[Network] Telnet 예제

[Telnet Server Code]

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <WinSock2.h>
#include <process.h>
#include <windows.h>
 
int main()
{
    WSADATA wsdata;
    WSAStartup(MAKEWORD(2,2),&wsdata);
    SOCKET servSock = socket(AF_INET,SOCK_STREAM,0);
    SOCKADDR_IN servAddr;
    ZeroMemory(&servAddr, sizeof(servAddr));
    servAddr.sin_family = AF_INET;
    servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servAddr.sin_port = htons(12345);
    bind(servSock,(SOCKADDR*)&servAddr,sizeof(SOCKADDR_IN));
    listen(servSock,5);
 
    SOCKET clntSock = accept(servSock,NULL,NULL);
    int fileLen;
    char cmd[20] = {0};
    recv(clntSock, cmd, sizeof(cmd), 0);
 
    char buf[100];
    ZeroMemory(&buf, sizeof(buf));
    FILE *p = _popen(cmd, "r");
    while(1){
        fileLen = fread(buf,1,20,p);
        send(clntSock,buf,fileLen,0);
        if(feof(p))
            break;        
    }
    fclose(p);
    closesocket(clntSock);
    closesocket(servSock);
    WSACleanup();
    return 0;
}

[Telnet Client Code]

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <WinSock2.h>
#include <process.h>
#include <windows.h>
        
int main(){
    WSADATA wsdata;
    WSAStartup(MAKEWORD(2,2),&wsdata);
    SOCKET sock = socket(PF_INET,SOCK_STREAM,0);;
    SOCKADDR_IN servAddr;
    ZeroMemory(&servAddr, sizeof(servAddr));
    servAddr.sin_family = AF_INET;
    servAddr.sin_addr.s_addr = inet_addr("61.109.203.93");
    servAddr.sin_port = htons(12345);
 
    char data[30];
    int fileNameLen;
    int dataLen;
 
    connect(sock,(SOCKADDR*)&servAddr,sizeof(servAddr));
 
    char cmd[20] = {0};
    printf("> ");
    scanf("%s", cmd);
    send(sock, cmd, sizeof(cmd), 0);
 
    ZeroMemory(data, sizeof(data));
    while((dataLen = recv(sock,data,20,0)) != 0){
        printf("%s", data);
        ZeroMemory(data, sizeof(data));
    }
    closesocket(sock);
    WSACleanup();
    return 0;
}