Basic Gossip Validator

Cargo.lock

@@ -6878,6 +6878,24 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "sc-network-gossip"
+version = "0.10.0-dev"
+source = "git+https://github.com/serai-dex/substrate#176b4e8cfc110f339d88ebd414602bc3833da3c3"
+dependencies = [
+ "ahash",
+ "futures",
+ "futures-timer",
+ "libp2p",
+ "log",
+ "lru 0.7.8",
+ "sc-network-common",
+ "sc-peerset",
+ "sp-runtime",
+ "substrate-prometheus-endpoint",
+ "tracing",
+]
+
 [[package]]
 name = "sc-network-light"
 version = "0.10.0-dev"
@@ -7521,6 +7539,7 @@ dependencies = [
  "sc-consensus",
  "sc-executor",
  "sc-network",
+ "sc-network-gossip",
  "sc-service",
  "sc-transaction-pool",
  "serai-runtime",

substrate/tendermint/client/Cargo.toml

@@ -36,6 +36,7 @@ sc-transaction-pool = { git = "https://github.com/serai-dex/substrate" }
 sc-basic-authorship = { git = "https://github.com/serai-dex/substrate" }
 sc-executor = { git = "https://github.com/serai-dex/substrate" }
 sc-network = { git = "https://github.com/serai-dex/substrate" }
+sc-network-gossip = { git = "https://github.com/serai-dex/substrate" }
 sc-service = { git = "https://github.com/serai-dex/substrate" }
 sc-client-api = { git = "https://github.com/serai-dex/substrate" }
 sc-consensus = { git = "https://github.com/serai-dex/substrate" }

substrate/tendermint/client/src/gossip.rs

@@ -0,0 +1,43 @@
+use std::sync::{Arc, RwLock};
+
+use sp_core::{Decode, sr25519::Signature};
+use sp_runtime::traits::{Hash, Header, Block};
+
+use sc_network::PeerId;
+use sc_network_gossip::{Validator, ValidatorContext, ValidationResult};
+
+use tendermint_machine::{SignedMessage, ext::SignatureScheme};
+
+#[derive(Clone)]
+struct TendermintGossip<S: SignatureScheme<ValidatorId = u16, Signature = Signature>> {
+  number: Arc<RwLock<u64>>,
+  signature_scheme: Arc<S>,
+}
+
+impl<B: Block, S: SignatureScheme<ValidatorId = u16, Signature = Signature>> Validator<B>
+  for TendermintGossip<S>
+{
+  fn validate(
+    &self,
+    _: &mut dyn ValidatorContext<B>,
+    _: &PeerId,
+    data: &[u8],
+  ) -> ValidationResult<B::Hash> {
+    let msg = match SignedMessage::<u16, B, Signature>::decode(&mut &*data) {
+      Ok(msg) => msg,
+      Err(_) => return ValidationResult::Discard,
+    };
+
+    if msg.number().0 < *self.number.read().unwrap() {
+      return ValidationResult::Discard;
+    }
+
+    if !msg.verify_signature(&self.signature_scheme) {
+      return ValidationResult::Discard;
+    }
+
+    ValidationResult::ProcessAndKeep(<<B::Header as Header>::Hashing as Hash>::hash(
+      &[b"Tendermint Topic".as_ref(), &msg.number().0.to_le_bytes()].concat(),
+    ))
+  }
+}

substrate/tendermint/client/src/lib.rs

@@ -20,6 +20,8 @@ mod verifier;
 mod import_queue;
 use import_queue::TendermintImportQueue;
 
+mod gossip;
+
 mod select_chain;
 pub use select_chain::TendermintSelectChain;
 

substrate/tendermint/machine/src/lib.rs

@@ -81,6 +81,21 @@ pub struct SignedMessage<V: ValidatorId, B: Block, S: Signature> {
   sig: S,
 }
 
+impl<V: ValidatorId, B: Block, S: Signature> SignedMessage<V, B, S> {
+  /// Number of the block this message is attempting to add to the chain.
+  pub fn number(&self) -> BlockNumber {
+    self.msg.number
+  }
+
+  #[must_use]
+  pub fn verify_signature<Scheme: SignatureScheme<ValidatorId = V, Signature = S>>(
+    &self,
+    signer: &Arc<Scheme>,
+  ) -> bool {
+    signer.verify(self.msg.sender, &self.msg.encode(), &self.sig)
+  }
+}
+
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 enum TendermintError<V: ValidatorId> {
   Malicious(V),
@@ -302,7 +317,7 @@ impl<N: Network + 'static> TendermintMachine<N> {
           loop {
             match msg_recv.try_recv() {
               Ok(msg) => {
-                if !machine.signer.verify(msg.msg.sender, &msg.msg.encode(), &msg.sig) {
+                if !msg.verify_signature(&machine.signer) {
                   continue;
                 }
                 machine.queue.push((false, msg.msg));