dhcp4_srv.cc 90.6 KB
Newer Older
1
// Copyright (C) 2011-2015 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 <config.h>
16
#include <asiolink/io_address.h>
17
#include <dhcp/dhcp4.h>
18 19
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
20
#include <dhcp/iface_mgr.h>
21
#include <dhcp/option4_addrlst.h>
22
#include <dhcp/option_int.h>
23
#include <dhcp/option_int_array.h>
24
#include <dhcp/option_vendor.h>
25
#include <dhcp/option_string.h>
26
#include <dhcp/pkt4.h>
27
#include <dhcp/docsis3_option_defs.h>
28 29
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
30 31
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
32
#include <dhcpsrv/cfgmgr.h>
33
#include <dhcpsrv/cfg_subnets4.h>
34 35 36
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
#include <dhcpsrv/subnet.h>
37
#include <dhcpsrv/subnet_selector.h>
38
#include <dhcpsrv/utils.h>
39
#include <dhcpsrv/utils.h>
40
#include <hooks/callout_handle.h>
41
#include <hooks/hooks_log.h>
42
#include <hooks/hooks_manager.h>
43
#include <util/strutil.h>
44
#include <stats/stats_mgr.h>
45

46
#include <asio.hpp>
47
#include <boost/bind.hpp>
48
#include <boost/foreach.hpp>
49
#include <boost/shared_ptr.hpp>
50 51 52

#include <iomanip>

53 54
using namespace isc;
using namespace isc::asiolink;
55
using namespace isc::dhcp;
56
using namespace isc::dhcp_ddns;
57
using namespace isc::hooks;
58 59
using namespace isc::log;
using namespace std;
60

61
/// Structure that holds registered hook indexes
62 63
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
64 65
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
66
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
67
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
68
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
69

70 71 72
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
73 74 75
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
76 77
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
78 79 80 81 82 83 84
    }
};

// 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.
85
Dhcp4Hooks Hooks;
86

87 88 89
namespace isc {
namespace dhcp {

90
Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
91 92
                               const Pkt4Ptr& query,
                               const Subnet4Ptr& subnet)
93 94
    : alloc_engine_(alloc_engine), query_(query), resp_(),
      context_(new AllocEngine::ClientContext4()) {
95

96 97 98 99 100 101 102 103
    if (!alloc_engine_) {
        isc_throw(BadValue, "alloc_engine value must not be NULL"
                  " when creating an instance of the Dhcpv4Exchange");
    }

    if (!query_) {
        isc_throw(BadValue, "query value must not be NULL when"
                  " creating an instance of the Dhcpv4Exchange");
104 105
    }

106 107 108
    // Create response message.
    initResponse();
    // Select subnet for the query message.
109
    context_->subnet_ = subnet;
110
    // Hardware address.
111
    context_->hwaddr_ = query->getHWAddr();
112 113 114
    // Client Identifier
    OptionPtr opt_clientid = query->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (opt_clientid) {
115
        context_->clientid_.reset(new ClientId(opt_clientid->getData()));
116 117
    }
    // Check for static reservations.
118
    alloc_engine->findReservation(*context_);
119 120
};

121
void
122
Dhcpv4Exchange::initResponse() {
123 124 125 126 127 128 129 130 131 132 133 134
    uint8_t resp_type = 0;
    switch (getQuery()->getType()) {
    case DHCPDISCOVER:
        resp_type = DHCPOFFER;
        break;
    case DHCPREQUEST:
    case DHCPINFORM:
        resp_type = DHCPACK;
        break;
    default:
        ;
    }
135
    // Only create a response if one is required.
136 137
    if (resp_type > 0) {
        resp_.reset(new Pkt4(resp_type, getQuery()->getTransid()));
138 139 140 141 142 143 144 145 146
        copyDefaultFields();
    }
}

void
Dhcpv4Exchange::copyDefaultFields() {
    resp_->setIface(query_->getIface());
    resp_->setIndex(query_->getIndex());

147 148
    // explicitly set this to 0
    resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS());
149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187
    // ciaddr is always 0, except for the Renew/Rebind state when it may
    // be set to the ciaddr sent by the client.
    resp_->setCiaddr(IOAddress::IPV4_ZERO_ADDRESS());
    resp_->setHops(query_->getHops());

    // copy MAC address
    resp_->setHWAddr(query_->getHWAddr());

    // relay address
    resp_->setGiaddr(query_->getGiaddr());

    // Let's copy client-id to response. See RFC6842.
    // It is possible to disable RFC6842 to keep backward compatibility
    bool echo = CfgMgr::instance().echoClientId();
    OptionPtr client_id = query_->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (client_id && echo) {
        resp_->addOption(client_id);
    }

    // If src/dest HW addresses are used by the packet filtering class
    // 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.
    HWAddrPtr src_hw_addr = query_->getLocalHWAddr();
    if (src_hw_addr) {
        resp_->setLocalHWAddr(src_hw_addr);
    }
    HWAddrPtr dst_hw_addr = query_->getRemoteHWAddr();
    if (dst_hw_addr) {
        resp_->setRemoteHWAddr(dst_hw_addr);
    }

    // If this packet is relayed, we want to copy Relay Agent Info option
    OptionPtr rai = query_->getOption(DHO_DHCP_AGENT_OPTIONS);
    if (rai) {
        resp_->addOption(rai);
188 189 190
    }
}

191 192
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

193
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast,
194
                     const bool direct_response_desired)
195 196 197
    : shutdown_(true), alloc_engine_(), port_(port),
      use_bcast_(use_bcast), hook_index_pkt4_receive_(-1),
      hook_index_subnet4_select_(-1), hook_index_pkt4_send_(-1) {
198

199
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
200
    try {
201 202 203
        // Port 0 is used for testing purposes where we don't open broadcast
        // capable sockets. So, set the packet filter handling direct traffic
        // only if we are in non-test mode.
204
        if (port) {
205 206 207 208 209 210 211 212
            // 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);
213
        }
214

215
        // Instantiate allocation engine
216 217
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100,
                                            false /* false = IPv4 */));
218

219 220 221 222 223 224 225
        // 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

226
    } catch (const std::exception &e) {
227
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
228 229 230
        shutdown_ = true;
        return;
    }
231

Tomek Mrugalski's avatar
Tomek Mrugalski committed
232
    shutdown_ = false;
233 234 235
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
236
    IfaceMgr::instance().closeSockets();
237 238
}

239 240
void
Dhcpv4Srv::shutdown() {
241
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
242 243 244
    shutdown_ = true;
}

245
isc::dhcp::Subnet4Ptr
246
Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
247 248 249 250 251 252 253 254 255 256 257 258 259 260 261

    Subnet4Ptr subnet;

    SubnetSelector selector;
    selector.ciaddr_ = query->getCiaddr();
    selector.giaddr_ = query->getGiaddr();
    selector.local_address_ = query->getLocalAddr();
    selector.remote_address_ = query->getRemoteAddr();
    selector.client_classes_ = query->classes_;
    selector.iface_name_ = query->getIface();

    CfgMgr& cfgmgr = CfgMgr::instance();
    subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet(selector);

    // Let's execute all callouts registered for subnet4_select
262
    if (HooksManager::calloutsPresent(hook_index_subnet4_select_)) {
263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282
        CalloutHandlePtr callout_handle = getCalloutHandle(query);

        // We're reusing callout_handle from previous calls
        callout_handle->deleteAllArguments();

        // Set new arguments
        callout_handle->setArgument("query4", query);
        callout_handle->setArgument("subnet4", subnet);
        callout_handle->setArgument("subnet4collection",
                                    cfgmgr.getCurrentCfg()->
                                    getCfgSubnets4()->getAll());

        // Call user (and server-side) callouts
        HooksManager::callCallouts(hook_index_subnet4_select_,
                                   *callout_handle);

        // Callouts decided to skip this step. This means that no subnet
        // will be selected. Packet processing will continue, but it will
        // be severely limited (i.e. only global options will be assigned)
        if (callout_handle->getSkip()) {
283
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
284 285
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
286 287 288 289 290 291 292
            return (Subnet4Ptr());
        }

        // Use whatever subnet was specified by the callout
        callout_handle->getArgument("subnet4", subnet);
    }

293 294
    if (subnet) {
        // Log at higher debug level that subnet has been found.
295
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
296 297 298 299 300 301 302 303 304 305 306 307 308 309
            .arg(query->getLabel())
            .arg(subnet->getID());
        // Log detailed information about the selected subnet at the
        // lower debug level.
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_DATA)
            .arg(query->getLabel())
            .arg(subnet->toText());

    } else {
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL,
                  DHCP4_SUBNET_SELECTION_FAILED)
            .arg(query->getLabel());
    }

310
    return (subnet);
311 312
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
313 314
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
315 316 317
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
318 319
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
320 321 322
    IfaceMgr::instance().send(packet);
}

323 324
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
325
    while (!shutdown_) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
326
        // client's message and server's response
327
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
328
        Pkt4Ptr rsp;
329

330
        try {
331 332 333 334 335 336 337 338 339 340
            // The lease database backend may install some timers for which
            // the handlers need to be executed periodically. Retrieve the
            // maximum interval at which the handlers must be executed from
            // the lease manager.
            uint32_t timeout = LeaseMgrFactory::instance().getIOServiceExecInterval();
            // If the returned value is zero it means that there are no
            // timers installed, so use a default value.
            if (timeout == 0) {
                timeout = 1000;
            }
341
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT).arg(timeout);
342
            query = receivePacket(timeout);
343

344 345 346 347 348 349 350
            // Log if packet has arrived. We can't log the detailed information
            // about the DHCP message because it hasn't been unpacked/parsed
            // yet, and it can't be parsed at this point because hooks will
            // have to process it first. The only information available at this
            // point are: the interface, source address and destination addresses
            // and ports.
            if (query) {
351
                LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_BUFFER_RECEIVED)
352 353 354 355 356 357 358 359 360 361 362
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getRemotePort())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getLocalPort())
                    .arg(query->getIface());

            } else {
                LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_TIMEOUT)
                    .arg(timeout);
            }

363 364 365 366 367 368
        } catch (const SignalInterruptOnSelect) {
            // Packet reception interrupted because a signal has been received.
            // This is not an error because we might have received a SIGTERM,
            // SIGINT or SIGHUP which are handled by the server. For signals
            // that are not handled by the server we rely on the default
            // behavior of the system, but there is nothing we should log here.
369 370
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_SIGNAL)
                .arg(signal_set_->getNext());
371
        } catch (const std::exception& e) {
372
            // Log all other errors.
373
            LOG_ERROR(packet_logger, DHCP4_BUFFER_RECEIVE_FAIL).arg(e.what());
374 375
        }

376 377 378
        // 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
Francis Dupont's avatar
Francis Dupont committed
379 380 381 382 383 384 385
        // of select() (select is invoked by receivePacket()). 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.
386 387
        handleSignal();

388 389
        // Execute ready timers for the lease database, e.g. Lease File Cleanup.
        try {
390
            LeaseMgrFactory::instance().getIOService()->poll();
391 392 393 394 395 396

        } catch (const std::exception& ex) {
            LOG_WARN(dhcp4_logger, DHCP4_LEASE_DATABASE_TIMERS_EXEC_FAIL)
                .arg(ex.what());
        }

397
        // Timeout may be reached or signal received, which breaks select()
398 399
        // with no reception occurred. No need to log anything here because
        // we have logged right after the call to receivePacket().
400 401 402 403
        if (!query) {
            continue;
        }

404 405 406 407 408 409
        // Log reception of the packet. We need to increase it early, as any
        // failures in unpacking will cause the packet to be dropped. We
        // will increase type specific packets further down the road.
        // See processStatsReceived().
        isc::stats::StatsMgr::instance().addValue("pkt4-received", 1ul);

410 411 412 413 414 415 416 417 418
        // 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));

419 420 421
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
422
        // data; execute callouts registered for buffer4_receive.
423
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
424 425 426 427 428 429 430 431 432
            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
433 434
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
435 436 437 438 439 440

            // 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()) {
441
                LOG_DEBUG(hooks_logger, DBG_DHCP4_DETAIL, DHCP4_HOOK_BUFFER_RCVD_SKIP)
442 443 444
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
445 446 447 448 449 450 451 452 453
                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
454
            try {
455 456 457 458
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_UNPACK)
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
Tomek Mrugalski's avatar
Tomek Mrugalski committed
459 460
                query->unpack();
            } catch (const std::exception& e) {
461
                // Failed to parse the packet.
462 463
                LOG_DEBUG(bad_packet_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_DROP_0001)
464 465 466
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface())
467
                    .arg(e.what());
468 469 470 471

                // Increase the statistics of parse failues and dropped packets.
                isc::stats::StatsMgr::instance().addValue("pkt4-parse-failed", 1ul);
                isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop", 1ul);
472 473
                continue;
            }
474
        }
475

476 477 478
        // Update statistics accordingly for received packet.
        processStatsReceived(query);

Tomek Mrugalski's avatar
Tomek Mrugalski committed
479 480 481
        // 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.
482 483
        classifyPacket(query);

484 485 486
        // 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)) {
487
            // Increase the statistic of dropped packets.
488
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop", 1ul);
489
            continue;
490
        }
491

492
        // We have sanity checked (in accept() that the Message Type option
493 494
        // exists, so we can safely get it here.
        int type = query->getType();
495
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_PACKET_RECEIVED)
496
            .arg(query->getLabel())
497
            .arg(query->getName())
498
            .arg(type)
499 500
            .arg(query->getRemoteAddr())
            .arg(query->getLocalAddr())
501
            .arg(query->getIface());
502 503
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
            .arg(query->getLabel())
504 505
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
506
        // Let's execute all callouts registered for pkt4_receive
507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523
        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()) {
524
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP)
525
                    .arg(query->getLabel());
526 527
                continue;
            }
528

529 530
            callout_handle->getArgument("query4", query);
        }
531

532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553
        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:
554
                rsp = processInform(query);
555 556 557 558 559 560 561
                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.
                ;
562
            }
563 564
        } catch (const isc::Exception& e) {

565 566 567 568 569 570
            // 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 Kea 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.)
571 572 573 574
            LOG_DEBUG(bad_packet_logger, DBG_DHCP4_BASIC,
                      DHCP4_PACKET_DROP_0007)
                .arg(query->getLabel())
                .arg(e.what());
575 576 577

            // Increase the statistic of dropped packets.
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop", 1ul);
578
        }
579

580 581 582
        if (!rsp) {
            continue;
        }
583

584

585 586
        // Specifies if server should do the packing
        bool skip_pack = false;
587

Tomek Mrugalski's avatar
Tomek Mrugalski committed
588
        // Execute all callouts registered for pkt4_send
589 590
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
591

592 593
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
594

595 596
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
597

598 599
            // Set our response
            callout_handle->setArgument("response4", rsp);
600

601 602 603
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
604

605 606 607 608
            // 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()) {
609
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP)
610
                    .arg(query->getLabel());
611 612 613 614 615 616
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
617 618
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_PACK)
                    .arg(rsp->getLabel());
619 620
                rsp->pack();
            } catch (const std::exception& e) {
621 622
                LOG_ERROR(options_logger, DHCP4_PACKET_PACK_FAIL)
                    .arg(rsp->getLabel())
623 624 625 626 627 628 629 630
                    .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
631
            // Let's execute all callouts registered for buffer4_send
632
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
633
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
634

635 636
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
637

638 639
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
640

641
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
642 643
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
644

645 646 647 648
                // 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()) {
649
                    LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
650 651
                              DHCP4_HOOK_BUFFER_SEND_SKIP)
                        .arg(rsp->getLabel());
652
                    continue;
653
                }
654 655

                callout_handle->getArgument("response4", rsp);
656
            }
657

658
            LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND)
659
                .arg(rsp->getLabel())
660
                .arg(rsp->getName())
661 662 663 664 665 666
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->getLocalAddr())
                .arg(rsp->getLocalPort())
                .arg(rsp->getRemoteAddr())
                .arg(rsp->getRemotePort())
                .arg(rsp->getIface());
667 668

            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA,
669
                      DHCP4_RESPONSE_DATA)
670 671 672 673
                .arg(rsp->getLabel())
                .arg(rsp->getName())
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->toText());
674
            sendPacket(rsp);
675 676 677 678

            // Update statistics accordingly for sent packet.
            processStatsSent(rsp);

679
        } catch (const std::exception& e) {
680 681
            LOG_ERROR(packet_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(rsp->getLabel())
682
                .arg(e.what());
683
        }
684 685 686 687 688
    }

    return (true);
}

689
string
690
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706
    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());
707 708
}

709
isc::dhcp_ddns::D2Dhcid
710 711 712 713 714 715 716 717 718
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");

719 720
    }

721 722 723 724 725 726 727 728 729
    // 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);
730

731 732 733
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
734 735

    }
736 737 738

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
739
    try {
740 741 742 743
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
744
            return (D2Dhcid(lease->hwaddr_, fqdn_wire));
745
        }
746
    } catch (const Exception& ex) {
747 748
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
749

750
    }
751 752 753

}

754
void
755
Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) {
756 757 758
    // 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.
759 760
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
761 762 763
    OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                           ex.getResponse()->getLocalAddr()));
    ex.getResponse()->addOption(opt_srvid);
764 765
}

766
void
767
Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) {
768 769
    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
770
    Subnet4Ptr subnet = ex.getContext()->subnet_;
771 772 773 774 775 776 777
    // 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;
    }
778

779 780
    Pkt4Ptr query = ex.getQuery();

781 782 783
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
784
        OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
785 786 787 788 789
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
790

791 792
    Pkt4Ptr resp = ex.getResponse();

793 794 795 796 797 798
    // 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) {
799
        if (!resp->getOption(*opt)) {
800
            OptionDescriptor desc = subnet->getCfgOption()->get("dhcp4", *opt);
801
            if (desc.option_) {
802
                resp->addOption(desc.option_);
803
            }
804 805
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
806
}
807

808
void
809
Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) {
810
    // Get the configured subnet suitable for the incoming packet.
811
    Subnet4Ptr subnet = ex.getContext()->subnet_;
812 813 814 815 816 817 818 819 820 821
    // 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
822 823
    boost::shared_ptr<OptionVendor> vendor_req = boost::dynamic_pointer_cast<
        OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS));
824 825 826 827 828 829 830
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
831 832
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
833 834
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
835 836 837 838 839 840 841 842 843 844

    // 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;
845
    const std::vector<uint8_t>& requested_opts = oro->getValues();
846

Tomek Mrugalski's avatar
Tomek Mrugalski committed
847
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
848
         code != requested_opts.end(); ++code) {
849
        if  (!vendor_rsp->getOption(*code)) {
850 851
            OptionDescriptor desc = subnet->getCfgOption()->get(vendor_id,
                                                                *code);
852 853
            if (desc.option_) {
                vendor_rsp->addOption(desc.option_);
854 855
                added = true;
            }
856 857
        }

858
        if (added) {
859
            ex.getResponse()->addOption(vendor_rsp);
860 861
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
862
}
863

864

865
void
866
Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) {
867 868 869 870 871 872
    // 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 };
873

874 875 876 877
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
878
    Subnet4Ptr subnet = ex.getContext()->subnet_;
879 880 881 882
    if (!subnet) {
        return;
    }

883 884
    Pkt4Ptr resp = ex.getResponse();

885 886 887
    // 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) {
888
        OptionPtr opt = resp->getOption(required_options[i]);
889 890
        if (!opt) {
            // Check whether option has been configured.
891 892
            OptionDescriptor desc = subnet->getCfgOption()->
                get("dhcp4", required_options[i]);
893
            if (desc.option_) {
894
                resp->addOption(desc.option_);
895 896 897
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
898
}
899

900
void
901
Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) {
902 903 904
    // 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.
905
    try {
906
        Pkt4Ptr resp = ex.getResponse();
907
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
908
            (ex.getQuery()->getOption(DHO_FQDN));
909
        if (fqdn) {
910
            LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_FQDN_PROCESS)
911
                .arg(ex.getQuery()->getLabel());
912
            processClientFqdnOption(ex);
913 914

        } else {
915
            OptionStringPtr hostname = boost::dynamic_pointer_cast<OptionString>
916
                (ex.getQuery()->getOption(DHO_HOST_NAME));
917
            if (hostname) {
918
                LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_HOSTNAME_PROCESS)
919
                    .arg(ex.getQuery()->getLabel());
920
                processHostnameOption(ex);
921 922
            }
        }
923
    } catch (const Exception& e) {
924 925 926 927 928 929 930 931
        // 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.
932
        LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
933 934
            .arg(ex.getQuery()->getLabel())
            .arg(e.what());
935 936 937 938
    }
}

void
939
Dhcpv4Srv::processClientFqdnOption(Dhcpv4Exchange& ex) {
940 941 942 943
    // Obtain the FQDN option from the client's message.
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(ex.getQuery()->getOption(DHO_FQDN));

944
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_FQDN_DATA)
945 946 947
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn->toText());

948 949 950 951
    // Create the DHCPv4 Client FQDN Option to be included in the server's
    // response to a client.
    Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));

952 953 954 955
    // 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);
956

957 958 959
    // Carry over the client's E flag.
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E,
                       fqdn->getFlag(Option4ClientFqdn::FLAG_E));
960

961
    if (ex.getContext()->host_ && !ex.getContext()->host_->getHostname().empty()) {
962 963 964
        D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
        fqdn_resp->setDomainName(d2_mgr.qualifyName(ex.getContext()->host_->getHostname(),
                                                    true), Option4ClientFqdn::FULL);
965

966 967 968 969 970
    } else {
        // 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);
    }
971 972 973 974 975 976 977 978 979