mirror of https://github.com/poanetwork/hbbft.git
722 lines
27 KiB
Rust
722 lines
27 KiB
Rust
use std::collections::BTreeMap;
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use std::collections::BTreeSet;
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use std::sync::Arc;
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use std::{fmt, result};
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use byteorder::{BigEndian, ByteOrder};
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use hex_fmt::{HexFmt, HexList};
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use log::{debug, warn};
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use rand::Rng;
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use reed_solomon_erasure as rse;
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use reed_solomon_erasure::{galois_8::Field as Field8, ReedSolomon};
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use super::merkle::{Digest, MerkleTree, Proof};
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use super::message::HexProof;
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use super::{Error, FaultKind, Message, Result};
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use crate::fault_log::Fault;
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use crate::{ConsensusProtocol, NodeIdT, Target, ValidatorSet};
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type RseResult<T> = result::Result<T, rse::Error>;
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/// Broadcast algorithm instance.
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#[derive(Debug)]
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pub struct Broadcast<N> {
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/// Our ID.
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// TODO: Make optional for observers?
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our_id: N,
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/// The set of validator IDs.
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val_set: Arc<ValidatorSet<N>>,
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/// The ID of the sending node.
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proposer_id: N,
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/// The Reed-Solomon erasure coding configuration.
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coding: Coding,
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/// If we are the proposer: whether we have already sent the `Value` messages with the shards.
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value_sent: bool,
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/// Whether we have already sent `Echo` to all nodes who haven't sent `CanDecode`.
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echo_sent: bool,
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/// Whether we have already multicast `Ready`.
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ready_sent: bool,
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/// Whether we have already sent `EchoHash` to the right nodes.
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echo_hash_sent: bool,
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/// Whether we have already sent `CanDecode` for the given hash.
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can_decode_sent: BTreeSet<Digest>,
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/// Whether we have already output a value.
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decided: bool,
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/// Number of faulty nodes to optimize performance for.
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// TODO: Make this configurable: Allow numbers between 0 and N/3?
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fault_estimate: usize,
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/// The hashes and proofs we have received via `Echo` and `EchoHash` messages, by sender ID.
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echos: BTreeMap<N, EchoContent>,
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/// The hashes we have received from nodes via `CanDecode` messages, by hash.
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/// A node can receive conflicting `CanDecode`s from the same node.
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can_decodes: BTreeMap<Digest, BTreeSet<N>>,
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/// The root hashes we received via `Ready` messages, by sender ID.
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readys: BTreeMap<N, Vec<u8>>,
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}
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/// A `Broadcast` step, containing at most one output.
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pub type Step<N> = crate::CpStep<Broadcast<N>>;
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impl<N: NodeIdT> ConsensusProtocol for Broadcast<N> {
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type NodeId = N;
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type Input = Vec<u8>;
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type Output = Self::Input;
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type Message = Message;
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type Error = Error;
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type FaultKind = FaultKind;
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fn handle_input<R: Rng>(&mut self, input: Self::Input, _rng: &mut R) -> Result<Step<N>> {
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self.broadcast(input)
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}
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fn handle_message<R: Rng>(
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&mut self,
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sender_id: &Self::NodeId,
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message: Message,
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_rng: &mut R,
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) -> Result<Step<N>> {
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self.handle_message(sender_id, message)
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}
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fn terminated(&self) -> bool {
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self.decided
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}
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fn our_id(&self) -> &N {
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&self.our_id
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}
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}
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impl<N: NodeIdT> Broadcast<N> {
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/// Creates a new broadcast instance to be used by node `our_id` which expects a value proposal
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/// from node `proposer_id`.
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pub fn new<V>(our_id: N, val_set: V, proposer_id: N) -> Result<Self>
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where
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V: Into<Arc<ValidatorSet<N>>>,
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{
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let val_set: Arc<ValidatorSet<N>> = val_set.into();
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let parity_shard_num = 2 * val_set.num_faulty();
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let data_shard_num = val_set.num() - parity_shard_num;
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let coding =
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Coding::new(data_shard_num, parity_shard_num).map_err(|_| Error::InvalidNodeCount)?;
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let fault_estimate = val_set.num_faulty();
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Ok(Broadcast {
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our_id,
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val_set,
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proposer_id,
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coding,
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value_sent: false,
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echo_sent: false,
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ready_sent: false,
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echo_hash_sent: false,
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can_decode_sent: BTreeSet::new(),
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decided: false,
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fault_estimate,
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echos: BTreeMap::new(),
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can_decodes: BTreeMap::new(),
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readys: BTreeMap::new(),
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})
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}
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/// Initiates the broadcast. This must only be called in the proposer node.
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pub fn broadcast(&mut self, input: Vec<u8>) -> Result<Step<N>> {
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if *self.our_id() != self.proposer_id {
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return Err(Error::InstanceCannotPropose);
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}
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if self.value_sent {
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return Err(Error::MultipleInputs);
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}
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self.value_sent = true;
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// Split the value into chunks/shards, encode them with erasure codes.
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// Assemble a Merkle tree from data and parity shards. Take all proofs
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// from this tree and send them, each to its own node.
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let (proof, step) = self.send_shards(input)?;
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let our_id = &self.our_id().clone();
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Ok(step.join(self.handle_value(our_id, proof)?))
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}
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/// Handles a message received from `sender_id`.
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///
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/// This must be called with every message we receive from another node.
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pub fn handle_message(&mut self, sender_id: &N, message: Message) -> Result<Step<N>> {
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if !self.val_set.contains(sender_id) {
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return Err(Error::UnknownSender);
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}
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match message {
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Message::Value(p) => self.handle_value(sender_id, p),
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Message::Echo(p) => self.handle_echo(sender_id, p),
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Message::Ready(ref hash) => self.handle_ready(sender_id, hash),
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Message::CanDecode(ref hash) => self.handle_can_decode(sender_id, hash),
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Message::EchoHash(ref hash) => self.handle_echo_hash(sender_id, hash),
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}
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}
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/// Returns the proposer's node ID.
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pub fn proposer_id(&self) -> &N {
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&self.proposer_id
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}
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/// Returns the set of all validator IDs.
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pub fn validator_set(&self) -> &Arc<ValidatorSet<N>> {
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&self.val_set
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}
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/// Breaks the input value into shards of equal length and encodes them --
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/// and some extra parity shards -- with a Reed-Solomon erasure coding
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/// scheme. The returned value contains the shard assigned to this
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/// node. That shard doesn't need to be sent anywhere. It gets recorded in
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/// the broadcast instance.
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fn send_shards(&mut self, mut value: Vec<u8>) -> Result<(Proof<Vec<u8>>, Step<N>)> {
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let data_shard_num = self.coding.data_shard_count();
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let parity_shard_num = self.coding.parity_shard_count();
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// Insert the length of `v` so it can be decoded without the padding.
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let payload_len = value.len() as u32;
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value.splice(0..0, 0..4); // Insert four bytes at the beginning.
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BigEndian::write_u32(&mut value[..4], payload_len); // Write the size.
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let value_len = value.len(); // This is at least 4 now, due to the payload length.
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// Size of a Merkle tree leaf value: the value size divided by the number of data shards,
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// and rounded up, so that the full value always fits in the data shards. Always at least 1.
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let shard_len = (value_len + data_shard_num - 1) / data_shard_num;
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// Pad the last data shard with zeros. Fill the parity shards with zeros.
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value.resize(shard_len * (data_shard_num + parity_shard_num), 0);
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// Divide the vector into chunks/shards.
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let shards_iter = value.chunks_mut(shard_len);
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// Convert the iterator over slices into a vector of slices.
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let mut shards: Vec<&mut [u8]> = shards_iter.collect();
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// Construct the parity chunks/shards. This only fails if a shard is empty or the shards
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// have different sizes. Our shards all have size `shard_len`, which is at least 1.
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self.coding.encode(&mut shards).expect("wrong shard size");
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debug!(
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"{}: Value: {} bytes, {} per shard. Shards: {:0.10}",
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self,
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value_len,
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shard_len,
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HexList(&shards)
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);
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// Create a Merkle tree from the shards.
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let mtree = MerkleTree::from_vec(shards.into_iter().map(|shard| shard.to_vec()).collect());
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// Default result in case of `proof` error.
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let mut result = Err(Error::ProofConstructionFailed);
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assert_eq!(self.val_set.num(), mtree.values().len());
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let mut step = Step::default();
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// Send each proof to a node.
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for (id, index) in self.val_set.all_indices() {
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let proof = mtree.proof(*index).ok_or(Error::ProofConstructionFailed)?;
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if *id == *self.our_id() {
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// The proof is addressed to this node.
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result = Ok(proof);
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} else {
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// Rest of the proofs are sent to remote nodes.
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let msg = Target::node(id.clone()).message(Message::Value(proof));
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step.messages.push(msg);
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}
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}
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result.map(|proof| (proof, step))
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}
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/// Handles a received echo and verifies the proof it contains.
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fn handle_value(&mut self, sender_id: &N, p: Proof<Vec<u8>>) -> Result<Step<N>> {
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// If the sender is not the proposer or if this is not the first `Value`, ignore.
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if *sender_id != self.proposer_id {
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let fault_kind = FaultKind::ReceivedValueFromNonProposer;
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return Ok(Fault::new(sender_id.clone(), fault_kind).into());
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}
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match self.echos.get(self.our_id()) {
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// Multiple values from proposer.
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Some(val) if val.hash() != p.root_hash() => {
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return Ok(Fault::new(sender_id.clone(), FaultKind::MultipleValues).into())
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}
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// Already received proof.
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Some(EchoContent::Full(proof)) if *proof == p => {
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warn!(
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"Node {:?} received Value({:?}) multiple times from {:?}.",
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self.our_id(),
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HexProof(&p),
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sender_id
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);
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return Ok(Step::default());
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}
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_ => (),
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};
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// If the proof is invalid, log the faulty node behavior and ignore.
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if !self.validate_proof(&p, &self.our_id()) {
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return Ok(Fault::new(sender_id.clone(), FaultKind::InvalidProof).into());
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}
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// Send the proof in an `Echo` message to left nodes
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// and `EchoHash` message to right nodes and handle the response.
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let echo_hash_steps = self.send_echo_hash(p.root_hash())?;
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let echo_steps = self.send_echo_left(p)?;
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Ok(echo_steps.join(echo_hash_steps))
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}
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/// Handles a received `Echo` message.
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fn handle_echo(&mut self, sender_id: &N, p: Proof<Vec<u8>>) -> Result<Step<N>> {
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// If the sender has already sent `Echo`, ignore.
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if let Some(EchoContent::Full(old_p)) = self.echos.get(sender_id) {
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if *old_p == p {
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warn!(
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"Node {:?} received Echo({:?}) multiple times from {:?}.",
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self.our_id(),
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HexProof(&p),
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sender_id,
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);
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return Ok(Step::default());
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} else {
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return Ok(Fault::new(sender_id.clone(), FaultKind::MultipleEchos).into());
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}
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}
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// Case where we have received an earlier `EchoHash`
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// message from sender_id with different root_hash.
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if let Some(EchoContent::Hash(hash)) = self.echos.get(sender_id) {
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if hash != p.root_hash() {
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return Ok(Fault::new(sender_id.clone(), FaultKind::MultipleEchos).into());
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}
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}
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// If the proof is invalid, log the faulty-node behavior, and ignore.
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if !self.validate_proof(&p, sender_id) {
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return Ok(Fault::new(sender_id.clone(), FaultKind::InvalidProof).into());
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}
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let hash = *p.root_hash();
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// Save the proof for reconstructing the tree later.
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self.echos.insert(sender_id.clone(), EchoContent::Full(p));
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let mut step = Step::default();
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// Upon receiving `N - 2f` `Echo`s with this root hash, send `CanDecode`
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if !self.can_decode_sent.contains(&hash)
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&& self.count_echos_full(&hash) >= self.coding.data_shard_count()
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{
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step.extend(self.send_can_decode(&hash)?);
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}
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// Upon receiving `N - f` `Echo`s with this root hash, multicast `Ready`.
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if !self.ready_sent && self.count_echos(&hash) >= self.val_set.num_correct() {
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step.extend(self.send_ready(&hash)?);
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}
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// Computes output if we have required number of `Echo`s and `Ready`s
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// Else returns Step::default()
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if self.ready_sent {
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step.extend(self.compute_output(&hash)?);
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}
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Ok(step)
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}
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fn handle_echo_hash(&mut self, sender_id: &N, hash: &Digest) -> Result<Step<N>> {
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// If the sender has already sent `EchoHash`, ignore.
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if let Some(EchoContent::Hash(old_hash)) = self.echos.get(sender_id) {
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if old_hash == hash {
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warn!(
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"Node {:?} received EchoHash({:?}) multiple times from {:?}.",
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self.our_id(),
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hash,
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sender_id,
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);
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return Ok(Step::default());
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} else {
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return Ok(Fault::new(sender_id.clone(), FaultKind::MultipleEchoHashes).into());
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}
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}
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// If the sender has already sent an `Echo` for the same hash, ignore.
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if let Some(EchoContent::Full(p)) = self.echos.get(sender_id) {
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if p.root_hash() == hash {
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return Ok(Step::default());
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} else {
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return Ok(Fault::new(sender_id.clone(), FaultKind::MultipleEchoHashes).into());
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}
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}
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// Save the hash for counting later.
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self.echos
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.insert(sender_id.clone(), EchoContent::Hash(*hash));
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if self.ready_sent || self.count_echos(&hash) < self.val_set.num_correct() {
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return self.compute_output(&hash);
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}
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// Upon receiving `N - f` `Echo`s with this root hash, multicast `Ready`.
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self.send_ready(&hash)
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}
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/// Handles a received `CanDecode` message.
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fn handle_can_decode(&mut self, sender_id: &N, hash: &Digest) -> Result<Step<N>> {
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// Save the hash for counting later. If hash from sender_id already exists, emit a warning.
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if let Some(nodes) = self.can_decodes.get(hash) {
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if nodes.contains(sender_id) {
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warn!(
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"Node {:?} received same CanDecode({:?}) multiple times from {:?}.",
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self.our_id(),
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hash,
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sender_id,
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);
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}
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}
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self.can_decodes
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.entry(*hash)
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.or_default()
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.insert(sender_id.clone());
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Ok(Step::default())
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}
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/// Handles a received `Ready` message.
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fn handle_ready(&mut self, sender_id: &N, hash: &Digest) -> Result<Step<N>> {
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// If the sender has already sent a `Ready` before, ignore.
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if let Some(old_hash) = self.readys.get(sender_id) {
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if old_hash == hash {
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warn!(
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"Node {:?} received Ready({:?}) multiple times from {:?}.",
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self.our_id(),
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hash,
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sender_id
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);
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return Ok(Step::default());
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} else {
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return Ok(Fault::new(sender_id.clone(), FaultKind::MultipleReadys).into());
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}
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}
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self.readys.insert(sender_id.clone(), hash.to_vec());
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let mut step = Step::default();
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// Upon receiving f + 1 matching Ready(h) messages, if Ready
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// has not yet been sent, multicast Ready(h).
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if self.count_readys(hash) == self.val_set.num_faulty() + 1 && !self.ready_sent {
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// Enqueue a broadcast of a Ready message.
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step.extend(self.send_ready(hash)?);
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}
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// Upon receiving 2f + 1 matching Ready(h) messages, send full
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// `Echo` message to every node who hasn't sent us a `CanDecode`
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if self.count_readys(hash) == 2 * self.val_set.num_faulty() + 1 {
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step.extend(self.send_echo_remaining(hash)?);
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}
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Ok(step.join(self.compute_output(hash)?))
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}
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/// Sends `Echo` message to all left nodes and handles it.
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fn send_echo_left(&mut self, p: Proof<Vec<u8>>) -> Result<Step<N>> {
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if !self.val_set.contains(&self.our_id) {
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return Ok(Step::default());
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}
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let echo_msg = Message::Echo(p.clone());
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let mut step = Step::default();
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let right = self.right_nodes().cloned().collect();
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// Send `Echo` message to all non-validating nodes and the ones on our left.
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let msg = Target::AllExcept(right).message(echo_msg);
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step.messages.push(msg);
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let our_id = &self.our_id().clone();
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Ok(step.join(self.handle_echo(our_id, p)?))
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}
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/// Sends `Echo` message to remaining nodes who haven't sent `CanDecode`
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fn send_echo_remaining(&mut self, hash: &Digest) -> Result<Step<N>> {
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self.echo_sent = true;
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if !self.val_set.contains(&self.our_id) {
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return Ok(Step::default());
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}
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let p = match self.echos.get(self.our_id()) {
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// Haven't received `Echo`.
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None | Some(EchoContent::Hash(_)) => return Ok(Step::default()),
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// Received `Echo` for different hash.
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Some(EchoContent::Full(p)) if p.root_hash() != hash => return Ok(Step::default()),
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Some(EchoContent::Full(p)) => p.clone(),
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};
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let echo_msg = Message::Echo(p);
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let mut step = Step::default();
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let senders = self.can_decodes.get(hash);
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let right = self
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.right_nodes()
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.filter(|id| senders.map_or(true, |s| !s.contains(id)))
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.cloned()
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.collect();
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step.messages.push(Target::Nodes(right).message(echo_msg));
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Ok(step)
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}
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/// Sends an `EchoHash` message and handles it. Does nothing if we are only an observer.
|
||
fn send_echo_hash(&mut self, hash: &Digest) -> Result<Step<N>> {
|
||
self.echo_hash_sent = true;
|
||
if !self.val_set.contains(&self.our_id) {
|
||
return Ok(Step::default());
|
||
}
|
||
let echo_hash_msg = Message::EchoHash(*hash);
|
||
let mut step = Step::default();
|
||
let right = self.right_nodes().cloned().collect();
|
||
let msg = Target::Nodes(right).message(echo_hash_msg);
|
||
step.messages.push(msg);
|
||
let our_id = &self.our_id().clone();
|
||
Ok(step.join(self.handle_echo_hash(our_id, hash)?))
|
||
}
|
||
|
||
/// Returns an iterator over all nodes to our right.
|
||
///
|
||
/// The nodes are arranged in a circle according to their ID, starting with our own. The first
|
||
/// _N - 2 f + g_ nodes are considered "to our left" and the rest "to our right".
|
||
///
|
||
/// These are the nodes to which we only send an `EchoHash` message in the beginning.
|
||
fn right_nodes(&self) -> impl Iterator<Item = &N> {
|
||
let our_id = self.our_id().clone();
|
||
let not_us = move |x: &&N| **x != our_id;
|
||
self.val_set
|
||
.all_ids()
|
||
.cycle()
|
||
.skip_while(not_us.clone())
|
||
.skip(self.val_set.num_correct() - self.val_set.num_faulty() + self.fault_estimate)
|
||
.take_while(not_us)
|
||
}
|
||
|
||
/// Sends a `CanDecode` message and handles it. Does nothing if we are only an observer.
|
||
fn send_can_decode(&mut self, hash: &Digest) -> Result<Step<N>> {
|
||
self.can_decode_sent.insert(hash.clone());
|
||
if !self.val_set.contains(&self.our_id) {
|
||
return Ok(Step::default());
|
||
}
|
||
|
||
let can_decode_msg = Message::CanDecode(*hash);
|
||
let mut step = Step::default();
|
||
|
||
let our_id = &self.our_id().clone();
|
||
let recipients = self
|
||
.val_set
|
||
.all_ids()
|
||
.filter(|id| match self.echos.get(id) {
|
||
Some(EchoContent::Hash(_)) | None => *id != our_id,
|
||
_ => false,
|
||
})
|
||
.cloned()
|
||
.collect();
|
||
let msg = Target::Nodes(recipients).message(can_decode_msg);
|
||
step.messages.push(msg);
|
||
Ok(step.join(self.handle_can_decode(our_id, hash)?))
|
||
}
|
||
|
||
/// Sends a `Ready` message and handles it. Does nothing if we are only an observer.
|
||
fn send_ready(&mut self, hash: &Digest) -> Result<Step<N>> {
|
||
self.ready_sent = true;
|
||
if !self.val_set.contains(&self.our_id) {
|
||
return Ok(Step::default());
|
||
}
|
||
let ready_msg = Message::Ready(*hash);
|
||
let step: Step<_> = Target::all().message(ready_msg).into();
|
||
let our_id = &self.our_id().clone();
|
||
Ok(step.join(self.handle_ready(our_id, hash)?))
|
||
}
|
||
|
||
/// Checks whether the conditions for output are met for this hash, and if so, sets the output
|
||
/// value.
|
||
fn compute_output(&mut self, hash: &Digest) -> Result<Step<N>> {
|
||
if self.decided
|
||
|| self.count_readys(hash) <= 2 * self.val_set.num_faulty()
|
||
|| self.count_echos_full(hash) < self.coding.data_shard_count()
|
||
{
|
||
return Ok(Step::default());
|
||
}
|
||
|
||
// Upon receiving 2f + 1 matching Ready(h) messages, wait for N − 2f Echo messages.
|
||
let mut leaf_values: Vec<Option<Box<[u8]>>> = self
|
||
.val_set
|
||
.all_ids()
|
||
.map(|id| {
|
||
self.echos
|
||
.get(id)
|
||
.and_then(EchoContent::proof)
|
||
.and_then(|p| {
|
||
if p.root_hash() == hash {
|
||
Some(p.value().clone().into_boxed_slice())
|
||
} else {
|
||
None
|
||
}
|
||
})
|
||
})
|
||
.collect();
|
||
if let Some(value) = self.decode_from_shards(&mut leaf_values, hash) {
|
||
self.decided = true;
|
||
Ok(Step::default().with_output(value))
|
||
} else {
|
||
let fault_kind = FaultKind::BroadcastDecoding;
|
||
Ok(Fault::new(self.proposer_id.clone(), fault_kind).into())
|
||
}
|
||
}
|
||
|
||
/// Interpolates the missing shards and glues together the data shards to retrieve the value.
|
||
/// This returns `None` if reconstruction failed or the reconstructed shards don't match the
|
||
/// root hash. This can only happen if the proposer provided invalid shards.
|
||
fn decode_from_shards(
|
||
&self,
|
||
leaf_values: &mut [Option<Box<[u8]>>],
|
||
root_hash: &Digest,
|
||
) -> Option<Vec<u8>> {
|
||
// Try to interpolate the Merkle tree using the Reed-Solomon erasure coding scheme.
|
||
self.coding.reconstruct_shards(leaf_values).ok()?;
|
||
|
||
// Collect shards for tree construction.
|
||
let shards: Vec<Vec<u8>> = leaf_values
|
||
.iter()
|
||
.filter_map(|l| l.as_ref().map(|v| v.to_vec()))
|
||
.collect();
|
||
|
||
debug!("{}: Reconstructed shards: {:0.10}", self, HexList(&shards));
|
||
|
||
// Construct the Merkle tree.
|
||
let mtree = MerkleTree::from_vec(shards);
|
||
// If the root hash of the reconstructed tree does not match the one
|
||
// received with proofs then abort.
|
||
if mtree.root_hash() != root_hash {
|
||
return None; // The proposer is faulty.
|
||
}
|
||
|
||
// Reconstruct the value from the data shards:
|
||
// Concatenate the leaf values that are data shards The first four bytes are
|
||
// interpreted as the payload size, and the padding beyond that size is dropped.
|
||
let count = self.coding.data_shard_count();
|
||
let mut bytes = mtree.into_values().into_iter().take(count).flatten();
|
||
let payload_len = match (bytes.next(), bytes.next(), bytes.next(), bytes.next()) {
|
||
(Some(b0), Some(b1), Some(b2), Some(b3)) => {
|
||
BigEndian::read_u32(&[b0, b1, b2, b3]) as usize
|
||
}
|
||
_ => return None, // The proposer is faulty: no payload size.
|
||
};
|
||
let payload: Vec<u8> = bytes.take(payload_len).collect();
|
||
debug!("{}: Glued data shards {:0.10}", self, HexFmt(&payload));
|
||
Some(payload)
|
||
}
|
||
|
||
/// Returns `true` if the proof is valid and has the same index as the node ID.
|
||
fn validate_proof(&self, p: &Proof<Vec<u8>>, id: &N) -> bool {
|
||
self.val_set.index(id) == Some(p.index()) && p.validate(self.val_set.num())
|
||
}
|
||
|
||
/// Returns the number of nodes that have sent us a full `Echo` message with this hash.
|
||
fn count_echos_full(&self, hash: &Digest) -> usize {
|
||
self.echos
|
||
.values()
|
||
.filter_map(EchoContent::proof)
|
||
.filter(|p| p.root_hash() == hash)
|
||
.count()
|
||
}
|
||
|
||
/// Returns the number of nodes that have sent us an `Echo` or `EchoHash` message with this hash.
|
||
fn count_echos(&self, hash: &Digest) -> usize {
|
||
self.echos.values().filter(|v| v.hash() == hash).count()
|
||
}
|
||
|
||
/// Returns the number of nodes that have sent us a `Ready` message with this hash.
|
||
fn count_readys(&self, hash: &Digest) -> usize {
|
||
self.readys
|
||
.values()
|
||
.filter(|h| h.as_slice() == hash)
|
||
.count()
|
||
}
|
||
}
|
||
|
||
impl<N: NodeIdT> fmt::Display for Broadcast<N> {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> result::Result<(), fmt::Error> {
|
||
write!(f, "{:?} Broadcast({:?})", self.our_id(), self.proposer_id)
|
||
}
|
||
}
|
||
|
||
/// A wrapper for `ReedSolomon` that doesn't panic if there are no parity shards.
|
||
#[derive(Debug)]
|
||
enum Coding {
|
||
/// A `ReedSolomon` instance with at least one parity shard.
|
||
ReedSolomon(Box<ReedSolomon<Field8>>),
|
||
/// A no-op replacement that doesn't encode or decode anything.
|
||
Trivial(usize),
|
||
}
|
||
|
||
impl Coding {
|
||
/// Creates a new `Coding` instance with the given number of shards.
|
||
fn new(data_shard_num: usize, parity_shard_num: usize) -> RseResult<Self> {
|
||
Ok(if parity_shard_num > 0 {
|
||
let rs = ReedSolomon::new(data_shard_num, parity_shard_num)?;
|
||
Coding::ReedSolomon(Box::new(rs))
|
||
} else {
|
||
Coding::Trivial(data_shard_num)
|
||
})
|
||
}
|
||
|
||
/// Returns the number of data shards.
|
||
fn data_shard_count(&self) -> usize {
|
||
match *self {
|
||
Coding::ReedSolomon(ref rs) => rs.data_shard_count(),
|
||
Coding::Trivial(dsc) => dsc,
|
||
}
|
||
}
|
||
|
||
/// Returns the number of parity shards.
|
||
fn parity_shard_count(&self) -> usize {
|
||
match *self {
|
||
Coding::ReedSolomon(ref rs) => rs.parity_shard_count(),
|
||
Coding::Trivial(_) => 0,
|
||
}
|
||
}
|
||
|
||
/// Constructs (and overwrites) the parity shards.
|
||
fn encode(&self, slices: &mut [&mut [u8]]) -> RseResult<()> {
|
||
match *self {
|
||
Coding::ReedSolomon(ref rs) => rs.encode(slices),
|
||
Coding::Trivial(_) => Ok(()),
|
||
}
|
||
}
|
||
|
||
/// If enough shards are present, reconstructs the missing ones.
|
||
fn reconstruct_shards(&self, shards: &mut [Option<Box<[u8]>>]) -> RseResult<()> {
|
||
match *self {
|
||
Coding::ReedSolomon(ref rs) => rs.reconstruct(shards),
|
||
Coding::Trivial(_) => {
|
||
if shards.iter().all(Option::is_some) {
|
||
Ok(())
|
||
} else {
|
||
Err(rse::Error::TooFewShardsPresent)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Content for `EchoHash` and `Echo` messages.
|
||
#[derive(Debug)]
|
||
enum EchoContent {
|
||
/// `EchoHash` message.
|
||
Hash(Digest),
|
||
/// `Echo` message
|
||
Full(Proof<Vec<u8>>),
|
||
}
|
||
|
||
impl EchoContent {
|
||
/// Returns hash of the message from either message types.
|
||
pub fn hash(&self) -> &Digest {
|
||
match &self {
|
||
EchoContent::Hash(h) => h,
|
||
EchoContent::Full(p) => p.root_hash(),
|
||
}
|
||
}
|
||
|
||
/// Returns Proof if type is Full else returns None.
|
||
pub fn proof(&self) -> Option<&Proof<Vec<u8>>> {
|
||
match &self {
|
||
EchoContent::Hash(_) => None,
|
||
EchoContent::Full(p) => Some(p),
|
||
}
|
||
}
|
||
}
|