[dpapp] Initial dpapp implementation being a vpp plugin (#609)

Following dpapp HLD - #606, this
is the 3th part implementation. It implements the basic logic of inline
flow creation, deletion and ageout.

- Build with command  `make dpapp` 
- Run with command `make run-dpapp`

.github/workflows/dash-bmv2-ci.yml

@@ -62,18 +62,24 @@ jobs:
       run:  make docker-bmv2-bldr
     - name: Generate SAI API
       run:  DOCKER_FLAGS=$docker_fg_flags make sai
+    - name: Pull/Build docker dpapp image
+      run:  make docker-dash-dpapp
+    - name: Build bmv2 dpapp
+      run:  DOCKER_FLAGS=$docker_fg_flags make dpapp
     - name: Check if SAI spec is updated
       run:  DOCKER_FLAGS=$docker_fg_flags make check-sai-spec
     - name: Build libsai c++ tests
       run:  DOCKER_FLAGS=$docker_fg_flags make test
     - name: Prepare network
-      run:  DOCKER_FLAGS=$docker_fg_flags make network
+      run:  DOCKER_FLAGS=$docker_fg_flags make network HAVE_DPAPP=y
     - name: Run P4 software switch (bmv2) with P4Runtime
-      run:  DOCKER_FLAGS=$docker_bg_flags make run-switch
+      run:  DOCKER_FLAGS=$docker_bg_flags make run-switch HAVE_DPAPP=y
     - name: Force bmv2 to load forwarding pipeline config via dummy libsai call
       run:  DOCKER_FLAGS=$docker_fg_flags make init-switch
     - name: Test SAI library over P4RT to switch
       run:  DOCKER_FLAGS=$docker_fg_flags make run-libsai-test
+    - name: Run dpapp
+      run:  DOCKER_FLAGS=$docker_bg_flags make run-dpapp HAVE_DPAPP=y
     - name: Generate saithrift-server
       run:  DOCKER_FLAGS=$docker_fg_flags make saithrift-server
     - name: Generate saithrift-client local docker

.wordlist.txt

@@ -559,6 +559,7 @@ sai
 saic
 SAIC
 saichallenger
+saidashdpapp
 saigen
 sairedis
 SAIRPC

dash-pipeline/dpapp/CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.5)
+
+project(dash-plugin)
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I /SAI/SAI/inc -I /SAI/SAI/experimental")
+
+find_package(VPP)
+
+add_subdirectory(dash)

dash-pipeline/dpapp/Makefile

@@ -0,0 +1,24 @@
+SHELL=/bin/bash
+BUILD_DIR=build
+CMAKE_ARGS=
+
+ifeq ($(V),1)
+CMAKE_ARGS += --verbose
+endif
+
+all: dpapp
+
+.PHONY:configure install clean
+
+configure:
+	@cmake $(CMAKE_ARGS) -G Ninja -S . -B $(BUILD_DIR)
+
+dpapp: configure
+	@cmake --build $(BUILD_DIR) $(CMAKE_ARGS)
+
+clean:
+	@cmake --build $(BUILD_DIR) $(CMAKE_ARGS) -- clean
+
+install:
+	@sudo cmake --build $(BUILD_DIR) $(CMAKE_ARGS) -- install
+

dash-pipeline/dpapp/README.md

@@ -0,0 +1,84 @@
+# DPAPP - Data Plane Application
+## Overview
+DPAPP fulfills [VPP](https://fd.io/) plugin mechanism to implement the slow (exception) path of
+packet processing. It works with [DASH pipeline BMv2](https://github.com/sonic-net/DASH/tree/main/dash-pipeline/bmv2),
+serving fast path, to consist of a complete DASH data plane. Refer to the doc
+[bmv2 data plane app](https://github.com/sonic-net/DASH/blob/main/documentation/dataplane/dash-bmv2-data-plane-app.md)
+for design details.
+
+## Usage
+1. build dpapp
+```
+DASH/dash-pipeline$ make dpapp
+```
+2. Run dpapp
+```
+DASH/dash-pipeline$ make run-dpapp
+```
+
+## Debug
+VPP CLI `vppctl` provides lots of commands for debugging. Use the command `docker exec -it dash-dpapp-${USER} vppctl`
+to launch it.
+
+- Check dpapp interfaces and the counters
+```
+vpp# show interface
+              Name               Idx    State  MTU (L3/IP4/IP6/MPLS)     Counter          Count
+host-veth5                        1      up          9000/0/0/0     rx packets                    39
+                                                                    rx bytes                   10764
+                                                                    tx packets                    39
+                                                                    tx bytes                    7628
+local0                            0     down          0/0/0/0
+
+vpp# show hardware-interfaces
+              Name                Idx   Link  Hardware
+host-veth5                         1     up   host-veth5
+  Link speed: unknown
+  RX Queues:
+    queue thread         mode
+    0     vpp_wk_0 (1)   interrupt
+  TX Queues:
+    TX Hash: [name: hash-eth-l34 priority: 50 description: Hash ethernet L34 headers]
+    queue shared thread(s)
+    0     yes    0-1
+  Ethernet address 02:fe:23:f0:88:99
+  Linux PACKET socket interface v3
+  FEATURES:
+    qdisc-bpass-enabled
+    cksum-gso-enabled
+  RX Queue 0:
+    block size:65536 nr:160  frame size:2048 nr:5120 next block:39
+  TX Queue 0:
+    block size:69206016 nr:1  frame size:67584 nr:1024 next frame:39
+    available:1024 request:0 sending:0 wrong:0 total:1024
+local0                             0    down  local0
+  Link speed: unknown
+  local
+
+```
+
+- Check flow table in dpapp
+```
+vpp# show dash flow
+     1: eni 00:cc:cc:cc:cc:cc, vnet_id 343, proto 17, 10.1.1.10 1234 -> 10.1.2.50 80
+        common data - version 0, direction 1, actions 0x9, timeout 28
+
+vpp# clear dash flow 1
+```
+
+- Check packet processing trace in dpapp
+```
+vpp# trace add af-packet-input 100
+vpp# show trace
+```
+
+On behalf of BMv2 switch, script `tools/send_p2a_pkt.py` can send packet with dash header to verify basic flow
+functionality of dpapp.
+
+## Test
+By default, flow lookup is not enabled in DASH pipeline. The decorator `@use_flow` will enable it and then involve dpapp
+for slow path. If test cases are verified to support flow, aka stateful packet processing, use the decorator to mark
+the test class.
+
+PTF test script [saidashdpapp_sanity.py](https://github.com/sonic-net/DASH/blob/main/test/test-cases/functional/ptf/saidashdpapp_sanity.py)
+provides sanity check for dpapp. Refer to it as a sample for new flow tests.

dash-pipeline/dpapp/dash/CMakeLists.txt

@@ -0,0 +1,36 @@
+# Copyright (c) 2018 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_directories(${CMAKE_SOURCE_DIR})
+
+# for generated API headers:
+include_directories(${CMAKE_BINARY_DIR})
+
+add_vpp_plugin(dash
+  SOURCES
+  dash.c
+  dash_node.c
+  flow.c
+  saiapi.c
+
+  MULTIARCH_SOURCES
+  dash_node.c
+
+  API_FILES
+  dash.api
+
+  API_TEST_SOURCES
+  dash_test.c
+
+  COMPONENT vpp-plugin-dash
+)

dash-pipeline/dpapp/dash/dash.api

@@ -0,0 +1,18 @@
+/* Define a simple binary API to control the feature */
+
+option version = "0.1.0";
+import "vnet/interface_types.api";
+
+autoreply define dash_enable_disable {
+  /* Client identifier, set from api_main.my_client_index */
+  u32 client_index;
+
+  /* Arbitrary context, so client can match reply to request */
+  u32 context;
+
+  /* Enable / disable the feature */
+  bool enable_disable;
+
+  /* Interface handle */
+  vl_api_interface_index_t sw_if_index;
+};