/*

 * This file is part of PowerDNS or dnsdist.

 * Copyright -- PowerDNS.COM B.V. and its contributors

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 *

 * In addition, for the avoidance of any doubt, permission is granted to

 * link this program with OpenSSL and to (re)distribute the binaries

 * produced as the result of such linking.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "ednssubnet.hh"

#include "dns.hh"

namespace {

        struct EDNSSubnetOptsWire

        {

                uint16_t family;

                uint8_t sourceMask;

                uint8_t scopeMask;

        } GCCPACKATTRIBUTE;  // BRRRRR

}

bool getEDNSSubnetOptsFromString(const string& options, EDNSSubnetOpts* eso)

{

  //cerr<<"options.size:"<<options.size()<<endl;

  return getEDNSSubnetOptsFromString(options.c_str(), options.length(), eso);

}

bool getEDNSSubnetOptsFromString(const char* options, unsigned int len, EDNSSubnetOpts* eso)

{

  EDNSSubnetOptsWire esow;

  static_assert (sizeof(esow) == 4, "sizeof(EDNSSubnetOptsWire) must be 4 bytes");

  if(len < sizeof(esow))

    return false;

  memcpy(&esow, options, sizeof(esow));

  esow.family = ntohs(esow.family);

  //cerr<<"Family when parsing from string: "<<esow.family<<endl;

  ComboAddress address;

  unsigned int octetsin = esow.sourceMask > 0 ? (((esow.sourceMask - 1)>> 3)+1) : 0;

  //cerr<<"octetsin:"<<octetsin<<endl;

  if(esow.family == 1) {

    if(len != sizeof(esow)+octetsin)

      return false;

    if(octetsin > sizeof(address.sin4.sin_addr.s_addr))

      return false;

    address.reset();

    address.sin4.sin_family = AF_INET;

    if(octetsin > 0)

      memcpy(&address.sin4.sin_addr.s_addr, options+sizeof(esow), octetsin);

  } else if(esow.family == 2) {

    if(len != sizeof(esow)+octetsin)

      return false;

    if(octetsin > sizeof(address.sin6.sin6_addr.s6_addr))

      return false;

    address.reset();

    address.sin4.sin_family = AF_INET6;

    if(octetsin > 0)

      memcpy(&address.sin6.sin6_addr.s6_addr, options+sizeof(esow), octetsin);

  }

  else

    return false;

  //cerr<<"Source address: "<<address.toString()<<", mask: "<<(int)esow.sourceMask<<endl;

  eso->source = Netmask(address, esow.sourceMask);

  /* 'address' has more bits set (potentially) than scopeMask. This leads to odd looking netmasks that promise

     more precision than they have. For this reason we truncate the address to scopeMask bits */

  address.truncate(esow.scopeMask); // truncate will not throw for odd scopeMasks

  eso->scope = Netmask(address, esow.scopeMask);

  return true;

}

string makeEDNSSubnetOptsString(const EDNSSubnetOpts& eso)

{

  string ret;

  EDNSSubnetOptsWire esow;

  uint16_t family = htons(eso.source.getNetwork().sin4.sin_family == AF_INET ? 1 : 2);

  esow.family = family;

  esow.sourceMask = eso.source.getBits();

  esow.scopeMask = eso.scope.getBits();

  ret.assign((const char*)&esow, sizeof(esow));

  int octetsout = ((esow.sourceMask - 1)>> 3)+1;

  ComboAddress src=eso.source.getNetwork();

  src.truncate(esow.sourceMask);

  if(family == htons(1)) 

    ret.append((const char*) &src.sin4.sin_addr.s_addr, octetsout);

  else

    ret.append((const char*) &src.sin6.sin6_addr.s6_addr, octetsout);

  return ret;

}