[linux-2.6-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 *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;
	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 = 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_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);
	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_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 *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;
437f9145	68	struct rcu_head rcu_head;
e571cbf1 TM	69	};
	70
	71
ebed9203 TM	72	static void nfs_dns_ent_update(struct cache_head *cnew,
	73	struct cache_head *ckey)
	74	{
	75	struct nfs_dns_ent *new;
	76	struct nfs_dns_ent *key;
	77
	78	new = container_of(cnew, struct nfs_dns_ent, h);
	79	key = container_of(ckey, struct nfs_dns_ent, h);
	80
	81	memcpy(&new->addr, &key->addr, key->addrlen);
	82	new->addrlen = key->addrlen;
	83	}
	84
e571cbf1 TM	85	static void nfs_dns_ent_init(struct cache_head *cnew,
	86	struct cache_head *ckey)
	87	{
	88	struct nfs_dns_ent *new;
	89	struct nfs_dns_ent *key;
	90
	91	new = container_of(cnew, struct nfs_dns_ent, h);
	92	key = container_of(ckey, struct nfs_dns_ent, h);
	93
	94	kfree(new->hostname);
	95	new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
	96	if (new->hostname) {
	97	new->namelen = key->namelen;
ebed9203	98	nfs_dns_ent_update(cnew, ckey);
e571cbf1 TM	99	} else {
	100	new->namelen = 0;
	101	new->addrlen = 0;
	102	}
	103	}
	104
437f9145	105	static void nfs_dns_ent_free_rcu(struct rcu_head *head)
e571cbf1 TM	106	{
	107	struct nfs_dns_ent *item;
	108
437f9145	109	item = container_of(head, struct nfs_dns_ent, rcu_head);
e571cbf1 TM	110	kfree(item->hostname);
	111	kfree(item);
	112	}
	113
437f9145 TM	114	static void nfs_dns_ent_put(struct kref *ref)
	115	{
	116	struct nfs_dns_ent *item;
	117
	118	item = container_of(ref, struct nfs_dns_ent, h.ref);
a6482733	119	call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
437f9145 TM	120	}
437f9145 TM	121
e571cbf1 TM	122	static struct cache_head *nfs_dns_ent_alloc(void)
	123	{
	124	struct nfs_dns_ent item = kmalloc(sizeof(item), GFP_KERNEL);
	125
	126	if (item != NULL) {
	127	item->hostname = NULL;
	128	item->namelen = 0;
	129	item->addrlen = 0;
	130	return &item->h;
	131	}
	132	return NULL;
	133	};
	134
	135	static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
	136	{
	137	return hash_str(key->hostname, NFS_DNS_HASHBITS);
	138	}
	139
	140	static void nfs_dns_request(struct cache_detail *cd,
	141	struct cache_head *ch,
	142	char *bpp, int blen)
	143	{
	144	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	145
	146	qword_add(bpp, blen, key->hostname);
	147	(*bpp)[-1] = '\n';
	148	}
	149
	150	static int nfs_dns_upcall(struct cache_detail *cd,
	151	struct cache_head *ch)
	152	{
	153	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
	154	int ret;
	155
	156	ret = nfs_cache_upcall(cd, key->hostname);
	157	if (ret)
21cd1254	158	ret = sunrpc_cache_pipe_upcall(cd, ch);
e571cbf1 TM	159	return ret;
	160	}
	161
	162	static int nfs_dns_match(struct cache_head *ca,
	163	struct cache_head *cb)
	164	{
	165	struct nfs_dns_ent *a;
	166	struct nfs_dns_ent *b;
	167
	168	a = container_of(ca, struct nfs_dns_ent, h);
	169	b = container_of(cb, struct nfs_dns_ent, h);
	170
	171	if (a->namelen == 0 \|\| a->namelen != b->namelen)
	172	return 0;
	173	return memcmp(a->hostname, b->hostname, a->namelen) == 0;
	174	}
	175
	176	static int nfs_dns_show(struct seq_file m, struct cache_detail cd,
	177	struct cache_head *h)
	178	{
	179	struct nfs_dns_ent *item;
	180	long ttl;
	181
	182	if (h == NULL) {
	183	seq_puts(m, "# ip address hostname ttl\n");
	184	return 0;
	185	}
	186	item = container_of(h, struct nfs_dns_ent, h);
c5b29f88	187	ttl = item->h.expiry_time - seconds_since_boot();
e571cbf1 TM	188	if (ttl < 0)
	189	ttl = 0;
	190
	191	if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
	192	char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
	193
	194	rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
	195	seq_printf(m, "%15s ", buf);
	196	} else
	197	seq_puts(m, "<none> ");
	198	seq_printf(m, "%15s %ld\n", item->hostname, ttl);
	199	return 0;
	200	}
	201
0a6566ec	202	static struct nfs_dns_ent nfs_dns_lookup(struct cache_detail cd,
e571cbf1 TM	203	struct nfs_dns_ent *key)
	204	{
	205	struct cache_head *ch;
	206
437f9145	207	ch = sunrpc_cache_lookup_rcu(cd,
e571cbf1 TM	208	&key->h,
	209	nfs_dns_hash(key));
	210	if (!ch)
	211	return NULL;
	212	return container_of(ch, struct nfs_dns_ent, h);
	213	}
	214
0a6566ec	215	static struct nfs_dns_ent nfs_dns_update(struct cache_detail cd,
e571cbf1 TM	216	struct nfs_dns_ent *new,
	217	struct nfs_dns_ent *key)
	218	{
	219	struct cache_head *ch;
	220
	221	ch = sunrpc_cache_update(cd,
	222	&new->h, &key->h,
	223	nfs_dns_hash(key));
	224	if (!ch)
	225	return NULL;
	226	return container_of(ch, struct nfs_dns_ent, h);
	227	}
	228
	229	static int nfs_dns_parse(struct cache_detail cd, char buf, int buflen)
	230	{
	231	char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
	232	struct nfs_dns_ent key, *item;
8d96b106	233	unsigned int ttl;
e571cbf1 TM	234	ssize_t len;
	235	int ret = -EINVAL;
	236
	237	if (buf[buflen-1] != '\n')
	238	goto out;
	239	buf[buflen-1] = '\0';
	240
	241	len = qword_get(&buf, buf1, sizeof(buf1));
	242	if (len <= 0)
	243	goto out;
599ec129	244	key.addrlen = rpc_pton(cd->net, buf1, len,
e571cbf1 TM	245	(struct sockaddr *)&key.addr,
	246	sizeof(key.addr));
	247
	248	len = qword_get(&buf, buf1, sizeof(buf1));
	249	if (len <= 0)
	250	goto out;
	251
	252	key.hostname = buf1;
	253	key.namelen = len;
	254	memset(&key.h, 0, sizeof(key.h));
	255
8d96b106 N	256	if (get_uint(&buf, &ttl) < 0)
8d96b106 N	257	goto out;
e571cbf1 TM	258	if (ttl == 0)
e571cbf1 TM	259	goto out;
c5b29f88	260	key.h.expiry_time = ttl + seconds_since_boot();
e571cbf1 TM	261
	262	ret = -ENOMEM;
	263	item = nfs_dns_lookup(cd, &key);
	264	if (item == NULL)
	265	goto out;
	266
	267	if (key.addrlen == 0)
	268	set_bit(CACHE_NEGATIVE, &key.h.flags);
	269
	270	item = nfs_dns_update(cd, &key, item);
	271	if (item == NULL)
	272	goto out;
	273
	274	ret = 0;
	275	cache_put(&item->h, cd);
	276	out:
	277	return ret;
	278	}
	279
e571cbf1 TM	280	static int do_cache_lookup(struct cache_detail *cd,
	281	struct nfs_dns_ent *key,
	282	struct nfs_dns_ent **item,
	283	struct nfs_cache_defer_req *dreq)
	284	{
	285	int ret = -ENOMEM;
	286
	287	*item = nfs_dns_lookup(cd, key);
	288	if (*item) {
	289	ret = cache_check(cd, &(*item)->h, &dreq->req);
	290	if (ret)
	291	*item = NULL;
	292	}
	293	return ret;
	294	}
	295
	296	static int do_cache_lookup_nowait(struct cache_detail *cd,
	297	struct nfs_dns_ent *key,
	298	struct nfs_dns_ent **item)
	299	{
	300	int ret = -ENOMEM;
	301
	302	*item = nfs_dns_lookup(cd, key);
	303	if (!*item)
	304	goto out_err;
	305	ret = -ETIMEDOUT;
	306	if (!test_bit(CACHE_VALID, &(*item)->h.flags)
c5b29f88	307	\|\| (*item)->h.expiry_time < seconds_since_boot()
e571cbf1 TM	308	\|\| cd->flush_time > (*item)->h.last_refresh)
	309	goto out_put;
	310	ret = -ENOENT;
	311	if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
	312	goto out_put;
	313	return 0;
	314	out_put:
	315	cache_put(&(*item)->h, cd);
	316	out_err:
	317	*item = NULL;
	318	return ret;
	319	}
	320
	321	static int do_cache_lookup_wait(struct cache_detail *cd,
	322	struct nfs_dns_ent *key,
	323	struct nfs_dns_ent **item)
	324	{
	325	struct nfs_cache_defer_req *dreq;
	326	int ret = -ENOMEM;
	327
	328	dreq = nfs_cache_defer_req_alloc();
	329	if (!dreq)
	330	goto out;
	331	ret = do_cache_lookup(cd, key, item, dreq);
	332	if (ret == -EAGAIN) {
	333	ret = nfs_cache_wait_for_upcall(dreq);
	334	if (!ret)
	335	ret = do_cache_lookup_nowait(cd, key, item);
	336	}
	337	nfs_cache_defer_req_put(dreq);
	338	out:
	339	return ret;
	340	}
	341
1b340d01 SK	342	ssize_t nfs_dns_resolve_name(struct net net, char name,
1b340d01 SK	343	size_t namelen, struct sockaddr *sa, size_t salen)
e571cbf1 TM	344	{
	345	struct nfs_dns_ent key = {
	346	.hostname = name,
	347	.namelen = namelen,
	348	};
	349	struct nfs_dns_ent *item = NULL;
	350	ssize_t ret;
1b340d01	351	struct nfs_net *nn = net_generic(net, nfs_net_id);
e571cbf1	352
1b340d01	353	ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
e571cbf1 TM	354	if (ret == 0) {
	355	if (salen >= item->addrlen) {
	356	memcpy(sa, &item->addr, item->addrlen);
	357	ret = item->addrlen;
	358	} else
	359	ret = -EOVERFLOW;
1b340d01	360	cache_put(&item->h, nn->nfs_dns_resolve);
e571cbf1 TM	361	} else if (ret == -ENOENT)
	362	ret = -ESRCH;
	363	return ret;
	364	}
	365
483479c2 SK	366	static struct cache_detail nfs_dns_resolve_template = {
	367	.owner = THIS_MODULE,
	368	.hash_size = NFS_DNS_HASHTBL_SIZE,
	369	.name = "dns_resolve",
	370	.cache_put = nfs_dns_ent_put,
	371	.cache_upcall = nfs_dns_upcall,
73fb847a	372	.cache_request = nfs_dns_request,
483479c2 SK	373	.cache_parse = nfs_dns_parse,
	374	.cache_show = nfs_dns_show,
	375	.match = nfs_dns_match,
	376	.init = nfs_dns_ent_init,
	377	.update = nfs_dns_ent_update,
	378	.alloc = nfs_dns_ent_alloc,
	379	};
	380
	381
1b340d01	382	int nfs_dns_resolver_cache_init(struct net *net)
e571cbf1	383	{
483479c2	384	int err;
1b340d01	385	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	386
483479c2 SK	387	nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
	388	if (IS_ERR(nn->nfs_dns_resolve))
	389	return PTR_ERR(nn->nfs_dns_resolve);
	390
483479c2	391	err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
1b340d01 SK	392	if (err)
1b340d01 SK	393	goto err_reg;
1b340d01	394	return 0;
9222b955	395
1b340d01	396	err_reg:
483479c2	397	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	398	return err;
	399	}
	400
	401	void nfs_dns_resolver_cache_destroy(struct net *net)
	402	{
	403	struct nfs_net *nn = net_generic(net, nfs_net_id);
1b340d01	404
462b8f6b	405	nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
483479c2	406	cache_destroy_net(nn->nfs_dns_resolve, net);
1b340d01 SK	407	}
1b340d01 SK	408
c8d74d9b TM	409	static int nfs4_dns_net_init(struct net *net)
	410	{
	411	return nfs_dns_resolver_cache_init(net);
	412	}
	413
	414	static void nfs4_dns_net_exit(struct net *net)
	415	{
	416	nfs_dns_resolver_cache_destroy(net);
	417	}
	418
	419	static struct pernet_operations nfs4_dns_resolver_ops = {
	420	.init = nfs4_dns_net_init,
	421	.exit = nfs4_dns_net_exit,
	422	};
	423
9df69c81 SK	424	static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
	425	void *ptr)
	426	{
	427	struct super_block *sb = ptr;
	428	struct net *net = sb->s_fs_info;
	429	struct nfs_net *nn = net_generic(net, nfs_net_id);
	430	struct cache_detail *cd = nn->nfs_dns_resolve;
	431	int ret = 0;
	432
	433	if (cd == NULL)
	434	return 0;
	435
	436	if (!try_module_get(THIS_MODULE))
	437	return 0;
	438
	439	switch (event) {
	440	case RPC_PIPEFS_MOUNT:
	441	ret = nfs_cache_register_sb(sb, cd);
	442	break;
	443	case RPC_PIPEFS_UMOUNT:
	444	nfs_cache_unregister_sb(sb, cd);
	445	break;
	446	default:
	447	ret = -ENOTSUPP;
	448	break;
	449	}
	450	module_put(THIS_MODULE);
	451	return ret;
	452	}
	453
	454	static struct notifier_block nfs_dns_resolver_block = {
	455	.notifier_call = rpc_pipefs_event,
	456	};
	457
1b340d01 SK	458	int nfs_dns_resolver_init(void)
1b340d01 SK	459	{
c8d74d9b TM	460	int err;
	461
	462	err = register_pernet_subsys(&nfs4_dns_resolver_ops);
	463	if (err < 0)
	464	goto out;
	465	err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
	466	if (err < 0)
	467	goto out1;
	468	return 0;
	469	out1:
	470	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
	471	out:
	472	return err;
e571cbf1 TM	473	}
	474
	475	void nfs_dns_resolver_destroy(void)
	476	{
9df69c81	477	rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
c8d74d9b	478	unregister_pernet_subsys(&nfs4_dns_resolver_ops);
e571cbf1	479	}
c2e8139c	480	#endif