diff options
Diffstat (limited to 'src/resolve/resolved-dns-transaction.c')
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 27 |
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 */ |