dnsdict6.c

/*
 * dnsdict6 is actually based on dnsmap with four changes:
 *   - threaded (way faster)
 *   - bugfixes
 *   - ipv6 support
 *   - simplified options
 *   - srv support
 * have fun!     van Hauser / THC, (c) 2022
 *
 * ** dnsmap - DNS Network Mapper by pagvac
 * ** Copyright (C) 2014 gnucitizen.org
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <resolv.h>
#include "thc-ipv6.h"
#include "dnsdict6.h"  // built-in subdomains list

//#define DEBUG 1
#define FALSE 0
#define TRUE 1
#define MAXSTRSIZE 200
#define DEFAULT_THREADS 8
#define MAX_THREADS 32
#define MAX_UNIQUE 4096
#define MAX_WCARD 8

char               domain[256];
unsigned short int filtIPcount = 0, milliseconds = 10, ipCount = 0, ipCount4;
unsigned short int intIPcount = 0, found = 0, txtResults = FALSE, do4 = 0,
                   do6 = 1, dof = 0, dosrv = 0;
unsigned short int csvResults = FALSE, do_a_delay = FALSE, ucount = 0,
                   ucount4 = 0, ucountsrv = 0, ucountsrvs = 0, wcard = 0,
                   wcard4 = 0;
char wildcardIpStr[MAX_WCARD][INET_ADDRSTRLEN], wildcardIpStr4[MAX_WCARD][16],
    unique[MAX_UNIQUE][INET_ADDRSTRLEN], unique4[MAX_UNIQUE][16];
char **            sub = (char **)sub_medium, *type = "";
char ***           lists;
unsigned short int listptr[MAX_THREADS];

void *help(char *prg) {
  printf("%s %s (c) 2022 by %s %s\n\n", prg, VERSION, AUTHOR, RESOURCE);
  printf(
      "Syntax: %s [-d4] [-s|-m|-l|-x|-u] [-t THREADS] [-D] domain "
      "[dictionary-file]\n\n",
      prg);
  printf(
      "Enumerates a domain for DNS entries, it uses a dictionary file if "
      "supplied\n");
  printf(
      "or a built-in list otherwise. This tool is based on dnsmap by "
      "gnucitizen.org.\n\n");
  printf("Options:\n");
  //  printf(" -6      do NOT dump IPv6 addresses\n");
  printf(" -4      do also dump IPv4 addresses\n");
  printf(
      " -t NO   specify the number of threads to use (default: %d, max: %d).\n",
      DEFAULT_THREADS, MAX_THREADS);
  printf(" -D      dump the selected built-in wordlist, no scanning.\n");
  printf(
      " -d      display IPv6 information on NS and MX DNS domain "
      "information.\n");
  printf(" -e      ignore no NS for domain errors\n");
  printf(" -S      perform SRV service name guessing\n");
  printf(
      " -[smlxu] choose the dictionary size by -s(mall=100), -m(edium=1419) "
      "(DEFAULT)\n");
  printf("           -l(arge=2601), -x(treme=5886) or -u(ber=16724)\n");
  printf("\n");
  exit(-1);
}

// return true if the domain seems valid (NS entry exists)
int verifyDomain(char *dom) {
  unsigned char vbuf[1024];

  if (res_query(dom, ns_c_in, ns_t_ns, vbuf, sizeof(vbuf)) >= 0) return TRUE;

  return FALSE;
}

// return true if domain wildcards are enabled
unsigned short int wildcarDetect(char *dom) {
  char                 s[MAXSTRSIZE] = "";
  unsigned short int   i = 0, j, k, max = 8;
  struct addrinfo      hints, *res, *p;
  void *               addr, *addr4;
  int                  status;
  char                 ipv6str[INET6_ADDRSTRLEN];
  char                 ipv4str[16];
  struct sockaddr_in6 *ipv6, *q;
  struct sockaddr_in * ipv4, *q4;

  memset(&hints, 0, sizeof hints);
  hints.ai_family = dof;  // AF_INET or AF_INET6 to force version
  srand(time(NULL));

  // generate up to random digits subdomain string
  // e.g. 06312580442146732554
  for (i = 0; i < max; ++i)
    s[i] = '0' + (rand() % 10);
  s[max] = 0;
  strcat(s, "0193.");
  strcat(s, dom);
#if DEBUG
  printf("random subdomain for wildcard testing: %s\n", s);
#endif
  // random subdomain resolves, thus wildcards are enabled
  if ((status = getaddrinfo(s, NULL, &hints, &res)) == 0) {
    fprintf(stderr, "Warning: wildcard domain configured\n");
    q = NULL;
    q4 = NULL;
    for (p = res; p != NULL; p = p->ai_next) {
      if (do6 && p->ai_family == AF_INET6) {  // IPv6
        ipv6 = (struct sockaddr_in6 *)p->ai_addr;
        addr = &(ipv6->sin6_addr);
        if (q == NULL || memcmp(&ipv6->sin6_addr, &q->sin6_addr, 16) != 0) {
          q = ipv6;
          if (wcard < MAX_WCARD) {
            memcpy(wildcardIpStr[wcard], addr, 16);
            wcard++;
          }
          inet_ntop(p->ai_family, addr, ipv6str, sizeof ipv6str);
          printf("*.%s => %s\n", dom, ipv6str);
        }
      } else if (do4 && p->ai_family == AF_INET) {
        ipv4 = (struct sockaddr_in *)p->ai_addr;
        addr4 = &(ipv4->sin_addr);
        if (q4 == NULL || memcmp(&ipv4->sin_addr, &q4->sin_addr, 4) != 0) {
          q4 = ipv4;
          if (wcard4 < MAX_WCARD) {
            memcpy(wildcardIpStr4[wcard4], addr4, 4);
            wcard4++;
          }
          inet_ntop(p->ai_family, addr4, ipv4str, sizeof ipv4str);
          printf("*.%s -> %s\n", dom, ipv4str);
        }
      }
    }
    freeaddrinfo(res);
  }

  for (i = 0; i < max; ++i)
    s[i] = 'a' + (rand() % 26);
  s[max] = 'y';
  s[max + 1] = 'c';
  s[max + 2] = 'a';
  s[max + 3] = 'y';
#if DEBUG
  printf("random subdomain for wildcard testing: %s\n", s);
#endif
  // random subdomain resolves, thus wildcards are enabled
  if ((status = getaddrinfo(s, NULL, &hints, &res)) == 0) {
    if (wcard == 0)
      fprintf(stderr, "Warning: wildcard domain configured (2nd test)\n");
    q = NULL;
    q4 = NULL;
    for (p = res; p != NULL; p = p->ai_next) {
      if (do6 && p->ai_family == AF_INET6) {  // IPv6
        ipv6 = (struct sockaddr_in6 *)p->ai_addr;
        addr = &(ipv6->sin6_addr);
        if (q == NULL || memcmp(&ipv6->sin6_addr, &q->sin6_addr, 16) != 0) {
          q = ipv6;
          if (wcard < MAX_WCARD) {
            k = 1;
            if (wcard > 0)
              for (j = 0; j < wcard; j++)
                if (memcmp(wildcardIpStr[j], addr, 16) == 0) k = 0;
            if (k) {
              memcpy(wildcardIpStr[wcard], addr, 16);
              wcard++;
              inet_ntop(p->ai_family, addr, ipv6str, sizeof ipv6str);
              printf("*.%s => %s\n", dom, ipv6str);
            }
          }
        }
      } else if (do4 && p->ai_family == AF_INET) {
        ipv4 = (struct sockaddr_in *)p->ai_addr;
        addr4 = &(ipv4->sin_addr);
        if (q4 == NULL || memcmp(&ipv4->sin_addr, &q4->sin_addr, 4) != 0) {
          q4 = ipv4;
          if (wcard4 < MAX_WCARD) {
            k = 1;
            if (wcard4 > 0)
              for (j = 0; j < wcard4; j++)
                if (memcmp(wildcardIpStr4[j], addr4, 4) == 0) k = 0;
            if (k) {
              memcpy(wildcardIpStr4[wcard4], addr4, 4);
              wcard4++;
              inet_ntop(p->ai_family, addr4, ipv4str, sizeof ipv4str);
              printf("*.%s -> %s\n", dom, ipv4str);
            }
          }
        }
      }
    }
    freeaddrinfo(res);
  }

  if (wcard)
    return TRUE;
  else
    return FALSE;
}

// return number of milliseconds delayed
unsigned short int dodelay(unsigned short int maxmillisecs) {
  unsigned short int n = 0;

  srand(time(NULL));
  n = rand() % maxmillisecs;
  ++n;
  maxmillisecs = n;
#if DEBUG
  printf("sleeping %d milliseconds ...\n", maxmillisecs);
#endif
  usleep(maxmillisecs * 1000);
  return maxmillisecs;
}

// return true if domain is valid, false otherwise
int isValidDomain(char *d) {
  unsigned int i = 0;
  char *       tld;
  size_t       len;

  if (d[strlen(d) - 1] == '.') d[strlen(d) - 1] = 0;
  if (strlen(d) < 4)  // smallest possible domain provided. e.g. a.de
    return FALSE;
  if (!strstr(d, "."))  // target domain must have at least one dot. e.g.
                        // target.va, branch.target.va
    return FALSE;
  if (strlen(d) > 100) return FALSE;
  tld = strstr(d, ".");
  tld = tld + 1;
  while (strstr(tld, ".")) {
    tld = strstr(tld, ".");
    tld = tld + 1;
  }
#if DEBUG
  printf("tld\'s length: %d\n", strlen(tld));
  printf("dom: %s tld: %s\n", d, tld);
#endif
  if ((strlen(tld) < 2) ||
      (strlen(tld) > 6))  // tld must be between 2-6 char. e.g. .museum, .uk
    return FALSE;
  // valid domain can only contain digits, letters, dot (.) and dash symbol (-)
  len = strlen(d);
  for (i = 0; i < len; ++i) {
    if (!(d[i] >= '0' && d[i] <= '9') && !(d[i] >= 'a' && d[i] <= 'z') &&
        !(d[i] >= 'A' && d[i] <= 'Z') && !(d[i] >= '-' && d[i] <= '.'))
      return FALSE;
  }
  return TRUE;
}

void threaded_resolve(char *list[]) {
  int                  i = 0, j, k;
  char                 dom[MAXSTRSIZE] = "", *foo = "", buf[1024];
  void *               addr, *addr4;
  struct addrinfo      hints, *res, *p;
  int                  status, found2;
  char                 ipv6str[INET6_ADDRSTRLEN], ipv4str[16];
  struct sockaddr_in6 *ipv6, *q;
  struct sockaddr_in * ipv4, *q4;

  memset(&hints, 0, sizeof hints);
  hints.ai_family = dof;  // AF_INET or AF_INET6 to force version

  if (type == NULL) type = foo;

  i = 0;
  while (list[i] != NULL && list[i][0] != 0) {
    snprintf(dom, sizeof(dom), "%s.%s", list[i], domain);
#if DEBUG
    printf("brute-forced domain: %s\n", dom);
#endif
    // ipv6 code modded from www.kame.net
    if ((status = getaddrinfo(dom, NULL, &hints, &res)) == 0) {
      q = NULL;
      q4 = NULL;
      found2 = 0;
      for (p = res; p != NULL; p = p->ai_next) {
        if (do6 && p->ai_family == AF_INET6) {  // IPv6
          ipv6 = (struct sockaddr_in6 *)p->ai_addr;
          addr = &(ipv6->sin6_addr);
          // convert the IP to a string and print it:
          if (q == NULL || memcmp(&ipv6->sin6_addr, &q->sin6_addr, 16) != 0) {
            q = ipv6;
            k = 1;
            if (wcard)
              for (j = 0; j < wcard; j++)
                if (memcmp(addr, wildcardIpStr[j], 16) == 0) k = 0;
            if (k) {
              if (found2 == 0) {
                ++found;
                found2 = 1;
              }
              inet_ntop(p->ai_family, addr, ipv6str, sizeof ipv6str);
              sprintf(buf, "%s => %s\n", dom, ipv6str);
              printf("%s", buf);
              ++ipCount;
              if (ucount < MAX_UNIQUE) {
                if (ucount)
                  for (j = 0; j < ucount; j++)
                    if (memcmp(addr, unique[j], 16) == 0) k = 0;
                if (k) {
                  memcpy(unique[ucount], addr, 16);
                  ucount++;
                }
              }
            }
          }
        } else if (do4 && p->ai_family == AF_INET) {
          ipv4 = (struct sockaddr_in *)p->ai_addr;
          addr4 = &(ipv4->sin_addr);
          if (q4 == NULL || memcmp(&ipv4->sin_addr, &q4->sin_addr, 4) != 0) {
            q4 = ipv4;
            k = 1;
            if (wcard4)
              for (j = 0; j < wcard4; j++)
                if (memcmp(wildcardIpStr4[j], addr4, 4) == 0) k = 0;
            if (k) {
              if (found2 == 0) {
                ++found;
                found2 = 1;
              }
              inet_ntop(p->ai_family, addr4, ipv4str, sizeof ipv4str);
              sprintf(buf, "%s => %s\n", dom, ipv4str);
              printf("%s", buf);
              ++ipCount4;
              if (ucount4 < MAX_UNIQUE) {
                if (ucount4)
                  for (j = 0; j < ucount4; j++)
                    if (memcmp(addr4, unique4[j], 4) == 0) k = 0;
                if (k) {
                  memcpy(unique4[ucount4], addr4, 4);
                  ucount4++;
                }
              }
            }
          }
        }
      }
      freeaddrinfo(res);  // free the linked list
    }                     // end of if conditional
    // user wants delay between DNS requests?
    if (do_a_delay) dodelay(milliseconds);
    i++;
  }
  return;
}

int dnsquerycode(char *sub, char *domain, int type) {
  char vbuf[256], dom[256];

  memset(vbuf, 0, sizeof(vbuf));
  snprintf(dom, sizeof(dom), "%s.%s", sub, domain);
  res_query(dom, ns_c_in, type, vbuf, sizeof(vbuf));
  if (vbuf[2] == 0)
    return -1;
  else
    return (vbuf[3] & 15);
}

void threaded_resolve_srv(char *list[]) {
  char                 dom[MAXSTRSIZE] = "", buf[1024];
  int                  len, cnt, i, j, k, found = 0, found1, found4 = 0, found2;
  unsigned short int * port, *prio, *weight;
  unsigned char        vbuf[1500], *vptr;
  char                 dbuf[256];
  struct addrinfo      hints, *res, *p;
  struct sockaddr_in6 *ipv6, *q;
  char                 ipv6str[INET6_ADDRSTRLEN], ipv4str[16];
  struct sockaddr_in * ipv4, *q4;
  void *               addr, *addr4;

  if (type == NULL) return;
  memset((char *)&hints, 0, sizeof(hints));
  hints.ai_family = dof;

  i = 0;
  while (list != NULL && list[i] != NULL && list[i][0] != 0) {
    snprintf(dom, sizeof(dom), "%s.%s.%s", list[i], type, domain);
    memset(vbuf, 0, 4);
#if DEBUG
    printf("brute-forced domain: %s\n", dom);
#endif
    if ((len = res_query(dom, ns_c_in, ns_t_srv, vbuf, sizeof(vbuf))) > 0 &&
        (vbuf[3] & 15) == 0 && (cnt = vbuf[7]) > 0) {
      vptr = vbuf + strlen(dom) + 17;
      ucountsrv++;
      for (j = 0; j < cnt && len - (vptr - vbuf) >= 20; j++) {
        vptr += 10;
        k = vptr[1] + vptr[0] * 256;
        vptr += 2;
        prio = (unsigned short int *)(vptr);
        weight = (unsigned short int *)(vptr + 2);
        port = (unsigned short int *)(vptr + 4);
        dbuf[0] = 0;
        dn_expand(vbuf, vbuf + len, vptr + 6, dbuf, sizeof(dbuf));
        if (getaddrinfo(dbuf, NULL, &hints, &res) == 0) {
          q = NULL;
          q4 = NULL;
          found1 = 0;
          found2 = 0;
          for (p = res; p != NULL; p = p->ai_next) {
            if (do6 && p->ai_family == AF_INET6) {  // IPv6
              ipv6 = (struct sockaddr_in6 *)p->ai_addr;
              addr = &(ipv6->sin6_addr);
              if (q == NULL ||
                  memcmp(&ipv6->sin6_addr, &q->sin6_addr, 16) != 0) {
                q = ipv6;
                // convert the IP to a string and print it:
                inet_ntop(p->ai_family, addr, ipv6str, sizeof ipv6str);
                snprintf(buf, sizeof(buf),
                         "%s => %s is %s port %d %s (prio %d weight %d)\n", dom,
                         dbuf, ipv6str, htons(*port),
                         strcmp(type, "_tcp") == 0 ? "TCP" : "UDP",
                         htons(*prio), htons(*weight));
                printf("%s", buf);
                if (found1 == 0) {
                  ++found;
                  found1 = 1;
                }
              }
            } else if (do4 && p->ai_family == AF_INET) {  // IPv4
              ipv4 = (struct sockaddr_in *)p->ai_addr;
              addr4 = &(ipv4->sin_addr);
              if (q4 == NULL ||
                  memcmp(&ipv4->sin_addr, &q4->sin_addr, 4) != 0) {
                q4 = ipv4;
                // convert the IP to a string and print it:
                inet_ntop(p->ai_family, addr4, ipv4str, sizeof ipv4str);
                snprintf(buf, sizeof(buf),
                         "%s => %s is %s port %d %s (prio %d weight %d)\n", dom,
                         dbuf, ipv4str, htons(*port),
                         strcmp(type, "_tcp") == 0 ? "TCP" : "UDP",
                         htons(*prio), htons(*weight));
                printf("%s", buf);
                if (found2 == 0) {
                  ++found4;
                  found2 = 1;
                }
              }
            }
          }
          freeaddrinfo(res);
        } else {
          snprintf(buf, sizeof(buf),
                   "%s => %s port %d %s (prio %d weight %d)\n", dom, dbuf,
                   htons(*port), strcmp(type, "_tcp") == 0 ? "TCP" : "UDP",
                   htons(*prio), htons(*weight));
          printf("%s", buf);
        }
        vptr += k;
        ucountsrvs++;
      }
    }
    // else printf("srv: %s %d len %d code %d valid\n", dom, len, (vbuf[3] &
    // 15), vbuf[2]);

    if ((vbuf[3] & 15) == 0 && vbuf[2] > 0) {
      memset(vbuf, 0, 4);
      if ((len = res_query(dom, ns_c_in, ns_t_any, vbuf, sizeof(vbuf))) > 0 &&
          (vbuf[3] & 15) == 0 && (cnt = vbuf[7]) > 0) {
        if ((vbuf[2] & 2) == 2)
          fprintf(stderr,
                  "Warning: truncated answer for entry \"%s\" type ANY\n", dom);
        vptr = vbuf + strlen(dom) + 17;
        ucountsrv++;
        for (j = 0; j < cnt && len - (vptr - vbuf) >= 20; j++) {
          k = vptr[11] + vptr[10] * 256;
          if (vptr[2] == 0 && vptr[3] == 0x0c) {
            dbuf[0] = 0;
            dn_expand(vbuf, vbuf + len, vptr + 12, dbuf, sizeof(dbuf));
            if (getaddrinfo(dbuf, NULL, &hints, &res) == 0) {
              q = NULL;
              q4 = NULL;
              found1 = 0;
              found2 = 0;
              for (p = res; p != NULL; p = p->ai_next) {
                if (do6 && p->ai_family == AF_INET6) {  // IPv6
                  ipv6 = (struct sockaddr_in6 *)p->ai_addr;
                  addr = &(ipv6->sin6_addr);
                  if (q == NULL ||
                      memcmp(&ipv6->sin6_addr, &q->sin6_addr, 16) != 0) {
                    q = ipv6;
                    // convert the IP to a string and print it:
                    inet_ntop(p->ai_family, addr, ipv6str, sizeof ipv6str);
                    snprintf(buf, sizeof(buf), "%s => %s is %s\n", dom, dbuf,
                             ipv6str);
                    printf("%s", buf);
                    if (found1 == 0) {
                      ++found;
                      found1 = 1;
                    }
                  }
                } else if (do4 && p->ai_family == AF_INET) {  // IPv4
                  ipv4 = (struct sockaddr_in *)p->ai_addr;
                  addr4 = &(ipv4->sin_addr);
                  if (q4 == NULL ||
                      memcmp(&ipv4->sin_addr, &q4->sin_addr, 4) != 0) {
                    q4 = ipv4;
                    // convert the IP to a string and print it:
                    inet_ntop(p->ai_family, addr4, ipv4str, sizeof(ipv4str));
                    snprintf(buf, sizeof(buf), "%s => %s is %s\n", dom, dbuf,
                             ipv4str);
                    printf("%s", buf);
                    if (found2 == 0) {
                      ++found4;
                      found2 = 1;
                    }
                  }
                }
              }
              freeaddrinfo(res);
            } else {
              snprintf(buf, sizeof(buf), "%s => %s\n", dom, dbuf);
              printf("%s", buf);
            }
          }
          vptr += k + 12;
          ucountsrvs++;
        }
      }
      // else printf("ptr: %s %d len %d code %d valid\n", dom, len, (vbuf[3] &
      // 15), vbuf[2]);
    }
    // user wants delay between DNS requests?
    if (do_a_delay) dodelay(milliseconds);
    i++;
  }
  return;
}

// there be dragons. This might have a buffer overflow in here if the dns
// server sends a malformed DNS reply. luckily we dont copy anything here.
void dump_dns(char *dom, int type) {
  int len, cnt, i, j, found = 0, found1, found4 = 0, allfound = 0, found2;
  unsigned char        vbuf[1500], *vptr = vbuf + 2;
  char                 dbuf[256], fbuf[256][256];
  struct addrinfo      hints, *res, *p;
  struct sockaddr_in6 *ipv6, *q;
  char                 ipv6str[INET6_ADDRSTRLEN], ipv4str[16];
  struct sockaddr_in * ipv4, *q4;
  void *               addr, *addr4;

  memset((char *)&hints, 0, sizeof(hints));
  hints.ai_family = dof;
  if (((len = res_query(dom, ns_c_in, type, vbuf, sizeof(vbuf))) <
       (30 + strlen(dom))) ||
      ((*vptr & 0x82) != 0x80) || ((*(vptr + 1) & 0x0f) != 0)) {
    fprintf(stderr, "Warning: no %s information found\n",
            type == ns_t_ns ? "name server (NS)" : "mail server (MX)");
    return;
  }
  vptr += 4;
  cnt = *vptr * 256 + *(vptr + 1);
  if (cnt < 1 || cnt > 16) {
    fprintf(stderr, "Warning: no %s information found\n",
            type == ns_t_ns ? "name server (NS)" : "mail server (MX)");
    return;
  }
  vptr += 6;
  vptr += strlen(dom) + 1;
  vptr += 4;
  // we are no at the beginning of the answer section
  do {
    vptr += 10;
    if (type == ns_t_mx) vptr += 2;
    dbuf[0] = 0;
    dn_expand(vbuf, vbuf + len, vptr + 2, dbuf, sizeof(dbuf));
#if DEBUG
    printf("Found %s for %s: %s\n", type == ns_t_mx ? "MX" : "NS", dom, dbuf);
#endif
    if (vptr < vbuf + len && dbuf[0] != 0) {  // BOF protection
      dbuf[255] = 0;
      i = 0;
      if (allfound > 0) {
        for (j = 0; j < allfound; j++)
          if (strcmp(dbuf, fbuf[j]) == 0) i = 1;
      }
      strcpy(fbuf[allfound], dbuf);
      allfound++;
      if (i == 0 && getaddrinfo(dbuf, NULL, &hints, &res) == 0) {
        q = NULL;
        q4 = NULL;
        found1 = 0;
        found2 = 0;
        for (p = res; p != NULL; p = p->ai_next) {
          if (do6 && p->ai_family == AF_INET6) {  // IPv6
            ipv6 = (struct sockaddr_in6 *)p->ai_addr;
            addr = &(ipv6->sin6_addr);
            if (q == NULL || memcmp(&ipv6->sin6_addr, &q->sin6_addr, 16) != 0) {
              q = ipv6;
              // convert the IP to a string and print it:
              inet_ntop(p->ai_family, addr, ipv6str, sizeof ipv6str);
              printf("%s of %s is %s. => %s\n", type == ns_t_mx ? "MX" : "NS",
                     dom, dbuf, ipv6str);
              if (found1 == 0) {
                ++found;
                found1 = 1;
              }
            }
          } else if (do4 && p->ai_family == AF_INET) {  // IPv4
            ipv4 = (struct sockaddr_in *)p->ai_addr;
            addr4 = &(ipv4->sin_addr);
            if (q4 == NULL || memcmp(&ipv4->sin_addr, &q4->sin_addr, 4) != 0) {
              q4 = ipv4;
              // convert the IP to a string and print it:
              inet_ntop(p->ai_family, addr4, ipv4str, sizeof ipv4str);
              printf("%s of %s is %s. => %s\n", type == ns_t_mx ? "MX" : "NS",
                     dom, dbuf, ipv4str);
              if (found2 == 0) {
                ++found4;
                found2 = 1;
              }
            }
          }
        }
        freeaddrinfo(res);
      }
    }
    if (type == ns_t_ns)
      vptr += vptr[1] + 2;
    else
      vptr += vptr[-1];
    cnt--;
  } while (vptr < vbuf + len && cnt > 0);
  if (found == 0 && do6)
    printf("No IPv6 address for %s entries found in DNS for domain %s\n",
           type == ns_t_mx ? "MX" : "NS", dom);
  if (found4 == 0 && do4)
    printf("No IPv4 address for %s entries found in DNS for domain %s\n",
           type == ns_t_mx ? "MX" : "NS", dom);
}

int main(int argc, char *argv[]) {
  unsigned short    wordlist = FALSE, threads = 8, dumpit = 0, showdns = 0;
  unsigned long int wcount = 0;
  int               i = 0, j, k, ignore_ns_error = 0;
  char              dom[MAXSTRSIZE] = "", *wordlistFilename = NULL;
  FILE *            fpWords;
  char              typ = 't', **sub_orig;
  pthread_t         thread[MAX_THREADS];

  setvbuf(stdout, NULL, _IONBF, 0);
  setvbuf(stderr, NULL, _IONBF, 0);

  if (getenv("THC_IPV6_PPPOE") != NULL || getenv("THC_IPV6_6IN4") != NULL)
    printf("WARNING: %s is not working with injection!\n", argv[0]);

  do4 = 1;
  do6 = 1;
  if (argv[0] != NULL && argv[0][0] != 0) i = argv[0][strlen(argv[0]) - 1];
  if (i == '4') do6 = 0;
  if (i == '6') do4 = 0;

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

  while ((i = getopt(argc, argv, "det:smlxuSD46")) >= 0) {
    switch (i) {
      case '4':
        do4 = 1;
        break;
      case '6':
        do6 = 0;
        break;
      case 'd':
        showdns = 1;
        break;
      case 'e':
        ignore_ns_error = 1;
        break;
      case 't':
        threads = atoi(optarg);
        break;
      case 's':
        sub = (char **)sub_small;
        break;
      case 'm':
        sub = (char **)sub_medium;
        break;
      case 'l':
        sub = (char **)sub_large;
        break;
      case 'x':
        sub = (char **)sub_xtreme;
        break;
      case 'u':
        sub = (char **)sub_uber;
        break;
      case 'D':
        dumpit = 1;
        break;
      case 'S':
        dosrv = 1;
        break;
      default:
        fprintf(stderr, "Error: unknown option -%c\n", i);
        exit(-1);
    }
  }

  if (do4 && do6)
    dof = 0;
  else if (do4 && do6 == 0)
    dof = AF_INET;
  else
    dof = AF_INET6;

  if (threads > MAX_THREADS) {
    threads = MAX_THREADS;
    fprintf(stderr, "Warning: setting threats to maximum of %d\n", threads);
  }
  if (threads < 1) threads = 1;

  if (dumpit) {
    i = 0;
    while (sub[i] != NULL && sub[i][0] != 0)
      printf("%s\n", sub[i++]);
    exit(0);
  }

  if (argc == optind || argc > optind + 2) {
    fprintf(stderr, "Error: invalid options, try \"-h\" for help!\n");
    exit(-1);
  }

  if (argc > (optind + 1)) {
    wordlist = TRUE;
    wordlistFilename = argv[optind + 1];
  }

  for (i = 0; argv[optind][i]; ++i)  // convert domain to lower case
    argv[optind][i] = (tolower(argv[optind][i]));
  strcpy(domain, argv[optind]);
  if (domain[strlen(domain) - 1] == '.') domain[strlen(domain) - 1] = 0;
#if DEBUG
  printf("domain: %s\n", domain);
#endif
  if (isValidDomain(domain) < 0) {
    fprintf(stderr, "Error: domain seems not to be valid: %s\n", domain);
    exit(-1);
  }

  strcat(domain, ".");
  if (verifyDomain(domain) != TRUE) {
    fprintf(stderr, "Error: no name server (NS) entry for domain %s exists\n",
            domain);
    if (ignore_ns_error == 0) exit(-1);
  }

  printf("Starting DNS enumeration work on %s ...\n", domain);

  if (showdns) {
    printf("Gathering NS and MX information...\n");
    dump_dns(domain, ns_t_ns);
    dump_dns(domain, ns_t_mx);
    printf("\n");
  }

  if (dosrv) {
    sub_orig = sub;
    sub = (char **)sub_srv;

    printf("Starting SRV service enumeration\n");
    printf("Estimated time to completion: 1 to 4 minutes\n");

    lists = malloc(threads * sizeof(void *));
    for (i = 0; i < threads; i++) {
      listptr[i] = 0;
      lists[i] = malloc(65536 * sizeof(int));
    }
    i = j = 0;
    while (sub[j] != NULL && sub[j][0] != 0) {
      lists[i][listptr[i]] = malloc(strlen(sub[j]) + 1);
      strcpy(lists[i][listptr[i]], sub[j]);
      listptr[i] += 1;
      i++;
      if (i >= threads) i = 0;
      wcount++;
      j++;
    }
    for (k = 0; k < threads; k++) {
      lists[k][listptr[k]] = malloc(2);
      lists[k][listptr[k]][0] = 0;
      lists[k][listptr[k] + 1] = NULL;
    }

    type = "_tcp";
    if (dnsquerycode(type, domain, ns_t_srv) == 0) {
      dosrv++;
      for (i = 0; i < threads; i++)
        pthread_create(&thread[i], NULL, (void *)threaded_resolve_srv,
                       (void *)lists[i]);
      for (i = 0; i < threads; i++)
        pthread_join(thread[i], NULL);
    } else
      printf("No SRV entries for TCP\n");
    type = "_udp";
    if (dnsquerycode(type, domain, ns_t_srv) == 0) {
      dosrv++;
      for (i = 0; i < threads; i++)
        pthread_create(&thread[i], NULL, (void *)threaded_resolve_srv,
                       (void *)lists[i]);
      for (i = 0; i < threads; i++)
        pthread_join(thread[i], NULL);
    } else
      printf("No SRV entries for UDP\n");

    if (dosrv > 1)
      printf("Found %d services with %d entries altogether\n\n", ucountsrv,
             ucountsrvs);
    sub = sub_orig;
    type = NULL;
  }

  lists = malloc(threads * sizeof(void *));
  for (i = 0; i < threads; i++) {
    listptr[i] = 0;
    lists[i] = malloc(65536 * sizeof(int));
  }

  wcount = 0;
  // split wordlist to thread lists
  if (wordlist == TRUE) {
    fpWords = fopen(wordlistFilename, "r");
    if (fpWords) {
      i = 0;
      while (!feof(fpWords)) {
        j = fscanf(
            fpWords, "%100s",
            dom);  // wordlist subdomain not allowed to be more than 100 chars
        // put in list here
        lists[i][listptr[i]] = malloc(strlen(dom) + 1);
        strcpy(lists[i][listptr[i]], dom);
        listptr[i] += 1;
        if (listptr[i] >= 65534) {
          fprintf(stderr, "Error: wordlist too large (max: %d)!\n",
                  65536 * threads);
          exit(-1);
        }
        i++;
        wcount++;
        if (i >= threads) i = 0;
      }
    } else {
      fprintf(stderr, "Error: could not open file %s\n", wordlistFilename);
      exit(-1);
    }
    fclose(fpWords);
  } else {
    i = j = 0;
    while (sub[j] != NULL && sub[j][0] != 0) {
      lists[i][listptr[i]] = malloc(strlen(sub[j]) + 1);
      strcpy(lists[i][listptr[i]], sub[j]);
      listptr[i] += 1;
      i++;
      if (i >= threads) i = 0;
      wcount++;
      j++;
    }
  }
  for (k = 0; k < threads; k++) {
    lists[k][listptr[k]] = malloc(2);
    lists[k][listptr[k]][0] = 0;
    lists[k][listptr[k] + 1] = NULL;
  }

  if (wcount < threads) threads = wcount;

  printf("Starting enumerating %s - creating %d threads for %d words...\n",
         domain, threads, (int)wcount);
  printf("Estimated time to completion: %d to %d minute%s\n",
         (int)((wcount / 300) / threads) + 1,
         (int)((wcount / 90) / threads) + 1,
         ((wcount / 60) / threads) + 1 > 1 ? "s" : "");
  // wildcard detection
  wildcarDetect(domain);
  for (i = 0; i < threads; i++)
    pthread_create(&thread[i], NULL, (void *)threaded_resolve,
                   (void *)lists[i]);
  for (i = 0; i < threads; i++)
    pthread_join(thread[i], NULL);
  if (do4 && do6)
    printf(
        "\nFound %d domain name%s, %d unique ipv4 and %d unique ipv6 addresses "
        "for %s\n",
        found, found == 1 ? "" : "s", ucount4 + wcard4, ucount + wcard, domain);
  else if (do4)
    printf("\nFound %d domain name%s and %d unique ipv4 address%s for %s\n",
           found, found == 1 ? "" : "s", ucount4 + wcard4,
           (ucount4 + wcard4) == 1 ? "" : "s", domain);
  else
    printf("\nFound %d domain name%s and %d unique ipv6 address%s for %s\n",
           found, found == 1 ? "" : "s", ucount + wcard,
           (ucount + wcard) == 1 ? "" : "s", domain);

  return 0;
}