text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2020 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <cstdint>
  #include <netaddress.h>
  #include <hash.h>
  #include <util/strencodings.h>
  #include <util/asmap.h>
  #include <tinyformat.h>
  
  static const unsigned char pchIPv4[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff };
  static const unsigned char pchOnionCat[] = {0xFD,0x87,0xD8,0x7E,0xEB,0x43};
  
  // 0xFD + sha256("bitcoin")[0:5]
  static const unsigned char g_internal_prefix[] = { 0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24 };
  
  /**
   * Construct an unspecified IPv6 network address (::/128).
   *
   * @note This address is considered invalid by CNetAddr::IsValid()
   */
  CNetAddr::CNetAddr()
  {
      memset(ip, 0, sizeof(ip));
  }
  
  void CNetAddr::SetIP(const CNetAddr& ipIn)
  {
      m_net = ipIn.m_net;
      memcpy(ip, ipIn.ip, sizeof(ip));
  }
  
  void CNetAddr::SetLegacyIPv6(const uint8_t ipv6[16])
  {
      if (memcmp(ipv6, pchIPv4, sizeof(pchIPv4)) == 0) {
          m_net = NET_IPV4;
      } else if (memcmp(ipv6, pchOnionCat, sizeof(pchOnionCat)) == 0) {
          m_net = NET_ONION;
      } else if (memcmp(ipv6, g_internal_prefix, sizeof(g_internal_prefix)) == 0) {
          m_net = NET_INTERNAL;
      } else {
          m_net = NET_IPV6;
      }
      memcpy(ip, ipv6, 16);
  }
  
  void CNetAddr::SetRaw(Network network, const uint8_t *ip_in)
  {
      switch(network)
      {
          case NET_IPV4:
              m_net = NET_IPV4;
              memcpy(ip, pchIPv4, 12);
              memcpy(ip+12, ip_in, 4);
              break;
          case NET_IPV6:
              SetLegacyIPv6(ip_in);
              break;
          default:
              assert(!"invalid network");
      }
  }
  
  /**
   * Try to make this a dummy address that maps the specified name into IPv6 like
   * so: (0xFD + %sha256("bitcoin")[0:5]) + %sha256(name)[0:10]. Such dummy
   * addresses have a prefix of fd6b:88c0:8724::/48 and are guaranteed to not be
   * publicly routable as it falls under RFC4193's fc00::/7 subnet allocated to
   * unique-local addresses.
   *
   * CAddrMan uses these fake addresses to keep track of which DNS seeds were
   * used.
   *
   * @returns Whether or not the operation was successful.
   *
   * @see CNetAddr::IsInternal(), CNetAddr::IsRFC4193()
   */
  bool CNetAddr::SetInternal(const std::string &name)
  {
      if (name.empty()) {
          return false;
      }
      m_net = NET_INTERNAL;
      unsigned char hash[32] = {};
      CSHA256().Write((const unsigned char*)name.data(), name.size()).Finalize(hash);
      memcpy(ip, g_internal_prefix, sizeof(g_internal_prefix));
      memcpy(ip + sizeof(g_internal_prefix), hash, sizeof(ip) - sizeof(g_internal_prefix));
      return true;
  }
  
  /**
   * Try to make this a dummy address that maps the specified onion address into
   * IPv6 using OnionCat's range and encoding. Such dummy addresses have a prefix
   * of fd87:d87e:eb43::/48 and are guaranteed to not be publicly routable as they
   * fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
   *
   * @returns Whether or not the operation was successful.
   *
   * @see CNetAddr::IsTor(), CNetAddr::IsRFC4193()
   */
  bool CNetAddr::SetSpecial(const std::string &strName)
  {
      if (strName.size()>6 && strName.substr(strName.size() - 6, 6) == ".onion") {
          std::vector<unsigned char> vchAddr = DecodeBase32(strName.substr(0, strName.size() - 6).c_str());
          if (vchAddr.size() != 16-sizeof(pchOnionCat))
              return false;
          m_net = NET_ONION;
          memcpy(ip, pchOnionCat, sizeof(pchOnionCat));
          for (unsigned int i=0; i<16-sizeof(pchOnionCat); i++)
              ip[i + sizeof(pchOnionCat)] = vchAddr[i];
          return true;
      }
      return false;
  }
  
  CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
  {
      SetRaw(NET_IPV4, (const uint8_t*)&ipv4Addr);
  }
  
  CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr, const uint32_t scope)
  {
      SetRaw(NET_IPV6, (const uint8_t*)&ipv6Addr);
      scopeId = scope;
  }
  
  unsigned int CNetAddr::GetByte(int n) const
  {
      return ip[15-n];
  }
  
  bool CNetAddr::IsBindAny() const
  {
      const int cmplen = IsIPv4() ? 4 : 16;
      for (int i = 0; i < cmplen; ++i) {
          if (GetByte(i)) return false;
      }
  
      return true;
  }
  
  bool CNetAddr::IsIPv4() const { return m_net == NET_IPV4; }
  
  bool CNetAddr::IsIPv6() const { return m_net == NET_IPV6; }
  
  bool CNetAddr::IsRFC1918() const
  {
      return IsIPv4() && (
          GetByte(3) == 10 ||
          (GetByte(3) == 192 && GetByte(2) == 168) ||
          (GetByte(3) == 172 && (GetByte(2) >= 16 && GetByte(2) <= 31)));
  }
  
  bool CNetAddr::IsRFC2544() const
  {
      return IsIPv4() && GetByte(3) == 198 && (GetByte(2) == 18 || GetByte(2) == 19);
  }
  
  bool CNetAddr::IsRFC3927() const
  {
      return IsIPv4() && (GetByte(3) == 169 && GetByte(2) == 254);
  }
  
  bool CNetAddr::IsRFC6598() const
  {
      return IsIPv4() && GetByte(3) == 100 && GetByte(2) >= 64 && GetByte(2) <= 127;
  }
  
  bool CNetAddr::IsRFC5737() const
  {
      return IsIPv4() && ((GetByte(3) == 192 && GetByte(2) == 0 && GetByte(1) == 2) ||
          (GetByte(3) == 198 && GetByte(2) == 51 && GetByte(1) == 100) ||
          (GetByte(3) == 203 && GetByte(2) == 0 && GetByte(1) == 113));
  }
  
  bool CNetAddr::IsRFC3849() const
  {
      return IsIPv6() && GetByte(15) == 0x20 && GetByte(14) == 0x01 &&
             GetByte(13) == 0x0D && GetByte(12) == 0xB8;
  }
  
  bool CNetAddr::IsRFC3964() const
  {
      return IsIPv6() && GetByte(15) == 0x20 && GetByte(14) == 0x02;
  }
  
  bool CNetAddr::IsRFC6052() const
  {
      static const unsigned char pchRFC6052[] = {0,0x64,0xFF,0x9B,0,0,0,0,0,0,0,0};
      return IsIPv6() && memcmp(ip, pchRFC6052, sizeof(pchRFC6052)) == 0;
  }
  
  bool CNetAddr::IsRFC4380() const
  {
      return IsIPv6() && GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0 &&
             GetByte(12) == 0;
  }
  
  bool CNetAddr::IsRFC4862() const
  {
      static const unsigned char pchRFC4862[] = {0xFE,0x80,0,0,0,0,0,0};
      return IsIPv6() && memcmp(ip, pchRFC4862, sizeof(pchRFC4862)) == 0;
  }
  
  bool CNetAddr::IsRFC4193() const
  {
      return IsIPv6() && (GetByte(15) & 0xFE) == 0xFC;
  }
  
  bool CNetAddr::IsRFC6145() const
  {
      static const unsigned char pchRFC6145[] = {0,0,0,0,0,0,0,0,0xFF,0xFF,0,0};
      return IsIPv6() && memcmp(ip, pchRFC6145, sizeof(pchRFC6145)) == 0;
  }
  
  bool CNetAddr::IsRFC4843() const
  {
      return IsIPv6() && GetByte(15) == 0x20 && GetByte(14) == 0x01 &&
             GetByte(13) == 0x00 && (GetByte(12) & 0xF0) == 0x10;
  }
  
  bool CNetAddr::IsRFC7343() const
  {
      return IsIPv6() && GetByte(15) == 0x20 && GetByte(14) == 0x01 &&
             GetByte(13) == 0x00 && (GetByte(12) & 0xF0) == 0x20;
  }
  
  bool CNetAddr::IsHeNet() const
  {
      return (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x04 && GetByte(12) == 0x70);
  }
  
  /**
   * @returns Whether or not this is a dummy address that maps an onion address
   *          into IPv6.
   *
   * @see CNetAddr::SetSpecial(const std::string &)
   */
  bool CNetAddr::IsTor() const { return m_net == NET_ONION; }
  
  bool CNetAddr::IsLocal() const
  {
      // IPv4 loopback (127.0.0.0/8 or 0.0.0.0/8)
      if (IsIPv4() && (GetByte(3) == 127 || GetByte(3) == 0))
          return true;
  
      // IPv6 loopback (::1/128)
      static const unsigned char pchLocal[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
      if (IsIPv6() && memcmp(ip, pchLocal, 16) == 0)
          return true;
  
      return false;
  }
  
  /**
   * @returns Whether or not this network address is a valid address that @a could
   *          be used to refer to an actual host.
   *
   * @note A valid address may or may not be publicly routable on the global
   *       internet. As in, the set of valid addresses is a superset of the set of
   *       publicly routable addresses.
   *
   * @see CNetAddr::IsRoutable()
   */
  bool CNetAddr::IsValid() const
  {
      // Cleanup 3-byte shifted addresses caused by garbage in size field
      // of addr messages from versions before 0.2.9 checksum.
      // Two consecutive addr messages look like this:
      // header20 vectorlen3 addr26 addr26 addr26 header20 vectorlen3 addr26 addr26 addr26...
      // so if the first length field is garbled, it reads the second batch
      // of addr misaligned by 3 bytes.
      if (IsIPv6() && memcmp(ip, pchIPv4+3, sizeof(pchIPv4)-3) == 0)
          return false;
  
      // unspecified IPv6 address (::/128)
      unsigned char ipNone6[16] = {};
      if (IsIPv6() && memcmp(ip, ipNone6, 16) == 0)
          return false;
  
      // documentation IPv6 address
      if (IsRFC3849())
          return false;
  
      if (IsInternal())
          return false;
  
      if (IsIPv4())
      {
          // INADDR_NONE
          uint32_t ipNone = INADDR_NONE;
          if (memcmp(ip+12, &ipNone, 4) == 0)
              return false;
  
          // 0
          ipNone = 0;
          if (memcmp(ip+12, &ipNone, 4) == 0)
              return false;
      }
  
      return true;
  }
  
  /**
   * @returns Whether or not this network address is publicly routable on the
   *          global internet.
   *
   * @note A routable address is always valid. As in, the set of routable addresses
   *       is a subset of the set of valid addresses.
   *
   * @see CNetAddr::IsValid()
   */
  bool CNetAddr::IsRoutable() const
  {
      return IsValid() && !(IsRFC1918() || IsRFC2544() || IsRFC3927() || IsRFC4862() || IsRFC6598() || IsRFC5737() || (IsRFC4193() && !IsTor()) || IsRFC4843() || IsRFC7343() || IsLocal() || IsInternal());
  }
  
  /**
   * @returns Whether or not this is a dummy address that maps a name into IPv6.
   *
   * @see CNetAddr::SetInternal(const std::string &)
   */
  bool CNetAddr::IsInternal() const
  {
     return m_net == NET_INTERNAL;
  }
  
  enum Network CNetAddr::GetNetwork() const
  {
      if (IsInternal())
          return NET_INTERNAL;
  
      if (!IsRoutable())
          return NET_UNROUTABLE;
  
      return m_net;
  }
  
  std::string CNetAddr::ToStringIP() const
  {
      if (IsTor())
          return EncodeBase32(&ip[6], 10) + ".onion";
      if (IsInternal())
          return EncodeBase32(ip + sizeof(g_internal_prefix), sizeof(ip) - sizeof(g_internal_prefix)) + ".internal";
      CService serv(*this, 0);
      struct sockaddr_storage sockaddr;
      socklen_t socklen = sizeof(sockaddr);
      if (serv.GetSockAddr((struct sockaddr*)&sockaddr, &socklen)) {
          char name[1025] = "";
          if (!getnameinfo((const struct sockaddr*)&sockaddr, socklen, name, sizeof(name), nullptr, 0, NI_NUMERICHOST))
              return std::string(name);
      }
      if (IsIPv4())
          return strprintf("%u.%u.%u.%u", GetByte(3), GetByte(2), GetByte(1), GetByte(0));
      else
          return strprintf("%x:%x:%x:%x:%x:%x:%x:%x",
                           GetByte(15) << 8 | GetByte(14), GetByte(13) << 8 | GetByte(12),
                           GetByte(11) << 8 | GetByte(10), GetByte(9) << 8 | GetByte(8),
                           GetByte(7) << 8 | GetByte(6), GetByte(5) << 8 | GetByte(4),
                           GetByte(3) << 8 | GetByte(2), GetByte(1) << 8 | GetByte(0));
  }
  
  std::string CNetAddr::ToString() const
  {
      return ToStringIP();
  }
  
  bool operator==(const CNetAddr& a, const CNetAddr& b)
  {
      return a.m_net == b.m_net && memcmp(a.ip, b.ip, 16) == 0;
  }
  
  bool operator<(const CNetAddr& a, const CNetAddr& b)
  {
      return a.m_net < b.m_net || (a.m_net == b.m_net && memcmp(a.ip, b.ip, 16) < 0);
  }
  
  /**
   * Try to get our IPv4 address.
   *
   * @param[out] pipv4Addr The in_addr struct to which to copy.
   *
   * @returns Whether or not the operation was successful, in particular, whether
   *          or not our address was an IPv4 address.
   *
   * @see CNetAddr::IsIPv4()
   */
  bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
  {
      if (!IsIPv4())
          return false;
      memcpy(pipv4Addr, ip+12, 4);
      return true;
  }
  
  /**
   * Try to get our IPv6 address.
   *
   * @param[out] pipv6Addr The in6_addr struct to which to copy.
   *
   * @returns Whether or not the operation was successful, in particular, whether
   *          or not our address was an IPv6 address.
   *
   * @see CNetAddr::IsIPv6()
   */
  bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
  {
      if (!IsIPv6()) {
          return false;
      }
      memcpy(pipv6Addr, ip, 16);
      return true;
  }
  
  bool CNetAddr::HasLinkedIPv4() const
  {
      return IsRoutable() && (IsIPv4() || IsRFC6145() || IsRFC6052() || IsRFC3964() || IsRFC4380());
  }
  
  uint32_t CNetAddr::GetLinkedIPv4() const
  {
      if (IsIPv4() || IsRFC6145() || IsRFC6052()) {
          // IPv4, mapped IPv4, SIIT translated IPv4: the IPv4 address is the last 4 bytes of the address
          return ReadBE32(ip + 12);
      } else if (IsRFC3964()) {
          // 6to4 tunneled IPv4: the IPv4 address is in bytes 2-6
          return ReadBE32(ip + 2);
      } else if (IsRFC4380()) {
          // Teredo tunneled IPv4: the IPv4 address is in the last 4 bytes of the address, but bitflipped
          return ~ReadBE32(ip + 12);
      }
      assert(false);
  }
  
  uint32_t CNetAddr::GetNetClass() const {
      uint32_t net_class = NET_IPV6;
      if (IsLocal()) {
          net_class = 255;
      }
      if (IsInternal()) {
          net_class = NET_INTERNAL;
      } else if (!IsRoutable()) {
          net_class = NET_UNROUTABLE;
      } else if (HasLinkedIPv4()) {
          net_class = NET_IPV4;
      } else if (IsTor()) {
          net_class = NET_ONION;
      }
      return net_class;
  }
  
  uint32_t CNetAddr::GetMappedAS(const std::vector<bool> &asmap) const {
      uint32_t net_class = GetNetClass();
      if (asmap.size() == 0 || (net_class != NET_IPV4 && net_class != NET_IPV6)) {
          return 0; // Indicates not found, safe because AS0 is reserved per RFC7607.
      }
      std::vector<bool> ip_bits(128);
      if (HasLinkedIPv4()) {
          // For lookup, treat as if it was just an IPv4 address (pchIPv4 prefix + IPv4 bits)
          for (int8_t byte_i = 0; byte_i < 12; ++byte_i) {
              for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
                  ip_bits[byte_i * 8 + bit_i] = (pchIPv4[byte_i] >> (7 - bit_i)) & 1;
              }
          }
          uint32_t ipv4 = GetLinkedIPv4();
          for (int i = 0; i < 32; ++i) {
              ip_bits[96 + i] = (ipv4 >> (31 - i)) & 1;
          }
      } else {
          // Use all 128 bits of the IPv6 address otherwise
          for (int8_t byte_i = 0; byte_i < 16; ++byte_i) {
              uint8_t cur_byte = GetByte(15 - byte_i);
              for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
                  ip_bits[byte_i * 8 + bit_i] = (cur_byte >> (7 - bit_i)) & 1;
              }
          }
      }
      uint32_t mapped_as = Interpret(asmap, ip_bits);
      return mapped_as;
  }
  
  /**
   * Get the canonical identifier of our network group
   *
   * The groups are assigned in a way where it should be costly for an attacker to
   * obtain addresses with many different group identifiers, even if it is cheap
   * to obtain addresses with the same identifier.
   *
   * @note No two connections will be attempted to addresses with the same network
   *       group.
   */
  std::vector<unsigned char> CNetAddr::GetGroup(const std::vector<bool> &asmap) const
  {
      std::vector<unsigned char> vchRet;
      uint32_t net_class = GetNetClass();
      // If non-empty asmap is supplied and the address is IPv4/IPv6,
      // return ASN to be used for bucketing.
      uint32_t asn = GetMappedAS(asmap);
      if (asn != 0) { // Either asmap was empty, or address has non-asmappable net class (e.g. TOR).
          vchRet.push_back(NET_IPV6); // IPv4 and IPv6 with same ASN should be in the same bucket
          for (int i = 0; i < 4; i++) {
              vchRet.push_back((asn >> (8 * i)) & 0xFF);
          }
          return vchRet;
      }
  
      vchRet.push_back(net_class);
      int nStartByte = 0;
      int nBits = 16;
  
      if (IsLocal()) {
          // all local addresses belong to the same group
          nBits = 0;
      } else if (IsInternal()) {
          // all internal-usage addresses get their own group
          nStartByte = sizeof(g_internal_prefix);
          nBits = (sizeof(ip) - sizeof(g_internal_prefix)) * 8;
      } else if (!IsRoutable()) {
          // all other unroutable addresses belong to the same group
          nBits = 0;
      } else if (HasLinkedIPv4()) {
          // IPv4 addresses (and mapped IPv4 addresses) use /16 groups
          uint32_t ipv4 = GetLinkedIPv4();
          vchRet.push_back((ipv4 >> 24) & 0xFF);
          vchRet.push_back((ipv4 >> 16) & 0xFF);
          return vchRet;
      } else if (IsTor()) {
          nStartByte = 6;
          nBits = 4;
      } else if (IsHeNet()) {
          // for he.net, use /36 groups
          nBits = 36;
      } else {
          // for the rest of the IPv6 network, use /32 groups
          nBits = 32;
      }
  
      // push our ip onto vchRet byte by byte...
      while (nBits >= 8)
      {
          vchRet.push_back(GetByte(15 - nStartByte));
          nStartByte++;
          nBits -= 8;
      }
      // ...for the last byte, push nBits and for the rest of the byte push 1's
      if (nBits > 0)
          vchRet.push_back(GetByte(15 - nStartByte) | ((1 << (8 - nBits)) - 1));
  
      return vchRet;
  }
  
  uint64_t CNetAddr::GetHash() const
  {
      uint256 hash = Hash(ip);
      uint64_t nRet;
      memcpy(&nRet, &hash, sizeof(nRet));
      return nRet;
  }
  
  // private extensions to enum Network, only returned by GetExtNetwork,
  // and only used in GetReachabilityFrom
  static const int NET_UNKNOWN = NET_MAX + 0;
  static const int NET_TEREDO  = NET_MAX + 1;
  int static GetExtNetwork(const CNetAddr *addr)
  {
      if (addr == nullptr)
          return NET_UNKNOWN;
      if (addr->IsRFC4380())
          return NET_TEREDO;
      return addr->GetNetwork();
  }
  
  /** Calculates a metric for how reachable (*this) is from a given partner */
  int CNetAddr::GetReachabilityFrom(const CNetAddr *paddrPartner) const
  {
      enum Reachability {
          REACH_UNREACHABLE,
          REACH_DEFAULT,
          REACH_TEREDO,
          REACH_IPV6_WEAK,
          REACH_IPV4,
          REACH_IPV6_STRONG,
          REACH_PRIVATE
      };
  
      if (!IsRoutable() || IsInternal())
          return REACH_UNREACHABLE;
  
      int ourNet = GetExtNetwork(this);
      int theirNet = GetExtNetwork(paddrPartner);
      bool fTunnel = IsRFC3964() || IsRFC6052() || IsRFC6145();
  
      switch(theirNet) {
      case NET_IPV4:
          switch(ourNet) {
          default:       return REACH_DEFAULT;
          case NET_IPV4: return REACH_IPV4;
          }
      case NET_IPV6:
          switch(ourNet) {
          default:         return REACH_DEFAULT;
          case NET_TEREDO: return REACH_TEREDO;
          case NET_IPV4:   return REACH_IPV4;
          case NET_IPV6:   return fTunnel ? REACH_IPV6_WEAK : REACH_IPV6_STRONG; // only prefer giving our IPv6 address if it's not tunnelled
          }
      case NET_ONION:
          switch(ourNet) {
          default:         return REACH_DEFAULT;
          case NET_IPV4:   return REACH_IPV4; // Tor users can connect to IPv4 as well
          case NET_ONION:    return REACH_PRIVATE;
          }
      case NET_TEREDO:
          switch(ourNet) {
          default:          return REACH_DEFAULT;
          case NET_TEREDO:  return REACH_TEREDO;
          case NET_IPV6:    return REACH_IPV6_WEAK;
          case NET_IPV4:    return REACH_IPV4;
          }
      case NET_UNKNOWN:
      case NET_UNROUTABLE:
      default:
          switch(ourNet) {
          default:          return REACH_DEFAULT;
          case NET_TEREDO:  return REACH_TEREDO;
          case NET_IPV6:    return REACH_IPV6_WEAK;
          case NET_IPV4:    return REACH_IPV4;
          case NET_ONION:     return REACH_PRIVATE; // either from Tor, or don't care about our address
          }
      }
  }
  
  CService::CService() : port(0)
  {
  }
  
  CService::CService(const CNetAddr& cip, uint16_t portIn) : CNetAddr(cip), port(portIn)
  {
  }
  
  CService::CService(const struct in_addr& ipv4Addr, uint16_t portIn) : CNetAddr(ipv4Addr), port(portIn)
  {
  }
  
  CService::CService(const struct in6_addr& ipv6Addr, uint16_t portIn) : CNetAddr(ipv6Addr), port(portIn)
  {
  }
  
  CService::CService(const struct sockaddr_in& addr) : CNetAddr(addr.sin_addr), port(ntohs(addr.sin_port))
  {
      assert(addr.sin_family == AF_INET);
  }
  
  CService::CService(const struct sockaddr_in6 &addr) : CNetAddr(addr.sin6_addr, addr.sin6_scope_id), port(ntohs(addr.sin6_port))
  {
     assert(addr.sin6_family == AF_INET6);
  }
  
  bool CService::SetSockAddr(const struct sockaddr *paddr)
  {
      switch (paddr->sa_family) {
      case AF_INET:
          *this = CService(*(const struct sockaddr_in*)paddr);
          return true;
      case AF_INET6:
          *this = CService(*(const struct sockaddr_in6*)paddr);
          return true;
      default:
          return false;
      }
  }
  
  uint16_t CService::GetPort() const
  {
      return port;
  }
  
  bool operator==(const CService& a, const CService& b)
  {
      return static_cast<CNetAddr>(a) == static_cast<CNetAddr>(b) && a.port == b.port;
  }
  
  bool operator<(const CService& a, const CService& b)
  {
      return static_cast<CNetAddr>(a) < static_cast<CNetAddr>(b) || (static_cast<CNetAddr>(a) == static_cast<CNetAddr>(b) && a.port < b.port);
  }
  
  /**
   * Obtain the IPv4/6 socket address this represents.
   *
   * @param[out] paddr The obtained socket address.
   * @param[in,out] addrlen The size, in bytes, of the address structure pointed
   *                        to by paddr. The value that's pointed to by this
   *                        parameter might change after calling this function if
   *                        the size of the corresponding address structure
   *                        changed.
   *
   * @returns Whether or not the operation was successful.
   */
  bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
  {
      if (IsIPv4()) {
          if (*addrlen < (socklen_t)sizeof(struct sockaddr_in))
              return false;
          *addrlen = sizeof(struct sockaddr_in);
          struct sockaddr_in *paddrin = (struct sockaddr_in*)paddr;
          memset(paddrin, 0, *addrlen);
          if (!GetInAddr(&paddrin->sin_addr))
              return false;
          paddrin->sin_family = AF_INET;
          paddrin->sin_port = htons(port);
          return true;
      }
      if (IsIPv6()) {
          if (*addrlen < (socklen_t)sizeof(struct sockaddr_in6))
              return false;
          *addrlen = sizeof(struct sockaddr_in6);
          struct sockaddr_in6 *paddrin6 = (struct sockaddr_in6*)paddr;
          memset(paddrin6, 0, *addrlen);
          if (!GetIn6Addr(&paddrin6->sin6_addr))
              return false;
          paddrin6->sin6_scope_id = scopeId;
          paddrin6->sin6_family = AF_INET6;
          paddrin6->sin6_port = htons(port);
          return true;
      }
      return false;
  }
  
  /**
   * @returns An identifier unique to this service's address and port number.
   */
  std::vector<unsigned char> CService::GetKey() const
  {
      auto key = GetAddrBytes();
      key.push_back(port / 0x100); // most significant byte of our port
      key.push_back(port & 0x0FF); // least significant byte of our port
      return key;
  }
  
  std::string CService::ToStringPort() const
  {
      return strprintf("%u", port);
  }
  
  std::string CService::ToStringIPPort() const
  {
      if (IsIPv4() || IsTor() || IsInternal()) {
          return ToStringIP() + ":" + ToStringPort();
      } else {
          return "[" + ToStringIP() + "]:" + ToStringPort();
      }
  }
  
  std::string CService::ToString() const
  {
      return ToStringIPPort();
  }
  
  CSubNet::CSubNet():
      valid(false)
  {
      memset(netmask, 0, sizeof(netmask));
  }
  
  CSubNet::CSubNet(const CNetAddr &addr, int32_t mask)
  {
      valid = true;
      network = addr;
      // Default to /32 (IPv4) or /128 (IPv6), i.e. match single address
      memset(netmask, 255, sizeof(netmask));
  
      // IPv4 addresses start at offset 12, and first 12 bytes must match, so just offset n
      const int astartofs = network.IsIPv4() ? 12 : 0;
  
      int32_t n = mask;
      if(n >= 0 && n <= (128 - astartofs*8)) // Only valid if in range of bits of address
      {
          n += astartofs*8;
          // Clear bits [n..127]
          for (; n < 128; ++n)
              netmask[n>>3] &= ~(1<<(7-(n&7)));
      } else
          valid = false;
  
      // Normalize network according to netmask
      for(int x=0; x<16; ++x)
          network.ip[x] &= netmask[x];
  }
  
  CSubNet::CSubNet(const CNetAddr &addr, const CNetAddr &mask)
  {
      valid = true;
      network = addr;
      // Default to /32 (IPv4) or /128 (IPv6), i.e. match single address
      memset(netmask, 255, sizeof(netmask));
  
      // IPv4 addresses start at offset 12, and first 12 bytes must match, so just offset n
      const int astartofs = network.IsIPv4() ? 12 : 0;
  
      for(int x=astartofs; x<16; ++x)
          netmask[x] = mask.ip[x];
  
      // Normalize network according to netmask
      for(int x=0; x<16; ++x)
          network.ip[x] &= netmask[x];
  }
  
  CSubNet::CSubNet(const CNetAddr &addr):
      valid(addr.IsValid())
  {
      memset(netmask, 255, sizeof(netmask));
      network = addr;
  }
  
  /**
   * @returns True if this subnet is valid, the specified address is valid, and
   *          the specified address belongs in this subnet.
   */
  bool CSubNet::Match(const CNetAddr &addr) const
  {
      if (!valid || !addr.IsValid() || network.m_net != addr.m_net)
          return false;
      for(int x=0; x<16; ++x)
          if ((addr.ip[x] & netmask[x]) != network.ip[x])
              return false;
      return true;
  }
  
  /**
   * @returns The number of 1-bits in the prefix of the specified subnet mask. If
   *          the specified subnet mask is not a valid one, -1.
   */
  static inline int NetmaskBits(uint8_t x)
  {
      switch(x) {
      case 0x00: return 0;
      case 0x80: return 1;
      case 0xc0: return 2;
      case 0xe0: return 3;
      case 0xf0: return 4;
      case 0xf8: return 5;
      case 0xfc: return 6;
      case 0xfe: return 7;
      case 0xff: return 8;
      default: return -1;
      }
  }
  
  std::string CSubNet::ToString() const
  {
      /* Parse binary 1{n}0{N-n} to see if mask can be represented as /n */
      int cidr = 0;
      bool valid_cidr = true;
      int n = network.IsIPv4() ? 12 : 0;
      for (; n < 16 && netmask[n] == 0xff; ++n)
          cidr += 8;
      if (n < 16) {
          int bits = NetmaskBits(netmask[n]);
          if (bits < 0)
              valid_cidr = false;
          else
              cidr += bits;
          ++n;
      }
      for (; n < 16 && valid_cidr; ++n)
          if (netmask[n] != 0x00)
              valid_cidr = false;
  
      /* Format output */
      std::string strNetmask;
      if (valid_cidr) {
          strNetmask = strprintf("%u", cidr);
      } else {
          if (network.IsIPv4())
              strNetmask = strprintf("%u.%u.%u.%u", netmask[12], netmask[13], netmask[14], netmask[15]);
          else
              strNetmask = strprintf("%x:%x:%x:%x:%x:%x:%x:%x",
                               netmask[0] << 8 | netmask[1], netmask[2] << 8 | netmask[3],
                               netmask[4] << 8 | netmask[5], netmask[6] << 8 | netmask[7],
                               netmask[8] << 8 | netmask[9], netmask[10] << 8 | netmask[11],
                               netmask[12] << 8 | netmask[13], netmask[14] << 8 | netmask[15]);
      }
  
      return network.ToString() + "/" + strNetmask;
  }
  
  bool CSubNet::IsValid() const
  {
      return valid;
  }
  
  bool operator==(const CSubNet& a, const CSubNet& b)
  {
      return a.valid == b.valid && a.network == b.network && !memcmp(a.netmask, b.netmask, 16);
  }
  
  bool operator<(const CSubNet& a, const CSubNet& b)
  {
      return (a.network < b.network || (a.network == b.network && memcmp(a.netmask, b.netmask, 16) < 0));
  }
  
  bool SanityCheckASMap(const std::vector<bool>& asmap)
  {
      return SanityCheckASMap(asmap, 128); // For IP address lookups, the input is 128 bits
  }
  