#0  DNS_PACKET_SHALL_CACHE () at ../src/resolve/resolved-dns-packet.h:211
  206: static inline bool DNS_PACKET_SHALL_CACHE(DnsPacket *p) {
  207:         /* Never cache data originating from localhost, under the
  208:          * assumption, that it's coming from a locally DNS forwarder
  209:          * or server, that is caching on its own. */
  210: 
  211:         return in_addr_is_localhost(p->family, &p->sender) == 0;
  212: }
  213: 
  214: /* https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6 */
  215: enum {
  216:         DNS_RCODE_SUCCESS = 0,
#1  dns_transaction_cache_answer (t=0x55d99b3b48e0) at ../src/resolve/resolved-dns-transaction.c:582
  577: 
  578:         /* We never cache if this packet is from the local host, under
  579:          * the assumption that a locally running DNS server would
  580:          * cache this anyway, and probably knows better when to flush
  581:          * the cache then we could. */
  582:         if (!DNS_PACKET_SHALL_CACHE(t->received))
  583:                 return;
  584: 
  585:         dns_cache_put(&t->scope->cache,
  586:                       t->key,
  587:                       t->answer_rcode,
#2  dns_transaction_process_dnssec.lto_priv.425 (t=0x55d99b3b48e0) at ../src/resolve/resolved-dns-transaction.c:717
  712:         }
  713: 
  714:         if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER)
  715:                 dns_server_warn_downgrade(t->server);
  716: 
  717:         dns_transaction_cache_answer(t);
  718: 
  719:         if (t->answer_rcode == DNS_RCODE_SUCCESS)
  720:                 dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
  721:         else
  722:                 dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE);
#3  0x000055d99a2bf84c in dns_transaction_notify (source=0x55d99b3b71b0, t=0x55d99b3b48e0) at ../src/resolve/resolved-dns-transaction.c:2099
  2094:         /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
  2095:            we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
  2096:            the state is VALIDATING however, we should check if we are complete now. */
  2097: 
  2098:         if (t->state == DNS_TRANSACTION_VALIDATING)
  2099:                 dns_transaction_process_dnssec(t);
  2100: }
  2101: 
  2102: static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) {
  2103:         DnsResourceRecord *rr;
  2104:         int ifindex, r;
#4  dns_transaction_complete (t=0x55d99b3b71b0, state=<optimized out>) at ../src/resolve/resolved-dns-transaction.c:361
  356:         SET_FOREACH_MOVE(z, t->notify_zone_items_done, t->notify_zone_items)
  357:                 dns_zone_item_notify(z);
  358:         SWAP_TWO(t->notify_zone_items, t->notify_zone_items_done);
  359: 
  360:         SET_FOREACH_MOVE(d, t->notify_transactions_done, t->notify_transactions)
  361:                 dns_transaction_notify(d, t);
  362:         SWAP_TWO(t->notify_transactions, t->notify_transactions_done);
  363: 
  364:         t->block_gc--;
  365:         dns_transaction_gc(t);
  366: }
#5  0x000055d99a2c6cbd in dns_transaction_process_dnssec.lto_priv.425 (t=t@entry=0x55d99b3b71b0) at ../src/resolve/resolved-dns-transaction.c:720
  715:                 dns_server_warn_downgrade(t->server);
  716: 
  717:         dns_transaction_cache_answer(t);
  718: 
  719:         if (t->answer_rcode == DNS_RCODE_SUCCESS)
  720:                 dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
  721:         else
  722:                 dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE);
  723: 
  724:         return;
  725: 
#6  0x000055d99a2c7647 in dns_transaction_process_reply (t=t@entry=0x55d99b3b71b0, p=p@entry=0x55d99b3b8490) at ../src/resolve/resolved-dns-transaction.c:1002
   997:                         dns_transaction_stop_timeout(t);
   998:                         return;
   999:                 }
  1000:         }
  1001: 
  1002:         dns_transaction_process_dnssec(t);
  1003:         return;
  1004: 
  1005: fail:
  1006:         t->answer_errno = -r;
  1007:         dns_transaction_complete(t, DNS_TRANSACTION_ERRNO);
#7  0x000055d99a2c845b in on_dns_packet (s=<optimized out>, fd=<optimized out>, revents=<optimized out>, userdata=0x55d99b3b71b0) at ../src/resolve/resolved-dns-transaction.c:1053
  1048:         if (DNS_PACKET_ID(p) != t->id) {
  1049:                 log_debug("Received packet with incorrect transaction ID, ignoring.");
  1050:                 return 0;
  1051:         }
  1052: 
  1053:         dns_transaction_process_reply(t, p);
  1054:         return 0;
  1055: }
  1056: 
  1057: static int dns_transaction_emit_udp(DnsTransaction *t) {
  1058:         int r;
#8  0x000055d99a302563 in source_dispatch.lto_priv.501 (s=0x55d99b3b82b0) at ../src/libsystemd/sd-event/sd-event.c:2268
  2263:         s->dispatching = true;
  2264: 
  2265:         switch (s->type) {
  2266: 
  2267:         case SOURCE_IO:
  2268:                 r = s->io.callback(s, s->io.fd, s->io.revents, s->userdata);
  2269:                 break;
  2270: 
  2271:         case SOURCE_TIME_REALTIME:
  2272:         case SOURCE_TIME_BOOTTIME:
  2273:         case SOURCE_TIME_MONOTONIC:
#9  0x000055d99a29d7fc in sd_event_dispatch (e=0x55d99b39b1d0) at ../src/libsystemd/sd-event/sd-event.c:2629
  2624:         p = event_next_pending(e);
  2625:         if (p) {
  2626:                 sd_event_ref(e);
  2627: 
  2628:                 e->state = SD_EVENT_RUNNING;
  2629:                 r = source_dispatch(p);
  2630:                 e->state = SD_EVENT_INITIAL;
  2631: 
  2632:                 sd_event_unref(e);
  2633: 
  2634:                 return r;
#10 sd_event_run (timeout=18446744073709551615, e=0x55d99b39b1d0) at ../src/libsystemd/sd-event/sd-event.c:2688
  2683:         if (e->profile_delays)
  2684:                 e->last_run = now(CLOCK_MONOTONIC);
  2685: 
  2686:         if (r > 0) {
  2687:                 /* There's something now, then let's dispatch it */
  2688:                 r = sd_event_dispatch(e);
  2689:                 if (r < 0)
  2690:                         return r;
  2691: 
  2692:                 return 1;
  2693:         }
#11 sd_event_loop (e=0x55d99b39b1d0) at ../src/libsystemd/sd-event/sd-event.c:2708
  2703:         assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
  2704: 
  2705:         sd_event_ref(e);
  2706: 
  2707:         while (e->state != SD_EVENT_FINISHED) {
  2708:                 r = sd_event_run(e, (uint64_t) -1);
  2709:                 if (r < 0)
  2710:                         goto finish;
  2711:         }
  2712: 
  2713:         r = e->exit_code;
#12 main (argc=<optimized out>, argv=<optimized out>) at ../src/resolve/resolved.c:98
   93: 
   94:         sd_notify(false,
   95:                   "READY=1\n"
   96:                   "STATUS=Processing requests...");
   97: 
   98:         r = sd_event_loop(m->event);
   99:         if (r < 0) {
  100:                 log_error_errno(r, "Event loop failed: %m");
  101:                 goto finish;
  102:         }
  103: