Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.net.ipmemorystore; |
| 18 | |
| 19 | import android.annotation.NonNull; |
| 20 | import android.annotation.Nullable; |
| 21 | |
| 22 | import com.android.internal.annotations.VisibleForTesting; |
| 23 | |
| 24 | import java.net.Inet4Address; |
| 25 | import java.net.InetAddress; |
| 26 | import java.net.UnknownHostException; |
| 27 | import java.util.ArrayList; |
| 28 | import java.util.Collections; |
| 29 | import java.util.List; |
| 30 | import java.util.Objects; |
Chalard Jean | 8fe503f | 2018-12-14 00:59:53 +0900 | [diff] [blame] | 31 | import java.util.StringJoiner; |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 32 | |
| 33 | /** |
| 34 | * A POD object to represent attributes of a single L2 network entry. |
| 35 | * @hide |
| 36 | */ |
| 37 | public class NetworkAttributes { |
| 38 | private static final boolean DBG = true; |
| 39 | |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 40 | // Weight cutoff for grouping. To group, a similarity score is computed with the following |
| 41 | // algorithm : if both fields are non-null and equals() then add their assigned weight, else if |
| 42 | // both are null then add a portion of their assigned weight (see NULL_MATCH_WEIGHT), |
| 43 | // otherwise add nothing. |
| 44 | // As a guideline, this should be something like 60~75% of the total weights in this class. The |
| 45 | // design states "in essence a reader should imagine that if two important columns don't match, |
| 46 | // or one important and several unimportant columns don't match then the two records are |
| 47 | // considered a different group". |
| 48 | private static final float TOTAL_WEIGHT_CUTOFF = 520.0f; |
| 49 | // The portion of the weight that is earned when scoring group-sameness by having both columns |
| 50 | // being null. This is because some networks rightfully don't have some attributes (e.g. a |
| 51 | // V6-only network won't have an assigned V4 address) and both being null should count for |
| 52 | // something, but attributes may also be null just because data is unavailable. |
| 53 | private static final float NULL_MATCH_WEIGHT = 0.25f; |
| 54 | |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 55 | // The v4 address that was assigned to this device the last time it joined this network. |
| 56 | // This typically comes from DHCP but could be something else like static configuration. |
| 57 | // This does not apply to IPv6. |
| 58 | // TODO : add a list of v6 prefixes for the v6 case. |
| 59 | @Nullable |
| 60 | public final Inet4Address assignedV4Address; |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 61 | private static final float WEIGHT_ASSIGNEDV4ADDR = 300.0f; |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 62 | |
| 63 | // Optionally supplied by the client if it has an opinion on L3 network. For example, this |
| 64 | // could be a hash of the SSID + security type on WiFi. |
| 65 | @Nullable |
| 66 | public final String groupHint; |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 67 | private static final float WEIGHT_GROUPHINT = 300.0f; |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 68 | |
| 69 | // The list of DNS server addresses. |
| 70 | @Nullable |
| 71 | public final List<InetAddress> dnsAddresses; |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 72 | private static final float WEIGHT_DNSADDRESSES = 200.0f; |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 73 | |
| 74 | // The mtu on this network. |
| 75 | @Nullable |
| 76 | public final Integer mtu; |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 77 | private static final float WEIGHT_MTU = 50.0f; |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 78 | |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 79 | // The sum of all weights in this class. Tests ensure that this stays equal to the total of |
| 80 | // all weights. |
| 81 | /** @hide */ |
| 82 | @VisibleForTesting |
| 83 | public static final float TOTAL_WEIGHT = WEIGHT_ASSIGNEDV4ADDR |
| 84 | + WEIGHT_GROUPHINT |
| 85 | + WEIGHT_DNSADDRESSES |
| 86 | + WEIGHT_MTU; |
| 87 | |
| 88 | /** @hide */ |
| 89 | @VisibleForTesting |
| 90 | public NetworkAttributes( |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 91 | @Nullable final Inet4Address assignedV4Address, |
| 92 | @Nullable final String groupHint, |
| 93 | @Nullable final List<InetAddress> dnsAddresses, |
| 94 | @Nullable final Integer mtu) { |
| 95 | if (mtu != null && mtu < 0) throw new IllegalArgumentException("MTU can't be negative"); |
| 96 | this.assignedV4Address = assignedV4Address; |
| 97 | this.groupHint = groupHint; |
| 98 | this.dnsAddresses = null == dnsAddresses ? null : |
| 99 | Collections.unmodifiableList(new ArrayList<>(dnsAddresses)); |
| 100 | this.mtu = mtu; |
| 101 | } |
| 102 | |
| 103 | @VisibleForTesting |
| 104 | public NetworkAttributes(@NonNull final NetworkAttributesParcelable parcelable) { |
| 105 | // The call to the other constructor must be the first statement of this constructor, |
| 106 | // so everything has to be inline |
| 107 | this((Inet4Address) getByAddressOrNull(parcelable.assignedV4Address), |
| 108 | parcelable.groupHint, |
| 109 | blobArrayToInetAddressList(parcelable.dnsAddresses), |
| 110 | parcelable.mtu >= 0 ? parcelable.mtu : null); |
| 111 | } |
| 112 | |
| 113 | @Nullable |
| 114 | private static InetAddress getByAddressOrNull(@Nullable final byte[] address) { |
| 115 | try { |
| 116 | return InetAddress.getByAddress(address); |
| 117 | } catch (UnknownHostException e) { |
| 118 | return null; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | @Nullable |
| 123 | private static List<InetAddress> blobArrayToInetAddressList(@Nullable final Blob[] blobs) { |
| 124 | if (null == blobs) return null; |
| 125 | final ArrayList<InetAddress> list = new ArrayList<>(blobs.length); |
| 126 | for (final Blob b : blobs) { |
| 127 | final InetAddress addr = getByAddressOrNull(b.data); |
| 128 | if (null != addr) list.add(addr); |
| 129 | } |
| 130 | return list; |
| 131 | } |
| 132 | |
| 133 | @Nullable |
| 134 | private static Blob[] inetAddressListToBlobArray(@Nullable final List<InetAddress> addresses) { |
| 135 | if (null == addresses) return null; |
| 136 | final ArrayList<Blob> blobs = new ArrayList<>(); |
| 137 | for (int i = 0; i < addresses.size(); ++i) { |
| 138 | final InetAddress addr = addresses.get(i); |
| 139 | if (null == addr) continue; |
| 140 | final Blob b = new Blob(); |
| 141 | b.data = addr.getAddress(); |
| 142 | blobs.add(b); |
| 143 | } |
| 144 | return blobs.toArray(new Blob[0]); |
| 145 | } |
| 146 | |
| 147 | /** Converts this NetworkAttributes to a parcelable object */ |
| 148 | @NonNull |
| 149 | public NetworkAttributesParcelable toParcelable() { |
| 150 | final NetworkAttributesParcelable parcelable = new NetworkAttributesParcelable(); |
| 151 | parcelable.assignedV4Address = |
| 152 | (null == assignedV4Address) ? null : assignedV4Address.getAddress(); |
| 153 | parcelable.groupHint = groupHint; |
| 154 | parcelable.dnsAddresses = inetAddressListToBlobArray(dnsAddresses); |
| 155 | parcelable.mtu = (null == mtu) ? -1 : mtu; |
| 156 | return parcelable; |
| 157 | } |
| 158 | |
Chalard Jean | a39756a | 2019-01-16 18:18:44 +0900 | [diff] [blame^] | 159 | private float samenessContribution(final float weight, |
| 160 | @Nullable final Object o1, @Nullable final Object o2) { |
| 161 | if (null == o1) { |
| 162 | return (null == o2) ? weight * NULL_MATCH_WEIGHT : 0f; |
| 163 | } |
| 164 | return Objects.equals(o1, o2) ? weight : 0f; |
| 165 | } |
| 166 | |
| 167 | /** @hide */ |
| 168 | public float getNetworkGroupSamenessConfidence(@NonNull final NetworkAttributes o) { |
| 169 | final float samenessScore = |
| 170 | samenessContribution(WEIGHT_ASSIGNEDV4ADDR, assignedV4Address, o.assignedV4Address) |
| 171 | + samenessContribution(WEIGHT_GROUPHINT, groupHint, o.groupHint) |
| 172 | + samenessContribution(WEIGHT_DNSADDRESSES, dnsAddresses, o.dnsAddresses) |
| 173 | + samenessContribution(WEIGHT_MTU, mtu, o.mtu); |
| 174 | // The minimum is 0, the max is TOTAL_WEIGHT and should be represented by 1.0, and |
| 175 | // TOTAL_WEIGHT_CUTOFF should represent 0.5, but there is no requirement that |
| 176 | // TOTAL_WEIGHT_CUTOFF would be half of TOTAL_WEIGHT (indeed, it should not be). |
| 177 | // So scale scores under the cutoff between 0 and 0.5, and the scores over the cutoff |
| 178 | // between 0.5 and 1.0. |
| 179 | if (samenessScore < TOTAL_WEIGHT_CUTOFF) { |
| 180 | return samenessScore / (TOTAL_WEIGHT_CUTOFF * 2); |
| 181 | } else { |
| 182 | return (samenessScore - TOTAL_WEIGHT_CUTOFF) / (TOTAL_WEIGHT - TOTAL_WEIGHT_CUTOFF) / 2 |
| 183 | + 0.5f; |
| 184 | } |
| 185 | } |
| 186 | |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 187 | /** @hide */ |
| 188 | public static class Builder { |
| 189 | @Nullable |
| 190 | private Inet4Address mAssignedAddress; |
| 191 | @Nullable |
| 192 | private String mGroupHint; |
| 193 | @Nullable |
| 194 | private List<InetAddress> mDnsAddresses; |
| 195 | @Nullable |
| 196 | private Integer mMtu; |
| 197 | |
| 198 | /** |
| 199 | * Set the assigned address. |
| 200 | * @param assignedV4Address The assigned address. |
| 201 | * @return This builder. |
| 202 | */ |
| 203 | public Builder setAssignedV4Address(@Nullable final Inet4Address assignedV4Address) { |
| 204 | mAssignedAddress = assignedV4Address; |
| 205 | return this; |
| 206 | } |
| 207 | |
| 208 | /** |
| 209 | * Set the group hint. |
| 210 | * @param groupHint The group hint. |
| 211 | * @return This builder. |
| 212 | */ |
| 213 | public Builder setGroupHint(@Nullable final String groupHint) { |
| 214 | mGroupHint = groupHint; |
| 215 | return this; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * Set the DNS addresses. |
| 220 | * @param dnsAddresses The DNS addresses. |
| 221 | * @return This builder. |
| 222 | */ |
| 223 | public Builder setDnsAddresses(@Nullable final List<InetAddress> dnsAddresses) { |
| 224 | if (DBG && null != dnsAddresses) { |
| 225 | // Parceling code crashes if one of the addresses is null, therefore validate |
| 226 | // them when running in debug. |
| 227 | for (final InetAddress address : dnsAddresses) { |
| 228 | if (null == address) throw new IllegalArgumentException("Null DNS address"); |
| 229 | } |
| 230 | } |
| 231 | this.mDnsAddresses = dnsAddresses; |
| 232 | return this; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * Set the MTU. |
| 237 | * @param mtu The MTU. |
| 238 | * @return This builder. |
| 239 | */ |
| 240 | public Builder setMtu(@Nullable final Integer mtu) { |
| 241 | if (null != mtu && mtu < 0) throw new IllegalArgumentException("MTU can't be negative"); |
| 242 | mMtu = mtu; |
| 243 | return this; |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * Return the built NetworkAttributes object. |
| 248 | * @return The built NetworkAttributes object. |
| 249 | */ |
| 250 | public NetworkAttributes build() { |
| 251 | return new NetworkAttributes(mAssignedAddress, mGroupHint, mDnsAddresses, mMtu); |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | @Override |
| 256 | public boolean equals(@Nullable final Object o) { |
| 257 | if (!(o instanceof NetworkAttributes)) return false; |
| 258 | final NetworkAttributes other = (NetworkAttributes) o; |
| 259 | return Objects.equals(assignedV4Address, other.assignedV4Address) |
| 260 | && Objects.equals(groupHint, other.groupHint) |
| 261 | && Objects.equals(dnsAddresses, other.dnsAddresses) |
| 262 | && Objects.equals(mtu, other.mtu); |
| 263 | } |
| 264 | |
| 265 | @Override |
| 266 | public int hashCode() { |
| 267 | return Objects.hash(assignedV4Address, groupHint, dnsAddresses, mtu); |
| 268 | } |
Chalard Jean | 8fe503f | 2018-12-14 00:59:53 +0900 | [diff] [blame] | 269 | |
| 270 | /** Pretty print */ |
| 271 | @Override |
| 272 | public String toString() { |
| 273 | final StringJoiner resultJoiner = new StringJoiner(" ", "{", "}"); |
| 274 | final ArrayList<String> nullFields = new ArrayList<>(); |
| 275 | |
| 276 | if (null != assignedV4Address) { |
| 277 | resultJoiner.add("assignedV4Addr :"); |
| 278 | resultJoiner.add(assignedV4Address.toString()); |
| 279 | } else { |
| 280 | nullFields.add("assignedV4Addr"); |
| 281 | } |
| 282 | |
| 283 | if (null != groupHint) { |
| 284 | resultJoiner.add("groupHint :"); |
| 285 | resultJoiner.add(groupHint); |
| 286 | } else { |
| 287 | nullFields.add("groupHint"); |
| 288 | } |
| 289 | |
| 290 | if (null != dnsAddresses) { |
| 291 | resultJoiner.add("dnsAddr : ["); |
| 292 | for (final InetAddress addr : dnsAddresses) { |
| 293 | resultJoiner.add(addr.getHostAddress()); |
| 294 | } |
| 295 | resultJoiner.add("]"); |
| 296 | } else { |
| 297 | nullFields.add("dnsAddr"); |
| 298 | } |
| 299 | |
| 300 | if (null != mtu) { |
| 301 | resultJoiner.add("mtu :"); |
| 302 | resultJoiner.add(mtu.toString()); |
| 303 | } else { |
| 304 | nullFields.add("mtu"); |
| 305 | } |
| 306 | |
| 307 | if (!nullFields.isEmpty()) { |
| 308 | resultJoiner.add("; Null fields : ["); |
| 309 | for (final String field : nullFields) { |
| 310 | resultJoiner.add(field); |
| 311 | } |
| 312 | resultJoiner.add("]"); |
| 313 | } |
| 314 | |
| 315 | return resultJoiner.toString(); |
| 316 | } |
Chalard Jean | f89d7be | 2018-12-07 23:09:02 +0900 | [diff] [blame] | 317 | } |