Add Batch messages from processor, verify Batchs published on-chain

Renames Update to SignedBatch.

Checks Batch equality via a hash of the InInstructions. That prevents needing
to keep the Batch in node state or TX introspect.

coordinator/src/substrate/db.rs

@@ -2,7 +2,10 @@ use scale::{Encode, Decode};
 
 pub use serai_db::*;
 
-use serai_client::validator_sets::primitives::{Session, KeyPair};
+use serai_client::{
+  primitives::NetworkId,
+  validator_sets::primitives::{Session, KeyPair},
+};
 
 #[derive(Debug)]
 pub struct SubstrateDb<D: Db>(pub D);
@@ -55,4 +58,23 @@ impl<D: Db> SubstrateDb<D> {
     txn.put(key_0, session.clone());
     txn.put(Self::session_key(&key_pair.1), session);
   }
+
+  fn batch_instructions_key(network: NetworkId, id: u32) -> Vec<u8> {
+    Self::substrate_key(b"batch", (network, id).encode())
+  }
+  pub fn batch_instructions_hash<G: Get>(
+    getter: &G,
+    network: NetworkId,
+    id: u32,
+  ) -> Option<[u8; 32]> {
+    getter.get(Self::batch_instructions_key(network, id)).map(|bytes| bytes.try_into().unwrap())
+  }
+  pub fn save_batch_instructions_hash(
+    txn: &mut D::Transaction<'_>,
+    network: NetworkId,
+    id: u32,
+    hash: [u8; 32],
+  ) {
+    txn.put(Self::batch_instructions_key(network, id), hash);
+  }
 }

coordinator/src/substrate/mod.rs

@@ -123,7 +123,8 @@ async fn handle_key_gen<D: Db, Pro: Processors>(
   Ok(())
 }
 
-async fn handle_batch_and_burns<Pro: Processors>(
+async fn handle_batch_and_burns<D: Db, Pro: Processors>(
+  db: &mut D,
   processors: &Pro,
   serai: &Serai,
   block: &Block,
@@ -149,9 +150,15 @@ async fn handle_batch_and_burns<Pro: Processors>(
   let mut burns = HashMap::new();
 
   for batch in serai.get_batch_events(hash).await? {
-    if let InInstructionsEvent::Batch { network, id, block: network_block } = batch {
+    if let InInstructionsEvent::Batch { network, id, block: network_block, instructions_hash } =
+      batch
+    {
       network_had_event(&mut burns, &mut batches, network);
 
+      let mut txn = db.txn();
+      SubstrateDb::<D>::save_batch_instructions_hash(&mut txn, network, id, instructions_hash);
+      txn.commit();
+
       // Make sure this is the only Batch event for this network in this Block
       assert!(batch_block.insert(network, network_block).is_none());
 
@@ -277,7 +284,7 @@ async fn handle_block<D: Db, CNT: Clone + Fn(&mut D, TributarySpec), Pro: Proces
   // This does break the uniqueness of (hash, event_id) -> one event, yet
   // (network, (hash, event_id)) remains valid as a unique ID for an event
   if !SubstrateDb::<D>::handled_event(&db.0, hash, event_id) {
-    handle_batch_and_burns(processors, serai, &block).await?;
+    handle_batch_and_burns(&mut db.0, processors, serai, &block).await?;
   }
   let mut txn = db.0.txn();
   SubstrateDb::<D>::handle_event(&mut txn, hash, event_id);