/* Copyright (C) 2019 by Andrew Selivanov

 *

 * Permission to use, copy, modify, and distribute this

 * software and its documentation for any purpose and without

 * fee is hereby granted, provided that the above copyright

 * notice appear in all copies and that both that copyright

 * notice and this permission notice appear in supporting

 * documentation, and that the name of M.I.T. not be used in

 * advertising or publicity pertaining to distribution of the

 * software without specific, written prior permission.

 * M.I.T. makes no representations about the suitability of

 * this software for any purpose.  It is provided "as is"

 * without express or implied warranty.

 *

 * SPDX-License-Identifier: MIT

 */

#include "ares_setup.h"

#ifdef HAVE_NETINET_IN_H

#  include <netinet/in.h>

#endif

#ifdef HAVE_NETDB_H

#  include <netdb.h>

#endif

#ifdef HAVE_ARPA_INET_H

#  include <arpa/inet.h>

#endif

#include "ares.h"

#include "ares_inet_net_pton.h"

#include "ares_nowarn.h"

#include "ares_private.h"

#define MAX_ALIASES 40

int ares__readaddrinfo(FILE *fp,

                       const char *name,

                       unsigned short port,

                       const struct ares_addrinfo_hints *hints,

                       struct ares_addrinfo *ai)

{

  char *line = NULL, *p, *q;

  char *txtaddr, *txthost, *txtalias;

  char *aliases[MAX_ALIASES];

  unsigned int i, alias_count;

  int status = ARES_SUCCESS;

  size_t linesize;

  struct ares_addrinfo_cname *cname = NULL, *cnames = NULL;

  struct ares_addrinfo_node *nodes = NULL;

  int match_with_alias, match_with_canonical;

  int want_cname = hints->ai_flags & ARES_AI_CANONNAME;

  /* Validate family */

  switch (hints->ai_family) {

    case AF_INET:

    case AF_INET6:

    case AF_UNSPEC:

      break;

    default:

      return ARES_EBADFAMILY;

  }

  ai->name = ares_strdup(name);

  if(!ai->name)

    {

      status = ARES_ENOMEM;

      goto fail;

    }

  while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)

    {

      match_with_alias = 0;

      match_with_canonical = 0;

      alias_count = 0;

      /* Trim line comment. */

      p = line;

      while (*p && (*p != '#'))

        p++;

      *p = '\0';

      /* Trim trailing whitespace. */

      q = p - 1;

      while ((q >= line) && ISSPACE(*q))

        q--;

      *++q = '\0';

      /* Skip leading whitespace. */

      p = line;

      while (*p && ISSPACE(*p))

        p++;

      if (!*p)

        /* Ignore line if empty. */

        continue;

      /* Pointer to start of IPv4 or IPv6 address part. */

      txtaddr = p;

      /* Advance past address part. */

      while (*p && !ISSPACE(*p))

        p++;

      if (!*p)

        /* Ignore line if reached end of line. */

        continue;

      /* Null terminate address part. */

      *p = '\0';

      /* Advance to host name */

      p++;

      while (*p && ISSPACE(*p))

        p++;

      if (!*p)

        /* Ignore line if reached end of line. */

        continue;  /* LCOV_EXCL_LINE: trailing whitespace already stripped */

      /* Pointer to start of host name. */

      txthost = p;

      /* Advance past host name. */

      while (*p && !ISSPACE(*p))

        p++;

      /* Pointer to start of first alias. */

      txtalias = NULL;

      if (*p)

        {

          q = p + 1;

          while (*q && ISSPACE(*q))

            q++;

          if (*q)

            txtalias = q;

        }

      /* Null terminate host name. */

      *p = '\0';

      /* Find out if host name matches with canonical host name. */

      if (strcasecmp(txthost, name) == 0)

        {

          match_with_canonical = 1;

        }

      /* Find out if host name matches with one of the aliases. */

      while (txtalias)

        {

          p = txtalias;

          while (*p && !ISSPACE(*p))

            p++;

          q = p;

          while (*q && ISSPACE(*q))

            q++;

          *p = '\0';

          if (strcasecmp(txtalias, name) == 0)

            {

              match_with_alias = 1;

              if (!want_cname)

                break;

            }

          if (alias_count < MAX_ALIASES)

            {

              aliases[alias_count++] = txtalias;

            }

          txtalias = *q ? q : NULL;

        }

      /* Try next line if host does not match. */

      if (!match_with_alias && !match_with_canonical)

        {

          continue;

        }

      /*

       * Convert address string to network address for the requested families.

       * Actual address family possible values are AF_INET and AF_INET6 only.

       */

      if ((hints->ai_family == AF_INET) || (hints->ai_family == AF_UNSPEC))

        {

          struct in_addr addr4;

          if (ares_inet_pton(AF_INET, txtaddr, &addr4) == 1)

            {

              status = ares_append_ai_node(AF_INET, port, 0, &addr4, &nodes);

              if (status != ARES_SUCCESS)

                {

                  goto fail;

                }

            }

        }

      if ((hints->ai_family == AF_INET6) || (hints->ai_family == AF_UNSPEC))

        {

          struct ares_in6_addr addr6;

          if (ares_inet_pton(AF_INET6, txtaddr, &addr6) == 1)

            {

              status = ares_append_ai_node(AF_INET6, port, 0, &addr6, &nodes);

              if (status != ARES_SUCCESS)

                {

                  goto fail;

                }

            }

        }

      if (want_cname)

        {

          for (i = 0; i < alias_count; ++i)

            {

              cname = ares__append_addrinfo_cname(&cnames);

              if (!cname)

                {

                  status = ARES_ENOMEM;

                  goto fail;

                }

              cname->alias = ares_strdup(aliases[i]);

              cname->name = ares_strdup(txthost);

            }

          /* No aliases, cname only. */

          if(!alias_count)

            {

              cname = ares__append_addrinfo_cname(&cnames);

              if (!cname)

                {

                  status = ARES_ENOMEM;

                  goto fail;

                }

              cname->name = ares_strdup(txthost);

            }

        }

    }

  /* Last read failed. */

  if (status == ARES_ENOMEM)

    {

      goto fail;

    }

  /* If no results, its a failure */

  if (!nodes)

    {

      status = ARES_ENOTFOUND;

      goto fail;

    }

  /* Free line buffer. */

  ares_free(line);

  ares__addrinfo_cat_cnames(&ai->cnames, cnames);

  ares__addrinfo_cat_nodes(&ai->nodes, nodes);

  return ARES_SUCCESS;

fail:

  ares_free(line);

  ares__freeaddrinfo_cnames(cnames);

  ares__freeaddrinfo_nodes(nodes);

  ares_free(ai->name);

  ai->name = NULL;

  return status;

}