Add Chain API for managing nftables chains, including Add, Create, Delete, Clear, and Rename operations.

chain/policy.go

@@ -0,0 +1,21 @@
+package chain
+
+import "fmt"
+
+type Policy int8
+
+const (
+	PolicyAccept Policy = iota + 1
+	PolicyDrop
+)
+
+func (p Policy) String() string {
+	switch p {
+	case PolicyAccept:
+		return "accept"
+	case PolicyDrop:
+		return "drop"
+	default:
+		return fmt.Sprintf("unknown policy %d", p)
+	}
+}