IPAddress.h

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/*
 * Copyright 2014-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <functional>
#include <iosfwd>
#include <memory>
#include <string>
#include <utility> // std::pair

#include <folly/IPAddressException.h>
#include <folly/IPAddressV4.h>
#include <folly/IPAddressV6.h>
#include <folly/Range.h>
#include <folly/detail/IPAddress.h>

namespace folly {

class IPAddress;

typedef std::pair<IPAddress, uint8_t> CIDRNetwork;

class IPAddress {
 private:
  template <typename F>
  auto pick(F f) const {
    return isV4() ? f(asV4()) : f(asV6());
  }

 public:
  // returns true iff the input string can be parsed as an ip-address
  static bool validate(StringPiece ip) noexcept;

  // return the V4 representation of the address, converting it from V6 to V4 if
  // needed. Note that this will throw an IPAddressFormatException if the V6
  // address is not IPv4Mapped.
  static IPAddressV4 createIPv4(const IPAddress& addr);

  // return the V6 representation of the address, converting it from V4 to V6 if
  // needed.
  static IPAddressV6 createIPv6(const IPAddress& addr);

  static Expected<CIDRNetwork, CIDRNetworkError> tryCreateNetwork(
      StringPiece ipSlashCidr,
      int defaultCidr = -1,
      bool mask = true);

  static CIDRNetwork createNetwork(
      StringPiece ipSlashCidr,
      int defaultCidr = -1,
      bool mask = true);

  static std::string networkToString(const CIDRNetwork& network);

  static IPAddress fromBinary(ByteRange bytes);

  static Expected<IPAddress, IPAddressFormatError> tryFromBinary(
      ByteRange bytes) noexcept;

  static Expected<IPAddress, IPAddressFormatError> tryFromString(
      StringPiece str) noexcept;

  static IPAddress fromLong(uint32_t src);
  // Same as above, but host byte order
  static IPAddress fromLongHBO(uint32_t src);

  // Given 2 IPAddress,mask pairs extract the longest common IPAddress,
  // mask pair
  static CIDRNetwork longestCommonPrefix(
      const CIDRNetwork& one,
      const CIDRNetwork& two);

  IPAddress();

  explicit IPAddress(StringPiece ip);

  explicit IPAddress(const sockaddr* addr);

  // Create an IPAddress from a V4 address
  /* implicit */ IPAddress(const IPAddressV4 ipV4Addr) noexcept;
  /* implicit */ IPAddress(const in_addr addr) noexcept;

  // Create an IPAddress from a V6 address
  /* implicit */ IPAddress(const IPAddressV6& ipV6Addr) noexcept;
  /* implicit */ IPAddress(const in6_addr& addr) noexcept;

  // Assign from V4 address
  IPAddress& operator=(const IPAddressV4& ipV4Addr) noexcept;

  // Assign from V6 address
  IPAddress& operator=(const IPAddressV6& ipV6Addr) noexcept;

  const IPAddressV4& asV4() const {
    if (UNLIKELY(!isV4())) {
      asV4Throw();
    }
    return addr_.ipV4Addr;
  }

  const IPAddressV6& asV6() const {
    if (UNLIKELY(!isV6())) {
      asV6Throw();
    }
    return addr_.ipV6Addr;
  }

  // Return sa_family_t of IPAddress
  sa_family_t family() const {
    return family_;
  }

  // Populate sockaddr_storage with an appropriate value
  int toSockaddrStorage(sockaddr_storage* dest, uint16_t port = 0) const {
    if (dest == nullptr) {
      throw IPAddressFormatException("dest must not be null");
    }
    memset(dest, 0, sizeof(sockaddr_storage));
    dest->ss_family = family();

    if (isV4()) {
      sockaddr_in* sin = reinterpret_cast<sockaddr_in*>(dest);
      sin->sin_addr = asV4().toAddr();
      sin->sin_port = port;
#if defined(__APPLE__)
      sin->sin_len = sizeof(*sin);
#endif
      return sizeof(*sin);
    } else if (isV6()) {
      sockaddr_in6* sin = reinterpret_cast<sockaddr_in6*>(dest);
      sin->sin6_addr = asV6().toAddr();
      sin->sin6_port = port;
      sin->sin6_scope_id = asV6().getScopeId();
#if defined(__APPLE__)
      sin->sin6_len = sizeof(*sin);
#endif
      return sizeof(*sin);
    } else {
      throw InvalidAddressFamilyException(family());
    }
  }

  bool inSubnet(StringPiece ipSlashCidr) const;

  bool inSubnet(const IPAddress& subnet, uint8_t cidr) const;

  bool inSubnetWithMask(const IPAddress& subnet, ByteRange mask) const;

  // @return true if address is a v4 mapped address
  bool isIPv4Mapped() const {
    return isV6() && asV6().isIPv4Mapped();
  }

  // @return true if address is uninitialized
  bool empty() const {
    return family_ == AF_UNSPEC;
  }

  // @return true if address is initialized
  explicit operator bool() const {
    return !empty();
  }

  // @return true if this is an IPAddressV4 instance
  bool isV4() const {
    return family_ == AF_INET;
  }

  // @return true if this is an IPAddressV6 instance
  bool isV6() const {
    return family_ == AF_INET6;
  }

  // @return true if this address is all zeros
  bool isZero() const {
    return pick([&](auto& _) { return _.isZero(); });
  }

  // Number of bits in the address representation.
  size_t bitCount() const {
    return pick([&](auto& _) { return _.bitCount(); });
  }
  // Number of bytes in the address representation.
  size_t byteCount() const {
    return bitCount() / 8;
  }
  // get nth most significant bit - 0 indexed
  bool getNthMSBit(size_t bitIndex) const {
    return detail::getNthMSBitImpl(*this, bitIndex, family());
  }
  // get nth most significant byte - 0 indexed
  uint8_t getNthMSByte(size_t byteIndex) const;
  // get nth bit - 0 indexed
  bool getNthLSBit(size_t bitIndex) const {
    return getNthMSBit(bitCount() - bitIndex - 1);
  }
  // get nth byte - 0 indexed
  uint8_t getNthLSByte(size_t byteIndex) const {
    return getNthMSByte(byteCount() - byteIndex - 1);
  }
  std::string toJson() const {
    return pick([&](auto& _) { return _.toJson(); });
  }

  // Hash of address
  std::size_t hash() const {
    return pick([&](auto& _) { return _.hash(); });
  }

  // Return true if the address qualifies as localhost.
  bool isLoopback() const {
    return pick([&](auto& _) { return _.isLoopback(); });
  }

  // Return true if the address qualifies as link local
  bool isLinkLocal() const {
    return pick([&](auto& _) { return _.isLinkLocal(); });
  }

  // Return true if the address qualifies as broadcast.
  bool isLinkLocalBroadcast() const {
    return pick([&](auto& _) { return _.isLinkLocalBroadcast(); });
  }

  bool isNonroutable() const {
    return pick([&](auto& _) { return _.isNonroutable(); });
  }

  bool isPrivate() const {
    return pick([&](auto& _) { return _.isPrivate(); });
  }

  // Return true if the address is a multicast address.
  bool isMulticast() const {
    return pick([&](auto& _) { return _.isMulticast(); });
  }

  IPAddress mask(uint8_t numBits) const {
    return pick([&](auto& _) { return IPAddress(_.mask(numBits)); });
  }

  std::string str() const {
    return pick([&](auto& _) { return _.str(); });
  }

  std::string toFullyQualified() const {
    return pick([&](auto& _) { return _.toFullyQualified(); });
  }

  void toFullyQualifiedAppend(std::string& out) const {
    return pick([&](auto& _) { return _.toFullyQualifiedAppend(out); });
  }

  // Address version (4 or 6)
  uint8_t version() const {
    return pick([&](auto& _) { return _.version(); });
  }

  const unsigned char* bytes() const {
    return pick([&](auto& _) { return _.bytes(); });
  }

 private:
  [[noreturn]] void asV4Throw() const;
  [[noreturn]] void asV6Throw() const;

  typedef union IPAddressV46 {
    IPAddressV4 ipV4Addr;
    IPAddressV6 ipV6Addr;
    // default constructor
    IPAddressV46() noexcept {
      std::memset(this, 0, sizeof(IPAddressV46));
    }
    explicit IPAddressV46(const IPAddressV4& addr) noexcept : ipV4Addr(addr) {}
    explicit IPAddressV46(const IPAddressV6& addr) noexcept : ipV6Addr(addr) {}
  } IPAddressV46;
  IPAddressV46 addr_;
  sa_family_t family_;
};

// boost::hash uses hash_value() so this allows boost::hash to work
// automatically for IPAddress
std::size_t hash_value(const IPAddress& addr);
std::ostream& operator<<(std::ostream& os, const IPAddress& addr);
// Define toAppend() to allow IPAddress to be used with folly::to<string>
void toAppend(IPAddress addr, std::string* result);
void toAppend(IPAddress addr, fbstring* result);

bool operator==(const IPAddress& addr1, const IPAddress& addr2);
// Return true if addr1 < addr2
bool operator<(const IPAddress& addr1, const IPAddress& addr2);
// Derived operators
inline bool operator!=(const IPAddress& a, const IPAddress& b) {
  return !(a == b);
}
inline bool operator>(const IPAddress& a, const IPAddress& b) {
  return b < a;
}
inline bool operator<=(const IPAddress& a, const IPAddress& b) {
  return !(a > b);
}
inline bool operator>=(const IPAddress& a, const IPAddress& b) {
  return !(a < b);
}

} // namespace folly

namespace std {
template <>
struct hash<folly::IPAddress> {
  size_t operator()(const folly::IPAddress& addr) const {
    return addr.hash();
  }
};
} // namespace std