[Bug] "IPv6 header version should be 6 but instead is" error reported for valid IPv6 packets

[isambartm]

Replaying valid IPv6 traffic over Ethernet, I get the following error message for most packets (when first 4 bits of Ethernet Destination MAC not set to "6"):

• "IPv6 header version should be 6 but instead is"

Looking at where this error message is generated (flows.c, lines 242-248), it seems the IPv6 version may be checked using the wrong packet offset. This currently uses "packet[0]", but I think this may need to be "packet[l2len]" instead.

To Reproduce
Steps to reproduce the behavior:

1. Replay IPv6 traffic over Ethernet (first 4 bits of Ethernet Destination MAC should not be set to to "6")

Expected behavior
Traffic should be replayed without error.

System (please complete the following information):

• OS: Red Hat Enterprise Linux
• OS version: 9.4
• Tcpreplay Version: 4.5.1

[fklassen]

Works for me. Please provide a packet capture and command-line syntax.

[isambartm]

Here is an example trace that shows this issue:
https://wiki.wireshark.org/uploads/__moin_import__/attachments/SampleCaptures/v6-http.cap

I just replayed it using:
tcpreplay -i <interface_name> v6-http.cap

[hugo0819]

Hello, I also encountered the same error, I want to know which old versions can be used normally?

[isambartm]

I believe version 4.4.4 won't show this error message.