2 * ntp_intres.c - Implements a generic blocking worker child or thread,
3 * initially to provide a nonblocking solution for DNS
4 * name to address lookups available with getaddrinfo().
6 * This is a new implementation as of 2009 sharing the filename and
7 * very little else with the prior implementation, which used a
8 * temporary file to receive a single set of requests from the parent,
9 * and a NTP mode 7 authenticated request to push back responses.
11 * A primary goal in rewriting this code was the need to support the
12 * pool configuration directive's requirement to retrieve multiple
13 * addresses resolving a single name, which has previously been
14 * satisfied with blocking resolver calls from the ntpd mainline code.
16 * A secondary goal is to provide a generic mechanism for other
17 * blocking operations to be delegated to a worker using a common
18 * model for both Unix and Windows ntpd. ntp_worker.c, work_fork.c,
19 * and work_thread.c implement the generic mechanism. This file
20 * implements the two current consumers, getaddrinfo_sometime() and the
21 * presently unused getnameinfo_sometime().
23 * Both routines deliver results to a callback and manage memory
24 * allocation, meaning there is no freeaddrinfo_sometime().
26 * The initial implementation for Unix uses a pair of unidirectional
27 * pipes, one each for requests and responses, connecting the forked
28 * blocking child worker with the ntpd mainline. The threaded code
29 * uses arrays of pointers to queue requests and responses.
31 * The parent drives the process, including scheduling sleeps between
34 * Memory is managed differently for a child process, which mallocs
35 * request buffers to read from the pipe into, whereas the threaded
36 * code mallocs a copy of the request to hand off to the worker via
37 * the queueing array. The resulting request buffer is free()d by
38 * platform-independent code. A wrinkle is the request needs to be
39 * available to the requestor during response processing.
41 * Response memory allocation is also platform-dependent. With a
42 * separate process and pipes, the response is free()d after being
43 * written to the pipe. With threads, the same memory is handed
44 * over and the requestor frees it after processing is completed.
46 * The code should be generalized to support threads on Unix using
47 * much of the same code used for Windows initially.
54 #include "ntp_workimpl.h"
63 #ifdef HAVE_SYS_TYPES_H
64 # include <sys/types.h>
66 #ifdef HAVE_NETINET_IN_H
67 #include <netinet/in.h>
69 #include <arpa/inet.h>
71 #ifdef HAVE_SYS_PARAM_H
72 # include <sys/param.h>
75 #if !defined(HAVE_RES_INIT) && defined(HAVE___RES_INIT)
76 # define HAVE_RES_INIT
79 #if defined(HAVE_RESOLV_H) && defined(HAVE_RES_INIT)
80 # ifdef HAVE_ARPA_NAMESER_H
81 # include <arpa/nameser.h> /* DNS HEADER struct */
87 # ifdef HAVE_INT32_ONLY_WITH_DNS
90 # ifdef HAVE_U_INT32_ONLY_WITH_DNS
96 #include "ntp_debug.h"
97 #include "ntp_malloc.h"
98 #include "ntp_syslog.h"
99 #include "ntp_unixtime.h"
100 #include "ntp_intres.h"
101 #include "intreswork.h"
105 * Following are implementations of getaddrinfo_sometime() and
106 * getnameinfo_sometime(). Each is implemented in three routines:
108 * getaddrinfo_sometime() getnameinfo_sometime()
109 * blocking_getaddrinfo() blocking_getnameinfo()
110 * getaddrinfo_sometime_complete() getnameinfo_sometime_complete()
112 * The first runs in the parent and marshalls (or serializes) request
113 * parameters into a request blob which is processed in the child by
114 * the second routine, blocking_*(), which serializes the results into
115 * a response blob unpacked by the third routine, *_complete(), which
116 * calls the callback routine provided with the request and frees
117 * _request_ memory allocated by the first routine. Response memory
118 * is managed by the code which calls the *_complete routines.
122 /* === typedefs === */
123 typedef struct blocking_gai_req_tag { /* marshalled args */
129 struct addrinfo hints;
131 gai_sometime_callback callback;
137 typedef struct blocking_gai_resp_tag {
141 int gai_errno; /* for EAI_SYSTEM case */
144 * Followed by ai_count struct addrinfo and then ai_count
145 * sockaddr_u and finally the canonical name strings.
149 typedef struct blocking_gni_req_tag {
158 gni_sometime_callback callback;
163 typedef struct blocking_gni_resp_tag {
166 int gni_errno; /* for EAI_SYSTEM case */
171 * Followed by hostoctets bytes of null-terminated host,
172 * then servoctets bytes of null-terminated service.
176 /* per-DNS-worker state in parent */
177 typedef struct dnschild_ctx_tag {
179 time_t next_dns_timeslot;
182 /* per-DNS-worker state in worker */
183 typedef struct dnsworker_ctx_tag {
185 time_t ignore_scheduled_before;
187 time_t next_res_init;
192 /* === variables === */
193 dnschild_ctx ** dnschild_contexts; /* parent */
194 u_int dnschild_contexts_alloc;
195 dnsworker_ctx ** dnsworker_contexts; /* child */
196 u_int dnsworker_contexts_alloc;
199 static time_t next_res_init;
203 /* === forward declarations === */
204 static u_int reserve_dnschild_ctx(void);
205 static u_int get_dnschild_ctx(void);
206 static dnsworker_ctx * get_worker_context(blocking_child *, u_int);
207 static void scheduled_sleep(time_t, time_t,
209 static void manage_dns_retry_interval(time_t *, time_t *,
212 static int should_retry_dns(int, int);
214 static void reload_resolv_conf(dnsworker_ctx *);
216 # define reload_resolv_conf(wc) \
221 static void getaddrinfo_sometime_complete(blocking_work_req,
224 static void getnameinfo_sometime_complete(blocking_work_req,
229 /* === functions === */
231 * getaddrinfo_sometime - uses blocking child to call getaddrinfo then
232 * invokes provided callback completion function.
235 getaddrinfo_sometime_ex(
237 const char * service,
238 const struct addrinfo * hints,
240 gai_sometime_callback callback,
245 blocking_gai_req * gai_req;
247 dnschild_ctx * child_ctx;
253 REQUIRE(NULL != node);
255 REQUIRE(0 == hints->ai_addrlen);
256 REQUIRE(NULL == hints->ai_addr);
257 REQUIRE(NULL == hints->ai_canonname);
258 REQUIRE(NULL == hints->ai_next);
261 idx = get_dnschild_ctx();
262 child_ctx = dnschild_contexts[idx];
264 nodesize = strlen(node) + 1;
265 servsize = strlen(service) + 1;
266 req_size = sizeof(*gai_req) + nodesize + servsize;
268 gai_req = emalloc_zero(req_size);
270 gai_req->octets = req_size;
271 gai_req->dns_idx = idx;
273 gai_req->scheduled = now;
274 gai_req->earliest = max(now, child_ctx->next_dns_timeslot);
275 child_ctx->next_dns_timeslot = gai_req->earliest;
277 gai_req->hints = *hints;
278 gai_req->retry = retry;
279 gai_req->callback = callback;
280 gai_req->context = context;
281 gai_req->nodesize = nodesize;
282 gai_req->servsize = servsize;
283 gai_req->qflags = qflags;
285 memcpy((char *)gai_req + sizeof(*gai_req), node, nodesize);
286 memcpy((char *)gai_req + sizeof(*gai_req) + nodesize, service,
289 if (queue_blocking_request(
290 BLOCKING_GETADDRINFO,
293 &getaddrinfo_sometime_complete,
296 msyslog(LOG_ERR, "unable to queue getaddrinfo request");
305 blocking_getaddrinfo(
307 blocking_pipe_header * req
310 blocking_gai_req * gai_req;
311 dnsworker_ctx * worker_ctx;
312 blocking_pipe_header * resp;
313 blocking_gai_resp * gai_resp;
316 struct addrinfo * ai_res;
317 struct addrinfo * ai;
318 struct addrinfo * serialized_ai;
319 size_t canons_octets;
325 gai_req = (void *)((char *)req + sizeof(*req));
326 node = (char *)gai_req + sizeof(*gai_req);
327 service = node + gai_req->nodesize;
329 worker_ctx = get_worker_context(c, gai_req->dns_idx);
330 scheduled_sleep(gai_req->scheduled, gai_req->earliest,
332 reload_resolv_conf(worker_ctx);
335 * Take a shot at the final size, better to overestimate
336 * at first and then realloc to a smaller size.
339 resp_octets = sizeof(*resp) + sizeof(*gai_resp) +
340 16 * (sizeof(struct addrinfo) +
341 sizeof(sockaddr_u)) +
343 resp = emalloc_zero(resp_octets);
344 gai_resp = (void *)(resp + 1);
346 TRACE(2, ("blocking_getaddrinfo given node %s serv %s fam %d flags %x\n",
347 node, service, gai_req->hints.ai_family,
348 gai_req->hints.ai_flags));
354 gai_resp->retcode = getaddrinfo(node, service, &gai_req->hints,
356 gai_resp->retry = gai_req->retry;
358 if (EAI_SYSTEM == gai_resp->retcode)
359 gai_resp->gai_errno = errno;
363 if (0 == gai_resp->retcode) {
366 gai_resp->ai_count++;
367 if (ai->ai_canonname)
368 canons_octets += strlen(ai->ai_canonname) + 1;
372 * If this query succeeded only after retrying, DNS may have
373 * just become responsive. Ignore previously-scheduled
374 * retry sleeps once for each pending request, similar to
375 * the way scheduled_sleep() does when its worker_sleep()
378 if (gai_resp->retry > INITIAL_DNS_RETRY) {
379 time_now = time(NULL);
380 worker_ctx->ignore_scheduled_before = time_now;
381 TRACE(1, ("DNS success after retry, ignoring sleeps scheduled before now (%s)\n",
382 humantime(time_now)));
387 * Our response consists of a header, followed by ai_count
388 * addrinfo structs followed by ai_count sockaddr_storage
389 * structs followed by the canonical names.
391 gai_resp->octets = sizeof(*gai_resp)
393 * (sizeof(gai_req->hints)
394 + sizeof(sockaddr_u))
397 resp_octets = sizeof(*resp) + gai_resp->octets;
398 resp = erealloc(resp, resp_octets);
399 gai_resp = (void *)(resp + 1);
401 /* cp serves as our current pointer while serializing */
402 cp = (void *)(gai_resp + 1);
405 if (0 == gai_resp->retcode) {
408 memcpy(cp, ai, sizeof(*ai));
409 serialized_ai = (void *)cp;
412 /* transform ai_canonname into offset */
413 if (NULL != ai->ai_canonname) {
414 serialized_ai->ai_canonname = (char *)canons_octets;
415 canons_octets += strlen(ai->ai_canonname) + 1;
418 /* leave fixup of ai_addr pointer for receiver */
425 INSIST(ai->ai_addrlen <= sizeof(sockaddr_u));
426 memcpy(cp, ai->ai_addr, ai->ai_addrlen);
427 cp += sizeof(sockaddr_u);
434 if (NULL != ai->ai_canonname) {
435 this_octets = strlen(ai->ai_canonname) + 1;
436 memcpy(cp, ai->ai_canonname, this_octets);
442 freeaddrinfo(ai_res);
446 * make sure our walk and earlier calc match
448 DEBUG_INSIST((size_t)(cp - (char *)resp) == resp_octets);
450 if (queue_blocking_response(c, resp, resp_octets, req)) {
451 msyslog(LOG_ERR, "blocking_getaddrinfo can not queue response");
459 getaddrinfo_sometime(
461 const char * service,
462 const struct addrinfo * hints,
464 gai_sometime_callback callback,
468 return getaddrinfo_sometime_ex(node, service, hints, retry,
469 callback, context, 0);
474 getaddrinfo_sometime_complete(
475 blocking_work_req rtype,
481 blocking_gai_req * gai_req;
482 blocking_gai_resp * gai_resp;
483 dnschild_ctx * child_ctx;
484 struct addrinfo * ai;
485 struct addrinfo * next_ai;
493 const char * fam_spec;
499 DEBUG_REQUIRE(BLOCKING_GETADDRINFO == rtype);
500 DEBUG_REQUIRE(respsize == gai_resp->octets);
502 node = (char *)gai_req + sizeof(*gai_req);
503 service = node + gai_req->nodesize;
505 child_ctx = dnschild_contexts[gai_req->dns_idx];
507 if (0 == gai_resp->retcode) {
509 * If this query succeeded only after retrying, DNS may have
510 * just become responsive.
512 if (gai_resp->retry > INITIAL_DNS_RETRY) {
513 time_now = time(NULL);
514 child_ctx->next_dns_timeslot = time_now;
515 TRACE(1, ("DNS success after retry, %u next_dns_timeslot reset (%s)\n",
516 gai_req->dns_idx, humantime(time_now)));
519 noerr = !!(gai_req->qflags & GAIR_F_IGNDNSERR);
520 again = noerr || should_retry_dns(
521 gai_resp->retcode, gai_resp->gai_errno);
523 * exponential backoff of DNS retries to 64s
525 if (gai_req->retry > 0 && again) {
526 /* log the first retry only */
527 if (INITIAL_DNS_RETRY == gai_req->retry)
529 af = gai_req->hints.ai_family;
530 fam_spec = (AF_INET6 == af)
536 if (EAI_SYSTEM == gai_resp->retcode) {
537 errno = gai_resp->gai_errno;
539 "retrying DNS %s%s: EAI_SYSTEM %d: %m",
541 gai_resp->gai_errno);
545 "retrying DNS %s%s: %s (%d)",
547 gai_strerror(gai_resp->retcode),
550 manage_dns_retry_interval(
551 &gai_req->scheduled, &gai_req->earliest,
552 &gai_req->retry, &child_ctx->next_dns_timeslot,
554 if (!queue_blocking_request(
555 BLOCKING_GETADDRINFO,
558 &getaddrinfo_sometime_complete,
563 "unable to retry hostname %s",
569 * fixup pointers in returned addrinfo array
571 ai = (void *)((char *)gai_resp + sizeof(*gai_resp));
573 for (i = gai_resp->ai_count - 1; i >= 0; i--) {
574 ai[i].ai_next = next_ai;
578 psau = (void *)((char *)ai + gai_resp->ai_count * sizeof(*ai));
579 canon_start = (char *)psau + gai_resp->ai_count * sizeof(*psau);
581 for (i = 0; i < gai_resp->ai_count; i++) {
582 if (NULL != ai[i].ai_addr)
583 ai[i].ai_addr = &psau->sa;
585 if (NULL != ai[i].ai_canonname)
586 ai[i].ai_canonname += (size_t)canon_start;
589 ENSURE((char *)psau == canon_start);
591 if (!gai_resp->ai_count)
594 (*gai_req->callback)(gai_resp->retcode, gai_resp->gai_errno,
595 gai_req->context, node, service,
596 &gai_req->hints, ai);
599 /* gai_resp is part of block freed by process_blocking_resp() */
603 #ifdef TEST_BLOCKING_WORKER
604 void gai_test_callback(int rescode, int gai_errno, void *context, const char *name, const char *service, const struct addrinfo *hints, const struct addrinfo *ai_res)
609 TRACE(1, ("gai_test_callback context %p error rescode %d %s serv %s\n",
610 context, rescode, name, service));
613 while (!rescode && NULL != ai_res) {
615 memcpy(&addr, ai_res->ai_addr, ai_res->ai_addrlen);
616 TRACE(1, ("ctx %p fam %d addr %s canon '%s' type %s at %p ai_addr %p ai_next %p\n",
620 (ai_res->ai_canonname)
621 ? ai_res->ai_canonname
623 (SOCK_DGRAM == ai_res->ai_socktype)
625 : (SOCK_STREAM == ai_res->ai_socktype)
632 getnameinfo_sometime((sockaddr_u *)ai_res->ai_addr, 128, 32, 0, gni_test_callback, context);
634 ai_res = ai_res->ai_next;
637 #endif /* TEST_BLOCKING_WORKER */
641 getnameinfo_sometime(
646 gni_sometime_callback callback,
650 blocking_gni_req * gni_req;
652 dnschild_ctx * child_ctx;
656 REQUIRE(hostoctets + servoctets < 1024);
658 idx = get_dnschild_ctx();
659 child_ctx = dnschild_contexts[idx];
661 gni_req = emalloc_zero(sizeof(*gni_req));
663 gni_req->octets = sizeof(*gni_req);
664 gni_req->dns_idx = idx;
665 time_now = time(NULL);
666 gni_req->scheduled = time_now;
667 gni_req->earliest = max(time_now, child_ctx->next_dns_timeslot);
668 child_ctx->next_dns_timeslot = gni_req->earliest;
669 memcpy(&gni_req->socku, psau, SOCKLEN(psau));
670 gni_req->hostoctets = hostoctets;
671 gni_req->servoctets = servoctets;
672 gni_req->flags = flags;
673 gni_req->retry = INITIAL_DNS_RETRY;
674 gni_req->callback = callback;
675 gni_req->context = context;
677 if (queue_blocking_request(
678 BLOCKING_GETNAMEINFO,
681 &getnameinfo_sometime_complete,
684 msyslog(LOG_ERR, "unable to queue getnameinfo request");
694 blocking_getnameinfo(
696 blocking_pipe_header * req
699 blocking_gni_req * gni_req;
700 dnsworker_ctx * worker_ctx;
701 blocking_pipe_header * resp;
702 blocking_gni_resp * gni_resp;
711 gni_req = (void *)((char *)req + sizeof(*req));
713 octets = gni_req->hostoctets + gni_req->servoctets;
716 * Some alloca() implementations are fragile regarding
717 * large allocations. We only need room for the host
720 REQUIRE(octets < sizeof(host));
721 service = host + gni_req->hostoctets;
723 worker_ctx = get_worker_context(c, gni_req->dns_idx);
724 scheduled_sleep(gni_req->scheduled, gni_req->earliest,
726 reload_resolv_conf(worker_ctx);
729 * Take a shot at the final size, better to overestimate
730 * then realloc to a smaller size.
733 resp_octets = sizeof(*resp) + sizeof(*gni_resp) + octets;
734 resp = emalloc_zero(resp_octets);
735 gni_resp = (void *)((char *)resp + sizeof(*resp));
737 TRACE(2, ("blocking_getnameinfo given addr %s flags 0x%x hostlen %lu servlen %lu\n",
738 stoa(&gni_req->socku), gni_req->flags,
739 (u_long)gni_req->hostoctets, (u_long)gni_req->servoctets));
741 gni_resp->retcode = getnameinfo(&gni_req->socku.sa,
742 SOCKLEN(&gni_req->socku),
748 gni_resp->retry = gni_req->retry;
750 if (EAI_SYSTEM == gni_resp->retcode)
751 gni_resp->gni_errno = errno;
754 if (0 != gni_resp->retcode) {
755 gni_resp->hostoctets = 0;
756 gni_resp->servoctets = 0;
758 gni_resp->hostoctets = strlen(host) + 1;
759 gni_resp->servoctets = strlen(service) + 1;
761 * If this query succeeded only after retrying, DNS may have
762 * just become responsive. Ignore previously-scheduled
763 * retry sleeps once for each pending request, similar to
764 * the way scheduled_sleep() does when its worker_sleep()
767 if (gni_req->retry > INITIAL_DNS_RETRY) {
768 time_now = time(NULL);
769 worker_ctx->ignore_scheduled_before = time_now;
770 TRACE(1, ("DNS success after retrying, ignoring sleeps scheduled before now (%s)\n",
771 humantime(time_now)));
774 octets = gni_resp->hostoctets + gni_resp->servoctets;
776 * Our response consists of a header, followed by the host and
777 * service strings, each null-terminated.
779 resp_octets = sizeof(*resp) + sizeof(*gni_resp) + octets;
781 resp = erealloc(resp, resp_octets);
782 gni_resp = (void *)(resp + 1);
784 gni_resp->octets = sizeof(*gni_resp) + octets;
786 /* cp serves as our current pointer while serializing */
787 cp = (void *)(gni_resp + 1);
789 if (0 == gni_resp->retcode) {
790 memcpy(cp, host, gni_resp->hostoctets);
791 cp += gni_resp->hostoctets;
792 memcpy(cp, service, gni_resp->servoctets);
793 cp += gni_resp->servoctets;
796 INSIST((size_t)(cp - (char *)resp) == resp_octets);
797 INSIST(resp_octets - sizeof(*resp) == gni_resp->octets);
799 rc = queue_blocking_response(c, resp, resp_octets, req);
801 msyslog(LOG_ERR, "blocking_getnameinfo unable to queue response");
807 getnameinfo_sometime_complete(
808 blocking_work_req rtype,
814 blocking_gni_req * gni_req;
815 blocking_gni_resp * gni_resp;
816 dnschild_ctx * child_ctx;
825 DEBUG_REQUIRE(BLOCKING_GETNAMEINFO == rtype);
826 DEBUG_REQUIRE(respsize == gni_resp->octets);
828 child_ctx = dnschild_contexts[gni_req->dns_idx];
830 if (0 == gni_resp->retcode) {
832 * If this query succeeded only after retrying, DNS may have
833 * just become responsive.
835 if (gni_resp->retry > INITIAL_DNS_RETRY) {
836 time_now = time(NULL);
837 child_ctx->next_dns_timeslot = time_now;
838 TRACE(1, ("DNS success after retry, %u next_dns_timeslot reset (%s)\n",
839 gni_req->dns_idx, humantime(time_now)));
842 again = should_retry_dns(gni_resp->retcode, gni_resp->gni_errno);
844 * exponential backoff of DNS retries to 64s
846 if (gni_req->retry > 0)
847 manage_dns_retry_interval(&gni_req->scheduled,
848 &gni_req->earliest, &gni_req->retry,
849 &child_ctx->next_dns_timeslot, FALSE);
851 if (gni_req->retry > 0 && again) {
852 if (!queue_blocking_request(
853 BLOCKING_GETNAMEINFO,
856 &getnameinfo_sometime_complete,
860 msyslog(LOG_ERR, "unable to retry reverse lookup of %s", stoa(&gni_req->socku));
864 if (!gni_resp->hostoctets) {
868 host = (char *)gni_resp + sizeof(*gni_resp);
869 service = (gni_resp->servoctets)
870 ? host + gni_resp->hostoctets
874 (*gni_req->callback)(gni_resp->retcode, gni_resp->gni_errno,
875 &gni_req->socku, gni_req->flags, host,
876 service, gni_req->context);
879 /* gni_resp is part of block freed by process_blocking_resp() */
883 #ifdef TEST_BLOCKING_WORKER
884 void gni_test_callback(int rescode, int gni_errno, sockaddr_u *psau, int flags, const char *host, const char *service, void *context)
887 TRACE(1, ("gni_test_callback got host '%s' serv '%s' for addr %s context %p\n",
888 host, service, stoa(psau), context));
890 TRACE(1, ("gni_test_callback context %p rescode %d gni_errno %d flags 0x%x addr %s\n",
891 context, rescode, gni_errno, flags, stoa(psau)));
893 #endif /* TEST_BLOCKING_WORKER */
899 dnsworker_ctx * worker_ctx
905 * This is ad-hoc. Reload /etc/resolv.conf once per minute
906 * to pick up on changes from the DHCP client. [Bug 1226]
907 * When using threads for the workers, this needs to happen
908 * only once per minute process-wide.
910 time_now = time(NULL);
912 worker_ctx->next_res_init = next_res_init;
914 if (worker_ctx->next_res_init <= time_now) {
915 if (worker_ctx->next_res_init != 0)
917 worker_ctx->next_res_init = time_now + 60;
919 next_res_init = worker_ctx->next_res_init;
923 #endif /* HAVE_RES_INIT */
927 reserve_dnschild_ctx(void)
929 const size_t ps = sizeof(dnschild_contexts[0]);
930 const size_t cs = sizeof(*dnschild_contexts[0]);
938 for ( ; c < dnschild_contexts_alloc; c++) {
939 if (NULL == dnschild_contexts[c]) {
940 dnschild_contexts[c] = emalloc_zero(cs);
945 new_alloc = dnschild_contexts_alloc + 20;
946 new_octets = new_alloc * ps;
947 octets = dnschild_contexts_alloc * ps;
948 dnschild_contexts = erealloc_zero(dnschild_contexts,
950 dnschild_contexts_alloc = new_alloc;
956 get_dnschild_ctx(void)
958 static u_int shared_ctx = UINT_MAX;
960 if (worker_per_query)
961 return reserve_dnschild_ctx();
963 if (UINT_MAX == shared_ctx)
964 shared_ctx = reserve_dnschild_ctx();
970 static dnsworker_ctx *
980 dnsworker_ctx * retv;
982 worker_global_lock(TRUE);
984 if (dnsworker_contexts_alloc <= idx) {
985 min_new_alloc = 1 + idx;
986 /* round new_alloc up to nearest multiple of 4 */
987 new_alloc = (min_new_alloc + 4) & ~(4 - 1);
988 new_octets = new_alloc * sizeof(dnsworker_ctx*);
989 octets = dnsworker_contexts_alloc * sizeof(dnsworker_ctx*);
990 dnsworker_contexts = erealloc_zero(dnsworker_contexts,
992 dnsworker_contexts_alloc = new_alloc;
993 retv = emalloc_zero(sizeof(dnsworker_ctx));
994 dnsworker_contexts[idx] = retv;
995 } else if (NULL == (retv = dnsworker_contexts[idx])) {
996 retv = emalloc_zero(sizeof(dnsworker_ctx));
997 dnsworker_contexts[idx] = retv;
1000 worker_global_lock(FALSE);
1012 dnsworker_ctx * worker_ctx
1017 if (scheduled < worker_ctx->ignore_scheduled_before) {
1018 TRACE(1, ("ignoring sleep until %s scheduled at %s (before %s)\n",
1019 humantime(earliest), humantime(scheduled),
1020 humantime(worker_ctx->ignore_scheduled_before)));
1026 if (now < earliest) {
1027 TRACE(1, ("sleep until %s scheduled at %s (>= %s)\n",
1028 humantime(earliest), humantime(scheduled),
1029 humantime(worker_ctx->ignore_scheduled_before)));
1030 if (-1 == worker_sleep(worker_ctx->c, earliest - now)) {
1031 /* our sleep was interrupted */
1033 worker_ctx->ignore_scheduled_before = now;
1034 #ifdef HAVE_RES_INIT
1035 worker_ctx->next_res_init = now + 60;
1036 next_res_init = worker_ctx->next_res_init;
1039 TRACE(1, ("sleep interrupted by daemon, ignoring sleeps scheduled before now (%s)\n",
1040 humantime(worker_ctx->ignore_scheduled_before)));
1047 * manage_dns_retry_interval is a helper used by
1048 * getaddrinfo_sometime_complete and getnameinfo_sometime_complete
1049 * to calculate the new retry interval and schedule the next query.
1052 manage_dns_retry_interval(
1053 time_t * pscheduled,
1056 time_t * pnext_timeslot,
1067 when = max(now + retry, *pnext_timeslot);
1068 *pnext_timeslot = when;
1070 /* this exponential backoff is slower than doubling up: The
1071 * sequence goes 2-3-4-6-8-12-16-24-32... and the upper limit is
1072 * 64 seconds for things that should not repeat forever, and
1073 * 1024 when repeated forever.
1075 retmax = forever ? 1024 : 64;
1077 if (retry & (retry - 1))
1078 retry &= (retry - 1);
1080 retry -= (retry >> 2);
1081 retry = min(retmax, retry);
1089 * should_retry_dns is a helper used by getaddrinfo_sometime_complete
1090 * and getnameinfo_sometime_complete which implements ntpd's DNS retry
1099 static int eai_again_seen;
1101 #if defined (EAI_SYSTEM) && defined(DEBUG)
1106 * If the resolver failed, see if the failure is
1107 * temporary. If so, return success.
1119 eai_again_seen = 1; /* [Bug 1178] */
1123 #if defined(EAI_NODATA) && (EAI_NODATA != EAI_NONAME)
1126 again = !eai_again_seen; /* [Bug 1178] */
1132 * EAI_SYSTEM means the real error is in errno. We should be more
1133 * discriminating about which errno values require retrying, but
1134 * this matches existing behavior.
1138 errno_to_str(res_errno, msg, sizeof(msg));
1139 TRACE(1, ("intres: EAI_SYSTEM errno %d (%s) means try again, right?\n",
1146 TRACE(2, ("intres: resolver returned: %s (%d), %sretrying\n",
1147 gai_strerror(rescode), rescode, again ? "" : "not "));
1152 #else /* !WORKER follows */
1153 int ntp_intres_nonempty_compilation_unit;