Datapipe.c TCP/IP套接字重定向

Question

我試圖讓這段代碼工作，但它在命令行參數中引發了一個錯誤。由於argc！= 5，它不會繼續執行程序。我知道（嗯，我想）我需要指定無論是在本地主機上運行，​​遠程主機等下面的代碼，從https://github.com/bovine/datapipe

#pragma comment (lib, "Ws2_32.lib") 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <errno.h> 
#include <time.h> 
#if defined(__WIN32__) || defined(WIN32) || defined(_WIN32) 
    #define WIN32_LEAN_AND_MEAN 
    #include <winsock.h> 
    #define bzero(p, l) memset(p, 0, l) 
    #define bcopy(s, t, l) memmove(t, s, l) 
#else 
    #include <sys/time.h> 
    #include <sys/types.h> 
    #include <sys/socket.h> 
    #include <sys/wait.h> 
    #include <netinet/in.h> 
    #include <arpa/inet.h> 
    #include <unistd.h> 
    #include <netdb.h> 
    #include <strings.h> 
    #define recv(x,y,z,a) read(x,y,z) 
    #define send(x,y,z,a) write(x,y,z) 
    #define closesocket(s) close(s) 
    typedef int SOCKET; 
#endif 

#ifndef INADDR_NONE 
#define INADDR_NONE 0xffffffff 
#endif 


struct client_t 
{ 
    int inuse; 
    SOCKET csock, osock; 
    time_t activity; 
}; 

#define MAXCLIENTS 20 
#define IDLETIMEOUT 300 


const char ident[] = "$Id: datapipe.c,v 1.8 1999/01/29 01:21:54 jlawson Exp $"; 

int main(int argc, char *argv[]) 
{ 
    SOCKET lsock; 
    char buf[4096]; 
    struct sockaddr_in laddr, oaddr; 
    int i; 
    struct client_t clients[MAXCLIENTS]; 


#if defined(__WIN32__) || defined(WIN32) || defined(_WIN32) 
    /* Winsock needs additional startup activities */ 
    WSADATA wsadata; 
    WSAStartup(MAKEWORD(1,1), &wsadata); 
#endif 


    /* check number of command line arguments */ 
    if (argc != 5) { 
    fprintf(stderr,"Usage: %s localhost localport remotehost remoteport\n",argv[0]); 
    system ("pause"); 
    return 30; 
    } 


    /* reset all of the client structures */ 
    for (i = 0; i < MAXCLIENTS; i++) 
    clients[i].inuse = 0; 


    /* determine the listener address and port */ 
    bzero(&laddr, sizeof(struct sockaddr_in)); 
    laddr.sin_family = AF_INET; 
    laddr.sin_port = htons((unsigned short) atol(argv[2])); 
    laddr.sin_addr.s_addr = inet_addr(argv[1]); 
    if (!laddr.sin_port) { 
    fprintf(stderr, "invalid listener port\n"); 
    system ("pause"); 
    return 20; 
    } 
    if (laddr.sin_addr.s_addr == INADDR_NONE) { 
    struct hostent *n; 
    if ((n = gethostbyname(argv[1])) == NULL) { 
     perror("gethostbyname"); 
      system ("pause"); 
     return 20; 
    }  
    bcopy(n->h_addr, (char *) &laddr.sin_addr, n->h_length); 
    } 


    /* determine the outgoing address and port */ 
    bzero(&oaddr, sizeof(struct sockaddr_in)); 
    oaddr.sin_family = AF_INET; 
    oaddr.sin_port = htons((unsigned short) atol(argv[4])); 
    if (!oaddr.sin_port) { 
    fprintf(stderr, "invalid target port\n"); 
    system ("pause"); 
    return 25; 
    } 
    oaddr.sin_addr.s_addr = inet_addr(argv[3]); 
    if (oaddr.sin_addr.s_addr == INADDR_NONE) { 
    struct hostent *n; 
    if ((n = gethostbyname(argv[3])) == NULL) { 
     perror("gethostbyname"); 
     system ("pause"); 
     return 25; 
    }  
    bcopy(n->h_addr, (char *) &oaddr.sin_addr, n->h_length); 
    } 


    /* create the listener socket */ 
    if ((lsock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { 
    perror("socket"); 
    system ("pause"); 
    return 20; 
    } 
    if (bind(lsock, (struct sockaddr *)&laddr, sizeof(laddr))) { 
    perror("bind"); 
    system ("pause"); 
    return 20; 
    } 
    if (listen(lsock, 5)) { 
    perror("listen"); 
system ("pause"); 
    return 20; 
    } 


    /* change the port in the listener struct to zero, since we will 
    * use it for binding to outgoing local sockets in the future. */ 
    laddr.sin_port = htons(0); 


    /* fork off into the background. */ 
#if !defined(__WIN32__) && !defined(WIN32) && !defined(_WIN32) 
    if ((i = fork()) == -1) { 
    perror("fork"); 
    system ("pause"); 
    return 20; 
    } 
    if (i > 0) 
    return 0; 
    setsid(); 
#endif 


    /* main polling loop. */ 
    while (1) 
    { 
    fd_set fdsr; 
    int maxsock; 
    struct timeval tv = {1,0}; 
    time_t now = time(NULL); 

    /* build the list of sockets to check. */ 
    FD_ZERO(&fdsr); 
    FD_SET(lsock, &fdsr); 
    maxsock = (int) lsock; 
for (i = 0; i < MAXCLIENTS; i++) 
    if (clients[i].inuse) { 
    FD_SET(clients[i].csock, &fdsr); 
    if ((int) clients[i].csock > maxsock) 
     maxsock = (int) clients[i].csock; 
    FD_SET(clients[i].osock, &fdsr); 
    if ((int) clients[i].osock > maxsock) 
     maxsock = (int) clients[i].osock; 
    }  
if (select(maxsock + 1, &fdsr, NULL, NULL, &tv) < 0) { 
    system ("pause"); 
    return 30; 
} 


/* check if there are new connections to accept. */ 
if (FD_ISSET(lsock, &fdsr)) 
{ 
    SOCKET csock = accept(lsock, NULL, 0); 

    for (i = 0; i < MAXCLIENTS; i++) 
    if (!clients[i].inuse) break; 
    if (i < MAXCLIENTS) 
    { 
    /* connect a socket to the outgoing host/port */ 
    SOCKET osock; 
    if ((osock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { 
     perror("socket"); 
     closesocket(csock); 
    } 
    else if (bind(osock, (struct sockaddr *)&laddr, sizeof(laddr))) { 
     perror("bind"); 
     closesocket(csock); 
     closesocket(osock); 
    } 
    else if (connect(osock, (struct sockaddr *)&oaddr, sizeof(oaddr))) { 
     perror("connect"); 
     closesocket(csock); 
     closesocket(osock); 
    } 
    else { 
     clients[i].osock = osock; 
     clients[i].csock = csock; 
     clients[i].activity = now; 
     clients[i].inuse = 1; 
    } 
    } else { 
    fprintf(stderr, "too many clients\n"); 
    closesocket(csock); 
    }   
} 


/* service any client connections that have waiting data. */ 
for (i = 0; i < MAXCLIENTS; i++) 
{ 
    int nbyt, closeneeded = 0; 
    if (!clients[i].inuse) { 
    continue; 
    } else if (FD_ISSET(clients[i].csock, &fdsr)) { 
    if ((nbyt = recv(clients[i].csock, buf, sizeof(buf), 0)) <= 0 || 
     send(clients[i].osock, buf, nbyt, 0) <= 0) closeneeded = 1; 
    else clients[i].activity = now; 
    } else if (FD_ISSET(clients[i].osock, &fdsr)) { 
    if ((nbyt = recv(clients[i].osock, buf, sizeof(buf), 0)) <= 0 || 
     send(clients[i].csock, buf, nbyt, 0) <= 0) closeneeded = 1; 
    else clients[i].activity = now; 
    } else if (now - clients[i].activity > IDLETIMEOUT) { 
    closeneeded = 1; 
    } 
    if (closeneeded) { 
    closesocket(clients[i].csock); 
    closesocket(clients[i].osock); 
    clients[i].inuse = 0; 
     }  
    } 

    } 
    system ("pause"); 
    return 0; 
} 

我只需要找到一種方法，使工作和使用拉所以我可以剖析它。不幸的是，我不知道應該如何設置argc = 5，或者如何確定它運行的是什麼（localhost，localport，remotehost，remoteport）。

非常感謝您的幫助。

Answer 1

運行它。它會輸出用法信息：

if (argc != 5) { 
    fprintf(stderr,"Usage: %s localhost localport remotehost remoteport\n",argv[0]); 
    system ("pause"); 
    return 30; 
} 

我推測，一個例子來看可能是./datapipe 10.0.0.1 1337 10.0.0.3 1234，其中10.0.0.1是本地IP地址，10.0.0.3是遠程主機。