From f9b457d329dc3a727dab3be534d12d5f1dc824f4 Mon Sep 17 00:00:00 2001
From: DeFiDude <59237470+DeFiDude@users.noreply.github.com>
Date: Sun, 26 Jul 2026 02:11:21 -0600
Subject: [PATCH] transport: reject foreign IFAC ingress

---
 crates/rns-transport/src/actor/inbound.rs |  8 +++++++-
 crates/rns-transport/src/actor/mod.rs     | 23 +++++++++++++++++++++++
 crates/rns-transport/src/constants.rs     |  6 ++++--
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/crates/rns-transport/src/actor/inbound.rs b/crates/rns-transport/src/actor/inbound.rs
index d9f24c1..651d49e 100644
--- a/crates/rns-transport/src/actor/inbound.rs
+++ b/crates/rns-transport/src/actor/inbound.rs
@@ -28,6 +28,12 @@ impl TransportActor {
                         return;
                     }
                 }
+            } else if crate::ifac::has_ifac_flag(&packet.raw) {
+                trace!(
+                    interface_id = packet.interface_id,
+                    "IFAC packet received on clear interface, dropping packet"
+                );
+                return;
             } else {
                 packet.raw.clone()
             }
@@ -736,7 +742,7 @@ impl TransportActor {
             return;
         }
 
-        tracing::info!(
+        tracing::debug!(
             dest = %hex::encode(header.destination_hash),
             is_local = self.local_destinations.contains(&header.destination_hash),
             has_channel = self.destination_channels.contains_key(&header.destination_hash),
diff --git a/crates/rns-transport/src/actor/mod.rs b/crates/rns-transport/src/actor/mod.rs
index d0496f2..080fa36 100644
--- a/crates/rns-transport/src/actor/mod.rs
+++ b/crates/rns-transport/src/actor/mod.rs
@@ -3879,6 +3879,29 @@ mod tests {
         assert!(!actor.path_table.has_path(&dest_hash));
     }
 
+    #[test]
+    fn test_clear_interface_rejects_ifac_flag_before_packet_accounting() {
+        let (mut actor, _tx) = TransportActor::new();
+        let (entry, _rx) = make_test_interface("clear_in");
+        actor.interfaces.insert(1, entry);
+
+        let (raw, _dest_hash) = make_valid_announce("test.ifac_on_clear", 0);
+        let mut raw = raw.to_vec();
+        raw[0] |= 0x80;
+
+        actor.on_inbound(InboundPacket {
+            raw: Bytes::from(raw),
+            interface_id: 1,
+            rssi: None,
+            snr: None,
+            q: None,
+        });
+
+        assert!(actor.packet_hashlist.is_empty());
+        assert!(actor.packet_metrics.is_empty());
+        assert!(actor.path_table.is_empty());
+    }
+
     #[test]
     fn test_announce_retransmit() {
         let (mut actor, _tx) = TransportActor::new();
diff --git a/crates/rns-transport/src/constants.rs b/crates/rns-transport/src/constants.rs
index c6f8399..879a965 100644
--- a/crates/rns-transport/src/constants.rs
+++ b/crates/rns-transport/src/constants.rs
@@ -68,8 +68,10 @@ pub const PATH_REQUEST_RG: f64 = 1.5;
 /// Minimum interval between path requests (seconds).
 pub const PATH_REQUEST_MI: f64 = 20.0;
 
-/// Maximum packet hashes before rotation. Set to 2M with rotation at
-/// `maxsize/2` so effective history matches Python's 1M-no-rotation window.
+/// Maximum packet hashes retained across both generations.
+///
+/// Python retains roughly one million hashes. Rust deliberately retains up
+/// to two million for a longer bounded replay window; see RNS-D0056.
 pub const HASHLIST_MAXSIZE: usize = 2_000_000;
 
 /// Job loop period (250ms).