openbsd-compat/bindresvport.c

   1 /* This file has be substantially modified from the original OpenBSD source */
   2
   3 /*      $OpenBSD: bindresvport.c,v 1.17 2005/12/21 01:40:22 millert 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 /* OPENBSD ORIGINAL: lib/libc/rpc/bindresvport.c */
  32
  33 #include "includes.h"
  34
  35 #ifndef HAVE_BINDRESVPORT_SA
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38
  39 #include <netinet/in.h>
  40 #include <arpa/inet.h>
  41
  42 #include <errno.h>
  43 #include <string.h>
  44
  45 #define STARTPORT 600
  46 #define ENDPORT (IPPORT_RESERVED - 1)
  47 #define NPORTS  (ENDPORT - STARTPORT + 1)
  48
  49 /*
  50  * Bind a socket to a privileged IP port
  51  */
  52 int
  53 bindresvport_sa(int sd, struct sockaddr *sa)
  54 {
  55         int error, af;
  56         struct sockaddr_storage myaddr;
  57         struct sockaddr_in *in;
  58         struct sockaddr_in6 *in6;
  59         u_int16_t *portp;
  60         u_int16_t port;
  61         socklen_t salen;
  62         int i;
  63
  64         if (sa == NULL) {
  65                 memset(&myaddr, 0, sizeof(myaddr));
  66                 sa = (struct sockaddr *)&myaddr;
  67
  68                 if (getsockname(sd, sa, &salen) == -1)
  69                         return -1;      /* errno is correctly set */
  70
  71                 af = sa->sa_family;
  72                 memset(&myaddr, 0, salen);
  73         } else
  74                 af = sa->sa_family;
  75
  76         if (af == AF_INET) {
  77                 in = (struct sockaddr_in *)sa;
  78                 salen = sizeof(struct sockaddr_in);
  79                 portp = &in->sin_port;
  80         } else if (af == AF_INET6) {
  81                 in6 = (struct sockaddr_in6 *)sa;
  82                 salen = sizeof(struct sockaddr_in6);
  83                 portp = &in6->sin6_port;
  84         } else {
  85                 errno = EPFNOSUPPORT;
  86                 return (-1);
  87         }
  88         sa->sa_family = af;
  89
  90         port = ntohs(*portp);
  91         if (port == 0)
  92                 port = (arc4random() % NPORTS) + STARTPORT;
  93
  94         /* Avoid warning */
  95         error = -1;
  96
  97         for(i = 0; i < NPORTS; i++) {
  98                 *portp = htons(port);
  99
 100                 error = bind(sd, sa, salen);
 101
 102                 /* Terminate on success */
 103                 if (error == 0)
 104                         break;
 105
 106                 /* Terminate on errors, except "address already in use" */
 107                 if ((error < 0) && !((errno == EADDRINUSE) || (errno == EINVAL)))
 108                         break;
 109
 110                 port++;
 111                 if (port > ENDPORT)
 112                         port = STARTPORT;
 113         }
 114
 115         return (error);
 116 }
 117
 118 #endif /* HAVE_BINDRESVPORT_SA */