dhcp4_srv.cc 58.3 KB
Newer Older
1
// Copyright (C) 2011-2013 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 24 25
#include <dhcp/pkt4.h>
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
26 27
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
28 29 30 31 32
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
#include <dhcpsrv/subnet.h>
#include <dhcpsrv/utils.h>
33
#include <dhcpsrv/utils.h>
34
#include <hooks/callout_handle.h>
35
#include <hooks/hooks_manager.h>
36

37 38 39 40 41
#include <boost/algorithm/string/erase.hpp>

#include <iomanip>
#include <fstream>

42 43
using namespace isc;
using namespace isc::asiolink;
44
using namespace isc::dhcp;
45
using namespace isc::dhcp_ddns;
46
using namespace isc::hooks;
47 48
using namespace isc::log;
using namespace std;
49

50
/// Structure that holds registered hook indexes
51 52
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
53 54
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
55
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
56
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
57
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
58

59 60 61
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
62 63 64
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
65 66
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
67 68 69 70 71 72 73
    }
};

// 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.
74
Dhcp4Hooks Hooks;
75

76 77 78
namespace isc {
namespace dhcp {

79 80
namespace {

81
// @todo The following constants describe server's behavior with respect to the
82 83 84
// DHCPv4 Client FQDN Option sent by a client. They will be removed
// when DDNS parameters for DHCPv4 are implemented with the ticket #3033.

85 86 87 88 89
// @todo Additional configuration parameter which we may consider is the one
// that controls whether the DHCP server sends the removal NameChangeRequest
// if it discovers that the entry for the particular client exists or that
// it always updates the DNS.

90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108
// Should server always include the FQDN option in its response, regardless
// if it has been requested in Parameter Request List Option (Disabled).
const bool FQDN_ALWAYS_INCLUDE = false;
// Enable A RR update delegation to the client (Disabled).
const bool FQDN_ALLOW_CLIENT_UPDATE = false;
// Globally enable updates (Enabled).
const bool FQDN_ENABLE_UPDATE = true;
// Do update, even if client requested no updates with N flag (Disabled).
const bool FQDN_OVERRIDE_NO_UPDATE = false;
// Server performs an update when client requested delegation (Enabled).
const bool FQDN_OVERRIDE_CLIENT_UPDATE = true;
// The fully qualified domain-name suffix if partial name provided by
// a client.
const char* FQDN_PARTIAL_SUFFIX = "example.com";
// Should server replace the domain-name supplied by the client (Disabled).
const bool FQDN_REPLACE_CLIENT_NAME = false;

}

109 110 111 112 113 114 115 116 117
/// @brief file name of a server-id file
///
/// Server must store its server identifier in persistent storage that must not
/// change between restarts. This is name of the file that is created in dataDir
/// (see isc::dhcp::CfgMgr::getDataDir()). It is a text file that uses
/// regular IPv4 address, e.g. 192.0.2.1. Server will create it during
/// first run and then use it afterwards.
static const char* SERVER_ID_FILE = "b10-dhcp4-serverid";

118 119 120
// These are hardcoded parameters. Currently this is a skeleton server that only
// grants those options and a single, fixed, hardcoded lease.

121
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const char* dbconfig, const bool use_bcast,
122
                     const bool direct_response_desired)
123 124
: serverid_(), shutdown_(true), alloc_engine_(), port_(port),
    use_bcast_(use_bcast), hook_index_pkt4_receive_(-1),
125 126
    hook_index_subnet4_select_(-1), hook_index_pkt4_send_(-1) {

127
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
128
    try {
129
        // First call to instance() will create IfaceMgr (it's a singleton)
130
        // it may throw something if things go wrong.
131
        // The 'true' value of the call to setMatchingPacketFilter imposes
132 133 134 135
        // 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.
136
        IfaceMgr::instance().setMatchingPacketFilter(direct_response_desired);
137

138 139 140
        if (port) {
            // open sockets only if port is non-zero. Port 0 is used
            // for non-socket related testing.
141
            IfaceMgr::instance().openSockets4(port_, use_bcast_);
142
        }
143

144 145 146
        string srvid_file = CfgMgr::instance().getDataDir() + "/" + string(SERVER_ID_FILE);
        if (loadServerID(srvid_file)) {
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_SERVERID_LOADED)
147
                .arg(srvidToString(getServerID()))
148 149 150 151 152 153 154 155 156 157 158 159 160
                .arg(srvid_file);
        } else {
            generateServerID();
            LOG_INFO(dhcp4_logger, DHCP4_SERVERID_GENERATED)
                .arg(srvidToString(getServerID()))
                .arg(srvid_file);

            if (!writeServerID(srvid_file)) {
                LOG_WARN(dhcp4_logger, DHCP4_SERVERID_WRITE_FAIL)
                    .arg(srvid_file);
            }

        }
161

162 163 164 165 166 167 168 169 170
        // Instantiate LeaseMgr
        LeaseMgrFactory::create(dbconfig);
        LOG_INFO(dhcp4_logger, DHCP4_DB_BACKEND_STARTED)
            .arg(LeaseMgrFactory::instance().getType())
            .arg(LeaseMgrFactory::instance().getName());

        // Instantiate allocation engine
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100));

171 172 173 174 175 176 177
        // 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

178
    } catch (const std::exception &e) {
179
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
180 181 182
        shutdown_ = true;
        return;
    }
183

Tomek Mrugalski's avatar
Tomek Mrugalski committed
184
    shutdown_ = false;
185 186 187
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
188
    IfaceMgr::instance().closeSockets();
189 190
}

191 192
void
Dhcpv4Srv::shutdown() {
193
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
194 195 196
    shutdown_ = true;
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
197 198
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
199 200 201
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
202 203
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
204 205 206
    IfaceMgr::instance().send(packet);
}

207 208
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
209
    while (!shutdown_) {
210
        /// @todo: calculate actual timeout once we have lease database
211 212
        //cppcheck-suppress variableScope This is temporary anyway
        const int timeout = 1000;
213

Tomek Mrugalski's avatar
Tomek Mrugalski committed
214
        // client's message and server's response
215
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
216
        Pkt4Ptr rsp;
217

218
        try {
219
            query = receivePacket(timeout);
220 221 222 223
        } catch (const std::exception& e) {
            LOG_ERROR(dhcp4_logger, DHCP4_PACKET_RECEIVE_FAIL).arg(e.what());
        }

224 225 226 227 228 229 230 231 232
        // Timeout may be reached or signal received, which breaks select()
        // with no reception ocurred
        if (!query) {
            continue;
        }

        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
233
        // data; execute callouts registered for buffer4_receive.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
234 235
        if (HooksManager::getHooksManager()
            .calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
236 237 238 239 240 241 242 243 244
            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
245 246
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262

            // 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
263 264 265
            try {
                query->unpack();
            } catch (const std::exception& e) {
266 267 268
                // Failed to parse the packet.
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_PARSE_FAIL).arg(e.what());
269 270
                continue;
            }
271
        }
272

273 274 275 276 277
        // When receiving a packet without message type option, getType() will
        // throw. Let's set type to -1 as default error indicator.
        int type = -1;
        try {
            type = query->getType();
278 279 280 281
        } catch (...) {
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_NO_TYPE)
                .arg(query->getIface());
            continue;
282
        }
283

284
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_RECEIVED)
285
            .arg(serverReceivedPacketName(type))
286
            .arg(type)
287 288
            .arg(query->getIface());
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
289
            .arg(type)
290 291
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
292
        // Let's execute all callouts registered for pkt4_receive
293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312
        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;
            }
313

314 315
            callout_handle->getArgument("query4", query);
        }
316

317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346
        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.
                ;
347
            }
348 349 350 351 352 353 354 355 356 357 358 359 360 361
        } 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();
362
                }
363 364 365
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC,
                          DHCP4_PACKET_PROCESS_FAIL)
                    .arg(source).arg(e.what());
366
            }
367
        }
368

369 370 371
        if (!rsp) {
            continue;
        }
372

373
        adjustRemoteAddr(query, rsp);
374

375 376 377 378 379
        if (!rsp->getHops()) {
            rsp->setRemotePort(DHCP4_CLIENT_PORT);
        } else {
            rsp->setRemotePort(DHCP4_SERVER_PORT);
        }
380

381 382 383 384
        rsp->setLocalAddr(query->getLocalAddr());
        rsp->setLocalPort(DHCP4_SERVER_PORT);
        rsp->setIface(query->getIface());
        rsp->setIndex(query->getIndex());
385

386 387
        // Specifies if server should do the packing
        bool skip_pack = false;
388

Tomek Mrugalski's avatar
Tomek Mrugalski committed
389
        // Execute all callouts registered for pkt4_send
390 391
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
392

393 394
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
395

396 397
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
398

399 400
            // Set our response
            callout_handle->setArgument("response4", rsp);
401

402 403 404
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
405

406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
            // 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
428 429 430
            // Let's execute all callouts registered for buffer4_send
            if (HooksManager::getHooksManager()
                .calloutsPresent(Hooks.hook_index_buffer4_send_)) {
431
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
432

433 434
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
435

436 437
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
438

439
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
440 441
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
442

443 444 445 446
                // 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
447 448
                    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS,
                              DHCP4_HOOK_BUFFER_SEND_SKIP);
449
                    continue;
450
                }
451 452

                callout_handle->getArgument("response4", rsp);
453
            }
454 455 456 457 458 459 460 461 462

            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());
463
        }
464 465 466

        // Send NameChangeRequests to the b10-dhcp_ddns module.
        sendNameChangeRequests();
467 468 469 470 471
    }

    return (true);
}

472 473
bool
Dhcpv4Srv::loadServerID(const std::string& file_name) {
474

475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490
    // load content of the file into a string
    fstream f(file_name.c_str(), ios::in);
    if (!f.is_open()) {
        return (false);
    }

    string hex_string;
    f >> hex_string;
    f.close();

    // remove any spaces
    boost::algorithm::erase_all(hex_string, " ");

    try {
        IOAddress addr(hex_string);

Tomek Mrugalski's avatar
Tomek Mrugalski committed
491
        if (!addr.isV4()) {
492 493 494 495 496 497 498 499 500 501
            return (false);
        }

        // Now create server-id option
        serverid_.reset(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER, addr));

    } catch(...) {
        // any kind of malformed input (empty string, IPv6 address, complete
        // garbate etc.)
        return (false);
502 503 504 505 506
    }

    return (true);
}

507 508
void
Dhcpv4Srv::generateServerID() {
509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525

    const IfaceMgr::IfaceCollection& ifaces = IfaceMgr::instance().getIfaces();

    // Let's find suitable interface.
    for (IfaceMgr::IfaceCollection::const_iterator iface = ifaces.begin();
         iface != ifaces.end(); ++iface) {

        // Let's don't use loopback.
        if (iface->flag_loopback_) {
            continue;
        }

        // Let's skip downed interfaces. It is better to use working ones.
        if (!iface->flag_up_) {
            continue;
        }

526
        const Iface::AddressCollection addrs = iface->getAddresses();
527

528
        for (Iface::AddressCollection::const_iterator addr = addrs.begin();
529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544
             addr != addrs.end(); ++addr) {
            if (addr->getFamily() != AF_INET) {
                continue;
            }

            serverid_ = OptionPtr(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                                     *addr));
            return;
        }


    }

    isc_throw(BadValue, "No suitable interfaces for server-identifier found");
}

545 546
bool
Dhcpv4Srv::writeServerID(const std::string& file_name) {
547 548 549 550 551 552
    fstream f(file_name.c_str(), ios::out | ios::trunc);
    if (!f.good()) {
        return (false);
    }
    f << srvidToString(getServerID());
    f.close();
553
    return (true);
554 555
}

556
string
557
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573
    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());
574 575
}

576
isc::dhcp_ddns::D2Dhcid
577 578 579 580 581 582 583 584 585
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");

586 587
    }

588 589 590 591 592 593 594 595 596
    // 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);
597

598 599 600
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
601 602

    }
603 604 605

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
606
    try {
607 608 609 610 611 612 613
        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));
        }
614
    } catch (const Exception& ex) {
615 616
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
617

618
    }
619 620 621

}

622 623
void
Dhcpv4Srv::copyDefaultFields(const Pkt4Ptr& question, Pkt4Ptr& answer) {
624 625 626
    answer->setIface(question->getIface());
    answer->setIndex(question->getIndex());
    answer->setCiaddr(question->getCiaddr());
627

628
    answer->setSiaddr(IOAddress("0.0.0.0")); // explicitly set this to 0
629
    answer->setHops(question->getHops());
630 631

    // copy MAC address
632
    answer->setHWAddr(question->getHWAddr());
633 634

    // relay address
635 636
    answer->setGiaddr(question->getGiaddr());

637
    // Let's copy client-id to response. See RFC6842.
638 639 640 641
    OptionPtr client_id = question->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (client_id) {
        answer->addOption(client_id);
    }
642 643

    // If src/dest HW addresses are used by the packet filtering class
644 645 646 647 648 649
    // 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.
650 651
    HWAddrPtr src_hw_addr = question->getLocalHWAddr();
    if (src_hw_addr) {
652
        answer->setLocalHWAddr(src_hw_addr);
653
    }
654
    HWAddrPtr dst_hw_addr = question->getRemoteHWAddr();
655
    if (dst_hw_addr) {
656
        answer->setRemoteHWAddr(dst_hw_addr);
657
    }
658 659
}

660 661
void
Dhcpv4Srv::appendDefaultOptions(Pkt4Ptr& msg, uint8_t msg_type) {
662
    OptionPtr opt;
663 664

    // add Message Type Option (type 53)
665
    msg->setType(msg_type);
666

Tomek Mrugalski's avatar
Tomek Mrugalski committed
667
    // DHCP Server Identifier (type 54)
668
    msg->addOption(getServerID());
Tomek Mrugalski's avatar
Tomek Mrugalski committed
669

670 671 672
    // more options will be added here later
}

673 674
void
Dhcpv4Srv::appendRequestedOptions(const Pkt4Ptr& question, Pkt4Ptr& msg) {
675 676 677 678 679 680 681 682 683 684 685

    // 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;
    }
686

687 688 689 690 691 692 693 694 695
    // 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;
    }
696

697 698 699 700 701 702 703 704 705 706 707 708
    // 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) {
        Subnet::OptionDescriptor desc =
            subnet->getOptionDescriptor("dhcp4", *opt);
        if (desc.option) {
            msg->addOption(desc.option);
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
709
}
710

711 712 713 714 715 716 717 718 719
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_SUBNET_MASK,
        DHO_ROUTERS,
        DHO_DOMAIN_NAME_SERVERS,
        DHO_DOMAIN_NAME };
720

721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742
    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
743
}
744

745 746 747 748 749 750 751 752
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.
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
        (query->getOption(DHO_FQDN));
    if (fqdn) {
753
        processClientFqdnOption(fqdn, answer);
754 755 756 757 758

    } else {
        OptionCustomPtr hostname = boost::dynamic_pointer_cast<OptionCustom>
            (query->getOption(DHO_HOST_NAME));
        if (hostname) {
759
            processHostnameOption(hostname, answer);
760 761 762 763 764 765
        }

    }
}

void
766 767 768 769 770 771 772 773 774 775 776
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));

    // RFC4702, section 4 - set 'NOS' flags to 0.
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_S, 0);
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_O, 0);
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_N, 0);

777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816
    // Conditions when N flag has to be set to indicate that server will not
    // perform DNS updates:
    // 1. Updates are globally disabled,
    // 2. Client requested no update and server respects it,
    // 3. Client requested that the foward DNS update is delegated to the client
    //    but server neither respects requests for forward update delegation nor
    //    it is configured to send update on its own when client requested
    //    delegation.
    if (!FQDN_ENABLE_UPDATE ||
        (fqdn->getFlag(Option4ClientFqdn::FLAG_N) &&
         !FQDN_OVERRIDE_NO_UPDATE) ||
        (!fqdn->getFlag(Option4ClientFqdn::FLAG_S) &&
         !FQDN_ALLOW_CLIENT_UPDATE && !FQDN_OVERRIDE_CLIENT_UPDATE)) {
        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_N, true);

    // Conditions when S flag is set to indicate that server will perform DNS
    // update on its own:
    // 1. Client requested that server performs DNS update and DNS updates are
    //    globally enabled.
    // 2. Client requested that server delegates forward update to the client
    //    but server doesn't respect requests for delegation and it is
    // configured to perform an update on its own when client requested the
    // delegation.
    } else  if (fqdn->getFlag(Option4ClientFqdn::FLAG_S) ||
                (!fqdn->getFlag(Option4ClientFqdn::FLAG_S) &&
                 !FQDN_ALLOW_CLIENT_UPDATE && FQDN_OVERRIDE_CLIENT_UPDATE)) {
        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_S, true);
    }

    // Server MUST set the O flag if it has overriden the client's setting
    // of S flag.
    if (fqdn->getFlag(Option4ClientFqdn::FLAG_S) !=
        fqdn_resp->getFlag(Option4ClientFqdn::FLAG_S)) {
        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_O, true);
    }

    // If client suppled partial or empty domain-name, server should generate
    // one.
    if (fqdn->getDomainNameType() == Option4ClientFqdn::PARTIAL) {
        std::ostringstream name;
817
        if (fqdn->getDomainName().empty() || FQDN_REPLACE_CLIENT_NAME) {
818 819
            fqdn_resp->setDomainName("", Option4ClientFqdn::PARTIAL);

820 821
        } else {
            name << fqdn->getDomainName();
822 823 824
            name << "." << FQDN_PARTIAL_SUFFIX;
            fqdn_resp->setDomainName(name.str(), Option4ClientFqdn::FULL);

825 826 827
        }

    // Server may be configured to replace a name supplied by a client, even if
828 829 830
    // client supplied fully qualified domain-name. The empty domain-name is
    // is set to indicate that the name must be generated when the new lease
    // is acquired.
831
    } else if(FQDN_REPLACE_CLIENT_NAME) {
832
        fqdn_resp->setDomainName("", Option4ClientFqdn::PARTIAL);
833 834 835 836 837 838 839 840 841 842 843 844 845 846
    }

    // 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.
847
    answer->addOption(fqdn_resp);
848 849 850
}

void
851 852
Dhcpv4Srv::processHostnameOption(const OptionCustomPtr& opt_hostname,
                                 Pkt4Ptr& answer) {
853
    // Do nothing if the DNS updates are disabled.
854 855 856 857 858
    if (!FQDN_ENABLE_UPDATE) {
        return;
    }

    std::string hostname = opt_hostname->readString();
859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875
    unsigned int label_count = OptionDataTypeUtil::getLabelCount(hostname);
    // 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.
    OptionCustomPtr opt_hostname_resp(new OptionCustom(*opt_hostname));

    // 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.

    // If there is only one label, it is a root. We will have to generate
    // the whole domain name for the client.
    if (FQDN_REPLACE_CLIENT_NAME || (label_count < 2)) {
876
        opt_hostname_resp->writeString("");
877 878 879 880 881 882 883 884 885 886
    // 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.
    } else if (label_count == 2) {
        std::ostringstream resp_hostname;
        resp_hostname << hostname << "." << FQDN_PARTIAL_SUFFIX << ".";
        opt_hostname_resp->writeString(resp_hostname.str());
    }

    answer->addOption(opt_hostname_resp);
887 888
}

889 890
void
Dhcpv4Srv::createNameChangeRequests(const Lease4Ptr& lease,
891
                                    const Lease4Ptr& old_lease) {
892 893 894 895 896
    if (!lease) {
        isc_throw(isc::Unexpected,
                  "NULL lease specified when creating NameChangeRequest");
    }

897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915
    // 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.
916
            if  ((lease->hostname_ != old_lease->hostname_) ||
917
                 (lease->fqdn_fwd_ != old_lease->fqdn_fwd_) ||
918 919 920
                 (lease->fqdn_rev_ != old_lease->fqdn_rev_)) {
                queueNameChangeRequest(isc::dhcp_ddns::CHG_REMOVE,
                                       old_lease);
921 922 923 924 925 926 927 928 929 930 931

            // If FQDN data from both leases match, there is no need to update.
            } else if ((lease->hostname_ == old_lease->hostname_) &&
                       (lease->fqdn_fwd_ == old_lease->fqdn_fwd_) &&
                       (lease->fqdn_rev_ == old_lease->fqdn_rev_)) {
                return;
            }

        }
    }

932 933 934 935
    // 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);
936 937
}

938 939
void
Dhcpv4Srv::
940 941 942 943 944 945 946 947
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;
    }
948 949

    // Create the DHCID for the NameChangeRequest.
950 951 952 953 954 955 956 957 958
    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;
    }
959
    // Create NameChangeRequest
960 961 962
    NameChangeRequest ncr(chg_type, lease->fqdn_fwd_, lease->fqdn_rev_,
                          lease->hostname_, lease->addr_.toText(),
                          dhcid, 0, lease->valid_lft_);
963 964 965 966
    // And queue it.
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUEUE_NCR)
        .arg(chg_type == CHG_ADD ? "add" : "remove")
        .arg(ncr.toText());
967 968 969
    name_change_reqs_.push(ncr);
}

970 971 972 973 974 975 976 977 978
void
Dhcpv4Srv::sendNameChangeRequests() {
    while (!name_change_reqs_.empty()) {
        // @todo Once next NameChangeRequest is picked from the queue
        // we should send it to the b10-dhcp_ddns module. Currently we
        // just drop it.
        name_change_reqs_.pop();
    }
}
979

980 981
void
Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998

    // 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).

        // perhaps this should be logged on some higher level? This is most likely
        // configuration bug.
        LOG_ERROR(dhcp4_logger, DHCP4_SUBNET_SELECTION_FAILED)
            .arg(question->getRemoteAddr().toText())
            .arg(serverReceivedPacketName(question->getType()));
999
        answer->setType(DHCPNAK);
1000 1001 1002
        answer->setYiaddr(IOAddress("0.0.0.0"));
        return;
    }
1003

1004 1005 1006
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_SELECTED)
        .arg(subnet->toText());

1007 1008 1009 1010 1011 1012 1013
    // 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
1014

1015
    IOAddress hint = question->getYiaddr();
1016

1017
    HWAddrPtr hwaddr = question->getHWAddr();
1018

1019 1020 1021 1022 1023 1024
    // "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.
1025
    bool fake_allocation = (question->getType() == DHCPDISCOVER);
1026

1027 1028
    CalloutHandlePtr callout_handle = getCalloutHandle(question);

1029 1030 1031
    std::string hostname;
    bool fqdn_fwd = false;
    bool fqdn_rev = false;
1032
    OptionCustomPtr opt_hostname;
1033 1034 1035 1036 1037 1038
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(answer->getOption(DHO_FQDN));
    if (fqdn) {
        hostname = fqdn->getDomainName();
        fqdn_fwd = fqdn->getFlag(Option4ClientFqdn::FLAG_S);
        fqdn_rev = !fqdn->getFlag(Option4ClientFqdn::FLAG_N);
1039
    } else {
1040 1041
        opt_hostname = boost::dynamic_pointer_cast<OptionCustom>
            (answer->getOption(DHO_HOST_NAME));
1042 1043 1044 1045 1046 1047 1048
        if (opt_hostname) {
            hostname = opt_hostname->readString();
            // @todo It could be configurable what sort of updates the server
            // is doing when Hostname option was sent.
            fqdn_fwd = true;
            fqdn_rev = true;
        }
1049 1050
    }

1051 1052 1053 1054
    // 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.
1055 1056
    // @todo pass the actual FQDN data.
    Lease4Ptr old_lease;
1057
    Lease4Ptr lease = alloc_engine_->allocateAddress4(subnet, client_id, hwaddr,
1058 1059
                                                      hint, fqdn_fwd, fqdn_rev,
                                                      hostname,
1060 1061 1062
                                                      fake_allocation,
                                                      callout_handle,
                                                      old_lease);
1063 1064

    if (lease) {
1065 1066
        // We have a lease! Let's set it in the packet and send it back to
        // the client.
1067 1068
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, fake_allocation?
                  DHCP4_LEASE_ADVERT:DHCP4_LEASE_ALLOC)
Tomek Mrugalski's avatar
Tomek Mrugalski committed
1069
            .arg(lease->addr_.toText())
1070
            .arg(client_id?client_id->toText():"(no client-id)")
Tomek Mrugalski's avatar
Tomek Mrugalski committed
1071
            .arg(hwaddr?hwaddr->toText():"(no hwaddr info)");
1072 1073 1074

        answer->setYiaddr(lease->addr_);

1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110
        // If there has been Client FQDN or Hostname option sent, but the
        // hostname is empty, it means that server is responsible for
        // generating the entire hostname for the client. The example of the
        // client's name, generated from the IP address is: host-192-0-2-3.
        if ((fqdn || opt_hostname) && lease->hostname_.empty()) {
            hostname = lease->addr_.toText();
            // Replace dots with hyphens.
            std::replace(hostname.begin(), hostname.end(), '.', '-');
            ostringstream stream;
            // The partial suffix will need to be replaced with the actual
            // domain-name for the client when configuration is implemented.
            stream << "host-" << hostname << "." << FQDN_PARTIAL_SUFFIX << ".";
            lease->hostname_ = stream.str();
            // The operations below are rather safe, but we want to catch
            // any potential exceptions (e.g. invalid lease database backend
            // implementation) and log an error.
            try {
                // The lease update should be safe, because the lease should
                // be already in the database. In most cases the exception
                // would be thrown if the lease was missing.
                LeaseMgrFactory::instance().updateLease4(lease);
                // The name update in the option should be also safe,
                // because the generated name is well formed.
                if (fqdn) {
                    fqdn->setDomainName(lease->hostname_,
                                        Option4ClientFqdn::FULL);
                } else if (opt_hostname) {
                    opt_hostname->writeString(lease->hostname_);
                }

            } catch (const Exception& ex) {
                LOG_ERROR(dhcp4_logger, DHCP4_NAME_GEN_UPDATE_FAIL)
                    .arg(ex.what());
            }
        }

1111 1112 1113 1114 1115 1116
        // IP Address Lease time (type 51)
        opt = OptionPtr(new Option(Option::V4, DHO_DHCP_LEASE_TIME));
        opt->setUint32(lease->valid_lft_);
        answer->addOption(opt);

        // Router (type 3)
1117 1118 1119 1120 1121
        Subnet::OptionDescriptor opt_routers =
            subnet->getOptionDescriptor("dhcp4", DHO_ROUTERS);
        if (opt_routers.option) {
            answer->addOption(opt_routers.option);
        }
1122 1123 1124 1125 1126 1127 1128

        // Subnet mask (type 1)
        answer->addOption(getNetmaskOption(subnet));

        // @todo: send renew timer option (T1, option 58)
        // @todo: send rebind timer option (T2, option 59)

1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143
        // @todo Currently the NameChangeRequests are always generated if
        // real (not fake) allocation is being performed. Should we have
        // control switch to enable/disable NameChangeRequest creation?
        // Perhaps we need a way to detect whether the b10-dhcp-ddns module
        // is up an running?
        if (!fake_allocation) {
            try {
                createNameChangeRequests(lease, old_lease);
            } catch (const Exception& ex) {
                LOG_ERROR(dhcp4_logger, DHCP4_NCR_CREATION_FAILED)
                    .arg(ex.what());
            }

        }

1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154
    } else {
        // Allocation engine did not allocate a lease. The engine logged
        // cause of that failure. The only thing left is to insert
        // status code to pass the sad news to the client.

        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, fake_allocation?
                  DHCP4_LEASE_ADVERT_FAIL:DHCP4_LEASE_ALLOC_FAIL)
            .arg(client_id?client_id->toText():"(no client-id)")
            .arg(hwaddr?hwaddr->toText():"(no hwaddr info)")
            .arg(hint.toText());

1155
        answer->setType(DHCPNAK);
1156
        answer->setYiaddr(IOAddress("0.0.0.0"));
1157 1158 1159

        answer->delOption(DHO_FQDN);
        answer->delOption(DHO_HOST_NAME);
1160 1161 1162
    }
}

1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
void
Dhcpv4Srv::adjustRemoteAddr(const Pkt4Ptr& question, Pkt4Ptr& msg) {
    // Let's create static objects representing zeroed and broadcast
    // addresses. We will use them further in this function to test
    // other addresses against them. Since they are static, they will
    // be created only once.
    static const IOAddress zero_addr("0.0.0.0");
    static const IOAddress bcast_addr("255.255.255.255");

    // If received relayed message, server responds to the relay address.
    if (question->getGiaddr() != zero_addr) {
        msg->setRemoteAddr(question->getGiaddr());

    // If giaddr is 0 but client set ciaddr, server should unicast the
    // response to ciaddr.
    } else if (question->getCiaddr() != zero_addr) {
        msg->setRemoteAddr(question->getCiaddr());

    // We can't unicast the response to the client when sending NAK,