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1 | /* | |
2 | * dns.c: An interface to the resolver module in authd | |
3 | * (based somewhat on ircd-ratbox dns.c) | |
4 | * | |
5 | * Copyright (C) 2005 Aaron Sethman <androsyn@ratbox.org> | |
6 | * Copyright (C) 2005-2012 ircd-ratbox development team | |
7 | * Copyright (C) 2016 William Pitcock <nenolod@dereferenced.org> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 | |
22 | * USA | |
23 | */ | |
24 | ||
25 | #include "stdinc.h" | |
26 | #include "rb_lib.h" | |
27 | #include "client.h" | |
28 | #include "ircd_defs.h" | |
29 | #include "parse.h" | |
30 | #include "dns.h" | |
31 | #include "match.h" | |
32 | #include "logger.h" | |
33 | #include "s_conf.h" | |
34 | #include "client.h" | |
35 | #include "send.h" | |
36 | #include "numeric.h" | |
37 | #include "msg.h" | |
38 | #include "hash.h" | |
39 | #include "s_assert.h" | |
40 | ||
41 | #define DNS_HOST_IPV4 ((char)'4') | |
42 | #define DNS_HOST_IPV6 ((char)'6') | |
43 | #define DNS_REVERSE_IPV4 ((char)'R') | |
44 | #define DNS_REVERSE_IPV6 ((char)'S') | |
45 | ||
46 | static void submit_dns(uint32_t uid, char type, const char *addr); | |
47 | static void submit_dns_stat(uint32_t uid); | |
48 | ||
49 | struct dnsreq | |
50 | { | |
51 | DNSCB callback; | |
52 | void *data; | |
53 | }; | |
54 | ||
55 | struct dnsstatreq | |
56 | { | |
57 | DNSLISTCB callback; | |
58 | void *data; | |
59 | }; | |
60 | ||
61 | /* These serve as a form of sparse array */ | |
62 | static rb_dictionary *query_dict; | |
63 | static rb_dictionary *stat_dict; | |
64 | ||
65 | rb_dlink_list nameservers; | |
66 | ||
67 | static uint32_t query_id = 0; | |
68 | static uint32_t stat_id = 0; | |
69 | ||
70 | ||
71 | static inline uint32_t | |
72 | assign_id(uint32_t *id) | |
73 | { | |
74 | if(++(*id) == 0) | |
75 | *id = 1; | |
76 | ||
77 | return *id; | |
78 | } | |
79 | ||
80 | static void | |
81 | handle_dns_failure(uint32_t xid) | |
82 | { | |
83 | struct dnsreq *req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(xid)); | |
84 | s_assert(req); | |
85 | ||
86 | if(req == NULL || req->callback == NULL) | |
87 | return; | |
88 | ||
89 | req->callback("FAILED", 0, 0, req->data); | |
90 | req->callback = NULL; | |
91 | req->data = NULL; | |
92 | } | |
93 | ||
94 | static void | |
95 | handle_dns_stat_failure(uint32_t xid) | |
96 | { | |
97 | struct dnsstatreq *req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(xid)); | |
98 | s_assert(req); | |
99 | ||
100 | if(req == NULL || req->callback == NULL) | |
101 | return; | |
102 | ||
103 | req->callback(1, NULL, 2, req->data); | |
104 | req->callback = NULL; | |
105 | req->data = NULL; | |
106 | } | |
107 | ||
108 | ||
109 | void | |
110 | cancel_lookup(uint32_t xid) | |
111 | { | |
112 | struct dnsreq *req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(xid)); | |
113 | s_assert(req); | |
114 | ||
115 | if (req == NULL) | |
116 | return; | |
117 | ||
118 | req->callback = NULL; | |
119 | req->data = NULL; | |
120 | } | |
121 | ||
122 | void | |
123 | cancel_dns_stats(uint32_t xid) | |
124 | { | |
125 | struct dnsstatreq *req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(xid)); | |
126 | s_assert(req); | |
127 | ||
128 | if (req == NULL) | |
129 | return; | |
130 | ||
131 | req->callback = NULL; | |
132 | req->data = NULL; | |
133 | } | |
134 | ||
135 | ||
136 | uint32_t | |
137 | lookup_hostname(const char *hostname, int aftype, DNSCB callback, void *data) | |
138 | { | |
139 | struct dnsreq *req = rb_malloc(sizeof(struct dnsreq)); | |
140 | int aft; | |
141 | uint32_t rid = assign_id(&query_id); | |
142 | ||
143 | check_authd(); | |
144 | ||
145 | rb_dictionary_add(query_dict, RB_UINT_TO_POINTER(rid), req); | |
146 | ||
147 | req->callback = callback; | |
148 | req->data = data; | |
149 | ||
150 | if(aftype == AF_INET6) | |
151 | aft = 6; | |
152 | else | |
153 | aft = 4; | |
154 | ||
155 | submit_dns(rid, aft == 4 ? DNS_HOST_IPV4 : DNS_HOST_IPV6, hostname); | |
156 | return (rid); | |
157 | } | |
158 | ||
159 | uint32_t | |
160 | lookup_ip(const char *addr, int aftype, DNSCB callback, void *data) | |
161 | { | |
162 | struct dnsreq *req = rb_malloc(sizeof(struct dnsreq)); | |
163 | int aft; | |
164 | uint32_t rid = assign_id(&query_id); | |
165 | ||
166 | check_authd(); | |
167 | ||
168 | rb_dictionary_add(query_dict, RB_UINT_TO_POINTER(rid), req); | |
169 | ||
170 | req->callback = callback; | |
171 | req->data = data; | |
172 | ||
173 | if(aftype == AF_INET6) | |
174 | aft = 6; | |
175 | else | |
176 | aft = 4; | |
177 | ||
178 | submit_dns(rid, aft == 4 ? DNS_REVERSE_IPV4 : DNS_REVERSE_IPV6, addr); | |
179 | return (rid); | |
180 | } | |
181 | ||
182 | static uint32_t | |
183 | get_nameservers(DNSLISTCB callback, void *data) | |
184 | { | |
185 | struct dnsstatreq *req = rb_malloc(sizeof(struct dnsstatreq)); | |
186 | uint32_t qid = assign_id(&stat_id); | |
187 | ||
188 | check_authd(); | |
189 | ||
190 | rb_dictionary_add(stat_dict, RB_UINT_TO_POINTER(qid), req); | |
191 | ||
192 | req->callback = callback; | |
193 | req->data = data; | |
194 | ||
195 | submit_dns_stat(qid); | |
196 | return (qid); | |
197 | } | |
198 | ||
199 | ||
200 | void | |
201 | dns_results_callback(const char *callid, const char *status, const char *type, const char *results) | |
202 | { | |
203 | struct dnsreq *req; | |
204 | uint32_t rid; | |
205 | int st; | |
206 | int aft; | |
207 | long lrid = strtol(callid, NULL, 16); | |
208 | ||
209 | if(lrid > UINT32_MAX) | |
210 | return; | |
211 | ||
212 | rid = (uint32_t)lrid; | |
213 | req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(rid)); | |
214 | if(req == NULL) | |
215 | return; | |
216 | ||
217 | st = (*status == 'O'); | |
218 | aft = *type == '6' || *type == 'S' ? 6 : 4; | |
219 | if(req->callback == NULL) | |
220 | { | |
221 | /* got cancelled..oh well */ | |
222 | req->data = NULL; | |
223 | return; | |
224 | } | |
225 | if(aft == 6) | |
226 | aft = AF_INET6; | |
227 | else | |
228 | aft = AF_INET; | |
229 | ||
230 | req->callback(results, st, aft, req->data); | |
231 | ||
232 | rb_free(req); | |
233 | rb_dictionary_delete(query_dict, RB_UINT_TO_POINTER(rid)); | |
234 | } | |
235 | ||
236 | void | |
237 | dns_stats_results_callback(const char *callid, const char *status, int resc, const char *resv[]) | |
238 | { | |
239 | struct dnsstatreq *req; | |
240 | uint32_t qid; | |
241 | int st; | |
242 | long lqid = strtol(callid, NULL, 16); | |
243 | ||
244 | if(lqid > UINT32_MAX) | |
245 | return; | |
246 | ||
247 | qid = (uint32_t)lqid; | |
248 | req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(qid)); | |
249 | ||
250 | s_assert(req); | |
251 | if (req == NULL) | |
252 | return; | |
253 | ||
254 | if(req->callback == NULL) | |
255 | { | |
256 | req->data = NULL; | |
257 | return; | |
258 | } | |
259 | ||
260 | switch(*status) | |
261 | { | |
262 | case 'Y': | |
263 | st = 0; | |
264 | break; | |
265 | case 'X': | |
266 | /* Error */ | |
267 | st = 1; | |
268 | break; | |
269 | default: | |
270 | /* Shouldn't happen... */ | |
271 | return; | |
272 | } | |
273 | ||
274 | /* Query complete */ | |
275 | req->callback(resc, resv, st, req->data); | |
276 | ||
277 | rb_free(req); | |
278 | rb_dictionary_delete(stat_dict, RB_UINT_TO_POINTER(qid)); | |
279 | } | |
280 | ||
281 | static void | |
282 | stats_results_callback(int resc, const char *resv[], int status, void *data) | |
283 | { | |
284 | if(status == 0) | |
285 | { | |
286 | rb_dlink_node *n, *tn; | |
287 | ||
288 | RB_DLINK_FOREACH_SAFE(n, tn, nameservers.head) | |
289 | { | |
290 | /* Clean up old nameservers */ | |
291 | rb_free(n->data); | |
292 | rb_dlinkDestroy(n, &nameservers); | |
293 | } | |
294 | ||
295 | for(int i = 0; i < resc; i++) | |
296 | rb_dlinkAddAlloc(rb_strdup(resv[i]), &nameservers); | |
297 | } | |
298 | else | |
299 | { | |
300 | const char *error = resc ? resv[resc - 1] : "Unknown error"; | |
301 | iwarn("Error getting DNS servers: %s", error); | |
302 | } | |
303 | } | |
304 | ||
305 | ||
306 | void | |
307 | init_dns(void) | |
308 | { | |
309 | query_dict = rb_dictionary_create("dns queries", rb_uint32cmp); | |
310 | stat_dict = rb_dictionary_create("dns stat queries", rb_uint32cmp); | |
311 | (void)get_nameservers(stats_results_callback, NULL); | |
312 | } | |
313 | ||
314 | void | |
315 | reload_nameservers(void) | |
316 | { | |
317 | check_authd(); | |
318 | rb_helper_write(authd_helper, "R D"); | |
319 | (void)get_nameservers(stats_results_callback, NULL); | |
320 | } | |
321 | ||
322 | ||
323 | static void | |
324 | submit_dns(uint32_t nid, char type, const char *addr) | |
325 | { | |
326 | if(authd_helper == NULL) | |
327 | { | |
328 | handle_dns_failure(nid); | |
329 | return; | |
330 | } | |
331 | rb_helper_write(authd_helper, "D %x %c %s", nid, type, addr); | |
332 | } | |
333 | ||
334 | static void | |
335 | submit_dns_stat(uint32_t nid) | |
336 | { | |
337 | if(authd_helper == NULL) | |
338 | { | |
339 | handle_dns_stat_failure(nid); | |
340 | return; | |
341 | } | |
342 | rb_helper_write(authd_helper, "S %x D", nid); | |
343 | } |