tor

router.c (125480B)

---

/* 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 TAP onion key.  Requires that the onion key has been
* loaded or generated.
*
* Note that this key is no longer used for anything; we only keep it around
* because (as of June 2024) other Tor instances all expect to find it in
* our routerdescs.
**/
MOCK_IMPL(crypto_pk_t *,
get_onion_key,(void))
{
 tor_assert(onionkey);
 return onionkey;
}

/**
* Return true iff we should include our TAP onion key in our router
* descriptor.
*/
static int
should_publish_tap_onion_key(void)
{
#define SHOULD_PUBLISH_TAP_MIN 0
#define SHOULD_PUBLISH_TAP_MAX 1
 /* Note that we err on the side of publishing. */
#define SHOULD_PUBLISH_TAP_DFLT 1

 return networkstatus_get_param(NULL,
                                "publish-dummy-tap-key",
                                SHOULD_PUBLISH_TAP_DFLT,
                                SHOULD_PUBLISH_TAP_MIN,
                                SHOULD_PUBLISH_TAP_MAX);
}

/** 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);
 }
 pt_update_bridge_lines();
}

#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.
*
* Return true on success, else false on error.
*/
bool
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;
 bool result = false;
 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);
 result = true;
 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);
 return result;
}

/** 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/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)
{
#ifdef ENABLE_MODULE_RELAY
 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);
#endif
}

/** 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 %sfingerprint 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;

 if (options->command == CMD_RUN_TOR) {
   if (load_family_id_keys(options, networkstatus_get_latest_consensus()) < 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.
* 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)
{
 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 being a dir cache 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 begindir: "
                        "effective bwrate: %u, AccountingMax: %"PRIu64", "
                        "accounting interval length %d",
                        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) {
     log_notice(LD_DIR, "Advertising directory service support");
   } else {
     tor_assert(reason);
     log_notice(LD_DIR, "Not advertising Directory Service support "
                "(Reason: %s)", 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 begindir support, else
* return 1.
*
* 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,
                            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 (!supports_tunnelled_dir_requests)
   return 0;
 if (authdir_mode(options)) /* always publish */
   return 1;
 if (net_is_disabled())
   return 0;
 if (!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);
}

/** 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)
{
 return decide_to_advertise_dir_impl(options,
                                     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 are an authoritative directory server, or 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 is reachable from the outside.
*/
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;
   }
 }
 return 1; /* everything looks good! publish. */
}

/** 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);

 if (should_publish_tap_onion_key()) {
   /* get_onion_key() must invoke from main thread */
   router_set_rsa_onion_pkey(get_onion_key(), &ri->tap_onion_pkey,
                             &ri->tap_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;

 warn_about_family_id_config(get_options(), ns);
}

/**
* Return true if the parameters in `ns` say that we should publish
* a legacy family list.
*
* Use the latest networkstatus (or returns the default) if `ns` is NULL.
*/
bool
should_publish_family_list(const networkstatus_t *ns)
{
 return networkstatus_get_param(ns, "publish-family-list",
                                1, 0, 1); // default, min, max
}

/** 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->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=0, 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->tap_onion_pkey,
                                        router->tap_onion_pkey_len);
 if (rsa_pubkey) {
   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 && rsa_pubkey && 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"
                   "%s%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?"onion-key\n":"", onion_pkey?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");

 SMARTLIST_FOREACH_BEGIN(get_current_family_id_keys(),
                         const ed25519_keypair_t *, k_family_id) {
   // TODO PROP321: We may want this to be configurable;
   // we can probably use a smaller value.
#define FAMILY_CERT_LIFETIME (30*86400)
   tor_cert_t *family_cert = tor_cert_create_ed25519(
         k_family_id,
         CERT_TYPE_FAMILY_V_IDENTITY,
         // (this is the identity key "KP_relayid_ed")
         &router->cache_info.signing_key_cert->signing_key,
         router->cache_info.published_on,
         FAMILY_CERT_LIFETIME, CERT_FLAG_INCLUDE_SIGNING_KEY);
   char family_cert_base64[256];
   if (base64_encode(family_cert_base64, sizeof(family_cert_base64),
                     (const char*) family_cert->encoded,
                     family_cert->encoded_len, BASE64_ENCODE_MULTILINE) < 0) {
     log_err(LD_BUG, "Base64 encoding family cert failed!?");
     tor_cert_free(family_cert);
     goto err;
   }
   smartlist_add_asprintf(chunks,
                          "family-cert\n"
                          "-----BEGIN FAMILY CERT-----\n"
                          "%s"
                          "-----END FAMILY CERT-----\n",
                          family_cert_base64);
   tor_cert_free(family_cert);
 } SMARTLIST_FOREACH_END(k_family_id);

 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);
}