fdump

Overview ¶

Package fdump is a framework to create an application to capture network packet and decode the packet. It use a tui to show the packets.

Here's the way to create your packet capture application: 1. make a function to decode the binary packet and return an Record. 2. make a function to show a brief message of the record. 3. make a function to show a detail message of the record. 4. (optional)Make some hook to modify the replay workflow.

Example:

func decode(net, transport gopacket.Flow, buf []byte) (bodies []interface{}, n int, err error) {
	if len(buf) < 4 {
		err = fdump.ErrPkgNoEnough
		return
	}
	pkgLen := binary.BigEndian.Uint32(buf)
	if uint32(len(buf)) < pkgLen {
		err = fdump.ErrPkgNoEnough
		return
	}
	str := string(buf[4:pkgLen])
	bodies = append(bodies, str)
	n = pkgLen
	return
}

func brief(record *fdump.Record) []string {
	if record == nil || len(record.Bodies) == 0 {
		return nil
	}
	str, ok := record.Bodies[0].(string)
	if !ok {
		return nil
	}
	return []string{str[:10]}
}

func detail(record *fdump.Record) string {
	str, ok := record.Bodies[0].(string)
	if !ok {
		return ""
	}
	return str
}

func postSend(conn net.Conn, record *fdump.Record) error {
	lenBuf := make([]byte, 4)
	lenLen := 0
	for lenLen < 4 {
		err := conn.SetReadDeadline(time.Now().Add(1*time.Second))
		if err != nil {
			return err
		}
		n, err := conn.Read(headBuf[lenLen:])
		if err != nil {
			return err
		}
		lenLen += n
	}

	bodyLen := binary.BigEndian.Uint32(lenBuf) - 4
	body := make([]byte, bodyLen)
	curLen := 0
	for curLen < int(bodyLen) {
		err := conn.SetReadDeadline(time.Now().Add(t*time.Second))
		if err != nil {
			return err
		}
		n, err := conn.Read(body[curlen:])
		if err != nil {
			return err
		}
		curlen += n
	}
	return nil
}

func main() {
	logging.SetLevel(logging.INFO, "")
	fdump.Init()
	replayHook := &fdump.ReplayHook{
		PostSend: postSend,
	}
	briefAttributes := []*fdump.BriefColumnAttribute{&fdump.BriefColumnAttribute{
			Title: "Head10",
			MaxWidth: 10,
		},
	}

	a := fdump.NewApp(decode, brief, detail, replayHook, briefAttributes)
	a.Run()
}

If you want to add your owner command flag, please use fdump.AppFlagSet.

The framework use github.com/op/go-logging to write log. You can get the some log : `logging.MustGetLogger(fdump.LoggerName)`.

Modify the logger level: `logging.SetLevel(logging.INFO, "")`