1
2 /*
3 * Copyright (C) Igor Sysoev
4 */
5
6
7 #include <ngx_config.h>
8 #include <ngx_core.h>
9 #include <ngx_event.h>
10
11
12 #define NGX_RESOLVER_UDP_SIZE 4096
13
14
15 typedef struct {
16 u_char ident_hi;
17 u_char ident_lo;
18 u_char flags_hi;
19 u_char flags_lo;
20 u_char nqs_hi;
21 u_char nqs_lo;
22 u_char nan_hi;
23 u_char nan_lo;
24 u_char nns_hi;
25 u_char nns_lo;
26 u_char nar_hi;
27 u_char nar_lo;
28 } ngx_resolver_query_t;
29
30
31 typedef struct {
32 u_char type_hi;
33 u_char type_lo;
34 u_char class_hi;
35 u_char class_lo;
36 } ngx_resolver_qs_t;
37
38
39 typedef struct {
40 u_char type_hi;
41 u_char type_lo;
42 u_char class_hi;
43 u_char class_lo;
44 u_char ttl[4];
45 u_char len_hi;
46 u_char len_lo;
47 } ngx_resolver_an_t;
48
49
50 ngx_int_t ngx_udp_connect(ngx_udp_connection_t *uc);
51
52
53 static void ngx_resolver_cleanup(void *data);
54 static void ngx_resolver_cleanup_tree(ngx_resolver_t *r, ngx_rbtree_t *tree);
55 static ngx_int_t ngx_resolve_name_locked(ngx_resolver_t *r,
56 ngx_resolver_ctx_t *ctx);
57 static void ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree,
58 ngx_queue_t *queue);
59 static ngx_int_t ngx_resolver_send_query(ngx_resolver_t *r,
60 ngx_resolver_node_t *rn);
61 static ngx_int_t ngx_resolver_create_name_query(ngx_resolver_node_t *rn,
62 ngx_resolver_ctx_t *ctx);
63 static ngx_int_t ngx_resolver_create_addr_query(ngx_resolver_node_t *rn,
64 ngx_resolver_ctx_t *ctx);
65 static void ngx_resolver_resend_handler(ngx_event_t *ev);
66 static time_t ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree,
67 ngx_queue_t *queue);
68 static void ngx_resolver_read_response(ngx_event_t *rev);
69 static void ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf,
70 size_t n);
71 static void ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t n,
72 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans);
73 static void ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
74 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan);
75 static ngx_resolver_node_t *ngx_resolver_lookup_name(ngx_resolver_t *r,
76 ngx_str_t *name, uint32_t hash);
77 static ngx_resolver_node_t *ngx_resolver_lookup_addr(ngx_resolver_t *r,
78 in_addr_t addr);
79 static void ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
80 ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
81 static ngx_int_t ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name,
82 u_char *buf, u_char *src, u_char *last);
83 static void ngx_resolver_timeout_handler(ngx_event_t *ev);
84 static void ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn);
85 static void *ngx_resolver_alloc(ngx_resolver_t *r, size_t size);
86 static void *ngx_resolver_calloc(ngx_resolver_t *r, size_t size);
87 static void ngx_resolver_free(ngx_resolver_t *r, void *p);
88 static void ngx_resolver_free_locked(ngx_resolver_t *r, void *p);
89 static void *ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size);
90
91
92 /* STUB: ngx_peer_addr_t * */
93
94 ngx_resolver_t *
95 ngx_resolver_create(ngx_conf_t *cf, ngx_peer_addr_t *addr)
96 {
97 ngx_resolver_t *r;
98 ngx_pool_cleanup_t *cln;
99 ngx_udp_connection_t *uc;
100
101 cln = ngx_pool_cleanup_add(cf->pool, 0);
102 if (cln == NULL) {
103 return NULL;
104 }
105
106 cln->handler = ngx_resolver_cleanup;
107
108 r = ngx_calloc(sizeof(ngx_resolver_t), cf->log);
109 if (r == NULL) {
110 return NULL;
111 }
112
113 cln->data = r;
114
115 r->event = ngx_calloc(sizeof(ngx_event_t), cf->log);
116 if (r->event == NULL) {
117 return NULL;
118 }
119
120 ngx_rbtree_init(&r->name_rbtree, &r->name_sentinel,
121 ngx_resolver_rbtree_insert_value);
122
123 ngx_rbtree_init(&r->addr_rbtree, &r->addr_sentinel,
124 ngx_rbtree_insert_value);
125
126 ngx_queue_init(&r->name_resend_queue);
127 ngx_queue_init(&r->addr_resend_queue);
128
129 ngx_queue_init(&r->name_expire_queue);
130 ngx_queue_init(&r->addr_expire_queue);
131
132 r->event->handler = ngx_resolver_resend_handler;
133 r->event->data = r;
134 r->event->log = &cf->cycle->new_log;
135 r->ident = -1;
136
137 r->resend_timeout = 5;
138 r->expire = 30;
139 r->valid = 300;
140
141 r->log = &cf->cycle->new_log;
142 r->log_level = NGX_LOG_ALERT;
143
144 if (addr) {
145 uc = ngx_calloc(sizeof(ngx_udp_connection_t), cf->log);
146 if (uc == NULL) {
147 return NULL;
148 }
149
150 r->udp_connection = uc;
151
152 uc->sockaddr = addr->sockaddr;
153 uc->socklen = addr->socklen;
154 uc->server = addr->name;
155 uc->log = &cf->cycle->new_log;
156 }
157
158 return r;
159 }
160
161
162 static void
163 ngx_resolver_cleanup(void *data)
164 {
165 ngx_resolver_t *r = data;
166
167 if (r) {
168 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
169 "cleanup resolver");
170
171 ngx_resolver_cleanup_tree(r, &r->name_rbtree);
172
173 ngx_resolver_cleanup_tree(r, &r->addr_rbtree);
174
175 if (r->event) {
176 ngx_free(r->event);
177 }
178
179 if (r->udp_connection) {
180 if (r->udp_connection->connection) {
181 ngx_close_connection(r->udp_connection->connection);
182 }
183
184 ngx_free(r->udp_connection);
185 }
186
187 ngx_free(r);
188 }
189 }
190
191
192 static void
193 ngx_resolver_cleanup_tree(ngx_resolver_t *r, ngx_rbtree_t *tree)
194 {
195 ngx_resolver_ctx_t *ctx, *next;
196 ngx_resolver_node_t *rn;
197
198 while (tree->root != tree->sentinel) {
199
200 rn = (ngx_resolver_node_t *) ngx_rbtree_min(tree->root, tree->sentinel);
201
202 ngx_queue_remove(&rn->queue);
203
204 for (ctx = rn->waiting; ctx; ctx = next) {
205 next = ctx->next;
206
207 if (ctx->event) {
208 ngx_resolver_free(r, ctx->event);
209 }
210
211 ngx_resolver_free(r, ctx);
212 }
213
214 ngx_rbtree_delete(tree, &rn->node);
215
216 ngx_resolver_free_node(r, rn);
217 }
218 }
219
220
221 ngx_resolver_ctx_t *
222 ngx_resolve_start(ngx_resolver_t *r, ngx_resolver_ctx_t *temp)
223 {
224 in_addr_t addr;
225 ngx_resolver_ctx_t *ctx;
226
227 if (temp) {
228 addr = ngx_inet_addr(temp->name.data, temp->name.len);
229
230 if (addr != INADDR_NONE) {
231 temp->resolver = r;
232 temp->state = NGX_OK;
233 temp->naddrs = 1;
234 temp->addrs = &temp->addr;
235 temp->addr = addr;
236 temp->quick = 1;
237
238 return temp;
239 }
240 }
241
242 if (r->udp_connection == NULL) {
243 return NGX_NO_RESOLVER;
244 }
245
246 ctx = ngx_resolver_calloc(r, sizeof(ngx_resolver_ctx_t));
247
248 if (ctx) {
249 ctx->resolver = r;
250 }
251
252 return ctx;
253 }
254
255
256 ngx_int_t
257 ngx_resolve_name(ngx_resolver_ctx_t *ctx)
258 {
259 ngx_int_t rc;
260 ngx_resolver_t *r;
261
262 r = ctx->resolver;
263
264 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
265 "resolve: \"%V\"", &ctx->name);
266
267 if (ctx->quick) {
268 ctx->handler(ctx);
269 return NGX_OK;
270 }
271
272 /* lock name mutex */
273
274 rc = ngx_resolve_name_locked(r, ctx);
275
276 if (rc == NGX_OK) {
277 return NGX_OK;
278 }
279
280 /* unlock name mutex */
281
282 if (rc == NGX_AGAIN) {
283 return NGX_OK;
284 }
285
286 /* NGX_ERROR */
287
288 if (ctx->event) {
289 ngx_resolver_free(r, ctx->event);
290 }
291
292 ngx_resolver_free(r, ctx);
293
294 return NGX_ERROR;
295 }
296
297
298 void
299 ngx_resolve_name_done(ngx_resolver_ctx_t *ctx)
300 {
301 uint32_t hash;
302 ngx_resolver_t *r;
303 ngx_resolver_ctx_t *w, **p;
304 ngx_resolver_node_t *rn;
305
306 r = ctx->resolver;
307
308 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
309 "resolve name done: %i", ctx->state);
310
311 if (ctx->quick) {
312 return;
313 }
314
315 if (ctx->event && ctx->event->timer_set) {
316 ngx_del_timer(ctx->event);
317 }
318
319 /* lock name mutex */
320
321 if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
322
323 hash = ngx_crc32_short(ctx->name.data, ctx->name.len);
324
325 rn = ngx_resolver_lookup_name(r, &ctx->name, hash);
326
327 if (rn) {
328 p = &rn->waiting;
329 w = rn->waiting;
330
331 while (w) {
332 if (w == ctx) {
333 *p = w->next;
334
335 goto done;
336 }
337
338 p = &w->next;
339 w = w->next;
340 }
341 }
342
343 ngx_log_error(NGX_LOG_ALERT, r->log, 0,
344 "could not cancel %V resolving", &ctx->name);
345 }
346
347 done:
348
349 ngx_resolver_expire(r, &r->name_rbtree, &r->name_expire_queue);
350
351 /* unlock name mutex */
352
353 /* lock alloc mutex */
354
355 if (ctx->event) {
356 ngx_resolver_free_locked(r, ctx->event);
357 }
358
359 ngx_resolver_free_locked(r, ctx);
360
361 /* unlock alloc mutex */
362 }
363
364
365 /* NGX_RESOLVE_A only */
366
367 static ngx_int_t
368 ngx_resolve_name_locked(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx)
369 {
370 uint32_t hash;
371 in_addr_t addr, *addrs;
372 ngx_int_t rc;
373 ngx_uint_t naddrs;
374 ngx_resolver_ctx_t *next;
375 ngx_resolver_node_t *rn;
376
377 hash = ngx_crc32_short(ctx->name.data, ctx->name.len);
378
379 rn = ngx_resolver_lookup_name(r, &ctx->name, hash);
380
381 if (rn) {
382
383 if (rn->valid >= ngx_time()) {
384
385 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached");
386
387 ngx_queue_remove(&rn->queue);
388
389 rn->expire = ngx_time() + r->expire;
390
391 ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
392
393 naddrs = rn->naddrs;
394
395 if (naddrs) {
396
397 /* NGX_RESOLVE_A answer */
398
399 if (naddrs != 1) {
400 addr = 0;
401 addrs = ngx_resolver_dup(r, rn->u.addrs,
402 naddrs * sizeof(in_addr_t));
403 if (addrs == NULL) {
404 return NGX_ERROR;
405 }
406
407 } else {
408 addr = rn->u.addr;
409 addrs = NULL;
410 }
411
412 ctx->next = rn->waiting;
413 rn->waiting = NULL;
414
415 /* unlock name mutex */
416
417 do {
418 ctx->state = NGX_OK;
419 ctx->naddrs = naddrs;
420 ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs;
421 ctx->addr = addr;
422 next = ctx->next;
423
424 ctx->handler(ctx);
425
426 ctx = next;
427 } while (ctx);
428
429 if (addrs) {
430 ngx_resolver_free(r, addrs);
431 }
432
433 return NGX_OK;
434 }
435
436 /* NGX_RESOLVE_CNAME */
437
438 if (ctx->recursion++ < NGX_RESOLVER_MAX_RECURSION) {
439
440 ctx->name.len = rn->cnlen;
441 ctx->name.data = rn->u.cname;
442
443 return ngx_resolve_name_locked(r, ctx);
444 }
445
446 ctx->next = rn->waiting;
447 rn->waiting = NULL;
448
449 /* unlock name mutex */
450
451 do {
452 ctx->state = NGX_RESOLVE_NXDOMAIN;
453 next = ctx->next;
454
455 ctx->handler(ctx);
456
457 ctx = next;
458 } while (ctx);
459
460 return NGX_OK;
461 }
462
463 if (rn->waiting) {
464
465 ctx->next = rn->waiting;
466 rn->waiting = ctx;
467
468 return NGX_AGAIN;
469 }
470
471 ngx_queue_remove(&rn->queue);
472
473 /* lock alloc mutex */
474
475 ngx_resolver_free_locked(r, rn->query);
476 rn->query = NULL;
477
478 if (rn->cnlen) {
479 ngx_resolver_free_locked(r, rn->u.cname);
480 }
481
482 if (rn->naddrs > 1) {
483 ngx_resolver_free_locked(r, rn->u.addrs);
484 }
485
486 /* unlock alloc mutex */
487
488 } else {
489
490 rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
491 if (rn == NULL) {
492 return NGX_ERROR;
493 }
494
495 rn->name = ngx_resolver_dup(r, ctx->name.data, ctx->name.len);
496 if (rn->name == NULL) {
497 ngx_resolver_free(r, rn);
498 return NGX_ERROR;
499 }
500
501 rn->node.key = hash;
502 rn->nlen = (u_short) ctx->name.len;
503 rn->query = NULL;
504
505 ngx_rbtree_insert(&r->name_rbtree, &rn->node);
506 }
507
508 rc = ngx_resolver_create_name_query(rn, ctx);
509
510 if (rc == NGX_ERROR) {
511 goto failed;
512 }
513
514 if (rc == NGX_DECLINED) {
515 ngx_rbtree_delete(&r->name_rbtree, &rn->node);
516
517 ngx_resolver_free(r, rn->query);
518 ngx_resolver_free(r, rn->name);
519 ngx_resolver_free(r, rn);
520
521 ctx->state = NGX_RESOLVE_NXDOMAIN;
522 ctx->handler(ctx);
523
524 return NGX_OK;
525 }
526
527 if (ngx_resolver_send_query(r, rn) != NGX_OK) {
528 goto failed;
529 }
530
531 if (ctx->event == NULL) {
532 ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t));
533 if (ctx->event == NULL) {
534 goto failed;
535 }
536
537 ctx->event->handler = ngx_resolver_timeout_handler;
538 ctx->event->data = ctx;
539 ctx->event->log = r->log;
540 ctx->ident = -1;
541
542 ngx_add_timer(ctx->event, ctx->timeout);
543 }
544
545 if (ngx_queue_empty(&r->name_resend_queue)) {
546 ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
547 }
548
549 rn->expire = ngx_time() + r->resend_timeout;
550
551 ngx_queue_insert_head(&r->name_resend_queue, &rn->queue);
552
553 rn->cnlen = 0;
554 rn->naddrs = 0;
555 rn->valid = 0;
556 rn->waiting = ctx;
557
558 ctx->state = NGX_AGAIN;
559
560 return NGX_AGAIN;
561
562 failed:
563
564 ngx_rbtree_delete(&r->name_rbtree, &rn->node);
565
566 if (rn->query) {
567 ngx_resolver_free(r, rn->query);
568 }
569
570 ngx_resolver_free(r, rn->name);
571
572 ngx_resolver_free(r, rn);
573
574 return NGX_ERROR;
575 }
576
577
578 ngx_int_t
579 ngx_resolve_addr(ngx_resolver_ctx_t *ctx)
580 {
581 u_char *name;
582 ngx_resolver_t *r;
583 ngx_resolver_node_t *rn;
584
585 r = ctx->resolver;
586
587 ctx->addr = ntohl(ctx->addr);
588
589 /* lock addr mutex */
590
591 rn = ngx_resolver_lookup_addr(r, ctx->addr);
592
593 if (rn) {
594
595 if (rn->valid >= ngx_time()) {
596
597 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached");
598
599 ngx_queue_remove(&rn->queue);
600
601 rn->expire = ngx_time() + r->expire;
602
603 ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue);
604
605 name = ngx_resolver_dup(r, rn->name, rn->nlen);
606 if (name == NULL) {
607 goto failed;
608 }
609
610 ctx->name.len = rn->nlen;
611 ctx->name.data = name;
612
613 /* unlock addr mutex */
614
615 ctx->state = NGX_OK;
616
617 ctx->handler(ctx);
618
619 ngx_resolver_free(r, name);
620
621 return NGX_OK;
622 }
623
624 if (rn->waiting) {
625
626 ctx->next = rn->waiting;
627 rn->waiting = ctx;
628
629 /* unlock addr mutex */
630
631 return NGX_OK;
632 }
633
634 ngx_queue_remove(&rn->queue);
635
636 ngx_resolver_free(r, rn->query);
637 rn->query = NULL;
638
639 } else {
640 rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
641 if (rn == NULL) {
642 goto failed;
643 }
644
645 rn->node.key = ctx->addr;
646 rn->query = NULL;
647
648 ngx_rbtree_insert(&r->addr_rbtree, &rn->node);
649 }
650
651 if (ngx_resolver_create_addr_query(rn, ctx) != NGX_OK) {
652 goto failed;
653 }
654
655 if (ngx_resolver_send_query(r, rn) != NGX_OK) {
656 goto failed;
657 }
658
659 ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t));
660 if (ctx->event == NULL) {
661 goto failed;
662 }
663
664 ctx->event->handler = ngx_resolver_timeout_handler;
665 ctx->event->data = ctx;
666 ctx->event->log = r->log;
667 ctx->ident = -1;
668
669 ngx_add_timer(ctx->event, ctx->timeout);
670
671 if (ngx_queue_empty(&r->addr_resend_queue)) {
672 ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
673 }
674
675 rn->expire = ngx_time() + r->resend_timeout;
676
677 ngx_queue_insert_head(&r->addr_resend_queue, &rn->queue);
678
679 rn->cnlen = 0;
680 rn->naddrs = 0;
681 rn->name = NULL;
682 rn->nlen = 0;
683 rn->valid = 0;
684 rn->waiting = ctx;
685
686 /* unlock addr mutex */
687
688 ctx->state = NGX_AGAIN;
689
690 return NGX_OK;
691
692 failed:
693
694 if (rn) {
695 ngx_rbtree_delete(&r->addr_rbtree, &rn->node);
696
697 if (rn->query) {
698 ngx_resolver_free(r, rn->query);
699 }
700
701 ngx_resolver_free(r, rn);
702 }
703
704 /* unlock addr mutex */
705
706 if (ctx->event) {
707 ngx_resolver_free(r, ctx->event);
708 }
709
710 ngx_resolver_free(r, ctx);
711
712 return NGX_ERROR;
713 }
714
715
716 void
717 ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx)
718 {
719 in_addr_t addr;
720 ngx_resolver_t *r;
721 ngx_resolver_ctx_t *w, **p;
722 ngx_resolver_node_t *rn;
723
724 r = ctx->resolver;
725
726 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
727 "resolve addr done: %i", ctx->state);
728
729 if (ctx->event && ctx->event->timer_set) {
730 ngx_del_timer(ctx->event);
731 }
732
733 /* lock addr mutex */
734
735 if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
736
737 rn = ngx_resolver_lookup_addr(r, ctx->addr);
738
739 if (rn) {
740 p = &rn->waiting;
741 w = rn->waiting;
742
743 while (w) {
744 if (w == ctx) {
745 *p = w->next;
746
747 goto done;
748 }
749
750 p = &w->next;
751 w = w->next;
752 }
753 }
754
755 addr = ntohl(ctx->addr);
756
757 ngx_log_error(NGX_LOG_ALERT, r->log, 0,
758 "could not cancel %ud.%ud.%ud.%ud resolving",
759 (addr >> 24) & 0xff, (addr >> 16) & 0xff,
760 (addr >> 8) & 0xff, addr & 0xff);
761 }
762
763 done:
764
765 ngx_resolver_expire(r, &r->addr_rbtree, &r->addr_expire_queue);
766
767 /* unlock addr mutex */
768
769 /* lock alloc mutex */
770
771 if (ctx->event) {
772 ngx_resolver_free_locked(r, ctx->event);
773 }
774
775 ngx_resolver_free_locked(r, ctx);
776
777 /* unlock alloc mutex */
778 }
779
780
781 static void
782 ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue)
783 {
784 time_t now;
785 ngx_uint_t i;
786 ngx_queue_t *q;
787 ngx_resolver_node_t *rn;
788
789 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver expire");
790
791 now = ngx_time();
792
793 for (i = 0; i < 2; i++) {
794 if (ngx_queue_empty(queue)) {
795 return;
796 }
797
798 q = ngx_queue_last(queue);
799
800 rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
801
802 if (now <= rn->expire) {
803 return;
804 }
805
806 ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
807 "resolver expire \"%*s\"", (size_t) rn->nlen, rn->name);
808
809 ngx_queue_remove(q);
810
811 ngx_rbtree_delete(tree, &rn->node);
812
813 ngx_resolver_free_node(r, rn);
814 }
815 }
816
817
818 static ngx_int_t
819 ngx_resolver_send_query(ngx_resolver_t *r, ngx_resolver_node_t *rn)
820 {
821 ssize_t n;
822 ngx_udp_connection_t *uc;
823
824 uc = r->udp_connection;
825
826 if (uc->connection == NULL) {
827 if (ngx_udp_connect(uc) != NGX_OK) {
828 return NGX_ERROR;
829 }
830
831 uc->connection->data = r;
832 uc->connection->read->handler = ngx_resolver_read_response;
833 uc->connection->read->resolver = 1;
834 }
835
836 n = ngx_send(uc->connection, rn->query, rn->qlen);
837
838 if (n == -1) {
839 return NGX_ERROR;
840 }
841
842 if ((size_t) n != (size_t) rn->qlen) {
843 ngx_log_error(NGX_LOG_CRIT, uc->log, 0, "send() incomplete");
844 return NGX_ERROR;
845 }
846
847 return NGX_OK;
848 }
849
850
851 static void
852 ngx_resolver_resend_handler(ngx_event_t *ev)
853 {
854 time_t timer, atimer, ntimer;
855 ngx_resolver_t *r;
856
857 r = ev->data;
858
859 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0,
860 "resolver resend handler");
861
862 /* lock name mutex */
863
864 ntimer = ngx_resolver_resend(r, &r->name_rbtree, &r->name_resend_queue);
865
866 /* unlock name mutex */
867
868 /* lock addr mutex */
869
870 atimer = ngx_resolver_resend(r, &r->addr_rbtree, &r->addr_resend_queue);
871
872 /* unlock addr mutex */
873
874 if (ntimer == 0) {
875 timer = atimer;
876
877 } else if (atimer == 0) {
878 timer = ntimer;
879
880 } else {
881 timer = (atimer < ntimer) ? atimer : ntimer;
882 }
883
884 if (timer) {
885 ngx_add_timer(r->event, (ngx_msec_t) (timer * 1000));
886 }
887 }
888
889
890 static time_t
891 ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue)
892 {
893 time_t now;
894 ngx_queue_t *q;
895 ngx_resolver_node_t *rn;
896
897 now = ngx_time();
898
899 for ( ;; ) {
900 if (ngx_queue_empty(queue)) {
901 return 0;
902 }
903
904 q = ngx_queue_last(queue);
905
906 rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
907
908 if (now < rn->expire) {
909 return rn->expire - now;
910 }
911
912 ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
913 "resolver resend \"%*s\" %p",
914 (size_t) rn->nlen, rn->name, rn->waiting);
915
916 ngx_queue_remove(q);
917
918 if (rn->waiting) {
919
920 if (ngx_resolver_send_query(r, rn) == NGX_OK) {
921
922 rn->expire = now + r->resend_timeout;
923
924 ngx_queue_insert_head(queue, &rn->queue);
925 }
926
927 continue;
928 }
929
930 ngx_rbtree_delete(tree, &rn->node);
931
932 ngx_resolver_free_node(r, rn);
933 }
934 }
935
936
937 static void
938 ngx_resolver_read_response(ngx_event_t *rev)
939 {
940 ssize_t n;
941 ngx_connection_t *c;
942 u_char buf[NGX_RESOLVER_UDP_SIZE];
943
944 c = rev->data;
945
946 do {
947 n = ngx_udp_recv(c, buf, NGX_RESOLVER_UDP_SIZE);
948
949 if (n < 0) {
950 return;
951 }
952
953 ngx_resolver_process_response(c->data, buf, n);
954
955 } while (rev->ready);
956 }
957
958
959 static void
960 ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n)
961 {
962 char *err;
963 size_t len;
964 ngx_uint_t i, times, ident, qident, flags, code, nqs, nan,
965 qtype, qclass;
966 ngx_queue_t *q;
967 ngx_resolver_qs_t *qs;
968 ngx_resolver_node_t *rn;
969 ngx_resolver_query_t *query;
970
971 if ((size_t) n < sizeof(ngx_resolver_query_t)) {
972 goto short_response;
973 }
974
975 query = (ngx_resolver_query_t *) buf;
976
977 ident = (query->ident_hi << 8) + query->ident_lo;
978 flags = (query->flags_hi << 8) + query->flags_lo;
979 nqs = (query->nqs_hi << 8) + query->nqs_lo;
980 nan = (query->nan_hi << 8) + query->nan_lo;
981
982 ngx_log_debug6(NGX_LOG_DEBUG_CORE, r->log, 0,
983 "resolver DNS response %ui fl:%04Xui %ui/%ui/%ui/%ui",
984 ident, flags, nqs, nan,
985 (query->nns_hi << 8) + query->nns_lo,
986 (query->nar_hi << 8) + query->nar_lo);
987
988 if (!(flags & 0x8000)) {
989 ngx_log_error(r->log_level, r->log, 0,
990 "invalid DNS response %ui fl:%04Xui", ident, flags);
991 return;
992 }
993
994 code = flags & 0x7f;
995
996 if (code == NGX_RESOLVE_FORMERR) {
997
998 times = 0;
999
1000 for (q = ngx_queue_head(&r->name_resend_queue);
1001 q != ngx_queue_sentinel(&r->name_resend_queue) || times++ < 100;
1002 q = ngx_queue_next(q))
1003 {
1004 rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
1005 qident = (rn->query[0] << 8) + rn->query[1];
1006
1007 if (qident == ident) {
1008 ngx_log_error(r->log_level, r->log, 0,
1009 "DNS error (%ui: %s), query id:%ui, name:\"%*s\"",
1010 code, ngx_resolver_strerror(code), ident,
1011 rn->nlen, rn->name);
1012 return;
1013 }
1014 }
1015
1016 goto dns_error;
1017 }
1018
1019 if (code > NGX_RESOLVE_REFUSED) {
1020 goto dns_error;
1021 }
1022
1023 if (nqs != 1) {
1024 err = "invalid number of questions in DNS response";
1025 goto done;
1026 }
1027
1028 i = sizeof(ngx_resolver_query_t);
1029
1030 while (i < (ngx_uint_t) n) {
1031 if (buf[i] == '\0') {
1032 goto found;
1033 }
1034
1035 len = buf[i];
1036 i += 1 + len;
1037 }
1038
1039 goto short_response;
1040
1041 found:
1042
1043 if (i++ == 0) {
1044 err = "zero-length domain name in DNS response";
1045 goto done;
1046 }
1047
1048 if (i + sizeof(ngx_resolver_qs_t) + nan * (2 + sizeof(ngx_resolver_an_t))
1049 > (ngx_uint_t) n)
1050 {
1051 goto short_response;
1052 }
1053
1054 qs = (ngx_resolver_qs_t *) &buf[i];
1055
1056 qtype = (qs->type_hi << 8) + qs->type_lo;
1057 qclass = (qs->class_hi << 8) + qs->class_lo;
1058
1059 ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
1060 "resolver DNS response qt:%ui cl:%ui", qtype, qclass);
1061
1062 if (qclass != 1) {
1063 ngx_log_error(r->log_level, r->log, 0,
1064 "unknown query class %ui in DNS response", qclass);
1065 return;
1066 }
1067
1068 switch (qtype) {
1069
1070 case NGX_RESOLVE_A:
1071
1072 ngx_resolver_process_a(r, buf, n, ident, code, nan,
1073 i + sizeof(ngx_resolver_qs_t));
1074
1075 break;
1076
1077 case NGX_RESOLVE_PTR:
1078
1079 ngx_resolver_process_ptr(r, buf, n, ident, code, nan);
1080
1081 break;
1082
1083 default:
1084 ngx_log_error(r->log_level, r->log, 0,
1085 "unknown query type %ui in DNS response", qtype);
1086 return;
1087 }
1088
1089 return;
1090
1091 short_response:
1092
1093 err = "short dns response";
1094
1095 done:
1096
1097 ngx_log_error(r->log_level, r->log, 0, err);
1098
1099 return;
1100
1101 dns_error:
1102
1103 ngx_log_error(r->log_level, r->log, 0,
1104 "DNS error (%ui: %s), query id:%ui",
1105 code, ngx_resolver_strerror(code), ident);
1106 return;
1107 }
1108
1109
1110 static void
1111 ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
1112 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans)
1113 {
1114 char *err;
1115 u_char *cname;
1116 size_t len;
1117 uint32_t hash;
1118 in_addr_t addr, *addrs;
1119 ngx_str_t name;
1120 ngx_uint_t qtype, qident, naddrs, a, i, n, start;
1121 ngx_resolver_an_t *an;
1122 ngx_resolver_ctx_t *ctx, *next;
1123 ngx_resolver_node_t *rn;
1124
1125 if (ngx_resolver_copy(r, &name, buf, &buf[12], &buf[last]) != NGX_OK) {
1126 return;
1127 }
1128
1129 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qs:%V", &name);
1130
1131 hash = ngx_crc32_short(name.data, name.len);
1132
1133 /* lock name mutex */
1134
1135 rn = ngx_resolver_lookup_name(r, &name, hash);
1136
1137 if (rn == NULL || rn->query == NULL) {
1138 ngx_log_error(r->log_level, r->log, 0,
1139 "unexpected response for %V", &name);
1140 goto failed;
1141 }
1142
1143 qident = (rn->query[0] << 8) + rn->query[1];
1144
1145 if (ident != qident) {
1146 ngx_log_error(r->log_level, r->log, 0,
1147 "wrong ident %ui response for %V, expect %ui",
1148 ident, &name, qident);
1149 goto failed;
1150 }
1151
1152 ngx_resolver_free(r, name.data);
1153
1154 if (code == 0 && nan == 0) {
1155 code = 3; /* NXDOMAIN */
1156 }
1157
1158 if (code) {
1159 next = rn->waiting;
1160 rn->waiting = NULL;
1161
1162 ngx_queue_remove(&rn->queue);
1163
1164 ngx_rbtree_delete(&r->name_rbtree, &rn->node);
1165
1166 ngx_resolver_free_node(r, rn);
1167
1168 /* unlock name mutex */
1169
1170 while (next) {
1171 ctx = next;
1172 ctx->state = code;
1173 next = ctx->next;
1174
1175 ctx->handler(ctx);
1176 }
1177
1178 return;
1179 }
1180
1181 i = ans;
1182 naddrs = 0;
1183 addr = 0;
1184 addrs = NULL;
1185 cname = NULL;
1186 qtype = 0;
1187
1188 for (a = 0; a < nan; a++) {
1189
1190 start = i;
1191
1192 while (i < last) {
1193
1194 if (buf[i] & 0xc0) {
1195 i += 2;
1196 goto found;
1197 }
1198
1199 if (buf[i] == 0) {
1200 i++;
1201 goto test_length;
1202 }
1203
1204 i += 1 + buf[i];
1205 }
1206
1207 goto short_response;
1208
1209 test_length:
1210
1211 if (i - start < 2) {
1212 err = "invalid name in dns response";
1213 goto invalid;
1214 }
1215
1216 found:
1217
1218 if (i + sizeof(ngx_resolver_an_t) >= last) {
1219 goto short_response;
1220 }
1221
1222 an = (ngx_resolver_an_t *) &buf[i];
1223
1224 qtype = (an->type_hi << 8) + an->type_lo;
1225 len = (an->len_hi << 8) + an->len_lo;
1226
1227 if (qtype == NGX_RESOLVE_A) {
1228
1229 i += sizeof(ngx_resolver_an_t);
1230
1231 if (i + len > last) {
1232 goto short_response;
1233 }
1234
1235 addr = htonl((buf[i] << 24) + (buf[i + 1] << 16)
1236 + (buf[i + 2] << 8) + (buf[i + 3]));
1237
1238 naddrs++;
1239
1240 i += len;
1241
1242 } else if (qtype == NGX_RESOLVE_CNAME) {
1243 cname = &buf[i] + sizeof(ngx_resolver_an_t);
1244 i += sizeof(ngx_resolver_an_t) + len;
1245
1246 } else if (qtype == NGX_RESOLVE_DNAME) {
1247 i += sizeof(ngx_resolver_an_t) + len;
1248
1249 } else {
1250 ngx_log_error(r->log_level, r->log, 0,
1251 "unexpected qtype %ui", qtype);
1252 }
1253 }
1254
1255 ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
1256 "resolver naddrs:%ui cname:%p", naddrs, cname);
1257
1258 if (naddrs) {
1259
1260 if (naddrs == 1) {
1261 rn->u.addr = addr;
1262
1263 } else {
1264
1265 addrs = ngx_resolver_alloc(r, naddrs * sizeof(in_addr_t));
1266 if (addrs == NULL) {
1267 return;
1268 }
1269
1270 n = 0;
1271 i = ans;
1272
1273 for (a = 0; a < nan; a++) {
1274
1275 for ( ;; ) {
1276
1277 if (buf[i] & 0xc0) {
1278 i += 2;
1279 goto ok;
1280 }
1281
1282 if (buf[i] == 0) {
1283 i++;
1284 goto ok;
1285 }
1286
1287 i += 1 + buf[i];
1288 }
1289
1290 ok:
1291
1292 an = (ngx_resolver_an_t *) &buf[i];
1293
1294 qtype = (an->type_hi << 8) + an->type_lo;
1295 len = (an->len_hi << 8) + an->len_lo;
1296
1297 i += sizeof(ngx_resolver_an_t);
1298
1299 if (qtype == NGX_RESOLVE_A) {
1300
1301 addrs[n++] = htonl((buf[i] << 24) + (buf[i + 1] << 16)
1302 + (buf[i + 2] << 8) + (buf[i + 3]));
1303
1304 if (n == naddrs) {
1305 break;
1306 }
1307 }
1308
1309 i += len;
1310 }
1311
1312 rn->u.addrs = addrs;
1313
1314 addrs = ngx_resolver_dup(r, rn->u.addrs,
1315 naddrs * sizeof(in_addr_t));
1316 if (addrs == NULL) {
1317 return;
1318 }
1319 }
1320
1321 rn->naddrs = (u_short) naddrs;
1322
1323 ngx_queue_remove(&rn->queue);
1324
1325 rn->valid = ngx_time() + r->valid;
1326 rn->expire = ngx_time() + r->expire;
1327
1328 ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
1329
1330 next = rn->waiting;
1331 rn->waiting = NULL;
1332
1333 /* unlock name mutex */
1334
1335 while (next) {
1336 ctx = next;
1337 ctx->state = NGX_OK;
1338 ctx->naddrs = naddrs;
1339 ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs;
1340 ctx->addr = addr;
1341 next = ctx->next;
1342
1343 ctx->handler(ctx);
1344 }
1345
1346 if (naddrs > 1) {
1347 ngx_resolver_free(r, addrs);
1348 }
1349
1350 return;
1351
1352 } else if (cname) {
1353
1354 /* CNAME only */
1355
1356 if (ngx_resolver_copy(r, &name, buf, cname, &buf[last]) != NGX_OK) {
1357 return;
1358 }
1359
1360 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
1361 "resolver cname:\"%V\"", &name);
1362
1363 ngx_queue_remove(&rn->queue);
1364
1365 rn->cnlen = (u_short) name.len;
1366 rn->u.cname = name.data;
1367 rn->valid = ngx_time() + r->valid;
1368 rn->expire = ngx_time() + r->expire;
1369
1370 ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
1371
1372 ctx = rn->waiting;
1373 rn->waiting = NULL;
1374
1375 if (ctx) {
1376 ctx->name = name;
1377
1378 (void) ngx_resolve_name_locked(r, ctx);
1379 }
1380
1381 return;
1382 }
1383
1384 ngx_log_error(r->log_level, r->log, 0,
1385 "no A or CNAME types in DNS responses, unknown query type: %ui",
1386 qtype);
1387 return;
1388
1389 short_response:
1390
1391 err = "short dns response";
1392
1393 invalid:
1394
1395 /* unlock name mutex */
1396
1397 ngx_log_error(r->log_level, r->log, 0, err);
1398
1399 return;
1400
1401 failed:
1402
1403 /* unlock name mutex */
1404
1405 ngx_resolver_free(r, name.data);
1406
1407 return;
1408 }
1409
1410
1411 static void
1412 ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
1413 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan)
1414 {
1415 char *err;
1416 size_t len;
1417 in_addr_t addr;
1418 ngx_int_t digit;
1419 ngx_str_t name;
1420 ngx_uint_t i, mask, qtype, qclass, qident;
1421 ngx_resolver_an_t *an;
1422 ngx_resolver_ctx_t *ctx, *next;
1423 ngx_resolver_node_t *rn;
1424
1425 if (ngx_resolver_copy(r, NULL, buf, &buf[12], &buf[n]) != NGX_OK) {
1426 goto invalid_in_addr_arpa;
1427 }
1428
1429 addr = 0;
1430 i = 12;
1431
1432 for (mask = 0; mask < 32; mask += 8) {
1433 len = buf[i++];
1434
1435 digit = ngx_atoi(&buf[i], len);
1436 if (digit == NGX_ERROR || digit > 255) {
1437 goto invalid_in_addr_arpa;
1438 }
1439
1440 addr += digit << mask;
1441 i += len;
1442 }
1443
1444 if (ngx_strcmp(&buf[i], "\7in-addr\4arpa") != 0) {
1445 goto invalid_in_addr_arpa;
1446 }
1447
1448 /* lock addr mutex */
1449
1450 rn = ngx_resolver_lookup_addr(r, addr);
1451
1452 if (rn == NULL || rn->query == NULL) {
1453 ngx_log_error(r->log_level, r->log, 0,
1454 "unexpected response for %ud.%ud.%ud.%ud",
1455 (addr >> 24) & 0xff, (addr >> 16) & 0xff,
1456 (addr >> 8) & 0xff, addr & 0xff);
1457 goto failed;
1458 }
1459
1460 qident = (rn->query[0] << 8) + rn->query[1];
1461
1462 if (ident != qident) {
1463 ngx_log_error(r->log_level, r->log, 0,
1464 "wrong ident %ui response for %ud.%ud.%ud.%ud, expect %ui",
1465 ident, (addr >> 24) & 0xff, (addr >> 16) & 0xff,
1466 (addr >> 8) & 0xff, addr & 0xff, qident);
1467 goto failed;
1468 }
1469
1470 if (code == 0 && nan == 0) {
1471 code = 3; /* NXDOMAIN */
1472 }
1473
1474 if (code) {
1475 next = rn->waiting;
1476 rn->waiting = NULL;
1477
1478 ngx_queue_remove(&rn->queue);
1479
1480 ngx_rbtree_delete(&r->addr_rbtree, &rn->node);
1481
1482 ngx_resolver_free_node(r, rn);
1483
1484 /* unlock addr mutex */
1485
1486 while (next) {
1487 ctx = next;
1488 ctx->state = code;
1489 next = ctx->next;
1490
1491 ctx->handler(ctx);
1492 }
1493
1494 return;
1495 }
1496
1497 i += sizeof("\7in-addr\4arpa") + sizeof(ngx_resolver_qs_t);
1498
1499 if (i + 2 + sizeof(ngx_resolver_an_t) > (ngx_uint_t) n) {
1500 goto short_response;
1501 }
1502
1503 /* compression pointer to "XX.XX.XX.XX.in-addr.arpa */
1504
1505 if (buf[i] != 0xc0 || buf[i + 1] != 0x0c) {
1506 err = "invalid in-addr.arpa name in DNS response";
1507 goto invalid;
1508 }
1509
1510 an = (ngx_resolver_an_t *) &buf[i + 2];
1511
1512 qtype = (an->type_hi << 8) + an->type_lo;
1513 qclass = (an->class_hi << 8) + an->class_lo;
1514 len = (an->len_hi << 8) + an->len_lo;
1515
1516 ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
1517 "resolver qt:%ui cl:%ui len:%uz", qtype, qclass, len);
1518
1519 i += 2 + sizeof(ngx_resolver_an_t);
1520
1521 if (i + len > (ngx_uint_t) n) {
1522 goto short_response;
1523 }
1524
1525 if (ngx_resolver_copy(r, &name, buf, &buf[i], &buf[n]) != NGX_OK) {
1526 return;
1527 }
1528
1529 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver an:%V", &name);
1530
1531 if (name.len != (size_t) rn->nlen
1532 || ngx_strncmp(name.data, rn->name, name.len) != 0)
1533 {
1534 if (rn->nlen) {
1535 ngx_resolver_free(r, rn->name);
1536 }
1537
1538 rn->nlen = (u_short) name.len;
1539 rn->name = name.data;
1540
1541 name.data = ngx_resolver_dup(r, rn->name, name.len);
1542 if (name.data == NULL) {
1543 goto failed;
1544 }
1545 }
1546
1547 ngx_queue_remove(&rn->queue);
1548
1549 rn->valid = ngx_time() + r->valid;
1550 rn->expire = ngx_time() + r->expire;
1551
1552 ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue);
1553
1554 next = rn->waiting;
1555 rn->waiting = NULL;
1556
1557 /* unlock addr mutex */
1558
1559 while (next) {
1560 ctx = next;
1561 ctx->state = NGX_OK;
1562 ctx->name = name;
1563 next = ctx->next;
1564
1565 ctx->handler(ctx);
1566 }
1567
1568 ngx_resolver_free(r, name.data);
1569
1570 return;
1571
1572 invalid_in_addr_arpa:
1573
1574 ngx_log_error(r->log_level, r->log, 0,
1575 "invalid in-addr.arpa name in DNS response");
1576 return;
1577
1578 short_response:
1579
1580 err = "short DNS response";
1581
1582 invalid:
1583
1584 /* unlock addr mutex */
1585
1586 ngx_log_error(r->log_level, r->log, 0, err);
1587
1588 return;
1589
1590 failed:
1591
1592 /* unlock addr mutex */
1593
1594 return;
1595 }
1596
1597
1598 static ngx_resolver_node_t *
1599 ngx_resolver_lookup_name(ngx_resolver_t *r, ngx_str_t *name, uint32_t hash)
1600 {
1601 ngx_int_t rc;
1602 ngx_rbtree_node_t *node, *sentinel;
1603 ngx_resolver_node_t *rn;
1604
1605 node = r->name_rbtree.root;
1606 sentinel = r->name_rbtree.sentinel;
1607
1608 while (node != sentinel) {
1609
1610 if (hash < node->key) {
1611 node = node->left;
1612 continue;
1613 }
1614
1615 if (hash > node->key) {
1616 node = node->right;
1617 continue;
1618 }
1619
1620 /* hash == node->key */
1621
1622 do {
1623 rn = (ngx_resolver_node_t *) node;
1624
1625 rc = ngx_memn2cmp(name->data, rn->name, name->len, rn->nlen);
1626
1627 if (rc == 0) {
1628 return rn;
1629 }
1630
1631 node = (rc < 0) ? node->left : node->right;
1632
1633 } while (node != sentinel && hash == node->key);
1634
1635 break;
1636 }
1637
1638 /* not found */
1639
1640 return NULL;
1641 }
1642
1643
1644 static ngx_resolver_node_t *
1645 ngx_resolver_lookup_addr(ngx_resolver_t *r, in_addr_t addr)
1646 {
1647 ngx_rbtree_node_t *node, *sentinel;
1648
1649 node = r->addr_rbtree.root;
1650 sentinel = r->addr_rbtree.sentinel;
1651
1652 while (node != sentinel) {
1653
1654 if (addr < node->key) {
1655 node = node->left;
1656 continue;
1657 }
1658
1659 if (addr > node->key) {
1660 node = node->right;
1661 continue;
1662 }
1663
1664 /* addr == node->key */
1665
1666 return (ngx_resolver_node_t *) node;
1667 }
1668
1669 /* not found */
1670
1671 return NULL;
1672 }
1673
1674
1675 static void
1676 ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
1677 ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
1678 {
1679 ngx_rbtree_node_t **p;
1680 ngx_resolver_node_t *rn, *rn_temp;
1681
1682 for ( ;; ) {
1683
1684 if (node->key < temp->key) {
1685
1686 p = &temp->left;
1687
1688 } else if (node->key > temp->key) {
1689
1690 p = &temp->right;
1691
1692 } else { /* node->key == temp->key */
1693
1694 rn = (ngx_resolver_node_t *) node;
1695 rn_temp = (ngx_resolver_node_t *) temp;
1696
1697 p = (ngx_memn2cmp(rn->name, rn_temp->name, rn->nlen, rn_temp->nlen)
1698 < 0) ? &temp->left : &temp->right;
1699 }
1700
1701 if (*p == sentinel) {
1702 break;
1703 }
1704
1705 temp = *p;
1706 }
1707
1708 *p = node;
1709 node->parent = temp;
1710 node->left = sentinel;
1711 node->right = sentinel;
1712 ngx_rbt_red(node);
1713 }
1714
1715
1716 static ngx_int_t
1717 ngx_resolver_create_name_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
1718 {
1719 u_char *p, *s;
1720 size_t len;
1721 ngx_uint_t ident;
1722 ngx_resolver_qs_t *qs;
1723 ngx_resolver_query_t *query;
1724
1725 len = sizeof(ngx_resolver_query_t)
1726 + 1 + ctx->name.len + 1 + sizeof(ngx_resolver_qs_t);
1727
1728 p = ngx_resolver_calloc(ctx->resolver, len);
1729 if (p == NULL) {
1730 return NGX_ERROR;
1731 }
1732
1733 rn->qlen = (u_short) len;
1734 rn->query = p;
1735
1736 query = (ngx_resolver_query_t *) p;
1737
1738 ident = ngx_random();
1739
1740 ngx_log_debug2(NGX_LOG_DEBUG_CORE, ctx->resolver->log, 0,
1741 "resolve: \"%V\" %i", &ctx->name, ident & 0xffff);
1742
1743 query->ident_hi = (u_char) ((ident >> 8) & 0xff);
1744 query->ident_lo = (u_char) (ident & 0xff);
1745
1746 /* recursion query */
1747 query->flags_hi = 1; query->flags_lo = 0;
1748
1749 /* one question */
1750 query->nqs_hi = 0; query->nqs_lo = 1;
1751 query->nan_hi = 0; query->nan_lo = 0;
1752 query->nns_hi = 0; query->nns_lo = 0;
1753 query->nar_hi = 0; query->nar_lo = 0;
1754
1755 p += sizeof(ngx_resolver_query_t) + 1 + ctx->name.len + 1;
1756
1757 qs = (ngx_resolver_qs_t *) p;
1758
1759 /* query type */
1760 qs->type_hi = 0; qs->type_lo = (u_char) ctx->type;
1761
1762 /* IP query class */
1763 qs->class_hi = 0; qs->class_lo = 1;
1764
1765 /* convert "www.example.com" to "\3www\7example\3com\0" */
1766
1767 len = 0;
1768 p--;
1769 *p-- = '\0';
1770
1771 for (s = ctx->name.data + ctx->name.len - 1; s >= ctx->name.data; s--) {
1772 if (*s != '.') {
1773 *p = *s;
1774 len++;
1775
1776 } else {
1777 if (len == 0) {
1778 return NGX_DECLINED;
1779 }
1780
1781 *p = (u_char) len;
1782 len = 0;
1783 }
1784
1785 p--;
1786 }
1787
1788 *p = (u_char) len;
1789
1790 return NGX_OK;
1791 }
1792
1793
1794 /* AF_INET only */
1795
1796 static ngx_int_t
1797 ngx_resolver_create_addr_query(ngx_resolver_node_t *rn, ngx_resolver_ctx_t *ctx)
1798 {
1799 u_char *p, *d;
1800 size_t len;
1801 ngx_int_t n;
1802 ngx_uint_t ident;
1803 ngx_resolver_query_t *query;
1804
1805 len = sizeof(ngx_resolver_query_t)
1806 + sizeof(".255.255.255.255.in-addr.arpa.") - 1
1807 + sizeof(ngx_resolver_qs_t);
1808
1809 p = ngx_resolver_calloc(ctx->resolver, len);
1810 if (p == NULL) {
1811 return NGX_ERROR;
1812 }
1813
1814 rn->query = p;
1815 query = (ngx_resolver_query_t *) p;
1816
1817 ident = ngx_random();
1818
1819 query->ident_hi = (u_char) ((ident >> 8) & 0xff);
1820 query->ident_lo = (u_char) (ident & 0xff);
1821
1822 /* recursion query */
1823 query->flags_hi = 1; query->flags_lo = 0;
1824
1825 /* one question */
1826 query->nqs_hi = 0; query->nqs_lo = 1;
1827 query->nan_hi = 0; query->nan_lo = 0;
1828 query->nns_hi = 0; query->nns_lo = 0;
1829 query->nar_hi = 0; query->nar_lo = 0;
1830
1831 p += sizeof(ngx_resolver_query_t);
1832
1833 for (n = 0; n < 32; n += 8){
1834 d = ngx_sprintf(&p[1], "%ud", (ctx->addr >> n) & 0xff);
1835 *p = (u_char) (d - &p[1]);
1836 p = d;
1837 }
1838
1839 /* query type "PTR", IP query class */
1840 ngx_memcpy(p, "\7in-addr\4arpa\0\0\14\0\1", 18);
1841
1842 rn->qlen = (u_short)
1843 (p + sizeof("\7in-addr\4arpa") + sizeof(ngx_resolver_qs_t)
1844 - rn->query);
1845
1846 return NGX_OK;
1847 }
1848
1849
1850 static ngx_int_t
1851 ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name, u_char *buf, u_char *src,
1852 u_char *last)
1853 {
1854 char *err;
1855 u_char *p, *dst;
1856 ssize_t len;
1857 ngx_uint_t i, n;
1858
1859 p = src;
1860 len = -1;
1861
1862 /*
1863 * compression pointers allow to create endless loop, so we set limit;
1864 * 128 pointers should be enough to store 255-byte name
1865 */
1866
1867 for (i = 0; i < 128; i++) {
1868 n = *p++;
1869
1870 if (n == 0) {
1871 goto done;
1872 }
1873
1874 if (n & 0xc0) {
1875 n = ((n & 0x3f) << 8) + *p;
1876 p = &buf[n];
1877
1878 } else {
1879 len += 1 + n;
1880 p = &p[n];
1881 }
1882
1883 if (p >= last) {
1884 err = "name is out of response";
1885 goto invalid;
1886 }
1887 }
1888
1889 err = "compression pointers loop";
1890
1891 invalid:
1892
1893 ngx_log_error(r->log_level, r->log, 0, err);
1894
1895 return NGX_ERROR;
1896
1897 done:
1898
1899 if (name == NULL) {
1900 return NGX_OK;
1901 }
1902
1903 dst = ngx_resolver_alloc(r, len);
1904 if (dst == NULL) {
1905 return NGX_ERROR;
1906 }
1907
1908 name->data = dst;
1909
1910 n = *src++;
1911
1912 for ( ;; ) {
1913 if (n != 0xc0) {
1914 ngx_memcpy(dst, src, n);
1915 dst += n;
1916 src += n;
1917
1918 n = *src++;
1919
1920 if (n != 0) {
1921 *dst++ = '.';
1922 }
1923
1924 } else {
1925 n = ((n & 0x3f) << 8) + *src;
1926 src = &buf[n];
1927
1928 n = *src++;
1929 }
1930
1931 if (n == 0) {
1932 name->len = dst - name->data;
1933 return NGX_OK;
1934 }
1935 }
1936 }
1937
1938
1939 static void
1940 ngx_resolver_timeout_handler(ngx_event_t *ev)
1941 {
1942 ngx_resolver_ctx_t *ctx;
1943
1944 ctx = ev->data;
1945
1946 ctx->state = NGX_RESOLVE_TIMEDOUT;
1947
1948 ctx->handler(ctx);
1949 }
1950
1951
1952 static void
1953 ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn)
1954 {
1955 /* lock alloc mutex */
1956
1957 if (rn->query) {
1958 ngx_resolver_free_locked(r, rn->query);
1959 }
1960
1961 if (rn->name) {
1962 ngx_resolver_free_locked(r, rn->name);
1963 }
1964
1965 if (rn->cnlen) {
1966 ngx_resolver_free_locked(r, rn->u.cname);
1967 }
1968
1969 if (rn->naddrs > 1) {
1970 ngx_resolver_free_locked(r, rn->u.addrs);
1971 }
1972
1973 ngx_resolver_free_locked(r, rn);
1974
1975 /* unlock alloc mutex */
1976 }
1977
1978
1979 static void *
1980 ngx_resolver_alloc(ngx_resolver_t *r, size_t size)
1981 {
1982 u_char *p;
1983
1984 /* lock alloc mutex */
1985
1986 p = ngx_alloc(size, r->log);
1987
1988 /* unlock alloc mutex */
1989
1990 return p;
1991 }
1992
1993
1994 static void *
1995 ngx_resolver_calloc(ngx_resolver_t *r, size_t size)
1996 {
1997 u_char *p;
1998
1999 p = ngx_resolver_alloc(r, size);
2000
2001 if (p) {
2002 ngx_memzero(p, size);
2003 }
2004
2005 return p;
2006 }
2007
2008
2009 static void
2010 ngx_resolver_free(ngx_resolver_t *r, void *p)
2011 {
2012 /* lock alloc mutex */
2013
2014 ngx_free(p);
2015
2016 /* unlock alloc mutex */
2017 }
2018
2019
2020 static void
2021 ngx_resolver_free_locked(ngx_resolver_t *r, void *p)
2022 {
2023 ngx_free(p);
2024 }
2025
2026
2027 static void *
2028 ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size)
2029 {
2030 void *dst;
2031
2032 dst = ngx_resolver_alloc(r, size);
2033
2034 if (dst == NULL) {
2035 return dst;
2036 }
2037
2038 ngx_memcpy(dst, src, size);
2039
2040 return dst;
2041 }
2042
2043
2044 char *
2045 ngx_resolver_strerror(ngx_int_t err)
2046 {
2047 static char *errors[] = {
2048 "Format error", /* FORMERR */
2049 "Server failure", /* SERVFAIL */
2050 "Host not found", /* NXDOMAIN */
2051 "Unimplemented", /* NOTIMP */
2052 "Operation refused" /* REFUSED */
2053 };
2054
2055 if (err > 0 && err < 6) {
2056 return errors[err - 1];
2057 }
2058
2059 if (err == NGX_RESOLVE_TIMEDOUT) {
2060 return "Operation timed out";
2061 }
2062
2063 return "Unknown error";
2064 }
2065
2066
2067 ngx_int_t
2068 ngx_udp_connect(ngx_udp_connection_t *uc)
2069 {
2070 int rc;
2071 ngx_int_t event;
2072 ngx_event_t *rev, *wev;
2073 ngx_socket_t s;
2074 ngx_connection_t *c;
2075
2076 s = ngx_socket(AF_INET, SOCK_DGRAM, 0);
2077
2078 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, uc->log, 0, "UDP socket %d", s);
2079
2080 if (s == -1) {
2081 ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
2082 ngx_socket_n " failed");
2083 return NGX_ERROR;
2084 }
2085
2086 c = ngx_get_connection(s, uc->log);
2087
2088 if (c == NULL) {
2089 if (ngx_close_socket(s) == -1) {
2090 ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
2091 ngx_close_socket_n "failed");
2092 }
2093
2094 return NGX_ERROR;
2095 }
2096
2097 if (ngx_nonblocking(s) == -1) {
2098 ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
2099 ngx_nonblocking_n " failed");
2100
2101 ngx_free_connection(c);
2102
2103 if (ngx_close_socket(s) == -1) {
2104 ngx_log_error(NGX_LOG_ALERT, uc->log, ngx_socket_errno,
2105 ngx_close_socket_n " failed");
2106 }
2107
2108 return NGX_ERROR;
2109 }
2110
2111 rev = c->read;
2112 wev = c->write;
2113
2114 rev->log = uc->log;
2115 wev->log = uc->log;
2116
2117 uc->connection = c;
2118
2119 c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);
2120
2121 #if (NGX_THREADS)
2122
2123 /* TODO: lock event when call completion handler */
2124
2125 rev->lock = &c->lock;
2126 wev->lock = &c->lock;
2127 rev->own_lock = &c->lock;
2128 wev->own_lock = &c->lock;
2129
2130 #endif
2131
2132 ngx_log_debug3(NGX_LOG_DEBUG_EVENT, uc->log, 0,
2133 "connect to %V, fd:%d #%d", &uc->server, s, c->number);
2134
2135 rc = connect(s, uc->sockaddr, uc->socklen);
2136
2137 /* TODO: aio, iocp */
2138
2139 if (rc == -1) {
2140 ngx_log_error(NGX_LOG_CRIT, uc->log, ngx_socket_errno,
2141 "connect() to %V failed", &uc->server);
2142
2143 return NGX_ERROR;
2144 }
2145
2146 /* UDP sockets are always ready to write */
2147 wev->ready = 1;
2148
2149 if (ngx_add_event) {
2150
2151 event = (ngx_event_flags & NGX_USE_CLEAR_EVENT) ?
2152 /* kqueue, epoll */ NGX_CLEAR_EVENT:
2153 /* select, poll, /dev/poll */ NGX_LEVEL_EVENT;
2154 /* eventport event type has no meaning: oneshot only */
2155
2156 if (ngx_add_event(rev, NGX_READ_EVENT, event) != NGX_OK) {
2157 return NGX_ERROR;
2158 }
2159
2160 } else {
2161 /* rtsig */
2162
2163 if (ngx_add_conn(c) == NGX_ERROR) {
2164 return NGX_ERROR;
2165 }
2166 }
2167
2168 return NGX_OK;
2169 }
2170
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