Commit | Line | Data |
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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 | } | |
89d77c8f | 32 | EXPORT_SYMBOL_GPL(nfs_dns_resolve_name); |
c2e8139c BS |
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> |
e571cbf1 TM |
50 | |
51 | #include "dns_resolve.h" | |
52 | #include "cache_lib.h" | |
1b340d01 | 53 | #include "netns.h" |
e571cbf1 TM |
54 | |
55 | #define NFS_DNS_HASHBITS 4 | |
56 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) | |
57 | ||
e571cbf1 TM |
58 | struct nfs_dns_ent { |
59 | struct cache_head h; | |
60 | ||
61 | char *hostname; | |
62 | size_t namelen; | |
63 | ||
64 | struct sockaddr_storage addr; | |
65 | size_t addrlen; | |
66 | }; | |
67 | ||
68 | ||
ebed9203 TM |
69 | static void nfs_dns_ent_update(struct cache_head *cnew, |
70 | struct cache_head *ckey) | |
71 | { | |
72 | struct nfs_dns_ent *new; | |
73 | struct nfs_dns_ent *key; | |
74 | ||
75 | new = container_of(cnew, struct nfs_dns_ent, h); | |
76 | key = container_of(ckey, struct nfs_dns_ent, h); | |
77 | ||
78 | memcpy(&new->addr, &key->addr, key->addrlen); | |
79 | new->addrlen = key->addrlen; | |
80 | } | |
81 | ||
e571cbf1 TM |
82 | static void nfs_dns_ent_init(struct cache_head *cnew, |
83 | struct cache_head *ckey) | |
84 | { | |
85 | struct nfs_dns_ent *new; | |
86 | struct nfs_dns_ent *key; | |
87 | ||
88 | new = container_of(cnew, struct nfs_dns_ent, h); | |
89 | key = container_of(ckey, struct nfs_dns_ent, h); | |
90 | ||
91 | kfree(new->hostname); | |
92 | new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL); | |
93 | if (new->hostname) { | |
94 | new->namelen = key->namelen; | |
ebed9203 | 95 | nfs_dns_ent_update(cnew, ckey); |
e571cbf1 TM |
96 | } else { |
97 | new->namelen = 0; | |
98 | new->addrlen = 0; | |
99 | } | |
100 | } | |
101 | ||
102 | static void nfs_dns_ent_put(struct kref *ref) | |
103 | { | |
104 | struct nfs_dns_ent *item; | |
105 | ||
106 | item = container_of(ref, struct nfs_dns_ent, h.ref); | |
107 | kfree(item->hostname); | |
108 | kfree(item); | |
109 | } | |
110 | ||
111 | static struct cache_head *nfs_dns_ent_alloc(void) | |
112 | { | |
113 | struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL); | |
114 | ||
115 | if (item != NULL) { | |
116 | item->hostname = NULL; | |
117 | item->namelen = 0; | |
118 | item->addrlen = 0; | |
119 | return &item->h; | |
120 | } | |
121 | return NULL; | |
122 | }; | |
123 | ||
124 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) | |
125 | { | |
126 | return hash_str(key->hostname, NFS_DNS_HASHBITS); | |
127 | } | |
128 | ||
129 | static void nfs_dns_request(struct cache_detail *cd, | |
130 | struct cache_head *ch, | |
131 | char **bpp, int *blen) | |
132 | { | |
133 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
134 | ||
135 | qword_add(bpp, blen, key->hostname); | |
136 | (*bpp)[-1] = '\n'; | |
137 | } | |
138 | ||
139 | static int nfs_dns_upcall(struct cache_detail *cd, | |
140 | struct cache_head *ch) | |
141 | { | |
142 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
143 | int ret; | |
144 | ||
145 | ret = nfs_cache_upcall(cd, key->hostname); | |
146 | if (ret) | |
147 | ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request); | |
148 | return ret; | |
149 | } | |
150 | ||
151 | static int nfs_dns_match(struct cache_head *ca, | |
152 | struct cache_head *cb) | |
153 | { | |
154 | struct nfs_dns_ent *a; | |
155 | struct nfs_dns_ent *b; | |
156 | ||
157 | a = container_of(ca, struct nfs_dns_ent, h); | |
158 | b = container_of(cb, struct nfs_dns_ent, h); | |
159 | ||
160 | if (a->namelen == 0 || a->namelen != b->namelen) | |
161 | return 0; | |
162 | return memcmp(a->hostname, b->hostname, a->namelen) == 0; | |
163 | } | |
164 | ||
165 | static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd, | |
166 | struct cache_head *h) | |
167 | { | |
168 | struct nfs_dns_ent *item; | |
169 | long ttl; | |
170 | ||
171 | if (h == NULL) { | |
172 | seq_puts(m, "# ip address hostname ttl\n"); | |
173 | return 0; | |
174 | } | |
175 | item = container_of(h, struct nfs_dns_ent, h); | |
c5b29f88 | 176 | ttl = item->h.expiry_time - seconds_since_boot(); |
e571cbf1 TM |
177 | if (ttl < 0) |
178 | ttl = 0; | |
179 | ||
180 | if (!test_bit(CACHE_NEGATIVE, &h->flags)) { | |
181 | char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1]; | |
182 | ||
183 | rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf)); | |
184 | seq_printf(m, "%15s ", buf); | |
185 | } else | |
186 | seq_puts(m, "<none> "); | |
187 | seq_printf(m, "%15s %ld\n", item->hostname, ttl); | |
188 | return 0; | |
189 | } | |
190 | ||
0a6566ec | 191 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
e571cbf1 TM |
192 | struct nfs_dns_ent *key) |
193 | { | |
194 | struct cache_head *ch; | |
195 | ||
196 | ch = sunrpc_cache_lookup(cd, | |
197 | &key->h, | |
198 | nfs_dns_hash(key)); | |
199 | if (!ch) | |
200 | return NULL; | |
201 | return container_of(ch, struct nfs_dns_ent, h); | |
202 | } | |
203 | ||
0a6566ec | 204 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
e571cbf1 TM |
205 | struct nfs_dns_ent *new, |
206 | struct nfs_dns_ent *key) | |
207 | { | |
208 | struct cache_head *ch; | |
209 | ||
210 | ch = sunrpc_cache_update(cd, | |
211 | &new->h, &key->h, | |
212 | nfs_dns_hash(key)); | |
213 | if (!ch) | |
214 | return NULL; | |
215 | return container_of(ch, struct nfs_dns_ent, h); | |
216 | } | |
217 | ||
218 | static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) | |
219 | { | |
220 | char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; | |
221 | struct nfs_dns_ent key, *item; | |
8d96b106 | 222 | unsigned int ttl; |
e571cbf1 TM |
223 | ssize_t len; |
224 | int ret = -EINVAL; | |
225 | ||
226 | if (buf[buflen-1] != '\n') | |
227 | goto out; | |
228 | buf[buflen-1] = '\0'; | |
229 | ||
230 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
231 | if (len <= 0) | |
232 | goto out; | |
599ec129 | 233 | key.addrlen = rpc_pton(cd->net, buf1, len, |
e571cbf1 TM |
234 | (struct sockaddr *)&key.addr, |
235 | sizeof(key.addr)); | |
236 | ||
237 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
238 | if (len <= 0) | |
239 | goto out; | |
240 | ||
241 | key.hostname = buf1; | |
242 | key.namelen = len; | |
243 | memset(&key.h, 0, sizeof(key.h)); | |
244 | ||
8d96b106 N |
245 | if (get_uint(&buf, &ttl) < 0) |
246 | goto out; | |
e571cbf1 TM |
247 | if (ttl == 0) |
248 | goto out; | |
c5b29f88 | 249 | key.h.expiry_time = ttl + seconds_since_boot(); |
e571cbf1 TM |
250 | |
251 | ret = -ENOMEM; | |
252 | item = nfs_dns_lookup(cd, &key); | |
253 | if (item == NULL) | |
254 | goto out; | |
255 | ||
256 | if (key.addrlen == 0) | |
257 | set_bit(CACHE_NEGATIVE, &key.h.flags); | |
258 | ||
259 | item = nfs_dns_update(cd, &key, item); | |
260 | if (item == NULL) | |
261 | goto out; | |
262 | ||
263 | ret = 0; | |
264 | cache_put(&item->h, cd); | |
265 | out: | |
266 | return ret; | |
267 | } | |
268 | ||
e571cbf1 TM |
269 | static int do_cache_lookup(struct cache_detail *cd, |
270 | struct nfs_dns_ent *key, | |
271 | struct nfs_dns_ent **item, | |
272 | struct nfs_cache_defer_req *dreq) | |
273 | { | |
274 | int ret = -ENOMEM; | |
275 | ||
276 | *item = nfs_dns_lookup(cd, key); | |
277 | if (*item) { | |
278 | ret = cache_check(cd, &(*item)->h, &dreq->req); | |
279 | if (ret) | |
280 | *item = NULL; | |
281 | } | |
282 | return ret; | |
283 | } | |
284 | ||
285 | static int do_cache_lookup_nowait(struct cache_detail *cd, | |
286 | struct nfs_dns_ent *key, | |
287 | struct nfs_dns_ent **item) | |
288 | { | |
289 | int ret = -ENOMEM; | |
290 | ||
291 | *item = nfs_dns_lookup(cd, key); | |
292 | if (!*item) | |
293 | goto out_err; | |
294 | ret = -ETIMEDOUT; | |
295 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) | |
c5b29f88 | 296 | || (*item)->h.expiry_time < seconds_since_boot() |
e571cbf1 TM |
297 | || cd->flush_time > (*item)->h.last_refresh) |
298 | goto out_put; | |
299 | ret = -ENOENT; | |
300 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) | |
301 | goto out_put; | |
302 | return 0; | |
303 | out_put: | |
304 | cache_put(&(*item)->h, cd); | |
305 | out_err: | |
306 | *item = NULL; | |
307 | return ret; | |
308 | } | |
309 | ||
310 | static int do_cache_lookup_wait(struct cache_detail *cd, | |
311 | struct nfs_dns_ent *key, | |
312 | struct nfs_dns_ent **item) | |
313 | { | |
314 | struct nfs_cache_defer_req *dreq; | |
315 | int ret = -ENOMEM; | |
316 | ||
317 | dreq = nfs_cache_defer_req_alloc(); | |
318 | if (!dreq) | |
319 | goto out; | |
320 | ret = do_cache_lookup(cd, key, item, dreq); | |
321 | if (ret == -EAGAIN) { | |
322 | ret = nfs_cache_wait_for_upcall(dreq); | |
323 | if (!ret) | |
324 | ret = do_cache_lookup_nowait(cd, key, item); | |
325 | } | |
326 | nfs_cache_defer_req_put(dreq); | |
327 | out: | |
328 | return ret; | |
329 | } | |
330 | ||
1b340d01 SK |
331 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, |
332 | size_t namelen, struct sockaddr *sa, size_t salen) | |
e571cbf1 TM |
333 | { |
334 | struct nfs_dns_ent key = { | |
335 | .hostname = name, | |
336 | .namelen = namelen, | |
337 | }; | |
338 | struct nfs_dns_ent *item = NULL; | |
339 | ssize_t ret; | |
1b340d01 | 340 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
e571cbf1 | 341 | |
1b340d01 | 342 | ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item); |
e571cbf1 TM |
343 | if (ret == 0) { |
344 | if (salen >= item->addrlen) { | |
345 | memcpy(sa, &item->addr, item->addrlen); | |
346 | ret = item->addrlen; | |
347 | } else | |
348 | ret = -EOVERFLOW; | |
1b340d01 | 349 | cache_put(&item->h, nn->nfs_dns_resolve); |
e571cbf1 TM |
350 | } else if (ret == -ENOENT) |
351 | ret = -ESRCH; | |
352 | return ret; | |
353 | } | |
89d77c8f | 354 | EXPORT_SYMBOL_GPL(nfs_dns_resolve_name); |
e571cbf1 | 355 | |
1b340d01 | 356 | int nfs_dns_resolver_cache_init(struct net *net) |
e571cbf1 | 357 | { |
1b340d01 SK |
358 | int err = -ENOMEM; |
359 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
360 | struct cache_detail *cd; | |
361 | struct cache_head **tbl; | |
362 | ||
363 | cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL); | |
364 | if (cd == NULL) | |
365 | goto err_cd; | |
366 | ||
367 | tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *), | |
368 | GFP_KERNEL); | |
369 | if (tbl == NULL) | |
370 | goto err_tbl; | |
371 | ||
372 | cd->owner = THIS_MODULE, | |
373 | cd->hash_size = NFS_DNS_HASHTBL_SIZE, | |
374 | cd->hash_table = tbl, | |
375 | cd->name = "dns_resolve", | |
376 | cd->cache_put = nfs_dns_ent_put, | |
377 | cd->cache_upcall = nfs_dns_upcall, | |
378 | cd->cache_parse = nfs_dns_parse, | |
379 | cd->cache_show = nfs_dns_show, | |
380 | cd->match = nfs_dns_match, | |
381 | cd->init = nfs_dns_ent_init, | |
382 | cd->update = nfs_dns_ent_update, | |
383 | cd->alloc = nfs_dns_ent_alloc, | |
384 | ||
385 | nfs_cache_init(cd); | |
386 | err = nfs_cache_register_net(net, cd); | |
387 | if (err) | |
388 | goto err_reg; | |
389 | nn->nfs_dns_resolve = cd; | |
390 | return 0; | |
9222b955 | 391 | |
1b340d01 SK |
392 | err_reg: |
393 | nfs_cache_destroy(cd); | |
394 | kfree(cd->hash_table); | |
395 | err_tbl: | |
396 | kfree(cd); | |
397 | err_cd: | |
398 | return err; | |
399 | } | |
400 | ||
401 | void nfs_dns_resolver_cache_destroy(struct net *net) | |
402 | { | |
403 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
404 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
405 | ||
406 | nfs_cache_unregister_net(net, cd); | |
407 | nfs_cache_destroy(cd); | |
408 | kfree(cd->hash_table); | |
409 | kfree(cd); | |
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 | { | |
9df69c81 | 448 | return rpc_pipefs_notifier_register(&nfs_dns_resolver_block); |
e571cbf1 TM |
449 | } |
450 | ||
451 | void nfs_dns_resolver_destroy(void) | |
452 | { | |
9df69c81 | 453 | rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block); |
e571cbf1 | 454 | } |
c2e8139c | 455 | #endif |