Add flock.fritzlab.net/ip-algo as a node-wide default via NodeConfig
metadata.annotations. Pod-level annotation still wins. Empty, missing,
or invalid input at either level falls through to the next; invalid
values warn-log via the agent's slog. Both unset → fully random IID
(unchanged baseline).
ParseAnnotations no longer touches ip-algo; ResolveIPAlgo handles the
full precedence chain, called from PodHandler.Add with the cached
NodeConfig's annotations and the agent logger.
Tests: 9 new TestResolveIPAlgo_* cases covering pod-wins, all
fall-through paths, both-absent, nil node map, whitespace, and
duplicate-as-invalid. Fuzz target rebuilt without ip-algo input space
(now exercised by ResolveIPAlgo unit tests).
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>
Donavan Fritz