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https://gitee.com/willfree/min-vpn-client_v2.git
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更换目的地址、tcp端口，计算ip包、tcp报文字段中的校验和，并写回tun网卡中。下一步研究tun网卡的流量流向，以及如何、从何读出地址修改后的ip包。
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liubohahaha committed
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commit
de51fdec72
1 file changed
+173
-25
+173
-25
@@ -27,6 +27,7 @@ import java.util.Arrays;
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import java.util.Set;
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import common.LoggerHelper;
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import jnr.ffi.annotations.In;
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import util.ByteHelper;
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public class MINVpnLBConnection implements MINVpnConnection {
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@@ -111,6 +112,7 @@ public class MINVpnLBConnection implements MINVpnConnection {
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builder.setMtu(8000);
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builder.addAddress(allocatedAddress,24);
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builder.addRoute("10.255.0.3",32);
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builder.addRoute("192.168.0.0",16);
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builder.addDnsServer("114.114.114.114");
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// 1.2创建一个接口
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final ParcelFileDescriptor vpnInterface;
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@@ -169,15 +171,67 @@ public class MINVpnLBConnection implements MINVpnConnection {
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}
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int[] ip_address_unsignedInt_first=new int[8];
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if(readLen>0){
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System.out.println("A new packet，");
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System.out.println("read from tun , readLen ="+readLen);
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ip_packet_read_from_tun.position(0);
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ip_packet_read_from_tun.limit(readLen);
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try {
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//System.out.println("after changing, position is"+ip_NAT_packet.position());
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System.out.println("直接写入，再读出");
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//outputStream.write(ip_NAT_packet.array(), 0, ip_NAT_packet.position());
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outputStream.write(ip_packet_read_from_tun.array(), 0, ip_packet_read_from_tun.position());
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ByteBuffer temp_buffer = ByteBuffer.allocate(MAX_PACKET_SIZE);
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int temp_readLen=inputStream.read(temp_buffer.array(), 0, MAX_PACKET_SIZE);
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System.out.println("temp readLen is "+temp_readLen);
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byte[] tempData = new byte[temp_readLen];
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System.arraycopy(temp_buffer.array(), 0, tempData, 0, temp_readLen);
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printHexString("直接从TUN中读：",tempData);
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} catch (IOException e) {
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e.printStackTrace();
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System.out.println("将抓转换后的地址写入tun网卡失败");
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}
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// String binaryString = Integer.toBinaryString(first);
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byte[] ipPackageData = new byte[readLen];
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System.arraycopy(ip_packet_read_from_tun.array(), 0, ipPackageData, 0, readLen);
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System.out.println("ip packet's content is: " + Arrays.toString(ipPackageData));
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// System.out.println("ip packet's content is: " + Arrays.toString(ipPackageData));
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if(ipPackageData[12]==0 && ipPackageData[13]==0
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&& ipPackageData[14]==0 && ipPackageData[15]==0){
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System.out.println("源地址为0.0.0.0，暂时跳过");
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continue;
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}
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System.out.println("A new packet，");
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System.out.println("read from tun , readLen ="+readLen);
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printHexString("ip packet's content is: ",ipPackageData);
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//ip包的各种信息
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//ip头部长度，tcp报文长度
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int ip_head_length=(ipPackageData[0] & 0x0F)*4;
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int tcp_length=readLen-ip_head_length;
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//源端口、目的端口
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byte[] source_port=new byte[2];
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source_port[0]=ipPackageData[ip_head_length];
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source_port[1]=ipPackageData[ip_head_length+1];
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byte[] destination_port=new byte[2];
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destination_port[0]=ipPackageData[ip_head_length+2];
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destination_port[1]=ipPackageData[ip_head_length+3];
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byte[] test_ipPackageData = new byte[readLen];
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System.arraycopy(ip_packet_read_from_tun.array(), 0, test_ipPackageData, 0, readLen);
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ByteBuffer test_ip_packet=ByteBuffer.allocate(MAX_PACKET_SIZE);
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test_ip_packet.put(test_ipPackageData);
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//calculate the head checksum
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// short ip_checksum=computeChecksum(ipPackageData,20);
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// System.out.println("the checksum of ip packet is "+ Integer.toHexString(Short.toUnsignedInt(ip_checksum)));
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// System.out.println("the checksum(unsigned int) of ip packet is "+ Short.toUnsignedInt(ip_checksum));
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// System.out.println("the checksum(short) of ip packet is "+ ip_checksum);
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// 将byte数组按16进制输出
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// byte[] test=new byte[2];
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// test=ByteHelper.uint16ToByteArray(Short.toUnsignedInt(ip_checksum));
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// System.out.println("the checksum(hex) of ip packet is "+Integer.toHexString(test[0] & 0xFF)+" "+Integer.toHexString(test[1] & 0xFF));
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//读取源ip: [0]-[3],10.254.0.2 , 目的ip: [4]-[7],10.255.0.3
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for(int i=12;i<20;i++){
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@@ -188,12 +242,14 @@ public class MINVpnLBConnection implements MINVpnConnection {
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System.out.print("source ip is "+ip_address_unsignedInt_first[i]);
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else if(i>=1&&i<=3)
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System.out.print("."+ip_address_unsignedInt_first[i]);
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else if(i==4)
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else if(i==4){
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System.out.print(" source tcp port is "+ByteHelper.new_byteArrayToInt(source_port));
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System.out.print("\ndestination ip is "+ip_address_unsignedInt_first[i]);
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}
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else
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System.out.print("."+ip_address_unsignedInt_first[i]);
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}
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System.out.print("\n");
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System.out.print(" destination tcp port is "+ByteHelper.new_byteArrayToInt(destination_port)+"\n");
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// 跳转到第3步
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//第3.2步，如果目的地址是10.254.0.1，用face发出去【不用实现，打印即可】
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@@ -206,22 +262,66 @@ public class MINVpnLBConnection implements MINVpnConnection {
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else{
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System.out.println("目的地址不是10.254.0.1，进行地址转换");
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ip_NAT_packet.clear();
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ip_NAT_packet.position(0);
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//更换ip包中目的地址为要转换的地址
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byte[] address_to_NAT_byte=new byte[4];
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int[] address_to_NAT_unsignedINT={192,168,3,2};
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int[] address_to_NAT_unsignedINT={192,168,3,12};
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for(int i=0;i<4;i++){
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address_to_NAT_byte[i]=ByteHelper.uint8ToByte(address_to_NAT_unsignedINT[i]);
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//System.out.print(address_to_NAT_byte[i]+" ");
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ipPackageData[i+16]=address_to_NAT_byte[i];
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}
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//calculate the checksum of ip packet, replace the checksum
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short ip_checksum=computeChecksum(ipPackageData,ip_head_length,10);
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byte[] new_ip_checksum;
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new_ip_checksum=ByteHelper.uint16ToByteArray(Short.toUnsignedInt(ip_checksum));
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ipPackageData[10]=new_ip_checksum[0];
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ipPackageData[11]=new_ip_checksum[1];
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//calculate the checksum of tcp,replace the checksum
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System.out.println("is tcp:"+Byte.toUnsignedInt(ipPackageData[9]));
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if(Byte.toUnsignedInt(ipPackageData[9])==6){
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byte[] temp_head_to_calculate_checksum;
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if((tcp_length+12)%2==0)
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temp_head_to_calculate_checksum=new byte[tcp_length+12];
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else
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temp_head_to_calculate_checksum=new byte[tcp_length+13];
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//构造tcp伪头部
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for(int i=0;i<8;i++)
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temp_head_to_calculate_checksum[i]=ipPackageData[i+12];
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temp_head_to_calculate_checksum[8]=ByteHelper.uint8ToByte(0);
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temp_head_to_calculate_checksum[9]=ipPackageData[9];
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temp_head_to_calculate_checksum[10]=ByteHelper.uint16ToByteArray(tcp_length)[0];
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temp_head_to_calculate_checksum[11]=ByteHelper.uint16ToByteArray(tcp_length)[1];
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for(int i=0;i<tcp_length;i++){
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temp_head_to_calculate_checksum[i+12]=ipPackageData[ip_head_length+i];
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}
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if((tcp_length+12)%2!=0)
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temp_head_to_calculate_checksum[tcp_length+12]=ByteHelper.uint8ToByte(0);
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//printHexString("content of integrity tcp: ",temp_head_to_calculate_checksum);
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short tcp_checksum=computeChecksum(temp_head_to_calculate_checksum,tcp_length+12,28);
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//System.out.println("the checksum of tcp datagram is "+ Integer.toHexString(Short.toUnsignedInt(tcp_checksum)));
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byte[] new_tcp_checksum;
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new_tcp_checksum=ByteHelper.uint16ToByteArray(Short.toUnsignedInt(tcp_checksum));
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ipPackageData[ip_head_length+16]=new_tcp_checksum[0];
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ipPackageData[ip_head_length+17]=new_tcp_checksum[1];
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}
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System.out.println("before changing, position is"+ip_NAT_packet.position());
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//搜一下怎么换ip地址，还要更换包里面其他的内容吗
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ip_NAT_packet.put(ipPackageData);
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//从buffer中读取转换后的ip包
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// //从buffer中读取转换后的ip包
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// byte[] ipdata_changing= ip_NAT_packet.array();
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// System.out.println("the content of ip packet after changing is: " + Arrays.toString(ipdata_changing));
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// //读取源ip: [12]-[15] , 目的ip: [16]-[19],192.168.3.2
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// printHexString("the content of ip packet after changing is: ",ipdata_changing);
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// //读取源ip: [12]-[15] , 目的ip: [16]-[19],192.168.3.12
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// int[] ip_address_unsignedInt_changing=new int[8];
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// //将ip转化为unsigned int
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// for(int i=12;i<20;i++){
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@@ -238,13 +338,8 @@ public class MINVpnLBConnection implements MINVpnConnection {
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// System.out.print("."+ip_address_unsignedInt_changing[i]);
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// }
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// System.out.print("\n");
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// System.out.println("after changing, position is "+ip_NAT_packet.position());
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try {
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outputStream.write(ip_NAT_packet.array(), 0, ip_NAT_packet.position());
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} catch (IOException e) {
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e.printStackTrace();
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System.out.println("将抓转换后的地址写入tun网卡失败");
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}
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}
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@@ -254,9 +349,19 @@ public class MINVpnLBConnection implements MINVpnConnection {
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readFromTun.start();
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// // 第3.1步，如果目的地址不是10.254.0.1，先将IP包的源端口号和目的IP端口号存入表iptables，
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// // 然后做NAT转换，做完NAT转换的IP包写入tun（通过ParcelFileDescriptor） write()
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// Thread writeToTun = new Thread(() -> {
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// while (!this.stop){
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// //System.out.println("ip_NAT_packet position"+ip_NAT_packet.position());
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//
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// if()
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//
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//
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// ip_NAT_packet.position(0);
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// }
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// });
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// writeToTun.start();
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// 第3.1步，如果目的地址不是10.254.0.1，先将IP包的源端口号和目的IP端口号存入表iptables，
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// 然后做NAT转换，做完NAT转换的IP包写入tun（通过ParcelFileDescriptor） write()
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// Thread writeToTun = new Thread(() -> {
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// while(this.stop){
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// System.out.println("write thread "+temp_buff.position());
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@@ -310,13 +415,56 @@ public class MINVpnLBConnection implements MINVpnConnection {
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return MINVpnLBConnection.class.getSimpleName() + "[" + mConnectionId + "]";
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}
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private void transfer_ip_packet_from_thread(ByteBuffer ip_packet,int readLen){
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temp_buff.clear();
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byte[] ipPackageData = new byte[readLen];
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System.arraycopy(ip_packet.array(), 0, ipPackageData, 0, readLen);
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temp_buff.put(ipPackageData);
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length_of_ip_packet=readLen;
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/**
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* 将byte数组以16进制的形式输出
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*
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* @param b
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* byte[]
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* @return void
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*/
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public static void printHexString(String hint, byte[] b)
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{
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System.out.print(hint);
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for (int i = 0; i < b.length; i++)
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{
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String hex = Integer.toHexString(b[i] & 0xFF);
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if (hex.length() == 1)
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{
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hex = '0' + hex;
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}
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System.out.print(hex.toUpperCase() + " ");
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}
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System.out.println("");
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}
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/**
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* Computes the IPv4 head checksum on the passed stream of bytes
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* representing the packet.
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*
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* @param data
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* The byte stream
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* @param length
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* The length of the IPv4 packet's head
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* @return The computed checksum
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*/
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short computeChecksum(byte[] data,int length,int checksumStart) {
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short checkSum;
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int sum = 0;
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int wordData;
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for (int i = 0; i <= length - 1; i = i + 2) {
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// Skip, if the current bytes are checkSum bytes
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if (i == checksumStart) {
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continue;
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}
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wordData = (data[i] << 8 & 0xFF00) + (data[i + 1] & 0xFF);
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sum = sum + wordData;
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}
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int carry = sum >> 16 & 0xFF;
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int finalSum = (sum & 0xFFFF) + carry;
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checkSum = (short) ~((short) finalSum & 0xFFFF);
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return checkSum;
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}
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}
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