[linux.git] / fs / nfs / dns_resolve.c

/*
 * linux/fs/nfs/dns_resolve.c
 *
 * Copyright (c) 2009 Trond Myklebust <[email protected]>
 *
 * Resolves DNS hostnames into valid ip addresses
 */

#ifdef CONFIG_NFS_USE_KERNEL_DNS

#include <linux/module.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/dns_resolver.h>
#include "dns_resolve.h"

ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
		struct sockaddr *sa, size_t salen)
{
	ssize_t ret;
	char *ip_addr = NULL;
	int ip_len;

	ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);
	if (ip_len > 0)
		ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
	else
		ret = -ESRCH;
	kfree(ip_addr);
	return ret;
}

#else

#include <linux/module.h>
#include <linux/hash.h>
#include <linux/string.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/seq_file.h>
#include <linux/inet.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/cache.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/nfs_fs.h>

#include "nfs4_fs.h"
#include "dns_resolve.h"
#include "cache_lib.h"
#include "netns.h"

#define NFS_DNS_HASHBITS 4
#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)

struct nfs_dns_ent {
	struct cache_head h;

	char *hostname;
	size_t namelen;

	struct sockaddr_storage addr;
	size_t addrlen;
};


static void nfs_dns_ent_update(struct cache_head *cnew,
		struct cache_head *ckey)
{
	struct nfs_dns_ent *new;
	struct nfs_dns_ent *key;

	new = container_of(cnew, struct nfs_dns_ent, h);
	key = container_of(ckey, struct nfs_dns_ent, h);

	memcpy(&new->addr, &key->addr, key->addrlen);
	new->addrlen = key->addrlen;
}

static void nfs_dns_ent_init(struct cache_head *cnew,
		struct cache_head *ckey)
{
	struct nfs_dns_ent *new;
	struct nfs_dns_ent *key;

	new = container_of(cnew, struct nfs_dns_ent, h);
	key = container_of(ckey, struct nfs_dns_ent, h);

	kfree(new->hostname);
	new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
	if (new->hostname) {
		new->namelen = key->namelen;
		nfs_dns_ent_update(cnew, ckey);
	} else {
		new->namelen = 0;
		new->addrlen = 0;
	}
}

static void nfs_dns_ent_put(struct kref *ref)
{
	struct nfs_dns_ent *item;

	item = container_of(ref, struct nfs_dns_ent, h.ref);
	kfree(item->hostname);
	kfree(item);
}

static struct cache_head *nfs_dns_ent_alloc(void)
{
	struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);

	if (item != NULL) {
		item->hostname = NULL;
		item->namelen = 0;
		item->addrlen = 0;
		return &item->h;
	}
	return NULL;
};

static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
{
	return hash_str(key->hostname, NFS_DNS_HASHBITS);
}

static void nfs_dns_request(struct cache_detail *cd,
		struct cache_head *ch,
		char **bpp, int *blen)
{
	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);

	qword_add(bpp, blen, key->hostname);
	(*bpp)[-1] = '\n';
}

static int nfs_dns_upcall(struct cache_detail *cd,
		struct cache_head *ch)
{
	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	int ret;

	ret = nfs_cache_upcall(cd, key->hostname);
	if (ret)
		ret = sunrpc_cache_pipe_upcall(cd, ch);
	return ret;
}

static int nfs_dns_match(struct cache_head *ca,
		struct cache_head *cb)
{
	struct nfs_dns_ent *a;
	struct nfs_dns_ent *b;

	a = container_of(ca, struct nfs_dns_ent, h);
	b = container_of(cb, struct nfs_dns_ent, h);

	if (a->namelen == 0 || a->namelen != b->namelen)
		return 0;
	return memcmp(a->hostname, b->hostname, a->namelen) == 0;
}

static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
		struct cache_head *h)
{
	struct nfs_dns_ent *item;
	long ttl;

	if (h == NULL) {
		seq_puts(m, "# ip address      hostname        ttl\n");
		return 0;
	}
	item = container_of(h, struct nfs_dns_ent, h);
	ttl = item->h.expiry_time - seconds_since_boot();
	if (ttl < 0)
		ttl = 0;

	if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
		char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];

		rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
		seq_printf(m, "%15s ", buf);
	} else
		seq_puts(m, "<none>          ");
	seq_printf(m, "%15s %ld\n", item->hostname, ttl);
	return 0;
}

static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
		struct nfs_dns_ent *key)
{
	struct cache_head *ch;

	ch = sunrpc_cache_lookup(cd,
			&key->h,
			nfs_dns_hash(key));
	if (!ch)
		return NULL;
	return container_of(ch, struct nfs_dns_ent, h);
}

static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
		struct nfs_dns_ent *new,
		struct nfs_dns_ent *key)
{
	struct cache_head *ch;

	ch = sunrpc_cache_update(cd,
			&new->h, &key->h,
			nfs_dns_hash(key));
	if (!ch)
		return NULL;
	return container_of(ch, struct nfs_dns_ent, h);
}

static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
{
	char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
	struct nfs_dns_ent key, *item;
	unsigned int ttl;
	ssize_t len;
	int ret = -EINVAL;

	if (buf[buflen-1] != '\n')
		goto out;
	buf[buflen-1] = '\0';

	len = qword_get(&buf, buf1, sizeof(buf1));
	if (len <= 0)
		goto out;
	key.addrlen = rpc_pton(cd->net, buf1, len,
			(struct sockaddr *)&key.addr,
			sizeof(key.addr));

	len = qword_get(&buf, buf1, sizeof(buf1));
	if (len <= 0)
		goto out;

	key.hostname = buf1;
	key.namelen = len;
	memset(&key.h, 0, sizeof(key.h));

	if (get_uint(&buf, &ttl) < 0)
		goto out;
	if (ttl == 0)
		goto out;
	key.h.expiry_time = ttl + seconds_since_boot();

	ret = -ENOMEM;
	item = nfs_dns_lookup(cd, &key);
	if (item == NULL)
		goto out;

	if (key.addrlen == 0)
		set_bit(CACHE_NEGATIVE, &key.h.flags);

	item = nfs_dns_update(cd, &key, item);
	if (item == NULL)
		goto out;

	ret = 0;
	cache_put(&item->h, cd);
out:
	return ret;
}

static int do_cache_lookup(struct cache_detail *cd,
		struct nfs_dns_ent *key,
		struct nfs_dns_ent **item,
		struct nfs_cache_defer_req *dreq)
{
	int ret = -ENOMEM;

	*item = nfs_dns_lookup(cd, key);
	if (*item) {
		ret = cache_check(cd, &(*item)->h, &dreq->req);
		if (ret)
			*item = NULL;
	}
	return ret;
}

static int do_cache_lookup_nowait(struct cache_detail *cd,
		struct nfs_dns_ent *key,
		struct nfs_dns_ent **item)
{
	int ret = -ENOMEM;

	*item = nfs_dns_lookup(cd, key);
	if (!*item)
		goto out_err;
	ret = -ETIMEDOUT;
	if (!test_bit(CACHE_VALID, &(*item)->h.flags)
			|| (*item)->h.expiry_time < seconds_since_boot()
			|| cd->flush_time > (*item)->h.last_refresh)
		goto out_put;
	ret = -ENOENT;
	if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
		goto out_put;
	return 0;
out_put:
	cache_put(&(*item)->h, cd);
out_err:
	*item = NULL;
	return ret;
}

static int do_cache_lookup_wait(struct cache_detail *cd,
		struct nfs_dns_ent *key,
		struct nfs_dns_ent **item)
{
	struct nfs_cache_defer_req *dreq;
	int ret = -ENOMEM;

	dreq = nfs_cache_defer_req_alloc();
	if (!dreq)
		goto out;
	ret = do_cache_lookup(cd, key, item, dreq);
	if (ret == -EAGAIN) {
		ret = nfs_cache_wait_for_upcall(dreq);
		if (!ret)
			ret = do_cache_lookup_nowait(cd, key, item);
	}
	nfs_cache_defer_req_put(dreq);
out:
	return ret;
}

ssize_t nfs_dns_resolve_name(struct net *net, char *name,
		size_t namelen, struct sockaddr *sa, size_t salen)
{
	struct nfs_dns_ent key = {
		.hostname = name,
		.namelen = namelen,
	};
	struct nfs_dns_ent *item = NULL;
	ssize_t ret;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
	if (ret == 0) {
		if (salen >= item->addrlen) {
			memcpy(sa, &item->addr, item->addrlen);
			ret = item->addrlen;
		} else
			ret = -EOVERFLOW;
		cache_put(&item->h, nn->nfs_dns_resolve);
	} else if (ret == -ENOENT)
		ret = -ESRCH;
	return ret;
}

static struct cache_detail nfs_dns_resolve_template = {
	.owner		= THIS_MODULE,
	.hash_size	= NFS_DNS_HASHTBL_SIZE,
	.name		= "dns_resolve",
	.cache_put	= nfs_dns_ent_put,
	.cache_upcall	= nfs_dns_upcall,
	.cache_request	= nfs_dns_request,
	.cache_parse	= nfs_dns_parse,
	.cache_show	= nfs_dns_show,
	.match		= nfs_dns_match,
	.init		= nfs_dns_ent_init,
	.update		= nfs_dns_ent_update,
	.alloc		= nfs_dns_ent_alloc,
};


int nfs_dns_resolver_cache_init(struct net *net)
{
	int err;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
	if (IS_ERR(nn->nfs_dns_resolve))
		return PTR_ERR(nn->nfs_dns_resolve);

	err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
	if (err)
		goto err_reg;
	return 0;

err_reg:
	cache_destroy_net(nn->nfs_dns_resolve, net);
	return err;
}

void nfs_dns_resolver_cache_destroy(struct net *net)
{
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
	cache_destroy_net(nn->nfs_dns_resolve, net);
}

static int nfs4_dns_net_init(struct net *net)
{
	return nfs_dns_resolver_cache_init(net);
}

static void nfs4_dns_net_exit(struct net *net)
{
	nfs_dns_resolver_cache_destroy(net);
}

static struct pernet_operations nfs4_dns_resolver_ops = {
	.init = nfs4_dns_net_init,
	.exit = nfs4_dns_net_exit,
};

static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
			   void *ptr)
{
	struct super_block *sb = ptr;
	struct net *net = sb->s_fs_info;
	struct nfs_net *nn = net_generic(net, nfs_net_id);
	struct cache_detail *cd = nn->nfs_dns_resolve;
	int ret = 0;

	if (cd == NULL)
		return 0;

	if (!try_module_get(THIS_MODULE))
		return 0;

	switch (event) {
	case RPC_PIPEFS_MOUNT:
		ret = nfs_cache_register_sb(sb, cd);
		break;
	case RPC_PIPEFS_UMOUNT:
		nfs_cache_unregister_sb(sb, cd);
		break;
	default:
		ret = -ENOTSUPP;
		break;
	}
	module_put(THIS_MODULE);
	return ret;
}

static struct notifier_block nfs_dns_resolver_block = {
	.notifier_call	= rpc_pipefs_event,
};

int nfs_dns_resolver_init(void)
{
	int err;

	err = register_pernet_subsys(&nfs4_dns_resolver_ops);
	if (err < 0)
		goto out;
	err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
	if (err < 0)
		goto out1;
	return 0;
out1:
	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
out:
	return err;
}

void nfs_dns_resolver_destroy(void)
{
	rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
}
#endif
Commit	Line	Data
e571cbf1 TM	1	/*
	2	* linux/fs/nfs/dns_resolve.c
	3	*
	4	* Copyright (c) 2009 Trond Myklebust <[email protected]>
	5	*
	6	* Resolves DNS hostnames into valid ip addresses
	7	*/
	8
c2e8139c BS	9	#ifdef CONFIG_NFS_USE_KERNEL_DNS
c2e8139c BS	10
89d77c8f	11	#include <linux/module.h>
c2e8139c	12	#include <linux/sunrpc/clnt.h>
5976687a	13	#include <linux/sunrpc/addr.h>
c2e8139c	14	#include <linux/dns_resolver.h>
17280175	15	#include "dns_resolve.h"
c2e8139c	16
1b340d01	17	ssize_t nfs_dns_resolve_name(struct net net, char name, size_t namelen,
c2e8139c BS	18	struct sockaddr *sa, size_t salen)
	19	{
	20	ssize_t ret;
	21	char *ip_addr = NULL;
	22	int ip_len;
	23
	24	ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);
	25	if (ip_len > 0)
bc224f53	26	ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
c2e8139c BS	27	else
	28	ret = -ESRCH;
	29	kfree(ip_addr);
	30	return ret;
	31	}
	32
	33	#else
	34
89d77c8f	35	#include <linux/module.h>
e571cbf1 TM	36	#include <linux/hash.h>
	37	#include <linux/string.h>
	38	#include <linux/kmod.h>
5a0e3ad6	39	#include <linux/slab.h>
e571cbf1 TM	40	#include <linux/module.h>
	41	#include <linux/socket.h>
	42	#include <linux/seq_file.h>
	43	#include <linux/inet.h>
	44	#include <linux/sunrpc/clnt.h>
5976687a	45	#include <linux/sunrpc/addr.h>
e571cbf1 TM	46	#include <linux/sunrpc/cache.h>
e571cbf1 TM	47	#include <linux/sunrpc/svcauth.h>
9df69c81	48	#include <linux/sunrpc/rpc_pipe_fs.h>
694e096f	49	#include <linux/nfs_fs.h>
e571cbf1	50
694e096f	51	#include "nfs4_fs.h"
e571cbf1 TM	52	#include "dns_resolve.h"
e571cbf1 TM	53	#include "cache_lib.h"
1b340d01	54	#include "netns.h"
e571cbf1 TM	55
	56	#define NFS_DNS_HASHBITS 4
	57	#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
	58
e571cbf1 TM	59	struct nfs_dns_ent {
	60	struct cache_head h;
	61
	62	char *hostname;
	63	size_t namelen;
	64
	65	struct sockaddr_storage addr;
	66	size_t addrlen;
	67	};
	68
	69
ebed9203 TM	70	static void nfs_dns_ent_update(struct cache_head *cnew,
	71	struct cache_head *ckey)
	72	{
	73	struct nfs_dns_ent *new;
	74	struct nfs_dns_ent *key;
	75
	76	new = container_of(cnew, struct nfs_dns_ent, h);
	77	key = container_of(ckey, struct nfs_dns_ent, h);
	78
	79	memcpy(&new->addr, &key->addr, key->addrlen);
	80	new->addrlen = key->addrlen;
	81	}
	82
e571cbf1 TM	83	static void nfs_dns_ent_init(struct cache_head *cnew,
	84	struct cache_head *ckey)
	85	{
	86	struct nfs_dns_ent *new;
	87	struct nfs_dns_ent *key;
	88
	89	new = container_of(cnew, struct nfs_dns_ent, h);
	90	key = container_of(ckey, struct nfs_dns_ent, h);
	91
	92	kfree(new->hostname);
	93	new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
	94	if (new->hostname) {
	95	new->namelen = key->namelen;
ebed9203	96	nfs_dns_ent_update(cnew, ckey);
e571cbf1 TM	97	} else {
	98	new->namelen = 0;
	99	new->addrlen = 0;
	100	}
	101	}
	102
	103	static void nfs_dns_ent_put(struct kref *ref)
	104	{
	105	struct nfs_dns_ent *item;
	106
	107	item = container_of(ref, struct nfs_dns_ent, h.ref);
	108	kfree(item->hostname);
	109	kfree(item);
	110	}
	111
	112	static struct cache_head *nfs_dns_ent_alloc(void)
	113	{
	114	struct nfs_dns_ent item = kmalloc(sizeof(item), GFP_KERNEL);
	115
	116	if (item != NULL) {
	117	item->hostname = NULL;
	118	item->namelen = 0;
	119	item->addrlen = 0;
	120	return &item->h;
	121	}
	122	return NULL;
	123	};
	124
	125	static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
	126	{
	127	return hash_str(key->hostname, NFS_DNS_HASHBITS);
	128	}
	129
	130	static void nfs_dns_request(struct cache_detail *cd,
	131	struct cache_head *ch,
	132	char *bpp, int blen)
	133	{
	134	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	135
	136	qword_add(bpp, blen, key->hostname);
	137	(*bpp)[-1] = '\n';
	138	}
	139
	140	static int nfs_dns_upcall(struct cache_detail *cd,
	141	struct cache_head *ch)
	142	{
	143	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	144	int ret;
	145
	146	ret = nfs_cache_upcall(cd, key->hostname);
	147	if (ret)
21cd1254	148	ret = sunrpc_cache_pipe_upcall(cd, ch);
e571cbf1 TM	149	return ret;
	150	}
	151
	152	static int nfs_dns_match(struct cache_head *ca,
	153	struct cache_head *cb)
	154	{
	155	struct nfs_dns_ent *a;
	156	struct nfs_dns_ent *b;
	157
	158	a = container_of(ca, struct nfs_dns_ent, h);
	159	b = container_of(cb, struct nfs_dns_ent, h);
	160
	161	if (a->namelen == 0 \|\| a->namelen != b->namelen)
	162	return 0;
	163	return memcmp(a->hostname, b->hostname, a->namelen) == 0;
	164	}
	165
	166	static int nfs_dns_show(struct seq_file m, struct cache_detail cd,
	167	struct cache_head *h)
	168	{
	169	struct nfs_dns_ent *item;
	170	long ttl;
	171
	172	if (h == NULL) {
	173	seq_puts(m, "# ip address hostname ttl\n");
	174	return 0;
	175	}
	176	item = container_of(h, struct nfs_dns_ent, h);
c5b29f88	177	ttl = item->h.expiry_time - seconds_since_boot();
e571cbf1 TM	178	if (ttl < 0)
	179	ttl = 0;
	180
	181	if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
	182	char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
	183
	184	rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
	185	seq_printf(m, "%15s ", buf);
	186	} else
	187	seq_puts(m, "<none> ");
	188	seq_printf(m, "%15s %ld\n", item->hostname, ttl);
	189	return 0;
	190	}
	191
0a6566ec	192	static struct nfs_dns_ent nfs_dns_lookup(struct cache_detail cd,
e571cbf1 TM	193	struct nfs_dns_ent *key)
	194	{
	195	struct cache_head *ch;
	196
	197	ch = sunrpc_cache_lookup(cd,
	198	&key->h,
	199	nfs_dns_hash(key));
	200	if (!ch)
	201	return NULL;
	202	return container_of(ch, struct nfs_dns_ent, h);
	203	}
	204
0a6566ec	205	static struct nfs_dns_ent nfs_dns_update(struct cache_detail cd,
e571cbf1 TM	206	struct nfs_dns_ent *new,
	207	struct nfs_dns_ent *key)
	208	{
	209	struct cache_head *ch;
	210
	211	ch = sunrpc_cache_update(cd,
	212	&new->h, &key->h,
	213	nfs_dns_hash(key));
	214	if (!ch)
	215	return NULL;
	216	return container_of(ch, struct nfs_dns_ent, h);
	217	}
	218
	219	static int nfs_dns_parse(struct cache_detail cd, char buf, int buflen)
	220	{
	221	char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
	222	struct nfs_dns_ent key, *item;
8d96b106	223	unsigned int ttl;
e571cbf1 TM	224	ssize_t len;
	225	int ret = -EINVAL;
	226
	227	if (buf[buflen-1] != '\n')
	228	goto out;
	229	buf[buflen-1] = '\0';
	230
	231	len = qword_get(&buf, buf1, sizeof(buf1));
	232	if (len <= 0)
	233	goto out;
599ec129	234	key.addrlen = rpc_pton(cd->net, buf1, len,
e571cbf1 TM	235	(struct sockaddr *)&key.addr,
	236	sizeof(key.addr));
	237
	238	len = qword_get(&buf, buf1, sizeof(buf1));
	239	if (len <= 0)
	240	goto out;
	241
	242	key.hostname = buf1;
	243	key.namelen = len;
	244	memset(&key.h, 0, sizeof(key.h));
	245
8d96b106 N	246	if (get_uint(&buf, &ttl) < 0)
8d96b106 N	247	goto out;
e571cbf1 TM	248	if (ttl == 0)
e571cbf1 TM	249	goto out;
c5b29f88	250	key.h.expiry_time = ttl + seconds_since_boot();
e571cbf1 TM	251
	252	ret = -ENOMEM;
	253	item = nfs_dns_lookup(cd, &key);
	254	if (item == NULL)
	255	goto out;
	256
	257	if (key.addrlen == 0)
	258	set_bit(CACHE_NEGATIVE, &key.h.flags);
	259
	260	item = nfs_dns_update(cd, &key, item);
	261	if (item == NULL)
	262	goto out;
	263
	264	ret = 0;
	265	cache_put(&item->h, cd);
	266	out:
	267	return ret;
	268	}
	269
e571cbf1 TM	270	static int do_cache_lookup(struct cache_detail *cd,
	271	struct nfs_dns_ent *key,
	272	struct nfs_dns_ent **item,
	273	struct nfs_cache_defer_req *dreq)
	274	{
	275	int ret = -ENOMEM;
	276
	277	*item = nfs_dns_lookup(cd, key);
	278	if (*item) {
	279	ret = cache_check(cd, &(*item)->h, &dreq->req);
	280	if (ret)
	281	*item = NULL;
	282	}
	283	return ret;
	284	}
	285
	286	static int do_cache_lookup_nowait(struct cache_detail *cd,
	287	struct nfs_dns_ent *key,
	288	struct nfs_dns_ent **item)
	289	{
	290	int ret = -ENOMEM;
	291
	292	*item = nfs_dns_lookup(cd, key);
	293	if (!*item)
	294	goto out_err;
	295	ret = -ETIMEDOUT;
	296	if (!test_bit(CACHE_VALID, &(*item)->h.flags)
c5b29f88	297	\|\| (*item)->h.expiry_time < seconds_since_boot()
e571cbf1 TM	298	\|\| cd->flush_time > (*item)->h.last_refresh)
	299	goto out_put;
	300	ret = -ENOENT;
	301	if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
	302	goto out_put;
	303	return 0;
	304	out_put:
	305	cache_put(&(*item)->h, cd);
	306	out_err:
	307	*item = NULL;
	308	return ret;
	309	}
	310
	311	static int do_cache_lookup_wait(struct cache_detail *cd,
	312	struct nfs_dns_ent *key,
	313	struct nfs_dns_ent **item)
	314	{
	315	struct nfs_cache_defer_req *dreq;
	316	int ret = -ENOMEM;
	317
	318	dreq = nfs_cache_defer_req_alloc();
	319	if (!dreq)
	320	goto out;
	321	ret = do_cache_lookup(cd, key, item, dreq);
	322	if (ret == -EAGAIN) {
	323	ret = nfs_cache_wait_for_upcall(dreq);
	324	if (!ret)
	325	ret = do_cache_lookup_nowait(cd, key, item);
	326	}
	327	nfs_cache_defer_req_put(dreq);
	328	out:
	329	return ret;
	330	}
	331
1b340d01 SK	332	ssize_t nfs_dns_resolve_name(struct net net, char name,
1b340d01 SK	333	size_t namelen, struct sockaddr *sa, size_t salen)
e571cbf1 TM	334	{
	335	struct nfs_dns_ent key = {
	336	.hostname = name,
	337	.namelen = namelen,
	338	};
	339	struct nfs_dns_ent *item = NULL;
	340	ssize_t ret;
1b340d01	341	struct nfs_net *nn = net_generic(net, nfs_net_id);
e571cbf1	342
1b340d01	343	ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
e571cbf1 TM	344	if (ret == 0) {
	345	if (salen >= item->addrlen) {
	346	memcpy(sa, &item->addr, item->addrlen);
	347	ret = item->addrlen;
	348	} else
	349	ret = -EOVERFLOW;
1b340d01	350	cache_put(&item->h, nn->nfs_dns_resolve);
e571cbf1 TM	351	} else if (ret == -ENOENT)
	352	ret = -ESRCH;
	353	return ret;
	354	}
	355
483479c2 SK	356	static struct cache_detail nfs_dns_resolve_template = {
	357	.owner = THIS_MODULE,
	358	.hash_size = NFS_DNS_HASHTBL_SIZE,
	359	.name = "dns_resolve",
	360	.cache_put = nfs_dns_ent_put,
	361	.cache_upcall = nfs_dns_upcall,
73fb847a	362	.cache_request = nfs_dns_request,
483479c2 SK	363	.cache_parse = nfs_dns_parse,
	364	.cache_show = nfs_dns_show,
	365	.match = nfs_dns_match,
	366	.init = nfs_dns_ent_init,
	367	.update = nfs_dns_ent_update,
	368	.alloc = nfs_dns_ent_alloc,
	369	};
	370
	371
1b340d01	372	int nfs_dns_resolver_cache_init(struct net *net)
e571cbf1	373	{
483479c2	374	int err;
1b340d01	375	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	376
483479c2 SK	377	nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
	378	if (IS_ERR(nn->nfs_dns_resolve))
	379	return PTR_ERR(nn->nfs_dns_resolve);
	380
483479c2	381	err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
1b340d01 SK	382	if (err)
1b340d01 SK	383	goto err_reg;
1b340d01	384	return 0;
9222b955	385
1b340d01	386	err_reg:
483479c2	387	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	388	return err;
	389	}
	390
	391	void nfs_dns_resolver_cache_destroy(struct net *net)
	392	{
	393	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	394
462b8f6b	395	nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
483479c2	396	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	397	}
1b340d01 SK	398
c8d74d9b TM	399	static int nfs4_dns_net_init(struct net *net)
	400	{
	401	return nfs_dns_resolver_cache_init(net);
	402	}
	403
	404	static void nfs4_dns_net_exit(struct net *net)
	405	{
	406	nfs_dns_resolver_cache_destroy(net);
	407	}
	408
	409	static struct pernet_operations nfs4_dns_resolver_ops = {
	410	.init = nfs4_dns_net_init,
	411	.exit = nfs4_dns_net_exit,
	412	};
	413
9df69c81 SK	414	static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
	415	void *ptr)
	416	{
	417	struct super_block *sb = ptr;
	418	struct net *net = sb->s_fs_info;
	419	struct nfs_net *nn = net_generic(net, nfs_net_id);
	420	struct cache_detail *cd = nn->nfs_dns_resolve;
	421	int ret = 0;
	422
	423	if (cd == NULL)
	424	return 0;
	425
	426	if (!try_module_get(THIS_MODULE))
	427	return 0;
	428
	429	switch (event) {
	430	case RPC_PIPEFS_MOUNT:
	431	ret = nfs_cache_register_sb(sb, cd);
	432	break;
	433	case RPC_PIPEFS_UMOUNT:
	434	nfs_cache_unregister_sb(sb, cd);
	435	break;
	436	default:
	437	ret = -ENOTSUPP;
	438	break;
	439	}
	440	module_put(THIS_MODULE);
	441	return ret;
	442	}
	443
	444	static struct notifier_block nfs_dns_resolver_block = {
	445	.notifier_call = rpc_pipefs_event,
	446	};
	447
1b340d01 SK	448	int nfs_dns_resolver_init(void)
1b340d01 SK	449	{
c8d74d9b TM	450	int err;
	451
	452	err = register_pernet_subsys(&nfs4_dns_resolver_ops);
	453	if (err < 0)
	454	goto out;
	455	err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
	456	if (err < 0)
	457	goto out1;
	458	return 0;
	459	out1:
	460	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
	461	out:
	462	return err;
e571cbf1 TM	463	}
	464
	465	void nfs_dns_resolver_destroy(void)
	466	{
9df69c81	467	rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
c8d74d9b	468	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
e571cbf1	469	}
c2e8139c	470	#endif