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