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, 92 insertions, 0 deletions

diff --git a/src/vnet/dpo/interface_tx_dpo.c b/src/vnet/dpo/interface_tx_dpo.c
new file mode 100644
index 00000000000..f7c8bfda85b
--- /dev/null
+++ b/src/vnet/dpo/interface_tx_dpo.c
@@ -0,0 +1,92 @@
+/*
+ * 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.
+ */
+
+#include <vnet/dpo/interface_tx_dpo.h>
+#include <vnet/adj/rewrite.h>
+
+/*
+ * We do not lock nor unlock these DPOs since there is nothing to lock
+ * all we do is construct DPO object wrappers around a sw_if_index
+ */
+static void
+interface_tx_dpo_lock (dpo_id_t *dpo)
+{
+}
+
+static void
+interface_tx_dpo_unlock (dpo_id_t *dpo)
+{
+}
+
+/*
+ * interface_tx_dpo_add_or_lock
+ *
+ * construct DPO object wrappers around a sw_if_index
+ */
+void
+interface_tx_dpo_add_or_lock (dpo_proto_t proto,
+                              u32 sw_if_index,
+                              dpo_id_t *dpo)
+{
+    dpo_set(dpo, DPO_INTERFACE_TX, proto, sw_if_index);
+}
+
+u8*
+format_interface_tx_dpo (u8* s, va_list *ap)
+{
+    index_t index = va_arg(*ap, index_t);
+    CLIB_UNUSED(u32 indent) = va_arg(*ap, u32);
+    vnet_main_t * vnm = vnet_get_main();
+
+    return (format(s, "%U-dpo:",
+                   format_vnet_sw_interface_name,
+                   vnm,
+                   vnet_get_sw_interface(vnm, index)));
+}
+
+static void
+interface_tx_dpo_mem_show (void)
+{
+}
+
+u32*
+interface_tx_dpo_get_next_node (const dpo_id_t *dpo)
+{
+    u32 *node_indices = NULL;
+
+    /*
+     * return the interface's TX node for the wrapped sw_if_index
+     */
+    vec_add1(node_indices,
+             vnet_tx_node_index_for_sw_interface(vnet_get_main(),
+                                                 dpo->dpoi_index));
+
+    return (node_indices);
+}
+
+const static dpo_vft_t interface_tx_dpo_vft = {
+    .dv_lock = interface_tx_dpo_lock,
+    .dv_unlock = interface_tx_dpo_unlock,
+    .dv_format = format_interface_tx_dpo,
+    .dv_mem_show = interface_tx_dpo_mem_show,
+    .dv_get_next_node = interface_tx_dpo_get_next_node,
+};
+
+void
+interface_tx_dpo_module_init (void)
+{
+    dpo_register(DPO_INTERFACE_TX, &interface_tx_dpo_vft, NULL);
+}
+