Connectivity03

Status: Final

Purpose

• Evaluate ASN diversity of authoritative nameserver IP addresses.
• Classify IPv4 and IPv6 ASN diversity independently.

Preconditions And Inputs

• Preconditions:
  • A zone.Zone object is available.
  • A recursor is available on the zone object.
• Required inputs:
  • Nameserver addresses from ZoneNameservers .
  • ASN lookup results per unique IP address from asnlookup.GetWithPrefix.
• Profile/config knobs that affect behavior:
  • resolver.defaults.parallel: parallel ASN lookup fan-out.
  • asn_db.style and asn_db.sources: choose lookup backend/source list.

Algorithm And Decision Flow

1. Emit TEST_CASE_START.
2. Resolve nameserver list from ZoneNameservers .
3. Split into unique IPv4 and unique IPv6 IP lists (deduplicated by IP string).
4. For each unique IP (parallelized by family):
   • Run ASN lookup (lookupASN).
   • If result code is ERROR_ASN_DATABASE or EMPTY_ASN_SET, emit that tag with ns_ip and stop processing for that IP.
   • If raw lookup text exists, emit ASN_INFOS_RAW (ns_ip, data).
   • If ASN list exists, emit ASN_INFOS_ANNOUNCE_BY (ns_ip, asns) and store ASN set for diversity classification.
   • If prefix exists, emit ASN_INFOS_ANNOUNCE_IN (ns_ip, prefixes).
5. For IPv4 stored ASN data:
   • If no ASN values were stored, emit no IPv4 diversity summary tag.
   • If exactly one unique ASN exists, emit IPV4_ONE_ASN.
   • Else if all IPv4 IPs with ASN data share the same ASN-set signature, emit IPV4_SAME_ASN.
   • Else emit IPV4_DIFFERENT_ASN.
6. Repeat step 5 for IPv6 (IPV6_ONE_ASN, IPV6_SAME_ASN, IPV6_DIFFERENT_ASN).
7. Emit TEST_CASE_END.

Per-IP ASN Lookup (step 4)

resolve NS list with ZoneNameservers
 +- split unique IPs per family (dedupe by IP string):
      v4ips, v6ips

Per family, run tasks in parallel (fan-out = max(resolver.defaults.parallel, 1)):

   For each IP:
     lookupASN(rec, ip)
      +- res.Code == CodeError  -> ERROR_ASN_DATABASE  (address); stop this IP
      +- res.Code == CodeEmpty  -> EMPTY_ASN_SET       (address); stop this IP
      +- res.Raw non-empty      -> ASN_INFOS_RAW       (address, data)
      +- len(res.ASNs) > 0      -> ASN_INFOS_ANNOUNCE_BY (address, asns)
      |                            record asnset signature for this IP/family
      +- res.Prefix != nil      -> ASN_INFOS_ANNOUNCE_IN (address, prefixes)

Per-Family Diversity Classification (steps 5-6)

After per-IP lookups:
  v4asns    = sorted-unique ASNs across IPv4 IPs that returned ANNOUNCE_BY
  v4asnsets = sorted-unique ASN-set signatures across the same IPs
  (v6asns, v6asnsets defined the same way for IPv6)

IPv4:
  v4asns empty                 -> (no IPv4 summary)
  len(v4asns) == 1             -> IPV4_ONE_ASN       (asn)
  len(v4asnsets) == 1          -> IPV4_SAME_ASN      (asns)
  otherwise                    -> IPV4_DIFFERENT_ASN (asns)

IPv6 (same shape):
  v6asns empty                 -> (no IPv6 summary)
  len(v6asns) == 1             -> IPV6_ONE_ASN       (asn)
  len(v6asnsets) == 1          -> IPV6_SAME_ASN      (asns)
  otherwise                    -> IPV6_DIFFERENT_ASN (asns)

emit TEST_CASE_END

Emitted Tags (Possible Set)

Tag Arguments

Severity Levels Per Tag

Differences From Upstream

• Differences (Upstream vs Gonemaster):
  • Upstream: does not explicitly define this detail. Gonemaster: emits additional per-IP debug observability tags (ASN_INFOS_RAW, ASN_INFOS_ANNOUNCE_BY, ASN_INFOS_ANNOUNCE_IN).
  • Upstream: does not explicitly define this detail. Gonemaster: Diversity summary tags are computed from IPs that returned ASN data; IPs with EMPTY_ASN_SET/ERROR_ASN_DATABASE do not contribute ASN values to summary classification.
• Potential upstream report:
  • no

Edge Cases And Limitations

• If no IPs exist for a family, that family emits no diversity summary tag.
• If all lookups in a family fail or return empty ASN sets, that family emits only error/empty tags and no diversity summary tag.
• Per-IP ASN lookup tasks run in parallel, but emitted entry ordering is deterministic relative to input order.