fix(firewall): remove decoding bundle for expired message

sync/firewall/firewall.go

@@ -217,35 +217,13 @@ func (f *Firewall) isExpiredMessage(msgData []byte) bool {
 		return true
 	}
 
-	// TODO: we remove on the version v1.8.0
-	consensusHeightExtracted := false
-	var consensusHeight uint32
-	consensusHeightBytes := msgData[msgLen-6:]
-	// Check if consensus height is set. Refer to the bundle encoding for more details.
-	if consensusHeightBytes[0] == 0x04 && consensusHeightBytes[1] == 0x1a {
-		consensusHeight = binary.BigEndian.Uint32(consensusHeightBytes[2:])
-
-		if consensusHeight > 2_900_000 {
-			consensusHeightExtracted = true
-		}
-	}
-	if !consensusHeightExtracted {
-		// Decoding the message at this level is costly, and we should avoid it.
-		// In future versions, this code can be removed.
-		// However, at the time of writing this code, we need it to prevent replay attacks.
-		bdl := new(bundle.Bundle)
-		_, err := bdl.Decode(bytes.NewReader(msgData))
-		if err != nil {
-			return true
-		}
-
-		consensusHeight = bdl.Message.ConsensusHeight()
-	}
+	consensusHeightRaw := msgData[msgLen-6:]
+	consensusHeight := binary.BigEndian.Uint32(consensusHeightRaw[2:])
 
 	// The message is expired, or the consensus height is behind the network's current height.
-	// In either case, the message is dropped and won't be propagated.
 	if f.state.LastBlockHeight() > 0 && consensusHeight < f.state.LastBlockHeight()-1 {
-		f.logger.Warn("firewall: expired message", "message height", consensusHeight, "our height", f.state.LastBlockHeight())
+		f.logger.Warn("firewall: expired message", "message height", consensusHeight,
+			"our height", f.state.LastBlockHeight())
 
 		return true
 	}