GRE ERSPAN Scapy pcap encapsulator

encapsulate-erspan.py

#! /usr/bin/python
from scapy.layers.inet import *
from scapy.layers.l2 import *
from scapy.all import *


class ERSPAN(Packet):
    name = "ERSPAN"
    fields_desc = [BitField("version", 1, 4),
                   BitField("vlan", 0, 12),
                   BitField("priority", 0, 3),
                   BitField("unknown2", 0, 1),
                   BitField("direction", 0, 1),
                   BitField("truncated", 0, 1),
                   BitField("span_id", 0, 10),
                   XIntField("unknown7", 0x00000000)]


def main():
    pcap_file_path = '/tmp/input.pcap'
    output_file_path = '/tmp/output.pcap'
    
    output_file = PcapWriter(output_file_path, append=False, sync=True)
    packets = rdpcap(pcap_file_path)
    for packet in packets:
        fixed_packet = Ether() / \
                       IP() / \
                       GRE(flags=0x1000, proto=0x88be, seqence_number=1796, seqnum_present=1) / \
                       ERSPAN(version=1, vlan=3900, priority=0, unknown2=0, direction=1, truncated=0, span_id=666, unknown7=0) / \
                       packet

        output_file.write(fixed_packet)


if __name__ == '__main__':
    main()

Hey, can you also help me to generate sample script for ERSPAN Type III