dhcp4_srv.cc 87.9 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 <stats/stats_mgr.h>
44
#include <util/strutil.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
    // Set client identifier if the match-client-id flag is enabled (default).
114 115 116
    // 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) {
117
        if (subnet->getMatchClientId()) {
118 119 120 121 122 123 124 125 126 127
            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());
        }
128 129
    }
    // Check for static reservations.
130
    alloc_engine->findReservation(*context_);
131 132
};

133
void
134
Dhcpv4Exchange::initResponse() {
135 136 137 138 139 140 141 142 143 144 145 146
    uint8_t resp_type = 0;
    switch (getQuery()->getType()) {
    case DHCPDISCOVER:
        resp_type = DHCPOFFER;
        break;
    case DHCPREQUEST:
    case DHCPINFORM:
        resp_type = DHCPACK;
        break;
    default:
        ;
    }
147
    // Only create a response if one is required.
148 149
    if (resp_type > 0) {
        resp_.reset(new Pkt4(resp_type, getQuery()->getTransid()));
150 151 152 153 154 155 156 157 158
        copyDefaultFields();
    }
}

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

159 160
    // explicitly set this to 0
    resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS());
161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199
    // 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);
200 201 202
    }
}

203 204
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

205
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast,
206
                     const bool direct_response_desired)
207 208 209
    : 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) {
210

211
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
212
    try {
213 214 215
        // 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.
216
        if (port) {
217 218 219 220 221 222 223 224
            // 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);
225
        }
226

227
        // Instantiate allocation engine
228 229
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100,
                                            false /* false = IPv4 */));
230

231 232 233 234 235 236 237
        // 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

238
    } catch (const std::exception &e) {
239
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
240 241 242
        shutdown_ = true;
        return;
    }
243

Tomek Mrugalski's avatar
Tomek Mrugalski committed
244
    shutdown_ = false;
245 246 247
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
248
    IfaceMgr::instance().closeSockets();
249 250
}

251 252
void
Dhcpv4Srv::shutdown() {
253
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
254 255 256
    shutdown_ = true;
}

257
isc::dhcp::Subnet4Ptr
258
Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
259 260 261 262 263 264 265 266 267 268 269 270 271 272 273

    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
274
    if (HooksManager::calloutsPresent(hook_index_subnet4_select_)) {
275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294
        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()) {
295
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
296 297
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
298 299 300 301 302 303 304
            return (Subnet4Ptr());
        }

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

305 306
    if (subnet) {
        // Log at higher debug level that subnet has been found.
307
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
308 309 310 311 312 313 314 315 316 317 318 319 320 321
            .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());
    }

322
    return (subnet);
323 324
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
325 326
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
327 328 329
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
330 331
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
332 333 334
    IfaceMgr::instance().send(packet);
}

335 336
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
337
    while (!shutdown_) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
338
        // client's message and server's response
339
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
340
        Pkt4Ptr rsp;
341

342
        try {
343 344 345 346 347 348 349 350 351 352
            // 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;
            }
353
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT).arg(timeout);
354
            query = receivePacket(timeout);
355

356 357 358 359 360 361 362
            // 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) {
363
                LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_BUFFER_RECEIVED)
364 365 366 367 368 369 370 371 372 373 374
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getRemotePort())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getLocalPort())
                    .arg(query->getIface());

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

375 376 377 378 379 380
        } 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.
381 382
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_SIGNAL)
                .arg(signal_set_->getNext());
383
        } catch (const std::exception& e) {
384
            // Log all other errors.
385
            LOG_ERROR(packet_logger, DHCP4_BUFFER_RECEIVE_FAIL).arg(e.what());
386 387
        }

388 389 390
        // 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
391 392 393 394 395 396 397
        // 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.
398 399
        handleSignal();

400 401
        // Execute ready timers for the lease database, e.g. Lease File Cleanup.
        try {
402
            LeaseMgrFactory::instance().getIOService()->poll();
403 404 405 406 407 408

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

409
        // Timeout may be reached or signal received, which breaks select()
410 411
        // with no reception occurred. No need to log anything here because
        // we have logged right after the call to receivePacket().
412 413 414 415
        if (!query) {
            continue;
        }

416 417 418 419 420 421 422 423 424
        // 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));

425 426 427
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
428
        // data; execute callouts registered for buffer4_receive.
429
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
430 431 432 433 434 435 436 437 438
            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
439 440
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
441 442 443 444 445 446

            // Callouts decided to skip the next processing step. The next
            // processing step would to parse the packet, so skip at this
            // stage means that callouts did the parsing already, so server
            // should skip parsing.
            if (callout_handle->getSkip()) {
447
                LOG_DEBUG(hooks_logger, DBG_DHCP4_DETAIL, DHCP4_HOOK_BUFFER_RCVD_SKIP)
448 449 450
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
451 452 453 454 455 456 457 458 459
                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
460
            try {
461 462 463 464
                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
465 466
                query->unpack();
            } catch (const std::exception& e) {
467
                // Failed to parse the packet.
468 469
                LOG_DEBUG(bad_packet_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_DROP_0001)
470 471 472
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface())
473
                    .arg(e.what());
474 475
                continue;
            }
476
        }
477

Tomek Mrugalski's avatar
Tomek Mrugalski committed
478 479 480
        // 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.
481 482
        classifyPacket(query);

483 484 485
        // 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)) {
486
            continue;
487
        }
488

489
        // We have sanity checked (in accept() that the Message Type option
490 491
        // exists, so we can safely get it here.
        int type = query->getType();
492
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_PACKET_RECEIVED)
493
            .arg(query->getLabel())
494
            .arg(query->getName())
495
            .arg(type)
496 497
            .arg(query->getRemoteAddr())
            .arg(query->getLocalAddr())
498
            .arg(query->getIface());
499 500
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
            .arg(query->getLabel())
501 502
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
503
        // Let's execute all callouts registered for pkt4_receive
504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520
        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()) {
521
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP)
522
                    .arg(query->getLabel());
523 524
                continue;
            }
525

526 527
            callout_handle->getArgument("query4", query);
        }
528

529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550
        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:
551
                rsp = processInform(query);
552 553 554 555 556 557 558
                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.
                ;
559
            }
560 561
        } catch (const isc::Exception& e) {

562 563 564 565 566 567
            // 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.)
568 569 570 571
            LOG_DEBUG(bad_packet_logger, DBG_DHCP4_BASIC,
                      DHCP4_PACKET_DROP_0007)
                .arg(query->getLabel())
                .arg(e.what());
572
        }
573

574 575 576
        if (!rsp) {
            continue;
        }
577

578

579 580
        // Specifies if server should do the packing
        bool skip_pack = false;
581

Tomek Mrugalski's avatar
Tomek Mrugalski committed
582
        // Execute all callouts registered for pkt4_send
583 584
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
585

586 587
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
588

589 590
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
591

592 593
            // Set our response
            callout_handle->setArgument("response4", rsp);
594

595 596 597
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
598

599 600 601 602
            // 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()) {
603
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP)
604
                    .arg(query->getLabel());
605 606 607 608 609 610
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
611 612
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_PACK)
                    .arg(rsp->getLabel());
613 614
                rsp->pack();
            } catch (const std::exception& e) {
615 616
                LOG_ERROR(options_logger, DHCP4_PACKET_PACK_FAIL)
                    .arg(rsp->getLabel())
617 618 619 620 621 622 623 624
                    .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
625
            // Let's execute all callouts registered for buffer4_send
626
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
627
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
628

629 630
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
631

632 633
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
634

635
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
636 637
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
638

639 640 641 642
                // 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()) {
643
                    LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
644 645
                              DHCP4_HOOK_BUFFER_SEND_SKIP)
                        .arg(rsp->getLabel());
646
                    continue;
647
                }
648 649

                callout_handle->getArgument("response4", rsp);
650
            }
651

652
            LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND)
653
                .arg(rsp->getLabel())
654
                .arg(rsp->getName())
655 656 657 658 659 660
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->getLocalAddr())
                .arg(rsp->getLocalPort())
                .arg(rsp->getRemoteAddr())
                .arg(rsp->getRemotePort())
                .arg(rsp->getIface());
661 662

            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA,
663
                      DHCP4_RESPONSE_DATA)
664 665 666 667
                .arg(rsp->getLabel())
                .arg(rsp->getName())
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->toText());
668 669
            sendPacket(rsp);
        } catch (const std::exception& e) {
670 671
            LOG_ERROR(packet_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(rsp->getLabel())
672
                .arg(e.what());
673
        }
674 675 676 677 678
    }

    return (true);
}

679
string
680
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696
    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());
697 698
}

699
isc::dhcp_ddns::D2Dhcid
700 701 702 703 704 705 706 707 708
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");

709 710
    }

711 712 713 714 715 716 717 718 719
    // 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);
720

721 722 723
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
724 725

    }
726 727 728

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
729
    try {
730 731 732 733
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
734
            return (D2Dhcid(lease->hwaddr_, fqdn_wire));
735
        }
736
    } catch (const Exception& ex) {
737 738
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
739

740
    }
741 742 743

}

744
void
745
Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) {
746 747 748
    // 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.
749 750
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
751 752 753
    OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                           ex.getResponse()->getLocalAddr()));
    ex.getResponse()->addOption(opt_srvid);
754 755
}

756
void
757
Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) {
758 759
    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
760
    Subnet4Ptr subnet = ex.getContext()->subnet_;
761 762 763 764 765 766 767
    // 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;
    }
768

769 770
    Pkt4Ptr query = ex.getQuery();

771 772 773
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
774
        OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
775 776 777 778 779
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
780

781 782
    Pkt4Ptr resp = ex.getResponse();

783 784 785 786 787 788
    // 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) {
789
        if (!resp->getOption(*opt)) {
790
            OptionDescriptor desc = subnet->getCfgOption()->get("dhcp4", *opt);
791
            if (desc.option_) {
792
                resp->addOption(desc.option_);
793
            }
794 795
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
796
}
797

798
void
799
Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) {
800
    // Get the configured subnet suitable for the incoming packet.
801
    Subnet4Ptr subnet = ex.getContext()->subnet_;
802 803 804 805 806 807 808 809 810 811
    // 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
812 813
    boost::shared_ptr<OptionVendor> vendor_req = boost::dynamic_pointer_cast<
        OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS));
814 815 816 817 818 819 820
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
821 822
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
823 824
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
825 826 827 828 829 830 831 832 833 834

    // 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;
835
    const std::vector<uint8_t>& requested_opts = oro->getValues();
836

Tomek Mrugalski's avatar
Tomek Mrugalski committed
837
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
838
         code != requested_opts.end(); ++code) {
839
        if  (!vendor_rsp->getOption(*code)) {
840 841
            OptionDescriptor desc = subnet->getCfgOption()->get(vendor_id,
                                                                *code);
842 843
            if (desc.option_) {
                vendor_rsp->addOption(desc.option_);
844 845
                added = true;
            }
846 847
        }

848
        if (added) {
849
            ex.getResponse()->addOption(vendor_rsp);
850 851
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
852
}
853

854

855
void
856
Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) {
857 858 859 860 861 862
    // 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 };
863

864 865 866 867
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
868
    Subnet4Ptr subnet = ex.getContext()->subnet_;
869 870 871 872
    if (!subnet) {
        return;
    }

873 874
    Pkt4Ptr resp = ex.getResponse();

875 876 877
    // 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) {
878
        OptionPtr opt = resp->getOption(required_options[i]);
879 880
        if (!opt) {
            // Check whether option has been configured.
881 882
            OptionDescriptor desc = subnet->getCfgOption()->
                get("dhcp4", required_options[i]);
883
            if (desc.option_) {
884
                resp->addOption(desc.option_);
885 886 887
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
888
}
889

890
void
891
Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) {
892 893 894
    // 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.
895
    try {
896
        Pkt4Ptr resp = ex.getResponse();
897
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
898
            (ex.getQuery()->getOption(DHO_FQDN));
899
        if (fqdn) {
900
            LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_FQDN_PROCESS)
901
                .arg(ex.getQuery()->getLabel());
902
            processClientFqdnOption(ex);
903 904

        } else {
905
            OptionStringPtr hostname = boost::dynamic_pointer_cast<OptionString>
906
                (ex.getQuery()->getOption(DHO_HOST_NAME));
907
            if (hostname) {
908
                LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_HOSTNAME_PROCESS)
909
                    .arg(ex.getQuery()->getLabel());
910
                processHostnameOption(ex);
911 912
            }
        }
913
    } catch (const Exception& e) {
914 915 916 917 918 919 920 921
        // 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.
922
        LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
923 924
            .arg(ex.getQuery()->getLabel())
            .arg(e.what());
925 926 927 928
    }
}

void
929
Dhcpv4Srv::processClientFqdnOption(Dhcpv4Exchange& ex) {
930 931 932 933
    // Obtain the FQDN option from the client's message.
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(ex.getQuery()->getOption(DHO_FQDN));

934
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_FQDN_DATA)
935 936 937
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn->toText());

938 939 940 941
    // Create the DHCPv4 Client FQDN Option to be included in the server's
    // response to a client.
    Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));

942 943 944 945
    // 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);
946

947 948 949
    // Carry over the client's E flag.
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E,
                       fqdn->getFlag(Option4ClientFqdn::FLAG_E));
950

951
    if (ex.getContext()->host_ && !ex.getContext()->host_->getHostname().empty()) {
952 953 954
        D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
        fqdn_resp->setDomainName(d2_mgr.qualifyName(ex.getContext()->host_->getHostname(),
                                                    true), Option4ClientFqdn::FULL);
955

956 957 958 959 960
    } 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);
    }
961 962 963 964 965 966 967 968 969 970

    // 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.
Francis Dupont's avatar
Francis Dupont committed
971
    // If we don't store the option in the response message, we will have to
972 973
    // propagate it in the different way to the functions which acquire the
    // lease. This would require modifications to the API of this class.
974
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_RESPONSE_FQDN_DATA)
975 976
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn_resp->toText());