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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
5260325f | 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
4 | * All rights reserved | |
5260325f | 5 | * Interface to packet compression for ssh. |
6ae2364d | 6 | * |
bcbf86ec | 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". | |
5260325f | 12 | */ |
8efc0c15 | 13 | |
14 | #include "includes.h" | |
6ba22c93 | 15 | RCSID("$OpenBSD: compress.c,v 1.14 2001/04/05 10:39:01 markus Exp $"); |
8efc0c15 | 16 | |
42f11eb2 | 17 | #include "log.h" |
8efc0c15 | 18 | #include "buffer.h" |
19 | #include "zlib.h" | |
5ca51e19 | 20 | #include "compress.h" |
8efc0c15 | 21 | |
22 | static z_stream incoming_stream; | |
23 | static z_stream outgoing_stream; | |
6ba22c93 | 24 | static int compress_init_send_called = 0; |
25 | static int compress_init_recv_called = 0; | |
8efc0c15 | 26 | |
aa3378df | 27 | /* |
28 | * Initializes compression; level is compression level from 1 to 9 | |
29 | * (as in gzip). | |
30 | */ | |
8efc0c15 | 31 | |
6ae2364d | 32 | void |
6ba22c93 | 33 | buffer_compress_init_send(int level) |
8efc0c15 | 34 | { |
6ba22c93 | 35 | if (compress_init_send_called == 1) |
36 | deflateEnd(&incoming_stream); | |
37 | compress_init_send_called = 1; | |
5260325f | 38 | debug("Enabling compression at level %d.", level); |
39 | if (level < 1 || level > 9) | |
40 | fatal("Bad compression level %d.", level); | |
5260325f | 41 | deflateInit(&outgoing_stream, level); |
8efc0c15 | 42 | } |
6ba22c93 | 43 | void |
44 | buffer_compress_init_recv(void) | |
45 | { | |
46 | if (compress_init_recv_called == 1) | |
47 | inflateEnd(&incoming_stream); | |
48 | compress_init_recv_called = 1; | |
49 | inflateInit(&incoming_stream); | |
50 | } | |
8efc0c15 | 51 | |
52 | /* Frees any data structures allocated for compression. */ | |
53 | ||
6ae2364d | 54 | void |
c52c7082 | 55 | buffer_compress_uninit(void) |
8efc0c15 | 56 | { |
5260325f | 57 | debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f", |
58 | outgoing_stream.total_in, outgoing_stream.total_out, | |
59 | outgoing_stream.total_in == 0 ? 0.0 : | |
60 | (double) outgoing_stream.total_out / outgoing_stream.total_in); | |
61 | debug("compress incoming: raw data %lu, compressed %lu, factor %.2f", | |
62 | incoming_stream.total_out, incoming_stream.total_in, | |
63 | incoming_stream.total_out == 0 ? 0.0 : | |
64 | (double) incoming_stream.total_in / incoming_stream.total_out); | |
6ba22c93 | 65 | if (compress_init_recv_called == 1) |
66 | inflateEnd(&incoming_stream); | |
67 | if (compress_init_send_called == 1) | |
68 | deflateEnd(&outgoing_stream); | |
8efc0c15 | 69 | } |
70 | ||
aa3378df | 71 | /* |
72 | * Compresses the contents of input_buffer into output_buffer. All packets | |
73 | * compressed using this function will form a single compressed data stream; | |
74 | * however, data will be flushed at the end of every call so that each | |
75 | * output_buffer can be decompressed independently (but in the appropriate | |
76 | * order since they together form a single compression stream) by the | |
77 | * receiver. This appends the compressed data to the output buffer. | |
78 | */ | |
8efc0c15 | 79 | |
6ae2364d | 80 | void |
5260325f | 81 | buffer_compress(Buffer * input_buffer, Buffer * output_buffer) |
8efc0c15 | 82 | { |
5260325f | 83 | char buf[4096]; |
84 | int status; | |
85 | ||
86 | /* This case is not handled below. */ | |
87 | if (buffer_len(input_buffer) == 0) | |
88 | return; | |
89 | ||
90 | /* Input is the contents of the input buffer. */ | |
1e3b8b07 | 91 | outgoing_stream.next_in = (u_char *) buffer_ptr(input_buffer); |
5260325f | 92 | outgoing_stream.avail_in = buffer_len(input_buffer); |
93 | ||
94 | /* Loop compressing until deflate() returns with avail_out != 0. */ | |
95 | do { | |
96 | /* Set up fixed-size output buffer. */ | |
1e3b8b07 | 97 | outgoing_stream.next_out = (u_char *)buf; |
5260325f | 98 | outgoing_stream.avail_out = sizeof(buf); |
99 | ||
100 | /* Compress as much data into the buffer as possible. */ | |
101 | status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH); | |
102 | switch (status) { | |
103 | case Z_OK: | |
104 | /* Append compressed data to output_buffer. */ | |
105 | buffer_append(output_buffer, buf, | |
7368a6c8 | 106 | sizeof(buf) - outgoing_stream.avail_out); |
5260325f | 107 | break; |
5260325f | 108 | default: |
109 | fatal("buffer_compress: deflate returned %d", status); | |
110 | /* NOTREACHED */ | |
111 | } | |
7368a6c8 | 112 | } while (outgoing_stream.avail_out == 0); |
8efc0c15 | 113 | } |
114 | ||
aa3378df | 115 | /* |
116 | * Uncompresses the contents of input_buffer into output_buffer. All packets | |
117 | * uncompressed using this function will form a single compressed data | |
118 | * stream; however, data will be flushed at the end of every call so that | |
119 | * each output_buffer. This must be called for the same size units that the | |
120 | * buffer_compress was called, and in the same order that buffers compressed | |
121 | * with that. This appends the uncompressed data to the output buffer. | |
122 | */ | |
8efc0c15 | 123 | |
6ae2364d | 124 | void |
5260325f | 125 | buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer) |
8efc0c15 | 126 | { |
5260325f | 127 | char buf[4096]; |
128 | int status; | |
129 | ||
1e3b8b07 | 130 | incoming_stream.next_in = (u_char *) buffer_ptr(input_buffer); |
5260325f | 131 | incoming_stream.avail_in = buffer_len(input_buffer); |
132 | ||
5260325f | 133 | for (;;) { |
7368a6c8 | 134 | /* Set up fixed-size output buffer. */ |
1e3b8b07 | 135 | incoming_stream.next_out = (u_char *) buf; |
7368a6c8 | 136 | incoming_stream.avail_out = sizeof(buf); |
137 | ||
5260325f | 138 | status = inflate(&incoming_stream, Z_PARTIAL_FLUSH); |
139 | switch (status) { | |
140 | case Z_OK: | |
141 | buffer_append(output_buffer, buf, | |
7368a6c8 | 142 | sizeof(buf) - incoming_stream.avail_out); |
5260325f | 143 | break; |
5260325f | 144 | case Z_BUF_ERROR: |
aa3378df | 145 | /* |
146 | * Comments in zlib.h say that we should keep calling | |
147 | * inflate() until we get an error. This appears to | |
148 | * be the error that we get. | |
149 | */ | |
5260325f | 150 | return; |
5260325f | 151 | default: |
152 | fatal("buffer_uncompress: inflate returned %d", status); | |
7368a6c8 | 153 | /* NOTREACHED */ |
5260325f | 154 | } |
8efc0c15 | 155 | } |
8efc0c15 | 156 | } |