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8efc0c15 | 1 | /* |
5260325f | 2 | * |
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 | */ | |
8efc0c15 | 15 | |
16 | #include "includes.h" | |
17 | RCSID("$Id$"); | |
18 | ||
19 | #include "ssh.h" | |
20 | #include "buffer.h" | |
21 | #include "zlib.h" | |
22 | ||
23 | static z_stream incoming_stream; | |
24 | static z_stream outgoing_stream; | |
25 | ||
aa3378df | 26 | /* |
27 | * Initializes compression; level is compression level from 1 to 9 | |
28 | * (as in gzip). | |
29 | */ | |
8efc0c15 | 30 | |
5260325f | 31 | void |
32 | buffer_compress_init(int level) | |
8efc0c15 | 33 | { |
5260325f | 34 | 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); | |
8efc0c15 | 39 | } |
40 | ||
41 | /* Frees any data structures allocated for compression. */ | |
42 | ||
5260325f | 43 | void |
44 | buffer_compress_uninit() | |
8efc0c15 | 45 | { |
5260325f | 46 | 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); | |
8efc0c15 | 56 | } |
57 | ||
aa3378df | 58 | /* |
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 | */ | |
8efc0c15 | 66 | |
5260325f | 67 | void |
68 | buffer_compress(Buffer * input_buffer, Buffer * output_buffer) | |
8efc0c15 | 69 | { |
5260325f | 70 | char buf[4096]; |
71 | int status; | |
72 | ||
73 | /* This case is not handled below. */ | |
74 | if (buffer_len(input_buffer) == 0) | |
75 | return; | |
76 | ||
77 | /* 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); | |
80 | ||
81 | /* 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); | |
86 | ||
87 | /* 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 | } | |
8efc0c15 | 108 | } |
5260325f | 109 | while (outgoing_stream.avail_out == 0); |
8efc0c15 | 110 | } |
111 | ||
aa3378df | 112 | /* |
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 | */ | |
8efc0c15 | 120 | |
5260325f | 121 | void |
122 | buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer) | |
8efc0c15 | 123 | { |
5260325f | 124 | char buf[4096]; |
125 | int status; | |
126 | ||
127 | incoming_stream.next_in = buffer_ptr(input_buffer); | |
128 | incoming_stream.avail_in = buffer_len(input_buffer); | |
129 | ||
130 | incoming_stream.next_out = buf; | |
131 | incoming_stream.avail_out = sizeof(buf); | |
132 | ||
133 | 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: | |
aa3378df | 152 | /* |
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 | */ | |
5260325f | 157 | 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 | } | |
8efc0c15 | 164 | } |
8efc0c15 | 165 | } |