[PATCH v4 4/4] net/af_packet: add software checksum offload support

[Stephen Hemminger]

On Mon,  2 Feb 2026 00:14:56 -0800
scott.k.mitch1 at gmail.com wrote:

> +	if (copy) {
> +		/*
> +		 * Copy headers to new segment to handle indirect mbufs.
> +		 * This ensures we can safely modify checksums without
> +		 * corrupting shared/read-only data.
> +		 */
> +		struct rte_mbuf *seg = rte_pktmbuf_copy(mbuf, mbuf->pool, 0, hdrlens);
> +		if (!seg)
> +			return NULL;
> +
> +		rte_pktmbuf_adj(mbuf, hdrlens);
> +		rte_pktmbuf_chain(seg, mbuf);
> +		mbuf = seg;
> +	} else if (unlikely(!RTE_MBUF_DIRECT(mbuf) || rte_mbuf_refcnt_read(mbuf) > 1))
> +		return NULL;

Maybe just rte_pkmbuf_read() helper that already handles the case of getting
the header if needed.