new: new can module for CAN-bus

modules/can/can_recon.go

@@ -0,0 +1,131 @@
+package can
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/bettercap/bettercap/network"
+	"github.com/bettercap/bettercap/session"
+	"github.com/evilsocket/islazy/str"
+	"go.einride.tech/can"
+	"go.einride.tech/can/pkg/socketcan"
+)
+
+type Message struct {
+	Frame   can.Frame
+	Name    string
+	Source  *network.CANDevice
+	Signals map[string]string
+}
+
+func (mod *CANModule) Configure() error {
+	var err error
+
+	if mod.Running() {
+		return session.ErrAlreadyStarted(mod.Name())
+	} else if err, mod.deviceName = mod.StringParam("can.device"); err != nil {
+		return err
+	} else if err, mod.transport = mod.StringParam("can.transport"); err != nil {
+		return err
+	} else if mod.transport != "can" && mod.transport != "udp" {
+		return errors.New("invalid transport")
+	} else if err, mod.dbcPath = mod.StringParam("can.dbc_path"); err != nil {
+		return err
+	}
+
+	if mod.dbcPath != "" {
+		input, err := os.ReadFile(mod.dbcPath)
+		if err != nil {
+			return fmt.Errorf("can't read %s: %v", mod.dbcPath, err)
+		}
+
+		mod.Info("compiling %s ...", mod.dbcPath)
+
+		result, err := dbcCompile(mod.dbcPath, input)
+		if err != nil {
+			return fmt.Errorf("can't compile %s: %v", mod.dbcPath, err)
+		}
+
+		for _, warning := range result.Warnings {
+			mod.Warning("%v", warning)
+		}
+
+		mod.dbc = result.Database
+	} else {
+		mod.Warning("no can.dbc_path specified, messages won't be parsed")
+	}
+
+	if mod.conn, err = socketcan.DialContext(context.Background(), mod.transport, mod.deviceName); err != nil {
+		return err
+	}
+
+	mod.recv = socketcan.NewReceiver(mod.conn)
+
+	return nil
+}
+
+func (mod *CANModule) Start() error {
+	if err := mod.Configure(); err != nil {
+		return err
+	}
+
+	return mod.SetRunning(true, func() {
+		mod.Info("started on %s ...", mod.deviceName)
+
+		for mod.recv.Receive() {
+			frame := mod.recv.Frame()
+			msg := Message{
+				Frame: frame,
+			}
+
+			if mod.dbc != nil {
+				if message, found := mod.dbc.Message(frame.ID); found {
+					msg.Name = message.Name
+
+					sourceName := message.SenderNode
+					sourceDesc := ""
+					if sender, found := mod.dbc.Node(message.SenderNode); found {
+						sourceName = sender.Name
+						sourceDesc = sender.Description
+					}
+
+					_, msg.Source = mod.Session.CAN.AddIfNew(sourceName, sourceDesc, frame.Data[:])
+
+					msg.Signals = make(map[string]string)
+
+					for _, signal := range message.Signals {
+						var value string
+
+						if signal.Length <= 32 && signal.IsFloat {
+							value = fmt.Sprintf("%f", signal.UnmarshalFloat(frame.Data))
+						} else if signal.Length == 1 {
+							value = fmt.Sprintf("%v", signal.UnmarshalBool(frame.Data))
+						} else if signal.IsSigned {
+							value = fmt.Sprintf("%d", signal.UnmarshalSigned(frame.Data))
+						} else {
+							value = fmt.Sprintf("%d", signal.UnmarshalUnsigned(frame.Data))
+						}
+
+						msg.Signals[signal.Name] = str.Trim(fmt.Sprintf("%s %s", value, signal.Unit))
+					}
+				}
+			}
+
+			mod.Session.Events.Add("can.message", msg)
+		}
+	})
+}
+
+func (mod *CANModule) Stop() error {
+	if mod.conn != nil {
+		mod.recv.Close()
+		mod.conn.Close()
+		mod.conn = nil
+		mod.recv = nil
+		mod.dbc = nil
+		mod.dbcPath = ""
+	}
+	return nil
+}