rustbgpd-wire

BGP message codec for Rust. Encode and decode OPEN, UPDATE, KEEPALIVE, NOTIFICATION, and ROUTE-REFRESH messages per RFC 4271, with extensions for MP-BGP, EVPN (including PMSI Tunnel for ingress-replication BUM), FlowSpec, Add-Path, Extended Messages, and more.

This crate is the wire-protocol foundation of rustbgpd but is designed for standalone use in any Rust project that needs to parse or build BGP messages — monitors, analyzers, test harnesses, MRT readers, etc.

Supported RFCs

Usage

Decode a single BGP message from raw bytes:

use bytes::Bytes;
use rustbgpd_wire::{decode_message, encode_message, Message, MAX_MESSAGE_LEN};

# fn handle(raw_bytes: Vec<u8>) -> Result<(), Box<dyn std::error::Error>> {
let mut buf = Bytes::from(raw_bytes);
let msg = decode_message(&mut buf, MAX_MESSAGE_LEN)?;

match msg {
    Message::Update(update) => {
        let parsed = update.parse(
            true,   // 4-octet AS numbers negotiated
            false,  // Add-Path not negotiated for body NLRI
            &[],    // Add-Path families for MP NLRI (empty = none)
        )?;
        for entry in &parsed.announced {
            println!("announced: {}", entry.prefix);
        }
        for attr in &parsed.attributes {
            println!("attribute: {:?}", attr);
        }
    }
    Message::Open(open) => {
        println!("OPEN: as={} hold={} caps={}", open.my_as, open.hold_time, open.capabilities.len());
    }
    _ => {}
}
# Ok(()) }

Build and encode an OPEN message:

use std::net::Ipv4Addr;
use rustbgpd_wire::{Afi, Capability, encode_message, Message, OpenMessage, Safi};

let open = OpenMessage {
    version: 4,
    my_as: 65000,
    hold_time: 90,
    bgp_identifier: Ipv4Addr::new(10, 0, 0, 1),
    capabilities: vec![
        Capability::FourOctetAs { asn: 65000 },
        Capability::MultiProtocol { afi: Afi::Ipv4, safi: Safi::Unicast },
        Capability::RouteRefresh,
    ],
};
let bytes = encode_message(&Message::Open(open));

Key types

• Message — top-level enum: Open, Update, Keepalive, Notification, RouteRefresh
• UpdateMessage / ParsedUpdate — raw wire form and parsed routes + attributes
• PathAttribute — 13 typed variants plus Unknown pass-through, including AsPath, NextHop, Communities, MpReachNlri, LargeCommunities, and PmsiTunnel (RFC 6514)
• Prefix — V4(Ipv4Prefix) / V6(Ipv6Prefix) enum
• Capability — OPEN capabilities: multi-protocol, 4-octet AS, Add-Path, graceful restart, etc.
• FlowSpecRule / FlowSpecComponent — FlowSpec NLRI with all 13 match types
• EvpnRoute / EvpnRouteKey — typed EVPN routes (Types 1–5) with full payloads (RFC 7432, RFC 9136)
• PmsiTunnel / PmsiTunnelType / PmsiTunnelIdentifier — PMSI Tunnel attribute (RFC 6514 §5) carried on EVPN Type 3 IMET routes for ingress-replication BUM. Constructor PmsiTunnel::for_evpn_ingress_replication(vni, ip) emits the RFC 8365 §5.1.3 wire shape (raw 24-bit VNI in the label field, originator IP as the tunnel identifier).
• RouteDistinguisher — RFC 4364 §4.2 8-byte RD, used by EVPN and VPNv4/v6. Implements Display + FromStr for the standard asn:val / ipv4:val textual encodings
• DfElectionExtendedCommunity (attribute) — RFC 8584 §2.2 / RFC 9785 §3 DF Election Extended Community: ExtendedCommunity::as_df_election() decodes one, ExtendedCommunity::df_election(algorithm, capabilities, preference) constructs it (EVPN DF election algorithm, capabilities, and the RFC 9785 preference / Don't-Preempt fields)
• Link Bandwidth (draft-ietf-idr-link-bandwidth) — ExtendedCommunity::as_link_bandwidth() decodes the advertising AS and the IEEE-754 bytes/second bandwidth from a non-transitive two-octet-AS-specific community (type 0x40 subtype 0x04); ExtendedCommunity::link_bandwidth(asn, bytes_per_sec) constructs one, for weighting unequal-cost multipath next hops
• UpdateValidationOptions — opt-in relaxations for validate_update_attributes_with_options, e.g. accepting a link-local-primary IPv4 MP_REACH_NLRI next-hop on a scoped unnumbered session (RFC 8950)
• DecodeError / EncodeError — structured error types via thiserror
• Well-known community constants — u32 values for matching and setting standard communities: COMMUNITY_NO_EXPORT / COMMUNITY_NO_ADVERTISE / COMMUNITY_NO_EXPORT_SUBCONFED (RFC 1997), COMMUNITY_BLACKHOLE (RFC 7999), COMMUNITY_GRACEFUL_SHUTDOWN (RFC 8326), COMMUNITY_LLGR_STALE / COMMUNITY_NO_LLGR (RFC 9494)

Fuzz tested

Three fuzz targets exercise the decode paths continuously in CI:

• decode_message — full BGP message framing
• decode_update — UPDATE parsing with Add-Path and MP-BGP variants
• decode_flowspec — FlowSpec NLRI component decoding

License

MIT OR Apache-2.0