Annotation of src/usr.bin/ssh/compress.c, Revision 1.6
1.1 deraadt 1: /*
1.3 deraadt 2: *
3: * compress.c
4: *
5: * Author: Tatu Ylonen <ylo@cs.hut.fi>
6: *
7: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: * All rights reserved
9: *
10: * Created: Wed Oct 25 22:12:46 1995 ylo
11: *
12: * Interface to packet compression for ssh.
13: *
14: */
1.1 deraadt 15:
16: #include "includes.h"
1.6 ! markus 17: RCSID("$Id: compress.c,v 1.6 2000/03/22 13:40:45 markus Exp $");
1.1 deraadt 18:
19: #include "ssh.h"
20: #include "buffer.h"
21: #include "zlib.h"
22:
23: static z_stream incoming_stream;
24: static z_stream outgoing_stream;
25:
1.4 markus 26: /*
27: * Initializes compression; level is compression level from 1 to 9
28: * (as in gzip).
29: */
1.1 deraadt 30:
1.2 markus 31: void
32: buffer_compress_init(int level)
1.1 deraadt 33: {
1.2 markus 34: debug("Enabling compression at level %d.", level);
35: if (level < 1 || level > 9)
36: fatal("Bad compression level %d.", level);
37: inflateInit(&incoming_stream);
38: deflateInit(&outgoing_stream, level);
1.1 deraadt 39: }
40:
41: /* Frees any data structures allocated for compression. */
42:
1.2 markus 43: void
44: buffer_compress_uninit()
1.1 deraadt 45: {
1.2 markus 46: debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
47: outgoing_stream.total_in, outgoing_stream.total_out,
48: outgoing_stream.total_in == 0 ? 0.0 :
49: (double) outgoing_stream.total_out / outgoing_stream.total_in);
50: debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
51: incoming_stream.total_out, incoming_stream.total_in,
52: incoming_stream.total_out == 0 ? 0.0 :
53: (double) incoming_stream.total_in / incoming_stream.total_out);
54: inflateEnd(&incoming_stream);
55: deflateEnd(&outgoing_stream);
1.1 deraadt 56: }
57:
1.4 markus 58: /*
59: * Compresses the contents of input_buffer into output_buffer. All packets
60: * compressed using this function will form a single compressed data stream;
61: * however, data will be flushed at the end of every call so that each
62: * output_buffer can be decompressed independently (but in the appropriate
63: * order since they together form a single compression stream) by the
64: * receiver. This appends the compressed data to the output buffer.
65: */
1.1 deraadt 66:
1.2 markus 67: void
68: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 69: {
1.2 markus 70: char buf[4096];
71: int status;
1.1 deraadt 72:
1.2 markus 73: /* This case is not handled below. */
74: if (buffer_len(input_buffer) == 0)
75: return;
76:
77: /* Input is the contents of the input buffer. */
1.5 markus 78: outgoing_stream.next_in = (unsigned char *) buffer_ptr(input_buffer);
1.2 markus 79: outgoing_stream.avail_in = buffer_len(input_buffer);
80:
81: /* Loop compressing until deflate() returns with avail_out != 0. */
82: do {
83: /* Set up fixed-size output buffer. */
1.5 markus 84: outgoing_stream.next_out = (unsigned char *)buf;
1.2 markus 85: outgoing_stream.avail_out = sizeof(buf);
86:
87: /* Compress as much data into the buffer as possible. */
88: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
89: switch (status) {
90: case Z_OK:
91: /* Append compressed data to output_buffer. */
92: buffer_append(output_buffer, buf,
1.6 ! markus 93: sizeof(buf) - outgoing_stream.avail_out);
1.2 markus 94: break;
95: default:
96: fatal("buffer_compress: deflate returned %d", status);
97: /* NOTREACHED */
98: }
1.6 ! markus 99: } while (outgoing_stream.avail_out == 0);
1.1 deraadt 100: }
101:
1.4 markus 102: /*
103: * Uncompresses the contents of input_buffer into output_buffer. All packets
104: * uncompressed using this function will form a single compressed data
105: * stream; however, data will be flushed at the end of every call so that
106: * each output_buffer. This must be called for the same size units that the
107: * buffer_compress was called, and in the same order that buffers compressed
108: * with that. This appends the uncompressed data to the output buffer.
109: */
1.1 deraadt 110:
1.2 markus 111: void
112: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 113: {
1.2 markus 114: char buf[4096];
115: int status;
1.1 deraadt 116:
1.5 markus 117: incoming_stream.next_in = (unsigned char *) buffer_ptr(input_buffer);
1.2 markus 118: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 119:
1.6 ! markus 120: for (;;) {
! 121: /* Set up fixed-size output buffer. */
! 122: incoming_stream.next_out = (unsigned char *) buf;
! 123: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 124:
1.2 markus 125: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
126: switch (status) {
127: case Z_OK:
128: buffer_append(output_buffer, buf,
1.6 ! markus 129: sizeof(buf) - incoming_stream.avail_out);
1.2 markus 130: break;
131: case Z_BUF_ERROR:
1.4 markus 132: /*
133: * Comments in zlib.h say that we should keep calling
134: * inflate() until we get an error. This appears to
135: * be the error that we get.
136: */
1.2 markus 137: return;
138: default:
139: fatal("buffer_uncompress: inflate returned %d", status);
1.6 ! markus 140: /* NOTREACHED */
1.2 markus 141: }
1.1 deraadt 142: }
143: }
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