mirror of
https://github.com/OpenVPN/openvpn3.git
synced 2024-09-20 12:12:15 +02:00
97 lines
3.6 KiB
C++
97 lines
3.6 KiB
C++
// OpenVPN -- An application to securely tunnel IP networks
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// over a single port, with support for SSL/TLS-based
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// session authentication and key exchange,
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// packet encryption, packet authentication, and
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// packet compression.
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//
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// Copyright (C) 2012-2020 OpenVPN Inc.
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License Version 3
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// as published by the Free Software Foundation.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program in the COPYING file.
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// If not, see <http://www.gnu.org/licenses/>.
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#pragma once
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#include <cstdint> // for std::uint32_t, uint64_t, etc.
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#include <lz4.h>
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#include <openvpn/common/exception.hpp>
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#include <openvpn/common/socktypes.hpp> // for ntohl/htonl
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#include <openvpn/buffer/buffer.hpp>
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namespace openvpn {
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namespace LZ4 {
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OPENVPN_EXCEPTION(lz4_error);
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inline BufferPtr compress(const ConstBuffer& src,
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const size_t headroom,
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const size_t tailroom)
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{
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// sanity check
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if (src.size() > LZ4_MAX_INPUT_SIZE)
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OPENVPN_THROW(lz4_error, "compress buffer size=" << src.size() << " exceeds LZ4_MAX_INPUT_SIZE=" << LZ4_MAX_INPUT_SIZE);
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// allocate dest buffer
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BufferPtr dest = new BufferAllocated(sizeof(std::uint32_t) + headroom + tailroom + LZ4_COMPRESSBOUND(src.size()), 0);
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dest->init_headroom(headroom);
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// as a hint to receiver, write the decompressed size
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{
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const std::uint32_t size = htonl(src.size());
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dest->write(&size, sizeof(size));
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}
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// compress
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const int comp_size = ::LZ4_compress_default((const char *)src.c_data(), (char *)dest->data_end(),
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(int)src.size(), (int)dest->remaining(tailroom));
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if (comp_size <= 0)
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OPENVPN_THROW(lz4_error, "LZ4_compress_default returned error status=" << comp_size);
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dest->inc_size(comp_size);
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return dest;
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}
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inline BufferPtr decompress(const ConstBuffer& source,
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const size_t headroom,
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const size_t tailroom,
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size_t max_decompressed_size=LZ4_MAX_INPUT_SIZE)
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{
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// get the decompressed size
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ConstBuffer src(source);
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if (src.size() < sizeof(std::uint32_t))
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OPENVPN_THROW(lz4_error, "decompress buffer size=" << src.size() << " is too small");
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std::uint32_t size;
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src.read(&size, sizeof(size));
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size = ntohl(size);
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if (max_decompressed_size > LZ4_MAX_INPUT_SIZE)
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max_decompressed_size = LZ4_MAX_INPUT_SIZE;
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if (max_decompressed_size && size > max_decompressed_size)
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OPENVPN_THROW(lz4_error, "decompress expansion size=" << size << " is too large (must be <= " << max_decompressed_size << ')');
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// allocate dest buffer
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BufferPtr dest = new BufferAllocated(headroom + tailroom + size, 0);
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dest->init_headroom(headroom);
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// decompress
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const int decomp_size = LZ4_decompress_safe((const char *)src.c_data(), (char *)dest->data(),
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(int)src.size(), size);
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if (decomp_size <= 0)
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OPENVPN_THROW(lz4_error, "LZ4_decompress_safe returned error status=" << decomp_size);
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if (static_cast<unsigned int>(decomp_size) != size)
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OPENVPN_THROW(lz4_error, "decompress size inconsistency expected_size=" << size << " actual_size=" << decomp_size);
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dest->inc_size(decomp_size);
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return dest;
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}
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}
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}
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