axfr: split multi-mesage responses to 16kib -- compression

diff --git a/src/knot/nameserver/axfr.c b/src/knot/nameserver/axfr.c
index a96f6d6d213e0c2a294c457587c0af55d8831bd2..410db295987e2976dcfefc992adbb7e47a185d55 100644 (file)
--- a/src/knot/nameserver/axfr.c
+++ b/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;