dhcp4_srv.cc 92.1 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 <log/logger.h>
#include <cryptolink/cryptolink.h>
47
#include <cfgrpt/config_report.h>
48

49
#include <asio.hpp>
50
#include <boost/bind.hpp>
51
#include <boost/foreach.hpp>
52
#include <boost/shared_ptr.hpp>
53 54 55

#include <iomanip>

56 57
using namespace isc;
using namespace isc::asiolink;
58
using namespace isc::cryptolink;
59
using namespace isc::dhcp;
60
using namespace isc::dhcp_ddns;
61
using namespace isc::hooks;
62 63
using namespace isc::log;
using namespace std;
64

65
/// Structure that holds registered hook indexes
66 67
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
68 69
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
70
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
71
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
72
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
73

74 75 76
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
77 78 79
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
80 81
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
82 83 84 85 86 87 88
    }
};

// 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.
89
Dhcp4Hooks Hooks;
90

91 92 93
namespace isc {
namespace dhcp {

94
Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
95 96
                               const Pkt4Ptr& query,
                               const Subnet4Ptr& subnet)
97 98
    : alloc_engine_(alloc_engine), query_(query), resp_(),
      context_(new AllocEngine::ClientContext4()) {
99

100 101 102 103 104 105 106 107
    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");
108 109
    }

110 111 112
    // Create response message.
    initResponse();
    // Select subnet for the query message.
113
    context_->subnet_ = subnet;
114
    // Hardware address.
115
    context_->hwaddr_ = query->getHWAddr();
116

117
    // Set client identifier if the match-client-id flag is enabled (default).
118 119 120
    // If the subnet wasn't found it doesn't matter because we will not be
    // able to allocate a lease anyway so this context will not be used.
    if (subnet) {
121
        if (subnet->getMatchClientId()) {
122 123 124 125 126 127 128 129 130 131
            OptionPtr opt_clientid = query->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
            if (opt_clientid) {
                context_->clientid_.reset(new ClientId(opt_clientid->getData()));
            }
        } else {
            /// @todo When merging with #3806 use different logger.
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENTID_IGNORED_FOR_LEASES)
                .arg(query->getLabel())
                .arg(subnet->getID());
        }
132 133
    }
    // Check for static reservations.
134
    alloc_engine->findReservation(*context_);
135 136
};

137
void
138
Dhcpv4Exchange::initResponse() {
139 140 141 142 143 144 145 146 147 148 149 150
    uint8_t resp_type = 0;
    switch (getQuery()->getType()) {
    case DHCPDISCOVER:
        resp_type = DHCPOFFER;
        break;
    case DHCPREQUEST:
    case DHCPINFORM:
        resp_type = DHCPACK;
        break;
    default:
        ;
    }
151
    // Only create a response if one is required.
152 153
    if (resp_type > 0) {
        resp_.reset(new Pkt4(resp_type, getQuery()->getTransid()));
154 155 156 157 158 159 160 161 162
        copyDefaultFields();
    }
}

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

163 164
    // explicitly set this to 0
    resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS());
165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203
    // 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);
204 205 206
    }
}

207 208
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

209
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast,
210
                     const bool direct_response_desired)
211 212 213
    : 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) {
214

215
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
216
    try {
217 218 219
        // 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.
220
        if (port) {
221 222 223 224 225 226 227 228
            // 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);
229
        }
230

231
        // Instantiate allocation engine
232 233
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100,
                                            false /* false = IPv4 */));
234

235 236 237 238 239 240 241
        // 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

242
    } catch (const std::exception &e) {
243
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
244 245 246
        shutdown_ = true;
        return;
    }
247

Tomek Mrugalski's avatar
Tomek Mrugalski committed
248
    shutdown_ = false;
249 250 251
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
252
    IfaceMgr::instance().closeSockets();
253 254
}

255 256
void
Dhcpv4Srv::shutdown() {
257
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
258 259 260
    shutdown_ = true;
}

261
isc::dhcp::Subnet4Ptr
262
Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
263 264 265 266 267 268 269 270 271 272 273 274 275 276 277

    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
278
    if (HooksManager::calloutsPresent(hook_index_subnet4_select_)) {
279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298
        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()) {
299
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
300 301
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
302 303 304 305 306 307 308
            return (Subnet4Ptr());
        }

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

309 310
    if (subnet) {
        // Log at higher debug level that subnet has been found.
311
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
312 313 314 315 316 317 318 319 320 321 322 323 324 325
            .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());
    }

326
    return (subnet);
327 328
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
329 330
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
331 332 333
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
334 335
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
336 337 338
    IfaceMgr::instance().send(packet);
}

339 340
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
341
    while (!shutdown_) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
342
        // client's message and server's response
343
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
344
        Pkt4Ptr rsp;
345

346
        try {
347 348 349 350 351 352 353 354 355 356
            // 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;
            }
357
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT).arg(timeout);
358
            query = receivePacket(timeout);
359

360 361 362 363 364 365 366
            // 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) {
367
                LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_BUFFER_RECEIVED)
368 369 370 371 372 373 374
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getRemotePort())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getLocalPort())
                    .arg(query->getIface());

            } else {
375
                LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_INTERRUPTED)
376 377 378
                    .arg(timeout);
            }

379 380 381 382 383
        } 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
384
            // behavior of the system.
385 386
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_SIGNAL)
                .arg(signal_set_->getNext());
387
        } catch (const std::exception& e) {
388
            // Log all other errors.
389
            LOG_ERROR(packet_logger, DHCP4_BUFFER_RECEIVE_FAIL).arg(e.what());
390 391
        }

392 393 394
        // 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
395 396 397 398 399 400 401
        // 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.
402 403
        handleSignal();

404 405
        // Execute ready timers for the lease database, e.g. Lease File Cleanup.
        try {
406
            LeaseMgrFactory::instance().getIOService()->poll();
407 408 409 410 411 412

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

413
        // Timeout may be reached or signal received, which breaks select()
414 415
        // with no reception occurred. No need to log anything here because
        // we have logged right after the call to receivePacket().
416 417 418 419
        if (!query) {
            continue;
        }

420 421 422 423
        // 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().
Tomek Mrugalski's avatar
Tomek Mrugalski committed
424 425
        isc::stats::StatsMgr::instance().addValue("pkt4-received",
                                                  static_cast<uint64_t>(1));
426

427 428 429 430 431 432 433 434 435
        // 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));

436 437 438
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
439
        // data; execute callouts registered for buffer4_receive.
440
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
441 442 443 444 445 446 447 448 449
            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
450 451
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
452 453 454 455 456 457

            // 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()) {
458
                LOG_DEBUG(hooks_logger, DBG_DHCP4_DETAIL, DHCP4_HOOK_BUFFER_RCVD_SKIP)
459 460 461
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
462 463 464 465 466 467 468 469 470
                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
471
            try {
472 473 474 475
                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
476 477
                query->unpack();
            } catch (const std::exception& e) {
478
                // Failed to parse the packet.
479 480
                LOG_DEBUG(bad_packet_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_DROP_0001)
481 482 483
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface())
484
                    .arg(e.what());
485 486

                // Increase the statistics of parse failues and dropped packets.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
487 488 489 490
                isc::stats::StatsMgr::instance().addValue("pkt4-parse-failed",
                                                          static_cast<uint64_t>(1));
                isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
                                                          static_cast<uint64_t>(1));
491 492
                continue;
            }
493
        }
494

495 496 497
        // Update statistics accordingly for received packet.
        processStatsReceived(query);

Tomek Mrugalski's avatar
Tomek Mrugalski committed
498 499 500
        // 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.
501 502
        classifyPacket(query);

503 504 505
        // 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)) {
506
            // Increase the statistic of dropped packets.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
507 508
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
                                                      static_cast<uint64_t>(1));
509
            continue;
510
        }
511

512
        // We have sanity checked (in accept() that the Message Type option
513 514
        // exists, so we can safely get it here.
        int type = query->getType();
515
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_PACKET_RECEIVED)
516
            .arg(query->getLabel())
517
            .arg(query->getName())
518
            .arg(type)
519 520
            .arg(query->getRemoteAddr())
            .arg(query->getLocalAddr())
521
            .arg(query->getIface());
522 523
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
            .arg(query->getLabel())
524 525
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
526
        // Let's execute all callouts registered for pkt4_receive
527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543
        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()) {
544
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP)
545
                    .arg(query->getLabel());
546 547
                continue;
            }
548

549 550
            callout_handle->getArgument("query4", query);
        }
551

552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573
        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:
574
                rsp = processInform(query);
575 576 577 578 579 580 581
                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.
                ;
582
            }
583 584
        } catch (const isc::Exception& e) {

585 586 587 588 589 590
            // 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.)
591 592 593 594
            LOG_DEBUG(bad_packet_logger, DBG_DHCP4_BASIC,
                      DHCP4_PACKET_DROP_0007)
                .arg(query->getLabel())
                .arg(e.what());
595 596

            // Increase the statistic of dropped packets.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
597 598
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
                                                      static_cast<uint64_t>(1));
599
        }
600

601 602 603
        if (!rsp) {
            continue;
        }
604

605

606 607
        // Specifies if server should do the packing
        bool skip_pack = false;
608

Tomek Mrugalski's avatar
Tomek Mrugalski committed
609
        // Execute all callouts registered for pkt4_send
610 611
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
612

613 614
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
615

616 617
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
618

619 620
            // Set our response
            callout_handle->setArgument("response4", rsp);
621

622 623 624
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
625

626 627 628 629
            // 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()) {
630
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP)
631
                    .arg(query->getLabel());
632 633 634 635 636 637
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
638 639
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_PACK)
                    .arg(rsp->getLabel());
640 641
                rsp->pack();
            } catch (const std::exception& e) {
642 643
                LOG_ERROR(options_logger, DHCP4_PACKET_PACK_FAIL)
                    .arg(rsp->getLabel())
644 645 646 647 648 649 650 651
                    .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
652
            // Let's execute all callouts registered for buffer4_send
653
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
654
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
655

656 657
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
658

659 660
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
661

662
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
663 664
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
665

666 667 668 669
                // 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()) {
670
                    LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
671 672
                              DHCP4_HOOK_BUFFER_SEND_SKIP)
                        .arg(rsp->getLabel());
673
                    continue;
674
                }
675 676

                callout_handle->getArgument("response4", rsp);
677
            }
678

679
            LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND)
680
                .arg(rsp->getLabel())
681
                .arg(rsp->getName())
682 683 684 685 686 687
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->getLocalAddr())
                .arg(rsp->getLocalPort())
                .arg(rsp->getRemoteAddr())
                .arg(rsp->getRemotePort())
                .arg(rsp->getIface());
688 689

            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA,
690
                      DHCP4_RESPONSE_DATA)
691 692 693 694
                .arg(rsp->getLabel())
                .arg(rsp->getName())
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->toText());
695
            sendPacket(rsp);
696 697 698 699

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

700
        } catch (const std::exception& e) {
701 702
            LOG_ERROR(packet_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(rsp->getLabel())
703
                .arg(e.what());
704
        }
705 706 707 708 709
    }

    return (true);
}

710
string
711
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
    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());
728 729
}

730
isc::dhcp_ddns::D2Dhcid
731 732 733 734 735 736 737 738 739
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");

740 741
    }

742 743 744 745 746 747 748 749 750
    // 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);
751

752 753 754
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
755 756

    }
757 758 759

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
760
    try {
761 762 763 764
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
765
            return (D2Dhcid(lease->hwaddr_, fqdn_wire));
766
        }
767
    } catch (const Exception& ex) {
768 769
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
770

771
    }
772 773 774

}

775
void
776
Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) {
777 778 779
    // 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.
780 781
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
782 783 784
    OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                           ex.getResponse()->getLocalAddr()));
    ex.getResponse()->addOption(opt_srvid);
785 786
}

787
void
788
Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) {
789 790
    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
791
    Subnet4Ptr subnet = ex.getContext()->subnet_;
792 793 794 795 796 797 798
    // 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;
    }
799

800 801
    Pkt4Ptr query = ex.getQuery();

802 803 804
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
805
        OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
806 807 808 809 810
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
811

812 813
    Pkt4Ptr resp = ex.getResponse();

814 815 816 817 818 819
    // 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) {
820
        if (!resp->getOption(*opt)) {
821
            OptionDescriptor desc = subnet->getCfgOption()->get("dhcp4", *opt);
822
            if (desc.option_) {
823
                resp->addOption(desc.option_);
824
            }
825 826
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
827
}
828

829
void
830
Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) {
831
    // Get the configured subnet suitable for the incoming packet.
832
    Subnet4Ptr subnet = ex.getContext()->subnet_;
833 834 835 836 837 838 839 840 841 842
    // 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
843 844
    boost::shared_ptr<OptionVendor> vendor_req = boost::dynamic_pointer_cast<
        OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS));
845 846 847 848 849 850 851
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
852 853
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
854 855
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
856 857 858 859 860 861 862 863 864 865

    // 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;
866
    const std::vector<uint8_t>& requested_opts = oro->getValues();
867

Tomek Mrugalski's avatar
Tomek Mrugalski committed
868
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
869
         code != requested_opts.end(); ++code) {
870
        if  (!vendor_rsp->getOption(*code)) {
871 872
            OptionDescriptor desc = subnet->getCfgOption()->get(vendor_id,
                                                                *code);
873 874
            if (desc.option_) {
                vendor_rsp->addOption(desc.option_);
875 876
                added = true;
            }
877 878
        }

879
        if (added) {
880
            ex.getResponse()->addOption(vendor_rsp);
881 882
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
883
}
884

885

886
void
887
Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) {
888 889 890 891 892 893
    // 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 };
894

895 896 897 898
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
899
    Subnet4Ptr subnet = ex.getContext()->subnet_;
900 901 902 903
    if (!subnet) {
        return;
    }

904 905
    Pkt4Ptr resp = ex.getResponse();

906 907 908
    // 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) {
909
        OptionPtr opt = resp->getOption(required_options[i]);
910 911
        if (!opt) {
            // Check whether option has been configured.
912 913
            OptionDescriptor desc = subnet->getCfgOption()->
                get("dhcp4", required_options[i]);
914
            if (desc.option_) {
915
                resp->addOption(desc.option_);
916 917 918
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
919
}
920

921
void
922
Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) {
923 924 925
    // 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.
926
    try {
927
        Pkt4Ptr resp = ex.getResponse();
928
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
929
            (ex.getQuery()->getOption(DHO_FQDN));
930
        if (fqdn) {
931
            LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_FQDN_PROCESS)
932
                .arg(ex.getQuery()->getLabel());
933
            processClientFqdnOption(ex);
934 935

        } else {
936
            OptionStringPtr hostname = boost::dynamic_pointer_cast<OptionString>
937
                (ex.getQuery()->getOption(DHO_HOST_NAME));
938
            if (hostname) {
939
                LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_HOSTNAME_PROCESS)
940
                    .arg(ex.getQuery()->getLabel());
941
                processHostnameOption(ex);
942 943
            }
        }
944
    } catch (const Exception& e) {
945 946 947 948 949 950 951 952
        // 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.
953
        LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
954 955
            .arg(ex.getQuery()->getLabel())
            .arg(e.what());
956 957 958 959
    }
}

void
960
Dhcpv4Srv::processClientFqdnOption(Dhcpv4Exchange& ex) {
961 962 963 964
    // Obtain the FQDN option from the client's message.
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(ex.getQuery()->getOption(DHO_FQDN));

965
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_FQDN_DATA)
966 967 968
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn->toText());