Add unit tests for Ethernet and VLAN manipulation functions

Author: vista-

dhcpv4/nclient4/ethernet_test.go

@@ -0,0 +1,176 @@
+//go:build go1.12
+// +build go1.12
+
+package nclient4
+
+import (
+	"bytes"
+	"net"
+	"testing"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/u-root/uio/uio"
+)
+
+var (
+	testMac = net.HardwareAddr{0x01, 0x02, 0x03, 0x04, 0x05, 0x06}
+	// Test payload 123456789abcdefghijklmnopqrstvwxyz
+	// This length is required to avoid zero-padding the Ethernet frame from the right side
+	testPayload = gopacket.Payload{0x54, 0x65, 0x73, 0x74, 0x20, 0x70, 0x61, 0x79, 0x6c, 0x6f, 0x61, 0x64, 0x20, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x76, 0x77, 0x78, 0x79, 0x7a}
+
+	ethHdrIPv4 = &layers.Ethernet{
+		DstMAC:       BroadcastMac,
+		SrcMAC:       testMac,
+		EthernetType: layers.EthernetTypeIPv4,
+	}
+	ethHdrVLAN = &layers.Ethernet{
+		DstMAC:       BroadcastMac,
+		SrcMAC:       testMac,
+		EthernetType: layers.EthernetTypeDot1Q,
+	}
+	ethHdrARP = &layers.Ethernet{
+		DstMAC:       BroadcastMac,
+		SrcMAC:       testMac,
+		EthernetType: layers.EthernetTypeARP,
+	}
+	vlanTagOuter = &layers.Dot1Q{
+		Priority:       0,
+		DropEligible:   false,
+		VLANIdentifier: 100,
+		Type:           layers.EthernetTypeDot1Q,
+	}
+	vlanTagInner = &layers.Dot1Q{
+		Priority:       0,
+		DropEligible:   false,
+		VLANIdentifier: 200,
+		Type:           layers.EthernetTypeIPv4,
+	}
+	ipv4Hdr = &layers.IPv4{
+		SrcIP: net.IP{1, 2, 3, 4},
+		DstIP: net.IP{5, 6, 7, 8},
+	}
+	opts = gopacket.SerializeOptions{}
+)
+
+func TestProcessVLANStack(t *testing.T) {
+	for _, tt := range []struct {
+		name        string
+		inputBytes  []byte
+		vlanConfig  []uint16
+		wantSuccess bool
+	}{
+		{"no VLANs + no VLANs configured", []byte{0x08, 0x00}, []uint16{}, true},
+		{"no VLANs + VLAN configured", []byte{0x08, 0x00}, []uint16{100}, false},
+		{"valid VLAN stack (single)", []byte{0x81, 0x00, 0x01, 0x00, 0x08, 0x00}, []uint16{0x100}, true},
+		{"invalid VLAN stack (single)", []byte{0x81, 0x00, 0x01, 0xFF, 0x08, 0x00}, []uint16{0x100}, false},
+		{"valid VLAN stack (double)", []byte{0x81, 0x00, 0x01, 0x00, 0x81, 0x00, 0x02, 0x00, 0x08, 0x00}, []uint16{0x100, 0x200}, true},
+		{"invalid VLAN stack (double)", []byte{0x81, 0x00, 0x01, 0x00, 0x81, 0x00, 0x02, 0xFF, 0x08, 0x00}, []uint16{0x100, 0x200}, false},
+		{"invalid VLAN stack (too short)", []byte{0x81, 0x00, 0x01, 0x00, 0x08, 0x00}, []uint16{0x100, 0x200}, false},
+		{"invalid VLAN stack (too long)", []byte{0x81, 0x00, 0x01, 0x00, 0x81, 0x00, 0x02, 0x00, 0x08, 0x00}, []uint16{0x100}, false},
+		{"invalid packet (ARP)", []byte{0x08, 0x06}, []uint16{}, false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			testBuf := uio.NewBigEndianBuffer(tt.inputBytes)
+			testSuccess := processVLANStack(testBuf, tt.vlanConfig)
+
+			if testSuccess != tt.wantSuccess {
+				t.Errorf("got %v, want %v", testSuccess, tt.wantSuccess)
+			}
+		})
+	}
+}
+
+func TestCreateVLANTag(t *testing.T) {
+	// Gopacket builds VLAN tags the other way around: first VLAN ID/TCI, then TPID, due to their different layered approach
+	// Since a VLAN tag is only 4 bytes, and the value is well-known, it makes sense to just construct the packet by hand.
+	want := []byte{0x81, 0x00, 0x01, 0x23}
+
+	test := createVLANTag(0x0123)
+
+	if !bytes.Equal(test, want) {
+		t.Errorf("got %v, want %v", test, want)
+	}
+}
+
+func TestGetEthernetPayload(t *testing.T) {
+	for _, tt := range []struct {
+		name       string
+		testLayers []gopacket.SerializableLayer
+		wantLayers []gopacket.SerializableLayer
+		vlanConfig []uint16
+	}{
+		{"no VLAN", []gopacket.SerializableLayer{ethHdrIPv4, ipv4Hdr, testPayload}, []gopacket.SerializableLayer{ipv4Hdr, testPayload}, []uint16{}},
+		{"single VLAN", []gopacket.SerializableLayer{ethHdrVLAN, vlanTagInner, ipv4Hdr, testPayload}, []gopacket.SerializableLayer{ipv4Hdr, testPayload}, []uint16{200}},
+		{"QinQ", []gopacket.SerializableLayer{ethHdrVLAN, vlanTagOuter, vlanTagInner, ipv4Hdr, testPayload}, []gopacket.SerializableLayer{ipv4Hdr, testPayload}, []uint16{100, 200}},
+		{"invalid VLAN", []gopacket.SerializableLayer{ethHdrVLAN, vlanTagInner, ipv4Hdr, testPayload}, nil, []uint16{300}},
+		{"invalid packet (ARP)", []gopacket.SerializableLayer{ethHdrARP}, nil, []uint16{}},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			testBuf := gopacket.NewSerializeBuffer()
+			err := gopacket.SerializeLayers(testBuf, opts, tt.testLayers...)
+			if err != nil {
+				t.Errorf("error serializing in gopacket (not our bug!)")
+			}
+
+			var want []byte
+			if tt.wantLayers == nil {
+				want = nil
+			} else {
+				wantBuf := gopacket.NewSerializeBuffer()
+				err := gopacket.SerializeLayers(wantBuf, opts, tt.wantLayers...)
+				if err != nil {
+					t.Errorf("error serializing in gopacket (not our bug!)")
+				}
+				want = wantBuf.Bytes()
+			}
+
+			testBytes := testBuf.Bytes()
+			test := getEthernetPayload(testBytes, tt.vlanConfig)
+
+			if !bytes.Equal(test, want) {
+				t.Errorf("got %v, want %v", test, want)
+			}
+		})
+	}
+}
+
+func TestAddEthernetHdrTwo(t *testing.T) {
+	for _, tt := range []struct {
+		name       string
+		testLayers []gopacket.SerializableLayer
+		wantLayers []gopacket.SerializableLayer
+		vlanConfig []uint16
+	}{
+		{"no VLAN", []gopacket.SerializableLayer{ipv4Hdr, testPayload}, []gopacket.SerializableLayer{ethHdrIPv4, ipv4Hdr, testPayload}, []uint16{}},
+		{"single VLAN", []gopacket.SerializableLayer{ipv4Hdr, testPayload}, []gopacket.SerializableLayer{ethHdrVLAN, vlanTagInner, ipv4Hdr, testPayload}, []uint16{200}},
+		{"QinQ", []gopacket.SerializableLayer{ipv4Hdr, testPayload}, []gopacket.SerializableLayer{ethHdrVLAN, vlanTagOuter, vlanTagInner, ipv4Hdr, testPayload}, []uint16{100, 200}},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			testBuf := gopacket.NewSerializeBuffer()
+			err := gopacket.SerializeLayers(testBuf, opts, tt.testLayers...)
+			if err != nil {
+				t.Errorf("error serializing in gopacket (not our bug!)")
+			}
+
+			var want []byte
+			if tt.wantLayers == nil {
+				want = nil
+			} else {
+				wantBuf := gopacket.NewSerializeBuffer()
+				err := gopacket.SerializeLayers(wantBuf, opts, tt.wantLayers...)
+				if err != nil {
+					t.Errorf("error serializing in gopacket (not our bug!)")
+				}
+				want = wantBuf.Bytes()
+			}
+
+			testBytes := testBuf.Bytes()
+			test := addEthernetHdr(testBytes, BroadcastMac, testMac, etherIPv4Proto, tt.vlanConfig)
+
+			if !bytes.Equal(test, want) {
+				t.Errorf("got %v, want %v", test, want)
+			}
+		})
+	}
+}