Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e571cbf1 TM |
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 | ||
c2e8139c BS |
10 | #ifdef CONFIG_NFS_USE_KERNEL_DNS |
11 | ||
89d77c8f | 12 | #include <linux/module.h> |
c2e8139c | 13 | #include <linux/sunrpc/clnt.h> |
5976687a | 14 | #include <linux/sunrpc/addr.h> |
c2e8139c | 15 | #include <linux/dns_resolver.h> |
17280175 | 16 | #include "dns_resolve.h" |
c2e8139c | 17 | |
1b340d01 | 18 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen, |
c2e8139c BS |
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(NULL, name, namelen, NULL, &ip_addr, NULL); | |
26 | if (ip_len > 0) | |
bc224f53 | 27 | ret = rpc_pton(net, ip_addr, ip_len, sa, salen); |
c2e8139c BS |
28 | else |
29 | ret = -ESRCH; | |
30 | kfree(ip_addr); | |
31 | return ret; | |
32 | } | |
33 | ||
34 | #else | |
35 | ||
89d77c8f | 36 | #include <linux/module.h> |
e571cbf1 TM |
37 | #include <linux/hash.h> |
38 | #include <linux/string.h> | |
39 | #include <linux/kmod.h> | |
5a0e3ad6 | 40 | #include <linux/slab.h> |
e571cbf1 TM |
41 | #include <linux/module.h> |
42 | #include <linux/socket.h> | |
43 | #include <linux/seq_file.h> | |
44 | #include <linux/inet.h> | |
45 | #include <linux/sunrpc/clnt.h> | |
5976687a | 46 | #include <linux/sunrpc/addr.h> |
e571cbf1 TM |
47 | #include <linux/sunrpc/cache.h> |
48 | #include <linux/sunrpc/svcauth.h> | |
9df69c81 | 49 | #include <linux/sunrpc/rpc_pipe_fs.h> |
694e096f | 50 | #include <linux/nfs_fs.h> |
e571cbf1 | 51 | |
694e096f | 52 | #include "nfs4_fs.h" |
e571cbf1 TM |
53 | #include "dns_resolve.h" |
54 | #include "cache_lib.h" | |
1b340d01 | 55 | #include "netns.h" |
e571cbf1 TM |
56 | |
57 | #define NFS_DNS_HASHBITS 4 | |
58 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) | |
59 | ||
e571cbf1 TM |
60 | struct nfs_dns_ent { |
61 | struct cache_head h; | |
62 | ||
63 | char *hostname; | |
64 | size_t namelen; | |
65 | ||
66 | struct sockaddr_storage addr; | |
67 | size_t addrlen; | |
68 | }; | |
69 | ||
70 | ||
ebed9203 TM |
71 | static 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 | ||
e571cbf1 TM |
84 | static 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 = kstrndup(key->hostname, key->namelen, GFP_KERNEL); | |
95 | if (new->hostname) { | |
96 | new->namelen = key->namelen; | |
ebed9203 | 97 | nfs_dns_ent_update(cnew, ckey); |
e571cbf1 TM |
98 | } else { |
99 | new->namelen = 0; | |
100 | new->addrlen = 0; | |
101 | } | |
102 | } | |
103 | ||
104 | static void nfs_dns_ent_put(struct kref *ref) | |
105 | { | |
106 | struct nfs_dns_ent *item; | |
107 | ||
108 | item = container_of(ref, struct nfs_dns_ent, h.ref); | |
109 | kfree(item->hostname); | |
110 | kfree(item); | |
111 | } | |
112 | ||
113 | static struct cache_head *nfs_dns_ent_alloc(void) | |
114 | { | |
115 | struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL); | |
116 | ||
117 | if (item != NULL) { | |
118 | item->hostname = NULL; | |
119 | item->namelen = 0; | |
120 | item->addrlen = 0; | |
121 | return &item->h; | |
122 | } | |
123 | return NULL; | |
124 | }; | |
125 | ||
126 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) | |
127 | { | |
128 | return hash_str(key->hostname, NFS_DNS_HASHBITS); | |
129 | } | |
130 | ||
131 | static void nfs_dns_request(struct cache_detail *cd, | |
132 | struct cache_head *ch, | |
133 | char **bpp, int *blen) | |
134 | { | |
135 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
136 | ||
137 | qword_add(bpp, blen, key->hostname); | |
138 | (*bpp)[-1] = '\n'; | |
139 | } | |
140 | ||
141 | static int nfs_dns_upcall(struct cache_detail *cd, | |
142 | struct cache_head *ch) | |
143 | { | |
144 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
145 | int ret; | |
146 | ||
147 | ret = nfs_cache_upcall(cd, key->hostname); | |
148 | if (ret) | |
21cd1254 | 149 | ret = sunrpc_cache_pipe_upcall(cd, ch); |
e571cbf1 TM |
150 | return ret; |
151 | } | |
152 | ||
153 | static int nfs_dns_match(struct cache_head *ca, | |
154 | struct cache_head *cb) | |
155 | { | |
156 | struct nfs_dns_ent *a; | |
157 | struct nfs_dns_ent *b; | |
158 | ||
159 | a = container_of(ca, struct nfs_dns_ent, h); | |
160 | b = container_of(cb, struct nfs_dns_ent, h); | |
161 | ||
162 | if (a->namelen == 0 || a->namelen != b->namelen) | |
163 | return 0; | |
164 | return memcmp(a->hostname, b->hostname, a->namelen) == 0; | |
165 | } | |
166 | ||
167 | static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd, | |
168 | struct cache_head *h) | |
169 | { | |
170 | struct nfs_dns_ent *item; | |
171 | long ttl; | |
172 | ||
173 | if (h == NULL) { | |
174 | seq_puts(m, "# ip address hostname ttl\n"); | |
175 | return 0; | |
176 | } | |
177 | item = container_of(h, struct nfs_dns_ent, h); | |
c5b29f88 | 178 | ttl = item->h.expiry_time - seconds_since_boot(); |
e571cbf1 TM |
179 | if (ttl < 0) |
180 | ttl = 0; | |
181 | ||
182 | if (!test_bit(CACHE_NEGATIVE, &h->flags)) { | |
183 | char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1]; | |
184 | ||
185 | rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf)); | |
186 | seq_printf(m, "%15s ", buf); | |
187 | } else | |
188 | seq_puts(m, "<none> "); | |
189 | seq_printf(m, "%15s %ld\n", item->hostname, ttl); | |
190 | return 0; | |
191 | } | |
192 | ||
0a6566ec | 193 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
e571cbf1 TM |
194 | struct nfs_dns_ent *key) |
195 | { | |
196 | struct cache_head *ch; | |
197 | ||
198 | ch = sunrpc_cache_lookup(cd, | |
199 | &key->h, | |
200 | nfs_dns_hash(key)); | |
201 | if (!ch) | |
202 | return NULL; | |
203 | return container_of(ch, struct nfs_dns_ent, h); | |
204 | } | |
205 | ||
0a6566ec | 206 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
e571cbf1 TM |
207 | struct nfs_dns_ent *new, |
208 | struct nfs_dns_ent *key) | |
209 | { | |
210 | struct cache_head *ch; | |
211 | ||
212 | ch = sunrpc_cache_update(cd, | |
213 | &new->h, &key->h, | |
214 | nfs_dns_hash(key)); | |
215 | if (!ch) | |
216 | return NULL; | |
217 | return container_of(ch, struct nfs_dns_ent, h); | |
218 | } | |
219 | ||
220 | static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) | |
221 | { | |
222 | char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; | |
223 | struct nfs_dns_ent key, *item; | |
8d96b106 | 224 | unsigned int ttl; |
e571cbf1 TM |
225 | ssize_t len; |
226 | int ret = -EINVAL; | |
227 | ||
228 | if (buf[buflen-1] != '\n') | |
229 | goto out; | |
230 | buf[buflen-1] = '\0'; | |
231 | ||
232 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
233 | if (len <= 0) | |
234 | goto out; | |
599ec129 | 235 | key.addrlen = rpc_pton(cd->net, buf1, len, |
e571cbf1 TM |
236 | (struct sockaddr *)&key.addr, |
237 | sizeof(key.addr)); | |
238 | ||
239 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
240 | if (len <= 0) | |
241 | goto out; | |
242 | ||
243 | key.hostname = buf1; | |
244 | key.namelen = len; | |
245 | memset(&key.h, 0, sizeof(key.h)); | |
246 | ||
8d96b106 N |
247 | if (get_uint(&buf, &ttl) < 0) |
248 | goto out; | |
e571cbf1 TM |
249 | if (ttl == 0) |
250 | goto out; | |
c5b29f88 | 251 | key.h.expiry_time = ttl + seconds_since_boot(); |
e571cbf1 TM |
252 | |
253 | ret = -ENOMEM; | |
254 | item = nfs_dns_lookup(cd, &key); | |
255 | if (item == NULL) | |
256 | goto out; | |
257 | ||
258 | if (key.addrlen == 0) | |
259 | set_bit(CACHE_NEGATIVE, &key.h.flags); | |
260 | ||
261 | item = nfs_dns_update(cd, &key, item); | |
262 | if (item == NULL) | |
263 | goto out; | |
264 | ||
265 | ret = 0; | |
266 | cache_put(&item->h, cd); | |
267 | out: | |
268 | return ret; | |
269 | } | |
270 | ||
e571cbf1 TM |
271 | static int do_cache_lookup(struct cache_detail *cd, |
272 | struct nfs_dns_ent *key, | |
273 | struct nfs_dns_ent **item, | |
274 | struct nfs_cache_defer_req *dreq) | |
275 | { | |
276 | int ret = -ENOMEM; | |
277 | ||
278 | *item = nfs_dns_lookup(cd, key); | |
279 | if (*item) { | |
280 | ret = cache_check(cd, &(*item)->h, &dreq->req); | |
281 | if (ret) | |
282 | *item = NULL; | |
283 | } | |
284 | return ret; | |
285 | } | |
286 | ||
287 | static int do_cache_lookup_nowait(struct cache_detail *cd, | |
288 | struct nfs_dns_ent *key, | |
289 | struct nfs_dns_ent **item) | |
290 | { | |
291 | int ret = -ENOMEM; | |
292 | ||
293 | *item = nfs_dns_lookup(cd, key); | |
294 | if (!*item) | |
295 | goto out_err; | |
296 | ret = -ETIMEDOUT; | |
297 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) | |
c5b29f88 | 298 | || (*item)->h.expiry_time < seconds_since_boot() |
e571cbf1 TM |
299 | || cd->flush_time > (*item)->h.last_refresh) |
300 | goto out_put; | |
301 | ret = -ENOENT; | |
302 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) | |
303 | goto out_put; | |
304 | return 0; | |
305 | out_put: | |
306 | cache_put(&(*item)->h, cd); | |
307 | out_err: | |
308 | *item = NULL; | |
309 | return ret; | |
310 | } | |
311 | ||
312 | static int do_cache_lookup_wait(struct cache_detail *cd, | |
313 | struct nfs_dns_ent *key, | |
314 | struct nfs_dns_ent **item) | |
315 | { | |
316 | struct nfs_cache_defer_req *dreq; | |
317 | int ret = -ENOMEM; | |
318 | ||
319 | dreq = nfs_cache_defer_req_alloc(); | |
320 | if (!dreq) | |
321 | goto out; | |
322 | ret = do_cache_lookup(cd, key, item, dreq); | |
323 | if (ret == -EAGAIN) { | |
324 | ret = nfs_cache_wait_for_upcall(dreq); | |
325 | if (!ret) | |
326 | ret = do_cache_lookup_nowait(cd, key, item); | |
327 | } | |
328 | nfs_cache_defer_req_put(dreq); | |
329 | out: | |
330 | return ret; | |
331 | } | |
332 | ||
1b340d01 SK |
333 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, |
334 | size_t namelen, struct sockaddr *sa, size_t salen) | |
e571cbf1 TM |
335 | { |
336 | struct nfs_dns_ent key = { | |
337 | .hostname = name, | |
338 | .namelen = namelen, | |
339 | }; | |
340 | struct nfs_dns_ent *item = NULL; | |
341 | ssize_t ret; | |
1b340d01 | 342 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
e571cbf1 | 343 | |
1b340d01 | 344 | ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item); |
e571cbf1 TM |
345 | if (ret == 0) { |
346 | if (salen >= item->addrlen) { | |
347 | memcpy(sa, &item->addr, item->addrlen); | |
348 | ret = item->addrlen; | |
349 | } else | |
350 | ret = -EOVERFLOW; | |
1b340d01 | 351 | cache_put(&item->h, nn->nfs_dns_resolve); |
e571cbf1 TM |
352 | } else if (ret == -ENOENT) |
353 | ret = -ESRCH; | |
354 | return ret; | |
355 | } | |
356 | ||
483479c2 SK |
357 | static struct cache_detail nfs_dns_resolve_template = { |
358 | .owner = THIS_MODULE, | |
359 | .hash_size = NFS_DNS_HASHTBL_SIZE, | |
360 | .name = "dns_resolve", | |
361 | .cache_put = nfs_dns_ent_put, | |
362 | .cache_upcall = nfs_dns_upcall, | |
73fb847a | 363 | .cache_request = nfs_dns_request, |
483479c2 SK |
364 | .cache_parse = nfs_dns_parse, |
365 | .cache_show = nfs_dns_show, | |
366 | .match = nfs_dns_match, | |
367 | .init = nfs_dns_ent_init, | |
368 | .update = nfs_dns_ent_update, | |
369 | .alloc = nfs_dns_ent_alloc, | |
370 | }; | |
371 | ||
372 | ||
1b340d01 | 373 | int nfs_dns_resolver_cache_init(struct net *net) |
e571cbf1 | 374 | { |
483479c2 | 375 | int err; |
1b340d01 | 376 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
1b340d01 | 377 | |
483479c2 SK |
378 | nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net); |
379 | if (IS_ERR(nn->nfs_dns_resolve)) | |
380 | return PTR_ERR(nn->nfs_dns_resolve); | |
381 | ||
483479c2 | 382 | err = nfs_cache_register_net(net, nn->nfs_dns_resolve); |
1b340d01 SK |
383 | if (err) |
384 | goto err_reg; | |
1b340d01 | 385 | return 0; |
9222b955 | 386 | |
1b340d01 | 387 | err_reg: |
483479c2 | 388 | cache_destroy_net(nn->nfs_dns_resolve, net); |
1b340d01 SK |
389 | return err; |
390 | } | |
391 | ||
392 | void nfs_dns_resolver_cache_destroy(struct net *net) | |
393 | { | |
394 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
1b340d01 | 395 | |
462b8f6b | 396 | nfs_cache_unregister_net(net, nn->nfs_dns_resolve); |
483479c2 | 397 | cache_destroy_net(nn->nfs_dns_resolve, net); |
1b340d01 SK |
398 | } |
399 | ||
c8d74d9b TM |
400 | static int nfs4_dns_net_init(struct net *net) |
401 | { | |
402 | return nfs_dns_resolver_cache_init(net); | |
403 | } | |
404 | ||
405 | static void nfs4_dns_net_exit(struct net *net) | |
406 | { | |
407 | nfs_dns_resolver_cache_destroy(net); | |
408 | } | |
409 | ||
410 | static struct pernet_operations nfs4_dns_resolver_ops = { | |
411 | .init = nfs4_dns_net_init, | |
412 | .exit = nfs4_dns_net_exit, | |
413 | }; | |
414 | ||
9df69c81 SK |
415 | static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event, |
416 | void *ptr) | |
417 | { | |
418 | struct super_block *sb = ptr; | |
419 | struct net *net = sb->s_fs_info; | |
420 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
421 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
422 | int ret = 0; | |
423 | ||
424 | if (cd == NULL) | |
425 | return 0; | |
426 | ||
427 | if (!try_module_get(THIS_MODULE)) | |
428 | return 0; | |
429 | ||
430 | switch (event) { | |
431 | case RPC_PIPEFS_MOUNT: | |
432 | ret = nfs_cache_register_sb(sb, cd); | |
433 | break; | |
434 | case RPC_PIPEFS_UMOUNT: | |
435 | nfs_cache_unregister_sb(sb, cd); | |
436 | break; | |
437 | default: | |
438 | ret = -ENOTSUPP; | |
439 | break; | |
440 | } | |
441 | module_put(THIS_MODULE); | |
442 | return ret; | |
443 | } | |
444 | ||
445 | static struct notifier_block nfs_dns_resolver_block = { | |
446 | .notifier_call = rpc_pipefs_event, | |
447 | }; | |
448 | ||
1b340d01 SK |
449 | int nfs_dns_resolver_init(void) |
450 | { | |
c8d74d9b TM |
451 | int err; |
452 | ||
453 | err = register_pernet_subsys(&nfs4_dns_resolver_ops); | |
454 | if (err < 0) | |
455 | goto out; | |
456 | err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block); | |
457 | if (err < 0) | |
458 | goto out1; | |
459 | return 0; | |
460 | out1: | |
461 | unregister_pernet_subsys(&nfs4_dns_resolver_ops); | |
462 | out: | |
463 | return err; | |
e571cbf1 TM |
464 | } |
465 | ||
466 | void nfs_dns_resolver_destroy(void) | |
467 | { | |
9df69c81 | 468 | rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block); |
c8d74d9b | 469 | unregister_pernet_subsys(&nfs4_dns_resolver_ops); |
e571cbf1 | 470 | } |
c2e8139c | 471 | #endif |