work blyattt

build.gradle.kts

@@ -68,6 +68,7 @@ tasks.register("generateTestServerConfig") {
             {
                 "type": "server",
                 "address": "10.1.0.1",
+                "outInterface": "enp9s0",
                 "port": 9093
             }
         """.trimIndent())

src/main/c/tun.c

@@ -1,5 +1,15 @@
 #include <jni.h>
+#include <unistd.h>
 #include <fcntl.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_link.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
 #include <linux/if_tun.h>
 #include <linux/if.h>
 #include <sys/ioctl.h>
@@ -10,6 +20,81 @@
 #include <sys/ioctl.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
+#include <stdlib.h>
+
+JNIEXPORT jint JNICALL
+Java_su_sonoma_TunDevice_addDefaultRoute(
+    JNIEnv *env,
+    jobject obj,
+    jstring ifname
+) {
+
+    struct {
+        struct nlmsghdr nlh;
+        struct rtmsg rtm;
+        char buf[4096];
+    } req;
+
+    memset(&req, 0, sizeof(req));
+
+    const char *c_ifname = (*env)->GetStringUTFChars(env, ifname, 0);
+
+    if (c_ifname == NULL) {
+        return -1;
+    }
+
+    int ifindex = if_nametoindex(c_ifname);
+
+    req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+    req.nlh.nlmsg_type = RTM_NEWROUTE;
+    req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_REPLACE;
+    req.nlh.nlmsg_seq = 1;
+    req.nlh.nlmsg_pid = getpid();
+
+    req.rtm.rtm_family = AF_INET;
+    req.rtm.rtm_table = RT_TABLE_MAIN;
+    req.rtm.rtm_protocol = RTPROT_STATIC;
+    req.rtm.rtm_scope = RT_SCOPE_UNIVERSE;
+    req.rtm.rtm_type = RTN_UNICAST;
+    req.rtm.rtm_dst_len = 0;
+
+    struct rtattr *rta = (struct rtattr *) (((char *) &req) + NLMSG_ALIGN(req.nlh.nlmsg_len));
+    rta->rta_type = RTA_OIF;
+    rta->rta_len = RTA_LENGTH(sizeof(int));
+    *(int *) RTA_DATA(rta) = ifindex;
+
+    req.nlh.nlmsg_len = NLMSG_ALIGN(req.nlh.nlmsg_len) + RTA_LENGTH(sizeof(int));
+
+    int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+    if (sock < 0) {
+        perror("socket");
+        return -1;
+    }
+
+    struct sockaddr_nl addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.nl_family = AF_NETLINK;
+
+    if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        perror("bind");
+        close(sock);
+        return -1;
+    }
+
+    struct sockaddr_nl kernel;
+    memset(&kernel, 0, sizeof(kernel));
+    kernel.nl_family = AF_NETLINK;
+
+    if (sendto(sock, &req, req.nlh.nlmsg_len, 0,
+               (struct sockaddr *)&kernel, sizeof(kernel)) < 0) {
+        perror("sendto");
+        close(sock);
+        return -1;
+    }
+
+    close(sock);
+    return 0;
+}
 
 static int tun_set_up(const char *ifname) {
     struct ifreq ifr;
@@ -99,3 +184,188 @@ Java_su_sonoma_TunDevice_ioctlTun(
 
     return result;
 }
+
+static int add_route(const char *ifname, const char *cidr) {
+
+    struct {
+        struct nlmsghdr nlh;
+        struct rtmsg rtm;
+        char buf[256];
+    } req;
+
+    memset(&req, 0, sizeof(req));
+
+    int ifindex = if_nametoindex(ifname);
+
+    if (ifindex == 0) {
+        perror("if_nametoindex");
+        return -1;
+    }
+
+    char ip[64];
+    int prefix;
+
+    if (sscanf(cidr, "%63[^/]/%d", ip, &prefix) != 2) {
+        fprintf(stderr, "Invalid CIDR\n");
+        return -1;
+    }
+
+    struct in_addr dst;
+
+    if (inet_pton(AF_INET, ip, &dst) != 1) {
+        perror("inet_pton");
+        return -1;
+    }
+
+    req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+    req.nlh.nlmsg_type = RTM_NEWROUTE;
+
+    req.nlh.nlmsg_flags =
+        NLM_F_REQUEST |
+        NLM_F_CREATE |
+        NLM_F_EXCL;
+
+    req.rtm.rtm_family = AF_INET;
+    req.rtm.rtm_table = RT_TABLE_MAIN;
+    req.rtm.rtm_protocol = RTPROT_STATIC;
+    req.rtm.rtm_scope = RT_SCOPE_LINK;
+    req.rtm.rtm_type = RTN_UNICAST;
+
+    req.rtm.rtm_dst_len = prefix;
+
+    struct rtattr *rta;
+
+    rta = (struct rtattr *)
+        (((char *)&req) + NLMSG_ALIGN(req.nlh.nlmsg_len));
+
+    rta->rta_type = RTA_DST;
+    rta->rta_len = RTA_LENGTH(sizeof(dst));
+
+    memcpy(RTA_DATA(rta), &dst, sizeof(dst));
+
+    req.nlh.nlmsg_len =
+        NLMSG_ALIGN(req.nlh.nlmsg_len) +
+        RTA_LENGTH(sizeof(dst));
+
+    rta = (struct rtattr *)
+        (((char *)&req) + NLMSG_ALIGN(req.nlh.nlmsg_len));
+
+    rta->rta_type = RTA_OIF;
+    rta->rta_len = RTA_LENGTH(sizeof(int));
+
+    memcpy(RTA_DATA(rta), &ifindex, sizeof(int));
+
+    req.nlh.nlmsg_len =
+        NLMSG_ALIGN(req.nlh.nlmsg_len) +
+        RTA_LENGTH(sizeof(int));
+
+    int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+
+    if (sock < 0) {
+        perror("socket");
+        return -1;
+    }
+
+    struct sockaddr_nl nladdr;
+    memset(&nladdr, 0, sizeof(nladdr));
+
+    nladdr.nl_family = AF_NETLINK;
+
+    if (sendto(
+            sock,
+            &req,
+            req.nlh.nlmsg_len,
+            0,
+            (struct sockaddr *)&nladdr,
+            sizeof(nladdr)
+        ) < 0) {
+
+        perror("sendto");
+        close(sock);
+        return -1;
+    }
+
+    close(sock);
+
+    return 0;
+}
+
+JNIEXPORT jint JNICALL
+Java_su_sonoma_TunDevice_addRoute(
+    JNIEnv *env,
+    jobject obj,
+    jstring ifname,
+    jstring cidr
+) {
+
+    const char *c_ifname =
+        (*env)->GetStringUTFChars(env, ifname, 0);
+
+    const char *c_cidr =
+        (*env)->GetStringUTFChars(env, cidr, 0);
+
+    if (!c_ifname || !c_cidr) {
+        return -1;
+    }
+
+    int result = add_route(c_ifname, c_cidr);
+
+    (*env)->ReleaseStringUTFChars(env, ifname, c_ifname);
+    (*env)->ReleaseStringUTFChars(env, cidr, c_cidr);
+
+    return result;
+}
+
+JNIEXPORT jint JNICALL
+Java_su_sonoma_TunDevice_enableIpForwarding(
+    JNIEnv *env,
+    jobject obj
+) {
+
+    int fd = open(
+        "/proc/sys/net/ipv4/ip_forward",
+        O_WRONLY
+    );
+
+    if (fd < 0) {
+        return -1;
+    }
+
+    const char *value = "1";
+
+    ssize_t result = write(fd, value, 1);
+
+    close(fd);
+
+    return result == 1 ? 0 : -1;
+}
+
+JNIEXPORT jint JNICALL
+Java_su_sonoma_TunDevice_enableMasquerade(
+    JNIEnv *env,
+    jobject obj,
+    jstring iface
+) {
+
+    const char *c_iface =
+        (*env)->GetStringUTFChars(env, iface, 0);
+
+    if (c_iface == NULL) {
+        return -1;
+    }
+
+    char command[256];
+
+    snprintf(
+        command,
+        sizeof(command),
+        "iptables -t nat -A POSTROUTING -o %s -j MASQUERADE",
+        c_iface
+    );
+
+    int result = system(command);
+
+    (*env)->ReleaseStringUTFChars(env, iface, c_iface);
+
+    return result;
+}

src/main/kotlin/Client.kt

@@ -1,48 +1,75 @@
 package su.sonoma
 
 import kotlinx.coroutines.*
+import java.io.BufferedInputStream
+import java.io.BufferedOutputStream
 import java.io.DataInputStream
 import java.net.Socket
 
-fun startClient(host: String, address: String, port: Int) = runBlocking {
+fun startClient(host: String, address: String, port: Int, tun: String) = runBlocking {
     println("Client started")
-    val tun = TunDevice(address)
+    val tun = TunDevice(address, tun)
+    tun.addDefaultRoute()
 
     println("Client trying to connect - $host:$port")
     val socket = Socket(host, port)
+    println("Client trying connected - $host:$port")
 
-    val input = socket.getInputStream()
-    val output = socket.getOutputStream()
-
-    println("Client trying to pair")
-
-    launch {
-        val buffer = ByteArray(32768)
-        println("Client connected - $host:$port")
-
-        while (true) {
-            val len = tun.input.read(buffer)
-
-            if (len > 0) {
-                output.write(len shr 8)
-                output.write(len)
-
-                output.write(buffer, 0, len)
-            }
+    launch(Dispatchers.IO) {
+        try {
+            handleClient(socket, tun)
+        } catch (e: Exception) {
+            e.printStackTrace()
         }
     }
 
-    launch {
-        val buffer = ByteArray(32768)
-
-        while (true) {
-            val hi = input.read()
-            val lo = input.read()
-            val len = (hi shl 8) or lo
-
-            DataInputStream(input).readFully(buffer, 0, len)
-
-            tun.output.write(buffer, 0, len)
+    launch(Dispatchers.IO) {
+        try {
+            forwardClient(socket, tun)
+        } catch (e: Exception) {
+            e.printStackTrace()
         }
     }
 }
+
+fun forwardClient(socket: Socket, tun: TunDevice) {
+    val buffer = ByteArray(1500)
+    val input = BufferedInputStream(socket.getInputStream())
+
+    while (true) {
+
+        val hi = input.read()
+        if (hi == -1) break
+
+        val lo = input.read()
+        if (lo == -1) break
+
+        val len = (hi shl 8) or lo
+        //println("Message length: $len")
+
+        var read = 0
+        while (read < len) {
+            val r = input.read(buffer, read, len - read)
+            if (r == -1) break
+            read += r
+        }
+
+        tun.output.write(buffer, 0, read)
+        tun.output.flush()
+    }
+}
+
+fun handleClient(socket: Socket, tun: TunDevice) {
+    val output = BufferedOutputStream(socket.getOutputStream())
+    val buffer = ByteArray(1500)
+
+    while (true) {
+        val len = tun.input.read(buffer)
+        if (len <= 0) continue
+
+        output.write((len shr 8) and 0xFF)
+        output.write(len and 0xFF)
+        output.write(buffer, 0, len)
+        output.flush()
+    }
+}

src/main/kotlin/Config.kt

@@ -8,6 +8,8 @@ import java.io.File
 data class Config(
     val type: String,
     val host: String? = null,
+    val tun: String = "awake0",
+    val outInterface: String = "eth0",
     val address: String,
     val port: Int,
 )

src/main/kotlin/Main.kt

@@ -7,8 +7,8 @@ fun main(args: Array<String>) {
     val config = loadConfig(File(configArg))
 
     when (config.type) {
-        "server" -> startServer(config.address, config.port)
-        "client" -> startClient(config.host ?: error("Invalid config"), config.address, config.port)
+        "server" -> startServer(config.address, config.port, config.tun, config.outInterface)
+        "client" -> startClient(config.host ?: error("Invalid config"), config.address, config.port, config.tun)
         else -> {
             error("Invalid type")
         }

src/main/kotlin/Server.kt

@@ -1,12 +1,17 @@
 package su.sonoma
 
 import kotlinx.coroutines.*
+import java.io.BufferedInputStream
+import java.io.BufferedOutputStream
 import java.net.ServerSocket
 import java.net.Socket
 import java.io.DataInputStream
 
-fun startServer(address: String, port: Int) = runBlocking {
-    val tun = TunDevice(address)
+fun startServer(address: String, port: Int, tun: String, outIntefrace: String) = runBlocking {
+    val tun = TunDevice(address, "awake0")
+    tun.addRoute()
+    tun.enableIpForwarding()
+    tun.enableMasquerade(outIntefrace)
 
     val server = ServerSocket(port)
     println("Server started on $port")
@@ -21,55 +26,80 @@ fun startServer(address: String, port: Int) = runBlocking {
             try {
                 handle(client, tun)
             } catch (e: Exception) {
-                println("${client.inetAddress} Client disconnected: ${e.message}")
+                e.printStackTrace()
+            }
+        }
+
+        launch(Dispatchers.IO) {
+            try {
+                forward(client, tun)
+            } catch (e: Exception) {
+                e.printStackTrace()
             }
         }
     }
 }
 
-suspend fun handle(socket: Socket, tun: TunDevice) {
-    val input = withContext(Dispatchers.IO) {
-        socket.getInputStream()
-    }
-    val output = withContext(Dispatchers.IO) {
-        socket.getOutputStream()
-    }
+fun handle(socket: Socket, tun: TunDevice) {
 
-    val buffer = ByteArray(32768)
+    val input = BufferedInputStream(socket.getInputStream())
+
+    val buffer = ByteArray(1500)
 
-    withContext(Dispatchers.IO) {
     while (true) {
 
         val hi = input.read()
-
         val lo = input.read()
 
+        if (hi == -1 || lo == -1) {
+            println("${socket.inetAddress} Client disconnected")
+            break
+        }
+
         val len = (hi shl 8) or lo
 
-            DataInputStream(input).readFully(buffer, 0, len)
+        //println("Message length: $len")
 
-            val packet = buffer.copyOf(len)
+        if (len <= 0 || len > buffer.size) {
+            println("Invalid packet size: $len")
+            break
+        }
 
-            val response = forwardPacket(packet)
+        var offset = 0
+        while (offset < len) {
+            val r = input.read(buffer, offset, len - offset)
 
-            //output.write(response.size shr 8)
-            //output.write(response.size)
-            //output.write(response)
-            tun.output.write(packet, 0, len)
+            //println("Read $r from client")
+
+            if (r == -1) {
+                println("${socket.inetAddress} Client closed stream")
+                return
+            }
+            offset += r
+        }
+
+        runCatching {
+            tun.output.write(buffer, 0, len)
+            tun.output.flush()
+        }
+        //println("Write in tun")
+    }
+}
+
+fun forward(socket: Socket, tun: TunDevice) {
+
+    val readBuffer = ByteArray(1500)
+    val output = BufferedOutputStream(socket.getOutputStream())
+
+    while (true) {
+        val responseLen = tun.input.read(readBuffer)
+        if (responseLen > 0) {
+
+            output.write((responseLen shr 8) and 0xFF)
+            output.write(responseLen and 0xFF)
+
+            output.write(readBuffer, 0, responseLen)
+            output.flush()
         }
     }
 }
-fun forwardPacket(packet: ByteArray): ByteArray {
-    val host = "localhost"
-    val port = 1080
-
-    val socket = Socket(host, port)
-
-    socket.getOutputStream().write(packet)
-
-    val response = socket.getInputStream().readBytes()
-
-    socket.close()
-
-    return response
-}

src/main/kotlin/TunDevice.kt

@@ -5,11 +5,13 @@ import java.io.FileDescriptor
 import java.io.FileInputStream
 import java.io.FileOutputStream
 import java.io.RandomAccessFile
+import java.nio.channels.DatagramChannel
+import java.nio.channels.FileChannel
 
 class TunDevice(
-    private val ip: String
+    private val ip: String,
+    private val name: String
 ) {
-    val name: String = "tun0"
 
     companion object {
         init {
@@ -46,4 +48,30 @@ class TunDevice(
         ip: String,
         flags: Int
     ): Int
+
+    private external fun addDefaultRoute(
+        name: String,
+    ): Int
+
+    fun addDefaultRoute() {
+        addDefaultRoute(name)
+    }
+
+    private external fun addRoute(ifName: String, cidr: String): Int
+
+    fun addRoute() {
+        addRoute(name, toCidr24(ip))
+    }
+
+    fun toCidr24(ip: String): String {
+        val parts = ip.split(".")
+
+        require(parts.size == 4)
+
+        return "${parts[0]}.${parts[1]}.${parts[2]}.0/24"
+    }
+
+    external fun enableIpForwarding(): Int
+
+    external fun enableMasquerade(iface: String): Int
 }