p4c-ubpf: new uBPF back-end for p4c (#2134)

p4c-ubpf back-end

.travis.yml

@@ -41,4 +41,4 @@ install:
 
 script:
   - if [[ $TRAVIS_OS_NAME == 'linux' && $UNIFIED == ON ]] ; then docker run -w /p4c/build -e CTEST_PARALLEL_LEVEL p4c ctest --output-on-failure --schedule-random ; fi
-  - if [[ $TRAVIS_OS_NAME == 'osx' && $UNIFIED == ON ]] ; then ctest --output-on-failure -j 2 --schedule-random -LE "ebpf$" ; fi
+  - if [[ $TRAVIS_OS_NAME == 'osx' && $UNIFIED == ON ]] ; then ctest --output-on-failure -j 2 --schedule-random -LE "bpf$" ; fi

CMakeLists.txt

@@ -32,6 +32,7 @@ OPTION (ENABLE_DOCS "Build the documentation" OFF)
 OPTION (ENABLE_GTESTS "Enable building and running GTest unit tests" ON)
 OPTION (ENABLE_BMV2 "Build the BMV2 backend (required for the full test suite)" ON)
 OPTION (ENABLE_EBPF "Build the EBPF backend (required for the full test suite)" ON)
+OPTION (ENABLE_UBPF "Build the uBPF backend (required for the full test suite)" ON)
 OPTION (ENABLE_P4TEST "Build the P4Test backend (required for the full test suite)" ON)
 OPTION (ENABLE_P4C_GRAPHS "Build the p4c-graphs backend" ON)
 OPTION (ENABLE_PROTOBUF_STATIC "Link against Protobuf statically" ON)
@@ -277,6 +278,9 @@ endif ()
 if (ENABLE_EBPF)
     add_subdirectory (backends/ebpf)
 endif ()
+if (ENABLE_UBPF)
+    add_subdirectory (backends/ubpf)
+endif ()
 if (ENABLE_P4TEST)
     add_subdirectory (backends/p4test)
 endif ()

backends/ebpf/midend.h

@@ -25,8 +25,8 @@ limitations under the License.
 namespace EBPF {
 
 class MidEnd {
-    std::vector<DebugHook> hooks;
  public:
+    std::vector<DebugHook> hooks;
     P4::ReferenceMap       refMap;
     P4::TypeMap            typeMap;
 

backends/ebpf/targets/ubpf_target.py

@@ -0,0 +1 @@
+../../ubpf/targets/ubpf_target.py

backends/ubpf/CMakeLists.txt

@@ -0,0 +1,85 @@
+# Copyright 2019 Orange
+#
+# 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.
+
+# CMakefile for the uBPF P4-16 backend.
+
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/version.h.cmake"
+        "${CMAKE_CURRENT_BINARY_DIR}/version.h" @ONLY)
+
+set(P4C_UBPF_SOURCES
+        p4c-ubpf.cpp
+        ubpfBackend.cpp
+        ubpfProgram.cpp
+        ubpfParser.cpp
+        ubpfDeparser.cpp
+        ubpfControl.cpp
+        ubpfType.cpp
+        ubpfTable.cpp
+        ubpfRegister.cpp
+        ubpfModel.cpp
+        target.cpp
+        midend.cpp
+        ../../backends/ebpf/ebpfProgram.cpp
+        ../../backends/ebpf/ebpfTable.cpp
+        ../../backends/ebpf/ebpfParser.cpp
+        ../../backends/ebpf/ebpfControl.cpp
+        ../../backends/ebpf/ebpfOptions.cpp
+        ../../backends/ebpf/target.cpp
+        ../../backends/ebpf/codeGen.cpp
+        ../../backends/ebpf/ebpfType.cpp
+        ../../backends/ebpf/ebpfModel.cpp
+        ../../backends/ebpf/midend.cpp
+        ../../backends/ebpf/lower.cpp)
+
+set(P4C_UBPF_HEADERS
+        codeGen.h
+        ubpfProgram.h
+        ubpfType.h
+        ubpfParser.h
+        ubpfDeparser.h
+        ubpfControl.h
+        ubpfRegister.h
+        ubpfModel.h
+        target.h
+        midend.h
+        ubpfBackend.h)
+
+set (P4C_UBPF_DIST_HEADERS p4include/ubpf_model.p4)
+
+add_cpplint_files(${CMAKE_CURRENT_SOURCE_DIR} "$(P4C_UBPF_SOURCES)")
+
+build_unified(P4C_UBPF_SOURCES ALL)
+add_executable(p4c-ubpf ${P4C_UBPF_SOURCES})
+target_link_libraries (p4c-ubpf ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+add_dependencies(p4c-ubpf genIR frontend)
+
+install (TARGETS p4c-ubpf
+        RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})
+install (DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/p4include
+        DESTINATION ${P4C_ARTIFACTS_OUTPUT_DIRECTORY})
+
+
+add_custom_target(linkp4cubpf
+        COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_CURRENT_BINARY_DIR}/p4c-ubpf ${P4C_BINARY_DIR}/p4c-ubpf
+        COMMAND ${CMAKE_COMMAND} -E make_directory ${P4C_BINARY_DIR}/p4include &&
+        ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/${P4C_UBPF_DIST_HEADERS} ${P4C_BINARY_DIR}/p4include
+        COMMAND ${CMAKE_COMMAND} -E create_symlink ${P4C_BINARY_DIR}/p4include ${CMAKE_CURRENT_BINARY_DIR}/p4include
+        )
+
+add_dependencies(p4c_driver linkp4cubpf)
+
+set(UBPF_DRIVER "${CMAKE_CURRENT_SOURCE_DIR}/run-ubpf-test.py -t ubpf -c \"${P4C_BINARY_DIR}/p4c-ubpf\"")
+set (UBPF_TEST_SUITES ${P4C_SOURCE_DIR}/testdata/p4_16_samples/*_ubpf.p4)
+set (UBPF_XFAIL_TESTS)
+p4c_add_tests("ubpf" ${UBPF_DRIVER} "${UBPF_TEST_SUITES}" "${UBPF_XFAIL_TESTS}")

backends/ubpf/README.md

@@ -0,0 +1,82 @@
+# Introduction to uBPF Backend
+
+The **p4c-ubpf** compiler allows to translate P4 programs into the uBPF programs. We use the uBPF implementation provided 
+by [the P4rt-OVS switch](https://github.com/Orange-OpenSource/p4rt-ovs). The uBPF VM is based on the
+open-source implementation provided by [IOVisor](https://github.com/iovisor/ubpf).
+
+The P4-to-uBPF compiler accepts only the P4_16 programs written for the [ubpf_model.p4](../ubpf/p4include/ubpf_model.p4) architecture model.
+
+The backend for uBPF is mostly based on [P4-to-eBPF compiler](../ebpf/README.md). In fact, it implements the same concepts, but
+generates C code, which is compatible with the user space BPF implementation. 
+
+## Background
+
+### P4
+
+Please, refer to [the overview of P4 written in eBPF Backend](../ebpf#p4).
+
+### uBPF
+
+**Why uBPF?** The uBPF Virtual Machine can be used in any solution implementing the kernel bypass (e.g. DPDK apps).
+
+The uBPF project re-implements the [eBPF](../ebpf#ebpf) kernel-based Virtual Machine. While the BPF programs are 
+intented to run in the kernel, the uBPF project enables running the BPF programs in user-space applications. It contains 
+eBPF assembler, disassembler, interpreter, and JIT compiler for x86-64.
+
+Moreover, contrary to the eBPF implementation, uBPF is not licensed under GPL. The uBPF implementation is licensed under
+Apache License, version 2.0. 
+
+## Compiling P4 to uBPF
+
+The scope of the uBPF backend is wider than the scope of the eBPF backend. Except for simple packet filtering the 
+P4-to-uBPF compiler supports also P4 registers and programmable actions including packet's modifications and tunneling. For further details
+refer to [uBPF architecture model](p4include/ubpf_model.p4).
+
+The current version of the P4-to-uBPF compiler translates P4_16 programs to programs written in the C language. This
+program is compatible with the uBPF VM and the `clang` compiler can be used to generate uBPF bytecode.
+
+### Translation between P4 and C
+
+We follow the convention of the P4-to-eBPF compiler so the parser translation is presented in the table 
+[Translating parsers](../ebpf#translating-parsers) from P4-to-eBPF. The translation of match-action pipelines is presented
+in the [Translating match-action pipelines](../ebpf#translating-match-action-pipelines) table from P4-to-eBPF.
+
+However, we introduced some modifications, which are listed below:
+
+* The generated code uses user-level data types (e.g. uint8_t, etc.). 
+* Methods to extract packet fields (e.g. load_dword, etc.) have been re-implemented to use user-space data types.
+* The uBPF helpers are imported into the C programs.
+* We have added `mark_to_drop()` extern to the `ubpf` model, so that packets to drop are marked in the P4-native way.
+* We have added support for P4 registers implemented as BPF maps
+
+### How to use?
+
+The sample P4 programs are located in `examples/` directory. We have tested them with the [P4rt-OVS](https://github.com/Orange-OpenSource/p4rt-ovs) switch - 
+the Open vSwitch that can be extended with BPF programs at runtime. See [the detailed tutorial](./docs/EXAMPLES.md) on how to run and test those examples.
+
+In order to generate the C code use the following command:
+
+`p4c-ubpf PROGRAM.p4 -o out.c`
+
+This command will generate out.c and the corresponding out.h file containing definitions of the packet structures and BPF maps.
+
+Once the C program is generated it can be compiled using:
+
+`clang -O2 -target bpf -c out.c -o /tmp/out.o`
+
+The output file (`out.o`) can be injected to the uBPF VM. 
+
+### Known limitations
+
+* No support for some P4 constructs (meters, counters, etc.)
+
+### Contact
+
+Tomasz Osiński <[email protected]>
+
+Mateusz Kossakowski <[email protected]>
+
+
+
+
+

backends/ubpf/codeGen.h

@@ -0,0 +1,17 @@
+#ifndef P4C_CODEGEN_H
+#define P4C_CODEGEN_H
+
+#include "lib/sourceCodeBuilder.h"
+#include "ebpf/codeGen.h"
+#include "target.h"
+
+namespace UBPF {
+    class UbpfCodeBuilder : public EBPF::CodeBuilder {
+    public:
+        const UbpfTarget *target;
+        explicit UbpfCodeBuilder(const UbpfTarget *target) : EBPF::CodeBuilder(target), target(target) {}
+    };
+}
+
+
+#endif //P4C_CODEGEN_H