| /* |
| * Copyright (C) 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. |
| * 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. |
| */ |
| |
| package android.net.ipmemorystore; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| |
| import java.net.Inet4Address; |
| import java.net.InetAddress; |
| import java.net.UnknownHostException; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Objects; |
| import java.util.StringJoiner; |
| |
| /** |
| * A POD object to represent attributes of a single L2 network entry. |
| * @hide |
| */ |
| public class NetworkAttributes { |
| private static final boolean DBG = true; |
| |
| // Weight cutoff for grouping. To group, a similarity score is computed with the following |
| // algorithm : if both fields are non-null and equals() then add their assigned weight, else if |
| // both are null then add a portion of their assigned weight (see NULL_MATCH_WEIGHT), |
| // otherwise add nothing. |
| // As a guideline, this should be something like 60~75% of the total weights in this class. The |
| // design states "in essence a reader should imagine that if two important columns don't match, |
| // or one important and several unimportant columns don't match then the two records are |
| // considered a different group". |
| private static final float TOTAL_WEIGHT_CUTOFF = 520.0f; |
| // The portion of the weight that is earned when scoring group-sameness by having both columns |
| // being null. This is because some networks rightfully don't have some attributes (e.g. a |
| // V6-only network won't have an assigned V4 address) and both being null should count for |
| // something, but attributes may also be null just because data is unavailable. |
| private static final float NULL_MATCH_WEIGHT = 0.25f; |
| |
| // The v4 address that was assigned to this device the last time it joined this network. |
| // This typically comes from DHCP but could be something else like static configuration. |
| // This does not apply to IPv6. |
| // TODO : add a list of v6 prefixes for the v6 case. |
| @Nullable |
| public final Inet4Address assignedV4Address; |
| private static final float WEIGHT_ASSIGNEDV4ADDR = 300.0f; |
| |
| // Optionally supplied by the client if it has an opinion on L3 network. For example, this |
| // could be a hash of the SSID + security type on WiFi. |
| @Nullable |
| public final String groupHint; |
| private static final float WEIGHT_GROUPHINT = 300.0f; |
| |
| // The list of DNS server addresses. |
| @Nullable |
| public final List<InetAddress> dnsAddresses; |
| private static final float WEIGHT_DNSADDRESSES = 200.0f; |
| |
| // The mtu on this network. |
| @Nullable |
| public final Integer mtu; |
| private static final float WEIGHT_MTU = 50.0f; |
| |
| // The sum of all weights in this class. Tests ensure that this stays equal to the total of |
| // all weights. |
| /** @hide */ |
| @VisibleForTesting |
| public static final float TOTAL_WEIGHT = WEIGHT_ASSIGNEDV4ADDR |
| + WEIGHT_GROUPHINT |
| + WEIGHT_DNSADDRESSES |
| + WEIGHT_MTU; |
| |
| /** @hide */ |
| @VisibleForTesting |
| public NetworkAttributes( |
| @Nullable final Inet4Address assignedV4Address, |
| @Nullable final String groupHint, |
| @Nullable final List<InetAddress> dnsAddresses, |
| @Nullable final Integer mtu) { |
| if (mtu != null && mtu < 0) throw new IllegalArgumentException("MTU can't be negative"); |
| this.assignedV4Address = assignedV4Address; |
| this.groupHint = groupHint; |
| this.dnsAddresses = null == dnsAddresses ? null : |
| Collections.unmodifiableList(new ArrayList<>(dnsAddresses)); |
| this.mtu = mtu; |
| } |
| |
| @VisibleForTesting |
| public NetworkAttributes(@NonNull final NetworkAttributesParcelable parcelable) { |
| // The call to the other constructor must be the first statement of this constructor, |
| // so everything has to be inline |
| this((Inet4Address) getByAddressOrNull(parcelable.assignedV4Address), |
| parcelable.groupHint, |
| blobArrayToInetAddressList(parcelable.dnsAddresses), |
| parcelable.mtu >= 0 ? parcelable.mtu : null); |
| } |
| |
| @Nullable |
| private static InetAddress getByAddressOrNull(@Nullable final byte[] address) { |
| try { |
| return InetAddress.getByAddress(address); |
| } catch (UnknownHostException e) { |
| return null; |
| } |
| } |
| |
| @Nullable |
| private static List<InetAddress> blobArrayToInetAddressList(@Nullable final Blob[] blobs) { |
| if (null == blobs) return null; |
| final ArrayList<InetAddress> list = new ArrayList<>(blobs.length); |
| for (final Blob b : blobs) { |
| final InetAddress addr = getByAddressOrNull(b.data); |
| if (null != addr) list.add(addr); |
| } |
| return list; |
| } |
| |
| @Nullable |
| private static Blob[] inetAddressListToBlobArray(@Nullable final List<InetAddress> addresses) { |
| if (null == addresses) return null; |
| final ArrayList<Blob> blobs = new ArrayList<>(); |
| for (int i = 0; i < addresses.size(); ++i) { |
| final InetAddress addr = addresses.get(i); |
| if (null == addr) continue; |
| final Blob b = new Blob(); |
| b.data = addr.getAddress(); |
| blobs.add(b); |
| } |
| return blobs.toArray(new Blob[0]); |
| } |
| |
| /** Converts this NetworkAttributes to a parcelable object */ |
| @NonNull |
| public NetworkAttributesParcelable toParcelable() { |
| final NetworkAttributesParcelable parcelable = new NetworkAttributesParcelable(); |
| parcelable.assignedV4Address = |
| (null == assignedV4Address) ? null : assignedV4Address.getAddress(); |
| parcelable.groupHint = groupHint; |
| parcelable.dnsAddresses = inetAddressListToBlobArray(dnsAddresses); |
| parcelable.mtu = (null == mtu) ? -1 : mtu; |
| return parcelable; |
| } |
| |
| private float samenessContribution(final float weight, |
| @Nullable final Object o1, @Nullable final Object o2) { |
| if (null == o1) { |
| return (null == o2) ? weight * NULL_MATCH_WEIGHT : 0f; |
| } |
| return Objects.equals(o1, o2) ? weight : 0f; |
| } |
| |
| /** @hide */ |
| public float getNetworkGroupSamenessConfidence(@NonNull final NetworkAttributes o) { |
| final float samenessScore = |
| samenessContribution(WEIGHT_ASSIGNEDV4ADDR, assignedV4Address, o.assignedV4Address) |
| + samenessContribution(WEIGHT_GROUPHINT, groupHint, o.groupHint) |
| + samenessContribution(WEIGHT_DNSADDRESSES, dnsAddresses, o.dnsAddresses) |
| + samenessContribution(WEIGHT_MTU, mtu, o.mtu); |
| // The minimum is 0, the max is TOTAL_WEIGHT and should be represented by 1.0, and |
| // TOTAL_WEIGHT_CUTOFF should represent 0.5, but there is no requirement that |
| // TOTAL_WEIGHT_CUTOFF would be half of TOTAL_WEIGHT (indeed, it should not be). |
| // So scale scores under the cutoff between 0 and 0.5, and the scores over the cutoff |
| // between 0.5 and 1.0. |
| if (samenessScore < TOTAL_WEIGHT_CUTOFF) { |
| return samenessScore / (TOTAL_WEIGHT_CUTOFF * 2); |
| } else { |
| return (samenessScore - TOTAL_WEIGHT_CUTOFF) / (TOTAL_WEIGHT - TOTAL_WEIGHT_CUTOFF) / 2 |
| + 0.5f; |
| } |
| } |
| |
| /** @hide */ |
| public static class Builder { |
| @Nullable |
| private Inet4Address mAssignedAddress; |
| @Nullable |
| private String mGroupHint; |
| @Nullable |
| private List<InetAddress> mDnsAddresses; |
| @Nullable |
| private Integer mMtu; |
| |
| /** |
| * Set the assigned address. |
| * @param assignedV4Address The assigned address. |
| * @return This builder. |
| */ |
| public Builder setAssignedV4Address(@Nullable final Inet4Address assignedV4Address) { |
| mAssignedAddress = assignedV4Address; |
| return this; |
| } |
| |
| /** |
| * Set the group hint. |
| * @param groupHint The group hint. |
| * @return This builder. |
| */ |
| public Builder setGroupHint(@Nullable final String groupHint) { |
| mGroupHint = groupHint; |
| return this; |
| } |
| |
| /** |
| * Set the DNS addresses. |
| * @param dnsAddresses The DNS addresses. |
| * @return This builder. |
| */ |
| public Builder setDnsAddresses(@Nullable final List<InetAddress> dnsAddresses) { |
| if (DBG && null != dnsAddresses) { |
| // Parceling code crashes if one of the addresses is null, therefore validate |
| // them when running in debug. |
| for (final InetAddress address : dnsAddresses) { |
| if (null == address) throw new IllegalArgumentException("Null DNS address"); |
| } |
| } |
| this.mDnsAddresses = dnsAddresses; |
| return this; |
| } |
| |
| /** |
| * Set the MTU. |
| * @param mtu The MTU. |
| * @return This builder. |
| */ |
| public Builder setMtu(@Nullable final Integer mtu) { |
| if (null != mtu && mtu < 0) throw new IllegalArgumentException("MTU can't be negative"); |
| mMtu = mtu; |
| return this; |
| } |
| |
| /** |
| * Return the built NetworkAttributes object. |
| * @return The built NetworkAttributes object. |
| */ |
| public NetworkAttributes build() { |
| return new NetworkAttributes(mAssignedAddress, mGroupHint, mDnsAddresses, mMtu); |
| } |
| } |
| |
| /** @hide */ |
| public boolean isEmpty() { |
| return (null == assignedV4Address) && (null == groupHint) |
| && (null == dnsAddresses) && (null == mtu); |
| } |
| |
| @Override |
| public boolean equals(@Nullable final Object o) { |
| if (!(o instanceof NetworkAttributes)) return false; |
| final NetworkAttributes other = (NetworkAttributes) o; |
| return Objects.equals(assignedV4Address, other.assignedV4Address) |
| && Objects.equals(groupHint, other.groupHint) |
| && Objects.equals(dnsAddresses, other.dnsAddresses) |
| && Objects.equals(mtu, other.mtu); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(assignedV4Address, groupHint, dnsAddresses, mtu); |
| } |
| |
| /** Pretty print */ |
| @Override |
| public String toString() { |
| final StringJoiner resultJoiner = new StringJoiner(" ", "{", "}"); |
| final ArrayList<String> nullFields = new ArrayList<>(); |
| |
| if (null != assignedV4Address) { |
| resultJoiner.add("assignedV4Addr :"); |
| resultJoiner.add(assignedV4Address.toString()); |
| } else { |
| nullFields.add("assignedV4Addr"); |
| } |
| |
| if (null != groupHint) { |
| resultJoiner.add("groupHint :"); |
| resultJoiner.add(groupHint); |
| } else { |
| nullFields.add("groupHint"); |
| } |
| |
| if (null != dnsAddresses) { |
| resultJoiner.add("dnsAddr : ["); |
| for (final InetAddress addr : dnsAddresses) { |
| resultJoiner.add(addr.getHostAddress()); |
| } |
| resultJoiner.add("]"); |
| } else { |
| nullFields.add("dnsAddr"); |
| } |
| |
| if (null != mtu) { |
| resultJoiner.add("mtu :"); |
| resultJoiner.add(mtu.toString()); |
| } else { |
| nullFields.add("mtu"); |
| } |
| |
| if (!nullFields.isEmpty()) { |
| resultJoiner.add("; Null fields : ["); |
| for (final String field : nullFields) { |
| resultJoiner.add(field); |
| } |
| resultJoiner.add("]"); |
| } |
| |
| return resultJoiner.toString(); |
| } |
| } |