usr/src/lib/libbc/libc/net/bindresvport.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1987 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include <sys/types.h>
  30 #include <errno.h>
  31 #include <sys/socket.h>
  32 #include <netinet/in.h>
  33
  34 /*
  35  * Bind a socket to a privileged IP port
  36  */
  37 int
  38 bindresvport(int sd, struct sockaddr_in *sin)
  39 {
  40         int res;
  41         static short port;
  42         struct sockaddr_in myaddr;
  43         int i;
  44
  45 #define STARTPORT 600
  46 #define ENDPORT (IPPORT_RESERVED - 1)
  47 #define NPORTS  (ENDPORT - STARTPORT + 1)
  48
  49         if (sin == (struct sockaddr_in *)0) {
  50                 sin = &myaddr;
  51                 bzero(sin, sizeof (*sin));
  52                 sin->sin_family = AF_INET;
  53         } else if (sin->sin_family != AF_INET) {
  54                 errno = EPFNOSUPPORT;
  55                 return (-1);
  56         }
  57         if (port == 0) {
  58                 port = (getpid() % NPORTS) + STARTPORT;
  59         }
  60         res = -1;
  61         errno = EADDRINUSE;
  62         for (i = 0; i < NPORTS && res < 0 && errno == EADDRINUSE; i++) {
  63                 sin->sin_port = htons(port++);
  64                 if (port > ENDPORT) {
  65                         port = STARTPORT;
  66                 }
  67                 res = bind(sd, sin, sizeof(struct sockaddr_in));
  68         }
  69         return (res);
  70 }