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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
//
#ifndef OPENVPN_COMPRESS_LZO_H
#define OPENVPN_COMPRESS_LZO_H
// Implement LZO compression.
// Should only be included by lzoselect.hpp
#include "lzo/lzoutil.h"
#include "lzo/lzo1x.h"
namespace openvpn {
class CompressLZO : public Compress
{
public:
// magic number for LZO compression
enum
{
LZO_COMPRESS = 0x66,
LZO_COMPRESS_SWAP = 0x67,
};
OPENVPN_SIMPLE_EXCEPTION(lzo_init_failed);
CompressLZO(const Frame::Ptr &frame,
const SessionStats::Ptr &stats,
const bool support_swap_arg,
const bool asym_arg)
: Compress(frame, stats),
support_swap(support_swap_arg),
asym(asym_arg)
{
OVPN_LOG_INFO("LZO init swap=" << support_swap_arg << " asym=" << asym_arg);
lzo_workspace.init(LZO1X_1_15_MEM_COMPRESS, BufAllocFlags::ARRAY);
}
static void init_static()
{
if (::lzo_init() != LZO_E_OK)
throw lzo_init_failed();
}
const char *name() const override
{
return "lzo";
}
void decompress_work(BufferAllocated &buf)
{
// initialize work buffer
lzo_uint zlen = frame->prepare(Frame::DECOMPRESS_WORK, work);
// do uncompress
const int err = lzo1x_decompress_safe(buf.c_data(), buf.size(), work.data(), &zlen, lzo_workspace.data());
if (err != LZO_E_OK)
{
error(buf);
return;
}
OVPN_LOG_VERBOSE("LZO uncompress " << buf.size() << " -> " << zlen);
work.set_size(zlen);
buf.swap(work);
}
void compress(BufferAllocated &buf, const bool hint) override
{
// skip null packets
if (!buf.size())
return;
if (hint && !asym)
{
// initialize work buffer
frame->prepare(Frame::COMPRESS_WORK, work);
// verify that input data length is not too large
if (lzo_extra_buffer(buf.size()) > work.max_size())
{
error(buf);
return;
}
// do compress
lzo_uint zlen = 0;
const int err = ::lzo1x_1_15_compress(buf.c_data(), buf.size(), work.data(), &zlen, lzo_workspace.data());
// check for errors
if (err != LZO_E_OK)
{
error(buf);
return;
}
// did compression actually reduce data length?
if (zlen < buf.size())
{
OVPN_LOG_VERBOSE("LZO compress " << buf.size() << " -> " << zlen);
work.set_size(zlen);
if (support_swap)
do_swap(work, LZO_COMPRESS_SWAP);
else
work.push_front(LZO_COMPRESS);
buf.swap(work);
return;
}
}
// indicate that we didn't compress
if (support_swap)
do_swap(buf, NO_COMPRESS_SWAP);
else
buf.push_front(NO_COMPRESS);
}
void decompress(BufferAllocated &buf) override
{
// skip null packets
if (!buf.size())
return;
const unsigned char c = buf.pop_front();
switch (c)
{
case NO_COMPRESS_SWAP:
do_unswap(buf);
[[fallthrough]];
case NO_COMPRESS:
break;
case LZO_COMPRESS_SWAP:
do_unswap(buf);
[[fallthrough]];
case LZO_COMPRESS:
decompress_work(buf);
break;
default:
error(buf); // unknown op
}
}
private:
// worst case size expansion on compress
size_t lzo_extra_buffer(const size_t len)
{
return len + len / 8 + 128 + 3;
}
const bool support_swap;
const bool asym;
BufferAllocated work;
BufferAllocated lzo_workspace;
};
} // namespace openvpn
#endif // OPENVPN_COMPRESS_LZO_H
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