openbsd-compat/bindresvport.c

   1 /* This file has be substantially modified from the original OpenBSD source */
   2
   3 /*      $OpenBSD: bindresvport.c,v 1.15 2003/05/20 22:42:35 deraadt Exp $       */
   4
   5 /*
   6  * Copyright 1996, Jason Downs.  All rights reserved.
   7  * Copyright 1998, Theo de Raadt.  All rights reserved.
   8  * Copyright 2000, Damien Miller.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include "includes.h"
  32
  33 #ifndef HAVE_BINDRESVPORT_SA
  34
  35 #include "includes.h"
  36
  37 #define STARTPORT 600
  38 #define ENDPORT (IPPORT_RESERVED - 1)
  39 #define NPORTS  (ENDPORT - STARTPORT + 1)
  40
  41 /*
  42  * Bind a socket to a privileged IP port
  43  */
  44 int
  45 bindresvport_sa(sd, sa)
  46         int sd;
  47         struct sockaddr *sa;
  48 {
  49         int error, af;
  50         struct sockaddr_storage myaddr;
  51         struct sockaddr_in *sin;
  52         struct sockaddr_in6 *sin6;
  53         u_int16_t *portp;
  54         u_int16_t port;
  55         socklen_t salen;
  56         int i;
  57
  58         if (sa == NULL) {
  59                 memset(&myaddr, 0, sizeof(myaddr));
  60                 sa = (struct sockaddr *)&myaddr;
  61
  62                 if (getsockname(sd, sa, &salen) == -1)
  63                         return -1;      /* errno is correctly set */
  64
  65                 af = sa->sa_family;
  66                 memset(&myaddr, 0, salen);
  67         } else
  68                 af = sa->sa_family;
  69
  70         if (af == AF_INET) {
  71                 sin = (struct sockaddr_in *)sa;
  72                 salen = sizeof(struct sockaddr_in);
  73                 portp = &sin->sin_port;
  74         } else if (af == AF_INET6) {
  75                 sin6 = (struct sockaddr_in6 *)sa;
  76                 salen = sizeof(struct sockaddr_in6);
  77                 portp = &sin6->sin6_port;
  78         } else {
  79                 errno = EPFNOSUPPORT;
  80                 return (-1);
  81         }
  82         sa->sa_family = af;
  83
  84         port = ntohs(*portp);
  85         if (port == 0)
  86                 port = (arc4random() % NPORTS) + STARTPORT;
  87
  88         /* Avoid warning */
  89         error = -1;
  90
  91         for(i = 0; i < NPORTS; i++) {
  92                 *portp = htons(port);
  93
  94                 error = bind(sd, sa, salen);
  95
  96                 /* Terminate on success */
  97                 if (error == 0)
  98                         break;
  99
 100                 /* Terminate on errors, except "address already in use" */
 101                 if ((error < 0) && !((errno == EADDRINUSE) || (errno == EINVAL)))
 102                         break;
 103
 104                 port++;
 105                 if (port > ENDPORT)
 106                         port = STARTPORT;
 107         }
 108
 109         return (error);
 110 }
 111
 112 #endif /* HAVE_BINDRESVPORT_SA */