On 2026/7/23 6:22, Stephen Hemminger wrote:
On Mon, 6 Jul 2026 21:20:50 +0800
Xingui Yang <[email protected]> wrote:
Allow set txpkts to accept packet lengths as small as one byte,
enabling generation of runt frames and ultra-small packets for
testing NIC padding logic and undersized frame handling.
The txonly engine handles three ranges: normal (>= 42 bytes) with
full Ethernet/IPv4/UDP headers, runt (14-41 bytes) with truncated
headers, and ultra-small (< 14 bytes) filled with a repeating
pattern. Checksum offloads are disabled when headers are incomplete.
Minimum length validation in set_tx_pkt_segments() is relaxed from
42 to 1 byte. Random split and multi-flow still require the full
header stack in the first segment, as enforced by tx_only_begin().
Signed-off-by: Xingui Yang <[email protected]>
Suggested-by: Stephen Hemminger <[email protected]>
---
I would suggest that if NIC ever gets a packet < ethernet header it is
an application bug, and driver should drop it as an transmit error.
Or crash with an assert failed. There is no guarantee that this
will ever work.
Therefore can not see why testpmd needs to do this.
For packets with Ethernet header plus a few more bytes, it makes
sense to allow. There are always control level protocols that are
very short.
Haha, I think you're right. We have an internal test case for
ultra-short packets to verify hardware capabilities, and this test case
has been around for many years. We have maintained this private patch
separately for many years. It's possible that other network cards might
not have such a requirement.
Thanks.
Xingui
