1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * Author: Tatu Ylonen <ylo@cs.hut.fi>
3*0Sstevel@tonic-gate * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4*0Sstevel@tonic-gate * All rights reserved
5*0Sstevel@tonic-gate * Interface to packet compression for ssh.
6*0Sstevel@tonic-gate *
7*0Sstevel@tonic-gate * As far as I am concerned, the code I have written for this software
8*0Sstevel@tonic-gate * can be used freely for any purpose. Any derived versions of this
9*0Sstevel@tonic-gate * software must be clearly marked as such, and if the derived work is
10*0Sstevel@tonic-gate * incompatible with the protocol description in the RFC file, it must be
11*0Sstevel@tonic-gate * called by a name other than "ssh" or "Secure Shell".
12*0Sstevel@tonic-gate */
13*0Sstevel@tonic-gate
14*0Sstevel@tonic-gate #include "includes.h"
15*0Sstevel@tonic-gate RCSID("$OpenBSD: compress.c,v 1.19 2002/03/18 17:31:54 provos Exp $");
16*0Sstevel@tonic-gate
17*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
18*0Sstevel@tonic-gate
19*0Sstevel@tonic-gate #include "log.h"
20*0Sstevel@tonic-gate #include "buffer.h"
21*0Sstevel@tonic-gate #include "zlib.h"
22*0Sstevel@tonic-gate #include "compress.h"
23*0Sstevel@tonic-gate
24*0Sstevel@tonic-gate z_stream incoming_stream;
25*0Sstevel@tonic-gate z_stream outgoing_stream;
26*0Sstevel@tonic-gate static int compress_init_send_called = 0;
27*0Sstevel@tonic-gate static int compress_init_recv_called = 0;
28*0Sstevel@tonic-gate static int inflate_failed = 0;
29*0Sstevel@tonic-gate static int deflate_failed = 0;
30*0Sstevel@tonic-gate
31*0Sstevel@tonic-gate /*
32*0Sstevel@tonic-gate * Initializes compression; level is compression level from 1 to 9
33*0Sstevel@tonic-gate * (as in gzip).
34*0Sstevel@tonic-gate */
35*0Sstevel@tonic-gate
36*0Sstevel@tonic-gate void
buffer_compress_init_send(int level)37*0Sstevel@tonic-gate buffer_compress_init_send(int level)
38*0Sstevel@tonic-gate {
39*0Sstevel@tonic-gate if (compress_init_send_called == 1)
40*0Sstevel@tonic-gate deflateEnd(&outgoing_stream);
41*0Sstevel@tonic-gate compress_init_send_called = 1;
42*0Sstevel@tonic-gate debug("Enabling compression at level %d.", level);
43*0Sstevel@tonic-gate if (level < 1 || level > 9)
44*0Sstevel@tonic-gate fatal("Bad compression level %d.", level);
45*0Sstevel@tonic-gate deflateInit(&outgoing_stream, level);
46*0Sstevel@tonic-gate }
47*0Sstevel@tonic-gate void
buffer_compress_init_recv(void)48*0Sstevel@tonic-gate buffer_compress_init_recv(void)
49*0Sstevel@tonic-gate {
50*0Sstevel@tonic-gate if (compress_init_recv_called == 1)
51*0Sstevel@tonic-gate inflateEnd(&incoming_stream);
52*0Sstevel@tonic-gate compress_init_recv_called = 1;
53*0Sstevel@tonic-gate inflateInit(&incoming_stream);
54*0Sstevel@tonic-gate }
55*0Sstevel@tonic-gate
56*0Sstevel@tonic-gate /* Frees any data structures allocated for compression. */
57*0Sstevel@tonic-gate
58*0Sstevel@tonic-gate void
buffer_compress_uninit(void)59*0Sstevel@tonic-gate buffer_compress_uninit(void)
60*0Sstevel@tonic-gate {
61*0Sstevel@tonic-gate debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
62*0Sstevel@tonic-gate outgoing_stream.total_in, outgoing_stream.total_out,
63*0Sstevel@tonic-gate outgoing_stream.total_in == 0 ? 0.0 :
64*0Sstevel@tonic-gate (double) outgoing_stream.total_out / outgoing_stream.total_in);
65*0Sstevel@tonic-gate debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
66*0Sstevel@tonic-gate incoming_stream.total_out, incoming_stream.total_in,
67*0Sstevel@tonic-gate incoming_stream.total_out == 0 ? 0.0 :
68*0Sstevel@tonic-gate (double) incoming_stream.total_in / incoming_stream.total_out);
69*0Sstevel@tonic-gate if (compress_init_recv_called == 1 && inflate_failed == 0)
70*0Sstevel@tonic-gate inflateEnd(&incoming_stream);
71*0Sstevel@tonic-gate if (compress_init_send_called == 1 && deflate_failed == 0)
72*0Sstevel@tonic-gate deflateEnd(&outgoing_stream);
73*0Sstevel@tonic-gate }
74*0Sstevel@tonic-gate
75*0Sstevel@tonic-gate /*
76*0Sstevel@tonic-gate * Compresses the contents of input_buffer into output_buffer. All packets
77*0Sstevel@tonic-gate * compressed using this function will form a single compressed data stream;
78*0Sstevel@tonic-gate * however, data will be flushed at the end of every call so that each
79*0Sstevel@tonic-gate * output_buffer can be decompressed independently (but in the appropriate
80*0Sstevel@tonic-gate * order since they together form a single compression stream) by the
81*0Sstevel@tonic-gate * receiver. This appends the compressed data to the output buffer.
82*0Sstevel@tonic-gate */
83*0Sstevel@tonic-gate
84*0Sstevel@tonic-gate void
buffer_compress(Buffer * input_buffer,Buffer * output_buffer)85*0Sstevel@tonic-gate buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
86*0Sstevel@tonic-gate {
87*0Sstevel@tonic-gate u_char buf[4096];
88*0Sstevel@tonic-gate int status;
89*0Sstevel@tonic-gate
90*0Sstevel@tonic-gate /* This case is not handled below. */
91*0Sstevel@tonic-gate if (buffer_len(input_buffer) == 0)
92*0Sstevel@tonic-gate return;
93*0Sstevel@tonic-gate
94*0Sstevel@tonic-gate /* Input is the contents of the input buffer. */
95*0Sstevel@tonic-gate outgoing_stream.next_in = buffer_ptr(input_buffer);
96*0Sstevel@tonic-gate outgoing_stream.avail_in = buffer_len(input_buffer);
97*0Sstevel@tonic-gate
98*0Sstevel@tonic-gate /* Loop compressing until deflate() returns with avail_out != 0. */
99*0Sstevel@tonic-gate do {
100*0Sstevel@tonic-gate /* Set up fixed-size output buffer. */
101*0Sstevel@tonic-gate outgoing_stream.next_out = buf;
102*0Sstevel@tonic-gate outgoing_stream.avail_out = sizeof(buf);
103*0Sstevel@tonic-gate
104*0Sstevel@tonic-gate /* Compress as much data into the buffer as possible. */
105*0Sstevel@tonic-gate status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
106*0Sstevel@tonic-gate switch (status) {
107*0Sstevel@tonic-gate case Z_OK:
108*0Sstevel@tonic-gate /* Append compressed data to output_buffer. */
109*0Sstevel@tonic-gate buffer_append(output_buffer, buf,
110*0Sstevel@tonic-gate sizeof(buf) - outgoing_stream.avail_out);
111*0Sstevel@tonic-gate break;
112*0Sstevel@tonic-gate default:
113*0Sstevel@tonic-gate deflate_failed = 1;
114*0Sstevel@tonic-gate fatal("buffer_compress: deflate returned %d", status);
115*0Sstevel@tonic-gate /* NOTREACHED */
116*0Sstevel@tonic-gate }
117*0Sstevel@tonic-gate } while (outgoing_stream.avail_out == 0);
118*0Sstevel@tonic-gate }
119*0Sstevel@tonic-gate
120*0Sstevel@tonic-gate /*
121*0Sstevel@tonic-gate * Uncompresses the contents of input_buffer into output_buffer. All packets
122*0Sstevel@tonic-gate * uncompressed using this function will form a single compressed data
123*0Sstevel@tonic-gate * stream; however, data will be flushed at the end of every call so that
124*0Sstevel@tonic-gate * each output_buffer. This must be called for the same size units that the
125*0Sstevel@tonic-gate * buffer_compress was called, and in the same order that buffers compressed
126*0Sstevel@tonic-gate * with that. This appends the uncompressed data to the output buffer.
127*0Sstevel@tonic-gate */
128*0Sstevel@tonic-gate
129*0Sstevel@tonic-gate void
buffer_uncompress(Buffer * input_buffer,Buffer * output_buffer)130*0Sstevel@tonic-gate buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
131*0Sstevel@tonic-gate {
132*0Sstevel@tonic-gate u_char buf[4096];
133*0Sstevel@tonic-gate int status;
134*0Sstevel@tonic-gate
135*0Sstevel@tonic-gate incoming_stream.next_in = buffer_ptr(input_buffer);
136*0Sstevel@tonic-gate incoming_stream.avail_in = buffer_len(input_buffer);
137*0Sstevel@tonic-gate
138*0Sstevel@tonic-gate for (;;) {
139*0Sstevel@tonic-gate /* Set up fixed-size output buffer. */
140*0Sstevel@tonic-gate incoming_stream.next_out = buf;
141*0Sstevel@tonic-gate incoming_stream.avail_out = sizeof(buf);
142*0Sstevel@tonic-gate
143*0Sstevel@tonic-gate status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
144*0Sstevel@tonic-gate switch (status) {
145*0Sstevel@tonic-gate case Z_OK:
146*0Sstevel@tonic-gate buffer_append(output_buffer, buf,
147*0Sstevel@tonic-gate sizeof(buf) - incoming_stream.avail_out);
148*0Sstevel@tonic-gate break;
149*0Sstevel@tonic-gate case Z_BUF_ERROR:
150*0Sstevel@tonic-gate /*
151*0Sstevel@tonic-gate * Comments in zlib.h say that we should keep calling
152*0Sstevel@tonic-gate * inflate() until we get an error. This appears to
153*0Sstevel@tonic-gate * be the error that we get.
154*0Sstevel@tonic-gate */
155*0Sstevel@tonic-gate return;
156*0Sstevel@tonic-gate default:
157*0Sstevel@tonic-gate inflate_failed = 1;
158*0Sstevel@tonic-gate fatal("buffer_uncompress: inflate returned %d", status);
159*0Sstevel@tonic-gate /* NOTREACHED */
160*0Sstevel@tonic-gate }
161*0Sstevel@tonic-gate }
162*0Sstevel@tonic-gate }
163