Annotation of src/usr.bin/ssh/compress.c, Revision 1.3
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"
1.3 ! deraadt 17: RCSID("$Id: compress.c,v 1.2 1999/11/23 22:25:53 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:
1.2 markus 26: /* Initializes compression; level is compression level from 1 to 9
27: (as in gzip). */
1.1 deraadt 28:
1.2 markus 29: void
30: buffer_compress_init(int level)
1.1 deraadt 31: {
1.2 markus 32: debug("Enabling compression at level %d.", level);
33: if (level < 1 || level > 9)
34: fatal("Bad compression level %d.", level);
35: inflateInit(&incoming_stream);
36: deflateInit(&outgoing_stream, level);
1.1 deraadt 37: }
38:
39: /* Frees any data structures allocated for compression. */
40:
1.2 markus 41: void
42: buffer_compress_uninit()
1.1 deraadt 43: {
1.2 markus 44: debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
45: outgoing_stream.total_in, outgoing_stream.total_out,
46: outgoing_stream.total_in == 0 ? 0.0 :
47: (double) outgoing_stream.total_out / outgoing_stream.total_in);
48: debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
49: incoming_stream.total_out, incoming_stream.total_in,
50: incoming_stream.total_out == 0 ? 0.0 :
51: (double) incoming_stream.total_in / incoming_stream.total_out);
52: inflateEnd(&incoming_stream);
53: deflateEnd(&outgoing_stream);
1.1 deraadt 54: }
55:
56: /* Compresses the contents of input_buffer into output_buffer. All
57: packets compressed using this function will form a single
58: compressed data stream; however, data will be flushed at the end of
59: every call so that each output_buffer can be decompressed
60: independently (but in the appropriate order since they together
61: form a single compression stream) by the receiver. This appends
62: the compressed data to the output buffer. */
63:
1.2 markus 64: void
65: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 66: {
1.2 markus 67: char buf[4096];
68: int status;
1.1 deraadt 69:
1.2 markus 70: /* This case is not handled below. */
71: if (buffer_len(input_buffer) == 0)
72: return;
73:
74: /* Input is the contents of the input buffer. */
75: outgoing_stream.next_in = buffer_ptr(input_buffer);
76: outgoing_stream.avail_in = buffer_len(input_buffer);
77:
78: /* Loop compressing until deflate() returns with avail_out != 0. */
79: do {
80: /* Set up fixed-size output buffer. */
81: outgoing_stream.next_out = buf;
82: outgoing_stream.avail_out = sizeof(buf);
83:
84: /* Compress as much data into the buffer as possible. */
85: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
86: switch (status) {
87: case Z_OK:
88: /* Append compressed data to output_buffer. */
89: buffer_append(output_buffer, buf,
90: sizeof(buf) - outgoing_stream.avail_out);
91: break;
92: case Z_STREAM_END:
93: fatal("buffer_compress: deflate returned Z_STREAM_END");
94: /* NOTREACHED */
95: case Z_STREAM_ERROR:
96: fatal("buffer_compress: deflate returned Z_STREAM_ERROR");
97: /* NOTREACHED */
98: case Z_BUF_ERROR:
99: fatal("buffer_compress: deflate returned Z_BUF_ERROR");
100: /* NOTREACHED */
101: default:
102: fatal("buffer_compress: deflate returned %d", status);
103: /* NOTREACHED */
104: }
1.1 deraadt 105: }
1.2 markus 106: while (outgoing_stream.avail_out == 0);
1.1 deraadt 107: }
108:
109: /* Uncompresses the contents of input_buffer into output_buffer. All
110: packets uncompressed using this function will form a single
111: compressed data stream; however, data will be flushed at the end of
112: every call so that each output_buffer. This must be called for the
113: same size units that the buffer_compress was called, and in the
114: same order that buffers compressed with that. This appends the
115: uncompressed data to the output buffer. */
116:
1.2 markus 117: void
118: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 119: {
1.2 markus 120: char buf[4096];
121: int status;
1.1 deraadt 122:
1.2 markus 123: incoming_stream.next_in = buffer_ptr(input_buffer);
124: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 125:
1.2 markus 126: incoming_stream.next_out = buf;
127: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 128:
1.2 markus 129: for (;;) {
130: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
131: switch (status) {
132: case Z_OK:
133: buffer_append(output_buffer, buf,
134: sizeof(buf) - incoming_stream.avail_out);
135: incoming_stream.next_out = buf;
136: incoming_stream.avail_out = sizeof(buf);
137: break;
138: case Z_STREAM_END:
139: fatal("buffer_uncompress: inflate returned Z_STREAM_END");
140: /* NOTREACHED */
141: case Z_DATA_ERROR:
142: fatal("buffer_uncompress: inflate returned Z_DATA_ERROR");
143: /* NOTREACHED */
144: case Z_STREAM_ERROR:
145: fatal("buffer_uncompress: inflate returned Z_STREAM_ERROR");
146: /* NOTREACHED */
147: case Z_BUF_ERROR:
148: /* Comments in zlib.h say that we should keep
149: calling inflate() until we get an error. This
150: appears to be the error that we get. */
151: return;
152: case Z_MEM_ERROR:
153: fatal("buffer_uncompress: inflate returned Z_MEM_ERROR");
154: /* NOTREACHED */
155: default:
156: fatal("buffer_uncompress: inflate returned %d", status);
157: }
1.1 deraadt 158: }
159: }
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