Annotation of src/usr.bin/ssh/compress.c, Revision 1.15
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: *
1.9 deraadt 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"
1.15 ! markus 15: RCSID("$OpenBSD: compress.c,v 1.14 2001/04/05 10:39:01 markus Exp $");
1.1 deraadt 16:
1.12 markus 17: #include "log.h"
1.1 deraadt 18: #include "buffer.h"
19: #include "zlib.h"
1.13 itojun 20: #include "compress.h"
1.1 deraadt 21:
22: static z_stream incoming_stream;
23: static z_stream outgoing_stream;
1.14 markus 24: static int compress_init_send_called = 0;
25: static int compress_init_recv_called = 0;
1.1 deraadt 26:
1.4 markus 27: /*
28: * Initializes compression; level is compression level from 1 to 9
29: * (as in gzip).
30: */
1.1 deraadt 31:
1.7 markus 32: void
1.14 markus 33: buffer_compress_init_send(int level)
1.1 deraadt 34: {
1.14 markus 35: if (compress_init_send_called == 1)
1.15 ! markus 36: deflateEnd(&outgoing_stream);
1.14 markus 37: compress_init_send_called = 1;
1.2 markus 38: debug("Enabling compression at level %d.", level);
39: if (level < 1 || level > 9)
40: fatal("Bad compression level %d.", level);
1.14 markus 41: deflateInit(&outgoing_stream, level);
42: }
43: void
44: buffer_compress_init_recv(void)
45: {
46: if (compress_init_recv_called == 1)
47: inflateEnd(&incoming_stream);
48: compress_init_recv_called = 1;
1.2 markus 49: inflateInit(&incoming_stream);
1.1 deraadt 50: }
51:
52: /* Frees any data structures allocated for compression. */
53:
1.7 markus 54: void
1.11 markus 55: buffer_compress_uninit(void)
1.1 deraadt 56: {
1.2 markus 57: debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
58: outgoing_stream.total_in, outgoing_stream.total_out,
59: outgoing_stream.total_in == 0 ? 0.0 :
60: (double) outgoing_stream.total_out / outgoing_stream.total_in);
61: debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
62: incoming_stream.total_out, incoming_stream.total_in,
63: incoming_stream.total_out == 0 ? 0.0 :
64: (double) incoming_stream.total_in / incoming_stream.total_out);
1.14 markus 65: if (compress_init_recv_called == 1)
66: inflateEnd(&incoming_stream);
67: if (compress_init_send_called == 1)
68: deflateEnd(&outgoing_stream);
1.1 deraadt 69: }
70:
1.4 markus 71: /*
72: * Compresses the contents of input_buffer into output_buffer. All packets
73: * compressed using this function will form a single compressed data stream;
74: * however, data will be flushed at the end of every call so that each
75: * output_buffer can be decompressed independently (but in the appropriate
76: * order since they together form a single compression stream) by the
77: * receiver. This appends the compressed data to the output buffer.
78: */
1.1 deraadt 79:
1.7 markus 80: void
1.2 markus 81: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 82: {
1.2 markus 83: char buf[4096];
84: int status;
1.1 deraadt 85:
1.2 markus 86: /* This case is not handled below. */
87: if (buffer_len(input_buffer) == 0)
88: return;
89:
90: /* Input is the contents of the input buffer. */
1.10 markus 91: outgoing_stream.next_in = (u_char *) buffer_ptr(input_buffer);
1.2 markus 92: outgoing_stream.avail_in = buffer_len(input_buffer);
93:
94: /* Loop compressing until deflate() returns with avail_out != 0. */
95: do {
96: /* Set up fixed-size output buffer. */
1.10 markus 97: outgoing_stream.next_out = (u_char *)buf;
1.2 markus 98: outgoing_stream.avail_out = sizeof(buf);
99:
100: /* Compress as much data into the buffer as possible. */
101: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
102: switch (status) {
103: case Z_OK:
104: /* Append compressed data to output_buffer. */
105: buffer_append(output_buffer, buf,
1.6 markus 106: sizeof(buf) - outgoing_stream.avail_out);
1.2 markus 107: break;
108: default:
109: fatal("buffer_compress: deflate returned %d", status);
110: /* NOTREACHED */
111: }
1.6 markus 112: } while (outgoing_stream.avail_out == 0);
1.1 deraadt 113: }
114:
1.4 markus 115: /*
116: * Uncompresses the contents of input_buffer into output_buffer. All packets
117: * uncompressed using this function will form a single compressed data
118: * stream; however, data will be flushed at the end of every call so that
119: * each output_buffer. This must be called for the same size units that the
120: * buffer_compress was called, and in the same order that buffers compressed
121: * with that. This appends the uncompressed data to the output buffer.
122: */
1.1 deraadt 123:
1.7 markus 124: void
1.2 markus 125: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 126: {
1.2 markus 127: char buf[4096];
128: int status;
1.1 deraadt 129:
1.10 markus 130: incoming_stream.next_in = (u_char *) buffer_ptr(input_buffer);
1.2 markus 131: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 132:
1.6 markus 133: for (;;) {
134: /* Set up fixed-size output buffer. */
1.10 markus 135: incoming_stream.next_out = (u_char *) buf;
1.6 markus 136: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 137:
1.2 markus 138: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
139: switch (status) {
140: case Z_OK:
141: buffer_append(output_buffer, buf,
1.6 markus 142: sizeof(buf) - incoming_stream.avail_out);
1.2 markus 143: break;
144: case Z_BUF_ERROR:
1.4 markus 145: /*
146: * Comments in zlib.h say that we should keep calling
147: * inflate() until we get an error. This appears to
148: * be the error that we get.
149: */
1.2 markus 150: return;
151: default:
152: fatal("buffer_uncompress: inflate returned %d", status);
1.6 markus 153: /* NOTREACHED */
1.2 markus 154: }
1.1 deraadt 155: }
156: }
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