Some Changes/Fixes & Added README.md

README.md

@@ -0,0 +1,37 @@
+# TunMode Android
+
+TunMode is an Android project that routes traffic through a VPN to intercept packets. It supports TCP and UDP protocols and works on a semi-TCP stack, making it suitable for intercepting packets. You can also optionally intercept DNS queries or let the system resolve them. Essentially, TunMode acts as a proxy without editing or blocking any packets, allowing traffic to flow in and out seamlessly.
+
+## Features
+
+- Route traffic through a VPN to intercept packets
+- Support for TCP and UDP protocols
+- Optional DNS query interception
+- Proxy-like functionality with transparent traffic flow
+
+## Notes
+* Might not work properly on Android 14 because of some API changes on that version. I am unable to test it.
+* Doesn't support IPv6.
+
+## Usage
+
+1. [Download the TunMode APK](https://github.com/gxosty/TunMode/releases/latest)
+2. Install the APK on your Android device
+3. Open and click button in the center
+4. Start intercepting packets and DNS queries as needed
+
+### Prerequisites
+
+- Android Studio
+- Android SDK API Level 21 or higher
+- Android NDK 25+ (maybe 24 is also ok, didn't test)
+
+### Building the Project
+
+1. Clone the repository
+2. Open the project in Android Studio
+3. Build and run the project on a connected Android device or emulator
+
+## Contributing
+
+We welcome contributions to TunMode! If you have any ideas, bug fixes, or feature enhancements, feel free to contribute by submitting a pull request. Please refer to the [contribution guidelines](CONTRIBUTING.md) for more information.

app/src/main/cpp/CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.5)
 
-set(CMAKE_BUILD_TYPE Debug)
+set(CMAKE_BUILD_TYPE Release)
 
 if ((CMAKE_BUILD_TYPE STREQUAL "Release") OR (CMAKE_BUILD_TYPE STREQUAL "MinSizeRel"))
 	add_definitions(-DRELEASE_MODE=1)
@@ -14,35 +14,14 @@ include_directories(${CMAKE_SOURCE_DIR}/include)
 include_directories(${CMAKE_SOURCE_DIR}/src/internal)
 
 if (${ANDROID_ABI} STREQUAL "armeabi-v7a")
-	set(DPIMASK_LIBS_DIR "${CMAKE_SOURCE_DIR}/lib/armeabi-v7a")
+	set(TUNMODE_LIBS "${CMAKE_SOURCE_DIR}/lib/armeabi-v7a")
 elseif (${ANDROID_ABI} STREQUAL "arm64-v8a")
-	set(DPIMASK_LIBS_DIR "${CMAKE_SOURCE_DIR}/lib/arm64-v8a")
+	set(TUNMODE_LIBS "${CMAKE_SOURCE_DIR}/lib/arm64-v8a")
 else()
 	message(SEND_ERROR "Wrong ANDROID_ABI: ${ANDROID_ABI}")
 endif()
 
-link_directories(${DPIMASK_LIBS_DIR})
-
-# add_library(crypto SHARED IMPORTED)
-# set_target_properties(
-# 	crypto
-# 	PROPERTIES IMPORTED_LOCATION
-# 	${DPIMASK_LIBS_DIR}/libcrypto.so
-# )
-
-# add_library(ssl SHARED IMPORTED)
-# set_target_properties(
-# 	ssl
-# 	PROPERTIES IMPORTED_LOCATION
-# 	${DPIMASK_LIBS_DIR}/libssl.so
-# )
-
-# add_library(curl SHARED IMPORTED)
-# set_target_properties(
-# 	curl
-# 	PROPERTIES IMPORTED_LOCATION
-# 	${DPIMASK_LIBS_DIR}/libcurl.so
-# )
+link_directories(${TUNMODE_LIBS})
 
 add_library(tunmode SHARED
 	main.cxx
@@ -74,5 +53,4 @@ add_library(tunmode SHARED
 target_link_libraries(tunmode
 	log
 	android
-	z
 )

app/src/main/cpp/include/tunmode/common/buffer.hpp

@@ -16,7 +16,7 @@ namespace tunmode
 		void operator()(const void* buffer, const size_t& size);
 
 	private:
-		char _buffer[TUNMODE_BUFFER_SIZE + 200];
+		char _buffer[TUNMODE_BUFFER_SIZE + 100];
 
 		void _copy(const void* buffer, const size_t& size);
 	};

app/src/main/cpp/include/tunmode/definitions.hpp

@@ -1,7 +1,7 @@
 #pragma once
 
-#define TUNMODE_PACKET_SIZE 8192
-#define TUNMODE_BUFFER_SIZE 8192
+#define TUNMODE_PACKET_SIZE 1500
+#define TUNMODE_BUFFER_SIZE 1500
 
 #define TUNMODE_PROTOCOL_TCP 6
 #define TUNMODE_PROTOCOL_UDP 17

app/src/main/cpp/include/tunmode/manager/udpmanager.hpp

@@ -15,7 +15,7 @@ namespace tunmode
 		void handle_packet(const Packet& packet) override;
 
 	private:
-		Session* add(uintptr_t id) override;
+		Session* add(uint64_t id) override;
 
 		friend class UDPSession;
 	};

app/src/main/cpp/include/tunmode/socket/tcpsocket.hpp

@@ -52,6 +52,7 @@ namespace tunmode
 		int connect(Socket* skt);
 
 		size_t send_tun(Packet& packet) override;
+		size_t send(const Packet& packet) override;
 		size_t send(const Buffer& buffer) override;
 		size_t recv(Buffer& buffer) override;
 
@@ -68,6 +69,8 @@ namespace tunmode
 		in_addr server_addr;
 		u_short server_port;
 
+		bool syn_recved;
+
 		TCPVars vars;
 		TCPState state;
 

app/src/main/cpp/main.cxx

@@ -18,7 +18,6 @@ Java_git_gxosty_tunmode_interceptor_services_TunModeService_tunnelOpenNative(JNI
 	tunmode::params::dns_address.s_addr = 0;
 
 	const char* str_net_iface = env->GetStringUTFChars(net_iface, NULL);
-	const char* str_dns_address = env->GetStringUTFChars(dns_address, NULL);
 
 	struct ifreq ifr;
 	int if_fd = socket(AF_INET, SOCK_DGRAM, 0);
@@ -30,10 +29,14 @@ Java_git_gxosty_tunmode_interceptor_services_TunModeService_tunnelOpenNative(JNI
 	close(if_fd);
 	tunmode::params::net_iface = ((struct sockaddr_in*)&ifr.ifr_addr)->sin_addr;
 
-	inet_pton(AF_INET, str_dns_address, &tunmode::params::dns_address);
-
 	env->ReleaseStringUTFChars(net_iface, str_net_iface);
-	env->ReleaseStringUTFChars(dns_address, str_dns_address);
+
+	if (dns_address)
+	{
+		const char* str_dns_address = env->GetStringUTFChars(dns_address, NULL);
+		inet_pton(AF_INET, str_dns_address, &tunmode::params::dns_address);
+		env->ReleaseStringUTFChars(dns_address, str_dns_address);
+	}
 
 	tunmode::open_tunnel();
 }

app/src/main/cpp/src/tunmode/socket/sessionsocket.cxx

@@ -3,8 +3,11 @@
 #include <tunmode/definitions.hpp>
 
 #include <unistd.h>
+#include <fcntl.h>
 #include <netinet/ip.h>
 
+#include <misc/logger.hpp>
+
 namespace tunmode
 {
 	TunSocket* SessionSocket::tun = nullptr;
@@ -15,6 +18,7 @@ namespace tunmode
 		this->session_pipe[1] = 0;
 
 		pipe2(this->session_pipe, O_DIRECT);
+		// auto res = fcntl(this->session_pipe[1], F_SETPIPE_SZ, 16384);
 	}
 
 	SessionSocket::~SessionSocket()

app/src/main/cpp/src/tunmode/socket/socket.cxx

@@ -5,20 +5,25 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+#include <misc/logger.hpp>
+
 namespace tunmode
 {
 	Socket::Socket(int domain, int type, int protocol) : closed{false}
 	{
+		LOGD_("Socket::Socket()");
 		this->socket = ::socket(domain, type, protocol);
 	}
 
 	Socket::Socket(int socket) : closed{false}
 	{
+		LOGD_("Socket::Socket()");
 		this->socket = socket;
 	}
 
 	Socket::~Socket()
 	{
+		LOGD_("Socket::~Socket()");
 		if (!this->closed)
 			::close(this->socket);
 	}

app/src/main/cpp/src/tunmode/socket/tcpsocket.cxx

@@ -13,11 +13,14 @@
 #include <cstdlib>
 #include <random>
 
+#include <misc/logger.hpp>
+
 namespace tunmode
 {
 	TCPSocket::TCPSocket() : SessionSocket()
 	{
 		this->state = TCPSTATE_LISTEN;
+		this->syn_recved = false;
 	}
 
 	TCPSocket::~TCPSocket()
@@ -27,16 +30,14 @@ namespace tunmode
 
 	int TCPSocket::connect(Socket* skt)
 	{
-		static constexpr char hs_opts[] = {2, 4, 31, 216, 1, 3, 3, 8, 1, 1, 4, 2};
+		static constexpr char hs_opts[] = {2, 4, 5, 180, 1, 3, 3, 8, 1, 1, 4, 2};
 
 		Packet client_packet;
 		client_packet.set_protocol(TUNMODE_PROTOCOL_TCP);
 		Packet server_packet;
 		server_packet.set_protocol(TUNMODE_PROTOCOL_TCP);
 
-		LOGD_("Getting SYN...");
 		*this > client_packet;
-		LOGD_("Got packet");
 
 		ip* ip_header;
 		tcphdr* tcp_header;
@@ -116,6 +117,24 @@ namespace tunmode
 		return SessionSocket::send_tun(packet);
 	}
 
+	size_t TCPSocket::send(const Packet& packet)
+	{
+		ip* ip_header;
+		tcphdr* tcp_header;
+		utils::point_headers_tcp((Packet*)&packet, &ip_header, &tcp_header);
+
+		if (tcp_header->th_flags == TH_SYN)
+		{
+			if (this->syn_recved)
+			{
+				return packet.get_size();
+			}
+			this->syn_recved = true;
+		}
+
+		return SessionSocket::send(packet);
+	}
+
 	size_t TCPSocket::send(const Buffer& buffer)
 	{
 		Packet packet;
@@ -188,13 +207,10 @@ namespace tunmode
 					}
 
 					buffer(in_buffer.get_buffer(), in_buffer.get_size());
-					LOGD_("Buffer size: %lu", buffer.get_size());
-					LOGD_("SEQ: %u", ntohl(tcp_header->th_seq));
 					this->vars.rcv.nxt += in_buffer.get_size();
 
 					if (tcp_header->th_flags != TH_ACK)
 					{
-						LOGD_("PSH -> Sending ACK");
 						Packet client_packet;
 						client_packet.set_protocol(TUNMODE_PROTOCOL_TCP);
 						ip* ip_header2;
@@ -229,7 +245,6 @@ namespace tunmode
 				}
 				else if (tcp_header->th_flags & TH_FIN)
 				{
-					LOGD_("FIN -> Sending ACK");
 					Packet client_packet;
 					client_packet.set_protocol(TUNMODE_PROTOCOL_TCP);
 					ip* ip_header2;
@@ -258,6 +273,7 @@ namespace tunmode
 				}
 				else
 				{
+					utils::print_packet_tcp(&packet);
 					this->reset(packet);
 					buffer.set_size(0);
 					return -1;

app/src/main/java/git/gxosty/tunmode/interceptor/services/TunModeService.java

@@ -42,13 +42,14 @@ public class TunModeService extends VpnService {
 	 *
 	 * Set dns resolver address (e.g. Google Public DNS 8.8.8.8)
 	 *
-	 * You may also set local imaginary fake IP address (e.g. 10.0.0.2)
-	 * to route dns queries over TUN socket. Note that you will handle
-	 * query packets yourself!
+	 * You may also set fake IP address (e.g. 10.0.0.2)
+	 * to route dns queries over TUN socket. Note that you
+	 * will need to identify and handle query packets yourself!
 	 *
 	 * Set to `null` if you want to use system dns resolver
 	 **/
-	public static final String dnsAddress = "8.8.8.8";
+	// public static final String dnsAddress = "8.8.8.8";
+	public static final String dnsAddress = null;
 
 	public static final String INTENT_EXTRA_OPERATION = "TunModeService_Operation";
 	public static final String NOTIFICATION_CHANNEL = "tun_mode_vpn_service_nc";
@@ -196,7 +197,7 @@ private void connect() {
 			VpnService.Builder builder = new VpnService.Builder()
 				.addAddress(TunModeService.tunAddress, 32)
 				.addRoute("0.0.0.0", 0)
-				.setMtu(8192);
+				.setMtu(1500);
 
 			if (TunModeService.dnsAddress != null) {
 				// route dns queries as well