1 /* READ THIS COMMENT BEFORE HACKING THIS FILE.
3 * This eventdns.c copy has diverged a bit from Libevent's version, and it's
4 * no longer easy to resynchronize them. Once Tor requires Libevent 2.0, we
5 * will just dump this file and use Libevent's evdns code.
7 * Therefore, you probably shouldn't make any change here without making it to
8 * Libevent as well: it's not good for the implementation to diverge even
9 * more. Also, we can't shouldn't wantonly the API here (since Libevent APIs
10 * can't change in ways that break user behavior). Also, we shouldn't bother
11 * with cosmetic changes: the whole module is slated for demolition, so
12 * there's no point dusting the linebreaks or re-painting the parser.
14 * (We can't just drop the Libevent 2.0 evdns implementation in here instead,
15 * since it depends pretty heavily on parts of Libevent 2.0.)
19 * Adam Langley <agl@imperialviolet.org>
22 * This software is Public Domain. To view a copy of the public domain dedication,
23 * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
24 * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
26 * I ask and expect, but do not require, that all derivative works contain an
27 * attribution similar to:
28 * Parts developed by Adam Langley <agl@imperialviolet.org>
30 * You may wish to replace the word "Parts" with something else depending on
31 * the amount of original code.
33 * (Derivative works does not include programs which link against, run or include
34 * the source verbatim in their source distributions)
39 #include "eventdns_tor.h"
40 #include "../common/util.h"
41 #include <sys/types.h>
44 #ifndef DNS_USE_CPU_CLOCK_FOR_ID
45 #ifndef DNS_USE_GETTIMEOFDAY_FOR_ID
46 #ifndef DNS_USE_OPENSSL_FOR_ID
47 #error Must configure at least one id generation method.
48 #error Please see the documentation.
53 /* #define _POSIX_C_SOURCE 200507 */
56 #ifdef DNS_USE_CPU_CLOCK_FOR_ID
57 #ifdef DNS_USE_OPENSSL_FOR_ID
58 #error Multiple id options selected
60 #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
61 #error Multiple id options selected
66 #ifdef DNS_USE_OPENSSL_FOR_ID
67 #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
68 #error Multiple id options selected
70 #include <openssl/rand.h>
77 #ifdef HAVE_SYS_TIME_H
101 #include <winsock2.h>
102 #include <iphlpapi.h>
104 #include <sys/socket.h>
105 #include <netinet/in.h>
106 #include <arpa/inet.h>
109 #ifdef HAVE_NETINET_IN6_H
110 #include <netinet/in6.h>
114 typedef int socklen_t
;
117 #define EVDNS_LOG_DEBUG 0
118 #define EVDNS_LOG_WARN 1
120 #ifndef HOST_NAME_MAX
121 #define HOST_NAME_MAX 255
128 /* for debugging possible memory leaks. */
129 #define mm_malloc(x) tor_malloc(x)
130 #define mm_realloc(x,y) tor_realloc((x),(y))
131 #define mm_free(x) tor_free(x)
132 #define mm_strdup(x) tor_strdup(x)
133 #define _mm_free(x) _tor_free(x)
136 #define MIN(a,b) ((a)<(b)?(a):(b))
140 /* libevent doesn't work without this */
141 typedef uint8_t u_char
;
142 typedef unsigned int uint
;
152 #define MAX_ADDRS 4 /* maximum number of addresses from a single packet */
153 /* which we bother recording */
155 #define TYPE_A EVDNS_TYPE_A
157 #define TYPE_PTR EVDNS_TYPE_PTR
158 #define TYPE_AAAA EVDNS_TYPE_AAAA
160 #define CLASS_INET EVDNS_CLASS_INET
162 #define CLEAR(x) do { memset((x), 0xF0, sizeof(*(x))); } while(0)
164 struct evdns_request
{
165 u8
*request
; /* the dns packet data */
166 unsigned int request_len
;
168 int tx_count
; /* the number of times that this packet has been sent */
169 unsigned int request_type
; /* TYPE_PTR or TYPE_A */
170 void *user_pointer
; /* the pointer given to us for this request */
171 evdns_callback_type user_callback
;
172 struct nameserver
*ns
; /* the server which we last sent it */
174 /* elements used by the searching code */
176 struct search_state
*search_state
;
177 char *search_origname
; /* needs to be mm_free()ed */
180 /* these objects are kept in a circular list */
181 struct evdns_request
*next
, *prev
;
183 struct event timeout_event
;
185 u16 trans_id
; /* the transaction id */
186 char request_appended
; /* true if the request pointer is data which follows this struct */
187 char transmit_me
; /* needs to be transmitted */
190 #ifndef HAVE_STRUCT_IN6_ADDR
198 unsigned int have_answer
;
202 u32 addresses
[MAX_ADDRS
];
206 struct in6_addr addresses
[MAX_ADDRS
];
209 char name
[HOST_NAME_MAX
];
215 int socket
; /* a connected UDP socket */
216 struct sockaddr_storage address
;
217 int failed_times
; /* number of times which we have given this server a chance */
218 int timedout
; /* number of times in a row a request has timed out */
220 /* these objects are kept in a circular list */
221 struct nameserver
*next
, *prev
;
222 struct event timeout_event
; /* used to keep the timeout for */
223 /* when we next probe this server. */
224 /* Valid if state == 0 */
225 char state
; /* zero if we think that this server is down */
226 char choked
; /* true if we have an EAGAIN from this server's socket */
227 char write_waiting
; /* true if we are waiting for EV_WRITE events */
230 static struct evdns_request
*req_head
= NULL
, *req_waiting_head
= NULL
;
231 static struct nameserver
*server_head
= NULL
;
233 /* Represents a local port where we're listening for DNS requests. Right now, */
234 /* only UDP is supported. */
235 struct evdns_server_port
{
236 int socket
; /* socket we use to read queries and write replies. */
237 int refcnt
; /* reference count. */
238 char choked
; /* Are we currently blocked from writing? */
239 char closing
; /* Are we trying to close this port, pending writes? */
240 evdns_request_callback_fn_type user_callback
; /* Fn to handle requests */
241 void *user_data
; /* Opaque pointer passed to user_callback */
242 struct event event
; /* Read/write event */
243 /* circular list of replies that we want to write. */
244 struct server_request
*pending_replies
;
247 /* Represents part of a reply being built. (That is, a single RR.) */
248 struct server_reply_item
{
249 struct server_reply_item
*next
; /* next item in sequence. */
250 char *name
; /* name part of the RR */
251 u16 type
: 16; /* The RR type */
252 u16
class : 16; /* The RR class (usually CLASS_INET) */
253 u32 ttl
; /* The RR TTL */
254 char is_name
; /* True iff data is a label */
255 u16 datalen
; /* Length of data; -1 if data is a label */
256 void *data
; /* The contents of the RR */
259 /* Represents a request that we've received as a DNS server, and holds */
260 /* the components of the reply as we're constructing it. */
261 struct server_request
{
262 /* Pointers to the next and previous entries on the list of replies */
263 /* that we're waiting to write. Only set if we have tried to respond */
264 /* and gotten EAGAIN. */
265 struct server_request
*next_pending
;
266 struct server_request
*prev_pending
;
268 u16 trans_id
; /* Transaction id. */
269 struct evdns_server_port
*port
; /* Which port received this request on? */
270 struct sockaddr_storage addr
; /* Where to send the response */
271 socklen_t addrlen
; /* length of addr */
273 int n_answer
; /* how many answer RRs have been set? */
274 int n_authority
; /* how many authority RRs have been set? */
275 int n_additional
; /* how many additional RRs have been set? */
277 struct server_reply_item
*answer
; /* linked list of answer RRs */
278 struct server_reply_item
*authority
; /* linked list of authority RRs */
279 struct server_reply_item
*additional
; /* linked list of additional RRs */
281 /* Constructed response. Only set once we're ready to send a reply. */
282 /* Once this is set, the RR fields are cleared, and no more should be set. */
286 /* Caller-visible fields: flags, questions. */
287 struct evdns_server_request base
;
291 #define OFFSET_OF(st, member) ((off_t) (((char*)&((st*)0)->member)-(char*)0))
293 /* Given a pointer to an evdns_server_request, get the corresponding */
294 /* server_request. */
295 #define TO_SERVER_REQUEST(base_ptr) \
296 ((struct server_request*) \
297 (((char*)(base_ptr) - OFFSET_OF(struct server_request, base))))
299 /* The number of good nameservers that we have */
300 static int global_good_nameservers
= 0;
302 /* inflight requests are contained in the req_head list */
303 /* and are actually going out across the network */
304 static int global_requests_inflight
= 0;
305 /* requests which aren't inflight are in the waiting list */
306 /* and are counted here */
307 static int global_requests_waiting
= 0;
309 static int global_max_requests_inflight
= 64;
311 static struct timeval global_timeout
= {5, 0}; /* 5 seconds */
312 static int global_max_reissues
= 1; /* a reissue occurs when we get some errors from the server */
313 static int global_max_retransmits
= 3; /* number of times we'll retransmit a request which timed out */
314 /* number of timeouts in a row before we consider this server to be down */
315 static int global_max_nameserver_timeout
= 3;
317 /* true iff we should use the 0x20 hack. */
318 static int global_randomize_case
= 1;
320 /* These are the timeout values for nameservers. If we find a nameserver is down */
321 /* we try to probe it at intervals as given below. Values are in seconds. */
322 static const struct timeval global_nameserver_timeouts
[] = {{10, 0}, {60, 0}, {300, 0}, {900, 0}, {3600, 0}};
323 static const int global_nameserver_timeouts_length
= (int)(sizeof(global_nameserver_timeouts
)/sizeof(struct timeval
));
325 static struct nameserver
*nameserver_pick(void);
326 static void evdns_request_insert(struct evdns_request
*req
, struct evdns_request
**head
);
327 static void nameserver_ready_callback(int fd
, short events
, void *arg
);
328 static int evdns_transmit(void);
329 static int evdns_request_transmit(struct evdns_request
*req
);
330 static void nameserver_send_probe(struct nameserver
*const ns
);
331 static void search_request_finished(struct evdns_request
*const);
332 static int search_try_next(struct evdns_request
*const req
);
333 static int search_request_new(int type
, const char *const name
, int flags
, evdns_callback_type user_callback
, void *user_arg
);
334 static void evdns_requests_pump_waiting_queue(void);
335 static u16
transaction_id_pick(void);
336 static struct evdns_request
*request_new(int type
, const char *name
, int flags
, evdns_callback_type callback
, void *ptr
);
337 static void request_submit(struct evdns_request
*req
);
339 static int server_request_free(struct server_request
*req
);
340 static void server_request_free_answers(struct server_request
*req
);
341 static void server_port_free(struct evdns_server_port
*port
);
342 static void server_port_ready_callback(int fd
, short events
, void *arg
);
344 static int strtoint(const char *const str
);
350 int optval
, optvallen
=sizeof(optval
);
351 int err
= WSAGetLastError();
352 if (err
== WSAEWOULDBLOCK
&& sock
>= 0) {
353 if (getsockopt(sock
, SOL_SOCKET
, SO_ERROR
, (void*)&optval
,
363 error_is_eagain(int err
)
365 return err
== EAGAIN
|| err
== WSAEWOULDBLOCK
;
367 #define inet_aton(c, addr) tor_inet_aton((c), (addr))
368 #define CLOSE_SOCKET(x) closesocket(x)
370 #define last_error(sock) (errno)
371 #define error_is_eagain(err) ((err) == EAGAIN)
372 #define CLOSE_SOCKET(x) close(x)
375 #define ISSPACE(c) TOR_ISSPACE(c)
376 #define ISDIGIT(c) TOR_ISDIGIT(c)
377 #define ISALPHA(c) TOR_ISALPHA(c)
378 #define TOLOWER(c) TOR_TOLOWER(c)
379 #define TOUPPER(c) TOR_TOUPPER(c)
383 debug_ntoa(u32 address
)
386 u32 a
= ntohl(address
);
387 snprintf(buf
, sizeof(buf
), "%d.%d.%d.%d",
388 (int)(u8
)((a
>>24)&0xff),
389 (int)(u8
)((a
>>16)&0xff),
390 (int)(u8
)((a
>>8 )&0xff),
391 (int)(u8
)((a
)&0xff));
395 debug_ntop(const struct sockaddr
*sa
)
397 if (sa
->sa_family
== AF_INET
) {
398 struct sockaddr_in
*sin
= (struct sockaddr_in
*) sa
;
399 return debug_ntoa(sin
->sin_addr
.s_addr
);
401 if (sa
->sa_family
== AF_INET6
) {
402 /* Tor-specific. In libevent, add more check code. */
403 static char buf
[128];
404 struct sockaddr_in6
*sin
= (struct sockaddr_in6
*) sa
;
405 tor_inet_ntop(AF_INET6
, &sin
->sin6_addr
, buf
, sizeof(buf
));
412 static evdns_debug_log_fn_type evdns_log_fn
= NULL
;
415 evdns_set_log_fn(evdns_debug_log_fn_type fn
)
421 #define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3)))
423 #define EVDNS_LOG_CHECK
426 static void _evdns_log(int warn
, const char *fmt
, ...) EVDNS_LOG_CHECK
;
428 _evdns_log(int warn
, const char *fmt
, ...)
431 static char buf
[512];
436 _vsnprintf(buf
, sizeof(buf
), fmt
, args
);
438 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
440 buf
[sizeof(buf
)-1] = '\0';
441 evdns_log_fn(warn
, buf
);
445 #define log _evdns_log
448 sockaddr_eq(const struct sockaddr
*sa1
, const struct sockaddr
*sa2
,
451 if (sa1
->sa_family
!= sa2
->sa_family
)
453 if (sa1
->sa_family
== AF_INET
) {
454 const struct sockaddr_in
*sin1
, *sin2
;
455 sin1
= (const struct sockaddr_in
*)sa1
;
456 sin2
= (const struct sockaddr_in
*)sa2
;
457 if (sin1
->sin_addr
.s_addr
!= sin2
->sin_addr
.s_addr
)
459 else if (include_port
&& sin1
->sin_port
!= sin2
->sin_port
)
465 if (sa1
->sa_family
== AF_INET6
) {
466 const struct sockaddr_in6
*sin1
, *sin2
;
467 sin1
= (const struct sockaddr_in6
*)sa1
;
468 sin2
= (const struct sockaddr_in6
*)sa2
;
469 if (tor_memneq(sin1
->sin6_addr
.s6_addr
, sin2
->sin6_addr
.s6_addr
, 16))
471 else if (include_port
&& sin1
->sin6_port
!= sin2
->sin6_port
)
480 #define add_timeout_event(s, to) \
481 (event_add(&(s)->timeout_event, (to)))
482 #define del_timeout_event(s) \
483 (event_del(&(s)->timeout_event))
485 /* This walks the list of inflight requests to find the */
486 /* one with a matching transaction id. Returns NULL on */
488 static struct evdns_request
*
489 request_find_from_trans_id(u16 trans_id
) {
490 struct evdns_request
*req
= req_head
, *const started_at
= req_head
;
494 if (req
->trans_id
== trans_id
) return req
;
496 } while (req
!= started_at
);
502 /* a libevent callback function which is called when a nameserver */
503 /* has gone down and we want to test if it has came back to life yet */
505 nameserver_prod_callback(int fd
, short events
, void *arg
) {
506 struct nameserver
*const ns
= (struct nameserver
*) arg
;
510 nameserver_send_probe(ns
);
513 /* a libevent callback which is called when a nameserver probe (to see if */
514 /* it has come back to life) times out. We increment the count of failed_times */
515 /* and wait longer to send the next probe packet. */
517 nameserver_probe_failed(struct nameserver
*const ns
) {
518 const struct timeval
* timeout
;
519 del_timeout_event(ns
);
521 if (ns
->state
== 1) {
522 /* This can happen if the nameserver acts in a way which makes us mark */
523 /* it as bad and then starts sending good replies. */
528 &global_nameserver_timeouts
[MIN(ns
->failed_times
,
529 global_nameserver_timeouts_length
- 1)];
532 if (add_timeout_event(ns
, (struct timeval
*) timeout
) < 0) {
534 "Error from libevent when adding timer event for %s",
535 debug_ntop((struct sockaddr
*)&ns
->address
));
540 /* called when a nameserver has been deemed to have failed. For example, too */
541 /* many packets have timed out etc */
543 nameserver_failed(struct nameserver
*const ns
, const char *msg
) {
544 struct evdns_request
*req
, *started_at
;
545 /* if this nameserver has already been marked as failed */
546 /* then don't do anything */
547 if (!ns
->state
) return;
549 log(EVDNS_LOG_WARN
, "Nameserver %s has failed: %s",
550 debug_ntop((struct sockaddr
*)&ns
->address
), msg
);
551 global_good_nameservers
--;
552 assert(global_good_nameservers
>= 0);
553 if (global_good_nameservers
== 0) {
554 log(EVDNS_LOG_WARN
, "All nameservers have failed");
558 ns
->failed_times
= 1;
560 if (add_timeout_event(ns
, (struct timeval
*) &global_nameserver_timeouts
[0]) < 0) {
562 "Error from libevent when adding timer event for %s",
563 debug_ntop((struct sockaddr
*)&ns
->address
));
567 /* walk the list of inflight requests to see if any can be reassigned to */
568 /* a different server. Requests in the waiting queue don't have a */
569 /* nameserver assigned yet */
571 /* if we don't have *any* good nameservers then there's no point */
572 /* trying to reassign requests to one */
573 if (!global_good_nameservers
) return;
576 started_at
= req_head
;
579 if (req
->tx_count
== 0 && req
->ns
== ns
) {
580 /* still waiting to go out, can be moved */
581 /* to another server */
582 req
->ns
= nameserver_pick();
585 } while (req
!= started_at
);
590 nameserver_up(struct nameserver
*const ns
) {
591 if (ns
->state
) return;
592 log(EVDNS_LOG_WARN
, "Nameserver %s is back up",
593 debug_ntop((struct sockaddr
*)&ns
->address
));
594 del_timeout_event(ns
);
596 ns
->failed_times
= 0;
598 global_good_nameservers
++;
602 request_trans_id_set(struct evdns_request
*const req
, const u16 trans_id
) {
603 req
->trans_id
= trans_id
;
604 *((u16
*) req
->request
) = htons(trans_id
);
607 /* Called to remove a request from a list and dealloc it. */
608 /* head is a pointer to the head of the list it should be */
609 /* removed from or NULL if the request isn't in a list. */
611 request_finished(struct evdns_request
*const req
, struct evdns_request
**head
) {
613 if (req
->next
== req
) {
614 /* only item in the list */
617 req
->next
->prev
= req
->prev
;
618 req
->prev
->next
= req
->next
;
619 if (*head
== req
) *head
= req
->next
;
623 log(EVDNS_LOG_DEBUG
, "Removing timeout for request %lx",
624 (unsigned long) req
);
625 del_timeout_event(req
);
627 search_request_finished(req
);
628 global_requests_inflight
--;
630 if (!req
->request_appended
) {
631 /* need to free the request data on it's own */
632 mm_free(req
->request
);
634 /* the request data is appended onto the header */
635 /* so everything gets mm_free()ed when we: */
641 evdns_requests_pump_waiting_queue();
644 /* This is called when a server returns a funny error code. */
645 /* We try the request again with another server. */
649 /* 1 failed/reissue is pointless */
651 request_reissue(struct evdns_request
*req
) {
652 const struct nameserver
*const last_ns
= req
->ns
;
653 /* the last nameserver should have been marked as failing */
654 /* by the caller of this function, therefore pick will try */
655 /* not to return it */
656 req
->ns
= nameserver_pick();
657 if (req
->ns
== last_ns
) {
658 /* ... but pick did return it */
659 /* not a lot of point in trying again with the */
664 req
->reissue_count
++;
666 req
->transmit_me
= 1;
671 /* this function looks for space on the inflight queue and promotes */
672 /* requests from the waiting queue if it can. */
674 evdns_requests_pump_waiting_queue(void) {
675 while (global_requests_inflight
< global_max_requests_inflight
&&
676 global_requests_waiting
) {
677 struct evdns_request
*req
;
678 /* move a request from the waiting queue to the inflight queue */
679 assert(req_waiting_head
);
680 if (req_waiting_head
->next
== req_waiting_head
) {
681 /* only one item in the queue */
682 req
= req_waiting_head
;
683 req_waiting_head
= NULL
;
685 req
= req_waiting_head
;
686 req
->next
->prev
= req
->prev
;
687 req
->prev
->next
= req
->next
;
688 req_waiting_head
= req
->next
;
691 global_requests_waiting
--;
692 global_requests_inflight
++;
694 req
->ns
= nameserver_pick();
695 request_trans_id_set(req
, transaction_id_pick());
697 evdns_request_insert(req
, &req_head
);
698 evdns_request_transmit(req
);
704 reply_callback(struct evdns_request
*const req
, u32 ttl
, u32 err
, struct reply
*reply
) {
705 switch (req
->request_type
) {
708 req
->user_callback(DNS_ERR_NONE
, DNS_IPv4_A
,
709 reply
->data
.a
.addrcount
, ttl
,
710 reply
->data
.a
.addresses
,
713 req
->user_callback(err
, 0, 0, 0, NULL
, req
->user_pointer
);
717 char *name
= reply
->data
.ptr
.name
;
718 req
->user_callback(DNS_ERR_NONE
, DNS_PTR
, 1, ttl
,
719 &name
, req
->user_pointer
);
721 req
->user_callback(err
, 0, 0, 0, NULL
,
727 req
->user_callback(DNS_ERR_NONE
, DNS_IPv6_AAAA
,
728 reply
->data
.aaaa
.addrcount
, ttl
,
729 reply
->data
.aaaa
.addresses
,
732 req
->user_callback(err
, 0, 0, 0, NULL
, req
->user_pointer
);
738 /* this processes a parsed reply packet */
740 reply_handle(struct evdns_request
*const req
, u16 flags
, u32 ttl
, struct reply
*reply
) {
742 static const int error_codes
[] = {DNS_ERR_FORMAT
, DNS_ERR_SERVERFAILED
, DNS_ERR_NOTEXIST
, DNS_ERR_NOTIMPL
, DNS_ERR_REFUSED
};
744 if (flags
& 0x020f || !reply
|| !reply
->have_answer
) {
745 /* there was an error */
746 if (flags
& 0x0200) {
747 error
= DNS_ERR_TRUNCATED
;
749 u16 error_code
= (flags
& 0x000f) - 1;
750 if (error_code
> 4) {
751 error
= DNS_ERR_UNKNOWN
;
753 error
= error_codes
[error_code
];
758 case DNS_ERR_NOTIMPL
:
759 case DNS_ERR_REFUSED
:
760 /* we regard these errors as marking a bad nameserver */
761 if (req
->reissue_count
< global_max_reissues
) {
763 snprintf(msg
, sizeof(msg
), "Bad response %d (%s)",
764 error
, evdns_err_to_string(error
));
765 nameserver_failed(req
->ns
, msg
);
766 if (!request_reissue(req
)) return;
769 case DNS_ERR_SERVERFAILED
:
770 /* rcode 2 (servfailed) sometimes means "we are broken" and
771 * sometimes (with some binds) means "that request was very
772 * confusing." Treat this as a timeout, not a failure.
774 /*XXXX refactor the parts of */
775 log(EVDNS_LOG_DEBUG
, "Got a SERVERFAILED from nameserver %s; "
776 "will allow the request to time out.",
777 debug_ntop((struct sockaddr
*)&req
->ns
->address
));
780 /* we got a good reply from the nameserver */
781 nameserver_up(req
->ns
);
784 if (req
->search_state
&& req
->request_type
!= TYPE_PTR
) {
785 /* if we have a list of domains to search in, try the next one */
786 if (!search_try_next(req
)) {
787 /* a new request was issued so this request is finished and */
788 /* the user callback will be made when that request (or a */
789 /* child of it) finishes. */
790 request_finished(req
, &req_head
);
795 /* all else failed. Pass the failure up */
796 reply_callback(req
, 0, error
, NULL
);
797 request_finished(req
, &req_head
);
799 /* all ok, tell the user */
800 reply_callback(req
, ttl
, 0, reply
);
801 nameserver_up(req
->ns
);
802 request_finished(req
, &req_head
);
807 name_parse(u8
*packet
, int length
, int *idx
, char *name_out
, size_t name_out_len
) {
811 #define GET32(x) do { if (j + 4 > length) goto err; memcpy(&_t32, packet + j, 4); j += 4; x = ntohl(_t32); } while(0)
812 #define GET16(x) do { if (j + 2 > length) goto err; memcpy(&_t, packet + j, 2); j += 2; x = ntohs(_t); } while(0)
813 #define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while(0)
816 const char *const end
= name_out
+ name_out_len
;
818 /* Normally, names are a series of length prefixed strings terminated */
819 /* with a length of 0 (the lengths are u8's < 63). */
820 /* However, the length can start with a pair of 1 bits and that */
821 /* means that the next 14 bits are a pointer within the current */
826 if (j
>= length
) return -1;
828 if (!label_len
) break;
829 if (label_len
& 0xc0) {
832 if (name_end
< 0) name_end
= j
;
833 j
= (((int)label_len
& 0x3f) << 8) + ptr_low
;
834 /* Make sure that the target offset is in-bounds. */
835 if (j
< 0 || j
>= length
) return -1;
836 /* If we've jumped more times than there are characters in the
837 * message, we must have a loop. */
838 if (++ptr_count
> length
) return -1;
841 if (label_len
> 63) return -1;
842 if (cp
!= name_out
) {
843 if (cp
+ 1 >= end
) return -1;
846 if (cp
+ label_len
>= end
) return -1;
847 memcpy(cp
, packet
+ j
, label_len
);
851 if (cp
>= end
) return -1;
862 /* parses a raw reply from a nameserver. */
864 reply_parse(u8
*packet
, int length
) {
865 int j
= 0; /* index into packet */
867 u16 _t
; /* used by the macros */
868 u32 _t32
; /* used by the macros */
869 char tmp_name
[256], cmp_name
[256]; /* used by the macros */
871 u16 trans_id
, questions
, answers
, authority
, additional
, datalength
;
873 u32 ttl
, ttl_r
= 0xffffffff;
875 struct evdns_request
*req
= NULL
;
877 int name_matches
= 0;
885 (void) authority
; /* suppress "unused variable" warnings. */
886 (void) additional
; /* suppress "unused variable" warnings. */
888 req
= request_find_from_trans_id(trans_id
);
889 /* if no request, can't do anything. */
892 memset(&reply
, 0, sizeof(reply
));
894 /* If it's not an answer, it doesn't go with any of our requests. */
895 if (!(flags
& 0x8000)) return -1; /* must be an answer */
896 if (flags
& 0x020f) {
897 /* there was an error */
900 /* if (!answers) return; */ /* must have an answer of some form */
902 /* This macro skips a name in the DNS reply. */
904 do { tmp_name[0] = '\0'; \
905 if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
909 do { tmp_name[0] = '\0'; \
910 cmp_name[0] = '\0'; \
912 if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
914 if (name_parse(req->request, req->request_len, &k, cmp_name, sizeof(cmp_name))<0) \
916 if (global_randomize_case) { \
917 if (strcmp(tmp_name, cmp_name) == 0) \
918 name_matches = 1; /* we ignore mismatching names */ \
920 if (strcasecmp(tmp_name, cmp_name) == 0) \
925 reply
.type
= req
->request_type
;
927 /* skip over each question in the reply */
928 for (i
= 0; i
< questions
; ++i
) {
929 /* the question looks like
930 * <label:name><u16:type><u16:class>
934 if (j
>= length
) goto err
;
940 /* now we have the answer section which looks like
941 * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
944 for (i
= 0; i
< answers
; ++i
) {
953 if (type
== TYPE_A
&& class == CLASS_INET
) {
954 int addrcount
, addrtocopy
;
955 if (req
->request_type
!= TYPE_A
) {
956 j
+= datalength
; continue;
958 if ((datalength
& 3) != 0) /* not an even number of As. */
960 addrcount
= datalength
>> 2;
961 addrtocopy
= MIN(MAX_ADDRS
- reply
.data
.a
.addrcount
, (unsigned)addrcount
);
963 ttl_r
= MIN(ttl_r
, ttl
);
964 /* we only bother with the first four addresses. */
965 if (j
+ 4*addrtocopy
> length
) goto err
;
966 memcpy(&reply
.data
.a
.addresses
[reply
.data
.a
.addrcount
],
967 packet
+ j
, 4*addrtocopy
);
968 reply
.data
.a
.addrcount
+= addrtocopy
;
969 reply
.have_answer
= 1;
970 if (reply
.data
.a
.addrcount
== MAX_ADDRS
) break;
972 } else if (type
== TYPE_PTR
&& class == CLASS_INET
) {
973 if (req
->request_type
!= TYPE_PTR
) {
974 j
+= datalength
; continue;
977 strlcpy(reply
.data
.ptr
.name
, tmp_name
,
978 sizeof(reply
.data
.ptr
.name
));
979 ttl_r
= MIN(ttl_r
, ttl
);
980 reply
.have_answer
= 1;
982 } else if (type
== TYPE_AAAA
&& class == CLASS_INET
) {
983 int addrcount
, addrtocopy
;
984 if (req
->request_type
!= TYPE_AAAA
) {
985 j
+= datalength
; continue;
987 if ((datalength
& 15) != 0) /* not an even number of AAAAs. */
989 addrcount
= datalength
>> 4; /* each address is 16 bytes long */
990 addrtocopy
= MIN(MAX_ADDRS
- reply
.data
.aaaa
.addrcount
, (unsigned)addrcount
);
991 ttl_r
= MIN(ttl_r
, ttl
);
993 /* we only bother with the first four addresses. */
994 if (j
+ 16*addrtocopy
> length
) goto err
;
995 memcpy(&reply
.data
.aaaa
.addresses
[reply
.data
.aaaa
.addrcount
],
996 packet
+ j
, 16*addrtocopy
);
997 reply
.data
.aaaa
.addrcount
+= addrtocopy
;
998 reply
.have_answer
= 1;
999 if (reply
.data
.aaaa
.addrcount
== MAX_ADDRS
) break;
1002 /* skip over any other type of resource */
1007 reply_handle(req
, flags
, ttl_r
, &reply
);
1011 reply_handle(req
, flags
, 0, NULL
);
1015 /* Parse a raw request (packet,length) sent to a nameserver port (port) from */
1016 /* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
1019 request_parse(u8
*packet
, ssize_t length
, struct evdns_server_port
*port
, struct sockaddr
*addr
, socklen_t addrlen
)
1021 int j
= 0; /* index into packet */
1022 u16 _t
; /* used by the macros */
1023 char tmp_name
[256]; /* used by the macros */
1026 u16 trans_id
, flags
, questions
, answers
, authority
, additional
;
1027 struct server_request
*server_req
= NULL
;
1029 /* Get the header fields */
1040 if (flags
& 0x8000) return -1; /* Must not be an answer. */
1041 flags
&= 0x0110; /* Only RD and CD get preserved. */
1043 if (length
> INT_MAX
)
1046 server_req
= mm_malloc(sizeof(struct server_request
));
1047 if (server_req
== NULL
) return -1;
1048 memset(server_req
, 0, sizeof(struct server_request
));
1050 server_req
->trans_id
= trans_id
;
1051 memcpy(&server_req
->addr
, addr
, addrlen
);
1052 server_req
->addrlen
= addrlen
;
1054 server_req
->base
.flags
= flags
;
1055 server_req
->base
.nquestions
= 0;
1056 server_req
->base
.questions
= mm_malloc(sizeof(struct evdns_server_question
*) * questions
);
1057 if (server_req
->base
.questions
== NULL
)
1060 for (i
= 0; i
< questions
; ++i
) {
1062 struct evdns_server_question
*q
;
1064 if (name_parse(packet
, (int)length
, &j
, tmp_name
, sizeof(tmp_name
))<0)
1068 namelen
= strlen(tmp_name
);
1069 q
= mm_malloc(sizeof(struct evdns_server_question
) + namelen
);
1073 q
->dns_question_class
= class;
1074 memcpy(q
->name
, tmp_name
, namelen
+1);
1075 server_req
->base
.questions
[server_req
->base
.nquestions
++] = q
;
1078 /* Ignore answers, authority, and additional. */
1080 server_req
->port
= port
;
1083 /* Only standard queries are supported. */
1084 if (flags
& 0x7800) {
1085 evdns_server_request_respond(&(server_req
->base
), DNS_ERR_NOTIMPL
);
1089 port
->user_callback(&(server_req
->base
), port
->user_data
);
1094 if (server_req
->base
.questions
) {
1095 for (i
= 0; i
< server_req
->base
.nquestions
; ++i
)
1096 mm_free(server_req
->base
.questions
[i
]);
1097 mm_free(server_req
->base
.questions
);
1100 mm_free(server_req
);
1111 default_transaction_id_fn(void)
1114 #ifdef DNS_USE_CPU_CLOCK_FOR_ID
1116 #ifdef CLOCK_MONOTONIC
1117 if (clock_gettime(CLOCK_MONOTONIC
, &ts
) == -1)
1119 if (clock_gettime(CLOCK_REALTIME
, &ts
) == -1)
1121 event_err(1, "clock_gettime");
1122 trans_id
= ts
.tv_nsec
& 0xffff;
1125 #ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
1127 gettimeofday(&tv
, NULL
);
1128 trans_id
= tv
.tv_usec
& 0xffff;
1131 #ifdef DNS_USE_OPENSSL_FOR_ID
1132 if (RAND_pseudo_bytes((u8
*) &trans_id
, 2) == -1) {
1133 /* in the case that the RAND call fails we back */
1134 /* down to using gettimeofday. */
1137 gettimeofday(&tv, NULL);
1138 trans_id = tv.tv_usec & 0xffff;
1143 return (unsigned short) trans_id
;
1146 static uint16_t (*trans_id_function
)(void) = default_transaction_id_fn
;
1149 default_random_bytes_fn(char *buf
, size_t n
)
1152 for (i
= 0; i
< n
; i
+= 2) {
1153 u16 tid
= trans_id_function();
1154 buf
[i
] = (tid
>> 8) & 0xff;
1156 buf
[i
+1] = tid
& 0xff;
1160 static void (*rand_bytes_function
)(char *buf
, size_t n
) =
1161 default_random_bytes_fn
;
1164 trans_id_from_random_bytes_fn(void)
1167 rand_bytes_function((char*) &tid
, sizeof(tid
));
1172 evdns_set_transaction_id_fn(uint16_t (*fn
)(void))
1175 trans_id_function
= fn
;
1177 trans_id_function
= default_transaction_id_fn
;
1178 rand_bytes_function
= default_random_bytes_fn
;
1182 evdns_set_random_bytes_fn(void (*fn
)(char *, size_t))
1184 rand_bytes_function
= fn
;
1185 trans_id_function
= trans_id_from_random_bytes_fn
;
1188 /* Try to choose a strong transaction id which isn't already in flight */
1190 transaction_id_pick(void) {
1192 const struct evdns_request
*req
= req_head
, *started_at
;
1193 u16 trans_id
= trans_id_function();
1195 if (trans_id
== 0xffff) continue;
1196 /* now check to see if that id is already inflight */
1197 req
= started_at
= req_head
;
1200 if (req
->trans_id
== trans_id
) break;
1202 } while (req
!= started_at
);
1204 /* we didn't find it, so this is a good id */
1205 if (req
== started_at
) return trans_id
;
1209 /* choose a namesever to use. This function will try to ignore */
1210 /* nameservers which we think are down and load balance across the rest */
1211 /* by updating the server_head global each time. */
1212 static struct nameserver
*
1213 nameserver_pick(void) {
1214 struct nameserver
*started_at
= server_head
, *picked
;
1215 if (!server_head
) return NULL
;
1217 /* if we don't have any good nameservers then there's no */
1218 /* point in trying to find one. */
1219 if (!global_good_nameservers
) {
1220 server_head
= server_head
->next
;
1224 /* remember that nameservers are in a circular list */
1226 if (server_head
->state
) {
1227 /* we think this server is currently good */
1228 picked
= server_head
;
1229 server_head
= server_head
->next
;
1233 server_head
= server_head
->next
;
1234 if (server_head
== started_at
) {
1235 /* all the nameservers seem to be down */
1236 /* so we just return this one and hope for the */
1238 assert(global_good_nameservers
== 0);
1239 picked
= server_head
;
1240 server_head
= server_head
->next
;
1246 /* this is called when a namesever socket is ready for reading */
1248 nameserver_read(struct nameserver
*ns
) {
1249 struct sockaddr_storage ss
;
1250 struct sockaddr
*sa
= (struct sockaddr
*) &ss
;
1251 socklen_t addrlen
= sizeof(ss
);
1256 (int)recvfrom(ns
->socket
, (void*)packet
,
1257 (socklen_t
)sizeof(packet
), 0,
1260 int err
= last_error(ns
->socket
);
1261 if (error_is_eagain(err
)) return;
1262 nameserver_failed(ns
, tor_socket_strerror(err
));
1265 /* XXX Match port too? */
1266 if (!sockaddr_eq(sa
, (struct sockaddr
*)&ns
->address
, 0)) {
1268 "Address mismatch on received DNS packet. Address was %s",
1273 reply_parse(packet
, r
);
1277 /* Read a packet from a DNS client on a server port s, parse it, and */
1278 /* act accordingly. */
1280 server_port_read(struct evdns_server_port
*s
) {
1282 struct sockaddr_storage addr
;
1287 addrlen
= (socklen_t
)sizeof(struct sockaddr_storage
);
1288 r
= recvfrom(s
->socket
, (void*)packet
, sizeof(packet
), 0,
1289 (struct sockaddr
*) &addr
, &addrlen
);
1291 int err
= last_error(s
->socket
);
1292 if (error_is_eagain(err
)) return;
1293 log(EVDNS_LOG_WARN
, "Error %s (%d) while reading request.",
1294 tor_socket_strerror(err
), err
);
1297 request_parse(packet
, r
, s
, (struct sockaddr
*) &addr
, addrlen
);
1301 /* Try to write all pending replies on a given DNS server port. */
1303 server_port_flush(struct evdns_server_port
*port
)
1305 struct server_request
*req
= port
->pending_replies
;
1307 ssize_t r
= sendto(port
->socket
, req
->response
, req
->response_len
, 0,
1308 (struct sockaddr
*) &req
->addr
, (socklen_t
)req
->addrlen
);
1310 int err
= last_error(port
->socket
);
1311 if (error_is_eagain(err
))
1313 log(EVDNS_LOG_WARN
, "Error %s (%d) while writing response to port; dropping", tor_socket_strerror(err
), err
);
1315 if (server_request_free(req
)) {
1316 /* we released the last reference to req->port. */
1319 assert(port
->pending_replies
!= req
);
1320 req
= port
->pending_replies
;
1324 /* We have no more pending requests; stop listening for 'writeable' events. */
1325 (void) event_del(&port
->event
);
1326 CLEAR(&port
->event
);
1327 event_set(&port
->event
, port
->socket
, EV_READ
| EV_PERSIST
,
1328 server_port_ready_callback
, port
);
1329 if (event_add(&port
->event
, NULL
) < 0) {
1330 log(EVDNS_LOG_WARN
, "Error from libevent when adding event for DNS server.");
1335 /* set if we are waiting for the ability to write to this server. */
1336 /* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
1337 /* we stop these events. */
1339 nameserver_write_waiting(struct nameserver
*ns
, char waiting
) {
1340 if (ns
->write_waiting
== waiting
) return;
1342 ns
->write_waiting
= waiting
;
1343 (void) event_del(&ns
->event
);
1345 event_set(&ns
->event
, ns
->socket
, EV_READ
| (waiting
? EV_WRITE
: 0) | EV_PERSIST
,
1346 nameserver_ready_callback
, ns
);
1347 if (event_add(&ns
->event
, NULL
) < 0) {
1348 log(EVDNS_LOG_WARN
, "Error from libevent when adding event for %s",
1349 debug_ntop((struct sockaddr
*)&ns
->address
));
1354 /* a callback function. Called by libevent when the kernel says that */
1355 /* a nameserver socket is ready for writing or reading */
1357 nameserver_ready_callback(int fd
, short events
, void *arg
) {
1358 struct nameserver
*ns
= (struct nameserver
*) arg
;
1361 if (events
& EV_WRITE
) {
1363 if (!evdns_transmit()) {
1364 nameserver_write_waiting(ns
, 0);
1367 if (events
& EV_READ
) {
1368 nameserver_read(ns
);
1372 /* a callback function. Called by libevent when the kernel says that */
1373 /* a server socket is ready for writing or reading. */
1375 server_port_ready_callback(int fd
, short events
, void *arg
) {
1376 struct evdns_server_port
*port
= (struct evdns_server_port
*) arg
;
1379 if (events
& EV_WRITE
) {
1381 server_port_flush(port
);
1383 if (events
& EV_READ
) {
1384 server_port_read(port
);
1388 /* This is an inefficient representation; only use it via the dnslabel_table_*
1389 * functions, so that is can be safely replaced with something smarter later. */
1390 #define MAX_LABELS 128
1391 /* Structures used to implement name compression */
1392 struct dnslabel_entry
{ char *v
; off_t pos
; };
1393 struct dnslabel_table
{
1394 int n_labels
; /* number of current entries */
1395 /* map from name to position in message */
1396 struct dnslabel_entry labels
[MAX_LABELS
];
1399 /* Initialize dnslabel_table. */
1401 dnslabel_table_init(struct dnslabel_table
*table
)
1403 table
->n_labels
= 0;
1406 /* Free all storage held by table, but not the table itself. */
1408 dnslabel_clear(struct dnslabel_table
*table
)
1411 for (i
= 0; i
< table
->n_labels
; ++i
)
1412 mm_free(table
->labels
[i
].v
);
1413 table
->n_labels
= 0;
1416 /* return the position of the label in the current message, or -1 if the label */
1417 /* hasn't been used yet. */
1419 dnslabel_table_get_pos(const struct dnslabel_table
*table
, const char *label
)
1422 for (i
= 0; i
< table
->n_labels
; ++i
) {
1423 if (!strcmp(label
, table
->labels
[i
].v
)) {
1424 off_t pos
= table
->labels
[i
].pos
;
1433 /* remember that we've used the label at position pos */
1435 dnslabel_table_add(struct dnslabel_table
*table
, const char *label
, off_t pos
)
1439 if (table
->n_labels
== MAX_LABELS
)
1441 v
= mm_strdup(label
);
1444 p
= table
->n_labels
++;
1445 table
->labels
[p
].v
= v
;
1446 table
->labels
[p
].pos
= pos
;
1451 /* Converts a string to a length-prefixed set of DNS labels, starting */
1452 /* at buf[j]. name and buf must not overlap. name_len should be the length */
1453 /* of name. table is optional, and is used for compression. */
1455 /* Input: abc.def */
1456 /* Output: <3>abc<3>def<0> */
1458 /* Returns the first index after the encoded name, or negative on error. */
1459 /* -1 label was > 63 bytes */
1460 /* -2 name too long to fit in buffer. */
1463 dnsname_to_labels(u8
*const buf
, size_t buf_len
, off_t j
,
1464 const char *name
, const size_t name_len
,
1465 struct dnslabel_table
*table
) {
1466 const char *end
= name
+ name_len
;
1470 #define APPEND16(x) do { \
1471 if (j + 2 > (off_t)buf_len) \
1474 memcpy(buf + j, &_t, 2); \
1477 #define APPEND32(x) do { \
1478 if (j + 4 > (off_t)buf_len) \
1481 memcpy(buf + j, &_t32, 4); \
1485 if (name_len
> 255) return -2;
1488 const char *const start
= name
;
1489 if (table
&& (ref
= dnslabel_table_get_pos(table
, name
)) >= 0) {
1490 APPEND16(ref
| 0xc000);
1493 name
= strchr(name
, '.');
1495 const size_t label_len
= end
- start
;
1496 if (label_len
> 63) return -1;
1497 if ((size_t)(j
+label_len
+1) > buf_len
) return -2;
1498 if (table
) dnslabel_table_add(table
, start
, j
);
1499 buf
[j
++] = (uint8_t)label_len
;
1501 memcpy(buf
+ j
, start
, label_len
);
1505 /* append length of the label. */
1506 const size_t label_len
= name
- start
;
1507 if (label_len
> 63) return -1;
1508 if ((size_t)(j
+label_len
+1) > buf_len
) return -2;
1509 if (table
) dnslabel_table_add(table
, start
, j
);
1510 buf
[j
++] = (uint8_t)label_len
;
1512 memcpy(buf
+ j
, start
, name
- start
);
1514 /* hop over the '.' */
1519 /* the labels must be terminated by a 0. */
1520 /* It's possible that the name ended in a . */
1521 /* in which case the zero is already there */
1522 if (!j
|| buf
[j
-1]) buf
[j
++] = 0;
1528 /* Finds the length of a dns request for a DNS name of the given */
1529 /* length. The actual request may be smaller than the value returned */
1532 evdns_request_len(const size_t name_len
) {
1533 return 96 + /* length of the DNS standard header */
1535 4; /* space for the resource type */
1538 /* build a dns request packet into buf. buf should be at least as long */
1539 /* as evdns_request_len told you it should be. */
1541 /* Returns the amount of space used. Negative on error. */
1543 evdns_request_data_build(const char *const name
, const size_t name_len
,
1544 const u16 trans_id
, const u16 type
, const u16
class,
1545 u8
*const buf
, size_t buf_len
) {
1546 off_t j
= 0; /* current offset into buf */
1547 u16 _t
; /* used by the macros */
1550 APPEND16(0x0100); /* standard query, recusion needed */
1551 APPEND16(1); /* one question */
1552 APPEND16(0); /* no answers */
1553 APPEND16(0); /* no authority */
1554 APPEND16(0); /* no additional */
1556 j
= dnsname_to_labels(buf
, buf_len
, j
, name
, name_len
, NULL
);
1569 /* exported function */
1570 struct evdns_server_port
*
1571 evdns_add_server_port(tor_socket_t socket
, int is_tcp
, evdns_request_callback_fn_type cb
, void *user_data
)
1573 struct evdns_server_port
*port
;
1574 if (!(port
= mm_malloc(sizeof(struct evdns_server_port
))))
1576 memset(port
, 0, sizeof(struct evdns_server_port
));
1578 assert(!is_tcp
); /* TCP sockets not yet implemented */
1579 port
->socket
= socket
;
1583 port
->user_callback
= cb
;
1584 port
->user_data
= user_data
;
1585 port
->pending_replies
= NULL
;
1587 event_set(&port
->event
, port
->socket
, EV_READ
| EV_PERSIST
,
1588 server_port_ready_callback
, port
);
1589 if (event_add(&port
->event
, NULL
)<0) {
1596 /* exported function */
1598 evdns_close_server_port(struct evdns_server_port
*port
)
1601 if (--port
->refcnt
== 0)
1602 server_port_free(port
);
1605 /* exported function */
1607 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
)
1609 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1610 struct server_reply_item
**itemp
, *item
;
1613 if (req
->response
) /* have we already answered? */
1617 case EVDNS_ANSWER_SECTION
:
1618 itemp
= &req
->answer
;
1619 countp
= &req
->n_answer
;
1621 case EVDNS_AUTHORITY_SECTION
:
1622 itemp
= &req
->authority
;
1623 countp
= &req
->n_authority
;
1625 case EVDNS_ADDITIONAL_SECTION
:
1626 itemp
= &req
->additional
;
1627 countp
= &req
->n_additional
;
1633 itemp
= &((*itemp
)->next
);
1635 item
= mm_malloc(sizeof(struct server_reply_item
));
1640 if (!(item
->name
= mm_strdup(name
))) {
1646 item
->class = class;
1648 item
->is_name
= is_name
!= 0;
1652 if (item
->is_name
) {
1653 if (!(item
->data
= mm_strdup(data
))) {
1654 mm_free(item
->name
);
1659 item
->datalen
= (u16
)-1;
1661 if (!(item
->data
= mm_malloc(datalen
))) {
1662 mm_free(item
->name
);
1667 item
->datalen
= datalen
;
1668 memcpy(item
->data
, data
, datalen
);
1677 /* exported function */
1679 evdns_server_request_add_a_reply(struct evdns_server_request
*req
, const char *name
, int n
, const void *addrs
, int ttl
)
1681 return evdns_server_request_add_reply(
1682 req
, EVDNS_ANSWER_SECTION
, name
, TYPE_A
, CLASS_INET
,
1683 ttl
, n
*4, 0, addrs
);
1686 /* exported function */
1688 evdns_server_request_add_aaaa_reply(struct evdns_server_request
*req
, const char *name
, int n
, const void *addrs
, int ttl
)
1690 return evdns_server_request_add_reply(
1691 req
, EVDNS_ANSWER_SECTION
, name
, TYPE_AAAA
, CLASS_INET
,
1692 ttl
, n
*16, 0, addrs
);
1695 /* exported function */
1697 evdns_server_request_add_ptr_reply(struct evdns_server_request
*req
, struct in_addr
*in
, const char *inaddr_name
, const char *hostname
, int ttl
)
1701 assert(in
|| inaddr_name
);
1702 assert(!(in
&& inaddr_name
));
1704 a
= ntohl(in
->s_addr
);
1705 snprintf(buf
, sizeof(buf
), "%d.%d.%d.%d.in-addr.arpa",
1706 (int)(u8
)((a
)&0xff),
1707 (int)(u8
)((a
>>8 )&0xff),
1708 (int)(u8
)((a
>>16)&0xff),
1709 (int)(u8
)((a
>>24)&0xff));
1712 return evdns_server_request_add_reply(
1713 req
, EVDNS_ANSWER_SECTION
, inaddr_name
, TYPE_PTR
, CLASS_INET
,
1714 ttl
, -1, 1, hostname
);
1717 /* exported function */
1719 evdns_server_request_add_cname_reply(struct evdns_server_request
*req
, const char *name
, const char *cname
, int ttl
)
1721 return evdns_server_request_add_reply(
1722 req
, EVDNS_ANSWER_SECTION
, name
, TYPE_CNAME
, CLASS_INET
,
1728 evdns_server_request_format_response(struct server_request
*req
, int err
)
1730 unsigned char buf
[1500];
1731 size_t buf_len
= sizeof(buf
);
1737 struct dnslabel_table table
;
1739 if (err
< 0 || err
> 15) return -1;
1741 /* Set response bit and error code; copy OPCODE and RD fields from
1742 * question; copy RA and AA if set by caller. */
1743 flags
= req
->base
.flags
;
1744 flags
|= (0x8000 | err
);
1746 dnslabel_table_init(&table
);
1747 APPEND16(req
->trans_id
);
1749 APPEND16(req
->base
.nquestions
);
1750 APPEND16(req
->n_answer
);
1751 APPEND16(req
->n_authority
);
1752 APPEND16(req
->n_additional
);
1754 /* Add questions. */
1755 for (i
=0; i
< req
->base
.nquestions
; ++i
) {
1756 const char *s
= req
->base
.questions
[i
]->name
;
1757 j
= dnsname_to_labels(buf
, buf_len
, j
, s
, strlen(s
), &table
);
1759 dnslabel_clear(&table
);
1762 APPEND16(req
->base
.questions
[i
]->type
);
1763 APPEND16(req
->base
.questions
[i
]->dns_question_class
);
1766 /* Add answer, authority, and additional sections. */
1767 for (i
=0; i
<3; ++i
) {
1768 struct server_reply_item
*item
;
1772 item
= req
->authority
;
1774 item
= req
->additional
;
1776 r
= dnsname_to_labels(buf
, buf_len
, j
, item
->name
, strlen(item
->name
), &table
);
1781 APPEND16(item
->type
);
1782 APPEND16(item
->class);
1783 APPEND32(item
->ttl
);
1784 if (item
->is_name
) {
1785 off_t len_idx
= j
, name_start
;
1788 r
= dnsname_to_labels(buf
, buf_len
, j
, item
->data
, strlen(item
->data
), &table
);
1792 _t
= htons( (j
-name_start
) );
1793 memcpy(buf
+len_idx
, &_t
, 2);
1795 APPEND16(item
->datalen
);
1796 if (j
+item
->datalen
> (off_t
)buf_len
)
1798 memcpy(buf
+j
, item
->data
, item
->datalen
);
1808 buf
[2] |= 0x02; /* set the truncated bit. */
1811 req
->response_len
= (size_t)j
;
1813 if (!(req
->response
= mm_malloc(req
->response_len
))) {
1814 server_request_free_answers(req
);
1815 dnslabel_clear(&table
);
1818 memcpy(req
->response
, buf
, req
->response_len
);
1819 server_request_free_answers(req
);
1820 dnslabel_clear(&table
);
1824 /* exported function */
1826 evdns_server_request_respond(struct evdns_server_request
*_req
, int err
)
1828 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1829 struct evdns_server_port
*port
= req
->port
;
1831 if (!req
->response
) {
1832 if ((r
= evdns_server_request_format_response(req
, err
))<0)
1836 r
= sendto(port
->socket
, req
->response
, req
->response_len
, 0,
1837 (struct sockaddr
*) &req
->addr
, req
->addrlen
);
1839 int error
= last_error(port
->socket
);
1840 if (! error_is_eagain(error
))
1843 if (port
->pending_replies
) {
1844 req
->prev_pending
= port
->pending_replies
->prev_pending
;
1845 req
->next_pending
= port
->pending_replies
;
1846 req
->prev_pending
->next_pending
=
1847 req
->next_pending
->prev_pending
= req
;
1849 req
->prev_pending
= req
->next_pending
= req
;
1850 port
->pending_replies
= req
;
1853 (void) event_del(&port
->event
);
1854 CLEAR(&port
->event
);
1855 event_set(&port
->event
, port
->socket
, (port
->closing
?0:EV_READ
) | EV_WRITE
| EV_PERSIST
, server_port_ready_callback
, port
);
1857 if (event_add(&port
->event
, NULL
) < 0) {
1858 log(EVDNS_LOG_WARN
, "Error from libevent when adding event for DNS server");
1865 if (server_request_free(req
))
1868 if (port
->pending_replies
)
1869 server_port_flush(port
);
1874 /* Free all storage held by RRs in req. */
1876 server_request_free_answers(struct server_request
*req
)
1878 struct server_reply_item
*victim
, *next
, **list
;
1880 for (i
= 0; i
< 3; ++i
) {
1882 list
= &req
->answer
;
1884 list
= &req
->authority
;
1886 list
= &req
->additional
;
1890 next
= victim
->next
;
1891 mm_free(victim
->name
);
1893 mm_free(victim
->data
);
1901 /* Free all storage held by req, and remove links to it. */
1902 /* return true iff we just wound up freeing the server_port. */
1904 server_request_free(struct server_request
*req
)
1907 if (req
->base
.questions
) {
1908 for (i
= 0; i
< req
->base
.nquestions
; ++i
)
1909 mm_free(req
->base
.questions
[i
]);
1910 mm_free(req
->base
.questions
);
1914 if (req
->port
->pending_replies
== req
) {
1915 if (req
->next_pending
&& req
->next_pending
!= req
)
1916 req
->port
->pending_replies
= req
->next_pending
;
1918 req
->port
->pending_replies
= NULL
;
1920 rc
= --req
->port
->refcnt
;
1923 if (req
->response
) {
1924 mm_free(req
->response
);
1927 server_request_free_answers(req
);
1929 if (req
->next_pending
&& req
->next_pending
!= req
) {
1930 req
->next_pending
->prev_pending
= req
->prev_pending
;
1931 req
->prev_pending
->next_pending
= req
->next_pending
;
1935 server_port_free(req
->port
);
1945 /* Free all storage held by an evdns_server_port. Only called when the
1946 * reference count is down to 0. */
1948 server_port_free(struct evdns_server_port
*port
)
1951 assert(!port
->refcnt
);
1952 assert(!port
->pending_replies
);
1953 if (port
->socket
> 0) {
1954 CLOSE_SOCKET(port
->socket
);
1957 (void) event_del(&port
->event
);
1958 CLEAR(&port
->event
);
1963 /* exported function */
1965 evdns_server_request_drop(struct evdns_server_request
*_req
)
1967 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1968 server_request_free(req
);
1972 /* exported function */
1974 evdns_server_request_get_requesting_addr(struct evdns_server_request
*_req
, struct sockaddr
*sa
, int addr_len
)
1976 struct server_request
*req
= TO_SERVER_REQUEST(_req
);
1977 if (addr_len
< (int)req
->addrlen
)
1979 memcpy(sa
, &(req
->addr
), req
->addrlen
);
1980 return req
->addrlen
;
1986 /* this is a libevent callback function which is called when a request */
1987 /* has timed out. */
1989 evdns_request_timeout_callback(int fd
, short events
, void *arg
) {
1990 struct evdns_request
*const req
= (struct evdns_request
*) arg
;
1994 log(EVDNS_LOG_DEBUG
, "Request %lx timed out", (unsigned long) arg
);
1996 req
->ns
->timedout
++;
1997 if (req
->ns
->timedout
> global_max_nameserver_timeout
) {
1998 req
->ns
->timedout
= 0;
1999 nameserver_failed(req
->ns
, "request timed out.");
2002 if (req
->tx_count
>= global_max_retransmits
) {
2003 /* this request has failed */
2004 reply_callback(req
, 0, DNS_ERR_TIMEOUT
, NULL
);
2005 request_finished(req
, &req_head
);
2008 /* Stop waiting for the timeout. No need to do this in
2009 * request_finished; that one already deletes the timeout event.
2010 * XXXX023 port this change to libevent. */
2011 del_timeout_event(req
);
2012 evdns_request_transmit(req
);
2016 /* try to send a request to a given server. */
2020 /* 1 temporary failure */
2021 /* 2 other failure */
2023 evdns_request_transmit_to(struct evdns_request
*req
, struct nameserver
*server
) {
2024 const ssize_t r
= send(server
->socket
, (void*)req
->request
,
2025 req
->request_len
, 0);
2027 int err
= last_error(server
->socket
);
2028 if (error_is_eagain(err
)) return 1;
2029 nameserver_failed(req
->ns
, tor_socket_strerror(err
));
2031 } else if (r
!= (ssize_t
)req
->request_len
) {
2032 return 1; /* short write */
2038 /* try to send a request, updating the fields of the request */
2045 evdns_request_transmit(struct evdns_request
*req
) {
2048 /* if we fail to send this packet then this flag marks it */
2049 /* for evdns_transmit */
2050 req
->transmit_me
= 1;
2051 if (req
->trans_id
== 0xffff) abort();
2053 if (req
->ns
->choked
) {
2054 /* don't bother trying to write to a socket */
2055 /* which we have had EAGAIN from */
2059 r
= evdns_request_transmit_to(req
, req
->ns
);
2063 req
->ns
->choked
= 1;
2064 nameserver_write_waiting(req
->ns
, 1);
2067 /* failed to transmit the request entirely. */
2069 /* fall through: we'll set a timeout, which will time out,
2070 * and make us retransmit the request anyway. */
2072 /* transmitted; we need to check for timeout. */
2073 log(EVDNS_LOG_DEBUG
,
2074 "Setting timeout for request %lx", (unsigned long) req
);
2076 if (add_timeout_event(req
, &global_timeout
) < 0) {
2078 "Error from libevent when adding timer for request %lx",
2079 (unsigned long) req
);
2083 req
->transmit_me
= 0;
2089 nameserver_probe_callback(int result
, char type
, int count
, int ttl
, void *addresses
, void *arg
) {
2090 struct sockaddr
*addr
= arg
;
2091 struct nameserver
*server
;
2097 for (server
= server_head
; server
; server
= server
->next
) {
2098 if (sockaddr_eq(addr
, (struct sockaddr
*) &server
->address
, 1)) {
2099 if (result
== DNS_ERR_NONE
|| result
== DNS_ERR_NOTEXIST
) {
2100 /* this is a good reply */
2101 nameserver_up(server
);
2103 nameserver_probe_failed(server
);
2106 if (server
->next
== server_head
)
2114 nameserver_send_probe(struct nameserver
*const ns
) {
2115 struct evdns_request
*req
;
2116 struct sockaddr_storage
*addr
;
2117 /* here we need to send a probe to a given nameserver */
2118 /* in the hope that it is up now. */
2120 /* We identify the nameserver by its address, in case it is removed before
2121 * our probe comes back. */
2122 addr
= mm_malloc(sizeof(struct sockaddr_storage
));
2123 memcpy(addr
, &ns
->address
, sizeof(struct sockaddr_storage
));
2125 log(EVDNS_LOG_DEBUG
, "Sending probe to %s", debug_ntop((struct sockaddr
*)&ns
->address
));
2127 req
= request_new(TYPE_A
, "www.google.com", DNS_QUERY_NO_SEARCH
, nameserver_probe_callback
, addr
);
2132 /* we force this into the inflight queue no matter what */
2133 request_trans_id_set(req
, transaction_id_pick());
2135 request_submit(req
);
2139 /* 0 didn't try to transmit anything */
2140 /* 1 tried to transmit something */
2142 evdns_transmit(void) {
2143 char did_try_to_transmit
= 0;
2146 struct evdns_request
*const started_at
= req_head
, *req
= req_head
;
2147 /* first transmit all the requests which are currently waiting */
2149 if (req
->transmit_me
) {
2150 did_try_to_transmit
= 1;
2151 evdns_request_transmit(req
);
2155 } while (req
!= started_at
);
2158 return did_try_to_transmit
;
2161 /* exported function */
2163 evdns_count_nameservers(void)
2165 const struct nameserver
*server
= server_head
;
2171 server
= server
->next
;
2172 } while (server
!= server_head
);
2176 /* exported function */
2178 evdns_clear_nameservers_and_suspend(void)
2180 struct nameserver
*server
= server_head
, *started_at
= server_head
;
2181 struct evdns_request
*req
= req_head
, *req_started_at
= req_head
;
2186 struct nameserver
*next
= server
->next
;
2187 (void) event_del(&server
->event
);
2188 CLEAR(&server
->event
);
2189 del_timeout_event(server
);
2190 if (server
->socket
>= 0)
2191 CLOSE_SOCKET(server
->socket
);
2194 if (next
== started_at
)
2199 global_good_nameservers
= 0;
2202 struct evdns_request
*next
= req
->next
;
2203 req
->tx_count
= req
->reissue_count
= 0;
2205 /* ???? What to do about searches? */
2206 del_timeout_event(req
);
2208 req
->transmit_me
= 0;
2210 global_requests_waiting
++;
2211 evdns_request_insert(req
, &req_waiting_head
);
2212 /* We want to insert these suspended elements at the front of
2213 * the waiting queue, since they were pending before any of
2214 * the waiting entries were added. This is a circular list,
2215 * so we can just shift the start back by one.*/
2216 req_waiting_head
= req_waiting_head
->prev
;
2218 if (next
== req_started_at
)
2223 global_requests_inflight
= 0;
2228 static struct sockaddr_storage global_bind_address
;
2229 static socklen_t global_bind_addrlen
= 0;
2230 static int global_bind_addr_is_set
= 0;
2232 evdns_set_default_outgoing_bind_address(const struct sockaddr
*addr
,
2235 memset(&global_bind_address
, 0, sizeof(global_bind_address
));
2237 assert(addrlen
<= (socklen_t
)sizeof(global_bind_address
));
2238 memcpy(&global_bind_address
, addr
, addrlen
);
2239 global_bind_addrlen
= addrlen
;
2240 global_bind_addr_is_set
= 1;
2242 global_bind_addr_is_set
= 0;
2246 /* exported function */
2250 evdns_requests_pump_waiting_queue();
2255 sockaddr_is_loopback(const struct sockaddr
*addr
)
2257 static const char LOOPBACK_S6
[16] =
2258 "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1";
2259 if (addr
->sa_family
== AF_INET
) {
2260 struct sockaddr_in
*sin
= (struct sockaddr_in
*)addr
;
2261 return (ntohl(sin
->sin_addr
.s_addr
) & 0xff000000) == 0x7f000000;
2262 } else if (addr
->sa_family
== AF_INET6
) {
2263 struct sockaddr_in6
*sin6
= (struct sockaddr_in6
*)addr
;
2264 return fast_memeq(sin6
->sin6_addr
.s6_addr
, LOOPBACK_S6
, 16);
2270 _evdns_nameserver_add_impl(const struct sockaddr
*address
,
2271 socklen_t addrlen
) {
2272 /* first check to see if we already have this nameserver */
2274 const struct nameserver
*server
= server_head
, *const started_at
= server_head
;
2275 struct nameserver
*ns
;
2280 if (sockaddr_eq(address
, (struct sockaddr
*)&server
->address
, 1)) {
2281 log(EVDNS_LOG_DEBUG
, "Duplicate nameserver.");
2284 server
= server
->next
;
2285 } while (server
!= started_at
);
2287 if (addrlen
> (int)sizeof(ns
->address
)) {
2288 log(EVDNS_LOG_DEBUG
, "Addrlen %d too long.", (int)addrlen
);
2292 ns
= (struct nameserver
*) mm_malloc(sizeof(struct nameserver
));
2295 memset(ns
, 0, sizeof(struct nameserver
));
2297 evtimer_set(&ns
->timeout_event
, nameserver_prod_callback
, ns
);
2299 ns
->socket
= tor_open_socket(address
->sa_family
, SOCK_DGRAM
, 0);
2300 if (ns
->socket
< 0) { err
= 1; goto out1
; }
2303 u_long nonblocking
= 1;
2304 ioctlsocket(ns
->socket
, FIONBIO
, &nonblocking
);
2307 fcntl(ns
->socket
, F_SETFL
, O_NONBLOCK
);
2310 if (global_bind_addr_is_set
&&
2311 !sockaddr_is_loopback((struct sockaddr
*)&global_bind_address
)) {
2312 if (bind(ns
->socket
, (struct sockaddr
*)&global_bind_address
,
2313 global_bind_addrlen
) < 0) {
2314 log(EVDNS_LOG_DEBUG
, "Couldn't bind to outgoing address.");
2320 if (connect(ns
->socket
, address
, addrlen
) != 0) {
2321 log(EVDNS_LOG_DEBUG
, "Couldn't open socket to nameserver.");
2326 memcpy(&ns
->address
, address
, addrlen
);
2328 event_set(&ns
->event
, ns
->socket
, EV_READ
| EV_PERSIST
, nameserver_ready_callback
, ns
);
2329 if (event_add(&ns
->event
, NULL
) < 0) {
2330 log(EVDNS_LOG_DEBUG
, "Couldn't add event for nameserver.");
2335 log(EVDNS_LOG_DEBUG
, "Added nameserver %s", debug_ntop(address
));
2337 /* insert this nameserver into the list of them */
2339 ns
->next
= ns
->prev
= ns
;
2342 ns
->next
= server_head
->next
;
2343 ns
->prev
= server_head
;
2344 server_head
->next
= ns
;
2345 if (server_head
->prev
== server_head
) {
2346 server_head
->prev
= ns
;
2350 global_good_nameservers
++;
2355 CLOSE_SOCKET(ns
->socket
);
2359 log(EVDNS_LOG_WARN
, "Unable to add nameserver %s: error %d", debug_ntop(address
), err
);
2363 /* exported function */
2365 evdns_nameserver_add(uint32_t address
) {
2366 struct sockaddr_in sin
;
2367 memset(&sin
, 0, sizeof(sin
));
2368 sin
.sin_family
= AF_INET
;
2369 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
2370 sin
.sin_len
= sizeof(sin
);
2372 sin
.sin_addr
.s_addr
= htonl(address
);
2374 return _evdns_nameserver_add_impl((struct sockaddr
*) &sin
, sizeof(sin
));
2377 /* exported function */
2379 evdns_nameserver_ip_add(const char *ip_as_string
) {
2382 const char *cp
, *addr_part
, *port_part
;
2384 /* recognized formats are:
2392 log(EVDNS_LOG_DEBUG
, "Trying to add nameserver <%s>", ip_as_string
);
2394 cp
= strchr(ip_as_string
, ':');
2395 if (*ip_as_string
== '[') {
2397 if (!(cp
= strchr(ip_as_string
, ']'))) {
2398 log(EVDNS_LOG_DEBUG
, "Nameserver missing closing ]");
2401 len
= cp
-(ip_as_string
+ 1);
2402 if (len
> sizeof(buf
)-1) {
2403 log(EVDNS_LOG_DEBUG
, "[Nameserver] does not fit in buffer.");
2406 memcpy(buf
, ip_as_string
+1, len
);
2414 } else if (cp
&& strchr(cp
+1, ':')) {
2416 addr_part
= ip_as_string
;
2420 if (cp
- ip_as_string
> (int)sizeof(buf
)-1) {
2421 log(EVDNS_LOG_DEBUG
, "Nameserver does not fit in buffer.");
2424 memcpy(buf
, ip_as_string
, cp
-ip_as_string
);
2425 buf
[cp
-ip_as_string
] = '\0';
2429 addr_part
= ip_as_string
;
2434 if (port_part
== NULL
) {
2437 port
= strtoint(port_part
);
2438 if (port
<= 0 || port
> 65535) {
2439 log(EVDNS_LOG_DEBUG
, "Nameserver port <%s> out of range",
2445 /* Tor-only. needs a more general fix. */
2448 struct sockaddr_in6 sin6
;
2449 memset(&sin6
, 0, sizeof(sin6
));
2450 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN
2451 sin6
.sin6_len
= sizeof(sin6
);
2453 sin6
.sin6_family
= AF_INET6
;
2454 sin6
.sin6_port
= htons(port
);
2455 if (1 != tor_inet_pton(AF_INET6
, addr_part
, &sin6
.sin6_addr
)) {
2456 log(EVDNS_LOG_DEBUG
, "inet_pton(%s) failed", addr_part
);
2459 return _evdns_nameserver_add_impl((struct sockaddr
*)&sin6
,
2462 struct sockaddr_in sin
;
2463 memset(&sin
, 0, sizeof(sin
));
2464 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
2465 sin
.sin_len
= sizeof(sin
);
2467 sin
.sin_family
= AF_INET
;
2468 sin
.sin_port
= htons(port
);
2469 if (!inet_aton(addr_part
, &sin
.sin_addr
)) {
2470 log(EVDNS_LOG_DEBUG
, "inet_pton(%s) failed", addr_part
);
2473 return _evdns_nameserver_add_impl((struct sockaddr
*)&sin
,
2479 evdns_nameserver_sockaddr_add(const struct sockaddr
*sa
, socklen_t len
)
2481 return _evdns_nameserver_add_impl(sa
, len
);
2484 /* insert into the tail of the queue */
2486 evdns_request_insert(struct evdns_request
*req
, struct evdns_request
**head
) {
2489 req
->next
= req
->prev
= req
;
2493 req
->prev
= (*head
)->prev
;
2494 req
->prev
->next
= req
;
2496 (*head
)->prev
= req
;
2500 string_num_dots(const char *s
) {
2502 while ((s
= strchr(s
, '.'))) {
2509 static struct evdns_request
*
2510 request_new(int type
, const char *name
, int flags
,
2511 evdns_callback_type callback
, void *user_ptr
) {
2512 const char issuing_now
=
2513 (global_requests_inflight
< global_max_requests_inflight
) ? 1 : 0;
2515 const size_t name_len
= strlen(name
);
2516 const size_t request_max_len
= evdns_request_len(name_len
);
2517 const u16 trans_id
= issuing_now
? transaction_id_pick() : 0xffff;
2518 /* the request data is alloced in a single block with the header */
2519 struct evdns_request
*const req
=
2520 (struct evdns_request
*) mm_malloc(sizeof(struct evdns_request
) + request_max_len
);
2525 if (!req
) return NULL
;
2527 if (name_len
>= sizeof(namebuf
)) {
2532 memset(req
, 0, sizeof(struct evdns_request
));
2534 evtimer_set(&req
->timeout_event
, evdns_request_timeout_callback
, req
);
2536 if (global_randomize_case
) {
2539 strlcpy(namebuf
, name
, sizeof(namebuf
));
2540 rand_bytes_function(randbits
, (name_len
+7)/8);
2541 for (i
= 0; i
< name_len
; ++i
) {
2542 if (ISALPHA(namebuf
[i
])) {
2543 if ((randbits
[i
>> 3] & (1<<(i
%7))))
2544 namebuf
[i
] = TOLOWER(namebuf
[i
]);
2546 namebuf
[i
] = TOUPPER(namebuf
[i
]);
2552 /* request data lives just after the header */
2553 req
->request
= ((u8
*) req
) + sizeof(struct evdns_request
);
2554 /* denotes that the request data shouldn't be mm_free()ed */
2555 req
->request_appended
= 1;
2556 rlen
= evdns_request_data_build(name
, name_len
, trans_id
,
2557 type
, CLASS_INET
, req
->request
, request_max_len
);
2560 req
->request_len
= rlen
;
2561 req
->trans_id
= trans_id
;
2563 req
->request_type
= type
;
2564 req
->user_pointer
= user_ptr
;
2565 req
->user_callback
= callback
;
2566 req
->ns
= issuing_now
? nameserver_pick() : NULL
;
2567 req
->next
= req
->prev
= NULL
;
2577 request_submit(struct evdns_request
*const req
) {
2579 /* if it has a nameserver assigned then this is going */
2580 /* straight into the inflight queue */
2581 evdns_request_insert(req
, &req_head
);
2582 global_requests_inflight
++;
2583 evdns_request_transmit(req
);
2585 evdns_request_insert(req
, &req_waiting_head
);
2586 global_requests_waiting
++;
2590 /* exported function */
2591 int evdns_resolve_ipv4(const char *name
, int flags
,
2592 evdns_callback_type callback
, void *ptr
) {
2593 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s", name
);
2594 if (flags
& DNS_QUERY_NO_SEARCH
) {
2595 struct evdns_request
*const req
=
2596 request_new(TYPE_A
, name
, flags
, callback
, ptr
);
2599 request_submit(req
);
2602 return (search_request_new(TYPE_A
, name
, flags
, callback
, ptr
));
2606 /* exported function */
2607 int evdns_resolve_ipv6(const char *name
, int flags
,
2608 evdns_callback_type callback
, void *ptr
) {
2609 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s", name
);
2610 if (flags
& DNS_QUERY_NO_SEARCH
) {
2611 struct evdns_request
*const req
=
2612 request_new(TYPE_AAAA
, name
, flags
, callback
, ptr
);
2615 request_submit(req
);
2618 return (search_request_new(TYPE_AAAA
, name
, flags
, callback
, ptr
));
2622 int evdns_resolve_reverse(const struct in_addr
*in
, int flags
, evdns_callback_type callback
, void *ptr
) {
2624 struct evdns_request
*req
;
2627 a
= ntohl(in
->s_addr
);
2628 snprintf(buf
, sizeof(buf
), "%d.%d.%d.%d.in-addr.arpa",
2629 (int)(u8
)((a
)&0xff),
2630 (int)(u8
)((a
>>8 )&0xff),
2631 (int)(u8
)((a
>>16)&0xff),
2632 (int)(u8
)((a
>>24)&0xff));
2633 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s (reverse)", buf
);
2634 req
= request_new(TYPE_PTR
, buf
, flags
, callback
, ptr
);
2636 request_submit(req
);
2640 int evdns_resolve_reverse_ipv6(const struct in6_addr
*in
, int flags
, evdns_callback_type callback
, void *ptr
) {
2641 /* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
2644 struct evdns_request
*req
;
2648 for (i
=15; i
>= 0; --i
) {
2649 u8 byte
= in
->s6_addr
[i
];
2650 *cp
++ = "0123456789abcdef"[byte
& 0x0f];
2652 *cp
++ = "0123456789abcdef"[byte
>> 4];
2655 assert(cp
+ strlen("ip6.arpa") < buf
+sizeof(buf
));
2656 memcpy(cp
, "ip6.arpa", strlen("ip6.arpa")+1);
2657 log(EVDNS_LOG_DEBUG
, "Resolve requested for %s (reverse)", buf
);
2658 req
= request_new(TYPE_PTR
, buf
, flags
, callback
, ptr
);
2660 request_submit(req
);
2664 /*/////////////////////////////////////////////////////////////////// */
2665 /* Search support */
2667 /* the libc resolver has support for searching a number of domains */
2668 /* to find a name. If nothing else then it takes the single domain */
2669 /* from the gethostname() call. */
2671 /* It can also be configured via the domain and search options in a */
2674 /* The ndots option controls how many dots it takes for the resolver */
2675 /* to decide that a name is non-local and so try a raw lookup first. */
2677 struct search_domain
{
2679 struct search_domain
*next
;
2680 /* the text string is appended to this structure */
2683 struct search_state
{
2687 struct search_domain
*head
;
2690 static struct search_state
*global_search_state
= NULL
;
2693 search_state_decref(struct search_state
*const state
) {
2696 if (!state
->refcount
) {
2697 struct search_domain
*next
, *dom
;
2698 for (dom
= state
->head
; dom
; dom
= next
) {
2708 static struct search_state
*
2709 search_state_new(void) {
2710 struct search_state
*state
= (struct search_state
*) mm_malloc(sizeof(struct search_state
));
2711 if (!state
) return NULL
;
2712 memset(state
, 0, sizeof(struct search_state
));
2713 state
->refcount
= 1;
2720 search_postfix_clear(void) {
2721 search_state_decref(global_search_state
);
2723 global_search_state
= search_state_new();
2726 /* exported function */
2728 evdns_search_clear(void) {
2729 search_postfix_clear();
2733 search_postfix_add(const char *domain
) {
2735 struct search_domain
*sdomain
;
2736 while (domain
[0] == '.') domain
++;
2737 domain_len
= strlen(domain
);
2739 if (!global_search_state
) global_search_state
= search_state_new();
2740 if (!global_search_state
) return;
2741 global_search_state
->num_domains
++;
2743 sdomain
= (struct search_domain
*) mm_malloc(sizeof(struct search_domain
) + domain_len
);
2744 if (!sdomain
) return;
2745 memcpy( ((u8
*) sdomain
) + sizeof(struct search_domain
), domain
, domain_len
);
2746 sdomain
->next
= global_search_state
->head
;
2747 sdomain
->len
= domain_len
;
2749 global_search_state
->head
= sdomain
;
2752 /* reverse the order of members in the postfix list. This is needed because, */
2753 /* when parsing resolv.conf we push elements in the wrong order */
2755 search_reverse(void) {
2756 struct search_domain
*cur
, *prev
= NULL
, *next
;
2757 cur
= global_search_state
->head
;
2765 global_search_state
->head
= prev
;
2768 /* exported function */
2770 evdns_search_add(const char *domain
) {
2771 search_postfix_add(domain
);
2774 /* exported function */
2776 evdns_search_ndots_set(const int ndots
) {
2777 if (!global_search_state
) global_search_state
= search_state_new();
2778 if (!global_search_state
) return;
2779 global_search_state
->ndots
= ndots
;
2783 search_set_from_hostname(void) {
2784 char hostname
[HOST_NAME_MAX
+ 1], *domainname
;
2786 search_postfix_clear();
2787 if (gethostname(hostname
, sizeof(hostname
))) return;
2788 domainname
= strchr(hostname
, '.');
2789 if (!domainname
) return;
2790 search_postfix_add(domainname
);
2793 /* warning: returns malloced string */
2795 search_make_new(const struct search_state
*const state
, int n
, const char *const base_name
) {
2796 const size_t base_len
= strlen(base_name
);
2797 const char need_to_append_dot
= base_name
[base_len
- 1] == '.' ? 0 : 1;
2798 struct search_domain
*dom
;
2800 for (dom
= state
->head
; dom
; dom
= dom
->next
) {
2802 /* this is the postfix we want */
2803 /* the actual postfix string is kept at the end of the structure */
2804 const u8
*const postfix
= ((u8
*) dom
) + sizeof(struct search_domain
);
2805 const size_t postfix_len
= dom
->len
;
2806 char *const newname
= (char *) mm_malloc(base_len
+ need_to_append_dot
+ postfix_len
+ 1);
2807 if (!newname
) return NULL
;
2808 memcpy(newname
, base_name
, base_len
);
2809 if (need_to_append_dot
) newname
[base_len
] = '.';
2810 memcpy(newname
+ base_len
+ need_to_append_dot
, postfix
, postfix_len
);
2811 newname
[base_len
+ need_to_append_dot
+ postfix_len
] = 0;
2816 /* we ran off the end of the list and still didn't find the requested string */
2818 return NULL
; /* unreachable; stops warnings in some compilers. */
2822 search_request_new(int type
, const char *const name
, int flags
, evdns_callback_type user_callback
, void *user_arg
) {
2823 assert(type
== TYPE_A
|| type
== TYPE_AAAA
);
2824 if ( ((flags
& DNS_QUERY_NO_SEARCH
) == 0) &&
2825 global_search_state
&&
2826 global_search_state
->num_domains
) {
2827 /* we have some domains to search */
2828 struct evdns_request
*req
;
2829 if (string_num_dots(name
) >= global_search_state
->ndots
) {
2830 req
= request_new(type
, name
, flags
, user_callback
, user_arg
);
2832 req
->search_index
= -1;
2834 char *const new_name
= search_make_new(global_search_state
, 0, name
);
2835 if (!new_name
) return 1;
2836 req
= request_new(type
, new_name
, flags
, user_callback
, user_arg
);
2839 req
->search_index
= 0;
2841 req
->search_origname
= mm_strdup(name
);
2842 req
->search_state
= global_search_state
;
2843 req
->search_flags
= flags
;
2844 global_search_state
->refcount
++;
2845 request_submit(req
);
2848 struct evdns_request
*const req
= request_new(type
, name
, flags
, user_callback
, user_arg
);
2850 request_submit(req
);
2855 /* this is called when a request has failed to find a name. We need to check */
2856 /* if it is part of a search and, if so, try the next name in the list */
2858 /* 0 another request has been submitted */
2859 /* 1 no more requests needed */
2861 search_try_next(struct evdns_request
*const req
) {
2862 if (req
->search_state
) {
2863 /* it is part of a search */
2865 struct evdns_request
*newreq
;
2866 req
->search_index
++;
2867 if (req
->search_index
>= req
->search_state
->num_domains
) {
2868 /* no more postfixes to try, however we may need to try */
2869 /* this name without a postfix */
2870 if (string_num_dots(req
->search_origname
) < req
->search_state
->ndots
) {
2871 /* yep, we need to try it raw */
2872 struct evdns_request
*const newreq
= request_new(req
->request_type
, req
->search_origname
, req
->search_flags
, req
->user_callback
, req
->user_pointer
);
2873 log(EVDNS_LOG_DEBUG
, "Search: trying raw query %s", req
->search_origname
);
2875 request_submit(newreq
);
2882 new_name
= search_make_new(req
->search_state
, req
->search_index
, req
->search_origname
);
2883 if (!new_name
) return 1;
2884 log(EVDNS_LOG_DEBUG
, "Search: now trying %s (%d)", new_name
, req
->search_index
);
2885 newreq
= request_new(req
->request_type
, new_name
, req
->search_flags
, req
->user_callback
, req
->user_pointer
);
2887 if (!newreq
) return 1;
2888 newreq
->search_origname
= req
->search_origname
;
2889 req
->search_origname
= NULL
;
2890 newreq
->search_state
= req
->search_state
;
2891 newreq
->search_flags
= req
->search_flags
;
2892 newreq
->search_index
= req
->search_index
;
2893 newreq
->search_state
->refcount
++;
2894 request_submit(newreq
);
2901 search_request_finished(struct evdns_request
*const req
) {
2902 if (req
->search_state
) {
2903 search_state_decref(req
->search_state
);
2904 req
->search_state
= NULL
;
2906 if (req
->search_origname
) {
2907 mm_free(req
->search_origname
);
2908 req
->search_origname
= NULL
;
2912 /*/////////////////////////////////////////////////////////////////// */
2913 /* Parsing resolv.conf files */
2916 evdns_resolv_set_defaults(int flags
) {
2917 /* if the file isn't found then we assume a local resolver */
2918 if (flags
& DNS_OPTION_SEARCH
) search_set_from_hostname();
2919 if (flags
& DNS_OPTION_NAMESERVERS
) evdns_nameserver_ip_add("127.0.0.1");
2922 /* helper version of atoi which returns -1 on error */
2924 strtoint(const char *const str
) {
2926 const long r
= strtol(str
, &endptr
, 10);
2927 if (*endptr
|| r
> INT_MAX
) return -1;
2931 /* helper version of atoi that returns -1 on error and clips to bounds. */
2933 strtoint_clipped(const char *const str
, int min
, int max
)
2935 int r
= strtoint(str
);
2946 /* exported function */
2948 evdns_set_option(const char *option
, const char *val
, int flags
)
2950 if (!strncmp(option
, "ndots:", 6)) {
2951 const int ndots
= strtoint(val
);
2952 if (ndots
== -1) return -1;
2953 if (!(flags
& DNS_OPTION_SEARCH
)) return 0;
2954 log(EVDNS_LOG_DEBUG
, "Setting ndots to %d", ndots
);
2955 if (!global_search_state
) global_search_state
= search_state_new();
2956 if (!global_search_state
) return -1;
2957 global_search_state
->ndots
= ndots
;
2958 } else if (!strncmp(option
, "timeout:", 8)) {
2959 const int timeout
= strtoint(val
);
2960 if (timeout
== -1) return -1;
2961 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2962 log(EVDNS_LOG_DEBUG
, "Setting timeout to %d", timeout
);
2963 global_timeout
.tv_sec
= timeout
;
2964 } else if (!strncmp(option
, "max-timeouts:", 12)) {
2965 const int maxtimeout
= strtoint_clipped(val
, 1, 255);
2966 if (maxtimeout
== -1) return -1;
2967 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2968 log(EVDNS_LOG_DEBUG
, "Setting maximum allowed timeouts to %d",
2970 global_max_nameserver_timeout
= maxtimeout
;
2971 } else if (!strncmp(option
, "max-inflight:", 13)) {
2972 const int maxinflight
= strtoint_clipped(val
, 1, 65000);
2973 if (maxinflight
== -1) return -1;
2974 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2975 log(EVDNS_LOG_DEBUG
, "Setting maximum inflight requests to %d",
2977 global_max_requests_inflight
= maxinflight
;
2978 } else if (!strncmp(option
, "attempts:", 9)) {
2979 int retries
= strtoint(val
);
2980 if (retries
== -1) return -1;
2981 if (retries
> 255) retries
= 255;
2982 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2983 log(EVDNS_LOG_DEBUG
, "Setting retries to %d", retries
);
2984 global_max_retransmits
= retries
;
2985 } else if (!strncmp(option
, "randomize-case:", 15)) {
2986 int randcase
= strtoint(val
);
2987 if (!(flags
& DNS_OPTION_MISC
)) return 0;
2988 log(EVDNS_LOG_DEBUG
, "Setting randomize_case to %d", randcase
);
2989 global_randomize_case
= randcase
;
2995 resolv_conf_parse_line(char *const start
, int flags
) {
2997 static const char *const delims
= " \t";
2998 #define NEXT_TOKEN tor_strtok_r(NULL, delims, &strtok_state)
3000 char *const first_token
= tor_strtok_r(start
, delims
, &strtok_state
);
3001 if (!first_token
) return;
3003 if (!strcmp(first_token
, "nameserver") && (flags
& DNS_OPTION_NAMESERVERS
)) {
3004 const char *const nameserver
= NEXT_TOKEN
;
3005 evdns_nameserver_ip_add(nameserver
);
3006 } else if (!strcmp(first_token
, "domain") && (flags
& DNS_OPTION_SEARCH
)) {
3007 const char *const domain
= NEXT_TOKEN
;
3009 search_postfix_clear();
3010 search_postfix_add(domain
);
3012 } else if (!strcmp(first_token
, "search") && (flags
& DNS_OPTION_SEARCH
)) {
3014 search_postfix_clear();
3016 while ((domain
= NEXT_TOKEN
)) {
3017 search_postfix_add(domain
);
3020 } else if (!strcmp(first_token
, "options")) {
3022 while ((option
= NEXT_TOKEN
)) {
3023 const char *val
= strchr(option
, ':');
3024 evdns_set_option(option
, val
? val
+1 : "", flags
);
3030 /* exported function */
3033 /* 1 failed to open file */
3034 /* 2 failed to stat file */
3035 /* 3 file too large */
3036 /* 4 out of memory */
3037 /* 5 short read from file */
3039 evdns_resolv_conf_parse(int flags
, const char *const filename
) {
3046 log(EVDNS_LOG_DEBUG
, "Parsing resolv.conf file %s", filename
);
3048 fd
= tor_open_cloexec(filename
, O_RDONLY
, 0);
3050 evdns_resolv_set_defaults(flags
);
3054 if (fstat(fd
, &st
)) { err
= 2; goto out1
; }
3056 evdns_resolv_set_defaults(flags
);
3057 err
= (flags
& DNS_OPTION_NAMESERVERS
) ? 6 : 0;
3060 if (st
.st_size
> 65535) { err
= 3; goto out1
; } /* no resolv.conf should be any bigger */
3062 resolv
= (u8
*) mm_malloc((size_t)st
.st_size
+ 1);
3063 if (!resolv
) { err
= 4; goto out1
; }
3066 while ((r
= (int)read(fd
, resolv
+n
, (size_t)st
.st_size
-n
)) > 0) {
3068 if (n
== st
.st_size
)
3070 assert(n
< st
.st_size
);
3072 if (r
< 0) { err
= 5; goto out2
; }
3073 resolv
[n
] = 0; /* we malloced an extra byte; this should be fine. */
3075 start
= (char *) resolv
;
3077 char *const newline
= strchr(start
, '\n');
3079 resolv_conf_parse_line(start
, flags
);
3083 resolv_conf_parse_line(start
, flags
);
3084 start
= newline
+ 1;
3088 if (!server_head
&& (flags
& DNS_OPTION_NAMESERVERS
)) {
3089 /* no nameservers were configured. */
3090 evdns_nameserver_ip_add("127.0.0.1");
3093 if (flags
& DNS_OPTION_SEARCH
&& (!global_search_state
|| global_search_state
->num_domains
== 0)) {
3094 search_set_from_hostname();
3105 /* Add multiple nameservers from a space-or-comma-separated list. */
3107 evdns_nameserver_ip_add_line(const char *ips
) {
3112 while (ISSPACE(*ips
) || *ips
== ',' || *ips
== '\t')
3115 while (ISDIGIT(*ips
) || *ips
== '.' || *ips
== ':' || *ips
== '[' || *ips
== ']')
3117 buf
= mm_malloc(ips
-addr
+1);
3119 memcpy(buf
, addr
, ips
-addr
);
3120 buf
[ips
-addr
] = '\0';
3121 r
= evdns_nameserver_ip_add(buf
);
3128 typedef DWORD(WINAPI
*GetNetworkParams_fn_t
)(FIXED_INFO
*, DWORD
*);
3130 /* Use the windows GetNetworkParams interface in iphlpapi.dll to */
3131 /* figure out what our nameservers are. */
3133 load_nameservers_with_getnetworkparams(void)
3135 /* Based on MSDN examples and inspection of c-ares code. */
3138 ULONG size
= sizeof(FIXED_INFO
);
3140 int status
= 0, r
, added_any
;
3142 GetNetworkParams_fn_t fn
;
3144 if (!(handle
= load_windows_system_library(TEXT("iphlpapi.dll")))) {
3145 log(EVDNS_LOG_WARN
, "Could not open iphlpapi.dll");
3146 /* right now status = 0, doesn't that mean "good" - mikec */
3150 if (!(fn
= (GetNetworkParams_fn_t
) GetProcAddress(handle
, TEXT("GetNetworkParams")))) {
3151 log(EVDNS_LOG_WARN
, "Could not get address of function.");
3157 buf
= mm_malloc(size
);
3158 if (!buf
) { status
= 4; goto done
; }
3160 r
= fn(fixed
, &size
);
3161 if (r
!= ERROR_SUCCESS
&& r
!= ERROR_BUFFER_OVERFLOW
) {
3165 if (r
!= ERROR_SUCCESS
) {
3167 buf
= mm_malloc(size
);
3168 if (!buf
) { status
= 4; goto done
; }
3170 r
= fn(fixed
, &size
);
3171 if (r
!= ERROR_SUCCESS
) {
3172 log(EVDNS_LOG_DEBUG
, "fn() failed.");
3180 ns
= &(fixed
->DnsServerList
);
3182 r
= evdns_nameserver_ip_add_line(ns
->IpAddress
.String
);
3184 log(EVDNS_LOG_DEBUG
,"Could not add nameserver %s to list, "
3185 "error: %d; status: %d",
3186 (ns
->IpAddress
.String
),(int)GetLastError(), r
);
3189 log(EVDNS_LOG_DEBUG
,"Successfully added %s as nameserver",ns
->IpAddress
.String
);
3197 log(EVDNS_LOG_DEBUG
, "No nameservers added.");
3208 FreeLibrary(handle
);
3213 config_nameserver_from_reg_key(HKEY key
, const TCHAR
*subkey
)
3216 char ansibuf
[MAX_PATH
] = {0};
3217 DWORD bufsz
= 0, type
= 0;
3220 if (RegQueryValueEx(key
, subkey
, 0, &type
, NULL
, &bufsz
)
3223 if (!(buf
= mm_malloc(bufsz
)))
3226 if (RegQueryValueEx(key
, subkey
, 0, &type
, (LPBYTE
)buf
, &bufsz
)
3227 == ERROR_SUCCESS
&& bufsz
> 1) {
3228 wcstombs(ansibuf
,(wchar_t*)buf
,MAX_PATH
);/*XXXX UNICODE */
3229 abuf
[MAX_PATH
-1] = '\0';
3230 status
= evdns_nameserver_ip_add_line(ansibuf
);
3237 #define SERVICES_KEY TEXT("System\\CurrentControlSet\\Services\\")
3238 #define WIN_NS_9X_KEY SERVICES_KEY TEXT("VxD\\MSTCP")
3239 #define WIN_NS_NT_KEY SERVICES_KEY TEXT("Tcpip\\Parameters")
3242 load_nameservers_from_registry(void)
3247 memset(&info
, 0, sizeof(info
));
3248 info
.dwOSVersionInfoSize
= sizeof (info
);
3249 GetVersionEx(&info
);
3251 #define TRY(k, name) \
3252 if (!found && config_nameserver_from_reg_key(k,TEXT(name)) == 0) { \
3253 log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \
3255 } else if (!found) { \
3256 log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \
3260 if (info
.dwMajorVersion
>= 5) { /* NT */
3261 HKEY nt_key
= 0, interfaces_key
= 0;
3263 if (RegOpenKeyEx(HKEY_LOCAL_MACHINE
, WIN_NS_NT_KEY
, 0,
3264 KEY_READ
, &nt_key
) != ERROR_SUCCESS
) {
3265 log(EVDNS_LOG_DEBUG
,"Couldn't open nt key, %d",(int)GetLastError());
3268 r
= RegOpenKeyEx(nt_key
, TEXT("Interfaces"), 0,
3269 KEY_QUERY_VALUE
|KEY_ENUMERATE_SUB_KEYS
,
3271 if (r
!= ERROR_SUCCESS
) {
3272 log(EVDNS_LOG_DEBUG
,"Couldn't open interfaces key, %d",(int)GetLastError());
3275 TRY(nt_key
, "NameServer");
3276 TRY(nt_key
, "DhcpNameServer");
3277 TRY(interfaces_key
, "NameServer");
3278 TRY(interfaces_key
, "DhcpNameServer");
3279 RegCloseKey(interfaces_key
);
3280 RegCloseKey(nt_key
);
3283 if (RegOpenKeyEx(HKEY_LOCAL_MACHINE
, WIN_NS_9X_KEY
, 0,
3284 KEY_READ
, &win_key
) != ERROR_SUCCESS
) {
3285 log(EVDNS_LOG_DEBUG
, "Couldn't open registry key, %d", (int)GetLastError());
3288 TRY(win_key
, "NameServer");
3289 RegCloseKey(win_key
);
3293 log(EVDNS_LOG_WARN
,"Didn't find any nameservers.");
3296 return found
? 0 : -1;
3301 evdns_config_windows_nameservers(void)
3303 if (load_nameservers_with_getnetworkparams() == 0)
3305 return load_nameservers_from_registry();
3314 evdns_config_windows_nameservers();
3316 res
= evdns_resolv_conf_parse(DNS_OPTIONS_ALL
, "/etc/resolv.conf");
3323 evdns_err_to_string(int err
)
3326 case DNS_ERR_NONE
: return "no error";
3327 case DNS_ERR_FORMAT
: return "misformatted query";
3328 case DNS_ERR_SERVERFAILED
: return "server failed";
3329 case DNS_ERR_NOTEXIST
: return "name does not exist";
3330 case DNS_ERR_NOTIMPL
: return "query not implemented";
3331 case DNS_ERR_REFUSED
: return "refused";
3333 case DNS_ERR_TRUNCATED
: return "reply truncated or ill-formed";
3334 case DNS_ERR_UNKNOWN
: return "unknown";
3335 case DNS_ERR_TIMEOUT
: return "request timed out";
3336 case DNS_ERR_SHUTDOWN
: return "dns subsystem shut down";
3337 default: return "[Unknown error code]";
3342 evdns_shutdown(int fail_requests
)
3344 struct nameserver
*server
, *server_next
;
3345 struct search_domain
*dom
, *dom_next
;
3349 reply_callback(req_head
, 0, DNS_ERR_SHUTDOWN
, NULL
);
3350 request_finished(req_head
, &req_head
);
3352 while (req_waiting_head
) {
3354 reply_callback(req_waiting_head
, 0, DNS_ERR_SHUTDOWN
, NULL
);
3355 request_finished(req_waiting_head
, &req_waiting_head
);
3357 global_requests_inflight
= global_requests_waiting
= 0;
3359 for (server
= server_head
; server
; server
= server_next
) {
3360 server_next
= server
->next
;
3361 if (server
->socket
>= 0)
3362 CLOSE_SOCKET(server
->socket
);
3363 (void) event_del(&server
->event
);
3364 del_timeout_event(server
);
3367 if (server_next
== server_head
)
3371 global_good_nameservers
= 0;
3373 if (global_search_state
) {
3374 for (dom
= global_search_state
->head
; dom
; dom
= dom_next
) {
3375 dom_next
= dom
->next
;
3379 CLEAR(global_search_state
);
3380 mm_free(global_search_state
);
3381 global_search_state
= NULL
;
3383 evdns_log_fn
= NULL
;
3388 main_callback(int result
, char type
, int count
, int ttl
,
3389 void *addrs
, void *orig
) {
3390 char *n
= (char*)orig
;
3392 for (i
= 0; i
< count
; ++i
) {
3393 if (type
== DNS_IPv4_A
) {
3394 printf("%s: %s\n", n
, debug_ntoa(((u32
*)addrs
)[i
]));
3395 } else if (type
== DNS_PTR
) {
3396 printf("%s: %s\n", n
, ((char**)addrs
)[i
]);
3400 printf("%s: No answer (%d)\n", n
, result
);
3405 evdns_server_callback(struct evdns_server_request
*req
, void *data
)
3409 /* dummy; give 192.168.11.11 as an answer for all A questions,
3410 * give foo.bar.example.com as an answer for all PTR questions. */
3411 for (i
= 0; i
< req
->nquestions
; ++i
) {
3412 u32 ans
= htonl(0xc0a80b0bUL
);
3413 if (req
->questions
[i
]->type
== EVDNS_TYPE_A
&&
3414 req
->questions
[i
]->dns_question_class
== EVDNS_CLASS_INET
) {
3415 printf(" -- replying for %s (A)\n", req
->questions
[i
]->name
);
3416 r
= evdns_server_request_add_a_reply(req
, req
->questions
[i
]->name
,
3419 printf("eeep, didn't work.\n");
3420 } else if (req
->questions
[i
]->type
== EVDNS_TYPE_PTR
&&
3421 req
->questions
[i
]->dns_question_class
== EVDNS_CLASS_INET
) {
3422 printf(" -- replying for %s (PTR)\n", req
->questions
[i
]->name
);
3423 r
= evdns_server_request_add_ptr_reply(req
, NULL
, req
->questions
[i
]->name
,
3424 "foo.bar.example.com", 10);
3426 printf(" -- skipping %s [%d %d]\n", req
->questions
[i
]->name
,
3427 req
->questions
[i
]->type
, req
->questions
[i
]->dns_question_class
);
3431 r
= evdns_server_request_respond(req
, 0);
3433 printf("eeek, couldn't send reply.\n");
3437 logfn(int is_warn
, const char *msg
) {
3439 fprintf(stderr
, "%s\n", msg
);
3442 main(int c
, char **v
) {
3444 int reverse
= 0, verbose
= 1, servertest
= 0;
3446 fprintf(stderr
, "syntax: %s [-x] [-v] hostname\n", v
[0]);
3447 fprintf(stderr
, "syntax: %s [-servertest]\n", v
[0]);
3451 while (idx
< c
&& v
[idx
][0] == '-') {
3452 if (!strcmp(v
[idx
], "-x"))
3454 else if (!strcmp(v
[idx
], "-v"))
3456 else if (!strcmp(v
[idx
], "-servertest"))
3459 fprintf(stderr
, "Unknown option %s\n", v
[idx
]);
3464 evdns_set_log_fn(logfn
);
3465 evdns_resolv_conf_parse(DNS_OPTION_NAMESERVERS
, "/etc/resolv.conf");
3468 struct sockaddr_in my_addr
;
3469 sock
= tor_open_socket(PF_INET
, SOCK_DGRAM
, 0);
3470 fcntl(sock
, F_SETFL
, O_NONBLOCK
);
3471 my_addr
.sin_family
= AF_INET
;
3472 my_addr
.sin_port
= htons(10053);
3473 my_addr
.sin_addr
.s_addr
= INADDR_ANY
;
3474 if (bind(sock
, (struct sockaddr
*)&my_addr
, sizeof(my_addr
))<0) {
3478 evdns_add_server_port(sock
, 0, evdns_server_callback
, NULL
);
3480 for (; idx
< c
; ++idx
) {
3482 struct in_addr addr
;
3483 if (!inet_aton(v
[idx
], &addr
)) {
3484 fprintf(stderr
, "Skipping non-IP %s\n", v
[idx
]);
3487 fprintf(stderr
, "resolving %s...\n",v
[idx
]);
3488 evdns_resolve_reverse(&addr
, 0, main_callback
, v
[idx
]);
3490 fprintf(stderr
, "resolving (fwd) %s...\n",v
[idx
]);
3491 evdns_resolve_ipv4(v
[idx
], 0, main_callback
, v
[idx
]);
3500 /* Local Variables: */
3502 /* c-basic-offset: 4 */
3503 /* indent-tabs-mode: t */