Function parseSyncPacket

cmd/ziffy/node/receiver_linux.go:159–181

parseSyncPacket parses SYNC/DELAY_REQ packets and returns the packet, source IP and source port

(packet gopacket.Packet)

// parseSyncPacket parses SYNC/DELAY_REQ packets and returns the packet, source IP and source port
func parseSyncPacket(packet gopacket.Packet) (*ptp.SyncDelayReq, string, string, error) {
	ipHeader, ok := packet.NetworkLayer().(*layers.IPv6)
	if !ok {
		return nil, "", "", fmt.Errorf("unable to parse IPv6 Header")
	}
	udpHeader, ok := packet.TransportLayer().(*layers.UDP)
	if !ok {
		return nil, "", "", fmt.Errorf("unable to parse UDP Header")
	}

	appLayer := packet.ApplicationLayer()
	if appLayer == nil {
		return nil, "", "", fmt.Errorf("unable to parse Application Layer")
	}
	ptpPacket, err := ptp.DecodePacket(appLayer.Payload())
	if err != nil {
		return nil, "", "", fmt.Errorf("unable to decode PTP packet: %w", err)
	}
	if ptpPacket.MessageType() != ptp.MessageSync && ptpPacket.MessageType() != ptp.MessageDelayReq {
		return nil, "", "", fmt.Errorf("not parsing %v: not a SYNC/DELAY_REQ packet", ptpPacket.MessageType().String())
	}
	return ptpPacket.(*ptp.SyncDelayReq), ipHeader.SrcIP.String(), strconv.Itoa(int(udpHeader.SrcPort)), nil
}