icmp4.hpp

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//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012- OpenVPN Inc.
//
//    SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
 
// Define the ICMPv4 header
 
#pragma once
 
#include <cstdint> // for std::uint32_t, uint16_t, uint8_t
 
#include <openvpn/ip/ip4.hpp>
 
#pragma pack(push)
#pragma pack(1)
 
namespace openvpn {
struct ICMPv4
{
    enum
    {
        ECHO_REQUEST = 8,
        ECHO_REPLY = 0,
        DEST_UNREACH = 3,
        FRAG_NEEDED = 4,
        MIN_DATA_SIZE = 8
    };
 
    struct IPv4Header head;
 
    union {
        struct
        {
            std::uint8_t type;
            std::uint8_t code;
        };
        std::uint16_t type_code;
    };
    std::uint16_t checksum;
 
    union {
        struct
        {
            std::uint16_t id;
            std::uint16_t seq_num;
        };
        struct
        {
            std::uint16_t unused;
            std::uint16_t nexthop_mtu;
        };
    };
};
} // namespace openvpn
 
#pragma pack(pop)