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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/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
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 *sa, size_t salen)
20{
21 ssize_t ret;
22 char *ip_addr = NULL;
23 int ip_len;
24
25 ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
26 false);
27 if (ip_len > 0)
28 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
29 else
30 ret = -ESRCH;
31 kfree(ip_addr);
32 return ret;
33}
34
35#else
36
37#include <linux/module.h>
38#include <linux/hash.h>
39#include <linux/string.h>
40#include <linux/kmod.h>
41#include <linux/slab.h>
42#include <linux/module.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 = kstrndup(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 int ret;
156
157 ret = nfs_cache_upcall(cd, key->hostname);
158 if (ret)
159 ret = sunrpc_cache_pipe_upcall(cd, ch);
160 return ret;
161}
162
163static int nfs_dns_match(struct cache_head *ca,
164 struct cache_head *cb)
165{
166 struct nfs_dns_ent *a;
167 struct nfs_dns_ent *b;
168
169 a = container_of(ca, struct nfs_dns_ent, h);
170 b = container_of(cb, struct nfs_dns_ent, h);
171
172 if (a->namelen == 0 || a->namelen != b->namelen)
173 return 0;
174 return memcmp(a->hostname, b->hostname, a->namelen) == 0;
175}
176
177static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
178 struct cache_head *h)
179{
180 struct nfs_dns_ent *item;
181 long ttl;
182
183 if (h == NULL) {
184 seq_puts(m, "# ip address hostname ttl\n");
185 return 0;
186 }
187 item = container_of(h, struct nfs_dns_ent, h);
188 ttl = item->h.expiry_time - seconds_since_boot();
189 if (ttl < 0)
190 ttl = 0;
191
192 if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
193 char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
194
195 rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
196 seq_printf(m, "%15s ", buf);
197 } else
198 seq_puts(m, "<none> ");
199 seq_printf(m, "%15s %ld\n", item->hostname, ttl);
200 return 0;
201}
202
203static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
204 struct nfs_dns_ent *key)
205{
206 struct cache_head *ch;
207
208 ch = sunrpc_cache_lookup_rcu(cd,
209 &key->h,
210 nfs_dns_hash(key));
211 if (!ch)
212 return NULL;
213 return container_of(ch, struct nfs_dns_ent, h);
214}
215
216static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
217 struct nfs_dns_ent *new,
218 struct nfs_dns_ent *key)
219{
220 struct cache_head *ch;
221
222 ch = sunrpc_cache_update(cd,
223 &new->h, &key->h,
224 nfs_dns_hash(key));
225 if (!ch)
226 return NULL;
227 return container_of(ch, struct nfs_dns_ent, h);
228}
229
230static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
231{
232 char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
233 struct nfs_dns_ent key, *item;
234 unsigned int ttl;
235 ssize_t len;
236 int ret = -EINVAL;
237
238 if (buf[buflen-1] != '\n')
239 goto out;
240 buf[buflen-1] = '\0';
241
242 len = qword_get(&buf, buf1, sizeof(buf1));
243 if (len <= 0)
244 goto out;
245 key.addrlen = rpc_pton(cd->net, buf1, len,
246 (struct sockaddr *)&key.addr,
247 sizeof(key.addr));
248
249 len = qword_get(&buf, buf1, sizeof(buf1));
250 if (len <= 0)
251 goto out;
252
253 key.hostname = buf1;
254 key.namelen = len;
255 memset(&key.h, 0, sizeof(key.h));
256
257 if (get_uint(&buf, &ttl) < 0)
258 goto out;
259 if (ttl == 0)
260 goto out;
261 key.h.expiry_time = ttl + seconds_since_boot();
262
263 ret = -ENOMEM;
264 item = nfs_dns_lookup(cd, &key);
265 if (item == NULL)
266 goto out;
267
268 if (key.addrlen == 0)
269 set_bit(CACHE_NEGATIVE, &key.h.flags);
270
271 item = nfs_dns_update(cd, &key, item);
272 if (item == NULL)
273 goto out;
274
275 ret = 0;
276 cache_put(&item->h, cd);
277out:
278 return ret;
279}
280
281static int do_cache_lookup(struct cache_detail *cd,
282 struct nfs_dns_ent *key,
283 struct nfs_dns_ent **item,
284 struct nfs_cache_defer_req *dreq)
285{
286 int ret = -ENOMEM;
287
288 *item = nfs_dns_lookup(cd, key);
289 if (*item) {
290 ret = cache_check(cd, &(*item)->h, &dreq->req);
291 if (ret)
292 *item = NULL;
293 }
294 return ret;
295}
296
297static int do_cache_lookup_nowait(struct cache_detail *cd,
298 struct nfs_dns_ent *key,
299 struct nfs_dns_ent **item)
300{
301 int ret = -ENOMEM;
302
303 *item = nfs_dns_lookup(cd, key);
304 if (!*item)
305 goto out_err;
306 ret = -ETIMEDOUT;
307 if (!test_bit(CACHE_VALID, &(*item)->h.flags)
308 || (*item)->h.expiry_time < seconds_since_boot()
309 || cd->flush_time > (*item)->h.last_refresh)
310 goto out_put;
311 ret = -ENOENT;
312 if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
313 goto out_put;
314 return 0;
315out_put:
316 cache_put(&(*item)->h, cd);
317out_err:
318 *item = NULL;
319 return ret;
320}
321
322static int do_cache_lookup_wait(struct cache_detail *cd,
323 struct nfs_dns_ent *key,
324 struct nfs_dns_ent **item)
325{
326 struct nfs_cache_defer_req *dreq;
327 int ret = -ENOMEM;
328
329 dreq = nfs_cache_defer_req_alloc();
330 if (!dreq)
331 goto out;
332 ret = do_cache_lookup(cd, key, item, dreq);
333 if (ret == -EAGAIN) {
334 ret = nfs_cache_wait_for_upcall(dreq);
335 if (!ret)
336 ret = do_cache_lookup_nowait(cd, key, item);
337 }
338 nfs_cache_defer_req_put(dreq);
339out:
340 return ret;
341}
342
343ssize_t nfs_dns_resolve_name(struct net *net, char *name,
344 size_t namelen, struct sockaddr *sa, size_t salen)
345{
346 struct nfs_dns_ent key = {
347 .hostname = name,
348 .namelen = namelen,
349 };
350 struct nfs_dns_ent *item = NULL;
351 ssize_t ret;
352 struct nfs_net *nn = net_generic(net, nfs_net_id);
353
354 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
355 if (ret == 0) {
356 if (salen >= item->addrlen) {
357 memcpy(sa, &item->addr, item->addrlen);
358 ret = item->addrlen;
359 } else
360 ret = -EOVERFLOW;
361 cache_put(&item->h, nn->nfs_dns_resolve);
362 } else if (ret == -ENOENT)
363 ret = -ESRCH;
364 return ret;
365}
366
367static struct cache_detail nfs_dns_resolve_template = {
368 .owner = THIS_MODULE,
369 .hash_size = NFS_DNS_HASHTBL_SIZE,
370 .name = "dns_resolve",
371 .cache_put = nfs_dns_ent_put,
372 .cache_upcall = nfs_dns_upcall,
373 .cache_request = nfs_dns_request,
374 .cache_parse = nfs_dns_parse,
375 .cache_show = nfs_dns_show,
376 .match = nfs_dns_match,
377 .init = nfs_dns_ent_init,
378 .update = nfs_dns_ent_update,
379 .alloc = nfs_dns_ent_alloc,
380};
381
382
383int nfs_dns_resolver_cache_init(struct net *net)
384{
385 int err;
386 struct nfs_net *nn = net_generic(net, nfs_net_id);
387
388 nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
389 if (IS_ERR(nn->nfs_dns_resolve))
390 return PTR_ERR(nn->nfs_dns_resolve);
391
392 err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
393 if (err)
394 goto err_reg;
395 return 0;
396
397err_reg:
398 cache_destroy_net(nn->nfs_dns_resolve, net);
399 return err;
400}
401
402void nfs_dns_resolver_cache_destroy(struct net *net)
403{
404 struct nfs_net *nn = net_generic(net, nfs_net_id);
405
406 nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
407 cache_destroy_net(nn->nfs_dns_resolve, net);
408}
409
410static int nfs4_dns_net_init(struct net *net)
411{
412 return nfs_dns_resolver_cache_init(net);
413}
414
415static void nfs4_dns_net_exit(struct net *net)
416{
417 nfs_dns_resolver_cache_destroy(net);
418}
419
420static struct pernet_operations nfs4_dns_resolver_ops = {
421 .init = nfs4_dns_net_init,
422 .exit = nfs4_dns_net_exit,
423};
424
425static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
426 void *ptr)
427{
428 struct super_block *sb = ptr;
429 struct net *net = sb->s_fs_info;
430 struct nfs_net *nn = net_generic(net, nfs_net_id);
431 struct cache_detail *cd = nn->nfs_dns_resolve;
432 int ret = 0;
433
434 if (cd == NULL)
435 return 0;
436
437 if (!try_module_get(THIS_MODULE))
438 return 0;
439
440 switch (event) {
441 case RPC_PIPEFS_MOUNT:
442 ret = nfs_cache_register_sb(sb, cd);
443 break;
444 case RPC_PIPEFS_UMOUNT:
445 nfs_cache_unregister_sb(sb, cd);
446 break;
447 default:
448 ret = -ENOTSUPP;
449 break;
450 }
451 module_put(THIS_MODULE);
452 return ret;
453}
454
455static struct notifier_block nfs_dns_resolver_block = {
456 .notifier_call = rpc_pipefs_event,
457};
458
459int nfs_dns_resolver_init(void)
460{
461 int err;
462
463 err = register_pernet_subsys(&nfs4_dns_resolver_ops);
464 if (err < 0)
465 goto out;
466 err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
467 if (err < 0)
468 goto out1;
469 return 0;
470out1:
471 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
472out:
473 return err;
474}
475
476void nfs_dns_resolver_destroy(void)
477{
478 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
479 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
480}
481#endif