From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Olivier MATZ <olivier.matz@6wind.com>,
dev@dpdk.org, yuanhan.liu@linux.intel.com
Cc: konstantin.ananyev@intel.com, sugesh.chandran@intel.com,
bruce.richardson@intel.com, jianfeng.tan@intel.com,
helin.zhang@intel.com, adrien.mazarguil@6wind.com,
stephen@networkplumber.org, dprovan@bivio.net,
xiao.w.wang@intel.com
Subject: Re: [dpdk-dev] [PATCH v2 09/12] virtio: add Rx checksum offload support
Date: Tue, 11 Oct 2016 16:36:10 +0200 [thread overview]
Message-ID: <65d18f11-9a51-a9d8-a649-6285fcdd0b2b@redhat.com> (raw)
In-Reply-To: <57FCF75E.3090205@6wind.com>
On 10/11/2016 04:29 PM, Olivier MATZ wrote:
>
>
> On 10/11/2016 04:04 PM, Maxime Coquelin wrote:
>>> +/* Optionally fill offload information in structure */
>>> +static int
>>> +virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
>>> +{
>>> + struct rte_net_hdr_lens hdr_lens;
>>> + uint32_t hdrlen, ptype;
>>> + int l4_supported = 0;
>>> +
>>> + /* nothing to do */
>>> + if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
>>> + return 0;
>>> +
>>> + m->ol_flags |= PKT_RX_IP_CKSUM_UNKNOWN;
>>> +
>>> + ptype = rte_net_get_ptype(m, &hdr_lens, RTE_PTYPE_ALL_MASK);
>>> + m->packet_type = ptype;
>>> + if ((ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_TCP ||
>>> + (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_UDP ||
>>> + (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_SCTP)
>>> + l4_supported = 1;
>>> +
>>> + if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
>>> + hdrlen = hdr_lens.l2_len + hdr_lens.l3_len + hdr_lens.l4_len;
>>> + if (hdr->csum_start <= hdrlen && l4_supported) {
>>> + m->ol_flags |= PKT_RX_L4_CKSUM_NONE;
>>> + } else {
>>> + /* Unknown proto or tunnel, do sw cksum. We can assume
>>> + * the cksum field is in the first segment since the
>>> + * buffers we provided to the host are large enough.
>>> + * In case of SCTP, this will be wrong since it's a CRC
>>> + * but there's nothing we can do.
>>> + */
>>> + uint16_t csum, off;
>>> +
>>> + csum = rte_raw_cksum_mbuf(m, hdr->csum_start,
>>> + rte_pktmbuf_pkt_len(m) - hdr->csum_start);
>>> + if (csum != 0xffff)
>> Why don't we do the 1-complement if 0xffff?
>
> This was modified after a comment from Xiao.
>
> In checksum arithmetic (ones' complement), there are 2 equivalent ways
> to say the checksum is 0: 0xffff (0-), and 0x0000 (0+).
> Some protocols like UDP use this to differentiate between 0xffff (packet
> checksum is 0) and 0x0000 (packet checksum is not calculated).
>
> Here, we want to avoid to set a checksum to 0, in case it would mean no
> checksum for UDP packets. Instead, it is set to 0xffff, which is also a
> valid checksum for this packet.
Ha ok, I wasn't aware of this.
Thanks for the explanation!
Maybe not a big deal, but we could add likely around the test?
Maxime
>
> Regards,
> Olivier
next prev parent reply other threads:[~2016-10-11 14:36 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-21 8:08 [dpdk-dev] [PATCH 00/12] net/virtio: add " Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 01/12] virtio: move device initialization in a function Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 02/12] virtio: setup and start cq in configure callback Olivier Matz
2016-07-21 21:15 ` Stephen Hemminger
2016-07-22 7:54 ` Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 03/12] virtio: reinitialize the device " Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 04/12] mbuf: add function to calculate a checksum Olivier Matz
2016-07-21 10:51 ` Ananyev, Konstantin
2016-07-21 16:26 ` Don Provan
2016-07-21 16:46 ` Olivier Matz
2016-07-22 8:24 ` Olivier Matz
2016-08-29 14:52 ` Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 05/12] mbuf: add new Rx checksum mbuf flags Olivier Matz
2016-07-21 21:22 ` Stephen Hemminger
2016-07-22 8:03 ` Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 06/12] app/testpmd: fix checksum stats in csum engine Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 07/12] mbuf: new flag for LRO Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 08/12] app/testpmd: display lro segment size Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 09/12] virtio: add Rx checksum offload support Olivier Matz
2016-07-27 9:52 ` Wang, Xiao W
2016-07-21 8:08 ` [dpdk-dev] [PATCH 10/12] virtio: add Tx " Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 11/12] virtio: add Lro support Olivier Matz
2016-07-21 8:08 ` [dpdk-dev] [PATCH 12/12] virtio: add Tso support Olivier Matz
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 00/12] net/virtio: add offload support Olivier Matz
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 01/12] virtio: move device initialization in a function Olivier Matz
2016-10-11 12:30 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 02/12] virtio: setup and start cq in configure callback Olivier Matz
2016-10-11 12:47 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 03/12] virtio: reinitialize the device " Olivier Matz
2016-10-11 13:13 ` Maxime Coquelin
2016-10-12 14:41 ` Yuanhan Liu
2016-10-12 16:01 ` Olivier MATZ
2016-10-13 7:54 ` Yuanhan Liu
2016-10-13 13:57 ` Olivier MATZ
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 04/12] net: add function to calculate a checksum in a mbuf Olivier Matz
2016-10-11 13:25 ` Maxime Coquelin
2016-10-11 13:33 ` Olivier MATZ
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 05/12] mbuf: add new Rx checksum mbuf flags Olivier Matz
2016-10-11 13:43 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 06/12] app/testpmd: fix checksum stats in csum engine Olivier Matz
2016-10-11 13:46 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 07/12] mbuf: new flag for LRO Olivier Matz
2016-10-11 13:48 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 08/12] app/testpmd: display lro segment size Olivier Matz
2016-10-11 13:49 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 09/12] virtio: add Rx checksum offload support Olivier Matz
2016-10-03 12:51 ` Maxime Coquelin
2016-10-05 11:56 ` Olivier Matz
2016-10-05 13:27 ` Maxime Coquelin
2016-10-05 13:30 ` Olivier Matz
2016-10-12 13:02 ` Yuanhan Liu
2016-10-12 15:55 ` Olivier MATZ
2016-10-11 14:04 ` Maxime Coquelin
2016-10-11 14:29 ` Olivier MATZ
2016-10-11 14:36 ` Maxime Coquelin [this message]
2016-10-11 14:49 ` Olivier MATZ
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 10/12] virtio: add Tx " Olivier Matz
2016-10-07 7:25 ` Maxime Coquelin
2016-10-07 16:36 ` Olivier Matz
2016-10-13 8:38 ` Yuanhan Liu
2016-10-13 13:58 ` Olivier MATZ
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 11/12] virtio: add Lro support Olivier Matz
2016-10-11 14:21 ` Maxime Coquelin
2016-10-03 9:00 ` [dpdk-dev] [PATCH v2 12/12] virtio: add Tso support Olivier Matz
2016-10-13 8:18 ` Yuanhan Liu
2016-10-13 14:02 ` Olivier MATZ
2016-10-13 14:16 ` Yuanhan Liu
2016-10-13 14:52 ` Olivier MATZ
2016-10-13 15:01 ` Yuanhan Liu
2016-10-13 15:15 ` Olivier MATZ
2016-10-13 15:29 ` Yuanhan Liu
2016-10-13 15:45 ` Olivier Matz
2016-10-13 16:01 ` Yuanhan Liu
2016-10-13 15:04 ` Yuanhan Liu
2016-10-13 23:33 ` Stephen Hemminger
2016-10-18 14:07 ` Olivier Matz
2016-10-11 11:35 ` [dpdk-dev] [PATCH v2 00/12] net/virtio: add offload support Yuanhan Liu
2016-10-11 12:14 ` Olivier MATZ
2016-10-11 15:37 ` Yuanhan Liu
2016-10-13 14:15 ` [dpdk-dev] [PATCH v3 " Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 01/12] net/virtio: move device initialization in a function Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 02/12] net/virtio: setup and start cq in configure callback Olivier Matz
2016-11-02 1:38 ` Yao, Lei A
2016-11-08 14:58 ` Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 03/12] net/virtio: reinitialize the device " Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 04/12] net: add function to calculate a checksum in a mbuf Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 05/12] mbuf: add new Rx checksum mbuf flags Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 06/12] app/testpmd: adapt checksum stats in csum engine Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 07/12] mbuf: new flag for LRO Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 08/12] app/testpmd: display lro segment size Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 09/12] net/virtio: add Rx checksum offload support Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 10/12] net/virtio: add Tx " Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 11/12] net/virtio: add Lro support Olivier Matz
2016-10-13 14:16 ` [dpdk-dev] [PATCH v3 12/12] net/virtio: add Tso support Olivier Matz
2016-10-13 16:05 ` Yuanhan Liu
2016-10-13 18:50 ` Thomas Monjalon
2016-10-13 19:58 ` Olivier Matz
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