+/* Given a datpath, packet, and flow metadata ('backer', 'packet', and 'key'
+ * respectively), populates 'flow' with the result of odp_flow_key_to_flow().
+ * Optionally, if nonnull, populates 'fitnessp' with the fitness of 'flow' as
+ * returned by odp_flow_key_to_flow(). Also, optionally populates 'ofproto'
+ * with the ofproto_dpif, and 'odp_in_port' with the datapath in_port, that
+ * 'packet' ingressed.
+ *
+ * If 'ofproto' is nonnull, requires 'flow''s in_port to exist. Otherwise sets
+ * 'flow''s in_port to OFPP_NONE.
+ *
+ * This function does post-processing on data returned from
+ * odp_flow_key_to_flow() to help make VLAN splinters transparent to the rest
+ * of the upcall processing logic. In particular, if the extracted in_port is
+ * a VLAN splinter port, it replaces flow->in_port by the "real" port, sets
+ * flow->vlan_tci correctly for the VLAN of the VLAN splinter port, and pushes
+ * a VLAN header onto 'packet' (if it is nonnull).
+ *
+ * Similarly, this function also includes some logic to help with tunnels. It
+ * may modify 'flow' as necessary to make the tunneling implementation
+ * transparent to the upcall processing logic.
+ *
+ * Returns 0 if successful, ENODEV if the parsed flow has no associated ofport,
+ * or some other positive errno if there are other problems. */
+int
+xlate_receive(const struct dpif_backer *backer, struct ofpbuf *packet,
+ const struct nlattr *key, size_t key_len,
+ struct flow *flow, enum odp_key_fitness *fitnessp,
+ struct ofproto_dpif **ofproto, odp_port_t *odp_in_port)
+{
+ enum odp_key_fitness fitness;
+ const struct xport *xport;
+ int error = ENODEV;
+
+ ovs_rwlock_rdlock(&xlate_rwlock);
+ fitness = odp_flow_key_to_flow(key, key_len, flow);
+ if (fitness == ODP_FIT_ERROR) {
+ error = EINVAL;
+ goto exit;
+ }
+
+ if (odp_in_port) {
+ *odp_in_port = flow->in_port.odp_port;
+ }
+
+ xport = xport_lookup(tnl_port_should_receive(flow)
+ ? tnl_port_receive(flow)
+ : odp_port_to_ofport(backer, flow->in_port.odp_port));
+
+ flow->in_port.ofp_port = xport ? xport->ofp_port : OFPP_NONE;
+ if (!xport) {
+ goto exit;
+ }
+
+ if (vsp_adjust_flow(xport->xbridge->ofproto, flow)) {
+ if (packet) {
+ /* Make the packet resemble the flow, so that it gets sent to
+ * an OpenFlow controller properly, so that it looks correct
+ * for sFlow, and so that flow_extract() will get the correct
+ * vlan_tci if it is called on 'packet'.
+ *
+ * The allocated space inside 'packet' probably also contains
+ * 'key', that is, both 'packet' and 'key' are probably part of
+ * a struct dpif_upcall (see the large comment on that
+ * structure definition), so pushing data on 'packet' is in
+ * general not a good idea since it could overwrite 'key' or
+ * free it as a side effect. However, it's OK in this special
+ * case because we know that 'packet' is inside a Netlink
+ * attribute: pushing 4 bytes will just overwrite the 4-byte
+ * "struct nlattr", which is fine since we don't need that
+ * header anymore. */
+ eth_push_vlan(packet, flow->vlan_tci);
+ }
+ /* We can't reproduce 'key' from 'flow'. */
+ fitness = fitness == ODP_FIT_PERFECT ? ODP_FIT_TOO_MUCH : fitness;
+ }
+ error = 0;
+
+ if (ofproto) {
+ *ofproto = xport->xbridge->ofproto;
+ }
+
+exit:
+ if (fitnessp) {
+ *fitnessp = fitness;
+ }
+ ovs_rwlock_unlock(&xlate_rwlock);
+ return error;
+}
+