LCX端口转发源码分析
lcx.exe算是端口转发工具中普及率特别高的吧。当然，最近也出了好些Web端口转发工具，这个待后续再分析一下。我从网上下载了一个lcx的源码片段，结合源码谈谈自己的认识。
lcx工作原理是使不同端口之间形成一个回路，这样就可以进行端口转发。常用于外网连接内网3389端口。具体使用方法网上一堆。
这个程序主要采用Socket来实现，有几个比较重要的函数：bind2bind、bind2conn、conn2conn及transmitdata。transmitdata函数是核心，这个函数作用是使得不同端口之间的数据形成一个回路。
注意源代码中的setsocket函数，其中设置了SO_REUSEADDR。设置SO_REUSEADDR之后，可以应用的一种场景就是同一个端口可以绑定多个socket。查看相关资料可以得知，其实设置SO_REUSEADDR之后，还有其他几种应用场景。我试了一下，你把setsocket函数注释掉，在运行这个端口转发程序时，本地listen的时候设置的两个端口不一样程序还是可以正常运行的。启用setsocket函数之后，本地listen的时候，可以设置两个端口为同一个值，但是这样设置的时候，我在虚拟机中无法远程连接，一直就是尝试连接也不报错。原因不因，未深入分析。
网上很多的源码其实是有问题的，下面我分享一个稍作修改的源代码，能够在windows xp +vc6.0下编译通过，理论上是可以在windows系列所有32位版本下运行的。对于64位系统，我也修改了一个版本，在windows 7 x64+vs2013编译通过，主要用于64位windows下运行。可执行文件我就不放出来了，自己编译运行差不多就OK了。
Windows XP +VC6.0下编译通过的源码：
/*************************************************************************************** HTran.cpp - HUC Packet Transmit Tool.** Copyright (C) 2000-2004 HUC All Rights Reserved.** Author : lion* : lion#cnhonker.net* : <a href="http://www.cnhonker.com" target="_blank">http://www.cnhonker.com</a>* :* Notice : Thx to bkbll (bkbll#cnhonker.net)* :* Date : 2003-10-20* :* Complie : cl HTran.cpp* :* Usage : E:\>HTran* : ======================== HUC Packet Transmit Tool V1.00 =======================* : =========== Code by lion & bkbll, Welcome to <a href="http://www.cnhonker.com" target="_blank">http://www.cnhonker.com</a> ==========* :* : [Usage of Packet Transmit:]* : HTran - [-log logfile]* :* : [option:]* : -listen* : -tran* : -slave**************************************************************************************/#include <stdio.h>#include <stdlib.h>#include <winsock2.h>#include <signal.h>#include <errno.h>#include <io.h>#pragma comment(lib, "ws2_32.lib")#define VERSION "1.00"#define TIMEOUT 300#define MAXSIZE 20480#define HOSTLEN 40#define CONNECTNUM 5// define 2 socket structstruct transocket{SOCKET fd1;SOCKET fd2;};// define functionvoid ver();void usage(char *prog);void transmitdata(LPVOID data);void getctrlc(int j);void closeallfd();void makelog(char *buffer, int length);void proxy(int port);void bind2bind(int port1, int port2);void bind2conn(int port1, char *host, int port2);void conn2conn(char *host1, int port1, char *host2, int port2);int testifisvalue(char *str);int create_socket();int create_server(int sockfd, int port);int client_connect(int sockfd, char* server, int port);// define GLOBAL variable hereextern int errno;FILE *fp;int method=0;//int connectnum=0;//************************************************************************************//// function main 主要是处理用户参数输入的问题////************************************************************************************VOID main(int argc, char* argv[]){char **p;char sConnectHost[HOSTLEN], sTransmitHost[HOSTLEN];int iConnectPort=0, iTransmitPort=0;char *logfile=NULL;ver();memset(sConnectHost, 0, HOSTLEN);memset(sTransmitHost, 0, HOSTLEN);p=argv;while(*p){if(stricmp(*p, "-log") == 0){if(testifisvalue(*(p+1))){logfile = *(++p);}else{printf("[-] ERROR: Must supply logfile name.\r\n");return;}p++;continue;}p++;}if(logfile !=NULL){fp=fopen(logfile,"a");if(fp == NULL ){printf("[-] ERROR: open logfile");return;}makelog("====== Start ======\r\n", 22);}// Win Start Winsock.WSADATA wsadata;WSAStartup(MAKEWORD(2, 2), &wsadata);signal(SIGINT, &getctrlc);if(argc > 2){if(stricmp(argv[1], "-listen") == 0 && argc >= 4){iConnectPort = atoi(argv[2]);iTransmitPort = atoi(argv[3]);method = 1;}elseif(stricmp(argv[1], "-tran") == 0 && argc >= 5){iConnectPort = atoi(argv[2]);strncpy(sTransmitHost, argv[3], HOSTLEN);iTransmitPort = atoi(argv[4]);method = 2;}elseif(stricmp(argv[1], "-slave") == 0 && argc >= 6){strncpy(sConnectHost, argv[2], HOSTLEN);iConnectPort = atoi(argv[3]);strncpy(sTransmitHost, argv[4], HOSTLEN);iTransmitPort = atoi(argv[5]);method = 3;}}switch(method){case 1:bind2bind(iConnectPort, iTransmitPort);break;case 2:bind2conn(iConnectPort, sTransmitHost, iTransmitPort);break;case 3:conn2conn(sConnectHost, iConnectPort, sTransmitHost, iTransmitPort);break;default:usage(argv[0]);break;}if(method){closeallfd();}WSACleanup();return;}//************************************************************************************//// print version message////************************************************************************************VOID ver(){printf("======================== HUC Packet Transmit Tool V%s =======================\r\n", VERSION);printf("=========== Code by lion & bkbll, Welcome to http://www.cnhonker.com==========\r\n\n");}//************************************************************************************//// print usage message////************************************************************************************VOID usage(char* prog){printf("[Usage of Packet Transmit:]\r\n");printf(" %s - [-log logfile]\n\n", prog);printf("[option:]\n");printf(" -listen \n");printf(" -tran \n");printf(" -slave \n\n");return;}//************************************************************************************//// test if is value////************************************************************************************int testifisvalue(char *str){if(str == NULL ) return(0);if(str[0]=='-') return(0);return(1);}//************************************************************************************//// LocalHost:ConnectPort transmit to LocalHost:TransmitPort////************************************************************************************void bind2bind(int port1, int port2){SOCKET fd1,fd2, sockfd1, sockfd2;struct sockaddr_in client1,client2;int size1,size2;HANDLE hThread=NULL;transocket sock;DWORD dwThreadID;if((fd1=create_socket())==0) return;if((fd2=create_socket())==0) return;printf("[+] Listening port %d ......\r\n",port1);fflush(stdout);if(create_server(fd1, port1)==0){closesocket(fd1);return;}printf("[+] Listen OK!\r\n");printf("[+] Listening port %d ......\r\n",port2);fflush(stdout);if(create_server(fd2, port2)==0){closesocket(fd2);return;}printf("[+] Listen OK!\r\n");size1=size2=sizeof(struct sockaddr);while(1){printf("[+] Waiting for Client on port:%d ......\r\n",port1);if((sockfd1 = accept(fd1,(struct sockaddr *)&client1,&size1))<0){printf("[-] Accept1 error.\r\n");continue;}printf("[+] Accept a Client on port %d from %s ......\r\n", port1, inet_ntoa(client1.sin_addr));printf("[+] Waiting another Client on port:%d....\r\n", port2);if((sockfd2 = accept(fd2, (struct sockaddr *)&client2, &size2))<0){printf("[-] Accept2 error.\r\n");closesocket(sockfd1);continue;}printf("[+] Accept a Client on port %d from %s\r\n",port2, inet_ntoa(client2.sin_addr));printf("[+] Accept Connect OK!\r\n");sock.fd1 = sockfd1;sock.fd2 = sockfd2;hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)transmitdata, (LPVOID)&sock, 0, &dwThreadID);if(hThread == NULL){TerminateThread(hThread, 0);return;}Sleep(1000);printf("[+] CreateThread OK!\r\n\n");}}//************************************************************************************//// LocalHost:ConnectPort transmit to TransmitHost:TransmitPort////************************************************************************************void bind2conn(int port1, char *host, int port2){SOCKET sockfd,sockfd1,sockfd2;struct sockaddr_in remote;int size;char buffer[1024];HANDLE hThread=NULL;transocket sock;DWORD dwThreadID;if (port1 > 65535 || port1 < 1){printf("[-] ConnectPort invalid.\r\n");return;}if (port2 > 65535 || port2 < 1){printf("[-] TransmitPort invalid.\r\n");return;}memset(buffer,0,1024);if((sockfd=create_socket()) == INVALID_SOCKET) return;if(create_server(sockfd, port1) == 0){closesocket(sockfd);return;}size=sizeof(struct sockaddr);while(1){printf("[+] Waiting for Client ......\r\n");if((sockfd1=accept(sockfd,(struct sockaddr *)&remote,&size))<0){printf("[-] Accept error.\r\n");continue;}printf("[+] Accept a Client from %s:%d ......\r\n",inet_ntoa(remote.sin_addr), ntohs(remote.sin_port));if((sockfd2=create_socket())==0){closesocket(sockfd1);continue;}printf("[+] Make a Connection to %s:%d ......\r\n",host,port2);fflush(stdout);if(client_connect(sockfd2,host,port2)==0){closesocket(sockfd2);sprintf(buffer,"[SERVER]connection to %s:%d error\r\n", host, port2);send(sockfd1,buffer,strlen(buffer),0);memset(buffer, 0, 1024);closesocket(sockfd1);continue;}printf("[+] Connect OK!\r\n");sock.fd1 = sockfd1;sock.fd2 = sockfd2;hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)transmitdata, (LPVOID)&sock, 0, &dwThreadID);if(hThread == NULL){TerminateThread(hThread, 0);return;}Sleep(1000);printf("[+] CreateThread OK!\r\n\n");}}//************************************************************************************//// ConnectHost:ConnectPort transmit to TransmitHost:TransmitPort////************************************************************************************void conn2conn(char *host1,int port1,char *host2,int port2){SOCKET sockfd1,sockfd2;HANDLE hThread=NULL;transocket sock;DWORD dwThreadID;fd_set fds;int l;char buffer[MAXSIZE];while(1){if((sockfd1=create_socket())==0) return;if((sockfd2=create_socket())==0) return;printf("[+] Make a Connection to %s:%d....\r\n",host1,port1);fflush(stdout);if(client_connect(sockfd1,host1,port1)==0){closesocket(sockfd1);closesocket(sockfd2);continue;}// fix by bkbll// if host1:port1 recved data, than connect to host2,port2l=0;memset(buffer,0,MAXSIZE);while(1){FD_ZERO(&fds);FD_SET(sockfd1, &fds);if (select(sockfd1+1, &fds, NULL, NULL, NULL) == SOCKET_ERROR){if (errno == WSAEINTR) continue;break;}if (FD_ISSET(sockfd1, &fds)){l=recv(sockfd1, buffer, MAXSIZE, 0);break;}Sleep(5);}if(l<=0){printf("[-] There is a error...Create a new connection.\r\n");continue;}while(1){printf("[+] Connect OK!\r\n");printf("[+] Make a Connection to %s:%d....\r\n", host2,port2);fflush(stdout);if(client_connect(sockfd2,host2,port2)==0){closesocket(sockfd1);closesocket(sockfd2);continue;}if(send(sockfd2,buffer,l,0)==SOCKET_ERROR){printf("[-] Send failed.\r\n");continue;}l=0;memset(buffer,0,MAXSIZE);break;}printf("[+] All Connect OK!\r\n");sock.fd1 = sockfd1;sock.fd2 = sockfd2;hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)transmitdata, (LPVOID)&sock, 0, &dwThreadID);if(hThread == NULL){TerminateThread(hThread, 0);return;}// connectnum++;Sleep(1000);printf("[+] CreateThread OK!\r\n\n");}}//************************************************************************************//// Socket Transmit to Socket////************************************************************************************void transmitdata(LPVOID data){SOCKET fd1, fd2;transocket *sock;struct timeval timeset;fd_set readfd,writefd;int result,i=0;char read_in1[MAXSIZE],send_out1[MAXSIZE];char read_in2[MAXSIZE],send_out2[MAXSIZE];int read1=0,totalread1=0,send1=0;int read2=0,totalread2=0,send2=0;int sendcount1,sendcount2;int maxfd;struct sockaddr_in client1,client2;int structsize1,structsize2;char host1[20],host2[20];int port1=0,port2=0;char tmpbuf[100];sock = (transocket *)data;fd1 = sock->fd1;fd2 = sock->fd2;memset(host1,0,20);memset(host2,0,20);memset(tmpbuf,0,100);structsize1=sizeof(struct sockaddr);structsize2=sizeof(struct sockaddr);if(getpeername(fd1,(struct sockaddr *)&client1,&structsize1)<0){strcpy(host1, "fd1");}else{// printf("[+]got, ip:%s, port:%d\r\n",inet_ntoa(client1.sin_addr),ntohs(client1.sin_port));strcpy(host1, inet_ntoa(client1.sin_addr));port1=ntohs(client1.sin_port);}if(getpeername(fd2,(struct sockaddr *)&client2,&structsize2)<0){strcpy(host2,"fd2");}else{// printf("[+]got, ip:%s, port:%d\r\n",inet_ntoa(client2.sin_addr),ntohs(client2.sin_port));strcpy(host2, inet_ntoa(client2.sin_addr));port2=ntohs(client2.sin_port);}printf("[+] Start Transmit (%s:%d <-> %s:%d) ......\r\n\n", host1, port1, host2, port2);maxfd=max(fd1,fd2)+1;memset(read_in1,0,MAXSIZE);memset(read_in2,0,MAXSIZE);memset(send_out1,0,MAXSIZE);memset(send_out2,0,MAXSIZE);timeset.tv_sec=TIMEOUT;timeset.tv_usec=0;while(1){FD_ZERO(&readfd);FD_ZERO(&writefd);FD_SET((UINT)fd1, &readfd);FD_SET((UINT)fd1, &writefd);FD_SET((UINT)fd2, &writefd);FD_SET((UINT)fd2, &readfd);result=select(maxfd,&readfd,&writefd,NULL,×et);if((result<0) && (errno!=EINTR)){printf("[-] Select error.\r\n");break;}else if(result==0){printf("[-] Socket time out.\r\n");break;}if(FD_ISSET(fd1, &readfd)){/* must < MAXSIZE-totalread1, otherwise send_out1 will flow */if(totalread1 < MAXSIZE) {read1=recv(fd1, read_in1, MAXSIZE-totalread1, 0);if((read1==SOCKET_ERROR) || (read1==0)){printf("[-] Read fd1 data error,maybe close?\r\n");break;}memcpy(send_out1+totalread1,read_in1,read1);sprintf(tmpbuf,"\r\nRecv %5d bytes from %s:%d\r\n", read1, host1, port1);printf(" Recv %5d bytes %16s:%d\r\n", read1, host1, port1);makelog(tmpbuf,strlen(tmpbuf));makelog(read_in1,read1);totalread1+=read1;memset(read_in1,0,MAXSIZE);}}if(FD_ISSET(fd2, &writefd)){int err=0;sendcount1=0;while(totalread1>0){send1=send(fd2, send_out1+sendcount1, totalread1, 0);if(send1==0)break;if((send1<0) && (errno!=EINTR)){printf("[-] Send to fd2 unknow error.\r\n");err=1;break;}if((send1<0) && (errno==ENOSPC)) break;sendcount1+=send1;totalread1-=send1;printf(" Send %5d bytes %16s:%d\r\n", send1, host2, port2);}if(err==1) break;if((totalread1>0) && (sendcount1>0)){/* move not sended data to start addr */memcpy(send_out1,send_out1+sendcount1,totalread1);memset(send_out1+totalread1,0,MAXSIZE-totalread1);}elsememset(send_out1,0,MAXSIZE);}if(FD_ISSET(fd2, &readfd)){if(totalread2 < MAXSIZE) {read2=recv(fd2,read_in2,MAXSIZE-totalread2, 0);if(read2==0)break;if((read2<0) && (errno!=EINTR)){printf("[-] Read fd2 data error,maybe close?\r\n\r\n");break;}memcpy(send_out2+totalread2,read_in2,read2);sprintf(tmpbuf, "\r\nRecv %5d bytes from %s:%d\r\n", read2, host2, port2);printf(" Recv %5d bytes %16s:%d\r\n", read2, host2, port2);makelog(tmpbuf,strlen(tmpbuf));makelog(read_in2,read2);totalread2+=read2;memset(read_in2,0,MAXSIZE);}}if(FD_ISSET(fd1, &writefd)){int err2=0;sendcount2=0;while(totalread2>0){send2=send(fd1, send_out2+sendcount2, totalread2, 0);if(send2==0)break;if((send2<0) && (errno!=EINTR)){printf("[-] Send to fd1 unknow error.\r\n");err2=1;break;}if((send2<0) && (errno==ENOSPC)) break;sendcount2+=send2;totalread2-=send2;printf(" Send %5d bytes %16s:%d\r\n", send2, host1, port1);}if(err2==1) break;if((totalread2>0) && (sendcount2 > 0)){/* move not sended data to start addr */memcpy(send_out2, send_out2+sendcount2, totalread2);memset(send_out2+totalread2, 0, MAXSIZE-totalread2);}elsememset(send_out2,0,MAXSIZE);}Sleep(5);}closesocket(fd1);closesocket(fd2);// if(method == 3)// connectnum --;printf("\r\n[+] OK! I Closed The Two Socket.\r\n");}void getctrlc(int j){printf("\r\n[-] Received Ctrl+C\r\n");closeallfd();exit(0);}void closeallfd(){int i;printf("[+] Let me exit ......\r\n");fflush(stdout);for(i=3; i<256; i++){closesocket(i);}if(fp != NULL){fprintf(fp,"\r\n====== Exit ======\r\n");fclose(fp);}printf("[+] All Right!\r\n");}int create_socket(){int sockfd;sockfd=socket(AF_INET,SOCK_STREAM,0);if(sockfd<0){printf("[-] Create socket error.\r\n");return(0);}return(sockfd);}int create_server(int sockfd,int port){struct sockaddr_in srvaddr;int on=1;memset(&srvaddr, 0, sizeof(struct sockaddr));srvaddr.sin_port=htons(port);srvaddr.sin_family=AF_INET;srvaddr.sin_addr.s_addr=htonl(INADDR_ANY);setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR, (char*)&on,sizeof(on)); //so I can rebind the portif(bind(sockfd,(struct sockaddr *)&srvaddr,sizeof(struct sockaddr))<0){printf("[-] Socket bind error.\r\n");return(0);}if(listen(sockfd,CONNECTNUM)<0){printf("[-] Socket Listen error.\r\n");return(0);}return(1);}int client_connect(int sockfd,char* server,int port){struct sockaddr_in cliaddr;struct hostent *host;if(!(host=gethostbyname(server))){printf("[-] Gethostbyname(%s) error:%s\n",server,strerror(errno));return(0);}memset(&cliaddr, 0, sizeof(struct sockaddr));cliaddr.sin_family=AF_INET;cliaddr.sin_port=htons(port);cliaddr.sin_addr=*((struct in_addr *)host->h_addr);if(connect(sockfd,(struct sockaddr *)&cliaddr,sizeof(struct sockaddr))<0){printf("[-] Connect error.\r\n");return(0);}return(1);}void makelog(char *buffer,int length){if(fp !=NULL){// fprintf(fp, "%s", buffer);// printf("%s",buffer);write(fileno(fp),buffer,length);// fflush(fp);}}
附上效果图一张：
Windows7 64+VS2013编译通过的源码：
/*************************************************************************************** PortTrans.cpp - Port Forwarding.** Copyright (C) 2015 HUC All Rights Reserved.** Author : pandas* :* :* Date : 2015-4-9* :* Complie : cl PortTrans.cpp* :* Usage : D:\>PortTrans* : ======================== Port Forwarding Tool V1.00 =======================* : ========================== Improved by pandas ===========================* :* : [Usage of Port Forwarding:]* : PortTrans - [-log logfile]* :* : [option:]* : -listen* : -tran* : -slave**************************************************************************************/#define _WINSOCK_DEPRECATED_NO_WARNINGS#define _CRT_SECURE_NO_WARNINGS#include <stdio.h>#include <stdlib.h>#include <winsock2.h>#include <signal.h>#include <errno.h>#include <io.h>#pragma comment(lib, "ws2_32.lib")#define VERSION "1.00"#define TIMEOUT 300#define MAXSIZE 20480#define HOSTLEN 40#define CONNECTNUM 5// define 2 socket structstruct transocket{SOCKET fd1;SOCKET fd2;};// define functionvoid ver();void usage(char *prog);void transmitdata(LPVOID data);void getctrlc(int j);void closeallfd();void makelog(char *buffer, int length);void proxy(int port);void bind2bind(int port1, int port2);void bind2conn(int port1, char *host, int port2);void conn2conn(char *host1, int port1, char *host2, int port2);int testifisvalue(char *str);int create_socket();int create_server(int sockfd, int port);int client_connect(int sockfd, char* server, int port);// define GLOBAL variable here//int error;FILE *fp;int method = 0;//int connectnum=0;//************************************************************************************//// function main 主要是处理用户参数输入的问题////************************************************************************************VOID main(int argc, char* argv[]){char **p;char sConnectHost[HOSTLEN], sTransmitHost[HOSTLEN];int iConnectPort = 0, iTransmitPort = 0;char *logfile = NULL;errno_t err;ver();memset(sConnectHost, 0, HOSTLEN);memset(sTransmitHost, 0, HOSTLEN);p = argv;while (*p){if (_stricmp(*p, "-log") == 0){if (testifisvalue(*(p + 1))){logfile = *(++p);}else{printf("[-] ERROR: Must supply logfile name.\r\n");return;}//p++;continue;}p++;}if (logfile != NULL){//fp = fopen(logfile, "a");err = fopen_s(&fp, logfile, "a");if (fp == NULL){printf("[-] ERROR: open logfile");return;}makelog("====== Start ======\r\n", 22);}// Win Start Winsock.WSADATA wsadata;WSAStartup(MAKEWORD(2, 2), &wsadata);signal(SIGINT, &getctrlc);if (argc > 2){if (_stricmp(argv[1], "-listen") == 0 && argc >= 4){iConnectPort = atoi(argv[2]);iTransmitPort = atoi(argv[3]);method = 1;}elseif (_stricmp(argv[1], "-tran") == 0 && argc >= 5){iConnectPort = atoi(argv[2]);strncpy_s(sTransmitHost, argv[3], HOSTLEN);iTransmitPort = atoi(argv[4]);method = 2;}elseif (_stricmp(argv[1], "-slave") == 0 && argc >= 6){strncpy_s(sConnectHost, argv[2], HOSTLEN);iConnectPort = atoi(argv[3]);strncpy_s(sTransmitHost, argv[4], HOSTLEN);iTransmitPort = atoi(argv[5]);method = 3;}}switch (method){case 1:bind2bind(iConnectPort, iTransmitPort);break;case 2:bind2conn(iConnectPort, sTransmitHost, iTransmitPort);break;case 3:conn2conn(sConnectHost, iConnectPort, sTransmitHost, iTransmitPort);break;default:usage(argv[0]);break;}if (method){closeallfd();}WSACleanup();return;}//************************************************************************************//// print version message////************************************************************************************VOID ver(){printf("======================== Port Forwarding Tool V%s =======================\r\n", VERSION);printf("========================== Improved by pandas ===========================\r\n\n");}//************************************************************************************//// print usage message////************************************************************************************VOID usage(char* prog){printf("[Usage of Packet Transmit:]\r\n");printf(" %s - [-log logfile]\n\n", prog);printf("[option:]\n");printf(" -listen \n");printf(" -tran \n");printf(" -slave \n\n");return;}//************************************************************************************//// test if is value////************************************************************************************int testifisvalue(char *str){if (str == NULL) return(0);if (str[0] == '-') return(0);return(1);}//************************************************************************************//// LocalHost:ConnectPort transmit to LocalHost:TransmitPort////************************************************************************************void bind2bind(int port1, int port2){SOCKET fd1, fd2, sockfd1, sockfd2;struct sockaddr_in client1, client2;int size1, size2;HANDLE hThread = NULL;transocket sock;DWORD dwThreadID;if ((fd1 = create_socket()) == 0) return;if ((fd2 = create_socket()) == 0) return;printf("[+] Listening port %d ......\r\n", port1);fflush(stdout);if (create_server(fd1, port1) == 0){closesocket(fd1);return;}printf("[+] Listen OK!\r\n");printf("[+] Listening port %d ......\r\n", port2);fflush(stdout);if (create_server(fd2, port2) == 0){closesocket(fd2);return;}printf("[+] Listen OK!\r\n");size1 = size2 = sizeof(struct sockaddr);while (1){printf("[+] Waiting for Client on port:%d ......\r\n", port1);if ((sockfd1 = accept(fd1, (struct sockaddr *)&client1, &size1))<0){printf("[-] Accept1 error.\r\n");continue;}printf("[+] Accept a Client on port %d from %s ......\r\n", port1, inet_ntoa(client1.sin_addr));printf("[+] Waiting another Client on port:%d....\r\n", port2);if ((sockfd2 = accept(fd2, (struct sockaddr *)&client2, &size2))<0){printf("[-] Accept2 error.\r\n");closesocket(sockfd1);continue;}printf("[+] Accept a Client on port %d from %s\r\n", port2, inet_ntoa(client2.sin_addr));printf("[+] Accept Connect OK!\r\n");sock.fd1 = sockfd1;sock.fd2 = sockfd2;hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)transmitdata, (LPVOID)&sock, 0, &dwThreadID);if (hThread == NULL){TerminateThread(hThread, 0);return;}Sleep(1000);printf("[+] CreateThread OK!\r\n\n");}}//************************************************************************************//// LocalHost:ConnectPort transmit to TransmitHost:TransmitPort////************************************************************************************void bind2conn(int port1, char *host, int port2){SOCKET sockfd, sockfd1, sockfd2;struct sockaddr_in remote;int size;char buffer[1024];HANDLE hThread = NULL;transocket sock;DWORD dwThreadID;if (port1 > 65535 || port1 < 1){printf("[-] ConnectPort invalid.\r\n");return;}if (port2 > 65535 || port2 < 1){printf("[-] TransmitPort invalid.\r\n");return;}memset(buffer, 0, 1024);if ((sockfd = create_socket()) == INVALID_SOCKET) return;if (create_server(sockfd, port1) == 0){closesocket(sockfd);return;}size = sizeof(struct sockaddr);while (1){printf("[+] Waiting for Client ......\r\n");if ((sockfd1 = accept(sockfd, (struct sockaddr *)&remote, &size))<0){printf("[-] Accept error.\r\n");continue;}printf("[+] Accept a Client from %s:%d ......\r\n",inet_ntoa(remote.sin_addr), ntohs(remote.sin_port));if ((sockfd2 = create_socket()) == 0){closesocket(sockfd1);continue;}printf("[+] Make a Connection to %s:%d ......\r\n", host, port2);fflush(stdout);if (client_connect(sockfd2, host, port2) == 0){closesocket(sockfd2);sprintf_s(buffer, "[SERVER]connection to %s:%d error\r\n", host, port2);send(sockfd1, buffer, strlen(buffer), 0);memset(buffer, 0, 1024);closesocket(sockfd1);continue;}printf("[+] Connect OK!\r\n");sock.fd1 = sockfd1;sock.fd2 = sockfd2;hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)transmitdata, (LPVOID)&sock, 0, &dwThreadID);if (hThread == NULL){TerminateThread(hThread, 0);return;}Sleep(1000);printf("[+] CreateThread OK!\r\n\n");}}//************************************************************************************//// ConnectHost:ConnectPort transmit to TransmitHost:TransmitPort////************************************************************************************void conn2conn(char *host1, int port1, char *host2, int port2){SOCKET sockfd1, sockfd2;HANDLE hThread = NULL;transocket sock;DWORD dwThreadID;fd_set fds;int l;char buffer[MAXSIZE];while (1){/*while(connectnum){if(connectnum < CONNECTNUM){Sleep(10000);break;}else{Sleep(TIMEOUT*1000);continue;}}*/if ((sockfd1 = create_socket()) == 0) return;if ((sockfd2 = create_socket()) == 0) return;printf("[+] Make a Connection to %s:%d....\r\n", host1, port1);fflush(stdout);if (client_connect(sockfd1, host1, port1) == 0){closesocket(sockfd1);closesocket(sockfd2);continue;}// fix by bkbll// if host1:port1 recved data, than connect to host2,port2l = 0;memset(buffer, 0, MAXSIZE);while (1){FD_ZERO(&fds);FD_SET(sockfd1, &fds);if (select(sockfd1 + 1, &fds, NULL, NULL, NULL) == SOCKET_ERROR){if (errno== WSAEINTR) continue;break;}if (FD_ISSET(sockfd1, &fds)){l = recv(sockfd1, buffer, MAXSIZE, 0);break;}Sleep(5);}if (l <= 0){printf("[-] There is a error...Create a new connection.\r\n");continue;}while (1){printf("[+] Connect OK!\r\n");printf("[+] Make a Connection to %s:%d....\r\n", host2, port2);fflush(stdout);if (client_connect(sockfd2, host2, port2) == 0){closesocket(sockfd1);closesocket(sockfd2);continue;}if (send(sockfd2, buffer, l, 0) == SOCKET_ERROR){printf("[-] Send failed.\r\n");continue;}l = 0;memset(buffer, 0, MAXSIZE);break;}printf("[+] All Connect OK!\r\n");sock.fd1 = sockfd1;sock.fd2 = sockfd2;hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)transmitdata, (LPVOID)&sock, 0, &dwThreadID);if (hThread == NULL){TerminateThread(hThread, 0);return;}// connectnum++;Sleep(1000);printf("[+] CreateThread OK!\r\n\n");}}//************************************************************************************//// Socket Transmit to Socket////************************************************************************************void transmitdata(LPVOID data){SOCKET fd1, fd2;transocket *sock;struct timeval timeset;fd_set readfd, writefd;int result, i = 0;char read_in1[MAXSIZE], send_out1[MAXSIZE];char read_in2[MAXSIZE], send_out2[MAXSIZE];int read1 = 0, totalread1 = 0, send1 = 0;int read2 = 0, totalread2 = 0, send2 = 0;int sendcount1, sendcount2;int maxfd;struct sockaddr_in client1, client2;int structsize1, structsize2;char host1[20], host2[20];int port1 = 0, port2 = 0;char tmpbuf[100];sock = (transocket *)data;fd1 = sock->fd1;fd2 = sock->fd2;memset(host1, 0, 20);memset(host2, 0, 20);memset(tmpbuf, 0, 100);structsize1 = sizeof(struct sockaddr);structsize2 = sizeof(struct sockaddr);if (getpeername(fd1, (struct sockaddr *)&client1, &structsize1)<0){strcpy_s(host1, "fd1");}else{// printf("[+]got, ip:%s, port:%d\r\n",inet_ntoa(client1.sin_addr),ntohs(client1.sin_port));strcpy_s(host1, inet_ntoa(client1.sin_addr));port1 = ntohs(client1.sin_port);}if (getpeername(fd2, (struct sockaddr *)&client2, &structsize2)<0){strcpy_s(host2, "fd2");}else{// printf("[+]got, ip:%s, port:%d\r\n",inet_ntoa(client2.sin_addr),ntohs(client2.sin_port));strcpy_s(host2, inet_ntoa(client2.sin_addr));port2 = ntohs(client2.sin_port);}printf("[+] Start Transmit (%s:%d <-> %s:%d) ......\r\n\n", host1, port1, host2, port2);maxfd = max(fd1, fd2) + 1;memset(read_in1, 0, MAXSIZE);memset(read_in2, 0, MAXSIZE);memset(send_out1, 0, MAXSIZE);memset(send_out2, 0, MAXSIZE);timeset.tv_sec = TIMEOUT;timeset.tv_usec = 0;while (1){FD_ZERO(&readfd);FD_ZERO(&writefd);FD_SET((UINT)fd1, &readfd);FD_SET((UINT)fd1, &writefd);FD_SET((UINT)fd2, &writefd);FD_SET((UINT)fd2, &readfd);result = select(maxfd, &readfd, &writefd, NULL, ×et);if ((result<0) && (errno!= EINTR)){printf("[-] Select error.\r\n");break;}else if (result == 0){printf("[-] Socket time out.\r\n");break;}if (FD_ISSET(fd1, &readfd)){/* must < MAXSIZE-totalread1, otherwise send_out1 will flow */if (totalread1 < MAXSIZE) {read1 = recv(fd1, read_in1, MAXSIZE - totalread1, 0);if ((read1 == SOCKET_ERROR) || (read1 == 0)){printf("[-] Read fd1 data error,maybe close?\r\n");break;}memcpy(send_out1 + totalread1, read_in1, read1);sprintf_s(tmpbuf, "\r\nRecv %5d bytes from %s:%d\r\n", read1, host1, port1);printf(" Recv %5d bytes %16s:%d\r\n", read1, host1, port1);makelog(tmpbuf, strlen(tmpbuf));makelog(read_in1, read1);totalread1 += read1;memset(read_in1, 0, MAXSIZE);}}if (FD_ISSET(fd2, &writefd)){int err = 0;sendcount1 = 0;while (totalread1>0){send1 = send(fd2, send_out1 + sendcount1, totalread1, 0);if (send1 == 0)break;if ((send1<0) && (errno != EINTR)){printf("[-] Send to fd2 unknow error.\r\n");err = 1;break;}if ((send1<0) && (errno == ENOSPC)) break;sendcount1 += send1;totalread1 -= send1;printf(" Send %5d bytes %16s:%d\r\n", send1, host2, port2);}if (err == 1) break;if ((totalread1>0) && (sendcount1>0)){/* move not sended data to start addr */memcpy(send_out1, send_out1 + sendcount1, totalread1);memset(send_out1 + totalread1, 0, MAXSIZE - totalread1);}elsememset(send_out1, 0, MAXSIZE);}if (FD_ISSET(fd2, &readfd)){if (totalread2 < MAXSIZE) {read2 = recv(fd2, read_in2, MAXSIZE - totalread2, 0);if (read2 == 0)break;if ((read2<0) && (errno != EINTR)){printf("[-] Read fd2 data error,maybe close?\r\n\r\n");break;}memcpy(send_out2 + totalread2, read_in2, read2);sprintf_s(tmpbuf, "\r\nRecv %5d bytes from %s:%d\r\n", read2, host2, port2);printf(" Recv %5d bytes %16s:%d\r\n", read2, host2, port2);makelog(tmpbuf, strlen(tmpbuf));makelog(read_in2, read2);totalread2 += read2;memset(read_in2, 0, MAXSIZE);}}if (FD_ISSET(fd1, &writefd)){int err2 = 0;sendcount2 = 0;while (totalread2>0){send2 = send(fd1, send_out2 + sendcount2, totalread2, 0);if (send2 == 0)break;if ((send2<0) && (errno != EINTR)){printf("[-] Send to fd1 unknow error.\r\n");err2 = 1;break;}if ((send2<0) && (errno == ENOSPC)) break;sendcount2 += send2;totalread2 -= send2;printf(" Send %5d bytes %16s:%d\r\n", send2, host1, port1);}if (err2 == 1) break;if ((totalread2>0) && (sendcount2 > 0)){/* move not sended data to start addr */memcpy(send_out2, send_out2 + sendcount2, totalread2);memset(send_out2 + totalread2, 0, MAXSIZE - totalread2);}elsememset(send_out2, 0, MAXSIZE);}Sleep(5);}closesocket(fd1);closesocket(fd2);// if(method == 3)// connectnum --;printf("\r\n[+] OK! I Closed The Two Socket.\r\n");}void getctrlc(int j){printf("\r\n[-] Received Ctrl+C\r\n");closeallfd();exit(0);}void closeallfd(){int i;printf("[+] Let me exit ......\r\n");fflush(stdout);for (i = 3; i<256; i++){closesocket(i);}if (fp != NULL){fprintf(fp, "\r\n====== Exit ======\r\n");fclose(fp);}printf("[+] All Right!\r\n");}int create_socket(){int sockfd;sockfd = socket(AF_INET, SOCK_STREAM, 0);if (sockfd<0){printf("[-] Create socket error.\r\n");return(0);}return(sockfd);}int create_server(int sockfd, int port){struct sockaddr_in srvaddr;int on = 1;memset(&srvaddr, 0, sizeof(struct sockaddr));srvaddr.sin_port = htons(port);srvaddr.sin_family = AF_INET;srvaddr.sin_addr.s_addr = htonl(INADDR_ANY);setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char*)&on, sizeof(on)); //so I can rebind the portif (bind(sockfd, (struct sockaddr *)&srvaddr, sizeof(struct sockaddr))<0){printf("[-] Socket bind error.\r\n");return(0);}if (listen(sockfd, CONNECTNUM)<0){printf("[-] Socket Listen error.\r\n");return(0);}return(1);}int client_connect(int sockfd, char* server, int port){struct sockaddr_in cliaddr;struct hostent *host;if (!(host = gethostbyname(server))){printf("[-] Gethostbyname(%s) error:%s\n", server, strerror(errno));return(0);}memset(&cliaddr, 0, sizeof(struct sockaddr));cliaddr.sin_family = AF_INET;cliaddr.sin_port = htons(port);cliaddr.sin_addr = *((struct in_addr *)host->h_addr);if (connect(sockfd, (struct sockaddr *)&cliaddr, sizeof(struct sockaddr))<0){printf("[-] Connect error.\r\n");return(0);}return(1);}void makelog(char *buffer, int length){if (fp != NULL){_write(_fileno(fp), buffer, length);}}
注意，VS2013编译出来的程序在其他计算机上运行时，可能出现如下问题：
这是由于需要MSVCR120.dll这个动态链接库来支持C函数库和C++的STL标准库。对于这个问题的解决方法是：可以把C/C++运行时库MSVCR120编译到你的exe里，这样你的程序复制到任意windows上就能直接运行了。项目 - 属性 - 配置属性 - C/C++ - 代码生成 - 运行库 - 多线程(/MT)。这样生成的EXE会增大一些，取决于你用到了多少库函数。具体设置如下图所示：
最后，附上效果图一张：
采用这种方式进行端口转发，其实速度有些慢，有时候会比较卡。对于Web端口转发工具及HTTP版本的LCX，后续我再分析一下。
以上源码仅供学习之用，请不要用于非法途径。
