PPPoE usses a midchain adjacency stack on an interface-tx DPO

1) introduce an interface-tx DPO. This is a simple wrapper around a sw_if_index. enhance DPO stacking functions to allow per-instance next-nodes and hence allow children to stack onto the interface per-instance tx node and not on 'interface-output'.
2) update PPPoE code to use ta midchain stack on a interface-tx DPO of the encap-interface. This remove the need for pppoe_encap node (which is replaced by the adj-midchain-tx) and interface-output node is no longer used (see above). Since PPPoE encap node is no longer needed, the PPPoE seesion does not need to be retrieved in the data-path, hence the cahce misses are removed.

Change-Id: Id8b40f53daa14889a9c51d802e14fed7fba4399a
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/src/vnet/dpo/interface_rx_dpo.h b/src/vnet/dpo/interface_rx_dpo.h
new file mode 100644
index 00000000000..edecce08675
--- /dev/null
+++ b/src/vnet/dpo/interface_rx_dpo.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __INTERFACE_RX_DPO_H__
+#define __INTERFACE_RX_DPO_H__
+
+#include <vnet/dpo/dpo.h>
+
+/**
+ * @brief
+ * The data-path object representing a change of receive interface.
+ * If a packet encounters an object of this type in the data-path, it's
+ * RX interface is changed.
+ */
+typedef struct interface_rx_dpo_t_
+{
+    /**
+     * The Software interface index that the packets will be given
+     * as the ingress/rx interface
+     */
+    u32 ido_sw_if_index;
+
+    /**
+     * next VLIB node. A '<proto>-input' node.
+     */
+    u32 ido_next_node;
+
+    /**
+     * DPO protocol that the packets will have as they 'ingress'
+     * on this interface
+     */
+    dpo_proto_t ido_proto;
+
+    /**
+     * number of locks.
+     */
+    u16 ido_locks;
+} interface_rx_dpo_t;
+
+extern void interface_rx_dpo_add_or_lock (dpo_proto_t proto,
+                                          u32 sw_if_index,
+                                          dpo_id_t *dpo);
+
+extern void interface_rx_dpo_module_init(void);
+
+/**
+ * @brief pool of all interface DPOs
+ */
+interface_rx_dpo_t *interface_rx_dpo_pool;
+
+static inline interface_rx_dpo_t *
+interface_rx_dpo_get (index_t index)
+{
+    return (pool_elt_at_index(interface_rx_dpo_pool, index));
+}
+
+#endif