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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#ifdef CONFIG_NFS_USE_KERNEL_DNS
11
12#include <linux/module.h>
13#include <linux/sunrpc/clnt.h>
14#include <linux/sunrpc/addr.h>
15#include <linux/dns_resolver.h>
16#include "dns_resolve.h"
17
18ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
19 struct sockaddr_storage *ss, size_t salen)
20{
21 struct sockaddr *sa = (struct sockaddr *)ss;
22 ssize_t ret;
23 char *ip_addr = NULL;
24 int ip_len;
25
26 ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
27 false);
28 if (ip_len > 0)
29 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
30 else
31 ret = -ESRCH;
32 kfree(ip_addr);
33 return ret;
34}
35
36#else
37
38#include <linux/module.h>
39#include <linux/hash.h>
40#include <linux/string.h>
41#include <linux/kmod.h>
42#include <linux/slab.h>
43#include <linux/socket.h>
44#include <linux/seq_file.h>
45#include <linux/inet.h>
46#include <linux/sunrpc/clnt.h>
47#include <linux/sunrpc/addr.h>
48#include <linux/sunrpc/cache.h>
49#include <linux/sunrpc/svcauth.h>
50#include <linux/sunrpc/rpc_pipe_fs.h>
51#include <linux/nfs_fs.h>
52
53#include "nfs4_fs.h"
54#include "dns_resolve.h"
55#include "cache_lib.h"
56#include "netns.h"
57
58#define NFS_DNS_HASHBITS 4
59#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
60
61struct 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;
69 struct rcu_head rcu_head;
70};
71
72
73static 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
86static 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);
96 new->hostname = kmemdup_nul(key->hostname, key->namelen, GFP_KERNEL);
97 if (new->hostname) {
98 new->namelen = key->namelen;
99 nfs_dns_ent_update(cnew, ckey);
100 } else {
101 new->namelen = 0;
102 new->addrlen = 0;
103 }
104}
105
106static void nfs_dns_ent_free_rcu(struct rcu_head *head)
107{
108 struct nfs_dns_ent *item;
109
110 item = container_of(head, struct nfs_dns_ent, rcu_head);
111 kfree(item->hostname);
112 kfree(item);
113}
114
115static 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);
120 call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
121}
122
123static 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
136static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
137{
138 return hash_str(key->hostname, NFS_DNS_HASHBITS);
139}
140
141static 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
151static 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);
155
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);
162}
163
164static 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
178static 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);
189 ttl = item->h.expiry_time - seconds_since_boot();
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
204static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
205 struct nfs_dns_ent *key)
206{
207 struct cache_head *ch;
208
209 ch = sunrpc_cache_lookup_rcu(cd,
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
217static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
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
231static 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;
235 unsigned int ttl;
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;
246 key.addrlen = rpc_pton(cd->net, buf1, len,
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
258 if (get_uint(&buf, &ttl) < 0)
259 goto out;
260 if (ttl == 0)
261 goto out;
262 key.h.expiry_time = ttl + seconds_since_boot();
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);
278out:
279 return ret;
280}
281
282static 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
298static 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)
309 || (*item)->h.expiry_time < seconds_since_boot()
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;
316out_put:
317 cache_put(&(*item)->h, cd);
318out_err:
319 *item = NULL;
320 return ret;
321}
322
323static 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);
340out:
341 return ret;
342}
343
344ssize_t nfs_dns_resolve_name(struct net *net, char *name,
345 size_t namelen, struct sockaddr_storage *ss, size_t salen)
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;
353 struct nfs_net *nn = net_generic(net, nfs_net_id);
354
355 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
356 if (ret == 0) {
357 if (salen >= item->addrlen) {
358 memcpy(ss, &item->addr, item->addrlen);
359 ret = item->addrlen;
360 } else
361 ret = -EOVERFLOW;
362 cache_put(&item->h, nn->nfs_dns_resolve);
363 } else if (ret == -ENOENT)
364 ret = -ESRCH;
365 return ret;
366}
367
368static 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,
374 .cache_request = nfs_dns_request,
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
384int nfs_dns_resolver_cache_init(struct net *net)
385{
386 int err;
387 struct nfs_net *nn = net_generic(net, nfs_net_id);
388
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
393 err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
394 if (err)
395 goto err_reg;
396 return 0;
397
398err_reg:
399 cache_destroy_net(nn->nfs_dns_resolve, net);
400 return err;
401}
402
403void nfs_dns_resolver_cache_destroy(struct net *net)
404{
405 struct nfs_net *nn = net_generic(net, nfs_net_id);
406
407 nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
408 cache_destroy_net(nn->nfs_dns_resolve, net);
409}
410
411static int nfs4_dns_net_init(struct net *net)
412{
413 return nfs_dns_resolver_cache_init(net);
414}
415
416static void nfs4_dns_net_exit(struct net *net)
417{
418 nfs_dns_resolver_cache_destroy(net);
419}
420
421static struct pernet_operations nfs4_dns_resolver_ops = {
422 .init = nfs4_dns_net_init,
423 .exit = nfs4_dns_net_exit,
424};
425
426static 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
456static struct notifier_block nfs_dns_resolver_block = {
457 .notifier_call = rpc_pipefs_event,
458};
459
460int nfs_dns_resolver_init(void)
461{
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;
471out1:
472 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
473out:
474 return err;
475}
476
477void nfs_dns_resolver_destroy(void)
478{
479 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
480 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
481}
482#endif
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/sunrpc/clnt.h>
12#include <linux/dns_resolver.h>
13#include "dns_resolve.h"
14
15ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
16 struct sockaddr *sa, size_t salen)
17{
18 ssize_t ret;
19 char *ip_addr = NULL;
20 int ip_len;
21
22 ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);
23 if (ip_len > 0)
24 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
25 else
26 ret = -ESRCH;
27 kfree(ip_addr);
28 return ret;
29}
30
31#else
32
33#include <linux/hash.h>
34#include <linux/string.h>
35#include <linux/kmod.h>
36#include <linux/slab.h>
37#include <linux/module.h>
38#include <linux/socket.h>
39#include <linux/seq_file.h>
40#include <linux/inet.h>
41#include <linux/sunrpc/clnt.h>
42#include <linux/sunrpc/cache.h>
43#include <linux/sunrpc/svcauth.h>
44#include <linux/sunrpc/rpc_pipe_fs.h>
45
46#include "dns_resolve.h"
47#include "cache_lib.h"
48#include "netns.h"
49
50#define NFS_DNS_HASHBITS 4
51#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
52
53struct nfs_dns_ent {
54 struct cache_head h;
55
56 char *hostname;
57 size_t namelen;
58
59 struct sockaddr_storage addr;
60 size_t addrlen;
61};
62
63
64static void nfs_dns_ent_update(struct cache_head *cnew,
65 struct cache_head *ckey)
66{
67 struct nfs_dns_ent *new;
68 struct nfs_dns_ent *key;
69
70 new = container_of(cnew, struct nfs_dns_ent, h);
71 key = container_of(ckey, struct nfs_dns_ent, h);
72
73 memcpy(&new->addr, &key->addr, key->addrlen);
74 new->addrlen = key->addrlen;
75}
76
77static void nfs_dns_ent_init(struct cache_head *cnew,
78 struct cache_head *ckey)
79{
80 struct nfs_dns_ent *new;
81 struct nfs_dns_ent *key;
82
83 new = container_of(cnew, struct nfs_dns_ent, h);
84 key = container_of(ckey, struct nfs_dns_ent, h);
85
86 kfree(new->hostname);
87 new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
88 if (new->hostname) {
89 new->namelen = key->namelen;
90 nfs_dns_ent_update(cnew, ckey);
91 } else {
92 new->namelen = 0;
93 new->addrlen = 0;
94 }
95}
96
97static void nfs_dns_ent_put(struct kref *ref)
98{
99 struct nfs_dns_ent *item;
100
101 item = container_of(ref, struct nfs_dns_ent, h.ref);
102 kfree(item->hostname);
103 kfree(item);
104}
105
106static struct cache_head *nfs_dns_ent_alloc(void)
107{
108 struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);
109
110 if (item != NULL) {
111 item->hostname = NULL;
112 item->namelen = 0;
113 item->addrlen = 0;
114 return &item->h;
115 }
116 return NULL;
117};
118
119static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
120{
121 return hash_str(key->hostname, NFS_DNS_HASHBITS);
122}
123
124static void nfs_dns_request(struct cache_detail *cd,
125 struct cache_head *ch,
126 char **bpp, int *blen)
127{
128 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
129
130 qword_add(bpp, blen, key->hostname);
131 (*bpp)[-1] = '\n';
132}
133
134static int nfs_dns_upcall(struct cache_detail *cd,
135 struct cache_head *ch)
136{
137 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
138 int ret;
139
140 ret = nfs_cache_upcall(cd, key->hostname);
141 if (ret)
142 ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request);
143 return ret;
144}
145
146static int nfs_dns_match(struct cache_head *ca,
147 struct cache_head *cb)
148{
149 struct nfs_dns_ent *a;
150 struct nfs_dns_ent *b;
151
152 a = container_of(ca, struct nfs_dns_ent, h);
153 b = container_of(cb, struct nfs_dns_ent, h);
154
155 if (a->namelen == 0 || a->namelen != b->namelen)
156 return 0;
157 return memcmp(a->hostname, b->hostname, a->namelen) == 0;
158}
159
160static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
161 struct cache_head *h)
162{
163 struct nfs_dns_ent *item;
164 long ttl;
165
166 if (h == NULL) {
167 seq_puts(m, "# ip address hostname ttl\n");
168 return 0;
169 }
170 item = container_of(h, struct nfs_dns_ent, h);
171 ttl = item->h.expiry_time - seconds_since_boot();
172 if (ttl < 0)
173 ttl = 0;
174
175 if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
176 char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
177
178 rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
179 seq_printf(m, "%15s ", buf);
180 } else
181 seq_puts(m, "<none> ");
182 seq_printf(m, "%15s %ld\n", item->hostname, ttl);
183 return 0;
184}
185
186static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
187 struct nfs_dns_ent *key)
188{
189 struct cache_head *ch;
190
191 ch = sunrpc_cache_lookup(cd,
192 &key->h,
193 nfs_dns_hash(key));
194 if (!ch)
195 return NULL;
196 return container_of(ch, struct nfs_dns_ent, h);
197}
198
199static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
200 struct nfs_dns_ent *new,
201 struct nfs_dns_ent *key)
202{
203 struct cache_head *ch;
204
205 ch = sunrpc_cache_update(cd,
206 &new->h, &key->h,
207 nfs_dns_hash(key));
208 if (!ch)
209 return NULL;
210 return container_of(ch, struct nfs_dns_ent, h);
211}
212
213static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
214{
215 char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
216 struct nfs_dns_ent key, *item;
217 unsigned long ttl;
218 ssize_t len;
219 int ret = -EINVAL;
220
221 if (buf[buflen-1] != '\n')
222 goto out;
223 buf[buflen-1] = '\0';
224
225 len = qword_get(&buf, buf1, sizeof(buf1));
226 if (len <= 0)
227 goto out;
228 key.addrlen = rpc_pton(cd->net, buf1, len,
229 (struct sockaddr *)&key.addr,
230 sizeof(key.addr));
231
232 len = qword_get(&buf, buf1, sizeof(buf1));
233 if (len <= 0)
234 goto out;
235
236 key.hostname = buf1;
237 key.namelen = len;
238 memset(&key.h, 0, sizeof(key.h));
239
240 ttl = get_expiry(&buf);
241 if (ttl == 0)
242 goto out;
243 key.h.expiry_time = ttl + seconds_since_boot();
244
245 ret = -ENOMEM;
246 item = nfs_dns_lookup(cd, &key);
247 if (item == NULL)
248 goto out;
249
250 if (key.addrlen == 0)
251 set_bit(CACHE_NEGATIVE, &key.h.flags);
252
253 item = nfs_dns_update(cd, &key, item);
254 if (item == NULL)
255 goto out;
256
257 ret = 0;
258 cache_put(&item->h, cd);
259out:
260 return ret;
261}
262
263static int do_cache_lookup(struct cache_detail *cd,
264 struct nfs_dns_ent *key,
265 struct nfs_dns_ent **item,
266 struct nfs_cache_defer_req *dreq)
267{
268 int ret = -ENOMEM;
269
270 *item = nfs_dns_lookup(cd, key);
271 if (*item) {
272 ret = cache_check(cd, &(*item)->h, &dreq->req);
273 if (ret)
274 *item = NULL;
275 }
276 return ret;
277}
278
279static int do_cache_lookup_nowait(struct cache_detail *cd,
280 struct nfs_dns_ent *key,
281 struct nfs_dns_ent **item)
282{
283 int ret = -ENOMEM;
284
285 *item = nfs_dns_lookup(cd, key);
286 if (!*item)
287 goto out_err;
288 ret = -ETIMEDOUT;
289 if (!test_bit(CACHE_VALID, &(*item)->h.flags)
290 || (*item)->h.expiry_time < seconds_since_boot()
291 || cd->flush_time > (*item)->h.last_refresh)
292 goto out_put;
293 ret = -ENOENT;
294 if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
295 goto out_put;
296 return 0;
297out_put:
298 cache_put(&(*item)->h, cd);
299out_err:
300 *item = NULL;
301 return ret;
302}
303
304static int do_cache_lookup_wait(struct cache_detail *cd,
305 struct nfs_dns_ent *key,
306 struct nfs_dns_ent **item)
307{
308 struct nfs_cache_defer_req *dreq;
309 int ret = -ENOMEM;
310
311 dreq = nfs_cache_defer_req_alloc();
312 if (!dreq)
313 goto out;
314 ret = do_cache_lookup(cd, key, item, dreq);
315 if (ret == -EAGAIN) {
316 ret = nfs_cache_wait_for_upcall(dreq);
317 if (!ret)
318 ret = do_cache_lookup_nowait(cd, key, item);
319 }
320 nfs_cache_defer_req_put(dreq);
321out:
322 return ret;
323}
324
325ssize_t nfs_dns_resolve_name(struct net *net, char *name,
326 size_t namelen, struct sockaddr *sa, size_t salen)
327{
328 struct nfs_dns_ent key = {
329 .hostname = name,
330 .namelen = namelen,
331 };
332 struct nfs_dns_ent *item = NULL;
333 ssize_t ret;
334 struct nfs_net *nn = net_generic(net, nfs_net_id);
335
336 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
337 if (ret == 0) {
338 if (salen >= item->addrlen) {
339 memcpy(sa, &item->addr, item->addrlen);
340 ret = item->addrlen;
341 } else
342 ret = -EOVERFLOW;
343 cache_put(&item->h, nn->nfs_dns_resolve);
344 } else if (ret == -ENOENT)
345 ret = -ESRCH;
346 return ret;
347}
348
349int nfs_dns_resolver_cache_init(struct net *net)
350{
351 int err = -ENOMEM;
352 struct nfs_net *nn = net_generic(net, nfs_net_id);
353 struct cache_detail *cd;
354 struct cache_head **tbl;
355
356 cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL);
357 if (cd == NULL)
358 goto err_cd;
359
360 tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *),
361 GFP_KERNEL);
362 if (tbl == NULL)
363 goto err_tbl;
364
365 cd->owner = THIS_MODULE,
366 cd->hash_size = NFS_DNS_HASHTBL_SIZE,
367 cd->hash_table = tbl,
368 cd->name = "dns_resolve",
369 cd->cache_put = nfs_dns_ent_put,
370 cd->cache_upcall = nfs_dns_upcall,
371 cd->cache_parse = nfs_dns_parse,
372 cd->cache_show = nfs_dns_show,
373 cd->match = nfs_dns_match,
374 cd->init = nfs_dns_ent_init,
375 cd->update = nfs_dns_ent_update,
376 cd->alloc = nfs_dns_ent_alloc,
377
378 nfs_cache_init(cd);
379 err = nfs_cache_register_net(net, cd);
380 if (err)
381 goto err_reg;
382 nn->nfs_dns_resolve = cd;
383 return 0;
384
385err_reg:
386 nfs_cache_destroy(cd);
387 kfree(cd->hash_table);
388err_tbl:
389 kfree(cd);
390err_cd:
391 return err;
392}
393
394void nfs_dns_resolver_cache_destroy(struct net *net)
395{
396 struct nfs_net *nn = net_generic(net, nfs_net_id);
397 struct cache_detail *cd = nn->nfs_dns_resolve;
398
399 nfs_cache_unregister_net(net, cd);
400 nfs_cache_destroy(cd);
401 kfree(cd->hash_table);
402 kfree(cd);
403}
404
405static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
406 void *ptr)
407{
408 struct super_block *sb = ptr;
409 struct net *net = sb->s_fs_info;
410 struct nfs_net *nn = net_generic(net, nfs_net_id);
411 struct cache_detail *cd = nn->nfs_dns_resolve;
412 int ret = 0;
413
414 if (cd == NULL)
415 return 0;
416
417 if (!try_module_get(THIS_MODULE))
418 return 0;
419
420 switch (event) {
421 case RPC_PIPEFS_MOUNT:
422 ret = nfs_cache_register_sb(sb, cd);
423 break;
424 case RPC_PIPEFS_UMOUNT:
425 nfs_cache_unregister_sb(sb, cd);
426 break;
427 default:
428 ret = -ENOTSUPP;
429 break;
430 }
431 module_put(THIS_MODULE);
432 return ret;
433}
434
435static struct notifier_block nfs_dns_resolver_block = {
436 .notifier_call = rpc_pipefs_event,
437};
438
439int nfs_dns_resolver_init(void)
440{
441 return rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
442}
443
444void nfs_dns_resolver_destroy(void)
445{
446 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
447}
448#endif