implement rotating nonce list

net/lux_noncelist.go

@@ -0,0 +1,46 @@
+package net
+
+import "math/rand/v2"
+
+const LUX_NONCE_MAX = 128
+
+// Anti replay measure.
+type LuxNonceList struct {
+	nonces []uint64
+}
+
+func GenerateLuxNonce() uint64 {
+	return rand.Uint64()
+}
+
+func NewLuxNonceList() LuxNonceList {
+	return LuxNonceList{
+		nonces: make([]uint64, 0),
+	}
+}
+
+func (list *LuxNonceList) RotateOrFail(newNonce uint64) bool {
+	for _, nonce := range list.nonces {
+		if nonce == newNonce {
+			return false
+		}
+	}
+
+	if len(list.nonces) == LUX_NONCE_MAX {
+		// rotate
+		for i := LUX_NONCE_MAX - 1; i > 0; i-- {
+			list.nonces[i] = list.nonces[i-1]
+		}
+
+		list.nonces[0] = newNonce
+	} else {
+		// append to head
+		list.nonces = append([]uint64{newNonce}, list.nonces...)
+	}
+
+	return true
+}
+
+func (list *LuxNonceList) Get(idx int) uint64 {
+	return list.nonces[idx]
+}

tests/lux_noncelist_test.go

@@ -0,0 +1,26 @@
+package tests
+
+import (
+	"lux/net"
+	"testing"
+)
+
+func TestNonces(t *testing.T) {
+	list := net.NewLuxNonceList()
+	for i := 0; i < 129; i++ {
+		if !list.RotateOrFail(net.GenerateLuxNonce()) {
+			t.Fatal("duplicate 64bit nonce per 129 items")
+		}
+	}
+
+	// sanity checks
+	if list.Get(0) == list.Get(1) {
+		t.Fatal("list.Get(0) == list.Get(1)")
+	}
+	if list.Get(0) == list.Get(127) {
+		t.Fatal("list.Get(0) == list.Get(127)")
+	}
+	if list.Get(126) == list.Get(127) {
+		t.Fatal("list.Get(26) == list.Get(127)")
+	}
+}