Re: [dpdk-dev] [PATCH] gro: add UDP GRO and VXLAN UDP GRO support

["Hu, Jiayu" <jiayu.hu@intel.com>]

Hi Yi,

This patch supports UDP and VxLAN/UDP, but both are in one patch.
It's too large, and please split it into small patches.

Thanks,
Jiayu

> -----Original Message-----
> From: yang_y_yi@163.com <yang_y_yi@163.com>
> Sent: Wednesday, July 1, 2020 2:48 PM
> To: dev@dpdk.org
> Cc: Hu, Jiayu <jiayu.hu@intel.com>; thomas@monjalon.net;
> yangyi01@inspur.com; yang_y_yi@163.com
> Subject: [PATCH] gro: add UDP GRO and VXLAN UDP GRO support
> 
> From: Yi Yang <yangyi01@inspur.com>
> 
> UDP GRO and VXLAN UDP GRO can help improve VM-to-VM
> UDP performance when VM is enabled UFO or GSO, GRO
> must be supported if GSO, UFO or VXLAN UFO is enabled
> , otherwise, performance gain will be hurt.
> 
> With this enabled in DPDK, OVS DPDK can leverage it
> to improve VM-to-VM UDP performance, this will make
> sure IP fragments will be reassembled once it is
> received from physical NIC.
> 
> Signed-off-by: Yi Yang <yangyi01@inspur.com>
> ---
>  lib/librte_gro/Makefile         |   2 +
>  lib/librte_gro/gro_udp4.c       | 443 ++++++++++++++++++++++++++++++++
>  lib/librte_gro/gro_udp4.h       | 296 +++++++++++++++++++++
>  lib/librte_gro/gro_vxlan_udp4.c | 556
> ++++++++++++++++++++++++++++++++++++++++
>  lib/librte_gro/gro_vxlan_udp4.h | 152 +++++++++++
>  lib/librte_gro/meson.build      |   2 +-
>  lib/librte_gro/rte_gro.c        | 192 +++++++++++---
>  lib/librte_gro/rte_gro.h        |   8 +-
>  8 files changed, 1617 insertions(+), 34 deletions(-)
>  create mode 100644 lib/librte_gro/gro_udp4.c
>  create mode 100644 lib/librte_gro/gro_udp4.h
>  create mode 100644 lib/librte_gro/gro_vxlan_udp4.c
>  create mode 100644 lib/librte_gro/gro_vxlan_udp4.h
> +
> +
> +/*
> + * update the packet length for the flushed packet.
> + */
> +static inline void
> +update_header(struct gro_udp4_item *item)
> +{
> +	struct rte_ipv4_hdr *ipv4_hdr;
> +	struct rte_mbuf *pkt = item->firstseg;
> +	uint16_t frag_offset;
> +
> +	ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
> +			pkt->l2_len);
> +	ipv4_hdr->total_length = rte_cpu_to_be_16(pkt->pkt_len -
> +			pkt->l2_len);
> +
> +	/* Clear MF bit if it is last fragment */
> +	if (item->is_last_frag) {
> +		frag_offset = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
> +		ipv4_hdr->fragment_offset =
> +			rte_cpu_to_be_16(frag_offset &
> ~RTE_IPV4_HDR_MF_FLAG);
> +	}

Need to clear MF bit for non-last fragments, and we also need to clear offset value.

> +}
> +
> +int32_t
> +gro_udp4_reassemble(struct rte_mbuf *pkt,
> +		struct gro_udp4_tbl *tbl,
> +		uint64_t start_time)
> +{
> +	struct rte_ether_hdr *eth_hdr;
> +	struct rte_ipv4_hdr *ipv4_hdr;
> +	uint16_t udp_dl, ip_dl;
> +	uint16_t ip_id, hdr_len;
> +	uint16_t frag_offset = 0;
> +	uint8_t is_last_frag;
> +
> +	struct udp4_flow_key key;
> +	uint32_t cur_idx, prev_idx, item_idx;
> +	uint32_t i, max_flow_num, remaining_flow_num;
> +	int cmp;
> +	uint8_t find;
> +
> +	/*
> +	 * Don't process the packet whose UDP header length is not equal
> +	 * to 20.
> +	 */
> +	if (unlikely(pkt->l4_len != UDP_HDRLEN))
> +		return -1;

UDP header is fixed 8-byte. No need to check here.

> +
> +	eth_hdr = rte_pktmbuf_mtod(pkt, struct rte_ether_hdr *);
> +	ipv4_hdr = (struct rte_ipv4_hdr *)((char *)eth_hdr + pkt->l2_len);
> +	hdr_len = pkt->l2_len + pkt->l3_len + pkt->l4_len;
> +
> +	/*
> +	 * Don't process non-fragment packet.
> +	 */
> +	if (!is_ipv4_fragment(ipv4_hdr))
> +		return -1;
> +
> +	/*
> +	 * Don't process the packet whose payload length is less than or
> +	 * equal to 0.
> +	 */
> +	udp_dl = pkt->pkt_len - hdr_len;
> +	if (udp_dl <= 0)
> +		return -1;

Udp_dl is unit16_t which will not be negative.

> +
> +	ip_dl = rte_be_to_cpu_16(ipv4_hdr->total_length) - pkt->l3_len;
> +	ip_id = rte_be_to_cpu_16(ipv4_hdr->packet_id);
> +	frag_offset = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
> +	is_last_frag = ((frag_offset & RTE_IPV4_HDR_MF_FLAG) == 0) ? 1 : 0;
> +	frag_offset = (uint16_t)(frag_offset & RTE_IPV4_HDR_OFFSET_MASK)
> << 3;