+/**
+ * Add an implicit flow rule on the remote device to make sure traffic gets to
+ * the tap netdevice from there.
+ *
+ * @param pmd
+ * Pointer to private structure.
+ * @param[in] idx
+ * The idx in the implicit_rte_flows array specifying which rule to apply.
+ *
+ * @return -1 if the rule couldn't be applied, 0 otherwise.
+ */
+int tap_flow_implicit_create(struct pmd_internals *pmd,
+ enum implicit_rule_index idx)
+{
+ struct rte_flow_item *items = implicit_rte_flows[idx].items;
+ struct rte_flow_attr *attr = &implicit_rte_flows[idx].attr;
+ struct rte_flow_item_eth eth_local = { .type = 0 };
+ uint16_t if_index = pmd->remote_if_index;
+ struct rte_flow *remote_flow = NULL;
+ struct nlmsg *msg = NULL;
+ int err = 0;
+ struct rte_flow_item items_local[2] = {
+ [0] = {
+ .type = items[0].type,
+ .spec = ð_local,
+ .mask = items[0].mask,
+ },
+ [1] = {
+ .type = items[1].type,
+ }
+ };
+
+ remote_flow = rte_malloc(__func__, sizeof(struct rte_flow), 0);
+ if (!remote_flow) {
+ RTE_LOG(ERR, PMD, "Cannot allocate memory for rte_flow");
+ goto fail;
+ }
+ msg = &remote_flow->msg;
+ if (idx == TAP_REMOTE_TX) {
+ if_index = pmd->if_index;
+ } else if (idx == TAP_REMOTE_LOCAL_MAC) {
+ /*
+ * eth addr couldn't be set in implicit_rte_flows[] as it is not
+ * known at compile time.
+ */
+ memcpy(ð_local.dst, &pmd->eth_addr, sizeof(pmd->eth_addr));
+ items = items_local;
+ }
+ tc_init_msg(msg, if_index, RTM_NEWTFILTER,
+ NLM_F_REQUEST | NLM_F_ACK | NLM_F_EXCL | NLM_F_CREATE);
+ msg->t.tcm_info = TC_H_MAKE(0, htons(ETH_P_ALL));
+ tap_flow_set_handle(remote_flow);
+ if (priv_flow_process(pmd, attr, items, NULL, NULL,
+ remote_flow, implicit_rte_flows[idx].mirred)) {
+ RTE_LOG(ERR, PMD, "rte flow rule validation failed\n");
+ goto fail;
+ }
+ err = nl_send(pmd->nlsk_fd, &msg->nh);
+ if (err < 0) {
+ RTE_LOG(ERR, PMD, "Failure sending nl request");
+ goto fail;
+ }
+ err = nl_recv_ack(pmd->nlsk_fd);
+ if (err < 0) {
+ RTE_LOG(ERR, PMD,
+ "Kernel refused TC filter rule creation");
+ goto fail;
+ }
+ LIST_INSERT_HEAD(&pmd->implicit_flows, remote_flow, next);
+ return 0;
+fail:
+ if (remote_flow)
+ rte_free(remote_flow);
+ return -1;
+}
+
+/**
+ * Remove specific implicit flow rule on the remote device.
+ *
+ * @param[in, out] pmd
+ * Pointer to private structure.
+ * @param[in] idx
+ * The idx in the implicit_rte_flows array specifying which rule to remove.
+ *
+ * @return -1 if one of the implicit rules couldn't be created, 0 otherwise.
+ */
+int tap_flow_implicit_destroy(struct pmd_internals *pmd,
+ enum implicit_rule_index idx)
+{
+ struct rte_flow *remote_flow;
+ int cur_prio = -1;
+ int idx_prio = implicit_rte_flows[idx].attr.priority + PRIORITY_OFFSET;
+
+ for (remote_flow = LIST_FIRST(&pmd->implicit_flows);
+ remote_flow;
+ remote_flow = LIST_NEXT(remote_flow, next)) {
+ cur_prio = (remote_flow->msg.t.tcm_info >> 16) & PRIORITY_MASK;
+ if (cur_prio != idx_prio)
+ continue;
+ return tap_flow_destroy_pmd(pmd, remote_flow, NULL);
+ }
+ return 0;
+}
+
+/**
+ * Destroy all implicit flows.
+ *
+ * @see rte_flow_flush()
+ */
+int
+tap_flow_implicit_flush(struct pmd_internals *pmd, struct rte_flow_error *error)
+{
+ struct rte_flow *remote_flow;
+
+ while (!LIST_EMPTY(&pmd->implicit_flows)) {
+ remote_flow = LIST_FIRST(&pmd->implicit_flows);
+ if (tap_flow_destroy_pmd(pmd, remote_flow, error) < 0)
+ return -1;
+ }
+ return 0;
+}
+