netwerk/dns/DNSPacket.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef mozilla_net_DNSPacket_h__
   6 #define mozilla_net_DNSPacket_h__
   7
   8 #include "mozilla/Maybe.h"
   9 #include "mozilla/Result.h"
  10 #include "nsClassHashtable.h"
  11 #include "nsIDNSService.h"
  12 #include "DNS.h"
  13 #include "DNSByTypeRecord.h"
  14
  15 #include <functional>
  16
  17 namespace mozilla {
  18 namespace net {
  19
  20 class DOHresp {
  21  public:
  22   nsresult Add(uint32_t TTL, unsigned char const* dns, unsigned int index,
  23                uint16_t len, bool aLocalAllowed);
  24   nsTArray<NetAddr> mAddresses;
  25   uint32_t mTtl = 0;
  26 };
  27
  28 // the values map to RFC1035 type identifiers
  29 enum TrrType {
  30   TRRTYPE_A = 1,
  31   TRRTYPE_NS = 2,
  32   TRRTYPE_CNAME = 5,
  33   TRRTYPE_AAAA = 28,
  34   TRRTYPE_OPT = 41,
  35   TRRTYPE_TXT = 16,
  36   TRRTYPE_HTTPSSVC = nsIDNSService::RESOLVE_TYPE_HTTPSSVC,  // 65
  37 };
  38
  39 class DNSPacket {
  40  public:
  41   // Never accept larger DOH responses than this as that would indicate
  42   // something is wrong. Typical ones are much smaller.
  43   static const unsigned int MAX_SIZE = 3200;
  44
  45   DNSPacket() = default;
  46   virtual ~DNSPacket() = default;
  47
  48   Result<uint8_t, nsresult> GetRCode() const;
  49   Result<bool, nsresult> RecursionAvailable() const;
  50
  51   // Called in order to feed data into the buffer.
  52   nsresult OnDataAvailable(nsIRequest* aRequest, nsIInputStream* aInputStream,
  53                            uint64_t aOffset, const uint32_t aCount);
  54
  55   // Encode the input host name into a sequence of labels.
  56   static nsresult EncodeHost(nsCString& aBody, const nsACString& aHost);
  57   // Encodes the name request into a buffer that represents a DNS packet
  58   virtual nsresult EncodeRequest(nsCString& aBody, const nsACString& aHost,
  59                                  uint16_t aType, bool aDisableECS);
  60
  61   // Decodes the DNS response and extracts the responses, additional records,
  62   // etc. XXX: This should probably be refactored to reduce the number of
  63   // output parameters and have a common format for different record types.
  64   virtual nsresult Decode(
  65       nsCString& aHost, enum TrrType aType, nsCString& aCname,
  66       bool aAllowRFC1918, DOHresp& aResp, TypeRecordResultType& aTypeResult,
  67       nsClassHashtable<nsCStringHashKey, DOHresp>& aAdditionalRecords,
  68       uint32_t& aTTL);
  69
  70   void SetOriginHost(const Maybe<nsCString>& aHost) { mOriginHost = aHost; }
  71
  72   nsresult FillBuffer(std::function<int(unsigned char response[MAX_SIZE])>&&);
  73
  74   static nsresult ParseHTTPS(uint16_t aRDLen, struct SVCB& aParsed,
  75                              unsigned int aIndex, const unsigned char* aBuffer,
  76                              unsigned int aBodySize,
  77                              const nsACString& aOriginHost);
  78   void SetNativePacket(bool aNative) { mNativePacket = aNative; }
  79
  80   static nsresult GetQname(nsACString& aQname, unsigned int& aIndex,
  81                            const unsigned char* aBuffer,
  82                            unsigned int aBodySize);
  83
  84  protected:
  85   nsresult PassQName(unsigned int& index, const unsigned char* aBuffer);
  86   static nsresult ParseSvcParam(unsigned int svcbIndex, uint16_t key,
  87                                 SvcFieldValue& field, uint16_t length,
  88                                 const unsigned char* aBuffer);
  89   nsresult DecodeInternal(
  90       nsCString& aHost, enum TrrType aType, nsCString& aCname,
  91       bool aAllowRFC1918, DOHresp& aResp, TypeRecordResultType& aTypeResult,
  92       nsClassHashtable<nsCStringHashKey, DOHresp>& aAdditionalRecords,
  93       uint32_t& aTTL, const unsigned char* aBuffer, uint32_t aLen);
  94
  95   // The response buffer.
  96   unsigned char mResponse[MAX_SIZE]{};
  97   unsigned int mBodySize = 0;
  98   // True when decoding a DNS packet received from OS. Decoding will
  99   // not panic if packet ID is not zero.
 100   bool mNativePacket = false;
 101   nsresult mStatus = NS_OK;
 102   Maybe<nsCString> mOriginHost;
 103 };
 104
 105 }  // namespace net
 106 }  // namespace mozilla
 107
 108 #endif  // mozilla_net_DNSPacket_h__