fmt_routerstatus.c

/* 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 */
 
/**
 * \file fmt_routerstatus.h
 * \brief Format routerstatus entries for controller, vote, or consensus.
 *
 * (Because controllers consume this format, we can't make this
 * code dirauth-only.)
 **/
 
#include "core/or/or.h"
#include "feature/nodelist/fmt_routerstatus.h"
 
#include "core/or/policies.h"
#include "feature/dirauth/dirvote.h"
#include "feature/nodelist/routerinfo_st.h"
#include "feature/nodelist/routerlist.h"
#include "feature/nodelist/vote_routerstatus_st.h"
#include "feature/stats/rephist.h"
 
#include "lib/crypt_ops/crypto_format.h"
 
/** Helper: write the router-status information in <b>rs</b> into a newly
 * allocated character buffer.  Use the same format as in network-status
 * documents.  If <b>version</b> is non-NULL, add a "v" line for the platform.
 * If <b>declared_publish_time</b> is nonnegative, we declare it as the
 * publication time.  Otherwise we look for a publication time in <b>vrs</b>,
 * and fall back to a default (not useful) publication time.
 *
 * Return 0 on success, -1 on failure.
 *
 * The format argument has one of the following values:
 *   NS_V2 - Output an entry suitable for a V2 NS opinion document
 *   NS_V3_CONSENSUS - Output the first portion of a V3 NS consensus entry
 *        for consensus_method.
 *   NS_V3_CONSENSUS_MICRODESC - Output the first portion of a V3 microdesc
 *        consensus entry for consensus_method.
 *   NS_V3_VOTE - Output a complete V3 NS vote. If <b>vrs</b> is present,
 *        it contains additional information for the vote.
 *   NS_CONTROL_PORT - Output a NS document for the control port.
 *
 */
char *
routerstatus_format_entry(const routerstatus_t *rs, const char *version,
                          const char *protocols,
                          routerstatus_format_type_t format,
                          const vote_routerstatus_t *vrs,
                          time_t declared_publish_time)
{
  char *summary;
  char *result = NULL;
 
  char published[ISO_TIME_LEN+1];
  char identity64[BASE64_DIGEST_LEN+1];
  char digest64[BASE64_DIGEST_LEN+1];
  smartlist_t *chunks = smartlist_new();
 
  if (declared_publish_time >= 0) {
    format_iso_time(published, declared_publish_time);
  } else if (vrs) {
    format_iso_time(published, vrs->published_on);
  } else {
    strlcpy(published, "2038-01-01 00:00:00", sizeof(published));
  }
 
  const char *ip_str = fmt_addr(&rs->ipv4_addr);
  if (ip_str[0] == '\0')
    goto err;
 
  digest_to_base64(identity64, rs->identity_digest);
  digest_to_base64(digest64, rs->descriptor_digest);
 
  smartlist_add_asprintf(chunks,
                   "r %s %s %s%s%s %s %" PRIu16 " %" PRIu16 "\n",
                   rs->nickname,
                   identity64,
                   (format==NS_V3_CONSENSUS_MICRODESC)?"":digest64,
                   (format==NS_V3_CONSENSUS_MICRODESC)?"":" ",
                   published,
                   ip_str,
                   rs->ipv4_orport,
                   rs->ipv4_dirport);
 
  /* TODO: Maybe we want to pass in what we need to build the rest of
   * this here, instead of in the caller. Then we could use the
   * networkstatus_type_t values, with an additional control port value
   * added -MP */
 
  /* Possible "a" line. At most one for now. */
  if (!tor_addr_is_null(&rs->ipv6_addr)) {
    smartlist_add_asprintf(chunks, "a %s\n",
                           fmt_addrport(&rs->ipv6_addr, rs->ipv6_orport));
  }
 
  if (format == NS_V3_CONSENSUS || format == NS_V3_CONSENSUS_MICRODESC)
    goto done;
 
  smartlist_add_asprintf(chunks,
                   "s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
                  /* These must stay in alphabetical order. */
                   rs->is_authority?" Authority":"",
                   rs->is_bad_exit?" BadExit":"",
                   rs->is_exit?" Exit":"",
                   rs->is_fast?" Fast":"",
                   rs->is_possible_guard?" Guard":"",
                   rs->is_hs_dir?" HSDir":"",
                   rs->is_middle_only?" MiddleOnly":"",
                   rs->is_flagged_running?" Running":"",
                   rs->is_stable?" Stable":"",
                   rs->is_staledesc?" StaleDesc":"",
                   rs->is_sybil?" Sybil":"",
                   rs->is_v2_dir?" V2Dir":"",
                   rs->is_valid?" Valid":"");
 
  /* length of "opt v \n" */
#define V_LINE_OVERHEAD 7
  if (version && strlen(version) < MAX_V_LINE_LEN - V_LINE_OVERHEAD) {
    smartlist_add_asprintf(chunks, "v %s\n", version);
  }
  if (protocols) {
    smartlist_add_asprintf(chunks, "pr %s\n", protocols);
  }
 
  if (format != NS_V2) {
    const routerinfo_t* desc = router_get_by_id_digest(rs->identity_digest);
    uint32_t bw_kb;
 
    if (format != NS_CONTROL_PORT) {
      /* Blow up more or less nicely if we didn't get anything or not the
       * thing we expected.
       * This should be kept in sync with the function
       * routerstatus_has_visibly_changed and the struct routerstatus_t
       */
      if (!desc) {
        char id[HEX_DIGEST_LEN+1];
        char dd[HEX_DIGEST_LEN+1];
 
        base16_encode(id, sizeof(id), rs->identity_digest, DIGEST_LEN);
        base16_encode(dd, sizeof(dd), rs->descriptor_digest, DIGEST_LEN);
        log_warn(LD_BUG, "Cannot get any descriptor for %s "
            "(wanted descriptor %s).",
            id, dd);
        goto err;
      }
 
      /* This assert could fire for the control port, because
       * it can request NS documents before all descriptors
       * have been fetched. Therefore, we only do this test when
       * format != NS_CONTROL_PORT. */
      if (tor_memneq(desc->cache_info.signed_descriptor_digest,
            rs->descriptor_digest,
            DIGEST_LEN)) {
        char rl_d[HEX_DIGEST_LEN+1];
        char rs_d[HEX_DIGEST_LEN+1];
        char id[HEX_DIGEST_LEN+1];
 
        base16_encode(rl_d, sizeof(rl_d),
            desc->cache_info.signed_descriptor_digest, DIGEST_LEN);
        base16_encode(rs_d, sizeof(rs_d), rs->descriptor_digest, DIGEST_LEN);
        base16_encode(id, sizeof(id), rs->identity_digest, DIGEST_LEN);
        log_err(LD_BUG, "descriptor digest in routerlist does not match "
            "the one in routerstatus: %s vs %s "
            "(router %s)\n",
            rl_d, rs_d, id);
 
        tor_assert(tor_memeq(desc->cache_info.signed_descriptor_digest,
              rs->descriptor_digest,
              DIGEST_LEN));
      }
    }
 
    if (format == NS_CONTROL_PORT && rs->has_bandwidth) {
      bw_kb = rs->bandwidth_kb;
    } else {
      tor_assert(desc);
      bw_kb = router_get_advertised_bandwidth_capped(desc) / 1000;
    }
    smartlist_add_asprintf(chunks,
                     "w Bandwidth=%d", bw_kb);
 
    /* Include the bandwidth weight from our external bandwidth
     * authority, if we have one. */
    if (format == NS_V3_VOTE && vrs && vrs->has_measured_bw) {
      if (!rs->is_authority) { /* normal case */
        smartlist_add_asprintf(chunks,
                         " Measured=%d", vrs->measured_bw_kb);
      } else {
       /* dir auth special case: don't give it a Measured line, so we
        * can reserve its attention for authority-specific activities.
        * But do include the bwauth's opinion so it can be recorded for
        * posterity. See #40698 for details. */
        smartlist_add_asprintf(chunks,
                         " MeasuredButAuthority=%d", vrs->measured_bw_kb);
      }
    }
    /* Write down guardfraction information if we have it. */
    if (format == NS_V3_VOTE && vrs && vrs->status.has_guardfraction) {
      smartlist_add_asprintf(chunks,
                             " GuardFraction=%d",
                             vrs->status.guardfraction_percentage);
    }
 
    smartlist_add_strdup(chunks, "\n");
 
    if (desc) {
      summary = policy_summarize(desc->exit_policy, AF_INET);
      smartlist_add_asprintf(chunks, "p %s\n", summary);
      tor_free(summary);
    }
 
    if (format == NS_V3_VOTE && vrs) {
      if (fast_mem_is_zero((char*)vrs->ed25519_id, ED25519_PUBKEY_LEN)) {
        smartlist_add_strdup(chunks, "id ed25519 none\n");
      } else {
        char ed_b64[BASE64_DIGEST256_LEN+1];
        digest256_to_base64(ed_b64, (const char*)vrs->ed25519_id);
        smartlist_add_asprintf(chunks, "id ed25519 %s\n", ed_b64);
      }
 
      /* We'll add a series of statistics to the vote per relays so we are
       * able to assess what each authorities sees and help our health and
       * performance work. */
      time_t now = time(NULL);
      smartlist_add_asprintf(chunks, "stats wfu=%.6f tk=%lu mtbf=%.0f\n",
        rep_hist_get_weighted_fractional_uptime(rs->identity_digest, now),
        rep_hist_get_weighted_time_known(rs->identity_digest, now),
        rep_hist_get_stability(rs->identity_digest, now));
    }
  }
 
 done:
  result = smartlist_join_strings(chunks, "", 0, NULL);
 
 err:
  SMARTLIST_FOREACH(chunks, char *, cp, tor_free(cp));
  smartlist_free(chunks);
 
  return result;
}