static int vector_legacy_rx()

in drivers/vector_kern.c [840:905]

• 57 lines of code
• 9 McCabe index (conditional complexity)

static int vector_legacy_rx(struct vector_private *vp)
{
	int pkt_len;
	struct user_msghdr hdr;
	struct iovec iov[2 + MAX_IOV_SIZE]; /* header + data use case only */
	int iovpos = 0;
	struct sk_buff *skb;
	int header_check;

	hdr.msg_name = NULL;
	hdr.msg_namelen = 0;
	hdr.msg_iov = (struct iovec *) &iov;
	hdr.msg_control = NULL;
	hdr.msg_controllen = 0;
	hdr.msg_flags = 0;

	if (vp->header_size > 0) {
		iov[0].iov_base = vp->header_rxbuffer;
		iov[0].iov_len = vp->header_size;
	}

	skb = prep_skb(vp, &hdr);

	if (skb == NULL) {
		/* Read a packet into drop_buffer and don't do
		 * anything with it.
		 */
		iov[iovpos].iov_base = drop_buffer;
		iov[iovpos].iov_len = DROP_BUFFER_SIZE;
		hdr.msg_iovlen = 1;
		vp->dev->stats.rx_dropped++;
	}

	pkt_len = uml_vector_recvmsg(vp->fds->rx_fd, &hdr, 0);
	if (pkt_len < 0) {
		vp->in_error = true;
		return pkt_len;
	}

	if (skb != NULL) {
		if (pkt_len > vp->header_size) {
			if (vp->header_size > 0) {
				header_check = vp->verify_header(
					vp->header_rxbuffer, skb, vp);
				if (header_check < 0) {
					dev_kfree_skb_irq(skb);
					vp->dev->stats.rx_dropped++;
					vp->estats.rx_encaps_errors++;
					return 0;
				}
				if (header_check > 0) {
					vp->estats.rx_csum_offload_good++;
					skb->ip_summed = CHECKSUM_UNNECESSARY;
				}
			}
			pskb_trim(skb, pkt_len - vp->rx_header_size);
			skb->protocol = eth_type_trans(skb, skb->dev);
			vp->dev->stats.rx_bytes += skb->len;
			vp->dev->stats.rx_packets++;
			netif_rx(skb);
		} else {
			dev_kfree_skb_irq(skb);
		}
	}
	return pkt_len;
}