fuzz_ip6.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <time.h>
#include <pcap.h>
#include "thc-ipv6.h"

/*
 * Fuzzing data types:
 *  F = flags = 1 byte = 8 bits | flags | 8 ; 256 
 *  B = byte = 1 byte | 0 1 254 255 xor XOR | 6 ; 256
 *  X = byte = 1 byte | all values from 0 to 255
 *  W = word = 2 bytes | 0,1,254,255^2 xor XOR | 18 ; 65536
 *  D = double word = 4 bytes | {0,1,254,255}^4 xor XOR | 258 ; 4294967295
 *  . = byte = ignore, jump over
 *
 */

char fuzztype_ether[] = "..............";
char fuzztype_ip6[] = "XF..WXBXX..............XX..............";
char fuzztype_ip6no[] = "........................................";
char fuzztype_icmp6[] = "XX..";
char fuzztype_icmp6no[] = "....";
char fuzztype_icmp6ping[] = "";
char fuzztype_icmp6ra[] = "........XXWWWXXXX........XX.............XXXX....XXXXXBB..XX.............XXXBB....XX.............XXXBB....X...X....XX.....X......XXXXXXXXX";
char fuzztype_icmp6ns[] = "XX..XX............XXXX";
char fuzztype_icmp6na[] = "FFFFXX............XXXX";
char fuzztype_icmp6nq[] = "FXFX........XX............XX";
char fuzztype_icmp6mld[] = "WWXXXX............XX";
char fuzztype_icmp6mld2rep[] = "WFFXFFF................................................XFFF................................................XFFF................................................";
char fuzztype_icmp6mld2que[] = "WWXXXX............XXFWFF";
char fuzztype_tcp[] = "WWWWWWXXWWWXXWXXXXXXWWWWXX"; 

unsigned char flags[] = { 0, 1, 2, 4, 8, 16, 32, 64, 128, 254, 255 };   // 11
unsigned char bytes[] = { 0, 1, 254, 255 };     // 4
unsigned short int words[] = { 0x0000, 0x0001, 0x00fe, 0x00ff, 0x0100, 0x0101,
  0x01fe, 0x01ff, 0xfe00, 0xfe01, 0xfefe, 0xfeff, 0xff00, 0xff01, 0xfffe,
  0xffff
};                              // 16
unsigned int xors[] = { 0, 0xffffffff };        // 2
unsigned char extends[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
  15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
  34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
  53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,
  72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,
  91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
  108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122,
  123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137,
  138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152,
  153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167,
  168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182,
  183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197,
  198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212,
  213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227,
  228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242,
  243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255
};                              // 256
unsigned int dwords[] = { 0x00000000, 0x00000001, 0x000000fe, 0x000000ff,
  0x00000100, 0x00000101, 0x000001fe, 0x000001ff,
  0x0000fe00, 0x0000fe01, 0x0000fefe, 0x0000feff,
  0x0000ff00, 0x0000ff01, 0x0000fffe, 0x0000ffff,
  0x00010000, 0x00010001, 0x000100fe, 0x000100ff,
  0x00010100, 0x00010101, 0x000101fe, 0x000101ff,
  0x0001fe00, 0x0001fe01, 0x0001fefe, 0x0001feff,
  0x0001ff00, 0x0001ff01, 0x0001fffe, 0x0001ffff,
  0x00fe0000, 0x00fe0001, 0x00fe00fe, 0x00fe00ff,
  0x00fe0100, 0x00fe0101, 0x00fe01fe, 0x00fe01ff,
  0x00fefe00, 0x00fefe01, 0x00fefefe, 0x00fefeff,
  0x00feff00, 0x00feff01, 0x00fefffe, 0x00feffff,
  0x00ff0000, 0x00ff0001, 0x00ff00fe, 0x00ff00ff,
  0x00ff0100, 0x00ff0101, 0x00ff01fe, 0x00ff01ff,
  0x00fffe00, 0x00fffe01, 0x00fffefe, 0x00fffeff,
  0x00ffff00, 0x00ffff01, 0x00fffffe, 0x00ffffff,
  0x01000000, 0x01000001, 0x010000fe, 0x010000ff,
  0x01000100, 0x01000101, 0x010001fe, 0x010001ff,
  0x0100fe00, 0x0100fe01, 0x0100fefe, 0x0100feff,
  0x0100ff00, 0x0100ff01, 0x0100fffe, 0x0100ffff,
  0x01010000, 0x01010001, 0x010100fe, 0x010100ff,
  0x01010100, 0x01010101, 0x010101fe, 0x010101ff,
  0x0101fe00, 0x0101fe01, 0x0101fefe, 0x0101feff,
  0x0101ff00, 0x0101ff01, 0x0101fffe, 0x0101ffff,
  0x01fe0000, 0x01fe0001, 0x01fe00fe, 0x01fe00ff,
  0x01fe0100, 0x01fe0101, 0x01fe01fe, 0x01fe01ff,
  0x01fefe00, 0x01fefe01, 0x01fefefe, 0x01fefeff,
  0x01feff00, 0x01feff01, 0x01fefffe, 0x01feffff,
  0x01ff0000, 0x01ff0001, 0x01ff00fe, 0x01ff00ff,
  0x01ff0100, 0x01ff0101, 0x01ff01fe, 0x01ff01ff,
  0x01fffe00, 0x01fffe01, 0x01fffefe, 0x01fffeff,
  0x01ffff00, 0x01ffff01, 0x01fffffe, 0x01ffffff,
  0xfe000000, 0xfe000001, 0xfe0000fe, 0xfe0000ff,
  0xfe000100, 0xfe000101, 0xfe0001fe, 0xfe0001ff,
  0xfe00fe00, 0xfe00fe01, 0xfe00fefe, 0xfe00feff,
  0xfe00ff00, 0xfe00ff01, 0xfe00fffe, 0xfe00ffff,
  0xfe010000, 0xfe010001, 0xfe0100fe, 0xfe0100ff,
  0xfe010100, 0xfe010101, 0xfe0101fe, 0xfe0101ff,
  0xfe01fe00, 0xfe01fe01, 0xfe01fefe, 0xfe01feff,
  0xfe01ff00, 0xfe01ff01, 0xfe01fffe, 0xfe01ffff,
  0xfefe0000, 0xfefe0001, 0xfefe00fe, 0xfefe00ff,
  0xfefe0100, 0xfefe0101, 0xfefe01fe, 0xfefe01ff,
  0xfefefe00, 0xfefefe01, 0xfefefefe, 0xfefefeff,
  0xfefeff00, 0xfefeff01, 0xfefefffe, 0xfefeffff,
  0xfeff0000, 0xfeff0001, 0xfeff00fe, 0xfeff00ff,
  0xfeff0100, 0xfeff0101, 0xfeff01fe, 0xfeff01ff,
  0xfefffe00, 0xfefffe01, 0xfefffefe, 0xfefffeff,
  0xfeffff00, 0xfeffff01, 0xfefffffe, 0xfeffffff,
  0xff000000, 0xff000001, 0xff0000fe, 0xff0000ff,
  0xff000100, 0xff000101, 0xff0001fe, 0xff0001ff,
  0xff00fe00, 0xff00fe01, 0xff00fefe, 0xff00feff,
  0xff00ff00, 0xff00ff01, 0xff00fffe, 0xff00ffff,
  0xff010000, 0xff010001, 0xff0100fe, 0xff0100ff,
  0xff010100, 0xff010101, 0xff0101fe, 0xff0101ff,
  0xff01fe00, 0xff01fe01, 0xff01fefe, 0xff01feff,
  0xff01ff00, 0xff01ff01, 0xff01fffe, 0xff01ffff,
  0xfffe0000, 0xfffe0001, 0xfffe00fe, 0xfffe00ff,
  0xfffe0100, 0xfffe0101, 0xfffe01fe, 0xfffe01ff,
  0xfffefe00, 0xfffefe01, 0xfffefefe, 0xfffefeff,
  0xfffeff00, 0xfffeff01, 0xfffefffe, 0xfffeffff,
  0xffff0000, 0xffff0001, 0xffff00fe, 0xffff00ff,
  0xffff0100, 0xffff0101, 0xffff01fe, 0xffff01ff,
  0xfffffe00, 0xfffffe01, 0xfffffefe, 0xfffffeff,
  0xffffff00, 0xffffff01, 0xfffffffe, 0xffffffff
};                              // 256

#define COUNT_FLAG     11
#define COUNT_BYTE      4
#define COUNT_WORD     16
#define COUNT_XOR       2
#define COUNT_EXTEND  256

#define NEVER 2000000000
#define TEST_MAX (NEVER - 1)

#define DO_NONE      0
#define DO_PING      1
#define DO_NEIGHSOL  2
#define DO_NEIGHADV  3
#define DO_RA        4
#define DO_NODEQUERY 5
#define DO_TCP       6
#define DO_MLD_REP  131
#define DO_MLD_DONE  132
#define DO_MLD_QUERY  130
#define DO_MLD2_QUERY  256
#define DO_MLD2_REPORT 143

int port = -1;

void help(char *prg) {
  printf("%s %s (c) 2016 by %s %s\n\n", prg, VERSION, AUTHOR, RESOURCE);
  printf("Syntax: %s [-x] [-t number | -T number] [-p number] [-IFSDHRJ] [-X|-1|-2|-3|-4|-5|-6|-7|-8|-9|-0 port] interface unicast-or-multicast-address [address-in-data-pkt]\n\n", prg);
  printf("Fuzzes an icmp6 packet\n");
  printf("Options:\n");
  printf(" -X         do not add any ICMP/TCP header (transport layer)\n");
  printf(" -1         fuzz ICMP6 echo request (default)\n");
  printf(" -2         fuzz ICMP6 neighbor solicitation\n");
  printf(" -3         fuzz ICMP6 neighbor advertisement\n");
  printf(" -4         fuzz ICMP6 router advertisement\n");
  printf(" -5         fuzz multicast listener report packet\n");
  printf(" -6         fuzz multicast listener done packet\n");
  printf(" -7         fuzz multicast listener query packet\n");
  printf(" -8         fuzz multicast listener v2 report packet\n");
  printf(" -9         fuzz multicast listener v2 query packet\n");
  printf(" -0         fuzz node query packet\n");
  printf(" -s port    fuzz TCP-SYN packet against port\n");       
  printf(" -x         tries all 256 values for flag and byte types\n");
  printf(" -t number  continue from test no. number\n");
  printf(" -T number  only performs test no. number\n");
  printf(" -p number  perform an alive check every number of tests (default: none)\n");
  printf(" -a         do not perform initial and final alive test\n");
  printf(" -n number  how many times to send each packet (default: 1)\n");
  printf(" -I         fuzz the IP header too\n");
  printf(" -F         add one-shot fragmentation, and fuzz it too (for 1)\n");
  printf(" -S         add source-routing, and fuzz it too (for 1)\n");
  printf(" -D         add destination header, and fuzz it too (for 1)\n");
  printf(" -H         add hop-by-hop header, and fuzz it too (for 1 and 5-9)\n");
  printf(" -R         add router alert header, and fuzz it too (for 5-9 and all)\n");
  printf(" -J         add jumbo packet header, and fuzz it too (for 1)\n");
//  printf("Use -r to use raw mode.\n");
  printf("You can only define one of -0 ... -9 and -s, defaults to -1.\n");
  printf("Returns -1 on error, 0 on tests done and targt alive or 1 on target crash.\n");
  exit(-1);
}

void ignoreit(u_char *foo, const struct pcap_pkthdr *header, const unsigned char *data) {
  return;
}

int check_alive(pcap_t * p, char *interface, unsigned char *srcmac, unsigned char *dstmac, unsigned char *src, unsigned char *dst) {
  int ret = -2;
  time_t t;

  while (thc_pcap_check(p, (char *) ignoreit, NULL) > 0);
  thc_ping26(interface, srcmac, dstmac, src, dst, 16, 1);
  t = time(NULL);
  while (ret < 0) {
    if (thc_pcap_check(p, (char *) ignoreit, NULL) > 0)
      ret = 1;
    if (time(NULL) > t + 1 && ret == -2) {
      thc_ping26(interface, srcmac, dstmac, src, dst, 16, 1);
      ret = -1;
    }
    if (time(NULL) > t + 4 && ret < 0)
      ret = 0;
  }

  return ret > 0 ? 1 : 0;
}

int main(int argc, char *argv[]) {
  unsigned char *pkt = NULL, *pkt_bak, *mcast6, *someaddr6 = NULL;
  unsigned char *dst6, *src6 = NULL, *mac = NULL, *routers[2], string[64] = "ip6 and dst ";
  int test_start = 0, fragment = 0, alert = 0, sroute = 0;
  int do_type = DO_PING, do_alive = 1, hopbyhop = 0, destination = 0, jumbo = 0;
  int pkt_len = 0, offset = 0, test_current = 0, i, j, k, do_fuzz = 1, test_ptr = 0;
  int test_end = TEST_MAX, ping = NEVER, frag_offset = 0, header = 0, no_send = 1;
  int test_pos = 0, test_cnt = 0, do_it, extend = 0, mtu = 1500, size = 64, wait = 0, off2 = 14;
  char *interface, fuzzbuf[256], *srcmac, *dns, *route6, *real_dst6 = NULL;
  unsigned char buf[256], buf2[100], buf3[16];
  unsigned short int *sip;
  pcap_t *p;
  thc_ipv6_hdr *hdr;

  if (argc < 3 || strncmp(argv[1], "-h", 2) == 0)
    help(argv[0]);

  while ((i = getopt(argc, argv, "s:0123456789Xxt:T:p:FSDHRIJan:")) >= 0) {
    switch (i) {
    case 's':
      do_type = DO_TCP;
      port = atoi(optarg);
      break;
    case '0':
      do_type = DO_NODEQUERY;
      break;
    case '1':
      do_type = DO_PING;
      break;
    case '2':
      do_type = DO_NEIGHSOL;
      break;
    case '3':
      do_type = DO_NEIGHADV;
      break;
    case '4':
      do_type = DO_RA;
      break;
    case '5':
      do_type = DO_MLD_REP;
      break;
    case '6':
      do_type = DO_MLD_DONE;
      break;
    case '7':
      do_type = DO_MLD_QUERY;
      wait = 0xff0000;
      break;
    case '8':
      do_type = DO_MLD2_REPORT;
      break;
    case '9':
      do_type = DO_MLD2_QUERY;
      wait = 0xff0000;
      break;
    case 'X':
      do_type = DO_NONE;
      break;
    case 't':
      test_start = atoi(optarg);
      break;
    case 'T':
      test_end = test_start = atoi(optarg);
      break;
    case 'p':
      ping = atoi(optarg);
      break;
    case 'a':
      do_alive = 0;
      break;
    case 'S':
      sroute = 1;
      break;
    case 'n':
      no_send = atoi(optarg);
      break;
    case 'F':
      fragment = 1;
      break;
    case 'R':
      alert = 1;
      break;
    case 'D':
      destination = 1;
      break;
    case 'H':
      hopbyhop = 1;
      break;
    case 'J':
      jumbo = 1;
      break;
    case 'I':
      header = 1;
      break;
    case 'x':
      extend = 1;
      break;
    }
  }
  if (argc - optind < 2) {
    fprintf(stderr, "ERROR: not enough options, interface and target address are required!\n");
    exit(-1);
  }
  interface = argv[optind];
  if ((srcmac = thc_get_own_mac(interface)) == NULL) {
    fprintf(stderr, "ERROR: %s is not a valid interface which has a MAC, use raw mode?\n", interface);
    exit(-1);
  }
  if (no_send < 1) {
    fprintf(stderr, "ERROR: -n number must be between one and 2 billion\n");
    exit(-1);
  }
  if (do_hdr_size) {
    test_pos -= do_hdr_size;
    offset -= do_hdr_size;
    off2 = do_hdr_size;
  }
  if (do_type != DO_PING && do_type != DO_TCP && do_type != DO_NONE) {
    if ((mcast6 = thc_resolve6(argv[optind + 1])) == NULL) {
      fprintf(stderr, "Error: %s does not resolve to a valid IPv6 address\n", argv[optind + 1]);
      exit(-1);
    }

    if (do_type == DO_NEIGHSOL) {
      dst6 = thc_resolve6("ff02::0001:ff00:0000");
      memcpy(dst6 + 13, mcast6 + 13, 3);
    } else
      dst6 = thc_resolve6("ff02::1");
  } else {
    dst6 = thc_resolve6(argv[optind + 1]);
  }
  if (argv[optind + 1] != NULL)
    if ((real_dst6 = thc_resolve6(argv[optind + 1])) == NULL) {
      fprintf(stderr, "Error: %s does not resolve to a valid IPv6 address\n", argv[optind + 1]);
      exit(-1);
    }


  if (interface == NULL || argv[optind + 1] == NULL) {
    printf("Error: interface and target-ipv6-address are mandatory command line options\n");
    exit(-1);
  }
  if (ping < 1 || test_end < test_start) {
    printf("don't fuck up the command line options!\n");
    exit(-1);
  }
  if (argv[optind + 2] != NULL)
    someaddr6 = thc_resolve6(argv[optind + 2]);
  if (argc - optind > 3) {
    printf("Error: too many command line options\n");
    exit(-1);
  }
  if ((mac = thc_get_mac(interface, src6, dst6)) == NULL) {
    fprintf(stderr, "ERROR: Can not resolve mac address for %s\n", argv[2]);
    exit(-1);
  }

  if (do_type == DO_PING || do_type == DO_TCP || do_type == DO_NONE)
    src6 = thc_get_own_ipv6(interface, dst6, PREFER_GLOBAL);
  else
    src6 = thc_get_own_ipv6(interface, dst6, PREFER_LINK);
  if (src6 == NULL) {
    fprintf(stderr, "Error: no IPv6 address configured on interface %s\n", interface);
    exit(-1);
  }
  strcat(string, thc_ipv62notation(src6));
  if (sroute) {
    if (someaddr6 != NULL)
      routers[0] = someaddr6;
    else
      routers[0] = dst6;
    routers[1] = NULL;
  }
  setvbuf(stdout, NULL, _IONBF, 0);
  memset(buf, 0, sizeof(buf));
  memset(buf2, 0, sizeof(buf2));
  dns = thc_resolve6("ff02::fb");
  route6 = thc_resolve6("2a01::");

  if ((p = thc_pcap_init(interface, string)) == NULL) {
    fprintf(stderr, "Error: could not capture on interface %s with string %s\n", interface, string);
    exit(-1);
  }
  if (real_dst6 != NULL && real_dst6[0] == 0xff)
    do_alive = 0;
  // ping before to check if it works
  if (do_alive)
    if (check_alive(p, interface, srcmac, mac, src6, real_dst6) == 0) {
      fprintf(stderr, "Error: target %s is not alive via direct ping6!\n", argv[optind + 1]);
      exit(-1);
    }
  // generate basic packet
  strcpy(fuzzbuf, fuzztype_ether);
  if ((pkt = thc_create_ipv6_extended(interface, PREFER_GLOBAL, &pkt_len, src6, dst6, 0, 0, 0, 0, 0)) == NULL)
    return -1;
  if (header)
    strcat(fuzzbuf, fuzztype_ip6);
  else
    strcat(fuzzbuf, fuzztype_ip6no);

  if (alert || hopbyhop || jumbo) {
    memset(buf2, 0, sizeof(buf2));
    i = 0;
    
    strcat(fuzzbuf, "XX"); // first two bytes of EH

    if (alert) {
      buf2[i++] = 5;
      buf2[i++] = 2;
      i += 2;
      strcat(fuzzbuf, ".FW");
    }

    if (jumbo) {
      buf2[i++] = 0xc2;
      buf2[i++] = 4;
      buf2[i++] = 'J';          // lookup code
      buf2[i++] = 'J';
      buf2[i++] = 'J';
      buf2[i++] = 'J';
      strcat(fuzzbuf, ".FWW");
    }

    if (hopbyhop) {
      memset(buf3, 0, sizeof(buf3));
      buf3[0] = 'X';
      buf3[1] = '.';
      for (j = 0; j < 10; j++) {
        buf2[i++] = 1;          // PadN, length
        buf2[i++] = j;
        if (j > 0) {
          memset(buf2 + i, 0xaa, j);
          buf3[2 + j] = '.';
          i += j;
        }
        strcat(fuzzbuf, buf3);  // always: X..... for every new option
      }
    }
    
    j = 8 - ( ( i + 2 ) % 8 );
    if (j > 0 && j < 8) {
      for (k = 0; k < j; k++)
        strcat(fuzzbuf, "."); // fill because of padding
    }

    if (thc_add_hdr_hopbyhop(pkt, &pkt_len, buf2, i) < 0)
      return -1;

    i += 2;
    if (i % 8 > 0)
      i = ((i / 8) + 1) * 8;

    offset += i;
  }

  if (sroute) {
    if (thc_add_hdr_route(pkt, &pkt_len, routers, 1) < 0)
      return -1;
    else {
      strcat(fuzzbuf, "FFFFBBBB................");
      offset += 24;
    }
  }

  if (fragment) {
    frag_offset = offset;
    if (thc_add_hdr_fragment(pkt, &pkt_len, 0, 0, 0) < 0)
      return -1;
    else {
      strcat(fuzzbuf, "FFWW..");
      offset += 8;
    }
  }

  if (destination) {
    memset(buf2, 0, sizeof(buf2));
    memset(buf3, 0, sizeof(buf3));
    strcat(fuzzbuf, "XX"); // first two bytes of EH
    buf3[0] = 'X';
    buf3[1] = '.';
    i = 0;
    for (j = 0; j < 10; j++) {
      buf2[i++] = 1;            // PadN, length
      buf2[i++] = j;
      if (j > 0) {
        memset(buf2 + i, 0xaa, j);
        buf3[2 + j] = '.';
        i += j;
      }
      strcat(fuzzbuf, buf3);    // always: X... for every new option
    }

    j = 8 - ( ( i + 2 ) % 8 );
    if (j > 0 && j < 8) {
      for (k = 0; k < j; k++)
        strcat(fuzzbuf, "."); // fill because of padding
    }

    if (thc_add_hdr_dst(pkt, &pkt_len, buf2, i) < 0)
      return -1;

    i += 2;
    if (i % 8 > 0)
      i = ((i / 8) + 1) * 8;

    offset += i;
  }

  memset(buf, 0, sizeof(buf));
//  if (header)
    strcat(fuzzbuf, fuzztype_icmp6);
//  else
//    strcat(fuzzbuf, fuzztype_icmp6no);
  switch (do_type) {
  case DO_TCP:
    // tcp options
    buf[0] = 2; // max segment size
    buf[1] = 4;
    buf[2] = 255;
    buf[3] = 255;
    buf[4] = 3; // windows size
    buf[5] = 3;
    buf[6] = 62;
    buf[7] = 1; // padding
    buf[8] = 8; // timestamp
    buf[9] = 10;
    buf[10] = time(NULL) / 16777216;
    buf[11] = ((time(NULL) / 65536) % 256);
    buf[12] = ((time(NULL) / 256) % 256);
    buf[13] = time(NULL) % 256;
    // 4 bytes ack tstamp 00000000
    // rest is padding (2 bytes)
    if (thc_add_tcp(pkt, &pkt_len, 65532, port, test_current, 0, TCP_SYN, 5760, 0, (unsigned char *) buf, 20, (unsigned char *) buf, 20) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_tcp);
    break;

  case DO_PING:
    if (thc_add_icmp6(pkt, &pkt_len, ICMP6_PINGREQUEST, 0, test_current, (unsigned char *) &buf, 16, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6ping);
    break;
    
  case DO_NONE:
    // empty
    break;

  case DO_NEIGHSOL:
    if (someaddr6 != NULL)
      memcpy(buf, someaddr6, 16);
    else
      memcpy(buf, mcast6, 16);
    buf[16] = 1;
    buf[17] = 1;
    memcpy(buf + 18, srcmac, 6);
    if (thc_add_icmp6(pkt, &pkt_len, ICMP6_NEIGHBORSOL, 0, 0, (unsigned char *) &buf, 24, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6ns);
    break;

  case DO_NEIGHADV:
    if (someaddr6 != NULL)
      memcpy(buf, someaddr6, 16);
    else
      memcpy(buf, src6, 16);
    buf[16] = 2;
    buf[17] = 1;
    memcpy(buf + 18, srcmac, 6);
    if (thc_add_icmp6(pkt, &pkt_len, ICMP6_NEIGHBORADV, 0, 0xe0000000, (unsigned char *) &buf, 24, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6na);
    break;
    
  case DO_NODEQUERY:
    memcpy(buf + 8, real_dst6, 16);
    if (thc_add_icmp6(pkt, &pkt_len, ICMP6_NODEQUERY, 0, 0x0003003e, (unsigned char *) &buf, 24, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6nq);
    break;    

  case DO_RA:
    //  buf[3] = 250; // 0-3: reachable timer
    buf[6] = 4;                 // 4-7: retrans timer
    // option mtu
    buf[8] = 5;
    buf[9] = 1;
    buf[12] = mtu / 16777216;

    buf[14] = (mtu % 65536) / 256;
    buf[15] = mtu % 256;
    // option prefix
    buf[16] = 3;
    buf[17] = 4;
    buf[18] = size;             // prefix length
    buf[19] = 128 + 64;
    memset(&buf[20], 17, 4);
    memset(&buf[24], 4, 4);
    if (someaddr6 != NULL)
      memcpy(&buf[32], someaddr6, 16);
    else
      memcpy(&buf[32], route6, 16);

    i = 48;
    // mac address option
    buf[i++] = 1;
    buf[i++] = 1;
    memcpy(buf + i, srcmac, 6);
    i += 6; // = 8 == 56

    // default route routing option
    buf[i++] = 0x18;            // routing entry option type
    buf[i++] = 0x03;            // length 3 == 24 bytes
    buf[i++] = 64;            // prefix length /64
    buf[i++] = 0x08;            // priority, highest of course
    i += 2;                     // 52-53 unknown
    buf[i++] = 0x11;            // lifetime, word
    buf[i++] = 0x11;            // lifetime, word
    buf[i++] = 0x20;
    buf[i++] = 4;               // 56-71 address, 2004:: for default
    i += 14; // = 24 == 70               

    // dns option
    buf[i++] = 0x19;            // dns option type
    buf[i++] = 0x03;            // length
    i += 2;                     // 74-75 reserved
    memset(buf + i, 1, 4);      // validity time
    i += 4;
    if (someaddr6 != NULL)
      memcpy(buf + i, someaddr6, 16);   // dns server
    else
      memcpy(buf + i, dns, 16); // dns server
    i += 16; // = 24 == 94

    // seachlist option
    buf[i++] = 31;
    buf[i++] = 4;
    i += 2;
    memset(buf + i, 1, 4);      // validity time
    i += 4;
    buf[i++] = 3;
    memcpy(buf + i, "foo", 3);
    i += 3;
    buf[i++] = 4;
    memcpy(buf + i, "corp", 4);
    i += 5; // + null byte
    buf[i++] = 5;
    memcpy(buf + i, "local", 5);
    i += 5;
    buf[i++] = 6;
    memcpy(buf + i, "domain", 6);
    i += 7; // + null byte
    // = 32 == 126
    
    // flag extension option
    buf[i++] = 26;
    buf[i++] = 1;
    buf[i++] = 0x08;
    i += 5;

    if (thc_add_icmp6(pkt, &pkt_len, ICMP6_ROUTERADV, 0, 0xff080800, buf, i, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6ra);
    break;

  case DO_MLD_QUERY:
  case DO_MLD_DONE:
  case DO_MLD_REP:
    buf[0] = 0xff;
    buf[1] = 0x02;
    buf[15] = 0x05;
    if (someaddr6 != NULL)
      memcpy(buf, someaddr6, 16);
    if (thc_add_icmp6(pkt, &pkt_len, do_type, 0, wait, buf, 16, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6mld);
    break;
  case DO_MLD2_QUERY:
    buf[0] = 0xff;
    buf[1] = 0x02;
    buf[15] = 0x05;
    if (someaddr6 != NULL)
      memcpy(buf, someaddr6, 16);
    buf[16] = 7;
    buf[17] = 120;
    buf[19] = 3;
    memcpy(buf + 20, dst6, 16);
    memcpy(buf + 36, buf, 16);
    if (thc_add_icmp6(pkt, &pkt_len, DO_MLD_QUERY, 0, wait, buf, 68, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6mld2que);
    break;
  case DO_MLD2_REPORT:
    for (i = 0; i < 3; i++) {
      buf[0 + 68 * i] = 1 + i * 2 - i / 2;      //include new++, generates 1, 3 and 4
      buf[3 + 68 * i] = 3;      //3 sources
      buf[4 + 68 * i] = 0xff;
      buf[5 + 68 * i] = 0x02;
      buf[18 + 68 * i] = 0x82 + i % 256;
      buf[19 + 68 * i] = 0xff;
      memcpy(buf + 20 + 68 * i, src6, 16);
      buf[36 + 68 * i] = 0xfe;
      buf[37 + 68 * i] = 0x80;
      buf[46 + 68 * i] = 0xf0;
      if (someaddr6 != NULL)
        memcpy(buf + 52 + 68 * i, someaddr6, 16);
    }

    if (thc_add_icmp6(pkt, &pkt_len, do_type, 0, 3, buf, 208, 0) < 0)
      return -1;
    strcat(fuzzbuf, fuzztype_icmp6mld2rep);
    break;

  default:
    fprintf(stderr, "ERROR: Mode not implemented yet!\n");
    exit(-1);
  }

  if (thc_generate_pkt(interface, srcmac, mac, pkt, &pkt_len) < 0)
    return -1;
  hdr = (thc_ipv6_hdr *) pkt;

  if (jumbo) {
    i = 0;
    j = 1;
    while (i < hdr->pkt_len + 4 && j) {
      if (hdr->pkt[i] == 'J')
        if (memcmp(&hdr->pkt[i], "JJJJ", 4) == 0)
          j = 0;
      i++;
    }
    if (j) {
      fprintf(stderr, "ERROR: fuckup, cant find my own marker?!\n");
      exit(-1);
    } else
      i--;
    hdr->pkt[i] = 0;
    hdr->pkt[i + 1] = 0;
    hdr->pkt[i + 2] = hdr->pkt[4 + off2];
    hdr->pkt[i + 3] = hdr->pkt[5 + off2];
    hdr->pkt[4 + off2] = 0;
    hdr->pkt[5 + off2] = 0;
  }

  if (extend)
    for (i = 0; i < strlen(fuzzbuf); i++)
      if (fuzzbuf[i] == 'B' || fuzzbuf[i] == 'F')
        fuzzbuf[i] = 'X';

  // backup of generated packet
  pkt_bak = malloc(hdr->pkt_len);
  memcpy(pkt_bak, hdr->pkt, hdr->pkt_len);

  printf("Fuzzing packet, starting at fuzz case %d, ending at fuzz case %d, every packet sent denoted by a dot:\n", test_start, test_end);
//printf("buf(%d): %s\n", strlen(fuzzbuf), fuzzbuf);
  while (do_fuzz) {
    if (test_cnt == 0)
      while (fuzzbuf[test_ptr] == '.') {
        test_ptr++;
        test_pos++;
      }

    if (fuzzbuf[test_ptr] == 0)
      do_fuzz = 0;

    test_cnt++;
    do_it = 1;

//printf("[%s] pos[%d]=%c -> %d | pkt[%d] | %d (%d=>%d)| ", /*fuzzbuf*/"", test_ptr, fuzzbuf[test_ptr], test_cnt, test_pos, test_current, test_start, test_end);
    switch (fuzzbuf[test_ptr]) {
    case 0:
      break;
    case 'X':
      if (test_cnt <= COUNT_EXTEND) {
        if (pkt_bak[test_pos] != extends[test_cnt - 1])
          hdr->pkt[test_pos] = extends[test_cnt - 1];
        else
          do_it = 0;
      } else {
        test_cnt = 0;
        test_ptr++;
        test_pos++;
      }
      break;
    case 'B':
      if (test_cnt <= COUNT_BYTE) {
        if (pkt_bak[test_pos] != bytes[test_cnt - 1])
          hdr->pkt[test_pos] = bytes[test_cnt - 1];
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_BYTE && do_it) {
          if (bytes[i] == pkt_bak[test_pos])
            do_it = 0;
          i++;
        }
        if (do_it)
          hdr->pkt[test_pos] = hdr->pkt[test_pos] ^ xors[test_cnt - COUNT_BYTE - 1];
      }
      if (test_cnt == COUNT_BYTE + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos++;
      }
      break;
    case 'F':
      if (test_cnt <= COUNT_FLAG) {
        if (pkt_bak[test_pos] != flags[test_cnt - 1])
          hdr->pkt[test_pos] = flags[test_cnt - 1];
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_FLAG && do_it) {
          if (bytes[i] == pkt_bak[test_pos])    // yes, bytes[] is the right one even for flags
            do_it = 0;
          i++;
        }
        if (do_it)
          hdr->pkt[test_pos] = hdr->pkt[test_pos] ^ xors[test_cnt - COUNT_BYTE - 1];
      }
      if (test_cnt == COUNT_FLAG + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos++;
      }
      break;
    case 'W':
      sip = (unsigned short int *) &pkt_bak[test_pos];
      if (test_cnt <= COUNT_WORD) {
        if (*sip != words[test_cnt - 1])
          memcpy((char *) &hdr->pkt[test_pos], (char *) &words[test_cnt - 1] + _TAKE2, 2);
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_WORD && do_it) {
          if (words[i] == *sip)
            do_it = 0;
          i++;
        }
        if (do_it) {
          i = *sip ^ xors[test_cnt - COUNT_WORD - 1];
          sip = (unsigned short int *) &hdr->pkt[test_pos];
          *sip = i % 65536;
        }
      }
      if (test_cnt == COUNT_WORD + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos += 2;
      }
      break;
    default:
      fprintf(stderr, "This character should not be in the fuzz string, shoot the programmer: %c(%d) position %d string %s\n", fuzzbuf[test_ptr], fuzzbuf[test_ptr], test_ptr,
              fuzzbuf);
      exit(-1);
      break;
    }

    if (do_it && do_fuzz) {
      if (test_current >= test_start && test_current <= test_end && do_fuzz) {
        // fill icmp id+seq and unique buffer with test case number
        if (fragment)
          memcpy(hdr->pkt + frag_offset + 58, (char *) &test_current + _TAKE4, 4);
        switch (do_type) {
        case DO_NONE:
          // empty
          break;
        case DO_PING:
          for (i = 0; i < 4 + 1; i++)
            memcpy(hdr->pkt + offset + 58 + i * 4, (char *) &test_current + _TAKE4, 4);
          break;
        case DO_TCP:
          memcpy(hdr->pkt + offset + 58, (char *) &test_current + _TAKE4, 4);
          break;
        case DO_NEIGHSOL:
        case DO_NEIGHADV:
          break;                // do nothing for these
        case DO_NODEQUERY:
          memcpy(hdr->pkt + offset + 66, (char *) &test_current + _TAKE4, 4);
          break;
        case DO_RA:
          memcpy(hdr->pkt + offset + 0x62, (char *) &test_current + _TAKE4, 4);  // prefix update
          memcpy(hdr->pkt + offset + 0x7e, hdr->pkt + offset + 0x5e, 16);       // routing update
          memcpy(hdr->pkt + 8, (char *) &test_current + _TAKE4, 4);    // srcmac update
          memcpy(hdr->pkt + offset + 0x72, (char *) &test_current + _TAKE4, 4);  // srcmac update
          memcpy(hdr->pkt + 0x10 + off2, (char *) &test_current + _TAKE4, 4);       // srcip update
          memcpy(hdr->original_src, hdr->pkt + 8 + off2, 16);      // srcip update for checksum
          break;
        case DO_MLD_QUERY:
        case DO_MLD_DONE:
        case DO_MLD_REP:
        case DO_MLD2_QUERY:
          memcpy(hdr->pkt + offset + 0x4a, (char *) &test_current + _TAKE4, 4);
          break;
        case DO_MLD2_REPORT:   //??? XXX TODO CHECK
          memcpy(hdr->pkt + offset + 0x4d, (char *) &test_current + _TAKE4, 4);
          memcpy(hdr->pkt + offset + 0x4d + 68, (char *) &test_current + _TAKE4, 4);
          memcpy(hdr->pkt + offset + 0x4d + 136, (char *) &test_current + _TAKE4, 4);
          break;
        default:
          fprintf(stderr, "ERROR!!!\n");
          exit(-1);
        }

        // regenerate checksum
        if (do_type != DO_TCP && do_type != DO_NONE) {       // maybe for later non-icmp stuff
          hdr->pkt[offset + 56] = 0;
          hdr->pkt[offset + 57] = 0;
          i = checksum_pseudo_header(hdr->original_src, hdr->final_dst, NXT_ICMP6, &hdr->pkt[offset + 54], hdr->pkt_len - offset - 54);
          hdr->pkt[offset + 56] = i / 256;
          hdr->pkt[offset + 57] = i % 256;
        } else { // TCP
          hdr->pkt[offset + 70] = 0;
          hdr->pkt[offset + 71] = 0;
          i = checksum_pseudo_header(hdr->original_src, hdr->final_dst, NXT_TCP, &hdr->pkt[offset + 54], hdr->pkt_len - offset - 54);
          hdr->pkt[offset + 70] = i / 256;
          hdr->pkt[offset + 71] = i % 256;
        }
        // send packet
        for (k = 0; k < no_send; k++) {
          while(thc_send_pkt(interface, pkt, &pkt_len) < 0)
            usleep(1);
        }
        printf(".");
        usleep(250);
        // if ping, check ping again
        if ((test_current - test_start) % ping == 0 && test_current != 0 && test_start != test_current)
          if (check_alive(p, interface, srcmac, mac, src6, real_dst6) == 0) {
            i = ((((test_current - test_start) / ping) - 1) * ping) + test_start + 1;
            printf("\nResult: target %s crashed during fuzzing, offending test case no. could be %d to %d\n", argv[optind + 1], i < 0 ? 0 : i, test_current);
            exit(1);
          }
      }
//else printf("NOT SENT - NOT IN TEST LIST\n");
      // reset to basic packet
      memcpy(hdr->pkt, pkt_bak, hdr->pkt_len);
      test_current++;
    }
//else printf("NOT SENT!\n");
  }

  printf("\n");
  // ping afterwards to check if it worked
  if (do_alive) {
    if (check_alive(p, interface, srcmac, mac, src6, real_dst6) == 0) {
      printf("Result: target %s is NOT alive via direct ping6 - good work! (position: %d)\n", argv[optind + 1], test_pos);
      exit(1);
    } else
      printf("Result: target %s is still alive via direct ping6, better luck next time.\n", argv[optind + 1]);
  }

  thc_pcap_close(p);
  return 0;
}