1 : /* $Id: evdns.c 6979 2006-08-04 18:31:13Z nickm $ */
2 :
3 : /* The original version of this module was written by Adam Langley; for
4 : * a history of modifications, check out the subversion logs.
5 : *
6 : * When editing this module, try to keep it re-mergeable by Adam. Don't
7 : * reformat the whitespace, add Tor dependencies, or so on.
8 : *
9 : * TODO:
10 : * - Support IPv6 and PTR records.
11 : * - Replace all externally visible magic numbers with #defined constants.
12 : * - Write doccumentation for APIs of all external functions.
13 : */
14 :
15 : /* Async DNS Library
16 : * Adam Langley <agl@imperialviolet.org>
17 : * http://www.imperialviolet.org/eventdns.html
18 : * Public Domain code
19 : *
20 : * This software is Public Domain. To view a copy of the public domain dedication,
21 : * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
22 : * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
23 : *
24 : * I ask and expect, but do not require, that all derivative works contain an
25 : * attribution similar to:
26 : * Parts developed by Adam Langley <agl@imperialviolet.org>
27 : *
28 : * You may wish to replace the word "Parts" with something else depending on
29 : * the amount of original code.
30 : *
31 : * (Derivative works does not include programs which link against, run or include
32 : * the source verbatim in their source distributions)
33 : *
34 : * Version: 0.1b
35 : */
36 :
37 : #include <sys/types.h>
38 : #ifdef HAVE_CONFIG_H
39 : #include "config.h"
40 : #endif
41 :
42 : #ifdef DNS_USE_FTIME_FOR_ID
43 : #include <sys/timeb.h>
44 : #endif
45 :
46 : #ifndef DNS_USE_CPU_CLOCK_FOR_ID
47 : #ifndef DNS_USE_GETTIMEOFDAY_FOR_ID
48 : #ifndef DNS_USE_OPENSSL_FOR_ID
49 : #ifndef DNS_USE_FTIME_FOR_ID
50 : #error Must configure at least one id generation method.
51 : #error Please see the documentation.
52 : #endif
53 : #endif
54 : #endif
55 : #endif
56 :
57 : /* #define _POSIX_C_SOURCE 200507 */
58 : #define _GNU_SOURCE
59 :
60 : #ifdef DNS_USE_CPU_CLOCK_FOR_ID
61 : #ifdef DNS_USE_OPENSSL_FOR_ID
62 : #error Multiple id options selected
63 : #endif
64 : #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
65 : #error Multiple id options selected
66 : #endif
67 : #include <time.h>
68 : #endif
69 :
70 : #ifdef DNS_USE_OPENSSL_FOR_ID
71 : #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
72 : #error Multiple id options selected
73 : #endif
74 : #include <openssl/rand.h>
75 : #endif
76 :
77 : #define _FORTIFY_SOURCE 3
78 :
79 : #include <string.h>
80 : #include <fcntl.h>
81 : #ifdef HAVE_SYS_TIME_H
82 : #include <sys/time.h>
83 : #endif
84 : #ifdef HAVE_STDINT_H
85 : #include <stdint.h>
86 : #endif
87 : #include <stdlib.h>
88 : #include <string.h>
89 : #include <errno.h>
90 : #include <assert.h>
91 : #ifdef HAVE_UNISTD_H
92 : #include <unistd.h>
93 : #endif
94 : #include <limits.h>
95 : #include <sys/stat.h>
96 : #include <ctype.h>
97 : #include <stdio.h>
98 : #include <stdarg.h>
99 :
100 : #include "evdns.h"
101 : #include "evutil.h"
102 : #include "log.h"
103 : #ifdef WIN32
104 : #include <winsock2.h>
105 : #include <windows.h>
106 : #include <iphlpapi.h>
107 : #include <io.h>
108 : #else
109 : #include <sys/socket.h>
110 : #include <netinet/in.h>
111 : #include <arpa/inet.h>
112 : #endif
113 :
114 : #ifdef HAVE_NETINET_IN6_H
115 : #include <netinet/in6.h>
116 : #endif
117 :
118 : #define EVDNS_LOG_DEBUG 0
119 : #define EVDNS_LOG_WARN 1
120 :
121 : #ifndef HOST_NAME_MAX
122 : #define HOST_NAME_MAX 255
123 : #endif
124 :
125 : #include <stdio.h>
126 :
127 : #undef MIN
128 : #define MIN(a,b) ((a)<(b)?(a):(b))
129 :
130 : #ifdef __USE_ISOC99B
131 : /* libevent doesn't work without this */
132 : typedef ev_uint8_t u_char;
133 : typedef unsigned int uint;
134 : #endif
135 : #include <event.h>
136 :
137 : #define u64 ev_uint64_t
138 : #define u32 ev_uint32_t
139 : #define u16 ev_uint16_t
140 : #define u8 ev_uint8_t
141 :
142 : #ifdef WIN32
143 : #define open _open
144 : #define read _read
145 : #define close _close
146 : #define strdup _strdup
147 : #endif
148 :
149 : #define MAX_ADDRS 32 /* maximum number of addresses from a single packet */
150 : /* which we bother recording */
151 :
152 : #define TYPE_A EVDNS_TYPE_A
153 : #define TYPE_CNAME 5
154 : #define TYPE_PTR EVDNS_TYPE_PTR
155 : #define TYPE_AAAA EVDNS_TYPE_AAAA
156 :
157 : #define CLASS_INET EVDNS_CLASS_INET
158 :
159 : struct request {
160 : u8 *request; /* the dns packet data */
161 : unsigned int request_len;
162 : int reissue_count;
163 : int tx_count; /* the number of times that this packet has been sent */
164 : unsigned int request_type; /* TYPE_PTR or TYPE_A */
165 : void *user_pointer; /* the pointer given to us for this request */
166 : evdns_callback_type user_callback;
167 : struct nameserver *ns; /* the server which we last sent it */
168 :
169 : /* elements used by the searching code */
170 : int search_index;
171 : struct search_state *search_state;
172 : char *search_origname; /* needs to be free()ed */
173 : int search_flags;
174 :
175 : /* these objects are kept in a circular list */
176 : struct request *next, *prev;
177 :
178 : struct event timeout_event;
179 :
180 : u16 trans_id; /* the transaction id */
181 : char request_appended; /* true if the request pointer is data which follows this struct */
182 : char transmit_me; /* needs to be transmitted */
183 : };
184 :
185 : #ifndef HAVE_STRUCT_IN6_ADDR
186 : struct in6_addr {
187 : u8 s6_addr[16];
188 : };
189 : #endif
190 :
191 : struct reply {
192 : unsigned int type;
193 : unsigned int have_answer;
194 : union {
195 : struct {
196 : u32 addrcount;
197 : u32 addresses[MAX_ADDRS];
198 : } a;
199 : struct {
200 : u32 addrcount;
201 : struct in6_addr addresses[MAX_ADDRS];
202 : } aaaa;
203 : struct {
204 : char name[HOST_NAME_MAX];
205 : } ptr;
206 : } data;
207 : };
208 :
209 : struct nameserver {
210 : int socket; /* a connected UDP socket */
211 : u32 address;
212 : int failed_times; /* number of times which we have given this server a chance */
213 : int timedout; /* number of times in a row a request has timed out */
214 : struct event event;
215 : /* these objects are kept in a circular list */
216 : struct nameserver *next, *prev;
217 : struct event timeout_event; /* used to keep the timeout for */
218 : /* when we next probe this server. */
219 : /* Valid if state == 0 */
220 : char state; /* zero if we think that this server is down */
221 : char choked; /* true if we have an EAGAIN from this server's socket */
222 : char write_waiting; /* true if we are waiting for EV_WRITE events */
223 : };
224 :
225 : static struct request *req_head = NULL, *req_waiting_head = NULL;
226 : static struct nameserver *server_head = NULL;
227 :
228 : /* Represents a local port where we're listening for DNS requests. Right now, */
229 : /* only UDP is supported. */
230 : struct evdns_server_port {
231 : int socket; /* socket we use to read queries and write replies. */
232 : int refcnt; /* reference count. */
233 : char choked; /* Are we currently blocked from writing? */
234 : char closing; /* Are we trying to close this port, pending writes? */
235 : evdns_request_callback_fn_type user_callback; /* Fn to handle requests */
236 : void *user_data; /* Opaque pointer passed to user_callback */
237 : struct event event; /* Read/write event */
238 : /* circular list of replies that we want to write. */
239 : struct server_request *pending_replies;
240 : };
241 :
242 : /* Represents part of a reply being built. (That is, a single RR.) */
243 : struct server_reply_item {
244 : struct server_reply_item *next; /* next item in sequence. */
245 : char *name; /* name part of the RR */
246 : u16 type : 16; /* The RR type */
247 : u16 class : 16; /* The RR class (usually CLASS_INET) */
248 : u32 ttl; /* The RR TTL */
249 : char is_name; /* True iff data is a label */
250 : u16 datalen; /* Length of data; -1 if data is a label */
251 : void *data; /* The contents of the RR */
252 : };
253 :
254 : /* Represents a request that we've received as a DNS server, and holds */
255 : /* the components of the reply as we're constructing it. */
256 : struct server_request {
257 : /* Pointers to the next and previous entries on the list of replies */
258 : /* that we're waiting to write. Only set if we have tried to respond */
259 : /* and gotten EAGAIN. */
260 : struct server_request *next_pending;
261 : struct server_request *prev_pending;
262 :
263 : u16 trans_id; /* Transaction id. */
264 : struct evdns_server_port *port; /* Which port received this request on? */
265 : struct sockaddr_storage addr; /* Where to send the response */
266 : socklen_t addrlen; /* length of addr */
267 :
268 : int n_answer; /* how many answer RRs have been set? */
269 : int n_authority; /* how many authority RRs have been set? */
270 : int n_additional; /* how many additional RRs have been set? */
271 :
272 : struct server_reply_item *answer; /* linked list of answer RRs */
273 : struct server_reply_item *authority; /* linked list of authority RRs */
274 : struct server_reply_item *additional; /* linked list of additional RRs */
275 :
276 : /* Constructed response. Only set once we're ready to send a reply. */
277 : /* Once this is set, the RR fields are cleared, and no more should be set. */
278 : char *response;
279 : size_t response_len;
280 :
281 : /* Caller-visible fields: flags, questions. */
282 : struct evdns_server_request base;
283 : };
284 :
285 : /* helper macro */
286 : #define OFFSET_OF(st, member) ((off_t) (((char*)&((st*)0)->member)-(char*)0))
287 :
288 : /* Given a pointer to an evdns_server_request, get the corresponding */
289 : /* server_request. */
290 : #define TO_SERVER_REQUEST(base_ptr) \
291 : ((struct server_request*) \
292 : (((char*)(base_ptr) - OFFSET_OF(struct server_request, base))))
293 :
294 : /* The number of good nameservers that we have */
295 : static int global_good_nameservers = 0;
296 :
297 : /* inflight requests are contained in the req_head list */
298 : /* and are actually going out across the network */
299 : static int global_requests_inflight = 0;
300 : /* requests which aren't inflight are in the waiting list */
301 : /* and are counted here */
302 : static int global_requests_waiting = 0;
303 :
304 : static int global_max_requests_inflight = 64;
305 :
306 : static struct timeval global_timeout = {5, 0}; /* 5 seconds */
307 : static int global_max_reissues = 1; /* a reissue occurs when we get some errors from the server */
308 : static int global_max_retransmits = 3; /* number of times we'll retransmit a request which timed out */
309 : /* number of timeouts in a row before we consider this server to be down */
310 : static int global_max_nameserver_timeout = 3;
311 :
312 : /* These are the timeout values for nameservers. If we find a nameserver is down */
313 : /* we try to probe it at intervals as given below. Values are in seconds. */
314 : static const struct timeval global_nameserver_timeouts[] = {{10, 0}, {60, 0}, {300, 0}, {900, 0}, {3600, 0}};
315 : static const int global_nameserver_timeouts_length = sizeof(global_nameserver_timeouts)/sizeof(struct timeval);
316 :
317 : static struct nameserver *nameserver_pick(void);
318 : static void evdns_request_insert(struct request *req, struct request **head);
319 : static void nameserver_ready_callback(int fd, short events, void *arg);
320 : static int evdns_transmit(void);
321 : static int evdns_request_transmit(struct request *req);
322 : static void nameserver_send_probe(struct nameserver *const ns);
323 : static void search_request_finished(struct request *const);
324 : static int search_try_next(struct request *const req);
325 : static int search_request_new(int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg);
326 : static void evdns_requests_pump_waiting_queue(void);
327 : static u16 transaction_id_pick(void);
328 : static struct request *request_new(int type, const char *name, int flags, evdns_callback_type callback, void *ptr);
329 : static void request_submit(struct request *const req);
330 :
331 : static int server_request_free(struct server_request *req);
332 : static void server_request_free_answers(struct server_request *req);
333 : static void server_port_free(struct evdns_server_port *port);
334 : static void server_port_ready_callback(int fd, short events, void *arg);
335 :
336 : static int strtoint(const char *const str);
337 :
338 : #ifdef WIN32
339 : static int
340 : last_error(int sock)
341 : {
342 : int optval, optvallen=sizeof(optval);
343 : int err = WSAGetLastError();
344 : if (err == WSAEWOULDBLOCK && sock >= 0) {
345 : if (getsockopt(sock, SOL_SOCKET, SO_ERROR, (void*)&optval,
346 : &optvallen))
347 : return err;
348 : if (optval)
349 : return optval;
350 : }
351 : return err;
352 :
353 : }
354 : static int
355 : error_is_eagain(int err)
356 : {
357 : return err == EAGAIN || err == WSAEWOULDBLOCK;
358 : }
359 : static int
360 : inet_aton(const char *c, struct in_addr *addr)
361 : {
362 : ev_uint32_t r;
363 : if (strcmp(c, "255.255.255.255") == 0) {
364 : addr->s_addr = 0xffffffffu;
365 : } else {
366 : r = inet_addr(c);
367 : if (r == INADDR_NONE)
368 : return 0;
369 : addr->s_addr = r;
370 : }
371 : return 1;
372 : }
373 : #else
374 : #define last_error(sock) (errno)
375 : #define error_is_eagain(err) ((err) == EAGAIN)
376 : #endif
377 : #define CLOSE_SOCKET(s) EVUTIL_CLOSESOCKET(s)
378 :
379 : #define ISSPACE(c) isspace((int)(unsigned char)(c))
380 : #define ISDIGIT(c) isdigit((int)(unsigned char)(c))
381 :
382 : static const char *
383 0 : debug_ntoa(u32 address)
384 : {
385 : static char buf[32];
386 0 : u32 a = ntohl(address);
387 0 : evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
388 0 : (int)(u8)((a>>24)&0xff),
389 0 : (int)(u8)((a>>16)&0xff),
390 0 : (int)(u8)((a>>8 )&0xff),
391 0 : (int)(u8)((a )&0xff));
392 0 : return buf;
393 : }
394 :
395 : static evdns_debug_log_fn_type evdns_log_fn = NULL;
396 :
397 : void
398 0 : evdns_set_log_fn(evdns_debug_log_fn_type fn)
399 : {
400 0 : evdns_log_fn = fn;
401 0 : }
402 :
403 : #ifdef __GNUC__
404 : #define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3)))
405 : #else
406 : #define EVDNS_LOG_CHECK
407 : #endif
408 :
409 : static void _evdns_log(int warn, const char *fmt, ...) EVDNS_LOG_CHECK;
410 : static void
411 0 : _evdns_log(int warn, const char *fmt, ...)
412 : {
413 : va_list args;
414 : static char buf[512];
415 0 : if (!evdns_log_fn)
416 0 : return;
417 0 : va_start(args,fmt);
418 0 : evutil_vsnprintf(buf, sizeof(buf), fmt, args);
419 0 : buf[sizeof(buf)-1] = '\0';
420 0 : evdns_log_fn(warn, buf);
421 0 : va_end(args);
422 : }
423 :
424 : #define log _evdns_log
425 :
426 : /* This walks the list of inflight requests to find the */
427 : /* one with a matching transaction id. Returns NULL on */
428 : /* failure */
429 : static struct request *
430 0 : request_find_from_trans_id(u16 trans_id) {
431 0 : struct request *req = req_head, *const started_at = req_head;
432 :
433 0 : if (req) {
434 : do {
435 0 : if (req->trans_id == trans_id) return req;
436 0 : req = req->next;
437 0 : } while (req != started_at);
438 : }
439 :
440 0 : return NULL;
441 : }
442 :
443 : /* a libevent callback function which is called when a nameserver */
444 : /* has gone down and we want to test if it has came back to life yet */
445 : static void
446 0 : nameserver_prod_callback(int fd, short events, void *arg) {
447 0 : struct nameserver *const ns = (struct nameserver *) arg;
448 : (void)fd;
449 : (void)events;
450 :
451 0 : nameserver_send_probe(ns);
452 0 : }
453 :
454 : /* a libevent callback which is called when a nameserver probe (to see if */
455 : /* it has come back to life) times out. We increment the count of failed_times */
456 : /* and wait longer to send the next probe packet. */
457 : static void
458 0 : nameserver_probe_failed(struct nameserver *const ns) {
459 : const struct timeval * timeout;
460 0 : (void) evtimer_del(&ns->timeout_event);
461 0 : if (ns->state == 1) {
462 : /* This can happen if the nameserver acts in a way which makes us mark */
463 : /* it as bad and then starts sending good replies. */
464 0 : return;
465 : }
466 :
467 0 : timeout =
468 0 : &global_nameserver_timeouts[MIN(ns->failed_times,
469 : global_nameserver_timeouts_length - 1)];
470 0 : ns->failed_times++;
471 :
472 0 : evtimer_set(&ns->timeout_event, nameserver_prod_callback, ns);
473 0 : if (evtimer_add(&ns->timeout_event, (struct timeval *) timeout) < 0) {
474 0 : log(EVDNS_LOG_WARN,
475 : "Error from libevent when adding timer event for %s",
476 : debug_ntoa(ns->address));
477 : /* ???? Do more? */
478 : }
479 : }
480 :
481 : /* called when a nameserver has been deemed to have failed. For example, too */
482 : /* many packets have timed out etc */
483 : static void
484 0 : nameserver_failed(struct nameserver *const ns, const char *msg) {
485 : struct request *req, *started_at;
486 : /* if this nameserver has already been marked as failed */
487 : /* then don't do anything */
488 0 : if (!ns->state) return;
489 :
490 0 : log(EVDNS_LOG_WARN, "Nameserver %s has failed: %s",
491 : debug_ntoa(ns->address), msg);
492 0 : global_good_nameservers--;
493 0 : assert(global_good_nameservers >= 0);
494 0 : if (global_good_nameservers == 0) {
495 0 : log(EVDNS_LOG_WARN, "All nameservers have failed");
496 : }
497 :
498 0 : ns->state = 0;
499 0 : ns->failed_times = 1;
500 :
501 0 : evtimer_set(&ns->timeout_event, nameserver_prod_callback, ns);
502 0 : if (evtimer_add(&ns->timeout_event, (struct timeval *) &global_nameserver_timeouts[0]) < 0) {
503 0 : log(EVDNS_LOG_WARN,
504 : "Error from libevent when adding timer event for %s",
505 : debug_ntoa(ns->address));
506 : /* ???? Do more? */
507 : }
508 :
509 : /* walk the list of inflight requests to see if any can be reassigned to */
510 : /* a different server. Requests in the waiting queue don't have a */
511 : /* nameserver assigned yet */
512 :
513 : /* if we don't have *any* good nameservers then there's no point */
514 : /* trying to reassign requests to one */
515 0 : if (!global_good_nameservers) return;
516 :
517 0 : req = req_head;
518 0 : started_at = req_head;
519 0 : if (req) {
520 : do {
521 0 : if (req->tx_count == 0 && req->ns == ns) {
522 : /* still waiting to go out, can be moved */
523 : /* to another server */
524 0 : req->ns = nameserver_pick();
525 : }
526 0 : req = req->next;
527 0 : } while (req != started_at);
528 : }
529 : }
530 :
531 : static void
532 0 : nameserver_up(struct nameserver *const ns) {
533 0 : if (ns->state) return;
534 0 : log(EVDNS_LOG_WARN, "Nameserver %s is back up",
535 : debug_ntoa(ns->address));
536 0 : evtimer_del(&ns->timeout_event);
537 0 : ns->state = 1;
538 0 : ns->failed_times = 0;
539 0 : ns->timedout = 0;
540 0 : global_good_nameservers++;
541 : }
542 :
543 : static void
544 0 : request_trans_id_set(struct request *const req, const u16 trans_id) {
545 0 : req->trans_id = trans_id;
546 0 : *((u16 *) req->request) = htons(trans_id);
547 0 : }
548 :
549 : /* Called to remove a request from a list and dealloc it. */
550 : /* head is a pointer to the head of the list it should be */
551 : /* removed from or NULL if the request isn't in a list. */
552 : static void
553 0 : request_finished(struct request *const req, struct request **head) {
554 0 : if (head) {
555 0 : if (req->next == req) {
556 : /* only item in the list */
557 0 : *head = NULL;
558 : } else {
559 0 : req->next->prev = req->prev;
560 0 : req->prev->next = req->next;
561 0 : if (*head == req) *head = req->next;
562 : }
563 : }
564 :
565 0 : log(EVDNS_LOG_DEBUG, "Removing timeout for request %lx",
566 : (unsigned long) req);
567 0 : evtimer_del(&req->timeout_event);
568 :
569 0 : search_request_finished(req);
570 0 : global_requests_inflight--;
571 :
572 0 : if (!req->request_appended) {
573 : /* need to free the request data on it's own */
574 0 : free(req->request);
575 : } else {
576 : /* the request data is appended onto the header */
577 : /* so everything gets free()ed when we: */
578 : }
579 :
580 0 : free(req);
581 :
582 0 : evdns_requests_pump_waiting_queue();
583 0 : }
584 :
585 : /* This is called when a server returns a funny error code. */
586 : /* We try the request again with another server. */
587 : /* */
588 : /* return: */
589 : /* 0 ok */
590 : /* 1 failed/reissue is pointless */
591 : static int
592 0 : request_reissue(struct request *req) {
593 0 : const struct nameserver *const last_ns = req->ns;
594 : /* the last nameserver should have been marked as failing */
595 : /* by the caller of this function, therefore pick will try */
596 : /* not to return it */
597 0 : req->ns = nameserver_pick();
598 0 : if (req->ns == last_ns) {
599 : /* ... but pick did return it */
600 : /* not a lot of point in trying again with the */
601 : /* same server */
602 0 : return 1;
603 : }
604 :
605 0 : req->reissue_count++;
606 0 : req->tx_count = 0;
607 0 : req->transmit_me = 1;
608 :
609 0 : return 0;
610 : }
611 :
612 : /* this function looks for space on the inflight queue and promotes */
613 : /* requests from the waiting queue if it can. */
614 : static void
615 0 : evdns_requests_pump_waiting_queue(void) {
616 0 : while (global_requests_inflight < global_max_requests_inflight &&
617 : global_requests_waiting) {
618 : struct request *req;
619 : /* move a request from the waiting queue to the inflight queue */
620 0 : assert(req_waiting_head);
621 0 : if (req_waiting_head->next == req_waiting_head) {
622 : /* only one item in the queue */
623 0 : req = req_waiting_head;
624 0 : req_waiting_head = NULL;
625 : } else {
626 0 : req = req_waiting_head;
627 0 : req->next->prev = req->prev;
628 0 : req->prev->next = req->next;
629 0 : req_waiting_head = req->next;
630 : }
631 :
632 0 : global_requests_waiting--;
633 0 : global_requests_inflight++;
634 :
635 0 : req->ns = nameserver_pick();
636 0 : request_trans_id_set(req, transaction_id_pick());
637 :
638 0 : evdns_request_insert(req, &req_head);
639 0 : evdns_request_transmit(req);
640 0 : evdns_transmit();
641 : }
642 0 : }
643 :
644 : static void
645 0 : reply_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply) {
646 0 : switch (req->request_type) {
647 : case TYPE_A:
648 0 : if (reply)
649 0 : req->user_callback(DNS_ERR_NONE, DNS_IPv4_A,
650 0 : reply->data.a.addrcount, ttl,
651 0 : reply->data.a.addresses,
652 : req->user_pointer);
653 : else
654 0 : req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
655 0 : return;
656 : case TYPE_PTR:
657 0 : if (reply) {
658 0 : char *name = reply->data.ptr.name;
659 0 : req->user_callback(DNS_ERR_NONE, DNS_PTR, 1, ttl,
660 : &name, req->user_pointer);
661 : } else {
662 0 : req->user_callback(err, 0, 0, 0, NULL,
663 : req->user_pointer);
664 : }
665 0 : return;
666 : case TYPE_AAAA:
667 0 : if (reply)
668 0 : req->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA,
669 0 : reply->data.aaaa.addrcount, ttl,
670 0 : reply->data.aaaa.addresses,
671 : req->user_pointer);
672 : else
673 0 : req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
674 0 : return;
675 : }
676 0 : assert(0);
677 : }
678 :
679 : /* this processes a parsed reply packet */
680 : static void
681 0 : reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply) {
682 : int error;
683 : static const int error_codes[] = {DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST, DNS_ERR_NOTIMPL, DNS_ERR_REFUSED};
684 :
685 0 : if (flags & 0x020f || !reply || !reply->have_answer) {
686 : /* there was an error */
687 0 : if (flags & 0x0200) {
688 0 : error = DNS_ERR_TRUNCATED;
689 : } else {
690 0 : u16 error_code = (flags & 0x000f) - 1;
691 0 : if (error_code > 4) {
692 0 : error = DNS_ERR_UNKNOWN;
693 : } else {
694 0 : error = error_codes[error_code];
695 : }
696 : }
697 :
698 0 : switch(error) {
699 : case DNS_ERR_NOTIMPL:
700 : case DNS_ERR_REFUSED:
701 : /* we regard these errors as marking a bad nameserver */
702 0 : if (req->reissue_count < global_max_reissues) {
703 : char msg[64];
704 0 : evutil_snprintf(msg, sizeof(msg),
705 : "Bad response %d (%s)",
706 : error, evdns_err_to_string(error));
707 0 : nameserver_failed(req->ns, msg);
708 0 : if (!request_reissue(req)) return;
709 : }
710 0 : break;
711 : case DNS_ERR_SERVERFAILED:
712 : /* rcode 2 (servfailed) sometimes means "we are broken" and
713 : * sometimes (with some binds) means "that request was very
714 : * confusing." Treat this as a timeout, not a failure.
715 : */
716 0 : log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver %s; "
717 : "will allow the request to time out.",
718 0 : debug_ntoa(req->ns->address));
719 0 : break;
720 : default:
721 : /* we got a good reply from the nameserver */
722 0 : nameserver_up(req->ns);
723 : }
724 :
725 0 : if (req->search_state && req->request_type != TYPE_PTR) {
726 : /* if we have a list of domains to search in, try the next one */
727 0 : if (!search_try_next(req)) {
728 : /* a new request was issued so this request is finished and */
729 : /* the user callback will be made when that request (or a */
730 : /* child of it) finishes. */
731 0 : request_finished(req, &req_head);
732 0 : return;
733 : }
734 : }
735 :
736 : /* all else failed. Pass the failure up */
737 0 : reply_callback(req, 0, error, NULL);
738 0 : request_finished(req, &req_head);
739 : } else {
740 : /* all ok, tell the user */
741 0 : reply_callback(req, ttl, 0, reply);
742 0 : nameserver_up(req->ns);
743 0 : request_finished(req, &req_head);
744 : }
745 : }
746 :
747 : static int
748 0 : name_parse(u8 *packet, int length, int *idx, char *name_out, int name_out_len) {
749 0 : int name_end = -1;
750 0 : int j = *idx;
751 0 : int ptr_count = 0;
752 : #define GET32(x) do { if (j + 4 > length) goto err; memcpy(&_t32, packet + j, 4); j += 4; x = ntohl(_t32); } while(0)
753 : #define GET16(x) do { if (j + 2 > length) goto err; memcpy(&_t, packet + j, 2); j += 2; x = ntohs(_t); } while(0)
754 : #define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while(0)
755 :
756 0 : char *cp = name_out;
757 0 : const char *const end = name_out + name_out_len;
758 :
759 : /* Normally, names are a series of length prefixed strings terminated */
760 : /* with a length of 0 (the lengths are u8's < 63). */
761 : /* However, the length can start with a pair of 1 bits and that */
762 : /* means that the next 14 bits are a pointer within the current */
763 : /* packet. */
764 :
765 : for(;;) {
766 : u8 label_len;
767 0 : if (j >= length) return -1;
768 0 : GET8(label_len);
769 0 : if (!label_len) break;
770 0 : if (label_len & 0xc0) {
771 : u8 ptr_low;
772 0 : GET8(ptr_low);
773 0 : if (name_end < 0) name_end = j;
774 0 : j = (((int)label_len & 0x3f) << 8) + ptr_low;
775 : /* Make sure that the target offset is in-bounds. */
776 0 : if (j < 0 || j >= length) return -1;
777 : /* If we've jumped more times than there are characters in the
778 : * message, we must have a loop. */
779 0 : if (++ptr_count > length) return -1;
780 0 : continue;
781 : }
782 0 : if (label_len > 63) return -1;
783 0 : if (cp != name_out) {
784 0 : if (cp + 1 >= end) return -1;
785 0 : *cp++ = '.';
786 : }
787 0 : if (cp + label_len >= end) return -1;
788 0 : memcpy(cp, packet + j, label_len);
789 0 : cp += label_len;
790 0 : j += label_len;
791 0 : }
792 0 : if (cp >= end) return -1;
793 0 : *cp = '\0';
794 0 : if (name_end < 0)
795 0 : *idx = j;
796 : else
797 0 : *idx = name_end;
798 0 : return 0;
799 : err:
800 0 : return -1;
801 : }
802 :
803 : /* parses a raw request from a nameserver */
804 : static int
805 0 : reply_parse(u8 *packet, int length) {
806 0 : int j = 0; /* index into packet */
807 : u16 _t; /* used by the macros */
808 : u32 _t32; /* used by the macros */
809 : char tmp_name[256]; /* used by the macros */
810 :
811 : u16 trans_id, questions, answers, authority, additional, datalength;
812 0 : u16 flags = 0;
813 0 : u32 ttl, ttl_r = 0xffffffff;
814 : struct reply reply;
815 0 : struct request *req = NULL;
816 : unsigned int i;
817 :
818 0 : GET16(trans_id);
819 0 : GET16(flags);
820 0 : GET16(questions);
821 0 : GET16(answers);
822 0 : GET16(authority);
823 0 : GET16(additional);
824 : (void) authority; /* suppress "unused variable" warnings. */
825 : (void) additional; /* suppress "unused variable" warnings. */
826 :
827 0 : req = request_find_from_trans_id(trans_id);
828 0 : if (!req) return -1;
829 :
830 0 : memset(&reply, 0, sizeof(reply));
831 :
832 : /* If it's not an answer, it doesn't correspond to any request. */
833 0 : if (!(flags & 0x8000)) return -1; /* must be an answer */
834 0 : if (flags & 0x020f) {
835 : /* there was an error */
836 0 : goto err;
837 : }
838 : /* if (!answers) return; */ /* must have an answer of some form */
839 :
840 : /* This macro skips a name in the DNS reply. */
841 : #define SKIP_NAME \
842 : do { tmp_name[0] = '\0'; \
843 : if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0) \
844 : goto err; \
845 : } while(0);
846 :
847 0 : reply.type = req->request_type;
848 :
849 : /* skip over each question in the reply */
850 0 : for (i = 0; i < questions; ++i) {
851 : /* the question looks like
852 : * <label:name><u16:type><u16:class>
853 : */
854 0 : SKIP_NAME;
855 0 : j += 4;
856 0 : if (j > length) goto err;
857 : }
858 :
859 : /* now we have the answer section which looks like
860 : * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
861 : */
862 :
863 0 : for (i = 0; i < answers; ++i) {
864 : u16 type, class;
865 :
866 0 : SKIP_NAME;
867 0 : GET16(type);
868 0 : GET16(class);
869 0 : GET32(ttl);
870 0 : GET16(datalength);
871 :
872 0 : if (type == TYPE_A && class == CLASS_INET) {
873 : int addrcount, addrtocopy;
874 0 : if (req->request_type != TYPE_A) {
875 0 : j += datalength; continue;
876 : }
877 0 : if ((datalength & 3) != 0) /* not an even number of As. */
878 0 : goto err;
879 0 : addrcount = datalength >> 2;
880 0 : addrtocopy = MIN(MAX_ADDRS - reply.data.a.addrcount, (unsigned)addrcount);
881 :
882 0 : ttl_r = MIN(ttl_r, ttl);
883 : /* we only bother with the first four addresses. */
884 0 : if (j + 4*addrtocopy > length) goto err;
885 0 : memcpy(&reply.data.a.addresses[reply.data.a.addrcount],
886 0 : packet + j, 4*addrtocopy);
887 0 : j += 4*addrtocopy;
888 0 : reply.data.a.addrcount += addrtocopy;
889 0 : reply.have_answer = 1;
890 0 : if (reply.data.a.addrcount == MAX_ADDRS) break;
891 0 : } else if (type == TYPE_PTR && class == CLASS_INET) {
892 0 : if (req->request_type != TYPE_PTR) {
893 0 : j += datalength; continue;
894 : }
895 0 : if (name_parse(packet, length, &j, reply.data.ptr.name,
896 : sizeof(reply.data.ptr.name))<0)
897 0 : goto err;
898 0 : ttl_r = MIN(ttl_r, ttl);
899 0 : reply.have_answer = 1;
900 0 : break;
901 0 : } else if (type == TYPE_AAAA && class == CLASS_INET) {
902 : int addrcount, addrtocopy;
903 0 : if (req->request_type != TYPE_AAAA) {
904 0 : j += datalength; continue;
905 : }
906 0 : if ((datalength & 15) != 0) /* not an even number of AAAAs. */
907 0 : goto err;
908 0 : addrcount = datalength >> 4; /* each address is 16 bytes long */
909 0 : addrtocopy = MIN(MAX_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount);
910 0 : ttl_r = MIN(ttl_r, ttl);
911 :
912 : /* we only bother with the first four addresses. */
913 0 : if (j + 16*addrtocopy > length) goto err;
914 0 : memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount],
915 0 : packet + j, 16*addrtocopy);
916 0 : reply.data.aaaa.addrcount += addrtocopy;
917 0 : j += 16*addrtocopy;
918 0 : reply.have_answer = 1;
919 0 : if (reply.data.aaaa.addrcount == MAX_ADDRS) break;
920 : } else {
921 : /* skip over any other type of resource */
922 0 : j += datalength;
923 : }
924 : }
925 :
926 0 : reply_handle(req, flags, ttl_r, &reply);
927 0 : return 0;
928 : err:
929 0 : if (req)
930 0 : reply_handle(req, flags, 0, NULL);
931 0 : return -1;
932 : }
933 :
934 : /* Parse a raw request (packet,length) sent to a nameserver port (port) from */
935 : /* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
936 : /* callback. */
937 : static int
938 0 : request_parse(u8 *packet, int length, struct evdns_server_port *port, struct sockaddr *addr, socklen_t addrlen)
939 : {
940 0 : int j = 0; /* index into packet */
941 : u16 _t; /* used by the macros */
942 : char tmp_name[256]; /* used by the macros */
943 :
944 : int i;
945 : u16 trans_id, flags, questions, answers, authority, additional;
946 0 : struct server_request *server_req = NULL;
947 :
948 : /* Get the header fields */
949 0 : GET16(trans_id);
950 0 : GET16(flags);
951 0 : GET16(questions);
952 0 : GET16(answers);
953 0 : GET16(authority);
954 0 : GET16(additional);
955 :
956 0 : if (flags & 0x8000) return -1; /* Must not be an answer. */
957 0 : flags &= 0x0110; /* Only RD and CD get preserved. */
958 :
959 0 : server_req = malloc(sizeof(struct server_request));
960 0 : if (server_req == NULL) return -1;
961 0 : memset(server_req, 0, sizeof(struct server_request));
962 :
963 0 : server_req->trans_id = trans_id;
964 0 : memcpy(&server_req->addr, addr, addrlen);
965 0 : server_req->addrlen = addrlen;
966 :
967 0 : server_req->base.flags = flags;
968 0 : server_req->base.nquestions = 0;
969 0 : server_req->base.questions = malloc(sizeof(struct evdns_server_question *) * questions);
970 0 : if (server_req->base.questions == NULL)
971 0 : goto err;
972 :
973 0 : for (i = 0; i < questions; ++i) {
974 : u16 type, class;
975 : struct evdns_server_question *q;
976 : int namelen;
977 0 : if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)
978 0 : goto err;
979 0 : GET16(type);
980 0 : GET16(class);
981 0 : namelen = strlen(tmp_name);
982 0 : q = malloc(sizeof(struct evdns_server_question) + namelen);
983 0 : if (!q)
984 0 : goto err;
985 0 : q->type = type;
986 0 : q->dns_question_class = class;
987 0 : memcpy(q->name, tmp_name, namelen+1);
988 0 : server_req->base.questions[server_req->base.nquestions++] = q;
989 : }
990 :
991 : /* Ignore answers, authority, and additional. */
992 :
993 0 : server_req->port = port;
994 0 : port->refcnt++;
995 :
996 : /* Only standard queries are supported. */
997 0 : if (flags & 0x7800) {
998 0 : evdns_server_request_respond(&(server_req->base), DNS_ERR_NOTIMPL);
999 0 : return -1;
1000 : }
1001 :
1002 0 : port->user_callback(&(server_req->base), port->user_data);
1003 :
1004 0 : return 0;
1005 : err:
1006 0 : if (server_req) {
1007 0 : if (server_req->base.questions) {
1008 0 : for (i = 0; i < server_req->base.nquestions; ++i)
1009 0 : free(server_req->base.questions[i]);
1010 0 : free(server_req->base.questions);
1011 : }
1012 0 : free(server_req);
1013 : }
1014 0 : return -1;
1015 :
1016 : #undef SKIP_NAME
1017 : #undef GET32
1018 : #undef GET16
1019 : #undef GET8
1020 : }
1021 :
1022 : static u16
1023 0 : default_transaction_id_fn(void)
1024 : {
1025 : u16 trans_id;
1026 : #ifdef DNS_USE_CPU_CLOCK_FOR_ID
1027 : struct timespec ts;
1028 : static int clkid = -1;
1029 0 : if (clkid == -1) {
1030 0 : clkid = CLOCK_REALTIME;
1031 : #ifdef CLOCK_MONOTONIC
1032 0 : if (clock_gettime(CLOCK_MONOTONIC, &ts) != -1)
1033 0 : clkid = CLOCK_MONOTONIC;
1034 : #endif
1035 : }
1036 0 : if (clock_gettime(clkid, &ts) == -1)
1037 0 : event_err(1, "clock_gettime");
1038 0 : trans_id = ts.tv_nsec & 0xffff;
1039 : #endif
1040 :
1041 : #ifdef DNS_USE_FTIME_FOR_ID
1042 : struct _timeb tb;
1043 : _ftime(&tb);
1044 : trans_id = tb.millitm & 0xffff;
1045 : #endif
1046 :
1047 : #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
1048 : struct timeval tv;
1049 : evutil_gettimeofday(&tv, NULL);
1050 : trans_id = tv.tv_usec & 0xffff;
1051 : #endif
1052 :
1053 : #ifdef DNS_USE_OPENSSL_FOR_ID
1054 : if (RAND_pseudo_bytes((u8 *) &trans_id, 2) == -1) {
1055 : /* in the case that the RAND call fails we back */
1056 : /* down to using gettimeofday. */
1057 : /*
1058 : struct timeval tv;
1059 : evutil_gettimeofday(&tv, NULL);
1060 : trans_id = tv.tv_usec & 0xffff;
1061 : */
1062 : abort();
1063 : }
1064 : #endif
1065 0 : return trans_id;
1066 : }
1067 :
1068 : static ev_uint16_t (*trans_id_function)(void) = default_transaction_id_fn;
1069 :
1070 : void
1071 0 : evdns_set_transaction_id_fn(ev_uint16_t (*fn)(void))
1072 : {
1073 0 : if (fn)
1074 0 : trans_id_function = fn;
1075 : else
1076 0 : trans_id_function = default_transaction_id_fn;
1077 0 : }
1078 :
1079 : /* Try to choose a strong transaction id which isn't already in flight */
1080 : static u16
1081 0 : transaction_id_pick(void) {
1082 : for (;;) {
1083 0 : const struct request *req = req_head, *started_at;
1084 0 : u16 trans_id = trans_id_function();
1085 :
1086 0 : if (trans_id == 0xffff) continue;
1087 : /* now check to see if that id is already inflight */
1088 0 : req = started_at = req_head;
1089 0 : if (req) {
1090 : do {
1091 0 : if (req->trans_id == trans_id) break;
1092 0 : req = req->next;
1093 0 : } while (req != started_at);
1094 : }
1095 : /* we didn't find it, so this is a good id */
1096 0 : if (req == started_at) return trans_id;
1097 0 : }
1098 : }
1099 :
1100 : /* choose a namesever to use. This function will try to ignore */
1101 : /* nameservers which we think are down and load balance across the rest */
1102 : /* by updating the server_head global each time. */
1103 : static struct nameserver *
1104 0 : nameserver_pick(void) {
1105 0 : struct nameserver *started_at = server_head, *picked;
1106 0 : if (!server_head) return NULL;
1107 :
1108 : /* if we don't have any good nameservers then there's no */
1109 : /* point in trying to find one. */
1110 0 : if (!global_good_nameservers) {
1111 0 : server_head = server_head->next;
1112 0 : return server_head;
1113 : }
1114 :
1115 : /* remember that nameservers are in a circular list */
1116 : for (;;) {
1117 0 : if (server_head->state) {
1118 : /* we think this server is currently good */
1119 0 : picked = server_head;
1120 0 : server_head = server_head->next;
1121 0 : return picked;
1122 : }
1123 :
1124 0 : server_head = server_head->next;
1125 0 : if (server_head == started_at) {
1126 : /* all the nameservers seem to be down */
1127 : /* so we just return this one and hope for the */
1128 : /* best */
1129 0 : assert(global_good_nameservers == 0);
1130 0 : picked = server_head;
1131 0 : server_head = server_head->next;
1132 0 : return picked;
1133 : }
1134 0 : }
1135 : }
1136 :
1137 : /* this is called when a namesever socket is ready for reading */
1138 : static void
1139 0 : nameserver_read(struct nameserver *ns) {
1140 : u8 packet[1500];
1141 :
1142 : for (;;) {
1143 0 : const int r = recv(ns->socket, packet, sizeof(packet), 0);
1144 0 : if (r < 0) {
1145 0 : int err = last_error(ns->socket);
1146 0 : if (error_is_eagain(err)) return;
1147 0 : nameserver_failed(ns, strerror(err));
1148 0 : return;
1149 : }
1150 0 : ns->timedout = 0;
1151 0 : reply_parse(packet, r);
1152 0 : }
1153 : }
1154 :
1155 : /* Read a packet from a DNS client on a server port s, parse it, and */
1156 : /* act accordingly. */
1157 : static void
1158 0 : server_port_read(struct evdns_server_port *s) {
1159 : u8 packet[1500];
1160 : struct sockaddr_storage addr;
1161 : socklen_t addrlen;
1162 : int r;
1163 :
1164 : for (;;) {
1165 0 : addrlen = sizeof(struct sockaddr_storage);
1166 0 : r = recvfrom(s->socket, packet, sizeof(packet), 0,
1167 : (struct sockaddr*) &addr, &addrlen);
1168 0 : if (r < 0) {
1169 0 : int err = last_error(s->socket);
1170 0 : if (error_is_eagain(err)) return;
1171 0 : log(EVDNS_LOG_WARN, "Error %s (%d) while reading request.",
1172 : strerror(err), err);
1173 0 : return;
1174 : }
1175 0 : request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen);
1176 0 : }
1177 : }
1178 :
1179 : /* Try to write all pending replies on a given DNS server port. */
1180 : static void
1181 0 : server_port_flush(struct evdns_server_port *port)
1182 : {
1183 0 : while (port->pending_replies) {
1184 0 : struct server_request *req = port->pending_replies;
1185 0 : int r = sendto(port->socket, req->response, req->response_len, 0,
1186 0 : (struct sockaddr*) &req->addr, req->addrlen);
1187 0 : if (r < 0) {
1188 0 : int err = last_error(port->socket);
1189 0 : if (error_is_eagain(err))
1190 0 : return;
1191 0 : log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", strerror(err), err);
1192 : }
1193 0 : if (server_request_free(req)) {
1194 : /* we released the last reference to req->port. */
1195 0 : return;
1196 : }
1197 : }
1198 :
1199 : /* We have no more pending requests; stop listening for 'writeable' events. */
1200 0 : (void) event_del(&port->event);
1201 0 : event_set(&port->event, port->socket, EV_READ | EV_PERSIST,
1202 : server_port_ready_callback, port);
1203 0 : if (event_add(&port->event, NULL) < 0) {
1204 0 : log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server.");
1205 : /* ???? Do more? */
1206 : }
1207 : }
1208 :
1209 : /* set if we are waiting for the ability to write to this server. */
1210 : /* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
1211 : /* we stop these events. */
1212 : static void
1213 0 : nameserver_write_waiting(struct nameserver *ns, char waiting) {
1214 0 : if (ns->write_waiting == waiting) return;
1215 :
1216 0 : ns->write_waiting = waiting;
1217 0 : (void) event_del(&ns->event);
1218 0 : event_set(&ns->event, ns->socket, EV_READ | (waiting ? EV_WRITE : 0) | EV_PERSIST,
1219 : nameserver_ready_callback, ns);
1220 0 : if (event_add(&ns->event, NULL) < 0) {
1221 0 : log(EVDNS_LOG_WARN, "Error from libevent when adding event for %s",
1222 : debug_ntoa(ns->address));
1223 : /* ???? Do more? */
1224 : }
1225 : }
1226 :
1227 : /* a callback function. Called by libevent when the kernel says that */
1228 : /* a nameserver socket is ready for writing or reading */
1229 : static void
1230 0 : nameserver_ready_callback(int fd, short events, void *arg) {
1231 0 : struct nameserver *ns = (struct nameserver *) arg;
1232 : (void)fd;
1233 :
1234 0 : if (events & EV_WRITE) {
1235 0 : ns->choked = 0;
1236 0 : if (!evdns_transmit()) {
1237 0 : nameserver_write_waiting(ns, 0);
1238 : }
1239 : }
1240 0 : if (events & EV_READ) {
1241 0 : nameserver_read(ns);
1242 : }
1243 0 : }
1244 :
1245 : /* a callback function. Called by libevent when the kernel says that */
1246 : /* a server socket is ready for writing or reading. */
1247 : static void
1248 0 : server_port_ready_callback(int fd, short events, void *arg) {
1249 0 : struct evdns_server_port *port = (struct evdns_server_port *) arg;
1250 : (void) fd;
1251 :
1252 0 : if (events & EV_WRITE) {
1253 0 : port->choked = 0;
1254 0 : server_port_flush(port);
1255 : }
1256 0 : if (events & EV_READ) {
1257 0 : server_port_read(port);
1258 : }
1259 0 : }
1260 :
1261 : /* This is an inefficient representation; only use it via the dnslabel_table_*
1262 : * functions, so that is can be safely replaced with something smarter later. */
1263 : #define MAX_LABELS 128
1264 : /* Structures used to implement name compression */
1265 : struct dnslabel_entry { char *v; off_t pos; };
1266 : struct dnslabel_table {
1267 : int n_labels; /* number of current entries */
1268 : /* map from name to position in message */
1269 : struct dnslabel_entry labels[MAX_LABELS];
1270 : };
1271 :
1272 : /* Initialize dnslabel_table. */
1273 : static void
1274 0 : dnslabel_table_init(struct dnslabel_table *table)
1275 : {
1276 0 : table->n_labels = 0;
1277 0 : }
1278 :
1279 : /* Free all storage held by table, but not the table itself. */
1280 : static void
1281 0 : dnslabel_clear(struct dnslabel_table *table)
1282 : {
1283 : int i;
1284 0 : for (i = 0; i < table->n_labels; ++i)
1285 0 : free(table->labels[i].v);
1286 0 : table->n_labels = 0;
1287 0 : }
1288 :
1289 : /* return the position of the label in the current message, or -1 if the label */
1290 : /* hasn't been used yet. */
1291 : static int
1292 0 : dnslabel_table_get_pos(const struct dnslabel_table *table, const char *label)
1293 : {
1294 : int i;
1295 0 : for (i = 0; i < table->n_labels; ++i) {
1296 0 : if (!strcmp(label, table->labels[i].v))
1297 0 : return table->labels[i].pos;
1298 : }
1299 0 : return -1;
1300 : }
1301 :
1302 : /* remember that we've used the label at position pos */
1303 : static int
1304 0 : dnslabel_table_add(struct dnslabel_table *table, const char *label, off_t pos)
1305 : {
1306 : char *v;
1307 : int p;
1308 0 : if (table->n_labels == MAX_LABELS)
1309 0 : return (-1);
1310 0 : v = strdup(label);
1311 0 : if (v == NULL)
1312 0 : return (-1);
1313 0 : p = table->n_labels++;
1314 0 : table->labels[p].v = v;
1315 0 : table->labels[p].pos = pos;
1316 :
1317 0 : return (0);
1318 : }
1319 :
1320 : /* Converts a string to a length-prefixed set of DNS labels, starting */
1321 : /* at buf[j]. name and buf must not overlap. name_len should be the length */
1322 : /* of name. table is optional, and is used for compression. */
1323 : /* */
1324 : /* Input: abc.def */
1325 : /* Output: <3>abc<3>def<0> */
1326 : /* */
1327 : /* Returns the first index after the encoded name, or negative on error. */
1328 : /* -1 label was > 63 bytes */
1329 : /* -2 name too long to fit in buffer. */
1330 : /* */
1331 : static off_t
1332 0 : dnsname_to_labels(u8 *const buf, size_t buf_len, off_t j,
1333 : const char *name, const int name_len,
1334 : struct dnslabel_table *table) {
1335 0 : const char *end = name + name_len;
1336 0 : int ref = 0;
1337 : u16 _t;
1338 :
1339 : #define APPEND16(x) do { \
1340 : if (j + 2 > (off_t)buf_len) \
1341 : goto overflow; \
1342 : _t = htons(x); \
1343 : memcpy(buf + j, &_t, 2); \
1344 : j += 2; \
1345 : } while (0)
1346 : #define APPEND32(x) do { \
1347 : if (j + 4 > (off_t)buf_len) \
1348 : goto overflow; \
1349 : _t32 = htonl(x); \
1350 : memcpy(buf + j, &_t32, 4); \
1351 : j += 4; \
1352 : } while (0)
1353 :
1354 0 : if (name_len > 255) return -2;
1355 :
1356 : for (;;) {
1357 0 : const char *const start = name;
1358 0 : if (table && (ref = dnslabel_table_get_pos(table, name)) >= 0) {
1359 0 : APPEND16(ref | 0xc000);
1360 0 : return j;
1361 : }
1362 0 : name = strchr(name, '.');
1363 0 : if (!name) {
1364 0 : const unsigned int label_len = end - start;
1365 0 : if (label_len > 63) return -1;
1366 0 : if ((size_t)(j+label_len+1) > buf_len) return -2;
1367 0 : if (table) dnslabel_table_add(table, start, j);
1368 0 : buf[j++] = label_len;
1369 :
1370 0 : memcpy(buf + j, start, end - start);
1371 0 : j += end - start;
1372 : break;
1373 : } else {
1374 : /* append length of the label. */
1375 0 : const unsigned int label_len = name - start;
1376 0 : if (label_len > 63) return -1;
1377 0 : if ((size_t)(j+label_len+1) > buf_len) return -2;
1378 0 : if (table) dnslabel_table_add(table, start, j);
1379 0 : buf[j++] = label_len;
1380 :
1381 0 : memcpy(buf + j, start, name - start);
1382 0 : j += name - start;
1383 : /* hop over the '.' */
1384 0 : name++;
1385 : }
1386 0 : }
1387 :
1388 : /* the labels must be terminated by a 0. */
1389 : /* It's possible that the name ended in a . */
1390 : /* in which case the zero is already there */
1391 0 : if (!j || buf[j-1]) buf[j++] = 0;
1392 0 : return j;
1393 : overflow:
1394 0 : return (-2);
1395 : }
1396 :
1397 : /* Finds the length of a dns request for a DNS name of the given */
1398 : /* length. The actual request may be smaller than the value returned */
1399 : /* here */
1400 : static int
1401 0 : evdns_request_len(const int name_len) {
1402 0 : return 96 + /* length of the DNS standard header */
1403 : name_len + 2 +
1404 : 4; /* space for the resource type */
1405 : }
1406 :
1407 : /* build a dns request packet into buf. buf should be at least as long */
1408 : /* as evdns_request_len told you it should be. */
1409 : /* */
1410 : /* Returns the amount of space used. Negative on error. */
1411 : static int
1412 0 : evdns_request_data_build(const char *const name, const int name_len,
1413 : const u16 trans_id, const u16 type, const u16 class,
1414 : u8 *const buf, size_t buf_len) {
1415 0 : off_t j = 0; /* current offset into buf */
1416 : u16 _t; /* used by the macros */
1417 :
1418 0 : APPEND16(trans_id);
1419 0 : APPEND16(0x0100); /* standard query, recusion needed */
1420 0 : APPEND16(1); /* one question */
1421 0 : APPEND16(0); /* no answers */
1422 0 : APPEND16(0); /* no authority */
1423 0 : APPEND16(0); /* no additional */
1424 :
1425 0 : j = dnsname_to_labels(buf, buf_len, j, name, name_len, NULL);
1426 0 : if (j < 0) {
1427 0 : return (int)j;
1428 : }
1429 :
1430 0 : APPEND16(type);
1431 0 : APPEND16(class);
1432 :
1433 0 : return (int)j;
1434 : overflow:
1435 0 : return (-1);
1436 : }
1437 :
1438 : /* exported function */
1439 : struct evdns_server_port *
1440 0 : evdns_add_server_port(int socket, int is_tcp, evdns_request_callback_fn_type cb, void *user_data)
1441 : {
1442 : struct evdns_server_port *port;
1443 0 : if (!(port = malloc(sizeof(struct evdns_server_port))))
1444 0 : return NULL;
1445 0 : memset(port, 0, sizeof(struct evdns_server_port));
1446 :
1447 0 : assert(!is_tcp); /* TCP sockets not yet implemented */
1448 0 : port->socket = socket;
1449 0 : port->refcnt = 1;
1450 0 : port->choked = 0;
1451 0 : port->closing = 0;
1452 0 : port->user_callback = cb;
1453 0 : port->user_data = user_data;
1454 0 : port->pending_replies = NULL;
1455 :
1456 0 : event_set(&port->event, port->socket, EV_READ | EV_PERSIST,
1457 : server_port_ready_callback, port);
1458 0 : event_add(&port->event, NULL); /* check return. */
1459 0 : return port;
1460 : }
1461 :
1462 : /* exported function */
1463 : void
1464 0 : evdns_close_server_port(struct evdns_server_port *port)
1465 : {
1466 0 : if (--port->refcnt == 0)
1467 0 : server_port_free(port);
1468 0 : port->closing = 1;
1469 0 : }
1470 :
1471 : /* exported function */
1472 : int
1473 0 : evdns_server_request_add_reply(struct evdns_server_request *_req, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data)
1474 : {
1475 0 : struct server_request *req = TO_SERVER_REQUEST(_req);
1476 : struct server_reply_item **itemp, *item;
1477 : int *countp;
1478 :
1479 0 : if (req->response) /* have we already answered? */
1480 0 : return (-1);
1481 :
1482 0 : switch (section) {
1483 : case EVDNS_ANSWER_SECTION:
1484 0 : itemp = &req->answer;
1485 0 : countp = &req->n_answer;
1486 0 : break;
1487 : case EVDNS_AUTHORITY_SECTION:
1488 0 : itemp = &req->authority;
1489 0 : countp = &req->n_authority;
1490 0 : break;
1491 : case EVDNS_ADDITIONAL_SECTION:
1492 0 : itemp = &req->additional;
1493 0 : countp = &req->n_additional;
1494 0 : break;
1495 : default:
1496 0 : return (-1);
1497 : }
1498 0 : while (*itemp) {
1499 0 : itemp = &((*itemp)->next);
1500 : }
1501 0 : item = malloc(sizeof(struct server_reply_item));
1502 0 : if (!item)
1503 0 : return -1;
1504 0 : item->next = NULL;
1505 0 : if (!(item->name = strdup(name))) {
1506 0 : free(item);
1507 0 : return -1;
1508 : }
1509 0 : item->type = type;
1510 0 : item->dns_question_class = class;
1511 0 : item->ttl = ttl;
1512 0 : item->is_name = is_name != 0;
1513 0 : item->datalen = 0;
1514 0 : item->data = NULL;
1515 0 : if (data) {
1516 0 : if (item->is_name) {
1517 0 : if (!(item->data = strdup(data))) {
1518 0 : free(item->name);
1519 0 : free(item);
1520 0 : return -1;
1521 : }
1522 0 : item->datalen = (u16)-1;
1523 : } else {
1524 0 : if (!(item->data = malloc(datalen))) {
1525 0 : free(item->name);
1526 0 : free(item);
1527 0 : return -1;
1528 : }
1529 0 : item->datalen = datalen;
1530 0 : memcpy(item->data, data, datalen);
1531 : }
1532 : }
1533 :
1534 0 : *itemp = item;
1535 0 : ++(*countp);
1536 0 : return 0;
1537 : }
1538 :
1539 : /* exported function */
1540 : int
1541 0 : evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl)
1542 : {
1543 0 : return evdns_server_request_add_reply(
1544 : req, EVDNS_ANSWER_SECTION, name, TYPE_A, CLASS_INET,
1545 : ttl, n*4, 0, addrs);
1546 : }
1547 :
1548 : /* exported function */
1549 : int
1550 0 : evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl)
1551 : {
1552 0 : return evdns_server_request_add_reply(
1553 : req, EVDNS_ANSWER_SECTION, name, TYPE_AAAA, CLASS_INET,
1554 : ttl, n*16, 0, addrs);
1555 : }
1556 :
1557 : /* exported function */
1558 : int
1559 0 : evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl)
1560 : {
1561 : u32 a;
1562 : char buf[32];
1563 0 : assert(in || inaddr_name);
1564 0 : assert(!(in && inaddr_name));
1565 0 : if (in) {
1566 0 : a = ntohl(in->s_addr);
1567 0 : evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
1568 0 : (int)(u8)((a )&0xff),
1569 0 : (int)(u8)((a>>8 )&0xff),
1570 0 : (int)(u8)((a>>16)&0xff),
1571 0 : (int)(u8)((a>>24)&0xff));
1572 0 : inaddr_name = buf;
1573 : }
1574 0 : return evdns_server_request_add_reply(
1575 : req, EVDNS_ANSWER_SECTION, inaddr_name, TYPE_PTR, CLASS_INET,
1576 : ttl, -1, 1, hostname);
1577 : }
1578 :
1579 : /* exported function */
1580 : int
1581 0 : evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl)
1582 : {
1583 0 : return evdns_server_request_add_reply(
1584 : req, EVDNS_ANSWER_SECTION, name, TYPE_CNAME, CLASS_INET,
1585 : ttl, -1, 1, cname);
1586 : }
1587 :
1588 :
1589 : static int
1590 0 : evdns_server_request_format_response(struct server_request *req, int err)
1591 : {
1592 : unsigned char buf[1500];
1593 0 : size_t buf_len = sizeof(buf);
1594 0 : off_t j = 0, r;
1595 : u16 _t;
1596 : u32 _t32;
1597 : int i;
1598 : u16 flags;
1599 : struct dnslabel_table table;
1600 :
1601 0 : if (err < 0 || err > 15) return -1;
1602 :
1603 : /* Set response bit and error code; copy OPCODE and RD fields from
1604 : * question; copy RA and AA if set by caller. */
1605 0 : flags = req->base.flags;
1606 0 : flags |= (0x8000 | err);
1607 :
1608 0 : dnslabel_table_init(&table);
1609 0 : APPEND16(req->trans_id);
1610 0 : APPEND16(flags);
1611 0 : APPEND16(req->base.nquestions);
1612 0 : APPEND16(req->n_answer);
1613 0 : APPEND16(req->n_authority);
1614 0 : APPEND16(req->n_additional);
1615 :
1616 : /* Add questions. */
1617 0 : for (i=0; i < req->base.nquestions; ++i) {
1618 0 : const char *s = req->base.questions[i]->name;
1619 0 : j = dnsname_to_labels(buf, buf_len, j, s, strlen(s), &table);
1620 0 : if (j < 0) {
1621 0 : dnslabel_clear(&table);
1622 0 : return (int) j;
1623 : }
1624 0 : APPEND16(req->base.questions[i]->type);
1625 0 : APPEND16(req->base.questions[i]->dns_question_class);
1626 : }
1627 :
1628 : /* Add answer, authority, and additional sections. */
1629 0 : for (i=0; i<3; ++i) {
1630 : struct server_reply_item *item;
1631 0 : if (i==0)
1632 0 : item = req->answer;
1633 0 : else if (i==1)
1634 0 : item = req->authority;
1635 : else
1636 0 : item = req->additional;
1637 0 : while (item) {
1638 0 : r = dnsname_to_labels(buf, buf_len, j, item->name, strlen(item->name), &table);
1639 0 : if (r < 0)
1640 0 : goto overflow;
1641 0 : j = r;
1642 :
1643 0 : APPEND16(item->type);
1644 0 : APPEND16(item->dns_question_class);
1645 0 : APPEND32(item->ttl);
1646 0 : if (item->is_name) {
1647 0 : off_t len_idx = j, name_start;
1648 0 : j += 2;
1649 0 : name_start = j;
1650 0 : r = dnsname_to_labels(buf, buf_len, j, item->data, strlen(item->data), &table);
1651 0 : if (r < 0)
1652 0 : goto overflow;
1653 0 : j = r;
1654 0 : _t = htons( (short) (j-name_start) );
1655 0 : memcpy(buf+len_idx, &_t, 2);
1656 : } else {
1657 0 : APPEND16(item->datalen);
1658 0 : if (j+item->datalen > (off_t)buf_len)
1659 0 : goto overflow;
1660 0 : memcpy(buf+j, item->data, item->datalen);
1661 0 : j += item->datalen;
1662 : }
1663 0 : item = item->next;
1664 : }
1665 : }
1666 :
1667 0 : if (j > 512) {
1668 : overflow:
1669 0 : j = 512;
1670 0 : buf[3] |= 0x02; /* set the truncated bit. */
1671 : }
1672 :
1673 0 : req->response_len = j;
1674 :
1675 0 : if (!(req->response = malloc(req->response_len))) {
1676 0 : server_request_free_answers(req);
1677 0 : dnslabel_clear(&table);
1678 0 : return (-1);
1679 : }
1680 0 : memcpy(req->response, buf, req->response_len);
1681 0 : server_request_free_answers(req);
1682 0 : dnslabel_clear(&table);
1683 0 : return (0);
1684 : }
1685 :
1686 : /* exported function */
1687 : int
1688 0 : evdns_server_request_respond(struct evdns_server_request *_req, int err)
1689 : {
1690 0 : struct server_request *req = TO_SERVER_REQUEST(_req);
1691 0 : struct evdns_server_port *port = req->port;
1692 : int r;
1693 0 : if (!req->response) {
1694 0 : if ((r = evdns_server_request_format_response(req, err))<0)
1695 0 : return r;
1696 : }
1697 :
1698 0 : r = sendto(port->socket, req->response, req->response_len, 0,
1699 0 : (struct sockaddr*) &req->addr, req->addrlen);
1700 0 : if (r<0) {
1701 0 : int sock_err = last_error(port->socket);
1702 0 : if (! error_is_eagain(sock_err))
1703 0 : return -1;
1704 :
1705 0 : if (port->pending_replies) {
1706 0 : req->prev_pending = port->pending_replies->prev_pending;
1707 0 : req->next_pending = port->pending_replies;
1708 0 : req->prev_pending->next_pending =
1709 0 : req->next_pending->prev_pending = req;
1710 : } else {
1711 0 : req->prev_pending = req->next_pending = req;
1712 0 : port->pending_replies = req;
1713 0 : port->choked = 1;
1714 :
1715 0 : (void) event_del(&port->event);
1716 0 : event_set(&port->event, port->socket, (port->closing?0:EV_READ) | EV_WRITE | EV_PERSIST, server_port_ready_callback, port);
1717 :
1718 0 : if (event_add(&port->event, NULL) < 0) {
1719 0 : log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server");
1720 : }
1721 :
1722 : }
1723 :
1724 0 : return 1;
1725 : }
1726 0 : if (server_request_free(req))
1727 0 : return 0;
1728 :
1729 0 : if (port->pending_replies)
1730 0 : server_port_flush(port);
1731 :
1732 0 : return 0;
1733 : }
1734 :
1735 : /* Free all storage held by RRs in req. */
1736 : static void
1737 0 : server_request_free_answers(struct server_request *req)
1738 : {
1739 : struct server_reply_item *victim, *next, **list;
1740 : int i;
1741 0 : for (i = 0; i < 3; ++i) {
1742 0 : if (i==0)
1743 0 : list = &req->answer;
1744 0 : else if (i==1)
1745 0 : list = &req->authority;
1746 : else
1747 0 : list = &req->additional;
1748 :
1749 0 : victim = *list;
1750 0 : while (victim) {
1751 0 : next = victim->next;
1752 0 : free(victim->name);
1753 0 : if (victim->data)
1754 0 : free(victim->data);
1755 0 : free(victim);
1756 0 : victim = next;
1757 : }
1758 0 : *list = NULL;
1759 : }
1760 0 : }
1761 :
1762 : /* Free all storage held by req, and remove links to it. */
1763 : /* return true iff we just wound up freeing the server_port. */
1764 : static int
1765 0 : server_request_free(struct server_request *req)
1766 : {
1767 0 : int i, rc=1;
1768 0 : if (req->base.questions) {
1769 0 : for (i = 0; i < req->base.nquestions; ++i)
1770 0 : free(req->base.questions[i]);
1771 0 : free(req->base.questions);
1772 : }
1773 :
1774 0 : if (req->port) {
1775 0 : if (req->port->pending_replies == req) {
1776 0 : if (req->next_pending)
1777 0 : req->port->pending_replies = req->next_pending;
1778 : else
1779 0 : req->port->pending_replies = NULL;
1780 : }
1781 0 : rc = --req->port->refcnt;
1782 : }
1783 :
1784 0 : if (req->response) {
1785 0 : free(req->response);
1786 : }
1787 :
1788 0 : server_request_free_answers(req);
1789 :
1790 0 : if (req->next_pending && req->next_pending != req) {
1791 0 : req->next_pending->prev_pending = req->prev_pending;
1792 0 : req->prev_pending->next_pending = req->next_pending;
1793 : }
1794 :
1795 0 : if (rc == 0) {
1796 0 : server_port_free(req->port);
1797 0 : free(req);
1798 0 : return (1);
1799 : }
1800 0 : free(req);
1801 0 : return (0);
1802 : }
1803 :
1804 : /* Free all storage held by an evdns_server_port. Only called when */
1805 : static void
1806 0 : server_port_free(struct evdns_server_port *port)
1807 : {
1808 0 : assert(port);
1809 0 : assert(!port->refcnt);
1810 0 : assert(!port->pending_replies);
1811 0 : if (port->socket > 0) {
1812 0 : CLOSE_SOCKET(port->socket);
1813 0 : port->socket = -1;
1814 : }
1815 0 : (void) event_del(&port->event);
1816 : /* XXXX actually free the port? -NM */
1817 0 : }
1818 :
1819 : /* exported function */
1820 : int
1821 0 : evdns_server_request_drop(struct evdns_server_request *_req)
1822 : {
1823 0 : struct server_request *req = TO_SERVER_REQUEST(_req);
1824 0 : server_request_free(req);
1825 0 : return 0;
1826 : }
1827 :
1828 : /* exported function */
1829 : int
1830 0 : evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, struct sockaddr *sa, int addr_len)
1831 : {
1832 0 : struct server_request *req = TO_SERVER_REQUEST(_req);
1833 0 : if (addr_len < (int)req->addrlen)
1834 0 : return -1;
1835 0 : memcpy(sa, &(req->addr), req->addrlen);
1836 0 : return req->addrlen;
1837 : }
1838 :
1839 : #undef APPEND16
1840 : #undef APPEND32
1841 :
1842 : /* this is a libevent callback function which is called when a request */
1843 : /* has timed out. */
1844 : static void
1845 0 : evdns_request_timeout_callback(int fd, short events, void *arg) {
1846 0 : struct request *const req = (struct request *) arg;
1847 : (void) fd;
1848 : (void) events;
1849 :
1850 0 : log(EVDNS_LOG_DEBUG, "Request %lx timed out", (unsigned long) arg);
1851 :
1852 0 : req->ns->timedout++;
1853 0 : if (req->ns->timedout > global_max_nameserver_timeout) {
1854 0 : req->ns->timedout = 0;
1855 0 : nameserver_failed(req->ns, "request timed out.");
1856 : }
1857 :
1858 0 : (void) evtimer_del(&req->timeout_event);
1859 0 : if (req->tx_count >= global_max_retransmits) {
1860 : /* this request has failed */
1861 0 : reply_callback(req, 0, DNS_ERR_TIMEOUT, NULL);
1862 0 : request_finished(req, &req_head);
1863 : } else {
1864 : /* retransmit it */
1865 0 : evdns_request_transmit(req);
1866 : }
1867 0 : }
1868 :
1869 : /* try to send a request to a given server. */
1870 : /* */
1871 : /* return: */
1872 : /* 0 ok */
1873 : /* 1 temporary failure */
1874 : /* 2 other failure */
1875 : static int
1876 0 : evdns_request_transmit_to(struct request *req, struct nameserver *server) {
1877 0 : const int r = send(server->socket, req->request, req->request_len, 0);
1878 0 : if (r < 0) {
1879 0 : int err = last_error(server->socket);
1880 0 : if (error_is_eagain(err)) return 1;
1881 0 : nameserver_failed(req->ns, strerror(err));
1882 0 : return 2;
1883 0 : } else if (r != (int)req->request_len) {
1884 0 : return 1; /* short write */
1885 : } else {
1886 0 : return 0;
1887 : }
1888 : }
1889 :
1890 : /* try to send a request, updating the fields of the request */
1891 : /* as needed */
1892 : /* */
1893 : /* return: */
1894 : /* 0 ok */
1895 : /* 1 failed */
1896 : static int
1897 0 : evdns_request_transmit(struct request *req) {
1898 0 : int retcode = 0, r;
1899 :
1900 : /* if we fail to send this packet then this flag marks it */
1901 : /* for evdns_transmit */
1902 0 : req->transmit_me = 1;
1903 0 : if (req->trans_id == 0xffff) abort();
1904 :
1905 0 : if (req->ns->choked) {
1906 : /* don't bother trying to write to a socket */
1907 : /* which we have had EAGAIN from */
1908 0 : return 1;
1909 : }
1910 :
1911 0 : r = evdns_request_transmit_to(req, req->ns);
1912 0 : switch (r) {
1913 : case 1:
1914 : /* temp failure */
1915 0 : req->ns->choked = 1;
1916 0 : nameserver_write_waiting(req->ns, 1);
1917 0 : return 1;
1918 : case 2:
1919 : /* failed in some other way */
1920 0 : retcode = 1;
1921 : /* fall through */
1922 : default:
1923 : /* all ok */
1924 0 : log(EVDNS_LOG_DEBUG,
1925 : "Setting timeout for request %lx", (unsigned long) req);
1926 0 : evtimer_set(&req->timeout_event, evdns_request_timeout_callback, req);
1927 0 : if (evtimer_add(&req->timeout_event, &global_timeout) < 0) {
1928 0 : log(EVDNS_LOG_WARN,
1929 : "Error from libevent when adding timer for request %lx",
1930 : (unsigned long) req);
1931 : /* ???? Do more? */
1932 : }
1933 0 : req->tx_count++;
1934 0 : req->transmit_me = 0;
1935 0 : return retcode;
1936 : }
1937 : }
1938 :
1939 : static void
1940 0 : nameserver_probe_callback(int result, char type, int count, int ttl, void *addresses, void *arg) {
1941 0 : struct nameserver *const ns = (struct nameserver *) arg;
1942 : (void) type;
1943 : (void) count;
1944 : (void) ttl;
1945 : (void) addresses;
1946 :
1947 0 : if (result == DNS_ERR_NONE || result == DNS_ERR_NOTEXIST) {
1948 : /* this is a good reply */
1949 0 : nameserver_up(ns);
1950 0 : } else nameserver_probe_failed(ns);
1951 0 : }
1952 :
1953 : static void
1954 0 : nameserver_send_probe(struct nameserver *const ns) {
1955 : struct request *req;
1956 : /* here we need to send a probe to a given nameserver */
1957 : /* in the hope that it is up now. */
1958 :
1959 0 : log(EVDNS_LOG_DEBUG, "Sending probe to %s", debug_ntoa(ns->address));
1960 :
1961 0 : req = request_new(TYPE_A, "www.google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, ns);
1962 0 : if (!req) return;
1963 : /* we force this into the inflight queue no matter what */
1964 0 : request_trans_id_set(req, transaction_id_pick());
1965 0 : req->ns = ns;
1966 0 : request_submit(req);
1967 : }
1968 :
1969 : /* returns: */
1970 : /* 0 didn't try to transmit anything */
1971 : /* 1 tried to transmit something */
1972 : static int
1973 0 : evdns_transmit(void) {
1974 0 : char did_try_to_transmit = 0;
1975 :
1976 0 : if (req_head) {
1977 0 : struct request *const started_at = req_head, *req = req_head;
1978 : /* first transmit all the requests which are currently waiting */
1979 : do {
1980 0 : if (req->transmit_me) {
1981 0 : did_try_to_transmit = 1;
1982 0 : evdns_request_transmit(req);
1983 : }
1984 :
1985 0 : req = req->next;
1986 0 : } while (req != started_at);
1987 : }
1988 :
1989 0 : return did_try_to_transmit;
1990 : }
1991 :
1992 : /* exported function */
1993 : int
1994 0 : evdns_count_nameservers(void)
1995 : {
1996 0 : const struct nameserver *server = server_head;
1997 0 : int n = 0;
1998 0 : if (!server)
1999 0 : return 0;
2000 : do {
2001 0 : ++n;
2002 0 : server = server->next;
2003 0 : } while (server != server_head);
2004 0 : return n;
2005 : }
2006 :
2007 : /* exported function */
2008 : int
2009 0 : evdns_clear_nameservers_and_suspend(void)
2010 : {
2011 0 : struct nameserver *server = server_head, *started_at = server_head;
2012 0 : struct request *req = req_head, *req_started_at = req_head;
2013 :
2014 0 : if (!server)
2015 0 : return 0;
2016 : while (1) {
2017 0 : struct nameserver *next = server->next;
2018 0 : (void) event_del(&server->event);
2019 0 : if (evtimer_initialized(&server->timeout_event))
2020 0 : (void) evtimer_del(&server->timeout_event);
2021 0 : if (server->socket >= 0)
2022 0 : CLOSE_SOCKET(server->socket);
2023 0 : free(server);
2024 0 : if (next == started_at)
2025 : break;
2026 0 : server = next;
2027 0 : }
2028 0 : server_head = NULL;
2029 0 : global_good_nameservers = 0;
2030 :
2031 0 : while (req) {
2032 0 : struct request *next = req->next;
2033 0 : req->tx_count = req->reissue_count = 0;
2034 0 : req->ns = NULL;
2035 : /* ???? What to do about searches? */
2036 0 : (void) evtimer_del(&req->timeout_event);
2037 0 : req->trans_id = 0;
2038 0 : req->transmit_me = 0;
2039 :
2040 0 : global_requests_waiting++;
2041 0 : evdns_request_insert(req, &req_waiting_head);
2042 : /* We want to insert these suspended elements at the front of
2043 : * the waiting queue, since they were pending before any of
2044 : * the waiting entries were added. This is a circular list,
2045 : * so we can just shift the start back by one.*/
2046 0 : req_waiting_head = req_waiting_head->prev;
2047 :
2048 0 : if (next == req_started_at)
2049 0 : break;
2050 0 : req = next;
2051 : }
2052 0 : req_head = NULL;
2053 0 : global_requests_inflight = 0;
2054 :
2055 0 : return 0;
2056 : }
2057 :
2058 :
2059 : /* exported function */
2060 : int
2061 0 : evdns_resume(void)
2062 : {
2063 0 : evdns_requests_pump_waiting_queue();
2064 0 : return 0;
2065 : }
2066 :
2067 : static int
2068 0 : _evdns_nameserver_add_impl(unsigned long int address, int port) {
2069 : /* first check to see if we already have this nameserver */
2070 :
2071 0 : const struct nameserver *server = server_head, *const started_at = server_head;
2072 : struct nameserver *ns;
2073 : struct sockaddr_in sin;
2074 0 : int err = 0;
2075 0 : if (server) {
2076 : do {
2077 0 : if (server->address == address) return 3;
2078 0 : server = server->next;
2079 0 : } while (server != started_at);
2080 : }
2081 :
2082 0 : ns = (struct nameserver *) malloc(sizeof(struct nameserver));
2083 0 : if (!ns) return -1;
2084 :
2085 0 : memset(ns, 0, sizeof(struct nameserver));
2086 :
2087 0 : ns->socket = socket(PF_INET, SOCK_DGRAM, 0);
2088 0 : if (ns->socket < 0) { err = 1; goto out1; }
2089 0 : evutil_make_socket_nonblocking(ns->socket);
2090 0 : sin.sin_addr.s_addr = address;
2091 0 : sin.sin_port = htons(port);
2092 0 : sin.sin_family = AF_INET;
2093 0 : if (connect(ns->socket, (struct sockaddr *) &sin, sizeof(sin)) != 0) {
2094 0 : err = 2;
2095 0 : goto out2;
2096 : }
2097 :
2098 0 : ns->address = address;
2099 0 : ns->state = 1;
2100 0 : event_set(&ns->event, ns->socket, EV_READ | EV_PERSIST, nameserver_ready_callback, ns);
2101 0 : if (event_add(&ns->event, NULL) < 0) {
2102 0 : err = 2;
2103 0 : goto out2;
2104 : }
2105 :
2106 0 : log(EVDNS_LOG_DEBUG, "Added nameserver %s", debug_ntoa(address));
2107 :
2108 : /* insert this nameserver into the list of them */
2109 0 : if (!server_head) {
2110 0 : ns->next = ns->prev = ns;
2111 0 : server_head = ns;
2112 : } else {
2113 0 : ns->next = server_head->next;
2114 0 : ns->prev = server_head;
2115 0 : server_head->next = ns;
2116 0 : if (server_head->prev == server_head) {
2117 0 : server_head->prev = ns;
2118 : }
2119 : }
2120 :
2121 0 : global_good_nameservers++;
2122 :
2123 0 : return 0;
2124 :
2125 : out2:
2126 0 : CLOSE_SOCKET(ns->socket);
2127 : out1:
2128 0 : free(ns);
2129 0 : log(EVDNS_LOG_WARN, "Unable to add nameserver %s: error %d", debug_ntoa(address), err);
2130 0 : return err;
2131 : }
2132 :
2133 : /* exported function */
2134 : int
2135 0 : evdns_nameserver_add(unsigned long int address) {
2136 0 : return _evdns_nameserver_add_impl(address, 53);
2137 : }
2138 :
2139 : /* exported function */
2140 : int
2141 0 : evdns_nameserver_ip_add(const char *ip_as_string) {
2142 : struct in_addr ina;
2143 : int port;
2144 : char buf[20];
2145 : const char *cp;
2146 0 : cp = strchr(ip_as_string, ':');
2147 0 : if (! cp) {
2148 0 : cp = ip_as_string;
2149 0 : port = 53;
2150 : } else {
2151 0 : port = strtoint(cp+1);
2152 0 : if (port < 0 || port > 65535) {
2153 0 : return 4;
2154 : }
2155 0 : if ((cp-ip_as_string) >= (int)sizeof(buf)) {
2156 0 : return 4;
2157 : }
2158 0 : memcpy(buf, ip_as_string, cp-ip_as_string);
2159 0 : buf[cp-ip_as_string] = '\0';
2160 0 : cp = buf;
2161 : }
2162 0 : if (!inet_aton(cp, &ina)) {
2163 0 : return 4;
2164 : }
2165 0 : return _evdns_nameserver_add_impl(ina.s_addr, port);
2166 : }
2167 :
2168 : /* insert into the tail of the queue */
2169 : static void
2170 0 : evdns_request_insert(struct request *req, struct request **head) {
2171 0 : if (!*head) {
2172 0 : *head = req;
2173 0 : req->next = req->prev = req;
2174 0 : return;
2175 : }
2176 :
2177 0 : req->prev = (*head)->prev;
2178 0 : req->prev->next = req;
2179 0 : req->next = *head;
2180 0 : (*head)->prev = req;
2181 : }
2182 :
2183 : static int
2184 0 : string_num_dots(const char *s) {
2185 0 : int count = 0;
2186 0 : while ((s = strchr(s, '.'))) {
2187 0 : s++;
2188 0 : count++;
2189 : }
2190 0 : return count;
2191 : }
2192 :
2193 : static struct request *
2194 0 : request_new(int type, const char *name, int flags,
2195 : evdns_callback_type callback, void *user_ptr) {
2196 0 : const char issuing_now =
2197 0 : (global_requests_inflight < global_max_requests_inflight) ? 1 : 0;
2198 :
2199 0 : const int name_len = strlen(name);
2200 0 : const int request_max_len = evdns_request_len(name_len);
2201 0 : const u16 trans_id = issuing_now ? transaction_id_pick() : 0xffff;
2202 : /* the request data is alloced in a single block with the header */
2203 0 : struct request *const req =
2204 0 : (struct request *) malloc(sizeof(struct request) + request_max_len);
2205 : int rlen;
2206 : (void) flags;
2207 :
2208 0 : if (!req) return NULL;
2209 0 : memset(req, 0, sizeof(struct request));
2210 :
2211 : /* request data lives just after the header */
2212 0 : req->request = ((u8 *) req) + sizeof(struct request);
2213 : /* denotes that the request data shouldn't be free()ed */
2214 0 : req->request_appended = 1;
2215 0 : rlen = evdns_request_data_build(name, name_len, trans_id,
2216 : type, CLASS_INET, req->request, request_max_len);
2217 0 : if (rlen < 0)
2218 0 : goto err1;
2219 0 : req->request_len = rlen;
2220 0 : req->trans_id = trans_id;
2221 0 : req->tx_count = 0;
2222 0 : req->request_type = type;
2223 0 : req->user_pointer = user_ptr;
2224 0 : req->user_callback = callback;
2225 0 : req->ns = issuing_now ? nameserver_pick() : NULL;
2226 0 : req->next = req->prev = NULL;
2227 :
2228 0 : return req;
2229 : err1:
2230 0 : free(req);
2231 0 : return NULL;
2232 : }
2233 :
2234 : static void
2235 0 : request_submit(struct request *const req) {
2236 0 : if (req->ns) {
2237 : /* if it has a nameserver assigned then this is going */
2238 : /* straight into the inflight queue */
2239 0 : evdns_request_insert(req, &req_head);
2240 0 : global_requests_inflight++;
2241 0 : evdns_request_transmit(req);
2242 : } else {
2243 0 : evdns_request_insert(req, &req_waiting_head);
2244 0 : global_requests_waiting++;
2245 : }
2246 0 : }
2247 :
2248 : /* exported function */
2249 0 : int evdns_resolve_ipv4(const char *name, int flags,
2250 : evdns_callback_type callback, void *ptr) {
2251 0 : log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
2252 0 : if (flags & DNS_QUERY_NO_SEARCH) {
2253 0 : struct request *const req =
2254 : request_new(TYPE_A, name, flags, callback, ptr);
2255 0 : if (req == NULL)
2256 0 : return (1);
2257 0 : request_submit(req);
2258 0 : return (0);
2259 : } else {
2260 0 : return (search_request_new(TYPE_A, name, flags, callback, ptr));
2261 : }
2262 : }
2263 :
2264 : /* exported function */
2265 0 : int evdns_resolve_ipv6(const char *name, int flags,
2266 : evdns_callback_type callback, void *ptr) {
2267 0 : log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
2268 0 : if (flags & DNS_QUERY_NO_SEARCH) {
2269 0 : struct request *const req =
2270 : request_new(TYPE_AAAA, name, flags, callback, ptr);
2271 0 : if (req == NULL)
2272 0 : return (1);
2273 0 : request_submit(req);
2274 0 : return (0);
2275 : } else {
2276 0 : return (search_request_new(TYPE_AAAA, name, flags, callback, ptr));
2277 : }
2278 : }
2279 :
2280 0 : int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
2281 : char buf[32];
2282 : struct request *req;
2283 : u32 a;
2284 0 : assert(in);
2285 0 : a = ntohl(in->s_addr);
2286 0 : evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
2287 0 : (int)(u8)((a )&0xff),
2288 0 : (int)(u8)((a>>8 )&0xff),
2289 0 : (int)(u8)((a>>16)&0xff),
2290 0 : (int)(u8)((a>>24)&0xff));
2291 0 : log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
2292 0 : req = request_new(TYPE_PTR, buf, flags, callback, ptr);
2293 0 : if (!req) return 1;
2294 0 : request_submit(req);
2295 0 : return 0;
2296 : }
2297 :
2298 0 : int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
2299 : /* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
2300 : char buf[73];
2301 : char *cp;
2302 : struct request *req;
2303 : int i;
2304 0 : assert(in);
2305 0 : cp = buf;
2306 0 : for (i=15; i >= 0; --i) {
2307 0 : u8 byte = in->s6_addr[i];
2308 0 : *cp++ = "0123456789abcdef"[byte & 0x0f];
2309 0 : *cp++ = '.';
2310 0 : *cp++ = "0123456789abcdef"[byte >> 4];
2311 0 : *cp++ = '.';
2312 : }
2313 0 : assert(cp + strlen("ip6.arpa") < buf+sizeof(buf));
2314 0 : memcpy(cp, "ip6.arpa", strlen("ip6.arpa")+1);
2315 0 : log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
2316 0 : req = request_new(TYPE_PTR, buf, flags, callback, ptr);
2317 0 : if (!req) return 1;
2318 0 : request_submit(req);
2319 0 : return 0;
2320 : }
2321 :
2322 : /*/////////////////////////////////////////////////////////////////// */
2323 : /* Search support */
2324 : /* */
2325 : /* the libc resolver has support for searching a number of domains */
2326 : /* to find a name. If nothing else then it takes the single domain */
2327 : /* from the gethostname() call. */
2328 : /* */
2329 : /* It can also be configured via the domain and search options in a */
2330 : /* resolv.conf. */
2331 : /* */
2332 : /* The ndots option controls how many dots it takes for the resolver */
2333 : /* to decide that a name is non-local and so try a raw lookup first. */
2334 :
2335 : struct search_domain {
2336 : int len;
2337 : struct search_domain *next;
2338 : /* the text string is appended to this structure */
2339 : };
2340 :
2341 : struct search_state {
2342 : int refcount;
2343 : int ndots;
2344 : int num_domains;
2345 : struct search_domain *head;
2346 : };
2347 :
2348 : static struct search_state *global_search_state = NULL;
2349 :
2350 : static void
2351 0 : search_state_decref(struct search_state *const state) {
2352 0 : if (!state) return;
2353 0 : state->refcount--;
2354 0 : if (!state->refcount) {
2355 : struct search_domain *next, *dom;
2356 0 : for (dom = state->head; dom; dom = next) {
2357 0 : next = dom->next;
2358 0 : free(dom);
2359 : }
2360 0 : free(state);
2361 : }
2362 : }
2363 :
2364 : static struct search_state *
2365 0 : search_state_new(void) {
2366 0 : struct search_state *state = (struct search_state *) malloc(sizeof(struct search_state));
2367 0 : if (!state) return NULL;
2368 0 : memset(state, 0, sizeof(struct search_state));
2369 0 : state->refcount = 1;
2370 0 : state->ndots = 1;
2371 :
2372 0 : return state;
2373 : }
2374 :
2375 : static void
2376 0 : search_postfix_clear(void) {
2377 0 : search_state_decref(global_search_state);
2378 :
2379 0 : global_search_state = search_state_new();
2380 0 : }
2381 :
2382 : /* exported function */
2383 : void
2384 0 : evdns_search_clear(void) {
2385 0 : search_postfix_clear();
2386 0 : }
2387 :
2388 : static void
2389 0 : search_postfix_add(const char *domain) {
2390 : int domain_len;
2391 : struct search_domain *sdomain;
2392 0 : while (domain[0] == '.') domain++;
2393 0 : domain_len = strlen(domain);
2394 :
2395 0 : if (!global_search_state) global_search_state = search_state_new();
2396 0 : if (!global_search_state) return;
2397 0 : global_search_state->num_domains++;
2398 :
2399 0 : sdomain = (struct search_domain *) malloc(sizeof(struct search_domain) + domain_len);
2400 0 : if (!sdomain) return;
2401 0 : memcpy( ((u8 *) sdomain) + sizeof(struct search_domain), domain, domain_len);
2402 0 : sdomain->next = global_search_state->head;
2403 0 : sdomain->len = domain_len;
2404 :
2405 0 : global_search_state->head = sdomain;
2406 : }
2407 :
2408 : /* reverse the order of members in the postfix list. This is needed because, */
2409 : /* when parsing resolv.conf we push elements in the wrong order */
2410 : static void
2411 0 : search_reverse(void) {
2412 0 : struct search_domain *cur, *prev = NULL, *next;
2413 0 : cur = global_search_state->head;
2414 0 : while (cur) {
2415 0 : next = cur->next;
2416 0 : cur->next = prev;
2417 0 : prev = cur;
2418 0 : cur = next;
2419 : }
2420 :
2421 0 : global_search_state->head = prev;
2422 0 : }
2423 :
2424 : /* exported function */
2425 : void
2426 0 : evdns_search_add(const char *domain) {
2427 0 : search_postfix_add(domain);
2428 0 : }
2429 :
2430 : /* exported function */
2431 : void
2432 0 : evdns_search_ndots_set(const int ndots) {
2433 0 : if (!global_search_state) global_search_state = search_state_new();
2434 0 : if (!global_search_state) return;
2435 0 : global_search_state->ndots = ndots;
2436 : }
2437 :
2438 : static void
2439 0 : search_set_from_hostname(void) {
2440 : char hostname[HOST_NAME_MAX + 1], *domainname;
2441 :
2442 0 : search_postfix_clear();
2443 0 : if (gethostname(hostname, sizeof(hostname))) return;
2444 0 : domainname = strchr(hostname, '.');
2445 0 : if (!domainname) return;
2446 0 : search_postfix_add(domainname);
2447 : }
2448 :
2449 : /* warning: returns malloced string */
2450 : static char *
2451 0 : search_make_new(const struct search_state *const state, int n, const char *const base_name) {
2452 0 : const int base_len = strlen(base_name);
2453 0 : const char need_to_append_dot = base_name[base_len - 1] == '.' ? 0 : 1;
2454 : struct search_domain *dom;
2455 :
2456 0 : for (dom = state->head; dom; dom = dom->next) {
2457 0 : if (!n--) {
2458 : /* this is the postfix we want */
2459 : /* the actual postfix string is kept at the end of the structure */
2460 0 : const u8 *const postfix = ((u8 *) dom) + sizeof(struct search_domain);
2461 0 : const int postfix_len = dom->len;
2462 0 : char *const newname = (char *) malloc(base_len + need_to_append_dot + postfix_len + 1);
2463 0 : if (!newname) return NULL;
2464 0 : memcpy(newname, base_name, base_len);
2465 0 : if (need_to_append_dot) newname[base_len] = '.';
2466 0 : memcpy(newname + base_len + need_to_append_dot, postfix, postfix_len);
2467 0 : newname[base_len + need_to_append_dot + postfix_len] = 0;
2468 0 : return newname;
2469 : }
2470 : }
2471 :
2472 : /* we ran off the end of the list and still didn't find the requested string */
2473 0 : abort();
2474 : return NULL; /* unreachable; stops warnings in some compilers. */
2475 : }
2476 :
2477 : static int
2478 0 : search_request_new(int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg) {
2479 0 : assert(type == TYPE_A || type == TYPE_AAAA);
2480 0 : if ( ((flags & DNS_QUERY_NO_SEARCH) == 0) &&
2481 0 : global_search_state &&
2482 0 : global_search_state->num_domains) {
2483 : /* we have some domains to search */
2484 : struct request *req;
2485 0 : if (string_num_dots(name) >= global_search_state->ndots) {
2486 0 : req = request_new(type, name, flags, user_callback, user_arg);
2487 0 : if (!req) return 1;
2488 0 : req->search_index = -1;
2489 : } else {
2490 0 : char *const new_name = search_make_new(global_search_state, 0, name);
2491 0 : if (!new_name) return 1;
2492 0 : req = request_new(type, new_name, flags, user_callback, user_arg);
2493 0 : free(new_name);
2494 0 : if (!req) return 1;
2495 0 : req->search_index = 0;
2496 : }
2497 0 : req->search_origname = strdup(name);
2498 0 : req->search_state = global_search_state;
2499 0 : req->search_flags = flags;
2500 0 : global_search_state->refcount++;
2501 0 : request_submit(req);
2502 0 : return 0;
2503 : } else {
2504 0 : struct request *const req = request_new(type, name, flags, user_callback, user_arg);
2505 0 : if (!req) return 1;
2506 0 : request_submit(req);
2507 0 : return 0;
2508 : }
2509 : }
2510 :
2511 : /* this is called when a request has failed to find a name. We need to check */
2512 : /* if it is part of a search and, if so, try the next name in the list */
2513 : /* returns: */
2514 : /* 0 another request has been submitted */
2515 : /* 1 no more requests needed */
2516 : static int
2517 0 : search_try_next(struct request *const req) {
2518 0 : if (req->search_state) {
2519 : /* it is part of a search */
2520 : char *new_name;
2521 : struct request *newreq;
2522 0 : req->search_index++;
2523 0 : if (req->search_index >= req->search_state->num_domains) {
2524 : /* no more postfixes to try, however we may need to try */
2525 : /* this name without a postfix */
2526 0 : if (string_num_dots(req->search_origname) < req->search_state->ndots) {
2527 : /* yep, we need to try it raw */
2528 0 : newreq = request_new(req->request_type, req->search_origname, req->search_flags, req->user_callback, req->user_pointer);
2529 0 : log(EVDNS_LOG_DEBUG, "Search: trying raw query %s", req->search_origname);
2530 0 : if (newreq) {
2531 0 : request_submit(newreq);
2532 0 : return 0;
2533 : }
2534 : }
2535 0 : return 1;
2536 : }
2537 :
2538 0 : new_name = search_make_new(req->search_state, req->search_index, req->search_origname);
2539 0 : if (!new_name) return 1;
2540 0 : log(EVDNS_LOG_DEBUG, "Search: now trying %s (%d)", new_name, req->search_index);
2541 0 : newreq = request_new(req->request_type, new_name, req->search_flags, req->user_callback, req->user_pointer);
2542 0 : free(new_name);
2543 0 : if (!newreq) return 1;
2544 0 : newreq->search_origname = req->search_origname;
2545 0 : req->search_origname = NULL;
2546 0 : newreq->search_state = req->search_state;
2547 0 : newreq->search_flags = req->search_flags;
2548 0 : newreq->search_index = req->search_index;
2549 0 : newreq->search_state->refcount++;
2550 0 : request_submit(newreq);
2551 0 : return 0;
2552 : }
2553 0 : return 1;
2554 : }
2555 :
2556 : static void
2557 0 : search_request_finished(struct request *const req) {
2558 0 : if (req->search_state) {
2559 0 : search_state_decref(req->search_state);
2560 0 : req->search_state = NULL;
2561 : }
2562 0 : if (req->search_origname) {
2563 0 : free(req->search_origname);
2564 0 : req->search_origname = NULL;
2565 : }
2566 0 : }
2567 :
2568 : /*/////////////////////////////////////////////////////////////////// */
2569 : /* Parsing resolv.conf files */
2570 :
2571 : static void
2572 0 : evdns_resolv_set_defaults(int flags) {
2573 : /* if the file isn't found then we assume a local resolver */
2574 0 : if (flags & DNS_OPTION_SEARCH) search_set_from_hostname();
2575 0 : if (flags & DNS_OPTION_NAMESERVERS) evdns_nameserver_ip_add("127.0.0.1");
2576 0 : }
2577 :
2578 : #ifndef HAVE_STRTOK_R
2579 : static char *
2580 : strtok_r(char *s, const char *delim, char **state) {
2581 : return strtok(s, delim);
2582 : }
2583 : #endif
2584 :
2585 : /* helper version of atoi which returns -1 on error */
2586 : static int
2587 0 : strtoint(const char *const str) {
2588 : char *endptr;
2589 0 : const int r = strtol(str, &endptr, 10);
2590 0 : if (*endptr) return -1;
2591 0 : return r;
2592 : }
2593 :
2594 : /* helper version of atoi that returns -1 on error and clips to bounds. */
2595 : static int
2596 0 : strtoint_clipped(const char *const str, int min, int max)
2597 : {
2598 0 : int r = strtoint(str);
2599 0 : if (r == -1)
2600 0 : return r;
2601 0 : else if (r<min)
2602 0 : return min;
2603 0 : else if (r>max)
2604 0 : return max;
2605 : else
2606 0 : return r;
2607 : }
2608 :
2609 : /* exported function */
2610 : int
2611 0 : evdns_set_option(const char *option, const char *val, int flags)
2612 : {
2613 0 : if (!strncmp(option, "ndots:", 6)) {
2614 0 : const int ndots = strtoint(val);
2615 0 : if (ndots == -1) return -1;
2616 0 : if (!(flags & DNS_OPTION_SEARCH)) return 0;
2617 0 : log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
2618 0 : if (!global_search_state) global_search_state = search_state_new();
2619 0 : if (!global_search_state) return -1;
2620 0 : global_search_state->ndots = ndots;
2621 0 : } else if (!strncmp(option, "timeout:", 8)) {
2622 0 : const int timeout = strtoint(val);
2623 0 : if (timeout == -1) return -1;
2624 0 : if (!(flags & DNS_OPTION_MISC)) return 0;
2625 0 : log(EVDNS_LOG_DEBUG, "Setting timeout to %d", timeout);
2626 0 : global_timeout.tv_sec = timeout;
2627 0 : } else if (!strncmp(option, "max-timeouts:", 12)) {
2628 0 : const int maxtimeout = strtoint_clipped(val, 1, 255);
2629 0 : if (maxtimeout == -1) return -1;
2630 0 : if (!(flags & DNS_OPTION_MISC)) return 0;
2631 0 : log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d",
2632 : maxtimeout);
2633 0 : global_max_nameserver_timeout = maxtimeout;
2634 0 : } else if (!strncmp(option, "max-inflight:", 13)) {
2635 0 : const int maxinflight = strtoint_clipped(val, 1, 65000);
2636 0 : if (maxinflight == -1) return -1;
2637 0 : if (!(flags & DNS_OPTION_MISC)) return 0;
2638 0 : log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d",
2639 : maxinflight);
2640 0 : global_max_requests_inflight = maxinflight;
2641 0 : } else if (!strncmp(option, "attempts:", 9)) {
2642 0 : int retries = strtoint(val);
2643 0 : if (retries == -1) return -1;
2644 0 : if (retries > 255) retries = 255;
2645 0 : if (!(flags & DNS_OPTION_MISC)) return 0;
2646 0 : log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
2647 0 : global_max_retransmits = retries;
2648 : }
2649 0 : return 0;
2650 : }
2651 :
2652 : static void
2653 0 : resolv_conf_parse_line(char *const start, int flags) {
2654 : char *strtok_state;
2655 : static const char *const delims = " \t";
2656 : #define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state)
2657 :
2658 0 : char *const first_token = strtok_r(start, delims, &strtok_state);
2659 0 : if (!first_token) return;
2660 :
2661 0 : if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) {
2662 0 : const char *const nameserver = NEXT_TOKEN;
2663 : struct in_addr ina;
2664 :
2665 0 : if (inet_aton(nameserver, &ina)) {
2666 : /* address is valid */
2667 0 : evdns_nameserver_add(ina.s_addr);
2668 : }
2669 0 : } else if (!strcmp(first_token, "domain") && (flags & DNS_OPTION_SEARCH)) {
2670 0 : const char *const domain = NEXT_TOKEN;
2671 0 : if (domain) {
2672 0 : search_postfix_clear();
2673 0 : search_postfix_add(domain);
2674 : }
2675 0 : } else if (!strcmp(first_token, "search") && (flags & DNS_OPTION_SEARCH)) {
2676 : const char *domain;
2677 0 : search_postfix_clear();
2678 :
2679 0 : while ((domain = NEXT_TOKEN)) {
2680 0 : search_postfix_add(domain);
2681 : }
2682 0 : search_reverse();
2683 0 : } else if (!strcmp(first_token, "options")) {
2684 : const char *option;
2685 0 : while ((option = NEXT_TOKEN)) {
2686 0 : const char *val = strchr(option, ':');
2687 0 : evdns_set_option(option, val ? val+1 : "", flags);
2688 : }
2689 : }
2690 : #undef NEXT_TOKEN
2691 : }
2692 :
2693 : /* exported function */
2694 : /* returns: */
2695 : /* 0 no errors */
2696 : /* 1 failed to open file */
2697 : /* 2 failed to stat file */
2698 : /* 3 file too large */
2699 : /* 4 out of memory */
2700 : /* 5 short read from file */
2701 : int
2702 0 : evdns_resolv_conf_parse(int flags, const char *const filename) {
2703 : struct stat st;
2704 : int fd, n, r;
2705 : u8 *resolv;
2706 : char *start;
2707 0 : int err = 0;
2708 :
2709 0 : log(EVDNS_LOG_DEBUG, "Parsing resolv.conf file %s", filename);
2710 :
2711 0 : fd = open(filename, O_RDONLY);
2712 0 : if (fd < 0) {
2713 0 : evdns_resolv_set_defaults(flags);
2714 0 : return 1;
2715 : }
2716 :
2717 0 : if (fstat(fd, &st)) { err = 2; goto out1; }
2718 0 : if (!st.st_size) {
2719 0 : evdns_resolv_set_defaults(flags);
2720 0 : err = (flags & DNS_OPTION_NAMESERVERS) ? 6 : 0;
2721 0 : goto out1;
2722 : }
2723 0 : if (st.st_size > 65535) { err = 3; goto out1; } /* no resolv.conf should be any bigger */
2724 :
2725 0 : resolv = (u8 *) malloc((size_t)st.st_size + 1);
2726 0 : if (!resolv) { err = 4; goto out1; }
2727 :
2728 0 : n = 0;
2729 0 : while ((r = read(fd, resolv+n, (size_t)st.st_size-n)) > 0) {
2730 0 : n += r;
2731 0 : if (n == st.st_size)
2732 0 : break;
2733 0 : assert(n < st.st_size);
2734 : }
2735 0 : if (r < 0) { err = 5; goto out2; }
2736 0 : resolv[n] = 0; /* we malloced an extra byte; this should be fine. */
2737 :
2738 0 : start = (char *) resolv;
2739 : for (;;) {
2740 0 : char *const newline = strchr(start, '\n');
2741 0 : if (!newline) {
2742 0 : resolv_conf_parse_line(start, flags);
2743 : break;
2744 : } else {
2745 0 : *newline = 0;
2746 0 : resolv_conf_parse_line(start, flags);
2747 0 : start = newline + 1;
2748 : }
2749 0 : }
2750 :
2751 0 : if (!server_head && (flags & DNS_OPTION_NAMESERVERS)) {
2752 : /* no nameservers were configured. */
2753 0 : evdns_nameserver_ip_add("127.0.0.1");
2754 0 : err = 6;
2755 : }
2756 0 : if (flags & DNS_OPTION_SEARCH && (!global_search_state || global_search_state->num_domains == 0)) {
2757 0 : search_set_from_hostname();
2758 : }
2759 :
2760 : out2:
2761 0 : free(resolv);
2762 : out1:
2763 0 : close(fd);
2764 0 : return err;
2765 : }
2766 :
2767 : #ifdef WIN32
2768 : /* Add multiple nameservers from a space-or-comma-separated list. */
2769 : static int
2770 : evdns_nameserver_ip_add_line(const char *ips) {
2771 : const char *addr;
2772 : char *buf;
2773 : int r;
2774 : while (*ips) {
2775 : while (ISSPACE(*ips) || *ips == ',' || *ips == '\t')
2776 : ++ips;
2777 : addr = ips;
2778 : while (ISDIGIT(*ips) || *ips == '.' || *ips == ':')
2779 : ++ips;
2780 : buf = malloc(ips-addr+1);
2781 : if (!buf) return 4;
2782 : memcpy(buf, addr, ips-addr);
2783 : buf[ips-addr] = '\0';
2784 : r = evdns_nameserver_ip_add(buf);
2785 : free(buf);
2786 : if (r) return r;
2787 : }
2788 : return 0;
2789 : }
2790 :
2791 : typedef DWORD(WINAPI *GetNetworkParams_fn_t)(FIXED_INFO *, DWORD*);
2792 :
2793 : /* Use the windows GetNetworkParams interface in iphlpapi.dll to */
2794 : /* figure out what our nameservers are. */
2795 : static int
2796 : load_nameservers_with_getnetworkparams(void)
2797 : {
2798 : /* Based on MSDN examples and inspection of c-ares code. */
2799 : FIXED_INFO *fixed;
2800 : HMODULE handle = 0;
2801 : ULONG size = sizeof(FIXED_INFO);
2802 : void *buf = NULL;
2803 : int status = 0, r, added_any;
2804 : IP_ADDR_STRING *ns;
2805 : GetNetworkParams_fn_t fn;
2806 :
2807 : if (!(handle = LoadLibrary("iphlpapi.dll"))) {
2808 : log(EVDNS_LOG_WARN, "Could not open iphlpapi.dll");
2809 : status = -1;
2810 : goto done;
2811 : }
2812 : if (!(fn = (GetNetworkParams_fn_t) GetProcAddress(handle, "GetNetworkParams"))) {
2813 : log(EVDNS_LOG_WARN, "Could not get address of function.");
2814 : status = -1;
2815 : goto done;
2816 : }
2817 :
2818 : buf = malloc(size);
2819 : if (!buf) { status = 4; goto done; }
2820 : fixed = buf;
2821 : r = fn(fixed, &size);
2822 : if (r != ERROR_SUCCESS && r != ERROR_BUFFER_OVERFLOW) {
2823 : status = -1;
2824 : goto done;
2825 : }
2826 : if (r != ERROR_SUCCESS) {
2827 : free(buf);
2828 : buf = malloc(size);
2829 : if (!buf) { status = 4; goto done; }
2830 : fixed = buf;
2831 : r = fn(fixed, &size);
2832 : if (r != ERROR_SUCCESS) {
2833 : log(EVDNS_LOG_DEBUG, "fn() failed.");
2834 : status = -1;
2835 : goto done;
2836 : }
2837 : }
2838 :
2839 : assert(fixed);
2840 : added_any = 0;
2841 : ns = &(fixed->DnsServerList);
2842 : while (ns) {
2843 : r = evdns_nameserver_ip_add_line(ns->IpAddress.String);
2844 : if (r) {
2845 : log(EVDNS_LOG_DEBUG,"Could not add nameserver %s to list,error: %d",
2846 : (ns->IpAddress.String),(int)GetLastError());
2847 : status = r;
2848 : goto done;
2849 : } else {
2850 : log(EVDNS_LOG_DEBUG,"Succesfully added %s as nameserver",ns->IpAddress.String);
2851 : }
2852 :
2853 : added_any++;
2854 : ns = ns->Next;
2855 : }
2856 :
2857 : if (!added_any) {
2858 : log(EVDNS_LOG_DEBUG, "No nameservers added.");
2859 : status = -1;
2860 : }
2861 :
2862 : done:
2863 : if (buf)
2864 : free(buf);
2865 : if (handle)
2866 : FreeLibrary(handle);
2867 : return status;
2868 : }
2869 :
2870 : static int
2871 : config_nameserver_from_reg_key(HKEY key, const char *subkey)
2872 : {
2873 : char *buf;
2874 : DWORD bufsz = 0, type = 0;
2875 : int status = 0;
2876 :
2877 : if (RegQueryValueEx(key, subkey, 0, &type, NULL, &bufsz)
2878 : != ERROR_MORE_DATA)
2879 : return -1;
2880 : if (!(buf = malloc(bufsz)))
2881 : return -1;
2882 :
2883 : if (RegQueryValueEx(key, subkey, 0, &type, (LPBYTE)buf, &bufsz)
2884 : == ERROR_SUCCESS && bufsz > 1) {
2885 : status = evdns_nameserver_ip_add_line(buf);
2886 : }
2887 :
2888 : free(buf);
2889 : return status;
2890 : }
2891 :
2892 : #define SERVICES_KEY "System\\CurrentControlSet\\Services\\"
2893 : #define WIN_NS_9X_KEY SERVICES_KEY "VxD\\MSTCP"
2894 : #define WIN_NS_NT_KEY SERVICES_KEY "Tcpip\\Parameters"
2895 :
2896 : static int
2897 : load_nameservers_from_registry(void)
2898 : {
2899 : int found = 0;
2900 : int r;
2901 : #define TRY(k, name) \
2902 : if (!found && config_nameserver_from_reg_key(k,name) == 0) { \
2903 : log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \
2904 : found = 1; \
2905 : } else if (!found) { \
2906 : log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \
2907 : #k,#name); \
2908 : }
2909 :
2910 : if (((int)GetVersion()) > 0) { /* NT */
2911 : HKEY nt_key = 0, interfaces_key = 0;
2912 :
2913 : if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
2914 : KEY_READ, &nt_key) != ERROR_SUCCESS) {
2915 : log(EVDNS_LOG_DEBUG,"Couldn't open nt key, %d",(int)GetLastError());
2916 : return -1;
2917 : }
2918 : r = RegOpenKeyEx(nt_key, "Interfaces", 0,
2919 : KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS,
2920 : &interfaces_key);
2921 : if (r != ERROR_SUCCESS) {
2922 : log(EVDNS_LOG_DEBUG,"Couldn't open interfaces key, %d",(int)GetLastError());
2923 : return -1;
2924 : }
2925 : TRY(nt_key, "NameServer");
2926 : TRY(nt_key, "DhcpNameServer");
2927 : TRY(interfaces_key, "NameServer");
2928 : TRY(interfaces_key, "DhcpNameServer");
2929 : RegCloseKey(interfaces_key);
2930 : RegCloseKey(nt_key);
2931 : } else {
2932 : HKEY win_key = 0;
2933 : if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_9X_KEY, 0,
2934 : KEY_READ, &win_key) != ERROR_SUCCESS) {
2935 : log(EVDNS_LOG_DEBUG, "Couldn't open registry key, %d", (int)GetLastError());
2936 : return -1;
2937 : }
2938 : TRY(win_key, "NameServer");
2939 : RegCloseKey(win_key);
2940 : }
2941 :
2942 : if (found == 0) {
2943 : log(EVDNS_LOG_WARN,"Didn't find any nameservers.");
2944 : }
2945 :
2946 : return found ? 0 : -1;
2947 : #undef TRY
2948 : }
2949 :
2950 : static int
2951 : evdns_config_windows_nameservers(void)
2952 : {
2953 : if (load_nameservers_with_getnetworkparams() == 0)
2954 : return 0;
2955 : return load_nameservers_from_registry();
2956 : }
2957 : #endif
2958 :
2959 : int
2960 0 : evdns_init(void)
2961 : {
2962 0 : int res = 0;
2963 : #ifdef WIN32
2964 : res = evdns_config_windows_nameservers();
2965 : #else
2966 0 : res = evdns_resolv_conf_parse(DNS_OPTIONS_ALL, "/etc/resolv.conf");
2967 : #endif
2968 :
2969 0 : return (res);
2970 : }
2971 :
2972 : const char *
2973 0 : evdns_err_to_string(int err)
2974 : {
2975 0 : switch (err) {
2976 0 : case DNS_ERR_NONE: return "no error";
2977 0 : case DNS_ERR_FORMAT: return "misformatted query";
2978 0 : case DNS_ERR_SERVERFAILED: return "server failed";
2979 0 : case DNS_ERR_NOTEXIST: return "name does not exist";
2980 0 : case DNS_ERR_NOTIMPL: return "query not implemented";
2981 0 : case DNS_ERR_REFUSED: return "refused";
2982 :
2983 0 : case DNS_ERR_TRUNCATED: return "reply truncated or ill-formed";
2984 0 : case DNS_ERR_UNKNOWN: return "unknown";
2985 0 : case DNS_ERR_TIMEOUT: return "request timed out";
2986 0 : case DNS_ERR_SHUTDOWN: return "dns subsystem shut down";
2987 0 : default: return "[Unknown error code]";
2988 : }
2989 : }
2990 :
2991 : void
2992 0 : evdns_shutdown(int fail_requests)
2993 : {
2994 : struct nameserver *server, *server_next;
2995 : struct search_domain *dom, *dom_next;
2996 :
2997 0 : while (req_head) {
2998 0 : if (fail_requests)
2999 0 : reply_callback(req_head, 0, DNS_ERR_SHUTDOWN, NULL);
3000 0 : request_finished(req_head, &req_head);
3001 : }
3002 0 : while (req_waiting_head) {
3003 0 : if (fail_requests)
3004 0 : reply_callback(req_waiting_head, 0, DNS_ERR_SHUTDOWN, NULL);
3005 0 : request_finished(req_waiting_head, &req_waiting_head);
3006 : }
3007 0 : global_requests_inflight = global_requests_waiting = 0;
3008 :
3009 0 : for (server = server_head; server; server = server_next) {
3010 0 : server_next = server->next;
3011 0 : if (server->socket >= 0)
3012 0 : CLOSE_SOCKET(server->socket);
3013 0 : (void) event_del(&server->event);
3014 0 : if (server->state == 0)
3015 0 : (void) event_del(&server->timeout_event);
3016 0 : free(server);
3017 0 : if (server_next == server_head)
3018 0 : break;
3019 : }
3020 0 : server_head = NULL;
3021 0 : global_good_nameservers = 0;
3022 :
3023 0 : if (global_search_state) {
3024 0 : for (dom = global_search_state->head; dom; dom = dom_next) {
3025 0 : dom_next = dom->next;
3026 0 : free(dom);
3027 : }
3028 0 : free(global_search_state);
3029 0 : global_search_state = NULL;
3030 : }
3031 0 : evdns_log_fn = NULL;
3032 0 : }
3033 :
3034 : #ifdef EVDNS_MAIN
3035 : void
3036 : main_callback(int result, char type, int count, int ttl,
3037 : void *addrs, void *orig) {
3038 : char *n = (char*)orig;
3039 : int i;
3040 : for (i = 0; i < count; ++i) {
3041 : if (type == DNS_IPv4_A) {
3042 : printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i]));
3043 : } else if (type == DNS_PTR) {
3044 : printf("%s: %s\n", n, ((char**)addrs)[i]);
3045 : }
3046 : }
3047 : if (!count) {
3048 : printf("%s: No answer (%d)\n", n, result);
3049 : }
3050 : fflush(stdout);
3051 : }
3052 : void
3053 : evdns_server_callback(struct evdns_server_request *req, void *data)
3054 : {
3055 : int i, r;
3056 : (void)data;
3057 : /* dummy; give 192.168.11.11 as an answer for all A questions,
3058 : * give foo.bar.example.com as an answer for all PTR questions. */
3059 : for (i = 0; i < req->nquestions; ++i) {
3060 : u32 ans = htonl(0xc0a80b0bUL);
3061 : if (req->questions[i]->type == EVDNS_TYPE_A &&
3062 : req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
3063 : printf(" -- replying for %s (A)\n", req->questions[i]->name);
3064 : r = evdns_server_request_add_a_reply(req, req->questions[i]->name,
3065 : 1, &ans, 10);
3066 : if (r<0)
3067 : printf("eeep, didn't work.\n");
3068 : } else if (req->questions[i]->type == EVDNS_TYPE_PTR &&
3069 : req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
3070 : printf(" -- replying for %s (PTR)\n", req->questions[i]->name);
3071 : r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name,
3072 : "foo.bar.example.com", 10);
3073 : } else {
3074 : printf(" -- skipping %s [%d %d]\n", req->questions[i]->name,
3075 : req->questions[i]->type, req->questions[i]->dns_question_class);
3076 : }
3077 : }
3078 :
3079 : r = evdns_request_respond(req, 0);
3080 : if (r<0)
3081 : printf("eeek, couldn't send reply.\n");
3082 : }
3083 :
3084 : void
3085 : logfn(int is_warn, const char *msg) {
3086 : (void) is_warn;
3087 : fprintf(stderr, "%s\n", msg);
3088 : }
3089 : int
3090 : main(int c, char **v) {
3091 : int idx;
3092 : int reverse = 0, verbose = 1, servertest = 0;
3093 : if (c<2) {
3094 : fprintf(stderr, "syntax: %s [-x] [-v] hostname\n", v[0]);
3095 : fprintf(stderr, "syntax: %s [-servertest]\n", v[0]);
3096 : return 1;
3097 : }
3098 : idx = 1;
3099 : while (idx < c && v[idx][0] == '-') {
3100 : if (!strcmp(v[idx], "-x"))
3101 : reverse = 1;
3102 : else if (!strcmp(v[idx], "-v"))
3103 : verbose = 1;
3104 : else if (!strcmp(v[idx], "-servertest"))
3105 : servertest = 1;
3106 : else
3107 : fprintf(stderr, "Unknown option %s\n", v[idx]);
3108 : ++idx;
3109 : }
3110 : event_init();
3111 : if (verbose)
3112 : evdns_set_log_fn(logfn);
3113 : evdns_resolv_conf_parse(DNS_OPTION_NAMESERVERS, "/etc/resolv.conf");
3114 : if (servertest) {
3115 : int sock;
3116 : struct sockaddr_in my_addr;
3117 : sock = socket(PF_INET, SOCK_DGRAM, 0);
3118 : evutil_make_socket_nonblocking(sock);
3119 : my_addr.sin_family = AF_INET;
3120 : my_addr.sin_port = htons(10053);
3121 : my_addr.sin_addr.s_addr = INADDR_ANY;
3122 : if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) {
3123 : perror("bind");
3124 : exit(1);
3125 : }
3126 : evdns_add_server_port(sock, 0, evdns_server_callback, NULL);
3127 : }
3128 : for (; idx < c; ++idx) {
3129 : if (reverse) {
3130 : struct in_addr addr;
3131 : if (!inet_aton(v[idx], &addr)) {
3132 : fprintf(stderr, "Skipping non-IP %s\n", v[idx]);
3133 : continue;
3134 : }
3135 : fprintf(stderr, "resolving %s...\n",v[idx]);
3136 : evdns_resolve_reverse(&addr, 0, main_callback, v[idx]);
3137 : } else {
3138 : fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
3139 : evdns_resolve_ipv4(v[idx], 0, main_callback, v[idx]);
3140 : }
3141 : }
3142 : fflush(stdout);
3143 : event_dispatch();
3144 : return 0;
3145 : }
3146 : #endif
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