text: /* This file has be substantially modified from the original OpenBSD source */
  
  /*	$OpenBSD: bindresvport.c,v 1.17 2005/12/21 01:40:22 millert Exp $	*/
  
  /*
   * Copyright 1996, Jason Downs.  All rights reserved.
   * Copyright 1998, Theo de Raadt.  All rights reserved.
   * Copyright 2000, Damien Miller.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  /* OPENBSD ORIGINAL: lib/libc/rpc/bindresvport.c */
  
  #include "includes.h"
  
  #ifndef HAVE_BINDRESVPORT_SA
  #include <sys/types.h>
  #include <sys/socket.h>
  
  #include <netinet/in.h>
  #include <arpa/inet.h>
  
  #include <errno.h>
  #include <string.h>
  
  #define STARTPORT 600
  #define ENDPORT (IPPORT_RESERVED - 1)
  #define NPORTS	(ENDPORT - STARTPORT + 1)
  
  /*
   * Bind a socket to a privileged IP port
   */
  int
  bindresvport_sa(int sd, struct sockaddr *sa)
  {
  	int error, af;
  	struct sockaddr_storage myaddr;
  	struct sockaddr_in *in;
  	struct sockaddr_in6 *in6;
  	u_int16_t *portp;
  	u_int16_t port;
  	socklen_t salen = sizeof(struct sockaddr_storage);
  	int i;
  
  	if (sa == NULL) {
  		memset(&myaddr, 0, sizeof(myaddr));
  		sa = (struct sockaddr *)&myaddr;
  		salen = sizeof(myaddr);
  
  		if (getsockname(sd, sa, &salen) == -1)
  			return -1;	/* errno is correctly set */
  
  		af = sa->sa_family;
  		memset(&myaddr, 0, salen);
  	} else
  		af = sa->sa_family;
  
  	if (af == AF_INET) {
  		in = (struct sockaddr_in *)sa;
  		salen = sizeof(struct sockaddr_in);
  		portp = &in->sin_port;
  	} else if (af == AF_INET6) {
  		in6 = (struct sockaddr_in6 *)sa;
  		salen = sizeof(struct sockaddr_in6);
  		portp = &in6->sin6_port;
  	} else {
  		errno = EPFNOSUPPORT;
  		return (-1);
  	}
  	sa->sa_family = af;
  
  	port = ntohs(*portp);
  	if (port == 0)
  		port = arc4random_uniform(NPORTS) + STARTPORT;
  
  	/* Avoid warning */
  	error = -1;
  
  	for(i = 0; i < NPORTS; i++) {
  		*portp = htons(port);
  		
  		error = bind(sd, sa, salen);
  
  		/* Terminate on success */
  		if (error == 0)
  			break;
  			
  		/* Terminate on errors, except "address already in use" */
  		if ((error < 0) && !((errno == EADDRINUSE) || (errno == EINVAL)))
  			break;
  			
  		port++;
  		if (port > ENDPORT)
  			port = STARTPORT;
  	}
  
  	return (error);
  }
  
  #endif /* HAVE_BINDRESVPORT_SA */
  