1 /*
2 * ut_sim.c
3 *
4 * an unreliable transport simulator
5 * (for testing replay databases and suchlike)
6 *
7 * David A. McGrew
8 * Cisco Systems, Inc.
9 */
10
11 /*
12 *
13 * Copyright (c) 2001-2006, Cisco Systems, Inc.
14 * All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 *
20 * Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 *
23 * Redistributions in binary form must reproduce the above
24 * copyright notice, this list of conditions and the following
25 * disclaimer in the documentation and/or other materials provided
26 * with the distribution.
27 *
28 * Neither the name of the Cisco Systems, Inc. nor the names of its
29 * contributors may be used to endorse or promote products derived
30 * from this software without specific prior written permission.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
35 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
36 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43 * OF THE POSSIBILITY OF SUCH DAMAGE.
44 *
45 */
46
47
48 #include "ut_sim.h"
49
50
51 int
ut_compar(const void * a,const void * b)52 ut_compar(const void *a, const void *b) {
53 return rand() > (RAND_MAX/2) ? -1 : 1;
54 }
55
56 void
ut_init(ut_connection * utc)57 ut_init(ut_connection *utc) {
58 int i;
59 utc->index = 0;
60
61 for (i=0; i < UT_BUF; i++)
62 utc->buffer[i] = i;
63
64 qsort(utc->buffer, UT_BUF, sizeof(uint32_t), ut_compar);
65
66 utc->index = UT_BUF - 1;
67 }
68
69 uint32_t
ut_next_index(ut_connection * utc)70 ut_next_index(ut_connection *utc) {
71 uint32_t tmp;
72
73 tmp = utc->buffer[0];
74 utc->index++;
75 utc->buffer[0] = utc->index;
76
77 qsort(utc->buffer, UT_BUF, sizeof(uint32_t), ut_compar);
78
79 return tmp;
80 }
81
82
83
84 #ifdef UT_TEST
85
86 #include <stdio.h>
87
88 int
main()89 main() {
90 uint32_t i, irecvd, idiff;
91 ut_connection utc;
92
93 ut_init(&utc);
94
95 for (i=0; i < 1000; i++) {
96 irecvd = ut_next_index(&utc);
97 idiff = i - irecvd;
98 printf("%lu\t%lu\t%d\n", i, irecvd, idiff);
99 }
100
101 return 0;
102 }
103
104
105 #endif
106