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-rw-r--r--src/resolve/resolved-dns-transaction.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index ad1b277555..53d6e18dc5 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -490,6 +490,33 @@ int dns_transaction_go(DnsTransaction *t) {
}
}
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR && !t->initial_jitter) {
+ usec_t jitter;
+
+ /* RFC 4795 Section 2.7 suggests all queries should be
+ * delayed by a random time from 0 to JITTER_INTERVAL. */
+
+ t->initial_jitter = true;
+
+ random_bytes(&jitter, sizeof(jitter));
+ jitter %= LLMNR_JITTER_INTERVAL_USEC;
+
+ r = sd_event_add_time(
+ t->scope->manager->event,
+ &t->timeout_event_source,
+ clock_boottime_or_monotonic(),
+ now(clock_boottime_or_monotonic()) + jitter, LLMNR_JITTER_INTERVAL_USEC,
+ on_transaction_timeout, t);
+ if (r < 0)
+ return r;
+
+ t->n_attempts = 0;
+ t->state = DNS_TRANSACTION_PENDING;
+
+ log_debug("Delaying LLMNR transaction for " USEC_FMT "us.", jitter);
+ return 0;
+ }
+
log_debug("Cache miss!");
/* Otherwise, we need to ask the network */