1 /*
2 SSSD
3
4 Fail over helper functions.
5
6 Authors:
7 Martin Nagy <mnagy@redhat.com>
8 Jakub Hrozek <jhrozek@redhat.com>
9
10 Copyright (C) Red Hat, Inc 2010
11
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 3 of the License, or
15 (at your option) any later version.
16
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
21
22 You should have received a copy of the GNU General Public License
23 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 */
25
26 #include <sys/time.h>
27
28 #include <errno.h>
29 #include <stdbool.h>
30 #include <strings.h>
31 #include <talloc.h>
32
33 #include "util/dlinklist.h"
34 #include "util/refcount.h"
35 #include "util/util.h"
36 #include "providers/fail_over.h"
37 #include "resolv/async_resolv.h"
38
39 #define STATUS_DIFF(p, now) ((now).tv_sec - (p)->last_status_change.tv_sec)
40 #define SERVER_NAME(s) ((s)->common ? (s)->common->name : "(no name)")
41
42 #define DEFAULT_PORT_STATUS PORT_NEUTRAL
43 #define DEFAULT_SERVER_STATUS SERVER_NAME_NOT_RESOLVED
44 #define DEFAULT_SRV_STATUS SRV_NEUTRAL
45
46 enum srv_lookup_status {
47 SRV_NEUTRAL, /* We didn't try this SRV lookup yet */
48 SRV_RESOLVED, /* This SRV lookup is resolved */
49 SRV_NOT_RESOLVED, /* Could not resolve this SRV lookup */
50 SRV_EXPIRED /* Need to refresh the SRV query */
51 };
52
53 struct fo_ctx {
54 struct fo_service *service_list;
55 struct server_common *server_common_list;
56
57 struct fo_options *opts;
58 };
59
60 struct fo_service {
61 struct fo_service *prev;
62 struct fo_service *next;
63
64 struct fo_ctx *ctx;
65 char *name;
66 struct fo_server *active_server;
67 struct fo_server *last_tried_server;
68 struct fo_server *server_list;
69 };
70
71 struct fo_server {
72 struct fo_server *prev;
73 struct fo_server *next;
74
75 void *user_data;
76 int port;
77 int port_status;
78 struct srv_data *srv_data;
79 struct fo_service *service;
80 struct timeval last_status_change;
81 struct server_common *common;
82 };
83
84 struct server_common {
85 REFCOUNT_COMMON;
86
87 struct fo_ctx *ctx;
88
89 struct server_common *prev;
90 struct server_common *next;
91
92 char *name;
93 struct hostent *hostent;
94 struct resolve_service_request *request_list;
95 int server_status;
96 struct timeval last_status_change;
97 };
98
99 struct srv_data {
100 char *domain;
101 char *proto;
102 char *srv;
103
104 struct fo_server *meta;
105
106 int srv_lookup_status;
107 struct timeval last_status_change;
108 };
109
110 struct resolve_service_request {
111 struct resolve_service_request *prev;
112 struct resolve_service_request *next;
113
114 struct server_common *server_common;
115 struct tevent_req *req;
116 };
117
118 struct status {
119 int value;
120 struct timeval last_change;
121 };
122
123 struct fo_ctx *
124 fo_context_init(TALLOC_CTX *mem_ctx, struct fo_options *opts)
125 {
126 struct fo_ctx *ctx;
127
128 ctx = talloc_zero(mem_ctx, struct fo_ctx);
129 if (ctx == NULL) {
130 DEBUG(1, ("No memory\n"));
131 return NULL;
132 }
133 ctx->opts = talloc_zero(ctx, struct fo_options);
134 if (ctx->opts == NULL) {
135 DEBUG(1, ("No memory\n"));
136 return NULL;
137 }
138
139 ctx->opts->srv_retry_timeout = opts->srv_retry_timeout;
140 ctx->opts->retry_timeout = opts->retry_timeout;
141 ctx->opts->family_order = opts->family_order;
142
143 DEBUG(3, ("Created new fail over context, retry timeout is %d\n",
144 ctx->opts->retry_timeout));
145 return ctx;
146 }
147
148 static const char *
149 str_port_status(enum port_status status)
150 {
151 switch (status) {
152 case PORT_NEUTRAL:
153 return "neutral";
154 case PORT_WORKING:
155 return "working";
156 case PORT_NOT_WORKING:
157 return "not working";
158 }
159
160 return "unknown port status";
161 }
162
163 static const char *
164 str_srv_data_status(enum srv_lookup_status status)
165 {
166 switch (status) {
167 case SRV_NEUTRAL:
168 return "neutral";
169 case SRV_RESOLVED:
170 return "resolved";
171 case SRV_NOT_RESOLVED:
172 return "not resolved";
173 case SRV_EXPIRED:
174 return "expired";
175 }
176
177 return "unknown SRV lookup status";
178 }
179
180 static const char *
181 str_server_status(enum server_status status)
182 {
183 switch (status) {
184 case SERVER_NAME_NOT_RESOLVED:
185 return "name not resolved";
186 case SERVER_RESOLVING_NAME:
187 return "resolving name";
188 case SERVER_NAME_RESOLVED:
189 return "name resolved";
190 case SERVER_WORKING:
191 return "working";
192 case SERVER_NOT_WORKING:
193 return "not working";
194 }
195
196 return "unknown server status";
197 }
198
199 int fo_is_srv_lookup(struct fo_server *s)
200 {
201 return s && s->srv_data;
202 }
203
204 static char *
205 get_srv_query(TALLOC_CTX *mem_ctx, struct fo_server *server)
206 {
207 char *query;
208
209 if (!fo_is_srv_lookup(server)) {
210 return NULL;
211 }
212
213 query = talloc_asprintf(mem_ctx, "_%s._%s.%s", server->srv_data->srv,
214 server->srv_data->proto,
215 server->srv_data->domain);
216 return query;
217 }
218
219 static struct fo_server *
220 collapse_srv_lookup(struct fo_server *server)
221 {
222 struct fo_server *tmp, *meta;
223
224 meta = server->srv_data->meta;
225 DEBUG(4, ("Need to refresh SRV lookup for domain %s\n", meta->srv_data->domain))
226
227 if (server != meta) {
228 while (server->prev && server->prev->srv_data == meta->srv_data) {
229 tmp = server->prev;
230 DLIST_REMOVE(server->service->server_list, tmp);
231 talloc_zfree(tmp);
232 }
233 while (server->next && server->next->srv_data == meta->srv_data) {
234 tmp = server->next;
235 DLIST_REMOVE(server->service->server_list, tmp);
236 talloc_zfree(tmp);
237 }
238
239 if (server == server->service->active_server) {
240 server->service->active_server = NULL;
241 }
242 if (server == server->service->last_tried_server) {
243 server->service->last_tried_server = meta;
244 }
245
246 /* add back the meta server to denote SRV lookup */
247 DLIST_ADD_AFTER(server->service->server_list, meta, server);
248 DLIST_REMOVE(server->service->server_list, server);
249 talloc_zfree(server);
250 }
251
252 meta->srv_data->srv_lookup_status = SRV_NEUTRAL;
253 meta->srv_data->last_status_change.tv_sec = 0;
254
255 return meta;
256 }
257
258 static enum srv_lookup_status
259 get_srv_data_status(struct srv_data *data)
260 {
261 struct timeval tv;
262 time_t timeout;
263
264 timeout = data->meta->service->ctx->opts->srv_retry_timeout;
265 gettimeofday(&tv, NULL);
266
267 if (timeout && STATUS_DIFF(data, tv) > timeout) {
268 switch(data->srv_lookup_status) {
269 case SRV_EXPIRED:
270 case SRV_NEUTRAL:
271 break;
272 case SRV_RESOLVED:
273 data->srv_lookup_status = SRV_EXPIRED;
274 data->last_status_change.tv_sec = 0;
275 break;
276 case SRV_NOT_RESOLVED:
277 data->srv_lookup_status = SRV_NEUTRAL;
278 data->last_status_change.tv_sec = 0;
279 break;
280 default:
281 DEBUG(1, ("Unknown state for SRV server!\n"));
282 }
283 }
284
285 return data->srv_lookup_status;
286 }
287
288 static void
289 set_srv_data_status(struct srv_data *data, enum srv_lookup_status status)
290 {
291 DEBUG(4, ("Marking SRV lookup of service '%s' as '%s'\n",
292 data->meta->service->name, str_srv_data_status(status)));
293
294 gettimeofday(&data->last_status_change, NULL);
295 data->srv_lookup_status = status;
296 }
297
298 /*
299 * This function will return the status of the server. If the status was
300 * last updated a long time ago, we will first reset the status.
301 */
302 static enum server_status
303 get_server_status(struct fo_server *server)
304 {
305 struct timeval tv;
306 time_t timeout;
307
308 if (server->common == NULL)
309 return SERVER_NAME_RESOLVED;
310
311 DEBUG(7, ("Status of server '%s' is '%s'\n", SERVER_NAME(server),
312 str_server_status(server->common->server_status)));
313
314 timeout = server->service->ctx->opts->retry_timeout;
315 if (timeout != 0 && server->common->server_status == SERVER_NOT_WORKING) {
316 gettimeofday(&tv, NULL);
317 if (STATUS_DIFF(server->common, tv) > timeout) {
318 DEBUG(4, ("Reseting the server status of '%s'\n",
319 SERVER_NAME(server)));
320 server->common->server_status = SERVER_NAME_NOT_RESOLVED;
321 server->last_status_change.tv_sec = 0;
322 }
323 }
324
325 return server->common->server_status;
326 }
327
328 /*
329 * This function will return the status of the service. If the status was
330 * last updated a long time ago, we will first reset the status.
331 */
332 static enum port_status
333 get_port_status(struct fo_server *server)
334 {
335 struct timeval tv;
336 time_t timeout;
337
338 DEBUG(7, ("Port status of port %d for server '%s' is '%s'\n", server->port,
339 SERVER_NAME(server), str_port_status(server->port_status)));
340
341 timeout = server->service->ctx->opts->retry_timeout;
342 if (timeout != 0 && server->port_status == PORT_NOT_WORKING) {
343 gettimeofday(&tv, NULL);
344 if (STATUS_DIFF(server, tv) > timeout) {
345 DEBUG(4, ("Reseting the status of port %d for server '%s'\n",
346 server->port, SERVER_NAME(server)));
347 server->port_status = PORT_NEUTRAL;
348 server->last_status_change.tv_sec = tv.tv_sec;
349 }
350 }
351
352 return server->port_status;
353 }
354
355 static int
356 server_works(struct fo_server *server)
357 {
358 if (get_server_status(server) == SERVER_NOT_WORKING)
359 return 0;
360
361 return 1;
362 }
363
364 static int
365 service_works(struct fo_server *server)
366 {
367 if (!server_works(server))
368 return 0;
369 if (get_port_status(server) == PORT_NOT_WORKING)
370 return 0;
371
372 return 1;
373 }
374
375 static int
376 service_destructor(struct fo_service *service)
377 {
378 DLIST_REMOVE(service->ctx->service_list, service);
379 return 0;
380 }
381
382 int
383 fo_new_service(struct fo_ctx *ctx, const char *name,
384 struct fo_service **_service)
385 {
386 struct fo_service *service;
387 int ret;
388
389 DEBUG(3, ("Creating new service '%s'\n", name));
390 ret = fo_get_service(ctx, name, &service);
391 if (ret == EOK) {
392 DEBUG(5, ("Service '%s' already exists\n", name));
393 if (_service) {
394 *_service = service;
395 }
396 return EEXIST;
397 } else if (ret != ENOENT) {
398 return ret;
399 }
400
401 service = talloc_zero(ctx, struct fo_service);
402 if (service == NULL)
403 return ENOMEM;
404
405 service->name = talloc_strdup(service, name);
406 if (service->name == NULL) {
407 talloc_free(service);
408 return ENOMEM;
409 }
410
411 service->ctx = ctx;
412 DLIST_ADD(ctx->service_list, service);
413
414 talloc_set_destructor(service, service_destructor);
415 if (_service) {
416 *_service = service;
417 }
418
419 return EOK;
420 }
421
422 int
423 fo_get_service(struct fo_ctx *ctx, const char *name,
424 struct fo_service **_service)
425 {
426 struct fo_service *service;
427
428 DLIST_FOR_EACH(service, ctx->service_list) {
429 if (!strcmp(name, service->name)) {
430 *_service = service;
431 return EOK;
432 }
433 }
434
435 return ENOENT;
436 }
437
438 static int
439 get_server_common(TALLOC_CTX *mem_ctx, struct fo_ctx *ctx, const char *name,
440 struct server_common **_common)
441 {
442 struct server_common *common;
443
444 DLIST_FOR_EACH(common, ctx->server_common_list) {
445 if (!strcasecmp(name, common->name)) {
446 *_common = rc_reference(mem_ctx, struct server_common, common);
447 if (_common == NULL)
448 return ENOMEM;
449 return EOK;
450 }
451 }
452
453 return ENOENT;
454 }
455
456 static int server_common_destructor(void *memptr)
457 {
458 struct server_common *common;
459
460 common = talloc_get_type(memptr, struct server_common);
461 if (common->request_list) {
462 DEBUG(1, ("BUG: pending requests still associated with this server\n"));
463 return -1;
464 }
465 DLIST_REMOVE(common->ctx->server_common_list, common);
466
467 return 0;
468 }
469
470 static struct server_common *
471 create_server_common(TALLOC_CTX *mem_ctx, struct fo_ctx *ctx, const char *name)
472 {
473 struct server_common *common;
474
475 common = rc_alloc(mem_ctx, struct server_common);
476 if (common == NULL)
477 return NULL;
478
479 common->name = talloc_strdup(common, name);
480 if (common->name == NULL) {
481 talloc_free(common);
482 return NULL;
483 }
484
485 common->ctx = ctx;
486 common->prev = NULL;
487 common->next = NULL;
488 common->hostent = NULL;
489 common->request_list = NULL;
490 common->server_status = DEFAULT_SERVER_STATUS;
491 common->last_status_change.tv_sec = 0;
492 common->last_status_change.tv_usec = 0;
493
494 talloc_set_destructor((TALLOC_CTX *) common, server_common_destructor);
495 DLIST_ADD_END(ctx->server_common_list, common, struct server_common *);
496 return common;
497 }
498
499 int
500 fo_add_srv_server(struct fo_service *service, const char *srv,
501 const char *domain, const char *proto, void *user_data)
502 {
503 struct fo_server *server;
504
505 DEBUG(3, ("Adding new SRV server in domain '%s', to service '%s'\n",
506 domain, service->name));
507
508 DLIST_FOR_EACH(server, service->server_list) {
509 if (server->user_data != user_data)
510 continue;
511
512 if (fo_is_srv_lookup(server)) {
513 if (strcasecmp(server->srv_data->domain, domain) == 0 &&
514 strcasecmp(server->srv_data->proto, proto) == 0) {
515 return EEXIST;
516 }
517 }
518 }
519
520 server = talloc_zero(service, struct fo_server);
521 if (server == NULL)
522 return ENOMEM;
523
524 server->user_data = user_data;
525 server->service = service;
526 server->port_status = DEFAULT_PORT_STATUS;
527
528 /* add the SRV-specific data */
529 server->srv_data = talloc_zero(service, struct srv_data);
530 if (server->srv_data == NULL)
531 return ENOMEM;
532
533 server->srv_data->domain = talloc_strdup(server->srv_data, domain);
534 server->srv_data->proto = talloc_strdup(server->srv_data, proto);
535 server->srv_data->srv = talloc_strdup(server->srv_data, srv);
536 if (server->srv_data->domain == NULL ||
537 server->srv_data->proto == NULL ||
538 server->srv_data->srv == NULL)
539 return ENOMEM;
540
541 server->srv_data->meta = server;
542 server->srv_data->srv_lookup_status = DEFAULT_SRV_STATUS;
543 server->srv_data->last_status_change.tv_sec = 0;
544
545 DLIST_ADD_END(service->server_list, server, struct fo_server *);
546 return EOK;
547 }
548
549 static struct fo_server *
550 create_fo_server(struct fo_service *service, const char *name,
551 int port, void *user_data)
552 {
553 struct fo_server *server;
554 int ret;
555
556 server = talloc_zero(service, struct fo_server);
557 if (server == NULL)
558 return NULL;
559
560 server->port = port;
561 server->user_data = user_data;
562 server->service = service;
563 server->port_status = DEFAULT_PORT_STATUS;
564
565 if (name != NULL) {
566 ret = get_server_common(server, service->ctx, name, &server->common);
567 if (ret == ENOENT) {
568 server->common = create_server_common(server, service->ctx, name);
569 if (server->common == NULL) {
570 talloc_free(server);
571 return NULL;
572 }
573 } else if (ret != EOK) {
574 talloc_free(server);
575 return NULL;
576 }
577 }
578
579 return server;
580 }
581
582 int
583 fo_add_server(struct fo_service *service, const char *name, int port,
584 void *user_data)
585 {
586 struct fo_server *server;
587
588 DEBUG(3, ("Adding new server '%s', to service '%s'\n",
589 name ? name : "(no name)", service->name));
590 DLIST_FOR_EACH(server, service->server_list) {
591 if (server->port != port || server->user_data != user_data)
592 continue;
593 if (name == NULL && server->common == NULL) {
594 return EEXIST;
595 } else if (name != NULL && server->common != NULL) {
596 if (!strcasecmp(name, server->common->name))
597 return EEXIST;
598 }
599 }
600
601 server = create_fo_server(service, name, port, user_data);
602 if (!server) {
603 return ENOMEM;
604 }
605
606 DLIST_ADD_END(service->server_list, server, struct fo_server *);
607
608 return EOK;
609 }
610
611 static int
612 get_first_server_entity(struct fo_service *service, struct fo_server **_server)
613 {
614 struct fo_server *server;
615
616 /* If we already have a working server, use that one. */
617 server = service->active_server;
618 if (server != NULL) {
619 if (service_works(server)) {
620 goto done;
621 }
622 service->active_server = NULL;
623 }
624
625 /*
626 * Otherwise iterate through the server list.
627 */
628
629 /* First, try servers after the last one we tried. */
630 if (service->last_tried_server != NULL) {
631 DLIST_FOR_EACH(server, service->last_tried_server->next) {
632 if (service_works(server)) {
633 goto done;
634 }
635 }
636 }
637
638 /* If none were found, try at the start. */
639 DLIST_FOR_EACH(server, service->server_list) {
640 if (service_works(server)) {
641 goto done;
642 }
643 if (server == service->last_tried_server) {
644 break;
645 }
646 }
647
648 service->last_tried_server = NULL;
649 return ENOENT;
650
651 done:
652 service->last_tried_server = server;
653 *_server = server;
654 return EOK;
655 }
656
657 static int
658 resolve_service_request_destructor(struct resolve_service_request *request)
659 {
660 DLIST_REMOVE(request->server_common->request_list, request);
661 return 0;
662 }
663
664 static int
665 set_lookup_hook(struct fo_server *server, struct tevent_req *req)
666 {
667 struct resolve_service_request *request;
668
669 request = talloc(req, struct resolve_service_request);
670 if (request == NULL) {
671 DEBUG(1, ("No memory\n"));
672 talloc_free(request);
673 return ENOMEM;
674 }
675 request->server_common = rc_reference(request, struct server_common,
676 server->common);
677 if (request->server_common == NULL) {
678 talloc_free(request);
679 return ENOMEM;
680 }
681 request->req = req;
682 DLIST_ADD(server->common->request_list, request);
683 talloc_set_destructor(request, resolve_service_request_destructor);
684
685 return EOK;
686 }
687
688 /*******************************************************************
689 * Get server to connect to. *
690 *******************************************************************/
691
692 struct resolve_service_state {
693 struct fo_server *server;
694
695 struct resolv_ctx *resolv;
696 struct tevent_context *ev;
697 struct fo_ctx *fo_ctx;
698 };
699
700
701 static void fo_resolve_service_cont(struct tevent_req *subreq);
702 static void fo_resolve_service_done(struct tevent_req *subreq);
703 static bool fo_resolve_service_server(struct tevent_req *req);
704
705 /* Forward declarations for SRV resolving */
706 static struct tevent_req *
707 resolve_srv_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
708 struct resolv_ctx *resolv, struct fo_ctx *ctx,
709 struct fo_server *server);
710 static int
711 resolve_srv_recv(struct tevent_req *req, struct fo_server **server);
712
713 struct tevent_req *
714 fo_resolve_service_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
715 struct resolv_ctx *resolv, struct fo_ctx *ctx,
716 struct fo_service *service)
717 {
718 int ret;
719 struct fo_server *server;
720 struct tevent_req *req;
721 struct tevent_req *subreq;
722 struct resolve_service_state *state;
723
724 DEBUG(4, ("Trying to resolve service '%s'\n", service->name));
725 req = tevent_req_create(mem_ctx, &state, struct resolve_service_state);
726 if (req == NULL)
727 return NULL;
728
729 state->resolv = resolv;
730 state->ev = ev;
731 state->fo_ctx = ctx;
732
733 ret = get_first_server_entity(service, &server);
734 if (ret != EOK) {
735 DEBUG(1, ("No available servers for service '%s'\n", service->name));
736 goto done;
737 }
738
739 if (fo_is_srv_lookup(server)) {
740 /* Don't know the server yet, must do a SRV lookup */
741 subreq = resolve_srv_send(state, ev, resolv,
742 ctx, server);
743 if (subreq == NULL) {
744 ret = ENOMEM;
745 goto done;
746 }
747
748 tevent_req_set_callback(subreq,
749 fo_resolve_service_cont,
750 req);
751 return req;
752 }
753
754 /* This is a regular server, just do hostname lookup */
755 state->server = server;
756 if (fo_resolve_service_server(req)) {
757 tevent_req_post(req, ev);
758 }
759
760 ret = EOK;
761 done:
762 if (ret != EOK) {
763 tevent_req_error(req, ret);
764 tevent_req_post(req, ev);
765 }
766 return req;
767 }
768
769 static void set_server_common_status(struct server_common *common,
770 enum server_status status);
771
772 /* SRV resolving finished, see if we got server to work with */
773 static void
774 fo_resolve_service_cont(struct tevent_req *subreq)
775 {
776 struct tevent_req *req = tevent_req_callback_data(subreq,
777 struct tevent_req);
778 struct resolve_service_state *state = tevent_req_data(req,
779 struct resolve_service_state);
780 int ret;
781
782 ret = resolve_srv_recv(subreq, &state->server);
783 talloc_zfree(subreq);
784
785 if (ret) {
786 tevent_req_error(req, ret);
787 return;
788 }
789
790 fo_resolve_service_server(req);
791 }
792
793 static bool
794 fo_resolve_service_server(struct tevent_req *req)
795 {
796 struct resolve_service_state *state = tevent_req_data(req,
797 struct resolve_service_state);
798 struct tevent_req *subreq;
799 int ret;
800
801 switch (get_server_status(state->server)) {
802 case SERVER_NAME_NOT_RESOLVED: /* Request name resolution. */
803 subreq = resolv_gethostbyname_send(state->server->common,
804 state->ev, state->resolv,
805 state->server->common->name,
806 state->fo_ctx->opts->family_order);
807 if (subreq == NULL) {
808 tevent_req_error(req, ENOMEM);
809 return true;
810 }
811 tevent_req_set_callback(subreq, fo_resolve_service_done, req);
812 fo_set_server_status(state->server, SERVER_RESOLVING_NAME);
813 /* FALLTHROUGH */
814 case SERVER_RESOLVING_NAME:
815 /* Name resolution is already under way. Just add ourselves into the
816 * waiting queue so we get notified after the operation is finished. */
817 ret = set_lookup_hook(state->server, req);
818 if (ret != EOK) {
819 tevent_req_error(req, ret);
820 return true;
821 }
822 break;
823 default: /* The name is already resolved. Return immediately. */
824 tevent_req_done(req);
825 return true;
826 }
827
828 return false;
829 }
830
831 static void
832 fo_resolve_service_done(struct tevent_req *subreq)
833 {
834 struct tevent_req *req = tevent_req_callback_data(subreq,
835 struct tevent_req);
836 struct resolve_service_state *state = tevent_req_data(req,
837 struct resolve_service_state);
838 struct server_common *common;
839 int resolv_status;
840 struct resolve_service_request *request;
841 int ret;
842
843 if (state->server->common->hostent != NULL) {
844 talloc_zfree(state->server->common->hostent);
845 }
846
847 ret = resolv_gethostbyname_recv(subreq, state->server->common,
848 &resolv_status, NULL,
849 &state->server->common->hostent);
850 talloc_zfree(subreq);
851 if (ret != EOK) {
852 DEBUG(1, ("Failed to resolve server '%s': %s\n",
853 state->server->common->name,
854 resolv_strerror(resolv_status)));
855 set_server_common_status(state->server->common, SERVER_NOT_WORKING);
856 } else {
857 set_server_common_status(state->server->common, SERVER_NAME_RESOLVED);
858 }
859
860 /* Take care of all requests for this server. */
861 common = state->server->common; /* state can disappear now */
862 while ((request = common->request_list) != NULL) {
863 DLIST_REMOVE(common->request_list, request);
864 if (resolv_status) {
865 /* FIXME FIXME: resolv_status is an ARES error.
866 * but any caller will expect classic error codes.
867 * also the send() function may return ENOENT, so this mix
868 * IS explosive (ENOENT = 2 = ARES_EFORMER) */
869 tevent_req_error(request->req, resolv_status);
870 } else {
871 tevent_req_done(request->req);
872 }
873 }
874 }
875
876 int
877 fo_resolve_service_recv(struct tevent_req *req, struct fo_server **server)
878 {
879 struct resolve_service_state *state;
880
881 state = tevent_req_data(req, struct resolve_service_state);
882
883 /* always return the server if asked for, otherwise the caller
884 * cannot mark it as faulty in case we return an error */
885 if (server)
886 *server = state->server;
887
888 TEVENT_REQ_RETURN_ON_ERROR(req);
889
890 return EOK;
891 }
892
893 /*******************************************************************
894 * Resolve the server to connect to using a SRV query. *
895 *******************************************************************/
896
897 static void resolve_srv_done(struct tevent_req *subreq);
898
899 struct resolve_srv_state {
900 struct fo_server *meta;
901 struct fo_service *service;
902
903 struct fo_server *out;
904
905 struct resolv_ctx *resolv;
906 struct tevent_context *ev;
907 struct fo_ctx *fo_ctx;
908 };
909
910 static struct tevent_req *
911 resolve_srv_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
912 struct resolv_ctx *resolv, struct fo_ctx *ctx,
913 struct fo_server *server)
914 {
915 int ret;
916 char *query;
917 struct tevent_req *req;
918 struct tevent_req *subreq;
919 struct resolve_srv_state *state;
920 int status;
921
922 req = tevent_req_create(mem_ctx, &state, struct resolve_srv_state);
923 if (req == NULL)
924 return NULL;
925
926 state->service = server->service;
927 state->ev = ev;
928 state->resolv = resolv;
929 state->fo_ctx = ctx;
930 state->meta = server;
931
932 status = get_srv_data_status(server->srv_data);
933 DEBUG(6, ("The status of SRV lookup is %s\n",
934 str_srv_data_status(status)));
935 switch(status) {
936 case SRV_EXPIRED: /* Need a refresh */
937 state->meta = collapse_srv_lookup(server);
938 /* FALLTHROUGH */
939 case SRV_NEUTRAL: /* Request SRV lookup */
940 query = get_srv_query(state, state->meta);
941 if (!query) {
942 ret = ENOMEM;
943 goto done;
944 }
945 DEBUG(4, ("Searching for servers via SRV query '%s'\n", query));
946
947 subreq = resolv_getsrv_send(state, ev, resolv, query);
948 if (subreq == NULL) {
949 ret = ENOMEM;
950 goto done;
951 }
952 tevent_req_set_callback(subreq, resolve_srv_done, req);
953 break;
954 case SRV_NOT_RESOLVED: /* query could not be resolved but don't retry yet */
955 ret = EIO;
956 goto done;
957 case SRV_RESOLVED: /* The query is resolved and valid. Return. */
958 state->out = server;
959 tevent_req_done(req);
960 tevent_req_post(req, state->ev);
961 return req;
962 default:
963 DEBUG(1, ("Unexpected status %d for a SRV server\n", status));
964 ret = EIO;
965 break;
966 }
967
968 ret = EOK;
969 done:
970 if (ret != EOK) {
971 tevent_req_error(req, ret);
972 tevent_req_post(req, ev);
973 }
974 return req;
975 }
976
977 static void
978 resolve_srv_done(struct tevent_req *subreq)
979 {
980 struct tevent_req *req = tevent_req_callback_data(subreq,
981 struct tevent_req);
982 struct resolve_srv_state *state = tevent_req_data(req,
983 struct resolve_srv_state);
984 struct ares_srv_reply *reply_list;
985 struct ares_srv_reply *reply;
986 struct fo_server *server = NULL;
987 struct fo_server *srv_list = NULL;
988 int ret;
989 int resolv_status;
990
991 ret = resolv_getsrv_recv(state, subreq,
992 &resolv_status, NULL, &reply_list);
993 talloc_free(subreq);
994 if (ret != EOK) {
995 DEBUG(1, ("SRV query failed %s\n",
996 resolv_strerror(resolv_status)));
997 fo_set_port_status(state->meta, PORT_NOT_WORKING);
998 goto fail;
999 }
1000
1001 ret = resolv_sort_srv_reply(state, &reply_list);
1002 if (ret != EOK) {
1003 DEBUG(1, ("Could not sort the answers from DNS [%d]: %s\n",
1004 ret, strerror(ret)));
1005 fo_set_port_status(state->meta, PORT_NOT_WORKING);
1006 goto fail;
1007 }
1008
1009 for (reply = reply_list; reply; reply = reply->next) {
1010 ret = EOK;
1011 DLIST_FOR_EACH(server, state->service->server_list) {
1012 if (server->port == reply->port) {
1013 ret = EEXIST;
1014 break;
1015 }
1016 }
1017 if (ret == EEXIST) continue;
1018
1019 server = create_fo_server(state->service, reply->host,
1020 reply->port, state->meta->user_data);
1021 if (!server) {
1022 ret = ENOMEM;
1023 goto fail;
1024 }
1025 server->srv_data = state->meta->srv_data;
1026
1027 DLIST_ADD_END(srv_list, server, struct fo_server *);
1028 DEBUG(6, ("Inserted server '%s:%d' for service %s\n",
1029 server->common->name,
1030 server->port,
1031 state->service->name));
1032 }
1033
1034 if (srv_list) {
1035 DLIST_ADD_LIST_AFTER(state->service->server_list, state->meta,
1036 srv_list, struct fo_server *);
1037
1038 DLIST_REMOVE(state->service->server_list, state->meta);
1039 if (state->service->last_tried_server == state->meta) {
1040 state->service->last_tried_server = srv_list;
1041 }
1042
1043 state->out = srv_list;
1044 set_srv_data_status(state->meta->srv_data, SRV_RESOLVED);
1045 tevent_req_done(req);
1046 return;
1047 } else {
1048 ret = EIO;
1049 goto fail;
1050 }
1051
1052 fail:
1053 state->out = state->meta;
1054 set_srv_data_status(state->meta->srv_data, SRV_NOT_RESOLVED);
1055 tevent_req_error(req, ret);
1056 }
1057
1058 static int
1059 resolve_srv_recv(struct tevent_req *req, struct fo_server **server)
1060 {
1061 struct resolve_srv_state *state = tevent_req_data(req,
1062 struct resolve_srv_state);
1063
1064 /* always return the server if asked for, otherwise the caller
1065 * cannot mark it as faulty in case we return an error */
1066 if (server) {
1067 *server = state->out;
1068 }
1069
1070 TEVENT_REQ_RETURN_ON_ERROR(req);
1071
1072 return EOK;
1073 }
1074
1075 static void
1076 set_server_common_status(struct server_common *common,
1077 enum server_status status)
1078 {
1079 DEBUG(4, ("Marking server '%s' as '%s'\n", common->name,
1080 str_server_status(status)));
1081
1082 common->server_status = status;
1083 gettimeofday(&common->last_status_change, NULL);
1084 }
1085
1086 void
1087 fo_set_server_status(struct fo_server *server, enum server_status status)
1088 {
1089 if (server->common == NULL) {
1090 DEBUG(1, ("Bug: Trying to set server status of a name-less server\n"));
1091 return;
1092 }
1093
1094 set_server_common_status(server->common, status);
1095 }
1096
1097 void
1098 fo_set_port_status(struct fo_server *server, enum port_status status)
1099 {
1100 DEBUG(4, ("Marking port %d of server '%s' as '%s'\n", server->port,
1101 SERVER_NAME(server), str_port_status(status)));
1102
1103 server->port_status = status;
1104 gettimeofday(&server->last_status_change, NULL);
1105 if (status == PORT_WORKING) {
1106 fo_set_server_status(server, SERVER_WORKING);
1107 server->service->active_server = server;
1108 }
1109 }
1110
1111 void *
1112 fo_get_server_user_data(struct fo_server *server)
1113 {
1114 return server->user_data;
1115 }
1116
1117 int
1118 fo_get_server_port(struct fo_server *server)
1119 {
1120 return server->port;
1121 }
1122
1123 const char *fo_get_server_name(struct fo_server *server)
1124 {
Event var_compare_op: Comparing "server->common" to null implies that "server->common" might be null.
Also see events: [var_deref_op]At conditional (1): "!server->common": Taking true branch.
| At conditional (2): "fo_is_srv_lookup(server)": Taking false branch.
| | | |
1125 if (!server->common && fo_is_srv_lookup(server)) {
1126 return "SRV lookup meta-server";
1127 }
1128
Event var_deref_op: Dereferencing null variable "server->common".
| Also see events: [var_compare_op] | |
1129 return server->common->name;
1130 }
1131
1132 struct hostent *
1133 fo_get_server_hostent(struct fo_server *server)
1134 {
1135 if (server->common == NULL) {
1136 DEBUG(1, ("Bug: Trying to get hostent from a name-less server\n"));
1137 return NULL;
1138 }
1139 return server->common->hostent;
1140 }