golang implements ptp protocol

PTP (Precision Time Protocol) is a time synchronization protocol that can achieve sub-microsecond level time synchronization in distributed systems. In fields such as industrial automation and network communications, time synchronization is very important. The implementation of the PTP protocol has always been a hot topic, and Golang is an efficient programming language. Its natural concurrency characteristics and good memory management mechanism make it one of the preferred languages ​​for implementing the PTP protocol.

1. PTP protocol overview

The PTP protocol is formulated by IEEE Standard 1588 and is mainly used for network communication to achieve time synchronization between network nodes in a distributed system. The PTP protocol accurately synchronizes the precision time information between the reference clock and the slave clock through the network, so that the reference clock and the slave clock are basically consistent.

The PTP protocol mainly consists of two roles, Master clock and Slave clock. The Master clock broadcasts Sync messages through the network. The Slave clock accepts the Sync messages of the Master clock, calculates the delay with the Master clock based on the Delay Request message, and performs clock and time calibration through the Follow Up message. .

2. Golang implements PTP protocol

The advantage of Golang is that it is very easy to write correct concurrent code. At the same time, the memory management mechanism in Golang also helps developers solve memory leaks, etc. question. These features are very beneficial for implementing the PTP protocol.

2.1 PTP protocol structure

The PTP protocol mainly consists of two parts: messages and packets, so we can represent them by defining structures in Golang.

For messages in the PTP protocol, we can use the following definition method:

type Header struct{

   TransportSpecific uint8
   Version           uint8
   MessageLength     uint16
   DomainNumber      uint8
   Flags             PTPFlags
   CorrectionField   int64
   SourcePortIdentity PortIdentity
   SequenceID        uint16
   ControlField      uint8
   LogMessageInterval uint8

}

For reports in the PTP protocol Text, we can use the following definition:

type SyncMessage struct{

   Header Header
   OriginTimestamp uint64

}

This is the definition of a Sync message, which contains the Header structure and OriginTimestamp field. Other messages can be defined similarly.

2.2 PTP protocol analysis and generation

In the process of implementing the PTP protocol, we need to parse and generate network data. Therefore, we need to use the binary package in Golang to parse and generate network byte order.

Taking the Sync message as an example, we can define a ParseSyncMessage function to parse the network byte order of the Sync message.

func ParseSyncMessage(data []byte) (*SyncMessage, error) {

    msg := new(SyncMessage)
    err := binary.Read(bytes.NewReader(data), binary.BigEndian, &msg.Header)
    if err != nil {
            return nil, err
    }
    err = binary.Read(bytes.NewReader(data[40:48]), binary.BigEndian, &msg.OriginTimestamp)
    if err != nil {
            return nil, err
    }
    return msg, nil

}

This function reads the Header and OriginTimestamp fields from the network data. And returns a structure of type SyncMessage. The parsing functions of other messages can be implemented similarly.

For generating PTP protocol messages, we can define a function GenerateSyncMessage to generate Sync messages. This function sets each field of the Sync message to the corresponding value, and finally generates a Sync message in network byte order.

func GenerateSyncMessage() ([]byte, error) {

    msg := new(SyncMessage)
    msg.Header.TransportSpecific = 0x80
    msg.Header.Version = 2
    msg.Header.MessageLength = 44
    msg.Header.DomainNumber = 0
    msg.Header.ControlField = 0x00
    msg.Header.SequenceID = 1
    msg.Header.SourcePortIdentity = PortIdentity{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0xff, 0xfe}
    msg.Header.Flags = PTPFlag(0x00)
    msg.Header.CorrectionField = 0
    msg.OriginTimestamp = uint64(time.Now().UnixNano())
    b := new(bytes.Buffer)
    err := binary.Write(b, binary.BigEndian, &msg)
    if err != nil {
            return nil, err
    }
    return b.Bytes(), nil

}

2.3 Network communication of PTP protocol

The PTP protocol mainly broadcasts through the network Sync message for clock synchronization. Therefore, we need to use the net package in Golang to implement network communication.

The following is the implementation method of broadcasting Sync messages to the network:

func BroadCastSyncMessage() error {

    conn, err := net.ListenPacket("udp4", ":319")
    if err != nil {
            return err
    }
    defer conn.Close()

    for {
            b, err := GenerateSyncMessage()
            if err != nil {
                    return err
            }
            _, err = conn.WriteTo(b, &net.UDPAddr{IP: net.IPv4(224, 0, 1, 129), Port: 319})
            if err != nil {
                    return err
            }
            time.Sleep(time.Second)
    }
    return nil

}

This function always broadcasts to the network Sync messages are broadcast once every second. The sending methods of other messages can also be implemented similarly.

3. Summary

This article introduces how to use Golang to implement the PTP protocol. Through structure definition, network data analysis and generation, and network communication, we can easily implement the PTP protocol and achieve time synchronization between network nodes. Golang's natural concurrency characteristics and good memory management mechanism make the implementation of the PTP protocol easier.

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