Without a filter, crt001's `network 2602:817:3000:A25::/64` gets
re-advertised to every peer on that subnet. bird installs the BGP /64
with metric 32, beating the kernel-connected route at 256, and all
inter-host VLAN-25 traffic hairpins through the gateway — losing PMTU
9000 and ~30x throughput. Broke Plex 2026-05-04: NFS to nas002 capped
at 7 MB/s, jumbo blackholed.
Add LocalSubnetV6/V4 (CIDR) to NodeBGP. Agent populates by masking the
peer's address to /64 (v6) or /24 (v4) — same fritzlab convention
already in localAddrSameSubnet. Render emits `import where net !=
<subnet>;` per BGP channel when set, falls back to `import all;`
otherwise so existing tests stay green.
Defence in depth: with the matching outbound route-map on crt001
(ROUTE_MAP_CLUSTER_OUT_V{4,6}) the agent now refuses the leak on its
own if the router filter ever drifts.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
NodeConfig.Spec.Defaults adds per-node IPv6/IPv4 family defaults that pod
annotations can override; built-in baseline (v6=true, v4=false) still
applies when the field is omitted.
bird.Render now validates every operator-supplied value (peer addresses,
CIDRs, anycast IPs, source addresses) before templating — fuzz found a
peer address containing `}` produced unbalanced braces in bird.conf.
Failing input preserved as a regression seed.
Fuzz targets added for ParseAnnotations, ParseCNIArgs, HostIfaceName,
canonical, IPAM allocate sequences, embed.Embed, and bird.Render.
Hardened canonical/ipToU32 against nil and non-IPv4 inputs.
README rewritten for outside readers — quickstart, NodeConfig + annotation
reference with worked examples, anycast use cases, comparison vs Calico
and Cilium, requirements, limitations.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
Two coupled changes that fix the anycast advertisement path:
1. Add anycast /128 + /32 prefixes as `route … blackhole` lines in the
protocol static stanzas. BIRD's master tables pick them up at
preference 200 — higher than kernel-learned routes — so they're the
ones the BGP export filter sees.
2. The kernel protocol's export filter now rejects RTS_STATIC. Without
this, BIRD would push its blackhole back into the kernel, clobbering
the agent-installed `<anycast> via <pod-eth0> dev flock<8hex>` route
that's actually responsible for forwarding to the pod.
Result: BIRD has the route to advertise via BGP; the kernel has the
right route to forward; nothing fights over the kernel table.
Replaces the abandoned `gateway recursive` attempt — that's a BIRD 1.x
keyword, not BIRD 2.15.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
Default is `gateway direct` — BIRD silently rejects kernel routes whose
via address isn't on a directly-connected network interface. Our anycast
host routes use a pod /128 (or /32) as via, which is itself a kernel
route on a flock veth, not a connected network. With `gateway
recursive`, BIRD does a recursive lookup and accepts the kernel route.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
Cisco IOS rejects IPv6 BGP advertisements whose next-hop is link-local-
only. BIRD2 was synthesising a link-local next-hop for kernel-learned
routes whose dev had no via gateway (our anycast /128s). Symptom: v4
anycast worked (Cisco doesn't have the same constraint for /32s), v6
anycast didn't make it past crt001.
- pkg/routing/bird/config.go: NodeBGP.LocalV6/LocalV4. Template now
emits `local <addr> as <asn>` and `next hop self;` in the BGP
channel for both families, mirroring Calico's `source address` +
`next hop self` pattern.
- pkg/agent/bird.go: localAddrSameSubnet picks an interface address
on the peer's /64 or /24 to use as source.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
BIRD2's protocol kernel does not import kernel routes by default; the
import filter on the channel is just for what BIRD has already learned.
Added `learn;` so the kernel-installed blackholes (from the agent's
SummaryRoutes) are picked up.
Also added explicit `protocol static static6/static4` with one
`route <cidr> blackhole;` per NodeConfig CIDR. This is belt-and-
suspenders: even if `learn` doesn't capture the kernel blackhole, BIRD
has the route directly and exports it via the BGP filter.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
Donavan Fritz