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      1 /*	$NetBSD: sockpair.c,v 1.4 2025/09/05 21:16:23 christos Exp $	*/
      2 
      3 /* $OpenLDAP$ */
      4 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
      5  *
      6  * Copyright 1998-2024 The OpenLDAP Foundation.
      7  * All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted only as authorized by the OpenLDAP
     11  * Public License.
     12  *
     13  * A copy of this license is available in the file LICENSE in the
     14  * top-level directory of the distribution or, alternatively, at
     15  * <http://www.OpenLDAP.org/license.html>.
     16  */
     17 
     18 #include <sys/cdefs.h>
     19 __RCSID("$NetBSD: sockpair.c,v 1.4 2025/09/05 21:16:23 christos Exp $");
     20 
     21 #include "portable.h"
     22 #include <ac/socket.h>
     23 #include <ac/unistd.h>
     24 
     25 #include <lutil.h>
     26 
     27 /* Return a pair of socket descriptors that are connected to each other.
     28  * The returned descriptors are suitable for use with select(). The two
     29  * descriptors may or may not be identical; the function may return
     30  * the same descriptor number in both slots. It is guaranteed that
     31  * data written on sds[1] will be readable on sds[0]. The returned
     32  * descriptors may be datagram oriented, so data should be written
     33  * in reasonably small pieces and read all at once. On Unix systems
     34  * this function is best implemented using a single pipe() call.
     35  */
     36 
     37 int lutil_pair( ber_socket_t sds[2] )
     38 {
     39 #ifdef USE_PIPE
     40 	return pipe( sds );
     41 #else
     42 	struct sockaddr_in si;
     43 	int rc;
     44 	ber_socklen_t len = sizeof(si);
     45 	ber_socket_t sd;
     46 
     47 	sd = socket( AF_INET, SOCK_DGRAM, 0 );
     48 	if ( sd == AC_SOCKET_INVALID ) {
     49 		return sd;
     50 	}
     51 
     52 	(void) memset( (void*) &si, '\0', len );
     53 	si.sin_family = AF_INET;
     54 	si.sin_port = 0;
     55 	si.sin_addr.s_addr = htonl( INADDR_LOOPBACK );
     56 
     57 	rc = bind( sd, (struct sockaddr *)&si, len );
     58 	if ( rc == AC_SOCKET_ERROR ) {
     59 		tcp_close(sd);
     60 		return rc;
     61 	}
     62 
     63 	rc = getsockname( sd, (struct sockaddr *)&si, &len );
     64 	if ( rc == AC_SOCKET_ERROR ) {
     65 		tcp_close(sd);
     66 		return rc;
     67 	}
     68 
     69 	rc = connect( sd, (struct sockaddr *)&si, len );
     70 	if ( rc == AC_SOCKET_ERROR ) {
     71 		tcp_close(sd);
     72 		return rc;
     73 	}
     74 
     75 	sds[0] = sd;
     76 #if !HAVE_WINSOCK
     77 	sds[1] = dup( sds[0] );
     78 #else
     79 	sds[1] = sds[0];
     80 #endif
     81 	return 0;
     82 #endif
     83 }
     84