Module: OpenASN::Classifier

Defined in:
lib/openasn/classifier.rb

Overview

The verdict precedence ladder. First match wins. This ordering IS the product — change it only with the data repo's DECISIONS.md open next to you, because every line encodes a documented false-positive lesson:

1. invalid input                       -> InvalidIPError (raised in IP.parse)
2. special ranges                      -> :private / :cgnat
3. relay overlays (Tier B: Apple)      -> :relay
4. tor overlays (Tier B)               -> :tor_exit
5. vpn ranges (canonical X4B ∪ Tier B provider lists) -> :vpn
6. ASN flag vpn_provider               -> :vpn
7. ASN flag enterprise_gw ∪ Tier B gateway ranges -> :enterprise_gateway
8. cloud provider ranges (Tier B)      -> :hosting (provider tagged)
9. canonical dc overlay (X4B)          -> :hosting
10. flags bad_asn|hosting_extra|cdn or category==hosting -> :hosting
11. ASN flag mobile_carrier             -> :mobile
12. category isp, role != tier1_transit -> :residential_isp
13. category business                   -> :business
14. category education_research         -> :education
15. category government_admin           -> :government
16. category isp + tier1_transit        -> :unknown (pure-backbone ambiguity)
17. ASN found, no category              -> :unknown
18. no ASN                              -> :unknown (unrouted)

Why relay outranks EVERYTHING data-driven: iCloud Private Relay egress lives inside Cloudflare/Akamai space, which the base layer correctly calls hosting — paying iCloud+ customers would classify as datacenter traffic without rule 3. Same defensive logic for enterprise gateways (rule 7 beats the hosting rules: Zscaler ranges are offices, not servers). Rules 12/16: see the data repo's DECISIONS.md D-IMPL-1 — every national telco carries a transit role in upstream data; only pure tier-1 backbone is genuinely ambiguous.

Class Method Summary collapse

Class Method Details

.classify(snapshot, ip_input) ⇒ Object 



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# File 'lib/openasn/classifier.rb', line 38

def classify(snapshot, ip_input)
  family, ip_int = IP.parse(ip_input)
  ip_string = ip_input.is_a?(String) ? ip_input : ip_input.to_s

  # Rule 2 — specials don't need data at all.
  if (special = SpecialRanges.match(ip_int, family))
    return Result.new(ip: ip_string, verdict: special[0], sources: [special[1]])
  end

  layers = snapshot.family(family)

  # The base layer is consulted regardless of the winning rule: even a
  # Tor exit's Result should say which ASN announces it.
  asn, flags = layers.base.find(ip_int)
  flags ||= 0
  category = BinaryFormat.category_name(flags)
  role = BinaryFormat.role_name(flags)

  # Context flags never decide verdicts; they ride along for app logic.
  context = []
  snapshot.overlays_for(family, "flag:cloudflare_range").each do |(_, layer)|
    context << :cloudflare_range if layer.cover?(ip_int)
  end
  snapshot.overlays_for(family, "flag:mixed_high_risk").each do |(_, layer)|
    context << :mixed_high_risk if layer.cover?(ip_int)
  end

  verdict, provider, sources = decide(snapshot, layers, family, ip_int, flags, category, role, asn)

  Result.new(
    ip: ip_string, verdict: verdict, asn: asn,
    as_org: snapshot.org_name(asn), category: category, network_role: role,
    provider: provider, sources: sources, flags: flags,
    context_flags: context, unrouted: asn.nil?
  )
end

.decide(snapshot, layers, family, ip_int, flags, category, role, asn) ⇒ Object

rubocop:disable Metrics



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# File 'lib/openasn/classifier.rb', line 75

def decide(snapshot, layers, family, ip_int, flags, category, role, asn) # rubocop:disable Metrics
  # 3 — relay
  if (hit = overlay_hit(snapshot, family, "relay", ip_int))
    return [:relay, hit.provider, [hit.id.to_sym]]
  end

  # 4 — tor
  if (hit = overlay_hit(snapshot, family, "tor_exit", ip_int))
    return [:tor_exit, hit.provider, [hit.id.to_sym]]
  end

  # 5 — vpn ranges. Provider-attributed Tier B lists are consulted
  # BEFORE the anonymous canonical overlay on purpose: when both match
  # (common — X4B covers most VPN hosting space), the verdict is
  # identical but "ProtonVPN" beats provider=nil for explainability.
  if (hit = overlay_hit(snapshot, family, "vpn", ip_int))
    return [:vpn, hit.provider, [hit.id.to_sym]]
  end

  return [:vpn, nil, [:x4b_vpn]] if layers.vpn.cover?(ip_int)

  # 6 — vpn by ASN flag
  return [:vpn, nil, [:asn_vpn_provider]] if flags.anybits?(BinaryFormat::FLAG_VPN_PROVIDER)

  # 7 — enterprise gateway (flag, then Tier B ranges)
  return [:enterprise_gateway, nil, [:asn_enterprise_gw]] if flags.anybits?(BinaryFormat::FLAG_ENTERPRISE_GW)

  if (hit = overlay_hit(snapshot, family, "enterprise_gateway", ip_int))
    return [:enterprise_gateway, hit.provider, [hit.id.to_sym]]
  end

  # 8 — cloud provider ranges (provider attribution is the value-add)
  if (hit = overlay_hit(snapshot, family, "hosting", ip_int))
    return [:hosting, hit.provider, [hit.id.to_sym]]
  end

  # 9 — canonical datacenter overlay
  return [:hosting, nil, [:x4b_dc]] if layers.dc.cover?(ip_int)

  # 10 — hosting by ASN signal
  if flags.anybits?(BinaryFormat::FLAG_BAD_ASN | BinaryFormat::FLAG_HOSTING_EXTRA | BinaryFormat::FLAG_CDN) ||
     category == "hosting"
    return [:hosting, nil, hosting_sources(flags, category)]
  end

  # 11 — mobile
  return [:mobile, nil, [:asn_mobile_carrier]] if flags.anybits?(BinaryFormat::FLAG_MOBILE)

  # 12–17 — category ladder
  if category == "isp"
    return role == "tier1_transit" ? [:unknown, nil, [:isp_transit_ambiguous]] : [:residential_isp, nil, [:asn_category]]
  end
  return [:business, nil, [:asn_category]]   if category == "business"
  return [:education, nil, [:asn_category]]  if category == "education_research"
  return [:government, nil, [:asn_category]] if category == "government_admin"
  return [:unknown, nil, [:asn_no_category]] if asn

  # 18 — unrouted
  [:unknown, nil, [:unrouted]]
end

.hosting_sources(flags, category) ⇒ Object 



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# File 'lib/openasn/classifier.rb', line 143

def hosting_sources(flags, category)
  sources = []
  sources << :asn_bad_asn       if flags.anybits?(BinaryFormat::FLAG_BAD_ASN)
  sources << :asn_hosting_extra if flags.anybits?(BinaryFormat::FLAG_HOSTING_EXTRA)
  sources << :asn_cdn           if flags.anybits?(BinaryFormat::FLAG_CDN)
  sources << :asn_category      if category == "hosting"
  sources
end

.overlay_hit(snapshot, family, maps_to, ip_int) ⇒ Object 



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# File 'lib/openasn/classifier.rb', line 136

def overlay_hit(snapshot, family, maps_to, ip_int)
  snapshot.overlays_for(family, maps_to).each do |(entry, layer)|
    return entry if layer.cover?(ip_int)
  end
  nil
end