/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* $Id: net.c,v 1.10 2000/06/22 21:58:43 tale Exp $ */

#include <config.h>

#include <errno.h>
#include <unistd.h>

#include <isc/net.h>
#include <isc/once.h>
#include <isc/string.h>
#include <isc/util.h>

#if defined(ISC_PLATFORM_HAVEIPV6) && defined(ISC_PLATFORM_NEEDIN6ADDRANY)
const struct in6_addr isc_net_in6addrany = IN6ADDR_ANY_INIT;
#endif

static isc_once_t 	once = ISC_ONCE_INIT;
static isc_result_t	ipv4_result = ISC_R_NOTFOUND;
static isc_result_t	ipv6_result = ISC_R_NOTFOUND;

static isc_result_t
try_proto(int domain) {
	int s;

	s = socket(domain, SOCK_STREAM, 0);
	if (s == -1) {
		switch (errno) {
#ifdef EAFNOSUPPORT
		case EAFNOSUPPORT:
#endif
#ifdef EPROTONOSUPPORT
		case EPROTONOSUPPORT:
#endif
#ifdef EINVAL
		case EINVAL:
#endif
			return (ISC_R_NOTFOUND);
		default:
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "socket() failed: %s",
					 strerror(errno));
			return (ISC_R_UNEXPECTED);
		}
	}
	close (s);

	return (ISC_R_SUCCESS);
}

static void
initialize_action(void) {
	ipv4_result = try_proto(PF_INET);
#ifdef ISC_PLATFORM_HAVEIPV6
#ifdef ISC_PLATFORM_HAVEIN6PKTINFO
	ipv6_result = try_proto(PF_INET6);
#else
	ipv6_result = 0;
#endif
#endif
}

static void
initialize(void) {
	RUNTIME_CHECK(isc_once_do(&once, initialize_action) == ISC_R_SUCCESS);
}

isc_result_t
isc_net_probeipv4(void) {

	/*
	 * Check if the system's kernel supports IPv4.
	 */

	initialize();
	return (ipv4_result);
}

isc_result_t
isc_net_probeipv6(void) {

	/*
	 * Check if the system's kernel supports IPv6.
	 */

	initialize();
	return (ipv6_result);
}
