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      1 /*	$NetBSD: bindresvport.c,v 1.25 2013/03/11 20:19:28 tron Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2010, Oracle America, Inc.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions are
      8  * met:
      9  *
     10  *     * Redistributions of source code must retain the above copyright
     11  *       notice, this list of conditions and the following disclaimer.
     12  *     * Redistributions in binary form must reproduce the above
     13  *       copyright notice, this list of conditions and the following
     14  *       disclaimer in the documentation and/or other materials
     15  *       provided with the distribution.
     16  *     * Neither the name of the "Oracle America, Inc." nor the names of its
     17  *       contributors may be used to endorse or promote products derived
     18  *       from this software without specific prior written permission.
     19  *
     20  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     21  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     22  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     23  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     24  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
     25  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
     27  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     28  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     29  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     30  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 #if defined(LIBC_SCCS) && !defined(lint)
     36 #if 0
     37 static char *sccsid = "@(#)bindresvport.c 1.8 88/02/08 SMI";
     38 static char *sccsid = "@(#)bindresvport.c	2.2 88/07/29 4.0 RPCSRC";
     39 #else
     40 __RCSID("$NetBSD: bindresvport.c,v 1.25 2013/03/11 20:19:28 tron Exp $");
     41 #endif
     42 #endif
     43 
     44 /*
     45  * Copyright (c) 1987 by Sun Microsystems, Inc.
     46  */
     47 
     48 #include "namespace.h"
     49 
     50 #include <sys/types.h>
     51 #include <sys/socket.h>
     52 
     53 #include <netinet/in.h>
     54 
     55 #include <errno.h>
     56 #include <string.h>
     57 #include <unistd.h>
     58 
     59 #include <rpc/rpc.h>
     60 #include "svc_fdset.h"
     61 
     62 #ifdef __weak_alias
     63 __weak_alias(bindresvport,_bindresvport)
     64 __weak_alias(bindresvport_sa,_bindresvport_sa)
     65 #endif
     66 
     67 /*
     68  * Bind a socket to a privileged IP port
     69  */
     70 int
     71 bindresvport(int sd, struct sockaddr_in *brsin)
     72 {
     73 	return bindresvport_sa(sd, (struct sockaddr *)(void *)brsin);
     74 }
     75 
     76 /*
     77  * Bind a socket to a privileged IP port
     78  */
     79 int
     80 bindresvport_sa(int sd, struct sockaddr *sa)
     81 {
     82 	int error, old;
     83 	struct sockaddr_storage myaddr;
     84 	struct sockaddr_in *brsin;
     85 #ifdef INET6
     86 	struct sockaddr_in6 *brsin6;
     87 #endif
     88 	int proto, portrange, portlow;
     89 	u_int16_t *portp;
     90 	socklen_t salen;
     91 	int af;
     92 
     93 	if (sa == NULL) {
     94 		salen = sizeof(myaddr);
     95 		sa = (struct sockaddr *)(void *)&myaddr;
     96 
     97 		if (getsockname(sd, sa, &salen) == -1)
     98 			return -1;	/* errno is correctly set */
     99 
    100 		af = sa->sa_family;
    101 		memset(sa, 0, salen);
    102 	} else
    103 		af = sa->sa_family;
    104 
    105 	switch (af) {
    106 	case AF_INET:
    107 		proto = IPPROTO_IP;
    108 		portrange = IP_PORTRANGE;
    109 		portlow = IP_PORTRANGE_LOW;
    110 		brsin = (struct sockaddr_in *)(void *)sa;
    111 		salen = sizeof(struct sockaddr_in);
    112 		portp = &brsin->sin_port;
    113 		break;
    114 #ifdef INET6
    115 	case AF_INET6:
    116 		proto = IPPROTO_IPV6;
    117 		portrange = IPV6_PORTRANGE;
    118 		portlow = IPV6_PORTRANGE_LOW;
    119 		brsin6 = (struct sockaddr_in6 *)(void *)sa;
    120 		salen = sizeof(struct sockaddr_in6);
    121 		portp = &brsin6->sin6_port;
    122 		break;
    123 #endif
    124 	default:
    125 		errno = EPFNOSUPPORT;
    126 		return (-1);
    127 	}
    128 	sa->sa_family = af;
    129 	sa->sa_len = salen;
    130 
    131 	if (*portp == 0) {
    132 		socklen_t oldlen = sizeof(old);
    133 
    134 		error = getsockopt(sd, proto, portrange, &old, &oldlen);
    135 		if (error < 0)
    136 			return (error);
    137 		error = setsockopt(sd, proto, portrange, &portlow,
    138 		    (socklen_t)sizeof(portlow));
    139 		if (error < 0)
    140 			return (error);
    141 	}
    142 
    143 	error = bind(sd, sa, salen);
    144 
    145 	if (*portp == 0) {
    146 		int saved_errno = errno;
    147 
    148 		if (error < 0) {
    149 			if (setsockopt(sd, proto, portrange, &old,
    150 			    (socklen_t)sizeof(old)) < 0)
    151 				errno = saved_errno;
    152 			return (error);
    153 		}
    154 
    155 		if (sa != (struct sockaddr *)(void *)&myaddr) {
    156 			/* What did the kernel assign? */
    157 			if (getsockname(sd, sa, &salen) < 0)
    158 				errno = saved_errno;
    159 			return (error);
    160 		}
    161 	}
    162 	return (error);
    163 }
    164