doip_message.cpp

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/* Diagnostic Client library
* Copyright (C) 2024  Avijit Dey
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#include "common/doip_message.h"
 
namespace doip_client {
namespace {
 
auto GetDoIPPayloadType(core_type::Span<std::uint8_t const> payload) noexcept -> std::uint16_t {
  return (static_cast<std::uint16_t>(((payload[2u] & 0xFF) << 8) | (payload[3u] & 0xFF)));
}
 
auto GetDoIPPayloadLength(core_type::Span<std::uint8_t const> payload) noexcept -> std::uint32_t {
  return ((static_cast<std::uint32_t>(payload[4u] << 24) & 0xFF000000) |
          (static_cast<std::uint32_t>(payload[5u] << 16) & 0x00FF0000) |
          (static_cast<std::uint32_t>(payload[6u] << 8) & 0x0000FF00) |
          (static_cast<std::uint32_t>(payload[7u] & 0x000000FF)));
}
 
auto ConvertToAddr(core_type::Span<std::uint8_t const> payload) noexcept -> std::uint16_t {
  return static_cast<std::uint16_t>(((payload[0u] << 8) & 0xFF00) | payload[1u]);
}
 
}  // namespace
 
DoipMessage::DoipMessage(MessageType message_type, DoipMessage::IpAddressType host_ip_address,
                         std::uint16_t host_port_number,
                         core_type::Span<std::uint8_t const> payload)
    : host_ip_address_{host_ip_address},
      host_port_number_{host_port_number},
      protocol_version_{payload[0u]},
      protocol_version_inv_{payload[1u]},
      server_address_{0u},
      client_address_{0u},
      payload_type_{GetDoIPPayloadType(payload)},
      payload_length_{GetDoIPPayloadLength(payload)} {
  constexpr std::uint8_t kDoipHeaderSize{8u};
  constexpr std::uint8_t kSourceAddressSize{4u};
  if (message_type == MessageType::kTcp) {
    payload_ = core_type::Span<std::uint8_t const>{
        &payload[kDoipHeaderSize + kSourceAddressSize],
        payload.size() - (kDoipHeaderSize + kSourceAddressSize)};
  } else {
    payload_ = core_type::Span<std::uint8_t const>{&payload[kDoipHeaderSize],
                                                   payload.size() - kDoipHeaderSize};
  }
 
  if (message_type == MessageType::kTcp) {
    client_address_ =
        ConvertToAddr(core_type::Span<std::uint8_t const>{&payload[kDoipHeaderSize], 2u});
    server_address_ =
        ConvertToAddr(core_type::Span<std::uint8_t const>{&payload[kDoipHeaderSize + 2u], 2u});
  }  // no client
}
 
}  // namespace doip_client