diff --git a/packages/NetworkStack/src/android/net/apf/ApfFilter.java b/packages/NetworkStack/src/android/net/apf/ApfFilter.java index 3dd90eeff767a..d2f32591cbbe4 100644 --- a/packages/NetworkStack/src/android/net/apf/ApfFilter.java +++ b/packages/NetworkStack/src/android/net/apf/ApfFilter.java @@ -74,6 +74,7 @@ import java.net.SocketException; import java.net.UnknownHostException; import java.nio.BufferUnderflowException; import java.nio.ByteBuffer; +import java.nio.ByteOrder; import java.util.ArrayList; import java.util.Arrays; @@ -282,6 +283,7 @@ public class ApfFilter { private static final byte[] ETH_BROADCAST_MAC_ADDRESS = {(byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff }; // TODO: Make these offsets relative to end of link-layer header; don't include ETH_HEADER_LEN. + private static final int IPV4_TOTAL_LENGTH_OFFSET = ETH_HEADER_LEN + 2; private static final int IPV4_FRAGMENT_OFFSET_OFFSET = ETH_HEADER_LEN + 6; // Endianness is not an issue for this constant because the APF interpreter always operates in // network byte order. @@ -881,10 +883,23 @@ public class ApfFilter { protected final TcpKeepaliveAckData mPacket; protected final byte[] mSrcDstAddr; + protected final byte[] mPortSeqAckFingerprint; TcpKeepaliveAck(final TcpKeepaliveAckData packet, final byte[] srcDstAddr) { mPacket = packet; mSrcDstAddr = srcDstAddr; + mPortSeqAckFingerprint = generatePortSeqAckFingerprint(mPacket.srcPort, + mPacket.dstPort, mPacket.seq, mPacket.ack); + } + + static byte[] generatePortSeqAckFingerprint(int srcPort, int dstPort, int seq, int ack) { + final ByteBuffer fp = ByteBuffer.allocate(12); + fp.order(ByteOrder.BIG_ENDIAN); + fp.putShort((short) srcPort); + fp.putShort((short) dstPort); + fp.putInt(seq); + fp.putInt(ack); + return fp.array(); } static byte[] concatArrays(final byte[]... arr) { @@ -919,10 +934,6 @@ public class ApfFilter { private class TcpKeepaliveAckV4 extends TcpKeepaliveAck { private static final int IPV4_SRC_ADDR_OFFSET = IP_HEADER_OFFSET + 12; - private static final int IPV4_TCP_SRC_PORT_OFFSET = 0; - private static final int IPV4_TCP_DST_PORT_OFFSET = 2; - private static final int IPV4_TCP_SEQ_OFFSET = 4; - private static final int IPV4_TCP_ACK_OFFSET = 8; TcpKeepaliveAckV4(final TcpKeepalivePacketDataParcelable sentKeepalivePacket) { this(new TcpKeepaliveAckData(sentKeepalivePacket)); @@ -934,12 +945,12 @@ public class ApfFilter { @Override void generateFilterLocked(ApfGenerator gen) throws IllegalInstructionException { final String nextFilterLabel = "keepalive_ack" + getUniqueNumberLocked(); - gen.addLoad8(Register.R0, IPV4_PROTOCOL_OFFSET); - gen.addJumpIfR0NotEquals(IPPROTO_TCP, nextFilterLabel); + gen.addLoadImmediate(Register.R0, ETH_HEADER_LEN + IPV4_SRC_ADDR_OFFSET); gen.addJumpIfBytesNotEqual(Register.R0, mSrcDstAddr, nextFilterLabel); - // Pass the packet if it's not zero-sized : + // Skip to the next filter if it's not zero-sized : + // TCP_HEADER_SIZE + IPV4_HEADER_SIZE - ipv4_total_length == 0 // Load the IP header size into R1 gen.addLoadFromMemory(Register.R1, gen.IPV4_HEADER_SIZE_MEMORY_SLOT); // Load the TCP header size into R0 (it's indexed by R1) @@ -947,27 +958,18 @@ public class ApfFilter { // Size offset is in the top nibble, but it must be multiplied by 4, and the two // top bits of the low nibble are guaranteed to be zeroes. Right-shift R0 by 2. gen.addRightShift(2); - // R0 += R1 -> R0 contains TCP + IP headers lenght + // R0 += R1 -> R0 contains TCP + IP headers length gen.addAddR1(); - // Add the Ethernet header length to R0. - gen.addLoadImmediate(Register.R1, ETH_HEADER_LEN); - gen.addAddR1(); - // Compare total length of headers to the size of the packet. - gen.addLoadFromMemory(Register.R1, gen.PACKET_SIZE_MEMORY_SLOT); + // Load IPv4 total length + gen.addLoad16(Register.R1, IPV4_TOTAL_LENGTH_OFFSET); gen.addNeg(Register.R0); gen.addAddR1(); gen.addJumpIfR0NotEquals(0, nextFilterLabel); - // Add IPv4 header length gen.addLoadFromMemory(Register.R1, gen.IPV4_HEADER_SIZE_MEMORY_SLOT); - gen.addLoad16Indexed(Register.R0, ETH_HEADER_LEN + IPV4_TCP_SRC_PORT_OFFSET); - gen.addJumpIfR0NotEquals(mPacket.srcPort, nextFilterLabel); - gen.addLoad16Indexed(Register.R0, ETH_HEADER_LEN + IPV4_TCP_DST_PORT_OFFSET); - gen.addJumpIfR0NotEquals(mPacket.dstPort, nextFilterLabel); - gen.addLoad32Indexed(Register.R0, ETH_HEADER_LEN + IPV4_TCP_SEQ_OFFSET); - gen.addJumpIfR0NotEquals(mPacket.seq, nextFilterLabel); - gen.addLoad32Indexed(Register.R0, ETH_HEADER_LEN + IPV4_TCP_ACK_OFFSET); - gen.addJumpIfR0NotEquals(mPacket.ack, nextFilterLabel); + gen.addLoadImmediate(Register.R0, ETH_HEADER_LEN); + gen.addAddR1(); + gen.addJumpIfBytesNotEqual(Register.R0, mPortSeqAckFingerprint, nextFilterLabel); maybeSetupCounter(gen, Counter.DROPPED_IPV4_KEEPALIVE_ACK); gen.addJump(mCountAndDropLabel); @@ -1169,9 +1171,10 @@ public class ApfFilter { gen.addJumpIfR0Equals(broadcastAddr, mCountAndDropLabel); } - // If any keepalive filters, - generateKeepaliveFilter(gen); + // If any keepalive filter matches, drop + generateV4KeepaliveFilters(gen); + // Otherwise, this is an IPv4 unicast, pass // If L2 broadcast packet, drop. // TODO: can we invert this condition to fall through to the common pass case below? maybeSetupCounter(gen, Counter.PASSED_IPV4_UNICAST); @@ -1180,7 +1183,7 @@ public class ApfFilter { maybeSetupCounter(gen, Counter.DROPPED_IPV4_L2_BROADCAST); gen.addJump(mCountAndDropLabel); } else { - generateKeepaliveFilter(gen); + generateV4KeepaliveFilters(gen); } // Otherwise, pass @@ -1188,12 +1191,25 @@ public class ApfFilter { gen.addJump(mCountAndPassLabel); } - private void generateKeepaliveFilter(ApfGenerator gen) throws IllegalInstructionException { + private void generateV4KeepaliveFilters(ApfGenerator gen) throws IllegalInstructionException { + final String skipV4KeepaliveFilter = "skip_v4_keepalive_filter"; + final boolean haveV4KeepaliveAcks = NetworkStackUtils.any(mKeepaliveAcks, + ack -> ack instanceof TcpKeepaliveAckV4); + + // If no keepalive acks + if (!haveV4KeepaliveAcks) return; + + // If not tcp, skip keepalive filters + gen.addLoad8(Register.R0, IPV4_PROTOCOL_OFFSET); + gen.addJumpIfR0NotEquals(IPPROTO_TCP, skipV4KeepaliveFilter); + // Drop IPv4 Keepalive acks for (int i = 0; i < mKeepaliveAcks.size(); ++i) { final TcpKeepaliveAck ack = mKeepaliveAcks.valueAt(i); if (ack instanceof TcpKeepaliveAckV4) ack.generateFilterLocked(gen); } + + gen.defineLabel(skipV4KeepaliveFilter); } /** @@ -1244,11 +1260,14 @@ public class ApfFilter { maybeSetupCounter(gen, Counter.DROPPED_IPV6_NON_ICMP_MULTICAST); gen.addLoad8(Register.R0, IPV6_DEST_ADDR_OFFSET); gen.addJumpIfR0Equals(0xff, mCountAndDropLabel); + // If any keepalive filter matches, drop + generateV6KeepaliveFilters(gen); // Not multicast. Pass. maybeSetupCounter(gen, Counter.PASSED_IPV6_UNICAST_NON_ICMP); gen.addJump(mCountAndPassLabel); gen.defineLabel(skipIPv6MulticastFilterLabel); } else { + generateV6KeepaliveFilters(gen); // If not ICMPv6, pass. maybeSetupCounter(gen, Counter.PASSED_IPV6_NON_ICMP); gen.addJumpIfR0NotEquals(IPPROTO_ICMPV6, mCountAndPassLabel); @@ -1272,12 +1291,27 @@ public class ApfFilter { maybeSetupCounter(gen, Counter.DROPPED_IPV6_MULTICAST_NA); gen.addJump(mCountAndDropLabel); gen.defineLabel(skipUnsolicitedMulticastNALabel); + } + + private void generateV6KeepaliveFilters(ApfGenerator gen) throws IllegalInstructionException { + final String skipV6KeepaliveFilter = "skip_v6_keepalive_filter"; + final boolean haveV6KeepaliveAcks = NetworkStackUtils.any(mKeepaliveAcks, + ack -> ack instanceof TcpKeepaliveAckV6); + + // If no keepalive acks + if (!haveV6KeepaliveAcks) return; + + // If not tcp, skip keepalive filters + gen.addLoad8(Register.R0, IPV6_NEXT_HEADER_OFFSET); + gen.addJumpIfR0NotEquals(IPPROTO_TCP, skipV6KeepaliveFilter); // Drop IPv6 Keepalive acks for (int i = 0; i < mKeepaliveAcks.size(); ++i) { final TcpKeepaliveAck ack = mKeepaliveAcks.valueAt(i); if (ack instanceof TcpKeepaliveAckV6) ack.generateFilterLocked(gen); } + + gen.defineLabel(skipV6KeepaliveFilter); } /** @@ -1294,6 +1328,8 @@ public class ApfFilter { *