Zone size limit

#464 (closed) size limit for incoming zone transfer

• max-zone-size option is part of zone/template
• zone size is measured in uncompressed wire format

currently only IXFR and AXFR is used this limit, IXFR, AXFR and DDNS is limited.

Question: Should we limit zone size at all inputs to the server (file, ctl, ) ?

IXFR:

Counting size of incoming add and delete sections. Transfer fail when:

1. Actual zone size + add size - delete size > limit
2. add size + delete size > 2 * limit
3. size of new created zone > limit

doc/reference.rst

@@ -824,6 +824,7 @@ Definition of zones served by the server.
      zonefile-sync: TIME
      ixfr-from-differences: BOOL
      max-journal-size: SIZE
+     max-zone-size : SIZE
      dnssec-signing: BOOL
      dnssec-policy: STR
      kasp-db: STR
@@ -1007,6 +1008,21 @@ Maximum size of the zone journal file.
 
 *Default:* 2^64
 
+.. _zone_max_zone_size:
+
+max-zone-size
+----------------
+
+Maximum size of the zone. The size is measured as size of the zone records
+in wire format without compression. The limit is enforced for incoming zone
+transfers and dynamic updates.
+
+For incremental transfers (IXFR), the effective limit for the total size of
+the records in the transfer is twice the configured value. However the final
+size of the zone must satisfy the configured value.
+
+*Default:* 2^64
+
 .. _zone_dnssec-signing:
 
 dnssec-signing