[CIFS] Forgot to add two new files from previous commit

/*

 *  fs/cifs/dns_resolve.c

 *

 *   Copyright (c) 2007 Igor Mammedov

 *   Author(s): Igor Mammedov (niallain@gmail.com)

 *              Steve French (sfrench@us.ibm.com)

 *

 *   Contains the CIFS DFS upcall routines used for hostname to

 *   IP address translation.

 *

 *   This library is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU Lesser General Public License as published

 *   by the Free Software Foundation; either version 2.1 of the License, or

 *   (at your option) any later version.

 *

 *   This library is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See

 *   the GNU Lesser General Public License for more details.

 *

 *   You should have received a copy of the GNU Lesser General Public License

 *   along with this library; if not, write to the Free Software

 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */

#include <keys/user-type.h>

#include "dns_resolve.h"

#include "cifsglob.h"

#include "cifsproto.h"

#include "cifs_debug.h"

static int dns_resolver_instantiate(struct key *key, const void *data,

		size_t datalen)

{

	int rc = 0;

	char *ip;

	ip = kmalloc(datalen+1, GFP_KERNEL);

	if (!ip)

		return -ENOMEM;

	memcpy(ip, data, datalen);

	ip[datalen] = '\0';

	rcu_assign_pointer(key->payload.data, ip);

	return rc;

}

struct key_type key_type_dns_resolver = {

	.name        = "dns_resolver",

	.def_datalen = sizeof(struct in_addr),

	.describe    = user_describe,

	.instantiate = dns_resolver_instantiate,

	.match       = user_match,

};

/* Resolves server name to ip address.

 * input:

 * 	unc - server UNC

 * output:

 * 	*ip_addr - pointer to server ip, caller responcible for freeing it.

 * return 0 on success

 */

int

dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) {

	int rc = -EAGAIN;

	struct key *rkey;

	char *name;

	int len;

	if ((!ip_addr) || (!unc))

		return -EINVAL;

	/* search for server name delimiter */

	len = strlen(unc);

	if (len < 3) {

		cFYI(1, ("%s: unc is too short: %s", __FUNCTION__, unc));

		return -EINVAL;

	}

	len -= 2;

	name = memchr(unc+2, '\\', len);

	if (!name) {

		cFYI(1, ("%s: probably server name is whole unc: %s",

					__FUNCTION__, unc));

	} else {

		len = (name - unc) - 2/* leading // */;

	}

	name = kmalloc(len+1, GFP_KERNEL);

	if (!name) {

		rc = -ENOMEM;

		return rc;

	}

	memcpy(name, unc+2, len);

	name[len] = 0;

	rkey = request_key(&key_type_dns_resolver, name, "");

	if (!IS_ERR(rkey)) {

		len = strlen(rkey->payload.data);

		*ip_addr = kmalloc(len+1, GFP_KERNEL);

		if (*ip_addr) {

			memcpy(*ip_addr, rkey->payload.data, len);

			(*ip_addr)[len] = '\0';

			cFYI(1, ("%s: resolved: %s to %s", __FUNCTION__,

					rkey->description,

					*ip_addr

				));

			rc = 0;

		} else {

			rc = -ENOMEM;

		}

		key_put(rkey);

	} else {

		cERROR(1, ("%s: unable to resolve: %s", __FUNCTION__, name));

	}

	kfree(name);

	return rc;

}

/*

 *   fs/cifs/dns_resolve.h -- DNS Resolver upcall management for CIFS DFS

 *                            Handles host name to IP address resolution

 * 

 *   Copyright (c) International Business Machines  Corp., 2008

 *   Author(s): Steve French (sfrench@us.ibm.com)

 *

 *   This library is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU Lesser General Public License as published

 *   by the Free Software Foundation; either version 2.1 of the License, or

 *   (at your option) any later version.

 *

 *   This library is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See

 *   the GNU Lesser General Public License for more details.

 *

 *   You should have received a copy of the GNU Lesser General Public License

 *   along with this library; if not, write to the Free Software

 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */

#ifndef _DNS_RESOLVE_H

#define _DNS_RESOLVE_H

#ifdef __KERNEL__

#include <linux/key-type.h>

extern struct key_type key_type_dns_resolver;

extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr);

#endif /* KERNEL */

#endif /* _DNS_RESOLVE_H */