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//! consensus documents - items that vary by consensus flavor
//!
//! **This file is reincluded multiple times**,
//! by the macros in [`crate::doc::ns_variety_definition_macros`],
//! once for votes, and once for each consensus flavour.
//! It is *not* a module `crate::doc::netstatus::rs::each_flavor`.
//! Each time this file is included by one of the macros mentioned above,
//! the `ns_***` macros (such as `ns_const_name!`) may expand to different values.
//! See [`crate::doc::ns_variety_definition_macros`].
use super::*;
ns_use_this_variety! {
use [crate::doc::netstatus::rs]::?::{RouterStatus};
}
#[cfg(feature = "build_docs")]
pub(crate) use [crate::doc::netstatus::build]::?::{ConsensusBuilder};
pub use [crate::doc::netstatus::rs::build]::?::{RouterStatusBuilder};
/// A single consensus netstatus, as produced by the old parser.
#[derive(Debug, Clone)]
#[non_exhaustive]
pub struct Consensus {
/// What kind of consensus document is this? Absent in votes and
/// in ns-flavored consensuses.
pub flavor: ConsensusFlavor,
/// The preamble, except for the intro item.
pub preamble: Preamble,
/// List of voters whose votes contributed to this consensus.
pub voters: Vec<ConsensusVoterInfo>,
/// A list of routerstatus entries for the relays on the network,
/// with one entry per relay.
///
/// These are currently ordered by the router's RSA identity, but this is not
/// to be relied on, since we may want to even abolish RSA at some point!
pub relays: Vec<RouterStatus>,
/// Footer for the consensus object.
pub footer: Footer,
impl Consensus {
/// Return the Lifetime for this consensus.
pub fn lifetime(&self) -> &Lifetime {
&self.preamble.lifetime
/// Return a slice of all the routerstatus entries in this consensus.
pub fn relays(&self) -> &[RouterStatus] {
&self.relays[..]
/// Return a mapping from keywords to integers representing how
/// to weight different kinds of relays in different path positions.
pub fn bandwidth_weights(&self) -> &NetParams<i32> {
&self.footer.weights
/// Return the map of network parameters that this consensus advertises.
pub fn params(&self) -> &NetParams<i32> {
&self.preamble.params
/// Return the latest shared random value, if the consensus
/// contains one.
pub fn shared_rand_cur(&self) -> Option<&SharedRandStatus> {
self.preamble.shared_rand_current_value.as_ref()
/// Return the previous shared random value, if the consensus
pub fn shared_rand_prev(&self) -> Option<&SharedRandStatus> {
self.preamble.shared_rand_previous_value.as_ref()
/// Return a [`ProtoStatus`] that lists the network's current requirements and
/// recommendations for the list of protocols that every relay must implement.
pub fn relay_protocol_status(&self) -> &ProtoStatus {
&self.preamble.proto_statuses.relay
/// recommendations for the list of protocols that every client must implement.
pub fn client_protocol_status(&self) -> &ProtoStatus {
&self.preamble.proto_statuses.client
/// Return a set of all known [`ProtoStatus`] values.
pub fn protocol_statuses(&self) -> &Arc<ProtoStatuses> {
&self.preamble.proto_statuses
/// Return a new ConsensusBuilder for building test consensus objects.
/// This function is only available when the `build_docs` feature has
/// been enabled.
pub fn builder() -> ConsensusBuilder {
ConsensusBuilder::new(RouterStatus::flavor())
/// Try to parse a single networkstatus document from a string.
pub fn parse(s: &str) -> Result<(&str, &str, UncheckedConsensus)> {
let mut reader = NetDocReader::new(s)?;
Self::parse_from_reader(&mut reader).map_err(|e| e.within(s))
/// Extract a voter-info section from the reader; return
/// Ok(None) when we are out of voter-info sections.
fn take_voterinfo(
r: &mut NetDocReader<'_, NetstatusKwd>,
) -> Result<Option<ConsensusVoterInfo>> {
use NetstatusKwd::*;
match r.peek() {
None => return Ok(None),
Some(e) if e.is_ok_with_kwd_in(&[RS_R, DIRECTORY_FOOTER]) => return Ok(None),
_ => (),
};
let mut first_dir_source = true;
// TODO: Extract this pattern into a "pause at second"???
// Pause at the first 'r', or the second 'dir-source'.
let mut p = r.pause_at(|i| match i {
Err(_) => false,
Ok(item) => {
item.kwd() == RS_R
|| if item.kwd() == DIR_SOURCE {
let was_first = first_dir_source;
first_dir_source = false;
!was_first
} else {
false
});
let voter_sec = NS_VOTERINFO_RULES_CONSENSUS.parse(&mut p)?;
let voter = ConsensusVoterInfo::from_section(&voter_sec)?;
Ok(Some(voter))
/// Extract the footer (but not signatures) from the reader.
fn take_footer(r: &mut NetDocReader<'_, NetstatusKwd>) -> Result<Footer> {
let mut p = r.pause_at(|i| i.is_ok_with_kwd_in(&[DIRECTORY_SIGNATURE]));
let footer_sec = NS_FOOTER_RULES.parse(&mut p)?;
let footer = Footer::from_section(&footer_sec)?;
Ok(footer)
/// Extract a routerstatus from the reader. Return Ok(None) if we're
/// out of routerstatus entries.
fn take_routerstatus(r: &mut NetDocReader<'_, NetstatusKwd>) -> Result<Option<(Pos, RouterStatus)>> {
Some(e) if e.is_ok_with_kwd_in(&[DIRECTORY_FOOTER]) => return Ok(None),
let pos = r.pos();
let mut first_r = true;
item.kwd() == DIRECTORY_FOOTER
|| if item.kwd() == RS_R {
let was_first = first_r;
first_r = false;
let rules = match RouterStatus::flavor() {
ConsensusFlavor::Microdesc => &NS_ROUTERSTATUS_RULES_MDCON,
ConsensusFlavor::Plain => &NS_ROUTERSTATUS_RULES_PLAIN,
let rs_sec = rules.parse(&mut p)?;
let rs = RouterStatus::from_section(&rs_sec)?;
Ok(Some((pos, rs)))
/// Extract an entire UncheckedConsensus from a reader.
/// Returns the signed portion of the string, the remainder of the
/// string, and an UncheckedConsensus.
fn parse_from_reader<'a>(
r: &mut NetDocReader<'a, NetstatusKwd>,
) -> Result<(&'a str, &'a str, UncheckedConsensus)> {
let ((flavor, preamble), start_pos) = {
let mut h = r.pause_at(|i| i.is_ok_with_kwd_in(&[DIR_SOURCE]));
let preamble_sec = NS_HEADER_RULES_CONSENSUS.parse(&mut h)?;
// Unwrapping should be safe because above `.parse` would have
// returned an Error
#[allow(clippy::unwrap_used)]
let pos = preamble_sec.first_item().unwrap().offset_in(r.str()).unwrap();
(Preamble::from_section(&preamble_sec)?, pos)
if RouterStatus::flavor() != flavor {
return Err(EK::BadDocumentType.with_msg(format!(
"Expected {:?}, got {:?}",
RouterStatus::flavor(),
flavor
)));
let mut voters = Vec::new();
while let Some(voter) = Self::take_voterinfo(r)? {
voters.push(voter);
let mut relays: Vec<RouterStatus> = Vec::new();
while let Some((pos, routerstatus)) = Self::take_routerstatus(r)? {
if let Some(prev) = relays.last() {
if prev.rsa_identity() >= routerstatus.rsa_identity() {
return Err(EK::WrongSortOrder.at_pos(pos));
relays.push(routerstatus);
relays.shrink_to_fit();
let footer = Self::take_footer(r)?;
let consensus = Consensus {
flavor,
preamble,
voters,
relays,
footer,
// Find the signatures.
let mut first_sig: Option<Item<'_, NetstatusKwd>> = None;
let mut signatures = Vec::new();
for item in &mut *r {
let item = item?;
if item.kwd() != DIRECTORY_SIGNATURE {
return Err(EK::UnexpectedToken
.with_msg(item.kwd().to_str())
.at_pos(item.pos()));
let sig = Signature::from_item(&item)?;
if first_sig.is_none() {
first_sig = Some(item);
signatures.push(sig);
let end_pos = match first_sig {
None => return Err(EK::MissingToken.with_msg("directory-signature")),
// Unwrap should be safe because `first_sig` was parsed from `r`
Some(sig) => sig.offset_in(r.str()).unwrap() + "directory-signature ".len(),
// Find the appropriate digest.
let signed_str = &r.str()[start_pos..end_pos];
let remainder = &r.str()[end_pos..];
let (sha256, sha1) = match RouterStatus::flavor() {
ConsensusFlavor::Plain => (
None,
Some(ll::d::Sha1::digest(signed_str.as_bytes()).into()),
),
ConsensusFlavor::Microdesc => (
Some(ll::d::Sha256::digest(signed_str.as_bytes()).into()),
let siggroup = SignatureGroup {
sha256,
sha1,
signatures,
let unval = UnvalidatedConsensus {
consensus,
siggroup,
n_authorities: None,
let lifetime = unval.consensus.preamble.lifetime.clone();
let delay = unval.consensus.preamble.voting_delay.unwrap_or((0, 0));
let dist_interval = time::Duration::from_secs(delay.1.into());
let starting_time = *lifetime.valid_after - dist_interval;
let timebound = TimerangeBound::new(unval, starting_time..*lifetime.valid_until);
Ok((signed_str, remainder, timebound))
impl Preamble {
/// Extract the CommonPreamble members from a single preamble section.
fn from_section(sec: &Section<'_, NetstatusKwd>) -> Result<(ConsensusFlavor, Preamble)> {
{
// this unwrap is safe because if there is not at least one
// token in the section, the section is unparsable.
let first = sec.first_item().unwrap();
if first.kwd() != NETWORK_STATUS_VERSION {
.with_msg(first.kwd().to_str())
.at_pos(first.pos()));
let ver_item = sec.required(NETWORK_STATUS_VERSION)?;
let version: u32 = ver_item.parse_arg(0)?;
if version != 3 {
return Err(EK::BadDocumentVersion.with_msg(version.to_string()));
let flavor = ConsensusFlavor::from_opt_name(ver_item.arg(1))?;
let valid_after = sec
.required(VALID_AFTER)?
.args_as_str()
.parse::<Iso8601TimeSp>()?
.into();
let fresh_until = sec
.required(FRESH_UNTIL)?
let valid_until = sec
.required(VALID_UNTIL)?
let lifetime = Lifetime::new(valid_after, fresh_until, valid_until)?;
let client_versions = sec
.maybe(CLIENT_VERSIONS)
.unwrap_or("")
.split(',')
.map(str::to_string)
.collect();
let server_versions = sec
.maybe(SERVER_VERSIONS)
let proto_statuses = {
let client = ProtoStatus::from_section(
sec,
RECOMMENDED_CLIENT_PROTOCOLS,
REQUIRED_CLIENT_PROTOCOLS,
)?;
let relay = ProtoStatus::from_section(
RECOMMENDED_RELAY_PROTOCOLS,
REQUIRED_RELAY_PROTOCOLS,
Arc::new(ProtoStatuses { client, relay })
let params = sec.maybe(PARAMS).args_as_str().unwrap_or("").parse()?;
let status: &str = sec.required(VOTE_STATUS)?.arg(0).unwrap_or("");
if status != "consensus" {
return Err(EK::BadDocumentType.err());
// We're ignoring KNOWN_FLAGS in the consensus.
let consensus_method: u32 = sec.required(CONSENSUS_METHOD)?.parse_arg(0)?;
let shared_rand_previous_value = sec
.get(SHARED_RAND_PREVIOUS_VALUE)
.map(SharedRandStatus::from_item)
.transpose()?;
let shared_rand_current_value = sec
.get(SHARED_RAND_CURRENT_VALUE)
let voting_delay = if let Some(tok) = sec.get(VOTING_DELAY) {
let n1 = tok.parse_arg(0)?;
let n2 = tok.parse_arg(1)?;
Some((n1, n2))
None
let preamble = Preamble {
lifetime,
client_versions,
server_versions,
proto_statuses,
params,
voting_delay,
consensus_method,
published: NotPresent,
consensus_methods: NotPresent,
shared_rand_previous_value,
shared_rand_current_value,
Ok((flavor, preamble))
/// A Microdesc consensus whose signatures have not yet been checked.
/// To validate this object, call set_n_authorities() on it, then call
/// check_signature() on that result with the set of certs that you
/// have. Make sure only to provide authority certificates representing
/// real authorities!
pub struct UnvalidatedConsensus {
/// The consensus object. We don't want to expose this until it's
/// validated.
pub consensus: Consensus,
/// The signatures that need to be validated before we can call
/// this consensus valid.
pub siggroup: SignatureGroup,
/// The total number of authorities that we believe in. We need
/// this information in order to validate the signatures, since it
/// determines how many signatures we need to find valid in `siggroup`.
pub n_authorities: Option<usize>,
impl UnvalidatedConsensus {
/// Tell the unvalidated consensus how many authorities we believe in.
/// Without knowing this number, we can't validate the signature.
#[must_use]
pub fn set_n_authorities(self, n_authorities: usize) -> Self {
UnvalidatedConsensus {
n_authorities: Some(n_authorities),
..self
/// Return an iterator of all the certificate IDs that we might use
/// to validate this consensus.
pub fn signing_cert_ids(&self) -> impl Iterator<Item = AuthCertKeyIds> {
match self.key_is_correct(&[]) {
Ok(()) => Vec::new(),
Err(missing) => missing,
.into_iter()
/// Return the lifetime of this unvalidated consensus
pub fn peek_lifetime(&self) -> &Lifetime {
self.consensus.lifetime()
/// Return true if a client who believes in exactly the provided
/// set of authority IDs might consider this consensus to be
/// well-signed.
/// (This is the case if the consensus claims to be signed by more than
/// half of the authorities in the list.)
pub fn authorities_are_correct(&self, authorities: &[&RsaIdentity]) -> bool {
self.siggroup.could_validate(authorities)
/// Return the number of relays in this unvalidated consensus.
/// This function is unstable. It is only enabled if the crate was
/// built with the `experimental-api` feature.
#[cfg(feature = "experimental-api")]
pub fn n_relays(&self) -> usize {
self.consensus.relays.len()
/// Modify the list of relays in this unvalidated consensus.
/// A use case for this is long-lasting custom directories. To ensure Arti can still quickly
/// build circuits when the directory gets old, a tiny churn file can be regularly obtained,
/// listing no longer available Tor nodes, which can then be removed from the consensus.
pub fn modify_relays<F>(&mut self, func: F)
where
F: FnOnce(&mut Vec<RouterStatus>),
func(&mut self.consensus.relays);
impl ExternallySigned<Consensus> for UnvalidatedConsensus {
type Key = [AuthCert];
type KeyHint = Vec<AuthCertKeyIds>;
type Error = Error;
fn key_is_correct(&self, k: &Self::Key) -> result::Result<(), Self::KeyHint> {
let (n_ok, missing) = self.siggroup.list_missing(k);
match self.n_authorities {
Some(n) if n_ok > (n / 2) => Ok(()),
_ => Err(missing.iter().map(|cert| cert.key_ids).collect()),
fn is_well_signed(&self, k: &Self::Key) -> result::Result<(), Self::Error> {
None => Err(Error::from(internal!(
"Didn't set authorities on consensus"
))),
Some(authority) => {
if self.siggroup.validate(authority, k) {
Ok(())
Err(EK::BadSignature.err())
fn dangerously_assume_wellsigned(self) -> Consensus {
self.consensus
/// A Consensus object that has been parsed, but not checked for
/// signatures and timeliness.
pub type UncheckedConsensus = TimerangeBound<UnvalidatedConsensus>;