Improve encapsulation of logic relating to Layer attachment to Packet.

Packet++/header/Layer.h

@@ -30,6 +30,59 @@ namespace pcpp
 
 	class Packet;
 
+	namespace internal
+	{
+		/// @brief Holds information about a Layer's data and object ownership.
+		struct LayerAllocationInfo
+		{
+			/// @brief Pointer to the Packet this layer is attached to (if any).
+			///
+			/// If the layer is attached to a Packet, the layer's memory span (data) is considered managed by the
+			/// Packet. The Packet is responsible for keeping the layer's memory span valid and updating it should it
+			/// become necessary as long as the layer is attached to it.
+			///
+			/// In an event the Packet is destroyed, all of its attached layers's memory views are considered invalid.
+			/// Accessing layer data after the Packet is destroyed results in undefined behavior.
+			///
+			/// If nullptr, the layer is not attached to any Packet and is considered unmanaged.
+			/// It also means the layer's memory span is considered owned by the layer itself and will be freed when
+			/// the layer is destroyed.
+			Packet* attachedPacket = nullptr;
+
+			/// @brief Controls if the layer object is considered managed by the attached Packet
+			///
+			/// If 'true', the Layer object is considered managed by the attached Packet and will be tracked and freed
+			/// by it
+			///
+			/// If 'false', the Layer object is considered unmanaged and the user is responsible for freeing it.
+			/// This is commonly the case for layers created on the stack and attached to a Packet.
+			bool managedByPacket = false;
+
+			/// @brief Sets the state of attachment to a specified Packet
+			/// @param packet Pointer to the Packet this layer is attached to (or nullptr if not attached to any Packet)
+			/// @param managed True if the layer object's lifetime is to be managed by the Packet, false otherwise
+			/// @param force If true, bypasses the check for existing attachment. Default is false.
+			/// @throws std::runtime_error if the layer is already attached to a Packet and 'force' is false
+			void attachPacket(Packet* packet, bool managed, bool force = false)
+			{
+				if (!force && attachedPacket != nullptr)
+				{
+					throw std::runtime_error("Layer is already attached to a Packet");
+				}
+
+				attachedPacket = packet;
+				managedByPacket = managed;
+			}
+
+			/// @brief Clears the attachment to any Packet, resetting to unmanaged state.
+			void detach()
+			{
+				attachedPacket = nullptr;
+				managedByPacket = false;
+			}
+		};
+	}  // namespace internal
+
 	/// @class Layer
 	/// Layer is the base class for all protocol layers. Each protocol supported in PcapPlusPlus has a class that
 	/// inherits Layer.
@@ -125,7 +178,7 @@ namespace pcpp
 		/// by the layer itself
 		bool isAllocatedToPacket() const
 		{
-			return m_Packet != nullptr;
+			return m_AllocationInfo.attachedPacket != nullptr;
 		}
 
 		/// Copy the raw data of this layer to another array
@@ -160,26 +213,40 @@ namespace pcpp
 	protected:
 		uint8_t* m_Data;
 		size_t m_DataLen;
-		Packet* m_Packet;
 		ProtocolType m_Protocol;
 		Layer* m_NextLayer;
 		Layer* m_PrevLayer;
-		bool m_IsAllocatedInPacket;
 
-		Layer()
-		    : m_Data(nullptr), m_DataLen(0), m_Packet(nullptr), m_Protocol(UnknownProtocol), m_NextLayer(nullptr),
-		      m_PrevLayer(nullptr), m_IsAllocatedInPacket(false)
+	private:
+		internal::LayerAllocationInfo m_AllocationInfo;
+
+	protected:
+		Layer() : m_Data(nullptr), m_DataLen(0), m_Protocol(UnknownProtocol), m_NextLayer(nullptr), m_PrevLayer(nullptr)
 		{}
 
 		Layer(uint8_t* data, size_t dataLen, Layer* prevLayer, Packet* packet, ProtocolType protocol = UnknownProtocol)
-		    : m_Data(data), m_DataLen(dataLen), m_Packet(packet), m_Protocol(protocol), m_NextLayer(nullptr),
-		      m_PrevLayer(prevLayer), m_IsAllocatedInPacket(false)
+		    : m_Data(data), m_DataLen(dataLen), m_Protocol(protocol), m_NextLayer(nullptr), m_PrevLayer(prevLayer),
+		      m_AllocationInfo{ packet, false }
 		{}
 
 		// Copy c'tor
 		Layer(const Layer& other);
 		Layer& operator=(const Layer& other);
 
+		/// @brief Get a pointer to the Packet this layer is attached to (if any).
+		/// @return A pointer to the Packet this layer is attached to, or nullptr if the layer is not attached.
+		Packet* getAttachedPacket()
+		{
+			return m_AllocationInfo.attachedPacket;
+		}
+
+		/// @brief Get a pointer to the Packet this layer is attached to (if any).
+		/// @return A const pointer to the Packet this layer is attached to, or nullptr if the layer is not attached.
+		Packet const* getAttachedPacket() const
+		{
+			return m_AllocationInfo.attachedPacket;
+		}
+
 		void setNextLayer(Layer* nextLayer)
 		{
 			m_NextLayer = nextLayer;

Packet++/src/BgpLayer.cpp

@@ -87,7 +87,7 @@ namespace pcpp
 		uint8_t* payload = m_Data + headerLen;
 		size_t payloadLen = m_DataLen - headerLen;
 
-		m_NextLayer = BgpLayer::parseBgpLayer(payload, payloadLen, this, m_Packet);
+		m_NextLayer = BgpLayer::parseBgpLayer(payload, payloadLen, this, getAttachedPacket());
 	}
 
 	std::string BgpLayer::toString() const
@@ -120,10 +120,10 @@ namespace pcpp
 
 	bool BgpLayer::extendLayer(int offsetInLayer, size_t numOfBytesToExtend)
 	{
-		if (m_Packet != nullptr)
+		if (getAttachedPacket() != nullptr)
 		{
-			int rawPacketLen = m_Packet->getRawPacket()->getRawDataLen();
-			const uint8_t* rawPacketPtr = m_Packet->getRawPacket()->getRawData();
+			int rawPacketLen = getAttachedPacket()->getRawPacket()->getRawDataLen();
+			const uint8_t* rawPacketPtr = getAttachedPacket()->getRawPacket()->getRawData();
 
 			if (m_Data - rawPacketPtr + static_cast<ptrdiff_t>(offsetInLayer) > static_cast<ptrdiff_t>(rawPacketLen))
 			{
@@ -143,10 +143,10 @@ namespace pcpp
 
 	bool BgpLayer::shortenLayer(int offsetInLayer, size_t numOfBytesToShorten)
 	{
-		if (m_Packet != nullptr)
+		if (getAttachedPacket() != nullptr)
 		{
-			int rawPacketLen = m_Packet->getRawPacket()->getRawDataLen();
-			const uint8_t* rawPacketPtr = m_Packet->getRawPacket()->getRawData();
+			int rawPacketLen = getAttachedPacket()->getRawPacket()->getRawDataLen();
+			const uint8_t* rawPacketPtr = getAttachedPacket()->getRawPacket()->getRawData();
 
 			if (m_Data - rawPacketPtr + static_cast<ptrdiff_t>(offsetInLayer) +
 			        static_cast<ptrdiff_t>(numOfBytesToShorten) >

Packet++/src/CiscoHdlcLayer.cpp

@@ -55,20 +55,20 @@ namespace pcpp
 		case CISCO_HDLC_TYPE_IP:
 		{
 			m_NextLayer = IPv4Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		}
 		case CISCO_HDLC_TYPE_IPV6:
 		{
 			m_NextLayer = IPv6Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		}
 		default:
 		{
-			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 			break;
 		}
 		}

Packet++/src/CotpLayer.cpp

@@ -73,8 +73,8 @@ namespace pcpp
 		size_t payloadLen = m_DataLen - headerLen;
 
 		if (S7CommLayer::isDataValid(payload, payloadLen))
-			m_NextLayer = new S7CommLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new S7CommLayer(payload, payloadLen, this, getAttachedPacket());
 		else
-			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 	}
 }  // namespace pcpp

Packet++/src/DoIpLayer.cpp

@@ -396,7 +396,7 @@ namespace pcpp
 			uint8_t* payload = m_Data + headerLen;
 			size_t payloadLen = m_DataLen - headerLen;
 
-			constructNextLayer<PayloadLayer>(payload, payloadLen, m_Packet);
+			constructNextLayer<PayloadLayer>(payload, payloadLen, getAttachedPacket());
 		}
 	}
 

Packet++/src/EthDot3Layer.cpp

@@ -30,9 +30,9 @@ namespace pcpp
 		size_t payloadLen = m_DataLen - sizeof(ether_dot3_header);
 
 		if (LLCLayer::isDataValid(payload, payloadLen))
-			m_NextLayer = new LLCLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new LLCLayer(payload, payloadLen, this, getAttachedPacket());
 		else
-			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 	}
 
 	std::string EthDot3Layer::toString() const

Packet++/src/EthLayer.cpp

@@ -39,35 +39,37 @@ namespace pcpp
 		switch (be16toh(hdr->etherType))
 		{
 		case PCPP_ETHERTYPE_IP:
-			tryConstructNextLayerWithFallback<IPv4Layer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<IPv4Layer, PayloadLayer>(payload, payloadLen, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_IPV6:
-			tryConstructNextLayerWithFallback<IPv6Layer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<IPv6Layer, PayloadLayer>(payload, payloadLen, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_ARP:
-			tryConstructNextLayerWithFallback<ArpLayer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<ArpLayer, PayloadLayer>(payload, payloadLen, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_VLAN:
 		case PCPP_ETHERTYPE_IEEE_802_1AD:
-			tryConstructNextLayerWithFallback<VlanLayer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<VlanLayer, PayloadLayer>(payload, payloadLen, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_PPPOES:
-			tryConstructNextLayerWithFallback<PPPoESessionLayer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<PPPoESessionLayer, PayloadLayer>(payload, payloadLen,
+			                                                                   getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_PPPOED:
-			tryConstructNextLayerWithFallback<PPPoEDiscoveryLayer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<PPPoEDiscoveryLayer, PayloadLayer>(payload, payloadLen,
+			                                                                     getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_MPLS:
-			tryConstructNextLayerWithFallback<MplsLayer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<MplsLayer, PayloadLayer>(payload, payloadLen, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_WAKE_ON_LAN:
-			tryConstructNextLayerWithFallback<WakeOnLanLayer, PayloadLayer>(payload, payloadLen, m_Packet);
+			tryConstructNextLayerWithFallback<WakeOnLanLayer, PayloadLayer>(payload, payloadLen, getAttachedPacket());
 			break;
 		}
 
 		// If no next layer was constructed, assume it's a payload layer
 		if (!hasNextLayer())
-			constructNextLayer<PayloadLayer>(payload, payloadLen, m_Packet);
+			constructNextLayer<PayloadLayer>(payload, payloadLen, getAttachedPacket());
 	}
 
 	void EthLayer::computeCalculateFields()

Packet++/src/GreLayer.cpp

@@ -206,41 +206,41 @@ namespace pcpp
 		{
 		case PCPP_ETHERTYPE_IP:
 			m_NextLayer = IPv4Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		case PCPP_ETHERTYPE_IPV6:
 			m_NextLayer = IPv6Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		case PCPP_ETHERTYPE_VLAN:
-			m_NextLayer = new VlanLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new VlanLayer(payload, payloadLen, this, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_MPLS:
-			m_NextLayer = new MplsLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new MplsLayer(payload, payloadLen, this, getAttachedPacket());
 			break;
 		case PCPP_ETHERTYPE_PPP:
 			m_NextLayer = PPP_PPTPLayer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new PPP_PPTPLayer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new PPP_PPTPLayer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		case PCPP_ETHERTYPE_ETHBRIDGE:
 			if (EthLayer::isDataValid(payload, payloadLen))
 			{
-				m_NextLayer = new EthLayer(payload, payloadLen, this, m_Packet);
+				m_NextLayer = new EthLayer(payload, payloadLen, this, getAttachedPacket());
 			}
 			else if (EthDot3Layer::isDataValid(payload, payloadLen))
 			{
-				m_NextLayer = new EthDot3Layer(payload, payloadLen, this, m_Packet);
+				m_NextLayer = new EthDot3Layer(payload, payloadLen, this, getAttachedPacket());
 			}
 			else
 			{
-				m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+				m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 			}
 			break;
 		default:
-			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 		}
 	}
 
@@ -576,16 +576,16 @@ namespace pcpp
 		{
 		case PCPP_PPP_IP:
 			m_NextLayer = IPv4Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		case PCPP_PPP_IPV6:
 			m_NextLayer = IPv6Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 			break;
 		default:
-			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 			break;
 		}
 	}

Packet++/src/GtpLayer.cpp

@@ -590,18 +590,18 @@ namespace pcpp
 		if (subProto >= 0x45 && subProto <= 0x4e)
 		{
 			m_NextLayer = IPv4Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 		}
 		else if ((subProto & 0xf0) == 0x60)
 		{
 			m_NextLayer = IPv6Layer::isDataValid(payload, payloadLen)
-			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, m_Packet))
-			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));
+			                  ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, getAttachedPacket()))
+			                  : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, getAttachedPacket()));
 		}
 		else
 		{
-			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, getAttachedPacket());
 		}
 	}
 
@@ -1315,11 +1315,11 @@ namespace pcpp
 
 		if (getHeader()->piggybacking && GtpV2Layer::isDataValid(nextLayerData, nextLayerDataLen))
 		{
-			m_NextLayer = new GtpV2Layer(nextLayerData, nextLayerDataLen, this, m_Packet);
+			m_NextLayer = new GtpV2Layer(nextLayerData, nextLayerDataLen, this, getAttachedPacket());
 		}
 		else
 		{
-			m_NextLayer = new PayloadLayer(nextLayerData, nextLayerDataLen, this, m_Packet);
+			m_NextLayer = new PayloadLayer(nextLayerData, nextLayerDataLen, this, getAttachedPacket());
 		}
 	}