fix path af_packet interface

backend/src/utilities/packet_tracker.py

@@ -470,13 +470,15 @@ class PacketTracker:
         ingress_iface = ingress_observation.get("iface")
         ingress_timestamp = ingress_observation.get("timestamp")
 
-        if ingress_iface and payload.get("ingress_if") in {None, ""}:
+        if ingress_iface and payload.get("ingress_if") != ingress_iface:
             payload["ingress_if"] = ingress_iface
             changed = True
-        if ingress_timestamp and payload.get("ingress_seen_at") is None:
+        if ingress_timestamp:
             try:
-                payload["ingress_seen_at"] = datetime.fromisoformat(str(ingress_timestamp))
-                changed = True
+                parsed_ingress_seen_at = datetime.fromisoformat(str(ingress_timestamp))
+                if payload.get("ingress_seen_at") != parsed_ingress_seen_at:
+                    payload["ingress_seen_at"] = parsed_ingress_seen_at
+                    changed = True
             except Exception:
                 pass
 
@@ -485,13 +487,15 @@ class PacketTracker:
 
         egress_iface = egress_observation.get("iface")
         egress_timestamp = egress_observation.get("timestamp")
-        if egress_iface and payload.get("egress_if") in {None, ""}:
+        if egress_iface and payload.get("egress_if") != egress_iface:
             payload["egress_if"] = egress_iface
             changed = True
-        if egress_timestamp and payload.get("egress_seen_at") is None:
+        if egress_timestamp:
             try:
-                payload["egress_seen_at"] = datetime.fromisoformat(str(egress_timestamp))
-                changed = True
+                parsed_egress_seen_at = datetime.fromisoformat(str(egress_timestamp))
+                if payload.get("egress_seen_at") != parsed_egress_seen_at:
+                    payload["egress_seen_at"] = parsed_egress_seen_at
+                    changed = True
             except Exception:
                 pass