How to calculate a packet checksum without sending it?

python scapy
Dima.Go picture Dima.Go · May 10, 2011 · Viewed 15.3k times · Source

I'm using scapy, and I want to create a packet and calculate its' checksum without sending it. Is there a way to do it?

Thanks.

Answer

Almog Cohen picture Almog Cohen · Jul 25, 2012

I've also tried to avoid show2() because it print the packet. I've found in the source a better solution:

del packet.chksum
packet = packet.__class__(bytes(packet))

This code regenerate the packet with the correct checksum without any print and actually is what show2() run in the background before printing.

Related questions

Running Scapy on Windows with Python 2.7

I like to use Scapy with Python v2.7 under Windows 7. How can I install the required module pypcap for Python 2.7? Will it be possible to make Python scripts depending on Scapy into standalone Windows applications using a distribution tool such …

Read More
How can I filter a pcap file by specific protocol using python?

I have some pcap files and I want to filter by protocol, i.e., if I want to filter by HTTP protocol, anything but HTTP packets will remain in the pcap file. There is a tool called openDPI, and it's …

Read More
Scapy packet sniffer triggering an action up on each sniffed packet

I'm using scapy with python to sniff live traffic. capture=sniff(iface="<My Interface>", filter="tcp") But this sniffs each packet and adds it to the list capture which can be processed later. I want to process a …

Read More