dirvote: Move the vote creation code into dirvote.c

This code is only for dirauth so this commit moves it into the module in
dirvote.c.

No code behavior change.

Signed-off-by: David Goulet <dgoulet@torproject.org>

3 files changed, 516 insertions, 0 deletions

diff --git a/src/or/dirauth/dirvote.c b/src/or/dirauth/dirvote.c
index dd00806238..683cfdfcac 100644
--- a/src/or/dirauth/dirvote.c
+++ b/src/or/dirauth/dirvote.c
@@ -13,6 +13,7 @@
 #include "dirvote_common.h"
 #include "microdesc.h"
 #include "networkstatus.h"
+#include "nodelist.h"
 #include "parsecommon.h"
 #include "policies.h"
 #include "protover.h"
@@ -3966,3 +3967,516 @@ dirvote_dirreq_get_status_vote(const char *url, smartlist_t *items,
     smartlist_free(fps);
   }
 }
+
+/** Get the best estimate of a router's bandwidth for dirauth purposes,
+ * preferring measured to advertised values if available. */
+static uint32_t
+dirserv_get_bandwidth_for_router_kb(const routerinfo_t *ri)
+{
+  uint32_t bw_kb = 0;
+  /*
+   * Yeah, measured bandwidths in measured_bw_line_t are (implicitly
+   * signed) longs and the ones router_get_advertised_bandwidth() returns
+   * are uint32_t.
+   */
+  long mbw_kb = 0;
+
+  if (ri) {
+    /*
+     * * First try to see if we have a measured bandwidth; don't bother with
+     * as_of_out here, on the theory that a stale measured bandwidth is still
+     * better to trust than an advertised one.
+     */
+    if (dirserv_query_measured_bw_cache_kb(ri->cache_info.identity_digest,
+                                           &mbw_kb, NULL)) {
+      /* Got one! */
+      bw_kb = (uint32_t)mbw_kb;
+    } else {
+      /* If not, fall back to advertised */
+      bw_kb = router_get_advertised_bandwidth(ri) / 1000;
+    }
+  }
+
+  return bw_kb;
+}
+
+/** Helper for sorting: compares two routerinfos first by address, and then by
+ * descending order of "usefulness".  (An authority is more useful than a
+ * non-authority; a running router is more useful than a non-running router;
+ * and a router with more bandwidth is more useful than one with less.)
+ **/
+static int
+compare_routerinfo_by_ip_and_bw_(const void **a, const void **b)
+{
+  routerinfo_t *first = *(routerinfo_t **)a, *second = *(routerinfo_t **)b;
+  int first_is_auth, second_is_auth;
+  uint32_t bw_kb_first, bw_kb_second;
+  const node_t *node_first, *node_second;
+  int first_is_running, second_is_running;
+
+  /* we return -1 if first should appear before second... that is,
+   * if first is a better router. */
+  if (first->addr < second->addr)
+    return -1;
+  else if (first->addr > second->addr)
+    return 1;
+
+  /* Potentially, this next bit could cause k n lg n memeq calls.  But in
+   * reality, we will almost never get here, since addresses will usually be
+   * different. */
+
+  first_is_auth =
+    router_digest_is_trusted_dir(first->cache_info.identity_digest);
+  second_is_auth =
+    router_digest_is_trusted_dir(second->cache_info.identity_digest);
+
+  if (first_is_auth && !second_is_auth)
+    return -1;
+  else if (!first_is_auth && second_is_auth)
+    return 1;
+
+  node_first = node_get_by_id(first->cache_info.identity_digest);
+  node_second = node_get_by_id(second->cache_info.identity_digest);
+  first_is_running = node_first && node_first->is_running;
+  second_is_running = node_second && node_second->is_running;
+
+  if (first_is_running && !second_is_running)
+    return -1;
+  else if (!first_is_running && second_is_running)
+    return 1;
+
+  bw_kb_first = dirserv_get_bandwidth_for_router_kb(first);
+  bw_kb_second = dirserv_get_bandwidth_for_router_kb(second);
+
+  if (bw_kb_first > bw_kb_second)
+    return -1;
+  else if (bw_kb_first < bw_kb_second)
+    return 1;
+
+  /* They're equal! Compare by identity digest, so there's a
+   * deterministic order and we avoid flapping. */
+  return fast_memcmp(first->cache_info.identity_digest,
+                     second->cache_info.identity_digest,
+                     DIGEST_LEN);
+}
+
+/** Given a list of routerinfo_t in <b>routers</b>, return a new digestmap_t
+ * whose keys are the identity digests of those routers that we're going to
+ * exclude for Sybil-like appearance. */
+static digestmap_t *
+get_possible_sybil_list(const smartlist_t *routers)
+{
+  const or_options_t *options = get_options();
+  digestmap_t *omit_as_sybil;
+  smartlist_t *routers_by_ip = smartlist_new();
+  uint32_t last_addr;
+  int addr_count;
+  /* Allow at most this number of Tor servers on a single IP address, ... */
+  int max_with_same_addr = options->AuthDirMaxServersPerAddr;
+  if (max_with_same_addr <= 0)
+    max_with_same_addr = INT_MAX;
+
+  smartlist_add_all(routers_by_ip, routers);
+  smartlist_sort(routers_by_ip, compare_routerinfo_by_ip_and_bw_);
+  omit_as_sybil = digestmap_new();
+
+  last_addr = 0;
+  addr_count = 0;
+  SMARTLIST_FOREACH_BEGIN(routers_by_ip, routerinfo_t *, ri) {
+    if (last_addr != ri->addr) {
+      last_addr = ri->addr;
+      addr_count = 1;
+    } else if (++addr_count > max_with_same_addr) {
+      digestmap_set(omit_as_sybil, ri->cache_info.identity_digest, ri);
+    }
+  } SMARTLIST_FOREACH_END(ri);
+
+  smartlist_free(routers_by_ip);
+  return omit_as_sybil;
+}
+
+/** Given a platform string as in a routerinfo_t (possibly null), return a
+ * newly allocated version string for a networkstatus document, or NULL if the
+ * platform doesn't give a Tor version. */
+static char *
+version_from_platform(const char *platform)
+{
+  if (platform && !strcmpstart(platform, "Tor ")) {
+    const char *eos = find_whitespace(platform+4);
+    if (eos && !strcmpstart(eos, " (r")) {
+      /* XXXX Unify this logic with the other version extraction
+       * logic in routerparse.c. */
+      eos = find_whitespace(eos+1);
+    }
+    if (eos) {
+      return tor_strndup(platform, eos-platform);
+    }
+  }
+  return NULL;
+}
+
+/** Given a (possibly empty) list of config_line_t, each line of which contains
+ * a list of comma-separated version numbers surrounded by optional space,
+ * allocate and return a new string containing the version numbers, in order,
+ * separated by commas.  Used to generate Recommended(Client|Server)?Versions
+ */
+static char *
+format_versions_list(config_line_t *ln)
+{
+  smartlist_t *versions;
+  char *result;
+  versions = smartlist_new();
+  for ( ; ln; ln = ln->next) {
+    smartlist_split_string(versions, ln->value, ",",
+                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
+  }
+  sort_version_list(versions, 1);
+  result = smartlist_join_strings(versions,",",0,NULL);
+  SMARTLIST_FOREACH(versions,char *,s,tor_free(s));
+  smartlist_free(versions);
+  return result;
+}
+
+/** If there are entries in <b>routers</b> with exactly the same ed25519 keys,
+ * remove the older one.  If they are exactly the same age, remove the one
+ * with the greater descriptor digest. May alter the order of the list. */
+static void
+routers_make_ed_keys_unique(smartlist_t *routers)
+{
+  routerinfo_t *ri2;
+  digest256map_t *by_ed_key = digest256map_new();
+
+  SMARTLIST_FOREACH_BEGIN(routers, routerinfo_t *, ri) {
+    ri->omit_from_vote = 0;
+    if (ri->cache_info.signing_key_cert == NULL)
+      continue; /* No ed key */
+    const uint8_t *pk = ri->cache_info.signing_key_cert->signing_key.pubkey;
+    if ((ri2 = digest256map_get(by_ed_key, pk))) {
+      /* Duplicate; must omit one.  Set the omit_from_vote flag in whichever
+       * one has the earlier published_on. */
+      const time_t ri_pub = ri->cache_info.published_on;
+      const time_t ri2_pub = ri2->cache_info.published_on;
+      if (ri2_pub < ri_pub ||
+          (ri2_pub == ri_pub &&
+           fast_memcmp(ri->cache_info.signed_descriptor_digest,
+                       ri2->cache_info.signed_descriptor_digest,DIGEST_LEN)<0)) {
+        digest256map_set(by_ed_key, pk, ri);
+        ri2->omit_from_vote = 1;
+      } else {
+        ri->omit_from_vote = 1;
+      }
+    } else {
+      /* Add to map */
+      digest256map_set(by_ed_key, pk, ri);
+    }
+  } SMARTLIST_FOREACH_END(ri);
+
+  digest256map_free(by_ed_key, NULL);
+
+  /* Now remove every router where the omit_from_vote flag got set. */
+  SMARTLIST_FOREACH_BEGIN(routers, const routerinfo_t *, ri) {
+    if (ri->omit_from_vote) {
+      SMARTLIST_DEL_CURRENT(routers, ri);
+    }
+  } SMARTLIST_FOREACH_END(ri);
+}
+
+/** Routerstatus <b>rs</b> is part of a group of routers that are on
+ * too narrow an IP-space. Clear out its flags since we don't want it be used
+ * because of its Sybil-like appearance.
+ *
+ * Leave its BadExit flag alone though, since if we think it's a bad exit,
+ * we want to vote that way in case all the other authorities are voting
+ * Running and Exit.
+ */
+static void
+clear_status_flags_on_sybil(routerstatus_t *rs)
+{
+  rs->is_authority = rs->is_exit = rs->is_stable = rs->is_fast =
+    rs->is_flagged_running = rs->is_named = rs->is_valid =
+    rs->is_hs_dir = rs->is_v2_dir = rs->is_possible_guard = 0;
+  /* FFFF we might want some mechanism to check later on if we
+   * missed zeroing any flags: it's easy to add a new flag but
+   * forget to add it to this clause. */
+}
+
+/** Return a new networkstatus_t* containing our current opinion. (For v3
+ * authorities) */
+networkstatus_t *
+dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
+                                        authority_cert_t *cert)
+{
+  const or_options_t *options = get_options();
+  networkstatus_t *v3_out = NULL;
+  uint32_t addr;
+  char *hostname = NULL, *client_versions = NULL, *server_versions = NULL;
+  const char *contact;
+  smartlist_t *routers, *routerstatuses;
+  char identity_digest[DIGEST_LEN];
+  char signing_key_digest[DIGEST_LEN];
+  int listbadexits = options->AuthDirListBadExits;
+  routerlist_t *rl = router_get_routerlist();
+  time_t now = time(NULL);
+  time_t cutoff = now - ROUTER_MAX_AGE_TO_PUBLISH;
+  networkstatus_voter_info_t *voter = NULL;
+  vote_timing_t timing;
+  digestmap_t *omit_as_sybil = NULL;
+  const int vote_on_reachability = running_long_enough_to_decide_unreachable();
+  smartlist_t *microdescriptors = NULL;
+
+  tor_assert(private_key);
+  tor_assert(cert);
+
+  if (crypto_pk_get_digest(private_key, signing_key_digest)<0) {
+    log_err(LD_BUG, "Error computing signing key digest");
+    return NULL;
+  }
+  if (crypto_pk_get_digest(cert->identity_key, identity_digest)<0) {
+    log_err(LD_BUG, "Error computing identity key digest");
+    return NULL;
+  }
+  if (resolve_my_address(LOG_WARN, options, &addr, NULL, &hostname)<0) {
+    log_warn(LD_NET, "Couldn't resolve my hostname");
+    return NULL;
+  }
+  if (!hostname || !strchr(hostname, '.')) {
+    tor_free(hostname);
+    hostname = tor_dup_ip(addr);
+  }
+
+  if (options->VersioningAuthoritativeDir) {
+    client_versions = format_versions_list(options->RecommendedClientVersions);
+    server_versions = format_versions_list(options->RecommendedServerVersions);
+  }
+
+  contact = get_options()->ContactInfo;
+  if (!contact)
+    contact = "(none)";
+
+  /*
+   * Do this so dirserv_compute_performance_thresholds() and
+   * set_routerstatus_from_routerinfo() see up-to-date bandwidth info.
+   */
+  if (options->V3BandwidthsFile) {
+    dirserv_read_measured_bandwidths(options->V3BandwidthsFile, NULL);
+  } else {
+    /*
+     * No bandwidths file; clear the measured bandwidth cache in case we had
+     * one last time around.
+     */
+    if (dirserv_get_measured_bw_cache_size() > 0) {
+      dirserv_clear_measured_bw_cache();
+    }
+  }
+
+  /* precompute this part, since we need it to decide what "stable"
+   * means. */
+  SMARTLIST_FOREACH(rl->routers, routerinfo_t *, ri, {
+                    dirserv_set_router_is_running(ri, now);
+                    });
+
+  routers = smartlist_new();
+  smartlist_add_all(routers, rl->routers);
+  routers_make_ed_keys_unique(routers);
+  /* After this point, don't use rl->routers; use 'routers' instead. */
+  routers_sort_by_identity(routers);
+  omit_as_sybil = get_possible_sybil_list(routers);
+
+  DIGESTMAP_FOREACH(omit_as_sybil, sybil_id, void *, ignore) {
+    (void) ignore;
+    rep_hist_make_router_pessimal(sybil_id, now);
+  } DIGESTMAP_FOREACH_END;
+
+  /* Count how many have measured bandwidths so we know how to assign flags;
+   * this must come before dirserv_compute_performance_thresholds() */
+  dirserv_count_measured_bws(routers);
+
+  dirserv_compute_performance_thresholds(omit_as_sybil);
+
+  routerstatuses = smartlist_new();
+  microdescriptors = smartlist_new();
+
+  SMARTLIST_FOREACH_BEGIN(routers, routerinfo_t *, ri) {
+    if (ri->cache_info.published_on >= cutoff) {
+      routerstatus_t *rs;
+      vote_routerstatus_t *vrs;
+      node_t *node = node_get_mutable_by_id(ri->cache_info.identity_digest);
+      if (!node)
+        continue;
+
+      vrs = tor_malloc_zero(sizeof(vote_routerstatus_t));
+      rs = &vrs->status;
+      set_routerstatus_from_routerinfo(rs, node, ri, now,
+                                       listbadexits);
+
+      if (ri->cache_info.signing_key_cert) {
+        memcpy(vrs->ed25519_id,
+               ri->cache_info.signing_key_cert->signing_key.pubkey,
+               ED25519_PUBKEY_LEN);
+      }
+
+      if (digestmap_get(omit_as_sybil, ri->cache_info.identity_digest))
+        clear_status_flags_on_sybil(rs);
+
+      if (!vote_on_reachability)
+        rs->is_flagged_running = 0;
+
+      vrs->version = version_from_platform(ri->platform);
+      if (ri->protocol_list) {
+        vrs->protocols = tor_strdup(ri->protocol_list);
+      } else {
+        vrs->protocols = tor_strdup(
+                                    protover_compute_for_old_tor(vrs->version));
+      }
+      vrs->microdesc = dirvote_format_all_microdesc_vote_lines(ri, now,
+                                                               microdescriptors);
+
+      smartlist_add(routerstatuses, vrs);
+    }
+  } SMARTLIST_FOREACH_END(ri);
+
+  {
+    smartlist_t *added =
+      microdescs_add_list_to_cache(get_microdesc_cache(),
+                                   microdescriptors, SAVED_NOWHERE, 0);
+    smartlist_free(added);
+    smartlist_free(microdescriptors);
+  }
+
+  smartlist_free(routers);
+  digestmap_free(omit_as_sybil, NULL);
+
+  /* Apply guardfraction information to routerstatuses. */
+  if (options->GuardfractionFile) {
+    dirserv_read_guardfraction_file(options->GuardfractionFile,
+                                    routerstatuses);
+  }
+
+  /* This pass through applies the measured bw lines to the routerstatuses */
+  if (options->V3BandwidthsFile) {
+    dirserv_read_measured_bandwidths(options->V3BandwidthsFile,
+                                     routerstatuses);
+  } else {
+    /*
+     * No bandwidths file; clear the measured bandwidth cache in case we had
+     * one last time around.
+     */
+    if (dirserv_get_measured_bw_cache_size() > 0) {
+      dirserv_clear_measured_bw_cache();
+    }
+  }
+
+  v3_out = tor_malloc_zero(sizeof(networkstatus_t));
+
+  v3_out->type = NS_TYPE_VOTE;
+  dirvote_get_preferred_voting_intervals(&timing);
+  v3_out->published = now;
+  {
+    char tbuf[ISO_TIME_LEN+1];
+    networkstatus_t *current_consensus =
+      networkstatus_get_live_consensus(now);
+    long last_consensus_interval; /* only used to pick a valid_after */
+    if (current_consensus)
+      last_consensus_interval = current_consensus->fresh_until -
+        current_consensus->valid_after;
+    else
+      last_consensus_interval = options->TestingV3AuthInitialVotingInterval;
+    v3_out->valid_after =
+      dirvote_get_start_of_next_interval(now, (int)last_consensus_interval,
+                                         options->TestingV3AuthVotingStartOffset);
+    format_iso_time(tbuf, v3_out->valid_after);
+    log_notice(LD_DIR,"Choosing valid-after time in vote as %s: "
+               "consensus_set=%d, last_interval=%d",
+               tbuf, current_consensus?1:0, (int)last_consensus_interval);
+  }
+  v3_out->fresh_until = v3_out->valid_after + timing.vote_interval;
+  v3_out->valid_until = v3_out->valid_after +
+    (timing.vote_interval * timing.n_intervals_valid);
+  v3_out->vote_seconds = timing.vote_delay;
+  v3_out->dist_seconds = timing.dist_delay;
+  tor_assert(v3_out->vote_seconds > 0);
+  tor_assert(v3_out->dist_seconds > 0);
+  tor_assert(timing.n_intervals_valid > 0);
+
+  v3_out->client_versions = client_versions;
+  v3_out->server_versions = server_versions;
+
+  /* These are hardwired, to avoid disaster. */
+  v3_out->recommended_relay_protocols =
+    tor_strdup("Cons=1-2 Desc=1-2 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 "
+               "Link=4 LinkAuth=1 Microdesc=1-2 Relay=2");
+  v3_out->recommended_client_protocols =
+    tor_strdup("Cons=1-2 Desc=1-2 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 "
+               "Link=4 LinkAuth=1 Microdesc=1-2 Relay=2");
+  v3_out->required_client_protocols =
+    tor_strdup("Cons=1-2 Desc=1-2 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 "
+               "Link=4 LinkAuth=1 Microdesc=1-2 Relay=2");
+  v3_out->required_relay_protocols =
+    tor_strdup("Cons=1 Desc=1 DirCache=1 HSDir=1 HSIntro=3 HSRend=1 "
+               "Link=3-4 LinkAuth=1 Microdesc=1 Relay=1-2");
+
+  /* We are not allowed to vote to require anything we don't have. */
+  tor_assert(protover_all_supported(v3_out->required_relay_protocols, NULL));
+  tor_assert(protover_all_supported(v3_out->required_client_protocols, NULL));
+
+  /* We should not recommend anything we don't have. */
+  tor_assert_nonfatal(protover_all_supported(
+                                             v3_out->recommended_relay_protocols, NULL));
+  tor_assert_nonfatal(protover_all_supported(
+                                             v3_out->recommended_client_protocols, NULL));
+
+  v3_out->package_lines = smartlist_new();
+  {
+    config_line_t *cl;
+    for (cl = get_options()->RecommendedPackages; cl; cl = cl->next) {
+      if (validate_recommended_package_line(cl->value))
+        smartlist_add_strdup(v3_out->package_lines, cl->value);
+    }
+  }
+
+  v3_out->known_flags = smartlist_new();
+  smartlist_split_string(v3_out->known_flags,
+                         "Authority Exit Fast Guard Stable V2Dir Valid HSDir",
+                         0, SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
+  if (vote_on_reachability)
+    smartlist_add_strdup(v3_out->known_flags, "Running");
+  if (listbadexits)
+    smartlist_add_strdup(v3_out->known_flags, "BadExit");
+  smartlist_sort_strings(v3_out->known_flags);
+
+  if (options->ConsensusParams) {
+    v3_out->net_params = smartlist_new();
+    smartlist_split_string(v3_out->net_params,
+                           options->ConsensusParams, NULL, 0, 0);
+    smartlist_sort_strings(v3_out->net_params);
+  }
+
+  voter = tor_malloc_zero(sizeof(networkstatus_voter_info_t));
+  voter->nickname = tor_strdup(options->Nickname);
+  memcpy(voter->identity_digest, identity_digest, DIGEST_LEN);
+  voter->sigs = smartlist_new();
+  voter->address = hostname;
+  voter->addr = addr;
+  voter->dir_port = router_get_advertised_dir_port(options, 0);
+  voter->or_port = router_get_advertised_or_port(options);
+  voter->contact = tor_strdup(contact);
+  if (options->V3AuthUseLegacyKey) {
+    authority_cert_t *c = get_my_v3_legacy_cert();
+    if (c) {
+      if (crypto_pk_get_digest(c->identity_key, voter->legacy_id_digest)) {
+        log_warn(LD_BUG, "Unable to compute digest of legacy v3 identity key");
+        memset(voter->legacy_id_digest, 0, DIGEST_LEN);
+      }
+    }
+  }
+
+  v3_out->voters = smartlist_new();
+  smartlist_add(v3_out->voters, voter);
+  v3_out->cert = dirvote_authority_cert_dup(cert);
+  v3_out->routerstatus_list = routerstatuses;
+  /* Note: networkstatus_digest is unset; it won't get set until we actually
+   * format the vote. */
+
+  return v3_out;
+}
+
diff --git a/src/or/dirauth/shared_random.c b/src/or/dirauth/shared_random.c
index 5dee77dce9..7e49204159 100644
--- a/src/or/dirauth/shared_random.c
+++ b/src/or/dirauth/shared_random.c
@@ -91,6 +91,7 @@
 #include "shared_random.h"
 #include "config.h"
 #include "confparse.h"
+#include "dirvote_common.h"
 #include "networkstatus.h"
 #include "routerkeys.h"
 #include "router.h"
diff --git a/src/or/dirauth/shared_random_state.c b/src/or/dirauth/shared_random_state.c
index 846c3c7aa2..ac8fb5c151 100644
--- a/src/or/dirauth/shared_random_state.c
+++ b/src/or/dirauth/shared_random_state.c
@@ -14,6 +14,7 @@
 #include "shared_random.h"
 #include "config.h"
 #include "confparse.h"
+#include "dirvote_common.h"
 #include "networkstatus.h"
 #include "router.h"
 #include "shared_random_state.h"