Thomas Vachuska | 24c849c | 2014-10-27 09:53:05 -0700 | [diff] [blame] | 1 | /* |
Thomas Vachuska | 4f1a60c | 2014-10-28 13:39:07 -0700 | [diff] [blame] | 2 | * Copyright 2014 Open Networking Laboratory |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 3 | * |
Thomas Vachuska | 4f1a60c | 2014-10-28 13:39:07 -0700 | [diff] [blame] | 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 |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 7 | * |
Thomas Vachuska | 4f1a60c | 2014-10-28 13:39:07 -0700 | [diff] [blame] | 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. |
Thomas Vachuska | 24c849c | 2014-10-27 09:53:05 -0700 | [diff] [blame] | 15 | */ |
| 16 | |
| 17 | |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 18 | |
| 19 | package org.onlab.packet; |
| 20 | |
| 21 | import java.io.UnsupportedEncodingException; |
| 22 | import java.nio.ByteBuffer; |
| 23 | import java.util.ArrayList; |
| 24 | import java.util.List; |
| 25 | import java.util.ListIterator; |
| 26 | |
samanwita pal | 3ec8aff | 2015-08-03 18:04:27 -0700 | [diff] [blame] | 27 | import static com.google.common.base.Preconditions.checkArgument; |
| 28 | import static org.onlab.packet.PacketUtils.checkInput; |
Jonathan Hart | 2a65575 | 2015-04-07 16:46:33 -0700 | [diff] [blame] | 29 | |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 30 | /** |
| 31 | * |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 32 | */ |
| 33 | public class DHCP extends BasePacket { |
| 34 | /** |
| 35 | * Dynamic Host Configuration Protocol packet. |
| 36 | * ------------------------------------------ |op (1) | htype(1) | hlen(1) | |
| 37 | * hops(1) | ------------------------------------------ | xid (4) | |
| 38 | * ------------------------------------------ | secs (2) | flags (2) | |
| 39 | * ------------------------------------------ | ciaddr (4) | |
| 40 | * ------------------------------------------ | yiaddr (4) | |
| 41 | * ------------------------------------------ | siaddr (4) | |
| 42 | * ------------------------------------------ | giaddr (4) | |
| 43 | * ------------------------------------------ | chaddr (16) | |
| 44 | * ------------------------------------------ | sname (64) | |
| 45 | * ------------------------------------------ | file (128) | |
| 46 | * ------------------------------------------ | options (312) | |
| 47 | * ------------------------------------------ |
| 48 | * |
| 49 | */ |
| 50 | // Header + magic without options |
| 51 | public static final int MIN_HEADER_LENGTH = 240; |
| 52 | public static final byte OPCODE_REQUEST = 0x1; |
| 53 | public static final byte OPCODE_REPLY = 0x2; |
| 54 | |
| 55 | public static final byte HWTYPE_ETHERNET = 0x1; |
| 56 | |
| 57 | public enum DHCPOptionCode { |
samanwita pal | b300ca8 | 2015-07-16 14:36:05 -0700 | [diff] [blame] | 58 | OptionCode_SubnetMask((byte) 1), OptionCode_RouterAddress((byte) 3), OptionCode_DomainServer((byte) 6), |
| 59 | OptionCode_HostName((byte) 12), OptionCode_DomainName((byte) 15), OptionCode_BroadcastAddress((byte) 28), |
| 60 | OptionCode_RequestedIP((byte) 50), OptionCode_LeaseTime((byte) 51), OptionCode_MessageType((byte) 53), |
| 61 | OptionCode_DHCPServerIp((byte) 54), OptionCode_RequestedParameters((byte) 55), |
| 62 | OptionCode_RenewalTime((byte) 58), OPtionCode_RebindingTime((byte) 59), OptionCode_ClientID((byte) 61), |
| 63 | OptionCode_END((byte) 255); |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 64 | |
| 65 | protected byte value; |
| 66 | |
| 67 | private DHCPOptionCode(final byte value) { |
| 68 | this.value = value; |
| 69 | } |
| 70 | |
| 71 | public byte getValue() { |
| 72 | return this.value; |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | protected byte opCode; |
| 77 | protected byte hardwareType; |
| 78 | protected byte hardwareAddressLength; |
| 79 | protected byte hops; |
| 80 | protected int transactionId; |
| 81 | protected short seconds; |
| 82 | protected short flags; |
| 83 | protected int clientIPAddress; |
| 84 | protected int yourIPAddress; |
| 85 | protected int serverIPAddress; |
| 86 | protected int gatewayIPAddress; |
| 87 | protected byte[] clientHardwareAddress; |
| 88 | protected String serverName; |
| 89 | protected String bootFileName; |
| 90 | protected List<DHCPOption> options = new ArrayList<DHCPOption>(); |
| 91 | |
| 92 | /** |
| 93 | * @return the opCode |
| 94 | */ |
| 95 | public byte getOpCode() { |
| 96 | return this.opCode; |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * @param opCode |
| 101 | * the opCode to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 102 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 103 | */ |
| 104 | public DHCP setOpCode(final byte opCode) { |
| 105 | this.opCode = opCode; |
| 106 | return this; |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * @return the hardwareType |
| 111 | */ |
| 112 | public byte getHardwareType() { |
| 113 | return this.hardwareType; |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * @param hardwareType |
| 118 | * the hardwareType to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 119 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 120 | */ |
| 121 | public DHCP setHardwareType(final byte hardwareType) { |
| 122 | this.hardwareType = hardwareType; |
| 123 | return this; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * @return the hardwareAddressLength |
| 128 | */ |
| 129 | public byte getHardwareAddressLength() { |
| 130 | return this.hardwareAddressLength; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * @param hardwareAddressLength |
| 135 | * the hardwareAddressLength to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 136 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 137 | */ |
| 138 | public DHCP setHardwareAddressLength(final byte hardwareAddressLength) { |
| 139 | this.hardwareAddressLength = hardwareAddressLength; |
| 140 | return this; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * @return the hops |
| 145 | */ |
| 146 | public byte getHops() { |
| 147 | return this.hops; |
| 148 | } |
| 149 | |
| 150 | /** |
| 151 | * @param hops |
| 152 | * the hops to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 153 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 154 | */ |
| 155 | public DHCP setHops(final byte hops) { |
| 156 | this.hops = hops; |
| 157 | return this; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * @return the transactionId |
| 162 | */ |
| 163 | public int getTransactionId() { |
| 164 | return this.transactionId; |
| 165 | } |
| 166 | |
| 167 | /** |
| 168 | * @param transactionId |
| 169 | * the transactionId to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 170 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 171 | */ |
| 172 | public DHCP setTransactionId(final int transactionId) { |
| 173 | this.transactionId = transactionId; |
| 174 | return this; |
| 175 | } |
| 176 | |
| 177 | /** |
| 178 | * @return the seconds |
| 179 | */ |
| 180 | public short getSeconds() { |
| 181 | return this.seconds; |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * @param seconds |
| 186 | * the seconds to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 187 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 188 | */ |
| 189 | public DHCP setSeconds(final short seconds) { |
| 190 | this.seconds = seconds; |
| 191 | return this; |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * @return the flags |
| 196 | */ |
| 197 | public short getFlags() { |
| 198 | return this.flags; |
| 199 | } |
| 200 | |
| 201 | /** |
| 202 | * @param flags |
| 203 | * the flags to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 204 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 205 | */ |
| 206 | public DHCP setFlags(final short flags) { |
| 207 | this.flags = flags; |
| 208 | return this; |
| 209 | } |
| 210 | |
| 211 | /** |
| 212 | * @return the clientIPAddress |
| 213 | */ |
| 214 | public int getClientIPAddress() { |
| 215 | return this.clientIPAddress; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * @param clientIPAddress |
| 220 | * the clientIPAddress to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 221 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 222 | */ |
| 223 | public DHCP setClientIPAddress(final int clientIPAddress) { |
| 224 | this.clientIPAddress = clientIPAddress; |
| 225 | return this; |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * @return the yourIPAddress |
| 230 | */ |
| 231 | public int getYourIPAddress() { |
| 232 | return this.yourIPAddress; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * @param yourIPAddress |
| 237 | * the yourIPAddress to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 238 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 239 | */ |
| 240 | public DHCP setYourIPAddress(final int yourIPAddress) { |
| 241 | this.yourIPAddress = yourIPAddress; |
| 242 | return this; |
| 243 | } |
| 244 | |
| 245 | /** |
| 246 | * @return the serverIPAddress |
| 247 | */ |
| 248 | public int getServerIPAddress() { |
| 249 | return this.serverIPAddress; |
| 250 | } |
| 251 | |
| 252 | /** |
| 253 | * @param serverIPAddress |
| 254 | * the serverIPAddress to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 255 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 256 | */ |
| 257 | public DHCP setServerIPAddress(final int serverIPAddress) { |
| 258 | this.serverIPAddress = serverIPAddress; |
| 259 | return this; |
| 260 | } |
| 261 | |
| 262 | /** |
| 263 | * @return the gatewayIPAddress |
| 264 | */ |
| 265 | public int getGatewayIPAddress() { |
| 266 | return this.gatewayIPAddress; |
| 267 | } |
| 268 | |
| 269 | /** |
| 270 | * @param gatewayIPAddress |
| 271 | * the gatewayIPAddress to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 272 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 273 | */ |
| 274 | public DHCP setGatewayIPAddress(final int gatewayIPAddress) { |
| 275 | this.gatewayIPAddress = gatewayIPAddress; |
| 276 | return this; |
| 277 | } |
| 278 | |
| 279 | /** |
| 280 | * @return the clientHardwareAddress |
| 281 | */ |
| 282 | public byte[] getClientHardwareAddress() { |
| 283 | return this.clientHardwareAddress; |
| 284 | } |
| 285 | |
| 286 | /** |
| 287 | * @param clientHardwareAddress |
| 288 | * the clientHardwareAddress to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 289 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 290 | */ |
| 291 | public DHCP setClientHardwareAddress(final byte[] clientHardwareAddress) { |
| 292 | this.clientHardwareAddress = clientHardwareAddress; |
| 293 | return this; |
| 294 | } |
| 295 | |
| 296 | /** |
| 297 | * Gets a specific DHCP option parameter. |
| 298 | * |
tom | 5f18cf3 | 2014-09-13 14:10:57 -0700 | [diff] [blame] | 299 | * @param optionCode |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 300 | * The option code to get |
| 301 | * @return The value of the option if it exists, null otherwise |
| 302 | */ |
| 303 | public DHCPOption getOption(final DHCPOptionCode optionCode) { |
| 304 | for (final DHCPOption opt : this.options) { |
| 305 | if (opt.code == optionCode.value) { |
| 306 | return opt; |
| 307 | } |
| 308 | } |
| 309 | return null; |
| 310 | } |
| 311 | |
| 312 | /** |
| 313 | * @return the options |
| 314 | */ |
| 315 | public List<DHCPOption> getOptions() { |
| 316 | return this.options; |
| 317 | } |
| 318 | |
| 319 | /** |
| 320 | * @param options |
| 321 | * the options to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 322 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 323 | */ |
| 324 | public DHCP setOptions(final List<DHCPOption> options) { |
| 325 | this.options = options; |
| 326 | return this; |
| 327 | } |
| 328 | |
| 329 | /** |
| 330 | * @return the packetType base on option 53 |
| 331 | */ |
| 332 | public DHCPPacketType getPacketType() { |
| 333 | final ListIterator<DHCPOption> lit = this.options.listIterator(); |
| 334 | while (lit.hasNext()) { |
| 335 | final DHCPOption option = lit.next(); |
| 336 | // only care option 53 |
| 337 | if (option.getCode() == 53) { |
| 338 | return DHCPPacketType.getType(option.getData()[0]); |
| 339 | } |
| 340 | } |
| 341 | return null; |
| 342 | } |
| 343 | |
| 344 | /** |
| 345 | * @return the serverName |
| 346 | */ |
| 347 | public String getServerName() { |
| 348 | return this.serverName; |
| 349 | } |
| 350 | |
| 351 | /** |
| 352 | * @param server |
| 353 | * the serverName to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 354 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 355 | */ |
| 356 | public DHCP setServerName(final String server) { |
| 357 | this.serverName = server; |
| 358 | return this; |
| 359 | } |
| 360 | |
| 361 | /** |
| 362 | * @return the bootFileName |
| 363 | */ |
| 364 | public String getBootFileName() { |
| 365 | return this.bootFileName; |
| 366 | } |
| 367 | |
| 368 | /** |
| 369 | * @param bootFile |
| 370 | * the bootFileName to set |
Yuta HIGUCHI | 2281b3f | 2014-11-04 00:20:48 -0800 | [diff] [blame] | 371 | * @return this |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 372 | */ |
| 373 | public DHCP setBootFileName(final String bootFile) { |
| 374 | this.bootFileName = bootFile; |
| 375 | return this; |
| 376 | } |
| 377 | |
| 378 | @Override |
| 379 | public byte[] serialize() { |
| 380 | // not guaranteed to retain length/exact format |
| 381 | this.resetChecksum(); |
| 382 | |
| 383 | // minimum size 240 including magic cookie, options generally padded to |
| 384 | // 300 |
| 385 | int optionsLength = 0; |
| 386 | for (final DHCPOption option : this.options) { |
Yuta HIGUCHI | e5ca93b | 2014-10-23 09:49:00 -0700 | [diff] [blame] | 387 | if (option.getCode() == 0 || option.getCode() == ((byte) 255)) { |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 388 | optionsLength += 1; |
| 389 | } else { |
| 390 | optionsLength += 2 + (0xff & option.getLength()); |
| 391 | } |
| 392 | } |
| 393 | int optionsPadLength = 0; |
| 394 | if (optionsLength < 60) { |
| 395 | optionsPadLength = 60 - optionsLength; |
| 396 | } |
| 397 | |
| 398 | final byte[] data = new byte[240 + optionsLength + optionsPadLength]; |
| 399 | final ByteBuffer bb = ByteBuffer.wrap(data); |
| 400 | bb.put(this.opCode); |
| 401 | bb.put(this.hardwareType); |
| 402 | bb.put(this.hardwareAddressLength); |
| 403 | bb.put(this.hops); |
| 404 | bb.putInt(this.transactionId); |
| 405 | bb.putShort(this.seconds); |
| 406 | bb.putShort(this.flags); |
| 407 | bb.putInt(this.clientIPAddress); |
| 408 | bb.putInt(this.yourIPAddress); |
| 409 | bb.putInt(this.serverIPAddress); |
| 410 | bb.putInt(this.gatewayIPAddress); |
samanwita pal | 3ec8aff | 2015-08-03 18:04:27 -0700 | [diff] [blame] | 411 | checkArgument(this.clientHardwareAddress.length <= 16, |
| 412 | "Hardware address is too long (%s bytes)", this.clientHardwareAddress.length); |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 413 | bb.put(this.clientHardwareAddress); |
| 414 | if (this.clientHardwareAddress.length < 16) { |
| 415 | for (int i = 0; i < 16 - this.clientHardwareAddress.length; ++i) { |
| 416 | bb.put((byte) 0x0); |
| 417 | } |
| 418 | } |
| 419 | this.writeString(this.serverName, bb, 64); |
| 420 | this.writeString(this.bootFileName, bb, 128); |
| 421 | // magic cookie |
| 422 | bb.put((byte) 0x63); |
| 423 | bb.put((byte) 0x82); |
| 424 | bb.put((byte) 0x53); |
| 425 | bb.put((byte) 0x63); |
| 426 | for (final DHCPOption option : this.options) { |
| 427 | final int code = option.getCode() & 0xff; |
| 428 | bb.put((byte) code); |
| 429 | if (code != 0 && code != 255) { |
| 430 | bb.put(option.getLength()); |
| 431 | bb.put(option.getData()); |
| 432 | } |
| 433 | } |
| 434 | // assume the rest is padded out with zeroes |
| 435 | return data; |
| 436 | } |
| 437 | |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 438 | @Override |
| 439 | public IPacket deserialize(final byte[] data, final int offset, |
Jonathan Hart | 2a65575 | 2015-04-07 16:46:33 -0700 | [diff] [blame] | 440 | final int length) { |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 441 | final ByteBuffer bb = ByteBuffer.wrap(data, offset, length); |
| 442 | if (bb.remaining() < DHCP.MIN_HEADER_LENGTH) { |
| 443 | return this; |
| 444 | } |
| 445 | |
| 446 | this.opCode = bb.get(); |
| 447 | this.hardwareType = bb.get(); |
| 448 | this.hardwareAddressLength = bb.get(); |
| 449 | this.hops = bb.get(); |
| 450 | this.transactionId = bb.getInt(); |
| 451 | this.seconds = bb.getShort(); |
| 452 | this.flags = bb.getShort(); |
| 453 | this.clientIPAddress = bb.getInt(); |
| 454 | this.yourIPAddress = bb.getInt(); |
| 455 | this.serverIPAddress = bb.getInt(); |
| 456 | this.gatewayIPAddress = bb.getInt(); |
| 457 | final int hardwareAddressLength = 0xff & this.hardwareAddressLength; |
| 458 | this.clientHardwareAddress = new byte[hardwareAddressLength]; |
| 459 | |
| 460 | bb.get(this.clientHardwareAddress); |
| 461 | for (int i = hardwareAddressLength; i < 16; ++i) { |
| 462 | bb.get(); |
| 463 | } |
| 464 | this.serverName = this.readString(bb, 64); |
| 465 | this.bootFileName = this.readString(bb, 128); |
| 466 | // read the magic cookie |
| 467 | // magic cookie |
| 468 | bb.get(); |
| 469 | bb.get(); |
| 470 | bb.get(); |
| 471 | bb.get(); |
| 472 | // read options |
| 473 | while (bb.hasRemaining()) { |
| 474 | final DHCPOption option = new DHCPOption(); |
| 475 | int code = 0xff & bb.get(); // convert signed byte to int in range |
| 476 | // [0,255] |
| 477 | option.setCode((byte) code); |
| 478 | if (code == 0) { |
| 479 | // skip these |
| 480 | continue; |
| 481 | } else if (code != 255) { |
| 482 | if (bb.hasRemaining()) { |
| 483 | final int l = 0xff & bb.get(); // convert signed byte to |
| 484 | // int in range [0,255] |
| 485 | option.setLength((byte) l); |
| 486 | if (bb.remaining() >= l) { |
| 487 | final byte[] optionData = new byte[l]; |
| 488 | bb.get(optionData); |
| 489 | option.setData(optionData); |
| 490 | } else { |
| 491 | // Skip the invalid option and set the END option |
| 492 | code = 0xff; |
| 493 | option.setCode((byte) code); |
| 494 | option.setLength((byte) 0); |
| 495 | } |
| 496 | } else { |
| 497 | // Skip the invalid option and set the END option |
| 498 | code = 0xff; |
| 499 | option.setCode((byte) code); |
| 500 | option.setLength((byte) 0); |
| 501 | } |
| 502 | } |
| 503 | this.options.add(option); |
| 504 | if (code == 255) { |
| 505 | // remaining bytes are supposed to be 0, but ignore them just in |
| 506 | // case |
| 507 | break; |
| 508 | } |
| 509 | } |
| 510 | |
| 511 | return this; |
| 512 | } |
| 513 | |
Jonathan Hart | 2a65575 | 2015-04-07 16:46:33 -0700 | [diff] [blame] | 514 | protected void writeString(final String string, final ByteBuffer bb, |
| 515 | final int maxLength) { |
| 516 | if (string == null) { |
| 517 | for (int i = 0; i < maxLength; ++i) { |
| 518 | bb.put((byte) 0x0); |
| 519 | } |
| 520 | } else { |
| 521 | byte[] bytes = null; |
| 522 | try { |
| 523 | bytes = string.getBytes("ascii"); |
| 524 | } catch (final UnsupportedEncodingException e) { |
| 525 | throw new RuntimeException("Failure encoding server name", e); |
| 526 | } |
| 527 | int writeLength = bytes.length; |
| 528 | if (writeLength > maxLength) { |
| 529 | writeLength = maxLength; |
| 530 | } |
| 531 | bb.put(bytes, 0, writeLength); |
| 532 | for (int i = writeLength; i < maxLength; ++i) { |
| 533 | bb.put((byte) 0x0); |
| 534 | } |
| 535 | } |
| 536 | } |
| 537 | |
| 538 | private static String readString(final ByteBuffer bb, final int maxLength) { |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 539 | final byte[] bytes = new byte[maxLength]; |
| 540 | bb.get(bytes); |
| 541 | String result = null; |
| 542 | try { |
| 543 | result = new String(bytes, "ascii").trim(); |
| 544 | } catch (final UnsupportedEncodingException e) { |
| 545 | throw new RuntimeException("Failure decoding string", e); |
| 546 | } |
| 547 | return result; |
| 548 | } |
Jonathan Hart | 2a65575 | 2015-04-07 16:46:33 -0700 | [diff] [blame] | 549 | |
| 550 | /** |
| 551 | * Deserializer function for DHCP packets. |
| 552 | * |
| 553 | * @return deserializer function |
| 554 | */ |
| 555 | public static Deserializer<DHCP> deserializer() { |
| 556 | return (data, offset, length) -> { |
| 557 | checkInput(data, offset, length, MIN_HEADER_LENGTH); |
| 558 | |
| 559 | ByteBuffer bb = ByteBuffer.wrap(data, offset, length); |
| 560 | DHCP dhcp = new DHCP(); |
| 561 | |
| 562 | dhcp.opCode = bb.get(); |
| 563 | dhcp.hardwareType = bb.get(); |
| 564 | dhcp.hardwareAddressLength = bb.get(); |
| 565 | dhcp.hops = bb.get(); |
| 566 | dhcp.transactionId = bb.getInt(); |
| 567 | dhcp.seconds = bb.getShort(); |
| 568 | dhcp.flags = bb.getShort(); |
| 569 | dhcp.clientIPAddress = bb.getInt(); |
| 570 | dhcp.yourIPAddress = bb.getInt(); |
| 571 | dhcp.serverIPAddress = bb.getInt(); |
| 572 | dhcp.gatewayIPAddress = bb.getInt(); |
| 573 | final int hardwareAddressLength = 0xff & dhcp.hardwareAddressLength; |
| 574 | dhcp.clientHardwareAddress = new byte[hardwareAddressLength]; |
| 575 | |
| 576 | bb.get(dhcp.clientHardwareAddress); |
| 577 | for (int i = hardwareAddressLength; i < 16; ++i) { |
| 578 | bb.get(); |
| 579 | } |
| 580 | dhcp.serverName = readString(bb, 64); |
| 581 | dhcp.bootFileName = readString(bb, 128); |
| 582 | // read the magic cookie |
| 583 | // magic cookie |
| 584 | bb.get(); |
| 585 | bb.get(); |
| 586 | bb.get(); |
| 587 | bb.get(); |
| 588 | |
| 589 | // read options |
| 590 | boolean foundEndOptionsMarker = false; |
| 591 | while (bb.hasRemaining()) { |
| 592 | final DHCPOption option = new DHCPOption(); |
| 593 | int code = 0xff & bb.get(); // convert signed byte to int in range |
| 594 | // [0,255] |
| 595 | option.setCode((byte) code); |
| 596 | if (code == 0) { |
| 597 | // skip these |
| 598 | continue; |
| 599 | } else if (code != 255) { |
| 600 | if (bb.hasRemaining()) { |
| 601 | final int l = 0xff & bb.get(); // convert signed byte to |
| 602 | // int in range [0,255] |
| 603 | option.setLength((byte) l); |
| 604 | if (bb.remaining() >= l) { |
| 605 | final byte[] optionData = new byte[l]; |
| 606 | bb.get(optionData); |
| 607 | option.setData(optionData); |
| 608 | dhcp.options.add(option); |
| 609 | } else { |
| 610 | throw new DeserializationException( |
| 611 | "Buffer underflow while reading DHCP option"); |
| 612 | } |
| 613 | } |
| 614 | } else if (code == 255) { |
alshabib | 0588e57 | 2015-09-04 12:00:42 -0700 | [diff] [blame] | 615 | DHCPOption end = new DHCPOption(); |
| 616 | end.setCode((byte) 255); |
| 617 | dhcp.options.add(end); |
Jonathan Hart | 2a65575 | 2015-04-07 16:46:33 -0700 | [diff] [blame] | 618 | // remaining bytes are supposed to be 0, but ignore them just in |
| 619 | // case |
| 620 | foundEndOptionsMarker = true; |
| 621 | break; |
| 622 | } |
| 623 | } |
| 624 | |
| 625 | if (!foundEndOptionsMarker) { |
| 626 | throw new DeserializationException("DHCP End options marker was missing"); |
| 627 | } |
| 628 | |
| 629 | return dhcp; |
| 630 | }; |
| 631 | } |
alshabib | c4901cd | 2014-09-05 16:50:40 -0700 | [diff] [blame] | 632 | } |