Merge branch 'axfr_16kib' into 'master'

Axfr 16kib

See merge request !1173

src/knot/nameserver/axfr.c

@@ -57,6 +57,12 @@ static int axfr_put_rrsets(knot_pkt_t *pkt, zone_node_t *node,
 			state->cur_rrset = i;
 			return ret;
 		}
+		if (pkt->size > KNOT_WIRE_PTR_MAX) {
+			// optimization: once the XFR DNS message is > 16 KiB, compression
+			// is limited. Better wrap to next message.
+			state->cur_rrset = i + 1;
+			return KNOT_ESPACE;
+		}
 	}
 
 	state->cur_rrset = 0;

src/knot/nameserver/ixfr.c

@@ -63,6 +63,13 @@ static int ixfr_put_chg_part(knot_pkt_t *pkt, struct ixfr_proc *ixfr,
 		    knot_soa_serial(ixfr->cur_rr.rrs.rdata) == ixfr->soa_to) {
 			break;
 		}
+
+		if (pkt->size > KNOT_WIRE_PTR_MAX) {
+			// optimization: once the XFR DNS message is > 16 KiB, compression
+			// is limited. Better wrap to next message.
+			return KNOT_ESPACE;
+		}
+
 		IXFR_SAFE_PUT(pkt, &ixfr->cur_rr);
 		if (ixfr->cur_rr.type == KNOT_RRTYPE_SOA) {
 			ixfr->in_remove_section = !ixfr->in_remove_section;