wip: migrate to mono-repo. SPN has already been moved to spn/

spn/ships/masking.go

@@ -0,0 +1,63 @@
+package ships
+
+import (
+	"crypto/sha1"
+	"net"
+
+	"github.com/mr-tron/base58"
+	"github.com/tevino/abool"
+)
+
+var (
+	maskingEnabled = abool.New()
+	maskingActive  = abool.New()
+	maskingBytes   []byte
+)
+
+// EnableMasking enables masking with the given salt.
+func EnableMasking(salt []byte) {
+	if maskingEnabled.SetToIf(false, true) {
+		maskingBytes = salt
+		maskingActive.Set()
+	}
+}
+
+// MaskAddress masks the given address if masking is enabled and the ship is
+// not public.
+func (ship *ShipBase) MaskAddress(addr net.Addr) string {
+	// Return in plain if masking is not enabled or if ship is public.
+	if maskingActive.IsNotSet() || ship.Public() {
+		return addr.String()
+	}
+
+	switch typedAddr := addr.(type) {
+	case *net.TCPAddr:
+		return ship.MaskIP(typedAddr.IP)
+	case *net.UDPAddr:
+		return ship.MaskIP(typedAddr.IP)
+	default:
+		return ship.Mask([]byte(addr.String()))
+	}
+}
+
+// MaskIP masks the given IP if masking is enabled and the ship is not public.
+func (ship *ShipBase) MaskIP(ip net.IP) string {
+	// Return in plain if masking is not enabled or if ship is public.
+	if maskingActive.IsNotSet() || ship.Public() {
+		return ip.String()
+	}
+
+	return ship.Mask(ip)
+}
+
+// Mask masks the given value.
+func (ship *ShipBase) Mask(value []byte) string {
+	// Hash the IP with masking bytes.
+	hasher := sha1.New() //nolint:gosec // Not used for cryptography.
+	hasher.Write(maskingBytes)
+	hasher.Write(value)
+	masked := hasher.Sum(nil)
+
+	// Return first 8 characters from the base58-encoded hash.
+	return "masked:" + base58.Encode(masked)[:8]
+}