Files
ferrix/crates/server/proto/config.proto
T
Rayhaan JaufeerallyandClaude Fable 5.1 1fc44798b7 Install best routes in the Linux kernel over netlink
New crate bgp-fib. It follows the routing table's best routes and keeps
the kernel's routing table the same, and learns the machine's interfaces
and addresses from the kernel, which is what says whether a next hop can
be reached.

- netlink: the rtnetlink messages used (routes, addresses, links, errors),
  as bytes and back. No I/O; property tested and fuzzed.
- interfaces: what is directly reachable, and from which interface.
- plan: what to ask the kernel for, given the best routes and what the
  kernel has. No I/O; tested against a model kernel.
- kernel (Linux only): the sockets and the task. Requests go in batches;
  routes of ours found at startup are kept if still right and removed if
  not; a change of interfaces has every route worked out again; a clean
  stop removes our routes.

Only routes marked proto bgp with the configured table and metric are
ever touched. A best route is installed if its next hop is a neighbor;
next hops further away are not resolved through other routes yet, and
such prefixes are counted and shown instead.

Configured with `kernel { table metric }`; off by default. The daemon
needs CAP_NET_ADMIN and stops if the kernel refuses it. On shutdown it
closes sessions and then removes its routes.

/api/kernel and the status page show installed, unresolved and refused
counts, the last error and the interfaces; five bgp_kernel_* metrics.

Testing: scripts/kernel-tests.sh runs, in network namespaces of their
own and with only the capabilities the daemon needs, the installer
against `ip route`, the daemon with a peer, and two daemons that route
for each other with pings across over IPv4 and IPv6.
scripts/linux-vm.sh runs that, or anything else, in a Lima VM from
macOS. CI runs the kernel tests and fuzzes the netlink decoder.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2026-10-02 15:15:43 +02:00

296 lines
12 KiB
Protocol Buffer

syntax = "proto3";
package bgp.server;
// Top level BGP Server configuration.
message BgpConfig {
// The router ID, written as a dotted-quad IPv4 address (e.g. "192.0.2.1").
// Required even on IPv6-only routers per RFC 4271.
string router_id = 1;
// The local 4-byte AS number (RFC 6793).
uint32 local_asn = 2;
// Endpoints to accept incoming BGP connections on.
// Defaults to 0.0.0.0:179 and [::]:179 when empty.
repeated TcpEndpoint listen_endpoints = 3;
// Peers configured on this server.
repeated Peer peers = 4;
// Routes this router originates and announces to every peer.
repeated OriginatedRoute originate = 5;
// Where to serve the HTTP API, status page and metrics. The port is
// required. Unset disables the HTTP server.
TcpEndpoint http_endpoint = 6;
// Initial delay between attempts to connect to a configured peer, in
// seconds. Doubles after each failure up to two minutes. Defaults to 5.
uint32 connect_retry_seconds = 7;
// Connection collisions (RFC 4271 §6.8) against a session that is already
// Established are, by default, resolved by closing the new connection.
// When true they are resolved like any other collision: the connection
// initiated by the higher BGP Identifier survives, and a second connection
// opened by the same side replaces the first. This lets a peer that
// restarted take over from a session we have not yet noticed is dead,
// instead of being refused until the hold timer expires.
bool collision_detect_established_state = 8;
// Connections are accepted only from the addresses of configured peers;
// from anywhere else they are closed before a byte is read. When true,
// any host that can reach a listening endpoint may open a session, as
// any AS it cares to name, and have its routes taken. That is for
// testing on a closed network and nothing else.
bool accept_unconfigured_peers = 9;
// Route origin validation (RFC 6811) and AS path verification with the
// RPKI. Left out, routes are not validated.
Rpki rpki = 10;
// Put the best route of every prefix in the kernel's routing table, so
// that the machine forwards packets by them. Left out, the daemon only
// speaks BGP and the machine's forwarding is not touched.
Kernel kernel = 11;
}
// Installing routes in the kernel. Linux only; the daemon needs the
// CAP_NET_ADMIN capability.
//
// The best route of a prefix is installed if its next hop is a neighbor:
// an address in the network of one of the machine's interfaces. Routes
// are marked as BGP's ("proto bgp"), and every route with that mark, the
// table and the metric below is taken to be this daemon's: what it finds
// at startup and no longer wants, it removes. When the daemon stops in
// good order it removes its routes.
message Kernel {
// The routing table. Defaults to 254, the main table, which is the one
// packets are forwarded by unless rules say otherwise.
uint32 table = 1;
// The metric of the routes. Defaults to 20. Of several routes for a
// prefix the kernel uses the one with the lowest metric.
uint32 metric = 2;
}
// Where to get the validated ROA payloads that say which AS may originate
// which prefixes. With this set, a route whose origin is not authorised
// for its prefix ("invalid") is refused, from every peer that is not in
// our own AS and does not have accept_rpki_invalid set. Routes that
// nothing is known about are taken as before.
//
// A validator that speaks version 2 of the protocol also gives the ASPAs,
// in which networks say who their providers are. With those, a route
// whose AS path cannot have come about by networks passing routes on as
// they should (a route leak, or a made-up path) is refused, from every
// peer that has a role set and does not have accept_aspa_invalid set.
message Rpki {
// The RPKI-to-Router servers (RFC 8210, draft-ietf-sidrops-8210bis) of
// one or more validators, such as Routinator, rpki-client with StayRTR,
// or FORT, in order of preference. The port is required. One is used at
// a time, over plain TCP: keep it on a network you trust.
repeated TcpEndpoint caches = 1;
// How often to ask the cache for changes unprompted, how long to wait
// before trying again after a failure, and how long the data may be used
// without a cache confirming it, after which nothing is invalid any
// more. Each defaults to what the cache says, or to 3600, 600 and 7200.
uint32 refresh_seconds = 2;
uint32 retry_seconds = 3;
uint32 expire_seconds = 4;
}
// A route originated by this router. It is announced with an AS_PATH of the
// local AS and, on each session, that session's local address as next hop.
message OriginatedRoute {
// The prefix in CIDR notation, e.g. "192.0.2.0/24" or "2001:db8::/32".
string prefix = 1;
// ORIGIN attribute: "IGP" (the default), "EGP" or "INCOMPLETE".
string origin = 2;
// Extra copies of the local AS to prepend to the AS_PATH. At most 16.
uint32 as_path_prepend = 3;
// MULTI_EXIT_DISC. Left out of the announcement when unset.
optional uint32 med = 4;
// Standard communities (RFC 1997): "ASN:VALUE", or a well-known name such
// as "NO_EXPORT".
repeated string communities = 5;
// Large communities (RFC 8092): "GLOBAL:LOCAL1:LOCAL2".
repeated string large_communities = 6;
}
// An IP address and port pair.
message TcpEndpoint {
// IP address (V4 or V6).
string address = 1;
// TCP port. Defaults to 179 for BGP when unset.
uint32 port = 2;
}
// Configuration of a BGP peer.
message Peer {
// Human-readable name for logging and diagnostics.
string name = 1;
// Address and port to connect to for this peer.
TcpEndpoint endpoint = 2;
// The peer's 4-byte AS number (RFC 6793).
uint32 remote_asn = 3;
// Hold time to advertise in the OPEN message, in seconds (RFC 4271 §4.2).
// Must be 0 or >= 3. Defaults to 90 when unset.
uint32 hold_time_seconds = 4;
// Source IP address for connections we open to this peer. It is also the
// next hop of the routes we send it. Required when the peer identifies us
// by address and the host has several, e.g. when both speakers run on the
// same machine. Must be the same address family as the endpoint. Unset
// lets the operating system choose.
string local_address = 5;
// The address families to exchange with this peer. Each is offered to the
// peer in our OPEN, and is in use on the session only if the peer offers
// it too (RFC 4760). Defaults to all of them when empty. A session with
// no family in common is refused.
repeated AddressFamily address_families = 6;
// ADD-PATH (RFC 7911): whether to take several routes for one prefix
// from this peer, to send it several, or both. It is in use, for each
// direction and address family, only if the peer agrees. Defaults to
// off: one route for each prefix, as in plain BGP.
AddPath add_path = 7;
// Which of the peer's routes are taken. Left out, the general checks
// apply and there is no limit and no list.
ImportPolicy import = 8;
// What the peer is to us. Not for a peer in our own AS. With it set:
//
// - Our OPEN says what we are to the peer, and a peer that says it is
// something else than configured here is refused (RFC 9234). One side
// having the other down as a customer and the other as a peer is how
// leaks come about.
// - Routes are marked "only to customer" as they come in from a provider,
// a peer or a route server, and as they go out to a customer, a peer
// or a route server client. A route with that mark that comes back up
// from a customer, or across from a second peer, is a leak and is
// refused. This cannot be turned off.
// - Where rpki is configured, the AS paths of the peer's routes are
// verified against the ASPAs: a route from a customer, a peer or a
// route server must have come up through providers all the way; one
// from a provider may have come up and then down.
//
// Left out, none of this is done for the peer.
Role role = 9;
// Refuse the peer unless its OPEN says what it is. By default a peer
// that says nothing (one that does not implement RFC 9234) is taken at
// this configuration's word for it. Needs role.
bool require_role = 10;
}
// What a peer is to us.
enum Role {
ROLE_UNSPECIFIED = 0;
// We buy transit from the peer.
PROVIDER = 1;
// The peer buys transit from us.
CUSTOMER = 2;
// The peer and we exchange our own and our customers' routes.
PEER = 3;
// The peer is an Internet exchange's route server.
ROUTE_SERVER = 4;
// We are a route server and the peer is one of our clients.
ROUTE_SERVER_CLIENT = 5;
}
// What is taken from a peer. Every route is judged before it goes into
// the routing table. One that is refused is dropped, and so is the route
// it would have replaced.
//
// A route whose AS path holds our own AS number is always refused.
message ImportPolicy {
// The most routes the peer may have at a time. One more ends the session
// with Cease / Maximum Number of Prefixes Reached, and the peer is kept
// down for hold_down_seconds. Set it somewhat above what the peer is
// expected to send. Zero is no limit.
uint32 max_prefixes = 1;
// How long the peer is kept down after going over max_prefixes. Neither
// side's connections are taken meanwhile. Defaults to 600.
uint32 hold_down_seconds = 2;
// By default, prefixes that are not routed on the Internet are refused
// (private, loopback, link-local, documentation, multicast and reserved
// space), and so are routes with a reserved, private or documentation AS
// number anywhere in their path. True takes them.
bool accept_bogons = 3;
// By default a default route (0.0.0.0/0 or ::/0) is refused. True takes
// one, as from an upstream that is asked to send it.
bool accept_default_route = 4;
// The longest prefixes taken. Default to 24 and 48, the longest that are
// routed between networks.
uint32 max_ipv4_prefix_length = 5;
uint32 max_ipv6_prefix_length = 6;
// By default the AS path of a route has to begin with the peer's own AS
// number. True takes any, as is needed for an Internet exchange's route
// server, which does not put its AS on the path.
bool accept_any_first_as = 7;
// The longest AS path taken, counted in AS numbers. Defaults to 64.
uint32 max_as_path_length = 8;
// The prefixes the peer may announce. Empty allows any. This is the
// list generated for a peer from the routing registries (with bgpq4,
// say).
repeated PrefixRange prefixes = 9;
// The AS numbers the peer's routes may originate from: the last AS of
// the path. Empty allows any.
repeated uint32 origin_asns = 10;
// By default, where route origin validation is configured (rpki), a
// route that is invalid is refused. True takes it all the same.
bool accept_rpki_invalid = 11;
// By default, where the validator gives ASPAs and the peer has a role,
// a route whose AS path they find invalid is refused. True takes it all
// the same.
bool accept_aspa_invalid = 12;
}
// A prefix, and optionally the more specific prefixes inside it.
message PrefixRange {
// In CIDR notation, e.g. "193.0.0.0/21".
string prefix = 1;
// The longest prefix inside it that is also allowed. Left out, only the
// prefix itself is.
uint32 max_length = 2;
}
// The directions ADD-PATH can be offered for.
enum AddPath {
ADD_PATH_OFF = 0;
// Accept several routes for a prefix from the peer.
ADD_PATH_RECEIVE = 1;
// Send the peer several routes for a prefix.
ADD_PATH_SEND = 2;
ADD_PATH_BOTH = 3;
}
// An address family routes can be exchanged for.
enum AddressFamily {
ADDRESS_FAMILY_UNSPECIFIED = 0;
IPV4_UNICAST = 1;
IPV6_UNICAST = 2;
}