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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 *
3 * compress.c
4 *
5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
6 *
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8 * All rights reserved
9 *
10 * Created: Wed Oct 25 22:12:46 1995 ylo
11 *
12 * Interface to packet compression for ssh.
13 *
14 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100015
16#include "includes.h"
Damien Miller5428f641999-11-25 11:54:57 +110017RCSID("$Id: compress.c,v 1.3 1999/11/25 00:54:59 damien Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100018
19#include "ssh.h"
20#include "buffer.h"
21#include "zlib.h"
22
23static z_stream incoming_stream;
24static z_stream outgoing_stream;
25
Damien Miller5428f641999-11-25 11:54:57 +110026/*
27 * Initializes compression; level is compression level from 1 to 9
28 * (as in gzip).
29 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100030
Damien Miller95def091999-11-25 00:26:21 +110031void
32buffer_compress_init(int level)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100033{
Damien Miller95def091999-11-25 00:26:21 +110034 debug("Enabling compression at level %d.", level);
35 if (level < 1 || level > 9)
36 fatal("Bad compression level %d.", level);
37 inflateInit(&incoming_stream);
38 deflateInit(&outgoing_stream, level);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039}
40
41/* Frees any data structures allocated for compression. */
42
Damien Miller95def091999-11-25 00:26:21 +110043void
44buffer_compress_uninit()
Damien Millerd4a8b7e1999-10-27 13:42:43 +100045{
Damien Miller95def091999-11-25 00:26:21 +110046 debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
47 outgoing_stream.total_in, outgoing_stream.total_out,
48 outgoing_stream.total_in == 0 ? 0.0 :
49 (double) outgoing_stream.total_out / outgoing_stream.total_in);
50 debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
51 incoming_stream.total_out, incoming_stream.total_in,
52 incoming_stream.total_out == 0 ? 0.0 :
53 (double) incoming_stream.total_in / incoming_stream.total_out);
54 inflateEnd(&incoming_stream);
55 deflateEnd(&outgoing_stream);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100056}
57
Damien Miller5428f641999-11-25 11:54:57 +110058/*
59 * Compresses the contents of input_buffer into output_buffer. All packets
60 * compressed using this function will form a single compressed data stream;
61 * however, data will be flushed at the end of every call so that each
62 * output_buffer can be decompressed independently (but in the appropriate
63 * order since they together form a single compression stream) by the
64 * receiver. This appends the compressed data to the output buffer.
65 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100066
Damien Miller95def091999-11-25 00:26:21 +110067void
68buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100069{
Damien Miller95def091999-11-25 00:26:21 +110070 char buf[4096];
71 int status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100072
Damien Miller95def091999-11-25 00:26:21 +110073 /* This case is not handled below. */
74 if (buffer_len(input_buffer) == 0)
75 return;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100076
Damien Miller95def091999-11-25 00:26:21 +110077 /* Input is the contents of the input buffer. */
78 outgoing_stream.next_in = buffer_ptr(input_buffer);
79 outgoing_stream.avail_in = buffer_len(input_buffer);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100080
Damien Miller95def091999-11-25 00:26:21 +110081 /* Loop compressing until deflate() returns with avail_out != 0. */
82 do {
83 /* Set up fixed-size output buffer. */
84 outgoing_stream.next_out = buf;
85 outgoing_stream.avail_out = sizeof(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100086
Damien Miller95def091999-11-25 00:26:21 +110087 /* Compress as much data into the buffer as possible. */
88 status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
89 switch (status) {
90 case Z_OK:
91 /* Append compressed data to output_buffer. */
92 buffer_append(output_buffer, buf,
93 sizeof(buf) - outgoing_stream.avail_out);
94 break;
95 case Z_STREAM_END:
96 fatal("buffer_compress: deflate returned Z_STREAM_END");
97 /* NOTREACHED */
98 case Z_STREAM_ERROR:
99 fatal("buffer_compress: deflate returned Z_STREAM_ERROR");
100 /* NOTREACHED */
101 case Z_BUF_ERROR:
102 fatal("buffer_compress: deflate returned Z_BUF_ERROR");
103 /* NOTREACHED */
104 default:
105 fatal("buffer_compress: deflate returned %d", status);
106 /* NOTREACHED */
107 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108 }
Damien Miller95def091999-11-25 00:26:21 +1100109 while (outgoing_stream.avail_out == 0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000110}
111
Damien Miller5428f641999-11-25 11:54:57 +1100112/*
113 * Uncompresses the contents of input_buffer into output_buffer. All packets
114 * uncompressed using this function will form a single compressed data
115 * stream; however, data will be flushed at the end of every call so that
116 * each output_buffer. This must be called for the same size units that the
117 * buffer_compress was called, and in the same order that buffers compressed
118 * with that. This appends the uncompressed data to the output buffer.
119 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000120
Damien Miller95def091999-11-25 00:26:21 +1100121void
122buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000123{
Damien Miller95def091999-11-25 00:26:21 +1100124 char buf[4096];
125 int status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000126
Damien Miller95def091999-11-25 00:26:21 +1100127 incoming_stream.next_in = buffer_ptr(input_buffer);
128 incoming_stream.avail_in = buffer_len(input_buffer);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000129
Damien Miller95def091999-11-25 00:26:21 +1100130 incoming_stream.next_out = buf;
131 incoming_stream.avail_out = sizeof(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000132
Damien Miller95def091999-11-25 00:26:21 +1100133 for (;;) {
134 status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
135 switch (status) {
136 case Z_OK:
137 buffer_append(output_buffer, buf,
138 sizeof(buf) - incoming_stream.avail_out);
139 incoming_stream.next_out = buf;
140 incoming_stream.avail_out = sizeof(buf);
141 break;
142 case Z_STREAM_END:
143 fatal("buffer_uncompress: inflate returned Z_STREAM_END");
144 /* NOTREACHED */
145 case Z_DATA_ERROR:
146 fatal("buffer_uncompress: inflate returned Z_DATA_ERROR");
147 /* NOTREACHED */
148 case Z_STREAM_ERROR:
149 fatal("buffer_uncompress: inflate returned Z_STREAM_ERROR");
150 /* NOTREACHED */
151 case Z_BUF_ERROR:
Damien Miller5428f641999-11-25 11:54:57 +1100152 /*
153 * Comments in zlib.h say that we should keep calling
154 * inflate() until we get an error. This appears to
155 * be the error that we get.
156 */
Damien Miller95def091999-11-25 00:26:21 +1100157 return;
158 case Z_MEM_ERROR:
159 fatal("buffer_uncompress: inflate returned Z_MEM_ERROR");
160 /* NOTREACHED */
161 default:
162 fatal("buffer_uncompress: inflate returned %d", status);
163 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000164 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000165}