DNSPacket.h - mozsearch

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_net_DNSPacket_h__

#define mozilla_net_DNSPacket_h__

#include "mozilla/Maybe.h"

#include "mozilla/Result.h"

#include "nsClassHashtable.h"

#include "nsIDNSService.h"

#include "DNS.h"

#include "DNSByTypeRecord.h"

#include <functional>

namespace mozilla {

namespace net {

class DOHresp {

 public:

  nsresult Add(uint32_t TTL, unsigned char const* dns, unsigned int index,

               uint16_t len, bool aLocalAllowed);

  nsTArray<NetAddr> mAddresses;

  uint32_t mTtl = 0;

};

// the values map to RFC1035 type identifiers

enum TrrType {

  TRRTYPE_A = 1,

  TRRTYPE_NS = 2,

  TRRTYPE_CNAME = 5,

  TRRTYPE_AAAA = 28,

  TRRTYPE_OPT = 41,

  TRRTYPE_TXT = 16,

  TRRTYPE_HTTPSSVC = nsIDNSService::RESOLVE_TYPE_HTTPSSVC,  // 65

};

class DNSPacket {

 public:

  // Never accept larger DOH responses than this as that would indicate

  // something is wrong. Typical ones are much smaller.

  static const unsigned int MAX_SIZE = 3200;

  DNSPacket() = default;

  virtual ~DNSPacket() = default;

  Result<uint8_t, nsresult> GetRCode() const;

  Result<bool, nsresult> RecursionAvailable() const;

  // Called in order to feed data into the buffer.

  nsresult OnDataAvailable(nsIRequest* aRequest, nsIInputStream* aInputStream,

                           uint64_t aOffset, const uint32_t aCount);

  // Encode the input host name into a sequence of labels.

  static nsresult EncodeHost(nsCString& aBody, const nsACString& aHost);

  // Encodes the name request into a buffer that represents a DNS packet

  virtual nsresult EncodeRequest(nsCString& aBody, const nsACString& aHost,

                                 uint16_t aType, bool aDisableECS);

  // Decodes the DNS response and extracts the responses, additional records,

  // etc. XXX: This should probably be refactored to reduce the number of

  // output parameters and have a common format for different record types.

  virtual nsresult Decode(

      nsCString& aHost, enum TrrType aType, nsCString& aCname,

      bool aAllowRFC1918, DOHresp& aResp, TypeRecordResultType& aTypeResult,

      nsClassHashtable<nsCStringHashKey, DOHresp>& aAdditionalRecords,

      uint32_t& aTTL);

  void SetOriginHost(const Maybe<nsCString>& aHost) { mOriginHost = aHost; }

  nsresult FillBuffer(std::function<int(unsigned char response[MAX_SIZE])>&&);

  static nsresult ParseHTTPS(uint16_t aRDLen, struct SVCB& aParsed,

                             unsigned int aIndex, const unsigned char* aBuffer,

                             unsigned int aBodySize,

                             const nsACString& aOriginHost);

  void SetNativePacket(bool aNative) { mNativePacket = aNative; }

 protected:

  nsresult PassQName(unsigned int& index, const unsigned char* aBuffer);

  static nsresult GetQname(nsACString& aQname, unsigned int& aIndex,

                           const unsigned char* aBuffer,

                           unsigned int aBodySize);

  static nsresult ParseSvcParam(unsigned int svcbIndex, uint16_t key,

                                SvcFieldValue& field, uint16_t length,

                                const unsigned char* aBuffer);

  nsresult DecodeInternal(

      nsCString& aHost, enum TrrType aType, nsCString& aCname,

      bool aAllowRFC1918, DOHresp& aResp, TypeRecordResultType& aTypeResult,

      nsClassHashtable<nsCStringHashKey, DOHresp>& aAdditionalRecords,

      uint32_t& aTTL, const unsigned char* aBuffer, uint32_t aLen);

  // The response buffer.

  unsigned char mResponse[MAX_SIZE]{};

  unsigned int mBodySize = 0;

  // True when decoding a DNS packet received from OS. Decoding will

  // not panic if packet ID is not zero.

  bool mNativePacket = false;

  nsresult mStatus = NS_OK;

  Maybe<nsCString> mOriginHost;

};

}  // namespace net

}  // namespace mozilla

#endif  // mozilla_net_DNSPacket_h__