[dpdk-stable] [dpdk-dev] [PATCH] app/testpmd: fix l4 sw csum over multi segments

[Stephen Hemminger]

On Fri, 15 Oct 2021 13:13:06 +0800
Xiaoyun Li <xiaoyun.li at intel.com> wrote:

> +		/* When sw csum is needed, multi-segs needs a buf to contain
> +		 * the whole packet for later UDP/TCP csum calculation.
> +		 */
> +		if (m->nb_segs > 1 && !(tx_ol_flags & PKT_TX_TCP_SEG) &&
> +		    !(tx_offloads & UDP_TCP_CSUM)) {
> +			l3_buf = rte_zmalloc("csum l3_buf",
> +					     info.pkt_len - info.l2_len,
> +					     RTE_CACHE_LINE_SIZE);
> +			rte_pktmbuf_read(m, info.l2_len,
> +					 info.pkt_len - info.l2_len, l3_buf);
> +			l3_hdr = l3_buf;
> +		} else
> +			l3_hdr = (char *)eth_hdr + info.l2_len;
>  

Rather than copying whole packet, make the code handle checksum streaming.