/*

 * Portions Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*! \file */

/*

 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.

 * 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.

 * 3. Neither the name of the project nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``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 PROJECT OR CONTRIBUTORS 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.

 */

/*

 * XXX

 * Issues to be discussed:

 * - Return values.  There seems to be no standard for return value (RFC2553)

 *   but INRIA implementation returns EAI_xxx defined for getaddrinfo().

 */

/**

 *    This function is equivalent to the getnameinfo(3) function defined in

 *    RFC2133. lwres_getnameinfo() returns the hostname for the struct

 *    sockaddr sa which is salen bytes long. The hostname is of length

 *    hostlen and is returned via *host. The maximum length of the hostname

 *    is 1025 bytes: #NI_MAXHOST.

 *

 *    The name of the service associated with the port number in sa is

 *    returned in *serv. It is servlen bytes long. The maximum length of the

 *    service name is #NI_MAXSERV - 32 bytes.

 *

 *    The flags argument sets the following bits:

 *

 * \li   #NI_NOFQDN:

 *           A fully qualified domain name is not required for local hosts.

 *           The local part of the fully qualified domain name is returned

 *           instead.

 *

 * \li   #NI_NUMERICHOST

 *           Return the address in numeric form, as if calling inet_ntop(),

 *           instead of a host name.

 *

 * \li   #NI_NAMEREQD

 *           A name is required. If the hostname cannot be found in the DNS

 *           and this flag is set, a non-zero error code is returned. If the

 *           hostname is not found and the flag is not set, the address is

 *           returned in numeric form.

 *

 * \li   #NI_NUMERICSERV

 *           The service name is returned as a digit string representing the

 *           port number.

 *

 * \li   #NI_DGRAM

 *           Specifies that the service being looked up is a datagram

 *           service, and causes getservbyport() to be called with a second

 *           argument of "udp" instead of its default of "tcp". This is

 *           required for the few ports (512-514) that have different

 *           services for UDP and TCP.

 *

 * \section getnameinfo_return Return Values

 *

 *    lwres_getnameinfo() returns 0 on success or a non-zero error code if

 *    an error occurs.

 *

 * \section getname_see See Also

 *

 *    RFC2133, getservbyport(),

 *    lwres_getnamebyaddr(). lwres_net_ntop().

 *

 * \section getnameinfo_bugs Bugs

 *

 *    RFC2133 fails to define what the nonzero return values of

 *    getnameinfo() are.

 */

#include <config.h>

#include <inttypes.h>

#include <stdio.h>

#include <string.h>

#include <lwres/lwres.h>

#include <lwres/net.h>

#include <lwres/netdb.h>

#include "print_p.h"

#include "assert_p.h"

#include "unreachable_p.h"

#define SUCCESS 0

/*% afd structure definition */

static struct afd {

	int a_af;

	size_t a_addrlen;

	size_t a_socklen;

} afdl [] = {

	/*!

	 * First entry is linked last...

	 */

	{ AF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in) },

	{ AF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6) },

	{0, 0, 0},

};

#define ENI_NOSERVNAME	1

#define ENI_NOHOSTNAME	2

#define ENI_MEMORY	3

#define ENI_SYSTEM	4

#define ENI_FAMILY	5

#define ENI_SALEN	6

#define ENI_NOSOCKET 	7

/*!

 * The test against 0 is there to keep the Solaris compiler

 * from complaining about "end-of-loop code not reached".

 */

#define ERR(code) \

	do { result = (code);			\

		if (result != 0) goto cleanup;	\

	} while (0)

/*% lightweight resolver socket address structure to hostname and service name */

int

lwres_getnameinfo(const struct sockaddr *sa, size_t salen, char *host,

		  size_t hostlen, char *serv, size_t servlen, int flags)

{

	struct afd *afd = NULL;

	struct servent *sp;

	unsigned short port;

#ifdef LWRES_PLATFORM_HAVESALEN

	size_t len;

#endif

	int family, i;

	const void *addr;

#if 0

	unsigned long v4a;

	unsigned char pfx;

#endif

	char numserv[sizeof("65000")];

	char numaddr[sizeof("abcd:abcd:abcd:abcd:abcd:abcd:255.255.255.255")

		    + 1 + sizeof("4294967295")];

	const char *proto;

	uint32_t lwf = 0;

	lwres_context_t *lwrctx = NULL;

	lwres_gnbaresponse_t *by = NULL;

	int result = SUCCESS;

	int n;

	if (sa == NULL)

		ERR(ENI_NOSOCKET);

#ifdef LWRES_PLATFORM_HAVESALEN

	len = sa->sa_len;

	if (len != salen)

		ERR(ENI_SALEN);

#endif

	family = sa->sa_family;

	for (i = 0; afdl[i].a_af; i++)

		if (afdl[i].a_af == family) {

			afd = &afdl[i];

			goto found;

		}

	ERR(ENI_FAMILY);

 found:

	if (salen != afd->a_socklen)

		ERR(ENI_SALEN);

	switch (family) {

	case AF_INET:

		port = ((const struct sockaddr_in *)sa)->sin_port;

		addr = &((const struct sockaddr_in *)sa)->sin_addr.s_addr;

		break;

	case AF_INET6:

		port = ((const struct sockaddr_in6 *)sa)->sin6_port;

		addr = ((const struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;

		break;

	default:

		port = 0;

		addr = NULL;

		POST(port); POST(addr);

		INSIST(0);

	}

	proto = (flags & NI_DGRAM) ? "udp" : "tcp";

	if (serv == NULL || servlen == 0U) {

		/*

		 * Caller does not want service.

		 */

	} else if ((flags & NI_NUMERICSERV) != 0 ||

		   (sp = getservbyport(port, proto)) == NULL) {

		snprintf(numserv, sizeof(numserv), "%d", ntohs(port));

		if ((strlen(numserv) + 1) > servlen)

			ERR(ENI_MEMORY);

		strcpy(serv, numserv);

	} else {

		if ((strlen(sp->s_name) + 1) > servlen)

			ERR(ENI_MEMORY);

		strcpy(serv, sp->s_name);

	}

#if 0

	switch (sa->sa_family) {

	case AF_INET:

		v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr;

		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))

			flags |= NI_NUMERICHOST;

		v4a >>= IN_CLASSA_NSHIFT;

		if (v4a == 0 || v4a == IN_LOOPBACKNET)

			flags |= NI_NUMERICHOST;

		break;

	case AF_INET6:

		pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0];

		if (pfx == 0 || pfx == 0xfe || pfx == 0xff)

			flags |= NI_NUMERICHOST;

		break;

	}

#endif

	if (host == NULL || hostlen == 0U) {

		/*

		 * What should we do?

		 */

	} else if (flags & NI_NUMERICHOST) {

		if (lwres_net_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))

		    == NULL)

			ERR(ENI_SYSTEM);

#if defined(LWRES_HAVE_SIN6_SCOPE_ID)

		if (afd->a_af == AF_INET6 &&

		    ((const struct sockaddr_in6 *)sa)->sin6_scope_id) {

			char *p = numaddr + strlen(numaddr);

			const char *stringscope = NULL;

#if 0

			if ((flags & NI_NUMERICSCOPE) == 0) {

				/*

				 * Vendors may want to add support for

				 * non-numeric scope identifier.

				 */

				stringscope = foo;

			}

#endif

			if (stringscope == NULL) {

				snprintf(p, sizeof(numaddr) - (p - numaddr),

				    "%%%u",

				    ((const struct sockaddr_in6 *)sa)->sin6_scope_id);

			} else {

				snprintf(p, sizeof(numaddr) - (p - numaddr),

				    "%%%s", stringscope);

			}

		}

#endif

		if (strlen(numaddr) + 1 > hostlen)

			ERR(ENI_MEMORY);

		strcpy(host, numaddr);

	} else {

		switch (family) {

		case AF_INET:

			lwf = LWRES_ADDRTYPE_V4;

			break;

		case AF_INET6:

			lwf = LWRES_ADDRTYPE_V6;

			break;

		default:

			INSIST(0);

			ISC_UNREACHABLE();

		}

		n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);

		if (n == 0) {

			(void) lwres_conf_parse(lwrctx, lwres_resolv_conf);

			n = lwres_getnamebyaddr(lwrctx, lwf,

						(uint16_t)afd->a_addrlen,

						addr, &by;;

		}

		if (n == 0) {

			if (flags & NI_NOFQDN) {

				char *p = strchr(by->realname, '.');

				if (p)

					*p = '\0';

			}

			if ((strlen(by->realname) + 1) > hostlen)

				ERR(ENI_MEMORY);

			strcpy(host, by->realname);

		} else {

			if (flags & NI_NAMEREQD)

				ERR(ENI_NOHOSTNAME);

			if (lwres_net_ntop(afd->a_af, addr, numaddr,

					   sizeof(numaddr))

			    == NULL)

				ERR(ENI_NOHOSTNAME);

			if ((strlen(numaddr) + 1) > hostlen)

				ERR(ENI_MEMORY);

			strcpy(host, numaddr);

		}

	}

	result = SUCCESS;

 cleanup:

	if (by != NULL)

		lwres_gnbaresponse_free(lwrctx, &by;;

	if (lwrctx != NULL) {

		lwres_conf_clear(lwrctx);

		lwres_context_destroy(&lwrctx);

	}

	return (result);

}