mirror of
https://github.com/OpenVPN/openvpn3.git
synced 2024-09-20 12:12:15 +02:00
dde1574596
This is the result after running 'clang-format -i' on all C++ files and headers, with the defined formatting rules in .clang-format. Only the openvpn/common/unicode-impl.hpp has been excluded, as that is mostly a copy of an external project. Signed-off-by: David Sommerseth <davids@openvpn.net>
175 lines
4.5 KiB
C++
175 lines
4.5 KiB
C++
// 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 <http://www.gnu.org/licenses/>.
|
|
|
|
// IP checksum based on Linux kernel implementation
|
|
|
|
#pragma once
|
|
|
|
#include <cstdint>
|
|
|
|
#include <openvpn/common/endian.hpp>
|
|
#include <openvpn/common/socktypes.hpp>
|
|
#include <openvpn/common/size.hpp>
|
|
|
|
namespace openvpn {
|
|
namespace IPChecksum {
|
|
|
|
inline std::uint16_t fold(std::uint32_t sum)
|
|
{
|
|
sum = (sum >> 16) + (sum & 0xffff);
|
|
sum += (sum >> 16);
|
|
return sum;
|
|
}
|
|
|
|
inline std::uint16_t cfold(const std::uint32_t sum)
|
|
{
|
|
return ~fold(sum);
|
|
}
|
|
|
|
inline std::uint32_t unfold(const std::uint16_t sum)
|
|
{
|
|
return sum;
|
|
}
|
|
|
|
inline std::uint32_t cunfold(const std::uint16_t sum)
|
|
{
|
|
return ~unfold(sum);
|
|
}
|
|
|
|
inline std::uint32_t compute(const std::uint8_t *buf, size_t len)
|
|
{
|
|
std::uint32_t result = 0;
|
|
|
|
if (!len)
|
|
return 0;
|
|
|
|
const bool odd = size_t(buf) & 1;
|
|
if (odd)
|
|
{
|
|
#ifdef OPENVPN_LITTLE_ENDIAN
|
|
result += (*buf << 8);
|
|
#else
|
|
result = *buf;
|
|
#endif
|
|
len--;
|
|
buf++;
|
|
}
|
|
|
|
if (len >= 2)
|
|
{
|
|
if (size_t(buf) & 2)
|
|
{
|
|
result += *(std::uint16_t *)buf;
|
|
len -= 2;
|
|
buf += 2;
|
|
}
|
|
if (len >= 4)
|
|
{
|
|
const uint8_t *end = buf + (len & ~3);
|
|
std::uint32_t carry = 0;
|
|
do
|
|
{
|
|
std::uint32_t w = *(std::uint32_t *)buf;
|
|
buf += 4;
|
|
result += carry;
|
|
result += w;
|
|
carry = (w > result);
|
|
} while (buf < end);
|
|
result += carry;
|
|
result = (result & 0xffff) + (result >> 16);
|
|
}
|
|
if (len & 2)
|
|
{
|
|
result += *(std::uint16_t *)buf;
|
|
buf += 2;
|
|
}
|
|
}
|
|
if (len & 1)
|
|
{
|
|
#ifdef OPENVPN_LITTLE_ENDIAN
|
|
result += *buf;
|
|
#else
|
|
result += (*buf << 8);
|
|
#endif
|
|
}
|
|
result = fold(result);
|
|
if (odd)
|
|
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
|
|
return result;
|
|
}
|
|
|
|
inline std::uint32_t compute(const void *buf, const size_t len)
|
|
{
|
|
return compute((const std::uint8_t *)buf, len);
|
|
}
|
|
|
|
inline std::uint32_t partial(const void *buf, const size_t len, const std::uint32_t sum)
|
|
{
|
|
std::uint32_t result = compute(buf, len);
|
|
|
|
/* add in old sum, and carry.. */
|
|
result += sum;
|
|
if (sum > result)
|
|
result += 1;
|
|
return result;
|
|
}
|
|
|
|
inline std::uint32_t diff16(const std::uint32_t *old,
|
|
const std::uint32_t *new_,
|
|
const std::uint32_t oldsum)
|
|
{
|
|
// clang-format off
|
|
std::uint32_t diff[8] = {~old[0], ~old[1], ~old[2], ~old[3],
|
|
new_[0], new_[1], new_[2], new_[3]};
|
|
return partial(diff, sizeof(diff), oldsum);
|
|
// clang-format on
|
|
}
|
|
|
|
inline std::uint32_t diff16(const std::uint8_t *old,
|
|
const std::uint8_t *new_,
|
|
const std::uint32_t oldsum)
|
|
{
|
|
return diff16((const std::uint32_t *)old, (const std::uint32_t *)new_, oldsum);
|
|
}
|
|
|
|
inline std::uint32_t diff4(const std::uint32_t old,
|
|
const std::uint32_t new_,
|
|
const std::uint32_t oldsum)
|
|
{
|
|
std::uint32_t diff[2] = {~old, new_};
|
|
return partial(diff, sizeof(diff), oldsum);
|
|
}
|
|
|
|
inline std::uint32_t diff2(const std::uint16_t old,
|
|
const std::uint16_t new_,
|
|
const std::uint32_t oldsum)
|
|
{
|
|
std::uint16_t diff[2] = {std::uint16_t(~old), new_};
|
|
return partial(diff, sizeof(diff), oldsum);
|
|
}
|
|
|
|
inline std::uint16_t checksum(const void *data, const size_t size)
|
|
{
|
|
return cfold(compute(data, size));
|
|
}
|
|
} // namespace IPChecksum
|
|
} // namespace openvpn
|