From 6e93e4dba314da1c5d60564df2d4058e870fc071 Mon Sep 17 00:00:00 2001
From: Markus Schmidl <markus.schmidl@mailbox.tu-dresden.de>
Date: Sat, 7 Sep 2024 01:54:33 +0200
Subject: [PATCH] handle address of null pdu in the uplink

---
 include/l2/upper_mac_packet_builder.hpp | 34 ++++++++++++++++++++-----
 src/l2/upper_mac.cpp                    |  3 +++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/include/l2/upper_mac_packet_builder.hpp b/include/l2/upper_mac_packet_builder.hpp
index e33604f..3b4bcf8 100644
--- a/include/l2/upper_mac_packet_builder.hpp
+++ b/include/l2/upper_mac_packet_builder.hpp
@@ -53,6 +53,28 @@ struct UpperMacPackets {
         }
     }
 
+    /// Distribute the information of the uplink c-plane signalling null pdu to all other c-plane signalling packets.
+    /// This operation will associate uplink packets with no address (MacFragmentUplink and MacEndUplink) with the
+    /// address of the uplink null pdu.
+    auto apply_uplink_null_pdu_information() -> void {
+        std::optional<UpperMacCPlaneSignallingPacket> null_pdu;
+
+        for (auto const& packet : c_plane_signalling_packets_) {
+            if (packet.is_null_pdu()) {
+                null_pdu = packet;
+            }
+        }
+
+        if (null_pdu) {
+            for (auto& packet : c_plane_signalling_packets_) {
+                if ((packet.type_ == MacPacketType::kMacFragmentUplink) ||
+                    (packet.type_ == MacPacketType::kMacEndUplink)) {
+                    packet.address_ = null_pdu->address_;
+                }
+            }
+        }
+    }
+
     /// Check if the packet contains data that is of importance for C-Plane or U-Plane
     /// \return true if the UpperMacPackets contain user or control plane data (either signalling or traffic)
     [[nodiscard]] auto has_user_or_control_plane_data() const -> bool {
@@ -108,22 +130,22 @@ class UpperMacPacketBuilder {
     /// \param channel the logical channel on which the packets are sent
     /// \param data the BitVector which holds the packets
     /// \return the parsed c-plane signalling packets
-    [[nodiscard]] static auto parse_c_plane_signalling(BurstType burst_type, LogicalChannel channel, BitVector&& data)
-        -> std::vector<UpperMacCPlaneSignallingPacket>;
+    [[nodiscard]] static auto parse_c_plane_signalling(BurstType burst_type, LogicalChannel channel,
+                                                       BitVector&& data) -> std::vector<UpperMacCPlaneSignallingPacket>;
 
     /// Parse the user plane signalling packet contained in a BitVector
     /// \param channel the logical channel on which the packet is sent
     /// \param data the BitVector which holds the packet
     /// \return the parsed u-plane signalling packet
-    [[nodiscard]] static auto parse_u_plane_signalling(LogicalChannel channel, BitVector&& data)
-        -> UpperMacUPlaneSignallingPacket;
+    [[nodiscard]] static auto parse_u_plane_signalling(LogicalChannel channel,
+                                                       BitVector&& data) -> UpperMacUPlaneSignallingPacket;
 
     /// Parse the user plane traffic packet contained in a BitVector
     /// \param channel the logical channel on which the packet is sent
     /// \param data the BitVector which holds the packet
     /// \return the parsed u-plane traffic packet
-    [[nodiscard]] static auto parse_u_plane_traffic(LogicalChannel channel, BitVector&& data)
-        -> UpperMacUPlaneTrafficPacket;
+    [[nodiscard]] static auto parse_u_plane_traffic(LogicalChannel channel,
+                                                    BitVector&& data) -> UpperMacUPlaneTrafficPacket;
 
   public:
     UpperMacPacketBuilder() = default;
diff --git a/src/l2/upper_mac.cpp b/src/l2/upper_mac.cpp
index 0c590cf..06c4d25 100644
--- a/src/l2/upper_mac.cpp
+++ b/src/l2/upper_mac.cpp
@@ -90,6 +90,9 @@ auto UpperMac::process(const Slots& slots) -> void {
         }
     }
 
+    /// This step takes care of adding the correct adresses for some uplink packets.
+    packets.apply_uplink_null_pdu_information();
+
     try {
         processPackets(std::move(packets));
     } catch (std::runtime_error& e) {