001  #include <winsock2.h>
002  #include <stdio.h>
003  
004  #define MAX_PACKETLEN 1024
005  #define PORT 3500
006  
007  int main()
008  {
009    WSADATA wsaData;
010    SOCKET listen_s, client_s;
011    struct sockaddr_in server_addr, client_addr;
012    char szReceiveBuffer[MAX_PACKETLEN];
013    int readn, writen;
014    int len;
015  
016    if(WSAStartup(MAKEWORD(2,2), &wsaData) != 0)
017    {
018      return 1;
019    }
020    listen_s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
021    if(listen_s == INVALID_SOCKET)
022    {
023      return 1;
024    }
025   
026    ZeroMemory(&server_addr, sizeof(struct sockaddr_in));
027  
028    server_addr.sin_family = PF_INET;
029    server_addr.sin_port = htons(PORT);
030    server_addr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
031  
032    if(bind(listen_s, (struct sockaddr *)&server_addr, sizeof(struct sockaddr_in)) == SOCKET_ERROR)
033    {
034      return 0;
035    }
036    if(SOCKET_ERROR == listen(listen_s, 5) == SOCKET_ERROR)
037    {
038      return 0;
039    }
040  
041  
042    while(1)
043    {
044      ZeroMemory(&client_addr, sizeof(struct sockaddr_in));
045      len = sizeof(struct sockaddr_in);
046      client_s = accept(listen_s, (struct sockaddr *)&client_addr, &len);
047      readn = recv(client_s, szReceiveBuffer, MAX_PACKETLEN, 0);
048      if(readn > 0)
049      {
050        writen = send(client_s, szReceiveBuffer, readn, 0); 
051      }
052      closesocket(client_s);
053    }
054    closesocket(listen_s);
055    WSACleanup();
056    return 0;
057  }
058