add replay detection to packet processing

common/mixnode-common/src/packet_processor/processor.rs

@@ -3,6 +3,7 @@
 
 use crate::measure;
 use crate::packet_processor::error::MixProcessingError;
+use crate::packet_processor::replay_detection::ReplayDetector;
 use log::*;
 use nym_sphinx_acknowledgements::surb_ack::SurbAck;
 use nym_sphinx_addressing::nodes::NymNodeRoutingAddress;
@@ -40,6 +41,9 @@ pub enum MixProcessingResult {
 pub struct SphinxPacketProcessor {
     /// Private sphinx key of this node required to unwrap received sphinx packet.
     sphinx_key: Arc<PrivateKey>,
+
+    /// Detector of replay attack
+    replay_detector: ReplayDetector,
 }
 
 impl SphinxPacketProcessor {
@@ -47,6 +51,7 @@ impl SphinxPacketProcessor {
     pub fn new(sphinx_key: PrivateKey) -> Self {
         SphinxPacketProcessor {
             sphinx_key: Arc::new(sphinx_key),
+            replay_detector: ReplayDetector::new(),
         }
     }
 
@@ -184,7 +189,7 @@ impl SphinxPacketProcessor {
         match packet {
             NymProcessedPacket::Sphinx(packet) => {
                 match packet {
-                    ProcessedPacket::ForwardHop(packet, address, delay) => self
+                    ProcessedPacket::ForwardHop(packet, address, delay, _) => self
                         .process_forward_hop(
                             NymPacket::Sphinx(*packet),
                             address,
@@ -193,12 +198,13 @@ impl SphinxPacketProcessor {
                         ),
                     // right now there's no use for the surb_id included in the header - probably it should get removed from the
                     // sphinx all together?
-                    ProcessedPacket::FinalHop(destination, _, payload) => self.process_final_hop(
-                        destination,
-                        payload.recover_plaintext()?,
-                        packet_size,
-                        packet_type,
-                    ),
+                    ProcessedPacket::FinalHop(destination, _, payload, _) => self
+                        .process_final_hop(
+                            destination,
+                            payload.recover_plaintext()?,
+                            packet_size,
+                            packet_type,
+                        ),
                 }
             }
             NymProcessedPacket::Outfox(packet) => {
@@ -239,6 +245,10 @@ impl SphinxPacketProcessor {
             // unwrap the sphinx packet and if possible and appropriate, cache keys
             let processed_packet = self.perform_initial_unwrapping(received)?;
 
+            //check for replay attack
+            self.replay_detector
+                .handle_replay_tag(&processed_packet.replay_tag())?;
+
             // for forward packets, extract next hop and set delay (but do NOT delay here)
             // for final packets, extract SURBAck
             let final_processing_result =