quoted

	if (((pkt_flags & RRS_IS_IPV4) && ((pkt_flags & RRS_IS_TCP) ||

(pkt_flags & RRS_IS_UDP))) {

quoted

		if (pkt_flags & RRS_IS_802_3)
			head_len += 8;
		iph = (struct iphdr *) (packet + head_len);
		if ((iph->frag_off != 0 || (pkt_flags & RRS_IS_IP_FRAG))

&& !(pkt_flags & RRS_IS_IP_DF))

quoted

			goto hw_xsum;
	}
	if (!(err_flags & (RRS_ERR_IP_CSUM | RRS_ERR_L4_CSUM))) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
		return;
	}

Btw the captured corrupted packets are ordinary non-fragmented TCP IPv4
packets. But perhaps these flags are dual-use?

Not dual-use.  You could check  flags for corrupted packets and compare it with good packet.
Your corrupted packet is just TCP checksum error ?

Thanks
Xiong