/*

 * 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.

 */

#pragma once

#include <memory>

#include <string>

#include <unordered_map>

#include "config.h"

#include "noinitvector.hh"

#ifdef HAVE_DNS_OVER_HTTP3

#include "channel.hh"

#include "dolog.hh"

#include "iputils.hh"

#include "libssl.hh"

#include "stat_t.hh"

struct DOH3ServerConfig;

struct DownstreamState;

#endif

namespace dnsdist::doh3

{

using h3_headers_t = std::unordered_map<std::string, std::string>;

}

#ifdef HAVE_DNS_OVER_HTTP3

#include "dnsdist-idstate.hh"

#include "doq-common.hh"

struct DOH3Frontend

{

  DOH3Frontend();

  DOH3Frontend(const DOH3Frontend&) = delete;

  DOH3Frontend(DOH3Frontend&&) = delete;

  DOH3Frontend& operator=(const DOH3Frontend&) = delete;

  DOH3Frontend& operator=(DOH3Frontend&&) = delete;

  ~DOH3Frontend();

  void setup();

  void reloadCertificates();

  const Logr::Logger& getLogger()

  {

    return *d_logger;

  }

  std::shared_ptr<const Logr::Logger> d_logger{nullptr};

  std::unique_ptr<DOH3ServerConfig> d_server_config;

  ComboAddress d_local;

#ifdef __linux__

  // On Linux this gives us 128k pending queries (default is 8192 queries),

  // which should be enough to deal with huge spikes

  uint32_t d_internalPipeBufferSize{1024 * 1024};

#else

  uint32_t d_internalPipeBufferSize{0};

#endif

  dnsdist::doq::QuicheParams d_quicheParams;

  pdns::stat_t d_doh3UnsupportedVersionErrors{0}; // Unsupported protocol version errors

  pdns::stat_t d_doh3InvalidTokensReceived{0}; // Discarded received tokens

  pdns::stat_t d_validResponses{0}; // Valid responses sent

  pdns::stat_t d_errorResponses{0}; // Empty responses (no backend, drops, invalid queries, etc.)

};

struct DOH3Unit

{

  DOH3Unit(PacketBuffer&& query_) :

    query(std::move(query_))

  {

  }

  DOH3Unit(const DOH3Unit&) = delete;

  DOH3Unit& operator=(const DOH3Unit&) = delete;

  [[nodiscard]] std::string getHTTPPath() const;

  [[nodiscard]] std::string getHTTPQueryString() const;

  [[nodiscard]] std::string getHTTPHost() const;

  [[nodiscard]] std::string getHTTPScheme() const;

  [[nodiscard]] const dnsdist::doh3::h3_headers_t& getHTTPHeaders() const;

  void setHTTPResponse(uint16_t statusCode, PacketBuffer&& body, const std::string& contentType = "");

  InternalQueryState ids;

  PacketBuffer query;

  PacketBuffer response;

  PacketBuffer serverConnID;

  dnsdist::doh3::h3_headers_t headers;

  std::shared_ptr<DownstreamState> downstream{nullptr};

  std::shared_ptr<const std::string> sni{nullptr};

  std::string d_contentTypeOut;

  DOH3ServerConfig* dsc{nullptr};

  uint64_t streamID{0};

  size_t proxyProtocolPayloadSize{0};

  uint16_t status_code{200};

  /* whether the query was re-sent to the backend over

     TCP after receiving a truncated answer over UDP */

  bool tcp{false};

};

using DOH3UnitUniquePtr = std::unique_ptr<DOH3Unit>;

struct CrossProtocolQuery;

struct DNSQuestion;

std::unique_ptr<CrossProtocolQuery> getDOH3CrossProtocolQueryFromDQ(DNSQuestion& dnsQuestion, bool isResponse);

void doh3Thread(ClientState* clientState);

#else

struct DOH3Unit

{

  [[nodiscard]] std::string getHTTPPath() const;

  [[nodiscard]] std::string getHTTPQueryString() const;

  [[nodiscard]] std::string getHTTPHost() const;

  [[nodiscard]] std::string getHTTPScheme() const;

  [[nodiscard]] const dnsdist::doh3::h3_headers_t& getHTTPHeaders() const;

  void setHTTPResponse(uint16_t, PacketBuffer&&, const std::string&);

};

struct DOH3Frontend

{

  DOH3Frontend() = default;

  void setup()

  {

  }

};

#endif