feat(decoders): add support for decoding HwTrap and LinuxDropReason Host sFlow extensions

decoders/sflow/datastructure.go

@@ -91,6 +91,17 @@ type ExtendedFunction struct {
 	Symbol string `json:"symbol"`
 }
 
+// Host sFlow extension: Devlink Trap name
+type ExtendedHwTrap struct {
+	Group string `json:"group"`
+	Trap  string `json:"trap"`
+}
+
+// Host sFlow extension: Linux drop_monitor reason
+type ExtendedLinuxDropReason struct {
+	Reason string `json:"reason"`
+}
+
 // IfCounters stores interface counter statistics.
 type IfCounters struct {
 	IfIndex            uint32 `json:"if-index"`

decoders/sflow/sflow.go

@@ -37,9 +37,11 @@ const (
 	FLOW_TYPE_EXT_VLAN_TUNNEL  = 1012
 
 	// According to https://sflow.org/sflow_drops.txt
-	FLOW_TYPE_EGRESS_QUEUE = 1036
-	FLOW_TYPE_EXT_ACL      = 1037
-	FLOW_TYPE_EXT_FUNCTION = 1038
+	FLOW_TYPE_EGRESS_QUEUE          = 1036
+	FLOW_TYPE_EXT_ACL               = 1037
+	FLOW_TYPE_EXT_FUNCTION          = 1038
+	FLOW_TYPE_EXT_HW_TRAP           = 1041
+	FLOW_TYPE_EXT_LINUX_DROP_REASON = 1042
 )
 
 // Opaque counter_data types according to https://sflow.org/SFLOW-STRUCTS5.txt
@@ -351,6 +353,18 @@ func DecodeFlowRecord(header *RecordHeader, payload *bytes.Buffer) (FlowRecord,
 			return flowRecord, &RecordError{header.DataFormat, err}
 		}
 		flowRecord.Data = function
+	case FLOW_TYPE_EXT_HW_TRAP:
+		var hwTrap ExtendedHwTrap
+		if err := utils.BinaryDecoder(payload, &hwTrap.Group, &hwTrap.Trap); err != nil {
+			return flowRecord, &RecordError{header.DataFormat, err}
+		}
+		flowRecord.Data = hwTrap
+	case FLOW_TYPE_EXT_LINUX_DROP_REASON:
+		var linuxDrop ExtendedLinuxDropReason
+		if err := utils.BinaryDecoder(payload, &linuxDrop.Reason); err != nil {
+			return flowRecord, &RecordError{header.DataFormat, err}
+		}
+		flowRecord.Data = linuxDrop
 	default:
 		var rawRecord RawRecord
 		rawRecord.Data = payload.Bytes()

decoders/utils/utils.go

@@ -55,11 +55,12 @@ func BinaryRead(payload BytesBuffer, order binary.ByteOrder, data any) error {
 			*data = order.Uint64(bs)
 		case *string:
 			strlen := int(order.Uint32(bs))
-			buf := payload.Next(strlen)
+			paddedlen := (strlen + 3) &^ 3 // Pad to 4-byte boundary
+			buf := payload.Next(paddedlen)
 			if len(buf) < strlen {
 				return io.ErrUnexpectedEOF
 			}
-			*data = string(buf)
+			*data = string(buf[:strlen])
 		case []bool:
 			for i, x := range bs { // Easier to loop over the input for 8-bit values.
 				data[i] = x != 0