text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2015 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifdef HAVE_CONFIG_H
  #include "config/gobyte-config.h"
  #endif
  
  #include "netaddress.h"
  #include "hash.h"
  #include "utilstrencodings.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};
  
  void CNetAddr::Init()
  {
      memset(ip, 0, sizeof(ip));
  }
  
  void CNetAddr::SetIP(const CNetAddr& ipIn)
  {
      memcpy(ip, ipIn.ip, sizeof(ip));
  }
  
  void CNetAddr::SetRaw(Network network, const uint8_t *ip_in)
  {
      switch(network)
      {
          case NET_IPV4:
              memcpy(ip, pchIPv4, 12);
              memcpy(ip+12, ip_in, 4);
              break;
          case NET_IPV6:
              memcpy(ip, ip_in, 16);
              break;
          default:
              assert(!"invalid network");
      }
  }
  
  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;
          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()
  {
      Init();
  }
  
  CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
  {
      SetRaw(NET_IPV4, (const uint8_t*)&ipv4Addr);
  }
  
  CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr)
  {
      SetRaw(NET_IPV6, (const uint8_t*)&ipv6Addr);
  }
  
  unsigned int CNetAddr::GetByte(int n) const
  {
      return ip[15-n];
  }
  
  bool CNetAddr::IsIPv4() const
  {
      return (memcmp(ip, pchIPv4, sizeof(pchIPv4)) == 0);
  }
  
  bool CNetAddr::IsIPv6() const
  {
      return (!IsIPv4() && !IsTor());
  }
  
  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 GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x0D && GetByte(12) == 0xB8;
  }
  
  bool CNetAddr::IsRFC3964() const
  {
      return (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 (memcmp(ip, pchRFC6052, sizeof(pchRFC6052)) == 0);
  }
  
  bool CNetAddr::IsRFC4380() const
  {
      return (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 (memcmp(ip, pchRFC4862, sizeof(pchRFC4862)) == 0);
  }
  
  bool CNetAddr::IsRFC4193() const
  {
      return ((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 (memcmp(ip, pchRFC6145, sizeof(pchRFC6145)) == 0);
  }
  
  bool CNetAddr::IsRFC4843() const
  {
      return (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x00 && (GetByte(12) & 0xF0) == 0x10);
  }
  
  bool CNetAddr::IsTor() const
  {
      return (memcmp(ip, pchOnionCat, sizeof(pchOnionCat)) == 0);
  }
  
  bool CNetAddr::IsLocal() const
  {
      // IPv4 loopback
     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 (memcmp(ip, pchLocal, 16) == 0)
         return true;
  
     return false;
  }
  
  bool CNetAddr::IsMulticast() const
  {
      return    (IsIPv4() && (GetByte(3) & 0xF0) == 0xE0)
             || (GetByte(15) == 0xFF);
  }
  
  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 (memcmp(ip, pchIPv4+3, sizeof(pchIPv4)-3) == 0)
          return false;
  
      // unspecified IPv6 address (::/128)
      unsigned char ipNone[16] = {};
      if (memcmp(ip, ipNone, 16) == 0)
          return false;
  
      // documentation IPv6 address
      if (IsRFC3849())
          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;
  }
  
  bool CNetAddr::IsRoutable() const
  {
      return IsValid() && !(IsRFC1918() || IsRFC2544() || IsRFC3927() || IsRFC4862() || IsRFC6598() || IsRFC5737() || (IsRFC4193() && !IsTor()) || IsRFC4843() || IsLocal());
  }
  
  enum Network CNetAddr::GetNetwork() const
  {
      if (!IsRoutable())
          return NET_UNROUTABLE;
  
      if (IsIPv4())
          return NET_IPV4;
  
      if (IsTor())
          return NET_TOR;
  
      return NET_IPV6;
  }
  
  std::string CNetAddr::ToStringIP(bool fUseGetnameinfo) const
  {
      if (IsTor())
          return EncodeBase32(&ip[6], 10) + ".onion";
      if (fUseGetnameinfo)
      {
          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), NULL, 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 (memcmp(a.ip, b.ip, 16) == 0);
  }
  
  bool operator!=(const CNetAddr& a, const CNetAddr& b)
  {
      return (memcmp(a.ip, b.ip, 16) != 0);
  }
  
  bool operator<(const CNetAddr& a, const CNetAddr& b)
  {
      return (memcmp(a.ip, b.ip, 16) < 0);
  }
  
  bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
  {
      if (!IsIPv4())
          return false;
      memcpy(pipv4Addr, ip+12, 4);
      return true;
  }
  
  bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
  {
      memcpy(pipv6Addr, ip, 16);
      return true;
  }
  
  // get canonical identifier of an address' group
  // no two connections will be attempted to addresses with the same group
  std::vector<unsigned char> CNetAddr::GetGroup() const
  {
      std::vector<unsigned char> vchRet;
      int nClass = NET_IPV6;
      int nStartByte = 0;
      int nBits = 16;
  
      // all local addresses belong to the same group
      if (IsLocal())
      {
          nClass = 255;
          nBits = 0;
      }
  
      // all unroutable addresses belong to the same group
      if (!IsRoutable())
      {
          nClass = NET_UNROUTABLE;
          nBits = 0;
      }
      // for IPv4 addresses, '1' + the 16 higher-order bits of the IP
      // includes mapped IPv4, SIIT translated IPv4, and the well-known prefix
      else if (IsIPv4() || IsRFC6145() || IsRFC6052())
      {
          nClass = NET_IPV4;
          nStartByte = 12;
      }
      // for 6to4 tunnelled addresses, use the encapsulated IPv4 address
      else if (IsRFC3964())
      {
          nClass = NET_IPV4;
          nStartByte = 2;
      }
      // for Teredo-tunnelled IPv6 addresses, use the encapsulated IPv4 address
      else if (IsRFC4380())
      {
          vchRet.push_back(NET_IPV4);
          vchRet.push_back(GetByte(3) ^ 0xFF);
          vchRet.push_back(GetByte(2) ^ 0xFF);
          return vchRet;
      }
      else if (IsTor())
      {
          nClass = NET_TOR;
          nStartByte = 6;
          nBits = 4;
      }
      // for he.net, use /36 groups
      else if (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x04 && GetByte(12) == 0x70)
          nBits = 36;
      // for the rest of the IPv6 network, use /32 groups
      else
          nBits = 32;
  
      vchRet.push_back(nClass);
      while (nBits >= 8)
      {
          vchRet.push_back(GetByte(15 - nStartByte));
          nStartByte++;
          nBits -= 8;
      }
      if (nBits > 0)
          vchRet.push_back(GetByte(15 - nStartByte) | ((1 << (8 - nBits)) - 1));
  
      return vchRet;
  }
  
  uint64_t CNetAddr::GetHash() const
  {
      uint256 hash = Hash(&ip[0], &ip[16]);
      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 == NULL)
          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())
          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_TOR:
          switch(ourNet) {
          default:         return REACH_DEFAULT;
          case NET_IPV4:   return REACH_IPV4; // Tor users can connect to IPv4 as well
          case NET_TOR:    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_TOR:     return REACH_PRIVATE; // either from Tor, or don't care about our address
          }
      }
  }
  
  void CService::Init()
  {
      port = 0;
  }
  
  CService::CService()
  {
      Init();
  }
  
  CService::CService(const CNetAddr& cip, unsigned short portIn) : CNetAddr(cip), port(portIn)
  {
  }
  
  CService::CService(const struct in_addr& ipv4Addr, unsigned short portIn) : CNetAddr(ipv4Addr), port(portIn)
  {
  }
  
  CService::CService(const struct in6_addr& ipv6Addr, unsigned short 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), 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;
      }
  }
  
  unsigned short CService::GetPort() const
  {
      return port;
  }
  
  bool operator==(const CService& a, const CService& b)
  {
      return (CNetAddr)a == (CNetAddr)b && a.port == b.port;
  }
  
  bool operator!=(const CService& a, const CService& b)
  {
      return (CNetAddr)a != (CNetAddr)b || a.port != b.port;
  }
  
  bool operator<(const CService& a, const CService& b)
  {
      return (CNetAddr)a < (CNetAddr)b || ((CNetAddr)a == (CNetAddr)b && a.port < b.port);
  }
  
  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_family = AF_INET6;
          paddrin6->sin6_port = htons(port);
          return true;
      }
      return false;
  }
  
  std::vector<unsigned char> CService::GetKey() const
  {
       std::vector<unsigned char> vKey;
       vKey.resize(18);
       memcpy(&vKey[0], ip, 16);
       vKey[16] = port / 0x100;
       vKey[17] = port & 0x0FF;
       return vKey;
  }
  
  std::string CService::ToStringPort() const
  {
      return strprintf("%u", port);
  }
  
  std::string CService::ToStringIPPort(bool fUseGetnameinfo) const
  {
      if (IsIPv4() || IsTor()) {
          return ToStringIP(fUseGetnameinfo) + ":" + ToStringPort();
      } else {
          return "[" + ToStringIP(fUseGetnameinfo) + "]:" + ToStringPort();
      }
  }
  
  std::string CService::ToString(bool fUseGetnameinfo) const
  {
      return ToStringIPPort(fUseGetnameinfo);
  }
  
  void CService::SetPort(unsigned short portIn)
  {
      port = portIn;
  }
  
  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;
  }
  
  bool CSubNet::Match(const CNetAddr &addr) const
  {
      if (!valid || !addr.IsValid())
          return false;
      for(int x=0; x<16; ++x)
          if ((addr.ip[x] & netmask[x]) != network.ip[x])
              return false;
      return true;
  }
  
  static inline int NetmaskBits(uint8_t x)
  {
      switch(x) {
      case 0x00: return 0; break;
      case 0x80: return 1; break;
      case 0xc0: return 2; break;
      case 0xe0: return 3; break;
      case 0xf0: return 4; break;
      case 0xf8: return 5; break;
      case 0xfc: return 6; break;
      case 0xfe: return 7; break;
      case 0xff: return 8; break;
      default: return -1; break;
      }
  }
  
  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==b);
  }
  
  bool operator<(const CSubNet& a, const CSubNet& b)
  {
      return (a.network < b.network || (a.network == b.network && memcmp(a.netmask, b.netmask, 16) < 0));
  }
  