// 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) 2012-2022 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see .
// IPv4 header
#pragma once
#include // for std::uint32_t, uint16_t, uint8_t
#pragma pack(push)
#pragma pack(1)
namespace openvpn {
struct IPv4Header
{
static unsigned int length(const std::uint8_t version_len)
{
return (version_len & 0x0F) << 2;
}
static std::uint8_t ver_len(const unsigned int version,
const unsigned int len)
{
return static_cast(((len >> 2) & 0x0F) | (version & 0x0F) << 4);
}
std::uint8_t version_len;
std::uint8_t tos;
std::uint16_t tot_len;
std::uint16_t id;
enum
{
OFFMASK = 0x1fff,
};
std::uint16_t frag_off;
std::uint8_t ttl;
std::uint8_t protocol;
std::uint16_t check;
std::uint32_t saddr;
std::uint32_t daddr;
/* The options start here. */
};
} // namespace openvpn
#pragma pack(pop)