[PATCH] app/test-pmd: fix L4 checksum with padding data

[Stephen Hemminger]

On Fri, 17 Nov 2023 13:11:50 +0100
Morten Brørup <mb at smartsharesystems.com> wrote:

> > rte_ipv4_udptcp_cksum_mbuf() and rte_ipv6_udptcp_cksum_mbuf() are
> > inline
> > functions, unfortunately we can't version them.
> > 
> > But those functions already gets IP header as parameter, can't we use
> > IP
> > header to get the payload size? If so this can be fixed without
> > updating
> > API.  
> 
> If rte_ipv4_udptcp_cksum_mbuf() - or any other function in the DPDK Network Headers library - includes Ethernet padding (which may be non-zero) when calculating the TCP/UDP checksum of an IPv4 packet, it is a bug, and must be fixed there.
> 
> Our test cases should use random padding to catch bugs like this.
> 
> And I just realized that Ethernet padding may be added to any IP packet, so don't assume that this bug only applies to small packets.

Agree. And test code needs lots more header checks it is way too trusting that mbuf is valid.