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3c0ef626 | 1 | /* |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Interface to packet compression for ssh. | |
6 | * | |
7 | * As far as I am concerned, the code I have written for this software | |
8 | * can be used freely for any purpose. Any derived versions of this | |
9 | * software must be clearly marked as such, and if the derived work is | |
10 | * incompatible with the protocol description in the RFC file, it must be | |
11 | * called by a name other than "ssh" or "Secure Shell". | |
12 | */ | |
13 | ||
14 | #include "includes.h" | |
2980ea68 | 15 | RCSID("$OpenBSD: compress.c,v 1.19 2002/03/18 17:31:54 provos Exp $"); |
3c0ef626 | 16 | |
17 | #include "log.h" | |
18 | #include "buffer.h" | |
19 | #include "zlib.h" | |
20 | #include "compress.h" | |
21 | ||
2980ea68 | 22 | z_stream incoming_stream; |
23 | z_stream outgoing_stream; | |
3c0ef626 | 24 | static int compress_init_send_called = 0; |
25 | static int compress_init_recv_called = 0; | |
2980ea68 | 26 | static int inflate_failed = 0; |
27 | static int deflate_failed = 0; | |
3c0ef626 | 28 | |
29 | /* | |
30 | * Initializes compression; level is compression level from 1 to 9 | |
31 | * (as in gzip). | |
32 | */ | |
33 | ||
34 | void | |
35 | buffer_compress_init_send(int level) | |
36 | { | |
37 | if (compress_init_send_called == 1) | |
38 | deflateEnd(&outgoing_stream); | |
39 | compress_init_send_called = 1; | |
40 | debug("Enabling compression at level %d.", level); | |
41 | if (level < 1 || level > 9) | |
42 | fatal("Bad compression level %d.", level); | |
43 | deflateInit(&outgoing_stream, level); | |
44 | } | |
45 | void | |
46 | buffer_compress_init_recv(void) | |
47 | { | |
48 | if (compress_init_recv_called == 1) | |
49 | inflateEnd(&incoming_stream); | |
50 | compress_init_recv_called = 1; | |
51 | inflateInit(&incoming_stream); | |
52 | } | |
53 | ||
54 | /* Frees any data structures allocated for compression. */ | |
55 | ||
56 | void | |
57 | buffer_compress_uninit(void) | |
58 | { | |
59 | debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f", | |
e9a17296 | 60 | outgoing_stream.total_in, outgoing_stream.total_out, |
61 | outgoing_stream.total_in == 0 ? 0.0 : | |
62 | (double) outgoing_stream.total_out / outgoing_stream.total_in); | |
3c0ef626 | 63 | debug("compress incoming: raw data %lu, compressed %lu, factor %.2f", |
e9a17296 | 64 | incoming_stream.total_out, incoming_stream.total_in, |
65 | incoming_stream.total_out == 0 ? 0.0 : | |
66 | (double) incoming_stream.total_in / incoming_stream.total_out); | |
2980ea68 | 67 | if (compress_init_recv_called == 1 && inflate_failed == 0) |
3c0ef626 | 68 | inflateEnd(&incoming_stream); |
2980ea68 | 69 | if (compress_init_send_called == 1 && deflate_failed == 0) |
3c0ef626 | 70 | deflateEnd(&outgoing_stream); |
71 | } | |
72 | ||
73 | /* | |
74 | * Compresses the contents of input_buffer into output_buffer. All packets | |
75 | * compressed using this function will form a single compressed data stream; | |
76 | * however, data will be flushed at the end of every call so that each | |
77 | * output_buffer can be decompressed independently (but in the appropriate | |
78 | * order since they together form a single compression stream) by the | |
79 | * receiver. This appends the compressed data to the output buffer. | |
80 | */ | |
81 | ||
82 | void | |
83 | buffer_compress(Buffer * input_buffer, Buffer * output_buffer) | |
84 | { | |
e9a17296 | 85 | u_char buf[4096]; |
3c0ef626 | 86 | int status; |
87 | ||
88 | /* This case is not handled below. */ | |
89 | if (buffer_len(input_buffer) == 0) | |
90 | return; | |
91 | ||
92 | /* Input is the contents of the input buffer. */ | |
e9a17296 | 93 | outgoing_stream.next_in = buffer_ptr(input_buffer); |
3c0ef626 | 94 | outgoing_stream.avail_in = buffer_len(input_buffer); |
95 | ||
96 | /* Loop compressing until deflate() returns with avail_out != 0. */ | |
97 | do { | |
98 | /* Set up fixed-size output buffer. */ | |
e9a17296 | 99 | outgoing_stream.next_out = buf; |
3c0ef626 | 100 | outgoing_stream.avail_out = sizeof(buf); |
101 | ||
102 | /* Compress as much data into the buffer as possible. */ | |
103 | status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH); | |
104 | switch (status) { | |
105 | case Z_OK: | |
106 | /* Append compressed data to output_buffer. */ | |
107 | buffer_append(output_buffer, buf, | |
108 | sizeof(buf) - outgoing_stream.avail_out); | |
109 | break; | |
110 | default: | |
2980ea68 | 111 | deflate_failed = 1; |
3c0ef626 | 112 | fatal("buffer_compress: deflate returned %d", status); |
113 | /* NOTREACHED */ | |
114 | } | |
115 | } while (outgoing_stream.avail_out == 0); | |
116 | } | |
117 | ||
118 | /* | |
119 | * Uncompresses the contents of input_buffer into output_buffer. All packets | |
120 | * uncompressed using this function will form a single compressed data | |
121 | * stream; however, data will be flushed at the end of every call so that | |
122 | * each output_buffer. This must be called for the same size units that the | |
123 | * buffer_compress was called, and in the same order that buffers compressed | |
124 | * with that. This appends the uncompressed data to the output buffer. | |
125 | */ | |
126 | ||
127 | void | |
128 | buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer) | |
129 | { | |
e9a17296 | 130 | u_char buf[4096]; |
3c0ef626 | 131 | int status; |
132 | ||
e9a17296 | 133 | incoming_stream.next_in = buffer_ptr(input_buffer); |
3c0ef626 | 134 | incoming_stream.avail_in = buffer_len(input_buffer); |
135 | ||
136 | for (;;) { | |
137 | /* Set up fixed-size output buffer. */ | |
e9a17296 | 138 | incoming_stream.next_out = buf; |
3c0ef626 | 139 | incoming_stream.avail_out = sizeof(buf); |
140 | ||
141 | status = inflate(&incoming_stream, Z_PARTIAL_FLUSH); | |
142 | switch (status) { | |
143 | case Z_OK: | |
144 | buffer_append(output_buffer, buf, | |
145 | sizeof(buf) - incoming_stream.avail_out); | |
146 | break; | |
147 | case Z_BUF_ERROR: | |
148 | /* | |
149 | * Comments in zlib.h say that we should keep calling | |
150 | * inflate() until we get an error. This appears to | |
151 | * be the error that we get. | |
152 | */ | |
153 | return; | |
154 | default: | |
2980ea68 | 155 | inflate_failed = 1; |
3c0ef626 | 156 | fatal("buffer_uncompress: inflate returned %d", status); |
157 | /* NOTREACHED */ | |
158 | } | |
159 | } | |
160 | } |