[linux-block.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_storage *ss, size_t salen)
{
	struct sockaddr *sa = (struct sockaddr *)ss;
	ssize_t ret;
	char *ip_addr = NULL;
	int ip_len;

	ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
			   false);
	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/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;
	struct rcu_head rcu_head;
};


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 = kmemdup_nul(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_free_rcu(struct rcu_head *head)
{
	struct nfs_dns_ent *item;

	item = container_of(head, struct nfs_dns_ent, rcu_head);
	kfree(item->hostname);
	kfree(item);
}

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

	item = container_of(ref, struct nfs_dns_ent, h.ref);
	call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
}

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);

	if (test_and_set_bit(CACHE_PENDING, &ch->flags))
		return 0;
	if (!nfs_cache_upcall(cd, key->hostname))
		return 0;
	clear_bit(CACHE_PENDING, &ch->flags);
	return sunrpc_cache_pipe_upcall_timeout(cd, ch);
}

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_rcu(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_storage *ss, 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(ss, &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,
cf0d7e7f	19	struct sockaddr_storage *ss, size_t salen)
c2e8139c	20	{
cf0d7e7f	21	struct sockaddr sa = (struct sockaddr )ss;
c2e8139c BS	22	ssize_t ret;
	23	char *ip_addr = NULL;
	24	int ip_len;
	25
a58946c1 DH	26	ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
a58946c1 DH	27	false);
c2e8139c	28	if (ip_len > 0)
bc224f53	29	ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
c2e8139c BS	30	else
	31	ret = -ESRCH;
	32	kfree(ip_addr);
	33	return ret;
	34	}
	35
	36	#else
	37
89d77c8f	38	#include <linux/module.h>
e571cbf1 TM	39	#include <linux/hash.h>
	40	#include <linux/string.h>
	41	#include <linux/kmod.h>
5a0e3ad6	42	#include <linux/slab.h>
e571cbf1 TM	43	#include <linux/socket.h>
	44	#include <linux/seq_file.h>
	45	#include <linux/inet.h>
	46	#include <linux/sunrpc/clnt.h>
5976687a	47	#include <linux/sunrpc/addr.h>
e571cbf1 TM	48	#include <linux/sunrpc/cache.h>
e571cbf1 TM	49	#include <linux/sunrpc/svcauth.h>
9df69c81	50	#include <linux/sunrpc/rpc_pipe_fs.h>
694e096f	51	#include <linux/nfs_fs.h>
e571cbf1	52
694e096f	53	#include "nfs4_fs.h"
e571cbf1 TM	54	#include "dns_resolve.h"
e571cbf1 TM	55	#include "cache_lib.h"
1b340d01	56	#include "netns.h"
e571cbf1 TM	57
	58	#define NFS_DNS_HASHBITS 4
	59	#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
	60
e571cbf1 TM	61	struct nfs_dns_ent {
	62	struct cache_head h;
	63
	64	char *hostname;
	65	size_t namelen;
	66
	67	struct sockaddr_storage addr;
	68	size_t addrlen;
437f9145	69	struct rcu_head rcu_head;
e571cbf1 TM	70	};
	71
	72
ebed9203 TM	73	static void nfs_dns_ent_update(struct cache_head *cnew,
	74	struct cache_head *ckey)
	75	{
	76	struct nfs_dns_ent *new;
	77	struct nfs_dns_ent *key;
	78
	79	new = container_of(cnew, struct nfs_dns_ent, h);
	80	key = container_of(ckey, struct nfs_dns_ent, h);
	81
	82	memcpy(&new->addr, &key->addr, key->addrlen);
	83	new->addrlen = key->addrlen;
	84	}
	85
e571cbf1 TM	86	static void nfs_dns_ent_init(struct cache_head *cnew,
	87	struct cache_head *ckey)
	88	{
	89	struct nfs_dns_ent *new;
	90	struct nfs_dns_ent *key;
	91
	92	new = container_of(cnew, struct nfs_dns_ent, h);
	93	key = container_of(ckey, struct nfs_dns_ent, h);
	94
	95	kfree(new->hostname);
a8bd9ddf	96	new->hostname = kmemdup_nul(key->hostname, key->namelen, GFP_KERNEL);
e571cbf1 TM	97	if (new->hostname) {
e571cbf1 TM	98	new->namelen = key->namelen;
ebed9203	99	nfs_dns_ent_update(cnew, ckey);
e571cbf1 TM	100	} else {
	101	new->namelen = 0;
	102	new->addrlen = 0;
	103	}
	104	}
	105
437f9145	106	static void nfs_dns_ent_free_rcu(struct rcu_head *head)
e571cbf1 TM	107	{
	108	struct nfs_dns_ent *item;
	109
437f9145	110	item = container_of(head, struct nfs_dns_ent, rcu_head);
e571cbf1 TM	111	kfree(item->hostname);
	112	kfree(item);
	113	}
	114
437f9145 TM	115	static void nfs_dns_ent_put(struct kref *ref)
	116	{
	117	struct nfs_dns_ent *item;
	118
	119	item = container_of(ref, struct nfs_dns_ent, h.ref);
a6482733	120	call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
437f9145 TM	121	}
437f9145 TM	122
e571cbf1 TM	123	static struct cache_head *nfs_dns_ent_alloc(void)
	124	{
	125	struct nfs_dns_ent item = kmalloc(sizeof(item), GFP_KERNEL);
	126
	127	if (item != NULL) {
	128	item->hostname = NULL;
	129	item->namelen = 0;
	130	item->addrlen = 0;
	131	return &item->h;
	132	}
	133	return NULL;
	134	};
	135
	136	static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
	137	{
	138	return hash_str(key->hostname, NFS_DNS_HASHBITS);
	139	}
	140
	141	static void nfs_dns_request(struct cache_detail *cd,
	142	struct cache_head *ch,
	143	char *bpp, int blen)
	144	{
	145	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	146
	147	qword_add(bpp, blen, key->hostname);
	148	(*bpp)[-1] = '\n';
	149	}
	150
	151	static int nfs_dns_upcall(struct cache_detail *cd,
	152	struct cache_head *ch)
	153	{
	154	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
e571cbf1	155
65286b88 TM	156	if (test_and_set_bit(CACHE_PENDING, &ch->flags))
	157	return 0;
	158	if (!nfs_cache_upcall(cd, key->hostname))
	159	return 0;
	160	clear_bit(CACHE_PENDING, &ch->flags);
	161	return sunrpc_cache_pipe_upcall_timeout(cd, ch);
e571cbf1 TM	162	}
	163
	164	static int nfs_dns_match(struct cache_head *ca,
	165	struct cache_head *cb)
	166	{
	167	struct nfs_dns_ent *a;
	168	struct nfs_dns_ent *b;
	169
	170	a = container_of(ca, struct nfs_dns_ent, h);
	171	b = container_of(cb, struct nfs_dns_ent, h);
	172
	173	if (a->namelen == 0 \|\| a->namelen != b->namelen)
	174	return 0;
	175	return memcmp(a->hostname, b->hostname, a->namelen) == 0;
	176	}
	177
	178	static int nfs_dns_show(struct seq_file m, struct cache_detail cd,
	179	struct cache_head *h)
	180	{
	181	struct nfs_dns_ent *item;
	182	long ttl;
	183
	184	if (h == NULL) {
	185	seq_puts(m, "# ip address hostname ttl\n");
	186	return 0;
	187	}
	188	item = container_of(h, struct nfs_dns_ent, h);
c5b29f88	189	ttl = item->h.expiry_time - seconds_since_boot();
e571cbf1 TM	190	if (ttl < 0)
	191	ttl = 0;
	192
	193	if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
	194	char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
	195
	196	rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
	197	seq_printf(m, "%15s ", buf);
	198	} else
	199	seq_puts(m, "<none> ");
	200	seq_printf(m, "%15s %ld\n", item->hostname, ttl);
	201	return 0;
	202	}
	203
0a6566ec	204	static struct nfs_dns_ent nfs_dns_lookup(struct cache_detail cd,
e571cbf1 TM	205	struct nfs_dns_ent *key)
	206	{
	207	struct cache_head *ch;
	208
437f9145	209	ch = sunrpc_cache_lookup_rcu(cd,
e571cbf1 TM	210	&key->h,
	211	nfs_dns_hash(key));
	212	if (!ch)
	213	return NULL;
	214	return container_of(ch, struct nfs_dns_ent, h);
	215	}
	216
0a6566ec	217	static struct nfs_dns_ent nfs_dns_update(struct cache_detail cd,
e571cbf1 TM	218	struct nfs_dns_ent *new,
	219	struct nfs_dns_ent *key)
	220	{
	221	struct cache_head *ch;
	222
	223	ch = sunrpc_cache_update(cd,
	224	&new->h, &key->h,
	225	nfs_dns_hash(key));
	226	if (!ch)
	227	return NULL;
	228	return container_of(ch, struct nfs_dns_ent, h);
	229	}
	230
	231	static int nfs_dns_parse(struct cache_detail cd, char buf, int buflen)
	232	{
	233	char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
	234	struct nfs_dns_ent key, *item;
8d96b106	235	unsigned int ttl;
e571cbf1 TM	236	ssize_t len;
	237	int ret = -EINVAL;
	238
	239	if (buf[buflen-1] != '\n')
	240	goto out;
	241	buf[buflen-1] = '\0';
	242
	243	len = qword_get(&buf, buf1, sizeof(buf1));
	244	if (len <= 0)
	245	goto out;
599ec129	246	key.addrlen = rpc_pton(cd->net, buf1, len,
e571cbf1 TM	247	(struct sockaddr *)&key.addr,
	248	sizeof(key.addr));
	249
	250	len = qword_get(&buf, buf1, sizeof(buf1));
	251	if (len <= 0)
	252	goto out;
	253
	254	key.hostname = buf1;
	255	key.namelen = len;
	256	memset(&key.h, 0, sizeof(key.h));
	257
8d96b106 N	258	if (get_uint(&buf, &ttl) < 0)
8d96b106 N	259	goto out;
e571cbf1 TM	260	if (ttl == 0)
e571cbf1 TM	261	goto out;
c5b29f88	262	key.h.expiry_time = ttl + seconds_since_boot();
e571cbf1 TM	263
	264	ret = -ENOMEM;
	265	item = nfs_dns_lookup(cd, &key);
	266	if (item == NULL)
	267	goto out;
	268
	269	if (key.addrlen == 0)
	270	set_bit(CACHE_NEGATIVE, &key.h.flags);
	271
	272	item = nfs_dns_update(cd, &key, item);
	273	if (item == NULL)
	274	goto out;
	275
	276	ret = 0;
	277	cache_put(&item->h, cd);
	278	out:
	279	return ret;
	280	}
	281
e571cbf1 TM	282	static int do_cache_lookup(struct cache_detail *cd,
	283	struct nfs_dns_ent *key,
	284	struct nfs_dns_ent **item,
	285	struct nfs_cache_defer_req *dreq)
	286	{
	287	int ret = -ENOMEM;
	288
	289	*item = nfs_dns_lookup(cd, key);
	290	if (*item) {
	291	ret = cache_check(cd, &(*item)->h, &dreq->req);
	292	if (ret)
	293	*item = NULL;
	294	}
	295	return ret;
	296	}
	297
	298	static int do_cache_lookup_nowait(struct cache_detail *cd,
	299	struct nfs_dns_ent *key,
	300	struct nfs_dns_ent **item)
	301	{
	302	int ret = -ENOMEM;
	303
	304	*item = nfs_dns_lookup(cd, key);
	305	if (!*item)
	306	goto out_err;
	307	ret = -ETIMEDOUT;
	308	if (!test_bit(CACHE_VALID, &(*item)->h.flags)
c5b29f88	309	\|\| (*item)->h.expiry_time < seconds_since_boot()
e571cbf1 TM	310	\|\| cd->flush_time > (*item)->h.last_refresh)
	311	goto out_put;
	312	ret = -ENOENT;
	313	if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
	314	goto out_put;
	315	return 0;
	316	out_put:
	317	cache_put(&(*item)->h, cd);
	318	out_err:
	319	*item = NULL;
	320	return ret;
	321	}
	322
	323	static int do_cache_lookup_wait(struct cache_detail *cd,
	324	struct nfs_dns_ent *key,
	325	struct nfs_dns_ent **item)
	326	{
	327	struct nfs_cache_defer_req *dreq;
	328	int ret = -ENOMEM;
	329
	330	dreq = nfs_cache_defer_req_alloc();
	331	if (!dreq)
	332	goto out;
	333	ret = do_cache_lookup(cd, key, item, dreq);
	334	if (ret == -EAGAIN) {
	335	ret = nfs_cache_wait_for_upcall(dreq);
	336	if (!ret)
	337	ret = do_cache_lookup_nowait(cd, key, item);
	338	}
	339	nfs_cache_defer_req_put(dreq);
	340	out:
	341	return ret;
	342	}
	343
1b340d01	344	ssize_t nfs_dns_resolve_name(struct net net, char name,
cf0d7e7f	345	size_t namelen, struct sockaddr_storage *ss, size_t salen)
e571cbf1 TM	346	{
	347	struct nfs_dns_ent key = {
	348	.hostname = name,
	349	.namelen = namelen,
	350	};
	351	struct nfs_dns_ent *item = NULL;
	352	ssize_t ret;
1b340d01	353	struct nfs_net *nn = net_generic(net, nfs_net_id);
e571cbf1	354
1b340d01	355	ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
e571cbf1 TM	356	if (ret == 0) {
e571cbf1 TM	357	if (salen >= item->addrlen) {
cf0d7e7f	358	memcpy(ss, &item->addr, item->addrlen);
e571cbf1 TM	359	ret = item->addrlen;
	360	} else
	361	ret = -EOVERFLOW;
1b340d01	362	cache_put(&item->h, nn->nfs_dns_resolve);
e571cbf1 TM	363	} else if (ret == -ENOENT)
	364	ret = -ESRCH;
	365	return ret;
	366	}
	367
483479c2 SK	368	static struct cache_detail nfs_dns_resolve_template = {
	369	.owner = THIS_MODULE,
	370	.hash_size = NFS_DNS_HASHTBL_SIZE,
	371	.name = "dns_resolve",
	372	.cache_put = nfs_dns_ent_put,
	373	.cache_upcall = nfs_dns_upcall,
73fb847a	374	.cache_request = nfs_dns_request,
483479c2 SK	375	.cache_parse = nfs_dns_parse,
	376	.cache_show = nfs_dns_show,
	377	.match = nfs_dns_match,
	378	.init = nfs_dns_ent_init,
	379	.update = nfs_dns_ent_update,
	380	.alloc = nfs_dns_ent_alloc,
	381	};
	382
	383
1b340d01	384	int nfs_dns_resolver_cache_init(struct net *net)
e571cbf1	385	{
483479c2	386	int err;
1b340d01	387	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	388
483479c2 SK	389	nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
	390	if (IS_ERR(nn->nfs_dns_resolve))
	391	return PTR_ERR(nn->nfs_dns_resolve);
	392
483479c2	393	err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
1b340d01 SK	394	if (err)
1b340d01 SK	395	goto err_reg;
1b340d01	396	return 0;
9222b955	397
1b340d01	398	err_reg:
483479c2	399	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	400	return err;
	401	}
	402
	403	void nfs_dns_resolver_cache_destroy(struct net *net)
	404	{
	405	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	406
462b8f6b	407	nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
483479c2	408	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	409	}
1b340d01 SK	410
c8d74d9b TM	411	static int nfs4_dns_net_init(struct net *net)
	412	{
	413	return nfs_dns_resolver_cache_init(net);
	414	}
	415
	416	static void nfs4_dns_net_exit(struct net *net)
	417	{
	418	nfs_dns_resolver_cache_destroy(net);
	419	}
	420
	421	static struct pernet_operations nfs4_dns_resolver_ops = {
	422	.init = nfs4_dns_net_init,
	423	.exit = nfs4_dns_net_exit,
	424	};
	425
9df69c81 SK	426	static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
	427	void *ptr)
	428	{
	429	struct super_block *sb = ptr;
	430	struct net *net = sb->s_fs_info;
	431	struct nfs_net *nn = net_generic(net, nfs_net_id);
	432	struct cache_detail *cd = nn->nfs_dns_resolve;
	433	int ret = 0;
	434
	435	if (cd == NULL)
	436	return 0;
	437
	438	if (!try_module_get(THIS_MODULE))
	439	return 0;
	440
	441	switch (event) {
	442	case RPC_PIPEFS_MOUNT:
	443	ret = nfs_cache_register_sb(sb, cd);
	444	break;
	445	case RPC_PIPEFS_UMOUNT:
	446	nfs_cache_unregister_sb(sb, cd);
	447	break;
	448	default:
	449	ret = -ENOTSUPP;
	450	break;
	451	}
	452	module_put(THIS_MODULE);
	453	return ret;
	454	}
	455
	456	static struct notifier_block nfs_dns_resolver_block = {
	457	.notifier_call = rpc_pipefs_event,
	458	};
	459
1b340d01 SK	460	int nfs_dns_resolver_init(void)
1b340d01 SK	461	{
c8d74d9b TM	462	int err;
	463
	464	err = register_pernet_subsys(&nfs4_dns_resolver_ops);
	465	if (err < 0)
	466	goto out;
	467	err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
	468	if (err < 0)
	469	goto out1;
	470	return 0;
	471	out1:
	472	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
	473	out:
	474	return err;
e571cbf1 TM	475	}
	476
	477	void nfs_dns_resolver_destroy(void)
	478	{
9df69c81	479	rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
c8d74d9b	480	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
e571cbf1	481	}
c2e8139c	482	#endif