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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2017 OpenVPN Technologies, Inc. <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif
#include "syshead.h"
#if defined(USE_COMP)
#include "comp.h"
#include "error.h"
#include "otime.h"
#include "memdbg.h"
static void
stub_compress_init(struct compress_context *compctx)
{
}
static void
stub_compress_uninit(struct compress_context *compctx)
{
}
static void
stub_compress(struct buffer *buf, struct buffer work,
struct compress_context *compctx,
const struct frame *frame)
{
if (buf->len <= 0)
{
return;
}
if (compctx->flags & COMP_F_SWAP)
{
uint8_t *head = BPTR(buf);
uint8_t *tail = BEND(buf);
ASSERT(buf_safe(buf, 1));
++buf->len;
/* move head byte of payload to tail */
*tail = *head;
*head = NO_COMPRESS_BYTE_SWAP;
}
else
{
uint8_t *header = buf_prepend(buf, 1);
*header = NO_COMPRESS_BYTE;
}
}
static void
stub_decompress(struct buffer *buf, struct buffer work,
struct compress_context *compctx,
const struct frame *frame)
{
uint8_t c;
if (buf->len <= 0)
{
return;
}
if (compctx->flags & COMP_F_SWAP)
{
uint8_t *head = BPTR(buf);
c = *head;
--buf->len;
*head = *BEND(buf);
if (c != NO_COMPRESS_BYTE_SWAP)
{
dmsg(D_COMP_ERRORS, "Bad compression stub (swap) decompression header byte: %d", c);
buf->len = 0;
}
}
else
{
c = *BPTR(buf);
ASSERT(buf_advance(buf, 1));
if (c != NO_COMPRESS_BYTE)
{
dmsg(D_COMP_ERRORS, "Bad compression stub decompression header byte: %d", c);
buf->len = 0;
}
}
}
static void
stubv2_compress(struct buffer *buf, struct buffer work,
struct compress_context *compctx,
const struct frame *frame)
{
if (buf->len <= 0)
{
return;
}
compv2_escape_data_ifneeded(buf);
}
static void
stubv2_decompress(struct buffer *buf, struct buffer work,
struct compress_context *compctx,
const struct frame *frame)
{
if (buf->len <= 0)
{
return;
}
uint8_t *head = BPTR(buf);
/* no compression or packet to short*/
if (head[0] != COMP_ALGV2_INDICATOR_BYTE)
{
return;
}
/* compression header (0x50) is present */
buf_advance(buf, 1);
/* Packet buffer too short (only 1 byte) */
if (buf->len <= 0)
{
return;
}
head = BPTR(buf);
buf_advance(buf, 1);
if (head[0] != COMP_ALGV2_UNCOMPRESSED_BYTE)
{
dmsg(D_COMP_ERRORS, "Bad compression stubv2 decompression header byte: %d", *head);
buf->len = 0;
return;
}
}
const struct compress_alg compv2_stub_alg = {
"stubv2",
stub_compress_init,
stub_compress_uninit,
stubv2_compress,
stubv2_decompress
};
const struct compress_alg comp_stub_alg = {
"stub",
stub_compress_init,
stub_compress_uninit,
stub_compress,
stub_decompress
};
#else /* if defined(USE_COMP) */
static void
dummy(void)
{
}
#endif /* USE_STUB */
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