dhcp4_srv.cc 87.8 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
45
#include <log/logger.h>
#include <cryptolink/cryptolink.h>
46
#include <cfgrpt/config_report.h>
47

48
#include <asio.hpp>
49
#include <boost/bind.hpp>
50
#include <boost/foreach.hpp>
51
#include <boost/shared_ptr.hpp>
52
53
54

#include <iomanip>

55
56
using namespace isc;
using namespace isc::asiolink;
57
using namespace isc::cryptolink;
58
using namespace isc::dhcp;
59
using namespace isc::dhcp_ddns;
60
using namespace isc::hooks;
61
62
using namespace isc::log;
using namespace std;
63

64
/// Structure that holds registered hook indexes
65
66
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
67
68
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
69
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
70
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
71
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
72

73
74
75
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
76
77
78
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
79
80
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
81
82
83
84
85
86
87
    }
};

// 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.
88
Dhcp4Hooks Hooks;
89

90
91
92
namespace isc {
namespace dhcp {

93
Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
94
95
                               const Pkt4Ptr& query,
                               const Subnet4Ptr& subnet)
96
97
    : alloc_engine_(alloc_engine), query_(query), resp_(),
      context_(new AllocEngine::ClientContext4()) {
98

99
100
101
102
103
104
105
106
    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");
107
108
    }

109
110
111
    // Create response message.
    initResponse();
    // Select subnet for the query message.
112
    context_->subnet_ = subnet;
113
    // Hardware address.
114
    context_->hwaddr_ = query->getHWAddr();
115
116
117
    // Client Identifier
    OptionPtr opt_clientid = query->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (opt_clientid) {
118
        context_->clientid_.reset(new ClientId(opt_clientid->getData()));
119
120
    }
    // Check for static reservations.
121
    alloc_engine->findReservation(*context_);
122
123
};

124
void
125
Dhcpv4Exchange::initResponse() {
126
127
128
129
130
131
132
133
134
135
136
137
    uint8_t resp_type = 0;
    switch (getQuery()->getType()) {
    case DHCPDISCOVER:
        resp_type = DHCPOFFER;
        break;
    case DHCPREQUEST:
    case DHCPINFORM:
        resp_type = DHCPACK;
        break;
    default:
        ;
    }
138
    // Only create a response if one is required.
139
140
    if (resp_type > 0) {
        resp_.reset(new Pkt4(resp_type, getQuery()->getTransid()));
141
142
143
144
145
146
147
148
149
        copyDefaultFields();
    }
}

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

150
151
    // explicitly set this to 0
    resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS());
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
188
189
190
    // 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);
191
192
193
    }
}

194
195
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

196
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast,
197
                     const bool direct_response_desired)
198
199
200
    : 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) {
201

202
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
203
    try {
204
205
206
        // 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.
207
        if (port) {
208
209
210
211
212
213
214
215
            // 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);
216
        }
217

218
        // Instantiate allocation engine
219
220
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100,
                                            false /* false = IPv4 */));
221

222
223
224
225
226
227
228
        // 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

229
    } catch (const std::exception &e) {
230
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
231
232
233
        shutdown_ = true;
        return;
    }
234

Tomek Mrugalski's avatar
Tomek Mrugalski committed
235
    shutdown_ = false;
236
237
238
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
239
    IfaceMgr::instance().closeSockets();
240
241
}

242
243
void
Dhcpv4Srv::shutdown() {
244
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
245
246
247
    shutdown_ = true;
}

248
isc::dhcp::Subnet4Ptr
249
Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264

    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
265
    if (HooksManager::calloutsPresent(hook_index_subnet4_select_)) {
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
        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()) {
286
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
287
288
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
289
290
291
292
293
294
295
            return (Subnet4Ptr());
        }

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

296
297
    if (subnet) {
        // Log at higher debug level that subnet has been found.
298
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
299
300
301
302
303
304
305
306
307
308
309
310
311
312
            .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());
    }

313
    return (subnet);
314
315
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
316
317
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
318
319
320
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
321
322
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
323
324
325
    IfaceMgr::instance().send(packet);
}

326
327
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
328
    while (!shutdown_) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
329
        // client's message and server's response
330
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
331
        Pkt4Ptr rsp;
332

333
        try {
334
335
336
337
338
339
340
341
342
343
            // 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;
            }
344
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT).arg(timeout);
345
            query = receivePacket(timeout);
346

347
348
349
350
351
352
353
            // 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) {
354
                LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_BUFFER_RECEIVED)
355
356
357
358
359
360
361
362
363
364
365
                    .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);
            }

366
367
368
369
370
371
        } 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.
372
373
            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_SIGNAL)
                .arg(signal_set_->getNext());
374
        } catch (const std::exception& e) {
375
            // Log all other errors.
376
            LOG_ERROR(packet_logger, DHCP4_BUFFER_RECEIVE_FAIL).arg(e.what());
377
378
        }

379
380
381
        // 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
382
383
384
385
386
387
388
        // 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.
389
390
        handleSignal();

391
392
        // Execute ready timers for the lease database, e.g. Lease File Cleanup.
        try {
393
            LeaseMgrFactory::instance().getIOService()->poll();
394
395
396
397
398
399

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

400
        // Timeout may be reached or signal received, which breaks select()
401
402
        // with no reception occurred. No need to log anything here because
        // we have logged right after the call to receivePacket().
403
404
405
406
        if (!query) {
            continue;
        }

407
408
409
410
411
412
413
414
415
        // 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));

416
417
418
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
419
        // data; execute callouts registered for buffer4_receive.
420
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
421
422
423
424
425
426
427
428
429
            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
430
431
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
432
433
434
435
436
437

            // 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()) {
438
                LOG_DEBUG(hooks_logger, DBG_DHCP4_DETAIL, DHCP4_HOOK_BUFFER_RCVD_SKIP)
439
440
441
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
442
443
444
445
446
447
448
449
450
                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
451
            try {
452
453
454
455
                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
456
457
                query->unpack();
            } catch (const std::exception& e) {
458
                // Failed to parse the packet.
459
460
                LOG_DEBUG(bad_packet_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_DROP_0001)
461
462
463
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface())
464
                    .arg(e.what());
465
466
                continue;
            }
467
        }
468

Tomek Mrugalski's avatar
Tomek Mrugalski committed
469
470
471
        // 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.
472
473
        classifyPacket(query);

474
475
476
        // 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)) {
477
            continue;
478
        }
479

480
        // We have sanity checked (in accept() that the Message Type option
481
482
        // exists, so we can safely get it here.
        int type = query->getType();
483
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_PACKET_RECEIVED)
484
            .arg(query->getLabel())
485
            .arg(query->getName())
486
            .arg(type)
487
488
            .arg(query->getRemoteAddr())
            .arg(query->getLocalAddr())
489
            .arg(query->getIface());
490
491
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
            .arg(query->getLabel())
492
493
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
494
        // Let's execute all callouts registered for pkt4_receive
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
        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()) {
512
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP)
513
                    .arg(query->getLabel());
514
515
                continue;
            }
516

517
518
            callout_handle->getArgument("query4", query);
        }
519

520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
        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:
542
                rsp = processInform(query);
543
544
545
546
547
548
549
                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.
                ;
550
            }
551
552
        } catch (const isc::Exception& e) {

553
554
555
556
557
558
            // 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.)
559
560
561
562
            LOG_DEBUG(bad_packet_logger, DBG_DHCP4_BASIC,
                      DHCP4_PACKET_DROP_0007)
                .arg(query->getLabel())
                .arg(e.what());
563
        }
564

565
566
567
        if (!rsp) {
            continue;
        }
568

569

570
571
        // Specifies if server should do the packing
        bool skip_pack = false;
572

Tomek Mrugalski's avatar
Tomek Mrugalski committed
573
        // Execute all callouts registered for pkt4_send
574
575
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
576

577
578
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
579

580
581
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
582

583
584
            // Set our response
            callout_handle->setArgument("response4", rsp);
585

586
587
588
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
589

590
591
592
593
            // 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()) {
594
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP)
595
                    .arg(query->getLabel());
596
597
598
599
600
601
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
602
603
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_PACK)
                    .arg(rsp->getLabel());
604
605
                rsp->pack();
            } catch (const std::exception& e) {
606
607
                LOG_ERROR(options_logger, DHCP4_PACKET_PACK_FAIL)
                    .arg(rsp->getLabel())
608
609
610
611
612
613
614
615
                    .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
616
            // Let's execute all callouts registered for buffer4_send
617
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
618
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
619

620
621
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
622

623
624
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
625

626
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
627
628
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
629

630
631
632
633
                // 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()) {
634
                    LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
635
636
                              DHCP4_HOOK_BUFFER_SEND_SKIP)
                        .arg(rsp->getLabel());
637
                    continue;
638
                }
639
640

                callout_handle->getArgument("response4", rsp);
641
            }
642

643
            LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND)
644
                .arg(rsp->getLabel())
645
                .arg(rsp->getName())
646
647
648
649
650
651
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->getLocalAddr())
                .arg(rsp->getLocalPort())
                .arg(rsp->getRemoteAddr())
                .arg(rsp->getRemotePort())
                .arg(rsp->getIface());
652
653

            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA,
654
                      DHCP4_RESPONSE_DATA)
655
656
657
658
                .arg(rsp->getLabel())
                .arg(rsp->getName())
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->toText());
659
660
            sendPacket(rsp);
        } catch (const std::exception& e) {
661
662
            LOG_ERROR(packet_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(rsp->getLabel())
663
                .arg(e.what());
664
        }
665
666
667
668
669
    }

    return (true);
}

670
string
671
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
    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());
688
689
}

690
isc::dhcp_ddns::D2Dhcid
691
692
693
694
695
696
697
698
699
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");

700
701
    }

702
703
704
705
706
707
708
709
710
    // 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);
711

712
713
714
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
715
716

    }
717
718
719

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
720
    try {
721
722
723
724
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
725
            return (D2Dhcid(lease->hwaddr_, fqdn_wire));
726
        }
727
    } catch (const Exception& ex) {
728
729
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
730

731
    }
732
733
734

}

735
void
736
Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) {
737
738
739
    // 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.
740
741
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
742
743
744
    OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                           ex.getResponse()->getLocalAddr()));
    ex.getResponse()->addOption(opt_srvid);
745
746
}

747
void
748
Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) {
749
750
    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
751
    Subnet4Ptr subnet = ex.getContext()->subnet_;
752
753
754
755
756
757
758
    // 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;
    }
759

760
761
    Pkt4Ptr query = ex.getQuery();

762
763
764
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
765
        OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
766
767
768
769
770
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
771

772
773
    Pkt4Ptr resp = ex.getResponse();

774
775
776
777
778
779
    // 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) {
780
        if (!resp->getOption(*opt)) {
781
            OptionDescriptor desc = subnet->getCfgOption()->get("dhcp4", *opt);
782
            if (desc.option_) {
783
                resp->addOption(desc.option_);
784
            }
785
786
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
787
}
788

789
void
790
Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) {
791
    // Get the configured subnet suitable for the incoming packet.
792
    Subnet4Ptr subnet = ex.getContext()->subnet_;
793
794
795
796
797
798
799
800
801
802
    // 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
803
804
    boost::shared_ptr<OptionVendor> vendor_req = boost::dynamic_pointer_cast<
        OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS));
805
806
807
808
809
810
811
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
812
813
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
814
815
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
816
817
818
819
820
821
822
823
824
825

    // 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;
826
    const std::vector<uint8_t>& requested_opts = oro->getValues();
827

Tomek Mrugalski's avatar
Tomek Mrugalski committed
828
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
829
         code != requested_opts.end(); ++code) {
830
        if  (!vendor_rsp->getOption(*code)) {
831
832
            OptionDescriptor desc = subnet->getCfgOption()->get(vendor_id,
                                                                *code);
833
834
            if (desc.option_) {
                vendor_rsp->addOption(desc.option_);
835
836
                added = true;
            }
837
838
        }

839
        if (added) {
840
            ex.getResponse()->addOption(vendor_rsp);
841
842
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
843
}
844

845

846
void
847
Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) {
848
849
850
851
852
853
    // 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 };
854

855
856
857
858
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
859
    Subnet4Ptr subnet = ex.getContext()->subnet_;
860
861
862
863
    if (!subnet) {
        return;
    }

864
865
    Pkt4Ptr resp = ex.getResponse();

866
867
868
    // 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) {
869
        OptionPtr opt = resp->getOption(required_options[i]);
870
871
        if (!opt) {
            // Check whether option has been configured.
872
873
            OptionDescriptor desc = subnet->getCfgOption()->
                get("dhcp4", required_options[i]);
874
            if (desc.option_) {
875
                resp->addOption(desc.option_);
876
877
878
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
879
}
880

881
void
882
Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) {
883
884
885
    // 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.
886
    try {
887
        Pkt4Ptr resp = ex.getResponse();
888
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
889
            (ex.getQuery()->getOption(DHO_FQDN));
890
        if (fqdn) {
891
            LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_FQDN_PROCESS)
892
                .arg(ex.getQuery()->getLabel());
893
            processClientFqdnOption(ex);
894
895

        } else {
896
            OptionStringPtr hostname = boost::dynamic_pointer_cast<OptionString>
897
                (ex.getQuery()->getOption(DHO_HOST_NAME));
898
            if (hostname) {
899
                LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_HOSTNAME_PROCESS)
900
                    .arg(ex.getQuery()->getLabel());
901
                processHostnameOption(ex);
902
903
            }
        }
904
    } catch (const Exception& e) {
905
906
907
908
909
910
911
912
        // 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.
913
        LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
914
915
            .arg(ex.getQuery()->getLabel())
            .arg(e.what());
916
917
918
919
    }
}

void
920
Dhcpv4Srv::processClientFqdnOption(Dhcpv4Exchange& ex) {
921
922
923
924
    // Obtain the FQDN option from the client's message.
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(ex.getQuery()->getOption(DHO_FQDN));

925
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_FQDN_DATA)
926
927
928
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn->toText());

929
930
931
932
    // Create the DHCPv4 Client FQDN Option to be included in the server's
    // response to a client.
    Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));

933
934
935
936
    // 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);
937

938
939
940
    // Carry over the client's E flag.
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E,
                       fqdn->getFlag(Option4ClientFqdn::FLAG_E));
941

942
    if (ex.getContext()->host_ && !ex.getContext()->host_->getHostname().empty()) {
943
944
945
        D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
        fqdn_resp->setDomainName(d2_mgr.qualifyName(ex.getContext()->host_->getHostname(),
                                                    true), Option4ClientFqdn::FULL);
946

947
948
949
950
951
    } 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);
    }
952
953
954
955
956
957
958
959
960
961

    // 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
962
    // If we don't store the option in the response message, we will have to
963
964
    // propagate it in the different way to the functions which acquire the
    // lease. This would require modifications to the API of this class.
965
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_RESPONSE_FQDN_DATA)
966
967
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn_resp->toText());
968
    ex.getResponse()->addOption(fqdn_resp);
969
970
971
}

void
972
Dhcpv4Srv::processHostnameOption(Dhcpv4Exchange& ex) {
973
974
975
976
    // Obtain the Hostname option from the client's message.
    OptionStringPtr opt_hostname = boost::dynamic_pointer_cast<OptionString>
        (ex.getQuery()->getOption(DHO_HOST_NAME));

977
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_HOSTNAME_DATA)
978
979
980
        .arg(ex.getQuery()->getLabel())
        .arg(opt_hostname->getValue());

981
982
983
    // Fetch D2 configuration.
    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();

984
    // Do nothing if the DNS updates are disabled.
985
    if (!d2_mgr.ddnsEnabled()) {
986
987
988
        return;
    }

989
    std::string hostname = isc::util::str::trim(opt_hostname->getValue());
990
    unsigned int label_count = OptionDataTypeUtil::getLabelCount(hostname);
991
    // The hostname option sent by the client should be at least 1 octet long.
992
993
994
    // If it isn't we ignore this option. (Per RFC 2131, section 3.14)
    /// @todo It would be more liberal to accept this and let it fall into
    /// the case  of replace or less than two below.
995
    if (label_count == 0) {
996
        LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_EMPTY_HOSTNAME)
997
            .arg(ex.getQuery()->getLabel());
998
999
        return;
    }
1000
    // Copy construct the hostname provided by the client. It is entirely
For faster browsing, not all history is shown. View entire blame