lokinet/llarp/net/ip_range.hpp

#pragma once

#include "ip.hpp"
#include "net_bits.hpp"
#include <llarp/util/bits.hpp>
#include <llarp/util/buffer.hpp>
#include <llarp/util/types.hpp>

#include <list>
#include <optional>
#include <string>

namespace llarp
{
  struct IPRange
  {
    using Addr_t = huint128_t;
    huint128_t addr = {0};
    huint128_t netmask_bits = {0};

    constexpr IPRange()
    {}
    constexpr IPRange(huint128_t address, huint128_t netmask)
        : addr{std::move(address)}, netmask_bits{std::move(netmask)}
    {}

    static constexpr IPRange
    V4MappedRange()
    {
      return IPRange{huint128_t{0x0000'ffff'0000'0000UL}, netmask_ipv6_bits(96)};
    }

    static constexpr IPRange
    FromIPv4(byte_t a, byte_t b, byte_t c, byte_t d, byte_t mask)
    {
      return IPRange{net::ExpandV4(ipaddr_ipv4_bits(a, b, c, d)), netmask_ipv6_bits(mask + 96)};
    }

    static inline IPRange
    FromIPv4(net::ipv4addr_t addr, net::ipv4addr_t netmask)
    {
      return IPRange{
          net::ExpandV4(ToHost(addr)), netmask_ipv6_bits(bits::count_bits(netmask) + 96)};
    }

    /// return true if this iprange is in the IPv4 mapping range for containing ipv4 addresses
    constexpr bool
    IsV4() const
    {
      return V4MappedRange().Contains(addr);
    }

    /// get address family
    constexpr int
    Family() const
    {
      if (IsV4())
        return AF_INET;
      return AF_INET6;
    }

    /// return the number of bits set in the hostmask
    constexpr int
    HostmaskBits() const
    {
      if (IsV4())
      {
        return bits::count_bits(net::TruncateV6(netmask_bits));
      }
      return bits::count_bits(netmask_bits);
    }

    /// return true if our range and other intersect
    constexpr bool
    operator*(const IPRange& other) const
    {
      return Contains(other) or other.Contains(*this);
    }

    /// return true if the other range is inside our range
    constexpr bool
    Contains(const IPRange& other) const
    {
      return Contains(other.addr) and Contains(other.HighestAddr());
    }

    /// return true if ip is contained in this ip range
    constexpr bool
    Contains(const Addr_t& ip) const
    {
      return (addr & netmask_bits) == (ip & netmask_bits);
    }

    /// return true if we are a ipv4 range and contains this ip
    constexpr bool
    Contains(const huint32_t& ip) const
    {
      if (not IsV4())
        return false;
      return Contains(net::ExpandV4(ip));
    }

    inline bool
    Contains(const net::ipaddr_t& ip) const
    {
      return var::visit([this](auto&& ip) { return Contains(ToHost(ip)); }, ip);
    }

    /// get the highest address on this range
    constexpr huint128_t
    HighestAddr() const
    {
      return (addr & netmask_bits) + (huint128_t{1} << (128 - bits::count_bits_128(netmask_bits.h)))
          - huint128_t{1};
    }

    bool
    operator<(const IPRange& other) const
    {
      auto maskedA = addr & netmask_bits, maskedB = other.addr & other.netmask_bits;
      return std::tie(maskedA, netmask_bits) < std::tie(maskedB, other.netmask_bits);
    }

    bool
    operator==(const IPRange& other) const
    {
      return addr == other.addr and netmask_bits == other.netmask_bits;
    }

    std::string
    ToString() const
    {
      return BaseAddressString() + "/" + std::to_string(HostmaskBits());
    }

    std::string
    BaseAddressString() const;

    std::string
    NetmaskString() const;

    bool
    FromString(std::string str);

    bool
    BEncode(llarp_buffer_t* buf) const;

    bool
    BDecode(llarp_buffer_t* buf);

    /// Finds a free private use range not overlapping the given ranges.
    static std::optional<IPRange>
    FindPrivateRange(const std::list<IPRange>& excluding);
  };

  template <>
  constexpr inline bool IsToStringFormattable<IPRange> = true;

}  // namespace llarp

namespace std
{
  template <>
  struct hash<llarp::IPRange>
  {
    size_t
    operator()(const llarp::IPRange& range) const
    {
      const auto str = range.ToString();
      return std::hash<std::string>{}(str);
    }
  };
}  // namespace std