]>
Commit | Line | Data |
---|---|---|
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 | ||
11 | #include <linux/sunrpc/clnt.h> | |
12 | #include <linux/dns_resolver.h> | |
13 | ||
1b340d01 | 14 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen, |
c2e8139c BS |
15 | struct sockaddr *sa, size_t salen) |
16 | { | |
17 | ssize_t ret; | |
18 | char *ip_addr = NULL; | |
19 | int ip_len; | |
20 | ||
21 | ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL); | |
22 | if (ip_len > 0) | |
bc224f53 | 23 | ret = rpc_pton(net, ip_addr, ip_len, sa, salen); |
c2e8139c BS |
24 | else |
25 | ret = -ESRCH; | |
26 | kfree(ip_addr); | |
27 | return ret; | |
28 | } | |
29 | ||
30 | #else | |
31 | ||
e571cbf1 TM |
32 | #include <linux/hash.h> |
33 | #include <linux/string.h> | |
34 | #include <linux/kmod.h> | |
5a0e3ad6 | 35 | #include <linux/slab.h> |
e571cbf1 TM |
36 | #include <linux/module.h> |
37 | #include <linux/socket.h> | |
38 | #include <linux/seq_file.h> | |
39 | #include <linux/inet.h> | |
40 | #include <linux/sunrpc/clnt.h> | |
41 | #include <linux/sunrpc/cache.h> | |
42 | #include <linux/sunrpc/svcauth.h> | |
9df69c81 | 43 | #include <linux/sunrpc/rpc_pipe_fs.h> |
e571cbf1 TM |
44 | |
45 | #include "dns_resolve.h" | |
46 | #include "cache_lib.h" | |
1b340d01 | 47 | #include "netns.h" |
e571cbf1 TM |
48 | |
49 | #define NFS_DNS_HASHBITS 4 | |
50 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) | |
51 | ||
e571cbf1 TM |
52 | struct nfs_dns_ent { |
53 | struct cache_head h; | |
54 | ||
55 | char *hostname; | |
56 | size_t namelen; | |
57 | ||
58 | struct sockaddr_storage addr; | |
59 | size_t addrlen; | |
60 | }; | |
61 | ||
62 | ||
ebed9203 TM |
63 | static void nfs_dns_ent_update(struct cache_head *cnew, |
64 | struct cache_head *ckey) | |
65 | { | |
66 | struct nfs_dns_ent *new; | |
67 | struct nfs_dns_ent *key; | |
68 | ||
69 | new = container_of(cnew, struct nfs_dns_ent, h); | |
70 | key = container_of(ckey, struct nfs_dns_ent, h); | |
71 | ||
72 | memcpy(&new->addr, &key->addr, key->addrlen); | |
73 | new->addrlen = key->addrlen; | |
74 | } | |
75 | ||
e571cbf1 TM |
76 | static void nfs_dns_ent_init(struct cache_head *cnew, |
77 | struct cache_head *ckey) | |
78 | { | |
79 | struct nfs_dns_ent *new; | |
80 | struct nfs_dns_ent *key; | |
81 | ||
82 | new = container_of(cnew, struct nfs_dns_ent, h); | |
83 | key = container_of(ckey, struct nfs_dns_ent, h); | |
84 | ||
85 | kfree(new->hostname); | |
86 | new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL); | |
87 | if (new->hostname) { | |
88 | new->namelen = key->namelen; | |
ebed9203 | 89 | nfs_dns_ent_update(cnew, ckey); |
e571cbf1 TM |
90 | } else { |
91 | new->namelen = 0; | |
92 | new->addrlen = 0; | |
93 | } | |
94 | } | |
95 | ||
96 | static void nfs_dns_ent_put(struct kref *ref) | |
97 | { | |
98 | struct nfs_dns_ent *item; | |
99 | ||
100 | item = container_of(ref, struct nfs_dns_ent, h.ref); | |
101 | kfree(item->hostname); | |
102 | kfree(item); | |
103 | } | |
104 | ||
105 | static struct cache_head *nfs_dns_ent_alloc(void) | |
106 | { | |
107 | struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL); | |
108 | ||
109 | if (item != NULL) { | |
110 | item->hostname = NULL; | |
111 | item->namelen = 0; | |
112 | item->addrlen = 0; | |
113 | return &item->h; | |
114 | } | |
115 | return NULL; | |
116 | }; | |
117 | ||
118 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) | |
119 | { | |
120 | return hash_str(key->hostname, NFS_DNS_HASHBITS); | |
121 | } | |
122 | ||
123 | static void nfs_dns_request(struct cache_detail *cd, | |
124 | struct cache_head *ch, | |
125 | char **bpp, int *blen) | |
126 | { | |
127 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
128 | ||
129 | qword_add(bpp, blen, key->hostname); | |
130 | (*bpp)[-1] = '\n'; | |
131 | } | |
132 | ||
133 | static int nfs_dns_upcall(struct cache_detail *cd, | |
134 | struct cache_head *ch) | |
135 | { | |
136 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
137 | int ret; | |
138 | ||
139 | ret = nfs_cache_upcall(cd, key->hostname); | |
140 | if (ret) | |
141 | ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request); | |
142 | return ret; | |
143 | } | |
144 | ||
145 | static int nfs_dns_match(struct cache_head *ca, | |
146 | struct cache_head *cb) | |
147 | { | |
148 | struct nfs_dns_ent *a; | |
149 | struct nfs_dns_ent *b; | |
150 | ||
151 | a = container_of(ca, struct nfs_dns_ent, h); | |
152 | b = container_of(cb, struct nfs_dns_ent, h); | |
153 | ||
154 | if (a->namelen == 0 || a->namelen != b->namelen) | |
155 | return 0; | |
156 | return memcmp(a->hostname, b->hostname, a->namelen) == 0; | |
157 | } | |
158 | ||
159 | static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd, | |
160 | struct cache_head *h) | |
161 | { | |
162 | struct nfs_dns_ent *item; | |
163 | long ttl; | |
164 | ||
165 | if (h == NULL) { | |
166 | seq_puts(m, "# ip address hostname ttl\n"); | |
167 | return 0; | |
168 | } | |
169 | item = container_of(h, struct nfs_dns_ent, h); | |
c5b29f88 | 170 | ttl = item->h.expiry_time - seconds_since_boot(); |
e571cbf1 TM |
171 | if (ttl < 0) |
172 | ttl = 0; | |
173 | ||
174 | if (!test_bit(CACHE_NEGATIVE, &h->flags)) { | |
175 | char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1]; | |
176 | ||
177 | rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf)); | |
178 | seq_printf(m, "%15s ", buf); | |
179 | } else | |
180 | seq_puts(m, "<none> "); | |
181 | seq_printf(m, "%15s %ld\n", item->hostname, ttl); | |
182 | return 0; | |
183 | } | |
184 | ||
0a6566ec | 185 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
e571cbf1 TM |
186 | struct nfs_dns_ent *key) |
187 | { | |
188 | struct cache_head *ch; | |
189 | ||
190 | ch = sunrpc_cache_lookup(cd, | |
191 | &key->h, | |
192 | nfs_dns_hash(key)); | |
193 | if (!ch) | |
194 | return NULL; | |
195 | return container_of(ch, struct nfs_dns_ent, h); | |
196 | } | |
197 | ||
0a6566ec | 198 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
e571cbf1 TM |
199 | struct nfs_dns_ent *new, |
200 | struct nfs_dns_ent *key) | |
201 | { | |
202 | struct cache_head *ch; | |
203 | ||
204 | ch = sunrpc_cache_update(cd, | |
205 | &new->h, &key->h, | |
206 | nfs_dns_hash(key)); | |
207 | if (!ch) | |
208 | return NULL; | |
209 | return container_of(ch, struct nfs_dns_ent, h); | |
210 | } | |
211 | ||
212 | static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) | |
213 | { | |
214 | char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; | |
215 | struct nfs_dns_ent key, *item; | |
216 | unsigned long ttl; | |
217 | ssize_t len; | |
218 | int ret = -EINVAL; | |
219 | ||
220 | if (buf[buflen-1] != '\n') | |
221 | goto out; | |
222 | buf[buflen-1] = '\0'; | |
223 | ||
224 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
225 | if (len <= 0) | |
226 | goto out; | |
599ec129 | 227 | key.addrlen = rpc_pton(cd->net, buf1, len, |
e571cbf1 TM |
228 | (struct sockaddr *)&key.addr, |
229 | sizeof(key.addr)); | |
230 | ||
231 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
232 | if (len <= 0) | |
233 | goto out; | |
234 | ||
235 | key.hostname = buf1; | |
236 | key.namelen = len; | |
237 | memset(&key.h, 0, sizeof(key.h)); | |
238 | ||
239 | ttl = get_expiry(&buf); | |
240 | if (ttl == 0) | |
241 | goto out; | |
c5b29f88 | 242 | key.h.expiry_time = ttl + seconds_since_boot(); |
e571cbf1 TM |
243 | |
244 | ret = -ENOMEM; | |
245 | item = nfs_dns_lookup(cd, &key); | |
246 | if (item == NULL) | |
247 | goto out; | |
248 | ||
249 | if (key.addrlen == 0) | |
250 | set_bit(CACHE_NEGATIVE, &key.h.flags); | |
251 | ||
252 | item = nfs_dns_update(cd, &key, item); | |
253 | if (item == NULL) | |
254 | goto out; | |
255 | ||
256 | ret = 0; | |
257 | cache_put(&item->h, cd); | |
258 | out: | |
259 | return ret; | |
260 | } | |
261 | ||
e571cbf1 TM |
262 | static int do_cache_lookup(struct cache_detail *cd, |
263 | struct nfs_dns_ent *key, | |
264 | struct nfs_dns_ent **item, | |
265 | struct nfs_cache_defer_req *dreq) | |
266 | { | |
267 | int ret = -ENOMEM; | |
268 | ||
269 | *item = nfs_dns_lookup(cd, key); | |
270 | if (*item) { | |
271 | ret = cache_check(cd, &(*item)->h, &dreq->req); | |
272 | if (ret) | |
273 | *item = NULL; | |
274 | } | |
275 | return ret; | |
276 | } | |
277 | ||
278 | static int do_cache_lookup_nowait(struct cache_detail *cd, | |
279 | struct nfs_dns_ent *key, | |
280 | struct nfs_dns_ent **item) | |
281 | { | |
282 | int ret = -ENOMEM; | |
283 | ||
284 | *item = nfs_dns_lookup(cd, key); | |
285 | if (!*item) | |
286 | goto out_err; | |
287 | ret = -ETIMEDOUT; | |
288 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) | |
c5b29f88 | 289 | || (*item)->h.expiry_time < seconds_since_boot() |
e571cbf1 TM |
290 | || cd->flush_time > (*item)->h.last_refresh) |
291 | goto out_put; | |
292 | ret = -ENOENT; | |
293 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) | |
294 | goto out_put; | |
295 | return 0; | |
296 | out_put: | |
297 | cache_put(&(*item)->h, cd); | |
298 | out_err: | |
299 | *item = NULL; | |
300 | return ret; | |
301 | } | |
302 | ||
303 | static int do_cache_lookup_wait(struct cache_detail *cd, | |
304 | struct nfs_dns_ent *key, | |
305 | struct nfs_dns_ent **item) | |
306 | { | |
307 | struct nfs_cache_defer_req *dreq; | |
308 | int ret = -ENOMEM; | |
309 | ||
310 | dreq = nfs_cache_defer_req_alloc(); | |
311 | if (!dreq) | |
312 | goto out; | |
313 | ret = do_cache_lookup(cd, key, item, dreq); | |
314 | if (ret == -EAGAIN) { | |
315 | ret = nfs_cache_wait_for_upcall(dreq); | |
316 | if (!ret) | |
317 | ret = do_cache_lookup_nowait(cd, key, item); | |
318 | } | |
319 | nfs_cache_defer_req_put(dreq); | |
320 | out: | |
321 | return ret; | |
322 | } | |
323 | ||
1b340d01 SK |
324 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, |
325 | size_t namelen, struct sockaddr *sa, size_t salen) | |
e571cbf1 TM |
326 | { |
327 | struct nfs_dns_ent key = { | |
328 | .hostname = name, | |
329 | .namelen = namelen, | |
330 | }; | |
331 | struct nfs_dns_ent *item = NULL; | |
332 | ssize_t ret; | |
1b340d01 | 333 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
e571cbf1 | 334 | |
1b340d01 | 335 | ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item); |
e571cbf1 TM |
336 | if (ret == 0) { |
337 | if (salen >= item->addrlen) { | |
338 | memcpy(sa, &item->addr, item->addrlen); | |
339 | ret = item->addrlen; | |
340 | } else | |
341 | ret = -EOVERFLOW; | |
1b340d01 | 342 | cache_put(&item->h, nn->nfs_dns_resolve); |
e571cbf1 TM |
343 | } else if (ret == -ENOENT) |
344 | ret = -ESRCH; | |
345 | return ret; | |
346 | } | |
347 | ||
1b340d01 | 348 | int nfs_dns_resolver_cache_init(struct net *net) |
e571cbf1 | 349 | { |
1b340d01 SK |
350 | int err = -ENOMEM; |
351 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
352 | struct cache_detail *cd; | |
353 | struct cache_head **tbl; | |
354 | ||
355 | cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL); | |
356 | if (cd == NULL) | |
357 | goto err_cd; | |
358 | ||
359 | tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *), | |
360 | GFP_KERNEL); | |
361 | if (tbl == NULL) | |
362 | goto err_tbl; | |
363 | ||
364 | cd->owner = THIS_MODULE, | |
365 | cd->hash_size = NFS_DNS_HASHTBL_SIZE, | |
366 | cd->hash_table = tbl, | |
367 | cd->name = "dns_resolve", | |
368 | cd->cache_put = nfs_dns_ent_put, | |
369 | cd->cache_upcall = nfs_dns_upcall, | |
370 | cd->cache_parse = nfs_dns_parse, | |
371 | cd->cache_show = nfs_dns_show, | |
372 | cd->match = nfs_dns_match, | |
373 | cd->init = nfs_dns_ent_init, | |
374 | cd->update = nfs_dns_ent_update, | |
375 | cd->alloc = nfs_dns_ent_alloc, | |
376 | ||
377 | nfs_cache_init(cd); | |
378 | err = nfs_cache_register_net(net, cd); | |
379 | if (err) | |
380 | goto err_reg; | |
381 | nn->nfs_dns_resolve = cd; | |
382 | return 0; | |
9222b955 | 383 | |
1b340d01 SK |
384 | err_reg: |
385 | nfs_cache_destroy(cd); | |
386 | kfree(cd->hash_table); | |
387 | err_tbl: | |
388 | kfree(cd); | |
389 | err_cd: | |
390 | return err; | |
391 | } | |
392 | ||
393 | void nfs_dns_resolver_cache_destroy(struct net *net) | |
394 | { | |
395 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
396 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
397 | ||
398 | nfs_cache_unregister_net(net, cd); | |
399 | nfs_cache_destroy(cd); | |
400 | kfree(cd->hash_table); | |
401 | kfree(cd); | |
402 | } | |
403 | ||
9df69c81 SK |
404 | static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event, |
405 | void *ptr) | |
406 | { | |
407 | struct super_block *sb = ptr; | |
408 | struct net *net = sb->s_fs_info; | |
409 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
410 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
411 | int ret = 0; | |
412 | ||
413 | if (cd == NULL) | |
414 | return 0; | |
415 | ||
416 | if (!try_module_get(THIS_MODULE)) | |
417 | return 0; | |
418 | ||
419 | switch (event) { | |
420 | case RPC_PIPEFS_MOUNT: | |
421 | ret = nfs_cache_register_sb(sb, cd); | |
422 | break; | |
423 | case RPC_PIPEFS_UMOUNT: | |
424 | nfs_cache_unregister_sb(sb, cd); | |
425 | break; | |
426 | default: | |
427 | ret = -ENOTSUPP; | |
428 | break; | |
429 | } | |
430 | module_put(THIS_MODULE); | |
431 | return ret; | |
432 | } | |
433 | ||
434 | static struct notifier_block nfs_dns_resolver_block = { | |
435 | .notifier_call = rpc_pipefs_event, | |
436 | }; | |
437 | ||
1b340d01 SK |
438 | int nfs_dns_resolver_init(void) |
439 | { | |
9df69c81 | 440 | return rpc_pipefs_notifier_register(&nfs_dns_resolver_block); |
e571cbf1 TM |
441 | } |
442 | ||
443 | void nfs_dns_resolver_destroy(void) | |
444 | { | |
9df69c81 | 445 | rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block); |
e571cbf1 | 446 | } |
c2e8139c | 447 | #endif |