/* Copyright 1998 by the Massachusetts Institute of Technology.

 * Copyright (C) 2009 by Jakub Hrozek <jhrozek@redhat.com>

 *

 * 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.

 */

#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

#ifdef HAVE_ARPA_NAMESER_H

#  include <arpa/nameser.h>

#else

#  include "nameser.h"

#endif

#ifdef HAVE_ARPA_NAMESER_COMPAT_H

#  include <arpa/nameser_compat.h>

#endif

#include "ares.h"

#include "ares_dns.h"

#include "ares_data.h"

#include "ares_private.h"

/* AIX portability check */

#ifndef T_SRV

#  define T_SRV 33 /* server selection */

#endif

int

ares_parse_srv_reply (const unsigned char *abuf, int alen,

                      struct ares_srv_reply **srv_out)

{

  unsigned int qdcount, ancount, i;

  const unsigned char *aptr, *vptr;

  int status, rr_type, rr_class, rr_len;

  long len;

  char *hostname = NULL, *rr_name = NULL;

  struct ares_srv_reply *srv_head = NULL;

  struct ares_srv_reply *srv_last = NULL;

  struct ares_srv_reply *srv_curr;

  /* Set *srv_out to NULL for all failure cases. */

  *srv_out = NULL;

  /* Give up if abuf doesn't have room for a header. */

  if (alen < HFIXEDSZ)

    return ARES_EBADRESP;

  /* Fetch the question and answer count from the header. */

  qdcount = DNS_HEADER_QDCOUNT (abuf);

  ancount = DNS_HEADER_ANCOUNT (abuf);

  if (qdcount != 1)

    return ARES_EBADRESP;

  if (ancount == 0)

    return ARES_ENODATA;

  /* Expand the name from the question, and skip past the question. */

  aptr = abuf + HFIXEDSZ;

  status = ares_expand_name (aptr, abuf, alen, &hostname, &len;;

  if (status != ARES_SUCCESS)

    return status;

  if (aptr + len + QFIXEDSZ > abuf + alen)

    {

      ares_free (hostname);

      return ARES_EBADRESP;

    }

  aptr += len + QFIXEDSZ;

  /* Examine each answer resource record (RR) in turn. */

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

    {

      /* Decode the RR up to the data field. */

      status = ares_expand_name (aptr, abuf, alen, &rr_name, &len;;

      if (status != ARES_SUCCESS)

        {

          break;

        }

      aptr += len;

      if (aptr + RRFIXEDSZ > abuf + alen)

        {

          status = ARES_EBADRESP;

          break;

        }

      rr_type = DNS_RR_TYPE (aptr);

      rr_class = DNS_RR_CLASS (aptr);

      rr_len = DNS_RR_LEN (aptr);

      aptr += RRFIXEDSZ;

      if (aptr + rr_len > abuf + alen)

        {

          status = ARES_EBADRESP;

          break;

        }

      /* Check if we are really looking at a SRV record */

      if (rr_class == C_IN && rr_type == T_SRV)

        {

          /* parse the SRV record itself */

          if (rr_len < 6)

            {

              status = ARES_EBADRESP;

              break;

            }

          /* Allocate storage for this SRV answer appending it to the list */

          srv_curr = ares_malloc_data(ARES_DATATYPE_SRV_REPLY);

          if (!srv_curr)

            {

              status = ARES_ENOMEM;

              break;

            }

          if (srv_last)

            {

              srv_last->next = srv_curr;

            }

          else

            {

              srv_head = srv_curr;

            }

          srv_last = srv_curr;

          vptr = aptr;

          srv_curr->priority = DNS__16BIT(vptr);

          vptr += sizeof(unsigned short);

          srv_curr->weight = DNS__16BIT(vptr);

          vptr += sizeof(unsigned short);

          srv_curr->port = DNS__16BIT(vptr);

          vptr += sizeof(unsigned short);

          status = ares_expand_name (vptr, abuf, alen, &srv_curr->host, &len;;

          if (status != ARES_SUCCESS)

            break;

        }

      /* Don't lose memory in the next iteration */

      ares_free (rr_name);

      rr_name = NULL;

      /* Move on to the next record */

      aptr += rr_len;

    }

  if (hostname)

    ares_free (hostname);

  if (rr_name)

    ares_free (rr_name);

  /* clean up on error */

  if (status != ARES_SUCCESS)

    {

      if (srv_head)

        ares_free_data (srv_head);

      return status;

    }

  /* everything looks fine, return the data */

  *srv_out = srv_head;

  return ARES_SUCCESS;

}