BIND 10 #2564: MasterLoader needs to perform minimal validation for SOA

[BIND 10 Development]

#2564: MasterLoader needs to perform minimal validation for SOA
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                   Reporter:         |                 Owner:
  jinmei                             |                Status:  new
                       Type:  task   |             Milestone:  Next-Sprint-
                   Priority:         |  Proposed
  medium                             |              Keywords:
                  Component:         |             Sensitive:  0
  Unclassified                       |           Sub-Project:  DNS
               CVSS Scoring:         |  Estimated Difficulty:  0
            Defect Severity:  N/A    |           Total Hours:  0
Feature Depending on Ticket:         |
  loadzone-ng                        |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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 It should do something equivalent to the following BIND 9 code:
 {{{#!c
                 if (type == dns_rdatatype_soa &&
                     (lctx->options & DNS_MASTER_ZONE) != 0 &&
                     dns_name_compare(ictx->current, lctx->top) != 0) {
                         char namebuf[DNS_NAME_FORMATSIZE];
                         dns_name_format(ictx->current, namebuf,
                                         sizeof(namebuf));
                         (*callbacks->error)(callbacks, "%s:%lu: SOA "
                                             "record not at top of zone
 (%s)",
                                             source, line, namebuf);
                         result = DNS_R_NOTZONETOP;
                         if (MANYERRS(lctx, result)) {
                                 SETRESULT(lctx, result);
                                 read_till_eol = ISC_TRUE;
                                 target = target_ft;
                                 continue;
                         } else if (result != ISC_R_SUCCESS)
                                 goto insist_and_cleanup;
                 }
 }}}

 i.e., reject "example.com/SOA" for the example.org zone.

 I intended to do it in #2377, but #2377 didn't address it.  Note that
 there's no other point that we can do this effectively, unless we
 require expensive whole-zone search in the post-load validation phase
 by default.

 As the BIND 9 code shows, we should also introduce a loader option
 that allows to skip this check.

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Ticket URL: <http://bind10.isc.org/ticket/2564>
BIND 10 Development <http://bind10.isc.org>
BIND 10 Development