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Merge pull request #185 from poanetwork/revert-184-c0gent-mod-reorg 

Revert "Reorganize `dynamic_honey_badger` and `agreement` modules slightly."
This commit is contained in:
Nick Sanders 2018-08-02 12:59:41 -07:00 committed by GitHub
parent d74530004f c5977d1ab8
commit 5b3522b48b
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GPG Key ID: 4AEE18F83AFDEB23
14 changed files with 880 additions and 895 deletions
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3
examples/network/connection.rs
View File

@ -41,6 +41,7 @@ pub fn make(
TcpStream::connect(address).expect("failed to connect")
};
Connection::new(tcp_conn, there_str.to_string())
}).collect();
})
.collect();
(here_str, connections)
}

3
examples/network/node.rs
View File

@ -208,7 +208,8 @@ impl<T: Clone + Debug + AsRef<[u8]> + PartialEq + Send + Sync + From<Vec<u8>> +
.send(())
.map_err(|e| {
error!("{}", e);
}).unwrap();
})
.unwrap();
process::exit(0);
}) // end of thread scope

6
examples/simulation.rs
View File

@ -156,7 +156,8 @@ where
target: msg.target,
message: ser_msg,
}
}).collect();
})
.collect();
let outputs = step
.output
.into_iter()
@ -203,7 +204,8 @@ where
.map(|msg| {
let ser_msg = bincode::serialize(&msg.message).expect("serialize");
(msg.target, ser_msg)
}).collect();
})
.collect();
self.time += start.elapsed() * self.hw_quality.cpu_factor / 100;
let time = self.time;
self.outputs

422
src/agreement/agreement.rs
View File

@ -1,422 +0,0 @@
use std::collections::BTreeMap;
use std::fmt::Debug;
use std::sync::Arc;
use itertools::Itertools;
use super::bool_multimap::BoolMultimap;
use super::sbv_broadcast::{self, SbvBroadcast};
use super::{AgreementContent, AgreementMessage, Error, Nonce, Result, Step};
use agreement::bool_set::BoolSet;
use common_coin::{self, CommonCoin, CommonCoinMessage};
use messaging::{DistAlgorithm, NetworkInfo, Target};
/// The state of the current epoch's common coin. In some epochs this is fixed, in others it starts
/// with in `InProgress`.
#[derive(Debug)]
enum CoinState<NodeUid> {
/// The value was fixed in the current epoch, or the coin has already terminated.
Decided(bool),
/// The coin value is not known yet.
InProgress(CommonCoin<NodeUid, Nonce>),
}
impl<NodeUid> CoinState<NodeUid> {
/// Returns the value, if this coin has already decided.
fn value(&self) -> Option<bool> {
match self {
CoinState::Decided(value) => Some(*value),
CoinState::InProgress(_) => None,
}
}
}
impl<NodeUid> From<bool> for CoinState<NodeUid> {
fn from(value: bool) -> Self {
CoinState::Decided(value)
}
}
/// Binary Agreement instance
#[derive(Debug)]
pub struct Agreement<NodeUid> {
/// Shared network information.
netinfo: Arc<NetworkInfo<NodeUid>>,
/// Session ID, e.g, the Honey Badger algorithm epoch.
session_id: u64,
/// The ID of the proposer of the value for this agreement instance.
proposer_id: NodeUid,
/// Agreement algorithm epoch.
epoch: u32,
/// This epoch's Synchronized Binary Value Broadcast instance.
sbv_broadcast: SbvBroadcast<NodeUid>,
/// Received `Conf` messages. Reset on every epoch update.
received_conf: BTreeMap<NodeUid, BoolSet>,
/// Received `Term` messages. Kept throughout epoch updates. These count as `BVal`, `Aux` and
/// `Conf` messages for all future epochs.
received_term: BoolMultimap<NodeUid>,
/// The estimate of the decision value in the current epoch.
estimated: Option<bool>,
/// A permanent, latching copy of the output value. This copy is required because `output` can
/// be consumed using `DistAlgorithm::next_output` immediately after the instance finishing to
/// handle a message, in which case it would otherwise be unknown whether the output value was
/// ever there at all. While the output value will still be required in a later epoch to decide
/// the termination state.
decision: Option<bool>,
/// A cache for messages for future epochs that cannot be handled yet.
// TODO: Find a better solution for this; defend against spam.
incoming_queue: BTreeMap<u32, Vec<(NodeUid, AgreementContent)>>,
/// The values we found in the first _N - f_ `Aux` messages that were in `bin_values`.
conf_values: Option<BoolSet>,
/// The state of this epoch's common coin.
coin_state: CoinState<NodeUid>,
}
impl<NodeUid: Clone + Debug + Ord> DistAlgorithm for Agreement<NodeUid> {
type NodeUid = NodeUid;
type Input = bool;
type Output = bool;
type Message = AgreementMessage;
type Error = Error;
fn input(&mut self, input: Self::Input) -> Result<Step<NodeUid>> {
self.set_input(input)
}
/// Receive input from a remote node.
fn handle_message(
&mut self,
sender_id: &Self::NodeUid,
AgreementMessage { epoch, content }: Self::Message,
) -> Result<Step<NodeUid>> {
if self.decision.is_some() || (epoch < self.epoch && content.can_expire()) {
// Message is obsolete: We are already in a later epoch or terminated.
Ok(Step::default())
} else if epoch > self.epoch {
// Message is for a later epoch. We can't handle that yet.
let queue = self.incoming_queue.entry(epoch).or_insert_with(Vec::new);
queue.push((sender_id.clone(), content));
Ok(Step::default())
} else {
self.handle_message_content(sender_id, content)
}
}
/// Whether the algorithm has terminated.
fn terminated(&self) -> bool {
self.decision.is_some()
}
fn our_id(&self) -> &Self::NodeUid {
self.netinfo.our_uid()
}
}
impl<NodeUid: Clone + Debug + Ord> Agreement<NodeUid> {
pub fn new(
netinfo: Arc<NetworkInfo<NodeUid>>,
session_id: u64,
proposer_id: NodeUid,
) -> Result<Self> {
if !netinfo.is_node_validator(&proposer_id) {
return Err(Error::UnknownProposer);
}
Ok(Agreement {
netinfo: netinfo.clone(),
session_id,
proposer_id,
epoch: 0,
sbv_broadcast: SbvBroadcast::new(netinfo),
received_conf: BTreeMap::new(),
received_term: BoolMultimap::default(),
estimated: None,
decision: None,
incoming_queue: BTreeMap::new(),
conf_values: None,
coin_state: CoinState::Decided(true),
})
}
/// Sets the input value for agreement.
fn set_input(&mut self, input: bool) -> Result<Step<NodeUid>> {
if self.epoch != 0 || self.estimated.is_some() {
return Err(Error::InputNotAccepted);
}
// Set the initial estimated value to the input value.
self.estimated = Some(input);
debug!("{:?}/{:?} Input {}", self.our_id(), self.proposer_id, input);
let sbvb_step = self.sbv_broadcast.input(input)?;
self.handle_sbvb_step(sbvb_step)
}
/// Acceptance check to be performed before setting the input value.
pub fn accepts_input(&self) -> bool {
self.epoch == 0 && self.estimated.is_none()
}
/// Dispatches the message content to the corresponding handling method.
fn handle_message_content(
&mut self,
sender_id: &NodeUid,
content: AgreementContent,
) -> Result<Step<NodeUid>> {
match content {
AgreementContent::SbvBroadcast(msg) => self.handle_sbv_broadcast(sender_id, msg),
AgreementContent::Conf(v) => self.handle_conf(sender_id, v),
AgreementContent::Term(v) => self.handle_term(sender_id, v),
AgreementContent::Coin(msg) => self.handle_coin(sender_id, *msg),
}
}
/// Handles a Synchroniced Binary Value Broadcast message.
fn handle_sbv_broadcast(
&mut self,
sender_id: &NodeUid,
msg: sbv_broadcast::Message,
) -> Result<Step<NodeUid>> {
let sbvb_step = self.sbv_broadcast.handle_message(sender_id, msg)?;
self.handle_sbvb_step(sbvb_step)
}
/// Handles a Synchronized Binary Value Broadcast step. On output, starts the `Conf` round or
/// decides.
fn handle_sbvb_step(
&mut self,
sbvb_step: sbv_broadcast::Step<NodeUid>,
) -> Result<Step<NodeUid>> {
let mut step = Step::default();
let output = step.extend_with(sbvb_step, |msg| {
AgreementContent::SbvBroadcast(msg).with_epoch(self.epoch)
});
if self.conf_values.is_some() {
return Ok(step); // The `Conf` round has already started.
}
if let Some(aux_vals) = output.into_iter().next() {
// Execute the Common Coin schedule `false, true, get_coin(), false, true, get_coin(), ...`
match self.coin_state {
CoinState::Decided(_) => {
self.conf_values = Some(aux_vals);
step.extend(self.try_update_epoch()?)
}
CoinState::InProgress(_) => {
// Start the `Conf` message round.
step.extend(self.send_conf(aux_vals)?)
}
}
}
Ok(step)
}
/// Handles a `Conf` message. When _N - f_ `Conf` messages with values in `bin_values` have
/// been received, updates the epoch or decides.
fn handle_conf(&mut self, sender_id: &NodeUid, v: BoolSet) -> Result<Step<NodeUid>> {
self.received_conf.insert(sender_id.clone(), v);
self.try_finish_conf_round()
}
/// Handles a `Term(v)` message. If we haven't yet decided on a value and there are more than
/// _f_ such messages with the same value from different nodes, performs expedite termination:
/// decides on `v`, broadcasts `Term(v)` and terminates the instance.
fn handle_term(&mut self, sender_id: &NodeUid, b: bool) -> Result<Step<NodeUid>> {
self.received_term[b].insert(sender_id.clone());
// Check for the expedite termination condition.
if self.decision.is_some() {
Ok(Step::default())
} else if self.received_term[b].len() > self.netinfo.num_faulty() {
Ok(self.decide(b))
} else {
// Otherwise handle the `Term` as a `BVal`, `Aux` and `Conf`.
let mut sbvb_step = self.sbv_broadcast.handle_bval(sender_id, b)?;
sbvb_step.extend(self.sbv_broadcast.handle_aux(sender_id, b)?);
let mut step = self.handle_sbvb_step(sbvb_step)?;
step.extend(self.handle_conf(sender_id, BoolSet::from(b))?);
Ok(step)
}
}
/// Handles a Common Coin message. If there is output from Common Coin, starts the next
/// epoch. The function may output a decision value.
fn handle_coin(
&mut self,
sender_id: &NodeUid,
msg: CommonCoinMessage,
) -> Result<Step<NodeUid>> {
let coin_step = match self.coin_state {
CoinState::Decided(_) => return Ok(Step::default()), // Coin value is already decided.
CoinState::InProgress(ref mut common_coin) => common_coin
.handle_message(sender_id, msg)
.map_err(Error::HandleCoinCommonCoin)?,
};
self.on_coin_step(coin_step)
}
/// Multicasts a `Conf(values)` message, and handles it.
fn send_conf(&mut self, values: BoolSet) -> Result<Step<NodeUid>> {
if self.conf_values.is_some() {
// Only one `Conf` message is allowed in an epoch.
return Ok(Step::default());
}
// Trigger the start of the `Conf` round.
self.conf_values = Some(values);
if !self.netinfo.is_validator() {
return Ok(self.try_finish_conf_round()?);
}
self.send(AgreementContent::Conf(values))
}
/// Multicasts and handles a message. Does nothing if we are only an observer.
fn send(&mut self, content: AgreementContent) -> Result<Step<NodeUid>> {
if !self.netinfo.is_validator() {
return Ok(Step::default());
}
let mut step: Step<_> = Target::All
.message(content.clone().with_epoch(self.epoch))
.into();
let our_uid = &self.netinfo.our_uid().clone();
step.extend(self.handle_message_content(our_uid, content)?);
Ok(step)
}
/// Handles a step returned from the `CommonCoin`.
fn on_coin_step(
&mut self,
coin_step: common_coin::Step<NodeUid, Nonce>,
) -> Result<Step<NodeUid>> {
let mut step = Step::default();
let epoch = self.epoch;
let to_msg = |c_msg| AgreementContent::Coin(Box::new(c_msg)).with_epoch(epoch);
let coin_output = step.extend_with(coin_step, to_msg);
if let Some(coin) = coin_output.into_iter().next() {
self.coin_state = coin.into();
step.extend(self.try_update_epoch()?);
}
Ok(step)
}
/// If this epoch's coin value or conf values are not known yet, does nothing, otherwise
/// updates the epoch or decides.
///
/// With two conf values, the next epoch's estimate is the coin value. If there is only one conf
/// value and that disagrees with the coin, the conf value is the next epoch's estimate. If
/// the unique conf value agrees with the coin, terminates and decides on that value.
fn try_update_epoch(&mut self) -> Result<Step<NodeUid>> {
if self.decision.is_some() {
// Avoid an infinite regression without making an Agreement step.
return Ok(Step::default());
}
let coin = match self.coin_state.value() {
None => return Ok(Step::default()), // Still waiting for coin value.
Some(coin) => coin,
};
let def_bin_value = match self.conf_values {
None => return Ok(Step::default()), // Still waiting for conf value.
Some(ref values) => values.definite(),
};
if Some(coin) == def_bin_value {
Ok(self.decide(coin))
} else {
self.update_epoch(def_bin_value.unwrap_or(coin))
}
}
/// Creates the initial coin state for the current epoch, i.e. sets it to the predetermined
/// value, or initializes a `CommonCoin` instance.
fn coin_state(&self) -> CoinState<NodeUid> {
match self.epoch % 3 {
0 => CoinState::Decided(true),
1 => CoinState::Decided(false),
_ => {
let nonce = Nonce::new(
self.netinfo.invocation_id().as_ref(),
self.session_id,
self.netinfo.node_index(&self.proposer_id).unwrap(),
self.epoch,
);
CoinState::InProgress(CommonCoin::new(self.netinfo.clone(), nonce))
}
}
}
/// Decides on a value and broadcasts a `Term` message with that value.
fn decide(&mut self, b: bool) -> Step<NodeUid> {
if self.decision.is_some() {
return Step::default();
}
// Output the agreement value.
let mut step = Step::default();
step.output.push_back(b);
// Latch the decided state.
self.decision = Some(b);
debug!(
"{:?}/{:?} (is_validator: {}) decision: {}",
self.netinfo.our_uid(),
self.proposer_id,
self.netinfo.is_validator(),
b
);
if self.netinfo.is_validator() {
let msg = AgreementContent::Term(b).with_epoch(self.epoch + 1);
step.messages.push_back(Target::All.message(msg));
}
step
}
/// Checks whether the _N - f_ `Conf` messages have arrived, and if so, activates the coin.
fn try_finish_conf_round(&mut self) -> Result<Step<NodeUid>> {
if self.conf_values.is_none() || self.count_conf() < self.netinfo.num_correct() {
return Ok(Step::default());
}
// Invoke the common coin.
let coin_step = match self.coin_state {
CoinState::Decided(_) => return Ok(Step::default()), // Coin has already decided.
CoinState::InProgress(ref mut common_coin) => common_coin
.input(())
.map_err(Error::TryFinishConfRoundCommonCoin)?,
};
let mut step = self.on_coin_step(coin_step)?;
step.extend(self.try_update_epoch()?);
Ok(step)
}
/// Counts the number of received `Conf` messages with values in `bin_values`.
fn count_conf(&self) -> usize {
let is_bin_val = |conf: &&BoolSet| conf.is_subset(self.sbv_broadcast.bin_values());
self.received_conf.values().filter(is_bin_val).count()
}
/// Increments the epoch, sets the new estimate and handles queued messages.
fn update_epoch(&mut self, b: bool) -> Result<Step<NodeUid>> {
self.sbv_broadcast.clear(&self.received_term);
self.received_conf.clear();
for (v, id) in &self.received_term {
self.received_conf.insert(id.clone(), BoolSet::from(v));
}
self.conf_values = None;
self.epoch += 1;
self.coin_state = self.coin_state();
debug!(
"{:?} Agreement instance {:?} started epoch {}, {} terminated",
self.netinfo.our_uid(),
self.proposer_id,
self.epoch,
self.received_conf.len(),
);
self.estimated = Some(b);
let sbvb_step = self.sbv_broadcast.input(b)?;
let mut step = self.handle_sbvb_step(sbvb_step)?;
let queued_msgs = Itertools::flatten(self.incoming_queue.remove(&self.epoch).into_iter());
for (sender_id, content) in queued_msgs {
step.extend(self.handle_message_content(&sender_id, content)?);
if self.decision.is_some() {
break;
}
}
Ok(step)
}
}

428
src/agreement/mod.rs
View File

@ -63,18 +63,22 @@
//! * After _f + 1_ nodes have sent us their coin shares, we receive the coin output and assign it
//! to `s`.
mod agreement;
mod bool_multimap;
pub mod bool_set;
mod sbv_broadcast;
use rand;
use std::collections::BTreeMap;
use std::fmt::Debug;
use std::sync::Arc;
use self::bool_set::BoolSet;
use common_coin::{self, CommonCoinMessage};
use messaging;
use itertools::Itertools;
pub use self::agreement::Agreement;
use self::bool_multimap::BoolMultimap;
use self::sbv_broadcast::SbvBroadcast;
use agreement::bool_set::BoolSet;
use common_coin::{self, CommonCoin, CommonCoinMessage};
use messaging::{self, DistAlgorithm, NetworkInfo, Target};
/// An agreement error.
#[derive(Clone, Eq, PartialEq, Debug, Fail)]
@ -92,8 +96,6 @@ pub enum Error {
/// An agreement result.
pub type Result<T> = ::std::result::Result<T, Error>;
pub type Step<NodeUid> = messaging::Step<Agreement<NodeUid>>;
#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
pub enum AgreementContent {
/// Synchronized Binary Value Broadcast message.
@ -148,6 +150,418 @@ impl rand::Rand for AgreementContent {
}
}
/// The state of the current epoch's common coin. In some epochs this is fixed, in others it starts
/// with in `InProgress`.
#[derive(Debug)]
enum CoinState<NodeUid> {
/// The value was fixed in the current epoch, or the coin has already terminated.
Decided(bool),
/// The coin value is not known yet.
InProgress(CommonCoin<NodeUid, Nonce>),
}
impl<NodeUid> CoinState<NodeUid> {
/// Returns the value, if this coin has already decided.
fn value(&self) -> Option<bool> {
match self {
CoinState::Decided(value) => Some(*value),
CoinState::InProgress(_) => None,
}
}
}
impl<NodeUid> From<bool> for CoinState<NodeUid> {
fn from(value: bool) -> Self {
CoinState::Decided(value)
}
}
/// Binary Agreement instance
#[derive(Debug)]
pub struct Agreement<NodeUid> {
/// Shared network information.
netinfo: Arc<NetworkInfo<NodeUid>>,
/// Session ID, e.g, the Honey Badger algorithm epoch.
session_id: u64,
/// The ID of the proposer of the value for this agreement instance.
proposer_id: NodeUid,
/// Agreement algorithm epoch.
epoch: u32,
/// This epoch's Synchronized Binary Value Broadcast instance.
sbv_broadcast: SbvBroadcast<NodeUid>,
/// Received `Conf` messages. Reset on every epoch update.
received_conf: BTreeMap<NodeUid, BoolSet>,
/// Received `Term` messages. Kept throughout epoch updates. These count as `BVal`, `Aux` and
/// `Conf` messages for all future epochs.
received_term: BoolMultimap<NodeUid>,
/// The estimate of the decision value in the current epoch.
estimated: Option<bool>,
/// A permanent, latching copy of the output value. This copy is required because `output` can
/// be consumed using `DistAlgorithm::next_output` immediately after the instance finishing to
/// handle a message, in which case it would otherwise be unknown whether the output value was
/// ever there at all. While the output value will still be required in a later epoch to decide
/// the termination state.
decision: Option<bool>,
/// A cache for messages for future epochs that cannot be handled yet.
// TODO: Find a better solution for this; defend against spam.
incoming_queue: BTreeMap<u32, Vec<(NodeUid, AgreementContent)>>,
/// The values we found in the first _N - f_ `Aux` messages that were in `bin_values`.
conf_values: Option<BoolSet>,
/// The state of this epoch's common coin.
coin_state: CoinState<NodeUid>,
}
pub type Step<NodeUid> = messaging::Step<Agreement<NodeUid>>;
impl<NodeUid: Clone + Debug + Ord> DistAlgorithm for Agreement<NodeUid> {
type NodeUid = NodeUid;
type Input = bool;
type Output = bool;
type Message = AgreementMessage;
type Error = Error;
fn input(&mut self, input: Self::Input) -> Result<Step<NodeUid>> {
self.set_input(input)
}
/// Receive input from a remote node.
fn handle_message(
&mut self,
sender_id: &Self::NodeUid,
AgreementMessage { epoch, content }: Self::Message,
) -> Result<Step<NodeUid>> {
if self.decision.is_some() || (epoch < self.epoch && content.can_expire()) {
// Message is obsolete: We are already in a later epoch or terminated.
Ok(Step::default())
} else if epoch > self.epoch {
// Message is for a later epoch. We can't handle that yet.
let queue = self.incoming_queue.entry(epoch).or_insert_with(Vec::new);
queue.push((sender_id.clone(), content));
Ok(Step::default())
} else {
self.handle_message_content(sender_id, content)
}
}
/// Whether the algorithm has terminated.
fn terminated(&self) -> bool {
self.decision.is_some()
}
fn our_id(&self) -> &Self::NodeUid {
self.netinfo.our_uid()
}
}
impl<NodeUid: Clone + Debug + Ord> Agreement<NodeUid> {
pub fn new(
netinfo: Arc<NetworkInfo<NodeUid>>,
session_id: u64,
proposer_id: NodeUid,
) -> Result<Self> {
if !netinfo.is_node_validator(&proposer_id) {
return Err(Error::UnknownProposer);
}
Ok(Agreement {
netinfo: netinfo.clone(),
session_id,
proposer_id,
epoch: 0,
sbv_broadcast: SbvBroadcast::new(netinfo),
received_conf: BTreeMap::new(),
received_term: BoolMultimap::default(),
estimated: None,
decision: None,
incoming_queue: BTreeMap::new(),
conf_values: None,
coin_state: CoinState::Decided(true),
})
}
/// Sets the input value for agreement.
fn set_input(&mut self, input: bool) -> Result<Step<NodeUid>> {
if self.epoch != 0 || self.estimated.is_some() {
return Err(Error::InputNotAccepted);
}
// Set the initial estimated value to the input value.
self.estimated = Some(input);
debug!("{:?}/{:?} Input {}", self.our_id(), self.proposer_id, input);
let sbvb_step = self.sbv_broadcast.input(input)?;
self.handle_sbvb_step(sbvb_step)
}
/// Acceptance check to be performed before setting the input value.
pub fn accepts_input(&self) -> bool {
self.epoch == 0 && self.estimated.is_none()
}
/// Dispatches the message content to the corresponding handling method.
fn handle_message_content(
&mut self,
sender_id: &NodeUid,
content: AgreementContent,
) -> Result<Step<NodeUid>> {
match content {
AgreementContent::SbvBroadcast(msg) => self.handle_sbv_broadcast(sender_id, msg),
AgreementContent::Conf(v) => self.handle_conf(sender_id, v),
AgreementContent::Term(v) => self.handle_term(sender_id, v),
AgreementContent::Coin(msg) => self.handle_coin(sender_id, *msg),
}
}
/// Handles a Synchroniced Binary Value Broadcast message.
fn handle_sbv_broadcast(
&mut self,
sender_id: &NodeUid,
msg: sbv_broadcast::Message,
) -> Result<Step<NodeUid>> {
let sbvb_step = self.sbv_broadcast.handle_message(sender_id, msg)?;
self.handle_sbvb_step(sbvb_step)
}
/// Handles a Synchronized Binary Value Broadcast step. On output, starts the `Conf` round or
/// decides.
fn handle_sbvb_step(
&mut self,
sbvb_step: sbv_broadcast::Step<NodeUid>,
) -> Result<Step<NodeUid>> {
let mut step = Step::default();
let output = step.extend_with(sbvb_step, |msg| {
AgreementContent::SbvBroadcast(msg).with_epoch(self.epoch)
});
if self.conf_values.is_some() {
return Ok(step); // The `Conf` round has already started.
}
if let Some(aux_vals) = output.into_iter().next() {
// Execute the Common Coin schedule `false, true, get_coin(), false, true, get_coin(), ...`
match self.coin_state {
CoinState::Decided(_) => {
self.conf_values = Some(aux_vals);
step.extend(self.try_update_epoch()?)
}
CoinState::InProgress(_) => {
// Start the `Conf` message round.
step.extend(self.send_conf(aux_vals)?)
}
}
}
Ok(step)
}
/// Handles a `Conf` message. When _N - f_ `Conf` messages with values in `bin_values` have
/// been received, updates the epoch or decides.
fn handle_conf(&mut self, sender_id: &NodeUid, v: BoolSet) -> Result<Step<NodeUid>> {
self.received_conf.insert(sender_id.clone(), v);
self.try_finish_conf_round()
}
/// Handles a `Term(v)` message. If we haven't yet decided on a value and there are more than
/// _f_ such messages with the same value from different nodes, performs expedite termination:
/// decides on `v`, broadcasts `Term(v)` and terminates the instance.
fn handle_term(&mut self, sender_id: &NodeUid, b: bool) -> Result<Step<NodeUid>> {
self.received_term[b].insert(sender_id.clone());
// Check for the expedite termination condition.
if self.decision.is_some() {
Ok(Step::default())
} else if self.received_term[b].len() > self.netinfo.num_faulty() {
Ok(self.decide(b))
} else {
// Otherwise handle the `Term` as a `BVal`, `Aux` and `Conf`.
let mut sbvb_step = self.sbv_broadcast.handle_bval(sender_id, b)?;
sbvb_step.extend(self.sbv_broadcast.handle_aux(sender_id, b)?);
let mut step = self.handle_sbvb_step(sbvb_step)?;
step.extend(self.handle_conf(sender_id, BoolSet::from(b))?);
Ok(step)
}
}
/// Handles a Common Coin message. If there is output from Common Coin, starts the next
/// epoch. The function may output a decision value.
fn handle_coin(
&mut self,
sender_id: &NodeUid,
msg: CommonCoinMessage,
) -> Result<Step<NodeUid>> {
let coin_step = match self.coin_state {
CoinState::Decided(_) => return Ok(Step::default()), // Coin value is already decided.
CoinState::InProgress(ref mut common_coin) => common_coin
.handle_message(sender_id, msg)
.map_err(Error::HandleCoinCommonCoin)?,
};
self.on_coin_step(coin_step)
}
/// Multicasts a `Conf(values)` message, and handles it.
fn send_conf(&mut self, values: BoolSet) -> Result<Step<NodeUid>> {
if self.conf_values.is_some() {
// Only one `Conf` message is allowed in an epoch.
return Ok(Step::default());
}
// Trigger the start of the `Conf` round.
self.conf_values = Some(values);
if !self.netinfo.is_validator() {
return Ok(self.try_finish_conf_round()?);
}
self.send(AgreementContent::Conf(values))
}
/// Multicasts and handles a message. Does nothing if we are only an observer.
fn send(&mut self, content: AgreementContent) -> Result<Step<NodeUid>> {
if !self.netinfo.is_validator() {
return Ok(Step::default());
}
let mut step: Step<_> = Target::All
.message(content.clone().with_epoch(self.epoch))
.into();
let our_uid = &self.netinfo.our_uid().clone();
step.extend(self.handle_message_content(our_uid, content)?);
Ok(step)
}
/// Handles a step returned from the `CommonCoin`.
fn on_coin_step(
&mut self,
coin_step: common_coin::Step<NodeUid, Nonce>,
) -> Result<Step<NodeUid>> {
let mut step = Step::default();
let epoch = self.epoch;
let to_msg = |c_msg| AgreementContent::Coin(Box::new(c_msg)).with_epoch(epoch);
let coin_output = step.extend_with(coin_step, to_msg);
if let Some(coin) = coin_output.into_iter().next() {
self.coin_state = coin.into();
step.extend(self.try_update_epoch()?);
}
Ok(step)
}
/// If this epoch's coin value or conf values are not known yet, does nothing, otherwise
/// updates the epoch or decides.
///
/// With two conf values, the next epoch's estimate is the coin value. If there is only one conf
/// value and that disagrees with the coin, the conf value is the next epoch's estimate. If
/// the unique conf value agrees with the coin, terminates and decides on that value.
fn try_update_epoch(&mut self) -> Result<Step<NodeUid>> {
if self.decision.is_some() {
// Avoid an infinite regression without making an Agreement step.
return Ok(Step::default());
}
let coin = match self.coin_state.value() {
None => return Ok(Step::default()), // Still waiting for coin value.
Some(coin) => coin,
};
let def_bin_value = match self.conf_values {
None => return Ok(Step::default()), // Still waiting for conf value.
Some(ref values) => values.definite(),
};
if Some(coin) == def_bin_value {
Ok(self.decide(coin))
} else {
self.update_epoch(def_bin_value.unwrap_or(coin))
}
}
/// Creates the initial coin state for the current epoch, i.e. sets it to the predetermined
/// value, or initializes a `CommonCoin` instance.
fn coin_state(&self) -> CoinState<NodeUid> {
match self.epoch % 3 {
0 => CoinState::Decided(true),
1 => CoinState::Decided(false),
_ => {
let nonce = Nonce::new(
self.netinfo.invocation_id().as_ref(),
self.session_id,
self.netinfo.node_index(&self.proposer_id).unwrap(),
self.epoch,
);
CoinState::InProgress(CommonCoin::new(self.netinfo.clone(), nonce))
}
}
}
/// Decides on a value and broadcasts a `Term` message with that value.
fn decide(&mut self, b: bool) -> Step<NodeUid> {
if self.decision.is_some() {
return Step::default();
}
// Output the agreement value.
let mut step = Step::default();
step.output.push_back(b);
// Latch the decided state.
self.decision = Some(b);
debug!(
"{:?}/{:?} (is_validator: {}) decision: {}",
self.netinfo.our_uid(),
self.proposer_id,
self.netinfo.is_validator(),
b
);
if self.netinfo.is_validator() {
let msg = AgreementContent::Term(b).with_epoch(self.epoch + 1);
step.messages.push_back(Target::All.message(msg));
}
step
}
/// Checks whether the _N - f_ `Conf` messages have arrived, and if so, activates the coin.
fn try_finish_conf_round(&mut self) -> Result<Step<NodeUid>> {
if self.conf_values.is_none() || self.count_conf() < self.netinfo.num_correct() {
return Ok(Step::default());
}
// Invoke the common coin.
let coin_step = match self.coin_state {
CoinState::Decided(_) => return Ok(Step::default()), // Coin has already decided.
CoinState::InProgress(ref mut common_coin) => common_coin
.input(())
.map_err(Error::TryFinishConfRoundCommonCoin)?,
};
let mut step = self.on_coin_step(coin_step)?;
step.extend(self.try_update_epoch()?);
Ok(step)
}
/// Counts the number of received `Conf` messages with values in `bin_values`.
fn count_conf(&self) -> usize {
let is_bin_val = |conf: &&BoolSet| conf.is_subset(self.sbv_broadcast.bin_values());
self.received_conf.values().filter(is_bin_val).count()
}
/// Increments the epoch, sets the new estimate and handles queued messages.
fn update_epoch(&mut self, b: bool) -> Result<Step<NodeUid>> {
self.sbv_broadcast.clear(&self.received_term);
self.received_conf.clear();
for (v, id) in &self.received_term {
self.received_conf.insert(id.clone(), BoolSet::from(v));
}
self.conf_values = None;
self.epoch += 1;
self.coin_state = self.coin_state();
debug!(
"{:?} Agreement instance {:?} started epoch {}, {} terminated",
self.netinfo.our_uid(),
self.proposer_id,
self.epoch,
self.received_conf.len(),
);
self.estimated = Some(b);
let sbvb_step = self.sbv_broadcast.input(b)?;
let mut step = self.handle_sbvb_step(sbvb_step)?;
let queued_msgs = Itertools::flatten(self.incoming_queue.remove(&self.epoch).into_iter());
for (sender_id, content) in queued_msgs {
step.extend(self.handle_message_content(&sender_id, content)?);
if self.decision.is_some() {
break;
}
}
Ok(step)
}
}
#[derive(Clone, Debug)]
struct Nonce(Vec<u8>);

3
src/broadcast.rs
View File

@ -541,7 +541,8 @@ impl<NodeUid: Debug + Clone + Ord> Broadcast<NodeUid> {
None
}
})
}).collect();
})
.collect();
if let Some(value) =
decode_from_shards(&mut leaf_values, &self.coding, self.data_shard_num, hash)
{

3
src/common_subset.rs
View File

@ -129,8 +129,7 @@ impl<NodeUid: Clone + Debug + Ord + Rand> CommonSubset<NodeUid> {
for proposer_id in netinfo.all_uids() {
broadcast_instances.insert(
proposer_id.clone(),
Broadcast::new(netinfo.clone(), proposer_id.clone())
.map_err(Error::NewBroadcast)?,
Broadcast::new(netinfo.clone(), proposer_id.clone()).map_err(Error::NewBroadcast)?,
);
}

419
src/dynamic_honey_badger/dynamic_honey_badger.rs
View File

@ -1,419 +0,0 @@
use rand::Rand;
use std::fmt::Debug;
use std::hash::Hash;
use std::mem;
use std::sync::Arc;
use bincode;
use crypto::Signature;
use serde::{Deserialize, Serialize};
use super::votes::{SignedVote, VoteCounter};
use super::{
Batch, Change, ChangeState, DynamicHoneyBadgerBuilder, Error, ErrorKind, Input,
InternalContrib, KeyGenMessage, KeyGenState, Message, Result, SignedKeyGenMsg, Step,
};
use fault_log::{Fault, FaultKind, FaultLog};
use honey_badger::{self, HoneyBadger, Message as HbMessage};
use messaging::{DistAlgorithm, NetworkInfo, Target};
use sync_key_gen::{Ack, Part, PartOutcome, SyncKeyGen};
/// A Honey Badger instance that can handle adding and removing nodes.
#[derive(Debug)]
pub struct DynamicHoneyBadger<C, NodeUid: Rand> {
/// Shared network data.
pub(super) netinfo: NetworkInfo<NodeUid>,
/// The maximum number of future epochs for which we handle messages simultaneously.
pub(super) max_future_epochs: usize,
/// The first epoch after the latest node change.
pub(super) start_epoch: u64,
/// The buffer and counter for the pending and committed change votes.
pub(super) vote_counter: VoteCounter<NodeUid>,
/// Pending node transactions that we will propose in the next epoch.
pub(super) key_gen_msg_buffer: Vec<SignedKeyGenMsg<NodeUid>>,
/// The `HoneyBadger` instance with the current set of nodes.
pub(super) honey_badger: HoneyBadger<InternalContrib<C, NodeUid>, NodeUid>,
/// The current key generation process, and the change it applies to.
pub(super) key_gen_state: Option<KeyGenState<NodeUid>>,
/// A queue for messages from future epochs that cannot be handled yet.
pub(super) incoming_queue: Vec<(NodeUid, Message<NodeUid>)>,
}
impl<C, NodeUid> DistAlgorithm for DynamicHoneyBadger<C, NodeUid>
where
C: Eq + Serialize + for<'r> Deserialize<'r> + Debug + Hash,
NodeUid: Eq + Ord + Clone + Serialize + for<'r> Deserialize<'r> + Debug + Hash + Rand,
{
type NodeUid = NodeUid;
type Input = Input<C, NodeUid>;
type Output = Batch<C, NodeUid>;
type Message = Message<NodeUid>;
type Error = Error;
fn input(&mut self, input: Self::Input) -> Result<Step<C, NodeUid>> {
// User contributions are forwarded to `HoneyBadger` right away. Votes are signed and
// broadcast.
match input {
Input::User(contrib) => self.propose(contrib),
Input::Change(change) => self.vote_for(change),
}
}
fn handle_message(
&mut self,
sender_id: &NodeUid,
message: Self::Message,
) -> Result<Step<C, NodeUid>> {
let epoch = message.start_epoch();
if epoch < self.start_epoch {
// Obsolete message.
Ok(Step::default())
} else if epoch > self.start_epoch {
// Message cannot be handled yet. Save it for later.
let entry = (sender_id.clone(), message);
self.incoming_queue.push(entry);
Ok(Step::default())
} else {
match message {
Message::HoneyBadger(_, hb_msg) => {
self.handle_honey_badger_message(sender_id, hb_msg)
}
Message::KeyGen(_, kg_msg, sig) => self
.handle_key_gen_message(sender_id, kg_msg, *sig)
.map(FaultLog::into),
Message::SignedVote(signed_vote) => self
.vote_counter
.add_pending_vote(sender_id, signed_vote)
.map(FaultLog::into),
}
}
}
fn terminated(&self) -> bool {
false
}
fn our_id(&self) -> &NodeUid {
self.netinfo.our_uid()
}
}
impl<C, NodeUid> DynamicHoneyBadger<C, NodeUid>
where
C: Eq + Serialize + for<'r> Deserialize<'r> + Debug + Hash,
NodeUid: Eq + Ord + Clone + Debug + Serialize + for<'r> Deserialize<'r> + Hash + Rand,
{
/// Returns a new `DynamicHoneyBadgerBuilder`.
pub fn builder() -> DynamicHoneyBadgerBuilder<C, NodeUid> {
DynamicHoneyBadgerBuilder::new()
}
/// Returns `true` if input for the current epoch has already been provided.
pub fn has_input(&self) -> bool {
self.honey_badger.has_input()
}
/// Proposes a contribution in the current epoch.
pub fn propose(&mut self, contrib: C) -> Result<Step<C, NodeUid>> {
let step = self
.honey_badger
.input(InternalContrib {
contrib,
key_gen_messages: self.key_gen_msg_buffer.clone(),
votes: self.vote_counter.pending_votes().cloned().collect(),
}).map_err(ErrorKind::ProposeHoneyBadger)?;
self.process_output(step)
}
/// Cast a vote to change the set of validators.
pub fn vote_for(&mut self, change: Change<NodeUid>) -> Result<Step<C, NodeUid>> {
if !self.netinfo.is_validator() {
return Ok(Step::default()); // TODO: Return an error?
}
let signed_vote = self.vote_counter.sign_vote_for(change)?.clone();
let msg = Message::SignedVote(signed_vote);
Ok(Target::All.message(msg).into())
}
/// Returns the information about the node IDs in the network, and the cryptographic keys.
pub fn netinfo(&self) -> &NetworkInfo<NodeUid> {
&self.netinfo
}
/// Returns `true` if we should make our contribution for the next epoch, even if we don't have
/// content ourselves, to avoid stalling the network.
///
/// By proposing only if this returns `true`, you can prevent an adversary from making the
/// network output empty baches indefinitely, but it also means that the network won't advance
/// if fewer than _f + 1_ nodes have pending contributions.
pub fn should_propose(&self) -> bool {
if self.has_input() {
return false; // We have already proposed.
}
if self.honey_badger.received_proposals() > self.netinfo.num_faulty() {
return true; // At least one correct node wants to move on to the next epoch.
}
let is_our_vote = |signed_vote: &SignedVote<_>| signed_vote.voter() == self.our_id();
if self.vote_counter.pending_votes().any(is_our_vote) {
return true; // We have pending input to vote for a validator change.
}
let kgs = match self.key_gen_state {
None => return false, // No ongoing key generation.
Some(ref kgs) => kgs,
};
// If either we or the candidate have a pending key gen message, we should propose.
let ours_or_candidates = |msg: &SignedKeyGenMsg<_>| {
msg.1 == *self.our_id() || Some(&msg.1) == kgs.change.candidate()
};
self.key_gen_msg_buffer.iter().any(ours_or_candidates)
}
/// Handles a message for the `HoneyBadger` instance.
fn handle_honey_badger_message(
&mut self,
sender_id: &NodeUid,
message: HbMessage<NodeUid>,
) -> Result<Step<C, NodeUid>> {
if !self.netinfo.is_node_validator(sender_id) {
info!("Unknown sender {:?} of message {:?}", sender_id, message);
return Err(ErrorKind::UnknownSender.into());
}
// Handle the message.
let step = self
.honey_badger
.handle_message(sender_id, message)
.map_err(ErrorKind::HandleHoneyBadgerMessageHoneyBadger)?;
self.process_output(step)
}
/// Handles a vote or key generation message and tries to commit it as a transaction. These
/// messages are only handled once they appear in a batch output from Honey Badger.
fn handle_key_gen_message(
&mut self,
sender_id: &NodeUid,
kg_msg: KeyGenMessage,
sig: Signature,
) -> Result<FaultLog<NodeUid>> {
if !self.verify_signature(sender_id, &sig, &kg_msg)? {
info!("Invalid signature from {:?} for: {:?}.", sender_id, kg_msg);
let fault_kind = FaultKind::InvalidKeyGenMessageSignature;
return Ok(Fault::new(sender_id.clone(), fault_kind).into());
}
let kgs = match self.key_gen_state {
Some(ref mut kgs) => kgs,
None => {
info!(
"Unexpected key gen message from {:?}: {:?}.",
sender_id, kg_msg
);
return Ok(Fault::new(sender_id.clone(), FaultKind::UnexpectedKeyGenMessage).into());
}
};
// If the joining node is correct, it will send at most (N + 1)² + 1 key generation
// messages.
if Some(sender_id) == kgs.change.candidate() {
let n = self.netinfo.num_nodes() + 1;
if kgs.candidate_msg_count > n * n {
info!(
"Too many key gen messages from candidate {:?}: {:?}.",
sender_id, kg_msg
);
let fault_kind = FaultKind::TooManyCandidateKeyGenMessages;
return Ok(Fault::new(sender_id.clone(), fault_kind).into());
}
kgs.candidate_msg_count += 1;
}
let tx = SignedKeyGenMsg(self.start_epoch, sender_id.clone(), kg_msg, sig);
self.key_gen_msg_buffer.push(tx);
Ok(FaultLog::default())
}
/// Processes all pending batches output by Honey Badger.
fn process_output(
&mut self,
hb_step: honey_badger::Step<InternalContrib<C, NodeUid>, NodeUid>,
) -> Result<Step<C, NodeUid>> {
let mut step: Step<C, NodeUid> = Step::default();
let start_epoch = self.start_epoch;
let output = step.extend_with(hb_step, |hb_msg| Message::HoneyBadger(start_epoch, hb_msg));
for hb_batch in output {
// Create the batch we output ourselves. It will contain the _user_ transactions of
// `hb_batch`, and the current change state.
let mut batch = Batch::new(hb_batch.epoch + self.start_epoch);
// Add the user transactions to `batch` and handle votes and DKG messages.
for (id, int_contrib) in hb_batch.contributions {
let InternalContrib {
votes,
key_gen_messages,
contrib,
} = int_contrib;
step.fault_log
.extend(self.vote_counter.add_committed_votes(&id, votes)?);
batch.contributions.insert(id.clone(), contrib);
self.key_gen_msg_buffer
.retain(|skgm| !key_gen_messages.contains(skgm));
for SignedKeyGenMsg(epoch, s_id, kg_msg, sig) in key_gen_messages {
if epoch < self.start_epoch {
info!("Obsolete key generation message: {:?}.", kg_msg);
continue;
}
if !self.verify_signature(&s_id, &sig, &kg_msg)? {
info!(
"Invalid signature in {:?}'s batch from {:?} for: {:?}.",
id, s_id, kg_msg
);
let fault_kind = FaultKind::InvalidKeyGenMessageSignature;
step.fault_log.append(id.clone(), fault_kind);
continue;
}
step.extend(match kg_msg {
KeyGenMessage::Part(part) => self.handle_part(&s_id, part)?,
KeyGenMessage::Ack(ack) => self.handle_ack(&s_id, ack)?.into(),
});
}
}
if let Some(kgs) = self.take_ready_key_gen() {
// If DKG completed, apply the change, restart Honey Badger, and inform the user.
debug!("{:?} DKG for {:?} complete!", self.our_id(), kgs.change);
self.netinfo = kgs.key_gen.into_network_info();
self.restart_honey_badger(batch.epoch + 1);
batch.set_change(ChangeState::Complete(kgs.change), &self.netinfo);
} else if let Some(change) = self.vote_counter.compute_winner().cloned() {
// If there is a new change, restart DKG. Inform the user about the current change.
step.extend(self.update_key_gen(batch.epoch + 1, &change)?);
batch.set_change(ChangeState::InProgress(change), &self.netinfo);
}
step.output.push_back(batch);
}
// If `start_epoch` changed, we can now handle some queued messages.
if start_epoch < self.start_epoch {
let queue = mem::replace(&mut self.incoming_queue, Vec::new());
for (sender_id, msg) in queue {
step.extend(self.handle_message(&sender_id, msg)?);
}
}
Ok(step)
}
/// If the winner of the vote has changed, restarts Key Generation for the set of nodes implied
/// by the current change.
pub(super) fn update_key_gen(
&mut self,
epoch: u64,
change: &Change<NodeUid>,
) -> Result<Step<C, NodeUid>> {
if self.key_gen_state.as_ref().map(|kgs| &kgs.change) == Some(change) {
return Ok(Step::default()); // The change is the same as before. Continue DKG as is.
}
debug!("{:?} Restarting DKG for {:?}.", self.our_id(), change);
// Use the existing key shares - with the change applied - as keys for DKG.
let mut pub_keys = self.netinfo.public_key_map().clone();
if match *change {
Change::Remove(ref id) => pub_keys.remove(id).is_none(),
Change::Add(ref id, ref pk) => pub_keys.insert(id.clone(), pk.clone()).is_some(),
} {
info!("{:?} No-op change: {:?}", self.our_id(), change);
}
self.restart_honey_badger(epoch);
// TODO: This needs to be the same as `num_faulty` will be in the _new_
// `NetworkInfo` if the change goes through. It would be safer to deduplicate.
let threshold = (pub_keys.len() - 1) / 3;
let sk = self.netinfo.secret_key().clone();
let our_uid = self.our_id().clone();
let (key_gen, part) = SyncKeyGen::new(our_uid, sk, pub_keys, threshold);
self.key_gen_state = Some(KeyGenState::new(key_gen, change.clone()));
if let Some(part) = part {
self.send_transaction(KeyGenMessage::Part(part))
} else {
Ok(Step::default())
}
}
/// Starts a new `HoneyBadger` instance and resets the vote counter.
fn restart_honey_badger(&mut self, epoch: u64) {
self.start_epoch = epoch;
self.key_gen_msg_buffer.retain(|kg_msg| kg_msg.0 >= epoch);
let netinfo = Arc::new(self.netinfo.clone());
let counter = VoteCounter::new(netinfo.clone(), epoch);
mem::replace(&mut self.vote_counter, counter);
self.honey_badger = HoneyBadger::builder(netinfo)
.max_future_epochs(self.max_future_epochs)
.build();
}
/// Handles a `Part` message that was output by Honey Badger.
fn handle_part(&mut self, sender_id: &NodeUid, part: Part) -> Result<Step<C, NodeUid>> {
let handle = |kgs: &mut KeyGenState<NodeUid>| kgs.key_gen.handle_part(&sender_id, part);
match self.key_gen_state.as_mut().and_then(handle) {
Some(PartOutcome::Valid(ack)) => self.send_transaction(KeyGenMessage::Ack(ack)),
Some(PartOutcome::Invalid(fault_log)) => Ok(fault_log.into()),
None => Ok(Step::default()),
}
}
/// Handles an `Ack` message that was output by Honey Badger.
fn handle_ack(&mut self, sender_id: &NodeUid, ack: Ack) -> Result<FaultLog<NodeUid>> {
if let Some(kgs) = self.key_gen_state.as_mut() {
Ok(kgs.key_gen.handle_ack(sender_id, ack))
} else {
Ok(FaultLog::new())
}
}
/// Signs and sends a `KeyGenMessage` and also tries to commit it.
fn send_transaction(&mut self, kg_msg: KeyGenMessage) -> Result<Step<C, NodeUid>> {
let ser =
bincode::serialize(&kg_msg).map_err(|err| ErrorKind::SendTransactionBincode(*err))?;
let sig = Box::new(self.netinfo.secret_key().sign(ser));
if self.netinfo.is_validator() {
let our_uid = self.netinfo.our_uid().clone();
let signed_msg =
SignedKeyGenMsg(self.start_epoch, our_uid, kg_msg.clone(), *sig.clone());
self.key_gen_msg_buffer.push(signed_msg);
}
let msg = Message::KeyGen(self.start_epoch, kg_msg, sig);
Ok(Target::All.message(msg).into())
}
/// If the current Key Generation process is ready, returns the `KeyGenState`.
///
/// We require the minimum number of completed proposals (`SyncKeyGen::is_ready`) and if a new
/// node is joining, we require in addition that the new node's proposal is complete. That way
/// the new node knows that it's key is secret, without having to trust any number of nodes.
fn take_ready_key_gen(&mut self) -> Option<KeyGenState<NodeUid>> {
if self
.key_gen_state
.as_ref()
.map_or(false, KeyGenState::is_ready)
{
self.key_gen_state.take()
} else {
None
}
}
/// Returns `true` if the signature of `kg_msg` by the node with the specified ID is valid.
/// Returns an error if the payload fails to serialize.
///
/// This accepts signatures from both validators and the currently joining candidate, if any.
fn verify_signature(
&self,
node_id: &NodeUid,
sig: &Signature,
kg_msg: &KeyGenMessage,
) -> Result<bool> {
let ser =
bincode::serialize(kg_msg).map_err(|err| ErrorKind::VerifySignatureBincode(*err))?;
let get_candidate_key = || {
self.key_gen_state
.as_ref()
.and_then(|kgs| kgs.candidate_key(node_id))
};
let pk_opt = self.netinfo.public_key(node_id).or_else(get_candidate_key);
Ok(pk_opt.map_or(false, |pk| pk.verify(&sig, ser)))
}
}

460
src/dynamic_honey_badger/mod.rs
View File

@ -55,30 +55,33 @@
//! and replaced by a new one with the new set of participants. If a different change wins a
//! vote before that happens, key generation resets again, and is attempted for the new change.
mod batch;
mod builder;
mod change;
mod dynamic_honey_badger;
mod error;
mod votes;
use crypto::{PublicKey, PublicKeySet, Signature};
use rand::Rand;
use std::collections::BTreeMap;
use std::fmt::Debug;
use std::hash::Hash;
use std::mem;
use std::sync::Arc;
use bincode;
use crypto::{PublicKey, PublicKeySet, Signature};
use serde::{Deserialize, Serialize};
use self::votes::{SignedVote, VoteCounter};
use honey_badger::Message as HbMessage;
use messaging;
use sync_key_gen::{Ack, Part, SyncKeyGen};
use fault_log::{Fault, FaultKind, FaultLog};
use honey_badger::{self, HoneyBadger, Message as HbMessage};
use messaging::{self, DistAlgorithm, NetworkInfo, Target};
use sync_key_gen::{Ack, Part, PartOutcome, SyncKeyGen};
pub use self::batch::Batch;
pub use self::builder::DynamicHoneyBadgerBuilder;
pub use self::change::{Change, ChangeState};
pub use self::dynamic_honey_badger::DynamicHoneyBadger;
pub use self::error::{Error, ErrorKind, Result};
pub type Step<C, NodeUid> = messaging::Step<DynamicHoneyBadger<C, NodeUid>>;
mod batch;
mod builder;
mod change;
mod error;
mod votes;
/// The user input for `DynamicHoneyBadger`.
#[derive(Clone, Debug)]
@ -89,6 +92,421 @@ pub enum Input<C, NodeUid> {
Change(Change<NodeUid>),
}
/// A Honey Badger instance that can handle adding and removing nodes.
#[derive(Debug)]
pub struct DynamicHoneyBadger<C, NodeUid: Rand> {
/// Shared network data.
netinfo: NetworkInfo<NodeUid>,
/// The maximum number of future epochs for which we handle messages simultaneously.
max_future_epochs: usize,
/// The first epoch after the latest node change.
start_epoch: u64,
/// The buffer and counter for the pending and committed change votes.
vote_counter: VoteCounter<NodeUid>,
/// Pending node transactions that we will propose in the next epoch.
key_gen_msg_buffer: Vec<SignedKeyGenMsg<NodeUid>>,
/// The `HoneyBadger` instance with the current set of nodes.
honey_badger: HoneyBadger<InternalContrib<C, NodeUid>, NodeUid>,
/// The current key generation process, and the change it applies to.
key_gen_state: Option<KeyGenState<NodeUid>>,
/// A queue for messages from future epochs that cannot be handled yet.
incoming_queue: Vec<(NodeUid, Message<NodeUid>)>,
}
pub type Step<C, NodeUid> = messaging::Step<DynamicHoneyBadger<C, NodeUid>>;
impl<C, NodeUid> DistAlgorithm for DynamicHoneyBadger<C, NodeUid>
where
C: Eq + Serialize + for<'r> Deserialize<'r> + Debug + Hash,
NodeUid: Eq + Ord + Clone + Serialize + for<'r> Deserialize<'r> + Debug + Hash + Rand,
{
type NodeUid = NodeUid;
type Input = Input<C, NodeUid>;
type Output = Batch<C, NodeUid>;
type Message = Message<NodeUid>;
type Error = Error;
fn input(&mut self, input: Self::Input) -> Result<Step<C, NodeUid>> {
// User contributions are forwarded to `HoneyBadger` right away. Votes are signed and
// broadcast.
match input {
Input::User(contrib) => self.propose(contrib),
Input::Change(change) => self.vote_for(change),
}
}
fn handle_message(
&mut self,
sender_id: &NodeUid,
message: Self::Message,
) -> Result<Step<C, NodeUid>> {
let epoch = message.start_epoch();
if epoch < self.start_epoch {
// Obsolete message.
Ok(Step::default())
} else if epoch > self.start_epoch {
// Message cannot be handled yet. Save it for later.
let entry = (sender_id.clone(), message);
self.incoming_queue.push(entry);
Ok(Step::default())
} else {
match message {
Message::HoneyBadger(_, hb_msg) => {
self.handle_honey_badger_message(sender_id, hb_msg)
}
Message::KeyGen(_, kg_msg, sig) => self
.handle_key_gen_message(sender_id, kg_msg, *sig)
.map(FaultLog::into),
Message::SignedVote(signed_vote) => self
.vote_counter
.add_pending_vote(sender_id, signed_vote)
.map(FaultLog::into),
}
}
}
fn terminated(&self) -> bool {
false
}
fn our_id(&self) -> &NodeUid {
self.netinfo.our_uid()
}
}
impl<C, NodeUid> DynamicHoneyBadger<C, NodeUid>
where
C: Eq + Serialize + for<'r> Deserialize<'r> + Debug + Hash,
NodeUid: Eq + Ord + Clone + Debug + Serialize + for<'r> Deserialize<'r> + Hash + Rand,
{
/// Returns a new `DynamicHoneyBadgerBuilder`.
pub fn builder() -> DynamicHoneyBadgerBuilder<C, NodeUid> {
DynamicHoneyBadgerBuilder::new()
}
/// Returns `true` if input for the current epoch has already been provided.
pub fn has_input(&self) -> bool {
self.honey_badger.has_input()
}
/// Proposes a contribution in the current epoch.
pub fn propose(&mut self, contrib: C) -> Result<Step<C, NodeUid>> {
let step = self
.honey_badger
.input(InternalContrib {
contrib,
key_gen_messages: self.key_gen_msg_buffer.clone(),
votes: self.vote_counter.pending_votes().cloned().collect(),
})
.map_err(ErrorKind::ProposeHoneyBadger)?;
self.process_output(step)
}
/// Cast a vote to change the set of validators.
pub fn vote_for(&mut self, change: Change<NodeUid>) -> Result<Step<C, NodeUid>> {
if !self.netinfo.is_validator() {
return Ok(Step::default()); // TODO: Return an error?
}
let signed_vote = self.vote_counter.sign_vote_for(change)?.clone();
let msg = Message::SignedVote(signed_vote);
Ok(Target::All.message(msg).into())
}
/// Returns the information about the node IDs in the network, and the cryptographic keys.
pub fn netinfo(&self) -> &NetworkInfo<NodeUid> {
&self.netinfo
}
/// Returns `true` if we should make our contribution for the next epoch, even if we don't have
/// content ourselves, to avoid stalling the network.
///
/// By proposing only if this returns `true`, you can prevent an adversary from making the
/// network output empty baches indefinitely, but it also means that the network won't advance
/// if fewer than _f + 1_ nodes have pending contributions.
pub fn should_propose(&self) -> bool {
if self.has_input() {
return false; // We have already proposed.
}
if self.honey_badger.received_proposals() > self.netinfo.num_faulty() {
return true; // At least one correct node wants to move on to the next epoch.
}
let is_our_vote = |signed_vote: &SignedVote<_>| signed_vote.voter() == self.our_id();
if self.vote_counter.pending_votes().any(is_our_vote) {
return true; // We have pending input to vote for a validator change.
}
let kgs = match self.key_gen_state {
None => return false, // No ongoing key generation.
Some(ref kgs) => kgs,
};
// If either we or the candidate have a pending key gen message, we should propose.
let ours_or_candidates = |msg: &SignedKeyGenMsg<_>| {
msg.1 == *self.our_id() || Some(&msg.1) == kgs.change.candidate()
};
self.key_gen_msg_buffer.iter().any(ours_or_candidates)
}
/// Handles a message for the `HoneyBadger` instance.
fn handle_honey_badger_message(
&mut self,
sender_id: &NodeUid,
message: HbMessage<NodeUid>,
) -> Result<Step<C, NodeUid>> {
if !self.netinfo.is_node_validator(sender_id) {
info!("Unknown sender {:?} of message {:?}", sender_id, message);
return Err(ErrorKind::UnknownSender.into());
}
// Handle the message.
let step = self
.honey_badger
.handle_message(sender_id, message)
.map_err(ErrorKind::HandleHoneyBadgerMessageHoneyBadger)?;
self.process_output(step)
}
/// Handles a vote or key generation message and tries to commit it as a transaction. These
/// messages are only handled once they appear in a batch output from Honey Badger.
fn handle_key_gen_message(
&mut self,
sender_id: &NodeUid,
kg_msg: KeyGenMessage,
sig: Signature,
) -> Result<FaultLog<NodeUid>> {
if !self.verify_signature(sender_id, &sig, &kg_msg)? {
info!("Invalid signature from {:?} for: {:?}.", sender_id, kg_msg);
let fault_kind = FaultKind::InvalidKeyGenMessageSignature;
return Ok(Fault::new(sender_id.clone(), fault_kind).into());
}
let kgs = match self.key_gen_state {
Some(ref mut kgs) => kgs,
None => {
info!(
"Unexpected key gen message from {:?}: {:?}.",
sender_id, kg_msg
);
return Ok(Fault::new(sender_id.clone(), FaultKind::UnexpectedKeyGenMessage).into());
}
};
// If the joining node is correct, it will send at most (N + 1)² + 1 key generation
// messages.
if Some(sender_id) == kgs.change.candidate() {
let n = self.netinfo.num_nodes() + 1;
if kgs.candidate_msg_count > n * n {
info!(
"Too many key gen messages from candidate {:?}: {:?}.",
sender_id, kg_msg
);
let fault_kind = FaultKind::TooManyCandidateKeyGenMessages;
return Ok(Fault::new(sender_id.clone(), fault_kind).into());
}
kgs.candidate_msg_count += 1;
}
let tx = SignedKeyGenMsg(self.start_epoch, sender_id.clone(), kg_msg, sig);
self.key_gen_msg_buffer.push(tx);
Ok(FaultLog::default())
}
/// Processes all pending batches output by Honey Badger.
fn process_output(
&mut self,
hb_step: honey_badger::Step<InternalContrib<C, NodeUid>, NodeUid>,
) -> Result<Step<C, NodeUid>> {
let mut step: Step<C, NodeUid> = Step::default();
let start_epoch = self.start_epoch;
let output = step.extend_with(hb_step, |hb_msg| Message::HoneyBadger(start_epoch, hb_msg));
for hb_batch in output {
// Create the batch we output ourselves. It will contain the _user_ transactions of
// `hb_batch`, and the current change state.
let mut batch = Batch::new(hb_batch.epoch + self.start_epoch);
// Add the user transactions to `batch` and handle votes and DKG messages.
for (id, int_contrib) in hb_batch.contributions {
let InternalContrib {
votes,
key_gen_messages,
contrib,
} = int_contrib;
step.fault_log
.extend(self.vote_counter.add_committed_votes(&id, votes)?);
batch.contributions.insert(id.clone(), contrib);
self.key_gen_msg_buffer
.retain(|skgm| !key_gen_messages.contains(skgm));
for SignedKeyGenMsg(epoch, s_id, kg_msg, sig) in key_gen_messages {
if epoch < self.start_epoch {
info!("Obsolete key generation message: {:?}.", kg_msg);
continue;
}
if !self.verify_signature(&s_id, &sig, &kg_msg)? {
info!(
"Invalid signature in {:?}'s batch from {:?} for: {:?}.",
id, s_id, kg_msg
);
let fault_kind = FaultKind::InvalidKeyGenMessageSignature;
step.fault_log.append(id.clone(), fault_kind);
continue;
}
step.extend(match kg_msg {
KeyGenMessage::Part(part) => self.handle_part(&s_id, part)?,
KeyGenMessage::Ack(ack) => self.handle_ack(&s_id, ack)?.into(),
});
}
}
if let Some(kgs) = self.take_ready_key_gen() {
// If DKG completed, apply the change, restart Honey Badger, and inform the user.
debug!("{:?} DKG for {:?} complete!", self.our_id(), kgs.change);
self.netinfo = kgs.key_gen.into_network_info();
self.restart_honey_badger(batch.epoch + 1);
batch.set_change(ChangeState::Complete(kgs.change), &self.netinfo);
} else if let Some(change) = self.vote_counter.compute_winner().cloned() {
// If there is a new change, restart DKG. Inform the user about the current change.
step.extend(self.update_key_gen(batch.epoch + 1, &change)?);
batch.set_change(ChangeState::InProgress(change), &self.netinfo);
}
step.output.push_back(batch);
}
// If `start_epoch` changed, we can now handle some queued messages.
if start_epoch < self.start_epoch {
let queue = mem::replace(&mut self.incoming_queue, Vec::new());
for (sender_id, msg) in queue {
step.extend(self.handle_message(&sender_id, msg)?);
}
}
Ok(step)
}
/// If the winner of the vote has changed, restarts Key Generation for the set of nodes implied
/// by the current change.
fn update_key_gen(&mut self, epoch: u64, change: &Change<NodeUid>) -> Result<Step<C, NodeUid>> {
if self.key_gen_state.as_ref().map(|kgs| &kgs.change) == Some(change) {
return Ok(Step::default()); // The change is the same as before. Continue DKG as is.
}
debug!("{:?} Restarting DKG for {:?}.", self.our_id(), change);
// Use the existing key shares - with the change applied - as keys for DKG.
let mut pub_keys = self.netinfo.public_key_map().clone();
if match *change {
Change::Remove(ref id) => pub_keys.remove(id).is_none(),
Change::Add(ref id, ref pk) => pub_keys.insert(id.clone(), pk.clone()).is_some(),
} {
info!("{:?} No-op change: {:?}", self.our_id(), change);
}
self.restart_honey_badger(epoch);
// TODO: This needs to be the same as `num_faulty` will be in the _new_
// `NetworkInfo` if the change goes through. It would be safer to deduplicate.
let threshold = (pub_keys.len() - 1) / 3;
let sk = self.netinfo.secret_key().clone();
let our_uid = self.our_id().clone();
let (key_gen, part) = SyncKeyGen::new(our_uid, sk, pub_keys, threshold);
self.key_gen_state = Some(KeyGenState::new(key_gen, change.clone()));
if let Some(part) = part {
self.send_transaction(KeyGenMessage::Part(part))
} else {
Ok(Step::default())
}
}
/// Starts a new `HoneyBadger` instance and resets the vote counter.
fn restart_honey_badger(&mut self, epoch: u64) {
self.start_epoch = epoch;
self.key_gen_msg_buffer.retain(|kg_msg| kg_msg.0 >= epoch);
let netinfo = Arc::new(self.netinfo.clone());
let counter = VoteCounter::new(netinfo.clone(), epoch);
mem::replace(&mut self.vote_counter, counter);
self.honey_badger = HoneyBadger::builder(netinfo)
.max_future_epochs(self.max_future_epochs)
.build();
}
/// Handles a `Part` message that was output by Honey Badger.
fn handle_part(&mut self, sender_id: &NodeUid, part: Part) -> Result<Step<C, NodeUid>> {
let handle = |kgs: &mut KeyGenState<NodeUid>| kgs.key_gen.handle_part(&sender_id, part);
match self.key_gen_state.as_mut().and_then(handle) {
Some(PartOutcome::Valid(ack)) => self.send_transaction(KeyGenMessage::Ack(ack)),
Some(PartOutcome::Invalid(fault_log)) => Ok(fault_log.into()),
None => Ok(Step::default()),
}
}
/// Handles an `Ack` message that was output by Honey Badger.
fn handle_ack(&mut self, sender_id: &NodeUid, ack: Ack) -> Result<FaultLog<NodeUid>> {
if let Some(kgs) = self.key_gen_state.as_mut() {
Ok(kgs.key_gen.handle_ack(sender_id, ack))
} else {
Ok(FaultLog::new())
}
}
/// Signs and sends a `KeyGenMessage` and also tries to commit it.
fn send_transaction(&mut self, kg_msg: KeyGenMessage) -> Result<Step<C, NodeUid>> {
let ser =
bincode::serialize(&kg_msg).map_err(|err| ErrorKind::SendTransactionBincode(*err))?;
let sig = Box::new(self.netinfo.secret_key().sign(ser));
if self.netinfo.is_validator() {
let our_uid = self.netinfo.our_uid().clone();
let signed_msg =
SignedKeyGenMsg(self.start_epoch, our_uid, kg_msg.clone(), *sig.clone());
self.key_gen_msg_buffer.push(signed_msg);
}
let msg = Message::KeyGen(self.start_epoch, kg_msg, sig);
Ok(Target::All.message(msg).into())
}
/// If the current Key Generation process is ready, returns the `KeyGenState`.
///
/// We require the minimum number of completed proposals (`SyncKeyGen::is_ready`) and if a new
/// node is joining, we require in addition that the new node's proposal is complete. That way
/// the new node knows that it's key is secret, without having to trust any number of nodes.
fn take_ready_key_gen(&mut self) -> Option<KeyGenState<NodeUid>> {
if self
.key_gen_state
.as_ref()
.map_or(false, KeyGenState::is_ready)
{
self.key_gen_state.take()
} else {
None
}
}
/// Returns `true` if the signature of `kg_msg` by the node with the specified ID is valid.
/// Returns an error if the payload fails to serialize.
///
/// This accepts signatures from both validators and the currently joining candidate, if any.
fn verify_signature(
&self,
node_id: &NodeUid,
sig: &Signature,
kg_msg: &KeyGenMessage,
) -> Result<bool> {
let ser =
bincode::serialize(kg_msg).map_err(|err| ErrorKind::VerifySignatureBincode(*err))?;
let get_candidate_key = || {
self.key_gen_state
.as_ref()
.and_then(|kgs| kgs.candidate_key(node_id))
};
let pk_opt = self.netinfo.public_key(node_id).or_else(get_candidate_key);
Ok(pk_opt.map_or(false, |pk| pk.verify(&sig, ser)))
}
}
/// The contribution for the internal `HoneyBadger` instance: this includes a user-defined
/// application-level contribution as well as internal signed messages.
#[derive(Clone, Eq, PartialEq, Debug, Serialize, Deserialize, Hash)]
struct InternalContrib<C, NodeUid> {
/// A user-defined contribution.
contrib: C,
/// Key generation messages that get committed via Honey Badger to communicate synchronously.
key_gen_messages: Vec<SignedKeyGenMsg<NodeUid>>,
/// Signed votes for validator set changes.
votes: Vec<SignedVote<NodeUid>>,
}
/// A signed internal message.
#[derive(Eq, PartialEq, Debug, Serialize, Deserialize, Hash, Clone)]
struct SignedKeyGenMsg<NodeUid>(u64, NodeUid, KeyGenMessage, Signature);
/// An internal message containing a vote for adding or removing a validator, or a message for key
/// generation. It gets committed via Honey Badger and is only handled after it has been output in
/// a batch, so that all nodes see these messages in the same order.
@ -180,19 +598,3 @@ impl<NodeUid: Ord + Clone + Debug> KeyGenState<NodeUid> {
}
}
}
/// The contribution for the internal `HoneyBadger` instance: this includes a user-defined
/// application-level contribution as well as internal signed messages.
#[derive(Clone, Eq, PartialEq, Debug, Serialize, Deserialize, Hash)]
struct InternalContrib<C, NodeUid> {
/// A user-defined contribution.
contrib: C,
/// Key generation messages that get committed via Honey Badger to communicate synchronously.
key_gen_messages: Vec<SignedKeyGenMsg<NodeUid>>,
/// Signed votes for validator set changes.
votes: Vec<SignedVote<NodeUid>>,
}
/// A signed internal message.
#[derive(Eq, PartialEq, Debug, Serialize, Deserialize, Hash, Clone)]
struct SignedKeyGenMsg<NodeUid>(u64, NodeUid, KeyGenMessage, Signature);

13
src/dynamic_honey_badger/votes.rs
View File

@ -67,10 +67,11 @@ where
sender_id: &NodeUid,
signed_vote: SignedVote<NodeUid>,
) -> Result<FaultLog<NodeUid>> {
if signed_vote.vote.era != self.era || self
.pending
.get(&signed_vote.voter)
.map_or(false, |sv| sv.vote.num >= signed_vote.vote.num)
if signed_vote.vote.era != self.era
|| self
.pending
.get(&signed_vote.voter)
.map_or(false, |sv| sv.vote.num >= signed_vote.vote.num)
{
return Ok(FaultLog::new()); // The vote is obsolete or already exists.
}
@ -149,8 +150,8 @@ where
/// Returns `true` if the signature is valid.
fn validate(&self, signed_vote: &SignedVote<NodeUid>) -> Result<bool> {
let ser_vote = bincode::serialize(&signed_vote.vote)
.map_err(|err| ErrorKind::ValidateBincode(*err))?;
let ser_vote =
bincode::serialize(&signed_vote.vote).map_err(|err| ErrorKind::ValidateBincode(*err))?;
let pk_opt = self.netinfo.public_key(&signed_vote.voter);
Ok(pk_opt.map_or(false, |pk| pk.verify(&signed_vote.sig, ser_vote)))
}

3
src/honey_badger/honey_badger.rs
View File

@ -270,7 +270,8 @@ where
step.fault_log.append(proposer_id, fault_kind);
None
}
}).collect();
})
.collect();
let batch = Batch {
epoch: self.epoch,
contributions,

3
tests/dynamic_honey_badger.rs
View File

@ -81,7 +81,8 @@ where
// If there's only one node, it will immediately output on input. Make sure we
// first process all incoming messages before providing input again.
&& (network.nodes.len() > 2 || node.queue.is_empty())
}).map(|(id, _)| *id)
})
.map(|(id, _)| *id)
.collect();
if let Some(id) = rng.choose(&input_ids) {
let queue = queues.get_mut(id).unwrap();

3
tests/honey_badger.rs
View File

@ -175,7 +175,8 @@ where
epoch,
contributions,
}| (epoch, contributions),
).collect();
)
.collect();
if expected.is_none() {
expected = Some(outputs);
} else if let Some(expected) = &expected {

6
tests/sync_key_gen.rs
View File

@ -31,7 +31,8 @@ fn test_sync_key_gen_with(threshold: usize, node_num: usize) {
let (sync_key_gen, proposal) = SyncKeyGen::new(id, sk, pub_keys.clone(), threshold);
nodes.push(sync_key_gen);
proposal
}).collect();
})
.collect();
// Handle the first `threshold + 1` proposals. Those should suffice for key generation.
let mut acks = Vec::new();
@ -71,7 +72,8 @@ fn test_sync_key_gen_with(threshold: usize, node_num: usize) {
let sig = sk.sign(msg);
assert!(pks.public_key_share(idx).verify(&sig, msg));
(idx, sig)
}).collect();
})
.collect();
let sig = pub_key_set
.combine_signatures(sig_shares.iter().take(threshold + 1))
.expect("signature shares match");