# 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, FlowSpec, Add-Path, Extended Messages, and more.
This crate is the wire-protocol foundation of
[rustbgpd](https://github.com/lance0/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
| 1997 | Standard communities (4-byte) |
| 2545 | IPv6 link-local next-hop in `MP_REACH_NLRI` (32-byte form); second-segment validated as `fe80::/10` on receive (rejects malformed advertisements) |
| 2918 | Route Refresh capability |
| 4271 | BGP-4 core: OPEN, UPDATE, NOTIFICATION, KEEPALIVE |
| 4360 | Extended communities (route target, route origin, 4-byte AS) |
| 4456 | Route reflector: ORIGINATOR_ID, CLUSTER_LIST |
| 4486 | NOTIFICATION subcodes |
| 4724 | Graceful restart capability |
| 4760 | MP-BGP: `MP_REACH_NLRI` / `MP_UNREACH_NLRI` |
| 5492 | BGP capabilities |
| 6793 | 4-octet AS numbers |
| 7313 | Enhanced Route Refresh (BoRR / EoRR markers) |
| 7432 | EVPN: Types 1–4 (EAD, MAC/IP, IMET, Ethernet Segment) |
| 7674 | Clarification of MP_REACH_NLRI next-hop encoding |
| 7911 | Add-Path: path ID in NLRI encode/decode |
| 8092 | Large communities (3× u32) |
| 8203 | Admin shutdown communication |
| 8365 | EVPN over VXLAN encapsulation |
| 8538 | Notification GR (N-bit) |
| 8654 | Extended messages (up to 65535 bytes) |
| 8950 | Extended next hop (IPv4 NLRI over IPv6 NH) |
| 8955/8956 | FlowSpec: 13 component types, numeric/bitmask operators; §6.1-compliant `NEXT_HOP` validation (the irrelevant-next-hop case is accepted, not rejected) |
| 9012 | Tunnel Encapsulation attribute |
| 9135 | EVPN integrated routing for IRB |
| 9136 | EVPN Type 5: IP Prefix advertisement |
| 9494 | Long-lived graceful restart capability |
## Usage
Decode a single BGP message from raw bytes:
```rust
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:
```rust
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`** — 18+ attribute types including `AsPath`, `NextHop`, `Communities`, `MpReachNlri`, `LargeCommunities`
- **`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)
- **`DecodeError`** / **`EncodeError`** — structured error types via `thiserror`
## 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