1 /* The original version of this module was written by Adam Langley; for
2 * a history of modifications, check out the subversion logs.
4 * When editing this module, try to keep it re-mergeable by Adam. Don't
5 * reformat the whitespace, add Tor dependencies, or so on.
8 * - Replace all externally visible magic numbers with #defined constants.
9 * - Write documentation for APIs of all external functions.
13 * Adam Langley <agl@imperialviolet.org>
16 * This software is Public Domain. To view a copy of the public domain dedication,
17 * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
18 * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
20 * I ask and expect, but do not require, that all derivative works contain an
21 * attribution similar to:
22 * Parts developed by Adam Langley <agl@imperialviolet.org>
24 * You may wish to replace the word "Parts" with something else depending on
25 * the amount of original code.
27 * (Derivative works does not include programs which link against, run or include
28 * the source verbatim in their source distributions)
33 #include "eventdns_tor.h"
34 #include "../common/util.h"
35 #include <sys/types.h>
38 #ifndef DNS_USE_CPU_CLOCK_FOR_ID
39 #ifndef DNS_USE_GETTIMEOFDAY_FOR_ID
40 #ifndef DNS_USE_OPENSSL_FOR_ID
41 #error Must configure at least one id generation method.
42 #error Please see the documentation.
47 /* #define _POSIX_C_SOURCE 200507 */
50 #ifdef DNS_USE_CPU_CLOCK_FOR_ID
51 #ifdef DNS_USE_OPENSSL_FOR_ID
52 #error Multiple id options selected
54 #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
55 #error Multiple id options selected
60 #ifdef DNS_USE_OPENSSL_FOR_ID
61 #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
62 #error Multiple id options selected
64 #include <openssl/rand.h>
71 #ifdef HAVE_SYS_TIME_H
99 #include <sys/socket.h>
100 #include <netinet/in.h>
101 #include <arpa/inet.h>
104 #ifdef HAVE_NETINET_IN6_H
105 #include <netinet/in6.h>
109 typedef int socklen_t
;
112 #define EVDNS_LOG_DEBUG 0
113 #define EVDNS_LOG_WARN 1
115 #ifndef HOST_NAME_MAX
116 #define HOST_NAME_MAX 255
123 /* for debugging possible memory leaks. */
124 #define mm_malloc(x) tor_malloc(x)
125 #define mm_realloc(x,y) tor_realloc((x),(y))
126 #define mm_free(x) tor_free(x)
127 #define mm_strdup(x) tor_strdup(x)
128 #define _mm_free(x) _tor_free(x)
131 #define MIN(a,b) ((a)<(b)?(a):(b))
135 /* libevent doesn't work without this */
136 typedef uint8_t u_char
;
137 typedef unsigned int uint
;
147 #define MAX_ADDRS 4 /* maximum number of addresses from a single packet */
148 /* which we bother recording */
150 #define TYPE_A EVDNS_TYPE_A
152 #define TYPE_PTR EVDNS_TYPE_PTR
153 #define TYPE_AAAA EVDNS_TYPE_AAAA
155 #define CLASS_INET EVDNS_CLASS_INET
157 #define CLEAR(x) do { memset((x), 0xF0, sizeof(*(x))); } while(0)
159 struct evdns_request
{
160 u8
*request
; /* the dns packet data */
161 unsigned int request_len
;
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 */
169 /* elements used by the searching code */
171 struct search_state
*search_state
;
172 char *search_origname
; /* needs to be mm_free()ed */
175 /* these objects are kept in a circular list */
176 struct evdns_request
*next
, *prev
;
178 struct event timeout_event
;
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 */
185 #ifndef HAVE_STRUCT_IN6_ADDR
193 unsigned int have_answer
;
197 u32 addresses
[MAX_ADDRS
];
201 struct in6_addr addresses
[MAX_ADDRS
];
204 char name
[HOST_NAME_MAX
];
210 int socket
; /* a connected UDP socket */
211 struct sockaddr_storage 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 */
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 */
225 static struct evdns_request
*req_head
= NULL
, *req_waiting_head
= NULL
;
226 static struct nameserver
*server_head
= NULL
;
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
;
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 */
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
;
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 */
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? */
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 */
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. */
281 /* Caller-visible fields: flags, questions. */
282 struct evdns_server_request base
;
286 #define OFFSET_OF(st, member) ((off_t) (((char*)&((st*)0)->member)-(char*)0))
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))))
294 /* The number of good nameservers that we have */
295 static int global_good_nameservers
= 0;
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;
304 static int global_max_requests_inflight
= 64;
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;
312 /* true iff we should use the 0x20 hack. */
313 static int global_randomize_case
= 1;
315 /* These are the timeout values for nameservers. If we find a nameserver is down */
316 /* we try to probe it at intervals as given below. Values are in seconds. */
317 static const struct timeval global_nameserver_timeouts
[] = {{10, 0}, {60, 0}, {300, 0}, {900, 0}, {3600, 0}};
318 static const int global_nameserver_timeouts_length
= (int)(sizeof(global_nameserver_timeouts
)/sizeof(struct timeval
));
320 static struct nameserver
*nameserver_pick(void);
321 static void evdns_request_insert(struct evdns_request
*req
, struct evdns_request
**head
);
322 static void nameserver_ready_callback(int fd
, short events
, void *arg
);
323 static int evdns_transmit(void);
324 static int evdns_request_transmit(struct evdns_request
*req
);
325 static void nameserver_send_probe(struct nameserver
*const ns
);
326 static void search_request_finished(struct evdns_request
*const);
327 static int search_try_next(struct evdns_request
*const req
);
328 static int search_request_new(int type
, const char *const name
, int flags
, evdns_callback_type user_callback
, void *user_arg
);
329 static void evdns_requests_pump_waiting_queue(void);
330 static u16
transaction_id_pick(void);
331 static struct evdns_request
*request_new(int type
, const char *name
, int flags
, evdns_callback_type callback
, void *ptr
);
332 static void request_submit(struct evdns_request
*req
);
334 static int server_request_free(struct server_request
*req
);
335 static void server_request_free_answers(struct server_request
*req
);
336 static void server_port_free(struct evdns_server_port
*port
);
337 static void server_port_ready_callback(int fd
, short events
, void *arg
);
339 static int strtoint(const char *const str
);
345 int optval
, optvallen
=sizeof(optval
);
346 int err
= WSAGetLastError();
347 if (err
== WSAEWOULDBLOCK
&& sock
>= 0) {
348 if (getsockopt(sock
, SOL_SOCKET
, SO_ERROR
, (void*)&optval
,
358 error_is_eagain(int err
)
360 return err
== EAGAIN
|| err
== WSAEWOULDBLOCK
;
362 #define inet_aton(c, addr) tor_inet_aton((c), (addr))
363 #define CLOSE_SOCKET(x) closesocket(x)
365 #define last_error(sock) (errno)
366 #define error_is_eagain(err) ((err) == EAGAIN)
367 #define CLOSE_SOCKET(x) close(x)
370 #define ISSPACE(c) TOR_ISSPACE(c)
371 #define ISDIGIT(c) TOR_ISDIGIT(c)
372 #define ISALPHA(c) TOR_ISALPHA(c)
373 #define TOLOWER(c) TOR_TOLOWER(c)
374 #define TOUPPER(c) TOR_TOUPPER(c)
378 debug_ntoa(u32 address
)
381 u32 a
= ntohl(address
);
382 snprintf(buf
, sizeof(buf
), "%d.%d.%d.%d",
383 (int)(u8
)((a
>>24)&0xff),
384 (int)(u8
)((a
>>16)&0xff),
385 (int)(u8
)((a
>>8 )&0xff),
386 (int)(u8
)((a
)&0xff));
390 debug_ntop(const struct sockaddr
*sa
)
392 if (sa
->sa_family
== AF_INET
) {
393 struct sockaddr_in
*sin
= (struct sockaddr_in
*) sa
;
394 return debug_ntoa(sin
->sin_addr
.s_addr
);
396 if (sa
->sa_family
== AF_INET6
) {
397 /* Tor-specific. In libevent, add more check code. */
398 static char buf
[128];
399 struct sockaddr_in6
*sin
= (struct sockaddr_in6
*) sa
;
400 tor_inet_ntop(AF_INET6
, &sin
->sin6_addr
, buf
, sizeof(buf
));
407 static evdns_debug_log_fn_type evdns_log_fn
= NULL
;
410 evdns_set_log_fn(evdns_debug_log_fn_type fn
)
416 #define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3)))
418 #define EVDNS_LOG_CHECK
421 static void _evdns_log(int warn
, const char *fmt
, ...) EVDNS_LOG_CHECK
;
423 _evdns_log(int warn
, const char *fmt
, ...)
426 static char buf
[512];
431 _vsnprintf(buf
, sizeof(buf
), fmt
, args
);
433 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
435 buf
[sizeof(buf
)-1] = '\0';
436 evdns_log_fn(warn
, buf
);
440 #define log _evdns_log
443 sockaddr_eq(const struct sockaddr
*sa1
, const struct sockaddr
*sa2
,
446 if (sa1
->sa_family
!= sa2
->sa_family
)
448 if (sa1
->sa_family
== AF_INET
) {
449 const struct sockaddr_in
*sin1
, *sin2
;
450 sin1
= (const struct sockaddr_in
*)sa1
;
451 sin2
= (const struct sockaddr_in
*)sa2
;
452 if (sin1
->sin_addr
.s_addr
!= sin2
->sin_addr
.s_addr
)
454 else if (include_port
&& sin1
->sin_port
!= sin2
->sin_port
)
460 if (sa1
->sa_family
== AF_INET6
) {
461 const struct sockaddr_in6
*sin1
, *sin2
;
462 sin1
= (const struct sockaddr_in6
*)sa1
;
463 sin2
= (const struct sockaddr_in6
*)sa2
;
464 if (memcmp(sin1
->sin6_addr
.s6_addr
, sin2
->sin6_addr
.s6_addr
, 16))
466 else if (include_port
&& sin1
->sin6_port
!= sin2
->sin6_port
)
475 #define add_timeout_event(s, to) \
476 (event_add(&(s)->timeout_event, (to)))
477 #define del_timeout_event(s) \
478 (event_del(&(s)->timeout_event))
480 /* This walks the list of inflight requests to find the */
481 /* one with a matching transaction id. Returns NULL on */
483 static struct evdns_request
*
484 request_find_from_trans_id(u16 trans_id
) {
485 struct evdns_request
*req
= req_head
, *const started_at
= req_head
;
489 if (req
->trans_id
== trans_id
) return req
;
491 } while (req
!= started_at
);
497 /* a libevent callback function which is called when a nameserver */
498 /* has gone down and we want to test if it has came back to life yet */
500 nameserver_prod_callback(int fd
, short events
, void *arg
) {
501 struct nameserver
*const ns
= (struct nameserver
*) arg
;
505 nameserver_send_probe(ns
);
508 /* a libevent callback which is called when a nameserver probe (to see if */
509 /* it has come back to life) times out. We increment the count of failed_times */
510 /* and wait longer to send the next probe packet. */
512 nameserver_probe_failed(struct nameserver
*const ns
) {
513 const struct timeval
* timeout
;
514 del_timeout_event(ns
);
516 if (ns
->state
== 1) {
517 /* This can happen if the nameserver acts in a way which makes us mark */
518 /* it as bad and then starts sending good replies. */
523 &global_nameserver_timeouts
[MIN(ns
->failed_times
,
524 global_nameserver_timeouts_length
- 1)];
527 if (add_timeout_event(ns
, (struct timeval
*) timeout
) < 0) {
529 "Error from libevent when adding timer event for %s",
530 debug_ntop((struct sockaddr
*)&ns
->address
));
535 /* called when a nameserver has been deemed to have failed. For example, too */
536 /* many packets have timed out etc */
538 nameserver_failed(struct nameserver
*const ns
, const char *msg
) {
539 struct evdns_request
*req
, *started_at
;
540 /* if this nameserver has already been marked as failed */
541 /* then don't do anything */
542 if (!ns
->state
) return;
544 log(EVDNS_LOG_WARN
, "Nameserver %s has failed: %s",
545 debug_ntop((struct sockaddr
*)&ns
->address
), msg
);
546 global_good_nameservers
--;
547 assert(global_good_nameservers
>= 0);
548 if (global_good_nameservers
== 0) {
549 log(EVDNS_LOG_WARN
, "All nameservers have failed");
553 ns
->failed_times
= 1;
555 if (add_timeout_event(ns
, (struct timeval
*) &global_nameserver_timeouts
[0]) < 0) {
557 "Error from libevent when adding timer event for %s",
558 debug_ntop((struct sockaddr
*)&ns
->address
));
562 /* walk the list of inflight requests to see if any can be reassigned to */
563 /* a different server. Requests in the waiting queue don't have a */
564 /* nameserver assigned yet */
566 /* if we don't have *any* good nameservers then there's no point */
567 /* trying to reassign requests to one */
568 if (!global_good_nameservers
) return;
571 started_at
= req_head
;
574 if (req
->tx_count
== 0 && req
->ns
== ns
) {
575 /* still waiting to go out, can be moved */
576 /* to another server */
577 req
->ns
= nameserver_pick();
580 } while (req
!= started_at
);
585 nameserver_up(struct nameserver
*const ns
) {
586 if (ns
->state
) return;
587 log(EVDNS_LOG_WARN
, "Nameserver %s is back up",
588 debug_ntop((struct sockaddr
*)&ns
->address
));
589 del_timeout_event(ns
);
591 ns
->failed_times
= 0;
593 global_good_nameservers
++;
597 request_trans_id_set(struct evdns_request
*const req
, const u16 trans_id
) {
598 req
->trans_id
= trans_id
;
599 *((u16
*) req
->request
) = htons(trans_id
);
602 /* Called to remove a request from a list and dealloc it. */
603 /* head is a pointer to the head of the list it should be */
604 /* removed from or NULL if the request isn't in a list. */
606 request_finished(struct evdns_request
*const req
, struct evdns_request
**head
) {
608 if (req
->next
== req
) {
609 /* only item in the list */
612 req
->next
->prev
= req
->prev
;
613 req
->prev
->next
= req
->next
;
614 if (*head
== req
) *head
= req
->next
;
618 log(EVDNS_LOG_DEBUG
, "Removing timeout for request %lx",
619 (unsigned long) req
);
620 del_timeout_event(req
);
622 search_request_finished(req
);
623 global_requests_inflight
--;
625 if (!req
->request_appended
) {
626 /* need to free the request data on it's own */
627 mm_free(req
->request
);
629 /* the request data is appended onto the header */
630 /* so everything gets mm_free()ed when we: */
636 evdns_requests_pump_waiting_queue();
639 /* This is called when a server returns a funny error code. */
640 /* We try the request again with another server. */
644 /* 1 failed/reissue is pointless */
646 request_reissue(struct evdns_request
*req
) {
647 const struct nameserver
*const last_ns
= req
->ns
;
648 /* the last nameserver should have been marked as failing */
649 /* by the caller of this function, therefore pick will try */
650 /* not to return it */
651 req
->ns
= nameserver_pick();
652 if (req
->ns
== last_ns
) {
653 /* ... but pick did return it */
654 /* not a lot of point in trying again with the */
659 req
->reissue_count
++;
661 req
->transmit_me
= 1;
666 /* this function looks for space on the inflight queue and promotes */
667 /* requests from the waiting queue if it can. */
669 evdns_requests_pump_waiting_queue(void) {
670 while (global_requests_inflight
< global_max_requests_inflight
&&
671 global_requests_waiting
) {
672 struct evdns_request
*req
;
673 /* move a request from the waiting queue to the inflight queue */
674 assert(req_waiting_head
);
675 if (req_waiting_head
->next
== req_waiting_head
) {
676 /* only one item in the queue */
677 req
= req_waiting_head
;
678 req_waiting_head
= NULL
;
680 req
= req_waiting_head
;
681 req
->next
->prev
= req
->prev
;
682 req
->prev
->next
= req
->next
;
683 req_waiting_head
= req
->next
;
686 global_requests_waiting
--;
687 global_requests_inflight
++;
689 req
->ns
= nameserver_pick();
690 request_trans_id_set(req
, transaction_id_pick());
692 evdns_request_insert(req
, &req_head
);
693 evdns_request_transmit(req
);
699 reply_callback(struct evdns_request
*const req
, u32 ttl
, u32 err
, struct reply
*reply
) {
700 switch (req
->request_type
) {
703 req
->user_callback(DNS_ERR_NONE
, DNS_IPv4_A
,
704 reply
->data
.a
.addrcount
, ttl
,
705 reply
->data
.a
.addresses
,
708 req
->user_callback(err
, 0, 0, 0, NULL
, req
->user_pointer
);
712 char *name
= reply
->data
.ptr
.name
;
713 req
->user_callback(DNS_ERR_NONE
, DNS_PTR
, 1, ttl
,
714 &name
, req
->user_pointer
);
716 req
->user_callback(err
, 0, 0, 0, NULL
,
722 req
->user_callback(DNS_ERR_NONE
, DNS_IPv6_AAAA
,
723 reply
->data
.aaaa
.addrcount
, ttl
,
724 reply
->data
.aaaa
.addresses
,
727 req
->user_callback(err
, 0, 0, 0, NULL
, req
->user_pointer
);
733 /* this processes a parsed reply packet */
735 reply_handle(struct evdns_request
*const req
, u16 flags
, u32 ttl
, struct reply
*reply
) {
737 static const int error_codes
[] = {DNS_ERR_FORMAT
, DNS_ERR_SERVERFAILED
, DNS_ERR_NOTEXIST
, DNS_ERR_NOTIMPL
, DNS_ERR_REFUSED
};
739 if (flags
& 0x020f || !reply
|| !reply
->have_answer
) {
740 /* there was an error */
741 if (flags
& 0x0200) {
742 error
= DNS_ERR_TRUNCATED
;
744 u16 error_code
= (flags
& 0x000f) - 1;
745 if (error_code
> 4) {
746 error
= DNS_ERR_UNKNOWN
;
748 error
= error_codes
[error_code
];
753 case DNS_ERR_NOTIMPL
:
754 case DNS_ERR_REFUSED
:
755 /* we regard these errors as marking a bad nameserver */
756 if (req
->reissue_count
< global_max_reissues
) {
758 snprintf(msg
, sizeof(msg
), "Bad response %d (%s)",
759 error
, evdns_err_to_string(error
));
760 nameserver_failed(req
->ns
, msg
);
761 if (!request_reissue(req
)) return;
764 case DNS_ERR_SERVERFAILED
:
765 /* rcode 2 (servfailed) sometimes means "we are broken" and
766 * sometimes (with some binds) means "that request was very
767 * confusing." Treat this as a timeout, not a failure.
769 /*XXXX refactor the parts of */
770 log(EVDNS_LOG_DEBUG
, "Got a SERVERFAILED from nameserver %s; "
771 "will allow the request to time out.",
772 debug_ntop((struct sockaddr
*)&req
->ns
->address
));
775 /* we got a good reply from the nameserver */
776 nameserver_up(req
->ns
);
779 if (req
->search_state
&& req
->request_type
!= TYPE_PTR
) {
780 /* if we have a list of domains to search in, try the next one */
781 if (!search_try_next(req
)) {
782 /* a new request was issued so this request is finished and */
783 /* the user callback will be made when that request (or a */
784 /* child of it) finishes. */
785 request_finished(req
, &req_head
);
790 /* all else failed. Pass the failure up */
791 reply_callback(req
, 0, error
, NULL
);
792 request_finished(req
, &req_head
);
794 /* all ok, tell the user */
795 reply_callback(req
, ttl
, 0, reply
);
796 nameserver_up(req
->ns
);
797 request_finished(req
, &req_head
);
802 name_parse(u8
*packet
, int length
, int *idx
, char *name_out
, size_t name_out_len
) {
806 #define GET32(x) do { if (j + 4 > length) goto err; memcpy(&_t32, packet + j, 4); j += 4; x = ntohl(_t32); } while(0)
807 #define GET16(x) do { if (j + 2 > length) goto err; memcpy(&_t, packet + j, 2); j += 2; x = ntohs(_t); } while(0)
808 #define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while(0)
811 const char *const end
= name_out
+ name_out_len
;
813 /* Normally, names are a series of length prefixed strings terminated */
814 /* with a length of 0 (the lengths are u8's < 63). */
815 /* However, the length can start with a pair of 1 bits and that */
816 /* means that the next 14 bits are a pointer within the current */
821 if (j
>= length
) return -1;
823 if (!label_len
) break;
824 if (label_len
& 0xc0) {
827 if (name_end
< 0) name_end
= j
;
828 j
= (((int)label_len
& 0x3f) << 8) + ptr_low
;
829 /* Make sure that the target offset is in-bounds. */
830 if (j
< 0 || j
>= length
) return -1;
831 /* If we've jumped more times than there are characters in the
832 * message, we must have a loop. */
833 if (++ptr_count
> length
) return -1;
836 if (label_len
> 63) return -1;
837 if (cp
!= name_out
) {
838 if (cp
+ 1 >= end
) return -1;
841 if (cp
+ label_len
>= end
) return -1;
842 memcpy(cp
, packet
+ j
, label_len
);
846 if (cp
>= end
) return -1;
857 /* parses a raw reply from a nameserver. */
859 reply_parse(u8
*packet
, int length
) {
860 int j
= 0; /* index into packet */
862 u16 _t
; /* used by the macros */
863 u32 _t32
; /* used by the macros */
864 char tmp_name
[256], cmp_name
[256]; /* used by the macros */
866 u16 trans_id
, questions
, answers
, authority
, additional
, datalength
;
868 u32 ttl
, ttl_r
= 0xffffffff;
870 struct evdns_request
*req
= NULL
;
872 int name_matches
= 0;
880 (void) authority
; /* suppress "unused variable" warnings. */
881 (void) additional
; /* suppress "unused variable" warnings. */
883 req
= request_find_from_trans_id(trans_id
);
884 /* if no request, can't do anything. */
887 memset(&reply
, 0, sizeof(reply
));
889 /* If it's not an answer, it doesn't go with any of our requests. */
890 if (!(flags
& 0x8000)) return -1; /* must be an answer */
891 if (flags
& 0x020f) {
892 /* there was an error */
895 /* if (!answers) return; */ /* must have an answer of some form */
897 /* This macro skips a name in the DNS reply. */
899 do { tmp_name[0] = '\0'; \
900 if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
904 do { tmp_name[0] = '\0'; \
905 cmp_name[0] = '\0'; \
907 if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
909 if (name_parse(req->request, req->request_len, &k, cmp_name, sizeof(cmp_name))<0) \
911 if (global_randomize_case) { \
912 if (strcmp(tmp_name, cmp_name) == 0) \
913 name_matches = 1; /* we ignore mismatching names */ \
915 if (strcasecmp(tmp_name, cmp_name) == 0) \
920 reply
.type
= req
->request_type
;
922 /* skip over each question in the reply */
923 for (i
= 0; i
< questions
; ++i
) {
924 /* the question looks like
925 * <label:name><u16:type><u16:class>
929 if (j
>= length
) goto err
;
935 /* now we have the answer section which looks like
936 * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
939 for (i
= 0; i
< answers
; ++i
) {
948 if (type
== TYPE_A
&& class == CLASS_INET
) {
949 int addrcount
, addrtocopy
;
950 if (req
->request_type
!= TYPE_A
) {
951 j
+= datalength
; continue;
953 if ((datalength
& 3) != 0) /* not an even number of As. */
955 addrcount
= datalength
>> 2;
956 addrtocopy
= MIN(MAX_ADDRS
- reply
.data
.a
.addrcount
, (unsigned)addrcount
);
958 ttl_r
= MIN(ttl_r
, ttl
);
959 /* we only bother with the first four addresses. */
960 if (j
+ 4*addrtocopy
> length
) goto err
;
961 memcpy(&reply
.data
.a
.addresses
[reply
.data
.a
.addrcount
],
962 packet
+ j
, 4*addrtocopy
);
963 reply
.data
.a
.addrcount
+= addrtocopy
;
964 reply
.have_answer
= 1;
965 if (reply
.data
.a
.addrcount
== MAX_ADDRS
) break;
967 } else if (type
== TYPE_PTR
&& class == CLASS_INET
) {
968 if (req
->request_type
!= TYPE_PTR
) {
969 j
+= datalength
; continue;
972 strlcpy(reply
.data
.ptr
.name
, tmp_name
,
973 sizeof(reply
.data
.ptr
.name
));
974 ttl_r
= MIN(ttl_r
, ttl
);
975 reply
.have_answer
= 1;
977 } else if (type
== TYPE_AAAA
&& class == CLASS_INET
) {
978 int addrcount
, addrtocopy
;
979 if (req
->request_type
!= TYPE_AAAA
) {
980 j
+= datalength
; continue;
982 if ((datalength
& 15) != 0) /* not an even number of AAAAs. */
984 addrcount
= datalength
>> 4; /* each address is 16 bytes long */
985 addrtocopy
= MIN(MAX_ADDRS
- reply
.data
.aaaa
.addrcount
, (unsigned)addrcount
);
986 ttl_r
= MIN(ttl_r
, ttl
);
988 /* we only bother with the first four addresses. */
989 if (j
+ 16*addrtocopy
> length
) goto err
;
990 memcpy(&reply
.data
.aaaa
.addresses
[reply
.data
.aaaa
.addrcount
],
991 packet
+ j
, 16*addrtocopy
);
992 reply
.data
.aaaa
.addrcount
+= addrtocopy
;
993 reply
.have_answer
= 1;
994 if (reply
.data
.aaaa
.addrcount
== MAX_ADDRS
) break;
997 /* skip over any other type of resource */
1002 reply_handle(req
, flags
, ttl_r
, &reply
);
1006 reply_handle(req
, flags
, 0, NULL
);
1010 /* Parse a raw request (packet,length) sent to a nameserver port (port) from */
1011 /* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
1014 request_parse(u8
*packet
, ssize_t length
, struct evdns_server_port
*port
, struct sockaddr
*addr
, socklen_t addrlen
)
1016 int j
= 0; /* index into packet */
1017 u16 _t
; /* used by the macros */
1018 char tmp_name
[256]; /* used by the macros */
1021 u16 trans_id
, flags
, questions
, answers
, authority
, additional
;
1022 struct server_request
*server_req
= NULL
;
1024 /* Get the header fields */
1032 if (flags
& 0x8000) return -1; /* Must not be an answer. */
1033 flags
&= 0x0110; /* Only RD and CD get preserved. */
1035 if (length
> INT_MAX
)
1038 server_req
= mm_malloc(sizeof(struct server_request
));
1039 if (server_req
== NULL
) return -1;
1040 memset(server_req
, 0, sizeof(struct server_request
));
1042 server_req
->trans_id
= trans_id
;
1043 memcpy(&server_req
->addr
, addr
, addrlen
);
1044 server_req
->addrlen
= addrlen
;
1046 server_req
->base
.flags
= flags
;
1047 server_req
->base
.nquestions
= 0;
1048 server_req
->base
.questions
= mm_malloc(sizeof(struct evdns_server_question
*) * questions
);
1049 if (server_req
->base
.questions
== NULL
)
1052 for (i
= 0; i
< questions
; ++i
) {
1054 struct evdns_server_question
*q
;
1056 if (name_parse(packet
, (int)length
, &j
, tmp_name
, sizeof(tmp_name
))<0)
1060 namelen
= strlen(tmp_name
);
1061 q
= mm_malloc(sizeof(struct evdns_server_question
) + namelen
);
1065 q
->dns_question_class
= class;
1066 memcpy(q
->name
, tmp_name
, namelen
+1);
1067 server_req
->base
.questions
[server_req
->base
.nquestions
++] = q
;
1070 /* Ignore answers, authority, and additional. */
1072 server_req
->port
= port
;
1075 /* Only standard queries are supported. */
1076 if (flags
& 0x7800) {
1077 evdns_server_request_respond(&(server_req
->base
), DNS_ERR_NOTIMPL
);
1081 port
->user_callback(&(server_req
->base
), port
->user_data
);
1086 if (server_req
->base
.questions
) {
1087 for (i
= 0; i
< server_req
->base
.nquestions
; ++i
)
1088 mm_free(server_req
->base
.questions
[i
]);
1089 mm_free(server_req
->base
.questions
);
1092 mm_free(server_req
);
1103 default_transaction_id_fn(void)
1106 #ifdef DNS_USE_CPU_CLOCK_FOR_ID
1108 #ifdef CLOCK_MONOTONIC
1109 if (clock_gettime(CLOCK_MONOTONIC
, &ts
) == -1)
1111 if (clock_gettime(CLOCK_REALTIME
, &ts
) == -1)
1113 event_err(1, "clock_gettime");
1114 trans_id
= ts
.tv_nsec
& 0xffff;
1117 #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
1119 gettimeofday(&tv
, NULL
);
1120 trans_id
= tv
.tv_usec
& 0xffff;
1123 #ifdef DNS_USE_OPENSSL_FOR_ID
1124 if (RAND_pseudo_bytes((u8
*) &trans_id
, 2) == -1) {
1125 /* in the case that the RAND call fails we back */
1126 /* down to using gettimeofday. */
1129 gettimeofday(&tv, NULL);
1130 trans_id = tv.tv_usec & 0xffff;
1135 return (unsigned short) trans_id
;
1138 static uint16_t (*trans_id_function
)(void) = default_transaction_id_fn
;
1141 default_random_bytes_fn(char *buf
, size_t n
)
1144 for (i
= 0; i
< n
; i
+= 2) {
1145 u16 tid
= trans_id_function();
1146 buf
[i
] = (tid
>> 8) & 0xff;
1148 buf
[i
+1] = tid
& 0xff;
1152 static void (*rand_bytes_function
)(char *buf
, size_t n
) =
1153 default_random_bytes_fn
;
1156 trans_id_from_random_bytes_fn(void)
1159 rand_bytes_function((char*) &tid
, sizeof(tid
));
1164 evdns_set_transaction_id_fn(uint16_t (*fn
)(void))
1167 trans_id_function
= fn
;
1169 trans_id_function
= default_transaction_id_fn
;
1170 rand_bytes_function
= default_random_bytes_fn
;
1174 evdns_set_random_bytes_fn(void (*fn
)(char *, size_t))
1176 rand_bytes_function
= fn
;
1177 trans_id_function
= trans_id_from_random_bytes_fn
;
1180 /* Try to choose a strong transaction id which isn't already in flight */
1182 transaction_id_pick(void) {
1184 const struct evdns_request
*req
= req_head
, *started_at
;
1185 u16 trans_id
= trans_id_function();
1187 if (trans_id
== 0xffff) continue;
1188 /* now check to see if that id is already inflight */
1189 req
= started_at
= req_head
;
1192 if (req
->trans_id
== trans_id
) break;
1194 } while (req
!= started_at
);
1196 /* we didn't find it, so this is a good id */
1197 if (req
== started_at
) return trans_id
;
1201 /* choose a namesever to use. This function will try to ignore */
1202 /* nameservers which we think are down and load balance across the rest */
1203 /* by updating the server_head global each time. */
1204 static struct nameserver
*
1205 nameserver_pick(void) {
1206 struct nameserver
*started_at
= server_head
, *picked
;
1207 if (!server_head
) return NULL
;
1209 /* if we don't have any good nameservers then there's no */
1210 /* point in trying to find one. */
1211 if (!global_good_nameservers
) {
1212 server_head
= server_head
->next
;
1216 /* remember that nameservers are in a circular list */
1218 if (server_head
->state
) {
1219 /* we think this server is currently good */
1220 picked
= server_head
;
1221 server_head
= server_head
->next
;
1225 server_head
= server_head
->next
;
1226 if (server_head
== started_at
) {
1227 /* all the nameservers seem to be down */
1228 /* so we just return this one and hope for the */
1230 assert(global_good_nameservers
== 0);
1231 picked
= server_head
;
1232 server_head
= server_head
->next
;
1238 /* this is called when a namesever socket is ready for reading */
1240 nameserver_read(struct nameserver
*ns
) {
1241 struct sockaddr_storage ss
;
1242 struct sockaddr
*sa
= (struct sockaddr
*) &ss
;
1243 socklen_t addrlen
= sizeof(ss
);
1248 (int)recvfrom(ns
->socket
, packet
, (socklen_t
)sizeof(packet
), 0,
1251 int err
= last_error(ns
->socket
);
1252 if (error_is_eagain(err
)) return;
1253 nameserver_failed(ns
, tor_socket_strerror(err
));
1256 /* XXX Match port too? */
1257 if (!sockaddr_eq(sa
, (struct sockaddr
*)&ns
->address
, 0)) {
1259 "Address mismatch on received DNS packet. Address was %s",
1264 reply_parse(packet
, r
);
1268 /* Read a packet from a DNS client on a server port s, parse it, and */
1269 /* act accordingly. */
1271 server_port_read(struct evdns_server_port
*s
) {
1273 struct sockaddr_storage addr
;
1278 addrlen
= (socklen_t
)sizeof(struct sockaddr_storage
);
1279 r
= recvfrom(s
->socket
, packet
, sizeof(packet
), 0,
1280 (struct sockaddr
*) &addr
, &addrlen
);
1282 int err
= last_error(s
->socket
);
1283 if (error_is_eagain(err
)) return;
1284 log(EVDNS_LOG_WARN
, "Error %s (%d) while reading request.",
1285 tor_socket_strerror(err
), err
);
1288 request_parse(packet
, r
, s
, (struct sockaddr
*) &addr
, addrlen
);
1292 /* Try to write all pending replies on a given DNS server port. */
1294 server_port_flush(struct evdns_server_port
*port
)
1296 struct server_request
*req
= port
->pending_replies
;
1298 ssize_t r
= sendto(port
->socket
, req
->response
, req
->response_len
, 0,
1299 (struct sockaddr
*) &req
->addr
, (socklen_t
)req
->addrlen
);
1301 int err
= last_error(port
->socket
);
1302 if (error_is_eagain(err
))
1304 log(EVDNS_LOG_WARN
, "Error %s (%d) while writing response to port; dropping", tor_socket_strerror(err
), err
);
1306 if (server_request_free(req
)) {
1307 /* we released the last reference to req->port. */
1310 assert(port
->pending_replies
!= req
);
1311 req
= port
->pending_replies
;
1315 /* We have no more pending requests; stop listening for 'writeable' events. */
1316 (void) event_del(&port
->event
);
1317 CLEAR(&port
->event
);
1318 event_set(&port
->event
, port
->socket
, EV_READ
| EV_PERSIST
,
1319 server_port_ready_callback
, port
);
1320 if (event_add(&port
->event
, NULL
) < 0) {
1321 log(EVDNS_LOG_WARN
, "Error from libevent when adding event for DNS server.");
1326 /* set if we are waiting for the ability to write to this server. */
1327 /* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
1328 /* we stop these events. */
1330 nameserver_write_waiting(struct nameserver
*ns
, char waiting
) {
1331 if (ns
->write_waiting
== waiting
) return;
1333 ns
->write_waiting
= waiting
;
1334 (void) event_del(&ns
->event
);
1336 event_set(&ns
->event
, ns
->socket
, EV_READ
| (waiting
? EV_WRITE
: 0) | EV_PERSIST
,
1337 nameserver_ready_callback
, ns
);
1338 if (event_add(&ns
->event
, NULL
) < 0) {
1339 log(EVDNS_LOG_WARN
, "Error from libevent when adding event for %s",
1340 debug_ntop((struct sockaddr
*)&ns
->address
));
1345 /* a callback function. Called by libevent when the kernel says that */
1346 /* a nameserver socket is ready for writing or reading */
1348 nameserver_ready_callback(int fd
, short events
, void *arg
) {
1349 struct nameserver
*ns
= (struct nameserver
*) arg
;
1352 if (events
& EV_WRITE
) {
1354 if (!evdns_transmit()) {
1355 nameserver_write_waiting(ns
, 0);
1358 if (events
& EV_READ
) {
1359 nameserver_read(ns
);
1363 /* a callback function. Called by libevent when the kernel says that */
1364 /* a server socket is ready for writing or reading. */
1366 server_port_ready_callback(int fd
, short events
, void *arg
) {
1367 struct evdns_server_port
*port
= (struct evdns_server_port
*) arg
;
1370 if (events
& EV_WRITE
) {
1372 server_port_flush(port
);
1374 if (events
& EV_READ
) {
1375 server_port_read(port
);
1379 /* This is an inefficient representation; only use it via the dnslabel_table_*
1380 * functions, so that is can be safely replaced with something smarter later. */
1381 #define MAX_LABELS 128
1382 /* Structures used to implement name compression */
1383 struct dnslabel_entry
{ char *v
; off_t pos
; };
1384 struct dnslabel_table
{
1385 int n_labels
; /* number of current entries */
1386 /* map from name to position in message */
1387 struct dnslabel_entry labels
[MAX_LABELS
];
1390 /* Initialize dnslabel_table. */
1392 dnslabel_table_init(struct dnslabel_table
*table
)
1394 table
->n_labels
= 0;
1397 /* Free all storage held by table, but not the table itself. */
1399 dnslabel_clear(struct dnslabel_table
*table
)
1402 for (i
= 0; i
< table
->n_labels
; ++i
)
1403 mm_free(table
->labels
[i
].v
);
1404 table
->n_labels
= 0;
1407 /* return the position of the label in the current message, or -1 if the label */
1408 /* hasn't been used yet. */
1410 dnslabel_table_get_pos(const struct dnslabel_table
*table
, const char *label
)
1413 for (i
= 0; i
< table
->n_labels
; ++i
) {
1414 if (!strcmp(label
, table
->labels
[i
].v
)) {
1415 off_t pos
= table
->labels
[i
].pos
;
1424 /* remember that we've used the label at position pos */
1426 dnslabel_table_add(struct dnslabel_table
*table
, const char *label
, off_t pos
)
1430 if (table
->n_labels
== MAX_LABELS
)
1432 v
= mm_strdup(label
);
1435 p
= table
->n_labels
++;
1436 table
->labels
[p
].v
= v
;
1437 table
->labels
[p
].pos
= pos
;
1442 /* Converts a string to a length-prefixed set of DNS labels, starting */
1443 /* at buf[j]. name and buf must not overlap. name_len should be the length */
1444 /* of name. table is optional, and is used for compression. */
1446 /* Input: abc.def */
1447 /* Output: <3>abc<3>def<0> */
1449 /* Returns the first index after the encoded name, or negative on error. */
1450 /* -1 label was > 63 bytes */
1451 /* -2 name too long to fit in buffer. */
1454 dnsname_to_labels(u8
*const buf
, size_t buf_len
, off_t j
,
1455 const char *name
, const size_t name_len
,
1456 struct dnslabel_table
*table
) {
1457 const char *end
= name
+ name_len
;
1461 #define APPEND16(x) do { \
1462 if (j + 2 > (off_t)buf_len) \
1465 memcpy(buf + j, &_t, 2); \
1468 #define APPEND32(x) do { \
1469 if (j + 4 > (off_t)buf_len) \
1472 memcpy(buf + j, &_t32, 4); \
1476 if (name_len
> 255) return -2;
1479 const char *const start
= name
;
1480 if (table
&& (ref
= dnslabel_table_get_pos(table
, name
)) >= 0) {
1481 APPEND16(ref
| 0xc000);
1484 name
= strchr(name
, '.');
1486 const size_t label_len
= end
- start
;
1487 if (label_len
> 63) return -1;
1488 if ((size_t)(j
+label_len
+1) > buf_len
) return -2;
1489 if (table
) dnslabel_table_add(table
, start
, j
);
1490 buf
[j
++] = (uint8_t)label_len
;
1492 memcpy(buf
+ j
, start
, label_len
);
1496 /* append length of the label. */
1497 const size_t label_len
= name
- start
;
1498 if (label_len
> 63) return -1;
1499 if ((size_t)(j
+label_len
+1) > buf_len
) return -2;
1500 if (table
) dnslabel_table_add(table
, start
, j
);
1501 buf
[j
++] = (uint8_t)label_len
;
1503 memcpy(buf
+ j
, start
, name
- start
);
1505 /* hop over the '.' */
1510 /* the labels must be terminated by a 0. */
1511 /* It's possible that the name ended in a . */
1512 /* in which case the zero is already there */
1513 if (!j
|| buf
[j
-1]) buf
[j
++] = 0;
1519 /* Finds the length of a dns request for a DNS name of the given */
1520 /* length. The actual request may be smaller than the value returned */
1523 evdns_request_len(const size_t name_len
) {
1524 return 96 + /* length of the DNS standard header */
1526 4; /* space for the resource type */
1529 /* build a dns request packet into buf. buf should be at least as long */
1530 /* as evdns_request_len told you it should be. */
1532 /* Returns the amount of space used. Negative on error. */
1534 evdns_request_data_build(const char *const name
, const size_t name_len
,
1535 const u16 trans_id
, const u16 type
, const u16
class,
1536 u8
*const buf
, size_t buf_len
) {
1537 off_t j
= 0; /* current offset into buf */
1538 u16 _t
; /* used by the macros */
1541 APPEND16(0x0100); /* standard query, recusion needed */
1542 APPEND16(1); /* one question */
1543 APPEND16(0); /* no answers */
1544 APPEND16(0); /* no authority */
1545 APPEND16(0); /* no additional */
1547 j
= dnsname_to_labels(buf
, buf_len
, j
, name
, name_len
, NULL
);
1560 /* exported function */
1561 struct evdns_server_port
*
1562 evdns_add_server_port(int socket
, int is_tcp
, evdns_request_callback_fn_type cb
, void *user_data
)
1564 struct evdns_server_port
*port
;
1565 if (!(port
= mm_malloc(sizeof(struct evdns_server_port
))))
1567 memset(port
, 0, sizeof(struct evdns_server_port
));
1569 assert(!is_tcp
); /* TCP sockets not yet implemented */
1570 port
->socket
= socket
;
1574 port
->user_callback
= cb
;
1575 port
->user_data
= user_data
;
1576 port
->pending_replies
= NULL
;
1578 event_set(&port
->event
, port
->socket
, EV_READ
| EV_PERSIST
,
1579 server_port_ready_callback
, port
);
1580 if (event_add(&port
->event
, NULL
)<0) {
1587 /* exported function */
1589 evdns_close_server_port(struct evdns_server_port
*port
)
1592 if (--port
->refcnt
== 0)
1593 server_port_free(port
);
1596 /* exported function */
1598 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
)
1600 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1601 struct server_reply_item
**itemp
, *item
;
1604 if (req
->response
) /* have we already answered? */
1608 case EVDNS_ANSWER_SECTION
:
1609 itemp
= &req
->answer
;
1610 countp
= &req
->n_answer
;
1612 case EVDNS_AUTHORITY_SECTION
:
1613 itemp
= &req
->authority
;
1614 countp
= &req
->n_authority
;
1616 case EVDNS_ADDITIONAL_SECTION
:
1617 itemp
= &req
->additional
;
1618 countp
= &req
->n_additional
;
1624 itemp
= &((*itemp
)->next
);
1626 item
= mm_malloc(sizeof(struct server_reply_item
));
1631 if (!(item
->name
= mm_strdup(name
))) {
1637 item
->class = class;
1639 item
->is_name
= is_name
!= 0;
1643 if (item
->is_name
) {
1644 if (!(item
->data
= mm_strdup(data
))) {
1645 mm_free(item
->name
);
1650 item
->datalen
= (u16
)-1;
1652 if (!(item
->data
= mm_malloc(datalen
))) {
1653 mm_free(item
->name
);
1658 item
->datalen
= datalen
;
1659 memcpy(item
->data
, data
, datalen
);
1668 /* exported function */
1670 evdns_server_request_add_a_reply(struct evdns_server_request
*req
, const char *name
, int n
, void *addrs
, int ttl
)
1672 return evdns_server_request_add_reply(
1673 req
, EVDNS_ANSWER_SECTION
, name
, TYPE_A
, CLASS_INET
,
1674 ttl
, n
*4, 0, addrs
);
1677 /* exported function */
1679 evdns_server_request_add_aaaa_reply(struct evdns_server_request
*req
, const char *name
, int n
, void *addrs
, int ttl
)
1681 return evdns_server_request_add_reply(
1682 req
, EVDNS_ANSWER_SECTION
, name
, TYPE_AAAA
, CLASS_INET
,
1683 ttl
, n
*16, 0, addrs
);
1686 /* exported function */
1688 evdns_server_request_add_ptr_reply(struct evdns_server_request
*req
, struct in_addr
*in
, const char *inaddr_name
, const char *hostname
, int ttl
)
1692 assert(in
|| inaddr_name
);
1693 assert(!(in
&& inaddr_name
));
1695 a
= ntohl(in
->s_addr
);
1696 snprintf(buf
, sizeof(buf
), "%d.%d.%d.%d.in-addr.arpa",
1697 (int)(u8
)((a
)&0xff),
1698 (int)(u8
)((a
>>8 )&0xff),
1699 (int)(u8
)((a
>>16)&0xff),
1700 (int)(u8
)((a
>>24)&0xff));
1703 return evdns_server_request_add_reply(
1704 req
, EVDNS_ANSWER_SECTION
, inaddr_name
, TYPE_PTR
, CLASS_INET
,
1705 ttl
, -1, 1, hostname
);
1708 /* exported function */
1710 evdns_server_request_add_cname_reply(struct evdns_server_request
*req
, const char *name
, const char *cname
, int ttl
)
1712 return evdns_server_request_add_reply(
1713 req
, EVDNS_ANSWER_SECTION
, name
, TYPE_CNAME
, CLASS_INET
,
1719 evdns_server_request_format_response(struct server_request
*req
, int err
)
1721 unsigned char buf
[1500];
1722 size_t buf_len
= sizeof(buf
);
1728 struct dnslabel_table table
;
1730 if (err
< 0 || err
> 15) return -1;
1732 /* Set response bit and error code; copy OPCODE and RD fields from
1733 * question; copy RA and AA if set by caller. */
1734 flags
= req
->base
.flags
;
1735 flags
|= (0x8000 | err
);
1737 dnslabel_table_init(&table
);
1738 APPEND16(req
->trans_id
);
1740 APPEND16(req
->base
.nquestions
);
1741 APPEND16(req
->n_answer
);
1742 APPEND16(req
->n_authority
);
1743 APPEND16(req
->n_additional
);
1745 /* Add questions. */
1746 for (i
=0; i
< req
->base
.nquestions
; ++i
) {
1747 const char *s
= req
->base
.questions
[i
]->name
;
1748 j
= dnsname_to_labels(buf
, buf_len
, j
, s
, strlen(s
), &table
);
1750 dnslabel_clear(&table
);
1753 APPEND16(req
->base
.questions
[i
]->type
);
1754 APPEND16(req
->base
.questions
[i
]->dns_question_class
);
1757 /* Add answer, authority, and additional sections. */
1758 for (i
=0; i
<3; ++i
) {
1759 struct server_reply_item
*item
;
1763 item
= req
->authority
;
1765 item
= req
->additional
;
1767 r
= dnsname_to_labels(buf
, buf_len
, j
, item
->name
, strlen(item
->name
), &table
);
1772 APPEND16(item
->type
);
1773 APPEND16(item
->class);
1774 APPEND32(item
->ttl
);
1775 if (item
->is_name
) {
1776 off_t len_idx
= j
, name_start
;
1779 r
= dnsname_to_labels(buf
, buf_len
, j
, item
->data
, strlen(item
->data
), &table
);
1783 _t
= htons( (j
-name_start
) );
1784 memcpy(buf
+len_idx
, &_t
, 2);
1786 APPEND16(item
->datalen
);
1787 if (j
+item
->datalen
> (off_t
)buf_len
)
1789 memcpy(buf
+j
, item
->data
, item
->datalen
);
1799 buf
[2] |= 0x02; /* set the truncated bit. */
1802 req
->response_len
= (size_t)j
;
1804 if (!(req
->response
= mm_malloc(req
->response_len
))) {
1805 server_request_free_answers(req
);
1806 dnslabel_clear(&table
);
1809 memcpy(req
->response
, buf
, req
->response_len
);
1810 server_request_free_answers(req
);
1811 dnslabel_clear(&table
);
1815 /* exported function */
1817 evdns_server_request_respond(struct evdns_server_request
*_req
, int err
)
1819 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1820 struct evdns_server_port
*port
= req
->port
;
1822 if (!req
->response
) {
1823 if ((r
= evdns_server_request_format_response(req
, err
))<0)
1827 r
= sendto(port
->socket
, req
->response
, req
->response_len
, 0,
1828 (struct sockaddr
*) &req
->addr
, req
->addrlen
);
1830 int err
= last_error(port
->socket
);
1831 if (! error_is_eagain(err
))
1834 if (port
->pending_replies
) {
1835 req
->prev_pending
= port
->pending_replies
->prev_pending
;
1836 req
->next_pending
= port
->pending_replies
;
1837 req
->prev_pending
->next_pending
=
1838 req
->next_pending
->prev_pending
= req
;
1840 req
->prev_pending
= req
->next_pending
= req
;
1841 port
->pending_replies
= req
;
1844 (void) event_del(&port
->event
);
1845 CLEAR(&port
->event
);
1846 event_set(&port
->event
, port
->socket
, (port
->closing
?0:EV_READ
) | EV_WRITE
| EV_PERSIST
, server_port_ready_callback
, port
);
1848 if (event_add(&port
->event
, NULL
) < 0) {
1849 log(EVDNS_LOG_WARN
, "Error from libevent when adding event for DNS server");
1856 if (server_request_free(req
))
1859 if (port
->pending_replies
)
1860 server_port_flush(port
);
1865 /* Free all storage held by RRs in req. */
1867 server_request_free_answers(struct server_request
*req
)
1869 struct server_reply_item
*victim
, *next
, **list
;
1871 for (i
= 0; i
< 3; ++i
) {
1873 list
= &req
->answer
;
1875 list
= &req
->authority
;
1877 list
= &req
->additional
;
1881 next
= victim
->next
;
1882 mm_free(victim
->name
);
1884 mm_free(victim
->data
);
1892 /* Free all storage held by req, and remove links to it. */
1893 /* return true iff we just wound up freeing the server_port. */
1895 server_request_free(struct server_request
*req
)
1898 if (req
->base
.questions
) {
1899 for (i
= 0; i
< req
->base
.nquestions
; ++i
)
1900 mm_free(req
->base
.questions
[i
]);
1901 mm_free(req
->base
.questions
);
1905 if (req
->port
->pending_replies
== req
) {
1906 if (req
->next_pending
)
1907 req
->port
->pending_replies
= req
->next_pending
;
1909 req
->port
->pending_replies
= NULL
;
1911 rc
= --req
->port
->refcnt
;
1914 if (req
->response
) {
1915 mm_free(req
->response
);
1918 server_request_free_answers(req
);
1920 if (req
->next_pending
&& req
->next_pending
!= req
) {
1921 req
->next_pending
->prev_pending
= req
->prev_pending
;
1922 req
->prev_pending
->next_pending
= req
->next_pending
;
1926 server_port_free(req
->port
);
1936 /* Free all storage held by an evdns_server_port. Only called when the
1937 * reference count is down to 0. */
1939 server_port_free(struct evdns_server_port
*port
)
1942 assert(!port
->refcnt
);
1943 assert(!port
->pending_replies
);
1944 if (port
->socket
> 0) {
1945 CLOSE_SOCKET(port
->socket
);
1948 (void) event_del(&port
->event
);
1949 CLEAR(&port
->event
);
1954 /* exported function */
1956 evdns_server_request_drop(struct evdns_server_request
*_req
)
1958 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1959 server_request_free(req
);
1963 /* exported function */
1965 evdns_server_request_get_requesting_addr(struct evdns_server_request
*_req
, struct sockaddr
*sa
, int addr_len
)
1967 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1968 if (addr_len
< (int)req
->addrlen
)
1970 memcpy(sa
, &(req
->addr
), req
->addrlen
);
1971 return req
->addrlen
;
1977 /* this is a libevent callback function which is called when a request */
1978 /* has timed out. */
1980 evdns_request_timeout_callback(int fd
, short events
, void *arg
) {
1981 struct evdns_request
*const req
= (struct evdns_request
*) arg
;
1985 log(EVDNS_LOG_DEBUG
, "Request %lx timed out", (unsigned long) arg
);
1987 req
->ns
->timedout
++;
1988 if (req
->ns
->timedout
> global_max_nameserver_timeout
) {
1989 req
->ns
->timedout
= 0;
1990 nameserver_failed(req
->ns
, "request timed out.");
1993 if (req
->tx_count
>= global_max_retransmits
) {
1994 /* this request has failed */
1995 reply_callback(req
, 0, DNS_ERR_TIMEOUT
, NULL
);
1996 request_finished(req
, &req_head
);
1999 /* Stop waiting for the timeout. No need to do this in
2000 * request_finished; that one already deletes the timeout event.
2001 * XXXX021 port this change to libevent. */
2002 del_timeout_event(req
);
2003 evdns_request_transmit(req
);
2007 /* try to send a request to a given server. */
2011 /* 1 temporary failure */
2012 /* 2 other failure */
2014 evdns_request_transmit_to(struct evdns_request
*req
, struct nameserver
*server
) {
2015 const ssize_t r
= send(server
->socket
, req
->request
, req
->request_len
, 0);
2017 int err
= last_error(server
->socket
);
2018 if (error_is_eagain(err
)) return 1;
2019 nameserver_failed(req
->ns
, tor_socket_strerror(err
));
2021 } else if (r
!= (ssize_t
)req
->request_len
) {
2022 return 1; /* short write */
2028 /* try to send a request, updating the fields of the request */
2035 evdns_request_transmit(struct evdns_request
*req
) {
2038 /* if we fail to send this packet then this flag marks it */
2039 /* for evdns_transmit */
2040 req
->transmit_me
= 1;
2041 if (req
->trans_id
== 0xffff) abort();
2043 if (req
->ns
->choked
) {
2044 /* don't bother trying to write to a socket */
2045 /* which we have had EAGAIN from */
2049 r
= evdns_request_transmit_to(req
, req
->ns
);
2053 req
->ns
->choked
= 1;
2054 nameserver_write_waiting(req
->ns
, 1);
2057 /* failed to transmit the request entirely. */
2059 /* fall through: we'll set a timeout, which will time out,
2060 * and make us retransmit the request anyway. */
2062 /* transmitted; we need to check for timeout. */
2063 log(EVDNS_LOG_DEBUG
,
2064 "Setting timeout for request %lx", (unsigned long) req
);
2066 if (add_timeout_event(req
, &global_timeout
) < 0) {
2068 "Error from libevent when adding timer for request %lx",
2069 (unsigned long) req
);
2073 req
->transmit_me
= 0;
2079 nameserver_probe_callback(int result
, char type
, int count
, int ttl
, void *addresses
, void *arg
) {
2080 struct sockaddr
*addr
= arg
;
2081 struct nameserver
*server
;
2087 for (server
= server_head
; server
; server
= server
->next
) {
2088 if (sockaddr_eq(addr
, (struct sockaddr
*) &server
->address
, 1)) {
2089 if (result
== DNS_ERR_NONE
|| result
== DNS_ERR_NOTEXIST
) {
2090 /* this is a good reply */
2091 nameserver_up(server
);
2093 nameserver_probe_failed(server
);
2096 if (server
->next
== server_head
)
2104 nameserver_send_probe(struct nameserver
*const ns
) {
2105 struct evdns_request
*req
;
2106 struct sockaddr_storage
*addr
;
2107 /* here we need to send a probe to a given nameserver */
2108 /* in the hope that it is up now. */
2110 /* We identify the nameserver by its address, in case it is removed before
2111 * our probe comes back. */
2112 addr
= mm_malloc(sizeof(struct sockaddr_storage
));
2113 memcpy(addr
, &ns
->address
, sizeof(struct sockaddr_storage
));
2115 log(EVDNS_LOG_DEBUG
, "Sending probe to %s", debug_ntop((struct sockaddr
*)&ns
->address
));
2117 req
= request_new(TYPE_A
, "www.google.com", DNS_QUERY_NO_SEARCH
, nameserver_probe_callback
, addr
);
2122 /* we force this into the inflight queue no matter what */
2123 request_trans_id_set(req
, transaction_id_pick());
2125 request_submit(req
);
2129 /* 0 didn't try to transmit anything */
2130 /* 1 tried to transmit something */
2132 evdns_transmit(void) {
2133 char did_try_to_transmit
= 0;
2136 struct evdns_request
*const started_at
= req_head
, *req
= req_head
;
2137 /* first transmit all the requests which are currently waiting */
2139 if (req
->transmit_me
) {
2140 did_try_to_transmit
= 1;
2141 evdns_request_transmit(req
);
2145 } while (req
!= started_at
);
2148 return did_try_to_transmit
;
2151 /* exported function */
2153 evdns_count_nameservers(void)
2155 const struct nameserver
*server
= server_head
;
2161 server
= server
->next
;
2162 } while (server
!= server_head
);
2166 /* exported function */
2168 evdns_clear_nameservers_and_suspend(void)
2170 struct nameserver
*server
= server_head
, *started_at
= server_head
;
2171 struct evdns_request
*req
= req_head
, *req_started_at
= req_head
;
2176 struct nameserver
*next
= server
->next
;
2177 (void) event_del(&server
->event
);
2178 CLEAR(&server
->event
);
2179 del_timeout_event(server
);
2180 if (server
->socket
>= 0)
2181 CLOSE_SOCKET(server
->socket
);
2184 if (next
== started_at
)
2189 global_good_nameservers
= 0;
2192 struct evdns_request
*next
= req
->next
;
2193 req
->tx_count
= req
->reissue_count
= 0;
2195 /* ???? What to do about searches? */
2196 del_timeout_event(req
);
2198 req
->transmit_me
= 0;
2200 global_requests_waiting
++;
2201 evdns_request_insert(req
, &req_waiting_head
);
2202 /* We want to insert these suspended elements at the front of
2203 * the waiting queue, since they were pending before any of
2204 * the waiting entries were added. This is a circular list,
2205 * so we can just shift the start back by one.*/
2206 req_waiting_head
= req_waiting_head
->prev
;
2208 if (next
== req_started_at
)
2213 global_requests_inflight
= 0;
2218 static struct sockaddr_storage global_bind_address
;
2219 static socklen_t global_bind_addrlen
= 0;
2220 static int global_bind_addr_is_set
= 0;
2222 evdns_set_default_outgoing_bind_address(const struct sockaddr
*addr
,
2225 memset(&global_bind_address
, 0, sizeof(global_bind_address
));
2227 assert(addrlen
<= (socklen_t
)sizeof(global_bind_address
));
2228 memcpy(&global_bind_address
, addr
, addrlen
);
2229 global_bind_addrlen
= addrlen
;
2230 global_bind_addr_is_set
= 1;
2232 global_bind_addr_is_set
= 0;
2236 /* exported function */
2240 evdns_requests_pump_waiting_queue();
2245 sockaddr_is_loopback(const struct sockaddr
*addr
)
2247 static const char LOOPBACK_S6
[16] =
2248 "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1";
2249 if (addr
->sa_family
== AF_INET
) {
2250 struct sockaddr_in
*sin
= (struct sockaddr_in
*)addr
;
2251 return (ntohl(sin
->sin_addr
.s_addr
) & 0xff000000) == 0x7f000000;
2252 } else if (addr
->sa_family
== AF_INET6
) {
2253 struct sockaddr_in6
*sin6
= (struct sockaddr_in6
*)addr
;
2254 return !memcmp(sin6
->sin6_addr
.s6_addr
, LOOPBACK_S6
, 16);
2260 _evdns_nameserver_add_impl(const struct sockaddr
*address
,
2261 socklen_t addrlen
) {
2262 /* first check to see if we already have this nameserver */
2264 const struct nameserver
*server
= server_head
, *const started_at
= server_head
;
2265 struct nameserver
*ns
;
2270 if (sockaddr_eq(address
, (struct sockaddr
*)&server
->address
, 1)) {
2271 log(EVDNS_LOG_DEBUG
, "Duplicate nameserver.");
2274 server
= server
->next
;
2275 } while (server
!= started_at
);
2277 if (addrlen
> (int)sizeof(ns
->address
)) {
2278 log(EVDNS_LOG_DEBUG
, "Addrlen %d too long.", (int)addrlen
);
2282 ns
= (struct nameserver
*) mm_malloc(sizeof(struct nameserver
));
2285 memset(ns
, 0, sizeof(struct nameserver
));
2287 evtimer_set(&ns
->timeout_event
, nameserver_prod_callback
, ns
);
2289 ns
->socket
= socket(PF_INET
, SOCK_DGRAM
, 0);
2290 if (ns
->socket
< 0) { err
= 1; goto out1
; }
2293 u_long nonblocking
= 1;
2294 ioctlsocket(ns
->socket
, FIONBIO
, &nonblocking
);
2297 fcntl(ns
->socket
, F_SETFL
, O_NONBLOCK
);
2300 if (global_bind_addr_is_set
&&
2301 !sockaddr_is_loopback((struct sockaddr
*)&global_bind_address
)) {
2302 if (bind(ns
->socket
, (struct sockaddr
*)&global_bind_address
,
2303 global_bind_addrlen
) < 0) {
2304 log(EVDNS_LOG_DEBUG
, "Couldn't bind to outgoing address.");
2310 if (connect(ns
->socket
, address
, addrlen
) != 0) {
2311 log(EVDNS_LOG_DEBUG
, "Couldn't open socket to nameserver.");
2316 memcpy(&ns
->address
, address
, addrlen
);
2318 event_set(&ns
->event
, ns
->socket
, EV_READ
| EV_PERSIST
, nameserver_ready_callback
, ns
);
2319 if (event_add(&ns
->event
, NULL
) < 0) {
2320 log(EVDNS_LOG_DEBUG
, "Couldn't add event for nameserver.");
2325 log(EVDNS_LOG_DEBUG
, "Added nameserver %s", debug_ntop(address
));
2327 /* insert this nameserver into the list of them */
2329 ns
->next
= ns
->prev
= ns
;
2332 ns
->next
= server_head
->next
;
2333 ns
->prev
= server_head
;
2334 server_head
->next
= ns
;
2335 if (server_head
->prev
== server_head
) {
2336 server_head
->prev
= ns
;
2340 global_good_nameservers
++;
2345 CLOSE_SOCKET(ns
->socket
);
2349 log(EVDNS_LOG_WARN
, "Unable to add nameserver %s: error %d", debug_ntop(address
), err
);
2353 /* exported function */
2355 evdns_nameserver_add(uint32_t address
) {
2356 struct sockaddr_in sin
;
2357 memset(&sin
, 0, sizeof(sin
));
2358 sin
.sin_family
= AF_INET
;
2359 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
2360 sin
.sin_len
= sizeof(sin
);
2362 sin
.sin_addr
.s_addr
= htonl(address
);
2364 return _evdns_nameserver_add_impl((struct sockaddr
*) &sin
, sizeof(sin
));
2367 /* exported function */
2369 evdns_nameserver_ip_add(const char *ip_as_string
) {
2372 const char *cp
, *addr_part
, *port_part
;
2374 /* recognized formats are:
2382 log(EVDNS_LOG_DEBUG
, "Trying to add nameserver <%s>", ip_as_string
);
2384 cp
= strchr(ip_as_string
, ':');
2385 if (*ip_as_string
== '[') {
2387 if (!(cp
= strchr(ip_as_string
, ']'))) {
2388 log(EVDNS_LOG_DEBUG
, "Nameserver missing closing ]");
2391 len
= cp
-(ip_as_string
+ 1);
2392 if (len
> sizeof(buf
)-1) {
2393 log(EVDNS_LOG_DEBUG
, "[Nameserver] does not fit in buffer.");
2396 memcpy(buf
, ip_as_string
+1, len
);
2404 } else if (cp
&& strchr(cp
+1, ':')) {
2406 addr_part
= ip_as_string
;
2410 if (cp
- ip_as_string
> (int)sizeof(buf
)-1) {
2411 log(EVDNS_LOG_DEBUG
, "Nameserver does not fit in buffer.");
2414 memcpy(buf
, ip_as_string
, cp
-ip_as_string
);
2415 buf
[cp
-ip_as_string
] = '\0';
2419 addr_part
= ip_as_string
;
2424 if (port_part
== NULL
) {
2427 port
= strtoint(port_part
);
2428 if (port
<= 0 || port
> 65535) {
2429 log(EVDNS_LOG_DEBUG
, "Nameserver port <%s> out of range",
2435 /* Tor-only. needs a more general fix. */
2438 struct sockaddr_in6 sin6
;
2439 memset(&sin6
, 0, sizeof(sin6
));
2440 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN
2441 sin6
.sin6_len
= sizeof(sin6
);
2443 sin6
.sin6_family
= AF_INET6
;
2444 sin6
.sin6_port
= htons(port
);
2445 if (1 != tor_inet_pton(AF_INET6
, addr_part
, &sin6
.sin6_addr
)) {
2446 log(EVDNS_LOG_DEBUG
, "inet_pton(%s) failed", addr_part
);
2449 return _evdns_nameserver_add_impl((struct sockaddr
*)&sin6
,
2452 struct sockaddr_in sin
;
2453 memset(&sin
, 0, sizeof(sin
));
2454 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
2455 sin
.sin_len
= sizeof(sin
);
2457 sin
.sin_family
= AF_INET
;
2458 sin
.sin_port
= htons(port
);
2459 if (!inet_aton(addr_part
, &sin
.sin_addr
)) {
2460 log(EVDNS_LOG_DEBUG
, "inet_pton(%s) failed", addr_part
);
2463 return _evdns_nameserver_add_impl((struct sockaddr
*)&sin
,
2469 evdns_nameserver_sockaddr_add(const struct sockaddr
*sa
, socklen_t len
)
2471 return _evdns_nameserver_add_impl(sa
, len
);
2474 /* insert into the tail of the queue */
2476 evdns_request_insert(struct evdns_request
*req
, struct evdns_request
**head
) {
2479 req
->next
= req
->prev
= req
;
2483 req
->prev
= (*head
)->prev
;
2484 req
->prev
->next
= req
;
2486 (*head
)->prev
= req
;
2490 string_num_dots(const char *s
) {
2492 while ((s
= strchr(s
, '.'))) {
2499 static struct evdns_request
*
2500 request_new(int type
, const char *name
, int flags
,
2501 evdns_callback_type callback
, void *user_ptr
) {
2502 const char issuing_now
=
2503 (global_requests_inflight
< global_max_requests_inflight
) ? 1 : 0;
2505 const size_t name_len
= strlen(name
);
2506 const size_t request_max_len
= evdns_request_len(name_len
);
2507 const u16 trans_id
= issuing_now
? transaction_id_pick() : 0xffff;
2508 /* the request data is alloced in a single block with the header */
2509 struct evdns_request
*const req
=
2510 (struct evdns_request
*) mm_malloc(sizeof(struct evdns_request
) + request_max_len
);
2515 if (!req
) return NULL
;
2517 if (name_len
>= sizeof(namebuf
)) {
2522 memset(req
, 0, sizeof(struct evdns_request
));
2524 evtimer_set(&req
->timeout_event
, evdns_request_timeout_callback
, req
);
2526 if (global_randomize_case
) {
2529 strlcpy(namebuf
, name
, sizeof(namebuf
));
2530 rand_bytes_function(randbits
, (name_len
+7)/8);
2531 for (i
= 0; i
< name_len
; ++i
) {
2532 if (ISALPHA(namebuf
[i
])) {
2533 if ((randbits
[i
>> 3] & (1<<(i
%7))))
2534 namebuf
[i
] = TOLOWER(namebuf
[i
]);
2536 namebuf
[i
] = TOUPPER(namebuf
[i
]);
2542 /* request data lives just after the header */
2543 req
->request
= ((u8
*) req
) + sizeof(struct evdns_request
);
2544 /* denotes that the request data shouldn't be mm_free()ed */
2545 req
->request_appended
= 1;
2546 rlen
= evdns_request_data_build(name
, name_len
, trans_id
,
2547 type
, CLASS_INET
, req
->request
, request_max_len
);
2550 req
->request_len
= rlen
;
2551 req
->trans_id
= trans_id
;
2553 req
->request_type
= type
;
2554 req
->user_pointer
= user_ptr
;
2555 req
->user_callback
= callback
;
2556 req
->ns
= issuing_now
? nameserver_pick() : NULL
;
2557 req
->next
= req
->prev
= NULL
;
2567 request_submit(struct evdns_request
*const req
) {
2569 /* if it has a nameserver assigned then this is going */
2570 /* straight into the inflight queue */
2571 evdns_request_insert(req
, &req_head
);
2572 global_requests_inflight
++;
2573 evdns_request_transmit(req
);
2575 evdns_request_insert(req
, &req_waiting_head
);
2576 global_requests_waiting
++;
2580 /* exported function */
2581 int evdns_resolve_ipv4(const char *name
, int flags
,
2582 evdns_callback_type callback
, void *ptr
) {
2583 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s", name
);
2584 if (flags
& DNS_QUERY_NO_SEARCH
) {
2585 struct evdns_request
*const req
=
2586 request_new(TYPE_A
, name
, flags
, callback
, ptr
);
2589 request_submit(req
);
2592 return (search_request_new(TYPE_A
, name
, flags
, callback
, ptr
));
2596 /* exported function */
2597 int evdns_resolve_ipv6(const char *name
, int flags
,
2598 evdns_callback_type callback
, void *ptr
) {
2599 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s", name
);
2600 if (flags
& DNS_QUERY_NO_SEARCH
) {
2601 struct evdns_request
*const req
=
2602 request_new(TYPE_AAAA
, name
, flags
, callback
, ptr
);
2605 request_submit(req
);
2608 return (search_request_new(TYPE_AAAA
, name
, flags
, callback
, ptr
));
2612 int evdns_resolve_reverse(const struct in_addr
*in
, int flags
, evdns_callback_type callback
, void *ptr
) {
2614 struct evdns_request
*req
;
2617 a
= ntohl(in
->s_addr
);
2618 snprintf(buf
, sizeof(buf
), "%d.%d.%d.%d.in-addr.arpa",
2619 (int)(u8
)((a
)&0xff),
2620 (int)(u8
)((a
>>8 )&0xff),
2621 (int)(u8
)((a
>>16)&0xff),
2622 (int)(u8
)((a
>>24)&0xff));
2623 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s (reverse)", buf
);
2624 req
= request_new(TYPE_PTR
, buf
, flags
, callback
, ptr
);
2626 request_submit(req
);
2630 int evdns_resolve_reverse_ipv6(const struct in6_addr
*in
, int flags
, evdns_callback_type callback
, void *ptr
) {
2631 /* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
2634 struct evdns_request
*req
;
2638 for (i
=15; i
>= 0; --i
) {
2639 u8 byte
= in
->s6_addr
[i
];
2640 *cp
++ = "0123456789abcdef"[byte
& 0x0f];
2642 *cp
++ = "0123456789abcdef"[byte
>> 4];
2645 assert(cp
+ strlen("ip6.arpa") < buf
+sizeof(buf
));
2646 memcpy(cp
, "ip6.arpa", strlen("ip6.arpa")+1);
2647 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s (reverse)", buf
);
2648 req
= request_new(TYPE_PTR
, buf
, flags
, callback
, ptr
);
2650 request_submit(req
);
2654 /*/////////////////////////////////////////////////////////////////// */
2655 /* Search support */
2657 /* the libc resolver has support for searching a number of domains */
2658 /* to find a name. If nothing else then it takes the single domain */
2659 /* from the gethostname() call. */
2661 /* It can also be configured via the domain and search options in a */
2664 /* The ndots option controls how many dots it takes for the resolver */
2665 /* to decide that a name is non-local and so try a raw lookup first. */
2667 struct search_domain
{
2669 struct search_domain
*next
;
2670 /* the text string is appended to this structure */
2673 struct search_state
{
2677 struct search_domain
*head
;
2680 static struct search_state
*global_search_state
= NULL
;
2683 search_state_decref(struct search_state
*const state
) {
2686 if (!state
->refcount
) {
2687 struct search_domain
*next
, *dom
;
2688 for (dom
= state
->head
; dom
; dom
= next
) {
2698 static struct search_state
*
2699 search_state_new(void) {
2700 struct search_state
*state
= (struct search_state
*) mm_malloc(sizeof(struct search_state
));
2701 if (!state
) return NULL
;
2702 memset(state
, 0, sizeof(struct search_state
));
2703 state
->refcount
= 1;
2710 search_postfix_clear(void) {
2711 search_state_decref(global_search_state
);
2713 global_search_state
= search_state_new();
2716 /* exported function */
2718 evdns_search_clear(void) {
2719 search_postfix_clear();
2723 search_postfix_add(const char *domain
) {
2725 struct search_domain
*sdomain
;
2726 while (domain
[0] == '.') domain
++;
2727 domain_len
= strlen(domain
);
2729 if (!global_search_state
) global_search_state
= search_state_new();
2730 if (!global_search_state
) return;
2731 global_search_state
->num_domains
++;
2733 sdomain
= (struct search_domain
*) mm_malloc(sizeof(struct search_domain
) + domain_len
);
2734 if (!sdomain
) return;
2735 memcpy( ((u8
*) sdomain
) + sizeof(struct search_domain
), domain
, domain_len
);
2736 sdomain
->next
= global_search_state
->head
;
2737 sdomain
->len
= domain_len
;
2739 global_search_state
->head
= sdomain
;
2742 /* reverse the order of members in the postfix list. This is needed because, */
2743 /* when parsing resolv.conf we push elements in the wrong order */
2745 search_reverse(void) {
2746 struct search_domain
*cur
, *prev
= NULL
, *next
;
2747 cur
= global_search_state
->head
;
2755 global_search_state
->head
= prev
;
2758 /* exported function */
2760 evdns_search_add(const char *domain
) {
2761 search_postfix_add(domain
);
2764 /* exported function */
2766 evdns_search_ndots_set(const int ndots
) {
2767 if (!global_search_state
) global_search_state
= search_state_new();
2768 if (!global_search_state
) return;
2769 global_search_state
->ndots
= ndots
;
2773 search_set_from_hostname(void) {
2774 char hostname
[HOST_NAME_MAX
+ 1], *domainname
;
2776 search_postfix_clear();
2777 if (gethostname(hostname
, sizeof(hostname
))) return;
2778 domainname
= strchr(hostname
, '.');
2779 if (!domainname
) return;
2780 search_postfix_add(domainname
);
2783 /* warning: returns malloced string */
2785 search_make_new(const struct search_state
*const state
, int n
, const char *const base_name
) {
2786 const size_t base_len
= strlen(base_name
);
2787 const char need_to_append_dot
= base_name
[base_len
- 1] == '.' ? 0 : 1;
2788 struct search_domain
*dom
;
2790 for (dom
= state
->head
; dom
; dom
= dom
->next
) {
2792 /* this is the postfix we want */
2793 /* the actual postfix string is kept at the end of the structure */
2794 const u8
*const postfix
= ((u8
*) dom
) + sizeof(struct search_domain
);
2795 const size_t postfix_len
= dom
->len
;
2796 char *const newname
= (char *) mm_malloc(base_len
+ need_to_append_dot
+ postfix_len
+ 1);
2797 if (!newname
) return NULL
;
2798 memcpy(newname
, base_name
, base_len
);
2799 if (need_to_append_dot
) newname
[base_len
] = '.';
2800 memcpy(newname
+ base_len
+ need_to_append_dot
, postfix
, postfix_len
);
2801 newname
[base_len
+ need_to_append_dot
+ postfix_len
] = 0;
2806 /* we ran off the end of the list and still didn't find the requested string */
2808 return NULL
; /* unreachable; stops warnings in some compilers. */
2812 search_request_new(int type
, const char *const name
, int flags
, evdns_callback_type user_callback
, void *user_arg
) {
2813 assert(type
== TYPE_A
|| type
== TYPE_AAAA
);
2814 if ( ((flags
& DNS_QUERY_NO_SEARCH
) == 0) &&
2815 global_search_state
&&
2816 global_search_state
->num_domains
) {
2817 /* we have some domains to search */
2818 struct evdns_request
*req
;
2819 if (string_num_dots(name
) >= global_search_state
->ndots
) {
2820 req
= request_new(type
, name
, flags
, user_callback
, user_arg
);
2822 req
->search_index
= -1;
2824 char *const new_name
= search_make_new(global_search_state
, 0, name
);
2825 if (!new_name
) return 1;
2826 req
= request_new(type
, new_name
, flags
, user_callback
, user_arg
);
2829 req
->search_index
= 0;
2831 req
->search_origname
= mm_strdup(name
);
2832 req
->search_state
= global_search_state
;
2833 req
->search_flags
= flags
;
2834 global_search_state
->refcount
++;
2835 request_submit(req
);
2838 struct evdns_request
*const req
= request_new(type
, name
, flags
, user_callback
, user_arg
);
2840 request_submit(req
);
2845 /* this is called when a request has failed to find a name. We need to check */
2846 /* if it is part of a search and, if so, try the next name in the list */
2848 /* 0 another request has been submitted */
2849 /* 1 no more requests needed */
2851 search_try_next(struct evdns_request
*const req
) {
2852 if (req
->search_state
) {
2853 /* it is part of a search */
2855 struct evdns_request
*newreq
;
2856 req
->search_index
++;
2857 if (req
->search_index
>= req
->search_state
->num_domains
) {
2858 /* no more postfixes to try, however we may need to try */
2859 /* this name without a postfix */
2860 if (string_num_dots(req
->search_origname
) < req
->search_state
->ndots
) {
2861 /* yep, we need to try it raw */
2862 struct evdns_request
*const newreq
= request_new(req
->request_type
, req
->search_origname
, req
->search_flags
, req
->user_callback
, req
->user_pointer
);
2863 log(EVDNS_LOG_DEBUG
, "Search: trying raw query %s", req
->search_origname
);
2865 request_submit(newreq
);
2872 new_name
= search_make_new(req
->search_state
, req
->search_index
, req
->search_origname
);
2873 if (!new_name
) return 1;
2874 log(EVDNS_LOG_DEBUG
, "Search: now trying %s (%d)", new_name
, req
->search_index
);
2875 newreq
= request_new(req
->request_type
, new_name
, req
->search_flags
, req
->user_callback
, req
->user_pointer
);
2877 if (!newreq
) return 1;
2878 newreq
->search_origname
= req
->search_origname
;
2879 req
->search_origname
= NULL
;
2880 newreq
->search_state
= req
->search_state
;
2881 newreq
->search_flags
= req
->search_flags
;
2882 newreq
->search_index
= req
->search_index
;
2883 newreq
->search_state
->refcount
++;
2884 request_submit(newreq
);
2891 search_request_finished(struct evdns_request
*const req
) {
2892 if (req
->search_state
) {
2893 search_state_decref(req
->search_state
);
2894 req
->search_state
= NULL
;
2896 if (req
->search_origname
) {
2897 mm_free(req
->search_origname
);
2898 req
->search_origname
= NULL
;
2902 /*/////////////////////////////////////////////////////////////////// */
2903 /* Parsing resolv.conf files */
2906 evdns_resolv_set_defaults(int flags
) {
2907 /* if the file isn't found then we assume a local resolver */
2908 if (flags
& DNS_OPTION_SEARCH
) search_set_from_hostname();
2909 if (flags
& DNS_OPTION_NAMESERVERS
) evdns_nameserver_ip_add("127.0.0.1");
2912 /* helper version of atoi which returns -1 on error */
2914 strtoint(const char *const str
) {
2916 const long r
= strtol(str
, &endptr
, 10);
2917 if (*endptr
|| r
> INT_MAX
) return -1;
2921 /* helper version of atoi that returns -1 on error and clips to bounds. */
2923 strtoint_clipped(const char *const str
, int min
, int max
)
2925 int r
= strtoint(str
);
2936 /* exported function */
2938 evdns_set_option(const char *option
, const char *val
, int flags
)
2940 if (!strncmp(option
, "ndots:", 6)) {
2941 const int ndots
= strtoint(val
);
2942 if (ndots
== -1) return -1;
2943 if (!(flags
& DNS_OPTION_SEARCH
)) return 0;
2944 log(EVDNS_LOG_DEBUG
, "Setting ndots to %d", ndots
);
2945 if (!global_search_state
) global_search_state
= search_state_new();
2946 if (!global_search_state
) return -1;
2947 global_search_state
->ndots
= ndots
;
2948 } else if (!strncmp(option
, "timeout:", 8)) {
2949 const int timeout
= strtoint(val
);
2950 if (timeout
== -1) return -1;
2951 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2952 log(EVDNS_LOG_DEBUG
, "Setting timeout to %d", timeout
);
2953 global_timeout
.tv_sec
= timeout
;
2954 } else if (!strncmp(option
, "max-timeouts:", 12)) {
2955 const int maxtimeout
= strtoint_clipped(val
, 1, 255);
2956 if (maxtimeout
== -1) return -1;
2957 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2958 log(EVDNS_LOG_DEBUG
, "Setting maximum allowed timeouts to %d",
2960 global_max_nameserver_timeout
= maxtimeout
;
2961 } else if (!strncmp(option
, "max-inflight:", 13)) {
2962 const int maxinflight
= strtoint_clipped(val
, 1, 65000);
2963 if (maxinflight
== -1) return -1;
2964 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2965 log(EVDNS_LOG_DEBUG
, "Setting maximum inflight requests to %d",
2967 global_max_requests_inflight
= maxinflight
;
2968 } else if (!strncmp(option
, "attempts:", 9)) {
2969 int retries
= strtoint(val
);
2970 if (retries
== -1) return -1;
2971 if (retries
> 255) retries
= 255;
2972 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2973 log(EVDNS_LOG_DEBUG
, "Setting retries to %d", retries
);
2974 global_max_retransmits
= retries
;
2975 } else if (!strncmp(option
, "randomize-case:", 15)) {
2976 int randcase
= strtoint(val
);
2977 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2978 log(EVDNS_LOG_DEBUG
, "Setting randomize_case to %d", randcase
);
2979 global_randomize_case
= randcase
;
2985 resolv_conf_parse_line(char *const start
, int flags
) {
2987 static const char *const delims
= " \t";
2988 #define NEXT_TOKEN tor_strtok_r(NULL, delims, &strtok_state)
2990 char *const first_token
= tor_strtok_r(start
, delims
, &strtok_state
);
2991 if (!first_token
) return;
2993 if (!strcmp(first_token
, "nameserver") && (flags
& DNS_OPTION_NAMESERVERS
)) {
2994 const char *const nameserver
= NEXT_TOKEN
;
2995 evdns_nameserver_ip_add(nameserver
);
2996 } else if (!strcmp(first_token
, "domain") && (flags
& DNS_OPTION_SEARCH
)) {
2997 const char *const domain
= NEXT_TOKEN
;
2999 search_postfix_clear();
3000 search_postfix_add(domain
);
3002 } else if (!strcmp(first_token
, "search") && (flags
& DNS_OPTION_SEARCH
)) {
3004 search_postfix_clear();
3006 while ((domain
= NEXT_TOKEN
)) {
3007 search_postfix_add(domain
);
3010 } else if (!strcmp(first_token
, "options")) {
3012 while ((option
= NEXT_TOKEN
)) {
3013 const char *val
= strchr(option
, ':');
3014 evdns_set_option(option
, val
? val
+1 : "", flags
);
3020 /* exported function */
3023 /* 1 failed to open file */
3024 /* 2 failed to stat file */
3025 /* 3 file too large */
3026 /* 4 out of memory */
3027 /* 5 short read from file */
3029 evdns_resolv_conf_parse(int flags
, const char *const filename
) {
3036 log(EVDNS_LOG_DEBUG
, "Parsing resolv.conf file %s", filename
);
3038 fd
= open(filename
, O_RDONLY
);
3040 evdns_resolv_set_defaults(flags
);
3044 if (fstat(fd
, &st
)) { err
= 2; goto out1
; }
3046 evdns_resolv_set_defaults(flags
);
3047 err
= (flags
& DNS_OPTION_NAMESERVERS
) ? 6 : 0;
3050 if (st
.st_size
> 65535) { err
= 3; goto out1
; } /* no resolv.conf should be any bigger */
3052 resolv
= (u8
*) mm_malloc((size_t)st
.st_size
+ 1);
3053 if (!resolv
) { err
= 4; goto out1
; }
3056 while ((r
= (int)read(fd
, resolv
+n
, (size_t)st
.st_size
-n
)) > 0) {
3058 if (n
== st
.st_size
)
3060 assert(n
< st
.st_size
);
3062 if (r
< 0) { err
= 5; goto out2
; }
3063 resolv
[n
] = 0; /* we malloced an extra byte; this should be fine. */
3065 start
= (char *) resolv
;
3067 char *const newline
= strchr(start
, '\n');
3069 resolv_conf_parse_line(start
, flags
);
3073 resolv_conf_parse_line(start
, flags
);
3074 start
= newline
+ 1;
3078 if (!server_head
&& (flags
& DNS_OPTION_NAMESERVERS
)) {
3079 /* no nameservers were configured. */
3080 evdns_nameserver_ip_add("127.0.0.1");
3083 if (flags
& DNS_OPTION_SEARCH
&& (!global_search_state
|| global_search_state
->num_domains
== 0)) {
3084 search_set_from_hostname();
3095 /* Add multiple nameservers from a space-or-comma-separated list. */
3097 evdns_nameserver_ip_add_line(const char *ips
) {
3102 while (ISSPACE(*ips
) || *ips
== ',' || *ips
== '\t')
3105 while (ISDIGIT(*ips
) || *ips
== '.' || *ips
== ':' || *ips
== '[' || *ips
== ']')
3107 buf
= mm_malloc(ips
-addr
+1);
3109 memcpy(buf
, addr
, ips
-addr
);
3110 buf
[ips
-addr
] = '\0';
3111 r
= evdns_nameserver_ip_add(buf
);
3118 typedef DWORD(WINAPI
*GetNetworkParams_fn_t
)(FIXED_INFO
*, DWORD
*);
3120 /* Use the windows GetNetworkParams interface in iphlpapi.dll to */
3121 /* figure out what our nameservers are. */
3123 load_nameservers_with_getnetworkparams(void)
3125 /* Based on MSDN examples and inspection of c-ares code. */
3128 ULONG size
= sizeof(FIXED_INFO
);
3130 int status
= 0, r
, added_any
;
3132 GetNetworkParams_fn_t fn
;
3134 /* XXXX Possibly, we should hardcode the location of this DLL. */
3135 if (!(handle
= LoadLibrary(TEXT("iphlpapi.dll")))) {
3136 log(EVDNS_LOG_WARN
, "Could not open iphlpapi.dll");
3137 /* right now status = 0, doesn't that mean "good" - mikec */
3141 if (!(fn
= (GetNetworkParams_fn_t
) GetProcAddress(handle
, TEXT("GetNetworkParams")))) {
3142 log(EVDNS_LOG_WARN
, "Could not get address of function.");
3148 buf
= mm_malloc(size
);
3149 if (!buf
) { status
= 4; goto done
; }
3151 r
= fn(fixed
, &size
);
3152 if (r
!= ERROR_SUCCESS
&& r
!= ERROR_BUFFER_OVERFLOW
) {
3156 if (r
!= ERROR_SUCCESS
) {
3158 buf
= mm_malloc(size
);
3159 if (!buf
) { status
= 4; goto done
; }
3161 r
= fn(fixed
, &size
);
3162 if (r
!= ERROR_SUCCESS
) {
3163 log(EVDNS_LOG_DEBUG
, "fn() failed.");
3171 ns
= &(fixed
->DnsServerList
);
3173 r
= evdns_nameserver_ip_add_line(ns
->IpAddress
.String
);
3175 log(EVDNS_LOG_DEBUG
,"Could not add nameserver %s to list, "
3176 "error: %d; status: %d",
3177 (ns
->IpAddress
.String
),(int)GetLastError(), r
);
3180 log(EVDNS_LOG_DEBUG
,"Successfully added %s as nameserver",ns
->IpAddress
.String
);
3188 log(EVDNS_LOG_DEBUG
, "No nameservers added.");
3199 FreeLibrary(handle
);
3204 config_nameserver_from_reg_key(HKEY key
, const TCHAR
*subkey
)
3207 char ansibuf
[MAX_PATH
] = {0};
3208 DWORD bufsz
= 0, type
= 0;
3211 if (RegQueryValueEx(key
, subkey
, 0, &type
, NULL
, &bufsz
)
3214 if (!(buf
= mm_malloc(bufsz
)))
3217 if (RegQueryValueEx(key
, subkey
, 0, &type
, (LPBYTE
)buf
, &bufsz
)
3218 == ERROR_SUCCESS
&& bufsz
> 1) {
3219 wcstombs(ansibuf
,(wchar_t*)buf
,MAX_PATH
);/*XXXX UNICODE */
3220 status
= evdns_nameserver_ip_add_line(ansibuf
);
3227 #define SERVICES_KEY TEXT("System\\CurrentControlSet\\Services\\")
3228 #define WIN_NS_9X_KEY SERVICES_KEY TEXT("VxD\\MSTCP")
3229 #define WIN_NS_NT_KEY SERVICES_KEY TEXT("Tcpip\\Parameters")
3232 load_nameservers_from_registry(void)
3237 memset(&info
, 0, sizeof(info
));
3238 info
.dwOSVersionInfoSize
= sizeof (info
);
3239 GetVersionEx(&info
);
3241 #define TRY(k, name) \
3242 if (!found && config_nameserver_from_reg_key(k,TEXT(name)) == 0) { \
3243 log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \
3245 } else if (!found) { \
3246 log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \
3250 if (info
.dwMajorVersion
>= 5) { /* NT */
3251 HKEY nt_key
= 0, interfaces_key
= 0;
3253 if (RegOpenKeyEx(HKEY_LOCAL_MACHINE
, WIN_NS_NT_KEY
, 0,
3254 KEY_READ
, &nt_key
) != ERROR_SUCCESS
) {
3255 log(EVDNS_LOG_DEBUG
,"Couldn't open nt key, %d",(int)GetLastError());
3258 r
= RegOpenKeyEx(nt_key
, TEXT("Interfaces"), 0,
3259 KEY_QUERY_VALUE
|KEY_ENUMERATE_SUB_KEYS
,
3261 if (r
!= ERROR_SUCCESS
) {
3262 log(EVDNS_LOG_DEBUG
,"Couldn't open interfaces key, %d",(int)GetLastError());
3265 TRY(nt_key
, "NameServer");
3266 TRY(nt_key
, "DhcpNameServer");
3267 TRY(interfaces_key
, "NameServer");
3268 TRY(interfaces_key
, "DhcpNameServer");
3269 RegCloseKey(interfaces_key
);
3270 RegCloseKey(nt_key
);
3273 if (RegOpenKeyEx(HKEY_LOCAL_MACHINE
, WIN_NS_9X_KEY
, 0,
3274 KEY_READ
, &win_key
) != ERROR_SUCCESS
) {
3275 log(EVDNS_LOG_DEBUG
, "Couldn't open registry key, %d", (int)GetLastError());
3278 TRY(win_key
, "NameServer");
3279 RegCloseKey(win_key
);
3283 log(EVDNS_LOG_WARN
,"Didn't find any nameservers.");
3286 return found
? 0 : -1;
3291 evdns_config_windows_nameservers(void)
3293 if (load_nameservers_with_getnetworkparams() == 0)
3295 return load_nameservers_from_registry();
3304 evdns_config_windows_nameservers();
3306 res
= evdns_resolv_conf_parse(DNS_OPTIONS_ALL
, "/etc/resolv.conf");
3313 evdns_err_to_string(int err
)
3316 case DNS_ERR_NONE
: return "no error";
3317 case DNS_ERR_FORMAT
: return "misformatted query";
3318 case DNS_ERR_SERVERFAILED
: return "server failed";
3319 case DNS_ERR_NOTEXIST
: return "name does not exist";
3320 case DNS_ERR_NOTIMPL
: return "query not implemented";
3321 case DNS_ERR_REFUSED
: return "refused";
3323 case DNS_ERR_TRUNCATED
: return "reply truncated or ill-formed";
3324 case DNS_ERR_UNKNOWN
: return "unknown";
3325 case DNS_ERR_TIMEOUT
: return "request timed out";
3326 case DNS_ERR_SHUTDOWN
: return "dns subsystem shut down";
3327 default: return "[Unknown error code]";
3332 evdns_shutdown(int fail_requests
)
3334 struct nameserver
*server
, *server_next
;
3335 struct search_domain
*dom
, *dom_next
;
3339 reply_callback(req_head
, 0, DNS_ERR_SHUTDOWN
, NULL
);
3340 request_finished(req_head
, &req_head
);
3342 while (req_waiting_head
) {
3344 reply_callback(req_waiting_head
, 0, DNS_ERR_SHUTDOWN
, NULL
);
3345 request_finished(req_waiting_head
, &req_waiting_head
);
3347 global_requests_inflight
= global_requests_waiting
= 0;
3349 for (server
= server_head
; server
; server
= server_next
) {
3350 server_next
= server
->next
;
3351 if (server
->socket
>= 0)
3352 CLOSE_SOCKET(server
->socket
);
3353 (void) event_del(&server
->event
);
3354 del_timeout_event(server
);
3357 if (server_next
== server_head
)
3361 global_good_nameservers
= 0;
3363 if (global_search_state
) {
3364 for (dom
= global_search_state
->head
; dom
; dom
= dom_next
) {
3365 dom_next
= dom
->next
;
3369 CLEAR(global_search_state
);
3370 mm_free(global_search_state
);
3371 global_search_state
= NULL
;
3373 evdns_log_fn
= NULL
;
3378 main_callback(int result
, char type
, int count
, int ttl
,
3379 void *addrs
, void *orig
) {
3380 char *n
= (char*)orig
;
3382 for (i
= 0; i
< count
; ++i
) {
3383 if (type
== DNS_IPv4_A
) {
3384 printf("%s: %s\n", n
, debug_ntoa(((u32
*)addrs
)[i
]));
3385 } else if (type
== DNS_PTR
) {
3386 printf("%s: %s\n", n
, ((char**)addrs
)[i
]);
3390 printf("%s: No answer (%d)\n", n
, result
);
3395 evdns_server_callback(struct evdns_server_request
*req
, void *data
)
3399 /* dummy; give 192.168.11.11 as an answer for all A questions,
3400 * give foo.bar.example.com as an answer for all PTR questions. */
3401 for (i
= 0; i
< req
->nquestions
; ++i
) {
3402 u32 ans
= htonl(0xc0a80b0bUL
);
3403 if (req
->questions
[i
]->type
== EVDNS_TYPE_A
&&
3404 req
->questions
[i
]->dns_question_class
== EVDNS_CLASS_INET
) {
3405 printf(" -- replying for %s (A)\n", req
->questions
[i
]->name
);
3406 r
= evdns_server_request_add_a_reply(req
, req
->questions
[i
]->name
,
3409 printf("eeep, didn't work.\n");
3410 } else if (req
->questions
[i
]->type
== EVDNS_TYPE_PTR
&&
3411 req
->questions
[i
]->dns_question_class
== EVDNS_CLASS_INET
) {
3412 printf(" -- replying for %s (PTR)\n", req
->questions
[i
]->name
);
3413 r
= evdns_server_request_add_ptr_reply(req
, NULL
, req
->questions
[i
]->name
,
3414 "foo.bar.example.com", 10);
3416 printf(" -- skipping %s [%d %d]\n", req
->questions
[i
]->name
,
3417 req
->questions
[i
]->type
, req
->questions
[i
]->dns_question_class
);
3421 r
= evdns_server_request_respond(req
, 0);
3423 printf("eeek, couldn't send reply.\n");
3427 logfn(int is_warn
, const char *msg
) {
3429 fprintf(stderr
, "%s\n", msg
);
3432 main(int c
, char **v
) {
3434 int reverse
= 0, verbose
= 1, servertest
= 0;
3436 fprintf(stderr
, "syntax: %s [-x] [-v] hostname\n", v
[0]);
3437 fprintf(stderr
, "syntax: %s [-servertest]\n", v
[0]);
3441 while (idx
< c
&& v
[idx
][0] == '-') {
3442 if (!strcmp(v
[idx
], "-x"))
3444 else if (!strcmp(v
[idx
], "-v"))
3446 else if (!strcmp(v
[idx
], "-servertest"))
3449 fprintf(stderr
, "Unknown option %s\n", v
[idx
]);
3454 evdns_set_log_fn(logfn
);
3455 evdns_resolv_conf_parse(DNS_OPTION_NAMESERVERS
, "/etc/resolv.conf");
3458 struct sockaddr_in my_addr
;
3459 sock
= socket(PF_INET
, SOCK_DGRAM
, 0);
3460 fcntl(sock
, F_SETFL
, O_NONBLOCK
);
3461 my_addr
.sin_family
= AF_INET
;
3462 my_addr
.sin_port
= htons(10053);
3463 my_addr
.sin_addr
.s_addr
= INADDR_ANY
;
3464 if (bind(sock
, (struct sockaddr
*)&my_addr
, sizeof(my_addr
))<0) {
3468 evdns_add_server_port(sock
, 0, evdns_server_callback
, NULL
);
3470 for (; idx
< c
; ++idx
) {
3472 struct in_addr addr
;
3473 if (!inet_aton(v
[idx
], &addr
)) {
3474 fprintf(stderr
, "Skipping non-IP %s\n", v
[idx
]);
3477 fprintf(stderr
, "resolving %s...\n",v
[idx
]);
3478 evdns_resolve_reverse(&addr
, 0, main_callback
, v
[idx
]);
3480 fprintf(stderr
, "resolving (fwd) %s...\n",v
[idx
]);
3481 evdns_resolve_ipv4(v
[idx
], 0, main_callback
, v
[idx
]);
3490 /* Local Variables: */
3492 /* c-basic-offset: 4 */
3493 /* indent-tabs-mode: t */