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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
482
