2 * linux/fs/nfs/dns_resolve.c
4 * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
6 * Resolves DNS hostnames into valid ip addresses
9 #ifdef CONFIG_NFS_USE_KERNEL_DNS
11 #include <linux/module.h>
12 #include <linux/sunrpc/clnt.h>
13 #include <linux/sunrpc/addr.h>
14 #include <linux/dns_resolver.h>
15 #include "dns_resolve.h"
17 ssize_t
nfs_dns_resolve_name(struct net
*net
, char *name
, size_t namelen
,
18 struct sockaddr
*sa
, size_t salen
)
24 ip_len
= dns_query(NULL
, name
, namelen
, NULL
, &ip_addr
, NULL
);
26 ret
= rpc_pton(net
, ip_addr
, ip_len
, sa
, salen
);
35 #include <linux/module.h>
36 #include <linux/hash.h>
37 #include <linux/string.h>
38 #include <linux/kmod.h>
39 #include <linux/slab.h>
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>
45 #include <linux/sunrpc/addr.h>
46 #include <linux/sunrpc/cache.h>
47 #include <linux/sunrpc/svcauth.h>
48 #include <linux/sunrpc/rpc_pipe_fs.h>
50 #include "dns_resolve.h"
51 #include "cache_lib.h"
54 #define NFS_DNS_HASHBITS 4
55 #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
63 struct sockaddr_storage addr
;
68 static void nfs_dns_ent_update(struct cache_head
*cnew
,
69 struct cache_head
*ckey
)
71 struct nfs_dns_ent
*new;
72 struct nfs_dns_ent
*key
;
74 new = container_of(cnew
, struct nfs_dns_ent
, h
);
75 key
= container_of(ckey
, struct nfs_dns_ent
, h
);
77 memcpy(&new->addr
, &key
->addr
, key
->addrlen
);
78 new->addrlen
= key
->addrlen
;
81 static void nfs_dns_ent_init(struct cache_head
*cnew
,
82 struct cache_head
*ckey
)
84 struct nfs_dns_ent
*new;
85 struct nfs_dns_ent
*key
;
87 new = container_of(cnew
, struct nfs_dns_ent
, h
);
88 key
= container_of(ckey
, struct nfs_dns_ent
, h
);
91 new->hostname
= kstrndup(key
->hostname
, key
->namelen
, GFP_KERNEL
);
93 new->namelen
= key
->namelen
;
94 nfs_dns_ent_update(cnew
, ckey
);
101 static void nfs_dns_ent_put(struct kref
*ref
)
103 struct nfs_dns_ent
*item
;
105 item
= container_of(ref
, struct nfs_dns_ent
, h
.ref
);
106 kfree(item
->hostname
);
110 static struct cache_head
*nfs_dns_ent_alloc(void)
112 struct nfs_dns_ent
*item
= kmalloc(sizeof(*item
), GFP_KERNEL
);
115 item
->hostname
= NULL
;
123 static unsigned int nfs_dns_hash(const struct nfs_dns_ent
*key
)
125 return hash_str(key
->hostname
, NFS_DNS_HASHBITS
);
128 static void nfs_dns_request(struct cache_detail
*cd
,
129 struct cache_head
*ch
,
130 char **bpp
, int *blen
)
132 struct nfs_dns_ent
*key
= container_of(ch
, struct nfs_dns_ent
, h
);
134 qword_add(bpp
, blen
, key
->hostname
);
138 static int nfs_dns_upcall(struct cache_detail
*cd
,
139 struct cache_head
*ch
)
141 struct nfs_dns_ent
*key
= container_of(ch
, struct nfs_dns_ent
, h
);
144 ret
= nfs_cache_upcall(cd
, key
->hostname
);
146 ret
= sunrpc_cache_pipe_upcall(cd
, ch
);
150 static int nfs_dns_match(struct cache_head
*ca
,
151 struct cache_head
*cb
)
153 struct nfs_dns_ent
*a
;
154 struct nfs_dns_ent
*b
;
156 a
= container_of(ca
, struct nfs_dns_ent
, h
);
157 b
= container_of(cb
, struct nfs_dns_ent
, h
);
159 if (a
->namelen
== 0 || a
->namelen
!= b
->namelen
)
161 return memcmp(a
->hostname
, b
->hostname
, a
->namelen
) == 0;
164 static int nfs_dns_show(struct seq_file
*m
, struct cache_detail
*cd
,
165 struct cache_head
*h
)
167 struct nfs_dns_ent
*item
;
171 seq_puts(m
, "# ip address hostname ttl\n");
174 item
= container_of(h
, struct nfs_dns_ent
, h
);
175 ttl
= item
->h
.expiry_time
- seconds_since_boot();
179 if (!test_bit(CACHE_NEGATIVE
, &h
->flags
)) {
180 char buf
[INET6_ADDRSTRLEN
+IPV6_SCOPE_ID_LEN
+1];
182 rpc_ntop((struct sockaddr
*)&item
->addr
, buf
, sizeof(buf
));
183 seq_printf(m
, "%15s ", buf
);
185 seq_puts(m
, "<none> ");
186 seq_printf(m
, "%15s %ld\n", item
->hostname
, ttl
);
190 static struct nfs_dns_ent
*nfs_dns_lookup(struct cache_detail
*cd
,
191 struct nfs_dns_ent
*key
)
193 struct cache_head
*ch
;
195 ch
= sunrpc_cache_lookup(cd
,
200 return container_of(ch
, struct nfs_dns_ent
, h
);
203 static struct nfs_dns_ent
*nfs_dns_update(struct cache_detail
*cd
,
204 struct nfs_dns_ent
*new,
205 struct nfs_dns_ent
*key
)
207 struct cache_head
*ch
;
209 ch
= sunrpc_cache_update(cd
,
214 return container_of(ch
, struct nfs_dns_ent
, h
);
217 static int nfs_dns_parse(struct cache_detail
*cd
, char *buf
, int buflen
)
219 char buf1
[NFS_DNS_HOSTNAME_MAXLEN
+1];
220 struct nfs_dns_ent key
, *item
;
225 if (buf
[buflen
-1] != '\n')
227 buf
[buflen
-1] = '\0';
229 len
= qword_get(&buf
, buf1
, sizeof(buf1
));
232 key
.addrlen
= rpc_pton(cd
->net
, buf1
, len
,
233 (struct sockaddr
*)&key
.addr
,
236 len
= qword_get(&buf
, buf1
, sizeof(buf1
));
242 memset(&key
.h
, 0, sizeof(key
.h
));
244 if (get_uint(&buf
, &ttl
) < 0)
248 key
.h
.expiry_time
= ttl
+ seconds_since_boot();
251 item
= nfs_dns_lookup(cd
, &key
);
255 if (key
.addrlen
== 0)
256 set_bit(CACHE_NEGATIVE
, &key
.h
.flags
);
258 item
= nfs_dns_update(cd
, &key
, item
);
263 cache_put(&item
->h
, cd
);
268 static int do_cache_lookup(struct cache_detail
*cd
,
269 struct nfs_dns_ent
*key
,
270 struct nfs_dns_ent
**item
,
271 struct nfs_cache_defer_req
*dreq
)
275 *item
= nfs_dns_lookup(cd
, key
);
277 ret
= cache_check(cd
, &(*item
)->h
, &dreq
->req
);
284 static int do_cache_lookup_nowait(struct cache_detail
*cd
,
285 struct nfs_dns_ent
*key
,
286 struct nfs_dns_ent
**item
)
290 *item
= nfs_dns_lookup(cd
, key
);
294 if (!test_bit(CACHE_VALID
, &(*item
)->h
.flags
)
295 || (*item
)->h
.expiry_time
< seconds_since_boot()
296 || cd
->flush_time
> (*item
)->h
.last_refresh
)
299 if (test_bit(CACHE_NEGATIVE
, &(*item
)->h
.flags
))
303 cache_put(&(*item
)->h
, cd
);
309 static int do_cache_lookup_wait(struct cache_detail
*cd
,
310 struct nfs_dns_ent
*key
,
311 struct nfs_dns_ent
**item
)
313 struct nfs_cache_defer_req
*dreq
;
316 dreq
= nfs_cache_defer_req_alloc();
319 ret
= do_cache_lookup(cd
, key
, item
, dreq
);
320 if (ret
== -EAGAIN
) {
321 ret
= nfs_cache_wait_for_upcall(dreq
);
323 ret
= do_cache_lookup_nowait(cd
, key
, item
);
325 nfs_cache_defer_req_put(dreq
);
330 ssize_t
nfs_dns_resolve_name(struct net
*net
, char *name
,
331 size_t namelen
, struct sockaddr
*sa
, size_t salen
)
333 struct nfs_dns_ent key
= {
337 struct nfs_dns_ent
*item
= NULL
;
339 struct nfs_net
*nn
= net_generic(net
, nfs_net_id
);
341 ret
= do_cache_lookup_wait(nn
->nfs_dns_resolve
, &key
, &item
);
343 if (salen
>= item
->addrlen
) {
344 memcpy(sa
, &item
->addr
, item
->addrlen
);
348 cache_put(&item
->h
, nn
->nfs_dns_resolve
);
349 } else if (ret
== -ENOENT
)
354 static struct cache_detail nfs_dns_resolve_template
= {
355 .owner
= THIS_MODULE
,
356 .hash_size
= NFS_DNS_HASHTBL_SIZE
,
357 .name
= "dns_resolve",
358 .cache_put
= nfs_dns_ent_put
,
359 .cache_upcall
= nfs_dns_upcall
,
360 .cache_request
= nfs_dns_request
,
361 .cache_parse
= nfs_dns_parse
,
362 .cache_show
= nfs_dns_show
,
363 .match
= nfs_dns_match
,
364 .init
= nfs_dns_ent_init
,
365 .update
= nfs_dns_ent_update
,
366 .alloc
= nfs_dns_ent_alloc
,
370 int nfs_dns_resolver_cache_init(struct net
*net
)
373 struct nfs_net
*nn
= net_generic(net
, nfs_net_id
);
375 nn
->nfs_dns_resolve
= cache_create_net(&nfs_dns_resolve_template
, net
);
376 if (IS_ERR(nn
->nfs_dns_resolve
))
377 return PTR_ERR(nn
->nfs_dns_resolve
);
379 err
= nfs_cache_register_net(net
, nn
->nfs_dns_resolve
);
385 cache_destroy_net(nn
->nfs_dns_resolve
, net
);
389 void nfs_dns_resolver_cache_destroy(struct net
*net
)
391 struct nfs_net
*nn
= net_generic(net
, nfs_net_id
);
393 nfs_cache_unregister_net(net
, nn
->nfs_dns_resolve
);
394 cache_destroy_net(nn
->nfs_dns_resolve
, net
);
397 static int nfs4_dns_net_init(struct net
*net
)
399 return nfs_dns_resolver_cache_init(net
);
402 static void nfs4_dns_net_exit(struct net
*net
)
404 nfs_dns_resolver_cache_destroy(net
);
407 static struct pernet_operations nfs4_dns_resolver_ops
= {
408 .init
= nfs4_dns_net_init
,
409 .exit
= nfs4_dns_net_exit
,
412 static int rpc_pipefs_event(struct notifier_block
*nb
, unsigned long event
,
415 struct super_block
*sb
= ptr
;
416 struct net
*net
= sb
->s_fs_info
;
417 struct nfs_net
*nn
= net_generic(net
, nfs_net_id
);
418 struct cache_detail
*cd
= nn
->nfs_dns_resolve
;
424 if (!try_module_get(THIS_MODULE
))
428 case RPC_PIPEFS_MOUNT
:
429 ret
= nfs_cache_register_sb(sb
, cd
);
431 case RPC_PIPEFS_UMOUNT
:
432 nfs_cache_unregister_sb(sb
, cd
);
438 module_put(THIS_MODULE
);
442 static struct notifier_block nfs_dns_resolver_block
= {
443 .notifier_call
= rpc_pipefs_event
,
446 int nfs_dns_resolver_init(void)
450 err
= register_pernet_subsys(&nfs4_dns_resolver_ops
);
453 err
= rpc_pipefs_notifier_register(&nfs_dns_resolver_block
);
458 unregister_pernet_subsys(&nfs4_dns_resolver_ops
);
463 void nfs_dns_resolver_destroy(void)
465 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block
);
466 unregister_pernet_subsys(&nfs4_dns_resolver_ops
);