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e571cbf1 TM |
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 | ||
c2e8139c BS |
9 | #ifdef CONFIG_NFS_USE_KERNEL_DNS |
10 | ||
89d77c8f | 11 | #include <linux/module.h> |
c2e8139c | 12 | #include <linux/sunrpc/clnt.h> |
5976687a | 13 | #include <linux/sunrpc/addr.h> |
c2e8139c | 14 | #include <linux/dns_resolver.h> |
17280175 | 15 | #include "dns_resolve.h" |
c2e8139c | 16 | |
1b340d01 | 17 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen, |
c2e8139c BS |
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) | |
bc224f53 | 26 | ret = rpc_pton(net, ip_addr, ip_len, sa, salen); |
c2e8139c BS |
27 | else |
28 | ret = -ESRCH; | |
29 | kfree(ip_addr); | |
30 | return ret; | |
31 | } | |
32 | ||
33 | #else | |
34 | ||
89d77c8f | 35 | #include <linux/module.h> |
e571cbf1 TM |
36 | #include <linux/hash.h> |
37 | #include <linux/string.h> | |
38 | #include <linux/kmod.h> | |
5a0e3ad6 | 39 | #include <linux/slab.h> |
e571cbf1 TM |
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> | |
5976687a | 45 | #include <linux/sunrpc/addr.h> |
e571cbf1 TM |
46 | #include <linux/sunrpc/cache.h> |
47 | #include <linux/sunrpc/svcauth.h> | |
9df69c81 | 48 | #include <linux/sunrpc/rpc_pipe_fs.h> |
e571cbf1 TM |
49 | |
50 | #include "dns_resolve.h" | |
51 | #include "cache_lib.h" | |
1b340d01 | 52 | #include "netns.h" |
e571cbf1 TM |
53 | |
54 | #define NFS_DNS_HASHBITS 4 | |
55 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) | |
56 | ||
e571cbf1 TM |
57 | struct nfs_dns_ent { |
58 | struct cache_head h; | |
59 | ||
60 | char *hostname; | |
61 | size_t namelen; | |
62 | ||
63 | struct sockaddr_storage addr; | |
64 | size_t addrlen; | |
65 | }; | |
66 | ||
67 | ||
ebed9203 TM |
68 | static void nfs_dns_ent_update(struct cache_head *cnew, |
69 | struct cache_head *ckey) | |
70 | { | |
71 | struct nfs_dns_ent *new; | |
72 | struct nfs_dns_ent *key; | |
73 | ||
74 | new = container_of(cnew, struct nfs_dns_ent, h); | |
75 | key = container_of(ckey, struct nfs_dns_ent, h); | |
76 | ||
77 | memcpy(&new->addr, &key->addr, key->addrlen); | |
78 | new->addrlen = key->addrlen; | |
79 | } | |
80 | ||
e571cbf1 TM |
81 | static void nfs_dns_ent_init(struct cache_head *cnew, |
82 | struct cache_head *ckey) | |
83 | { | |
84 | struct nfs_dns_ent *new; | |
85 | struct nfs_dns_ent *key; | |
86 | ||
87 | new = container_of(cnew, struct nfs_dns_ent, h); | |
88 | key = container_of(ckey, struct nfs_dns_ent, h); | |
89 | ||
90 | kfree(new->hostname); | |
91 | new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL); | |
92 | if (new->hostname) { | |
93 | new->namelen = key->namelen; | |
ebed9203 | 94 | nfs_dns_ent_update(cnew, ckey); |
e571cbf1 TM |
95 | } else { |
96 | new->namelen = 0; | |
97 | new->addrlen = 0; | |
98 | } | |
99 | } | |
100 | ||
101 | static void nfs_dns_ent_put(struct kref *ref) | |
102 | { | |
103 | struct nfs_dns_ent *item; | |
104 | ||
105 | item = container_of(ref, struct nfs_dns_ent, h.ref); | |
106 | kfree(item->hostname); | |
107 | kfree(item); | |
108 | } | |
109 | ||
110 | static struct cache_head *nfs_dns_ent_alloc(void) | |
111 | { | |
112 | struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL); | |
113 | ||
114 | if (item != NULL) { | |
115 | item->hostname = NULL; | |
116 | item->namelen = 0; | |
117 | item->addrlen = 0; | |
118 | return &item->h; | |
119 | } | |
120 | return NULL; | |
121 | }; | |
122 | ||
123 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) | |
124 | { | |
125 | return hash_str(key->hostname, NFS_DNS_HASHBITS); | |
126 | } | |
127 | ||
128 | static void nfs_dns_request(struct cache_detail *cd, | |
129 | struct cache_head *ch, | |
130 | char **bpp, int *blen) | |
131 | { | |
132 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
133 | ||
134 | qword_add(bpp, blen, key->hostname); | |
135 | (*bpp)[-1] = '\n'; | |
136 | } | |
137 | ||
138 | static int nfs_dns_upcall(struct cache_detail *cd, | |
139 | struct cache_head *ch) | |
140 | { | |
141 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
142 | int ret; | |
143 | ||
144 | ret = nfs_cache_upcall(cd, key->hostname); | |
145 | if (ret) | |
21cd1254 | 146 | ret = sunrpc_cache_pipe_upcall(cd, ch); |
e571cbf1 TM |
147 | return ret; |
148 | } | |
149 | ||
150 | static int nfs_dns_match(struct cache_head *ca, | |
151 | struct cache_head *cb) | |
152 | { | |
153 | struct nfs_dns_ent *a; | |
154 | struct nfs_dns_ent *b; | |
155 | ||
156 | a = container_of(ca, struct nfs_dns_ent, h); | |
157 | b = container_of(cb, struct nfs_dns_ent, h); | |
158 | ||
159 | if (a->namelen == 0 || a->namelen != b->namelen) | |
160 | return 0; | |
161 | return memcmp(a->hostname, b->hostname, a->namelen) == 0; | |
162 | } | |
163 | ||
164 | static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd, | |
165 | struct cache_head *h) | |
166 | { | |
167 | struct nfs_dns_ent *item; | |
168 | long ttl; | |
169 | ||
170 | if (h == NULL) { | |
171 | seq_puts(m, "# ip address hostname ttl\n"); | |
172 | return 0; | |
173 | } | |
174 | item = container_of(h, struct nfs_dns_ent, h); | |
c5b29f88 | 175 | ttl = item->h.expiry_time - seconds_since_boot(); |
e571cbf1 TM |
176 | if (ttl < 0) |
177 | ttl = 0; | |
178 | ||
179 | if (!test_bit(CACHE_NEGATIVE, &h->flags)) { | |
180 | char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1]; | |
181 | ||
182 | rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf)); | |
183 | seq_printf(m, "%15s ", buf); | |
184 | } else | |
185 | seq_puts(m, "<none> "); | |
186 | seq_printf(m, "%15s %ld\n", item->hostname, ttl); | |
187 | return 0; | |
188 | } | |
189 | ||
0a6566ec | 190 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
e571cbf1 TM |
191 | struct nfs_dns_ent *key) |
192 | { | |
193 | struct cache_head *ch; | |
194 | ||
195 | ch = sunrpc_cache_lookup(cd, | |
196 | &key->h, | |
197 | nfs_dns_hash(key)); | |
198 | if (!ch) | |
199 | return NULL; | |
200 | return container_of(ch, struct nfs_dns_ent, h); | |
201 | } | |
202 | ||
0a6566ec | 203 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
e571cbf1 TM |
204 | struct nfs_dns_ent *new, |
205 | struct nfs_dns_ent *key) | |
206 | { | |
207 | struct cache_head *ch; | |
208 | ||
209 | ch = sunrpc_cache_update(cd, | |
210 | &new->h, &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 | ||
217 | static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) | |
218 | { | |
219 | char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; | |
220 | struct nfs_dns_ent key, *item; | |
8d96b106 | 221 | unsigned int ttl; |
e571cbf1 TM |
222 | ssize_t len; |
223 | int ret = -EINVAL; | |
224 | ||
225 | if (buf[buflen-1] != '\n') | |
226 | goto out; | |
227 | buf[buflen-1] = '\0'; | |
228 | ||
229 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
230 | if (len <= 0) | |
231 | goto out; | |
599ec129 | 232 | key.addrlen = rpc_pton(cd->net, buf1, len, |
e571cbf1 TM |
233 | (struct sockaddr *)&key.addr, |
234 | sizeof(key.addr)); | |
235 | ||
236 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
237 | if (len <= 0) | |
238 | goto out; | |
239 | ||
240 | key.hostname = buf1; | |
241 | key.namelen = len; | |
242 | memset(&key.h, 0, sizeof(key.h)); | |
243 | ||
8d96b106 N |
244 | if (get_uint(&buf, &ttl) < 0) |
245 | goto out; | |
e571cbf1 TM |
246 | if (ttl == 0) |
247 | goto out; | |
c5b29f88 | 248 | key.h.expiry_time = ttl + seconds_since_boot(); |
e571cbf1 TM |
249 | |
250 | ret = -ENOMEM; | |
251 | item = nfs_dns_lookup(cd, &key); | |
252 | if (item == NULL) | |
253 | goto out; | |
254 | ||
255 | if (key.addrlen == 0) | |
256 | set_bit(CACHE_NEGATIVE, &key.h.flags); | |
257 | ||
258 | item = nfs_dns_update(cd, &key, item); | |
259 | if (item == NULL) | |
260 | goto out; | |
261 | ||
262 | ret = 0; | |
263 | cache_put(&item->h, cd); | |
264 | out: | |
265 | return ret; | |
266 | } | |
267 | ||
e571cbf1 TM |
268 | static int do_cache_lookup(struct cache_detail *cd, |
269 | struct nfs_dns_ent *key, | |
270 | struct nfs_dns_ent **item, | |
271 | struct nfs_cache_defer_req *dreq) | |
272 | { | |
273 | int ret = -ENOMEM; | |
274 | ||
275 | *item = nfs_dns_lookup(cd, key); | |
276 | if (*item) { | |
277 | ret = cache_check(cd, &(*item)->h, &dreq->req); | |
278 | if (ret) | |
279 | *item = NULL; | |
280 | } | |
281 | return ret; | |
282 | } | |
283 | ||
284 | static int do_cache_lookup_nowait(struct cache_detail *cd, | |
285 | struct nfs_dns_ent *key, | |
286 | struct nfs_dns_ent **item) | |
287 | { | |
288 | int ret = -ENOMEM; | |
289 | ||
290 | *item = nfs_dns_lookup(cd, key); | |
291 | if (!*item) | |
292 | goto out_err; | |
293 | ret = -ETIMEDOUT; | |
294 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) | |
c5b29f88 | 295 | || (*item)->h.expiry_time < seconds_since_boot() |
e571cbf1 TM |
296 | || cd->flush_time > (*item)->h.last_refresh) |
297 | goto out_put; | |
298 | ret = -ENOENT; | |
299 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) | |
300 | goto out_put; | |
301 | return 0; | |
302 | out_put: | |
303 | cache_put(&(*item)->h, cd); | |
304 | out_err: | |
305 | *item = NULL; | |
306 | return ret; | |
307 | } | |
308 | ||
309 | static int do_cache_lookup_wait(struct cache_detail *cd, | |
310 | struct nfs_dns_ent *key, | |
311 | struct nfs_dns_ent **item) | |
312 | { | |
313 | struct nfs_cache_defer_req *dreq; | |
314 | int ret = -ENOMEM; | |
315 | ||
316 | dreq = nfs_cache_defer_req_alloc(); | |
317 | if (!dreq) | |
318 | goto out; | |
319 | ret = do_cache_lookup(cd, key, item, dreq); | |
320 | if (ret == -EAGAIN) { | |
321 | ret = nfs_cache_wait_for_upcall(dreq); | |
322 | if (!ret) | |
323 | ret = do_cache_lookup_nowait(cd, key, item); | |
324 | } | |
325 | nfs_cache_defer_req_put(dreq); | |
326 | out: | |
327 | return ret; | |
328 | } | |
329 | ||
1b340d01 SK |
330 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, |
331 | size_t namelen, struct sockaddr *sa, size_t salen) | |
e571cbf1 TM |
332 | { |
333 | struct nfs_dns_ent key = { | |
334 | .hostname = name, | |
335 | .namelen = namelen, | |
336 | }; | |
337 | struct nfs_dns_ent *item = NULL; | |
338 | ssize_t ret; | |
1b340d01 | 339 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
e571cbf1 | 340 | |
1b340d01 | 341 | ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item); |
e571cbf1 TM |
342 | if (ret == 0) { |
343 | if (salen >= item->addrlen) { | |
344 | memcpy(sa, &item->addr, item->addrlen); | |
345 | ret = item->addrlen; | |
346 | } else | |
347 | ret = -EOVERFLOW; | |
1b340d01 | 348 | cache_put(&item->h, nn->nfs_dns_resolve); |
e571cbf1 TM |
349 | } else if (ret == -ENOENT) |
350 | ret = -ESRCH; | |
351 | return ret; | |
352 | } | |
353 | ||
483479c2 SK |
354 | static struct cache_detail nfs_dns_resolve_template = { |
355 | .owner = THIS_MODULE, | |
356 | .hash_size = NFS_DNS_HASHTBL_SIZE, | |
357 | .name = "dns_resolve", | |
358 | .cache_put = nfs_dns_ent_put, | |
359 | .cache_upcall = nfs_dns_upcall, | |
73fb847a | 360 | .cache_request = nfs_dns_request, |
483479c2 SK |
361 | .cache_parse = nfs_dns_parse, |
362 | .cache_show = nfs_dns_show, | |
363 | .match = nfs_dns_match, | |
364 | .init = nfs_dns_ent_init, | |
365 | .update = nfs_dns_ent_update, | |
366 | .alloc = nfs_dns_ent_alloc, | |
367 | }; | |
368 | ||
369 | ||
1b340d01 | 370 | int nfs_dns_resolver_cache_init(struct net *net) |
e571cbf1 | 371 | { |
483479c2 | 372 | int err; |
1b340d01 | 373 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
1b340d01 | 374 | |
483479c2 SK |
375 | nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net); |
376 | if (IS_ERR(nn->nfs_dns_resolve)) | |
377 | return PTR_ERR(nn->nfs_dns_resolve); | |
378 | ||
483479c2 | 379 | err = nfs_cache_register_net(net, nn->nfs_dns_resolve); |
1b340d01 SK |
380 | if (err) |
381 | goto err_reg; | |
1b340d01 | 382 | return 0; |
9222b955 | 383 | |
1b340d01 | 384 | err_reg: |
483479c2 | 385 | cache_destroy_net(nn->nfs_dns_resolve, net); |
1b340d01 SK |
386 | return err; |
387 | } | |
388 | ||
389 | void nfs_dns_resolver_cache_destroy(struct net *net) | |
390 | { | |
391 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
1b340d01 | 392 | |
462b8f6b | 393 | nfs_cache_unregister_net(net, nn->nfs_dns_resolve); |
483479c2 | 394 | cache_destroy_net(nn->nfs_dns_resolve, net); |
1b340d01 SK |
395 | } |
396 | ||
c8d74d9b TM |
397 | static int nfs4_dns_net_init(struct net *net) |
398 | { | |
399 | return nfs_dns_resolver_cache_init(net); | |
400 | } | |
401 | ||
402 | static void nfs4_dns_net_exit(struct net *net) | |
403 | { | |
404 | nfs_dns_resolver_cache_destroy(net); | |
405 | } | |
406 | ||
407 | static struct pernet_operations nfs4_dns_resolver_ops = { | |
408 | .init = nfs4_dns_net_init, | |
409 | .exit = nfs4_dns_net_exit, | |
410 | }; | |
411 | ||
9df69c81 SK |
412 | static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event, |
413 | void *ptr) | |
414 | { | |
415 | struct super_block *sb = ptr; | |
416 | struct net *net = sb->s_fs_info; | |
417 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
418 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
419 | int ret = 0; | |
420 | ||
421 | if (cd == NULL) | |
422 | return 0; | |
423 | ||
424 | if (!try_module_get(THIS_MODULE)) | |
425 | return 0; | |
426 | ||
427 | switch (event) { | |
428 | case RPC_PIPEFS_MOUNT: | |
429 | ret = nfs_cache_register_sb(sb, cd); | |
430 | break; | |
431 | case RPC_PIPEFS_UMOUNT: | |
432 | nfs_cache_unregister_sb(sb, cd); | |
433 | break; | |
434 | default: | |
435 | ret = -ENOTSUPP; | |
436 | break; | |
437 | } | |
438 | module_put(THIS_MODULE); | |
439 | return ret; | |
440 | } | |
441 | ||
442 | static struct notifier_block nfs_dns_resolver_block = { | |
443 | .notifier_call = rpc_pipefs_event, | |
444 | }; | |
445 | ||
1b340d01 SK |
446 | int nfs_dns_resolver_init(void) |
447 | { | |
c8d74d9b TM |
448 | int err; |
449 | ||
450 | err = register_pernet_subsys(&nfs4_dns_resolver_ops); | |
451 | if (err < 0) | |
452 | goto out; | |
453 | err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block); | |
454 | if (err < 0) | |
455 | goto out1; | |
456 | return 0; | |
457 | out1: | |
458 | unregister_pernet_subsys(&nfs4_dns_resolver_ops); | |
459 | out: | |
460 | return err; | |
e571cbf1 TM |
461 | } |
462 | ||
463 | void nfs_dns_resolver_destroy(void) | |
464 | { | |
9df69c81 | 465 | rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block); |
c8d74d9b | 466 | unregister_pernet_subsys(&nfs4_dns_resolver_ops); |
e571cbf1 | 467 | } |
c2e8139c | 468 | #endif |