166 lines
4.8 KiB
C
166 lines
4.8 KiB
C
/*
|
|
*
|
|
* compress.c
|
|
*
|
|
* Author: Tatu Ylonen <ylo@cs.hut.fi>
|
|
*
|
|
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
|
|
* All rights reserved
|
|
*
|
|
* Created: Wed Oct 25 22:12:46 1995 ylo
|
|
*
|
|
* Interface to packet compression for ssh.
|
|
*
|
|
*/
|
|
|
|
#include "includes.h"
|
|
RCSID("$Id: compress.c,v 1.4 1999/11/24 19:53:46 markus Exp $");
|
|
|
|
#include "ssh.h"
|
|
#include "buffer.h"
|
|
#include "zlib.h"
|
|
|
|
static z_stream incoming_stream;
|
|
static z_stream outgoing_stream;
|
|
|
|
/*
|
|
* Initializes compression; level is compression level from 1 to 9
|
|
* (as in gzip).
|
|
*/
|
|
|
|
void
|
|
buffer_compress_init(int level)
|
|
{
|
|
debug("Enabling compression at level %d.", level);
|
|
if (level < 1 || level > 9)
|
|
fatal("Bad compression level %d.", level);
|
|
inflateInit(&incoming_stream);
|
|
deflateInit(&outgoing_stream, level);
|
|
}
|
|
|
|
/* Frees any data structures allocated for compression. */
|
|
|
|
void
|
|
buffer_compress_uninit()
|
|
{
|
|
debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
|
|
outgoing_stream.total_in, outgoing_stream.total_out,
|
|
outgoing_stream.total_in == 0 ? 0.0 :
|
|
(double) outgoing_stream.total_out / outgoing_stream.total_in);
|
|
debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
|
|
incoming_stream.total_out, incoming_stream.total_in,
|
|
incoming_stream.total_out == 0 ? 0.0 :
|
|
(double) incoming_stream.total_in / incoming_stream.total_out);
|
|
inflateEnd(&incoming_stream);
|
|
deflateEnd(&outgoing_stream);
|
|
}
|
|
|
|
/*
|
|
* Compresses the contents of input_buffer into output_buffer. All packets
|
|
* compressed using this function will form a single compressed data stream;
|
|
* however, data will be flushed at the end of every call so that each
|
|
* output_buffer can be decompressed independently (but in the appropriate
|
|
* order since they together form a single compression stream) by the
|
|
* receiver. This appends the compressed data to the output buffer.
|
|
*/
|
|
|
|
void
|
|
buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
|
|
{
|
|
char buf[4096];
|
|
int status;
|
|
|
|
/* This case is not handled below. */
|
|
if (buffer_len(input_buffer) == 0)
|
|
return;
|
|
|
|
/* Input is the contents of the input buffer. */
|
|
outgoing_stream.next_in = buffer_ptr(input_buffer);
|
|
outgoing_stream.avail_in = buffer_len(input_buffer);
|
|
|
|
/* Loop compressing until deflate() returns with avail_out != 0. */
|
|
do {
|
|
/* Set up fixed-size output buffer. */
|
|
outgoing_stream.next_out = buf;
|
|
outgoing_stream.avail_out = sizeof(buf);
|
|
|
|
/* Compress as much data into the buffer as possible. */
|
|
status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
|
|
switch (status) {
|
|
case Z_OK:
|
|
/* Append compressed data to output_buffer. */
|
|
buffer_append(output_buffer, buf,
|
|
sizeof(buf) - outgoing_stream.avail_out);
|
|
break;
|
|
case Z_STREAM_END:
|
|
fatal("buffer_compress: deflate returned Z_STREAM_END");
|
|
/* NOTREACHED */
|
|
case Z_STREAM_ERROR:
|
|
fatal("buffer_compress: deflate returned Z_STREAM_ERROR");
|
|
/* NOTREACHED */
|
|
case Z_BUF_ERROR:
|
|
fatal("buffer_compress: deflate returned Z_BUF_ERROR");
|
|
/* NOTREACHED */
|
|
default:
|
|
fatal("buffer_compress: deflate returned %d", status);
|
|
/* NOTREACHED */
|
|
}
|
|
}
|
|
while (outgoing_stream.avail_out == 0);
|
|
}
|
|
|
|
/*
|
|
* Uncompresses the contents of input_buffer into output_buffer. All packets
|
|
* uncompressed using this function will form a single compressed data
|
|
* stream; however, data will be flushed at the end of every call so that
|
|
* each output_buffer. This must be called for the same size units that the
|
|
* buffer_compress was called, and in the same order that buffers compressed
|
|
* with that. This appends the uncompressed data to the output buffer.
|
|
*/
|
|
|
|
void
|
|
buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
|
|
{
|
|
char buf[4096];
|
|
int status;
|
|
|
|
incoming_stream.next_in = buffer_ptr(input_buffer);
|
|
incoming_stream.avail_in = buffer_len(input_buffer);
|
|
|
|
incoming_stream.next_out = buf;
|
|
incoming_stream.avail_out = sizeof(buf);
|
|
|
|
for (;;) {
|
|
status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
|
|
switch (status) {
|
|
case Z_OK:
|
|
buffer_append(output_buffer, buf,
|
|
sizeof(buf) - incoming_stream.avail_out);
|
|
incoming_stream.next_out = buf;
|
|
incoming_stream.avail_out = sizeof(buf);
|
|
break;
|
|
case Z_STREAM_END:
|
|
fatal("buffer_uncompress: inflate returned Z_STREAM_END");
|
|
/* NOTREACHED */
|
|
case Z_DATA_ERROR:
|
|
fatal("buffer_uncompress: inflate returned Z_DATA_ERROR");
|
|
/* NOTREACHED */
|
|
case Z_STREAM_ERROR:
|
|
fatal("buffer_uncompress: inflate returned Z_STREAM_ERROR");
|
|
/* NOTREACHED */
|
|
case Z_BUF_ERROR:
|
|
/*
|
|
* Comments in zlib.h say that we should keep calling
|
|
* inflate() until we get an error. This appears to
|
|
* be the error that we get.
|
|
*/
|
|
return;
|
|
case Z_MEM_ERROR:
|
|
fatal("buffer_uncompress: inflate returned Z_MEM_ERROR");
|
|
/* NOTREACHED */
|
|
default:
|
|
fatal("buffer_uncompress: inflate returned %d", status);
|
|
}
|
|
}
|
|
}
|