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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 | ||
40 | #define DNS_HOST_IPV4 ((char)'4') | |
41 | #define DNS_HOST_IPV6 ((char)'6') | |
42 | #define DNS_REVERSE_IPV4 ((char)'R') | |
43 | #define DNS_REVERSE_IPV6 ((char)'S') | |
44 | ||
45 | static void submit_dns(uint32_t uid, char type, const char *addr); | |
46 | static void submit_dns_stat(uint32_t uid); | |
47 | ||
48 | struct dnsreq | |
49 | { | |
50 | DNSCB callback; | |
51 | void *data; | |
52 | }; | |
53 | ||
54 | struct dnsstatreq | |
55 | { | |
56 | DNSLISTCB callback; | |
57 | void *data; | |
58 | }; | |
59 | ||
60 | /* These serve as a form of sparse array */ | |
61 | static rb_dictionary *query_dict; | |
62 | static rb_dictionary *stat_dict; | |
63 | ||
64 | rb_dlink_list nameservers; | |
65 | ||
66 | static uint32_t query_id = 0; | |
67 | static uint32_t stat_id = 0; | |
68 | ||
69 | ||
70 | static inline uint32_t | |
71 | assign_id(uint32_t *id) | |
72 | { | |
73 | if(++(*id) == 0) | |
74 | *id = 1; | |
75 | ||
76 | return *id; | |
77 | } | |
78 | ||
79 | static void | |
80 | handle_dns_failure(uint32_t xid) | |
81 | { | |
82 | struct dnsreq *req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(xid)); | |
83 | s_assert(req); | |
84 | ||
85 | if(req->callback == NULL) | |
86 | return; | |
87 | ||
88 | req->callback("FAILED", 0, 0, req->data); | |
89 | req->callback = NULL; | |
90 | req->data = NULL; | |
91 | } | |
92 | ||
93 | static void | |
94 | handle_dns_stat_failure(uint32_t xid) | |
95 | { | |
96 | struct dnsstatreq *req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(xid)); | |
97 | s_assert(req); | |
98 | ||
99 | if(req->callback == NULL) | |
100 | return; | |
101 | ||
102 | req->callback(1, NULL, 2, req->data); | |
103 | req->callback = NULL; | |
104 | req->data = NULL; | |
105 | } | |
106 | ||
107 | ||
108 | void | |
109 | cancel_lookup(uint32_t xid) | |
110 | { | |
111 | struct dnsreq *req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(xid)); | |
112 | s_assert(req); | |
113 | req->callback = NULL; | |
114 | req->data = NULL; | |
115 | } | |
116 | ||
117 | void | |
118 | cancel_dns_stats(uint32_t xid) | |
119 | { | |
120 | struct dnsstatreq *req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(xid)); | |
121 | s_assert(req); | |
122 | req->callback = NULL; | |
123 | req->data = NULL; | |
124 | } | |
125 | ||
126 | ||
127 | uint32_t | |
128 | lookup_hostname(const char *hostname, int aftype, DNSCB callback, void *data) | |
129 | { | |
130 | struct dnsreq *req = rb_malloc(sizeof(struct dnsreq)); | |
131 | int aft; | |
132 | uint32_t rid = assign_id(&query_id); | |
133 | ||
134 | check_authd(); | |
135 | ||
136 | rb_dictionary_add(query_dict, RB_UINT_TO_POINTER(rid), req); | |
137 | ||
138 | req->callback = callback; | |
139 | req->data = data; | |
140 | ||
141 | #ifdef RB_IPV6 | |
142 | if(aftype == AF_INET6) | |
143 | aft = 6; | |
144 | else | |
145 | #endif | |
146 | aft = 4; | |
147 | ||
148 | submit_dns(rid, aft == 4 ? DNS_HOST_IPV4 : DNS_HOST_IPV6, hostname); | |
149 | return (rid); | |
150 | } | |
151 | ||
152 | uint32_t | |
153 | lookup_ip(const char *addr, int aftype, DNSCB callback, void *data) | |
154 | { | |
155 | struct dnsreq *req = rb_malloc(sizeof(struct dnsreq)); | |
156 | int aft; | |
157 | uint32_t rid = assign_id(&query_id); | |
158 | ||
159 | check_authd(); | |
160 | ||
161 | rb_dictionary_add(query_dict, RB_UINT_TO_POINTER(rid), req); | |
162 | ||
163 | req->callback = callback; | |
164 | req->data = data; | |
165 | ||
166 | #ifdef RB_IPV6 | |
167 | if(aftype == AF_INET6) | |
168 | aft = 6; | |
169 | else | |
170 | #endif | |
171 | aft = 4; | |
172 | ||
173 | submit_dns(rid, aft == 4 ? DNS_REVERSE_IPV4 : DNS_REVERSE_IPV6, addr); | |
174 | return (rid); | |
175 | } | |
176 | ||
177 | static uint32_t | |
178 | get_nameservers(DNSLISTCB callback, void *data) | |
179 | { | |
180 | struct dnsstatreq *req = rb_malloc(sizeof(struct dnsstatreq)); | |
181 | uint32_t qid = assign_id(&stat_id); | |
182 | ||
183 | check_authd(); | |
184 | ||
185 | rb_dictionary_add(stat_dict, RB_UINT_TO_POINTER(qid), req); | |
186 | ||
187 | req->callback = callback; | |
188 | req->data = data; | |
189 | ||
190 | submit_dns_stat(qid); | |
191 | return (qid); | |
192 | } | |
193 | ||
194 | ||
195 | void | |
196 | dns_results_callback(const char *callid, const char *status, const char *type, const char *results) | |
197 | { | |
198 | struct dnsreq *req; | |
199 | uint32_t rid; | |
200 | int st; | |
201 | int aft; | |
202 | long lrid = strtol(callid, NULL, 16); | |
203 | ||
204 | if(lrid > UINT32_MAX) | |
205 | return; | |
206 | ||
207 | rid = (uint32_t)lrid; | |
208 | req = rb_dictionary_retrieve(query_dict, RB_UINT_TO_POINTER(rid)); | |
209 | if(req == NULL) | |
210 | return; | |
211 | ||
212 | st = (*status == 'O'); | |
213 | aft = *type == '6' || *type == 'S' ? 6 : 4; | |
214 | if(req->callback == NULL) | |
215 | { | |
216 | /* got cancelled..oh well */ | |
217 | req->data = NULL; | |
218 | return; | |
219 | } | |
220 | #ifdef RB_IPV6 | |
221 | if(aft == 6) | |
222 | aft = AF_INET6; | |
223 | else | |
224 | #endif | |
225 | aft = AF_INET; | |
226 | ||
227 | req->callback(results, st, aft, req->data); | |
228 | ||
229 | rb_free(req); | |
230 | rb_dictionary_delete(query_dict, RB_UINT_TO_POINTER(rid)); | |
231 | } | |
232 | ||
233 | void | |
234 | dns_stats_results_callback(const char *callid, const char *status, int resc, const char *resv[]) | |
235 | { | |
236 | struct dnsstatreq *req; | |
237 | uint32_t qid; | |
238 | int st; | |
239 | long lqid = strtol(callid, NULL, 16); | |
240 | ||
241 | if(lqid > UINT32_MAX) | |
242 | return; | |
243 | ||
244 | qid = (uint32_t)lqid; | |
245 | req = rb_dictionary_retrieve(stat_dict, RB_UINT_TO_POINTER(qid)); | |
246 | ||
247 | s_assert(req); | |
248 | ||
249 | if(req->callback == NULL) | |
250 | { | |
251 | req->data = NULL; | |
252 | return; | |
253 | } | |
254 | ||
255 | switch(*status) | |
256 | { | |
257 | case 'Y': | |
258 | st = 0; | |
259 | break; | |
260 | case 'X': | |
261 | /* Error */ | |
262 | st = 1; | |
263 | break; | |
264 | default: | |
265 | /* Shouldn't happen... */ | |
266 | return; | |
267 | } | |
268 | ||
269 | /* Query complete */ | |
270 | req->callback(resc, resv, st, req->data); | |
271 | ||
272 | rb_free(req); | |
273 | rb_dictionary_delete(stat_dict, RB_UINT_TO_POINTER(qid)); | |
274 | } | |
275 | ||
276 | static void | |
277 | stats_results_callback(int resc, const char *resv[], int status, void *data) | |
278 | { | |
279 | if(status == 0) | |
280 | { | |
281 | rb_dlink_node *n, *tn; | |
282 | ||
283 | RB_DLINK_FOREACH_SAFE(n, tn, nameservers.head) | |
284 | { | |
285 | /* Clean up old nameservers */ | |
286 | rb_free(n->data); | |
287 | rb_dlinkDestroy(n, &nameservers); | |
288 | } | |
289 | ||
290 | for(int i = 0; i < resc; i++) | |
291 | rb_dlinkAddAlloc(rb_strdup(resv[i]), &nameservers); | |
292 | } | |
293 | else | |
294 | { | |
295 | const char *error = resc ? resv[resc] : "Unknown error"; | |
296 | iwarn("Error getting DNS servers: %s", error); | |
297 | } | |
298 | } | |
299 | ||
300 | ||
301 | void | |
302 | init_dns(void) | |
303 | { | |
304 | query_dict = rb_dictionary_create("dns queries", rb_uint32cmp); | |
305 | stat_dict = rb_dictionary_create("dns stat queries", rb_uint32cmp); | |
306 | (void)get_nameservers(stats_results_callback, NULL); | |
307 | } | |
308 | ||
309 | void | |
310 | reload_nameservers(void) | |
311 | { | |
312 | check_authd(); | |
313 | rb_helper_write(authd_helper, "R D"); | |
314 | (void)get_nameservers(stats_results_callback, NULL); | |
315 | } | |
316 | ||
317 | ||
318 | static void | |
319 | submit_dns(uint32_t nid, char type, const char *addr) | |
320 | { | |
321 | if(authd_helper == NULL) | |
322 | { | |
323 | handle_dns_failure(nid); | |
324 | return; | |
325 | } | |
326 | rb_helper_write(authd_helper, "D %x %c %s", nid, type, addr); | |
327 | } | |
328 | ||
329 | static void | |
330 | submit_dns_stat(uint32_t nid) | |
331 | { | |
332 | if(authd_helper == NULL) | |
333 | { | |
334 | handle_dns_stat_failure(nid); | |
335 | return; | |
336 | } | |
337 | rb_helper_write(authd_helper, "S %x D", nid); | |
338 | } |