Merge "Fix potential ApfFilter bugs by careful ByteBuffer use" into nyc-dev

        private static final int ICMP6_4_BYTE_LIFETIME_OFFSET = 4;

        private static final int ICMP6_4_BYTE_LIFETIME_LEN = 4;

        // Note: mPacket's position() cannot be assumed to be reset.

        private final ByteBuffer mPacket;

        // List of binary ranges that include the whole packet except the lifetimes.

        // Pairs consist of offset and length.

        // Ignoring lifetimes (which may change) does {@code packet} match this RA?

        boolean matches(byte[] packet, int length) {

            if (length != mPacket.limit()) return false;

            ByteBuffer a = ByteBuffer.wrap(packet);

            ByteBuffer b = mPacket;

            if (length != mPacket.capacity()) return false;

            byte[] referencePacket = mPacket.array();

            for (Pair<Integer, Integer> nonLifetime : mNonLifetimes) {

                a.clear();

                b.clear();

                a.position(nonLifetime.first);

                b.position(nonLifetime.first);

                a.limit(nonLifetime.first + nonLifetime.second);

                b.limit(nonLifetime.first + nonLifetime.second);

                if (a.compareTo(b) != 0) return false;

                for (int i = nonLifetime.first; i < (nonLifetime.first + nonLifetime.second); i++) {

                    if (packet[i] != referencePacket[i]) return false;

                }

            }

            return true;

        }

            String nextFilterLabel = "Ra" + getUniqueNumberLocked();

            // Skip if packet is not the right size

            gen.addLoadFromMemory(Register.R0, gen.PACKET_SIZE_MEMORY_SLOT);

            gen.addJumpIfR0NotEquals(mPacket.limit(), nextFilterLabel);

            gen.addJumpIfR0NotEquals(mPacket.capacity(), nextFilterLabel);

            int filterLifetime = (int)(currentLifetime() / FRACTION_OF_LIFETIME_TO_FILTER);

            // Skip filter if expired

            gen.addLoadFromMemory(Register.R0, gen.FILTER_AGE_MEMORY_SLOT);