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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" | |
416fd2a8 | 15 | RCSID("$OpenBSD: compress.c,v 1.21 2004/01/13 19:45:15 markus 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 | { | |
416fd2a8 | 59 | debug("compress outgoing: raw data %llu, compressed %llu, factor %.2f", |
60 | (unsigned long long)outgoing_stream.total_in, | |
61 | (unsigned long long)outgoing_stream.total_out, | |
e9a17296 | 62 | outgoing_stream.total_in == 0 ? 0.0 : |
63 | (double) outgoing_stream.total_out / outgoing_stream.total_in); | |
416fd2a8 | 64 | debug("compress incoming: raw data %llu, compressed %llu, factor %.2f", |
65 | (unsigned long long)incoming_stream.total_out, | |
66 | (unsigned long long)incoming_stream.total_in, | |
e9a17296 | 67 | incoming_stream.total_out == 0 ? 0.0 : |
68 | (double) incoming_stream.total_in / incoming_stream.total_out); | |
2980ea68 | 69 | if (compress_init_recv_called == 1 && inflate_failed == 0) |
3c0ef626 | 70 | inflateEnd(&incoming_stream); |
2980ea68 | 71 | if (compress_init_send_called == 1 && deflate_failed == 0) |
3c0ef626 | 72 | deflateEnd(&outgoing_stream); |
73 | } | |
74 | ||
75 | /* | |
76 | * Compresses the contents of input_buffer into output_buffer. All packets | |
77 | * compressed using this function will form a single compressed data stream; | |
78 | * however, data will be flushed at the end of every call so that each | |
79 | * output_buffer can be decompressed independently (but in the appropriate | |
80 | * order since they together form a single compression stream) by the | |
81 | * receiver. This appends the compressed data to the output buffer. | |
82 | */ | |
83 | ||
84 | void | |
85 | buffer_compress(Buffer * input_buffer, Buffer * output_buffer) | |
86 | { | |
e9a17296 | 87 | u_char buf[4096]; |
3c0ef626 | 88 | int status; |
89 | ||
90 | /* This case is not handled below. */ | |
91 | if (buffer_len(input_buffer) == 0) | |
92 | return; | |
93 | ||
94 | /* Input is the contents of the input buffer. */ | |
e9a17296 | 95 | outgoing_stream.next_in = buffer_ptr(input_buffer); |
3c0ef626 | 96 | outgoing_stream.avail_in = buffer_len(input_buffer); |
97 | ||
98 | /* Loop compressing until deflate() returns with avail_out != 0. */ | |
99 | do { | |
100 | /* Set up fixed-size output buffer. */ | |
e9a17296 | 101 | outgoing_stream.next_out = buf; |
3c0ef626 | 102 | outgoing_stream.avail_out = sizeof(buf); |
103 | ||
104 | /* Compress as much data into the buffer as possible. */ | |
105 | status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH); | |
106 | switch (status) { | |
107 | case Z_OK: | |
108 | /* Append compressed data to output_buffer. */ | |
109 | buffer_append(output_buffer, buf, | |
110 | sizeof(buf) - outgoing_stream.avail_out); | |
111 | break; | |
112 | default: | |
2980ea68 | 113 | deflate_failed = 1; |
3c0ef626 | 114 | fatal("buffer_compress: deflate returned %d", status); |
115 | /* NOTREACHED */ | |
116 | } | |
117 | } while (outgoing_stream.avail_out == 0); | |
118 | } | |
119 | ||
120 | /* | |
121 | * Uncompresses the contents of input_buffer into output_buffer. All packets | |
122 | * uncompressed using this function will form a single compressed data | |
123 | * stream; however, data will be flushed at the end of every call so that | |
124 | * each output_buffer. This must be called for the same size units that the | |
125 | * buffer_compress was called, and in the same order that buffers compressed | |
126 | * with that. This appends the uncompressed data to the output buffer. | |
127 | */ | |
128 | ||
129 | void | |
130 | buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer) | |
131 | { | |
e9a17296 | 132 | u_char buf[4096]; |
3c0ef626 | 133 | int status; |
134 | ||
e9a17296 | 135 | incoming_stream.next_in = buffer_ptr(input_buffer); |
3c0ef626 | 136 | incoming_stream.avail_in = buffer_len(input_buffer); |
137 | ||
138 | for (;;) { | |
139 | /* Set up fixed-size output buffer. */ | |
e9a17296 | 140 | incoming_stream.next_out = buf; |
3c0ef626 | 141 | incoming_stream.avail_out = sizeof(buf); |
142 | ||
143 | status = inflate(&incoming_stream, Z_PARTIAL_FLUSH); | |
144 | switch (status) { | |
145 | case Z_OK: | |
146 | buffer_append(output_buffer, buf, | |
147 | sizeof(buf) - incoming_stream.avail_out); | |
148 | break; | |
149 | case Z_BUF_ERROR: | |
150 | /* | |
151 | * Comments in zlib.h say that we should keep calling | |
152 | * inflate() until we get an error. This appears to | |
153 | * be the error that we get. | |
154 | */ | |
155 | return; | |
156 | default: | |
2980ea68 | 157 | inflate_failed = 1; |
3c0ef626 | 158 | fatal("buffer_uncompress: inflate returned %d", status); |
159 | /* NOTREACHED */ | |
160 | } | |
161 | } | |
162 | } |