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.

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));
+}
+

src/or/dircollate.h

@@ -0,0 +1,44 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * 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 dirvote.h
+ * \brief Header file for dirvote.c.
+ **/
+
+#ifndef TOR_DIRCOLLATE_H
+#define TOR_DIRCOLLATE_H
+
+#include "testsupport.h"
+#include "or.h"
+
+typedef struct dircollator_s dircollator_t;
+
+dircollator_t *dircollator_new(int n_votes, int n_authorities);
+void dircollator_free(dircollator_t *obj);
+void dircollator_add_vote(dircollator_t *dc, networkstatus_t *v);
+
+void dircollator_collate(dircollator_t *dc);
+
+int dircollator_n_routers(dircollator_t *dc);
+vote_routerstatus_t **dircollator_get_votes_for_router(dircollator_t *dc,
+                                                       int idx);
+
+#ifdef DIRCOLLATE_PRIVATE
+struct dircollator_s {
+  /**DOCDOC */
+  int is_collated;
+  int n_votes;
+  int n_authorities;
+
+  int next_vote_num;
+  digestmap_t *by_rsa_sha1;
+
+  smartlist_t *all_rsa_sha1_lst;
+};
+#endif
+
+#endif

src/or/dirvote.c

@@ -6,6 +6,7 @@
 #define DIRVOTE_PRIVATE
 #include "or.h"
 #include "config.h"
+#include "dircollate.h"
 #include "directory.h"
 #include "dirserv.h"
 #include "dirvote.h"
@@ -782,28 +783,6 @@ networkstatus_check_weights(int64_t Wgg, int64_t Wgd, int64_t Wmg,
   return berr;
 }
 
-#if 0
-/** DOCDOC */
-static vote_identity_map_t *
-networkstatus_compute_identity_mapping(const smartlist_t *votes)
-{
-  vote_identity_map_t *map = vote_identity_map_new();
-
-  SMARTLIST_FOREACH_BEGIN(votes, networkstatus_t *, vote) {
-    SMARTLIST_FOREACH_BEGIN(vote->routerstatus_list,
-                            vote_routerstatus_t *, vrs) {
-      vote_identity_map_add(map, vrs->status.identity_digest,
-                            vrs->has_ed25519_listing ? vrs->ed25519_id : NULL,
-                            vote_sl_idx);
-    } SMARTLIST_FOREACH_END(vrs);
-  } SMARTLIST_FOREACH_END(vote);
-
-  vote_identity_map_resolve(map);
-
-  return map;
-}
-#endif
-
 /**
  * This function computes the bandwidth weights for consensus method 10.
  *
@@ -1161,9 +1140,7 @@ networkstatus_compute_consensus(smartlist_t *votes,
   char *params = NULL;
   char *packages = NULL;
   int added_weights = 0;
-#if 0
-  vote_identity_map_t *id_map = NULL;
-#endif
+  dircollator_t *collator = NULL;
   tor_assert(flavor == FLAV_NS || flavor == FLAV_MICRODESC);
   tor_assert(total_authorities >= smartlist_len(votes));
 
@@ -1519,16 +1496,24 @@ networkstatus_compute_consensus(smartlist_t *votes,
        }
     );
 
-#if 0
-    id_map = networkstatus_compute_identity_mapping(votes);
-#endif
+    /* Populate the collator */
+    collator = dircollator_new(smartlist_len(votes), total_authorities);
+    SMARTLIST_FOREACH_BEGIN(votes, networkstatus_t *, v) {
+      dircollator_add_vote(collator, v);
+    } SMARTLIST_FOREACH_END(v);
+
+    dircollator_collate(collator);
 
     /* Now go through all the votes */
     flag_counts = tor_calloc(smartlist_len(flags), sizeof(int));
-    while (1) {
+    const int num_routers = dircollator_n_routers(collator);
+    for (i = 0; i < num_routers; ++i) {
+      vote_routerstatus_t **vrs_lst =
+        dircollator_get_votes_for_router(collator, i);
+
       vote_routerstatus_t *rs;
       routerstatus_t rs_out;
-      const char *lowest_id = NULL;
+      const char *current_rsa_id = NULL;
       const char *chosen_version;
       const char *chosen_name = NULL;
       int exitsummary_disagreement = 0;
@@ -1536,23 +1521,9 @@ networkstatus_compute_consensus(smartlist_t *votes,
       int is_guard = 0, is_exit = 0, is_bad_exit = 0;
       int naming_conflict = 0;
       int n_listing = 0;
-      int i;
       char microdesc_digest[DIGEST256_LEN];
       tor_addr_port_t alt_orport = {TOR_ADDR_NULL, 0};
 
-      /* Of the next-to-be-considered digest in each voter, which is first? */
-      SMARTLIST_FOREACH(votes, networkstatus_t *, v, {
-        if (index[v_sl_idx] < size[v_sl_idx]) {
-          rs = smartlist_get(v->routerstatus_list, index[v_sl_idx]);
-          if (!lowest_id ||
-              fast_memcmp(rs->status.identity_digest,
-                          lowest_id, DIGEST_LEN) < 0)
-            lowest_id = rs->status.identity_digest;
-        }
-      });
-      if (!lowest_id) /* we're out of routers. */
-        break;
-
       memset(flag_counts, 0, sizeof(int)*smartlist_len(flags));
       smartlist_clear(matching_descs);
       smartlist_clear(chosen_flags);
@@ -1562,29 +1533,25 @@ networkstatus_compute_consensus(smartlist_t *votes,
       num_guardfraction_inputs = 0;
 
       /* Okay, go through all the entries for this digest. */
-      SMARTLIST_FOREACH_BEGIN(votes, networkstatus_t *, v) {
-        if (index[v_sl_idx] >= size[v_sl_idx])
-          continue; /* out of entries. */
-        rs = smartlist_get(v->routerstatus_list, index[v_sl_idx]);
-        if (fast_memcmp(rs->status.identity_digest, lowest_id, DIGEST_LEN))
-          continue; /* doesn't include this router. */
-        /* At this point, we know that we're looking at a routerstatus with
-         * identity "lowest".
-         */
-        ++index[v_sl_idx];
+      for (int voter_idx = 0; voter_idx < smartlist_len(votes); ++voter_idx) {
+        if (vrs_lst[voter_idx] == NULL)
+          continue; /* This voter had nothig to say about this entry. */
+        rs = vrs_lst[voter_idx];
         ++n_listing;
 
+        current_rsa_id = rs->status.identity_digest;
+
         smartlist_add(matching_descs, rs);
         if (rs->version && rs->version[0])
           smartlist_add(versions, rs->version);
 
         /* Tally up all the flags. */
-        for (i = 0; i < n_voter_flags[v_sl_idx]; ++i) {
-          if (rs->flags & (U64_LITERAL(1) << i))
-            ++flag_counts[flag_map[v_sl_idx][i]];
+        for (int flag = 0; flag < n_voter_flags[voter_idx]; ++flag) {
+          if (rs->flags & (U64_LITERAL(1) << flag))
+            ++flag_counts[flag_map[voter_idx][flag]];
         }
-        if (named_flag[v_sl_idx] >= 0 &&
-            (rs->flags & (U64_LITERAL(1) << named_flag[v_sl_idx]))) {
+        if (named_flag[voter_idx] >= 0 &&
+            (rs->flags & (U64_LITERAL(1) << named_flag[voter_idx]))) {
           if (chosen_name && strcmp(chosen_name, rs->status.nickname)) {
             log_notice(LD_DIR, "Conflict on naming for router: %s vs %s",
                        chosen_name, rs->status.nickname);
@@ -1605,7 +1572,7 @@ networkstatus_compute_consensus(smartlist_t *votes,
 
         if (rs->status.has_bandwidth)
           bandwidths_kb[num_bandwidths++] = rs->status.bandwidth_kb;
-      } SMARTLIST_FOREACH_END(v);
+      }
 
       /* We don't include this router at all unless more than half of
        * the authorities we believe in list it. */
@@ -1619,8 +1586,9 @@ networkstatus_compute_consensus(smartlist_t *votes,
                                           microdesc_digest, &alt_orport);
       /* Copy bits of that into rs_out. */
       memset(&rs_out, 0, sizeof(rs_out));
-      tor_assert(fast_memeq(lowest_id, rs->status.identity_digest,DIGEST_LEN));
-      memcpy(rs_out.identity_digest, lowest_id, DIGEST_LEN);
+      tor_assert(fast_memeq(current_rsa_id,
+                            rs->status.identity_digest,DIGEST_LEN));
+      memcpy(rs_out.identity_digest, current_rsa_id, DIGEST_LEN);
       memcpy(rs_out.descriptor_digest, rs->status.descriptor_digest,
              DIGEST_LEN);
       rs_out.addr = rs->status.addr;
@@ -1644,7 +1612,7 @@ networkstatus_compute_consensus(smartlist_t *votes,
         const char *d = strmap_get_lc(name_to_id_map, rs_out.nickname);
         if (!d) {
           is_named = is_unnamed = 0;
-        } else if (fast_memeq(d, lowest_id, DIGEST_LEN)) {
+        } else if (fast_memeq(d, current_rsa_id, DIGEST_LEN)) {
           is_named = 1; is_unnamed = 0;
         } else {
           is_named = 0; is_unnamed = 1;
@@ -2010,9 +1978,7 @@ networkstatus_compute_consensus(smartlist_t *votes,
 
  done:
 
-#if 0
-  vote_identity_map_free(id_map);
-#endif
+  dircollator_free(collator);
   tor_free(client_versions);
   tor_free(server_versions);
   tor_free(packages);

src/or/include.am

@@ -43,6 +43,7 @@ LIBTOR_A_SOURCES = \
 	src/or/connection_or.c				\
 	src/or/control.c				\
 	src/or/cpuworker.c				\
+	src/or/dircollate.c				\
 	src/or/directory.c				\
 	src/or/dirserv.c				\
 	src/or/dirvote.c				\
@@ -151,6 +152,7 @@ ORHEADERS = \
 	src/or/connection_or.h				\
 	src/or/control.h				\
 	src/or/cpuworker.h				\
+	src/or/dircollate.h				\
 	src/or/directory.h				\
 	src/or/dirserv.h				\
 	src/or/dirvote.h				\