src/tools/adig.c

/* MIT License
 *
 * Copyright (c) 1998 Massachusetts Institute of Technology
 * Copyright (c) The c-ares project and its contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * SPDX-License-Identifier: MIT
 */
#include "ares_setup.h"

#ifdef HAVE_NETINET_IN_H
#  include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#  include <arpa/inet.h>
#endif
#ifdef HAVE_NETDB_H
#  include <netdb.h>
#endif

#include "ares_nameser.h"

#ifdef HAVE_STRINGS_H
#  include <strings.h>
#endif

#include "ares.h"
#include "ares_dns.h"

#ifndef HAVE_STRDUP
#  include "ares_str.h"
#  define strdup(ptr) ares_strdup(ptr)
#endif

#ifndef HAVE_STRCASECMP
#  include "ares_strcasecmp.h"
#  define strcasecmp(p1, p2) ares_strcasecmp(p1, p2)
#endif

#ifndef HAVE_STRNCASECMP
#  include "ares_strcasecmp.h"
#  define strncasecmp(p1, p2, n) ares_strncasecmp(p1, p2, n)
#endif

#include "ares_getopt.h"

#ifdef WATT32
#  undef WIN32 /* Redefined in MingW headers */
#endif


typedef struct {
  ares_bool_t         is_help;
  struct ares_options options;
  int                 optmask;
  ares_dns_class_t    qclass;
  ares_dns_rec_type_t qtype;
  int                 args_processed;
  char               *servers;
  char                error[256];
} adig_config_t;

typedef struct {
  const char *name;
  int         value;
} nv_t;

static const nv_t configflags[] = {
  {"usevc",      ARES_FLAG_USEVC    },
  { "primary",   ARES_FLAG_PRIMARY  },
  { "igntc",     ARES_FLAG_IGNTC    },
  { "norecurse", ARES_FLAG_NORECURSE},
  { "stayopen",  ARES_FLAG_STAYOPEN },
  { "noaliases", ARES_FLAG_NOALIASES}
};
static const size_t nconfigflags = sizeof(configflags) / sizeof(*configflags);

static int          lookup_flag(const nv_t *nv, size_t num_nv, const char *name)
{
  size_t i;

  if (name == NULL) {
    return 0;
  }

  for (i = 0; i < num_nv; i++) {
    if (strcasecmp(nv[i].name, name) == 0) {
      return nv[i].value;
    }
  }

  return 0;
}

static void free_config(adig_config_t *config)
{
  free(config->servers);
  memset(config, 0, sizeof(*config));
}

static void print_help(void)
{
  printf("adig version %s\n\n", ares_version(NULL));
  printf(
    "usage: adig [-h] [-d] [-f flag] [[-s server] ...] [-T|U port] [-c class]\n"
    "            [-t type] name ...\n\n"
    "  -h : Display this help and exit.\n"
    "  -d : Print some extra debugging output.\n"
    "  -f flag   : Add a behavior control flag. Possible values are\n"
    "              igntc     - do not retry a truncated query as TCP, just\n"
    "                          return the truncated answer\n"
    "              noaliases - don't honor the HOSTALIASES environment\n"
    "                          variable\n"
    "              norecurse - don't query upstream servers recursively\n"
    "              primary   - use the first server\n"
    "              stayopen  - don't close the communication sockets\n"
    "              usevc     - use TCP only\n"
    "  -s server : Connect to the specified DNS server, instead of the\n"
    "              system's default one(s). Servers are tried in round-robin,\n"
    "              if the previous one failed.\n"
    "  -T port   : Connect to the specified TCP port of DNS server.\n"
    "  -U port   : Connect to the specified UDP port of DNS server.\n"
    "  -c class  : Set the query class. Possible values for class are:\n"
    "              ANY, CHAOS, HS and IN (default)\n"
    "  -t type   : Query records of the specified type. Possible values for\n"
    "              type are:\n"
    "              A (default), AAAA, ANY, CNAME, HINFO, MX, NAPTR, NS, PTR,\n"
    "              SOA, SRV, TXT, TLSA, URI, CAA, SVCB, HTTPS\n\n");
}

static ares_bool_t read_cmdline(int argc, const char **argv,
                                adig_config_t *config)
{
  ares_getopt_state_t state;
  int                 c;

  ares_getopt_init(&state, argc, argv);
  state.opterr = 0;

  while ((c = ares_getopt(&state, "dh?f:s:c:t:T:U:")) != -1) {
    int f;

    switch (c) {
      case 'd':
#ifdef WATT32
        dbug_init();
#endif
        break;

      case 'h':
        config->is_help = ARES_TRUE;
        return ARES_TRUE;

      case 'f':
        f = lookup_flag(configflags, nconfigflags, state.optarg);
        if (f == 0) {
          snprintf(config->error, sizeof(config->error), "flag %s unknown",
                   state.optarg);
        }

        config->options.flags |= f;
        config->optmask       |= ARES_OPT_FLAGS;
        break;

      case 's':
        if (state.optarg == NULL) {
          snprintf(config->error, sizeof(config->error), "%s",
                   "missing servers");
          return ARES_FALSE;
        }
        if (config->servers) {
          free(config->servers);
        }
        config->servers = strdup(state.optarg);
        break;

      case 'c':
        if (!ares_dns_class_fromstr(&config->qclass, state.optarg)) {
          snprintf(config->error, sizeof(config->error),
                   "unrecognized class %s", state.optarg);
          return ARES_FALSE;
        }
        break;

      case 't':
        if (!ares_dns_rec_type_fromstr(&config->qtype, state.optarg)) {
          snprintf(config->error, sizeof(config->error), "unrecognized type %s",
                   state.optarg);
          return ARES_FALSE;
        }
        break;

      case 'T':
        /* Set the TCP port number. */
        if (!isdigit(*state.optarg)) {
          snprintf(config->error, sizeof(config->error), "invalid port number");
          return ARES_FALSE;
        }
        config->options.tcp_port =
          (unsigned short)strtol(state.optarg, NULL, 0);
        config->options.flags |= ARES_FLAG_USEVC;
        config->optmask       |= ARES_OPT_TCP_PORT;
        break;

      case 'U':
        /* Set the UDP port number. */
        if (!isdigit(*state.optarg)) {
          snprintf(config->error, sizeof(config->error), "invalid port number");
          return ARES_FALSE;
        }
        config->options.udp_port =
          (unsigned short)strtol(state.optarg, NULL, 0);
        config->optmask |= ARES_OPT_UDP_PORT;
        break;

      case ':':
        snprintf(config->error, sizeof(config->error),
                 "%c requires an argument", state.optopt);
        return ARES_FALSE;

      default:
        snprintf(config->error, sizeof(config->error),
                 "unrecognized option: %c", state.optopt);
        return ARES_FALSE;
    }
  }

  config->args_processed = state.optind;
  if (config->args_processed >= argc) {
    snprintf(config->error, sizeof(config->error), "missing query name");
    return ARES_FALSE;
  }
  return ARES_TRUE;
}

static void print_flags(ares_dns_flags_t flags)
{
  if (flags & ARES_FLAG_QR) {
    printf(" qr");
  }
  if (flags & ARES_FLAG_AA) {
    printf(" aa");
  }
  if (flags & ARES_FLAG_TC) {
    printf(" tc");
  }
  if (flags & ARES_FLAG_RD) {
    printf(" rd");
  }
  if (flags & ARES_FLAG_RA) {
    printf(" ra");
  }
  if (flags & ARES_FLAG_AD) {
    printf(" ad");
  }
  if (flags & ARES_FLAG_CD) {
    printf(" cd");
  }
}

static void print_header(const ares_dns_record_t *dnsrec)
{
  printf(";; ->>HEADER<<- opcode: %s, status: %s, id: %u\n",
         ares_dns_opcode_tostr(ares_dns_record_get_opcode(dnsrec)),
         ares_dns_rcode_tostr(ares_dns_record_get_rcode(dnsrec)),
         ares_dns_record_get_id(dnsrec));
  printf(";; flags:");
  print_flags(ares_dns_record_get_flags(dnsrec));
  printf("; QUERY: %u, ANSWER: %u, AUTHORITY: %u, ADDITIONAL: %u\n\n",
         (unsigned int)ares_dns_record_query_cnt(dnsrec),
         (unsigned int)ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_ANSWER),
         (unsigned int)ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_AUTHORITY),
         (unsigned int)ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_ADDITIONAL));
}

static void print_question(const ares_dns_record_t *dnsrec)
{
  size_t i;
  printf(";; QUESTION SECTION:\n");
  for (i = 0; i < ares_dns_record_query_cnt(dnsrec); i++) {
    const char         *name;
    ares_dns_rec_type_t qtype;
    ares_dns_class_t    qclass;
    size_t              len;
    if (ares_dns_record_query_get(dnsrec, i, &name, &qtype, &qclass) !=
        ARES_SUCCESS) {
      return;
    }
    if (name == NULL) {
      return;
    }
    len = strlen(name);
    printf(";%s.\t", name);
    if (len + 1 < 24) {
      printf("\t");
    }
    if (len + 1 < 16) {
      printf("\t");
    }
    printf("%s\t%s\n", ares_dns_class_tostr(qclass),
           ares_dns_rec_type_tostr(qtype));
  }
  printf("\n");
}

static void print_opt_none(const unsigned char *val, size_t val_len)
{
  (void)val;
  if (val_len != 0) {
    printf("INVALID!");
  }
}

static void print_opt_addr_list(const unsigned char *val, size_t val_len)
{
  size_t i;
  if (val_len % 4 != 0) {
    printf("INVALID!");
    return;
  }
  for (i = 0; i < val_len; i += 4) {
    char buf[256] = "";
    ares_inet_ntop(AF_INET, val + i, buf, sizeof(buf));
    if (i != 0) {
      printf(",");
    }
    printf("%s", buf);
  }
}

static void print_opt_addr6_list(const unsigned char *val, size_t val_len)
{
  size_t i;
  if (val_len % 16 != 0) {
    printf("INVALID!");
    return;
  }
  for (i = 0; i < val_len; i += 16) {
    char buf[256] = "";

    ares_inet_ntop(AF_INET6, val + i, buf, sizeof(buf));
    if (i != 0) {
      printf(",");
    }
    printf("%s", buf);
  }
}

static void print_opt_u8_list(const unsigned char *val, size_t val_len)
{
  size_t i;

  for (i = 0; i < val_len; i++) {
    if (i != 0) {
      printf(",");
    }
    printf("%u", (unsigned int)val[i]);
  }
}

static void print_opt_u16_list(const unsigned char *val, size_t val_len)
{
  size_t i;
  if (val_len < 2 || val_len % 2 != 0) {
    printf("INVALID!");
    return;
  }
  for (i = 0; i < val_len; i += 2) {
    unsigned short u16 = 0;
    unsigned short c;
    /* Jumping over backwards to try to avoid odd compiler warnings */
    c    = (unsigned short)val[i];
    u16 |= (unsigned short)((c << 8) & 0xFFFF);
    c    = (unsigned short)val[i + 1];
    u16 |= c;
    if (i != 0) {
      printf(",");
    }
    printf("%u", (unsigned int)u16);
  }
}

static void print_opt_u32_list(const unsigned char *val, size_t val_len)
{
  size_t i;
  if (val_len < 4 || val_len % 4 != 0) {
    printf("INVALID!");
    return;
  }
  for (i = 0; i < val_len; i += 4) {
    unsigned int u32 = 0;

    u32 |= (unsigned int)(val[i] << 24);
    u32 |= (unsigned int)(val[i + 1] << 16);
    u32 |= (unsigned int)(val[i + 2] << 8);
    u32 |= (unsigned int)(val[i + 3]);
    if (i != 0) {
      printf(",");
    }
    printf("%u", u32);
  }
}

static void print_opt_str_list(const unsigned char *val, size_t val_len)
{
  size_t cnt = 0;

  printf("\"");
  while (val_len) {
    long           read_len = 0;
    unsigned char *str      = NULL;
    ares_status_t  status;

    if (cnt) {
      printf(",");
    }

    status = (ares_status_t)ares_expand_string(val, val, (int)val_len, &str,
                                               &read_len);
    if (status != ARES_SUCCESS) {
      printf("INVALID");
      break;
    }
    printf("%s", str);
    ares_free_string(str);
    val_len -= (size_t)read_len;
    val     += read_len;
    cnt++;
  }
  printf("\"");
}

static void print_opt_name(const unsigned char *val, size_t val_len)
{
  char *str      = NULL;
  long  read_len = 0;

  if (ares_expand_name(val, val, (int)val_len, &str, &read_len) !=
      ARES_SUCCESS) {
    printf("INVALID!");
    return;
  }

  printf("%s.", str);
  ares_free_string(str);
}

static void print_opt_bin(const unsigned char *val, size_t val_len)
{
  size_t i;

  for (i = 0; i < val_len; i++) {
    printf("%02x", (unsigned int)val[i]);
  }
}

static ares_bool_t adig_isprint(int ch)
{
  if (ch >= 0x20 && ch <= 0x7E) {
    return ARES_TRUE;
  }
  return ARES_FALSE;
}

static void print_opt_binp(const unsigned char *val, size_t val_len)
{
  size_t i;
  printf("\"");
  for (i = 0; i < val_len; i++) {
    if (adig_isprint(val[i])) {
      printf("%c", val[i]);
    } else {
      printf("\\%03d", val[i]);
    }
  }
  printf("\"");
}

static void print_opts(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  size_t i;

  for (i = 0; i < ares_dns_rr_get_opt_cnt(rr, key); i++) {
    size_t               val_len = 0;
    const unsigned char *val     = NULL;
    unsigned short       opt;
    const char          *name;

    if (i != 0) {
      printf(" ");
    }

    opt  = ares_dns_rr_get_opt(rr, key, i, &val, &val_len);
    name = ares_dns_opt_get_name(key, opt);
    if (name == NULL) {
      printf("key%u", (unsigned int)opt);
    } else {
      printf("%s", name);
    }
    if (val_len == 0) {
      return;
    }

    printf("=");

    switch (ares_dns_opt_get_datatype(key, opt)) {
      case ARES_OPT_DATATYPE_NONE:
        print_opt_none(val, val_len);
        break;
      case ARES_OPT_DATATYPE_U8_LIST:
        print_opt_u8_list(val, val_len);
        break;
      case ARES_OPT_DATATYPE_INADDR4_LIST:
        print_opt_addr_list(val, val_len);
        break;
      case ARES_OPT_DATATYPE_INADDR6_LIST:
        print_opt_addr6_list(val, val_len);
        break;
      case ARES_OPT_DATATYPE_U16:
      case ARES_OPT_DATATYPE_U16_LIST:
        print_opt_u16_list(val, val_len);
        break;
      case ARES_OPT_DATATYPE_U32:
      case ARES_OPT_DATATYPE_U32_LIST:
        print_opt_u32_list(val, val_len);
        break;
      case ARES_OPT_DATATYPE_STR_LIST:
        print_opt_str_list(val, val_len);
        break;
      case ARES_OPT_DATATYPE_BIN:
        print_opt_bin(val, val_len);
        break;
      case ARES_OPT_DATATYPE_NAME:
        print_opt_name(val, val_len);
        break;
    }
  }
}

static void print_addr(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  const struct in_addr *addr     = ares_dns_rr_get_addr(rr, key);
  char                  buf[256] = "";

  ares_inet_ntop(AF_INET, addr, buf, sizeof(buf));
  printf("%s", buf);
}

static void print_addr6(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  const struct ares_in6_addr *addr     = ares_dns_rr_get_addr6(rr, key);
  char                        buf[256] = "";

  ares_inet_ntop(AF_INET6, addr, buf, sizeof(buf));
  printf("%s", buf);
}

static void print_u8(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  unsigned char u8 = ares_dns_rr_get_u8(rr, key);
  printf("%u", (unsigned int)u8);
}

static void print_u16(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  unsigned short u16 = ares_dns_rr_get_u16(rr, key);
  printf("%u", (unsigned int)u16);
}

static void print_u32(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  unsigned int u32 = ares_dns_rr_get_u32(rr, key);
  printf("%u", u32);
}

static void print_name(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  const char *str = ares_dns_rr_get_str(rr, key);
  printf("%s.", str);
}

static void print_str(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  const char *str = ares_dns_rr_get_str(rr, key);
  printf("\"%s\"", str);
}

static void print_bin(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  size_t               len  = 0;
  const unsigned char *binp = ares_dns_rr_get_bin(rr, key, &len);
  print_opt_bin(binp, len);
}

static void print_binp(const ares_dns_rr_t *rr, ares_dns_rr_key_t key)
{
  size_t               len;
  const unsigned char *binp = ares_dns_rr_get_bin(rr, key, &len);

  print_opt_binp(binp, len);
}

static void print_rr(const ares_dns_rr_t *rr)
{
  const char              *name     = ares_dns_rr_get_name(rr);
  size_t                   len      = 0;
  size_t                   keys_cnt = 0;
  ares_dns_rec_type_t      rtype    = ares_dns_rr_get_type(rr);
  const ares_dns_rr_key_t *keys     = ares_dns_rr_get_keys(rtype, &keys_cnt);
  size_t                   i;

  if (name == NULL) {
    return;
  }

  len = strlen(name);

  printf("%s.\t", name);
  if (len < 24) {
    printf("\t");
  }

  printf("%u\t%s\t%s\t", ares_dns_rr_get_ttl(rr),
         ares_dns_class_tostr(ares_dns_rr_get_class(rr)),
         ares_dns_rec_type_tostr(rtype));

  /* Output params here */
  for (i = 0; i < keys_cnt; i++) {
    ares_dns_datatype_t datatype = ares_dns_rr_key_datatype(keys[i]);
    if (i != 0) {
      printf(" ");
    }

    switch (datatype) {
      case ARES_DATATYPE_INADDR:
        print_addr(rr, keys[i]);
        break;
      case ARES_DATATYPE_INADDR6:
        print_addr6(rr, keys[i]);
        break;
      case ARES_DATATYPE_U8:
        print_u8(rr, keys[i]);
        break;
      case ARES_DATATYPE_U16:
        print_u16(rr, keys[i]);
        break;
      case ARES_DATATYPE_U32:
        print_u32(rr, keys[i]);
        break;
      case ARES_DATATYPE_NAME:
        print_name(rr, keys[i]);
        break;
      case ARES_DATATYPE_STR:
        print_str(rr, keys[i]);
        break;
      case ARES_DATATYPE_BIN:
        print_bin(rr, keys[i]);
        break;
      case ARES_DATATYPE_BINP:
        print_binp(rr, keys[i]);
        break;
      case ARES_DATATYPE_OPT:
        print_opts(rr, keys[i]);
        break;
    }
  }

  printf("\n");
}

static const ares_dns_rr_t *has_opt(ares_dns_record_t *dnsrec,
                                    ares_dns_section_t section)
{
  size_t i;
  for (i = 0; i < ares_dns_record_rr_cnt(dnsrec, section); i++) {
    const ares_dns_rr_t *rr = ares_dns_record_rr_get(dnsrec, section, i);
    if (ares_dns_rr_get_type(rr) == ARES_REC_TYPE_OPT) {
      return rr;
    }
  }
  return NULL;
}

static void print_section(ares_dns_record_t *dnsrec, ares_dns_section_t section)
{
  size_t i;

  if (ares_dns_record_rr_cnt(dnsrec, section) == 0 ||
      (ares_dns_record_rr_cnt(dnsrec, section) == 1 &&
       has_opt(dnsrec, section) != NULL)) {
    return;
  }

  printf(";; %s SECTION:\n", ares_dns_section_tostr(section));
  for (i = 0; i < ares_dns_record_rr_cnt(dnsrec, section); i++) {
    const ares_dns_rr_t *rr = ares_dns_record_rr_get(dnsrec, section, i);
    if (ares_dns_rr_get_type(rr) == ARES_REC_TYPE_OPT) {
      continue;
    }
    print_rr(rr);
  }
  printf("\n");
}

static void print_opt_psuedosection(ares_dns_record_t *dnsrec)
{
  const ares_dns_rr_t *rr = has_opt(dnsrec, ARES_SECTION_ADDITIONAL);
  if (rr == NULL) {
    return;
  }

  printf(";; OPT PSEUDOSECTION:\n");
  printf("; EDNS: version: %u, flags: %u; udp: %u\t",
         (unsigned int)ares_dns_rr_get_u8(rr, ARES_RR_OPT_VERSION),
         (unsigned int)ares_dns_rr_get_u16(rr, ARES_RR_OPT_FLAGS),
         (unsigned int)ares_dns_rr_get_u16(rr, ARES_RR_OPT_UDP_SIZE));

  printf("\n");
}

static void callback(void *arg, int status, int timeouts, unsigned char *abuf,
                     int alen)
{
  ares_dns_record_t *dnsrec = NULL;
  (void)arg;
  (void)timeouts;

  /* We got a "Server status" */
  if (status >= ARES_SUCCESS && status <= ARES_EREFUSED) {
    printf(";; Got answer:");
  } else {
    printf(";;");
  }

  if (status != ARES_SUCCESS) {
    printf(" %s", ares_strerror(status));
  }
  printf("\n");

  if (abuf == NULL || alen == 0) {
    return;
  }

  status = (int)ares_dns_parse(abuf, (size_t)alen, 0, &dnsrec);
  if (status != ARES_SUCCESS) {
    fprintf(stderr, ";; FAILED TO PARSE DNS PACKET: %s\n",
            ares_strerror(status));
    return;
  }

  print_header(dnsrec);
  print_opt_psuedosection(dnsrec);
  print_question(dnsrec);
  print_section(dnsrec, ARES_SECTION_ANSWER);
  print_section(dnsrec, ARES_SECTION_ADDITIONAL);
  print_section(dnsrec, ARES_SECTION_AUTHORITY);

  printf(";; MSG SIZE  rcvd: %d\n\n", alen);
  ares_dns_record_destroy(dnsrec);
}

static ares_status_t enqueue_query(ares_channel_t      *channel,
                                   const adig_config_t *config,
                                   const char          *name)
{
  ares_dns_record_t *dnsrec = NULL;
  ares_dns_rr_t     *rr     = NULL;
  ares_status_t      status;
  unsigned char     *buf      = NULL;
  size_t             buf_len  = 0;
  unsigned short     flags    = 0;
  char              *nametemp = NULL;

  if (!(config->options.flags & ARES_FLAG_NORECURSE)) {
    flags |= ARES_FLAG_RD;
  }

  status = ares_dns_record_create(&dnsrec, 0, flags, ARES_OPCODE_QUERY,
                                  ARES_RCODE_NOERROR);
  if (status != ARES_SUCCESS) {
    goto done;
  }

  /* If it is a PTR record, convert from ip address into in-arpa form
   * automatically */
  if (config->qtype == ARES_REC_TYPE_PTR) {
    struct ares_addr addr;
    size_t           len;
    addr.family = AF_UNSPEC;

    if (ares_dns_pton(name, &addr, &len) != NULL) {
      nametemp = ares_dns_addr_to_ptr(&addr);
      name     = nametemp;
    }
  }

  status =
    ares_dns_record_query_add(dnsrec, name, config->qtype, config->qclass);
  if (status != ARES_SUCCESS) {
    goto done;
  }

  status = ares_dns_record_rr_add(&rr, dnsrec, ARES_SECTION_ADDITIONAL, "",
                                  ARES_REC_TYPE_OPT, ARES_CLASS_IN, 0);
  if (status != ARES_SUCCESS) {
    goto done;
  }
  ares_dns_rr_set_u16(rr, ARES_RR_OPT_UDP_SIZE, 1280);
  ares_dns_rr_set_u8(rr, ARES_RR_OPT_VERSION, 0);

  status = ares_dns_write(dnsrec, &buf, &buf_len);
  if (status != ARES_SUCCESS) {
    goto done;
  }

  ares_send(channel, buf, (int)buf_len, callback, NULL);
  ares_free_string(buf);

done:
  ares_free_string(nametemp);
  ares_dns_record_destroy(dnsrec);
  return status;
}

static int event_loop(ares_channel_t *channel)
{
  while (1) {
    fd_set          read_fds;
    fd_set          write_fds;
    int             nfds;
    struct timeval  tv;
    struct timeval *tvp;
    int             count;

    FD_ZERO(&read_fds);
    FD_ZERO(&write_fds);
    memset(&tv, 0, sizeof(tv));

    nfds = ares_fds(channel, &read_fds, &write_fds);
    if (nfds == 0) {
      break;
    }
    tvp = ares_timeout(channel, NULL, &tv);
    if (tvp == NULL) {
      break;
    }
    count = select(nfds, &read_fds, &write_fds, NULL, tvp);
    if (count < 0) {
#ifdef USE_WINSOCK
      int err = WSAGetLastError();
#else
      int err = errno;
#endif
      if (err != EAGAIN && err != EINTR) {
        fprintf(stderr, "select fail: %d", err);
        return 1;
      }
    }
    ares_process(channel, &read_fds, &write_fds);
  }
  return 0;
}

int main(int argc, char **argv)
{
  ares_channel_t *channel = NULL;
  ares_status_t   status;
  adig_config_t   config;
  int             i;
  int             rv = 0;

#ifdef USE_WINSOCK
  WORD    wVersionRequested = MAKEWORD(USE_WINSOCK, USE_WINSOCK);
  WSADATA wsaData;
  WSAStartup(wVersionRequested, &wsaData);
#endif

  status = (ares_status_t)ares_library_init(ARES_LIB_INIT_ALL);
  if (status != ARES_SUCCESS) {
    fprintf(stderr, "ares_library_init: %s\n", ares_strerror((int)status));
    return 1;
  }

  memset(&config, 0, sizeof(config));
  config.qclass = ARES_CLASS_IN;
  config.qtype  = ARES_REC_TYPE_A;
  if (!read_cmdline(argc, (const char **)argv, &config)) {
    printf("\n** ERROR: %s\n\n", config.error);
    print_help();
    rv = 1;
    goto done;
  }

  if (config.is_help) {
    print_help();
    goto done;
  }

  status =
    (ares_status_t)ares_init_options(&channel, &config.options, config.optmask);
  if (status != ARES_SUCCESS) {
    fprintf(stderr, "ares_init_options: %s\n", ares_strerror((int)status));
    rv = 1;
    goto done;
  }

  if (config.servers) {
    status = (ares_status_t)ares_set_servers_ports_csv(channel, config.servers);
    if (status != ARES_SUCCESS) {
      fprintf(stderr, "ares_set_servers_ports_csv: %s\n",
              ares_strerror((int)status));
      rv = 1;
      goto done;
    }
  }

  /* Enqueue a query for each separate name */
  for (i = config.args_processed; i < argc; i++) {
    status = enqueue_query(channel, &config, argv[i]);
    if (status != ARES_SUCCESS) {
      fprintf(stderr, "Failed to create query for %s: %s\n", argv[i],
              ares_strerror((int)status));
      rv = 1;
      goto done;
    }
  }

  /* Debug */
  printf("\n; <<>> c-ares DiG %s <<>>", ares_version(NULL));
  for (i = config.args_processed; i < argc; i++) {
    printf(" %s", argv[i]);
  }
  printf("\n");

  /* Process events */
  rv = event_loop(channel);

done:
  free_config(&config);
  ares_destroy(channel);
  ares_library_cleanup();

#ifdef USE_WINSOCK
  WSACleanup();
#endif
  return rv;
}