From 6a450a8b3fc4320745e7c1b474987f18e4dbca5e Mon Sep 17 00:00:00 2001
From: Hugo Domingos <h.domingos@ua.pt>
Date: Wed, 11 Mar 2026 20:16:48 +0000
Subject: [PATCH] Fix max hop limit for GBC packets

---
 src/flexstack/btp/router.py                  | 3 ++-
 src/flexstack/geonet/common_header.py        | 3 +--
 src/flexstack/geonet/router.py               | 2 +-
 src/flexstack/geonet/service_access_point.py | 3 +++
 4 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/flexstack/btp/router.py b/src/flexstack/btp/router.py
index 40fb814..8003486 100644
--- a/src/flexstack/btp/router.py
+++ b/src/flexstack/btp/router.py
@@ -81,7 +81,8 @@ def btp_data_request(self, request: BTPDataRequest) -> None:
                 communication_profile=request.communication_profile,
                 traffic_class=request.traffic_class,
                 data=data,
-                length=len(data)
+                length=len(data),
+                max_hop_limit=request.max_hop_limit,
             )
             self.logging.debug(
                 "Sending BTP Data Request: %s", gn_data_request.data)
diff --git a/src/flexstack/geonet/common_header.py b/src/flexstack/geonet/common_header.py
index d127040..6deb777 100644
--- a/src/flexstack/geonet/common_header.py
+++ b/src/flexstack/geonet/common_header.py
@@ -70,8 +70,7 @@ def initialize_with_request(cls, request: GNDataRequest) -> "CommonHeader":
         if ht == HeaderType.TSB and hst == TopoBroadcastHST.SINGLE_HOP:
             mhl = 1
         else:
-            # TODO: Set the maximum hop limit on other cases than SHB As specified in: Section 10.3.4 Table 20
-            mhl = 1
+            mhl = request.max_hop_limit
         return cls(nh=nh, reserved=0, ht=ht, hst=hst, tc=tc, flags=0, pl=pl, mhl=mhl)  # type: ignore
 
     def encode_to_int(self) -> int:
diff --git a/src/flexstack/geonet/router.py b/src/flexstack/geonet/router.py
index a5bafad..5e26d3a 100644
--- a/src/flexstack/geonet/router.py
+++ b/src/flexstack/geonet/router.py
@@ -678,7 +678,7 @@ def gn_data_indicate(self, packet: bytes) -> None:
             # Decap the common header
             common_header = CommonHeader.decode_from_bytes(packet[0:8])
             packet = packet[8:]
-            if basic_header.rhl > self.mib.itsGnDefaultHopLimit:
+            if basic_header.rhl > common_header.mhl:
                 raise DecapError("Hop limit exceeded")
             # TODO: Forwarding packet buffer flush
             if common_header.ht == HeaderType.ANY:
diff --git a/src/flexstack/geonet/service_access_point.py b/src/flexstack/geonet/service_access_point.py
index 333eace..c19e1ba 100644
--- a/src/flexstack/geonet/service_access_point.py
+++ b/src/flexstack/geonet/service_access_point.py
@@ -406,6 +406,8 @@ class GNDataRequest:
         Payload.
     area : Area
         Area of the GBC algorithm. Only used when the packet transport type is GBC.
+    max_hop_limit : int
+        Maximum hop limit for the packet. Default is 10.
 
     THIS CLASS WILL BE EXTENDED WHEN FURTHER PACKET TYPES ARE IMPLEMENTED
     """
@@ -421,6 +423,7 @@ class GNDataRequest:
     length: int = 0
     data: bytes = b""
     area: Area = field(default_factory=Area)
+    max_hop_limit: int = 10
 
     def to_dict(self) -> dict:
         """