Branch data Line data Source code
1 : : /* $OpenBSD: compress.c,v 1.26 2010/09/08 04:13:31 deraadt Exp $ */
2 : : /*
3 : : * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 : : * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 : : * All rights reserved
6 : : * Interface to packet compression for ssh.
7 : : *
8 : : * As far as I am concerned, the code I have written for this software
9 : : * can be used freely for any purpose. Any derived versions of this
10 : : * software must be clearly marked as such, and if the derived work is
11 : : * incompatible with the protocol description in the RFC file, it must be
12 : : * called by a name other than "ssh" or "Secure Shell".
13 : : */
14 : :
15 : : #include "includes.h"
16 : :
17 : : #include <sys/types.h>
18 : :
19 : : #include <stdarg.h>
20 : :
21 : : #include "log.h"
22 : : #include "buffer.h"
23 : : #include "compress.h"
24 : :
25 : : #include <zlib.h>
26 : :
27 : : z_stream incoming_stream;
28 : : z_stream outgoing_stream;
29 : : static int compress_init_send_called = 0;
30 : : static int compress_init_recv_called = 0;
31 : : static int inflate_failed = 0;
32 : : static int deflate_failed = 0;
33 : :
34 : : /*
35 : : * Initializes compression; level is compression level from 1 to 9
36 : : * (as in gzip).
37 : : */
38 : :
39 : : void
40 : 0 : buffer_compress_init_send(int level)
41 : : {
42 [ # # ]: 0 : if (compress_init_send_called == 1)
43 : 0 : deflateEnd(&outgoing_stream);
44 : 0 : compress_init_send_called = 1;
45 : 0 : debug("Enabling compression at level %d.", level);
46 [ # # ]: 0 : if (level < 1 || level > 9)
47 : 0 : fatal("Bad compression level %d.", level);
48 : 0 : deflateInit(&outgoing_stream, level);
49 : 0 : }
50 : : void
51 : 0 : buffer_compress_init_recv(void)
52 : : {
53 [ # # ]: 0 : if (compress_init_recv_called == 1)
54 : 0 : inflateEnd(&incoming_stream);
55 : 0 : compress_init_recv_called = 1;
56 : 0 : inflateInit(&incoming_stream);
57 : 0 : }
58 : :
59 : : /* Frees any data structures allocated for compression. */
60 : :
61 : : void
62 : 0 : buffer_compress_uninit(void)
63 : : {
64 [ # # ]: 0 : debug("compress outgoing: raw data %llu, compressed %llu, factor %.2f",
65 : : (unsigned long long)outgoing_stream.total_in,
66 : 0 : (unsigned long long)outgoing_stream.total_out,
67 : 0 : outgoing_stream.total_in == 0 ? 0.0 :
68 : 0 : (double) outgoing_stream.total_out / outgoing_stream.total_in);
69 [ # # ]: 0 : debug("compress incoming: raw data %llu, compressed %llu, factor %.2f",
70 : : (unsigned long long)incoming_stream.total_out,
71 : 0 : (unsigned long long)incoming_stream.total_in,
72 : 0 : incoming_stream.total_out == 0 ? 0.0 :
73 : 0 : (double) incoming_stream.total_in / incoming_stream.total_out);
74 [ # # ][ # # ]: 0 : if (compress_init_recv_called == 1 && inflate_failed == 0)
75 : 0 : inflateEnd(&incoming_stream);
76 [ # # ][ # # ]: 0 : if (compress_init_send_called == 1 && deflate_failed == 0)
77 : 0 : deflateEnd(&outgoing_stream);
78 : 0 : }
79 : :
80 : : /*
81 : : * Compresses the contents of input_buffer into output_buffer. All packets
82 : : * compressed using this function will form a single compressed data stream;
83 : : * however, data will be flushed at the end of every call so that each
84 : : * output_buffer can be decompressed independently (but in the appropriate
85 : : * order since they together form a single compression stream) by the
86 : : * receiver. This appends the compressed data to the output buffer.
87 : : */
88 : :
89 : : void
90 : 0 : buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
91 : : {
92 : : u_char buf[4096];
93 : : int status;
94 : :
95 : : /* This case is not handled below. */
96 [ # # ]: 0 : if (buffer_len(input_buffer) == 0)
97 : 0 : return;
98 : :
99 : : /* Input is the contents of the input buffer. */
100 : 0 : outgoing_stream.next_in = buffer_ptr(input_buffer);
101 : 0 : outgoing_stream.avail_in = buffer_len(input_buffer);
102 : :
103 : : /* Loop compressing until deflate() returns with avail_out != 0. */
104 : : do {
105 : : /* Set up fixed-size output buffer. */
106 : 0 : outgoing_stream.next_out = buf;
107 : 0 : outgoing_stream.avail_out = sizeof(buf);
108 : :
109 : : /* Compress as much data into the buffer as possible. */
110 : 0 : status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
111 [ # # ]: 0 : switch (status) {
112 : : case Z_OK:
113 : : /* Append compressed data to output_buffer. */
114 : 0 : buffer_append(output_buffer, buf,
115 : 0 : sizeof(buf) - outgoing_stream.avail_out);
116 : : break;
117 : : default:
118 : 0 : deflate_failed = 1;
119 : 0 : fatal("buffer_compress: deflate returned %d", status);
120 : : /* NOTREACHED */
121 : : }
122 [ # # ]: 0 : } while (outgoing_stream.avail_out == 0);
123 : : }
124 : :
125 : : /*
126 : : * Uncompresses the contents of input_buffer into output_buffer. All packets
127 : : * uncompressed using this function will form a single compressed data
128 : : * stream; however, data will be flushed at the end of every call so that
129 : : * each output_buffer. This must be called for the same size units that the
130 : : * buffer_compress was called, and in the same order that buffers compressed
131 : : * with that. This appends the uncompressed data to the output buffer.
132 : : */
133 : :
134 : : void
135 : 0 : buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
136 : : {
137 : : u_char buf[4096];
138 : : int status;
139 : :
140 : 0 : incoming_stream.next_in = buffer_ptr(input_buffer);
141 : 0 : incoming_stream.avail_in = buffer_len(input_buffer);
142 : :
143 : : for (;;) {
144 : : /* Set up fixed-size output buffer. */
145 : 0 : incoming_stream.next_out = buf;
146 : 0 : incoming_stream.avail_out = sizeof(buf);
147 : :
148 : 0 : status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
149 [ # # # ]: 0 : switch (status) {
150 : : case Z_OK:
151 : 0 : buffer_append(output_buffer, buf,
152 : 0 : sizeof(buf) - incoming_stream.avail_out);
153 : : break;
154 : : case Z_BUF_ERROR:
155 : : /*
156 : : * Comments in zlib.h say that we should keep calling
157 : : * inflate() until we get an error. This appears to
158 : : * be the error that we get.
159 : : */
160 : 0 : return;
161 : : default:
162 : 0 : inflate_failed = 1;
163 : 0 : fatal("buffer_uncompress: inflate returned %d", status);
164 : : /* NOTREACHED */
165 : : }
166 : 0 : }
167 : : }
|
