[mirror_ubuntu-bionic-kernel.git] / fs / nfs / dns_resolve.c

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/nfs/dns_resolve.c
 *
 * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
 *
 * 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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
e571cbf1 TM	2	/*
	3	* linux/fs/nfs/dns_resolve.c
	4	*
	5	* Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
	6	*
	7	* Resolves DNS hostnames into valid ip addresses
	8	*/
	9
c2e8139c BS	10	#ifdef CONFIG_NFS_USE_KERNEL_DNS
c2e8139c BS	11
89d77c8f	12	#include <linux/module.h>
c2e8139c	13	#include <linux/sunrpc/clnt.h>
5976687a	14	#include <linux/sunrpc/addr.h>
c2e8139c	15	#include <linux/dns_resolver.h>
17280175	16	#include "dns_resolve.h"
c2e8139c	17
1b340d01	18	ssize_t nfs_dns_resolve_name(struct net net, char name, size_t namelen,
c2e8139c BS	19	struct sockaddr *sa, size_t salen)
	20	{
	21	ssize_t ret;
	22	char *ip_addr = NULL;
	23	int ip_len;
	24
	25	ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);
	26	if (ip_len > 0)
bc224f53	27	ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
c2e8139c BS	28	else
	29	ret = -ESRCH;
	30	kfree(ip_addr);
	31	return ret;
	32	}
	33
	34	#else
	35
89d77c8f	36	#include <linux/module.h>
e571cbf1 TM	37	#include <linux/hash.h>
	38	#include <linux/string.h>
	39	#include <linux/kmod.h>
5a0e3ad6	40	#include <linux/slab.h>
e571cbf1 TM	41	#include <linux/module.h>
	42	#include <linux/socket.h>
	43	#include <linux/seq_file.h>
	44	#include <linux/inet.h>
	45	#include <linux/sunrpc/clnt.h>
5976687a	46	#include <linux/sunrpc/addr.h>
e571cbf1 TM	47	#include <linux/sunrpc/cache.h>
e571cbf1 TM	48	#include <linux/sunrpc/svcauth.h>
9df69c81	49	#include <linux/sunrpc/rpc_pipe_fs.h>
694e096f	50	#include <linux/nfs_fs.h>
e571cbf1	51
694e096f	52	#include "nfs4_fs.h"
e571cbf1 TM	53	#include "dns_resolve.h"
e571cbf1 TM	54	#include "cache_lib.h"
1b340d01	55	#include "netns.h"
e571cbf1 TM	56
	57	#define NFS_DNS_HASHBITS 4
	58	#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
	59
e571cbf1 TM	60	struct nfs_dns_ent {
	61	struct cache_head h;
	62
	63	char *hostname;
	64	size_t namelen;
	65
	66	struct sockaddr_storage addr;
	67	size_t addrlen;
	68	};
	69
	70
ebed9203 TM	71	static void nfs_dns_ent_update(struct cache_head *cnew,
	72	struct cache_head *ckey)
	73	{
	74	struct nfs_dns_ent *new;
	75	struct nfs_dns_ent *key;
	76
	77	new = container_of(cnew, struct nfs_dns_ent, h);
	78	key = container_of(ckey, struct nfs_dns_ent, h);
	79
	80	memcpy(&new->addr, &key->addr, key->addrlen);
	81	new->addrlen = key->addrlen;
	82	}
	83
e571cbf1 TM	84	static void nfs_dns_ent_init(struct cache_head *cnew,
	85	struct cache_head *ckey)
	86	{
	87	struct nfs_dns_ent *new;
	88	struct nfs_dns_ent *key;
	89
	90	new = container_of(cnew, struct nfs_dns_ent, h);
	91	key = container_of(ckey, struct nfs_dns_ent, h);
	92
	93	kfree(new->hostname);
	94	new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
	95	if (new->hostname) {
	96	new->namelen = key->namelen;
ebed9203	97	nfs_dns_ent_update(cnew, ckey);
e571cbf1 TM	98	} else {
	99	new->namelen = 0;
	100	new->addrlen = 0;
	101	}
	102	}
	103
	104	static void nfs_dns_ent_put(struct kref *ref)
	105	{
	106	struct nfs_dns_ent *item;
	107
	108	item = container_of(ref, struct nfs_dns_ent, h.ref);
	109	kfree(item->hostname);
	110	kfree(item);
	111	}
	112
	113	static struct cache_head *nfs_dns_ent_alloc(void)
	114	{
	115	struct nfs_dns_ent item = kmalloc(sizeof(item), GFP_KERNEL);
	116
	117	if (item != NULL) {
	118	item->hostname = NULL;
	119	item->namelen = 0;
	120	item->addrlen = 0;
	121	return &item->h;
	122	}
	123	return NULL;
	124	};
	125
	126	static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
	127	{
	128	return hash_str(key->hostname, NFS_DNS_HASHBITS);
	129	}
	130
	131	static void nfs_dns_request(struct cache_detail *cd,
	132	struct cache_head *ch,
	133	char *bpp, int blen)
	134	{
	135	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	136
	137	qword_add(bpp, blen, key->hostname);
	138	(*bpp)[-1] = '\n';
	139	}
	140
	141	static int nfs_dns_upcall(struct cache_detail *cd,
	142	struct cache_head *ch)
	143	{
	144	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	145	int ret;
	146
	147	ret = nfs_cache_upcall(cd, key->hostname);
	148	if (ret)
21cd1254	149	ret = sunrpc_cache_pipe_upcall(cd, ch);
e571cbf1 TM	150	return ret;
	151	}
	152
	153	static int nfs_dns_match(struct cache_head *ca,
	154	struct cache_head *cb)
	155	{
	156	struct nfs_dns_ent *a;
	157	struct nfs_dns_ent *b;
	158
	159	a = container_of(ca, struct nfs_dns_ent, h);
	160	b = container_of(cb, struct nfs_dns_ent, h);
	161
	162	if (a->namelen == 0 \|\| a->namelen != b->namelen)
	163	return 0;
	164	return memcmp(a->hostname, b->hostname, a->namelen) == 0;
	165	}
	166
	167	static int nfs_dns_show(struct seq_file m, struct cache_detail cd,
	168	struct cache_head *h)
	169	{
	170	struct nfs_dns_ent *item;
	171	long ttl;
	172
	173	if (h == NULL) {
	174	seq_puts(m, "# ip address hostname ttl\n");
	175	return 0;
	176	}
	177	item = container_of(h, struct nfs_dns_ent, h);
c5b29f88	178	ttl = item->h.expiry_time - seconds_since_boot();
e571cbf1 TM	179	if (ttl < 0)
	180	ttl = 0;
	181
	182	if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
	183	char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
	184
	185	rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
	186	seq_printf(m, "%15s ", buf);
	187	} else
	188	seq_puts(m, "<none> ");
	189	seq_printf(m, "%15s %ld\n", item->hostname, ttl);
	190	return 0;
	191	}
	192
0a6566ec	193	static struct nfs_dns_ent nfs_dns_lookup(struct cache_detail cd,
e571cbf1 TM	194	struct nfs_dns_ent *key)
	195	{
	196	struct cache_head *ch;
	197
	198	ch = sunrpc_cache_lookup(cd,
	199	&key->h,
	200	nfs_dns_hash(key));
	201	if (!ch)
	202	return NULL;
	203	return container_of(ch, struct nfs_dns_ent, h);
	204	}
	205
0a6566ec	206	static struct nfs_dns_ent nfs_dns_update(struct cache_detail cd,
e571cbf1 TM	207	struct nfs_dns_ent *new,
	208	struct nfs_dns_ent *key)
	209	{
	210	struct cache_head *ch;
	211
	212	ch = sunrpc_cache_update(cd,
	213	&new->h, &key->h,
	214	nfs_dns_hash(key));
	215	if (!ch)
	216	return NULL;
	217	return container_of(ch, struct nfs_dns_ent, h);
	218	}
	219
	220	static int nfs_dns_parse(struct cache_detail cd, char buf, int buflen)
	221	{
	222	char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
	223	struct nfs_dns_ent key, *item;
8d96b106	224	unsigned int ttl;
e571cbf1 TM	225	ssize_t len;
	226	int ret = -EINVAL;
	227
	228	if (buf[buflen-1] != '\n')
	229	goto out;
	230	buf[buflen-1] = '\0';
	231
	232	len = qword_get(&buf, buf1, sizeof(buf1));
	233	if (len <= 0)
	234	goto out;
599ec129	235	key.addrlen = rpc_pton(cd->net, buf1, len,
e571cbf1 TM	236	(struct sockaddr *)&key.addr,
	237	sizeof(key.addr));
	238
	239	len = qword_get(&buf, buf1, sizeof(buf1));
	240	if (len <= 0)
	241	goto out;
	242
	243	key.hostname = buf1;
	244	key.namelen = len;
	245	memset(&key.h, 0, sizeof(key.h));
	246
8d96b106 N	247	if (get_uint(&buf, &ttl) < 0)
8d96b106 N	248	goto out;
e571cbf1 TM	249	if (ttl == 0)
e571cbf1 TM	250	goto out;
c5b29f88	251	key.h.expiry_time = ttl + seconds_since_boot();
e571cbf1 TM	252
	253	ret = -ENOMEM;
	254	item = nfs_dns_lookup(cd, &key);
	255	if (item == NULL)
	256	goto out;
	257
	258	if (key.addrlen == 0)
	259	set_bit(CACHE_NEGATIVE, &key.h.flags);
	260
	261	item = nfs_dns_update(cd, &key, item);
	262	if (item == NULL)
	263	goto out;
	264
	265	ret = 0;
	266	cache_put(&item->h, cd);
	267	out:
	268	return ret;
	269	}
	270
e571cbf1 TM	271	static int do_cache_lookup(struct cache_detail *cd,
	272	struct nfs_dns_ent *key,
	273	struct nfs_dns_ent **item,
	274	struct nfs_cache_defer_req *dreq)
	275	{
	276	int ret = -ENOMEM;
	277
	278	*item = nfs_dns_lookup(cd, key);
	279	if (*item) {
	280	ret = cache_check(cd, &(*item)->h, &dreq->req);
	281	if (ret)
	282	*item = NULL;
	283	}
	284	return ret;
	285	}
	286
	287	static int do_cache_lookup_nowait(struct cache_detail *cd,
	288	struct nfs_dns_ent *key,
	289	struct nfs_dns_ent **item)
	290	{
	291	int ret = -ENOMEM;
	292
	293	*item = nfs_dns_lookup(cd, key);
	294	if (!*item)
	295	goto out_err;
	296	ret = -ETIMEDOUT;
	297	if (!test_bit(CACHE_VALID, &(*item)->h.flags)
c5b29f88	298	\|\| (*item)->h.expiry_time < seconds_since_boot()
e571cbf1 TM	299	\|\| cd->flush_time > (*item)->h.last_refresh)
	300	goto out_put;
	301	ret = -ENOENT;
	302	if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
	303	goto out_put;
	304	return 0;
	305	out_put:
	306	cache_put(&(*item)->h, cd);
	307	out_err:
	308	*item = NULL;
	309	return ret;
	310	}
	311
	312	static int do_cache_lookup_wait(struct cache_detail *cd,
	313	struct nfs_dns_ent *key,
	314	struct nfs_dns_ent **item)
	315	{
	316	struct nfs_cache_defer_req *dreq;
	317	int ret = -ENOMEM;
	318
	319	dreq = nfs_cache_defer_req_alloc();
	320	if (!dreq)
	321	goto out;
	322	ret = do_cache_lookup(cd, key, item, dreq);
	323	if (ret == -EAGAIN) {
	324	ret = nfs_cache_wait_for_upcall(dreq);
	325	if (!ret)
	326	ret = do_cache_lookup_nowait(cd, key, item);
	327	}
	328	nfs_cache_defer_req_put(dreq);
	329	out:
	330	return ret;
	331	}
	332
1b340d01 SK	333	ssize_t nfs_dns_resolve_name(struct net net, char name,
1b340d01 SK	334	size_t namelen, struct sockaddr *sa, size_t salen)
e571cbf1 TM	335	{
	336	struct nfs_dns_ent key = {
	337	.hostname = name,
	338	.namelen = namelen,
	339	};
	340	struct nfs_dns_ent *item = NULL;
	341	ssize_t ret;
1b340d01	342	struct nfs_net *nn = net_generic(net, nfs_net_id);
e571cbf1	343
1b340d01	344	ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
e571cbf1 TM	345	if (ret == 0) {
	346	if (salen >= item->addrlen) {
	347	memcpy(sa, &item->addr, item->addrlen);
	348	ret = item->addrlen;
	349	} else
	350	ret = -EOVERFLOW;
1b340d01	351	cache_put(&item->h, nn->nfs_dns_resolve);
e571cbf1 TM	352	} else if (ret == -ENOENT)
	353	ret = -ESRCH;
	354	return ret;
	355	}
	356
483479c2 SK	357	static struct cache_detail nfs_dns_resolve_template = {
	358	.owner = THIS_MODULE,
	359	.hash_size = NFS_DNS_HASHTBL_SIZE,
	360	.name = "dns_resolve",
	361	.cache_put = nfs_dns_ent_put,
	362	.cache_upcall = nfs_dns_upcall,
73fb847a	363	.cache_request = nfs_dns_request,
483479c2 SK	364	.cache_parse = nfs_dns_parse,
	365	.cache_show = nfs_dns_show,
	366	.match = nfs_dns_match,
	367	.init = nfs_dns_ent_init,
	368	.update = nfs_dns_ent_update,
	369	.alloc = nfs_dns_ent_alloc,
	370	};
	371
	372
1b340d01	373	int nfs_dns_resolver_cache_init(struct net *net)
e571cbf1	374	{
483479c2	375	int err;
1b340d01	376	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	377
483479c2 SK	378	nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
	379	if (IS_ERR(nn->nfs_dns_resolve))
	380	return PTR_ERR(nn->nfs_dns_resolve);
	381
483479c2	382	err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
1b340d01 SK	383	if (err)
1b340d01 SK	384	goto err_reg;
1b340d01	385	return 0;
9222b955	386
1b340d01	387	err_reg:
483479c2	388	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	389	return err;
	390	}
	391
	392	void nfs_dns_resolver_cache_destroy(struct net *net)
	393	{
	394	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	395
462b8f6b	396	nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
483479c2	397	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	398	}
1b340d01 SK	399
c8d74d9b TM	400	static int nfs4_dns_net_init(struct net *net)
	401	{
	402	return nfs_dns_resolver_cache_init(net);
	403	}
	404
	405	static void nfs4_dns_net_exit(struct net *net)
	406	{
	407	nfs_dns_resolver_cache_destroy(net);
	408	}
	409
	410	static struct pernet_operations nfs4_dns_resolver_ops = {
	411	.init = nfs4_dns_net_init,
	412	.exit = nfs4_dns_net_exit,
	413	};
	414
9df69c81 SK	415	static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
	416	void *ptr)
	417	{
	418	struct super_block *sb = ptr;
	419	struct net *net = sb->s_fs_info;
	420	struct nfs_net *nn = net_generic(net, nfs_net_id);
	421	struct cache_detail *cd = nn->nfs_dns_resolve;
	422	int ret = 0;
	423
	424	if (cd == NULL)
	425	return 0;
	426
	427	if (!try_module_get(THIS_MODULE))
	428	return 0;
	429
	430	switch (event) {
	431	case RPC_PIPEFS_MOUNT:
	432	ret = nfs_cache_register_sb(sb, cd);
	433	break;
	434	case RPC_PIPEFS_UMOUNT:
	435	nfs_cache_unregister_sb(sb, cd);
	436	break;
	437	default:
	438	ret = -ENOTSUPP;
	439	break;
	440	}
	441	module_put(THIS_MODULE);
	442	return ret;
	443	}
	444
	445	static struct notifier_block nfs_dns_resolver_block = {
	446	.notifier_call = rpc_pipefs_event,
	447	};
	448
1b340d01 SK	449	int nfs_dns_resolver_init(void)
1b340d01 SK	450	{
c8d74d9b TM	451	int err;
	452
	453	err = register_pernet_subsys(&nfs4_dns_resolver_ops);
	454	if (err < 0)
	455	goto out;
	456	err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
	457	if (err < 0)
	458	goto out1;
	459	return 0;
	460	out1:
	461	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
	462	out:
	463	return err;
e571cbf1 TM	464	}
	465
	466	void nfs_dns_resolver_destroy(void)
	467	{
9df69c81	468	rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
c8d74d9b	469	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
e571cbf1	470	}
c2e8139c	471	#endif