xref: /dports/security/tor-devel/tor-0.4.7.2-alpha/src/feature/relay/router.c

/* Copyright (c) 2001 Matej Pfajfar.
 * Copyright (c) 2001-2004, Roger Dingledine.
 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 * Copyright (c) 2007-2021, The Tor Project, Inc. */
/* See LICENSE for licensing information */

#define ROUTER_PRIVATE

#include "core/or/or.h"
#include "app/config/config.h"
#include "app/config/resolve_addr.h"
#include "app/config/statefile.h"
#include "app/main/main.h"
#include "core/mainloop/connection.h"
#include "core/mainloop/mainloop.h"
#include "core/mainloop/netstatus.h"
#include "core/or/policies.h"
#include "core/or/protover.h"
#include "feature/client/transports.h"
#include "feature/control/control_events.h"
#include "feature/dirauth/process_descs.h"
#include "feature/dircache/dirserv.h"
#include "feature/dirclient/dirclient.h"
#include "feature/dircommon/directory.h"
#include "feature/dirparse/authcert_parse.h"
#include "feature/dirparse/routerparse.h"
#include "feature/dirparse/signing.h"
#include "feature/hibernate/hibernate.h"
#include "feature/keymgt/loadkey.h"
#include "feature/nodelist/authcert.h"
#include "feature/nodelist/dirlist.h"
#include "feature/nodelist/networkstatus.h"
#include "feature/nodelist/nickname.h"
#include "feature/nodelist/nodefamily.h"
#include "feature/nodelist/nodelist.h"
#include "feature/nodelist/routerlist.h"
#include "feature/nodelist/torcert.h"
#include "feature/relay/dns.h"
#include "feature/relay/relay_config.h"
#include "feature/relay/relay_find_addr.h"
#include "feature/relay/relay_periodic.h"
#include "feature/relay/router.h"
#include "feature/relay/routerkeys.h"
#include "feature/relay/routermode.h"
#include "feature/relay/selftest.h"
#include "lib/geoip/geoip.h"
#include "feature/stats/geoip_stats.h"
#include "feature/stats/bwhist.h"
#include "feature/stats/rephist.h"
#include "lib/crypt_ops/crypto_ed25519.h"
#include "lib/crypt_ops/crypto_format.h"
#include "lib/crypt_ops/crypto_init.h"
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_util.h"
#include "lib/encoding/confline.h"
#include "lib/osinfo/uname.h"
#include "lib/tls/tortls.h"
#include "lib/version/torversion.h"

#include "feature/dirauth/authmode.h"

#include "app/config/or_state_st.h"
#include "core/or/port_cfg_st.h"
#include "feature/dirclient/dir_server_st.h"
#include "feature/dircommon/dir_connection_st.h"
#include "feature/nodelist/authority_cert_st.h"
#include "feature/nodelist/extrainfo_st.h"
#include "feature/nodelist/networkstatus_st.h"
#include "feature/nodelist/node_st.h"
#include "feature/nodelist/routerinfo_st.h"
#include "feature/nodelist/routerstatus_st.h"

/**
 * \file router.c
 * \brief Miscellaneous relay functionality, including RSA key maintenance,
 * generating and uploading server descriptors, picking an address to
 * advertise, and so on.
 *
 * This module handles the job of deciding whether we are a Tor relay, and if
 * so what kind. (Mostly through functions like server_mode() that inspect an
 * or_options_t, but in some cases based on our own capabilities, such as when
 * we are deciding whether to be a directory cache in
 * router_has_bandwidth_to_be_dirserver().)
 *
 * Also in this module are the functions to generate our own routerinfo_t and
 * extrainfo_t, and to encode those to signed strings for upload to the
 * directory authorities.
 *
 * This module also handles key maintenance for RSA and Curve25519-ntor keys,
 * and for our TLS context. (These functions should eventually move to
 * routerkeys.c along with the code that handles Ed25519 keys now.)
 **/

/************************************************************/

/*****
 * Key management: ORs only.
 *****/

/** Private keys for this OR.  There is also an SSL key managed by tortls.c.
 */
static tor_mutex_t *key_lock=NULL;
static time_t onionkey_set_at=0; /**< When was onionkey last changed? */
/** Current private onionskin decryption key: used to decode CREATE cells. */
static crypto_pk_t *onionkey=NULL;
/** Previous private onionskin decryption key: used to decode CREATE cells
 * generated by clients that have an older version of our descriptor. */
static crypto_pk_t *lastonionkey=NULL;
/** Current private ntor secret key: used to perform the ntor handshake. */
static curve25519_keypair_t curve25519_onion_key;
/** Previous private ntor secret key: used to perform the ntor handshake
 * with clients that have an older version of our descriptor. */
static curve25519_keypair_t last_curve25519_onion_key;
/** Private server "identity key": used to sign directory info and TLS
 * certificates. Never changes. */
static crypto_pk_t *server_identitykey=NULL;
/** Digest of server_identitykey. */
static char server_identitykey_digest[DIGEST_LEN];
/** Private client "identity key": used to sign bridges' and clients'
 * outbound TLS certificates. Regenerated on startup and on IP address
 * change. */
static crypto_pk_t *client_identitykey=NULL;
/** Signing key used for v3 directory material; only set for authorities. */
static crypto_pk_t *authority_signing_key = NULL;
/** Key certificate to authenticate v3 directory material; only set for
 * authorities. */
static authority_cert_t *authority_key_certificate = NULL;

/** For emergency V3 authority key migration: An extra signing key that we use
 * with our old (obsolete) identity key for a while. */
static crypto_pk_t *legacy_signing_key = NULL;
/** For emergency V3 authority key migration: An extra certificate to
 * authenticate legacy_signing_key with our obsolete identity key.*/
static authority_cert_t *legacy_key_certificate = NULL;

/* (Note that v3 authorities also have a separate "authority identity key",
 * but this key is never actually loaded by the Tor process.  Instead, it's
 * used by tor-gencert to sign new signing keys and make new key
 * certificates. */

/** Indicate if the IPv6 address should be omitted from the descriptor when
 * publishing it. This can happen if the IPv4 is reachable but the
 * auto-discovered IPv6 is not. We still publish the descriptor.
 *
 * Only relays should look at this and only for their descriptor.
 *
 * XXX: The real harder fix is to never put in the routerinfo_t a non
 * reachable address and instead use the last resolved address cache to do
 * reachability test or anything that has to do with what address tor thinks
 * it has. */
static bool omit_ipv6_on_publish = false;

/** Return a readonly string with human readable description
 * of <b>err</b>.
 */
const char *
routerinfo_err_to_string(int err)
{
  switch (err) {
    case TOR_ROUTERINFO_ERROR_NO_EXT_ADDR:
      return "No known exit address yet";
    case TOR_ROUTERINFO_ERROR_CANNOT_PARSE:
      return "Cannot parse descriptor";
    case TOR_ROUTERINFO_ERROR_NOT_A_SERVER:
      return "Not running in server mode";
    case TOR_ROUTERINFO_ERROR_DIGEST_FAILED:
      return "Key digest failed";
    case TOR_ROUTERINFO_ERROR_CANNOT_GENERATE:
      return "Cannot generate descriptor";
    case TOR_ROUTERINFO_ERROR_DESC_REBUILDING:
      return "Descriptor still rebuilding - not ready yet";
    case TOR_ROUTERINFO_ERROR_INTERNAL_BUG:
      return "Internal bug, see logs for details";
  }

  log_warn(LD_BUG, "unknown routerinfo error %d - shouldn't happen", err);
  tor_assert_unreached();

  return "Unknown error";
}

/** Return true if we expect given error to be transient.
 * Return false otherwise.
 */
int
routerinfo_err_is_transient(int err)
{
  /**
   * For simplicity, we consider all errors other than
   * "not a server" transient - see discussion on
   * https://bugs.torproject.org/tpo/core/tor/27034.
   */
  return err != TOR_ROUTERINFO_ERROR_NOT_A_SERVER;
}

/** Replace the current onion key with <b>k</b>.  Does not affect
 * lastonionkey; to update lastonionkey correctly, call rotate_onion_key().
 */
static void
set_onion_key(crypto_pk_t *k)
{
  if (onionkey && crypto_pk_eq_keys(onionkey, k)) {
    /* k is already our onion key; free it and return */
    crypto_pk_free(k);
    return;
  }
  tor_mutex_acquire(key_lock);
  crypto_pk_free(onionkey);
  onionkey = k;
  tor_mutex_release(key_lock);
  mark_my_descriptor_dirty("set onion key");
}

/** Return the current onion key.  Requires that the onion key has been
 * loaded or generated. */
MOCK_IMPL(crypto_pk_t *,
get_onion_key,(void))
{
  tor_assert(onionkey);
  return onionkey;
}

/** Store a full copy of the current onion key into *<b>key</b>, and a full
 * copy of the most recent onion key into *<b>last</b>.  Store NULL into
 * a pointer if the corresponding key does not exist.
 */
void
dup_onion_keys(crypto_pk_t **key, crypto_pk_t **last)
{
  tor_assert(key);
  tor_assert(last);
  tor_mutex_acquire(key_lock);
  if (onionkey)
    *key = crypto_pk_copy_full(onionkey);
  else
    *key = NULL;
  if (lastonionkey)
    *last = crypto_pk_copy_full(lastonionkey);
  else
    *last = NULL;
  tor_mutex_release(key_lock);
}

/** Expire our old set of onion keys. This is done by setting
 * last_curve25519_onion_key and lastonionkey to all zero's and NULL
 * respectively.
 *
 * This function does not perform any grace period checks for the old onion
 * keys.
 */
void
expire_old_onion_keys(void)
{
  char *fname = NULL;

  tor_mutex_acquire(key_lock);

  /* Free lastonionkey and set it to NULL. */
  if (lastonionkey) {
    crypto_pk_free(lastonionkey);
    lastonionkey = NULL;
  }

  /* We zero out the keypair. See the fast_mem_is_zero() check made in
   * construct_ntor_key_map() below. */
  memset(&last_curve25519_onion_key, 0, sizeof(last_curve25519_onion_key));

  tor_mutex_release(key_lock);

  fname = get_keydir_fname("secret_onion_key.old");
  if (file_status(fname) == FN_FILE) {
    if (tor_unlink(fname) != 0) {
      log_warn(LD_FS, "Couldn't unlink old onion key file %s: %s",
               fname, strerror(errno));
    }
  }
  tor_free(fname);

  fname = get_keydir_fname("secret_onion_key_ntor.old");
  if (file_status(fname) == FN_FILE) {
    if (tor_unlink(fname) != 0) {
      log_warn(LD_FS, "Couldn't unlink old ntor onion key file %s: %s",
               fname, strerror(errno));
    }
  }
  tor_free(fname);
}

/** Return the current secret onion key for the ntor handshake. Must only
 * be called from the main thread. */
MOCK_IMPL(STATIC const struct curve25519_keypair_t *,
get_current_curve25519_keypair,(void))
{
  return &curve25519_onion_key;
}

/** Return a map from KEYID (the key itself) to keypairs for use in the ntor
 * handshake. Must only be called from the main thread. */
di_digest256_map_t *
construct_ntor_key_map(void)
{
  di_digest256_map_t *m = NULL;

  const uint8_t *cur_pk = curve25519_onion_key.pubkey.public_key;
  const uint8_t *last_pk = last_curve25519_onion_key.pubkey.public_key;

  if (!fast_mem_is_zero((const char *)cur_pk, CURVE25519_PUBKEY_LEN)) {
    dimap_add_entry(&m, cur_pk,
                    tor_memdup(&curve25519_onion_key,
                               sizeof(curve25519_keypair_t)));
  }
  if (!fast_mem_is_zero((const char*)last_pk, CURVE25519_PUBKEY_LEN) &&
      tor_memneq(cur_pk, last_pk, CURVE25519_PUBKEY_LEN)) {
    dimap_add_entry(&m, last_pk,
                    tor_memdup(&last_curve25519_onion_key,
                               sizeof(curve25519_keypair_t)));
  }

  return m;
}
/** Helper used to deallocate a di_digest256_map_t returned by
 * construct_ntor_key_map. */
static void
ntor_key_map_free_helper(void *arg)
{
  curve25519_keypair_t *k = arg;
  memwipe(k, 0, sizeof(*k));
  tor_free(k);
}
/** Release all storage from a keymap returned by construct_ntor_key_map. */
void
ntor_key_map_free_(di_digest256_map_t *map)
{
  if (!map)
    return;
  dimap_free(map, ntor_key_map_free_helper);
}

/** Return the time when the onion key was last set.  This is either the time
 * when the process launched, or the time of the most recent key rotation since
 * the process launched.
 */
time_t
get_onion_key_set_at(void)
{
  return onionkey_set_at;
}

/** Set the current server identity key to <b>k</b>.
 */
void
set_server_identity_key(crypto_pk_t *k)
{
  crypto_pk_free(server_identitykey);
  server_identitykey = k;
  if (crypto_pk_get_digest(server_identitykey,
                           server_identitykey_digest) < 0) {
    log_err(LD_BUG, "Couldn't compute our own identity key digest.");
    tor_assert(0);
  }
}

#ifdef TOR_UNIT_TESTS
/** Testing only -- set the server's RSA identity digest to
 * be <b>digest</b> */
void
set_server_identity_key_digest_testing(const uint8_t *digest)
{
  memcpy(server_identitykey_digest, digest, DIGEST_LEN);
}
#endif /* defined(TOR_UNIT_TESTS) */

/** Make sure that we have set up our identity keys to match or not match as
 * appropriate, and die with an assertion if we have not. */
static void
assert_identity_keys_ok(void)
{
  if (1)
    return;
  tor_assert(client_identitykey);
  if (public_server_mode(get_options())) {
    /* assert that we have set the client and server keys to be equal */
    tor_assert(server_identitykey);
    tor_assert(crypto_pk_eq_keys(client_identitykey, server_identitykey));
  } else {
    /* assert that we have set the client and server keys to be unequal */
    if (server_identitykey)
      tor_assert(!crypto_pk_eq_keys(client_identitykey, server_identitykey));
  }
}

#ifdef HAVE_MODULE_RELAY

/** Returns the current server identity key; requires that the key has
 * been set, and that we are running as a Tor server.
 */
MOCK_IMPL(crypto_pk_t *,
get_server_identity_key,(void))
{
  tor_assert(server_identitykey);
  tor_assert(server_mode(get_options()) ||
             get_options()->command == CMD_KEY_EXPIRATION);
  assert_identity_keys_ok();
  return server_identitykey;
}

#endif /* defined(HAVE_MODULE_RELAY) */

/** Return true iff we are a server and the server identity key
 * has been set. */
int
server_identity_key_is_set(void)
{
  return (server_mode(get_options()) ||
          get_options()->command == CMD_KEY_EXPIRATION) &&
         server_identitykey != NULL;
}

/** Set the current client identity key to <b>k</b>.
 */
void
set_client_identity_key(crypto_pk_t *k)
{
  crypto_pk_free(client_identitykey);
  client_identitykey = k;
}

/** Returns the current client identity key for use on outgoing TLS
 * connections; requires that the key has been set.
 */
crypto_pk_t *
get_tlsclient_identity_key(void)
{
  tor_assert(client_identitykey);
  assert_identity_keys_ok();
  return client_identitykey;
}

/** Return true iff the client identity key has been set. */
int
client_identity_key_is_set(void)
{
  return client_identitykey != NULL;
}

/** Return the key certificate for this v3 (voting) authority, or NULL
 * if we have no such certificate. */
MOCK_IMPL(authority_cert_t *,
get_my_v3_authority_cert, (void))
{
  return authority_key_certificate;
}

/** Return the v3 signing key for this v3 (voting) authority, or NULL
 * if we have no such key. */
crypto_pk_t *
get_my_v3_authority_signing_key(void)
{
  return authority_signing_key;
}

/** If we're an authority, and we're using a legacy authority identity key for
 * emergency migration purposes, return the certificate associated with that
 * key. */
authority_cert_t *
get_my_v3_legacy_cert(void)
{
  return legacy_key_certificate;
}

/** If we're an authority, and we're using a legacy authority identity key for
 * emergency migration purposes, return that key. */
crypto_pk_t *
get_my_v3_legacy_signing_key(void)
{
  return legacy_signing_key;
}

/** Replace the previous onion key with the current onion key, and generate
 * a new previous onion key.  Immediately after calling this function,
 * the OR should:
 *   - schedule all previous cpuworkers to shut down _after_ processing
 *     pending work.  (This will cause fresh cpuworkers to be generated.)
 *   - generate and upload a fresh routerinfo.
 */
void
rotate_onion_key(void)
{
  char *fname, *fname_prev;
  crypto_pk_t *prkey = NULL;
  or_state_t *state = get_or_state();
  curve25519_keypair_t new_curve25519_keypair;
  time_t now;
  fname = get_keydir_fname("secret_onion_key");
  fname_prev = get_keydir_fname("secret_onion_key.old");
  /* There isn't much point replacing an old key with an empty file */
  if (file_status(fname) == FN_FILE) {
    if (replace_file(fname, fname_prev))
      goto error;
  }
  if (!(prkey = crypto_pk_new())) {
    log_err(LD_GENERAL,"Error constructing rotated onion key");
    goto error;
  }
  if (crypto_pk_generate_key(prkey)) {
    log_err(LD_BUG,"Error generating onion key");
    goto error;
  }
  if (crypto_pk_write_private_key_to_filename(prkey, fname)) {
    log_err(LD_FS,"Couldn't write generated onion key to \"%s\".", fname);
    goto error;
  }
  tor_free(fname);
  tor_free(fname_prev);
  fname = get_keydir_fname("secret_onion_key_ntor");
  fname_prev = get_keydir_fname("secret_onion_key_ntor.old");
  if (curve25519_keypair_generate(&new_curve25519_keypair, 1) < 0)
    goto error;
  /* There isn't much point replacing an old key with an empty file */
  if (file_status(fname) == FN_FILE) {
    if (replace_file(fname, fname_prev))
      goto error;
  }
  if (curve25519_keypair_write_to_file(&new_curve25519_keypair, fname,
                                       "onion") < 0) {
    log_err(LD_FS,"Couldn't write curve25519 onion key to \"%s\".",fname);
    goto error;
  }
  log_info(LD_GENERAL, "Rotating onion key");
  tor_mutex_acquire(key_lock);
  crypto_pk_free(lastonionkey);
  lastonionkey = onionkey;
  onionkey = prkey;
  memcpy(&last_curve25519_onion_key, &curve25519_onion_key,
         sizeof(curve25519_keypair_t));
  memcpy(&curve25519_onion_key, &new_curve25519_keypair,
         sizeof(curve25519_keypair_t));
  now = time(NULL);
  state->LastRotatedOnionKey = onionkey_set_at = now;
  tor_mutex_release(key_lock);
  mark_my_descriptor_dirty("rotated onion key");
  or_state_mark_dirty(state, get_options()->AvoidDiskWrites ? now+3600 : 0);
  goto done;
 error:
  log_warn(LD_GENERAL, "Couldn't rotate onion key.");
  if (prkey)
    crypto_pk_free(prkey);
 done:
  memwipe(&new_curve25519_keypair, 0, sizeof(new_curve25519_keypair));
  tor_free(fname);
  tor_free(fname_prev);
}

/** Log greeting message that points to new relay lifecycle document the
 * first time this function has been called.
 */
static void
log_new_relay_greeting(void)
{
  static int already_logged = 0;

  if (already_logged)
    return;

  tor_log(LOG_NOTICE, LD_GENERAL, "You are running a new relay. "
         "Thanks for helping the Tor network! If you wish to know "
         "what will happen in the upcoming weeks regarding its usage, "
         "have a look at https://blog.torproject.org/blog/lifecycle-of"
         "-a-new-relay");

  already_logged = 1;
}

/** Load a curve25519 keypair from the file <b>fname</b>, writing it into
 * <b>keys_out</b>.  If the file isn't found, or is empty, and <b>generate</b>
 * is true, create a new keypair and write it into the file.  If there are
 * errors, log them at level <b>severity</b>. Generate files using <b>tag</b>
 * in their ASCII wrapper. */
static int
init_curve25519_keypair_from_file(curve25519_keypair_t *keys_out,
                                  const char *fname,
                                  int generate,
                                  int severity,
                                  const char *tag)
{
  switch (file_status(fname)) {
    case FN_DIR:
    case FN_ERROR:
      tor_log(severity, LD_FS,"Can't read key from \"%s\"", fname);
      goto error;
    /* treat empty key files as if the file doesn't exist, and, if generate
     * is set, replace the empty file in curve25519_keypair_write_to_file() */
    case FN_NOENT:
    case FN_EMPTY:
      if (generate) {
        if (!have_lockfile()) {
          if (try_locking(get_options(), 0)<0) {
            /* Make sure that --list-fingerprint only creates new keys
             * if there is no possibility for a deadlock. */
            tor_log(severity, LD_FS, "Another Tor process has locked \"%s\". "
                    "Not writing any new keys.", fname);
            /*XXXX The 'other process' might make a key in a second or two;
             * maybe we should wait for it. */
            goto error;
          }
        }
        log_info(LD_GENERAL, "No key found in \"%s\"; generating fresh key.",
                 fname);
        if (curve25519_keypair_generate(keys_out, 1) < 0)
          goto error;
        if (curve25519_keypair_write_to_file(keys_out, fname, tag)<0) {
          tor_log(severity, LD_FS,
              "Couldn't write generated key to \"%s\".", fname);
          memwipe(keys_out, 0, sizeof(*keys_out));
          goto error;
        }
      } else {
        log_info(LD_GENERAL, "No key found in \"%s\"", fname);
      }
      return 0;
    case FN_FILE:
      {
        char *tag_in=NULL;
        if (curve25519_keypair_read_from_file(keys_out, &tag_in, fname) < 0) {
          tor_log(severity, LD_GENERAL,"Error loading private key.");
          tor_free(tag_in);
          goto error;
        }
        if (!tag_in || strcmp(tag_in, tag)) {
          tor_log(severity, LD_GENERAL,"Unexpected tag %s on private key.",
              escaped(tag_in));
          tor_free(tag_in);
          goto error;
        }
        tor_free(tag_in);
        return 0;
      }
    default:
      tor_assert(0);
  }

 error:
  return -1;
}

/** Try to load the vote-signing private key and certificate for being a v3
 * directory authority, and make sure they match.  If <b>legacy</b>, load a
 * legacy key/cert set for emergency key migration; otherwise load the regular
 * key/cert set.  On success, store them into *<b>key_out</b> and
 * *<b>cert_out</b> respectively, and return 0.  On failure, return -1. */
static int
load_authority_keyset(int legacy, crypto_pk_t **key_out,
                      authority_cert_t **cert_out)
{
  int r = -1;
  char *fname = NULL, *cert = NULL;
  const char *eos = NULL;
  crypto_pk_t *signing_key = NULL;
  authority_cert_t *parsed = NULL;

  fname = get_keydir_fname(
                 legacy ? "legacy_signing_key" : "authority_signing_key");
  signing_key = init_key_from_file(fname, 0, LOG_ERR, NULL);
  if (!signing_key) {
    log_warn(LD_DIR, "No version 3 directory key found in %s", fname);
    goto done;
  }
  tor_free(fname);
  fname = get_keydir_fname(
               legacy ? "legacy_certificate" : "authority_certificate");
  cert = read_file_to_str(fname, 0, NULL);
  if (!cert) {
    log_warn(LD_DIR, "Signing key found, but no certificate found in %s",
               fname);
    goto done;
  }
  parsed = authority_cert_parse_from_string(cert, strlen(cert), &eos);
  if (!parsed) {
    log_warn(LD_DIR, "Unable to parse certificate in %s", fname);
    goto done;
  }
  if (!crypto_pk_eq_keys(signing_key, parsed->signing_key)) {
    log_warn(LD_DIR, "Stored signing key does not match signing key in "
             "certificate");
    goto done;
  }

  crypto_pk_free(*key_out);
  authority_cert_free(*cert_out);

  *key_out = signing_key;
  *cert_out = parsed;
  r = 0;
  signing_key = NULL;
  parsed = NULL;

 done:
  tor_free(fname);
  tor_free(cert);
  crypto_pk_free(signing_key);
  authority_cert_free(parsed);
  return r;
}

/** Load the v3 (voting) authority signing key and certificate, if they are
 * present.  Return -1 if anything is missing, mismatched, or unloadable;
 * return 0 on success. */
static int
init_v3_authority_keys(void)
{
  if (load_authority_keyset(0, &authority_signing_key,
                            &authority_key_certificate)<0)
    return -1;

  if (get_options()->V3AuthUseLegacyKey &&
      load_authority_keyset(1, &legacy_signing_key,
                            &legacy_key_certificate)<0)
    return -1;

  return 0;
}

/** If we're a v3 authority, check whether we have a certificate that's
 * likely to expire soon.  Warn if we do, but not too often. */
void
v3_authority_check_key_expiry(void)
{
  time_t now, expires;
  static time_t last_warned = 0;
  int badness, time_left, warn_interval;
  if (!authdir_mode_v3(get_options()) || !authority_key_certificate)
    return;

  now = time(NULL);
  expires = authority_key_certificate->expires;
  time_left = (int)( expires - now );
  if (time_left <= 0) {
    badness = LOG_ERR;
    warn_interval = 60*60;
  } else if (time_left <= 24*60*60) {
    badness = LOG_WARN;
    warn_interval = 60*60;
  } else if (time_left <= 24*60*60*7) {
    badness = LOG_WARN;
    warn_interval = 24*60*60;
  } else if (time_left <= 24*60*60*30) {
    badness = LOG_WARN;
    warn_interval = 24*60*60*5;
  } else {
    return;
  }

  if (last_warned + warn_interval > now)
    return;

  if (time_left <= 0) {
    tor_log(badness, LD_DIR, "Your v3 authority certificate has expired."
            " Generate a new one NOW.");
  } else if (time_left <= 24*60*60) {
    tor_log(badness, LD_DIR, "Your v3 authority certificate expires in %d "
            "hours; Generate a new one NOW.", time_left/(60*60));
  } else {
    tor_log(badness, LD_DIR, "Your v3 authority certificate expires in %d "
            "days; Generate a new one soon.", time_left/(24*60*60));
  }
  last_warned = now;
}

/** Get the lifetime of an onion key in days. This value is defined by the
 * network consensus parameter "onion-key-rotation-days". Always returns a
 * value between <b>MIN_ONION_KEY_LIFETIME_DAYS</b> and
 * <b>MAX_ONION_KEY_LIFETIME_DAYS</b>.
 */
static int
get_onion_key_rotation_days_(void)
{
  return networkstatus_get_param(NULL,
                                 "onion-key-rotation-days",
                                 DEFAULT_ONION_KEY_LIFETIME_DAYS,
                                 MIN_ONION_KEY_LIFETIME_DAYS,
                                 MAX_ONION_KEY_LIFETIME_DAYS);
}

/** Get the current lifetime of an onion key in seconds. This value is defined
 * by the network consensus parameter "onion-key-rotation-days", but the value
 * is converted to seconds.
 */
int
get_onion_key_lifetime(void)
{
  return get_onion_key_rotation_days_()*24*60*60;
}

/** Get the grace period of an onion key in seconds. This value is defined by
 * the network consensus parameter "onion-key-grace-period-days", but the value
 * is converted to seconds.
 */
int
get_onion_key_grace_period(void)
{
  int grace_period;
  grace_period = networkstatus_get_param(NULL,
                                         "onion-key-grace-period-days",
                                         DEFAULT_ONION_KEY_GRACE_PERIOD_DAYS,
                                         MIN_ONION_KEY_GRACE_PERIOD_DAYS,
                                         get_onion_key_rotation_days_());
  return grace_period*24*60*60;
}

/** Set up Tor's TLS contexts, based on our configuration and keys. Return 0
 * on success, and -1 on failure. */
int
router_initialize_tls_context(void)
{
  unsigned int flags = 0;
  const or_options_t *options = get_options();
  int lifetime = options->SSLKeyLifetime;
  if (public_server_mode(options))
    flags |= TOR_TLS_CTX_IS_PUBLIC_SERVER;
  if (!lifetime) { /* we should guess a good ssl cert lifetime */

    /* choose between 5 and 365 days, and round to the day */
    unsigned int five_days = 5*24*3600;
    unsigned int one_year = 365*24*3600;
    lifetime = crypto_rand_int_range(five_days, one_year);
    lifetime -= lifetime % (24*3600);

    if (crypto_rand_int(2)) {
      /* Half the time we expire at midnight, and half the time we expire
       * one second before midnight. (Some CAs wobble their expiry times a
       * bit in practice, perhaps to reduce collision attacks; see ticket
       * 8443 for details about observed certs in the wild.) */
      lifetime--;
    }
  }

  /* It's ok to pass lifetime in as an unsigned int, since
   * config_parse_interval() checked it. */
  return tor_tls_context_init(flags,
                              get_tlsclient_identity_key(),
                              server_mode(options) ?
                              get_server_identity_key() : NULL,
                              (unsigned int)lifetime);
}

/** Announce URL to bridge status page. */
STATIC void
router_announce_bridge_status_page(void)
{
  char fingerprint[FINGERPRINT_LEN + 1];

  if (crypto_pk_get_hashed_fingerprint(get_server_identity_key(),
                                       fingerprint) < 0) {
    // LCOV_EXCL_START
    log_err(LD_GENERAL, "Unable to compute bridge fingerprint");
    return;
    // LCOV_EXCL_STOP
  }

  log_notice(LD_GENERAL, "You can check the status of your bridge relay at "
                         "https://bridges.torproject.org/status?id=%s",
                         fingerprint);
}

/** Compute fingerprint (or hashed fingerprint if hashed is 1) and write
 * it to 'fingerprint' (or 'hashed-fingerprint'). Return 0 on success, or
 * -1 if Tor should die,
 */
STATIC int
router_write_fingerprint(int hashed, int ed25519_identity)
{
  char *keydir = NULL;
  const char *fname = hashed ? "hashed-fingerprint" :
                      (ed25519_identity ? "fingerprint-ed25519" :
                                          "fingerprint");
  char fingerprint[FINGERPRINT_LEN+1];
  const or_options_t *options = get_options();
  char *fingerprint_line = NULL;
  int result = -1;

  keydir = get_datadir_fname(fname);
  log_info(LD_GENERAL,"Dumping %s%s to \"%s\"...", hashed ? "hashed " : "",
           ed25519_identity ? "ed25519 identity" : "fingerprint", keydir);

  if (ed25519_identity) { /* ed25519 identity */
    digest256_to_base64(fingerprint, (const char *)
                                     get_master_identity_key()->pubkey);
  } else { /* RSA identity */
    if (!hashed) {
      if (crypto_pk_get_fingerprint(get_server_identity_key(),
                                    fingerprint, 0) < 0) {
        log_err(LD_GENERAL,"Error computing fingerprint");
        goto done;
      }
    } else {
      if (crypto_pk_get_hashed_fingerprint(get_server_identity_key(),
                                           fingerprint) < 0) {
        log_err(LD_GENERAL,"Error computing hashed fingerprint");
        goto done;
      }
    }
  }

  tor_asprintf(&fingerprint_line, "%s %s\n", options->Nickname, fingerprint);

  /* Check whether we need to write the (hashed-)fingerprint file. */
  if (write_str_to_file_if_not_equal(keydir, fingerprint_line)) {
    log_err(LD_FS, "Error writing %s%s line to file",
            hashed ? "hashed " : "",
            ed25519_identity ? "ed25519 identity" : "fingerprint");
    goto done;
  }

  log_notice(LD_GENERAL, "Your Tor %s identity key %s fingerprint is '%s %s'",
             hashed ? "bridge's hashed" : "server's",
             ed25519_identity ? "ed25519" : "",
             options->Nickname, fingerprint);

  result = 0;
 done:
  tor_free(keydir);
  tor_free(fingerprint_line);
  return result;
}

static int
init_keys_common(void)
{
  if (!key_lock)
    key_lock = tor_mutex_new();

  return 0;
}

int
init_keys_client(void)
{
  crypto_pk_t *prkey;
  if (init_keys_common() < 0)
    return -1;

  if (!(prkey = crypto_pk_new()))
    return -1;
  if (crypto_pk_generate_key(prkey)) {
    crypto_pk_free(prkey);
    return -1;
  }
  set_client_identity_key(prkey);
  /* Create a TLS context. */
  if (router_initialize_tls_context() < 0) {
    log_err(LD_GENERAL,"Error creating TLS context for Tor client.");
    return -1;
  }
  return 0;
}

/** Initialize all OR private keys, and the TLS context, as necessary.
 * On OPs, this only initializes the tls context. Return 0 on success,
 * or -1 if Tor should die.
 */
int
init_keys(void)
{
  char *keydir;
  const char *mydesc;
  crypto_pk_t *prkey;
  char digest[DIGEST_LEN];
  char v3_digest[DIGEST_LEN];
  const or_options_t *options = get_options();
  dirinfo_type_t type;
  time_t now = time(NULL);
  dir_server_t *ds;
  int v3_digest_set = 0;
  authority_cert_t *cert = NULL;

  /* OP's don't need persistent keys; just make up an identity and
   * initialize the TLS context. */
  if (!server_mode(options) && !(options->command == CMD_KEY_EXPIRATION)) {
    return init_keys_client();
  }
  if (init_keys_common() < 0)
    return -1;

  if (create_keys_directory(options) < 0)
    return -1;

  /* 1a. Read v3 directory authority key/cert information. */
  memset(v3_digest, 0, sizeof(v3_digest));
  if (authdir_mode_v3(options)) {
    if (init_v3_authority_keys()<0) {
      log_err(LD_GENERAL, "We're configured as a V3 authority, but we "
              "were unable to load our v3 authority keys and certificate! "
              "Use tor-gencert to generate them. Dying.");
      return -1;
    }
    cert = get_my_v3_authority_cert();
    if (cert) {
      if (crypto_pk_get_digest(get_my_v3_authority_cert()->identity_key,
                               v3_digest) < 0) {
        log_err(LD_BUG, "Couldn't compute my v3 authority identity key "
                "digest.");
        return -1;
      }
      v3_digest_set = 1;
    }
  }

  /* 1b. Read identity key. Make it if none is found. */
  keydir = get_keydir_fname("secret_id_key");
  log_info(LD_GENERAL,"Reading/making identity key \"%s\"...",keydir);
  bool created = false;
  prkey = init_key_from_file(keydir, 1, LOG_ERR, &created);
  tor_free(keydir);
  if (!prkey) return -1;
  if (created)
    log_new_relay_greeting();
  set_server_identity_key(prkey);

  /* 1c. If we are configured as a bridge, generate a client key;
   * otherwise, set the server identity key as our client identity
   * key. */
  if (public_server_mode(options)) {
    set_client_identity_key(crypto_pk_dup_key(prkey)); /* set above */
  } else {
    if (!(prkey = crypto_pk_new()))
      return -1;
    if (crypto_pk_generate_key(prkey)) {
      crypto_pk_free(prkey);
      return -1;
    }
    set_client_identity_key(prkey);
  }

  /* 1d. Load all ed25519 keys */
  const int new_signing_key = load_ed_keys(options,now);
  if (new_signing_key < 0)
    return -1;

  /* 2. Read onion key.  Make it if none is found. */
  keydir = get_keydir_fname("secret_onion_key");
  log_info(LD_GENERAL,"Reading/making onion key \"%s\"...",keydir);
  prkey = init_key_from_file(keydir, 1, LOG_ERR, &created);
  if (created)
    log_new_relay_greeting();
  tor_free(keydir);
  if (!prkey) return -1;
  set_onion_key(prkey);
  if (options->command == CMD_RUN_TOR) {
    /* only mess with the state file if we're actually running Tor */
    or_state_t *state = get_or_state();
    if (state->LastRotatedOnionKey > 100 && state->LastRotatedOnionKey < now) {
      /* We allow for some parsing slop, but we don't want to risk accepting
       * values in the distant future.  If we did, we might never rotate the
       * onion key. */
      onionkey_set_at = state->LastRotatedOnionKey;
    } else {
      /* We have no LastRotatedOnionKey set; either we just created the key
       * or it's a holdover from 0.1.2.4-alpha-dev or earlier.  In either case,
       * start the clock ticking now so that we will eventually rotate it even
       * if we don't stay up for the full lifetime of an onion key. */
      state->LastRotatedOnionKey = onionkey_set_at = now;
      or_state_mark_dirty(state, options->AvoidDiskWrites ?
                                   time(NULL)+3600 : 0);
    }
  }

  keydir = get_keydir_fname("secret_onion_key.old");
  if (!lastonionkey && file_status(keydir) == FN_FILE) {
    /* Load keys from non-empty files only.
     * Missing old keys won't be replaced with freshly generated keys. */
    prkey = init_key_from_file(keydir, 0, LOG_ERR, 0);
    if (prkey)
      lastonionkey = prkey;
  }
  tor_free(keydir);

  {
    /* 2b. Load curve25519 onion keys. */
    int r;
    keydir = get_keydir_fname("secret_onion_key_ntor");
    r = init_curve25519_keypair_from_file(&curve25519_onion_key,
                                          keydir, 1, LOG_ERR, "onion");
    tor_free(keydir);
    if (r<0)
      return -1;

    keydir = get_keydir_fname("secret_onion_key_ntor.old");
    if (fast_mem_is_zero((const char *)
                           last_curve25519_onion_key.pubkey.public_key,
                        CURVE25519_PUBKEY_LEN) &&
        file_status(keydir) == FN_FILE) {
      /* Load keys from non-empty files only.
       * Missing old keys won't be replaced with freshly generated keys. */
      init_curve25519_keypair_from_file(&last_curve25519_onion_key,
                                        keydir, 0, LOG_ERR, "onion");
    }
    tor_free(keydir);
  }

  /* 3. Initialize link key and TLS context. */
  if (router_initialize_tls_context() < 0) {
    log_err(LD_GENERAL,"Error initializing TLS context");
    return -1;
  }

  /* 3b. Get an ed25519 link certificate.  Note that we need to do this
   * after we set up the TLS context */
  if (generate_ed_link_cert(options, now, new_signing_key > 0) < 0) {
    log_err(LD_GENERAL,"Couldn't make link cert");
    return -1;
  }

  /* 4. Build our router descriptor. */
  /* Must be called after keys are initialized. */
  mydesc = router_get_my_descriptor();
  if (authdir_mode_v3(options)) {
    const char *m = NULL;
    routerinfo_t *ri;
    /* We need to add our own fingerprint and ed25519 key so it gets
     * recognized. */
    if (dirserv_add_own_fingerprint(get_server_identity_key(),
                                    get_master_identity_key())) {
      log_err(LD_GENERAL,"Error adding own fingerprint to set of relays");
      return -1;
    }
    if (mydesc) {
      was_router_added_t added;
      ri = router_parse_entry_from_string(mydesc, NULL, 1, 0, NULL, NULL);
      if (!ri) {
        log_err(LD_GENERAL,"Generated a routerinfo we couldn't parse.");
        return -1;
      }
      added = dirserv_add_descriptor(ri, &m, "self");
      if (!WRA_WAS_ADDED(added)) {
        if (!WRA_WAS_OUTDATED(added)) {
          log_err(LD_GENERAL, "Unable to add own descriptor to directory: %s",
                  m?m:"<unknown error>");
          return -1;
        } else {
          /* If the descriptor was outdated, that's ok. This can happen
           * when some config options are toggled that affect workers, but
           * we don't really need new keys yet so the descriptor doesn't
           * change and the old one is still fresh. */
          log_info(LD_GENERAL, "Couldn't add own descriptor to directory "
                   "after key init: %s This is usually not a problem.",
                   m?m:"<unknown error>");
        }
      }
    }
  }

  /* 5. Dump fingerprint, ed25519 identity and possibly hashed fingerprint
   * to files. */
  if (router_write_fingerprint(0, 0)) {
    log_err(LD_FS, "Error writing fingerprint to file");
    return -1;
  }
  if (!public_server_mode(options) && router_write_fingerprint(1, 0)) {
    log_err(LD_FS, "Error writing hashed fingerprint to file");
    return -1;
  }
  if (router_write_fingerprint(0, 1)) {
    log_err(LD_FS, "Error writing ed25519 identity to file");
    return -1;
  }

  /* Display URL to bridge status page. */
  if (! public_server_mode(options))
    router_announce_bridge_status_page();

  if (!authdir_mode(options))
    return 0;
  /* 6. [authdirserver only] load approved-routers file */
  if (dirserv_load_fingerprint_file() < 0) {
    log_err(LD_GENERAL,"Error loading fingerprints");
    return -1;
  }
  /* 6b. [authdirserver only] add own key to approved directories. */
  crypto_pk_get_digest(get_server_identity_key(), digest);
  type = ((options->V3AuthoritativeDir ?
               (V3_DIRINFO|MICRODESC_DIRINFO|EXTRAINFO_DIRINFO) : NO_DIRINFO) |
          (options->BridgeAuthoritativeDir ? BRIDGE_DIRINFO : NO_DIRINFO));

  ds = router_get_trusteddirserver_by_digest(digest);
  if (!ds) {
    tor_addr_port_t ipv6_orport;
    routerconf_find_ipv6_or_ap(options, &ipv6_orport);
    ds = trusted_dir_server_new(options->Nickname, NULL,
                                routerconf_find_dir_port(options, 0),
                                routerconf_find_or_port(options,AF_INET),
                                &ipv6_orport,
                                digest,
                                v3_digest,
                                type, 0.0);
    if (!ds) {
      log_err(LD_GENERAL,"We want to be a directory authority, but we "
              "couldn't add ourselves to the authority list. Failing.");
      return -1;
    }
    dir_server_add(ds);
  }
  if (ds->type != type) {
    log_warn(LD_DIR,  "Configured authority type does not match authority "
             "type in DirAuthority list.  Adjusting. (%d v %d)",
             type, ds->type);
    ds->type = type;
  }
  if (v3_digest_set && (ds->type & V3_DIRINFO) &&
      tor_memneq(v3_digest, ds->v3_identity_digest, DIGEST_LEN)) {
    log_warn(LD_DIR, "V3 identity key does not match identity declared in "
             "DirAuthority line.  Adjusting.");
    memcpy(ds->v3_identity_digest, v3_digest, DIGEST_LEN);
  }

  if (cert) { /* add my own cert to the list of known certs */
    log_info(LD_DIR, "adding my own v3 cert");
    if (trusted_dirs_load_certs_from_string(
                      cert->cache_info.signed_descriptor_body,
                      TRUSTED_DIRS_CERTS_SRC_SELF, 0,
                      NULL)<0) {
      log_warn(LD_DIR, "Unable to parse my own v3 cert! Failing.");
      return -1;
    }
  }

  return 0; /* success */
}

/** The lower threshold of remaining bandwidth required to advertise (or
 * automatically provide) directory services */
/* XXX Should this be increased? */
#define MIN_BW_TO_ADVERTISE_DIRSERVER 51200

/** Return true iff we have enough configured bandwidth to advertise or
 * automatically provide directory services from cache directory
 * information. */
int
router_has_bandwidth_to_be_dirserver(const or_options_t *options)
{
  if (options->BandwidthRate < MIN_BW_TO_ADVERTISE_DIRSERVER) {
    return 0;
  }
  if (options->RelayBandwidthRate > 0 &&
      options->RelayBandwidthRate < MIN_BW_TO_ADVERTISE_DIRSERVER) {
    return 0;
  }
  return 1;
}

/** Helper: Return 1 if we have sufficient resources for serving directory
 * requests, return 0 otherwise.
 * dir_port is either 0 or the configured DirPort number.
 * If AccountingMax is set less than our advertised bandwidth, then don't
 * serve requests. Likewise, if our advertised bandwidth is less than
 * MIN_BW_TO_ADVERTISE_DIRSERVER, don't bother trying to serve requests.
 */
static int
router_should_be_dirserver(const or_options_t *options, int dir_port)
{
  static int advertising=1; /* start out assuming we will advertise */
  int new_choice=1;
  const char *reason = NULL;

  if (accounting_is_enabled(options) &&
    get_options()->AccountingRule != ACCT_IN) {
    /* Don't spend bytes for directory traffic if we could end up hibernating,
     * but allow DirPort otherwise. Some relay operators set AccountingMax
     * because they're confused or to get statistics. Directory traffic has a
     * much larger effect on output than input so there is no reason to turn it
     * off if using AccountingRule in. */
    int interval_length = accounting_get_interval_length();
    uint32_t effective_bw = relay_get_effective_bwrate(options);
    uint64_t acc_bytes;
    if (!interval_length) {
      log_warn(LD_BUG, "An accounting interval is not allowed to be zero "
                       "seconds long. Raising to 1.");
      interval_length = 1;
    }
    log_info(LD_GENERAL, "Calculating whether to advertise %s: effective "
                         "bwrate: %u, AccountingMax: %"PRIu64", "
                         "accounting interval length %d",
                         dir_port ? "dirport" : "begindir",
                         effective_bw, (options->AccountingMax),
                         interval_length);

    acc_bytes = options->AccountingMax;
    if (get_options()->AccountingRule == ACCT_SUM)
      acc_bytes /= 2;
    if (effective_bw >=
        acc_bytes / interval_length) {
      new_choice = 0;
      reason = "AccountingMax enabled";
    }
  } else if (! router_has_bandwidth_to_be_dirserver(options)) {
    /* if we're advertising a small amount */
    new_choice = 0;
    reason = "BandwidthRate under 50KB";
  }

  if (advertising != new_choice) {
    if (new_choice == 1) {
      if (dir_port > 0)
        log_notice(LD_DIR, "Advertising DirPort as %d", dir_port);
      else
        log_notice(LD_DIR, "Advertising directory service support");
    } else {
      tor_assert(reason);
      log_notice(LD_DIR, "Not advertising Dir%s (Reason: %s)",
                 dir_port ? "Port" : "ectory Service support", reason);
    }
    advertising = new_choice;
  }

  return advertising;
}

/** Look at a variety of factors, and return 0 if we don't want to
 * advertise the fact that we have a DirPort open or begindir support, else
 * return 1.
 *
 * Where dir_port or supports_tunnelled_dir_requests are not relevant, they
 * must be 0.
 *
 * Log a helpful message if we change our mind about whether to publish.
 */
static int
decide_to_advertise_dir_impl(const or_options_t *options,
                             uint16_t dir_port,
                             int supports_tunnelled_dir_requests)
{
  /* Part one: reasons to publish or not publish that aren't
   * worth mentioning to the user, either because they're obvious
   * or because they're normal behavior. */

  /* short circuit the rest of the function */
  if (!dir_port && !supports_tunnelled_dir_requests)
    return 0;
  if (authdir_mode(options)) /* always publish */
    return 1;
  if (net_is_disabled())
    return 0;
  if (dir_port && !routerconf_find_dir_port(options, dir_port))
    return 0;
  if (supports_tunnelled_dir_requests &&
      !routerconf_find_or_port(options, AF_INET))
    return 0;

  /* Part two: consider config options that could make us choose to
   * publish or not publish that the user might find surprising. */
  return router_should_be_dirserver(options, dir_port);
}

/** Front-end to decide_to_advertise_dir_impl(): return 0 if we don't want to
 * advertise the fact that we have a DirPort open, else return the
 * DirPort we want to advertise.
 */
int
router_should_advertise_dirport(const or_options_t *options, uint16_t dir_port)
{
  /* Only authorities should advertise a DirPort now. */
  return authdir_mode(options) ? dir_port : 0;
}

/** Front-end to decide_to_advertise_dir_impl(): return 0 if we don't want to
 * advertise the fact that we support begindir requests, else return 1.
 */
static int
router_should_advertise_begindir(const or_options_t *options,
                             int supports_tunnelled_dir_requests)
{
  /* dir_port is not relevant, pass 0 */
  return decide_to_advertise_dir_impl(options, 0,
                                      supports_tunnelled_dir_requests);
}

/** Return true iff the combination of options in <b>options</b> and parameters
 * in the consensus mean that we don't want to allow exits from circuits
 * we got from addresses not known to be servers. */
int
should_refuse_unknown_exits(const or_options_t *options)
{
  if (options->RefuseUnknownExits != -1) {
    return options->RefuseUnknownExits;
  } else {
    return networkstatus_get_param(NULL, "refuseunknownexits", 1, 0, 1);
  }
}

/**
 * If true, then we will publish our descriptor even if our own IPv4 ORPort
 * seems to be unreachable.
 **/
static bool publish_even_when_ipv4_orport_unreachable = false;
/**
 * If true, then we will publish our descriptor even if our own IPv6 ORPort
 * seems to be unreachable.
 **/
static bool publish_even_when_ipv6_orport_unreachable = false;

/** Decide if we're a publishable server. We are a publishable server if:
 * - We don't have the ClientOnly option set
 * and
 * - We have the PublishServerDescriptor option set to non-empty
 * and
 * - We have ORPort set
 * and
 * - We believe our ORPort and DirPort (if present) are reachable from
 *   the outside; or
 * - We believe our ORPort is reachable from the outside, and we can't
 *   check our DirPort because the consensus has no exits; or
 * - We are an authoritative directory server.
 */
static int
decide_if_publishable_server(void)
{
  const or_options_t *options = get_options();

  if (options->ClientOnly)
    return 0;
  if (options->PublishServerDescriptor_ == NO_DIRINFO)
    return 0;
  if (!server_mode(options))
    return 0;
  if (authdir_mode(options))
    return 1;
  if (!routerconf_find_or_port(options, AF_INET))
    return 0;
  if (!router_orport_seems_reachable(options, AF_INET)) {
    // We have an ipv4 orport, and it doesn't seem reachable.
    if (!publish_even_when_ipv4_orport_unreachable) {
      return 0;
    }
  }
  /* We could be flagged to omit the IPv6 and if so, don't check for
   * reachability on the IPv6. This can happen if the address was
   * auto-discovered but turns out to be non reachable. */
  if (!omit_ipv6_on_publish &&
      !router_orport_seems_reachable(options, AF_INET6)) {
    // We have an ipv6 orport, and it doesn't seem reachable.
    if (!publish_even_when_ipv6_orport_unreachable) {
      return 0;
    }
  }
  if (router_have_consensus_path() == CONSENSUS_PATH_INTERNAL) {
    /* All set: there are no exits in the consensus (maybe this is a tiny
     * test network), so we can't check our DirPort reachability. */
    return 1;
  } else {
    return router_dirport_seems_reachable(options);
  }
}

/** Initiate server descriptor upload as reasonable (if server is publishable,
 * etc).  <b>force</b> is as for router_upload_dir_desc_to_dirservers.
 *
 * We need to rebuild the descriptor if it's dirty even if we're not
 * uploading, because our reachability testing *uses* our descriptor to
 * determine what IP address and ports to test.
 */
void
consider_publishable_server(int force)
{
  int rebuilt;

  if (!server_mode(get_options()))
    return;

  rebuilt = router_rebuild_descriptor(0);
  if (rebuilt && decide_if_publishable_server()) {
    set_server_advertised(1);
    router_upload_dir_desc_to_dirservers(force);
  } else {
    set_server_advertised(0);
  }
}

/** Return the port of the first active listener of type
 *  <b>listener_type</b>. Returns 0 if no port is found. */
/** XXX not a very good interface. it's not reliable when there are
    multiple listeners. */
uint16_t
router_get_active_listener_port_by_type_af(int listener_type,
                                           sa_family_t family)
{
  /* Iterate all connections, find one of the right kind and return
     the port. Not very sophisticated or fast, but effective. */
  smartlist_t *conns = get_connection_array();
  SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
    if (conn->type == listener_type && !conn->marked_for_close &&
        conn->socket_family == family) {
      return conn->port;
    }
  } SMARTLIST_FOREACH_END(conn);

  return 0;
}

/** Return the port that we should advertise as our ORPort in a given address
 * family; this is either the one configured in the ORPort option, or the one
 * we actually bound to if ORPort is "auto". Returns 0 if no port is found. */
uint16_t
routerconf_find_or_port(const or_options_t *options,
                              sa_family_t family)
{
  int port = portconf_get_first_advertised_port(CONN_TYPE_OR_LISTENER,
                                                  family);
  (void)options;

  /* If the port is in 'auto' mode, we have to use
     router_get_listener_port_by_type(). */
  if (port == CFG_AUTO_PORT)
    return router_get_active_listener_port_by_type_af(CONN_TYPE_OR_LISTENER,
                                                      family);

  return port;
}

/** As routerconf_find_or_port(), but returns the IPv6 address and
 *  port in ipv6_ap_out, which must not be NULL. Returns a null address and
 * zero port, if no ORPort is found. */
void
routerconf_find_ipv6_or_ap(const or_options_t *options,
                                 tor_addr_port_t *ipv6_ap_out)
{
  /* Bug in calling function, we can't return a sensible result, and it
   * shouldn't use the NULL pointer once we return. */
  tor_assert(ipv6_ap_out);

  /* If there is no valid IPv6 ORPort, return a null address and port. */
  tor_addr_make_null(&ipv6_ap_out->addr, AF_INET6);
  ipv6_ap_out->port = 0;

  const tor_addr_t *addr = portconf_get_first_advertised_addr(
                                                      CONN_TYPE_OR_LISTENER,
                                                      AF_INET6);
  const uint16_t port = routerconf_find_or_port(options,
                                                      AF_INET6);

  if (!addr || port == 0) {
    log_debug(LD_CONFIG, "There is no advertised IPv6 ORPort.");
    return;
  }

  /* If the relay is configured using the default authorities, disallow
   * internal IPs. Otherwise, allow them. For IPv4 ORPorts and DirPorts,
   * this check is done in resolve_my_address(). See #33681. */
  const int default_auth = using_default_dir_authorities(options);
  if (tor_addr_is_internal(addr, 0) && default_auth) {
    log_warn(LD_CONFIG,
             "Unable to use configured IPv6 ORPort \"%s\" in a "
             "descriptor. Skipping it. "
             "Try specifying a globally reachable address explicitly.",
             fmt_addrport(addr, port));
    return;
  }

  tor_addr_copy(&ipv6_ap_out->addr, addr);
  ipv6_ap_out->port = port;
}

/** Returns true if this router has an advertised IPv6 ORPort. */
bool
routerconf_has_ipv6_orport(const or_options_t *options)
{
  /* What we want here is to learn if we have configured an IPv6 ORPort.
   * Remember, ORPort can listen on [::] and thus consider internal by
   * router_get_advertised_ipv6_or_ap() since we do _not_ want to advertise
   * such address. */
  const tor_addr_t *addr =
    portconf_get_first_advertised_addr(CONN_TYPE_OR_LISTENER, AF_INET6);
  const uint16_t port =
    routerconf_find_or_port(options, AF_INET6);

  return tor_addr_port_is_valid(addr, port, 1);
}

/** Returns true if this router can extend over IPv6.
 *
 * This check should only be performed by relay extend code.
 *
 * Clients should check if relays can initiate and accept IPv6 extends using
 * node_supports_initiating_ipv6_extends() and
 * node_supports_accepting_ipv6_extends().
 *
 * As with other extends, relays should assume the client has already
 * performed the relevant checks for the next hop. (Otherwise, relays that
 * have just added IPv6 ORPorts won't be able to self-test those ORPorts.)
 *
 * Accepting relays don't need to perform any IPv6-specific checks before
 * accepting a connection, because having an IPv6 ORPort implies support for
 * the relevant protocol version.
 */
MOCK_IMPL(bool,
router_can_extend_over_ipv6,(const or_options_t *options))
{
  /* We might add some extra checks here, such as ExtendAllowIPv6Addresses
  * from ticket 33818. */
  return routerconf_has_ipv6_orport(options);
}

/** Return the port that we should advertise as our DirPort;
 * this is one of three possibilities:
 * The one that is passed as <b>dirport</b> if the DirPort option is 0, or
 * the one configured in the DirPort option,
 * or the one we actually bound to if DirPort is "auto". */
uint16_t
routerconf_find_dir_port(const or_options_t *options, uint16_t dirport)
{
  int dirport_configured = portconf_get_primary_dir_port();
  (void)options;

  if (!dirport_configured)
    return dirport;

  if (dirport_configured == CFG_AUTO_PORT)
    return router_get_active_listener_port_by_type_af(CONN_TYPE_DIR_LISTENER,
                                                      AF_INET);

  return dirport_configured;
}

/*
 * OR descriptor generation.
 */

/** My routerinfo. */
static routerinfo_t *desc_routerinfo = NULL;
/** My extrainfo */
static extrainfo_t *desc_extrainfo = NULL;
/** Why did we most recently decide to regenerate our descriptor?  Used to
 * tell the authorities why we're sending it to them. */
static const char *desc_gen_reason = "uninitialized reason";
/** Since when has our descriptor been "clean"?  0 if we need to regenerate it
 * now. */
STATIC time_t desc_clean_since = 0;
/** Why did we mark the descriptor dirty? */
STATIC const char *desc_dirty_reason = "Tor just started";
/** Boolean: do we need to regenerate the above? */
static int desc_needs_upload = 0;

/** OR only: If <b>force</b> is true, or we haven't uploaded this
 * descriptor successfully yet, try to upload our signed descriptor to
 * all the directory servers we know about.
 */
void
router_upload_dir_desc_to_dirservers(int force)
{
  const routerinfo_t *ri;
  extrainfo_t *ei;
  char *msg;
  size_t desc_len, extra_len = 0, total_len;
  dirinfo_type_t auth = get_options()->PublishServerDescriptor_;

  ri = router_get_my_routerinfo();
  if (!ri) {
    log_info(LD_GENERAL, "No descriptor; skipping upload");
    return;
  }
  ei = router_get_my_extrainfo();
  if (auth == NO_DIRINFO)
    return;
  if (!force && !desc_needs_upload)
    return;

  log_info(LD_OR, "Uploading relay descriptor to directory authorities%s",
           force ? " (forced)" : "");

  desc_needs_upload = 0;

  desc_len = ri->cache_info.signed_descriptor_len;
  extra_len = ei ? ei->cache_info.signed_descriptor_len : 0;
  total_len = desc_len + extra_len + 1;
  msg = tor_malloc(total_len);
  memcpy(msg, ri->cache_info.signed_descriptor_body, desc_len);
  if (ei) {
    memcpy(msg+desc_len, ei->cache_info.signed_descriptor_body, extra_len);
  }
  msg[desc_len+extra_len] = 0;

  directory_post_to_dirservers(DIR_PURPOSE_UPLOAD_DIR,
                               (auth & BRIDGE_DIRINFO) ?
                                 ROUTER_PURPOSE_BRIDGE :
                                 ROUTER_PURPOSE_GENERAL,
                               auth, msg, desc_len, extra_len);
  tor_free(msg);
}

/** OR only: Check whether my exit policy says to allow connection to
 * conn.  Return 0 if we accept; non-0 if we reject.
 */
int
router_compare_to_my_exit_policy(const tor_addr_t *addr, uint16_t port)
{
  const routerinfo_t *me = router_get_my_routerinfo();
  if (!me) /* make sure routerinfo exists */
    return -1;

  /* make sure it's resolved to something. this way we can't get a
     'maybe' below. */
  if (tor_addr_is_null(addr))
    return -1;

  /* look at router_get_my_routerinfo()->exit_policy for both the v4 and the
   * v6 policies.  The exit_policy field in router_get_my_routerinfo() is a
   * bit unusual, in that it contains IPv6 and IPv6 entries.  We don't want to
   * look at router_get_my_routerinfo()->ipv6_exit_policy, since that's a port
   * summary. */
  if ((tor_addr_family(addr) == AF_INET ||
       tor_addr_family(addr) == AF_INET6)) {
    return compare_tor_addr_to_addr_policy(addr, port,
                               me->exit_policy) != ADDR_POLICY_ACCEPTED;
#if 0
  } else if (tor_addr_family(addr) == AF_INET6) {
    return get_options()->IPv6Exit &&
      desc_routerinfo->ipv6_exit_policy &&
      compare_tor_addr_to_short_policy(addr, port,
                               me->ipv6_exit_policy) != ADDR_POLICY_ACCEPTED;
#endif /* 0 */
  } else {
    return -1;
  }
}

/** Return true iff my exit policy is reject *:*.  Return -1 if we don't
 * have a descriptor */
MOCK_IMPL(int,
router_my_exit_policy_is_reject_star,(void))
{
  const routerinfo_t *me = router_get_my_routerinfo();
  if (!me) /* make sure routerinfo exists */
    return -1;

  return me->policy_is_reject_star;
}

/** Return true iff I'm a server and <b>digest</b> is equal to
 * my server identity key digest. */
int
router_digest_is_me(const char *digest)
{
  return (server_identitykey &&
          tor_memeq(server_identitykey_digest, digest, DIGEST_LEN));
}

/** Return my identity digest. */
const uint8_t *
router_get_my_id_digest(void)
{
  return (const uint8_t *)server_identitykey_digest;
}

/** Return true iff I'm a server and <b>digest</b> is equal to
 * my identity digest. */
int
router_extrainfo_digest_is_me(const char *digest)
{
  extrainfo_t *ei = router_get_my_extrainfo();
  if (!ei)
    return 0;

  return tor_memeq(digest,
                 ei->cache_info.signed_descriptor_digest,
                 DIGEST_LEN);
}

/** A wrapper around router_digest_is_me(). */
int
router_is_me(const routerinfo_t *router)
{
  return router_digest_is_me(router->cache_info.identity_digest);
}

/**
 * Return true if we are a server, and if @a addr is an address we are
 * currently publishing (or trying to publish) in our descriptor.
 * Return false otherwise.
 **/
bool
router_addr_is_my_published_addr(const tor_addr_t *addr)
{
  IF_BUG_ONCE(!addr)
    return false;

  const routerinfo_t *me = router_get_my_routerinfo();
  if (!me)
    return false;

  switch (tor_addr_family(addr)) {
  case AF_INET:
    return tor_addr_eq(addr, &me->ipv4_addr);
  case AF_INET6:
    return tor_addr_eq(addr, &me->ipv6_addr);
  default:
    return false;
  }
}

/** Return a routerinfo for this OR, rebuilding a fresh one if
 * necessary.  Return NULL on error, or if called on an OP. */
MOCK_IMPL(const routerinfo_t *,
router_get_my_routerinfo,(void))
{
  return router_get_my_routerinfo_with_err(NULL);
}

/** Return routerinfo of this OR. Rebuild it from
 * scratch if needed. Set <b>*err</b> to 0 on success or to
 * appropriate TOR_ROUTERINFO_ERROR_* value on failure.
 */
MOCK_IMPL(const routerinfo_t *,
router_get_my_routerinfo_with_err,(int *err))
{
  if (!server_mode(get_options())) {
    if (err)
      *err = TOR_ROUTERINFO_ERROR_NOT_A_SERVER;

    return NULL;
  }

  if (!desc_routerinfo) {
    if (err)
      *err = TOR_ROUTERINFO_ERROR_DESC_REBUILDING;

    return NULL;
  }

  if (err)
    *err = 0;

  return desc_routerinfo;
}

/** OR only: Return a signed server descriptor for this OR, rebuilding a fresh
 * one if necessary.  Return NULL on error.
 */
const char *
router_get_my_descriptor(void)
{
  const char *body;
  const routerinfo_t *me = router_get_my_routerinfo();
  if (! me)
    return NULL;
  tor_assert(me->cache_info.saved_location == SAVED_NOWHERE);
  body = signed_descriptor_get_body(&me->cache_info);
  /* Make sure this is nul-terminated. */
  tor_assert(!body[me->cache_info.signed_descriptor_len]);
  log_debug(LD_GENERAL,"my desc is '%s'", body);
  return body;
}

/** Return the extrainfo document for this OR, or NULL if we have none.
 * Rebuilt it (and the server descriptor) if necessary. */
extrainfo_t *
router_get_my_extrainfo(void)
{
  if (!server_mode(get_options()))
    return NULL;
  if (!router_rebuild_descriptor(0))
    return NULL;
  return desc_extrainfo;
}

/** Return a human-readable string describing what triggered us to generate
 * our current descriptor, or NULL if we don't know. */
const char *
router_get_descriptor_gen_reason(void)
{
  return desc_gen_reason;
}

/* Like router_check_descriptor_address_consistency, but specifically for the
 * ORPort or DirPort.
 * listener_type is either CONN_TYPE_OR_LISTENER or CONN_TYPE_DIR_LISTENER. */
static void
router_check_descriptor_address_port_consistency(const tor_addr_t *addr,
                                                 int listener_type)
{
  int family, port_cfg;

  tor_assert(addr);
  tor_assert(listener_type == CONN_TYPE_OR_LISTENER ||
             listener_type == CONN_TYPE_DIR_LISTENER);

  family = tor_addr_family(addr);
  /* The first advertised Port may be the magic constant CFG_AUTO_PORT. */
  port_cfg = portconf_get_first_advertised_port(listener_type, family);
  if (port_cfg != 0 &&
      !port_exists_by_type_addr_port(listener_type, addr, port_cfg, 1)) {
    const tor_addr_t *port_addr =
      portconf_get_first_advertised_addr(listener_type, family);
    /* If we're building a descriptor with no advertised address,
     * something is terribly wrong. */
    tor_assert(port_addr);

    char port_addr_str[TOR_ADDR_BUF_LEN];
    char desc_addr_str[TOR_ADDR_BUF_LEN];

    tor_addr_to_str(port_addr_str, port_addr, TOR_ADDR_BUF_LEN, 0);
    tor_addr_to_str(desc_addr_str, addr, TOR_ADDR_BUF_LEN, 0);

    const char *listener_str = (listener_type == CONN_TYPE_OR_LISTENER ?
                                "OR" : "Dir");
    const char *af_str = fmt_af_family(family);
    log_warn(LD_CONFIG, "The %s %sPort address %s does not match the "
             "descriptor address %s. If you have a static public IPv4 "
             "address, use 'Address <%s>' and 'OutboundBindAddress "
             "<%s>'. If you are behind a NAT, use two %sPort lines: "
             "'%sPort <PublicPort> NoListen' and '%sPort <InternalPort> "
             "NoAdvertise'.",
             af_str, listener_str, port_addr_str, desc_addr_str, af_str,
             af_str, listener_str, listener_str, listener_str);
  }
}

/** Tor relays only have one IPv4 or/and one IPv6 address in the descriptor,
 * which is derived from the Address torrc option, or guessed using various
 * methods in relay_find_addr_to_publish().
 *
 * Warn the operator if there is no ORPort associated with the given address
 * in addr.
 *
 * Warn the operator if there is no DirPort on the descriptor address.
 *
 * This catches a few common config errors:
 *  - operators who expect ORPorts and DirPorts to be advertised on the
 *    ports' listen addresses, rather than the torrc Address (or guessed
 *    addresses in the absence of an Address config). This includes
 *    operators who attempt to put their ORPort and DirPort on different
 *    addresses;
 *  - discrepancies between guessed addresses and configured listen
 *    addresses (when the Address option isn't set).
 *
 * If a listener is listening on all IPv4 addresses, it is assumed that it
 * is listening on the configured Address, and no messages are logged.
 *
 * If an operators has specified NoAdvertise ORPorts in a NAT setting,
 * no messages are logged, unless they have specified other advertised
 * addresses.
 *
 * The message tells operators to configure an ORPort and DirPort that match
 * the Address (using NoListen if needed). */
static void
router_check_descriptor_address_consistency(const tor_addr_t *addr)
{
  router_check_descriptor_address_port_consistency(addr,
                                                   CONN_TYPE_OR_LISTENER);
  router_check_descriptor_address_port_consistency(addr,
                                                   CONN_TYPE_DIR_LISTENER);
}

/** A list of nicknames that we've warned about including in our family,
 * for one reason or another. */
static smartlist_t *warned_family = NULL;

/**
 * Return a new smartlist containing the family members configured in
 * <b>options</b>.  Warn about invalid or missing entries.  Return NULL
 * if this relay should not declare a family.
 **/
STATIC smartlist_t *
get_my_declared_family(const or_options_t *options)
{
  if (!options->MyFamily)
    return NULL;

  if (options->BridgeRelay)
    return NULL;

  if (!warned_family)
    warned_family = smartlist_new();

  smartlist_t *declared_family = smartlist_new();
  config_line_t *family;

  /* First we try to get the whole family in the form of hexdigests. */
  for (family = options->MyFamily; family; family = family->next) {
    char *name = family->value;
    const node_t *member;
    if (options->Nickname && !strcasecmp(name, options->Nickname))
      continue; /* Don't list ourself by nickname, that's redundant */
    else
      member = node_get_by_nickname(name, 0);

    if (!member) {
      /* This node doesn't seem to exist, so warn about it if it is not
       * a hexdigest. */
      int is_legal = is_legal_nickname_or_hexdigest(name);
      if (!smartlist_contains_string(warned_family, name) &&
          !is_legal_hexdigest(name)) {
        if (is_legal)
          log_warn(LD_CONFIG,
                   "There is a router named %s in my declared family, but "
                   "I have no descriptor for it. I'll use the nickname "
                   "as is, but this may confuse clients. Please list it "
                   "by identity digest instead.", escaped(name));
        else
          log_warn(LD_CONFIG, "There is a router named %s in my declared "
                   "family, but that isn't a legal digest or nickname. "
                   "Skipping it.", escaped(name));
        smartlist_add_strdup(warned_family, name);
      }
      if (is_legal) {
        smartlist_add_strdup(declared_family, name);
      }
    } else {
      /* List the node by digest. */
      char *fp = tor_malloc(HEX_DIGEST_LEN+2);
      fp[0] = '$';
      base16_encode(fp+1,HEX_DIGEST_LEN+1,
                    member->identity, DIGEST_LEN);
      smartlist_add(declared_family, fp);

      if (! is_legal_hexdigest(name) &&
          !smartlist_contains_string(warned_family, name)) {
        /* Warn if this node was not specified by hexdigest. */
        log_warn(LD_CONFIG, "There is a router named %s in my declared "
                 "family, but it wasn't listed by digest. Please consider "
                 "saying %s instead, if that's what you meant.",
                 escaped(name), fp);
        smartlist_add_strdup(warned_family, name);
      }
    }
  }

  /* Now declared_family should have the closest we can come to the
   * identities that the user wanted.
   *
   * Unlike older versions of Tor, we _do_ include our own identity: this
   * helps microdescriptor compression, and helps in-memory compression
   * on clients. */
  nodefamily_t *nf = nodefamily_from_members(declared_family,
                                     router_get_my_id_digest(),
                                     NF_WARN_MALFORMED,
                                     NULL);
  SMARTLIST_FOREACH(declared_family, char *, s, tor_free(s));
  smartlist_free(declared_family);
  if (!nf) {
    return NULL;
  }

  char *s = nodefamily_format(nf);
  nodefamily_free(nf);

  smartlist_t *result = smartlist_new();
  smartlist_split_string(result, s, NULL,
                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
  tor_free(s);

  if (smartlist_len(result) == 1) {
    /* This is a one-element list containing only ourself; instead return
     * nothing */
    const char *singleton = smartlist_get(result, 0);
    bool is_me = false;
    if (singleton[0] == '$') {
      char d[DIGEST_LEN];
      int n = base16_decode(d, sizeof(d), singleton+1, strlen(singleton+1));
      if (n == DIGEST_LEN &&
          fast_memeq(d, router_get_my_id_digest(), DIGEST_LEN)) {
        is_me = true;
      }
    }
    if (!is_me) {
      // LCOV_EXCL_START
      log_warn(LD_BUG, "Found a singleton family list with an element "
               "that wasn't us! Element was %s", escaped(singleton));
      // LCOV_EXCL_STOP
    } else {
      SMARTLIST_FOREACH(result, char *, cp, tor_free(cp));
      smartlist_free(result);
      return NULL;
    }
  }

  return result;
}

/** Allocate a fresh, unsigned routerinfo for this OR, without any of the
 * fields that depend on the corresponding extrainfo.
 *
 * On success, set ri_out to the new routerinfo, and return 0.
 * Caller is responsible for freeing the generated routerinfo.
 *
 * Returns a negative value and sets ri_out to NULL on temporary error.
 */
MOCK_IMPL(STATIC int,
router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
{
  routerinfo_t *ri = NULL;
  tor_addr_t ipv4_addr;
  char platform[256];
  int hibernating = we_are_hibernating();
  const or_options_t *options = get_options();
  int result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;

  if (BUG(!ri_out)) {
    result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
    goto err;
  }

  /* Find our resolved address both IPv4 and IPv6. In case the address is not
   * found, the object is set to an UNSPEC address. */
  bool have_v4 = relay_find_addr_to_publish(options, AF_INET,
                                            RELAY_FIND_ADDR_NO_FLAG,
                                            &ipv4_addr);
  /* Tor requires a relay to have an IPv4 so bail if we can't find it. */
  if (!have_v4) {
    log_info(LD_CONFIG, "Don't know my address while generating descriptor. "
                        "Launching circuit to authority to learn it.");
    relay_addr_learn_from_dirauth();
    result = TOR_ROUTERINFO_ERROR_NO_EXT_ADDR;
    goto err;
  }
  /* Log a message if the address in the descriptor doesn't match the ORPort
   * and DirPort addresses configured by the operator. */
  router_check_descriptor_address_consistency(&ipv4_addr);

  ri = tor_malloc_zero(sizeof(routerinfo_t));
  tor_addr_copy(&ri->ipv4_addr, &ipv4_addr);
  ri->cache_info.routerlist_index = -1;
  ri->nickname = tor_strdup(options->Nickname);

  /* IPv4. */
  ri->ipv4_orport = routerconf_find_or_port(options, AF_INET);
  ri->ipv4_dirport = routerconf_find_dir_port(options, 0);

  /* Optionally check for an IPv6. We still publish without one. */
  if (relay_find_addr_to_publish(options, AF_INET6, RELAY_FIND_ADDR_NO_FLAG,
                                 &ri->ipv6_addr)) {
    ri->ipv6_orport = routerconf_find_or_port(options, AF_INET6);
    router_check_descriptor_address_consistency(&ri->ipv6_addr);
  }

  ri->supports_tunnelled_dir_requests =
    directory_permits_begindir_requests(options);
  ri->cache_info.published_on = time(NULL);
  /* get_onion_key() must invoke from main thread */
  router_set_rsa_onion_pkey(get_onion_key(), &ri->onion_pkey,
                            &ri->onion_pkey_len);

  ri->onion_curve25519_pkey =
    tor_memdup(&get_current_curve25519_keypair()->pubkey,
               sizeof(curve25519_public_key_t));

  ri->identity_pkey = crypto_pk_dup_key(get_server_identity_key());
  if (BUG(crypto_pk_get_digest(ri->identity_pkey,
                           ri->cache_info.identity_digest) < 0)) {
    result = TOR_ROUTERINFO_ERROR_DIGEST_FAILED;
    goto err;
  }
  ri->cache_info.signing_key_cert =
    tor_cert_dup(get_master_signing_key_cert());

  get_platform_str(platform, sizeof(platform));
  ri->platform = tor_strdup(platform);

  ri->protocol_list = tor_strdup(protover_get_supported_protocols());

  /* compute ri->bandwidthrate as the min of various options */
  ri->bandwidthrate = relay_get_effective_bwrate(options);

  /* and compute ri->bandwidthburst similarly */
  ri->bandwidthburst = relay_get_effective_bwburst(options);

  /* Report bandwidth, unless we're hibernating or shutting down */
  ri->bandwidthcapacity = hibernating ? 0 : bwhist_bandwidth_assess();

  if (dns_seems_to_be_broken() || has_dns_init_failed()) {
    /* DNS is screwed up; don't claim to be an exit. */
    policies_exit_policy_append_reject_star(&ri->exit_policy);
  } else {
    policies_parse_exit_policy_from_options(options, &ri->ipv4_addr,
                                            &ri->ipv6_addr,
                                            &ri->exit_policy);
  }
  ri->policy_is_reject_star =
    policy_is_reject_star(ri->exit_policy, AF_INET, 1) &&
    policy_is_reject_star(ri->exit_policy, AF_INET6, 1);

  if (options->IPv6Exit) {
    char *p_tmp = policy_summarize(ri->exit_policy, AF_INET6);
    if (p_tmp)
      ri->ipv6_exit_policy = parse_short_policy(p_tmp);
    tor_free(p_tmp);
  }

  ri->declared_family = get_my_declared_family(options);

  if (options->BridgeRelay) {
    ri->purpose = ROUTER_PURPOSE_BRIDGE;
    /* Bridges shouldn't be able to send their descriptors unencrypted,
     anyway, since they don't have a DirPort, and always connect to the
     bridge authority anonymously.  But just in case they somehow think of
     sending them on an unencrypted connection, don't allow them to try. */
    ri->cache_info.send_unencrypted = 0;
  } else {
    ri->purpose = ROUTER_PURPOSE_GENERAL;
    ri->cache_info.send_unencrypted = 1;
  }

  goto done;

 err:
  routerinfo_free(ri);
  *ri_out = NULL;
  return result;

 done:
  *ri_out = ri;
  return 0;
}

/** Allocate and return a fresh, unsigned extrainfo for this OR, based on the
 * routerinfo ri.
 *
 * Uses options->Nickname to set the nickname, and options->BridgeRelay to set
 * ei->cache_info.send_unencrypted.
 *
 * If ri is NULL, logs a BUG() warning and returns NULL.
 * Caller is responsible for freeing the generated extrainfo.
 */
static extrainfo_t *
router_build_fresh_unsigned_extrainfo(const routerinfo_t *ri)
{
  extrainfo_t *ei = NULL;
  const or_options_t *options = get_options();

  if (BUG(!ri))
    return NULL;

  /* Now generate the extrainfo. */
  ei = tor_malloc_zero(sizeof(extrainfo_t));
  ei->cache_info.is_extrainfo = 1;
  strlcpy(ei->nickname, options->Nickname, sizeof(ei->nickname));
  ei->cache_info.published_on = ri->cache_info.published_on;
  ei->cache_info.signing_key_cert =
    tor_cert_dup(get_master_signing_key_cert());

  memcpy(ei->cache_info.identity_digest, ri->cache_info.identity_digest,
         DIGEST_LEN);

  if (options->BridgeRelay) {
    /* See note in router_build_fresh_routerinfo(). */
    ei->cache_info.send_unencrypted = 0;
  } else {
    ei->cache_info.send_unencrypted = 1;
  }

  return ei;
}

/** Dump the extrainfo descriptor body for ei, sign it, and add the body and
 * signature to ei->cache_info. Note that the extrainfo body is determined by
 * ei, and some additional config and statistics state: see
 * extrainfo_dump_to_string() for details.
 *
 * Return 0 on success, -1 on temporary error.
 * If ei is NULL, logs a BUG() warning and returns -1.
 * On error, ei->cache_info is not modified.
 */
static int
router_dump_and_sign_extrainfo_descriptor_body(extrainfo_t *ei)
{
  if (BUG(!ei))
    return -1;

  if (extrainfo_dump_to_string(&ei->cache_info.signed_descriptor_body,
                               ei, get_server_identity_key(),
                               get_master_signing_keypair()) < 0) {
    log_warn(LD_BUG, "Couldn't generate extra-info descriptor.");
    return -1;
  }

  ei->cache_info.signed_descriptor_len =
    strlen(ei->cache_info.signed_descriptor_body);

  router_get_extrainfo_hash(ei->cache_info.signed_descriptor_body,
                            ei->cache_info.signed_descriptor_len,
                            ei->cache_info.signed_descriptor_digest);
  crypto_digest256((char*) ei->digest256,
                   ei->cache_info.signed_descriptor_body,
                   ei->cache_info.signed_descriptor_len,
                   DIGEST_SHA256);

  return 0;
}

/** Allocate and return a fresh, signed extrainfo for this OR, based on the
 * routerinfo ri.
 *
 * If ri is NULL, logs a BUG() warning and returns NULL.
 * Caller is responsible for freeing the generated extrainfo.
 */
STATIC extrainfo_t *
router_build_fresh_signed_extrainfo(const routerinfo_t *ri)
{
  int result = -1;
  extrainfo_t *ei = NULL;

  if (BUG(!ri))
    return NULL;

  ei = router_build_fresh_unsigned_extrainfo(ri);
  /* router_build_fresh_unsigned_extrainfo() should not fail. */
  if (BUG(!ei))
    goto err;

  result = router_dump_and_sign_extrainfo_descriptor_body(ei);
  if (result < 0)
    goto err;

  goto done;

 err:
  extrainfo_free(ei);
  return NULL;

 done:
  return ei;
}

/** Set the fields in ri that depend on ei.
 *
 * If ei is NULL, logs a BUG() warning and zeroes the relevant fields.
 */
STATIC void
router_update_routerinfo_from_extrainfo(routerinfo_t *ri,
                                        const extrainfo_t *ei)
{
  if (BUG(!ei)) {
    /* Just to be safe, zero ri->cache_info.extra_info_digest here. */
    memset(ri->cache_info.extra_info_digest, 0, DIGEST_LEN);
    memset(ri->cache_info.extra_info_digest256, 0, DIGEST256_LEN);
    return;
  }

  /* Now finish the router descriptor. */
  memcpy(ri->cache_info.extra_info_digest,
         ei->cache_info.signed_descriptor_digest,
         DIGEST_LEN);
  memcpy(ri->cache_info.extra_info_digest256,
         ei->digest256,
         DIGEST256_LEN);
}

/** Dump the descriptor body for ri, sign it, and add the body and signature to
 * ri->cache_info. Note that the descriptor body is determined by ri, and some
 * additional config and state: see router_dump_router_to_string() for details.
 *
 * Return 0 on success, and a negative value on temporary error.
 * If ri is NULL, logs a BUG() warning and returns a negative value.
 * On error, ri->cache_info is not modified.
 */
STATIC int
router_dump_and_sign_routerinfo_descriptor_body(routerinfo_t *ri)
{
  if (BUG(!ri))
    return TOR_ROUTERINFO_ERROR_INTERNAL_BUG;

  if (! (ri->cache_info.signed_descriptor_body =
          router_dump_router_to_string(ri, get_server_identity_key(),
                                       get_onion_key(),
                                       get_current_curve25519_keypair(),
                                       get_master_signing_keypair())) ) {
    log_warn(LD_BUG, "Couldn't generate router descriptor.");
    return TOR_ROUTERINFO_ERROR_CANNOT_GENERATE;
  }

  ri->cache_info.signed_descriptor_len =
    strlen(ri->cache_info.signed_descriptor_body);

  router_get_router_hash(ri->cache_info.signed_descriptor_body,
                         strlen(ri->cache_info.signed_descriptor_body),
                         ri->cache_info.signed_descriptor_digest);

  return 0;
}

/** Build a fresh routerinfo, signed server descriptor, and signed extrainfo
 * document for this OR.
 *
 * Set r to the generated routerinfo, e to the generated extrainfo document.
 * Failure to generate an extra-info document is not an error and is indicated
 * by setting e to NULL.
 * Return 0 on success, and a negative value on temporary error.
 * Caller is responsible for freeing generated documents on success.
 */
int
router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e)
{
  int result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
  routerinfo_t *ri = NULL;
  extrainfo_t *ei = NULL;

  if (BUG(!r))
    goto err;

  if (BUG(!e))
    goto err;

  result = router_build_fresh_unsigned_routerinfo(&ri);
  if (result < 0) {
    goto err;
  }
  /* If ri is NULL, then result should be negative. So this check should be
   * unreachable. */
  if (BUG(!ri)) {
    result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
    goto err;
  }

  ei = router_build_fresh_signed_extrainfo(ri);

  /* Failing to create an ei is not an error. */
  if (ei) {
    router_update_routerinfo_from_extrainfo(ri, ei);
  }

  result = router_dump_and_sign_routerinfo_descriptor_body(ri);
  if (result < 0)
    goto err;

  if (ei) {
     if (BUG(routerinfo_incompatible_with_extrainfo(ri->identity_pkey, ei,
                                                    &ri->cache_info, NULL))) {
       result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
       goto err;
     }
  }

  goto done;

 err:
  routerinfo_free(ri);
  extrainfo_free(ei);
  *r = NULL;
  *e = NULL;
  return result;

 done:
  *r = ri;
  *e = ei;
  return 0;
}

/** If <b>force</b> is true, or our descriptor is out-of-date, rebuild a fresh
 * routerinfo, signed server descriptor, and extra-info document for this OR.
 *
 * Return true on success, else false on temporary error.
 */
bool
router_rebuild_descriptor(int force)
{
  int err = 0;
  routerinfo_t *ri;
  extrainfo_t *ei;

  if (desc_clean_since && !force)
    return true;

  log_info(LD_OR, "Rebuilding relay descriptor%s", force ? " (forced)" : "");

  err = router_build_fresh_descriptor(&ri, &ei);
  if (err < 0) {
    return false;
  }

  routerinfo_free(desc_routerinfo);
  desc_routerinfo = ri;
  extrainfo_free(desc_extrainfo);
  desc_extrainfo = ei;

  desc_clean_since = time(NULL);
  desc_needs_upload = 1;
  desc_gen_reason = desc_dirty_reason;
  if (BUG(desc_gen_reason == NULL)) {
    desc_gen_reason = "descriptor was marked dirty earlier, for no reason.";
  }
  desc_dirty_reason = NULL;
  control_event_my_descriptor_changed();
  return true;
}

/** Called when we have a new set of consensus parameters. */
void
router_new_consensus_params(const networkstatus_t *ns)
{
  const int32_t DEFAULT_ASSUME_REACHABLE = 0;
  const int32_t DEFAULT_ASSUME_REACHABLE_IPV6 = 0;
  int ar, ar6;
  ar = networkstatus_get_param(ns,
                               "assume-reachable",
                               DEFAULT_ASSUME_REACHABLE, 0, 1);
  ar6 = networkstatus_get_param(ns,
                                "assume-reachable-ipv6",
                                DEFAULT_ASSUME_REACHABLE_IPV6, 0, 1);

  publish_even_when_ipv4_orport_unreachable = ar;
  publish_even_when_ipv6_orport_unreachable = ar || ar6;
}

/** Mark our descriptor out of data iff the IPv6 omit status flag is flipped
 * it changes from its previous value.
 *
 * This is used when our IPv6 port is found reachable or not. */
void
mark_my_descriptor_if_omit_ipv6_changes(const char *reason, bool omit_ipv6)
{
  bool previous = omit_ipv6_on_publish;
  omit_ipv6_on_publish = omit_ipv6;

  /* Only mark it dirty if the IPv6 omit flag was flipped. */
  if (previous != omit_ipv6) {
    mark_my_descriptor_dirty(reason);
  }
}

/** If our router descriptor ever goes this long without being regenerated
 * because something changed, we force an immediate regenerate-and-upload. */
#define FORCE_REGENERATE_DESCRIPTOR_INTERVAL (18*60*60)

/** If our router descriptor seems to be missing or unacceptable according
 * to the authorities, regenerate and reupload it _this_ often. */
#define FAST_RETRY_DESCRIPTOR_INTERVAL (90*60)

/** Mark descriptor out of date if it's been "too long" since we last tried
 * to upload one. */
void
mark_my_descriptor_dirty_if_too_old(time_t now)
{
  networkstatus_t *ns;
  const routerstatus_t *rs;
  const char *retry_fast_reason = NULL; /* Set if we should retry frequently */
  const time_t slow_cutoff = now - FORCE_REGENERATE_DESCRIPTOR_INTERVAL;
  const time_t fast_cutoff = now - FAST_RETRY_DESCRIPTOR_INTERVAL;

  /* If it's already dirty, don't mark it. */
  if (! desc_clean_since)
    return;

  /* If it's older than FORCE_REGENERATE_DESCRIPTOR_INTERVAL, it's always
   * time to rebuild it. */
  if (desc_clean_since < slow_cutoff) {
    mark_my_descriptor_dirty("time for new descriptor");
    return;
  }
  /* Now we see whether we want to be retrying frequently or no.  The
   * rule here is that we'll retry frequently if we aren't listed in the
   * live consensus we have, or if the publication time of the
   * descriptor listed for us in the consensus is very old, or if the
   * consensus lists us as "stale" and we haven't regenerated since the
   * consensus was published. */
  ns = networkstatus_get_live_consensus(now);
  if (ns) {
    rs = networkstatus_vote_find_entry(ns, server_identitykey_digest);
    if (rs == NULL)
      retry_fast_reason = "not listed in consensus";
    else if (rs->published_on < slow_cutoff)
      retry_fast_reason = "version listed in consensus is quite old";
    else if (rs->is_staledesc && ns->valid_after > desc_clean_since)
      retry_fast_reason = "listed as stale in consensus";
  }

  if (retry_fast_reason && desc_clean_since < fast_cutoff)
    mark_my_descriptor_dirty(retry_fast_reason);
}

/** Call when the current descriptor is out of date. */
void
mark_my_descriptor_dirty(const char *reason)
{
  const or_options_t *options = get_options();
  if (BUG(reason == NULL)) {
    reason = "marked descriptor dirty for unspecified reason";
  }
  if (server_mode(options) && options->PublishServerDescriptor_) {
    log_info(LD_OR, "Decided to publish new relay descriptor: %s", reason);
  }
  desc_clean_since = 0;
  if (!desc_dirty_reason)
    desc_dirty_reason = reason;
  reschedule_descriptor_update_check();
}

/** How frequently will we republish our descriptor because of large (factor
 * of 2) shifts in estimated bandwidth? Note: We don't use this constant
 * if our previous bandwidth estimate was exactly 0. */
#define MAX_BANDWIDTH_CHANGE_FREQ (3*60*60)

/** Maximum uptime to republish our descriptor because of large shifts in
 * estimated bandwidth. */
#define MAX_UPTIME_BANDWIDTH_CHANGE (24*60*60)

/** By which factor bandwidth shifts have to change to be considered large. */
#define BANDWIDTH_CHANGE_FACTOR 2

/** Check whether bandwidth has changed a lot since the last time we announced
 * bandwidth while the uptime is smaller than MAX_UPTIME_BANDWIDTH_CHANGE.
 * If so, mark our descriptor dirty. */
void
check_descriptor_bandwidth_changed(time_t now)
{
  static time_t last_changed = 0;
  uint64_t prev, cur;
  const int hibernating = we_are_hibernating();

  /* If the relay uptime is bigger than MAX_UPTIME_BANDWIDTH_CHANGE,
   * the next regularly scheduled descriptor update (18h) will be enough */
  if (get_uptime() > MAX_UPTIME_BANDWIDTH_CHANGE && !hibernating)
    return;

  const routerinfo_t *my_ri = router_get_my_routerinfo();

  if (!my_ri)
    return;

  prev = my_ri->bandwidthcapacity;

  /* Consider ourselves to have zero bandwidth if we're hibernating or
   * shutting down. */
  cur = hibernating ? 0 : bwhist_bandwidth_assess();

  if ((prev != cur && (!prev || !cur)) ||
      cur > (prev * BANDWIDTH_CHANGE_FACTOR) ||
      cur < (prev / BANDWIDTH_CHANGE_FACTOR) ) {
    const bool change_recent_enough =
      last_changed+MAX_BANDWIDTH_CHANGE_FREQ < now;
    const bool testing_network = get_options()->TestingTorNetwork;
    if (change_recent_enough || testing_network || !prev) {
      log_info(LD_GENERAL,
               "Measured bandwidth has changed; rebuilding descriptor.");
      mark_my_descriptor_dirty("bandwidth has changed");
      last_changed = now;
    }
  }
}

// This function can be "noreturn" if relay mode is disabled and
// ALL_BUGS_ARE_FATAL is set.
DISABLE_GCC_WARNING("-Wmissing-noreturn")

/** Note at log level severity that our best guess of address has changed from
 * <b>prev</b> to <b>cur</b>. */
void
log_addr_has_changed(int severity,
                     const tor_addr_t *prev,
                     const tor_addr_t *cur,
                     const char *source)
{
  char addrbuf_prev[TOR_ADDR_BUF_LEN];
  char addrbuf_cur[TOR_ADDR_BUF_LEN];

  if (BUG(!server_mode(get_options())))
    return;

  if (tor_addr_to_str(addrbuf_prev, prev, sizeof(addrbuf_prev), 1) == NULL)
    strlcpy(addrbuf_prev, "???", TOR_ADDR_BUF_LEN);
  if (tor_addr_to_str(addrbuf_cur, cur, sizeof(addrbuf_cur), 1) == NULL)
    strlcpy(addrbuf_cur, "???", TOR_ADDR_BUF_LEN);

  if (!tor_addr_is_null(prev))
    log_fn(severity, LD_GENERAL,
           "Our IP Address has changed from %s to %s; "
           "rebuilding descriptor (source: %s).",
           addrbuf_prev, addrbuf_cur, source);
  else
    log_notice(LD_GENERAL,
             "Guessed our IP address as %s (source: %s).",
             addrbuf_cur, source);
}
ENABLE_GCC_WARNING("-Wmissing-noreturn")

/** Check whether our own address has changed versus the one we have in our
 * current descriptor.
 *
 * If our address has changed, call ip_address_changed() which takes
 * appropriate actions. */
void
check_descriptor_ipaddress_changed(time_t now)
{
  const routerinfo_t *my_ri = router_get_my_routerinfo();
  resolved_addr_method_t method = RESOLVED_ADDR_NONE;
  char *hostname = NULL;
  int families[2] = { AF_INET, AF_INET6 };
  bool has_changed = false;

  (void) now;

  /* We can't learn our descriptor address without one. */
  if (my_ri == NULL) {
    return;
  }

  for (size_t i = 0; i < ARRAY_LENGTH(families); i++) {
    tor_addr_t current;
    const tor_addr_t *previous;
    int family = families[i];

    /* Get the descriptor address from the family we are looking up. */
    previous = &my_ri->ipv4_addr;
    if (family == AF_INET6) {
      previous = &my_ri->ipv6_addr;
    }

    /* Attempt to discovery the publishable address for the family which will
     * actively attempt to discover the address if we are configured with a
     * port for the family.
     *
     * It is OK to ignore the returned value here since in the failure case,
     * that is the address was not found, the current value is set to UNSPEC.
     * Add this (void) so Coverity is happy. */
    (void) relay_find_addr_to_publish(get_options(), family,
                                      RELAY_FIND_ADDR_NO_FLAG, &current);

    /* The "current" address might be UNSPEC meaning it was not discovered nor
     * found in our current cache. If we had an address before and we have
     * none now, we consider this an IP change since it appears the relay lost
     * its address. */

    if (!tor_addr_eq(previous, &current)) {
      char *source;
      tor_asprintf(&source, "METHOD=%s%s%s",
                   resolved_addr_method_to_str(method),
                   hostname ? " HOSTNAME=" : "",
                   hostname ? hostname : "");
      log_addr_has_changed(LOG_NOTICE, previous, &current, source);
      tor_free(source);
      has_changed = true;
    }
    tor_free(hostname);
  }

  if (has_changed) {
    ip_address_changed(0);
  }
}

/** Set <b>platform</b> (max length <b>len</b>) to a NUL-terminated short
 * string describing the version of Tor and the operating system we're
 * currently running on.
 */
STATIC void
get_platform_str(char *platform, size_t len)
{
  tor_snprintf(platform, len, "Tor %s on %s",
               get_short_version(), get_uname());
}

/* XXX need to audit this thing and count fenceposts. maybe
 *     refactor so we don't have to keep asking if we're
 *     near the end of maxlen?
 */
#define DEBUG_ROUTER_DUMP_ROUTER_TO_STRING

/** OR only: Given a routerinfo for this router, and an identity key to sign
 * with, encode the routerinfo as a signed server descriptor and return a new
 * string encoding the result, or NULL on failure.
 *
 * In addition to the fields in router, this function calls
 * onion_key_lifetime(), get_options(), and we_are_hibernating(), and uses the
 * results to populate some fields in the descriptor.
 */
char *
router_dump_router_to_string(routerinfo_t *router,
                             const crypto_pk_t *ident_key,
                             const crypto_pk_t *tap_key,
                             const curve25519_keypair_t *ntor_keypair,
                             const ed25519_keypair_t *signing_keypair)
{
  char *address = NULL;
  char *onion_pkey = NULL; /* Onion key, PEM-encoded. */
  crypto_pk_t *rsa_pubkey = NULL;
  char *identity_pkey = NULL; /* Identity key, PEM-encoded. */
  char digest[DIGEST256_LEN];
  char published[ISO_TIME_LEN+1];
  char fingerprint[FINGERPRINT_LEN+1];
  char *extra_info_line = NULL;
  size_t onion_pkeylen, identity_pkeylen;
  char *family_line = NULL;
  char *extra_or_address = NULL;
  const or_options_t *options = get_options();
  smartlist_t *chunks = NULL;
  char *output = NULL;
  const int emit_ed_sigs = signing_keypair &&
    router->cache_info.signing_key_cert;
  char *ed_cert_line = NULL;
  char *rsa_tap_cc_line = NULL;
  char *ntor_cc_line = NULL;
  char *proto_line = NULL;

  /* Make sure the identity key matches the one in the routerinfo. */
  if (!crypto_pk_eq_keys(ident_key, router->identity_pkey)) {
    log_warn(LD_BUG,"Tried to sign a router with a private key that didn't "
             "match router's public key!");
    goto err;
  }
  if (emit_ed_sigs) {
    if (!router->cache_info.signing_key_cert->signing_key_included ||
        !ed25519_pubkey_eq(&router->cache_info.signing_key_cert->signed_key,
                           &signing_keypair->pubkey)) {
      log_warn(LD_BUG, "Tried to sign a router descriptor with a mismatched "
               "ed25519 key chain %d",
               router->cache_info.signing_key_cert->signing_key_included);
      goto err;
    }
  }

  /* record our fingerprint, so we can include it in the descriptor */
  if (crypto_pk_get_fingerprint(router->identity_pkey, fingerprint, 1)<0) {
    log_err(LD_BUG,"Error computing fingerprint");
    goto err;
  }

  if (emit_ed_sigs) {
    /* Encode ed25519 signing cert */
    char ed_cert_base64[256];
    char ed_fp_base64[ED25519_BASE64_LEN+1];
    if (base64_encode(ed_cert_base64, sizeof(ed_cert_base64),
                    (const char*)router->cache_info.signing_key_cert->encoded,
                    router->cache_info.signing_key_cert->encoded_len,
                    BASE64_ENCODE_MULTILINE) < 0) {
      log_err(LD_BUG,"Couldn't base64-encode signing key certificate!");
      goto err;
    }
    ed25519_public_to_base64(ed_fp_base64,
                            &router->cache_info.signing_key_cert->signing_key);
    tor_asprintf(&ed_cert_line, "identity-ed25519\n"
                 "-----BEGIN ED25519 CERT-----\n"
                 "%s"
                 "-----END ED25519 CERT-----\n"
                 "master-key-ed25519 %s\n",
                 ed_cert_base64, ed_fp_base64);
  }

  /* PEM-encode the onion key */
  rsa_pubkey = router_get_rsa_onion_pkey(router->onion_pkey,
                                         router->onion_pkey_len);
  if (crypto_pk_write_public_key_to_string(rsa_pubkey,
                                           &onion_pkey,&onion_pkeylen)<0) {
    log_warn(LD_BUG,"write onion_pkey to string failed!");
    goto err;
  }

  /* PEM-encode the identity key */
  if (crypto_pk_write_public_key_to_string(router->identity_pkey,
                                        &identity_pkey,&identity_pkeylen)<0) {
    log_warn(LD_BUG,"write identity_pkey to string failed!");
    goto err;
  }

  /* Cross-certify with RSA key */
  if (tap_key && router->cache_info.signing_key_cert &&
      router->cache_info.signing_key_cert->signing_key_included) {
    char buf[256];
    int tap_cc_len = 0;
    uint8_t *tap_cc =
      make_tap_onion_key_crosscert(tap_key,
                            &router->cache_info.signing_key_cert->signing_key,
                            router->identity_pkey,
                            &tap_cc_len);
    if (!tap_cc) {
      log_warn(LD_BUG,"make_tap_onion_key_crosscert failed!");
      goto err;
    }

    if (base64_encode(buf, sizeof(buf), (const char*)tap_cc, tap_cc_len,
                      BASE64_ENCODE_MULTILINE) < 0) {
      log_warn(LD_BUG,"base64_encode(rsa_crosscert) failed!");
      tor_free(tap_cc);
      goto err;
    }
    tor_free(tap_cc);

    tor_asprintf(&rsa_tap_cc_line,
                 "onion-key-crosscert\n"
                 "-----BEGIN CROSSCERT-----\n"
                 "%s"
                 "-----END CROSSCERT-----\n", buf);
  }

  /* Cross-certify with onion keys */
  if (ntor_keypair && router->cache_info.signing_key_cert &&
      router->cache_info.signing_key_cert->signing_key_included) {
    int sign = 0;
    char buf[256];
    /* XXXX Base the expiration date on the actual onion key expiration time?*/
    tor_cert_t *cert =
      make_ntor_onion_key_crosscert(ntor_keypair,
                         &router->cache_info.signing_key_cert->signing_key,
                         router->cache_info.published_on,
                         get_onion_key_lifetime(), &sign);
    if (!cert) {
      log_warn(LD_BUG,"make_ntor_onion_key_crosscert failed!");
      goto err;
    }
    tor_assert(sign == 0 || sign == 1);

    if (base64_encode(buf, sizeof(buf),
                      (const char*)cert->encoded, cert->encoded_len,
                      BASE64_ENCODE_MULTILINE)<0) {
      log_warn(LD_BUG,"base64_encode(ntor_crosscert) failed!");
      tor_cert_free(cert);
      goto err;
    }
    tor_cert_free(cert);

    tor_asprintf(&ntor_cc_line,
                 "ntor-onion-key-crosscert %d\n"
                 "-----BEGIN ED25519 CERT-----\n"
                 "%s"
                 "-----END ED25519 CERT-----\n", sign, buf);
  }

  /* Encode the publication time. */
  format_iso_time(published, router->cache_info.published_on);

  if (router->declared_family && smartlist_len(router->declared_family)) {
    char *family = smartlist_join_strings(router->declared_family,
                                          " ", 0, NULL);
    tor_asprintf(&family_line, "family %s\n", family);
    tor_free(family);
  } else {
    family_line = tor_strdup("");
  }

  if (!tor_digest_is_zero(router->cache_info.extra_info_digest)) {
    char extra_info_digest[HEX_DIGEST_LEN+1];
    base16_encode(extra_info_digest, sizeof(extra_info_digest),
                  router->cache_info.extra_info_digest, DIGEST_LEN);
    if (!tor_digest256_is_zero(router->cache_info.extra_info_digest256)) {
      char d256_64[BASE64_DIGEST256_LEN+1];
      digest256_to_base64(d256_64, router->cache_info.extra_info_digest256);
      tor_asprintf(&extra_info_line, "extra-info-digest %s %s\n",
                   extra_info_digest, d256_64);
    } else {
      tor_asprintf(&extra_info_line, "extra-info-digest %s\n",
                   extra_info_digest);
    }
  }

  if (!omit_ipv6_on_publish && router->ipv6_orport &&
      tor_addr_family(&router->ipv6_addr) == AF_INET6) {
    char addr[TOR_ADDR_BUF_LEN];
    const char *a;
    a = tor_addr_to_str(addr, &router->ipv6_addr, sizeof(addr), 1);
    if (a) {
      tor_asprintf(&extra_or_address,
                   "or-address %s:%d\n", a, router->ipv6_orport);
      log_debug(LD_OR, "My or-address line is <%s>", extra_or_address);
    }
  }

  if (router->protocol_list) {
    tor_asprintf(&proto_line, "proto %s\n", router->protocol_list);
  } else {
    proto_line = tor_strdup("");
  }

  address = tor_addr_to_str_dup(&router->ipv4_addr);
  if (!address)
    goto err;

  chunks = smartlist_new();

  /* Generate the easy portion of the router descriptor. */
  smartlist_add_asprintf(chunks,
                    "router %s %s %d 0 %d\n"
                    "%s"
                    "%s"
                    "platform %s\n"
                    "%s"
                    "published %s\n"
                    "fingerprint %s\n"
                    "uptime %ld\n"
                    "bandwidth %d %d %d\n"
                    "%s%s"
                    "onion-key\n%s"
                    "signing-key\n%s"
                    "%s%s"
                    "%s%s%s",
    router->nickname,
    address,
    router->ipv4_orport,
    router_should_advertise_dirport(options, router->ipv4_dirport),
    ed_cert_line ? ed_cert_line : "",
    extra_or_address ? extra_or_address : "",
    router->platform,
    proto_line,
    published,
    fingerprint,
    get_uptime(),
    (int) router->bandwidthrate,
    (int) router->bandwidthburst,
    (int) router->bandwidthcapacity,
    extra_info_line ? extra_info_line : "",
    (options->DownloadExtraInfo || options->V3AuthoritativeDir) ?
                         "caches-extra-info\n" : "",
    onion_pkey, identity_pkey,
    rsa_tap_cc_line ? rsa_tap_cc_line : "",
    ntor_cc_line ? ntor_cc_line : "",
    family_line,
    we_are_hibernating() ? "hibernating 1\n" : "",
    "hidden-service-dir\n");

  if (options->ContactInfo && strlen(options->ContactInfo)) {
    const char *ci = options->ContactInfo;
    if (strchr(ci, '\n') || strchr(ci, '\r'))
      ci = escaped(ci);
    smartlist_add_asprintf(chunks, "contact %s\n", ci);
  }

  if (options->BridgeRelay) {
    char *bd = NULL;

    if (options->BridgeDistribution && strlen(options->BridgeDistribution)) {
      bd = tor_strdup(options->BridgeDistribution);
    } else {
      bd = tor_strdup("any");
    }

    // Make sure our value is lowercased in the descriptor instead of just
    // forwarding what the user wrote in their torrc directly.
    tor_strlower(bd);

    smartlist_add_asprintf(chunks, "bridge-distribution-request %s\n", bd);
    tor_free(bd);
  }

  if (router->onion_curve25519_pkey) {
    char kbuf[CURVE25519_BASE64_PADDED_LEN + 1];
    curve25519_public_to_base64(kbuf, router->onion_curve25519_pkey, false);
    smartlist_add_asprintf(chunks, "ntor-onion-key %s\n", kbuf);
  } else {
    /* Authorities will start rejecting relays without ntor keys in 0.2.9 */
    log_err(LD_BUG, "A relay must have an ntor onion key");
    goto err;
  }

  /* Write the exit policy to the end of 's'. */
  if (!router->exit_policy || !smartlist_len(router->exit_policy)) {
    smartlist_add_strdup(chunks, "reject *:*\n");
  } else if (router->exit_policy) {
    char *exit_policy = router_dump_exit_policy_to_string(router,1,0);

    if (!exit_policy)
      goto err;

    smartlist_add_asprintf(chunks, "%s\n", exit_policy);
    tor_free(exit_policy);
  }

  if (router->ipv6_exit_policy) {
    char *p6 = write_short_policy(router->ipv6_exit_policy);
    if (p6 && strcmp(p6, "reject 1-65535")) {
      smartlist_add_asprintf(chunks,
                            "ipv6-policy %s\n", p6);
    }
    tor_free(p6);
  }

  if (router_should_advertise_begindir(options,
                                   router->supports_tunnelled_dir_requests)) {
    smartlist_add_strdup(chunks, "tunnelled-dir-server\n");
  }

  /* Overload general information. */
  if (options->OverloadStatistics) {
    char *overload_general = rep_hist_get_overload_general_line();

    if (overload_general) {
      smartlist_add(chunks, overload_general);
    }
  }

  /* Sign the descriptor with Ed25519 */
  if (emit_ed_sigs)  {
    smartlist_add_strdup(chunks, "router-sig-ed25519 ");
    crypto_digest_smartlist_prefix(digest, DIGEST256_LEN,
                                   ED_DESC_SIGNATURE_PREFIX,
                                   chunks, "", DIGEST_SHA256);
    ed25519_signature_t sig;
    char buf[ED25519_SIG_BASE64_LEN+1];
    if (ed25519_sign(&sig, (const uint8_t*)digest, DIGEST256_LEN,
                     signing_keypair) < 0)
      goto err;
    ed25519_signature_to_base64(buf, &sig);

    smartlist_add_asprintf(chunks, "%s\n", buf);
  }

  /* Sign the descriptor with RSA */
  smartlist_add_strdup(chunks, "router-signature\n");

  crypto_digest_smartlist(digest, DIGEST_LEN, chunks, "", DIGEST_SHA1);

  {
    char *sig;
    if (!(sig = router_get_dirobj_signature(digest, DIGEST_LEN, ident_key))) {
      log_warn(LD_BUG, "Couldn't sign router descriptor");
      goto err;
    }
    smartlist_add(chunks, sig);
  }

  /* include a last '\n' */
  smartlist_add_strdup(chunks, "\n");

  output = smartlist_join_strings(chunks, "", 0, NULL);

#ifdef DEBUG_ROUTER_DUMP_ROUTER_TO_STRING
  {
    char *s_dup;
    const char *cp;
    routerinfo_t *ri_tmp;
    cp = s_dup = tor_strdup(output);
    ri_tmp = router_parse_entry_from_string(cp, NULL, 1, 0, NULL, NULL);
    if (!ri_tmp) {
      log_err(LD_BUG,
              "We just generated a router descriptor we can't parse.");
      log_err(LD_BUG, "Descriptor was: <<%s>>", output);
      goto err;
    }
    tor_free(s_dup);
    routerinfo_free(ri_tmp);
  }
#endif /* defined(DEBUG_ROUTER_DUMP_ROUTER_TO_STRING) */

  goto done;

 err:
  tor_free(output); /* sets output to NULL */
 done:
  if (chunks) {
    SMARTLIST_FOREACH(chunks, char *, cp, tor_free(cp));
    smartlist_free(chunks);
  }
  crypto_pk_free(rsa_pubkey);
  tor_free(address);
  tor_free(family_line);
  tor_free(onion_pkey);
  tor_free(identity_pkey);
  tor_free(extra_or_address);
  tor_free(ed_cert_line);
  tor_free(rsa_tap_cc_line);
  tor_free(ntor_cc_line);
  tor_free(extra_info_line);
  tor_free(proto_line);

  return output;
}

/**
 * OR only: Given <b>router</b>, produce a string with its exit policy.
 * If <b>include_ipv4</b> is true, include IPv4 entries.
 * If <b>include_ipv6</b> is true, include IPv6 entries.
 */
char *
router_dump_exit_policy_to_string(const routerinfo_t *router,
                                  int include_ipv4,
                                  int include_ipv6)
{
  if ((!router->exit_policy) || (router->policy_is_reject_star)) {
    return tor_strdup("reject *:*");
  }

  return policy_dump_to_string(router->exit_policy,
                               include_ipv4,
                               include_ipv6);
}

/** Load the contents of <b>filename</b>, find a line starting with
 * timestamp tag <b>ts_tag</b>, ensure that its timestamp is not more than 25
 * hours in the past or more than 1 hour in the future with respect to
 * <b>now</b>, and write the entire file contents into <b>out</b>.
 *
 * The timestamp expected should be an ISO-formatted UTC time value which is
 * parsed using our parse_iso_time() function.
 *
 * In case more than one tag are found in the file, the very first one is
 * used.
 *
 * Return 1 for success, 0 if the file does not exist or is empty, or -1 if
 * the file does not contain a line with the timestamp tag. */
STATIC int
load_stats_file(const char *filename, const char *ts_tag, time_t now,
                char **out)
{
  int r = -1;
  char *fname = get_datadir_fname(filename);
  char *contents = NULL, timestr[ISO_TIME_LEN+1];
  time_t written;

  switch (file_status(fname)) {
  case FN_FILE:
    contents = read_file_to_str(fname, 0, NULL);
    if (contents == NULL) {
      log_debug(LD_BUG, "Unable to read content of %s", filename);
      goto end;
    }
    /* Find the timestamp tag to validate that the file is not too old or if
     * exists. */
    const char *ts_tok = find_str_at_start_of_line(contents, ts_tag);
    if (!ts_tok) {
      log_warn(LD_BUG, "Token %s not found in file %s", ts_tag, filename);
      goto end;
    }
    /* Do we have enough for parsing a timestamp? */
    if (strlen(ts_tok) < strlen(ts_tag) + 1 + sizeof(timestr)) {
      log_warn(LD_BUG, "Token %s malformed in file %s", ts_tag, filename);
      goto end;
    }
    /* Parse timestamp in order to validate it is not too old. */
    strlcpy(timestr, ts_tok + strlen(ts_tag) + 1, sizeof(timestr));
    if (parse_iso_time(timestr, &written) < 0) {
      log_warn(LD_BUG, "Token %s has a malformed timestamp in file %s",
               ts_tag, filename);
      goto end;
    }
    if (written < now - (25*60*60) || written > now + (1*60*60)) {
      /* This can happen normally so don't log. */
      goto end;
    }
    /* Success. Put in the entire content. */
    *out = contents;
    contents = NULL; /* Must not free it. */
    r = 1;
    break;
  /* treat empty stats files as if the file doesn't exist */
  case FN_NOENT:
  case FN_EMPTY:
    r = 0;
    break;
  case FN_ERROR:
  case FN_DIR:
  default:
    break;
  }

 end:
  tor_free(fname);
  tor_free(contents);
  return r;
}

/** Add header strings to chunks, based on the extrainfo object extrainfo,
 * and ed25519 keypair signing_keypair, if emit_ed_sigs is true.
 * Helper for extrainfo_dump_to_string().
 * Returns 0 on success, negative on failure. */
static int
extrainfo_dump_to_string_header_helper(
                                     smartlist_t *chunks,
                                     const extrainfo_t *extrainfo,
                                     const ed25519_keypair_t *signing_keypair,
                                     int emit_ed_sigs)
{
  char identity[HEX_DIGEST_LEN+1];
  char published[ISO_TIME_LEN+1];
  char *ed_cert_line = NULL;
  char *pre = NULL;
  int rv = -1;

  base16_encode(identity, sizeof(identity),
                extrainfo->cache_info.identity_digest, DIGEST_LEN);
  format_iso_time(published, extrainfo->cache_info.published_on);
  if (emit_ed_sigs) {
    if (!extrainfo->cache_info.signing_key_cert->signing_key_included ||
        !ed25519_pubkey_eq(&extrainfo->cache_info.signing_key_cert->signed_key,
                           &signing_keypair->pubkey)) {
      log_warn(LD_BUG, "Tried to sign a extrainfo descriptor with a "
               "mismatched ed25519 key chain %d",
               extrainfo->cache_info.signing_key_cert->signing_key_included);
      goto err;
    }
    char ed_cert_base64[256];
    if (base64_encode(ed_cert_base64, sizeof(ed_cert_base64),
                 (const char*)extrainfo->cache_info.signing_key_cert->encoded,
                 extrainfo->cache_info.signing_key_cert->encoded_len,
                 BASE64_ENCODE_MULTILINE) < 0) {
      log_err(LD_BUG,"Couldn't base64-encode signing key certificate!");
      goto err;
    }
    tor_asprintf(&ed_cert_line, "identity-ed25519\n"
                 "-----BEGIN ED25519 CERT-----\n"
                 "%s"
                 "-----END ED25519 CERT-----\n", ed_cert_base64);
  } else {
    ed_cert_line = tor_strdup("");
  }

  /* This is the first chunk in the file. If the file is too big, other chunks
   * are removed. So we must only add one chunk here. */
  tor_asprintf(&pre, "extra-info %s %s\n%spublished %s\n",
               extrainfo->nickname, identity,
               ed_cert_line,
               published);
  smartlist_add(chunks, pre);

  rv = 0;
  goto done;

 err:
  rv = -1;

 done:
  tor_free(ed_cert_line);
  return rv;
}

/** Add pluggable transport and statistics strings to chunks, skipping
 * statistics if write_stats_to_extrainfo is false.
 * Helper for extrainfo_dump_to_string().
 * Can not fail. */
static void
extrainfo_dump_to_string_stats_helper(smartlist_t *chunks,
                                      int write_stats_to_extrainfo)
{
  const or_options_t *options = get_options();
  char *contents = NULL;
  time_t now = time(NULL);

  /* If the file is too big, these chunks are removed, starting with the last
   * chunk. So each chunk must be a complete line, and the file must be valid
   * after each chunk. */

  /* Add information about the pluggable transports we support, even if we
   * are not publishing statistics. This information is needed by BridgeDB
   * to distribute bridges. */
  if (options->ServerTransportPlugin) {
    char *pluggable_transports = pt_get_extra_info_descriptor_string();
    if (pluggable_transports)
      smartlist_add(chunks, pluggable_transports);
  }

  if (options->ExtraInfoStatistics && write_stats_to_extrainfo) {
    log_info(LD_GENERAL, "Adding stats to extra-info descriptor.");
    /* Bandwidth usage stats don't have their own option */
    {
      contents = bwhist_get_bandwidth_lines();
      smartlist_add(chunks, contents);
    }
    /* geoip hashes aren't useful unless we are publishing other stats */
    if (geoip_is_loaded(AF_INET))
      smartlist_add_asprintf(chunks, "geoip-db-digest %s\n",
                             geoip_db_digest(AF_INET));
    if (geoip_is_loaded(AF_INET6))
      smartlist_add_asprintf(chunks, "geoip6-db-digest %s\n",
                             geoip_db_digest(AF_INET6));
    if (options->DirReqStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"dirreq-stats",
                        "dirreq-stats-end", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->HiddenServiceStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"hidserv-stats",
                        "hidserv-stats-end", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->HiddenServiceStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"hidserv-v3-stats",
                        "hidserv-v3-stats-end", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->EntryStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"entry-stats",
                        "entry-stats-end", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->CellStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"buffer-stats",
                        "cell-stats-end", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->ExitPortStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"exit-stats",
                        "exit-stats-end", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->ConnDirectionStatistics &&
        load_stats_file("stats"PATH_SEPARATOR"conn-stats",
                        "conn-bi-direct", now, &contents) > 0) {
      smartlist_add(chunks, contents);
    }
    if (options->PaddingStatistics) {
      contents = rep_hist_get_padding_count_lines();
      if (contents)
        smartlist_add(chunks, contents);
    }
    if (options->OverloadStatistics) {
      contents = rep_hist_get_overload_stats_lines();
      if (contents) {
        smartlist_add(chunks, contents);
      }
    }
    /* bridge statistics */
    if (should_record_bridge_info(options)) {
      const char *bridge_stats = geoip_get_bridge_stats_extrainfo(now);
      if (bridge_stats) {
        smartlist_add_strdup(chunks, bridge_stats);
      }
    }
  }
}

/** Add an ed25519 signature of chunks to chunks, using the ed25519 keypair
 * signing_keypair.
 * Helper for extrainfo_dump_to_string().
 * Returns 0 on success, negative on failure. */
static int
extrainfo_dump_to_string_ed_sig_helper(
                                     smartlist_t *chunks,
                                     const ed25519_keypair_t *signing_keypair)
{
  char sha256_digest[DIGEST256_LEN];
  ed25519_signature_t ed_sig;
  char buf[ED25519_SIG_BASE64_LEN+1];
  int rv = -1;

  /* These are two of the three final chunks in the file. If the file is too
   * big, other chunks are removed. So we must only add two chunks here. */
  smartlist_add_strdup(chunks, "router-sig-ed25519 ");
  crypto_digest_smartlist_prefix(sha256_digest, DIGEST256_LEN,
                                 ED_DESC_SIGNATURE_PREFIX,
                                 chunks, "", DIGEST_SHA256);
  if (ed25519_sign(&ed_sig, (const uint8_t*)sha256_digest, DIGEST256_LEN,
                   signing_keypair) < 0)
    goto err;
  ed25519_signature_to_base64(buf, &ed_sig);

  smartlist_add_asprintf(chunks, "%s\n", buf);

  rv = 0;
  goto done;

 err:
  rv = -1;

 done:
  return rv;
}

/** Add an RSA signature of extrainfo_string to chunks, using the RSA key
 * ident_key.
 * Helper for extrainfo_dump_to_string().
 * Returns 0 on success, negative on failure. */
static int
extrainfo_dump_to_string_rsa_sig_helper(smartlist_t *chunks,
                                        crypto_pk_t *ident_key,
                                        const char *extrainfo_string)
{
  char sig[DIROBJ_MAX_SIG_LEN+1];
  char digest[DIGEST_LEN];
  int rv = -1;

  memset(sig, 0, sizeof(sig));
  if (router_get_extrainfo_hash(extrainfo_string, strlen(extrainfo_string),
                                digest) < 0 ||
      router_append_dirobj_signature(sig, sizeof(sig), digest, DIGEST_LEN,
                                     ident_key) < 0) {
    log_warn(LD_BUG, "Could not append signature to extra-info "
                     "descriptor.");
    goto err;
  }
  smartlist_add_strdup(chunks, sig);

  rv = 0;
  goto done;

 err:
  rv = -1;

 done:
  return rv;
}

/** Write the contents of <b>extrainfo</b>, to * *<b>s_out</b>, signing them
 * with <b>ident_key</b>.
 *
 * If ExtraInfoStatistics is 1, also write aggregated statistics and related
 * configuration data before signing. Most statistics also have an option that
 * enables or disables that particular statistic.
 *
 * Always write pluggable transport lines.
 *
 * Return 0 on success, negative on failure. */
int
extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
                         crypto_pk_t *ident_key,
                         const ed25519_keypair_t *signing_keypair)
{
  int result;
  static int write_stats_to_extrainfo = 1;
  char *s = NULL, *cp, *s_dup = NULL;
  smartlist_t *chunks = smartlist_new();
  extrainfo_t *ei_tmp = NULL;
  const int emit_ed_sigs = signing_keypair &&
    extrainfo->cache_info.signing_key_cert;
  int rv = 0;

  rv = extrainfo_dump_to_string_header_helper(chunks, extrainfo,
                                              signing_keypair,
                                              emit_ed_sigs);
  if (rv < 0)
    goto err;

  extrainfo_dump_to_string_stats_helper(chunks, write_stats_to_extrainfo);

  if (emit_ed_sigs) {
    rv = extrainfo_dump_to_string_ed_sig_helper(chunks, signing_keypair);
    if (rv < 0)
      goto err;
  }

  /* This is one of the three final chunks in the file. If the file is too big,
   * other chunks are removed. So we must only add one chunk here. */
  smartlist_add_strdup(chunks, "router-signature\n");
  s = smartlist_join_strings(chunks, "", 0, NULL);

  while (strlen(s) > MAX_EXTRAINFO_UPLOAD_SIZE - DIROBJ_MAX_SIG_LEN) {
    /* So long as there are at least two chunks (one for the initial
     * extra-info line and one for the router-signature), we can keep removing
     * things. If emit_ed_sigs is true, we also keep 2 additional chunks at the
     * end for the ed25519 signature. */
    const int required_chunks = emit_ed_sigs ? 4 : 2;
    if (smartlist_len(chunks) > required_chunks) {
      /* We remove the next-to-last or 4th-last element (remember, len-1 is the
       * last element), since we need to keep the router-signature elements. */
      int idx = smartlist_len(chunks) - required_chunks;
      char *e = smartlist_get(chunks, idx);
      smartlist_del_keeporder(chunks, idx);
      log_warn(LD_GENERAL, "We just generated an extra-info descriptor "
                           "with statistics that exceeds the 50 KB "
                           "upload limit. Removing last added "
                           "statistics.");
      tor_free(e);
      tor_free(s);
      s = smartlist_join_strings(chunks, "", 0, NULL);
    } else {
      log_warn(LD_BUG, "We just generated an extra-info descriptors that "
                       "exceeds the 50 KB upload limit.");
      goto err;
    }
  }

  rv = extrainfo_dump_to_string_rsa_sig_helper(chunks, ident_key, s);
  if (rv < 0)
    goto err;

  tor_free(s);
  s = smartlist_join_strings(chunks, "", 0, NULL);

  cp = s_dup = tor_strdup(s);
  ei_tmp = extrainfo_parse_entry_from_string(cp, NULL, 1, NULL, NULL);
  if (!ei_tmp) {
    if (write_stats_to_extrainfo) {
      log_warn(LD_GENERAL, "We just generated an extra-info descriptor "
                           "with statistics that we can't parse. Not "
                           "adding statistics to this or any future "
                           "extra-info descriptors.");
      write_stats_to_extrainfo = 0;
      result = extrainfo_dump_to_string(s_out, extrainfo, ident_key,
                                        signing_keypair);
      goto done;
    } else {
      log_warn(LD_BUG, "We just generated an extrainfo descriptor we "
                       "can't parse.");
      goto err;
    }
  }

  *s_out = s;
  s = NULL; /* prevent free */
  result = 0;
  goto done;

 err:
  result = -1;

 done:
  tor_free(s);
  SMARTLIST_FOREACH(chunks, char *, chunk, tor_free(chunk));
  smartlist_free(chunks);
  tor_free(s_dup);
  extrainfo_free(ei_tmp);

  return result;
}

/** Forget that we have issued any router-related warnings, so that we'll
 * warn again if we see the same errors. */
void
router_reset_warnings(void)
{
  if (warned_family) {
    SMARTLIST_FOREACH(warned_family, char *, cp, tor_free(cp));
    smartlist_clear(warned_family);
  }
}

/** Release all static resources held in router.c */
void
router_free_all(void)
{
  crypto_pk_free(onionkey);
  crypto_pk_free(lastonionkey);
  crypto_pk_free(server_identitykey);
  crypto_pk_free(client_identitykey);

  /* Destroying a locked mutex is undefined behaviour. This mutex may be
   * locked, because multiple threads can access it. But we need to destroy
   * it, otherwise re-initialisation will trigger undefined behaviour.
   * See #31735 for details. */
  tor_mutex_free(key_lock);
  routerinfo_free(desc_routerinfo);
  extrainfo_free(desc_extrainfo);
  crypto_pk_free(authority_signing_key);
  authority_cert_free(authority_key_certificate);
  crypto_pk_free(legacy_signing_key);
  authority_cert_free(legacy_key_certificate);

  memwipe(&curve25519_onion_key, 0, sizeof(curve25519_onion_key));
  memwipe(&last_curve25519_onion_key, 0, sizeof(last_curve25519_onion_key));

  if (warned_family) {
    SMARTLIST_FOREACH(warned_family, char *, cp, tor_free(cp));
    smartlist_free(warned_family);
  }
}

/* From the given RSA key object, convert it to ASN-1 encoded format and set
 * the newly allocated object in onion_pkey_out. The length of the key is set
 * in onion_pkey_len_out. */
void
router_set_rsa_onion_pkey(const crypto_pk_t *pk, char **onion_pkey_out,
                          size_t *onion_pkey_len_out)
{
  int len;
  char buf[1024];

  tor_assert(pk);
  tor_assert(onion_pkey_out);
  tor_assert(onion_pkey_len_out);

  len = crypto_pk_asn1_encode(pk, buf, sizeof(buf));
  if (BUG(len < 0)) {
    goto done;
  }

  *onion_pkey_out = tor_memdup(buf, len);
  *onion_pkey_len_out = len;

 done:
  return;
}

/* From an ASN-1 encoded onion pkey, return a newly allocated RSA key object.
 * It is the caller's responsibility to free the returned object.
 *
 * Return NULL if the pkey is NULL, malformed or if the length is 0. */
crypto_pk_t *
router_get_rsa_onion_pkey(const char *pkey, size_t pkey_len)
{
  if (!pkey || pkey_len == 0) {
    return NULL;
  }
  return crypto_pk_asn1_decode(pkey, pkey_len);
}