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 ngx_int_t ngx_resolve_name_locked(ngx_resolver_t *r,
54 ngx_resolver_ctx_t *ctx);
55 static void ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree,
56 ngx_queue_t *queue);
57 static ngx_int_t ngx_resolver_send_query(ngx_resolver_t *r,
58 ngx_resolver_node_t *rn);
59 static ngx_int_t ngx_resolver_create_name_query(ngx_resolver_node_t *rn,
60 ngx_resolver_ctx_t *ctx);
61 static ngx_int_t ngx_resolver_create_addr_query(ngx_resolver_node_t *rn,
62 ngx_resolver_ctx_t *ctx);
63 static void ngx_resolver_resend_handler(ngx_event_t *ev);
64 static time_t ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree,
65 ngx_queue_t *queue);
66 static void ngx_resolver_read_response(ngx_event_t *rev);
67 static void ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf,
68 size_t n);
69 static void ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t n,
70 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans);
71 static void ngx_resolver_process_ptr(ngx_resolver_t *r, u_char *buf, size_t n,
72 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan);
73 static ngx_resolver_node_t *ngx_resolver_lookup_name(ngx_resolver_t *r,
74 ngx_str_t *name, uint32_t hash);
75 static ngx_resolver_node_t *ngx_resolver_lookup_addr(ngx_resolver_t *r,
76 in_addr_t addr);
77 static void ngx_resolver_rbtree_insert_value(ngx_rbtree_node_t *temp,
78 ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
79 static ngx_int_t ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name,
80 u_char *buf, u_char *src, u_char *last);
81 static void ngx_resolver_timeout_handler(ngx_event_t *ev);
82 static void ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn);
83 static void *ngx_resolver_alloc(ngx_resolver_t *r, size_t size);
84 static void ngx_resolver_free(ngx_resolver_t *r, void *p);
85 static void ngx_resolver_free_locked(ngx_resolver_t *r, void *p);
86 static void *ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size);
87
88
89 /* STUB: ngx_peer_addr_t * */
90
91 ngx_resolver_t *
92 ngx_resolver_create(ngx_peer_addr_t *addr, ngx_log_t *log)
93 {
94 ngx_resolver_t *r;
95 ngx_udp_connection_t *uc;
96
97 r = ngx_calloc(sizeof(ngx_resolver_t), log);
98 if (r == NULL) {
99 return NULL;
100 }
101
102 r->event = ngx_calloc(sizeof(ngx_event_t), log);
103 if (r->event == NULL) {
104 return NULL;
105 }
106
107 ngx_rbtree_init(&r->name_rbtree, &r->name_sentinel,
108 ngx_resolver_rbtree_insert_value);
109
110 ngx_rbtree_init(&r->addr_rbtree, &r->addr_sentinel,
111 ngx_rbtree_insert_value);
112
113 ngx_queue_init(&r->name_resend_queue);
114 ngx_queue_init(&r->addr_resend_queue);
115
116 ngx_queue_init(&r->name_expire_queue);
117 ngx_queue_init(&r->addr_expire_queue);
118
119 r->event->handler = ngx_resolver_resend_handler;
120 r->event->data = r;
121 r->event->log = log;
122 r->ident = -1;
123
124 r->resend_timeout = 5;
125 r->expire = 30;
126 r->valid = 300;
127
128 r->log = log;
129 r->log_level = NGX_LOG_ALERT;
130
131 if (addr) {
132 uc = ngx_calloc(sizeof(ngx_udp_connection_t), log);
133 if (uc == NULL) {
134 return NULL;
135 }
136
137 r->udp_connection = uc;
138
139 uc->sockaddr = addr->sockaddr;
140 uc->socklen = addr->socklen;
141 uc->server = addr->name;
142 uc->log = log;
143 }
144
145 return r;
146 }
147
148
149 ngx_resolver_ctx_t *
150 ngx_resolve_start(ngx_resolver_t *r, ngx_resolver_ctx_t *temp)
151 {
152 in_addr_t addr;
153 ngx_resolver_ctx_t *ctx;
154
155 if (temp) {
156 addr = ngx_inet_addr(temp->name.data, temp->name.len);
157
158 if (addr != INADDR_NONE) {
159 temp->resolver = r;
160 temp->state = NGX_OK;
161 temp->naddrs = 1;
162 temp->addrs = &temp->addr;
163 temp->addr = addr;
164 temp->quick = 1;
165
166 return temp;
167 }
168 }
169
170 if (r->udp_connection == NULL) {
171 return NGX_NO_RESOLVER;
172 }
173
174 ctx = ngx_resolver_calloc(r, sizeof(ngx_resolver_ctx_t));
175
176 if (ctx) {
177 ctx->resolver = r;
178 }
179
180 return ctx;
181 }
182
183
184 ngx_int_t
185 ngx_resolve_name(ngx_resolver_ctx_t *ctx)
186 {
187 ngx_int_t rc;
188 ngx_resolver_t *r;
189
190 r = ctx->resolver;
191
192 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
193 "resolve: \"%V\"", &ctx->name);
194
195 if (ctx->quick) {
196 ctx->handler(ctx);
197 return NGX_OK;
198 }
199
200 /* lock name mutex */
201
202 rc = ngx_resolve_name_locked(r, ctx);
203
204 if (rc == NGX_OK) {
205 return NGX_OK;
206 }
207
208 /* unlock name mutex */
209
210 if (rc == NGX_AGAIN) {
211 return NGX_OK;
212 }
213
214 /* lock alloc mutex */
215
216 if (ctx->event) {
217 ngx_resolver_free_locked(r, ctx->event);
218 ctx->event = NULL;
219 }
220
221 /* unlock alloc mutex */
222
223 return NGX_ERROR;
224 }
225
226
227 void
228 ngx_resolve_name_done(ngx_resolver_ctx_t *ctx)
229 {
230 uint32_t hash;
231 ngx_resolver_t *r;
232 ngx_resolver_ctx_t *w, **p;
233 ngx_resolver_node_t *rn;
234
235 r = ctx->resolver;
236
237 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
238 "resolve name done: %i", ctx->state);
239
240 if (ctx->quick) {
241 return;
242 }
243
244 if (ctx->event && ctx->event->timer_set) {
245 ngx_del_timer(ctx->event);
246 }
247
248 /* lock name mutex */
249
250 if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
251
252 hash = ngx_crc32_short(ctx->name.data, ctx->name.len);
253
254 rn = ngx_resolver_lookup_name(r, &ctx->name, hash);
255
256 if (rn) {
257 p = &rn->waiting;
258 w = rn->waiting;
259
260 while (w) {
261 if (w == ctx) {
262 *p = w->next;
263
264 goto done;
265 }
266
267 p = &w->next;
268 w = w->next;
269 }
270 }
271
272 ngx_log_error(NGX_LOG_ALERT, r->log, 0,
273 "could not cancel %V resolving", &ctx->name);
274 }
275
276 done:
277
278 ngx_resolver_expire(r, &r->name_rbtree, &r->name_expire_queue);
279
280 /* unlock name mutex */
281
282 ngx_resolver_free(r, ctx);
283 }
284
285
286 /* NGX_RESOLVE_A only */
287
288 static ngx_int_t
289 ngx_resolve_name_locked(ngx_resolver_t *r, ngx_resolver_ctx_t *ctx)
290 {
291 uint32_t hash;
292 in_addr_t addr, *addrs;
293 ngx_uint_t naddrs;
294 ngx_resolver_ctx_t *next;
295 ngx_resolver_node_t *rn;
296
297 hash = ngx_crc32_short(ctx->name.data, ctx->name.len);
298
299 rn = ngx_resolver_lookup_name(r, &ctx->name, hash);
300
301 if (rn) {
302
303 if (rn->valid >= ngx_time()) {
304
305 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached");
306
307 ngx_queue_remove(&rn->queue);
308
309 rn->expire = ngx_time() + r->expire;
310
311 ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
312
313 naddrs = rn->naddrs;
314
315 if (naddrs) {
316
317 /* NGX_RESOLVE_A answer */
318
319 if (naddrs != 1) {
320 addr = 0;
321 addrs = ngx_resolver_dup(r, rn->u.addrs,
322 naddrs * sizeof(in_addr_t));
323 if (addrs == NULL) {
324 return NGX_ERROR;
325 }
326
327 } else {
328 addr = rn->u.addr;
329 addrs = NULL;
330 }
331
332 ctx->next = rn->waiting;
333 rn->waiting = NULL;
334
335 /* unlock name mutex */
336
337 do {
338 ctx->state = NGX_OK;
339 ctx->naddrs = naddrs;
340 ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs;
341 ctx->addr = addr;
342 next = ctx->next;
343
344 ctx->handler(ctx);
345
346 ctx = next;
347 } while (ctx);
348
349 if (addrs) {
350 ngx_resolver_free(r, addrs);
351 }
352
353 return NGX_OK;
354 }
355
356 /* NGX_RESOLVE_CNAME */
357
358 ctx->name.len = rn->cnlen;
359 ctx->name.data = rn->u.cname;
360
361 return ngx_resolve_name_locked(r, ctx);
362 }
363
364 if (rn->waiting) {
365
366 ctx->next = rn->waiting;
367 rn->waiting = ctx;
368
369 return NGX_AGAIN;
370 }
371
372 ngx_queue_remove(&rn->queue);
373
374 /* lock alloc mutex */
375
376 ngx_resolver_free_locked(r, rn->query);
377
378 if (rn->cnlen) {
379 ngx_resolver_free_locked(r, rn->u.cname);
380 }
381
382 if (rn->naddrs > 1) {
383 ngx_resolver_free_locked(r, rn->u.addrs);
384 }
385
386 /* unlock alloc mutex */
387
388 } else {
389
390 rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
391 if (rn == NULL) {
392 return NGX_ERROR;
393 }
394
395 rn->name = ngx_resolver_dup(r, ctx->name.data, ctx->name.len);
396 if (rn->name == NULL) {
397 ngx_resolver_free(r, rn);
398 return NGX_ERROR;
399 }
400
401 rn->node.key = hash;
402 rn->nlen = (u_short) ctx->name.len;
403
404 ngx_rbtree_insert(&r->name_rbtree, &rn->node);
405 }
406
407 if (ngx_resolver_create_name_query(rn, ctx) != NGX_OK) {
408 goto failed;
409 }
410
411 if (ngx_resolver_send_query(r, rn) != NGX_OK) {
412 goto failed;
413 }
414
415 if (ctx->event == NULL) {
416 ctx->event = ngx_resolver_calloc(r, sizeof(ngx_event_t));
417 if (ctx->event == NULL) {
418 goto failed;
419 }
420
421 ctx->event->handler = ngx_resolver_timeout_handler;
422 ctx->event->data = ctx;
423 ctx->event->log = r->log;
424 ctx->ident = -1;
425
426 ngx_add_timer(ctx->event, ctx->timeout);
427 }
428
429 if (ngx_queue_empty(&r->name_resend_queue)) {
430 ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
431 }
432
433 rn->expire = ngx_time() + r->resend_timeout;
434
435 ngx_queue_insert_head(&r->name_resend_queue, &rn->queue);
436
437 rn->cnlen = 0;
438 rn->naddrs = 0;
439 rn->valid = 0;
440 rn->waiting = ctx;
441
442 ctx->state = NGX_AGAIN;
443
444 return NGX_AGAIN;
445
446 failed:
447
448 ngx_rbtree_delete(&r->name_rbtree, &rn->node);
449
450 ngx_resolver_free(r, rn->name);
451
452 ngx_resolver_free(r, rn);
453
454 return NGX_ERROR;
455 }
456
457
458 ngx_int_t
459 ngx_resolve_addr(ngx_resolver_ctx_t *ctx)
460 {
461 ngx_resolver_t *r;
462 ngx_resolver_node_t *rn;
463
464 r = ctx->resolver;
465
466 ctx->addr = ntohl(ctx->addr);
467
468 /* lock addr mutex */
469
470 rn = ngx_resolver_lookup_addr(r, ctx->addr);
471
472 if (rn) {
473
474 if (rn->valid >= ngx_time()) {
475
476 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolve cached");
477
478 ngx_queue_remove(&rn->queue);
479
480 rn->expire = ngx_time() + r->expire;
481
482 ngx_queue_insert_head(&r->addr_expire_queue, &rn->queue);
483
484 ctx->name.len = rn->nlen;
485 ctx->name.data = ngx_resolver_dup(r, rn->name, rn->nlen);
486 if (ctx->name.data == NULL) {
487 goto failed;
488 }
489
490 /* unlock addr mutex */
491
492 ctx->state = NGX_OK;
493
494 ctx->handler(ctx);
495
496 ngx_resolver_free(r, ctx->name.data);
497
498 return NGX_OK;
499 }
500
501 if (rn->waiting) {
502
503 ctx->next = rn->waiting;
504 rn->waiting = ctx;
505
506 return NGX_AGAIN;
507 }
508
509 ngx_queue_remove(&rn->queue);
510
511 ngx_resolver_free(r, rn->query);
512
513 } else {
514 rn = ngx_resolver_alloc(r, sizeof(ngx_resolver_node_t));
515 if (rn == NULL) {
516 goto failed;
517 }
518
519 rn->node.key = ctx->addr;
520
521 ngx_rbtree_insert(&r->addr_rbtree, &rn->node);
522 }
523
524 if (ngx_resolver_create_addr_query(rn, ctx) != NGX_OK) {
525 goto failed;
526 }
527
528 if (ngx_resolver_send_query(r, rn) != NGX_OK) {
529 goto failed;
530 }
531
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 if (ngx_queue_empty(&r->addr_resend_queue)) {
545 ngx_add_timer(r->event, (ngx_msec_t) (r->resend_timeout * 1000));
546 }
547
548 rn->expire = ngx_time() + r->resend_timeout;
549
550 ngx_queue_insert_head(&r->addr_resend_queue, &rn->queue);
551
552 rn->cnlen = 0;
553 rn->naddrs = 0;
554 rn->name = NULL;
555 rn->nlen = 0;
556 rn->valid = 0;
557 rn->waiting = ctx;
558
559 /* unlock addr mutex */
560
561 ctx->state = NGX_AGAIN;
562
563 return NGX_OK;
564
565 failed:
566
567 if (rn) {
568 ngx_rbtree_delete(&r->addr_rbtree, &rn->node);
569
570 ngx_resolver_free(r, rn);
571 }
572
573 /* unlock addr mutex */
574
575 /* lock alloc mutex */
576
577 if (ctx->event) {
578 ngx_resolver_free_locked(r, ctx->event);
579 }
580
581 ngx_resolver_free_locked(r, ctx);
582
583 /* unlock alloc mutex */
584
585 return NGX_ERROR;
586 }
587
588
589 void
590 ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx)
591 {
592 in_addr_t addr;
593 ngx_resolver_t *r;
594 ngx_resolver_ctx_t *w, **p;
595 ngx_resolver_node_t *rn;
596
597 r = ctx->resolver;
598
599 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
600 "resolve addr done: %i", ctx->state);
601
602 if (ctx->event && ctx->event->timer_set) {
603 ngx_del_timer(ctx->event);
604 }
605
606 /* lock addr mutex */
607
608 if (ctx->state == NGX_AGAIN || ctx->state == NGX_RESOLVE_TIMEDOUT) {
609
610 rn = ngx_resolver_lookup_addr(r, ctx->addr);
611
612 if (rn) {
613 p = &rn->waiting;
614 w = rn->waiting;
615
616 while (w) {
617 if (w == ctx) {
618 *p = w->next;
619
620 goto done;
621 }
622
623 p = &w->next;
624 w = w->next;
625 }
626 }
627
628 addr = ntohl(ctx->addr);
629
630 ngx_log_error(NGX_LOG_ALERT, r->log, 0,
631 "could not cancel %ud.%ud.%ud.%ud resolving",
632 (addr >> 24) & 0xff, (addr >> 16) & 0xff,
633 (addr >> 8) & 0xff, addr & 0xff);
634 }
635
636 done:
637
638 ngx_resolver_expire(r, &r->addr_rbtree, &r->addr_expire_queue);
639
640 /* unlock addr mutex */
641
642 ngx_resolver_free(r, ctx);
643 }
644
645
646 static void
647 ngx_resolver_expire(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue)
648 {
649 time_t now;
650 ngx_uint_t i;
651 ngx_queue_t *q;
652 ngx_resolver_node_t *rn;
653
654 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver expire");
655
656 now = ngx_time();
657
658 for (i = 0; i < 2; i++) {
659 if (ngx_queue_empty(queue)) {
660 return;
661 }
662
663 q = ngx_queue_last(queue);
664
665 rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
666
667 if (now <= rn->expire) {
668 return;
669 }
670
671 ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
672 "resolver expire \"%*s\"", (size_t) rn->nlen, rn->name);
673
674 ngx_queue_remove(q);
675
676 ngx_rbtree_delete(tree, &rn->node);
677
678 ngx_resolver_free_node(r, rn);
679 }
680 }
681
682
683 static ngx_int_t
684 ngx_resolver_send_query(ngx_resolver_t *r, ngx_resolver_node_t *rn)
685 {
686 ssize_t n;
687 ngx_udp_connection_t *uc;
688
689 uc = r->udp_connection;
690
691 if (uc->connection == NULL) {
692 if (ngx_udp_connect(uc) != NGX_OK) {
693 return NGX_ERROR;
694 }
695
696 uc->connection->data = r;
697 uc->connection->read->handler = ngx_resolver_read_response;
698 }
699
700 n = ngx_send(uc->connection, rn->query, rn->qlen);
701
702 if (n == -1) {
703 return NGX_ERROR;
704 }
705
706 if ((size_t) n != (size_t) rn->qlen) {
707 ngx_log_error(NGX_LOG_CRIT, uc->log, 0, "send() incomplete");
708 return NGX_ERROR;
709 }
710
711 return NGX_OK;
712 }
713
714
715 static void
716 ngx_resolver_resend_handler(ngx_event_t *ev)
717 {
718 time_t timer, atimer, ntimer;
719 ngx_resolver_t *r;
720
721 r = ev->data;
722
723 ngx_log_debug0(NGX_LOG_DEBUG_CORE, r->log, 0,
724 "resolver resend handler");
725
726 /* lock name mutex */
727
728 ntimer = ngx_resolver_resend(r, &r->name_rbtree, &r->name_resend_queue);
729
730 /* unlock name mutex */
731
732 /* lock addr mutex */
733
734 atimer = ngx_resolver_resend(r, &r->addr_rbtree, &r->addr_resend_queue);
735
736 /* unlock addr mutex */
737
738 if (ntimer == 0) {
739 timer = atimer;
740
741 } else if (atimer == 0) {
742 timer = ntimer;
743
744 } else {
745 timer = (atimer < ntimer) ? atimer : ntimer;
746 }
747
748 if (timer) {
749 ngx_add_timer(r->event, (ngx_msec_t) (timer * 1000));
750 }
751 }
752
753
754 static time_t
755 ngx_resolver_resend(ngx_resolver_t *r, ngx_rbtree_t *tree, ngx_queue_t *queue)
756 {
757 time_t now;
758 ngx_queue_t *q;
759 ngx_resolver_node_t *rn;
760
761 now = ngx_time();
762
763 for ( ;; ) {
764 if (ngx_queue_empty(queue)) {
765 return 0;
766 }
767
768 q = ngx_queue_last(queue);
769
770 rn = ngx_queue_data(q, ngx_resolver_node_t, queue);
771
772 if (now < rn->expire) {
773 return rn->expire - now;
774 }
775
776 ngx_log_debug3(NGX_LOG_DEBUG_CORE, r->log, 0,
777 "resolver resend \"%*s\" %p",
778 (size_t) rn->nlen, rn->name, rn->waiting);
779
780 ngx_queue_remove(q);
781
782 if (rn->waiting) {
783
784 if (ngx_resolver_send_query(r, rn) == NGX_OK) {
785
786 rn->expire = now + r->resend_timeout;
787
788 ngx_queue_insert_head(queue, &rn->queue);
789 }
790
791 continue;
792 }
793
794 ngx_rbtree_delete(tree, &rn->node);
795
796 ngx_resolver_free_node(r, rn);
797 }
798 }
799
800
801 static void
802 ngx_resolver_read_response(ngx_event_t *rev)
803 {
804 ssize_t n;
805 ngx_connection_t *c;
806 u_char buf[NGX_RESOLVER_UDP_SIZE];
807
808 c = rev->data;
809
810 do {
811 n = ngx_udp_recv(c, buf, NGX_RESOLVER_UDP_SIZE);
812
813 if (n < 0) {
814 return;
815 }
816
817 ngx_resolver_process_response(c->data, buf, n);
818
819 } while (rev->ready);
820 }
821
822
823 static void
824 ngx_resolver_process_response(ngx_resolver_t *r, u_char *buf, size_t n)
825 {
826 char *err;
827 size_t len;
828 ngx_uint_t i, ident, flags, code, nqs, nan, qtype, qclass;
829 ngx_resolver_qs_t *qs;
830 ngx_resolver_query_t *query;
831
832 if ((size_t) n < sizeof(ngx_resolver_query_t) + 1) {
833 goto short_response;
834 }
835
836 query = (ngx_resolver_query_t *) buf;
837
838 ident = (query->ident_hi << 8) + query->ident_lo;
839 flags = (query->flags_hi << 8) + query->flags_lo;
840 nqs = (query->nqs_hi << 8) + query->nqs_lo;
841 nan = (query->nan_hi << 8) + query->nan_lo;
842
843 ngx_log_debug6(NGX_LOG_DEBUG_CORE, r->log, 0,
844 "resolver DNS response %d fl:%04Xud %d/%d/%d/%d",
845 ident, flags, nqs, nan,
846 (query->nns_hi << 8) + query->nns_lo,
847 (query->nar_hi << 8) + query->nar_lo);
848
849 if (!(flags & 0x8000)) {
850 ngx_log_error(r->log_level, r->log, 0,
851 "invalid DNS response %d fl:%04Xud", ident, flags);
852 return;
853 }
854
855 code = flags & 0x7f;
856
857 if (code == NGX_RESOLVE_FORMERR || code > NGX_RESOLVE_REFUSED) {
858 ngx_log_error(r->log_level, r->log, 0,
859 "DNS error (%d: %s), query id:%d",
860 code, ngx_resolver_strerror(code), ident);
861 return;
862 }
863
864 if (nqs != 1) {
865 err = "invalid number of questions in DNS response";
866 goto done;
867 }
868
869 i = sizeof(ngx_resolver_query_t);
870
871 while (i < (ngx_uint_t) n) {
872 if (buf[i] == '\0') {
873 goto found;
874 }
875
876 len = buf[i];
877 i += 1 + len;
878 }
879
880 goto short_response;
881
882 found:
883
884 if (i++ == 0) {
885 err = "zero-length domain name in DNS response";
886 goto done;
887 }
888
889 if (i + sizeof(ngx_resolver_qs_t) + nan * (2 + sizeof(ngx_resolver_an_t))
890 > (ngx_uint_t) n)
891 {
892 goto short_response;
893 }
894
895 qs = (ngx_resolver_qs_t *) &buf[i];
896
897 qtype = (qs->type_hi << 8) + qs->type_lo;
898 qclass = (qs->class_hi << 8) + qs->class_lo;
899
900 ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
901 "resolver DNS response qt:%d cl:%d", qtype, qclass);
902
903 if (qclass != 1) {
904 ngx_log_error(r->log_level, r->log, 0,
905 "unknown query class %d in DNS response", qclass);
906 return;
907 }
908
909 switch (qtype) {
910
911 case NGX_RESOLVE_A:
912
913 ngx_resolver_process_a(r, buf, n, ident, code, nan,
914 i + sizeof(ngx_resolver_qs_t));
915
916 break;
917
918 case NGX_RESOLVE_PTR:
919
920 ngx_resolver_process_ptr(r, buf, n, ident, code, nan);
921
922 break;
923
924 default:
925 ngx_log_error(r->log_level, r->log, 0,
926 "unknown query type %d in DNS response", qtype);
927 return;
928 }
929
930 return;
931
932 short_response:
933
934 err = "short dns response";
935
936 done:
937
938 ngx_log_error(r->log_level, r->log, 0, err);
939
940 return;
941 }
942
943
944 static void
945 ngx_resolver_process_a(ngx_resolver_t *r, u_char *buf, size_t last,
946 ngx_uint_t ident, ngx_uint_t code, ngx_uint_t nan, ngx_uint_t ans)
947 {
948 char *err;
949 u_char *cname;
950 size_t len;
951 uint32_t hash;
952 in_addr_t addr, *addrs;
953 ngx_str_t name;
954 ngx_uint_t qtype, qident, naddrs, a, i, n, start;
955 ngx_resolver_an_t *an;
956 ngx_resolver_ctx_t *ctx, *next;
957 ngx_resolver_node_t *rn;
958
959 if (ngx_resolver_copy(r, &name, buf, &buf[12], &buf[last]) != NGX_OK) {
960 return;
961 }
962
963 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0, "resolver qs:%V", &name);
964
965 hash = ngx_crc32_short(name.data, name.len);
966
967 /* lock name mutex */
968
969 rn = ngx_resolver_lookup_name(r, &name, hash);
970
971 if (rn == NULL || rn->query == NULL) {
972 ngx_log_error(r->log_level, r->log, 0,
973 "unexpected response for %V", &name);
974 goto failed;
975 }
976
977 qident = (rn->query[0] << 8) + rn->query[1];
978
979 if (ident != qident) {
980 ngx_log_error(r->log_level, r->log, 0,
981 "wrong ident %d response for %V, expect %d",
982 ident, &name, qident);
983 goto failed;
984 }
985
986 if (code == 0 && nan == 0) {
987 code = 3; /* NXDOMAIN */
988 }
989
990 if (code) {
991 next = rn->waiting;
992 rn->waiting = NULL;
993
994 ngx_queue_remove(&rn->queue);
995
996 ngx_rbtree_delete(&r->name_rbtree, &rn->node);
997
998 ngx_resolver_free_node(r, rn);
999
1000 /* unlock name mutex */
1001
1002 while (next) {
1003 ctx = next;
1004 ctx->state = code;
1005 next = ctx->next;
1006
1007 ctx->handler(ctx);
1008 }
1009
1010 return;
1011 }
1012
1013 i = ans;
1014 naddrs = 0;
1015 addr = 0;
1016 addrs = NULL;
1017 cname = NULL;
1018 qtype = 0;
1019
1020 for (a = 0; a < nan; a++) {
1021
1022 start = i;
1023
1024 while (i < last) {
1025
1026 if (buf[i] & 0xc0) {
1027 i += 2;
1028 goto found;
1029 }
1030
1031 if (buf[i] == 0) {
1032 i++;
1033 goto test_length;
1034 }
1035
1036 i += 1 + buf[i];
1037 }
1038
1039 goto short_response;
1040
1041 test_length:
1042
1043 if (i - start < 2) {
1044 err = "invalid name in dns response";
1045 goto invalid;
1046 }
1047
1048 found:
1049
1050 if (i + sizeof(ngx_resolver_an_t) >= last) {
1051 goto short_response;
1052 }
1053
1054 an = (ngx_resolver_an_t *) &buf[i];
1055
1056 qtype = (an->type_hi << 8) + an->type_lo;
1057 len = (an->len_hi << 8) + an->len_lo;
1058
1059 if (qtype == NGX_RESOLVE_A) {
1060
1061 i += sizeof(ngx_resolver_an_t);
1062
1063 if (i + len > last) {
1064 goto short_response;
1065 }
1066
1067 addr = htonl((buf[i] << 24) + (buf[i + 1] << 16)
1068 + (buf[i + 2] << 8) + (buf[i + 3]));
1069
1070 naddrs++;
1071
1072 i += len;
1073
1074 } else if (qtype == NGX_RESOLVE_CNAME) {
1075 cname = &buf[i] + sizeof(ngx_resolver_an_t);
1076 i += sizeof(ngx_resolver_an_t) + len;
1077 }
1078 }
1079
1080 ngx_log_debug2(NGX_LOG_DEBUG_CORE, r->log, 0,
1081 "resolver naddrs:%ui cname:%p", naddrs, cname);
1082
1083 if (naddrs) {
1084
1085 if (naddrs == 1) {
1086 rn->u.addr = addr;
1087
1088 } else {
1089
1090 addrs = ngx_resolver_alloc(r, naddrs * sizeof(in_addr_t));
1091 if (addrs == NULL) {
1092 return;
1093 }
1094
1095 n = 0;
1096 i = ans;
1097
1098 for (a = 0; a < nan; a++) {
1099
1100 for ( ;; ) {
1101
1102 if (buf[i] & 0xc0) {
1103 i += 2;
1104 goto ok;
1105 }
1106
1107 if (buf[i] == 0) {
1108 i++;
1109 goto ok;
1110 }
1111
1112 i += 1 + buf[i];
1113 }
1114
1115 ok:
1116
1117 an = (ngx_resolver_an_t *) &buf[i];
1118
1119 qtype = (an->type_hi << 8) + an->type_lo;
1120 len = (an->len_hi << 8) + an->len_lo;
1121
1122 i += sizeof(ngx_resolver_an_t);
1123
1124 if (qtype == NGX_RESOLVE_A) {
1125
1126 addrs[n++] = htonl((buf[i] << 24) + (buf[i + 1] << 16)
1127 + (buf[i + 2] << 8) + (buf[i + 3]));
1128
1129 if (n == naddrs) {
1130 break;
1131 }
1132 }
1133
1134 i += len;
1135 }
1136
1137 rn->u.addrs = addrs;
1138
1139 addrs = ngx_resolver_dup(r, rn->u.addrs,
1140 naddrs * sizeof(in_addr_t));
1141 if (addrs == NULL) {
1142 return;
1143 }
1144 }
1145
1146 rn->naddrs = (u_short) naddrs;
1147
1148 ngx_queue_remove(&rn->queue);
1149
1150 rn->valid = ngx_time() + r->valid;
1151 rn->expire = ngx_time() + r->expire;
1152
1153 ngx_queue_insert_head(&r->name_expire_queue, &rn->queue);
1154
1155 next = rn->waiting;
1156 rn->waiting = NULL;
1157
1158 /* unlock name mutex */
1159
1160 while (next) {
1161 ctx = next;
1162 ctx->state = NGX_OK;
1163 ctx->naddrs = naddrs;
1164 ctx->addrs = (naddrs == 1) ? &ctx->addr : addrs;
1165 ctx->addr = addr;
1166 next = ctx->next;
1167
1168 ctx->handler(ctx);
1169 }
1170
1171 if (naddrs) {
1172 ngx_resolver_free(r, addrs);
1173 }
1174
1175 return;
1176
1177 } else if (cname) {
1178
1179 /* CNAME only */
1180
1181 if (ngx_resolver_copy(r, &name, buf, cname, &buf[last]) != NGX_OK) {
1182 return;
1183 }
1184
1185 ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
1186 "resolver cname:\"%V\"", &name);
1187
1188 ngx_queue_remove(&rn->queue);
1189
1190 rn->cnlen = (u_short) name.len;
1191 rn->u.cname = name.data;
1192 rn-