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1/*
2 * linux/fs/nfs/dns_resolve.c
3 *
4 * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
5 *
6 * Resolves DNS hostnames into valid ip addresses
7 */
8
9#ifdef CONFIG_NFS_USE_KERNEL_DNS
10
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"
16
17ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
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)
26 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
27 else
28 ret = -ESRCH;
29 kfree(ip_addr);
30 return ret;
31}
32
33#else
34
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>
49#include <linux/nfs_fs.h>
50
51#include "nfs4_fs.h"
52#include "dns_resolve.h"
53#include "cache_lib.h"
54#include "netns.h"
55
56#define NFS_DNS_HASHBITS 4
57#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
58
59struct 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
70static 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
83static 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;
96 nfs_dns_ent_update(cnew, ckey);
97 } else {
98 new->namelen = 0;
99 new->addrlen = 0;
100 }
101}
102
103static 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
112static 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
125static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
126{
127 return hash_str(key->hostname, NFS_DNS_HASHBITS);
128}
129
130static 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
140static 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)
148 ret = sunrpc_cache_pipe_upcall(cd, ch);
149 return ret;
150}
151
152static 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
166static 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);
177 ttl = item->h.expiry_time - seconds_since_boot();
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
192static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
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
205static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
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
219static 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;
223 unsigned int ttl;
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;
234 key.addrlen = rpc_pton(cd->net, buf1, len,
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
246 if (get_uint(&buf, &ttl) < 0)
247 goto out;
248 if (ttl == 0)
249 goto out;
250 key.h.expiry_time = ttl + seconds_since_boot();
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);
266out:
267 return ret;
268}
269
270static 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
286static 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)
297 || (*item)->h.expiry_time < seconds_since_boot()
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;
304out_put:
305 cache_put(&(*item)->h, cd);
306out_err:
307 *item = NULL;
308 return ret;
309}
310
311static 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);
328out:
329 return ret;
330}
331
332ssize_t nfs_dns_resolve_name(struct net *net, char *name,
333 size_t namelen, struct sockaddr *sa, size_t salen)
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;
341 struct nfs_net *nn = net_generic(net, nfs_net_id);
342
343 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
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;
350 cache_put(&item->h, nn->nfs_dns_resolve);
351 } else if (ret == -ENOENT)
352 ret = -ESRCH;
353 return ret;
354}
355
356static 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,
362 .cache_request = nfs_dns_request,
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
372int nfs_dns_resolver_cache_init(struct net *net)
373{
374 int err;
375 struct nfs_net *nn = net_generic(net, nfs_net_id);
376
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
381 err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
382 if (err)
383 goto err_reg;
384 return 0;
385
386err_reg:
387 cache_destroy_net(nn->nfs_dns_resolve, net);
388 return err;
389}
390
391void nfs_dns_resolver_cache_destroy(struct net *net)
392{
393 struct nfs_net *nn = net_generic(net, nfs_net_id);
394
395 nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
396 cache_destroy_net(nn->nfs_dns_resolve, net);
397}
398
399static int nfs4_dns_net_init(struct net *net)
400{
401 return nfs_dns_resolver_cache_init(net);
402}
403
404static void nfs4_dns_net_exit(struct net *net)
405{
406 nfs_dns_resolver_cache_destroy(net);
407}
408
409static struct pernet_operations nfs4_dns_resolver_ops = {
410 .init = nfs4_dns_net_init,
411 .exit = nfs4_dns_net_exit,
412};
413
414static 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
444static struct notifier_block nfs_dns_resolver_block = {
445 .notifier_call = rpc_pipefs_event,
446};
447
448int nfs_dns_resolver_init(void)
449{
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;
459out1:
460 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
461out:
462 return err;
463}
464
465void nfs_dns_resolver_destroy(void)
466{
467 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
468 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
469}
470#endif
1// SPDX-License-Identifier: GPL-2.0
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
10#include <linux/module.h>
11#include <linux/sunrpc/clnt.h>
12#include <linux/sunrpc/addr.h>
13
14#include "dns_resolve.h"
15
16#ifdef CONFIG_NFS_USE_KERNEL_DNS
17
18#include <linux/dns_resolver.h>
19
20ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
21 struct sockaddr_storage *ss, size_t salen)
22{
23 struct sockaddr *sa = (struct sockaddr *)ss;
24 ssize_t ret;
25 char *ip_addr = NULL;
26 int ip_len;
27
28 ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
29 false);
30 if (ip_len > 0)
31 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
32 else
33 ret = -ESRCH;
34 kfree(ip_addr);
35 return ret;
36}
37
38#else
39
40#include <linux/hash.h>
41#include <linux/string.h>
42#include <linux/kmod.h>
43#include <linux/slab.h>
44#include <linux/socket.h>
45#include <linux/seq_file.h>
46#include <linux/inet.h>
47#include <linux/sunrpc/cache.h>
48#include <linux/sunrpc/svcauth.h>
49#include <linux/sunrpc/rpc_pipe_fs.h>
50#include <linux/nfs_fs.h>
51
52#include "nfs4_fs.h"
53#include "cache_lib.h"
54#include "netns.h"
55
56#define NFS_DNS_HASHBITS 4
57#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
58
59struct 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 struct rcu_head rcu_head;
68};
69
70
71static 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
84static 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 = kmemdup_nul(key->hostname, key->namelen, GFP_KERNEL);
95 if (new->hostname) {
96 new->namelen = key->namelen;
97 nfs_dns_ent_update(cnew, ckey);
98 } else {
99 new->namelen = 0;
100 new->addrlen = 0;
101 }
102}
103
104static void nfs_dns_ent_free_rcu(struct rcu_head *head)
105{
106 struct nfs_dns_ent *item;
107
108 item = container_of(head, struct nfs_dns_ent, rcu_head);
109 kfree(item->hostname);
110 kfree(item);
111}
112
113static void nfs_dns_ent_put(struct kref *ref)
114{
115 struct nfs_dns_ent *item;
116
117 item = container_of(ref, struct nfs_dns_ent, h.ref);
118 call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
119}
120
121static struct cache_head *nfs_dns_ent_alloc(void)
122{
123 struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);
124
125 if (item != NULL) {
126 item->hostname = NULL;
127 item->namelen = 0;
128 item->addrlen = 0;
129 return &item->h;
130 }
131 return NULL;
132};
133
134static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
135{
136 return hash_str(key->hostname, NFS_DNS_HASHBITS);
137}
138
139static void nfs_dns_request(struct cache_detail *cd,
140 struct cache_head *ch,
141 char **bpp, int *blen)
142{
143 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
144
145 qword_add(bpp, blen, key->hostname);
146 (*bpp)[-1] = '\n';
147}
148
149static int nfs_dns_upcall(struct cache_detail *cd,
150 struct cache_head *ch)
151{
152 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
153
154 if (test_and_set_bit(CACHE_PENDING, &ch->flags))
155 return 0;
156 if (!nfs_cache_upcall(cd, key->hostname))
157 return 0;
158 clear_bit(CACHE_PENDING, &ch->flags);
159 return sunrpc_cache_pipe_upcall_timeout(cd, ch);
160}
161
162static 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
176static 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);
187 ttl = item->h.expiry_time - seconds_since_boot();
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
202static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
203 struct nfs_dns_ent *key)
204{
205 struct cache_head *ch;
206
207 ch = sunrpc_cache_lookup_rcu(cd,
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
215static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
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
229static 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;
233 unsigned int ttl;
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;
244 key.addrlen = rpc_pton(cd->net, buf1, len,
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
256 if (get_uint(&buf, &ttl) < 0)
257 goto out;
258 if (ttl == 0)
259 goto out;
260 key.h.expiry_time = ttl + seconds_since_boot();
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);
276out:
277 return ret;
278}
279
280static 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
296static 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)
307 || (*item)->h.expiry_time < seconds_since_boot()
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;
314out_put:
315 cache_put(&(*item)->h, cd);
316out_err:
317 *item = NULL;
318 return ret;
319}
320
321static 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);
338out:
339 return ret;
340}
341
342ssize_t nfs_dns_resolve_name(struct net *net, char *name,
343 size_t namelen, struct sockaddr_storage *ss, size_t salen)
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;
351 struct nfs_net *nn = net_generic(net, nfs_net_id);
352
353 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
354 if (ret == 0) {
355 if (salen >= item->addrlen) {
356 memcpy(ss, &item->addr, item->addrlen);
357 ret = item->addrlen;
358 } else
359 ret = -EOVERFLOW;
360 cache_put(&item->h, nn->nfs_dns_resolve);
361 } else if (ret == -ENOENT)
362 ret = -ESRCH;
363 return ret;
364}
365
366static 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,
372 .cache_request = nfs_dns_request,
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
382int nfs_dns_resolver_cache_init(struct net *net)
383{
384 int err;
385 struct nfs_net *nn = net_generic(net, nfs_net_id);
386
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
391 err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
392 if (err)
393 goto err_reg;
394 return 0;
395
396err_reg:
397 cache_destroy_net(nn->nfs_dns_resolve, net);
398 return err;
399}
400
401void nfs_dns_resolver_cache_destroy(struct net *net)
402{
403 struct nfs_net *nn = net_generic(net, nfs_net_id);
404
405 nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
406 cache_destroy_net(nn->nfs_dns_resolve, net);
407}
408
409static int nfs4_dns_net_init(struct net *net)
410{
411 return nfs_dns_resolver_cache_init(net);
412}
413
414static void nfs4_dns_net_exit(struct net *net)
415{
416 nfs_dns_resolver_cache_destroy(net);
417}
418
419static struct pernet_operations nfs4_dns_resolver_ops = {
420 .init = nfs4_dns_net_init,
421 .exit = nfs4_dns_net_exit,
422};
423
424static 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
454static struct notifier_block nfs_dns_resolver_block = {
455 .notifier_call = rpc_pipefs_event,
456};
457
458int nfs_dns_resolver_init(void)
459{
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;
469out1:
470 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
471out:
472 return err;
473}
474
475void nfs_dns_resolver_destroy(void)
476{
477 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
478 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
479}
480#endif