Annotation of src/usr.bin/ssh/compress.c, Revision 1.20
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"
1.20 ! markus 15: RCSID("$OpenBSD: compress.c,v 1.19 2002/03/18 17:31:54 provos 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:
1.19 provos 22: z_stream incoming_stream;
23: z_stream outgoing_stream;
1.14 markus 24: static int compress_init_send_called = 0;
25: static int compress_init_recv_called = 0;
1.18 markus 26: static int inflate_failed = 0;
27: static int deflate_failed = 0;
1.1 deraadt 28:
1.4 markus 29: /*
30: * Initializes compression; level is compression level from 1 to 9
31: * (as in gzip).
32: */
1.1 deraadt 33:
1.7 markus 34: void
1.14 markus 35: buffer_compress_init_send(int level)
1.1 deraadt 36: {
1.14 markus 37: if (compress_init_send_called == 1)
1.15 markus 38: deflateEnd(&outgoing_stream);
1.14 markus 39: compress_init_send_called = 1;
1.2 markus 40: debug("Enabling compression at level %d.", level);
41: if (level < 1 || level > 9)
42: fatal("Bad compression level %d.", level);
1.14 markus 43: deflateInit(&outgoing_stream, level);
44: }
45: void
46: buffer_compress_init_recv(void)
47: {
48: if (compress_init_recv_called == 1)
49: inflateEnd(&incoming_stream);
50: compress_init_recv_called = 1;
1.2 markus 51: inflateInit(&incoming_stream);
1.1 deraadt 52: }
53:
54: /* Frees any data structures allocated for compression. */
55:
1.7 markus 56: void
1.11 markus 57: buffer_compress_uninit(void)
1.1 deraadt 58: {
1.20 ! markus 59: debug("compress outgoing: raw data %llu, compressed %llu, factor %.2f",
1.16 deraadt 60: outgoing_stream.total_in, outgoing_stream.total_out,
61: outgoing_stream.total_in == 0 ? 0.0 :
62: (double) outgoing_stream.total_out / outgoing_stream.total_in);
1.20 ! markus 63: debug("compress incoming: raw data %llu, compressed %llu, factor %.2f",
1.16 deraadt 64: incoming_stream.total_out, incoming_stream.total_in,
65: incoming_stream.total_out == 0 ? 0.0 :
66: (double) incoming_stream.total_in / incoming_stream.total_out);
1.18 markus 67: if (compress_init_recv_called == 1 && inflate_failed == 0)
1.14 markus 68: inflateEnd(&incoming_stream);
1.18 markus 69: if (compress_init_send_called == 1 && deflate_failed == 0)
1.14 markus 70: deflateEnd(&outgoing_stream);
1.1 deraadt 71: }
72:
1.4 markus 73: /*
74: * Compresses the contents of input_buffer into output_buffer. All packets
75: * compressed using this function will form a single compressed data stream;
76: * however, data will be flushed at the end of every call so that each
77: * output_buffer can be decompressed independently (but in the appropriate
78: * order since they together form a single compression stream) by the
79: * receiver. This appends the compressed data to the output buffer.
80: */
1.1 deraadt 81:
1.7 markus 82: void
1.2 markus 83: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 84: {
1.17 stevesk 85: u_char buf[4096];
1.2 markus 86: int status;
1.1 deraadt 87:
1.2 markus 88: /* This case is not handled below. */
89: if (buffer_len(input_buffer) == 0)
90: return;
91:
92: /* Input is the contents of the input buffer. */
1.17 stevesk 93: outgoing_stream.next_in = buffer_ptr(input_buffer);
1.2 markus 94: outgoing_stream.avail_in = buffer_len(input_buffer);
95:
96: /* Loop compressing until deflate() returns with avail_out != 0. */
97: do {
98: /* Set up fixed-size output buffer. */
1.17 stevesk 99: outgoing_stream.next_out = buf;
1.2 markus 100: outgoing_stream.avail_out = sizeof(buf);
101:
102: /* Compress as much data into the buffer as possible. */
103: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
104: switch (status) {
105: case Z_OK:
106: /* Append compressed data to output_buffer. */
107: buffer_append(output_buffer, buf,
1.6 markus 108: sizeof(buf) - outgoing_stream.avail_out);
1.2 markus 109: break;
110: default:
1.18 markus 111: deflate_failed = 1;
1.2 markus 112: fatal("buffer_compress: deflate returned %d", status);
113: /* NOTREACHED */
114: }
1.6 markus 115: } while (outgoing_stream.avail_out == 0);
1.1 deraadt 116: }
117:
1.4 markus 118: /*
119: * Uncompresses the contents of input_buffer into output_buffer. All packets
120: * uncompressed using this function will form a single compressed data
121: * stream; however, data will be flushed at the end of every call so that
122: * each output_buffer. This must be called for the same size units that the
123: * buffer_compress was called, and in the same order that buffers compressed
124: * with that. This appends the uncompressed data to the output buffer.
125: */
1.1 deraadt 126:
1.7 markus 127: void
1.2 markus 128: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 129: {
1.17 stevesk 130: u_char buf[4096];
1.2 markus 131: int status;
1.1 deraadt 132:
1.17 stevesk 133: incoming_stream.next_in = buffer_ptr(input_buffer);
1.2 markus 134: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 135:
1.6 markus 136: for (;;) {
137: /* Set up fixed-size output buffer. */
1.17 stevesk 138: incoming_stream.next_out = buf;
1.6 markus 139: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 140:
1.2 markus 141: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
142: switch (status) {
143: case Z_OK:
144: buffer_append(output_buffer, buf,
1.6 markus 145: sizeof(buf) - incoming_stream.avail_out);
1.2 markus 146: break;
147: case Z_BUF_ERROR:
1.4 markus 148: /*
149: * Comments in zlib.h say that we should keep calling
150: * inflate() until we get an error. This appears to
151: * be the error that we get.
152: */
1.2 markus 153: return;
154: default:
1.18 markus 155: inflate_failed = 1;
1.2 markus 156: fatal("buffer_uncompress: inflate returned %d", status);
1.6 markus 157: /* NOTREACHED */
1.2 markus 158: }
1.1 deraadt 159: }
160: }
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