1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28#include <errno.h>
29#include <sys/types.h>
30#include <sys/socket.h>
31#include <netinet/in.h>
32#include <string.h>
33#include <unistd.h>
34
35#define START_PORT	600
36#define END_PORT	IPPORT_RESERVED
37#define NUM_PORTS	(END_PORT - START_PORT)
38
39int bindresvport(int sd, struct sockaddr_in *sin)
40{
41    static short        port;
42    struct sockaddr_in  sin0;
43    int                 nn, ret;
44
45    if (sin == NULL) {
46        sin = &sin0;
47        memset( sin, 0, sizeof *sin );
48        sin->sin_family = AF_INET;
49    } else if (sin->sin_family != AF_INET) {
50        errno = EPFNOSUPPORT;
51        return -1;
52    }
53
54    if (port == 0) {
55        port = START_PORT + (getpid() % NUM_PORTS);
56    }
57
58    for (nn = NUM_PORTS; nn > 0; nn--, port++)
59    {
60        if (port == END_PORT)
61            port = START_PORT;
62
63        sin->sin_port = htons(port);
64        do {
65            ret = bind(sd, (struct sockaddr*)sin, sizeof(*sin));
66        } while (ret < 0 && errno == EINTR);
67
68        if (!ret)
69            break;
70    }
71    return ret;
72}
73