Change Ethernet FSC to Scapy

Question

I need to send distorted Ethernet frames for testing purposes. I turned off unloading for Rx and Tx checksums:

root@T60 :~# ethtool --show-offload eth0 Features for eth0: rx-checksumming: off tx-checksumming: off tx-checksum-ipv4: off [fixed] tx-checksum-unneeded: off [fixed] tx-checksum-ip-generic: off tx-checksum-ipv6: off [fixed] tx-checksum-fcoe-crc: off [fixed] tx-checksum-sctp: off [fixed] 

However, does this offload only include IP, TCP, and UDP checksums? Is it possible to send frames with incorrect frame sequence checking in the Ethernet footer using Scapy? I highly doubt it, since Ethernet FSC computation is probably implemented in the hardware of the network adapter?

Answer 1

• YES, a network device located outside the network, IP checksum, TCP, UDP and UDP checksum are rarely checked.

• YES, SCAPY can compile a packet even into a bad checksum using a raw socket

• just try la :)