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resolve: fix misuse of accuracy parameter in sd_event_add_time()

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Also, this makes mDNS regular queries sent without delay (except for
one caused by the default accuracy of sd-event).

Note, RFC 6762 Section 5.2 is about continuous mDNS query, which is not
implemented yet.
This commit is contained in:
Yu Watanabe 2022-07-04 05:36:20 +09:00
parent 4b2ceb8a48
commit 765647ba80
3 changed files with 13 additions and 18 deletions
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10
src/resolve/resolved-dns-scope.c
View File

@ -1204,7 +1204,6 @@ static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata
}
int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
usec_t jitter;
int r;
assert(scope);
@ -1233,15 +1232,12 @@ int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
if (scope->conflict_event_source)
return 0;
random_bytes(&jitter, sizeof(jitter));
jitter %= LLMNR_JITTER_INTERVAL_USEC;
r = sd_event_add_time_relative(
scope->manager->event,
&scope->conflict_event_source,
CLOCK_BOOTTIME,
jitter,
LLMNR_JITTER_INTERVAL_USEC,
random_u64_range(LLMNR_JITTER_INTERVAL_USEC),
0,
on_conflict_dispatch, scope);
if (r < 0)
return log_debug_errno(r, "Failed to add conflict dispatch event: %m");
@ -1511,7 +1507,7 @@ int dns_scope_announce(DnsScope *scope, bool goodbye) {
&scope->announce_event_source,
CLOCK_BOOTTIME,
MDNS_ANNOUNCE_DELAY,
MDNS_JITTER_RANGE_USEC,
0,
on_announcement_timeout, scope);
if (r < 0)
return log_debug_errno(r, "Failed to schedule second announcement: %m");

17
src/resolve/resolved-dns-transaction.c
View File

@ -1951,10 +1951,12 @@ int dns_transaction_go(DnsTransaction *t) {
if (!t->initial_jitter_scheduled &&
IN_SET(t->scope->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) {
usec_t jitter, accuracy;
usec_t jitter;
/* RFC 4795 Section 2.7 suggests all queries should be delayed by a random time from 0 to
* JITTER_INTERVAL. */
/* RFC 4795 Section 2.7 suggests all LLMNR queries should be delayed by a random time from 0 to
* JITTER_INTERVAL.
* RFC 6762 Section 8.1 suggests initial probe queries should be delayed by a random time from
* 0 to 250ms. */
t->initial_jitter_scheduled = true;
@ -1962,12 +1964,13 @@ int dns_transaction_go(DnsTransaction *t) {
case DNS_PROTOCOL_LLMNR:
jitter = random_u64_range(LLMNR_JITTER_INTERVAL_USEC);
accuracy = LLMNR_JITTER_INTERVAL_USEC;
break;
case DNS_PROTOCOL_MDNS:
jitter = usec_add(random_u64_range(MDNS_JITTER_RANGE_USEC), MDNS_JITTER_MIN_USEC);
accuracy = MDNS_JITTER_RANGE_USEC;
if (t->probing)
jitter = random_u64_range(MDNS_PROBING_INTERVAL_USEC);
else
jitter = 0;
break;
default:
assert_not_reached();
@ -1979,7 +1982,7 @@ int dns_transaction_go(DnsTransaction *t) {
t->scope->manager->event,
&t->timeout_event_source,
CLOCK_BOOTTIME,
jitter, accuracy,
jitter, 0,
on_transaction_timeout, t);
if (r < 0)
return r;

4
src/resolve/resolved-dns-transaction.h
View File

@ -201,10 +201,6 @@ DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
/* LLMNR Jitter interval, see RFC 4795 Section 7 */
#define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
/* mDNS Jitter interval, see RFC 6762 Section 5.2 */
#define MDNS_JITTER_MIN_USEC (20 * USEC_PER_MSEC)
#define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
/* mDNS probing interval, see RFC 6762 Section 8.1 */
#define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)