Kernel: Optimize networking code

Remove buffering from network layer and rework loopback interface.
loopback now has a separate recieve thread to allow concurrent sends and
prevent deadlocks

kernel/include/kernel/Networking/ARPTable.h

@@ -31,35 +31,18 @@ namespace Kernel
 
 	public:
 		static BAN::ErrorOr<BAN::UniqPtr<ARPTable>> create();
-		~ARPTable();
 
 		BAN::ErrorOr<BAN::MACAddress> get_mac_from_ipv4(NetworkInterface&, BAN::IPv4Address);
 
-		void add_arp_packet(NetworkInterface&, BAN::ConstByteSpan);
+		BAN::ErrorOr<void> handle_arp_packet(NetworkInterface&, BAN::ConstByteSpan);
 
 	private:
-		ARPTable();
+		ARPTable() = default;
-
-		void packet_handle_task();
-		BAN::ErrorOr<void> handle_arp_packet(NetworkInterface&, const ARPPacket&);
 
 	private:
-		struct PendingArpPacket
+		SpinLock m_arp_table_lock;
-		{
-			NetworkInterface& interface;
-			ARPPacket packet;
-		};
-
-	private:
-		SpinLock m_table_lock;
-		SpinLock m_pending_lock;
-
 		BAN::HashMap<BAN::IPv4Address, BAN::MACAddress> m_arp_table;
 
-		Thread*										m_thread { nullptr };
-		BAN::CircularQueue<PendingArpPacket, 128>	m_pending_packets;
-		ThreadBlocker								m_pending_thread_blocker;
-
 		friend class BAN::UniqPtr<ARPTable>;
 	};
 

kernel/include/kernel/Networking/E1000/E1000.h

@@ -23,14 +23,14 @@ namespace Kernel
 		static BAN::ErrorOr<BAN::RefPtr<E1000>> create(PCI::Device&);
 		~E1000();
 
-		virtual BAN::MACAddress get_mac_address() const override { return m_mac_address; }
+		BAN::MACAddress get_mac_address() const override { return m_mac_address; }
 
-		virtual bool link_up() override { return m_link_up; }
+		bool link_up() override { return m_link_up; }
-		virtual int link_speed() override;
+		int link_speed() override;
 
-		virtual size_t payload_mtu() const override { return E1000_RX_BUFFER_SIZE - sizeof(EthernetHeader); }
+		size_t payload_mtu() const override { return E1000_RX_BUFFER_SIZE - sizeof(EthernetHeader); }
 
-		virtual void handle_irq() final override;
+		void handle_irq() final override;
 
 	protected:
 		E1000(PCI::Device& pci_device)
@@ -45,12 +45,12 @@ namespace Kernel
 		uint32_t read32(uint16_t reg);
 		void write32(uint16_t reg, uint32_t value);
 
-		virtual BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan) override;
+		BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan> payload) override;
 
-		virtual bool can_read_impl() const override { return false; }
+		bool can_read_impl() const override { return false; }
-		virtual bool can_write_impl() const override { return false; }
+		bool can_write_impl() const override { return false; }
-		virtual bool has_error_impl() const override { return false; }
+		bool has_error_impl() const override { return false; }
-		virtual bool has_hungup_impl() const override { return false; }
+		bool has_hungup_impl() const override { return false; }
 
 	private:
 		BAN::ErrorOr<void> read_mac_address();
@@ -61,7 +61,7 @@ namespace Kernel
 		void enable_link();
 		BAN::ErrorOr<void> enable_interrupt();
 
-		void handle_receive();
+		void receive_thread();
 
 	protected:
 		PCI::Device&					m_pci_device;
@@ -75,6 +75,10 @@ namespace Kernel
 		BAN::UniqPtr<DMARegion>	m_tx_descriptor_region;
 		SpinLock m_lock;
 
+		bool m_thread_should_die { false };
+		BAN::Atomic<bool> m_thread_is_dead { true };
+		ThreadBlocker m_thread_blocker;
+
 		BAN::MACAddress	m_mac_address {};
 		bool			m_link_up { false };
 

kernel/include/kernel/Networking/E1000/E1000E.h

@@ -12,8 +12,8 @@ namespace Kernel
 		static BAN::ErrorOr<BAN::RefPtr<E1000E>> create(PCI::Device&);
 
 	protected:
-		virtual void detect_eeprom() override;
+		void detect_eeprom() override;
-		virtual uint32_t eeprom_read(uint8_t addr) override;
+		uint32_t eeprom_read(uint8_t addr) override;
 
 	private:
 		E1000E(PCI::Device& pci_device)

kernel/include/kernel/Networking/IPv4Layer.h

@@ -38,11 +38,10 @@ namespace Kernel
 
 	public:
 		static BAN::ErrorOr<BAN::UniqPtr<IPv4Layer>> create();
-		~IPv4Layer();
 
 		ARPTable& arp_table() { return *m_arp_table; }
 
-		void add_ipv4_packet(NetworkInterface&, BAN::ConstByteSpan);
+		BAN::ErrorOr<void> handle_ipv4_packet(NetworkInterface&, BAN::ConstByteSpan);
 
 		virtual void unbind_socket(uint16_t port) override;
 		virtual BAN::ErrorOr<void> bind_socket_with_target(BAN::RefPtr<NetworkSocket>, const sockaddr* target_address, socklen_t target_address_len) override;
@@ -55,35 +54,15 @@ namespace Kernel
 		virtual size_t header_size() const override { return sizeof(IPv4Header); }
 
 	private:
-		IPv4Layer();
+		IPv4Layer() = default;
-
-		void add_ipv4_header(BAN::ByteSpan packet, BAN::IPv4Address src_ipv4, BAN::IPv4Address dst_ipv4, uint8_t protocol) const;
 
 		BAN::ErrorOr<in_port_t> find_free_port();
 
-		void packet_handle_task();
-		BAN::ErrorOr<void> handle_ipv4_packet(NetworkInterface&, BAN::ByteSpan);
-
 	private:
-		struct PendingIPv4Packet
+		BAN::UniqPtr<ARPTable> m_arp_table;
-		{
-			NetworkInterface& interface;
-		};
 
-	private:
+		RecursiveSpinLock m_bound_socket_lock;
-		RecursiveSpinLock		m_bound_socket_lock;
+		BAN::HashMap<int, BAN::WeakPtr<NetworkSocket>> m_bound_sockets;
-
-		BAN::UniqPtr<ARPTable>	m_arp_table;
-		Thread*					m_thread { nullptr };
-
-		static constexpr size_t pending_packet_buffer_size = 128 * PAGE_SIZE;
-		BAN::UniqPtr<VirtualRange>					m_pending_packet_buffer;
-		BAN::CircularQueue<PendingIPv4Packet, 128>	m_pending_packets;
-		ThreadBlocker									m_pending_thread_blocker;
-		SpinLock									m_pending_lock;
-		size_t										m_pending_total_size { 0 };
-
-		BAN::HashMap<int, BAN::WeakPtr<NetworkSocket>>	m_bound_sockets;
 
 		friend class BAN::UniqPtr<IPv4Layer>;
 	};

kernel/include/kernel/Networking/Loopback.h

@@ -9,6 +9,7 @@ namespace Kernel
 	{
 	public:
 		static constexpr size_t buffer_size = BAN::numeric_limits<uint16_t>::max() + 1;
+		static constexpr size_t buffer_count = 32;
 
 	public:
 		static BAN::ErrorOr<BAN::RefPtr<LoopbackInterface>> create();
@@ -24,8 +25,9 @@ namespace Kernel
 		LoopbackInterface()
 			: NetworkInterface(Type::Loopback)
 		{}
+		~LoopbackInterface();
 
-		BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan) override;
+		BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan> payload) override;
 
 		bool can_read_impl() const override { return false; }
 		bool can_write_impl() const override { return false; }
@@ -33,8 +35,27 @@ namespace Kernel
 		bool has_hungup_impl() const override { return false; }
 
 	private:
-		SpinLock m_buffer_lock;
+		void receive_thread();
+
+	private:
+		struct Descriptor
+		{
+			uint8_t* addr;
+			uint32_t size;
+			uint8_t state;
+		};
+
+	private:
+		Mutex m_buffer_lock;
 		BAN::UniqPtr<VirtualRange> m_buffer;
+
+		uint32_t m_buffer_tail { 0 };
+		uint32_t m_buffer_head { 0 };
+		Descriptor m_descriptors[buffer_count] {};
+
+		bool m_thread_should_die { false };
+		BAN::Atomic<bool> m_thread_is_dead { true };
+		ThreadBlocker m_thread_blocker;
 	};
 
 }

kernel/include/kernel/Networking/NetworkInterface.h

@@ -60,7 +60,11 @@ namespace Kernel
 		virtual dev_t rdev() const override { return m_rdev; }
 		virtual BAN::StringView name() const override { return m_name; }
 
-		virtual BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan) = 0;
+		BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan payload)
+		{
+			return send_bytes(destination, protocol, { &payload, 1 });
+		}
+		virtual BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan> payload) = 0;
 
 	private:
 		const Type m_type;

kernel/include/kernel/Networking/NetworkLayer.h

@@ -11,7 +11,7 @@ namespace Kernel
 		BAN::IPv4Address src_ipv4				{ 0 };
 		BAN::IPv4Address dst_ipv4				{ 0 };
 		BAN::NetworkEndian<uint16_t> protocol	{ 0 };
-		BAN::NetworkEndian<uint16_t> extra		{ 0 };
+		BAN::NetworkEndian<uint16_t> length		{ 0 };
 	};
 	static_assert(sizeof(PseudoHeader) == 12);
 
@@ -36,6 +36,7 @@ namespace Kernel
 		NetworkLayer() = default;
 	};
 
-	uint16_t calculate_internet_checksum(BAN::ConstByteSpan packet, const PseudoHeader& pseudo_header);
+	uint16_t calculate_internet_checksum(BAN::ConstByteSpan buffer);
+	uint16_t calculate_internet_checksum(BAN::Span<const BAN::ConstByteSpan> buffers);
 
 }

kernel/include/kernel/Networking/NetworkSocket.h

@@ -32,7 +32,7 @@ namespace Kernel
 		BAN::ErrorOr<BAN::RefPtr<NetworkInterface>> interface(const sockaddr* target, socklen_t target_len);
 
 		virtual size_t protocol_header_size() const = 0;
-		virtual void add_protocol_header(BAN::ByteSpan packet, uint16_t dst_port, PseudoHeader) = 0;
+		virtual void get_protocol_header(BAN::ByteSpan header, BAN::ConstByteSpan payload, uint16_t dst_port, PseudoHeader) = 0;
 		virtual NetworkProtocol protocol() const = 0;
 
 		virtual void receive_packet(BAN::ConstByteSpan, const sockaddr* sender, socklen_t sender_len) = 0;

kernel/include/kernel/Networking/RTL8169/RTL8169.h

@@ -29,9 +29,11 @@ namespace Kernel
 			: NetworkInterface(Type::Ethernet)
 			, m_pci_device(pci_device)
 		{ }
+		~RTL8169();
+
 		BAN::ErrorOr<void> initialize();
 
-		virtual BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan) override;
+		virtual BAN::ErrorOr<void> send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan>) override;
 
 		virtual bool can_read_impl() const override { return false; }
 		virtual bool can_write_impl() const override { return false; }
@@ -47,7 +49,7 @@ namespace Kernel
 		void enable_link();
 		BAN::ErrorOr<void> enable_interrupt();
 
-		void handle_receive();
+		void receive_thread();
 
 	protected:
 		PCI::Device&					m_pci_device;
@@ -63,6 +65,9 @@ namespace Kernel
 		BAN::UniqPtr<DMARegion>	m_tx_descriptor_region;
 
 		SpinLock m_lock;
+
+		bool m_thread_should_die { false };
+		BAN::Atomic<bool> m_thread_is_dead { true };
 		ThreadBlocker m_thread_blocker;
 
 		uint32_t m_rx_current { 0 };

kernel/include/kernel/Networking/TCPSocket.h

@@ -50,30 +50,30 @@ namespace Kernel
 		static BAN::ErrorOr<BAN::RefPtr<TCPSocket>> create(NetworkLayer&, const Info&);
 		~TCPSocket();
 
-		virtual NetworkProtocol protocol() const override { return NetworkProtocol::TCP; }
+		NetworkProtocol protocol() const override { return NetworkProtocol::TCP; }
 
-		virtual size_t protocol_header_size() const override { return sizeof(TCPHeader) + m_tcp_options_bytes; }
+		size_t protocol_header_size() const override { return sizeof(TCPHeader) + m_tcp_options_bytes; }
-		virtual void add_protocol_header(BAN::ByteSpan packet, uint16_t dst_port, PseudoHeader) override;
+		void get_protocol_header(BAN::ByteSpan header, BAN::ConstByteSpan payload, uint16_t dst_port, PseudoHeader) override;
 
 	protected:
-		virtual BAN::ErrorOr<long> accept_impl(sockaddr*, socklen_t*, int) override;
+		BAN::ErrorOr<long> accept_impl(sockaddr*, socklen_t*, int) override;
-		virtual BAN::ErrorOr<void> connect_impl(const sockaddr*, socklen_t) override;
+		BAN::ErrorOr<void> connect_impl(const sockaddr*, socklen_t) override;
-		virtual BAN::ErrorOr<void> listen_impl(int) override;
+		BAN::ErrorOr<void> listen_impl(int) override;
-		virtual BAN::ErrorOr<void> bind_impl(const sockaddr*, socklen_t) override;
+		BAN::ErrorOr<void> bind_impl(const sockaddr*, socklen_t) override;
-		virtual BAN::ErrorOr<size_t> recvmsg_impl(msghdr& message, int flags) override;
+		BAN::ErrorOr<size_t> recvmsg_impl(msghdr& message, int flags) override;
-		virtual BAN::ErrorOr<size_t> sendmsg_impl(const msghdr& message, int flags) override;
+		BAN::ErrorOr<size_t> sendmsg_impl(const msghdr& message, int flags) override;
-		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override;
+		BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override;
-		virtual BAN::ErrorOr<void> getsockopt_impl(int, int, void*, socklen_t*) override;
+		BAN::ErrorOr<void> getsockopt_impl(int, int, void*, socklen_t*) override;
-		virtual BAN::ErrorOr<void> setsockopt_impl(int, int, const void*, socklen_t) override;
+		BAN::ErrorOr<void> setsockopt_impl(int, int, const void*, socklen_t) override;
 
-		virtual BAN::ErrorOr<long> ioctl_impl(int, void*) override;
+		BAN::ErrorOr<long> ioctl_impl(int, void*) override;
 
-		virtual void receive_packet(BAN::ConstByteSpan, const sockaddr* sender, socklen_t sender_len) override;
+		void receive_packet(BAN::ConstByteSpan, const sockaddr* sender, socklen_t sender_len) override;
 
-		virtual bool can_read_impl() const override;
+		bool can_read_impl() const override;
-		virtual bool can_write_impl() const override;
+		bool can_write_impl() const override;
-		virtual bool has_error_impl() const override { return false; }
+		bool has_error_impl() const override { return false; }
-		virtual bool has_hungup_impl() const override;
+		bool has_hungup_impl() const override;
 
 	private:
 		enum class State
@@ -181,6 +181,7 @@ namespace Kernel
 		bool m_no_delay { false };
 
 		bool m_should_send_ack { false };
+		bool m_should_send_zero_window { false };
 
 		uint64_t m_time_wait_start_ms { 0 };
 

kernel/include/kernel/Networking/UDPSocket.h

@@ -25,28 +25,28 @@ namespace Kernel
 	public:
 		static BAN::ErrorOr<BAN::RefPtr<UDPSocket>> create(NetworkLayer&, const Socket::Info&);
 
-		virtual NetworkProtocol protocol() const override { return NetworkProtocol::UDP; }
+		NetworkProtocol protocol() const override { return NetworkProtocol::UDP; }
 
-		virtual size_t protocol_header_size() const override { return sizeof(UDPHeader); }
+		size_t protocol_header_size() const override { return sizeof(UDPHeader); }
-		virtual void add_protocol_header(BAN::ByteSpan packet, uint16_t dst_port, PseudoHeader) override;
+		void get_protocol_header(BAN::ByteSpan header, BAN::ConstByteSpan payload, uint16_t dst_port, PseudoHeader) override;
 
 	protected:
-		virtual void receive_packet(BAN::ConstByteSpan, const sockaddr* sender, socklen_t sender_len) override;
+		void receive_packet(BAN::ConstByteSpan, const sockaddr* sender, socklen_t sender_len) override;
 
-		virtual BAN::ErrorOr<void> connect_impl(const sockaddr*, socklen_t) override;
+		BAN::ErrorOr<void> connect_impl(const sockaddr*, socklen_t) override;
-		virtual BAN::ErrorOr<void> bind_impl(const sockaddr* address, socklen_t address_len) override;
+		BAN::ErrorOr<void> bind_impl(const sockaddr* address, socklen_t address_len) override;
-		virtual BAN::ErrorOr<size_t> recvmsg_impl(msghdr& message, int flags) override;
+		BAN::ErrorOr<size_t> recvmsg_impl(msghdr& message, int flags) override;
-		virtual BAN::ErrorOr<size_t> sendmsg_impl(const msghdr& message, int flags) override;
+		BAN::ErrorOr<size_t> sendmsg_impl(const msghdr& message, int flags) override;
-		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override { return BAN::Error::from_errno(ENOTCONN); }
+		BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override { return BAN::Error::from_errno(ENOTCONN); }
-		virtual BAN::ErrorOr<void> getsockopt_impl(int, int, void*, socklen_t*) override;
+		BAN::ErrorOr<void> getsockopt_impl(int, int, void*, socklen_t*) override;
-		virtual BAN::ErrorOr<void> setsockopt_impl(int, int, const void*, socklen_t) override;
+		BAN::ErrorOr<void> setsockopt_impl(int, int, const void*, socklen_t) override;
 
-		virtual BAN::ErrorOr<long> ioctl_impl(int, void*) override;
+		BAN::ErrorOr<long> ioctl_impl(int, void*) override;
 
-		virtual bool can_read_impl() const override { return !m_packets.empty(); }
+		bool can_read_impl() const override { return !m_packets.empty(); }
-		virtual bool can_write_impl() const override { return true; }
+		bool can_write_impl() const override { return true; }
-		virtual bool has_error_impl() const override { return false; }
+		bool has_error_impl() const override { return false; }
-		virtual bool has_hungup_impl() const override { return false; }
+		bool has_hungup_impl() const override { return false; }
 
 	private:
 		UDPSocket(NetworkLayer&, const Socket::Info&);

kernel/kernel/Networking/ARPTable.cpp

@@ -17,27 +17,7 @@ namespace Kernel
 
 	BAN::ErrorOr<BAN::UniqPtr<ARPTable>> ARPTable::create()
 	{
-		auto arp_table = TRY(BAN::UniqPtr<ARPTable>::create());
+		return TRY(BAN::UniqPtr<ARPTable>::create());
-		arp_table->m_thread = TRY(Thread::create_kernel(
-			[](void* arp_table_ptr)
-			{
-				auto& arp_table = *reinterpret_cast<ARPTable*>(arp_table_ptr);
-				arp_table.packet_handle_task();
-			}, arp_table.ptr()
-		));
-		TRY(Processor::scheduler().add_thread(arp_table->m_thread));
-		return arp_table;
-	}
-
-	ARPTable::ARPTable()
-	{
-	}
-
-	ARPTable::~ARPTable()
-	{
-		if (m_thread)
-			m_thread->add_signal(SIGKILL, {});
-		m_thread = nullptr;
 	}
 
 	BAN::ErrorOr<BAN::MACAddress> ARPTable::get_mac_from_ipv4(NetworkInterface& interface, BAN::IPv4Address ipv4_address)
@@ -64,7 +44,7 @@ namespace Kernel
 			ipv4_address = interface.get_gateway();
 
 		{
-			SpinLockGuard _(m_table_lock);
+			SpinLockGuard _(m_arp_table_lock);
 			auto it = m_arp_table.find(ipv4_address);
 			if (it != m_arp_table.end())
 				return it->value;
@@ -87,7 +67,7 @@ namespace Kernel
 		while (SystemTimer::get().ms_since_boot() < timeout)
 		{
 			{
-				SpinLockGuard _(m_table_lock);
+				SpinLockGuard _(m_arp_table_lock);
 				auto it = m_arp_table.find(ipv4_address);
 				if (it != m_arp_table.end())
 					return it->value;
@@ -98,8 +78,16 @@ namespace Kernel
 		return BAN::Error::from_errno(ETIMEDOUT);
 	}
 
-	BAN::ErrorOr<void> ARPTable::handle_arp_packet(NetworkInterface& interface, const ARPPacket& packet)
+	BAN::ErrorOr<void> ARPTable::handle_arp_packet(NetworkInterface& interface, BAN::ConstByteSpan buffer)
 	{
+		if (buffer.size() < sizeof(ARPPacket))
+		{
+			dwarnln_if(DEBUG_ARP, "Too small ARP packet");
+			return {};
+		}
+
+		const auto& packet = buffer.as<const ARPPacket>();
+
 		if (packet.ptype != EtherType::IPv4)
 		{
 			dprintln("Non IPv4 arp packet?");
@@ -112,23 +100,24 @@ namespace Kernel
 			{
 				if (packet.tpa == interface.get_ipv4_address())
 				{
-					ARPPacket arp_reply;
+					const ARPPacket arp_reply {
-					arp_reply.htype = 0x0001;
+						.htype = 0x0001,
-					arp_reply.ptype = EtherType::IPv4;
+						.ptype = EtherType::IPv4,
-					arp_reply.hlen = 0x06;
+						.hlen = 0x06,
-					arp_reply.plen = 0x04;
+						.plen = 0x04,
-					arp_reply.oper = ARPOperation::Reply;
+						.oper = ARPOperation::Reply,
-					arp_reply.sha = interface.get_mac_address();
+						.sha = interface.get_mac_address(),
-					arp_reply.spa = interface.get_ipv4_address();
+						.spa = interface.get_ipv4_address(),
-					arp_reply.tha = packet.sha;
+						.tha = packet.sha,
-					arp_reply.tpa = packet.spa;
+						.tpa = packet.spa,
+					};
 					TRY(interface.send_bytes(packet.sha, EtherType::ARP, BAN::ConstByteSpan::from(arp_reply)));
 				}
 				break;
 			}
 			case ARPOperation::Reply:
 			{
-				SpinLockGuard _(m_table_lock);
+				SpinLockGuard _(m_arp_table_lock);
 				auto it = m_arp_table.find(packet.spa);
 
 				if (it != m_arp_table.end())
@@ -154,48 +143,4 @@ namespace Kernel
 		return {};
 	}
 
-	void ARPTable::packet_handle_task()
-	{
-		for (;;)
-		{
-			PendingArpPacket pending = ({
-				SpinLockGuard guard(m_pending_lock);
-				while (m_pending_packets.empty())
-				{
-					SpinLockGuardAsMutex smutex(guard);
-					m_pending_thread_blocker.block_indefinite(&smutex);
-				}
-
-				auto packet = m_pending_packets.front();
-				m_pending_packets.pop();
-
-				packet;
-			});
-
-			if (auto ret = handle_arp_packet(pending.interface, pending.packet); ret.is_error())
-				dwarnln("{}", ret.error());
-		}
-	}
-
-	void ARPTable::add_arp_packet(NetworkInterface& interface, BAN::ConstByteSpan buffer)
-	{
-		if (buffer.size() < sizeof(ARPPacket))
-		{
-			dwarnln_if(DEBUG_ARP, "ARP packet too small");
-			return;
-		}
-		auto& arp_packet = buffer.as<const ARPPacket>();
-
-		SpinLockGuard _(m_pending_lock);
-
-		if (m_pending_packets.full())
-		{
-			dwarnln_if(DEBUG_ARP, "ARP packet queue full");
-			return;
-		}
-
-		m_pending_packets.push({ .interface = interface, .packet = arp_packet });
-		m_pending_thread_blocker.unblock();
-	}
-
 }

kernel/kernel/Networking/E1000/E1000.cpp

@@ -1,6 +1,7 @@
 #include <kernel/IDT.h>
 #include <kernel/InterruptController.h>
 #include <kernel/IO.h>
+#include <kernel/Lock/SpinLockAsMutex.h>
 #include <kernel/Memory/PageTable.h>
 #include <kernel/MMIO.h>
 #include <kernel/Networking/E1000/E1000.h>
@@ -57,6 +58,11 @@ namespace Kernel
 
 	E1000::~E1000()
 	{
+		m_thread_should_die = true;
+		m_thread_blocker.unblock();
+
+		while (!m_thread_is_dead)
+			Processor::yield();
 	}
 
 	BAN::ErrorOr<void> E1000::initialize()
@@ -84,6 +90,16 @@ namespace Kernel
 			dprintln("  link speed: {} Mbps", speed);
 		}
 
+		auto* thread = TRY(Thread::create_kernel([](void* e1000_ptr) {
+			static_cast<E1000*>(e1000_ptr)->receive_thread();
+		}, this));
+		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
+		{
+			delete thread;
+			return ret.release_error();
+		}
+		m_thread_is_dead = false;
+
 		return {};
 	}
 
@@ -259,10 +275,8 @@ namespace Kernel
 		return {};
 	}
 
-	BAN::ErrorOr<void> E1000::send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan buffer)
+	BAN::ErrorOr<void> E1000::send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan> payload)
 	{
-		ASSERT(buffer.size() + sizeof(EthernetHeader) <= E1000_TX_BUFFER_SIZE);
-
 		SpinLockGuard _(m_lock);
 
 		size_t tx_current = read32(REG_TDT) % E1000_TX_DESCRIPTOR_COUNT;
@@ -274,48 +288,75 @@ namespace Kernel
 		ethernet_header.src_mac = get_mac_address();
 		ethernet_header.ether_type = protocol;
 
-		memcpy(tx_buffer + sizeof(EthernetHeader), buffer.data(), buffer.size());
+		size_t packet_size = sizeof(EthernetHeader);
+		for (const auto& buffer : payload)
+		{
+			ASSERT(packet_size + buffer.size() < E1000_TX_BUFFER_SIZE);
+			memcpy(tx_buffer + packet_size, buffer.data(), buffer.size());
+			packet_size += buffer.size();
+		}
 
 		auto& descriptor = reinterpret_cast<volatile e1000_tx_desc*>(m_tx_descriptor_region->vaddr())[tx_current];
-		descriptor.length = sizeof(EthernetHeader) + buffer.size();
+		descriptor.length = packet_size;
 		descriptor.status = 0;
 		descriptor.cmd = CMD_EOP | CMD_IFCS | CMD_RS;
 
+		// FIXME: there isnt really any reason to wait for transmission
 		write32(REG_TDT, (tx_current + 1) % E1000_TX_DESCRIPTOR_COUNT);
 		while (descriptor.status == 0)
 			continue;
 
-		dprintln_if(DEBUG_E1000, "sent {} bytes", sizeof(EthernetHeader) + buffer.size());
+		dprintln_if(DEBUG_E1000, "sent {} bytes", packet_size);
 
 		return {};
 	}
 
+	void E1000::receive_thread()
+	{
+		SpinLockGuard _(m_lock);
+
+		while (!m_thread_should_die)
+		{
+			for (;;)
+			{
+				const uint32_t rx_current = (read32(REG_RDT0) + 1) % E1000_RX_DESCRIPTOR_COUNT;
+
+				auto& descriptor = reinterpret_cast<volatile e1000_rx_desc*>(m_rx_descriptor_region->vaddr())[rx_current];
+				if (!(descriptor.status & 1))
+					break;
+				ASSERT(descriptor.length <= E1000_RX_BUFFER_SIZE);
+
+				dprintln_if(DEBUG_E1000, "got {} bytes", (uint16_t)descriptor.length);
+
+				m_lock.unlock(InterruptState::Enabled);
+
+				NetworkManager::get().on_receive(*this, BAN::ConstByteSpan {
+					reinterpret_cast<const uint8_t*>(m_rx_buffer_region->vaddr() + rx_current * E1000_RX_BUFFER_SIZE),
+					descriptor.length
+				});
+
+				m_lock.lock();
+
+				descriptor.status = 0;
+				write32(REG_RDT0, rx_current);
+			}
+
+			SpinLockAsMutex smutex(m_lock, InterruptState::Enabled);
+			m_thread_blocker.block_indefinite(&smutex);
+		}
+
+		m_thread_is_dead = true;
+	}
+
 	void E1000::handle_irq()
 	{
 		const uint32_t icr = read32(REG_ICR);
-		if (!(icr & (ICR_RxQ0 | ICR_RXT0)))
-			return;
 		write32(REG_ICR, icr);
 
-		SpinLockGuard _(m_lock);
+		if (icr & (ICR_RxQ0 | ICR_RXT0))
-
+		{
-		for (;;) {
+			SpinLockGuard _(m_lock);
-			uint32_t rx_current = (read32(REG_RDT0) + 1) % E1000_RX_DESCRIPTOR_COUNT;
+			m_thread_blocker.unblock();
-
-			auto& descriptor = reinterpret_cast<volatile e1000_rx_desc*>(m_rx_descriptor_region->vaddr())[rx_current];
-			if (!(descriptor.status & 1))
-				break;
-			ASSERT(descriptor.length <= E1000_RX_BUFFER_SIZE);
-
-			dprintln_if(DEBUG_E1000, "got {} bytes", (uint16_t)descriptor.length);
-
-			NetworkManager::get().on_receive(*this, BAN::ConstByteSpan {
-				reinterpret_cast<const uint8_t*>(m_rx_buffer_region->vaddr() + rx_current * E1000_RX_BUFFER_SIZE),
-				descriptor.length
-			});
-
-			descriptor.status = 0;
-			write32(REG_RDT0, rx_current);
 		}
 	}
 

kernel/kernel/Networking/IPv4Layer.cpp

@@ -21,50 +21,26 @@ namespace Kernel
 	BAN::ErrorOr<BAN::UniqPtr<IPv4Layer>> IPv4Layer::create()
 	{
 		auto ipv4_manager = TRY(BAN::UniqPtr<IPv4Layer>::create());
-		ipv4_manager->m_thread = TRY(Thread::create_kernel(
-			[](void* ipv4_manager_ptr)
-			{
-				auto& ipv4_manager = *reinterpret_cast<IPv4Layer*>(ipv4_manager_ptr);
-				ipv4_manager.packet_handle_task();
-			}, ipv4_manager.ptr()
-		));
-		TRY(Processor::scheduler().add_thread(ipv4_manager->m_thread));
-		ipv4_manager->m_pending_packet_buffer = TRY(VirtualRange::create_to_vaddr_range(
-			PageTable::kernel(),
-			KERNEL_OFFSET,
-			~(uintptr_t)0,
-			pending_packet_buffer_size,
-			PageTable::Flags::ReadWrite | PageTable::Flags::Present,
-			true, false
-		));
 		ipv4_manager->m_arp_table = TRY(ARPTable::create());
 		return ipv4_manager;
 	}
 
-	IPv4Layer::IPv4Layer()
+	static IPv4Header get_ipv4_header(size_t packet_size, BAN::IPv4Address src_ipv4, BAN::IPv4Address dst_ipv4, uint8_t protocol)
-	{ }
-
-	IPv4Layer::~IPv4Layer()
 	{
-		if (m_thread)
+		IPv4Header header {
-			m_thread->add_signal(SIGKILL, {});
+			.version_IHL    = 0x45,
-		m_thread = nullptr;
+			.DSCP_ECN       = 0x00,
-	}
+			.total_length   = packet_size,
-
+			.identification = 1,
-	void IPv4Layer::add_ipv4_header(BAN::ByteSpan packet, BAN::IPv4Address src_ipv4, BAN::IPv4Address dst_ipv4, uint8_t protocol) const
+			.flags_frament  = 0x00,
-	{
+			.time_to_live   = 0x40,
-		auto& header = packet.as<IPv4Header>();
+			.protocol       = protocol,
-		header.version_IHL		= 0x45;
+			.checksum       = 0,
-		header.DSCP_ECN			= 0x00;
+			.src_address    = src_ipv4,
-		header.total_length		= packet.size();
+			.dst_address    = dst_ipv4,
-		header.identification	= 1;
+		};
-		header.flags_frament	= 0x00;
+		header.checksum = calculate_internet_checksum(BAN::ConstByteSpan::from(header));
-		header.time_to_live		= 0x40;
+		return header;
-		header.protocol			= protocol;
-		header.src_address		= src_ipv4;
-		header.dst_address		= dst_ipv4;
-		header.checksum			= 0;
-		header.checksum			= calculate_internet_checksum(BAN::ConstByteSpan::from(header), {});
 	}
 
 	void IPv4Layer::unbind_socket(uint16_t port)
@@ -204,7 +180,7 @@ namespace Kernel
 		return {};
 	}
 
-	BAN::ErrorOr<size_t> IPv4Layer::sendto(NetworkSocket& socket, BAN::ConstByteSpan buffer, const sockaddr* address, socklen_t address_len)
+	BAN::ErrorOr<size_t> IPv4Layer::sendto(NetworkSocket& socket, BAN::ConstByteSpan payload, const sockaddr* address, socklen_t address_len)
 	{
 		if (address->sa_family != AF_INET)
 			return BAN::Error::from_errno(EINVAL);
@@ -233,43 +209,61 @@ namespace Kernel
 				return BAN::Error::from_errno(EADDRNOTAVAIL);
 		}
 
-		BAN::Vector<uint8_t> packet_buffer;
+		const auto ipv4_header = get_ipv4_header(
-		TRY(packet_buffer.resize(buffer.size() + sizeof(IPv4Header) + socket.protocol_header_size()));
+			sizeof(IPv4Header) + socket.protocol_header_size() + payload.size(),
-		auto packet = BAN::ByteSpan { packet_buffer.span() };
-
-		auto pseudo_header = PseudoHeader {
-			.src_ipv4 = interface->get_ipv4_address(),
-			.dst_ipv4 = dst_ipv4,
-			.protocol = socket.protocol()
-		};
-
-		memcpy(
-			packet.slice(sizeof(IPv4Header)).slice(socket.protocol_header_size()).data(),
-			buffer.data(),
-			buffer.size()
-		);
-		socket.add_protocol_header(
-			packet.slice(sizeof(IPv4Header)),
-			dst_port,
-			pseudo_header
-		);
-		add_ipv4_header(
-			packet,
 			interface->get_ipv4_address(),
 			dst_ipv4,
 			socket.protocol()
 		);
 
-		TRY(interface->send_bytes(dst_mac, EtherType::IPv4, packet));
+		const auto pseudo_header = PseudoHeader {
+			.src_ipv4 = interface->get_ipv4_address(),
+			.dst_ipv4 = dst_ipv4,
+			.protocol = socket.protocol(),
+			.length = socket.protocol_header_size() + payload.size()
+		};
 
-		return buffer.size();
+		uint8_t protocol_header_buffer[32];
+		ASSERT(socket.protocol_header_size() < sizeof(protocol_header_buffer));
+
+		auto protocol_header = BAN::ByteSpan::from(protocol_header_buffer).slice(0, socket.protocol_header_size());
+		socket.get_protocol_header(protocol_header, payload, dst_port, pseudo_header);
+
+		BAN::ConstByteSpan buffers[] {
+			BAN::ConstByteSpan::from(ipv4_header),
+			protocol_header,
+			payload,
+		};
+
+		TRY(interface->send_bytes(dst_mac, EtherType::IPv4, { buffers, sizeof(buffers) / sizeof(*buffers) }));
+
+		return payload.size();
 	}
 
-	BAN::ErrorOr<void> IPv4Layer::handle_ipv4_packet(NetworkInterface& interface, BAN::ByteSpan packet)
+	BAN::ErrorOr<void> IPv4Layer::handle_ipv4_packet(NetworkInterface& interface, BAN::ConstByteSpan packet)
 	{
-		ASSERT(packet.size() >= sizeof(IPv4Header));
+		if (packet.size() < sizeof(IPv4Header))
+		{
+			dwarnln_if(DEBUG_IPV4, "Too small IPv4 packet");
+			return {};
+		}
+
 		auto& ipv4_header = packet.as<const IPv4Header>();
-		auto ipv4_data = packet.slice(sizeof(IPv4Header));
+		if (calculate_internet_checksum(BAN::ConstByteSpan::from(ipv4_header)) != 0)
+		{
+			dwarnln_if(DEBUG_IPV4, "IPv4 packet checksum failed");
+			return {};
+		}
+		if (ipv4_header.total_length > packet.size() || ipv4_header.total_length > interface.payload_mtu() || ipv4_header.total_length < sizeof(IPv4Header))
+		{
+			if (ipv4_header.flags_frament & IPv4Flags::DF)
+				dwarnln_if(DEBUG_IPV4, "Invalid IPv4 packet");
+			else
+				dwarnln_if(DEBUG_IPV4, "IPv4 fragmentation not supported");
+			return {};
+		}
+
+		auto ipv4_data = packet.slice(0, ipv4_header.total_length).slice(sizeof(IPv4Header));
 
 		auto src_ipv4 = ipv4_header.src_address;
 
@@ -292,14 +286,33 @@ namespace Kernel
 					{
 						auto dst_mac = TRY(m_arp_table->get_mac_from_ipv4(interface, src_ipv4));
 
-						auto& reply_icmp_header = ipv4_data.as<ICMPHeader>();
+						auto send_ipv4_header = get_ipv4_header(
-						reply_icmp_header.type = ICMPType::EchoReply;
+							ipv4_data.size(),
-						reply_icmp_header.checksum = 0;
+							interface.get_ipv4_address(),
-						reply_icmp_header.checksum = calculate_internet_checksum(ipv4_data, {});
+							src_ipv4,
+							NetworkProtocol::ICMP
+						);
 
-						add_ipv4_header(packet, interface.get_ipv4_address(), src_ipv4, NetworkProtocol::ICMP);
+						ICMPHeader send_icmp_header {
+							.type = ICMPType::EchoReply,
+							.code = icmp_header.code,
+							.checksum = 0,
+							.rest = icmp_header.rest,
+						};
+
+						auto send_payload = ipv4_data.slice(sizeof(ICMPHeader));
+
+						const BAN::ConstByteSpan send_buffers[] {
+							BAN::ConstByteSpan::from(send_ipv4_header),
+							BAN::ConstByteSpan::from(send_icmp_header),
+							send_payload
+						};
+						auto send_buffers_span = BAN::Span { send_buffers, sizeof(send_buffers) / sizeof(*send_buffers) };
+
+						send_icmp_header.checksum = calculate_internet_checksum(send_buffers_span.slice(1));
+
+						TRY(interface.send_bytes(dst_mac, EtherType::IPv4, send_buffers_span));
 
-						TRY(interface.send_bytes(dst_mac, EtherType::IPv4, packet));
 						break;
 					}
 					case ICMPType::DestinationUnreachable:
@@ -381,80 +394,4 @@ namespace Kernel
 		return {};
 	}
 
-	void IPv4Layer::packet_handle_task()
-	{
-		for (;;)
-		{
-			PendingIPv4Packet pending = ({
-				SpinLockGuard guard(m_pending_lock);
-				while (m_pending_packets.empty())
-				{
-					SpinLockGuardAsMutex smutex(guard);
-					m_pending_thread_blocker.block_indefinite(&smutex);
-				}
-
-				auto packet = m_pending_packets.front();
-				m_pending_packets.pop();
-
-				packet;
-			});
-
-			uint8_t* buffer_start = reinterpret_cast<uint8_t*>(m_pending_packet_buffer->vaddr());
-			const size_t ipv4_packet_size = reinterpret_cast<const IPv4Header*>(buffer_start)->total_length;
-
-			if (auto ret = handle_ipv4_packet(pending.interface, BAN::ByteSpan(buffer_start, ipv4_packet_size)); ret.is_error())
-				dwarnln_if(DEBUG_IPV4, "{}", ret.error());
-
-			SpinLockGuard _(m_pending_lock);
-			m_pending_total_size -= ipv4_packet_size;
-			if (m_pending_total_size)
-				memmove(buffer_start, buffer_start + ipv4_packet_size, m_pending_total_size);
-		}
-	}
-
-	void IPv4Layer::add_ipv4_packet(NetworkInterface& interface, BAN::ConstByteSpan buffer)
-	{
-		if (buffer.size() < sizeof(IPv4Header))
-		{
-			dwarnln_if(DEBUG_IPV4, "IPv4 packet too small");
-			return;
-		}
-
-		SpinLockGuard _(m_pending_lock);
-
-		if (m_pending_packets.full())
-		{
-			dwarnln_if(DEBUG_IPV4, "IPv4 packet queue full");
-			return;
-		}
-
-		if (m_pending_total_size + buffer.size() > m_pending_packet_buffer->size())
-		{
-			dwarnln_if(DEBUG_IPV4, "IPv4 packet queue full");
-			return;
-		}
-
-		auto& ipv4_header = buffer.as<const IPv4Header>();
-		if (calculate_internet_checksum(BAN::ConstByteSpan::from(ipv4_header), {}) != 0)
-		{
-			dwarnln_if(DEBUG_IPV4, "Invalid IPv4 packet");
-			return;
-		}
-		if (ipv4_header.total_length > buffer.size() || ipv4_header.total_length > interface.payload_mtu())
-		{
-			if (ipv4_header.flags_frament & IPv4Flags::DF)
-				dwarnln_if(DEBUG_IPV4, "Invalid IPv4 packet");
-			else
-				dwarnln_if(DEBUG_IPV4, "IPv4 fragmentation not supported");
-			return;
-		}
-
-		uint8_t* buffer_start = reinterpret_cast<uint8_t*>(m_pending_packet_buffer->vaddr());
-		memcpy(buffer_start + m_pending_total_size, buffer.data(), ipv4_header.total_length);
-		m_pending_total_size += ipv4_header.total_length;
-
-		m_pending_packets.push({ .interface = interface });
-		m_pending_thread_blocker.unblock();
-	}
-
 }

kernel/kernel/Networking/Loopback.cpp

@@ -1,3 +1,4 @@
+#include <kernel/Lock/LockGuard.h>
 #include <kernel/Networking/Loopback.h>
 #include <kernel/Networking/NetworkManager.h>
 
@@ -10,40 +11,121 @@ namespace Kernel
 		if (loopback_ptr == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
 		auto loopback = BAN::RefPtr<LoopbackInterface>::adopt(loopback_ptr);
+
 		loopback->m_buffer = TRY(VirtualRange::create_to_vaddr_range(
 			PageTable::kernel(),
 			KERNEL_OFFSET,
 			BAN::numeric_limits<vaddr_t>::max(),
-			buffer_size,
+			buffer_size * buffer_count,
 			PageTable::Flags::ReadWrite | PageTable::Flags::Present,
 			true, false
 		));
+
+		auto* thread = TRY(Thread::create_kernel([](void* loopback_ptr) {
+			static_cast<LoopbackInterface*>(loopback_ptr)->receive_thread();
+		}, loopback_ptr));
+		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
+		{
+			delete thread;
+			return ret.release_error();
+		}
+		loopback->m_thread_is_dead = false;
+
 		loopback->set_ipv4_address({ 127, 0, 0, 1 });
 		loopback->set_netmask({ 255, 0, 0, 0 });
+
+		for (size_t i = 0; i < buffer_count; i++)
+		{
+			loopback->m_descriptors[i] = {
+				.addr = reinterpret_cast<uint8_t*>(loopback->m_buffer->vaddr()) + i * buffer_size,
+				.size = 0,
+				.state = 0,
+			};
+		}
+
 		return loopback;
 	}
 
-	BAN::ErrorOr<void> LoopbackInterface::send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan buffer)
+	LoopbackInterface::~LoopbackInterface()
 	{
-		ASSERT(buffer.size() + sizeof(EthernetHeader) <= buffer_size);
+		m_thread_should_die = true;
+		m_thread_blocker.unblock();
 
-		SpinLockGuard _(m_buffer_lock);
+		while (!m_thread_is_dead)
+			Processor::yield();
+	}
 
-		uint8_t* buffer_vaddr = reinterpret_cast<uint8_t*>(m_buffer->vaddr());
+	BAN::ErrorOr<void> LoopbackInterface::send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan> payload)
+	{
+		auto& descriptor =
+			[&]() -> Descriptor&
+			{
+				LockGuard _(m_buffer_lock);
+				for (;;)
+				{
+					auto& descriptor = m_descriptors[m_buffer_head];
+					if (descriptor.state == 0)
+					{
+						m_buffer_head = (m_buffer_head + 1) % buffer_count;
+						descriptor.state = 1;
+						return descriptor;
+					}
+					m_thread_blocker.block_indefinite(&m_buffer_lock);
+				}
+			}();
 
-		auto& ethernet_header = *reinterpret_cast<EthernetHeader*>(buffer_vaddr);
+		auto& ethernet_header = *reinterpret_cast<EthernetHeader*>(descriptor.addr);
 		ethernet_header.dst_mac = destination;
 		ethernet_header.src_mac = get_mac_address();
 		ethernet_header.ether_type = protocol;
 
-		memcpy(buffer_vaddr + sizeof(EthernetHeader), buffer.data(), buffer.size());
+		size_t packet_size = sizeof(EthernetHeader);
+		for (const auto& buffer : payload)
+		{
+			ASSERT(packet_size + buffer.size() <= buffer_size);
+			memcpy(descriptor.addr + packet_size, buffer.data(), buffer.size());
+			packet_size += buffer.size();
+		}
 
-		NetworkManager::get().on_receive(*this, BAN::ConstByteSpan {
+		LockGuard _(m_buffer_lock);
-			buffer_vaddr,
+		descriptor.size = packet_size;
-			buffer.size() + sizeof(EthernetHeader)
+		descriptor.state = 2;
-		});
+		m_thread_blocker.unblock();
 
 		return {};
 	}
 
+	void LoopbackInterface::receive_thread()
+	{
+		LockGuard _(m_buffer_lock);
+
+		while (!m_thread_should_die)
+		{
+			for (;;)
+			{
+				auto& descriptor = m_descriptors[m_buffer_tail];
+				if (descriptor.state != 2)
+					break;
+				m_buffer_tail = (m_buffer_tail + 1) % buffer_count;
+
+				m_buffer_lock.unlock();
+
+				NetworkManager::get().on_receive(*this, {
+					descriptor.addr,
+					descriptor.size,
+				});
+
+				m_buffer_lock.lock();
+
+				descriptor.size = 0;
+				descriptor.state = 0;
+				m_thread_blocker.unblock();
+			}
+
+			m_thread_blocker.block_indefinite(&m_buffer_lock);
+		}
+
+		m_thread_is_dead = true;
+	}
+
 }

kernel/kernel/Networking/NetworkLayer.cpp

@@ -3,15 +3,28 @@
 namespace Kernel
 {
 
-	uint16_t calculate_internet_checksum(BAN::ConstByteSpan packet, const PseudoHeader& pseudo_header)
+	uint16_t calculate_internet_checksum(BAN::ConstByteSpan buffer)
+	{
+		return calculate_internet_checksum({ &buffer, 1 });
+	}
+
+	uint16_t calculate_internet_checksum(BAN::Span<const BAN::ConstByteSpan> buffers)
 	{
 		uint32_t checksum = 0;
-		for (size_t i = 0; i < sizeof(pseudo_header) / sizeof(uint16_t); i++)
+
-			checksum += BAN::host_to_network_endian(reinterpret_cast<const uint16_t*>(&pseudo_header)[i]);
+		for (size_t i = 0; i < buffers.size(); i++)
-		for (size_t i = 0; i < packet.size() / sizeof(uint16_t); i++)
+		{
-			checksum += BAN::host_to_network_endian(reinterpret_cast<const uint16_t*>(packet.data())[i]);
+			auto buffer = buffers[i];
-		if (packet.size() % 2)
+
-			checksum += (uint16_t)packet[packet.size() - 1] << 8;
+			const uint16_t* buffer_u16 = reinterpret_cast<const uint16_t*>(buffer.data());
+			for (size_t j = 0; j < buffer.size() / 2; j++)
+				checksum += BAN::host_to_network_endian(buffer_u16[j]);
+			if (buffer.size() % 2 == 0)
+				continue;
+			ASSERT(i == buffers.size() - 1);
+			checksum += buffer[buffer.size() - 1] << 8;
+		}
+
 		while (checksum >> 16)
 			checksum = (checksum >> 16) + (checksum & 0xFFFF);
 		return ~(uint16_t)checksum;

kernel/kernel/Networking/NetworkManager.cpp

@@ -154,18 +154,18 @@ namespace Kernel
 			return;
 		auto ethernet_header = packet.as<const EthernetHeader>();
 
+		auto packet_data = packet.slice(sizeof(EthernetHeader));
+
 		switch (ethernet_header.ether_type)
 		{
 			case EtherType::ARP:
-			{
+				if (auto ret = m_ipv4_layer->arp_table().handle_arp_packet(interface, packet_data); ret.is_error())
-				m_ipv4_layer->arp_table().add_arp_packet(interface, packet.slice(sizeof(EthernetHeader)));
+					dwarnln("ARP: {}", ret.error());
 				break;
-			}
 			case EtherType::IPv4:
-			{
+				if (auto ret = m_ipv4_layer->handle_ipv4_packet(interface, packet_data); ret.is_error())
-				m_ipv4_layer->add_ipv4_packet(interface, packet.slice(sizeof(EthernetHeader)));
+					dwarnln("IPv4; {}", ret.error());
 				break;
-			}
 			default:
 				dprintln_if(DEBUG_ETHERTYPE, "Unknown EtherType 0x{4H}", (uint16_t)ethernet_header.ether_type);
 				break;

kernel/kernel/Networking/RTL8169/RTL8169.cpp

@@ -7,6 +7,9 @@
 namespace Kernel
 {
 
+	// each buffer is 7440 bytes + padding = 8192
+	constexpr size_t s_buffer_size = 8192;
+
 	bool RTL8169::probe(PCI::Device& pci_device)
 	{
 		if (pci_device.vendor_id() != 0x10ec)
@@ -68,9 +71,28 @@ namespace Kernel
 		// lock config registers
 		m_io_bar_region->write8(RTL8169_IO_9346CR, RTL8169_9346CR_MODE_NORMAL);
 
+		auto* thread = TRY(Thread::create_kernel([](void* rtl8169_ptr) {
+			static_cast<RTL8169*>(rtl8169_ptr)->receive_thread();
+		}, this));
+		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
+		{
+			delete thread;
+			return ret.release_error();
+		}
+		m_thread_is_dead = false;
+
 		return {};
 	}
 
+	RTL8169::~RTL8169()
+	{
+		m_thread_should_die = true;
+		m_thread_blocker.unblock();
+
+		while (!m_thread_is_dead)
+			Processor::yield();
+	}
+
 	BAN::ErrorOr<void> RTL8169::reset()
 	{
 		m_io_bar_region->write8(RTL8169_IO_CR, RTL8169_CR_RST);
@@ -85,15 +107,12 @@ namespace Kernel
 
 	BAN::ErrorOr<void> RTL8169::initialize_rx()
 	{
-		// each buffer is 7440 bytes + padding = 8192
+		m_rx_buffer_region = TRY(DMARegion::create(m_rx_descriptor_count * s_buffer_size));
-		constexpr size_t buffer_size = 2 * PAGE_SIZE;
-
-		m_rx_buffer_region = TRY(DMARegion::create(m_rx_descriptor_count * buffer_size));
 		m_rx_descriptor_region = TRY(DMARegion::create(m_rx_descriptor_count * sizeof(RTL8169Descriptor)));
 
 		for (size_t i = 0; i < m_rx_descriptor_count; i++)
 		{
-			const paddr_t rx_buffer_paddr = m_rx_buffer_region->paddr() + i * buffer_size;
+			const paddr_t rx_buffer_paddr = m_rx_buffer_region->paddr() + i * s_buffer_size;
 
 			uint32_t command = 0x1FF8 | RTL8169_DESC_CMD_OWN;
 			if (i == m_rx_descriptor_count - 1)
@@ -120,21 +139,17 @@ namespace Kernel
 		// configure max rx packet size
 		m_io_bar_region->write16(RTL8169_IO_RMS, RTL8169_RMS_MAX);
 
-
 		return {};
 	}
 
 	BAN::ErrorOr<void> RTL8169::initialize_tx()
 	{
-		// each buffer is 7440 bytes + padding = 8192
+		m_tx_buffer_region = TRY(DMARegion::create(m_tx_descriptor_count * s_buffer_size));
-		constexpr size_t buffer_size = 2 * PAGE_SIZE;
-
-		m_tx_buffer_region = TRY(DMARegion::create(m_tx_descriptor_count * buffer_size));
 		m_tx_descriptor_region = TRY(DMARegion::create(m_tx_descriptor_count * sizeof(RTL8169Descriptor)));
 
 		for (size_t i = 0; i < m_tx_descriptor_count; i++)
 		{
-			const paddr_t tx_buffer_paddr = m_tx_buffer_region->paddr() + i * buffer_size;
+			const paddr_t tx_buffer_paddr = m_tx_buffer_region->paddr() + i * s_buffer_size;
 
 			uint32_t command = 0;
 			if (i == m_tx_descriptor_count - 1)
@@ -194,14 +209,8 @@ namespace Kernel
 		return 0;
 	}
 
-	BAN::ErrorOr<void> RTL8169::send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::ConstByteSpan buffer)
+	BAN::ErrorOr<void> RTL8169::send_bytes(BAN::MACAddress destination, EtherType protocol, BAN::Span<const BAN::ConstByteSpan> payload)
 	{
-		constexpr size_t buffer_size = 8192;
-
-		const uint16_t packet_size = sizeof(EthernetHeader) + buffer.size();
-		if (packet_size > buffer_size)
-			return BAN::Error::from_errno(EINVAL);
-
 		if (!link_up())
 			return BAN::Error::from_errno(EADDRNOTAVAIL);
 
@@ -219,14 +228,20 @@ namespace Kernel
 
 		m_lock.unlock(state);
 
-		auto* tx_buffer = reinterpret_cast<uint8_t*>(m_tx_buffer_region->vaddr() + tx_current * buffer_size);
+		auto* tx_buffer = reinterpret_cast<uint8_t*>(m_tx_buffer_region->vaddr() + tx_current * s_buffer_size);
 
 		// write packet
 		auto& ethernet_header = *reinterpret_cast<EthernetHeader*>(tx_buffer);
 		ethernet_header.dst_mac = destination;
 		ethernet_header.src_mac = get_mac_address();
 		ethernet_header.ether_type = protocol;
-		memcpy(tx_buffer + sizeof(EthernetHeader), buffer.data(), buffer.size());
+
+		size_t packet_size = sizeof(EthernetHeader);
+		for (const auto& buffer : payload)
+		{
+			memcpy(tx_buffer + packet_size, buffer.data(), buffer.size());
+			packet_size += buffer.size();
+		}
 
 		// give packet ownership to NIC
 		uint32_t command = packet_size | RTL8169_DESC_CMD_OWN | RTL8169_DESC_CMD_LS | RTL8169_DESC_CMD_FS;
@@ -240,6 +255,50 @@ namespace Kernel
 		return {};
 	}
 
+	void RTL8169::receive_thread()
+	{
+		SpinLockGuard _(m_lock);
+
+		while (!m_thread_should_die)
+		{
+			for (;;)
+			{
+				auto& descriptor = reinterpret_cast<volatile RTL8169Descriptor*>(m_rx_descriptor_region->vaddr())[m_rx_current];
+				if (descriptor.command & RTL8169_DESC_CMD_OWN)
+					break;
+
+				// packet buffer can only hold single packet, so we should not receive any multi-descriptor packets
+				ASSERT((descriptor.command & RTL8169_DESC_CMD_LS) && (descriptor.command & RTL8169_DESC_CMD_FS));
+
+				const uint16_t packet_length = descriptor.command & 0x3FFF;
+				if (packet_length > s_buffer_size)
+					dwarnln("Got {} bytes to {} byte buffer", packet_length, s_buffer_size);
+				else if (descriptor.command & (1u << 21))
+					; // descriptor has an error
+				else
+				{
+					m_lock.unlock(InterruptState::Enabled);
+
+					NetworkManager::get().on_receive(*this, BAN::ConstByteSpan {
+						reinterpret_cast<const uint8_t*>(m_rx_buffer_region->vaddr() + m_rx_current * s_buffer_size),
+						packet_length
+					});
+
+					m_lock.lock();
+				}
+
+				m_rx_current = (m_rx_current + 1) % m_rx_descriptor_count;
+
+				descriptor.command = descriptor.command | RTL8169_DESC_CMD_OWN;
+			}
+
+			SpinLockAsMutex smutex(m_lock, InterruptState::Enabled);
+			m_thread_blocker.block_indefinite(&smutex);
+		}
+
+		m_thread_is_dead = true;
+	}
+
 	void RTL8169::handle_irq()
 	{
 		const uint16_t interrupt_status = m_io_bar_region->read16(RTL8169_IO_ISR);
@@ -251,7 +310,7 @@ namespace Kernel
 			dprintln("link status -> {}", m_link_up.load());
 		}
 
-		if (interrupt_status & RTL8169_IR_TOK)
+		if (interrupt_status & (RTL8169_IR_TOK | RTL8169_IR_ROK))
 		{
 			SpinLockGuard _(m_lock);
 			m_thread_blocker.unblock();
@@ -266,38 +325,6 @@ namespace Kernel
 		if (interrupt_status & RTL8169_IR_FVOW)
 			dwarnln("Rx FIFO overflow");
 		// dont log TDU is sent after each sent packet
-
-		if (!(interrupt_status & RTL8169_IR_ROK))
-			return;
-
-		constexpr size_t buffer_size = 8192;
-
-		for (;;)
-		{
-			auto& descriptor = reinterpret_cast<volatile RTL8169Descriptor*>(m_rx_descriptor_region->vaddr())[m_rx_current];
-			if (descriptor.command & RTL8169_DESC_CMD_OWN)
-				break;
-
-			// packet buffer can only hold single packet, so we should not receive any multi-descriptor packets
-			ASSERT((descriptor.command & RTL8169_DESC_CMD_LS) && (descriptor.command & RTL8169_DESC_CMD_FS));
-
-			const uint16_t packet_length = descriptor.command & 0x3FFF;
-			if (packet_length > buffer_size)
-				dwarnln("Got {} bytes to {} byte buffer", packet_length, buffer_size);
-			else if (descriptor.command & (1u << 21))
-				; // descriptor has an error
-			else
-			{
-				NetworkManager::get().on_receive(*this, BAN::ConstByteSpan {
-					reinterpret_cast<const uint8_t*>(m_rx_buffer_region->vaddr() + m_rx_current * buffer_size),
-					packet_length
-				});
-			}
-
-			m_rx_current = (m_rx_current + 1) % m_rx_descriptor_count;
-
-			descriptor.command = descriptor.command | RTL8169_DESC_CMD_OWN;
-		}
 	}
 
 }

kernel/kernel/Networking/TCPSocket.cpp

@@ -524,24 +524,33 @@ namespace Kernel
 		return result;
 	}
 
-	void TCPSocket::add_protocol_header(BAN::ByteSpan packet, uint16_t dst_port, PseudoHeader pseudo_header)
+	void TCPSocket::get_protocol_header(BAN::ByteSpan header_buffer, BAN::ConstByteSpan payload, uint16_t dst_port, PseudoHeader pseudo_header)
 	{
 		ASSERT(m_next_flags);
 		ASSERT(m_mutex.locker() == Thread::current().tid());
-
+		ASSERT(header_buffer.size() == protocol_header_size());
-		auto& header = packet.as<TCPHeader>();
-		memset(&header, 0, sizeof(TCPHeader));
-		memset(header.options, TCPOption::End, m_tcp_options_bytes);
 
 		m_last_sent_window_size = m_recv_window.buffer->size() - m_recv_window.data_size;
+		if (m_should_send_zero_window)
+			m_last_sent_window_size = 0;
+
+		m_should_send_ack = false;
+		m_should_send_zero_window = false;
+
+		auto& header = header_buffer.as<TCPHeader>();
+		header = {
+			.src_port = bound_port(),
+			.dst_port = dst_port,
+			.seq_number = m_send_window.current_seq + m_send_window.has_ghost_byte,
+			.ack_number = m_recv_window.start_seq + m_recv_window.data_size + m_recv_window.has_ghost_byte,
+			.data_offset = (sizeof(TCPHeader) + m_tcp_options_bytes) / sizeof(uint32_t),
+			.flags = m_next_flags,
+			.window_size = BAN::Math::min<size_t>(0xFFFF, m_last_sent_window_size >> m_recv_window.scale_shift),
+			.checksum = 0,
+			.urgent_pointer = 0,
+		};
+		memset(header.options, 0, m_tcp_options_bytes);
 
-		header.src_port = bound_port();
-		header.dst_port = dst_port;
-		header.seq_number = m_send_window.current_seq + m_send_window.has_ghost_byte;
-		header.ack_number = m_recv_window.start_seq + m_recv_window.data_size + m_recv_window.has_ghost_byte;
-		header.data_offset = (sizeof(TCPHeader) + m_tcp_options_bytes) / sizeof(uint32_t);
-		header.window_size = BAN::Math::min<size_t>(0xFFFF, m_last_sent_window_size >> m_recv_window.scale_shift);
-		header.flags = m_next_flags;
 		if (header.flags & FIN)
 			m_send_window.has_ghost_byte = true;
 		m_next_flags = 0;
@@ -566,10 +575,12 @@ namespace Kernel
 			m_send_window.current_seq = m_send_window.start_seq;
 		}
 
-		pseudo_header.extra = packet.size();
+		const BAN::ConstByteSpan buffers[] {
-		header.checksum = calculate_internet_checksum(packet, pseudo_header);
+			BAN::ConstByteSpan::from(pseudo_header),
-
+			header_buffer,
-		m_should_send_ack = false;
+			payload,
+		};
+		header.checksum = calculate_internet_checksum({ buffers, sizeof(buffers) / sizeof(*buffers) });
 
 		dprintln_if(DEBUG_TCP, "sending {} {8b}", (uint8_t)m_state, header.flags);
 		dprintln_if(DEBUG_TCP, "  ack {}", (uint32_t)header.ack_number);
@@ -603,14 +614,17 @@ namespace Kernel
 				auto interface = interface_or_error.release_value();
 
 				auto& addr_in = *reinterpret_cast<const sockaddr_in*>(sender);
-				checksum = calculate_internet_checksum(buffer,
+				const PseudoHeader pseudo_header {
-					PseudoHeader {
+					.src_ipv4 = BAN::IPv4Address(addr_in.sin_addr.s_addr),
-						.src_ipv4 = BAN::IPv4Address(addr_in.sin_addr.s_addr),
+					.dst_ipv4 = interface->get_ipv4_address(),
-						.dst_ipv4 = interface->get_ipv4_address(),
+					.protocol = NetworkProtocol::TCP,
-						.protocol = NetworkProtocol::TCP,
+					.length = buffer.size(),
-						.extra = buffer.size()
+				};
-					}
+				const BAN::ConstByteSpan buffers[] {
-				);
+					BAN::ConstByteSpan::from(pseudo_header),
+					buffer
+				};
+				checksum = calculate_internet_checksum({ buffers, sizeof(buffers) / sizeof(*buffers) });
 			}
 			else
 			{
@@ -757,9 +771,9 @@ namespace Kernel
 				break;
 		}
 
-		// TODO: even without SACKs, if other end sends seq [0, 1000] and our current seq is 100, we should accept
+		const uint32_t expected_seq = m_recv_window.start_seq + m_recv_window.data_size + m_recv_window.has_ghost_byte;
-		//       packet with seq [100, 1000]
+
-		if (header.seq_number != m_recv_window.start_seq + m_recv_window.data_size + m_recv_window.has_ghost_byte)
+		if (header.seq_number > expected_seq)
 			dprintln_if(DEBUG_TCP, "Missing packets");
 		else if (check_payload)
 		{
@@ -770,7 +784,19 @@ namespace Kernel
 				m_send_window.current_ack = header.ack_number;
 
 			auto payload = buffer.slice(header.data_offset * sizeof(uint32_t));
-			if (payload.size() > 0 && m_recv_window.data_size < m_recv_window.buffer->size())
+
+			if (header.seq_number < expected_seq)
+			{
+				const uint32_t already_received_bytes = expected_seq - header.seq_number;
+				if (already_received_bytes <= payload.size())
+					payload = payload.slice(already_received_bytes);
+				else
+					payload = {};
+			}
+
+			const bool can_receive_new_data = (payload.size() > 0 && m_recv_window.data_size < m_recv_window.buffer->size());
+
+			if (can_receive_new_data)
 			{
 				auto* recv_base = reinterpret_cast<uint8_t*>(m_recv_window.buffer->vaddr());
 
@@ -787,12 +813,12 @@ namespace Kernel
 				epoll_notify(EPOLLIN);
 
 				dprintln_if(DEBUG_TCP, "Received {} bytes", nrecv);
-
-				m_should_send_ack = true;
 			}
 
 			// make sure zero window is reported
-			if (m_next_flags == 0 && m_last_sent_window_size > 0 && m_recv_window.data_size == m_recv_window.buffer->size())
+			if (m_last_sent_window_size > 0 && m_recv_window.data_size == m_recv_window.buffer->size())
+				m_should_send_zero_window = true;
+			else if (can_receive_new_data)
 				m_should_send_ack = true;
 		}
 
@@ -915,7 +941,9 @@ namespace Kernel
 
 			const bool should_retransmit = m_send_window.had_zero_window || (m_send_window.sent_size > 0 && current_ms >= m_send_window.last_send_ms + retransmit_timeout_ms);
 
-			if (m_send_window.sent_size < m_send_window.scaled_size() && (should_retransmit || m_send_window.data_size > m_send_window.sent_size))
+			const bool can_send_new_data = (m_send_window.data_size > m_send_window.sent_size && m_send_window.sent_size < m_send_window.scaled_size());
+
+			if (m_send_window.scaled_size() > 0 && (should_retransmit || can_send_new_data))
 			{
 				m_send_window.had_zero_window = false;
 
@@ -927,7 +955,7 @@ namespace Kernel
 
 				const size_t total_send = BAN::Math::min<size_t>(
 					m_send_window.data_size - send_start_offset,
-					m_send_window.scaled_size() - m_send_window.sent_size
+					m_send_window.scaled_size() - send_start_offset
 				);
 
 				m_send_window.current_seq = m_send_window.start_seq + send_start_offset;
@@ -961,15 +989,18 @@ namespace Kernel
 				continue;
 			}
 
-			if (m_should_send_ack)
+			if (const size_t ack_count = m_should_send_ack + m_should_send_zero_window)
 			{
 				ASSERT(m_connection_info.has_value());
 				auto* target_address = reinterpret_cast<const sockaddr*>(&m_connection_info->address);
 				auto target_address_len = m_connection_info->address_len;
 
-				m_next_flags = ACK;
+				for (size_t i = 0; i < ack_count; i++)
-				if (auto ret = m_network_layer.sendto(*this, {}, target_address, target_address_len); ret.is_error())
+				{
-					dwarnln("{}", ret.error());
+					m_next_flags = ACK;
+					if (auto ret = m_network_layer.sendto(*this, {}, target_address, target_address_len); ret.is_error())
+						dwarnln("{}", ret.error());
+				}
 			}
 
 			m_thread_blocker.unblock();

kernel/kernel/Networking/UDPSocket.cpp

@@ -35,13 +35,26 @@ namespace Kernel
 		m_address_len = 0;
 	}
 
-	void UDPSocket::add_protocol_header(BAN::ByteSpan packet, uint16_t dst_port, PseudoHeader)
+	void UDPSocket::get_protocol_header(BAN::ByteSpan header_buffer, BAN::ConstByteSpan payload, uint16_t dst_port, PseudoHeader pseudo_header)
 	{
-		auto& header = packet.as<UDPHeader>();
+		ASSERT(header_buffer.size() == protocol_header_size());
-		header.src_port = bound_port();
+
-		header.dst_port = dst_port;
+		auto& header = header_buffer.as<UDPHeader>();
-		header.length = packet.size();
+		header = {
-		header.checksum = 0;
+			.src_port = bound_port(),
+			.dst_port = dst_port,
+			.length = protocol_header_size() + payload.size(),
+			.checksum = 0,
+		};
+
+		const BAN::ConstByteSpan buffers[] {
+			BAN::ConstByteSpan::from(pseudo_header),
+			header_buffer,
+			payload,
+		};
+		header.checksum = calculate_internet_checksum({ buffers, sizeof(buffers) / sizeof(*buffers) });
+		if (header.checksum == 0)
+			header.checksum = 0xFFFF;
 	}
 
 	void UDPSocket::receive_packet(BAN::ConstByteSpan packet, const sockaddr* sender, socklen_t sender_len)