1/*
2   Unix SMB/CIFS implementation.
3
4   NetBIOS name cache module on top of gencache mechanism.
5
6   Copyright (C) Tim Potter         2002
7   Copyright (C) Rafal Szczesniak   2002
8   Copyright (C) Jeremy Allison     2007
9
10   This program is free software; you can redistribute it and/or modify
11   it under the terms of the GNU General Public License as published by
12   the Free Software Foundation; either version 3 of the License, or
13   (at your option) any later version.
14
15   This program is distributed in the hope that it will be useful,
16   but WITHOUT ANY WARRANTY; without even the implied warranty of
17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18   GNU General Public License for more details.
19
20   You should have received a copy of the GNU General Public License
21   along with this program.  If not, see <http://www.gnu.org/licenses/>.
22*/
23
24#include "includes.h"
25
26#define NBTKEY_FMT  "NBT/%s#%02X"
27
28/**
29 * Initialise namecache system. Function calls gencache
30 * initialisation function to perform necessary actions
31 *
32 * @return true upon successful initialisation of the cache or
33 *         false on failure
34 **/
35
36bool namecache_enable(void)
37{
38	/*
39	 * Check if name caching disabled by setting the name cache
40	 * timeout to zero.
41	 */
42
43	if (lp_name_cache_timeout() == 0) {
44		DEBUG(5, ("namecache_enable: disabling netbios name cache\n"));
45		return False;
46	}
47
48	/* I leave it for now, though I don't think we really
49	 * need this (mimir, 27.09.2002) */
50	DEBUG(5, ("namecache_enable: enabling netbios namecache, timeout %d "
51		  "seconds\n", lp_name_cache_timeout()));
52
53	return True;
54}
55
56/**
57 * Generates a key for netbios name lookups on basis of
58 * netbios name and type.
59 * The caller must free returned key string when finished.
60 *
61 * @param name netbios name string (case insensitive)
62 * @param name_type netbios type of the name being looked up
63 *
64 * @return string consisted of uppercased name and appended
65 *         type number
66 */
67
68static char* namecache_key(const char *name,
69				int name_type)
70{
71	char *keystr;
72	asprintf_strupper_m(&keystr, NBTKEY_FMT, name, name_type);
73
74	return keystr;
75}
76
77/**
78 * Store a name(s) in the name cache
79 *
80 * @param name netbios names array
81 * @param name_type integer netbios name type
82 * @param num_names number of names being stored
83 * @param ip_list array of in_addr structures containing
84 *        ip addresses being stored
85 **/
86
87bool namecache_store(const char *name,
88			int name_type,
89			int num_names,
90			struct ip_service *ip_list)
91{
92	time_t expiry;
93	char *key, *value_string;
94	int i;
95	bool ret;
96
97	if (name_type > 255) {
98		return False; /* Don't store non-real name types. */
99	}
100
101	if ( DEBUGLEVEL >= 5 ) {
102		TALLOC_CTX *ctx = talloc_stackframe();
103		char *addr = NULL;
104
105		DEBUG(5, ("namecache_store: storing %d address%s for %s#%02x: ",
106			num_names, num_names == 1 ? "": "es", name, name_type));
107
108		for (i = 0; i < num_names; i++) {
109			addr = print_canonical_sockaddr(ctx,
110							&ip_list[i].ss);
111			if (!addr) {
112				continue;
113			}
114			DEBUGADD(5, ("%s%s", addr,
115				(i == (num_names - 1) ? "" : ",")));
116
117		}
118		DEBUGADD(5, ("\n"));
119		TALLOC_FREE(ctx);
120	}
121
122	key = namecache_key(name, name_type);
123	if (!key) {
124		return False;
125	}
126
127	expiry = time(NULL) + lp_name_cache_timeout();
128
129	/*
130	 * Generate string representation of ip addresses list
131	 * First, store the number of ip addresses and then
132	 * place each single ip
133	 */
134	if (!ipstr_list_make(&value_string, ip_list, num_names)) {
135		SAFE_FREE(key);
136		SAFE_FREE(value_string);
137		return false;
138	}
139
140	/* set the entry */
141	ret = gencache_set(key, value_string, expiry);
142	SAFE_FREE(key);
143	SAFE_FREE(value_string);
144	return ret;
145}
146
147/**
148 * Look up a name in the cache.
149 *
150 * @param name netbios name to look up for
151 * @param name_type netbios name type of @param name
152 * @param ip_list mallocated list of IP addresses if found in the cache,
153 *        NULL otherwise
154 * @param num_names number of entries found
155 *
156 * @return true upon successful fetch or
157 *         false if name isn't found in the cache or has expired
158 **/
159
160bool namecache_fetch(const char *name,
161			int name_type,
162			struct ip_service **ip_list,
163			int *num_names)
164{
165	char *key, *value;
166	time_t timeout;
167
168	/* exit now if null pointers were passed as they're required further */
169	if (!ip_list || !num_names) {
170		return False;
171	}
172
173	if (name_type > 255) {
174		return False; /* Don't fetch non-real name types. */
175	}
176
177	*num_names = 0;
178
179	/*
180	 * Use gencache interface - lookup the key
181	 */
182	key = namecache_key(name, name_type);
183	if (!key) {
184		return False;
185	}
186
187	if (!gencache_get(key, &value, &timeout)) {
188		DEBUG(5, ("no entry for %s#%02X found.\n", name, name_type));
189		SAFE_FREE(key);
190		return False;
191	} else {
192		DEBUG(5, ("name %s#%02X found.\n", name, name_type));
193	}
194
195	/*
196	 * Split up the stored value into the list of IP adresses
197	 */
198	*num_names = ipstr_list_parse(value, ip_list);
199
200	SAFE_FREE(key);
201	SAFE_FREE(value);
202
203	return *num_names > 0; /* true only if some ip has been fetched */
204}
205
206/**
207 * Remove a namecache entry. Needed for site support.
208 *
209 **/
210
211bool namecache_delete(const char *name, int name_type)
212{
213	bool ret;
214	char *key;
215
216	if (name_type > 255) {
217		return False; /* Don't fetch non-real name types. */
218	}
219
220	key = namecache_key(name, name_type);
221	if (!key) {
222		return False;
223	}
224	ret = gencache_del(key);
225	SAFE_FREE(key);
226	return ret;
227}
228
229/**
230 * Delete single namecache entry. Look at the
231 * gencache_iterate definition.
232 *
233 **/
234
235static void flush_netbios_name(const char *key,
236			const char *value,
237			time_t timeout,
238			void *dptr)
239{
240	gencache_del(key);
241	DEBUG(5, ("Deleting entry %s\n", key));
242}
243
244/**
245 * Flush all names from the name cache.
246 * It's done by gencache_iterate()
247 *
248 * @return true upon successful deletion or
249 *         false in case of an error
250 **/
251
252void namecache_flush(void)
253{
254	/*
255	 * iterate through each NBT cache's entry and flush it
256	 * by flush_netbios_name function
257	 */
258	gencache_iterate(flush_netbios_name, NULL, "NBT/*");
259	DEBUG(5, ("Namecache flushed\n"));
260}
261
262/* Construct a name status record key. */
263
264static char *namecache_status_record_key(const char *name,
265				int name_type1,
266				int name_type2,
267				const struct sockaddr_storage *keyip)
268{
269	char addr[INET6_ADDRSTRLEN];
270	char *keystr;
271
272	print_sockaddr(addr, sizeof(addr), keyip);
273	asprintf_strupper_m(&keystr, "NBT/%s#%02X.%02X.%s", name,
274			    name_type1, name_type2, addr);
275	return keystr;
276}
277
278/* Store a name status record. */
279
280bool namecache_status_store(const char *keyname, int keyname_type,
281		int name_type, const struct sockaddr_storage *keyip,
282		const char *srvname)
283{
284	char *key;
285	time_t expiry;
286	bool ret;
287
288	key = namecache_status_record_key(keyname, keyname_type,
289			name_type, keyip);
290	if (!key)
291		return False;
292
293	expiry = time(NULL) + lp_name_cache_timeout();
294	ret = gencache_set(key, srvname, expiry);
295
296	if (ret) {
297		DEBUG(5, ("namecache_status_store: entry %s -> %s\n",
298					key, srvname ));
299	} else {
300		DEBUG(5, ("namecache_status_store: entry %s store failed.\n",
301					key ));
302	}
303
304	SAFE_FREE(key);
305	return ret;
306}
307
308/* Fetch a name status record. */
309
310bool namecache_status_fetch(const char *keyname,
311				int keyname_type,
312				int name_type,
313				const struct sockaddr_storage *keyip,
314				char *srvname_out)
315{
316	char *key = NULL;
317	char *value = NULL;
318	time_t timeout;
319
320	key = namecache_status_record_key(keyname, keyname_type,
321			name_type, keyip);
322	if (!key)
323		return False;
324
325	if (!gencache_get(key, &value, &timeout)) {
326		DEBUG(5, ("namecache_status_fetch: no entry for %s found.\n",
327					key));
328		SAFE_FREE(key);
329		return False;
330	} else {
331		DEBUG(5, ("namecache_status_fetch: key %s -> %s\n",
332					key, value ));
333	}
334
335	strlcpy(srvname_out, value, 16);
336	SAFE_FREE(key);
337	SAFE_FREE(value);
338	return True;
339}
340