Teach ApfGenerator about the new opcodes for accessing data memory (408dbda4) · Commits · e / os / android_frameworks_base

services/net/java/android/net/apf/ApfFilter.java

+4 −5

Original line number	Diff line number	Diff line
		@@ -522,7 +522,7 @@ public class ApfFilter {
		ICMP6_4_BYTE_LIFETIME_OFFSET, ICMP6_4_BYTE_LIFETIME_LEN);
		}

		// Note that this parses RA and may throw IllegalArgumentException (from
		// Note that this parses RA and may throw InvalidRaException (from
		// Buffer.position(int) or due to an invalid-length option) or IndexOutOfBoundsException
		// (from ByteBuffer.get(int) ) if parsing encounters something non-compliant with
		// specifications.
		@@ -986,9 +986,8 @@ public class ApfFilter {
		*/
		@GuardedBy("this")
		private ApfGenerator beginProgramLocked() throws IllegalInstructionException {
		ApfGenerator gen = new ApfGenerator();
		// This is guaranteed to return true because of the check in maybeCreate.
		gen.setApfVersion(mApfCapabilities.apfVersionSupported);
		// This is guaranteed to succeed because of the check in maybeCreate.
		ApfGenerator gen = new ApfGenerator(mApfCapabilities.apfVersionSupported);

		// Here's a basic summary of what the initial program does:
		//
		@@ -1216,7 +1215,7 @@ public class ApfFilter {
		// 1. the program generator will need its offsets adjusted.
		// 2. the packet filter attached to our packet socket will need its offset adjusted.
		if (apfCapabilities.apfPacketFormat != ARPHRD_ETHER) return null;
		if (!new ApfGenerator().setApfVersion(apfCapabilities.apfVersionSupported)) {
		if (!ApfGenerator.supportsVersion(apfCapabilities.apfVersionSupported)) {
		Log.e(TAG, "Unsupported APF version: " + apfCapabilities.apfVersionSupported);
		return null;
		}

services/net/java/android/net/apf/ApfGenerator.java

+57 −6

Original line number	Diff line number	Diff line
		@@ -58,7 +58,9 @@ public class ApfGenerator {
		JLT(18), // Compare less than and branch, e.g. "jlt R0,5,label"
		JSET(19), // Compare any bits set and branch, e.g. "jset R0,5,label"
		JNEBS(20), // Compare not equal byte sequence, e.g. "jnebs R0,5,label,0x1122334455"
		EXT(21); // Followed by immediate indicating ExtendedOpcodes.
		EXT(21), // Followed by immediate indicating ExtendedOpcodes.
		LDDW(22), // Load 4 bytes from data memory address (register + immediate): "lddw R0, [5]R1"
		STDW(23); // Store 4 bytes to data memory address (register + immediate): "stdw R0, [5]R1"

		final int value;

		@@ -355,19 +357,38 @@ public class ApfGenerator {
		*/
		public static final int LAST_PREFILLED_MEMORY_SLOT = FILTER_AGE_MEMORY_SLOT;

		// This version number syncs up with APF_VERSION in hardware/google/apf/apf_interpreter.h
		private static final int MIN_APF_VERSION = 2;

		private final ArrayList<Instruction> mInstructions = new ArrayList<Instruction>();
		private final HashMap<String, Instruction> mLabels = new HashMap<String, Instruction>();
		private final Instruction mDropLabel = new Instruction(Opcodes.LABEL);
		private final Instruction mPassLabel = new Instruction(Opcodes.LABEL);
		private final int mVersion;
		private boolean mGenerated;

		/**
		* Set version of APF instruction set to generate instructions for. Returns {@code true}
		* if generating for this version is supported, {@code false} otherwise.
		* Creates an ApfGenerator instance which is able to emit instructions for the specified
		* {@code version} of the APF interpreter. Throws {@code IllegalInstructionException} if
		* the requested version is unsupported.
		*/
		public boolean setApfVersion(int version) {
		// This version number syncs up with APF_VERSION in hardware/google/apf/apf_interpreter.h
		return version >= 2;
		ApfGenerator(int version) throws IllegalInstructionException {
		mVersion = version;
		requireApfVersion(MIN_APF_VERSION);
		}

		/**
		* Returns true if the specified {@code version} is supported by the ApfGenerator, otherwise
		* false.
		*/
		public static boolean supportsVersion(int version) {
		return version >= MIN_APF_VERSION;
		}

		private void requireApfVersion(int minimumVersion) throws IllegalInstructionException {
		if (mVersion < minimumVersion) {
		throw new IllegalInstructionException("Requires APF >= " + minimumVersion);
		}
		}

		private void addInstruction(Instruction instruction) {
		@@ -818,6 +839,36 @@ public class ApfGenerator {
		return this;
		}

		/**
		* Add an instruction to the end of the program to load 32 bits from the data memory into
		* {@code register}. The source address is computed by adding @{code offset} to the other
		* register.
		* Requires APF v3 or greater.
		*/
		public ApfGenerator addLoadData(Register destinationRegister, int offset)
		throws IllegalInstructionException {
		requireApfVersion(3);
		Instruction instruction = new Instruction(Opcodes.LDDW, destinationRegister);
		instruction.setUnsignedImm(offset);
		addInstruction(instruction);
		return this;
		}

		/**
		* Add an instruction to the end of the program to store 32 bits from {@code register} into the
		* data memory. The destination address is computed by adding @{code offset} to the other
		* register.
		* Requires APF v3 or greater.
		*/
		public ApfGenerator addStoreData(Register sourceRegister, int offset)
		throws IllegalInstructionException {
		requireApfVersion(3);
		Instruction instruction = new Instruction(Opcodes.STDW, sourceRegister);
		instruction.setUnsignedImm(offset);
		addInstruction(instruction);
		return this;
		}

		/**
		* Updates instruction offset fields using latest instruction sizes.
		* @return current program length in bytes.

tests/net/java/android/net/apf/ApfTest.java

+223 −84

File changed.

Preview size limit exceeded, changes collapsed.

tests/net/java/android/net/apf/Bpf2Apf.java

+2 −2

Original line number	Diff line number	Diff line
		@@ -307,7 +307,7 @@ public class Bpf2Apf {
		* program and return it.
		*/
		public static byte[] convert(String bpf) throws IllegalInstructionException {
		ApfGenerator gen = new ApfGenerator();
		ApfGenerator gen = new ApfGenerator(3);
		for (String line : bpf.split("\\n")) convertLine(line, gen);
		return gen.generate();
		}
		@@ -320,7 +320,7 @@ public class Bpf2Apf {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String line = null;
		StringBuilder responseData = new StringBuilder();
		ApfGenerator gen = new ApfGenerator();
		ApfGenerator gen = new ApfGenerator(3);
		while ((line = in.readLine()) != null) convertLine(line, gen);
		System.out.write(gen.generate());
		}

tests/net/jni/apf_jni.cpp

+18 −11

Original line number	Diff line number	Diff line
		/*
		* Copyright 2016, The Android Open Source Project
		* Copyright 2018, 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.
		@@ -28,15 +28,22 @@

		// JNI function acting as simply call-through to native APF interpreter.
		static jint com_android_server_ApfTest_apfSimulate(
		JNIEnv* env, jclass, jbyteArray program, jbyteArray packet, jint filter_age) {
		return accept_packet(
		(uint8_t*)env->GetByteArrayElements(program, NULL),
		env->GetArrayLength(program),
		(uint8_t*)env->GetByteArrayElements(packet, NULL),
		env->GetArrayLength(packet),
		nullptr,
		0,
		filter_age);
		JNIEnv* env, jclass, jbyteArray program, jbyteArray packet,
		jbyteArray data, jint filter_age) {
		uint8_t* program_raw = (uint8_t*)env->GetByteArrayElements(program, nullptr);
		uint8_t* packet_raw = (uint8_t*)env->GetByteArrayElements(packet, nullptr);
		uint8_t* data_raw = (uint8_t*)(data ? env->GetByteArrayElements(data, nullptr) : nullptr);
		uint32_t program_len = env->GetArrayLength(program);
		uint32_t packet_len = env->GetArrayLength(packet);
		uint32_t data_len = data ? env->GetArrayLength(data) : 0;
		jint result = accept_packet(program_raw, program_len, packet_raw,
		packet_len, data_raw, data_len, filter_age);
		if (data) {
		env->ReleaseByteArrayElements(data, (jbyte)data_raw, 0 / copy back */);
		}
		env->ReleaseByteArrayElements(packet, (jbyte*)packet_raw, JNI_ABORT);
		env->ReleaseByteArrayElements(program, (jbyte*)program_raw, JNI_ABORT);
		return result;
		}

		class ScopedPcap {
		@@ -170,7 +177,7 @@ extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
		}

		static JNINativeMethod gMethods[] = {
		{ "apfSimulate", "([B[BI)I",
		{ "apfSimulate", "([B[B[BI)I",
		(void*)com_android_server_ApfTest_apfSimulate },
		{ "compileToBpf", "(Ljava/lang/String;)Ljava/lang/String;",
		(void*)com_android_server_ApfTest_compileToBpf },