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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 BS |
12 | #include <linux/sunrpc/clnt.h> |
13 | #include <linux/dns_resolver.h> | |
17280175 | 14 | #include "dns_resolve.h" |
c2e8139c | 15 | |
1b340d01 | 16 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen, |
c2e8139c BS |
17 | struct sockaddr *sa, size_t salen) |
18 | { | |
19 | ssize_t ret; | |
20 | char *ip_addr = NULL; | |
21 | int ip_len; | |
22 | ||
23 | ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL); | |
24 | if (ip_len > 0) | |
bc224f53 | 25 | ret = rpc_pton(net, ip_addr, ip_len, sa, salen); |
c2e8139c BS |
26 | else |
27 | ret = -ESRCH; | |
28 | kfree(ip_addr); | |
29 | return ret; | |
30 | } | |
89d77c8f | 31 | EXPORT_SYMBOL_GPL(nfs_dns_resolve_name); |
c2e8139c BS |
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> | |
45 | #include <linux/sunrpc/cache.h> | |
46 | #include <linux/sunrpc/svcauth.h> | |
9df69c81 | 47 | #include <linux/sunrpc/rpc_pipe_fs.h> |
e571cbf1 TM |
48 | |
49 | #include "dns_resolve.h" | |
50 | #include "cache_lib.h" | |
1b340d01 | 51 | #include "netns.h" |
e571cbf1 TM |
52 | |
53 | #define NFS_DNS_HASHBITS 4 | |
54 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) | |
55 | ||
e571cbf1 TM |
56 | struct nfs_dns_ent { |
57 | struct cache_head h; | |
58 | ||
59 | char *hostname; | |
60 | size_t namelen; | |
61 | ||
62 | struct sockaddr_storage addr; | |
63 | size_t addrlen; | |
64 | }; | |
65 | ||
66 | ||
ebed9203 TM |
67 | static void nfs_dns_ent_update(struct cache_head *cnew, |
68 | struct cache_head *ckey) | |
69 | { | |
70 | struct nfs_dns_ent *new; | |
71 | struct nfs_dns_ent *key; | |
72 | ||
73 | new = container_of(cnew, struct nfs_dns_ent, h); | |
74 | key = container_of(ckey, struct nfs_dns_ent, h); | |
75 | ||
76 | memcpy(&new->addr, &key->addr, key->addrlen); | |
77 | new->addrlen = key->addrlen; | |
78 | } | |
79 | ||
e571cbf1 TM |
80 | static void nfs_dns_ent_init(struct cache_head *cnew, |
81 | struct cache_head *ckey) | |
82 | { | |
83 | struct nfs_dns_ent *new; | |
84 | struct nfs_dns_ent *key; | |
85 | ||
86 | new = container_of(cnew, struct nfs_dns_ent, h); | |
87 | key = container_of(ckey, struct nfs_dns_ent, h); | |
88 | ||
89 | kfree(new->hostname); | |
90 | new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL); | |
91 | if (new->hostname) { | |
92 | new->namelen = key->namelen; | |
ebed9203 | 93 | nfs_dns_ent_update(cnew, ckey); |
e571cbf1 TM |
94 | } else { |
95 | new->namelen = 0; | |
96 | new->addrlen = 0; | |
97 | } | |
98 | } | |
99 | ||
100 | static void nfs_dns_ent_put(struct kref *ref) | |
101 | { | |
102 | struct nfs_dns_ent *item; | |
103 | ||
104 | item = container_of(ref, struct nfs_dns_ent, h.ref); | |
105 | kfree(item->hostname); | |
106 | kfree(item); | |
107 | } | |
108 | ||
109 | static struct cache_head *nfs_dns_ent_alloc(void) | |
110 | { | |
111 | struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL); | |
112 | ||
113 | if (item != NULL) { | |
114 | item->hostname = NULL; | |
115 | item->namelen = 0; | |
116 | item->addrlen = 0; | |
117 | return &item->h; | |
118 | } | |
119 | return NULL; | |
120 | }; | |
121 | ||
122 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) | |
123 | { | |
124 | return hash_str(key->hostname, NFS_DNS_HASHBITS); | |
125 | } | |
126 | ||
127 | static void nfs_dns_request(struct cache_detail *cd, | |
128 | struct cache_head *ch, | |
129 | char **bpp, int *blen) | |
130 | { | |
131 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
132 | ||
133 | qword_add(bpp, blen, key->hostname); | |
134 | (*bpp)[-1] = '\n'; | |
135 | } | |
136 | ||
137 | static int nfs_dns_upcall(struct cache_detail *cd, | |
138 | struct cache_head *ch) | |
139 | { | |
140 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
141 | int ret; | |
142 | ||
143 | ret = nfs_cache_upcall(cd, key->hostname); | |
144 | if (ret) | |
145 | ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request); | |
146 | return ret; | |
147 | } | |
148 | ||
149 | static int nfs_dns_match(struct cache_head *ca, | |
150 | struct cache_head *cb) | |
151 | { | |
152 | struct nfs_dns_ent *a; | |
153 | struct nfs_dns_ent *b; | |
154 | ||
155 | a = container_of(ca, struct nfs_dns_ent, h); | |
156 | b = container_of(cb, struct nfs_dns_ent, h); | |
157 | ||
158 | if (a->namelen == 0 || a->namelen != b->namelen) | |
159 | return 0; | |
160 | return memcmp(a->hostname, b->hostname, a->namelen) == 0; | |
161 | } | |
162 | ||
163 | static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd, | |
164 | struct cache_head *h) | |
165 | { | |
166 | struct nfs_dns_ent *item; | |
167 | long ttl; | |
168 | ||
169 | if (h == NULL) { | |
170 | seq_puts(m, "# ip address hostname ttl\n"); | |
171 | return 0; | |
172 | } | |
173 | item = container_of(h, struct nfs_dns_ent, h); | |
c5b29f88 | 174 | ttl = item->h.expiry_time - seconds_since_boot(); |
e571cbf1 TM |
175 | if (ttl < 0) |
176 | ttl = 0; | |
177 | ||
178 | if (!test_bit(CACHE_NEGATIVE, &h->flags)) { | |
179 | char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1]; | |
180 | ||
181 | rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf)); | |
182 | seq_printf(m, "%15s ", buf); | |
183 | } else | |
184 | seq_puts(m, "<none> "); | |
185 | seq_printf(m, "%15s %ld\n", item->hostname, ttl); | |
186 | return 0; | |
187 | } | |
188 | ||
0a6566ec | 189 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
e571cbf1 TM |
190 | struct nfs_dns_ent *key) |
191 | { | |
192 | struct cache_head *ch; | |
193 | ||
194 | ch = sunrpc_cache_lookup(cd, | |
195 | &key->h, | |
196 | nfs_dns_hash(key)); | |
197 | if (!ch) | |
198 | return NULL; | |
199 | return container_of(ch, struct nfs_dns_ent, h); | |
200 | } | |
201 | ||
0a6566ec | 202 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
e571cbf1 TM |
203 | struct nfs_dns_ent *new, |
204 | struct nfs_dns_ent *key) | |
205 | { | |
206 | struct cache_head *ch; | |
207 | ||
208 | ch = sunrpc_cache_update(cd, | |
209 | &new->h, &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 | ||
216 | static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) | |
217 | { | |
218 | char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; | |
219 | struct nfs_dns_ent key, *item; | |
220 | unsigned long ttl; | |
221 | ssize_t len; | |
222 | int ret = -EINVAL; | |
223 | ||
224 | if (buf[buflen-1] != '\n') | |
225 | goto out; | |
226 | buf[buflen-1] = '\0'; | |
227 | ||
228 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
229 | if (len <= 0) | |
230 | goto out; | |
599ec129 | 231 | key.addrlen = rpc_pton(cd->net, buf1, len, |
e571cbf1 TM |
232 | (struct sockaddr *)&key.addr, |
233 | sizeof(key.addr)); | |
234 | ||
235 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
236 | if (len <= 0) | |
237 | goto out; | |
238 | ||
239 | key.hostname = buf1; | |
240 | key.namelen = len; | |
241 | memset(&key.h, 0, sizeof(key.h)); | |
242 | ||
243 | ttl = get_expiry(&buf); | |
244 | if (ttl == 0) | |
245 | goto out; | |
c5b29f88 | 246 | key.h.expiry_time = ttl + seconds_since_boot(); |
e571cbf1 TM |
247 | |
248 | ret = -ENOMEM; | |
249 | item = nfs_dns_lookup(cd, &key); | |
250 | if (item == NULL) | |
251 | goto out; | |
252 | ||
253 | if (key.addrlen == 0) | |
254 | set_bit(CACHE_NEGATIVE, &key.h.flags); | |
255 | ||
256 | item = nfs_dns_update(cd, &key, item); | |
257 | if (item == NULL) | |
258 | goto out; | |
259 | ||
260 | ret = 0; | |
261 | cache_put(&item->h, cd); | |
262 | out: | |
263 | return ret; | |
264 | } | |
265 | ||
e571cbf1 TM |
266 | static int do_cache_lookup(struct cache_detail *cd, |
267 | struct nfs_dns_ent *key, | |
268 | struct nfs_dns_ent **item, | |
269 | struct nfs_cache_defer_req *dreq) | |
270 | { | |
271 | int ret = -ENOMEM; | |
272 | ||
273 | *item = nfs_dns_lookup(cd, key); | |
274 | if (*item) { | |
275 | ret = cache_check(cd, &(*item)->h, &dreq->req); | |
276 | if (ret) | |
277 | *item = NULL; | |
278 | } | |
279 | return ret; | |
280 | } | |
281 | ||
282 | static int do_cache_lookup_nowait(struct cache_detail *cd, | |
283 | struct nfs_dns_ent *key, | |
284 | struct nfs_dns_ent **item) | |
285 | { | |
286 | int ret = -ENOMEM; | |
287 | ||
288 | *item = nfs_dns_lookup(cd, key); | |
289 | if (!*item) | |
290 | goto out_err; | |
291 | ret = -ETIMEDOUT; | |
292 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) | |
c5b29f88 | 293 | || (*item)->h.expiry_time < seconds_since_boot() |
e571cbf1 TM |
294 | || cd->flush_time > (*item)->h.last_refresh) |
295 | goto out_put; | |
296 | ret = -ENOENT; | |
297 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) | |
298 | goto out_put; | |
299 | return 0; | |
300 | out_put: | |
301 | cache_put(&(*item)->h, cd); | |
302 | out_err: | |
303 | *item = NULL; | |
304 | return ret; | |
305 | } | |
306 | ||
307 | static int do_cache_lookup_wait(struct cache_detail *cd, | |
308 | struct nfs_dns_ent *key, | |
309 | struct nfs_dns_ent **item) | |
310 | { | |
311 | struct nfs_cache_defer_req *dreq; | |
312 | int ret = -ENOMEM; | |
313 | ||
314 | dreq = nfs_cache_defer_req_alloc(); | |
315 | if (!dreq) | |
316 | goto out; | |
317 | ret = do_cache_lookup(cd, key, item, dreq); | |
318 | if (ret == -EAGAIN) { | |
319 | ret = nfs_cache_wait_for_upcall(dreq); | |
320 | if (!ret) | |
321 | ret = do_cache_lookup_nowait(cd, key, item); | |
322 | } | |
323 | nfs_cache_defer_req_put(dreq); | |
324 | out: | |
325 | return ret; | |
326 | } | |
327 | ||
1b340d01 SK |
328 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, |
329 | size_t namelen, struct sockaddr *sa, size_t salen) | |
e571cbf1 TM |
330 | { |
331 | struct nfs_dns_ent key = { | |
332 | .hostname = name, | |
333 | .namelen = namelen, | |
334 | }; | |
335 | struct nfs_dns_ent *item = NULL; | |
336 | ssize_t ret; | |
1b340d01 | 337 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
e571cbf1 | 338 | |
1b340d01 | 339 | ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item); |
e571cbf1 TM |
340 | if (ret == 0) { |
341 | if (salen >= item->addrlen) { | |
342 | memcpy(sa, &item->addr, item->addrlen); | |
343 | ret = item->addrlen; | |
344 | } else | |
345 | ret = -EOVERFLOW; | |
1b340d01 | 346 | cache_put(&item->h, nn->nfs_dns_resolve); |
e571cbf1 TM |
347 | } else if (ret == -ENOENT) |
348 | ret = -ESRCH; | |
349 | return ret; | |
350 | } | |
89d77c8f | 351 | EXPORT_SYMBOL_GPL(nfs_dns_resolve_name); |
e571cbf1 | 352 | |
1b340d01 | 353 | int nfs_dns_resolver_cache_init(struct net *net) |
e571cbf1 | 354 | { |
1b340d01 SK |
355 | int err = -ENOMEM; |
356 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
357 | struct cache_detail *cd; | |
358 | struct cache_head **tbl; | |
359 | ||
360 | cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL); | |
361 | if (cd == NULL) | |
362 | goto err_cd; | |
363 | ||
364 | tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *), | |
365 | GFP_KERNEL); | |
366 | if (tbl == NULL) | |
367 | goto err_tbl; | |
368 | ||
369 | cd->owner = THIS_MODULE, | |
370 | cd->hash_size = NFS_DNS_HASHTBL_SIZE, | |
371 | cd->hash_table = tbl, | |
372 | cd->name = "dns_resolve", | |
373 | cd->cache_put = nfs_dns_ent_put, | |
374 | cd->cache_upcall = nfs_dns_upcall, | |
375 | cd->cache_parse = nfs_dns_parse, | |
376 | cd->cache_show = nfs_dns_show, | |
377 | cd->match = nfs_dns_match, | |
378 | cd->init = nfs_dns_ent_init, | |
379 | cd->update = nfs_dns_ent_update, | |
380 | cd->alloc = nfs_dns_ent_alloc, | |
381 | ||
382 | nfs_cache_init(cd); | |
383 | err = nfs_cache_register_net(net, cd); | |
384 | if (err) | |
385 | goto err_reg; | |
386 | nn->nfs_dns_resolve = cd; | |
387 | return 0; | |
9222b955 | 388 | |
1b340d01 SK |
389 | err_reg: |
390 | nfs_cache_destroy(cd); | |
391 | kfree(cd->hash_table); | |
392 | err_tbl: | |
393 | kfree(cd); | |
394 | err_cd: | |
395 | return err; | |
396 | } | |
397 | ||
398 | void nfs_dns_resolver_cache_destroy(struct net *net) | |
399 | { | |
400 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
401 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
402 | ||
403 | nfs_cache_unregister_net(net, cd); | |
404 | nfs_cache_destroy(cd); | |
405 | kfree(cd->hash_table); | |
406 | kfree(cd); | |
407 | } | |
408 | ||
9df69c81 SK |
409 | static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event, |
410 | void *ptr) | |
411 | { | |
412 | struct super_block *sb = ptr; | |
413 | struct net *net = sb->s_fs_info; | |
414 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
415 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
416 | int ret = 0; | |
417 | ||
418 | if (cd == NULL) | |
419 | return 0; | |
420 | ||
421 | if (!try_module_get(THIS_MODULE)) | |
422 | return 0; | |
423 | ||
424 | switch (event) { | |
425 | case RPC_PIPEFS_MOUNT: | |
426 | ret = nfs_cache_register_sb(sb, cd); | |
427 | break; | |
428 | case RPC_PIPEFS_UMOUNT: | |
429 | nfs_cache_unregister_sb(sb, cd); | |
430 | break; | |
431 | default: | |
432 | ret = -ENOTSUPP; | |
433 | break; | |
434 | } | |
435 | module_put(THIS_MODULE); | |
436 | return ret; | |
437 | } | |
438 | ||
439 | static struct notifier_block nfs_dns_resolver_block = { | |
440 | .notifier_call = rpc_pipefs_event, | |
441 | }; | |
442 | ||
1b340d01 SK |
443 | int nfs_dns_resolver_init(void) |
444 | { | |
9df69c81 | 445 | return rpc_pipefs_notifier_register(&nfs_dns_resolver_block); |
e571cbf1 TM |
446 | } |
447 | ||
448 | void nfs_dns_resolver_destroy(void) | |
449 | { | |
9df69c81 | 450 | rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block); |
e571cbf1 | 451 | } |
c2e8139c | 452 | #endif |