redfish-core/include/utils/ip_utils.hpp

#pragma once

#include <string>
#include <cstdint>

#include "boost/asio/ip/address_v4.hpp" // NOLINT
#include "boost/asio/ip/address_v6.hpp" // NOLINT
#include "boost/asio/ip/address.hpp" // NOLINT

namespace redfish {
namespace ip_util {

/**
 * @brief Converts boost::asio::ip::address to string
 * Will automatically convert IPv4-mapped IPv6 address back to IPv4.
 *
 * @param[in] ipAddr IP address to convert
 *
 * @return IP address string
 */
inline std::string toString(const boost::asio::ip::address& ipAddr) {
  if (ipAddr.is_v6() && ipAddr.to_v6().is_v4_mapped()) {
    return boost::asio::ip::make_address_v4(boost::asio::ip::v4_mapped,
                                            ipAddr.to_v6())
        .to_string();
  }
  return ipAddr.to_string();
}

/**
 * @brief Helper function that verifies IP address to check if it is in
 *        proper format. If bits pointer is provided, also calculates active
 *        bit count for Subnet Mask.
 *
 * @param[in]  ip     IP that will be verified
 * @param[out] bits   Calculated mask in bits notation
 *
 * @return true in case of success, false otherwise
 */
inline bool ipv4VerifyIpAndGetBitcount(const std::string& ip,
                                       uint8_t* prefixLength = nullptr) {
  boost::system::error_code ec;
  boost::asio::ip::address_v4 addr = boost::asio::ip::make_address_v4(ip, ec);
  if (ec) {
    return false;
  }

  if (prefixLength != nullptr) {
    uint8_t prefix = 0;
    boost::asio::ip::address_v4::bytes_type maskBytes = addr.to_bytes();
    bool maskFinished = false;
    for (unsigned char byte : maskBytes) {
      if (maskFinished) {
        if (byte != 0U) {
          return false;
        }
        continue;
      }
      switch (byte) {
        case 255:
          prefix += 8;
          break;
        case 254:
          prefix += 7;
          maskFinished = true;
          break;
        case 252:
          prefix += 6;
          maskFinished = true;
          break;
        case 248:
          prefix += 5;
          maskFinished = true;
          break;
        case 240:
          prefix += 4;
          maskFinished = true;
          break;
        case 224:
          prefix += 3;
          maskFinished = true;
          break;
        case 192:
          prefix += 2;
          maskFinished = true;
          break;
        case 128:
          prefix += 1;
          maskFinished = true;
          break;
        case 0:
          maskFinished = true;
          break;
        default:
          // Invalid netmask
          return false;
      }
    }
    *prefixLength = prefix;
  }

  return true;
}

}  // namespace ip_util
}  // namespace redfish