On Mon, Jul 14, 2025 at 04:09:11PM -0400, Dean Marx wrote: > On Mon, Jul 14, 2025 at 9:30 AM Bruce Richardson > <bruce.richard...@intel.com> wrote: > > > > The behaviour of VLAN tag stripping Rx offloads is unclear in DPDK, and > > not very well documented. Even the documentation that does exist appears > > contradictory. > > > > For example, the doxygen docs for the mbuf flag > > RTE_MBUF_F_RX_QINQ_STRIPPED says: > > > > "If RTE_MBUF_F_RX_QINQ_STRIPPED is set and RTE_MBUF_F_RX_VLAN_STRIPPED > > is unset, only the outer VLAN is removed from packet data,..." > > > > but the docs for RTE_MBUF_F_RX_QINQ says: > > > > "If the flag RTE_MBUF_F_RX_QINQ_STRIPPED is also present, both VLANs > > headers have been stripped from mbuf data, ..." > > > > Without a good definition of what the correct behaviour is, it's not > > possible to assess and ensure conformance across drivers. Update the > > documentation for NIC features, ethdev and mbuf library to all report > > the same information: that VLAN strip feature is stripping one flag, and > > QinQ strip feature is removing two. > > I'm working on testing QinQ/VLAN stripping features across PMDs, and > so far I've found that our Intel devices are capable of QinQ > stripping, while our Mellanox/Broadcom devices are not. When QinQ > stripping is enabled on an Intel PMD, the test packet is received with > its outer VLAN layer stripped, but the inner VLAN layer remains > intact. Thus, the doxygen example is more accurate for what is > currently supported. I'm also running some tests on VLAN stripping > behavior, I'll update this thread with the results once these are > finished.
I may follow up with you directly on this testing, because from what I've found so far there are some issues with our current VLAN/QinQ support, which requires multiple fixes - some of which aren't even merged yet and will only be in the next release. For example, for correct reporting of a stripped single VLAN tag, I believe patch [1] is necessary. /Bruce [1] https://patches.dpdk.org/project/dpdk/patch/20250714161050.289375-1-bruce.richard...@intel.com/
