+/* Optionally fill offload information in structure */
+static int
+virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
+{
+ struct rte_net_hdr_lens hdr_lens;
+ uint32_t hdrlen, ptype;
+ int l4_supported = 0;
+
+ /* nothing to do */
+ if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
+ return 0;
+
+ m->ol_flags |= PKT_RX_IP_CKSUM_UNKNOWN;
+
+ ptype = rte_net_get_ptype(m, &hdr_lens, RTE_PTYPE_ALL_MASK);
+ m->packet_type = ptype;
+ if ((ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_TCP ||
+ (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_UDP ||
+ (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_SCTP)
+ l4_supported = 1;
+
+ if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+ hdrlen = hdr_lens.l2_len + hdr_lens.l3_len + hdr_lens.l4_len;
+ if (hdr->csum_start <= hdrlen && l4_supported) {
+ m->ol_flags |= PKT_RX_L4_CKSUM_NONE;
+ } else {
+ /* Unknown proto or tunnel, do sw cksum. We can assume
+ * the cksum field is in the first segment since the
+ * buffers we provided to the host are large enough.
+ * In case of SCTP, this will be wrong since it's a CRC
+ * but there's nothing we can do.
+ */
+ uint16_t csum, off;
+
+ rte_raw_cksum_mbuf(m, hdr->csum_start,
+ rte_pktmbuf_pkt_len(m) - hdr->csum_start,
+ &csum);
+ if (likely(csum != 0xffff))
+ csum = ~csum;
+ off = hdr->csum_offset + hdr->csum_start;
+ if (rte_pktmbuf_data_len(m) >= off + 1)
+ *rte_pktmbuf_mtod_offset(m, uint16_t *,
+ off) = csum;
+ }
+ } else if (hdr->flags & VIRTIO_NET_HDR_F_DATA_VALID && l4_supported) {
+ m->ol_flags |= PKT_RX_L4_CKSUM_GOOD;
+ }
+
+ return 0;
+}
+
+static inline int
+rx_offload_enabled(struct virtio_hw *hw)
+{
+ return vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_CSUM);
+}
+