorities / 2)
+      continue;
+
+    smartlist_add(dc->all_rsa_sha1_lst, (char *)k);
+  } DIGESTMAP_FOREACH_END;
+
+  smartlist_sort_digests(dc->all_rsa_sha1_lst);
+  dc->is_collated = 1;
+}
+
+int
+dircollator_n_routers(dircollator_t *dc)
+{
+  return smartlist_len(dc->all_rsa_sha1_lst);
+}
+
+vote_routerstatus_t **
+dircollator_get_votes_for_router(dircollator_t *dc, int idx)
+{
+  tor_assert(idx < smartlist_len(dc->all_rsa_sha1_lst));
+  return digestmap_get(dc->by_rsa_sha1,
+                       smartlist_get(dc->all_rsa_sha1_lst, idx));
+}
+