Annotation of src/usr.bin/ssh/compress.c, Revision 1.22
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"
15:
1.12 markus 16: #include "log.h"
1.1 deraadt 17: #include "buffer.h"
18: #include "zlib.h"
1.13 itojun 19: #include "compress.h"
1.1 deraadt 20:
1.19 provos 21: z_stream incoming_stream;
22: z_stream outgoing_stream;
1.14 markus 23: static int compress_init_send_called = 0;
24: static int compress_init_recv_called = 0;
1.18 markus 25: static int inflate_failed = 0;
26: static int deflate_failed = 0;
1.1 deraadt 27:
1.4 markus 28: /*
29: * Initializes compression; level is compression level from 1 to 9
30: * (as in gzip).
31: */
1.1 deraadt 32:
1.7 markus 33: void
1.14 markus 34: buffer_compress_init_send(int level)
1.1 deraadt 35: {
1.14 markus 36: if (compress_init_send_called == 1)
1.15 markus 37: deflateEnd(&outgoing_stream);
1.14 markus 38: compress_init_send_called = 1;
1.2 markus 39: debug("Enabling compression at level %d.", level);
40: if (level < 1 || level > 9)
41: fatal("Bad compression level %d.", level);
1.14 markus 42: deflateInit(&outgoing_stream, level);
43: }
44: void
45: buffer_compress_init_recv(void)
46: {
47: if (compress_init_recv_called == 1)
48: inflateEnd(&incoming_stream);
49: compress_init_recv_called = 1;
1.2 markus 50: inflateInit(&incoming_stream);
1.1 deraadt 51: }
52:
53: /* Frees any data structures allocated for compression. */
54:
1.7 markus 55: void
1.11 markus 56: buffer_compress_uninit(void)
1.1 deraadt 57: {
1.20 markus 58: debug("compress outgoing: raw data %llu, compressed %llu, factor %.2f",
1.21 markus 59: (unsigned long long)outgoing_stream.total_in,
60: (unsigned long long)outgoing_stream.total_out,
1.16 deraadt 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",
1.21 markus 64: (unsigned long long)incoming_stream.total_out,
65: (unsigned long long)incoming_stream.total_in,
1.16 deraadt 66: incoming_stream.total_out == 0 ? 0.0 :
67: (double) incoming_stream.total_in / incoming_stream.total_out);
1.18 markus 68: if (compress_init_recv_called == 1 && inflate_failed == 0)
1.14 markus 69: inflateEnd(&incoming_stream);
1.18 markus 70: if (compress_init_send_called == 1 && deflate_failed == 0)
1.14 markus 71: deflateEnd(&outgoing_stream);
1.1 deraadt 72: }
73:
1.4 markus 74: /*
75: * Compresses the contents of input_buffer into output_buffer. All packets
76: * compressed using this function will form a single compressed data stream;
77: * however, data will be flushed at the end of every call so that each
78: * output_buffer can be decompressed independently (but in the appropriate
79: * order since they together form a single compression stream) by the
80: * receiver. This appends the compressed data to the output buffer.
81: */
1.1 deraadt 82:
1.7 markus 83: void
1.2 markus 84: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 85: {
1.17 stevesk 86: u_char buf[4096];
1.2 markus 87: int status;
1.1 deraadt 88:
1.2 markus 89: /* This case is not handled below. */
90: if (buffer_len(input_buffer) == 0)
91: return;
92:
93: /* Input is the contents of the input buffer. */
1.17 stevesk 94: outgoing_stream.next_in = buffer_ptr(input_buffer);
1.2 markus 95: outgoing_stream.avail_in = buffer_len(input_buffer);
96:
97: /* Loop compressing until deflate() returns with avail_out != 0. */
98: do {
99: /* Set up fixed-size output buffer. */
1.17 stevesk 100: outgoing_stream.next_out = buf;
1.2 markus 101: outgoing_stream.avail_out = sizeof(buf);
102:
103: /* Compress as much data into the buffer as possible. */
104: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
105: switch (status) {
106: case Z_OK:
107: /* Append compressed data to output_buffer. */
108: buffer_append(output_buffer, buf,
1.6 markus 109: sizeof(buf) - outgoing_stream.avail_out);
1.2 markus 110: break;
111: default:
1.18 markus 112: deflate_failed = 1;
1.2 markus 113: fatal("buffer_compress: deflate returned %d", status);
114: /* NOTREACHED */
115: }
1.6 markus 116: } while (outgoing_stream.avail_out == 0);
1.1 deraadt 117: }
118:
1.4 markus 119: /*
120: * Uncompresses the contents of input_buffer into output_buffer. All packets
121: * uncompressed using this function will form a single compressed data
122: * stream; however, data will be flushed at the end of every call so that
123: * each output_buffer. This must be called for the same size units that the
124: * buffer_compress was called, and in the same order that buffers compressed
125: * with that. This appends the uncompressed data to the output buffer.
126: */
1.1 deraadt 127:
1.7 markus 128: void
1.2 markus 129: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 130: {
1.17 stevesk 131: u_char buf[4096];
1.2 markus 132: int status;
1.1 deraadt 133:
1.17 stevesk 134: incoming_stream.next_in = buffer_ptr(input_buffer);
1.2 markus 135: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 136:
1.6 markus 137: for (;;) {
138: /* Set up fixed-size output buffer. */
1.17 stevesk 139: incoming_stream.next_out = buf;
1.6 markus 140: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 141:
1.2 markus 142: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
143: switch (status) {
144: case Z_OK:
145: buffer_append(output_buffer, buf,
1.6 markus 146: sizeof(buf) - incoming_stream.avail_out);
1.2 markus 147: break;
148: case Z_BUF_ERROR:
1.4 markus 149: /*
150: * Comments in zlib.h say that we should keep calling
151: * inflate() until we get an error. This appears to
152: * be the error that we get.
153: */
1.2 markus 154: return;
155: default:
1.18 markus 156: inflate_failed = 1;
1.2 markus 157: fatal("buffer_uncompress: inflate returned %d", status);
1.6 markus 158: /* NOTREACHED */
1.2 markus 159: }
1.1 deraadt 160: }
161: }
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