From: Olivier Matz <olivier.matz@6wind.com>
To: Lance Richardson <lance.richardson@broadcom.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] question regarding rx checksum offload flags
Date: Thu, 17 Sep 2020 16:05:03 +0200 [thread overview]
Message-ID: <20200917140503.GS21395@platinum> (raw)
In-Reply-To: <CADyeNEDKjT5eKHYWvmag2-cc3xFmnpK8UkouauX57P-+DYA47w@mail.gmail.com>
Hi Lance,
On Mon, Aug 24, 2020 at 04:11:45PM -0400, Lance Richardson wrote:
> I was looking for some clarification regarding how rx checksum
> flags should be set for tunnel packets having both inner and outer
> IP/L4 headers.
>
> Based on comments in rte_mbuf_core.h, it seems to me. that the
> inner (encapsulated) IP header checksum status should determine
> which of these goes into ol_flags:
> PKT_RX_IP_CKSUM_UNKNOWN
> PKT_RX_IP_CKSUM_BAD
> PKT_RX_IP_CKSUM_GOOD
> PKT_RX_IP_CKSUM_NONE
>
> Similarly, the L4 checksum status should determine which of these
> goes into ol_flags:
> PKT_RX_L4_CKSUM_UNKNOWN
> PKT_RX_L4_CKSUM_BAD
> PKT_RX_L4_CKSUM_GOOD
> PKT_RX_L4_CKSUM_NONE
>
> The IP header checksum status for the outer IP header should determine
> whether this flag is set in ol_flags:
> PKT_RX_EIP_CKSUM_BAD
>
> And for UDP-based tunnel encapsulations, the outer L4 checksum status
> should determine which of these goes into ol_flags:
> PKT_RX_OUTER_L4_CKSUM_UNKNOWN
> PKT_RX_OUTER_L4_CKSUM_BAD
> PKT_RX_OUTER_L4_CKSUM_GOOD
> PKT_RX_OUTER_L4_CKSUM_INVALID
>
> Finally, the checksum status of inner headers should have no influence
> on PKT_RX_EIP_CKSUM_BAD or PKT_RX_OUTER_L4_CKSUM_*, and
> likewise the checksum status of outer headers should have no influence
> on PKT_RX_L4_CKSUM_* or PKT_RX_IP_CKSUM_*.
>
> Is this correct? Apologies for such a basic question, but I'm having trouble
> correlating the above with implementations.
>
> Thanks and regards,
> Lance
The PKT_RX_EIP_CKSUM_BAD flag was added by these commits:
https://git.dpdk.org/dpdk/commit/?id=c22265f6fd4cdcac9ee1b4970e4af8459d267516
https://git.dpdk.org/dpdk/commit/?id=d909af8f72ca3f8ab4fe1942abfb4f53e15ff8bc
First, to be honnest, I don't think this API is the right one. From a software
stack point of view, it would have been more logical to have PKT_RX_INNER_*
flags instead of outer.
That said, your understanding looks correct to me. I think this is the
expected behavior when the DEV_RX_OFFLOAD_OUTER* capability is enabled.
If the capability is not set, only the PKT_RX_IP_CKSUM* and
PKT_RX_L4_CKSUM* flags may be set, and they reference the first layer.
Regards,
Olivier
next prev parent reply other threads:[~2020-09-17 14:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-24 20:11 Lance Richardson
2020-08-25 14:39 ` Lance Richardson
2020-08-26 13:39 ` Lance Richardson
2020-09-17 14:05 ` Olivier Matz [this message]
2020-12-14 17:41 ` Lance Richardson
2020-12-15 22:05 ` Lance Richardson
2020-12-18 9:27 ` Olivier Matz
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