[C] Portscan

zu verlinkende lib: ws2_32.lib
unter Dev-Cpp: libws2_32.a

#include <windows.h>
#include <winsock2.h>
#include <stdio.h>
int start()
{
    WSADATA wsa;
    return WSAStartup(MAKEWORD(2,0),&wsa);
}
int main(int argc,char *argv[])
{
    if(argc!=2)
    {
               printf("Benutzung: %s <ip>\n",argv[1]);
               return 1;
    }
    start();
    int i;
    int count=0;;
    SOCKADDR_IN addr;
    SOCKET s;
    long rc;
    for(i=1;i<65535;i++)
    {
              FILE *fp;
              fp = fopen("log.txt" , "a");
              if(i==1)
              {
                      fprintf(fp,"PORTSCAN ON %s\n",argv[1]);
              }
              s = socket(AF_INET,SOCK_STREAM,0);
              if(s == SOCKET_ERROR)
              {
                              printf("ERROR: %d\n",s);
                              return 1;
              }
              addr.sin_addr.s_addr = inet_addr(argv[1]);
              addr.sin_port = htons(i);
              addr.sin_family = AF_INET;
              rc = connect(s,(SOCKADDR*)&addr,sizeof(SOCKADDR_IN));
              if(rc!=-1)
              {
                        printf("OPEN PORT: %d\n",i);
                        fprintf(fp,"OPEN PORT: %d\n",i);
                        count++;
              }
              close(s);
              fclose(fp);
    }
    FILE *fp;
    fp = fopen("log.txt" , "a");
    fprintf(fp,"\n%d PORTS OPEN ON %s\n",count,argv[1]);
    fclose(fp);
    return 0;
}