+/*
+ * Check if the destination MAC of a packet is one local VM,
+ * and get its vlan tag, and offset if it is.
+ */
+static inline int __attribute__((always_inline))
+find_local_dest(struct virtio_net *dev, struct rte_mbuf *m,
+ uint32_t *offset, uint16_t *vlan_tag)
+{
+ struct virtio_net_data_ll *dev_ll = ll_root_used;
+ struct ether_hdr *pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+ while (dev_ll != NULL) {
+ if ((dev_ll->vdev->ready == DEVICE_RX)
+ && ether_addr_cmp(&(pkt_hdr->d_addr),
+ &dev_ll->vdev->mac_address)) {
+ /*
+ * Drop the packet if the TX packet is
+ * destined for the TX device.
+ */
+ if (dev_ll->vdev->dev->device_fh == dev->device_fh) {
+ RTE_LOG(DEBUG, VHOST_DATA,
+ "(%"PRIu64") TX: Source and destination"
+ " MAC addresses are the same. Dropping "
+ "packet.\n",
+ dev_ll->vdev->dev->device_fh);
+ return -1;
+ }
+
+ /*
+ * HW vlan strip will reduce the packet length
+ * by minus length of vlan tag, so need restore
+ * the packet length by plus it.
+ */
+ *offset = VLAN_HLEN;
+ *vlan_tag =
+ (uint16_t)
+ vlan_tags[(uint16_t)dev_ll->vdev->dev->device_fh];
+
+ RTE_LOG(DEBUG, VHOST_DATA,
+ "(%"PRIu64") TX: pkt to local VM device id:"
+ "(%"PRIu64") vlan tag: %d.\n",
+ dev->device_fh, dev_ll->vdev->dev->device_fh,
+ (int)*vlan_tag);
+
+ break;
+ }
+ dev_ll = dev_ll->next;
+ }
+ return 0;
+}
+
+static uint16_t
+get_psd_sum(void *l3_hdr, uint64_t ol_flags)
+{
+ if (ol_flags & PKT_TX_IPV4)
+ return rte_ipv4_phdr_cksum(l3_hdr, ol_flags);
+ else /* assume ethertype == ETHER_TYPE_IPv6 */
+ return rte_ipv6_phdr_cksum(l3_hdr, ol_flags);
+}
+
+static void virtio_tx_offload(struct rte_mbuf *m)
+{
+ void *l3_hdr;
+ struct ipv4_hdr *ipv4_hdr = NULL;
+ struct tcp_hdr *tcp_hdr = NULL;
+ struct ether_hdr *eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+ l3_hdr = (char *)eth_hdr + m->l2_len;
+
+ if (m->ol_flags & PKT_TX_IPV4) {
+ ipv4_hdr = l3_hdr;
+ ipv4_hdr->hdr_checksum = 0;
+ m->ol_flags |= PKT_TX_IP_CKSUM;
+ }
+
+ tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
+ tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
+}
+