Basic Gossip Validator

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;