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ferrix/docs/RFCs.md
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Rayhaan JaufeerallyandClaude Fable 5.1 8086aa994f Verify AS paths with ASPAs, over RTR version 2
Origin validation says who may originate a prefix and nothing about the
rest of the path: it does not catch a route leak, nor a hijack that keeps
the right origin at the end of a made-up path. ASPAs, in which a network
lists its providers, do.

bgp-rpki:
- aspa: the ASPAs and the upstream and downstream verification procedures
  of draft-ietf-sidrops-aspa-verification-24, tested against the draft's
  wording as written.
- rtr: protocol version 2 (draft-ietf-sidrops-8210bis-23) with the ASPA
  PDU and the new error codes.
- client: asks for version 2 and falls back to whatever older version the
  cache speaks; keeps ASPAs with the VRPs, applied whole or not at all;
  publishes which customers' ASPAs changed; tells the cache why it is
  being left (Error Report); does not ask one version's serial of another.

Server:
- A peer has a role (provider, customer, peer, route server, route server
  client), which decides how its paths are verified. Without one they are
  not.
- A route whose path is invalid is refused ("ASPA invalid") and held, like
  one with an invalid origin; accept_aspa_invalid exempts a peer.
- When ASPAs change, routes in the table whose path has a changed customer
  on it are verified again, and held routes are released when they pass
  both checks.
- The revalidator finds a route's peer by index instead of searching a
  list for every route.

The status page and API show each peer's role, each route's path validity,
the number of ASPAs and the RTR version in use; bgp_rpki_aspas is on
/metricz.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2026-10-02 14:12:59 +02:00

8.6 KiB

RFCs

Tracks which RFCs are implemented, partially implemented, or only represented in the wire format layer.

Legend

  • ✅ Implemented — functional end-to-end
  • 🟡 Wire format only — parsed and serialised correctly, but not yet acted on
  • ❌ Not implemented

Core BGP

RFC 4271 — A Border Gateway Protocol 4 (BGP-4)

https://datatracker.ietf.org/doc/html/rfc4271

The base protocol specification.

Section Description Status
§4.1 Message framing (marker, length, type) ✅
§4.2 OPEN message ✅
§4.3 UPDATE message (path attributes, NLRI, withdrawn routes) ✅
§4.4 KEEPALIVE message ✅
§4.5 NOTIFICATION message (all error codes and subcodes) ✅
§8 FSM — passive (inbound) side: OpenSent → OpenConfirm → Established ✅
§8 FSM — active (outbound) side: dial configured peers, exponential retry ✅
§6.2 Bad Peer AS check against configured ASN ✅
§6.7 / RFC 4486 Cease / Administrative Shutdown sent to every peer on SIGINT or SIGTERM ✅
§6.8 Connection collision detection (BGP Identifier comparison, Cease / Connection Collision Resolution) ✅
§8.1.1 Optional CollisionDetectEstablishedState (collision_detect_established_state) ✅
§6.2 Bad BGP Identifier check (peer using our identifier, or 0.0.0.0) ✅
§9 Decision process / best-path selection ❌
§9 Adj-RIB-In (per-peer table of received routes) ✅
§9 Locally originated routes, advertised to all established peers ✅
§9 Loc-RIB / Adj-RIB-Out for routes learned from peers (re-advertisement) ❌
§9.2 Hold timer reset on any received message (not only KEEPALIVE) ✅

Capability and Session Extensions

RFC 6793 — BGP Support for Four-Octet Autonomous System (AS) Number Space

https://datatracker.ietf.org/doc/html/rfc6793

Feature Status
AS_TRANS (23456) sentinel ✅
FourByteAsn capability advertisement and parsing ✅
4-byte AS_PATH segment encoding/decoding via ParserContext ✅
4-byte ASN negotiation in FSM ✅

RFC 9072 — Extended Optional Parameters Length for BGP OPEN Message

https://datatracker.ietf.org/doc/html/rfc9072

Feature Status
Parsing extended-length OPEN (0xFF sentinel) ✅
Serialising extended-length OPEN when options exceed 255 bytes ✅

RFC 2918 — Route Refresh Capability for BGP-4

https://datatracker.ietf.org/doc/html/rfc2918

Feature Status
RouteRefresh capability advertisement ✅
ROUTE-REFRESH message type (5) framing ✅
AFI/SAFI payload parsing ❌
Acting on received ROUTE-REFRESH (re-advertising all local routes, regardless of the AFI/SAFI asked for) ✅

RFC 7313 — Enhanced Route Refresh Capability for BGP-4

https://datatracker.ietf.org/doc/html/rfc7313

Feature Status
EnhancedRouteRefresh capability wire format 🟡

RFC 4724 — Graceful Restart Mechanism for BGP

https://datatracker.ietf.org/doc/html/rfc4724

Feature Status
GracefulRestart capability wire format 🟡
Restart state and forwarding preserved across sessions ❌

RFC 9494 — Long-Lived Graceful Restart for BGP

https://datatracker.ietf.org/doc/html/rfc9494

Feature Status
LongLivedGracefulRestart capability wire format 🟡

RFC 8654 — Extended Message Support for BGP

https://datatracker.ietf.org/doc/html/rfc8654

Feature Status
ExtendedMessage capability wire format 🟡
Raising BGP_MAX_MSG_LEN to 65535 when negotiated ❌

Multiprotocol and NLRI

RFC 2858 — Multiprotocol Extensions for BGP-4

https://datatracker.ietf.org/doc/html/rfc2858

Feature Status
MultiProtocol capability advertisement (IPv4 and IPv6 unicast) ✅
MP_REACH_NLRI path attribute (parse, serialise) ✅
MP_UNREACH_NLRI path attribute (parse, serialise) ✅
IPv4 and IPv6 next-hop encoding ✅

RFC 8950 — Advertising IPv4 Network Layer Reachability Information (NLRI) with an IPv6 Next Hop

https://datatracker.ietf.org/doc/html/rfc8950

Feature Status
ExtendedNextHop capability wire format 🟡

Path Attributes and Communities

RFC 1997 — BGP Communities Attribute

https://datatracker.ietf.org/doc/html/rfc1997

Feature Status
COMMUNITIES path attribute (parse, serialise) ✅
Attach to locally originated routes ✅

RFC 4360 — BGP Extended Communities Attribute

https://datatracker.ietf.org/doc/html/rfc4360

Feature Status
EXTENDED_COMMUNITIES path attribute (parse, serialise) ✅
AS-specific, IPv4-address-specific, opaque, route-target, route-origin subtypes ✅

RFC 8092 — BGP Large Communities Attribute

https://datatracker.ietf.org/doc/html/rfc8092

Feature Status
LARGE_COMMUNITIES path attribute (parse, serialise) ✅
Attach to locally originated routes ✅

Other Capabilities (Wire Format Only)

The following capabilities are parsed and serialised correctly but have no functional behaviour implemented beyond that.

RFC Capability Status
RFC 5291 Outbound Route Filtering (ORF) 🟡
RFC 8205 BGPsec 🟡

Error Handling

RFC 9687 — BGP Send Hold Timer

https://datatracker.ietf.org/doc/html/rfc9687

Feature Status
SendHoldTimer error code (8) defined ✅
Send hold timer enforcement (a write that makes no progress ends the session) ✅

Route Security

RFC 6811 — BGP Prefix Origin Validation

https://datatracker.ietf.org/doc/html/rfc6811

Feature Status
Validation states (valid, invalid, not found) for routes from external peers ✅
Invalid routes refused, per peer (accept_rpki_invalid to take them) ✅
Routes revalidated when the VRPs change, in both directions ✅
Validation of routes from internal peers and of originated routes ❌
Validity as a step of route selection (RFC 8097 communities) ❌

draft-ietf-sidrops-aspa-verification — BGP AS_PATH Verification Based on ASPA

https://datatracker.ietf.org/doc/draft-ietf-sidrops-aspa-verification/

Implemented from version 24 of the draft.

Feature Status
Upstream verification (routes from customers, peers, route servers and route server clients) ✅
Downstream verification (routes from providers) ✅
Per-peer role (role); paths of peers without one are not verified ✅
Invalid paths refused, per peer (accept_aspa_invalid to take them) ✅
Routes revalidated when the ASPAs change, in both directions ✅
Paths with an AS_SET invalid ✅
Verification on export ❌ (learned routes are not exported yet)
Roles negotiated in OPEN, Only-to-Customer attribute (RFC 9234) ❌

RFC 8210 — The RPKI to Router Protocol, Version 1 (RFC 6810, version 0; draft-ietf-sidrops-8210bis, version 2)

https://datatracker.ietf.org/doc/html/rfc8210

Version 2 is implemented from version 23 of the draft.

Feature Status
Reset and serial queries, notifies, cache reset, incremental updates ✅
Refresh, retry and expire intervals; data dropped when it expires ✅
Version 2, with fallback to 1 and 0; several caches with failover ✅
ASPA PDU (version 2) ✅
Error Reports sent to the cache ✅
Version 2's ordering of PDUs enforced on what a cache sends ❌ (any order is taken)
Transport over plain TCP ✅
Transport over SSH, TLS, TCP-MD5 or TCP-AO ❌
Router keys (BGPsec) 🟡 read and ignored

RFC 7911 — Advertisement of Multiple Paths in BGP (ADD-PATH)

https://datatracker.ietf.org/doc/html/rfc7911

Feature Status
Capability negotiation per family and direction ✅
Receiving several routes for a prefix ✅
Sending several routes for a prefix ❌ (path identifiers are sent; one route each)

RFC 4271 §9.1.2 / RFC 4486 / operational practice — import policy

Feature Status
Own AS in path refused (loop detection) ✅
Bogon prefixes and AS numbers, prefix length bounds, first-AS check ✅
Per-peer prefix and origin AS allow-lists ✅
Maximum prefixes with Cease / Maximum Number of Prefixes Reached and hold-down ✅