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7d2852b4 AC |
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 | ||
394b8dde EM |
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" | |
7d2852b4 AC |
39 | |
40 | #define DNS_IDTABLE_SIZE 0x2000 | |
394b8dde | 41 | #define DNS_STATTABLE_SIZE 0x10 |
7d2852b4 | 42 | |
1bf29198 AC |
43 | #define DNS_HOST_IPV4 ((char)'4') |
44 | #define DNS_HOST_IPV6 ((char)'6') | |
45 | #define DNS_REVERSE_IPV4 ((char)'R') | |
46 | #define DNS_REVERSE_IPV6 ((char)'S') | |
7d2852b4 | 47 | |
394b8dde EM |
48 | static void submit_dns(uint16_t uid, char type, const char *addr); |
49 | static void submit_dns_stat(uint16_t uid); | |
7d2852b4 | 50 | |
7d2852b4 AC |
51 | struct dnsreq |
52 | { | |
53 | DNSCB callback; | |
54 | void *data; | |
55 | }; | |
56 | ||
394b8dde EM |
57 | struct dnsstatreq |
58 | { | |
59 | DNSLISTCB callback; | |
60 | void *data; | |
61 | }; | |
62 | ||
7d2852b4 | 63 | static struct dnsreq querytable[DNS_IDTABLE_SIZE]; |
394b8dde | 64 | static struct dnsstatreq stattable[DNS_STATTABLE_SIZE]; |
8a26cd19 EM |
65 | rb_dlink_list nameservers; |
66 | ||
7d2852b4 AC |
67 | |
68 | static uint16_t | |
69 | assign_dns_id(void) | |
70 | { | |
71 | static uint16_t id = 1; | |
72 | int loopcnt = 0; | |
73 | while(1) | |
74 | { | |
75 | if(++loopcnt > DNS_IDTABLE_SIZE) | |
76 | return 0; | |
77 | if(id < DNS_IDTABLE_SIZE - 1 || id == 0) | |
78 | id++; | |
79 | else | |
80 | id = 1; | |
81 | if(querytable[id].callback == NULL) | |
82 | break; | |
83 | } | |
84 | return (id); | |
85 | } | |
86 | ||
394b8dde EM |
87 | static uint8_t |
88 | assign_dns_stat_id(void) | |
89 | { | |
90 | static uint8_t id = 1; | |
91 | int loopcnt = 0; | |
92 | while(1) | |
93 | { | |
94 | if(++loopcnt > DNS_STATTABLE_SIZE) | |
95 | return 0; | |
96 | if(id < DNS_STATTABLE_SIZE - 1 || id == 0) | |
97 | id++; | |
98 | else | |
99 | id = 1; | |
100 | if(stattable[id].callback == NULL) | |
101 | break; | |
102 | } | |
103 | return (id); | |
104 | } | |
105 | ||
7d2852b4 AC |
106 | static void |
107 | handle_dns_failure(uint16_t xid) | |
108 | { | |
109 | struct dnsreq *req; | |
110 | ||
111 | req = &querytable[xid]; | |
112 | if(req->callback == NULL) | |
113 | return; | |
114 | ||
115 | req->callback("FAILED", 0, 0, req->data); | |
116 | req->callback = NULL; | |
117 | req->data = NULL; | |
118 | } | |
119 | ||
394b8dde EM |
120 | static void |
121 | handle_dns_stat_failure(uint8_t xid) | |
122 | { | |
123 | struct dnsstatreq *req; | |
124 | const char *err[] = { "Unknown failure" }; | |
125 | ||
126 | req = &stattable[xid]; | |
127 | if(req->callback == NULL) | |
128 | return; | |
129 | ||
130 | req->callback(1, err, 2, req->data); | |
131 | ||
394b8dde EM |
132 | req->callback = NULL; |
133 | req->data = NULL; | |
134 | } | |
135 | ||
7d2852b4 AC |
136 | void |
137 | cancel_lookup(uint16_t xid) | |
138 | { | |
139 | querytable[xid].callback = NULL; | |
140 | querytable[xid].data = NULL; | |
141 | } | |
142 | ||
394b8dde EM |
143 | void |
144 | cancel_dns_stats(uint16_t xid) | |
145 | { | |
394b8dde EM |
146 | stattable[xid].callback = NULL; |
147 | stattable[xid].data = NULL; | |
148 | } | |
149 | ||
7d2852b4 AC |
150 | uint16_t |
151 | lookup_hostname(const char *hostname, int aftype, DNSCB callback, void *data) | |
152 | { | |
153 | struct dnsreq *req; | |
154 | int aft; | |
155 | uint16_t nid; | |
156 | check_authd(); | |
157 | nid = assign_dns_id(); | |
158 | if((nid = assign_dns_id()) == 0) | |
159 | return 0; | |
160 | ||
161 | req = &querytable[nid]; | |
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 | ||
1bf29198 | 173 | submit_dns(nid, aft == 4 ? DNS_HOST_IPV4 : DNS_HOST_IPV6, hostname); |
7d2852b4 AC |
174 | return (nid); |
175 | } | |
176 | ||
177 | uint16_t | |
178 | lookup_ip(const char *addr, int aftype, DNSCB callback, void *data) | |
179 | { | |
180 | struct dnsreq *req; | |
181 | int aft; | |
182 | uint16_t nid; | |
183 | check_authd(); | |
184 | ||
185 | if((nid = assign_dns_id()) == 0) | |
186 | return 0; | |
394b8dde | 187 | |
7d2852b4 AC |
188 | req = &querytable[nid]; |
189 | ||
190 | req->callback = callback; | |
191 | req->data = data; | |
192 | ||
193 | #ifdef RB_IPV6 | |
194 | if(aftype == AF_INET6) | |
195 | aft = 6; | |
196 | else | |
197 | #endif | |
198 | aft = 4; | |
199 | ||
1bf29198 | 200 | submit_dns(nid, aft == 4 ? DNS_REVERSE_IPV4 : DNS_REVERSE_IPV6, addr); |
7d2852b4 AC |
201 | return (nid); |
202 | } | |
203 | ||
394b8dde EM |
204 | uint8_t |
205 | get_nameservers(DNSLISTCB callback, void *data) | |
206 | { | |
207 | struct dnsstatreq *req; | |
208 | uint8_t nid; | |
209 | check_authd(); | |
210 | ||
211 | if((nid = assign_dns_stat_id()) == 0) | |
212 | return 0; | |
213 | ||
214 | req = &stattable[nid]; | |
215 | req->callback = callback; | |
216 | req->data = data; | |
217 | ||
218 | submit_dns_stat(nid); | |
219 | return (nid); | |
220 | } | |
221 | ||
fb7d74ef | 222 | void |
1bf29198 | 223 | dns_results_callback(const char *callid, const char *status, const char *type, const char *results) |
7d2852b4 AC |
224 | { |
225 | struct dnsreq *req; | |
226 | uint16_t nid; | |
227 | int st; | |
228 | int aft; | |
229 | long lnid = strtol(callid, NULL, 16); | |
230 | ||
231 | if(lnid > DNS_IDTABLE_SIZE || lnid == 0) | |
232 | return; | |
233 | nid = (uint16_t)lnid; | |
234 | req = &querytable[nid]; | |
394b8dde | 235 | st = (*status == 'O'); |
1bf29198 | 236 | aft = *type == '6' || *type == 'S' ? 6 : 4; |
7d2852b4 AC |
237 | if(req->callback == NULL) |
238 | { | |
239 | /* got cancelled..oh well */ | |
240 | req->data = NULL; | |
241 | return; | |
242 | } | |
243 | #ifdef RB_IPV6 | |
244 | if(aft == 6) | |
245 | aft = AF_INET6; | |
246 | else | |
247 | #endif | |
248 | aft = AF_INET; | |
249 | ||
250 | req->callback(results, st, aft, req->data); | |
251 | req->callback = NULL; | |
252 | req->data = NULL; | |
253 | } | |
254 | ||
7d2852b4 | 255 | void |
394b8dde | 256 | dns_stats_results_callback(const char *callid, const char *status, int resc, const char *resv[]) |
7d2852b4 | 257 | { |
394b8dde EM |
258 | struct dnsstatreq *req; |
259 | uint8_t nid; | |
260 | int st, i; | |
261 | long lnid = strtol(callid, NULL, 16); | |
262 | ||
263 | if(lnid > DNS_STATTABLE_SIZE || lnid == 0) | |
264 | return; | |
265 | nid = (uint8_t)lnid; | |
266 | req = &stattable[nid]; | |
267 | ||
268 | if(req->callback == NULL) | |
7d2852b4 | 269 | { |
394b8dde EM |
270 | req->data = NULL; |
271 | return; | |
7d2852b4 | 272 | } |
394b8dde EM |
273 | |
274 | switch(*status) | |
275 | { | |
276 | case 'Y': | |
277 | st = 0; | |
278 | break; | |
279 | case 'X': | |
280 | /* Error */ | |
281 | st = 1; | |
282 | break; | |
283 | default: | |
284 | /* Shouldn't happen... */ | |
285 | return; | |
286 | } | |
287 | ||
288 | /* Query complete */ | |
289 | req->callback(resc, resv, st, stattable[nid].data); | |
290 | ||
394b8dde EM |
291 | req->data = NULL; |
292 | req->callback = NULL; | |
293 | } | |
294 | ||
295 | static void | |
8a26cd19 | 296 | get_nameservers_cb(int resc, const char *resv[], int status, void *data) |
394b8dde | 297 | { |
394b8dde EM |
298 | if(status == 0) |
299 | { | |
8a26cd19 EM |
300 | rb_dlink_node *n, *tn; |
301 | ||
302 | RB_DLINK_FOREACH_SAFE(n, tn, nameservers.head) | |
303 | { | |
304 | /* Clean up old nameservers */ | |
305 | rb_free(n->data); | |
306 | rb_dlinkDestroy(n, &nameservers); | |
307 | } | |
308 | ||
394b8dde | 309 | for(int i = 0; i < resc; i++) |
8a26cd19 | 310 | rb_dlinkAddAlloc(rb_strdup(resv[i]), &nameservers); |
394b8dde EM |
311 | } |
312 | else | |
313 | { | |
8a26cd19 | 314 | const char *error = resc ? resv[resc] : "Unknown error"; |
881acf00 | 315 | iwarn("Error getting DNS servers: %s", error); |
394b8dde | 316 | } |
394b8dde EM |
317 | } |
318 | ||
8a26cd19 EM |
319 | void |
320 | init_nameserver_cache(void) | |
321 | { | |
322 | (void)get_nameservers(get_nameservers_cb, NULL); | |
7d2852b4 AC |
323 | } |
324 | ||
7d2852b4 | 325 | static void |
1bf29198 | 326 | submit_dns(uint16_t nid, char type, const char *addr) |
7d2852b4 AC |
327 | { |
328 | if(authd_helper == NULL) | |
329 | { | |
330 | handle_dns_failure(nid); | |
331 | return; | |
332 | } | |
1bf29198 | 333 | rb_helper_write(authd_helper, "D %x %c %s", nid, type, addr); |
7d2852b4 | 334 | } |
394b8dde EM |
335 | |
336 | static void | |
337 | submit_dns_stat(uint16_t nid) | |
338 | { | |
339 | if(authd_helper == NULL) | |
340 | { | |
341 | handle_dns_stat_failure(nid); | |
342 | return; | |
343 | } | |
344 | rb_helper_write(authd_helper, "S %x D", nid); | |
345 | } |