packet/parser: Add Checksum support (026a813b) · Commits · e / os / android_packages_modules_Bluetooth

system/gd/packet/parser/Android.bp

+3 −0

Original line number	Diff line number	Diff line
		@@ -2,6 +2,8 @@ cc_binary_host {
		name: "bluetooth_packetgen",
		srcs: [
		"fields/body_field.cc",
		"fields/checksum_field.cc",
		"fields/checksum_start_field.cc",
		"fields/custom_field.cc",
		"fields/enum_field.cc",
		"fields/fixed_field.cc",
		@@ -11,6 +13,7 @@ cc_binary_host {
		"fields/reserved_field.cc",
		"fields/scalar_field.cc",
		"fields/size_field.cc",
		"checksum_def.cc",
		"custom_field_def.cc",
		"enum_def.cc",
		"enum_gen.cc",

+8 −0

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		@@ -12,6 +12,13 @@ Packet Views and Builders
		extract the fields that are defined in the pdl file. Builders check the input
		arguments and can be serialized.

		Checksum types
		checksum MyChecksumClass : 16 "path/to/the/class/"
		Checksum fields need to implement the following three static methods:
		static void Initialize(MyChecksumClass&);
		static void AddByte(MyChecksumClass&, uint8_t);
		// Assuming a 16-bit (uint16_t) checksum:
		static uint16_t GetChecksum(MyChecksumClass&);
		-------------
		LIMITATIONS
		-------------
		@@ -27,6 +34,7 @@ Packet Views and Builders

		- Can't handle size for Body type fields yet since they might not be byte aligned.


		-------
		NOTES
		-------

0 → 100644

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		/*
		* Copyright 2019 The Android Open Source Project
		*
		* 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 "checksum_def.h"

		#include "util.h"

		ChecksumDef::ChecksumDef(std::string name, std::string include, int size) : CustomFieldDef(name, include, size) {}

		PacketField* ChecksumDef::GetNewField(const std::string& name, ParseLocation loc) const {
		return new ChecksumField(name, name_, size_, loc);
		}

		TypeDef::Type ChecksumDef::GetDefinitionType() const {
		return TypeDef::Type::CHECKSUM;
		}

		void ChecksumDef::GenInclude(std::ostream& s) const {
		CustomFieldDef::GenInclude(s);
		}

		void ChecksumDef::GenUsing(std::ostream& s) const {
		CustomFieldDef::GenUsing(s);
		}

		void ChecksumDef::GenChecksumCheck(std::ostream& s) const {
		s << "static_assert(ChecksumTypeChecker<" << name_ << "," << util::GetTypeForSize(size_) << ">::value, \"";
		s << name_ << " is not a valid checksum type. Please see README for more details.\");";
		}

0 → 100644

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		/*
		* Copyright 2019 The Android Open Source Project
		*
		* 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.
		*/

		#pragma once

		#include <iostream>

		#include "checksum_type_checker.h"
		#include "custom_field_def.h"
		#include "fields/checksum_field.h"
		#include "parse_location.h"
		#include "type_def.h"

		class ChecksumDef : public CustomFieldDef {
		public:
		ChecksumDef(std::string name, std::string include, int size);

		virtual PacketField* GetNewField(const std::string& name, ParseLocation loc) const override;

		virtual TypeDef::Type GetDefinitionType() const override;

		virtual void GenInclude(std::ostream& s) const override;

		virtual void GenUsing(std::ostream& s) const override;

		void GenChecksumCheck(std::ostream& s) const;

		const std::string include_;
		};

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		#include <optional>

		namespace bluetooth {
		namespace packet {
		namespace parser {

		// Checks for Initialize(), AddByte(), and GetChecksum().
		// T and TRET are the checksum class Type and the checksum return type
		// C and CRET are the substituted types for T and TRET
		template <typename T, typename TRET>
		class ChecksumTypeChecker {
		public:
		template <class C, void (*)(C&)>
		struct InitializeChecker {};

		template <class C, void (*)(C&, uint8_t byte)>
		struct AddByteChecker {};

		template <class C, typename CRET, CRET (*)(const C&)>
		struct GetChecksumChecker {};

		// If all the methods are defined, this one matches
		template <class C, typename CRET>
		static int Test(InitializeChecker<C, &C::Initialize>, AddByteChecker<C, &C::AddByte>,
		GetChecksumChecker<C, CRET, &C::GetChecksum>*);

		// This one matches everything else
		template <class C, typename CRET>
		static char Test(...);

		// This checks which template was matched
		static constexpr bool value = (sizeof(Test<T, TRET>(0, 0, 0)) == sizeof(int));
		};
		} // namespace parser
		} // namespace packet
		} // namespace bluetooth