dhcp4_srv.cc 74.9 KB
Newer Older
1
// Copyright (C) 2011-2014 Internet Systems Consortium, Inc. ("ISC")
2 3 4 5 6 7 8 9 10 11 12 13 14
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

15
#include <asiolink/io_address.h>
16
#include <dhcp/dhcp4.h>
17 18
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
19
#include <dhcp/iface_mgr.h>
20
#include <dhcp/option4_addrlst.h>
21
#include <dhcp/option_int.h>
22
#include <dhcp/option_int_array.h>
23
#include <dhcp/option_vendor.h>
24
#include <dhcp/option_string.h>
25
#include <dhcp/pkt4.h>
26
#include <dhcp/docsis3_option_defs.h>
27 28
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
29 30
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
31 32 33 34 35
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
#include <dhcpsrv/subnet.h>
#include <dhcpsrv/utils.h>
36
#include <dhcpsrv/utils.h>
37
#include <hooks/callout_handle.h>
38
#include <hooks/hooks_manager.h>
39
#include <util/strutil.h>
40

41
#include <boost/bind.hpp>
42
#include <boost/foreach.hpp>
43 44 45

#include <iomanip>

46 47
using namespace isc;
using namespace isc::asiolink;
48
using namespace isc::dhcp;
49
using namespace isc::dhcp_ddns;
50
using namespace isc::hooks;
51 52
using namespace isc::log;
using namespace std;
53

54
/// Structure that holds registered hook indexes
55 56
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
57 58
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
59
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
60
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
61
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
62

63 64 65
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
66 67 68
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
69 70
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
71 72 73 74 75 76 77
    }
};

// Declare a Hooks object. As this is outside any function or method, it
// will be instantiated (and the constructor run) when the module is loaded.
// As a result, the hook indexes will be defined before any method in this
// module is called.
78
Dhcp4Hooks Hooks;
79

80 81 82
namespace isc {
namespace dhcp {

83 84
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

85
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const char* dbconfig, const bool use_bcast,
86
                     const bool direct_response_desired)
87
: shutdown_(true), alloc_engine_(), port_(port),
88
    use_bcast_(use_bcast), hook_index_pkt4_receive_(-1),
89 90
    hook_index_subnet4_select_(-1), hook_index_pkt4_send_(-1) {

91
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
92
    try {
93 94 95 96
        // Open sockets only if port is non-zero. Port 0 is used for testing
        // purposes in two cases:
        // - when non-socket related testing is performed
        // - when the particular test supplies its own packet filtering class.
97
        if (port) {
98 99 100 101 102 103 104 105 106
            // First call to instance() will create IfaceMgr (it's a singleton)
            // it may throw something if things go wrong.
            // The 'true' value of the call to setMatchingPacketFilter imposes
            // that IfaceMgr will try to use the mechanism to respond directly
            // to the client which doesn't have address assigned. This capability
            // may be lacking on some OSes, so there is no guarantee that server
            // will be able to respond directly.
            IfaceMgr::instance().setMatchingPacketFilter(direct_response_desired);

107 108 109 110 111 112
            // Create error handler. This handler will be called every time
            // the socket opening operation fails. We use this handler to
            // log a warning.
            isc::dhcp::IfaceMgrErrorMsgCallback error_handler =
                boost::bind(&Dhcpv4Srv::ifaceMgrSocket4ErrorHandler, _1);
            IfaceMgr::instance().openSockets4(port_, use_bcast_, error_handler);
113
        }
114

115 116 117 118 119 120 121
        // Instantiate LeaseMgr
        LeaseMgrFactory::create(dbconfig);
        LOG_INFO(dhcp4_logger, DHCP4_DB_BACKEND_STARTED)
            .arg(LeaseMgrFactory::instance().getType())
            .arg(LeaseMgrFactory::instance().getName());

        // Instantiate allocation engine
122 123
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100,
                                            false /* false = IPv4 */));
124

125 126 127 128 129 130 131
        // Register hook points
        hook_index_pkt4_receive_   = Hooks.hook_index_pkt4_receive_;
        hook_index_subnet4_select_ = Hooks.hook_index_subnet4_select_;
        hook_index_pkt4_send_      = Hooks.hook_index_pkt4_send_;

        /// @todo call loadLibraries() when handling configuration changes

132
    } catch (const std::exception &e) {
133
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
134 135 136
        shutdown_ = true;
        return;
    }
137

Tomek Mrugalski's avatar
Tomek Mrugalski committed
138
    shutdown_ = false;
139 140 141
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
142
    IfaceMgr::instance().closeSockets();
143 144
}

145 146
void
Dhcpv4Srv::shutdown() {
147
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
148 149 150
    shutdown_ = true;
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
151 152
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
153 154 155
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
156 157
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
158 159 160
    IfaceMgr::instance().send(packet);
}

161 162
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
163
    while (!shutdown_) {
164
        /// @todo: calculate actual timeout once we have lease database
165 166
        //cppcheck-suppress variableScope This is temporary anyway
        const int timeout = 1000;
167

Tomek Mrugalski's avatar
Tomek Mrugalski committed
168
        // client's message and server's response
169
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
170
        Pkt4Ptr rsp;
171

172
        try {
173
            query = receivePacket(timeout);
174 175 176 177
        } catch (const std::exception& e) {
            LOG_ERROR(dhcp4_logger, DHCP4_PACKET_RECEIVE_FAIL).arg(e.what());
        }

178 179 180 181 182 183 184 185 186 187 188 189
        // Handle next signal received by the process. It must be called after
        // an attempt to receive a packet to properly handle server shut down.
        // The SIGTERM or SIGINT will be received prior to, or during execution
        // of select() (select is invoked by recivePacket()). When that happens,
        // select will be interrupted. The signal handler will be invoked
        // immediately after select(). The handler will set the shutdown flag
        // and cause the process to terminate before the next select() function
        // is called. If the function was called before receivePacket the
        // process could wait up to the duration of timeout of select() to
        // terminate.
        handleSignal();

190 191 192 193 194 195
        // Timeout may be reached or signal received, which breaks select()
        // with no reception ocurred
        if (!query) {
            continue;
        }

196 197 198 199 200 201 202 203 204
        // In order to parse the DHCP options, the server needs to use some
        // configuration information such as: existing option spaces, option
        // definitions etc. This is the kind of information which is not
        // available in the libdhcp, so we need to supply our own implementation
        // of the option parsing function here, which would rely on the
        // configuration data.
        query->setCallback(boost::bind(&Dhcpv4Srv::unpackOptions, this,
                                       _1, _2, _3));

205 206 207
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
208
        // data; execute callouts registered for buffer4_receive.
209
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
210 211 212 213 214 215 216 217 218
            CalloutHandlePtr callout_handle = getCalloutHandle(query);

            // Delete previously set arguments
            callout_handle->deleteAllArguments();

            // Pass incoming packet as argument
            callout_handle->setArgument("query4", query);

            // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
219 220
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236

            // Callouts decided to skip the next processing step. The next
            // processing step would to parse the packet, so skip at this
            // stage means that callouts did the parsing already, so server
            // should skip parsing.
            if (callout_handle->getSkip()) {
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_BUFFER_RCVD_SKIP);
                skip_unpack = true;
            }

            callout_handle->getArgument("query4", query);
        }

        // Unpack the packet information unless the buffer4_receive callouts
        // indicated they did it
        if (!skip_unpack) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
237 238 239
            try {
                query->unpack();
            } catch (const std::exception& e) {
240 241 242
                // Failed to parse the packet.
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_PARSE_FAIL).arg(e.what());
243 244
                continue;
            }
245
        }
246

Tomek Mrugalski's avatar
Tomek Mrugalski committed
247 248 249
        // Assign this packet to one or more classes if needed. We need to do
        // this before calling accept(), because getSubnet4() may need client
        // class information.
250 251
        classifyPacket(query);

252 253 254
        // Check whether the message should be further processed or discarded.
        // There is no need to log anything here. This function logs by itself.
        if (!accept(query)) {
255
            continue;
256
        }
257

258
        // We have sanity checked (in accept() that the Message Type option
259 260
        // exists, so we can safely get it here.
        int type = query->getType();
261
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_RECEIVED)
262
            .arg(serverReceivedPacketName(type))
263
            .arg(type)
264 265
            .arg(query->getIface());
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
266
            .arg(type)
267 268
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
269
        // Let's execute all callouts registered for pkt4_receive
270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289
        if (HooksManager::calloutsPresent(hook_index_pkt4_receive_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);

            // Delete previously set arguments
            callout_handle->deleteAllArguments();

            // Pass incoming packet as argument
            callout_handle->setArgument("query4", query);

            // Call callouts
            HooksManager::callCallouts(hook_index_pkt4_receive_,
                                       *callout_handle);

            // Callouts decided to skip the next processing step. The next
            // processing step would to process the packet, so skip at this
            // stage means drop.
            if (callout_handle->getSkip()) {
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP);
                continue;
            }
290

291 292
            callout_handle->getArgument("query4", query);
        }
293

294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323
        try {
            switch (query->getType()) {
            case DHCPDISCOVER:
                rsp = processDiscover(query);
                break;

            case DHCPREQUEST:
                // Note that REQUEST is used for many things in DHCPv4: for
                // requesting new leases, renewing existing ones and even
                // for rebinding.
                rsp = processRequest(query);
                break;

            case DHCPRELEASE:
                processRelease(query);
                break;

            case DHCPDECLINE:
                processDecline(query);
                break;

            case DHCPINFORM:
                processInform(query);
                break;

            default:
                // Only action is to output a message if debug is enabled,
                // and that is covered by the debug statement before the
                // "switch" statement.
                ;
324
            }
325 326 327 328 329 330 331 332 333 334 335 336 337 338
        } catch (const isc::Exception& e) {

            // Catch-all exception (at least for ones based on the isc
            // Exception class, which covers more or less all that
            // are explicitly raised in the BIND 10 code).  Just log
            // the problem and ignore the packet. (The problem is logged
            // as a debug message because debug is disabled by default -
            // it prevents a DDOS attack based on the sending of problem
            // packets.)
            if (dhcp4_logger.isDebugEnabled(DBG_DHCP4_BASIC)) {
                std::string source = "unknown";
                HWAddrPtr hwptr = query->getHWAddr();
                if (hwptr) {
                    source = hwptr->toText();
339
                }
340 341 342
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC,
                          DHCP4_PACKET_PROCESS_FAIL)
                    .arg(source).arg(e.what());
343
            }
344
        }
345

346 347 348
        if (!rsp) {
            continue;
        }
349

Tomek Mrugalski's avatar
Tomek Mrugalski committed
350 351 352 353 354
        // Let's do class specific processing. This is done before
        // pkt4_send.
        //
        /// @todo: decide whether we want to add a new hook point for
        /// doing class specific processing.
355 356 357 358 359 360 361
        if (!classSpecificProcessing(query, rsp)) {
            /// @todo add more verbosity here
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_PROCESSING_FAILED);

            continue;
        }

362 363
        // Specifies if server should do the packing
        bool skip_pack = false;
364

Tomek Mrugalski's avatar
Tomek Mrugalski committed
365
        // Execute all callouts registered for pkt4_send
366 367
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
368

369 370
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
371

372 373
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
374

375 376
            // Set our response
            callout_handle->setArgument("response4", rsp);
377

378 379 380
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
381

382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403
            // Callouts decided to skip the next processing step. The next
            // processing step would to send the packet, so skip at this
            // stage means "drop response".
            if (callout_handle->getSkip()) {
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP);
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
                rsp->pack();
            } catch (const std::exception& e) {
                LOG_ERROR(dhcp4_logger, DHCP4_PACKET_SEND_FAIL)
                    .arg(e.what());
            }
        }

        try {
            // Now all fields and options are constructed into output wire buffer.
            // Option objects modification does not make sense anymore. Hooks
            // can only manipulate wire buffer at this stage.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
404
            // Let's execute all callouts registered for buffer4_send
405
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
406
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
407

408 409
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
410

411 412
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
413

414
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
415 416
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
417

418 419 420 421
                // Callouts decided to skip the next processing step. The next
                // processing step would to parse the packet, so skip at this
                // stage means drop.
                if (callout_handle->getSkip()) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
422 423
                    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS,
                              DHCP4_HOOK_BUFFER_SEND_SKIP);
424
                    continue;
425
                }
426 427

                callout_handle->getArgument("response4", rsp);
428
            }
429 430 431 432 433 434 435 436 437

            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA,
                      DHCP4_RESPONSE_DATA)
                .arg(static_cast<int>(rsp->getType())).arg(rsp->toText());

            sendPacket(rsp);
        } catch (const std::exception& e) {
            LOG_ERROR(dhcp4_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(e.what());
438
        }
439 440 441 442 443
    }

    return (true);
}

444
string
445
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461
    if (!srvid) {
        isc_throw(BadValue, "NULL pointer passed to srvidToString()");
    }
    boost::shared_ptr<Option4AddrLst> generated =
        boost::dynamic_pointer_cast<Option4AddrLst>(srvid);
    if (!srvid) {
        isc_throw(BadValue, "Pointer to invalid option passed to srvidToString()");
    }

    Option4AddrLst::AddressContainer addrs = generated->getAddresses();
    if (addrs.size() != 1) {
        isc_throw(BadValue, "Malformed option passed to srvidToString(). "
                  << "Expected to contain a single IPv4 address.");
    }

    return (addrs[0].toText());
462 463
}

464
isc::dhcp_ddns::D2Dhcid
465 466 467 468 469 470 471 472 473
Dhcpv4Srv::computeDhcid(const Lease4Ptr& lease) {
    if (!lease) {
        isc_throw(DhcidComputeError, "a pointer to the lease must be not"
                  " NULL to compute DHCID");

    } else if (lease->hostname_.empty()) {
        isc_throw(DhcidComputeError, "unable to compute the DHCID for the"
                  " lease which has empty hostname set");

474 475
    }

476 477 478 479 480 481 482 483 484
    // In order to compute DHCID the client's hostname must be encoded in
    // canonical wire format. It is unlikely that the FQDN is malformed
    // because it is validated by the classes which encapsulate options
    // carrying client FQDN. However, if the client name was carried in the
    // Hostname option it is more likely as it carries the hostname as a
    // regular string.
    std::vector<uint8_t> fqdn_wire;
    try {
        OptionDataTypeUtil::writeFqdn(lease->hostname_, fqdn_wire, true);
485

486 487 488
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
489 490

    }
491 492 493

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
494
    try {
495 496 497 498 499 500 501
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
            HWAddrPtr hwaddr(new HWAddr(lease->hwaddr_, HTYPE_ETHER));
            return (D2Dhcid(hwaddr, fqdn_wire));
        }
502
    } catch (const Exception& ex) {
503 504
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
505

506
    }
507 508 509

}

510 511
void
Dhcpv4Srv::copyDefaultFields(const Pkt4Ptr& question, Pkt4Ptr& answer) {
512 513 514
    answer->setIface(question->getIface());
    answer->setIndex(question->getIndex());
    answer->setCiaddr(question->getCiaddr());
515

516
    answer->setSiaddr(IOAddress("0.0.0.0")); // explicitly set this to 0
517
    answer->setHops(question->getHops());
518 519

    // copy MAC address
520
    answer->setHWAddr(question->getHWAddr());
521 522

    // relay address
523 524
    answer->setGiaddr(question->getGiaddr());

525
    // Let's copy client-id to response. See RFC6842.
526 527
    // It is possible to disable RFC6842 to keep backward compatibility
    bool echo = CfgMgr::instance().echoClientId();
528
    OptionPtr client_id = question->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
529
    if (client_id && echo) {
530 531
        answer->addOption(client_id);
    }
532 533

    // If src/dest HW addresses are used by the packet filtering class
534 535 536 537 538 539
    // we need to copy them as well. There is a need to check that the
    // address being set is not-NULL because an attempt to set the NULL
    // HW would result in exception. If these values are not set, the
    // the default HW addresses (zeroed) should be generated by the
    // packet filtering class when creating Ethernet header for
    // outgoing packet.
540 541
    HWAddrPtr src_hw_addr = question->getLocalHWAddr();
    if (src_hw_addr) {
542
        answer->setLocalHWAddr(src_hw_addr);
543
    }
544
    HWAddrPtr dst_hw_addr = question->getRemoteHWAddr();
545
    if (dst_hw_addr) {
546
        answer->setRemoteHWAddr(dst_hw_addr);
547
    }
548 549 550 551 552 553

    // If this packet is relayed, we want to copy Relay Agent Info option
    OptionPtr rai = question->getOption(DHO_DHCP_AGENT_OPTIONS);
    if (rai) {
        answer->addOption(rai);
    }
554 555
}

556 557
void
Dhcpv4Srv::appendDefaultOptions(Pkt4Ptr& msg, uint8_t msg_type) {
558
    OptionPtr opt;
559 560

    // add Message Type Option (type 53)
561
    msg->setType(msg_type);
562 563 564 565

    // more options will be added here later
}

566 567 568 569 570
void
Dhcpv4Srv::appendServerID(const Pkt4Ptr& response) {
    // The source address for the outbound message should have been set already.
    // This is the address that to the best of the server's knowledge will be
    // available from the client.
571 572
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
573 574 575 576 577
    response->addOption(OptionPtr(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                                     response->getLocalAddr()))
                        );
}

578 579
void
Dhcpv4Srv::appendRequestedOptions(const Pkt4Ptr& question, Pkt4Ptr& msg) {
580 581 582 583 584 585 586 587 588 589 590

    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
    Subnet4Ptr subnet = selectSubnet(question);
    // If we can't find the subnet for the client there is no way
    // to get the options to be sent to a client. We don't log an
    // error because it will be logged by the assignLease method
    // anyway.
    if (!subnet) {
        return;
    }
591

592 593 594 595 596 597 598 599 600
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
        OptionUint8Array>(question->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
601

602 603 604 605 606 607
    // Get the codes of requested options.
    const std::vector<uint8_t>& requested_opts = option_prl->getValues();
    // For each requested option code get the instance of the option
    // to be returned to the client.
    for (std::vector<uint8_t>::const_iterator opt = requested_opts.begin();
         opt != requested_opts.end(); ++opt) {
608 609 610 611 612 613
        if (!msg->getOption(*opt)) {
            Subnet::OptionDescriptor desc =
                subnet->getOptionDescriptor("dhcp4", *opt);
            if (desc.option && !msg->getOption(*opt)) {
                msg->addOption(desc.option);
            }
614 615
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
616
}
617

618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640
void
Dhcpv4Srv::appendRequestedVendorOptions(const Pkt4Ptr& question, Pkt4Ptr& answer) {
    // Get the configured subnet suitable for the incoming packet.
    Subnet4Ptr subnet = selectSubnet(question);
    // Leave if there is no subnet matching the incoming packet.
    // There is no need to log the error message here because
    // it will be logged in the assignLease() when it fails to
    // pick the suitable subnet. We don't want to duplicate
    // error messages in such case.
    if (!subnet) {
        return;
    }

    // Try to get the vendor option
    boost::shared_ptr<OptionVendor> vendor_req =
        boost::dynamic_pointer_cast<OptionVendor>(question->getOption(DHO_VIVSO_SUBOPTIONS));
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
641 642
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
643 644
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
645 646 647 648 649 650 651 652 653 654

    // Option ORO not found. Don't do anything then.
    if (!oro) {
        return;
    }

    boost::shared_ptr<OptionVendor> vendor_rsp(new OptionVendor(Option::V4, vendor_id));

    // Get the list of options that client requested.
    bool added = false;
655
    const std::vector<uint8_t>& requested_opts = oro->getValues();
656

Tomek Mrugalski's avatar
Tomek Mrugalski committed
657
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
658
         code != requested_opts.end(); ++code) {
659 660 661 662 663 664 665
        if  (!vendor_rsp->getOption(*code)) {
            Subnet::OptionDescriptor desc = subnet->getVendorOptionDescriptor(vendor_id,
                                                                              *code);
            if (desc.option) {
                vendor_rsp->addOption(desc.option);
                added = true;
            }
666 667
        }

668 669
        if (added) {
            answer->addOption(vendor_rsp);
670 671
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
672
}
673

674

675 676 677 678 679 680 681 682
void
Dhcpv4Srv::appendBasicOptions(const Pkt4Ptr& question, Pkt4Ptr& msg) {
    // Identify options that we always want to send to the
    // client (if they are configured).
    static const uint16_t required_options[] = {
        DHO_ROUTERS,
        DHO_DOMAIN_NAME_SERVERS,
        DHO_DOMAIN_NAME };
683

684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
    Subnet4Ptr subnet = selectSubnet(question);
    if (!subnet) {
        return;
    }

    // Try to find all 'required' options in the outgoing
    // message. Those that are not present will be added.
    for (int i = 0; i < required_options_size; ++i) {
        OptionPtr opt = msg->getOption(required_options[i]);
        if (!opt) {
            // Check whether option has been configured.
            Subnet::OptionDescriptor desc =
                subnet->getOptionDescriptor("dhcp4", required_options[i]);
            if (desc.option) {
                msg->addOption(desc.option);
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
706
}
707

708 709 710 711 712
void
Dhcpv4Srv::processClientName(const Pkt4Ptr& query, Pkt4Ptr& answer) {
    // It is possible that client has sent both Client FQDN and Hostname
    // option. In such case, server should prefer Client FQDN option and
    // ignore the Hostname option.
713 714 715 716 717 718 719
    try {
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
            (query->getOption(DHO_FQDN));
        if (fqdn) {
            processClientFqdnOption(fqdn, answer);

        } else {
720
            OptionStringPtr hostname = boost::dynamic_pointer_cast<OptionString>
721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736
                (query->getOption(DHO_HOST_NAME));
            if (hostname) {
                processHostnameOption(hostname, answer);
            }
        }
    } catch (const Exception& ex) {
        // In some rare cases it is possible that the client's name processing
        // fails. For example, the Hostname option may be malformed, or there
        // may be an error in the server's logic which would cause multiple
        // attempts to add the same option to the response message. This
        // error message aggregates all these errors so they can be diagnosed
        // from the log. We don't want to throw an exception here because,
        // it will impact the processing of the whole packet. We rather want
        // the processing to continue, even if the client's name is wrong.
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
            .arg(ex.what());
737 738 739 740
    }
}

void
741 742 743 744 745 746
Dhcpv4Srv::processClientFqdnOption(const Option4ClientFqdnPtr& fqdn,
                                   Pkt4Ptr& answer) {
    // Create the DHCPv4 Client FQDN Option to be included in the server's
    // response to a client.
    Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));

747 748 749 750
    // Set the server S, N, and O flags based on client's flags and
    // current configuration.
    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
    d2_mgr.adjustFqdnFlags<Option4ClientFqdn>(*fqdn, *fqdn_resp);
751

752 753 754
    // Carry over the client's E flag.
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E,
                       fqdn->getFlag(Option4ClientFqdn::FLAG_E));
755 756


757 758 759
    // Adjust the domain name based on domain name value and type sent by the
    // client and current configuration.
    d2_mgr.adjustDomainName<Option4ClientFqdn>(*fqdn, *fqdn_resp);
760 761 762 763 764 765 766 767 768 769 770 771 772

    // Add FQDN option to the response message. Note that, there may be some
    // cases when server may choose not to include the FQDN option in a
    // response to a client. In such cases, the FQDN should be removed from the
    // outgoing message. In theory we could cease to include the FQDN option
    // in this function until it is confirmed that it should be included.
    // However, we include it here for simplicity. Functions used to acquire
    // lease for a client will scan the response message for FQDN and if it
    // is found they will take necessary actions to store the FQDN information
    // in the lease database as well as to generate NameChangeRequests to DNS.
    // If we don't store the option in the reponse message, we will have to
    // propagate it in the different way to the functions which acquire the
    // lease. This would require modifications to the API of this class.
773
    answer->addOption(fqdn_resp);
774 775 776
}

void
777
Dhcpv4Srv::processHostnameOption(const OptionStringPtr& opt_hostname,
778
                                 Pkt4Ptr& answer) {
779 780 781
    // Fetch D2 configuration.
    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();

782
    // Do nothing if the DNS updates are disabled.
783
    if (!d2_mgr.ddnsEnabled()) {
784 785 786
        return;
    }

787
    std::string hostname = isc::util::str::trim(opt_hostname->getValue());
788
    unsigned int label_count = OptionDataTypeUtil::getLabelCount(hostname);
789
    // The hostname option sent by the client should be at least 1 octet long.
790 791 792
    // If it isn't we ignore this option. (Per RFC 2131, section 3.14)
    /// @todo It would be more liberal to accept this and let it fall into
    /// the case  of replace or less than two below.
793 794 795 796
    if (label_count == 0) {
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_EMPTY_HOSTNAME);
        return;
    }
797 798 799 800
    // Copy construct the hostname provided by the client. It is entirely
    // possible that we will use the hostname option provided by the client
    // to perform the DNS update and we will send the same option to him to
    // indicate that we accepted this hostname.
801
    OptionStringPtr opt_hostname_resp(new OptionString(*opt_hostname));
802 803 804 805 806 807 808 809

    // The hostname option may be unqualified or fully qualified. The lab_count
    // holds the number of labels for the name. The number of 1 means that
    // there is only root label "." (even for unqualified names, as the
    // getLabelCount function treats each name as a fully qualified one).
    // By checking the number of labels present in the hostname we may infer
    // whether client has sent the fully qualified or unqualified hostname.

810 811 812 813 814 815 816 817
    /// @todo We may want to reconsider whether it is appropriate for the
    /// client to send a root domain name as a Hostname. There are
    /// also extensions to the auto generation of the client's name,
    /// e.g. conversion to the puny code which may be considered at some point.
    /// For now, we just remain liberal and expect that the DNS will handle
    /// conversion if needed and possible.
    if ((d2_mgr.getD2ClientConfig()->getReplaceClientName()) ||
        (label_count < 2)) {
818 819 820
        // Set to root domain to signal later on that we should replace it.
        // DHO_HOST_NAME is a string option which cannot be empty.
        opt_hostname_resp->setValue(".");
821
    } else if (label_count == 2) {
822 823 824
        // If there are two labels, it means that the client has specified
        // the unqualified name. We have to concatenate the unqalified name
        // with the domain name.
825
        opt_hostname_resp->setValue(d2_mgr.qualifyName(hostname));
826 827 828
    }

    answer->addOption(opt_hostname_resp);
829 830
}

831 832
void
Dhcpv4Srv::createNameChangeRequests(const Lease4Ptr& lease,
833
                                    const Lease4Ptr& old_lease) {
834 835 836 837 838
    if (!lease) {
        isc_throw(isc::Unexpected,
                  "NULL lease specified when creating NameChangeRequest");
    }

839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857
    // If old lease is not NULL, it is an indication that the lease has
    // just been renewed. In such case we may need to generate the
    // additional NameChangeRequest to remove an existing entry before
    // we create a NameChangeRequest to add the entry for an updated lease.
    // We may also decide not to generate any requests at all. This is when
    // we discover that nothing has changed in the client's FQDN data.
    if (old_lease) {
        if (!lease->matches(*old_lease)) {
            isc_throw(isc::Unexpected,
                      "there is no match between the current instance of the"
                      " lease: " << lease->toText() << ", and the previous"
                      " instance: " << lease->toText());
        } else {
            // There will be a NameChangeRequest generated to remove existing
            // DNS entries if the following conditions are met:
            // - The hostname is set for the existing lease, we can't generate
            //   removal request for non-existent hostname.
            // - A server has performed reverse, forward or both updates.
            // - FQDN data between the new and old lease do not match.
858
            if (!lease->hasIdenticalFqdn(*old_lease)) {
859 860
                queueNameChangeRequest(isc::dhcp_ddns::CHG_REMOVE,
                                       old_lease);
861 862

            // If FQDN data from both leases match, there is no need to update.
863
            } else if (lease->hasIdenticalFqdn(*old_lease)) {
864
                return;
865

866 867 868 869 870
            }

        }
    }

871 872 873 874
    // We may need to generate the NameChangeRequest for the new lease. It
    // will be generated only if hostname is set and if forward or reverse
    // update has been requested.
    queueNameChangeRequest(isc::dhcp_ddns::CHG_ADD, lease);
875 876
}

877 878
void
Dhcpv4Srv::
879 880 881 882 883 884 885 886
queueNameChangeRequest(const isc::dhcp_ddns::NameChangeType chg_type,
                       const Lease4Ptr& lease) {
    // The hostname must not be empty, and at least one type of update
    // should be requested.
    if (!lease || lease->hostname_.empty() ||
        (!lease->fqdn_rev_ && !lease->fqdn_fwd_)) {
        return;
    }
887 888

    // Create the DHCID for the NameChangeRequest.
889 890 891 892 893 894 895 896 897
    D2Dhcid dhcid;
    try {
        dhcid  = computeDhcid(lease);
    } catch (const DhcidComputeError& ex) {
        LOG_ERROR(dhcp4_logger, DHCP4_DHCID_COMPUTE_ERROR)
            .arg(lease->toText())
            .arg(ex.what());
        return;
    }
898

899
    // Create NameChangeRequest
900 901 902 903 904 905 906 907 908
    NameChangeRequestPtr ncr(new NameChangeRequest(chg_type, lease->fqdn_fwd_,
                                                   lease->fqdn_rev_,
                                                   lease->hostname_,
                                                   lease->addr_.toText(),
                                                   dhcid,
                                                   (lease->cltt_ +
                                                    lease->valid_lft_),
                                                   lease->valid_lft_));

909 910
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUEUE_NCR)
        .arg(chg_type == CHG_ADD ? "add" : "remove")
911
        .arg(ncr->toText());
912

913 914
    // And pass it to the the manager.
    CfgMgr::instance().getD2ClientMgr().sendRequest(ncr);
915
}
916

917 918
void
Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
919 920 921 922 923 924 925 926 927 928 929 930

    // We need to select a subnet the client is connected in.
    Subnet4Ptr subnet = selectSubnet(question);
    if (!subnet) {
        // This particular client is out of luck today. We do not have
        // information about the subnet he is connected to. This likely means
        // misconfiguration of the server (or some relays). We will continue to
        // process this message, but our response will be almost useless: no
        // addresses or prefixes, no subnet specific configuration etc. The only
        // thing this client can get is some global information (like DNS
        // servers).

931 932
        // perhaps this should be logged on some higher level? This is most
        // likely configuration bug.
933 934 935
        LOG_ERROR(dhcp4_logger, DHCP4_SUBNET_SELECTION_FAILED)
            .arg(question->getRemoteAddr().toText())
            .arg(serverReceivedPacketName(question->getType()));
936
        answer->setType(DHCPNAK);
937 938 939
        answer->setYiaddr(IOAddress("0.0.0.0"));
        return;
    }
940

941 942 943 944
    // Set up siaddr. Perhaps assignLease is not the best place to call this
    // as siaddr has nothing to do with a lease, but otherwise we would have
    // to select subnet twice (performance hit) or update too many functions
    // at once.
945
    /// @todo: move subnet selection to a common code
946 947
    answer->setSiaddr(subnet->getSiaddr());

948 949 950
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_SELECTED)
        .arg(subnet->toText());

951 952 953 954 955 956 957
    // Get client-id option
    ClientIdPtr client_id;
    OptionPtr opt = question->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (opt) {
        client_id = ClientIdPtr(new ClientId(opt->getData()));
    }
    // client-id is not mandatory in DHCPv4
958

959
    IOAddress hint = question->getYiaddr();
960

961
    HWAddrPtr hwaddr = question->getHWAddr();
962

963 964 965 966 967 968
    // "Fake" allocation is processing of DISCOVER message. We pretend to do an
    // allocation, but we do not put the lease in the database. That is ok,
    // because we do not guarantee that the user will get that exact lease. If
    // the user selects this server to do actual allocation (i.e. sends REQUEST)
    // it should include this hint. That will help us during the actual lease
    // allocation.
969
    bool fake_allocation = (question->getType() == DHCPDISCOVER);
970

971 972
    CalloutHandlePtr callout_handle = getCalloutHandle(question);

973 974 975
    std::string hostname;
    bool fqdn_fwd = false;
    bool fqdn_rev = false;
976
    OptionStringPtr opt_hostname;
977 978 979 980
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(answer->getOption(DHO_FQDN));
    if (fqdn) {
        hostname = fqdn->getDomainName();
981 982 983
        CfgMgr::instance().getD2ClientMgr().getUpdateDirections(*fqdn,
                                                                fqdn_fwd,
                                                                fqdn_rev);
984
    } else {
985
        opt_hostname = boost::dynamic_pointer_cast<OptionString>
986
            (answer->getOption(DHO_HOST_NAME));
987
        if (opt_hostname) {
988 989 990 991 992 993 994 995
            hostname = opt_hostname->getValue();
            // DHO_HOST_NAME is string option which cannot be blank,
            // we use "." to know we should replace it with a fully
            // generated name. The local string variable needs to be
            // blank in logic below.
            if (hostname == ".") {
                hostname = "";
            }
996 997
            /// @todo It could be configurable what sort of updates the
            /// server is doing when Hostname option was sent.
998 999 1000
            fqdn_fwd = true;
            fqdn_rev = true;
        }
1001 1002
    }

1003 1004 1005 1006
    // Use allocation engine to pick a lease for this client. Allocation engine
    // will try to honour the hint, but it is just a hint - some other address
    // may be used instead. If fake_allocation is set to false, the lease will
    // be inserted into the LeaseMgr as well.
1007
    /// @todo pass the actual FQDN data.
1008
    Lease4Ptr old_lease;
1009
    Lease4Ptr lease = alloc_engine_->allocateLease4(subnet, client_id, hwaddr,
1010 1011
                                                      hint, fqdn_fwd, fqdn_rev,
                                                      hostname,
1012 1013 1014
                                                    fake_allocation,
                                                    callout_handle,
                                                    old_lease);
1015 1016

    if (lease) {
1017 1018
        // We have a lease! Let's set it in the packet and send it back to
        // the client.
1019 1020
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, fake_allocation?
                  DHCP4_LEASE_ADVERT:DHCP4_LEASE_ALLOC)