将数据包保存到 CSV 文件时发生错误：len

Question

from scapy.all import *
import csv
import socket

def capture_and_save_packets(filter, count, filename):
    try:
        # Start the capture
        packets = sniff(filter=filter, count=count)
    except Exception as e:
        print(f"An error occurred while capturing packets: {e}")
        return None

    try:
        # Open a CSV file to store the packets
        with open(filename, 'w', newline='') as file:
            writer = csv.writer(file)

            # Write the header row
            writer.writerow(["Source", "Destination", "Protocol", "Service", "Duration",
                             "Src_to_Dst_Bytes", "Dst_to_Src_Bytes", "Src_to_Dst_TTL", "Dst_to_Src_TTL",
                             "Src_Retransmitted", "Dst_Retransmitted", "Src_Dropped", "Dst_Dropped"])

            # Write the packets to the CSV file
            for packet in packets:
                service = None
                src_to_dst_bytes = 0
                dst_to_src_bytes = 0
                src_to_dst_ttl = 0
                dst_to_src_ttl = 0
                src_retransmitted = 0
                dst_retransmitted = 0
                src_dropped = 0
                dst_dropped = 0

                if IP in packet:
                    src = packet[IP].src
                    dst = packet[IP].dst
                    proto = packet[IP].proto
                    ttl = packet[IP].ttl
                    duration = packet.time

                    if TCP in packet:
                        service = packet[TCP].dport
                        src_to_dst_bytes = packet[TCP].payload.len
                        dst_to_src_bytes = (packet[TCP].ack - packet[TCP].seq) #- packet[TCP].payload.len
                        if "E" in packet[TCP].flags:
                            src_retransmitted = 1
                        if "R" in packet[TCP].flags:
                            dst_retransmitted = 1
                        if "D" in packet[TCP].flags:
                            src_dropped = 1
                        if "F" in packet[TCP].flags:
                            dst_dropped = 1

                    elif UDP in packet:
                        service = packet[UDP].dport
                        src_to_dst_bytes = packet[UDP].len
                        dst_to_src_bytes = len(packet) - len(packet[UDP])
                        if packet[UDP].chksum == None:
                            src_retransmitted = 1
                            dst_retransmitted = 1
                            src_dropped = 1
                            dst_dropped = 1

                    writer.writerow([src, dst, proto, service, duration,
                                      src_to_dst_bytes, dst_to_src_bytes, src_to_dst_ttl, dst_to_src_ttl,
                                      src_retransmitted, dst_retransmitted, src_dropped, dst_dropped])

    except Exception as e:
        print(f"An error occurred while saving the packets to a CSV file: {e}")
        return None

    print("Packets captured and saved to CSV file successfully.")
    return packets

#Define the filter for the packets you want to capture

filter = "host 192.168.8.102"

#Call the capture_and_save_packets function
packets = capture_and_save_packets(filter, 10 ,"packets.csv")

#print packets to the console
if packets:
    for packet in packets:
        print(packet)

我想捕获数据并将其保存在 csv 文件中，但此错误不断出现