NodeConfig defaults + code-quality pass + fuzz tests + README

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>
2026-04-25 09:25:45 -05:00
parent 677aec2a42
commit 71e584cf96
17 changed files with 1583 additions and 100 deletions
@@ -0,0 +1,103 @@
+package embed
+
+import (
+	"net"
+	"testing"
+)
+
+// FuzzEmbed verifies that Embed never panics and that any successful return
+// keeps the output address inside the requested network.
+func FuzzEmbed(f *testing.F) {
+	type seed struct {
+		prefix    string
+		fields    string // comma-separated, mapped below to []Field
+		ns, pod   string
+		image     string
+		fallback  string
+		nNibble   byte
+	}
+	for _, s := range []seed{
+		{"2602:817:3000:f001::/64", "namespace,pod,image", "mail", "stalwart-0", "", "ctr", 0xe},
+		{"2001:db8::/64", "namespace", "ns", "p", "", "", 0},
+		{"2001:db8::/96", "pod", "", "podname", "", "ctr", 0xf},
+		{"2001:db8::/48", "namespace,pod", "ns", "p", "", "ctr", 0x1},
+		{"2001:db8::/120", "namespace", "n", "p", "", "ctr", 0x0},   // 8 host nibbles
+		{"2001:db8::/124", "namespace", "n", "p", "", "ctr", 0x0},   // 4 host nibbles
+		{"2001:db8::/127", "namespace", "n", "p", "", "ctr", 0x0},   // not nibble-aligned
+		{"2001:db8::/63", "namespace", "n", "p", "", "ctr", 0x0},    // not nibble-aligned
+		{"2001:db8::/64", "namespace,pod,image", "", "", "sha256:abcdef0123456789aabbccddeeff00112233445566778899aabbccddeeff0011", "", 0xa},
+		{"2001:db8::/64", "namespace,pod,image", "", "", "", "ctr", 0xa},
+		{"2001:db8::/64", "namespace", "🦆", "🐧", "", "", 0},
+		{"2001:db8::/64", "namespace", "ns\x00\x00", "p", "", "", 0},
+	} {
+		f.Add(s.prefix, s.fields, s.ns, s.pod, s.image, s.fallback, s.nNibble)
+	}
+
+	f.Fuzz(func(t *testing.T, prefix, fieldsStr, ns, pod, image, fallback string, nNibble byte) {
+		_, network, err := net.ParseCIDR(prefix)
+		if err != nil {
+			return
+		}
+		fields, ok := decodeFields(fieldsStr)
+		if !ok {
+			return
+		}
+		got, err := Embed(network, fields, Values{
+			Namespace:     ns,
+			Pod:           pod,
+			Image:         image,
+			ImageFallback: fallback,
+		}, nNibble)
+		if err != nil {
+			return
+		}
+		if !network.Contains(got) {
+			t.Fatalf("Embed(%s, %v) = %s, outside network", prefix, fields, got)
+		}
+		// Property: low nibble of last byte equals nNibble & 0x0F.
+		if want := nNibble & 0x0F; got[len(got)-1]&0x0F != want {
+			t.Fatalf("low nibble = %x, want %x", got[len(got)-1]&0x0F, want)
+		}
+	})
+}
+
+func decodeFields(s string) ([]Field, bool) {
+	if s == "" {
+		return nil, false
+	}
+	var out []Field
+	cur := []byte{}
+	flush := func() bool {
+		if len(cur) == 0 {
+			return true
+		}
+		switch string(cur) {
+		case string(FieldNamespace):
+			out = append(out, FieldNamespace)
+		case string(FieldPod):
+			out = append(out, FieldPod)
+		case string(FieldImage):
+			out = append(out, FieldImage)
+		default:
+			return false
+		}
+		cur = cur[:0]
+		return true
+	}
+	for i := 0; i < len(s); i++ {
+		if s[i] == ',' {
+			if !flush() {
+				return nil, false
+			}
+			continue
+		}
+		cur = append(cur, s[i])
+	}
+	if !flush() {
+		return nil, false
+	}
+	if len(out) == 0 {
+		return nil, false
+	}
+	return out, true
+}