add test cases

Signed-off-by: Lukas Raffelt <lukas.raffelt@mercedes-benz.com>

reset integration test to default parameters

Signed-off-by: Lukas Raffelt <lukas.raffelt@mercedes-benz.com>

client_linux.go

@@ -552,21 +552,22 @@ func decodeSSID(b []byte) string {
 	return buf.String()
 }
 
-// func decodeBSSLoad(b []byte) (stationCount uint16, channelUtilization uint8, availableAdmissionCapacity uint1) {
+// decodeBSSLoad Decodes the BSSLoad IE. Supports Version 1 and Version 2
+// values according to https://raw.githubusercontent.com/wireshark/wireshark/master/epan/dissectors/packet-ieee80211.c
 func decodeBSSLoad(b []byte) (*BSSLoad, error) {
-	// values from https://raw.githubusercontent.com/wireshark/wireshark/master/epan/dissectors/packet-ieee80211.c
-	// TODO(lukas-mbag) add error handling
 	var load BSSLoad
 	if len(b) == 5 {
+		// Wiresahrk calls this "802.11e CCA Version"
 		load.Version = 2
-		load.StationCount = binary.LittleEndian.Uint16(b[0:])
-		load.ChannelUtilization = b[2]
-		load.AvailableAdmissionCapacity = binary.LittleEndian.Uint16(b[3:])
+		load.StationCount = binary.LittleEndian.Uint16(b[0:2])               // first 2 bytes
+		load.ChannelUtilization = b[2]                                       // next 1 byte
+		load.AvailableAdmissionCapacity = binary.LittleEndian.Uint16(b[3:5]) // last 2 bytes
 	} else if len(b) == 4 {
+		// Wiresahrk calls this "Cisco QBSS Version 1 - non CCA"
 		load.Version = 1
-		load.StationCount = binary.LittleEndian.Uint16(b[0:])
-		load.ChannelUtilization = b[2]
-		load.AvailableAdmissionCapacity = uint16(b[3])
+		load.StationCount = binary.LittleEndian.Uint16(b[0:2]) // first 2 bytes
+		load.ChannelUtilization = b[2]                         // next 1 byte
+		load.AvailableAdmissionCapacity = uint16(b[3])         // next 1 byte
 	} else {
 		err := errInvalidBSSLoad
 		return nil, err

client_linux_test.go

@@ -567,7 +567,8 @@ func Test_decodeBSSLoad(t *testing.T) {
 		wantChannelUtilization         uint8
 		wantAvailableAdmissionCapacity uint16
 	}{
-		{name: "Parse BSS Load", args: args{b: []byte{3, 0, 8, 0x8D, 0x5B}}, wantVersion: 2, wantStationCount: 3, wantChannelUtilization: 8, wantAvailableAdmissionCapacity: 23437},
+		{name: "Parse BSS Load Normal", args: args{b: []byte{3, 0, 8, 0x8D, 0x5B}}, wantVersion: 2, wantStationCount: 3, wantChannelUtilization: 8, wantAvailableAdmissionCapacity: 23437},
+		{name: "Parse BSS Load Version 1", args: args{b: []byte{9, 0, 8, 0x8D}}, wantVersion: 1, wantStationCount: 9, wantChannelUtilization: 8, wantAvailableAdmissionCapacity: 141},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -591,3 +592,11 @@ func Test_decodeBSSLoad(t *testing.T) {
 		})
 	}
 }
+
+func Test_decodeBSSLoadError(t *testing.T) {
+	t.Parallel()
+	_, err := decodeBSSLoad([]byte{3, 0, 8})
+	if err == nil {
+		t.Error("want error on bogus IE with wrong length")
+	}
+}

wifi.go

@@ -186,12 +186,17 @@ type BSSLoad struct {
 
 // String returns the string representation of a BSSLoad.
 func (l BSSLoad) String() string {
-	return fmt.Sprintf("BSSLoad Version: %d    stationCount: %d    channelUtilization: %d/255     availableAdmissionCapacity: %d [*32us/s]\n",
-		l.Version,
-		l.StationCount,
-		l.ChannelUtilization,
-		l.AvailableAdmissionCapacity,
-	)
+	if l.Version == 1 {
+		return fmt.Sprintf("BSSLoad Version: %d    stationCount: %d    channelUtilization: %d/255     availableAdmissionCapacity: %d\n",
+			l.Version, l.StationCount, l.ChannelUtilization, l.AvailableAdmissionCapacity,
+		)
+	} else if l.Version == 2 {
+		return fmt.Sprintf("BSSLoad Version: %d    stationCount: %d    channelUtilization: %d/255     availableAdmissionCapacity: %d [*32us/s]\n",
+			l.Version, l.StationCount, l.ChannelUtilization, l.AvailableAdmissionCapacity,
+		)
+	} else {
+		return fmt.Sprintf("invalid BSSLoad Version: %d", l.Version)
+	}
 }
 
 // A BSS is an 802.11 basic service set.  It contains information about a wireless