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[tor-commits] [tor/maint-0.4.0] Merge branch 'bug29706_034_minimal_merge' into bug29706_035_minimal_merge



commit 55865a2c9c9929b690a4f5a969afd5d4415c40bd
Merge: 5d41e2223 aec6ee201
Author: teor <teor@xxxxxxxxxxxxxx>
Date:   Mon Mar 18 11:29:20 2019 +1000

    Merge branch 'bug29706_034_minimal_merge' into bug29706_035_minimal_merge

 changes/bug29706_minimal                  |  4 ++++
 src/feature/dirauth/shared_random_state.c |  4 ++--
 src/feature/dirauth/shared_random_state.h |  2 ++
 src/test/test_shared_random.c             | 17 ++++++++++++++---
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --cc src/feature/dirauth/shared_random_state.c
index 2bc030f4a,000000000..b3e4a4ef9
mode 100644,000000..100644
--- a/src/feature/dirauth/shared_random_state.c
+++ b/src/feature/dirauth/shared_random_state.c
@@@ -1,1340 -1,0 +1,1340 @@@
 +/* Copyright (c) 2016-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file shared_random_state.c
 + *
 + * \brief Functions and data structures for the state of the random protocol
 + *        as defined in proposal #250.
 + **/
 +
 +#define SHARED_RANDOM_STATE_PRIVATE
 +
 +#include "core/or/or.h"
 +#include "app/config/config.h"
 +#include "app/config/confparse.h"
 +#include "lib/crypt_ops/crypto_util.h"
 +#include "feature/dirauth/dirvote.h"
 +#include "feature/nodelist/networkstatus.h"
 +#include "feature/relay/router.h"
 +#include "feature/dirauth/shared_random.h"
 +#include "feature/hs_common/shared_random_client.h"
 +#include "feature/dirauth/shared_random_state.h"
 +#include "feature/dircommon/voting_schedule.h"
 +#include "lib/encoding/confline.h"
 +
 +#include "app/config/or_state_st.h"
 +
 +/* Default filename of the shared random state on disk. */
 +static const char default_fname[] = "sr-state";
 +
 +/* String representation of a protocol phase. */
 +static const char *phase_str[] = { "unknown", "commit", "reveal" };
 +
 +/* Our shared random protocol state. There is only one possible state per
 + * protocol run so this is the global state which is reset at every run once
 + * the shared random value has been computed. */
 +static sr_state_t *sr_state = NULL;
 +
 +/* Representation of our persistent state on disk. The sr_state above
 + * contains the data parsed from this state. When we save to disk, we
 + * translate the sr_state to this sr_disk_state. */
 +static sr_disk_state_t *sr_disk_state = NULL;
 +
 +/* Disk state file keys. */
 +static const char dstate_commit_key[] = "Commit";
 +static const char dstate_prev_srv_key[] = "SharedRandPreviousValue";
 +static const char dstate_cur_srv_key[] = "SharedRandCurrentValue";
 +
 +/** dummy instance of sr_disk_state_t, used for type-checking its
 + * members with CONF_CHECK_VAR_TYPE. */
 +DUMMY_TYPECHECK_INSTANCE(sr_disk_state_t);
 +
 +/* These next two are duplicates or near-duplicates from config.c */
 +#define VAR(name, conftype, member, initvalue)                              \
 +  { name, CONFIG_TYPE_ ## conftype, offsetof(sr_disk_state_t, member),      \
 +      initvalue CONF_TEST_MEMBERS(sr_disk_state_t, conftype, member) }
 +/* As VAR, but the option name and member name are the same. */
 +#define V(member, conftype, initvalue) \
 +  VAR(#member, conftype, member, initvalue)
 +/* Our persistent state magic number. */
 +#define SR_DISK_STATE_MAGIC 0x98AB1254
 +
 +static int
 +disk_state_validate_cb(void *old_state, void *state, void *default_state,
 +                       int from_setconf, char **msg);
 +static void disk_state_free_cb(void *);
 +
 +/* Array of variables that are saved to disk as a persistent state. */
 +static config_var_t state_vars[] = {
 +  V(Version,                    UINT, "0"),
 +  V(TorVersion,                 STRING, NULL),
 +  V(ValidAfter,                 ISOTIME, NULL),
 +  V(ValidUntil,                 ISOTIME, NULL),
 +
 +  V(Commit,                     LINELIST, NULL),
 +
 +  V(SharedRandValues,           LINELIST_V, NULL),
 +  VAR("SharedRandPreviousValue",LINELIST_S, SharedRandValues, NULL),
 +  VAR("SharedRandCurrentValue", LINELIST_S, SharedRandValues, NULL),
 +  END_OF_CONFIG_VARS
 +};
 +
 +/* "Extra" variable in the state that receives lines we can't parse. This
 + * lets us preserve options from versions of Tor newer than us. */
 +static config_var_t state_extra_var = {
 +  "__extra", CONFIG_TYPE_LINELIST,
 +  offsetof(sr_disk_state_t, ExtraLines), NULL
 +  CONF_TEST_MEMBERS(sr_disk_state_t, LINELIST, ExtraLines)
 +};
 +
 +/* Configuration format of sr_disk_state_t. */
 +static const config_format_t state_format = {
 +  sizeof(sr_disk_state_t),
 +  SR_DISK_STATE_MAGIC,
 +  offsetof(sr_disk_state_t, magic_),
 +  NULL,
 +  NULL,
 +  state_vars,
 +  disk_state_validate_cb,
 +  disk_state_free_cb,
 +  &state_extra_var,
 +};
 +
 +/* Return a string representation of a protocol phase. */
 +STATIC const char *
 +get_phase_str(sr_phase_t phase)
 +{
 +  const char *the_string = NULL;
 +
 +  switch (phase) {
 +  case SR_PHASE_COMMIT:
 +  case SR_PHASE_REVEAL:
 +    the_string = phase_str[phase];
 +    break;
 +  default:
 +    /* Unknown phase shouldn't be possible. */
 +    tor_assert(0);
 +  }
 +
 +  return the_string;
 +}
 +/* Return the time we should expire the state file created at <b>now</b>.
 + * We expire the state file in the beginning of the next protocol run. */
 +STATIC time_t
 +get_state_valid_until_time(time_t now)
 +{
 +  int total_rounds = SHARED_RANDOM_N_ROUNDS * SHARED_RANDOM_N_PHASES;
 +  int current_round, voting_interval, rounds_left;
 +  time_t valid_until, beginning_of_current_round;
 +
 +  voting_interval = get_voting_interval();
 +  /* Find the time the current round started. */
 +  beginning_of_current_round = get_start_time_of_current_round();
 +
 +  /* Find how many rounds are left till the end of the protocol run */
 +  current_round = (now / voting_interval) % total_rounds;
 +  rounds_left = total_rounds - current_round;
 +
 +  /* To find the valid-until time now, take the start time of the current
 +   * round and add to it the time it takes for the leftover rounds to
 +   * complete. */
 +  valid_until = beginning_of_current_round + (rounds_left * voting_interval);
 +
 +  { /* Logging */
 +    char tbuf[ISO_TIME_LEN + 1];
 +    format_iso_time(tbuf, valid_until);
 +    log_debug(LD_DIR, "SR: Valid until time for state set to %s.", tbuf);
 +  }
 +
 +  return valid_until;
 +}
 +
 +/* Given the consensus 'valid-after' time, return the protocol phase we should
 + * be in. */
 +STATIC sr_phase_t
 +get_sr_protocol_phase(time_t valid_after)
 +{
 +  /* Shared random protocol has two phases, commit and reveal. */
 +  int total_periods = SHARED_RANDOM_N_ROUNDS * SHARED_RANDOM_N_PHASES;
 +  int current_slot;
 +
 +  /* Split time into slots of size 'voting_interval'. See which slot we are
 +   * currently into, and find which phase it corresponds to. */
 +  current_slot = (valid_after / get_voting_interval()) % total_periods;
 +
 +  if (current_slot < SHARED_RANDOM_N_ROUNDS) {
 +    return SR_PHASE_COMMIT;
 +  } else {
 +    return SR_PHASE_REVEAL;
 +  }
 +}
 +
 +/* Add the given <b>commit</b> to <b>state</b>. It MUST be a valid commit
 + * and there shouldn't be a commit from the same authority in the state
 + * already else verification hasn't been done prior. This takes ownership of
 + * the commit once in our state. */
 +static void
 +commit_add_to_state(sr_commit_t *commit, sr_state_t *state)
 +{
 +  sr_commit_t *saved_commit;
 +
 +  tor_assert(commit);
 +  tor_assert(state);
 +
 +  saved_commit = digestmap_set(state->commits, commit->rsa_identity,
 +                               commit);
 +  if (saved_commit != NULL) {
 +    /* This means we already have that commit in our state so adding twice
 +     * the same commit is either a code flow error, a corrupted disk state
 +     * or some new unknown issue. */
 +    log_warn(LD_DIR, "SR: Commit from %s exists in our state while "
 +                     "adding it: '%s'", sr_commit_get_rsa_fpr(commit),
 +                     commit->encoded_commit);
 +    sr_commit_free(saved_commit);
 +  }
 +}
 +
 +/* Helper: deallocate a commit object. (Used with digestmap_free(), which
 + * requires a function pointer whose argument is void *). */
 +static void
 +commit_free_(void *p)
 +{
 +  sr_commit_free_(p);
 +}
 +
 +#define state_free(val) \
 +  FREE_AND_NULL(sr_state_t, state_free_, (val))
 +
 +/* Free a state that was allocated with state_new(). */
 +static void
 +state_free_(sr_state_t *state)
 +{
 +  if (state == NULL) {
 +    return;
 +  }
 +  tor_free(state->fname);
 +  digestmap_free(state->commits, commit_free_);
 +  tor_free(state->current_srv);
 +  tor_free(state->previous_srv);
 +  tor_free(state);
 +}
 +
 +/* Allocate an sr_state_t object and returns it. If no <b>fname</b>, the
 + * default file name is used. This function does NOT initialize the state
 + * timestamp, phase or shared random value. NULL is never returned. */
 +static sr_state_t *
 +state_new(const char *fname, time_t now)
 +{
 +  sr_state_t *new_state = tor_malloc_zero(sizeof(*new_state));
 +  /* If file name is not provided, use default. */
 +  if (fname == NULL) {
 +    fname = default_fname;
 +  }
 +  new_state->fname = tor_strdup(fname);
 +  new_state->version = SR_PROTO_VERSION;
 +  new_state->commits = digestmap_new();
 +  new_state->phase = get_sr_protocol_phase(now);
 +  new_state->valid_until = get_state_valid_until_time(now);
 +  return new_state;
 +}
 +
 +/* Set our global state pointer with the one given. */
 +static void
 +state_set(sr_state_t *state)
 +{
 +  tor_assert(state);
 +  if (sr_state != NULL) {
 +    state_free(sr_state);
 +  }
 +  sr_state = state;
 +}
 +
 +#define disk_state_free(val) \
 +  FREE_AND_NULL(sr_disk_state_t, disk_state_free_, (val))
 +
 +/* Free an allocated disk state. */
 +static void
 +disk_state_free_(sr_disk_state_t *state)
 +{
 +  if (state == NULL) {
 +    return;
 +  }
 +  config_free(&state_format, state);
 +}
 +
 +/* Allocate a new disk state, initialize it and return it. */
 +static sr_disk_state_t *
 +disk_state_new(time_t now)
 +{
 +  sr_disk_state_t *new_state = tor_malloc_zero(sizeof(*new_state));
 +
 +  new_state->magic_ = SR_DISK_STATE_MAGIC;
 +  new_state->Version = SR_PROTO_VERSION;
 +  new_state->TorVersion = tor_strdup(get_version());
 +  new_state->ValidUntil = get_state_valid_until_time(now);
 +  new_state->ValidAfter = now;
 +
 +  /* Init config format. */
 +  config_init(&state_format, new_state);
 +  return new_state;
 +}
 +
 +/* Set our global disk state with the given state. */
 +static void
 +disk_state_set(sr_disk_state_t *state)
 +{
 +  tor_assert(state);
 +  if (sr_disk_state != NULL) {
 +    disk_state_free(sr_disk_state);
 +  }
 +  sr_disk_state = state;
 +}
 +
 +/* Return -1 if the disk state is invalid (something in there that we can't or
 + * shouldn't use). Return 0 if everything checks out. */
 +static int
 +disk_state_validate(const sr_disk_state_t *state)
 +{
 +  time_t now;
 +
 +  tor_assert(state);
 +
 +  /* Do we support the protocol version in the state or is it 0 meaning
 +   * Version wasn't found in the state file or bad anyway ? */
 +  if (state->Version == 0 || state->Version > SR_PROTO_VERSION) {
 +    goto invalid;
 +  }
 +
 +  /* If the valid until time is before now, we shouldn't use that state. */
 +  now = time(NULL);
 +  if (state->ValidUntil < now) {
 +    log_info(LD_DIR, "SR: Disk state has expired. Ignoring it.");
 +    goto invalid;
 +  }
 +
 +  /* Make sure we don't have a valid after time that is earlier than a valid
 +   * until time which would make things not work well. */
 +  if (state->ValidAfter >= state->ValidUntil) {
 +    log_info(LD_DIR, "SR: Disk state valid after/until times are invalid.");
 +    goto invalid;
 +  }
 +
 +  return 0;
 +
 + invalid:
 +  return -1;
 +}
 +
 +/* Validate the disk state (NOP for now). */
 +static int
 +disk_state_validate_cb(void *old_state, void *state, void *default_state,
 +                       int from_setconf, char **msg)
 +{
 +  /* We don't use these; only options do. */
 +  (void) from_setconf;
 +  (void) default_state;
 +  (void) old_state;
 +
 +  /* This is called by config_dump which is just before we are about to
 +   * write it to disk. At that point, our global memory state has been
 +   * copied to the disk state so it's fair to assume it's trustable. */
 +  (void) state;
 +  (void) msg;
 +  return 0;
 +}
 +
 +static void
 +disk_state_free_cb(void *state)
 +{
 +  disk_state_free_(state);
 +}
 +
 +/* Parse the Commit line(s) in the disk state and translate them to the
 + * the memory state. Return 0 on success else -1 on error. */
 +static int
 +disk_state_parse_commits(sr_state_t *state,
 +                         const sr_disk_state_t *disk_state)
 +{
 +  config_line_t *line;
 +  smartlist_t *args = NULL;
 +
 +  tor_assert(state);
 +  tor_assert(disk_state);
 +
 +  for (line = disk_state->Commit; line; line = line->next) {
 +    sr_commit_t *commit = NULL;
 +
 +    /* Extra safety. */
 +    if (strcasecmp(line->key, dstate_commit_key) ||
 +        line->value == NULL) {
 +      /* Ignore any lines that are not commits. */
 +      tor_fragile_assert();
 +      continue;
 +    }
 +    args = smartlist_new();
 +    smartlist_split_string(args, line->value, " ",
 +                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
 +    if (smartlist_len(args) < 3) {
 +      log_warn(LD_BUG, "SR: Too few arguments in Commit Line: %s",
 +               escaped(line->value));
 +      goto error;
 +    }
 +    commit = sr_parse_commit(args);
 +    if (commit == NULL) {
 +      /* Ignore badly formed commit. It could also be a authority
 +       * fingerprint that we don't know about so it shouldn't be used. */
 +      smartlist_free(args);
 +      continue;
 +    }
 +    /* We consider parseable commit from our disk state to be valid because
 +     * they need to be in the first place to get in there. */
 +    commit->valid = 1;
 +    /* Add commit to our state pointer. */
 +    commit_add_to_state(commit, state);
 +
 +    SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
 +    smartlist_free(args);
 +  }
 +
 +  return 0;
 +
 + error:
 +  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
 +  smartlist_free(args);
 +  return -1;
 +}
 +
 +/* Parse a share random value line from the disk state and save it to dst
 + * which is an allocated srv object. Return 0 on success else -1. */
 +static int
 +disk_state_parse_srv(const char *value, sr_srv_t *dst)
 +{
 +  int ret = -1;
 +  smartlist_t *args;
 +  sr_srv_t *srv;
 +
 +  tor_assert(value);
 +  tor_assert(dst);
 +
 +  args = smartlist_new();
 +  smartlist_split_string(args, value, " ",
 +                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
 +  if (smartlist_len(args) < 2) {
 +    log_warn(LD_BUG, "SR: Too few arguments in shared random value. "
 +             "Line: %s", escaped(value));
 +    goto error;
 +  }
 +  srv = sr_parse_srv(args);
 +  if (srv == NULL) {
 +    goto error;
 +  }
 +  dst->num_reveals = srv->num_reveals;
 +  memcpy(dst->value, srv->value, sizeof(dst->value));
 +  tor_free(srv);
 +  ret = 0;
 +
 + error:
 +  SMARTLIST_FOREACH(args, char *, s, tor_free(s));
 +  smartlist_free(args);
 +  return ret;
 +}
 +
 +/* Parse both SharedRandCurrentValue and SharedRandPreviousValue line from
 + * the state. Return 0 on success else -1. */
 +static int
 +disk_state_parse_sr_values(sr_state_t *state,
 +                           const sr_disk_state_t *disk_state)
 +{
 +  /* Only one value per type (current or previous) is allowed so we keep
 +   * track of it with these flag. */
 +  unsigned int seen_previous = 0, seen_current = 0;
 +  config_line_t *line;
 +  sr_srv_t *srv = NULL;
 +
 +  tor_assert(state);
 +  tor_assert(disk_state);
 +
 +  for (line = disk_state->SharedRandValues; line; line = line->next) {
 +    if (line->value == NULL) {
 +      continue;
 +    }
 +    srv = tor_malloc_zero(sizeof(*srv));
 +    if (disk_state_parse_srv(line->value, srv) < 0) {
 +      log_warn(LD_BUG, "SR: Broken current SRV line in state %s",
 +               escaped(line->value));
 +      goto bad;
 +    }
 +    if (!strcasecmp(line->key, dstate_prev_srv_key)) {
 +      if (seen_previous) {
 +        log_warn(LD_DIR, "SR: Second previous SRV value seen. Bad state");
 +        goto bad;
 +      }
 +      state->previous_srv = srv;
 +      seen_previous = 1;
 +    } else if (!strcasecmp(line->key, dstate_cur_srv_key)) {
 +      if (seen_current) {
 +        log_warn(LD_DIR, "SR: Second current SRV value seen. Bad state");
 +        goto bad;
 +      }
 +      state->current_srv = srv;
 +      seen_current = 1;
 +    } else {
 +      /* Unknown key. Ignoring. */
 +      tor_free(srv);
 +    }
 +  }
 +
 +  return 0;
 + bad:
 +  tor_free(srv);
 +  return -1;
 +}
 +
 +/* Parse the given disk state and set a newly allocated state. On success,
 + * return that state else NULL. */
 +static sr_state_t *
 +disk_state_parse(const sr_disk_state_t *new_disk_state)
 +{
 +  sr_state_t *new_state = state_new(default_fname, time(NULL));
 +
 +  tor_assert(new_disk_state);
 +
 +  new_state->version = new_disk_state->Version;
 +  new_state->valid_until = new_disk_state->ValidUntil;
 +  new_state->valid_after = new_disk_state->ValidAfter;
 +
 +  /* Set our current phase according to the valid-after time in our disk
 +   * state. The disk state we are parsing contains everything for the phase
 +   * starting at valid_after so make sure our phase reflects that. */
 +  new_state->phase = get_sr_protocol_phase(new_state->valid_after);
 +
 +  /* Parse the shared random values. */
 +  if (disk_state_parse_sr_values(new_state, new_disk_state) < 0) {
 +    goto error;
 +  }
 +  /* Parse the commits. */
 +  if (disk_state_parse_commits(new_state, new_disk_state) < 0) {
 +    goto error;
 +  }
 +  /* Great! This new state contains everything we had on disk. */
 +  return new_state;
 +
 + error:
 +  state_free(new_state);
 +  return NULL;
 +}
 +
 +/* From a valid commit object and an allocated config line, set the line's
 + * value to the state string representation of a commit. */
 +static void
 +disk_state_put_commit_line(const sr_commit_t *commit, config_line_t *line)
 +{
 +  char *reveal_str = NULL;
 +
 +  tor_assert(commit);
 +  tor_assert(line);
 +
 +  if (!tor_mem_is_zero(commit->encoded_reveal,
 +                       sizeof(commit->encoded_reveal))) {
 +    /* Add extra whitespace so we can format the line correctly. */
 +    tor_asprintf(&reveal_str, " %s", commit->encoded_reveal);
 +  }
 +  tor_asprintf(&line->value, "%u %s %s %s%s",
 +               SR_PROTO_VERSION,
 +               crypto_digest_algorithm_get_name(commit->alg),
 +               sr_commit_get_rsa_fpr(commit),
 +               commit->encoded_commit,
 +               reveal_str != NULL ? reveal_str : "");
 +  if (reveal_str != NULL) {
 +    memwipe(reveal_str, 0, strlen(reveal_str));
 +    tor_free(reveal_str);
 +  }
 +}
 +
 +/* From a valid srv object and an allocated config line, set the line's
 + * value to the state string representation of a shared random value. */
 +static void
 +disk_state_put_srv_line(const sr_srv_t *srv, config_line_t *line)
 +{
 +  char encoded[SR_SRV_VALUE_BASE64_LEN + 1];
 +
 +  tor_assert(line);
 +
 +  /* No SRV value thus don't add the line. This is possible since we might
 +   * not have a current or previous SRV value in our state. */
 +  if (srv == NULL) {
 +    return;
 +  }
 +  sr_srv_encode(encoded, sizeof(encoded), srv);
 +  tor_asprintf(&line->value, "%" PRIu64 " %s", srv->num_reveals, encoded);
 +}
 +
 +/* Reset disk state that is free allocated memory and zeroed the object. */
 +static void
 +disk_state_reset(void)
 +{
 +  /* Free allocated memory */
 +  config_free_lines(sr_disk_state->Commit);
 +  config_free_lines(sr_disk_state->SharedRandValues);
 +  config_free_lines(sr_disk_state->ExtraLines);
 +  tor_free(sr_disk_state->TorVersion);
 +
 +  /* Clean up the struct */
 +  memset(sr_disk_state, 0, sizeof(*sr_disk_state));
 +
 +  /* Reset it with useful data */
 +  sr_disk_state->magic_ = SR_DISK_STATE_MAGIC;
 +  sr_disk_state->TorVersion = tor_strdup(get_version());
 +}
 +
 +/* Update our disk state based on our global SR state. */
 +static void
 +disk_state_update(void)
 +{
 +  config_line_t **next, *line;
 +
 +  if (BUG(!sr_disk_state))
 +    return;
 +  if (BUG(!sr_state))
 +    return;
 +
 +  /* Reset current disk state. */
 +  disk_state_reset();
 +
 +  /* First, update elements that we don't need to do a construction. */
 +  sr_disk_state->Version = sr_state->version;
 +  sr_disk_state->ValidUntil = sr_state->valid_until;
 +  sr_disk_state->ValidAfter = sr_state->valid_after;
 +
 +  /* Shared random values. */
 +  next = &sr_disk_state->SharedRandValues;
 +  if (sr_state->previous_srv != NULL) {
 +    *next = line = tor_malloc_zero(sizeof(config_line_t));
 +    line->key = tor_strdup(dstate_prev_srv_key);
 +    disk_state_put_srv_line(sr_state->previous_srv, line);
 +    /* Go to the next shared random value. */
 +    next = &(line->next);
 +  }
 +  if (sr_state->current_srv != NULL) {
 +    *next = line = tor_malloc_zero(sizeof(*line));
 +    line->key = tor_strdup(dstate_cur_srv_key);
 +    disk_state_put_srv_line(sr_state->current_srv, line);
 +  }
 +
 +  /* Parse the commits and construct config line(s). */
 +  next = &sr_disk_state->Commit;
 +  DIGESTMAP_FOREACH(sr_state->commits, key, sr_commit_t *, commit) {
 +    *next = line = tor_malloc_zero(sizeof(*line));
 +    line->key = tor_strdup(dstate_commit_key);
 +    disk_state_put_commit_line(commit, line);
 +    next = &(line->next);
 +  } DIGESTMAP_FOREACH_END;
 +}
 +
 +/* Load state from disk and put it into our disk state. If the state passes
 + * validation, our global state will be updated with it. Return 0 on
 + * success. On error, -EINVAL is returned if the state on disk did contained
 + * something malformed or is unreadable. -ENOENT is returned indicating that
 + * the state file is either empty of non existing. */
 +static int
 +disk_state_load_from_disk(void)
 +{
 +  int ret;
 +  char *fname;
 +
 +  fname = get_datadir_fname(default_fname);
 +  ret = disk_state_load_from_disk_impl(fname);
 +  tor_free(fname);
 +
 +  return ret;
 +}
 +
 +/* Helper for disk_state_load_from_disk(). */
 +STATIC int
 +disk_state_load_from_disk_impl(const char *fname)
 +{
 +  int ret;
 +  char *content = NULL;
 +  sr_state_t *parsed_state = NULL;
 +  sr_disk_state_t *disk_state = NULL;
 +
 +  /* Read content of file so we can parse it. */
 +  if ((content = read_file_to_str(fname, 0, NULL)) == NULL) {
 +    log_warn(LD_FS, "SR: Unable to read SR state file %s",
 +             escaped(fname));
 +    ret = -errno;
 +    goto error;
 +  }
 +
 +  {
 +    config_line_t *lines = NULL;
 +    char *errmsg = NULL;
 +
 +    /* Every error in this code path will return EINVAL. */
 +    ret = -EINVAL;
 +    if (config_get_lines(content, &lines, 0) < 0) {
 +      config_free_lines(lines);
 +      goto error;
 +    }
 +
 +    disk_state = disk_state_new(time(NULL));
 +    config_assign(&state_format, disk_state, lines, 0, &errmsg);
 +    config_free_lines(lines);
 +    if (errmsg) {
 +      log_warn(LD_DIR, "SR: Reading state error: %s", errmsg);
 +      tor_free(errmsg);
 +      goto error;
 +    }
 +  }
 +
 +  /* So far so good, we've loaded our state file into our disk state. Let's
 +   * validate it and then parse it. */
 +  if (disk_state_validate(disk_state) < 0) {
 +    ret = -EINVAL;
 +    goto error;
 +  }
 +
 +  parsed_state = disk_state_parse(disk_state);
 +  if (parsed_state == NULL) {
 +    ret = -EINVAL;
 +    goto error;
 +  }
 +  state_set(parsed_state);
 +  disk_state_set(disk_state);
 +  tor_free(content);
 +  log_info(LD_DIR, "SR: State loaded successfully from file %s", fname);
 +  return 0;
 +
 + error:
 +  disk_state_free(disk_state);
 +  tor_free(content);
 +  return ret;
 +}
 +
 +/* Save the disk state to disk but before that update it from the current
 + * state so we always have the latest. Return 0 on success else -1. */
 +static int
 +disk_state_save_to_disk(void)
 +{
 +  int ret;
 +  char *state, *content = NULL, *fname = NULL;
 +  char tbuf[ISO_TIME_LEN + 1];
 +  time_t now = time(NULL);
 +
 +  /* If we didn't have the opportunity to setup an internal disk state,
 +   * don't bother saving something to disk. */
 +  if (sr_disk_state == NULL) {
 +    ret = 0;
 +    goto done;
 +  }
 +
 +  /* Make sure that our disk state is up to date with our memory state
 +   * before saving it to disk. */
 +  disk_state_update();
 +  state = config_dump(&state_format, NULL, sr_disk_state, 0, 0);
 +  format_local_iso_time(tbuf, now);
 +  tor_asprintf(&content,
 +               "# Tor shared random state file last generated on %s "
 +               "local time\n"
 +               "# Other times below are in UTC\n"
 +               "# Please *do not* edit this file.\n\n%s",
 +               tbuf, state);
 +  tor_free(state);
 +  fname = get_datadir_fname(default_fname);
 +  if (write_str_to_file(fname, content, 0) < 0) {
 +    log_warn(LD_FS, "SR: Unable to write SR state to file %s", fname);
 +    ret = -1;
 +    goto done;
 +  }
 +  ret = 0;
 +  log_debug(LD_DIR, "SR: Saved state to file %s", fname);
 +
 + done:
 +  tor_free(fname);
 +  tor_free(content);
 +  return ret;
 +}
 +
 +/* Reset our state to prepare for a new protocol run. Once this returns, all
 + * commits in the state will be removed and freed. */
 +STATIC void
 +reset_state_for_new_protocol_run(time_t valid_after)
 +{
 +  if (BUG(!sr_state))
 +    return;
 +
 +  /* Keep counters in track */
 +  sr_state->n_reveal_rounds = 0;
 +  sr_state->n_commit_rounds = 0;
 +  sr_state->n_protocol_runs++;
 +
 +  /* Reset valid-until */
 +  sr_state->valid_until = get_state_valid_until_time(valid_after);
 +  sr_state->valid_after = valid_after;
 +
 +  /* We are in a new protocol run so cleanup commits. */
 +  sr_state_delete_commits();
 +}
 +
 +/* This is the first round of the new protocol run starting at
 + * <b>valid_after</b>. Do the necessary housekeeping. */
 +STATIC void
 +new_protocol_run(time_t valid_after)
 +{
 +  sr_commit_t *our_commitment = NULL;
 +
 +  /* Only compute the srv at the end of the reveal phase. */
 +  if (sr_state->phase == SR_PHASE_REVEAL) {
 +    /* We are about to compute a new shared random value that will be set in
 +     * our state as the current value so rotate values. */
 +    state_rotate_srv();
 +    /* Compute the shared randomness value of the day. */
 +    sr_compute_srv();
 +  }
 +
 +  /* Prepare for the new protocol run by reseting the state */
 +  reset_state_for_new_protocol_run(valid_after);
 +
 +  /* Do some logging */
 +  log_info(LD_DIR, "SR: Protocol run #%" PRIu64 " starting!",
 +           sr_state->n_protocol_runs);
 +
 +  /* Generate fresh commitments for this protocol run */
 +  our_commitment = sr_generate_our_commit(valid_after,
 +                                          get_my_v3_authority_cert());
 +  if (our_commitment) {
 +    /* Add our commitment to our state. In case we are unable to create one
 +     * (highly unlikely), we won't vote for this protocol run since our
 +     * commitment won't be in our state. */
 +    sr_state_add_commit(our_commitment);
 +  }
 +}
 +
 +/* Return 1 iff the <b>next_phase</b> is a phase transition from the current
 + * phase that is it's different. */
 +STATIC int
 +is_phase_transition(sr_phase_t next_phase)
 +{
 +  return sr_state->phase != next_phase;
 +}
 +
 +/* Helper function: return a commit using the RSA fingerprint of the
 + * authority or NULL if no such commit is known. */
 +static sr_commit_t *
 +state_query_get_commit(const char *rsa_fpr)
 +{
 +  tor_assert(rsa_fpr);
 +  return digestmap_get(sr_state->commits, rsa_fpr);
 +}
 +
 +/* Helper function: This handles the GET state action using an
 + * <b>obj_type</b> and <b>data</b> needed for the action. */
 +static void *
 +state_query_get_(sr_state_object_t obj_type, const void *data)
 +{
 +  void *obj = NULL;
 +
 +  switch (obj_type) {
 +  case SR_STATE_OBJ_COMMIT:
 +  {
 +    obj = state_query_get_commit(data);
 +    break;
 +  }
 +  case SR_STATE_OBJ_COMMITS:
 +    obj = sr_state->commits;
 +    break;
 +  case SR_STATE_OBJ_CURSRV:
 +    obj = sr_state->current_srv;
 +    break;
 +  case SR_STATE_OBJ_PREVSRV:
 +    obj = sr_state->previous_srv;
 +    break;
 +  case SR_STATE_OBJ_PHASE:
 +    obj = &sr_state->phase;
 +    break;
 +  case SR_STATE_OBJ_VALID_AFTER:
 +  default:
 +    tor_assert(0);
 +  }
 +  return obj;
 +}
 +
 +/* Helper function: This handles the PUT state action using an
 + * <b>obj_type</b> and <b>data</b> needed for the action. */
 +static void
 +state_query_put_(sr_state_object_t obj_type, void *data)
 +{
 +  switch (obj_type) {
 +  case SR_STATE_OBJ_COMMIT:
 +  {
 +    sr_commit_t *commit = data;
 +    tor_assert(commit);
 +    commit_add_to_state(commit, sr_state);
 +    break;
 +  }
 +  case SR_STATE_OBJ_CURSRV:
 +    sr_state->current_srv = (sr_srv_t *) data;
 +    break;
 +  case SR_STATE_OBJ_PREVSRV:
 +    sr_state->previous_srv = (sr_srv_t *) data;
 +    break;
 +  case SR_STATE_OBJ_VALID_AFTER:
 +    sr_state->valid_after = *((time_t *) data);
 +    break;
 +  /* It's not allowed to change the phase nor the full commitments map from
 +   * the state. The phase is decided during a strict process post voting and
 +   * the commits should be put individually. */
 +  case SR_STATE_OBJ_PHASE:
 +  case SR_STATE_OBJ_COMMITS:
 +  default:
 +    tor_assert(0);
 +  }
 +}
 +
 +/* Helper function: This handles the DEL_ALL state action using an
 + * <b>obj_type</b> and <b>data</b> needed for the action. */
 +static void
 +state_query_del_all_(sr_state_object_t obj_type)
 +{
 +  switch (obj_type) {
 +  case SR_STATE_OBJ_COMMIT:
 +  {
 +    /* We are in a new protocol run so cleanup commitments. */
 +    DIGESTMAP_FOREACH_MODIFY(sr_state->commits, key, sr_commit_t *, c) {
 +      sr_commit_free(c);
 +      MAP_DEL_CURRENT(key);
 +    } DIGESTMAP_FOREACH_END;
 +    break;
 +  }
 +  /* The following object are _NOT_ suppose to be removed. */
 +  case SR_STATE_OBJ_CURSRV:
 +  case SR_STATE_OBJ_PREVSRV:
 +  case SR_STATE_OBJ_PHASE:
 +  case SR_STATE_OBJ_COMMITS:
 +  case SR_STATE_OBJ_VALID_AFTER:
 +  default:
 +    tor_assert(0);
 +  }
 +}
 +
 +/* Helper function: This handles the DEL state action using an
 + * <b>obj_type</b> and <b>data</b> needed for the action. */
 +static void
 +state_query_del_(sr_state_object_t obj_type, void *data)
 +{
 +  (void) data;
 +
 +  switch (obj_type) {
 +  case SR_STATE_OBJ_PREVSRV:
 +    tor_free(sr_state->previous_srv);
 +    break;
 +  case SR_STATE_OBJ_CURSRV:
 +    tor_free(sr_state->current_srv);
 +    break;
 +  case SR_STATE_OBJ_COMMIT:
 +  case SR_STATE_OBJ_COMMITS:
 +  case SR_STATE_OBJ_PHASE:
 +  case SR_STATE_OBJ_VALID_AFTER:
 +  default:
 +    tor_assert(0);
 +  }
 +}
 +
 +/* Query state using an <b>action</b> for an object type <b>obj_type</b>.
 + * The <b>data</b> pointer needs to point to an object that the action needs
 + * to use and if anything is required to be returned, it is stored in
 + * <b>out</b>.
 + *
 + * This mechanism exists so we have one single point where we synchronized
 + * our memory state with our disk state for every actions that changes it.
 + * We then trigger a write on disk immediately.
 + *
 + * This should be the only entry point to our memory state. It's used by all
 + * our state accessors and should be in the future. */
 +static void
 +state_query(sr_state_action_t action, sr_state_object_t obj_type,
 +            void *data, void **out)
 +{
 +  switch (action) {
 +  case SR_STATE_ACTION_GET:
 +    *out = state_query_get_(obj_type, data);
 +    break;
 +  case SR_STATE_ACTION_PUT:
 +    state_query_put_(obj_type, data);
 +    break;
 +  case SR_STATE_ACTION_DEL:
 +    state_query_del_(obj_type, data);
 +    break;
 +  case SR_STATE_ACTION_DEL_ALL:
 +    state_query_del_all_(obj_type);
 +    break;
 +  case SR_STATE_ACTION_SAVE:
 +    /* Only trigger a disk state save. */
 +    break;
 +  default:
 +    tor_assert(0);
 +  }
 +
 +  /* If the action actually changes the state, immediately save it to disk.
 +   * The following will sync the state -> disk state and then save it. */
 +  if (action != SR_STATE_ACTION_GET) {
 +    disk_state_save_to_disk();
 +  }
 +}
 +
 +/* Delete the current SRV value from the state freeing it and the value is set
 + * to NULL meaning empty. */
- static void
++STATIC void
 +state_del_current_srv(void)
 +{
 +  state_query(SR_STATE_ACTION_DEL, SR_STATE_OBJ_CURSRV, NULL, NULL);
 +}
 +
 +/* Delete the previous SRV value from the state freeing it and the value is
 + * set to NULL meaning empty. */
- static void
++STATIC void
 +state_del_previous_srv(void)
 +{
 +  state_query(SR_STATE_ACTION_DEL, SR_STATE_OBJ_PREVSRV, NULL, NULL);
 +}
 +
 +/* Rotate SRV value by freeing the previous value, assigning the current
 + * value to the previous one and nullifying the current one. */
 +STATIC void
 +state_rotate_srv(void)
 +{
 +  /* First delete previous SRV from the state. Object will be freed. */
 +  state_del_previous_srv();
 +  /* Set previous SRV with the current one. */
 +  sr_state_set_previous_srv(sr_state_get_current_srv());
 +  /* Nullify the current srv. */
 +  sr_state_set_current_srv(NULL);
 +}
 +
 +/* Set valid after time in the our state. */
 +void
 +sr_state_set_valid_after(time_t valid_after)
 +{
 +  state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_VALID_AFTER,
 +              (void *) &valid_after, NULL);
 +}
 +
 +/* Return the phase we are currently in according to our state. */
 +sr_phase_t
 +sr_state_get_phase(void)
 +{
 +  void *ptr;
 +  state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_PHASE, NULL, &ptr);
 +  return *(sr_phase_t *) ptr;
 +}
 +
 +/* Return the previous SRV value from our state. Value CAN be NULL. */
 +const sr_srv_t *
 +sr_state_get_previous_srv(void)
 +{
 +  const sr_srv_t *srv;
 +  state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_PREVSRV, NULL,
 +              (void *) &srv);
 +  return srv;
 +}
 +
 +/* Set the current SRV value from our state. Value CAN be NULL. The srv
 + * object ownership is transferred to the state object. */
 +void
 +sr_state_set_previous_srv(const sr_srv_t *srv)
 +{
 +  state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_PREVSRV, (void *) srv,
 +              NULL);
 +}
 +
 +/* Return the current SRV value from our state. Value CAN be NULL. */
 +const sr_srv_t *
 +sr_state_get_current_srv(void)
 +{
 +  const sr_srv_t *srv;
 +  state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_CURSRV, NULL,
 +              (void *) &srv);
 +  return srv;
 +}
 +
 +/* Set the current SRV value from our state. Value CAN be NULL. The srv
 + * object ownership is transferred to the state object. */
 +void
 +sr_state_set_current_srv(const sr_srv_t *srv)
 +{
 +  state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_CURSRV, (void *) srv,
 +              NULL);
 +}
 +
 +/* Clean all the SRVs in our state. */
 +void
 +sr_state_clean_srvs(void)
 +{
 +  /* Remove SRVs from state. They will be set to NULL as "empty". */
 +  state_del_previous_srv();
 +  state_del_current_srv();
 +}
 +
 +/* Return a pointer to the commits map from our state. CANNOT be NULL. */
 +digestmap_t *
 +sr_state_get_commits(void)
 +{
 +  digestmap_t *commits;
 +  state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_COMMITS,
 +              NULL, (void *) &commits);
 +  tor_assert(commits);
 +  return commits;
 +}
 +
 +/* Update the current SR state as needed for the upcoming voting round at
 + * <b>valid_after</b>. */
 +void
 +sr_state_update(time_t valid_after)
 +{
 +  sr_phase_t next_phase;
 +
 +  if (BUG(!sr_state))
 +    return;
 +
 +  /* Don't call this function twice in the same voting period. */
 +  if (valid_after <= sr_state->valid_after) {
 +    log_info(LD_DIR, "SR: Asked to update state twice. Ignoring.");
 +    return;
 +  }
 +
 +  /* Get phase of upcoming round. */
 +  next_phase = get_sr_protocol_phase(valid_after);
 +
 +  /* If we are transitioning to a new protocol phase, prepare the stage. */
 +  if (is_phase_transition(next_phase)) {
 +    if (next_phase == SR_PHASE_COMMIT) {
 +      /* Going into commit phase means we are starting a new protocol run. */
 +      new_protocol_run(valid_after);
 +    }
 +    /* Set the new phase for this round */
 +    sr_state->phase = next_phase;
 +  } else if (sr_state->phase == SR_PHASE_COMMIT &&
 +             digestmap_size(sr_state->commits) == 0) {
 +    /* We are _NOT_ in a transition phase so if we are in the commit phase
 +     * and have no commit, generate one. Chances are that we are booting up
 +     * so let's have a commit in our state for the next voting period. */
 +    sr_commit_t *our_commit =
 +      sr_generate_our_commit(valid_after, get_my_v3_authority_cert());
 +    if (our_commit) {
 +      /* Add our commitment to our state. In case we are unable to create one
 +       * (highly unlikely), we won't vote for this protocol run since our
 +       * commitment won't be in our state. */
 +      sr_state_add_commit(our_commit);
 +    }
 +  }
 +
 +  sr_state_set_valid_after(valid_after);
 +
 +  /* Count the current round */
 +  if (sr_state->phase == SR_PHASE_COMMIT) {
 +    /* invariant check: we've not entered reveal phase yet */
 +    if (BUG(sr_state->n_reveal_rounds != 0))
 +      return;
 +    sr_state->n_commit_rounds++;
 +  } else {
 +    sr_state->n_reveal_rounds++;
 +  }
 +
 +  { /* Debugging. */
 +    char tbuf[ISO_TIME_LEN + 1];
 +    format_iso_time(tbuf, valid_after);
 +    log_info(LD_DIR, "SR: State prepared for upcoming voting period (%s). "
 +             "Upcoming phase is %s (counters: %d commit & %d reveal rounds).",
 +             tbuf, get_phase_str(sr_state->phase),
 +             sr_state->n_commit_rounds, sr_state->n_reveal_rounds);
 +  }
 +}
 +
 +/* Return commit object from the given authority digest <b>rsa_identity</b>.
 + * Return NULL if not found. */
 +sr_commit_t *
 +sr_state_get_commit(const char *rsa_identity)
 +{
 +  sr_commit_t *commit;
 +
 +  tor_assert(rsa_identity);
 +
 +  state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_COMMIT,
 +              (void *) rsa_identity, (void *) &commit);
 +  return commit;
 +}
 +
 +/* Add <b>commit</b> to the permanent state. The commit object ownership is
 + * transferred to the state so the caller MUST not free it. */
 +void
 +sr_state_add_commit(sr_commit_t *commit)
 +{
 +  tor_assert(commit);
 +
 +  /* Put the commit to the global state. */
 +  state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_COMMIT,
 +              (void *) commit, NULL);
 +
 +  log_debug(LD_DIR, "SR: Commit from %s has been added to our state.",
 +            sr_commit_get_rsa_fpr(commit));
 +}
 +
 +/* Remove all commits from our state. */
 +void
 +sr_state_delete_commits(void)
 +{
 +  state_query(SR_STATE_ACTION_DEL_ALL, SR_STATE_OBJ_COMMIT, NULL, NULL);
 +}
 +
 +/* Copy the reveal information from <b>commit</b> into <b>saved_commit</b>.
 + * This <b>saved_commit</b> MUST come from our current SR state. Once modified,
 + * the disk state is updated. */
 +void
 +sr_state_copy_reveal_info(sr_commit_t *saved_commit, const sr_commit_t *commit)
 +{
 +  tor_assert(saved_commit);
 +  tor_assert(commit);
 +
 +  saved_commit->reveal_ts = commit->reveal_ts;
 +  memcpy(saved_commit->random_number, commit->random_number,
 +         sizeof(saved_commit->random_number));
 +
 +  strlcpy(saved_commit->encoded_reveal, commit->encoded_reveal,
 +          sizeof(saved_commit->encoded_reveal));
 +  state_query(SR_STATE_ACTION_SAVE, 0, NULL, NULL);
 +  log_debug(LD_DIR, "SR: Reveal value learned %s (for commit %s) from %s",
 +            saved_commit->encoded_reveal, saved_commit->encoded_commit,
 +            sr_commit_get_rsa_fpr(saved_commit));
 +}
 +
 +/* Set the fresh SRV flag from our state. This doesn't need to trigger a
 + * disk state synchronization so we directly change the state. */
 +void
 +sr_state_set_fresh_srv(void)
 +{
 +  sr_state->is_srv_fresh = 1;
 +}
 +
 +/* Unset the fresh SRV flag from our state. This doesn't need to trigger a
 + * disk state synchronization so we directly change the state. */
 +void
 +sr_state_unset_fresh_srv(void)
 +{
 +  sr_state->is_srv_fresh = 0;
 +}
 +
 +/* Return the value of the fresh SRV flag. */
 +unsigned int
 +sr_state_srv_is_fresh(void)
 +{
 +  return sr_state->is_srv_fresh;
 +}
 +
 +/* Cleanup and free our disk and memory state. */
 +void
 +sr_state_free_all(void)
 +{
 +  state_free(sr_state);
 +  disk_state_free(sr_disk_state);
 +  /* Nullify our global state. */
 +  sr_state = NULL;
 +  sr_disk_state = NULL;
 +}
 +
 +/* Save our current state in memory to disk. */
 +void
 +sr_state_save(void)
 +{
 +  /* Query a SAVE action on our current state so it's synced and saved. */
 +  state_query(SR_STATE_ACTION_SAVE, 0, NULL, NULL);
 +}
 +
 +/* Return 1 iff the state has been initialized that is it exists in memory.
 + * Return 0 otherwise. */
 +int
 +sr_state_is_initialized(void)
 +{
 +  return sr_state == NULL ? 0 : 1;
 +}
 +
 +/* Initialize the disk and memory state.
 + *
 + * If save_to_disk is set to 1, the state is immediately saved to disk after
 + * creation else it's not thus only kept in memory.
 + * If read_from_disk is set to 1, we try to load the state from the disk and
 + * if not found, a new state is created.
 + *
 + * Return 0 on success else a negative value on error. */
 +int
 +sr_state_init(int save_to_disk, int read_from_disk)
 +{
 +  int ret = -ENOENT;
 +  time_t now = time(NULL);
 +
 +  /* We shouldn't have those assigned. */
 +  tor_assert(sr_disk_state == NULL);
 +  tor_assert(sr_state == NULL);
 +
 +  /* First, try to load the state from disk. */
 +  if (read_from_disk) {
 +    ret = disk_state_load_from_disk();
 +  }
 +
 +  if (ret < 0) {
 +    switch (-ret) {
 +    case EINVAL:
 +      /* We have a state on disk but it contains something we couldn't parse
 +       * or an invalid entry in the state file. Let's remove it since it's
 +       * obviously unusable and replace it by an new fresh state below. */
 +    case ENOENT:
 +      {
 +        /* No state on disk so allocate our states for the first time. */
 +        sr_state_t *new_state = state_new(default_fname, now);
 +        sr_disk_state_t *new_disk_state = disk_state_new(now);
 +        state_set(new_state);
 +        /* It's important to set our disk state pointer since the save call
 +         * below uses it to synchronized it with our memory state.  */
 +        disk_state_set(new_disk_state);
 +        /* No entry, let's save our new state to disk. */
 +        if (save_to_disk && disk_state_save_to_disk() < 0) {
 +          goto error;
 +        }
 +        break;
 +      }
 +    default:
 +      /* Big problem. Not possible. */
 +      tor_assert(0);
 +    }
 +  }
 +  /* We have a state in memory, let's make sure it's updated for the current
 +   * and next voting round. */
 +  {
 +    time_t valid_after = voting_schedule_get_next_valid_after_time();
 +    sr_state_update(valid_after);
 +  }
 +  return 0;
 +
 + error:
 +  return -1;
 +}
 +
 +#ifdef TOR_UNIT_TESTS
 +
 +/* Set the current phase of the protocol. Used only by unit tests. */
 +void
 +set_sr_phase(sr_phase_t phase)
 +{
 +  if (BUG(!sr_state))
 +    return;
 +  sr_state->phase = phase;
 +}
 +
 +/* Get the SR state. Used only by unit tests */
 +sr_state_t *
 +get_sr_state(void)
 +{
 +  return sr_state;
 +}
 +
 +#endif /* defined(TOR_UNIT_TESTS) */
diff --cc src/feature/dirauth/shared_random_state.h
index 35626be3f,000000000..08f999f9d
mode 100644,000000..100644
--- a/src/feature/dirauth/shared_random_state.h
+++ b/src/feature/dirauth/shared_random_state.h
@@@ -1,146 -1,0 +1,148 @@@
 +/* Copyright (c) 2016-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +#ifndef TOR_SHARED_RANDOM_STATE_H
 +#define TOR_SHARED_RANDOM_STATE_H
 +
 +#include "feature/dirauth/shared_random.h"
 +
 +/* Action that can be performed on the state for any objects. */
 +typedef enum {
 +  SR_STATE_ACTION_GET     = 1,
 +  SR_STATE_ACTION_PUT     = 2,
 +  SR_STATE_ACTION_DEL     = 3,
 +  SR_STATE_ACTION_DEL_ALL = 4,
 +  SR_STATE_ACTION_SAVE    = 5,
 +} sr_state_action_t;
 +
 +/* Object in the state that can be queried through the state API. */
 +typedef enum {
 +  /* Will return a single commit using an authority identity key. */
 +  SR_STATE_OBJ_COMMIT,
 +  /* Returns the entire list of commits from the state. */
 +  SR_STATE_OBJ_COMMITS,
 +  /* Return the current SRV object pointer. */
 +  SR_STATE_OBJ_CURSRV,
 +  /* Return the previous SRV object pointer. */
 +  SR_STATE_OBJ_PREVSRV,
 +  /* Return the phase. */
 +  SR_STATE_OBJ_PHASE,
 +  /* Get or Put the valid after time. */
 +  SR_STATE_OBJ_VALID_AFTER,
 +} sr_state_object_t;
 +
 +/* State of the protocol. It's also saved on disk in fname. This data
 + * structure MUST be synchronized at all time with the one on disk. */
 +typedef struct sr_state_t {
 +  /* Filename of the state file on disk. */
 +  char *fname;
 +  /* Version of the protocol. */
 +  uint32_t version;
 +  /* The valid-after of the voting period we have prepared the state for. */
 +  time_t valid_after;
 +  /* Until when is this state valid? */
 +  time_t valid_until;
 +  /* Protocol phase. */
 +  sr_phase_t phase;
 +
 +  /* Number of runs completed. */
 +  uint64_t n_protocol_runs;
 +  /* The number of commitment rounds we've performed in this protocol run. */
 +  unsigned int n_commit_rounds;
 +  /* The number of reveal rounds we've performed in this protocol run. */
 +  unsigned int n_reveal_rounds;
 +
 +  /* A map of all the received commitments for this protocol run. This is
 +   * indexed by authority RSA identity digest. */
 +  digestmap_t *commits;
 +
 +  /* Current and previous shared random value. */
 +  sr_srv_t *previous_srv;
 +  sr_srv_t *current_srv;
 +
 +  /* Indicate if the state contains an SRV that was _just_ generated. This is
 +   * used during voting so that we know whether to use the super majority rule
 +   * or not when deciding on keeping it for the consensus. It is _always_ set
 +   * to 0 post consensus.
 +   *
 +   * EDGE CASE: if an authority computes a new SRV then immediately reboots
 +   * and, once back up, votes for the current round, it won't know if the
 +   * SRV is fresh or not ultimately making it _NOT_ use the super majority
 +   * when deciding to put or not the SRV in the consensus. This is for now
 +   * an acceptable very rare edge case. */
 +  unsigned int is_srv_fresh:1;
 +} sr_state_t;
 +
 +/* Persistent state of the protocol, as saved to disk. */
 +typedef struct sr_disk_state_t {
 +  uint32_t magic_;
 +  /* Version of the protocol. */
 +  int Version;
 +  /* Version of our running tor. */
 +  char *TorVersion;
 +  /* Creation time of this state */
 +  time_t ValidAfter;
 +  /* State valid until? */
 +  time_t ValidUntil;
 +  /* All commits seen that are valid. */
 +  struct config_line_t *Commit;
 +  /* Previous and current shared random value. */
 +  struct config_line_t *SharedRandValues;
 +  /* Extra Lines for configuration we might not know. */
 +  struct config_line_t *ExtraLines;
 +} sr_disk_state_t;
 +
 +/* API */
 +
 +/* Public methods: */
 +
 +void sr_state_update(time_t valid_after);
 +
 +/* Private methods (only used by shared-random.c): */
 +
 +void sr_state_set_valid_after(time_t valid_after);
 +sr_phase_t sr_state_get_phase(void);
 +const sr_srv_t *sr_state_get_previous_srv(void);
 +const sr_srv_t *sr_state_get_current_srv(void);
 +void sr_state_set_previous_srv(const sr_srv_t *srv);
 +void sr_state_set_current_srv(const sr_srv_t *srv);
 +void sr_state_clean_srvs(void);
 +digestmap_t *sr_state_get_commits(void);
 +sr_commit_t *sr_state_get_commit(const char *rsa_fpr);
 +void sr_state_add_commit(sr_commit_t *commit);
 +void sr_state_delete_commits(void);
 +void sr_state_copy_reveal_info(sr_commit_t *saved_commit,
 +                               const sr_commit_t *commit);
 +unsigned int sr_state_srv_is_fresh(void);
 +void sr_state_set_fresh_srv(void);
 +void sr_state_unset_fresh_srv(void);
 +int sr_state_init(int save_to_disk, int read_from_disk);
 +int sr_state_is_initialized(void);
 +void sr_state_save(void);
 +void sr_state_free_all(void);
 +
 +#ifdef SHARED_RANDOM_STATE_PRIVATE
 +
 +STATIC int disk_state_load_from_disk_impl(const char *fname);
 +
 +STATIC sr_phase_t get_sr_protocol_phase(time_t valid_after);
 +
 +STATIC time_t get_state_valid_until_time(time_t now);
 +STATIC const char *get_phase_str(sr_phase_t phase);
 +STATIC void reset_state_for_new_protocol_run(time_t valid_after);
 +STATIC void new_protocol_run(time_t valid_after);
 +STATIC void state_rotate_srv(void);
 +STATIC int is_phase_transition(sr_phase_t next_phase);
 +
 +#endif /* defined(SHARED_RANDOM_STATE_PRIVATE) */
 +
 +#ifdef TOR_UNIT_TESTS
 +
 +STATIC void set_sr_phase(sr_phase_t phase);
 +STATIC sr_state_t *get_sr_state(void);
++STATIC void state_del_previous_srv(void);
++STATIC void state_del_current_srv(void);
 +
 +#endif /* defined(TOR_UNIT_TESTS) */
 +
 +#endif /* !defined(TOR_SHARED_RANDOM_STATE_H) */



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