Annotation of src/usr.bin/ssh/compress.c, Revision 1.7.2.3
1.1 deraadt 1: /*
1.3 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
5: * Interface to packet compression for ssh.
1.7 markus 6: *
1.7.2.2 jason 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".
1.3 deraadt 12: */
1.1 deraadt 13:
14: #include "includes.h"
1.7.2.3 ! jason 15: RCSID("$OpenBSD: compress.c,v 1.13 2001/02/08 19:30:51 itojun Exp $");
1.1 deraadt 16:
1.7.2.3 ! jason 17: #include "log.h"
1.1 deraadt 18: #include "buffer.h"
19: #include "zlib.h"
1.7.2.3 ! jason 20: #include "compress.h"
1.1 deraadt 21:
22: static z_stream incoming_stream;
23: static z_stream outgoing_stream;
24:
1.4 markus 25: /*
26: * Initializes compression; level is compression level from 1 to 9
27: * (as in gzip).
28: */
1.1 deraadt 29:
1.7 markus 30: void
1.2 markus 31: buffer_compress_init(int level)
1.1 deraadt 32: {
1.2 markus 33: debug("Enabling compression at level %d.", level);
34: if (level < 1 || level > 9)
35: fatal("Bad compression level %d.", level);
36: inflateInit(&incoming_stream);
37: deflateInit(&outgoing_stream, level);
1.1 deraadt 38: }
39:
40: /* Frees any data structures allocated for compression. */
41:
1.7 markus 42: void
1.7.2.3 ! jason 43: buffer_compress_uninit(void)
1.1 deraadt 44: {
1.2 markus 45: debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
46: outgoing_stream.total_in, outgoing_stream.total_out,
47: outgoing_stream.total_in == 0 ? 0.0 :
48: (double) outgoing_stream.total_out / outgoing_stream.total_in);
49: debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
50: incoming_stream.total_out, incoming_stream.total_in,
51: incoming_stream.total_out == 0 ? 0.0 :
52: (double) incoming_stream.total_in / incoming_stream.total_out);
53: inflateEnd(&incoming_stream);
54: deflateEnd(&outgoing_stream);
1.1 deraadt 55: }
56:
1.4 markus 57: /*
58: * Compresses the contents of input_buffer into output_buffer. All packets
59: * compressed using this function will form a single compressed data stream;
60: * however, data will be flushed at the end of every call so that each
61: * output_buffer can be decompressed independently (but in the appropriate
62: * order since they together form a single compression stream) by the
63: * receiver. This appends the compressed data to the output buffer.
64: */
1.1 deraadt 65:
1.7 markus 66: void
1.2 markus 67: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 68: {
1.2 markus 69: char buf[4096];
70: int status;
1.1 deraadt 71:
1.2 markus 72: /* This case is not handled below. */
73: if (buffer_len(input_buffer) == 0)
74: return;
75:
76: /* Input is the contents of the input buffer. */
1.7.2.3 ! jason 77: outgoing_stream.next_in = (u_char *) buffer_ptr(input_buffer);
1.2 markus 78: outgoing_stream.avail_in = buffer_len(input_buffer);
79:
80: /* Loop compressing until deflate() returns with avail_out != 0. */
81: do {
82: /* Set up fixed-size output buffer. */
1.7.2.3 ! jason 83: outgoing_stream.next_out = (u_char *)buf;
1.2 markus 84: outgoing_stream.avail_out = sizeof(buf);
85:
86: /* Compress as much data into the buffer as possible. */
87: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
88: switch (status) {
89: case Z_OK:
90: /* Append compressed data to output_buffer. */
91: buffer_append(output_buffer, buf,
1.6 markus 92: sizeof(buf) - outgoing_stream.avail_out);
1.2 markus 93: break;
94: default:
95: fatal("buffer_compress: deflate returned %d", status);
96: /* NOTREACHED */
97: }
1.6 markus 98: } while (outgoing_stream.avail_out == 0);
1.1 deraadt 99: }
100:
1.4 markus 101: /*
102: * Uncompresses the contents of input_buffer into output_buffer. All packets
103: * uncompressed using this function will form a single compressed data
104: * stream; however, data will be flushed at the end of every call so that
105: * each output_buffer. This must be called for the same size units that the
106: * buffer_compress was called, and in the same order that buffers compressed
107: * with that. This appends the uncompressed data to the output buffer.
108: */
1.1 deraadt 109:
1.7 markus 110: void
1.2 markus 111: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 112: {
1.2 markus 113: char buf[4096];
114: int status;
1.1 deraadt 115:
1.7.2.3 ! jason 116: incoming_stream.next_in = (u_char *) buffer_ptr(input_buffer);
1.2 markus 117: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 118:
1.6 markus 119: for (;;) {
120: /* Set up fixed-size output buffer. */
1.7.2.3 ! jason 121: incoming_stream.next_out = (u_char *) buf;
1.6 markus 122: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 123:
1.2 markus 124: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
125: switch (status) {
126: case Z_OK:
127: buffer_append(output_buffer, buf,
1.6 markus 128: sizeof(buf) - incoming_stream.avail_out);
1.2 markus 129: break;
130: case Z_BUF_ERROR:
1.4 markus 131: /*
132: * Comments in zlib.h say that we should keep calling
133: * inflate() until we get an error. This appears to
134: * be the error that we get.
135: */
1.2 markus 136: return;
137: default:
138: fatal("buffer_uncompress: inflate returned %d", status);
1.6 markus 139: /* NOTREACHED */
1.2 markus 140: }
1.1 deraadt 141: }
142: }
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