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ntp: use async name resolving for NTP sources

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Use the new asynchronous call to resolve addresses of NTP servers
configured by the server/peer directives. Introduce a callback to be
notified when the first resolving attempt ends to correctly finish
chronyd initialization (dumpfile reload and reference mode end).
This commit is contained in:
Miroslav Lichvar
2014-04-25 16:58:21 +02:00
parent 779e40ed66
commit 6ee357d230
4 changed files with 133 additions and 49 deletions
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135
ntp_sources.c
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@@ -37,7 +37,7 @@
#include "logging.h"
#include "local.h"
#include "memory.h"
#include "nameserv.h"
#include "nameserv_async.h"
#include "sched.h"
/* ================================================== */
@@ -77,9 +77,14 @@ struct UnresolvedSource {
static struct UnresolvedSource *unresolved_sources = NULL;
static int resolving_interval = 0;
static SCH_TimeoutID resolving_id;
static struct UnresolvedSource *resolving_source = NULL;
static NSR_SourceResolvingEndHandler resolving_end_handler = NULL;
/* ================================================== */
/* Forward prototypes */
static void resolve_sources(void *arg);
static void
slew_sources(struct timeval *raw,
struct timeval *cooked,
@@ -218,42 +223,87 @@ NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourceParam
/* ================================================== */
static void
name_resolve_handler(DNS_Status status, IPAddr *ip_addr, void *anything)
{
struct UnresolvedSource *us, **i, *next;
NTP_Remote_Address address;
us = (struct UnresolvedSource *)anything;
assert(us == resolving_source);
switch (status) {
case DNS_TryAgain:
break;
case DNS_Success:
DEBUG_LOG(LOGF_NtpSources, "%s resolved to %s", us->name, UTI_IPToString(ip_addr));
address.ip_addr = *ip_addr;
address.port = us->port;
NSR_AddSource(&address, us->type, &us->params);
break;
case DNS_Failure:
LOG(LOGS_WARN, LOGF_NtpSources, "Invalid host %s", us->name);
break;
default:
assert(0);
}
next = us->next;
if (status != DNS_TryAgain) {
/* Remove the source from the list */
for (i = &unresolved_sources; *i; i = &(*i)->next) {
if (*i == us) {
*i = us->next;
Free(us->name);
Free(us);
break;
}
}
}
resolving_source = next;
if (next) {
/* Continue with the next source in the list */
DEBUG_LOG(LOGF_NtpSources, "resolving %s", next->name);
DNS_Name2IPAddressAsync(next->name, name_resolve_handler, next);
} else {
/* This was the last source in the list. If some sources couldn't
be resolved, try again in exponentially increasing interval. */
if (unresolved_sources) {
if (resolving_interval < 9)
resolving_interval++;
resolving_id = SCH_AddTimeoutByDelay(7 * (1 << resolving_interval), resolve_sources, NULL);
} else {
resolving_interval = 0;
}
/* This round of resolving is done */
if (resolving_end_handler)
(resolving_end_handler)();
}
}
/* ================================================== */
static void
resolve_sources(void *arg)
{
NTP_Remote_Address address;
struct UnresolvedSource *us, **i;
DNS_Status s;
struct UnresolvedSource *us;
assert(!resolving_source);
DNS_Reload();
for (i = &unresolved_sources; *i; ) {
us = *i;
s = DNS_Name2IPAddress(us->name, &address.ip_addr);
if (s == DNS_TryAgain) {
i = &(*i)->next;
continue;
} else if (s == DNS_Success) {
address.port = us->port;
NSR_AddSource(&address, us->type, &us->params);
} else {
LOG(LOGS_WARN, LOGF_NtpSources, "Invalid host %s", us->name);
}
*i = us->next;
/* Start with the first source in the list, name_resolve_handler
will iterate over the rest */
us = unresolved_sources;
Free(us->name);
Free(us);
}
if (unresolved_sources) {
/* Try again later */
if (resolving_interval < 9)
resolving_interval++;
resolving_id = SCH_AddTimeoutByDelay(7 * (1 << resolving_interval), resolve_sources, NULL);
} else {
resolving_interval = 0;
}
resolving_source = us;
DEBUG_LOG(LOGF_NtpSources, "resolving %s", us->name);
DNS_Name2IPAddressAsync(us->name, name_resolve_handler, us);
}
/* ================================================== */
@@ -285,14 +335,31 @@ NSR_AddUnresolvedSource(char *name, int port, NTP_Source_Type type, SourceParame
/* ================================================== */
void
NSR_SetSourceResolvingEndHandler(NSR_SourceResolvingEndHandler handler)
{
resolving_end_handler = handler;
}
/* ================================================== */
void
NSR_ResolveSources(void)
{
/* Try to resolve unresolved sources now */
if (resolving_interval) {
SCH_RemoveTimeout(resolving_id);
resolving_interval--;
resolve_sources(NULL);
if (unresolved_sources) {
/* Make sure no resolving is currently running */
if (!resolving_source) {
if (resolving_interval) {
SCH_RemoveTimeout(resolving_id);
resolving_interval--;
}
resolve_sources(NULL);
}
} else {
/* No unresolved sources, we are done */
if (resolving_end_handler)
(resolving_end_handler)();
}
}