dhcp4_srv.cc 68.2 KB
Newer Older
1
// Copyright (C) 2011-2014 Internet Systems Consortium, Inc. ("ISC")
2
3
4
5
6
7
8
9
10
11
12
13
14
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

15
#include <asiolink/io_address.h>
16
#include <dhcp/dhcp4.h>
17
18
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
19
#include <dhcp/iface_mgr.h>
20
#include <dhcp/option4_addrlst.h>
21
#include <dhcp/option_int.h>
22
#include <dhcp/option_int_array.h>
23
#include <dhcp/option_vendor.h>
24
#include <dhcp/pkt4.h>
25
#include <dhcp/docsis3_option_defs.h>
26
27
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
28
29
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
30
31
32
33
34
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
#include <dhcpsrv/subnet.h>
#include <dhcpsrv/utils.h>
35
#include <dhcpsrv/utils.h>
36
#include <hooks/callout_handle.h>
37
#include <hooks/hooks_manager.h>
38
#include <util/strutil.h>
39

40
#include <boost/bind.hpp>
41
#include <boost/foreach.hpp>
42
43
44

#include <iomanip>

45
46
using namespace isc;
using namespace isc::asiolink;
47
using namespace isc::dhcp;
48
using namespace isc::dhcp_ddns;
49
using namespace isc::hooks;
50
51
using namespace isc::log;
using namespace std;
52

53
/// Structure that holds registered hook indexes
54
55
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
56
57
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
58
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
59
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
60
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
61

62
63
64
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
65
66
67
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
68
69
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
70
71
72
73
74
75
76
    }
};

// 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.
77
Dhcp4Hooks Hooks;
78

79
80
81
namespace isc {
namespace dhcp {

82
83
namespace {

84
// @todo The following constants describe server's behavior with respect to the
85
86
87
// DHCPv4 Client FQDN Option sent by a client. They will be removed
// when DDNS parameters for DHCPv4 are implemented with the ticket #3033.

88
89
90
91
92
// @todo Additional configuration parameter which we may consider is the one
// that controls whether the DHCP server sends the removal NameChangeRequest
// if it discovers that the entry for the particular client exists or that
// it always updates the DNS.

93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
// Should server always include the FQDN option in its response, regardless
// if it has been requested in Parameter Request List Option (Disabled).
const bool FQDN_ALWAYS_INCLUDE = false;
// Enable A RR update delegation to the client (Disabled).
const bool FQDN_ALLOW_CLIENT_UPDATE = false;
// Globally enable updates (Enabled).
const bool FQDN_ENABLE_UPDATE = true;
// Do update, even if client requested no updates with N flag (Disabled).
const bool FQDN_OVERRIDE_NO_UPDATE = false;
// Server performs an update when client requested delegation (Enabled).
const bool FQDN_OVERRIDE_CLIENT_UPDATE = true;
// The fully qualified domain-name suffix if partial name provided by
// a client.
const char* FQDN_PARTIAL_SUFFIX = "example.com";
// Should server replace the domain-name supplied by the client (Disabled).
const bool FQDN_REPLACE_CLIENT_NAME = false;

}

112
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const char* dbconfig, const bool use_bcast,
113
                     const bool direct_response_desired)
114
: shutdown_(true), alloc_engine_(), port_(port),
115
    use_bcast_(use_bcast), hook_index_pkt4_receive_(-1),
116
117
    hook_index_subnet4_select_(-1), hook_index_pkt4_send_(-1) {

118
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
119
    try {
120
121
122
123
        // Open sockets only if port is non-zero. Port 0 is used for testing
        // purposes in two cases:
        // - when non-socket related testing is performed
        // - when the particular test supplies its own packet filtering class.
124
        if (port) {
125
126
127
128
129
130
131
132
133
            // 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);

134
135
136
137
138
139
            // Create error handler. This handler will be called every time
            // the socket opening operation fails. We use this handler to
            // log a warning.
            isc::dhcp::IfaceMgrErrorMsgCallback error_handler =
                boost::bind(&Dhcpv4Srv::ifaceMgrSocket4ErrorHandler, _1);
            IfaceMgr::instance().openSockets4(port_, use_bcast_, error_handler);
140
        }
141

142
143
144
145
146
147
148
        // Instantiate LeaseMgr
        LeaseMgrFactory::create(dbconfig);
        LOG_INFO(dhcp4_logger, DHCP4_DB_BACKEND_STARTED)
            .arg(LeaseMgrFactory::instance().getType())
            .arg(LeaseMgrFactory::instance().getName());

        // Instantiate allocation engine
149
150
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100,
                                            false /* false = IPv4 */));
151

152
153
154
155
156
157
158
        // 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

159
    } catch (const std::exception &e) {
160
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
161
162
163
        shutdown_ = true;
        return;
    }
164

Tomek Mrugalski's avatar
Tomek Mrugalski committed
165
    shutdown_ = false;
166
167
168
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
169
    IfaceMgr::instance().closeSockets();
170
171
}

172
173
void
Dhcpv4Srv::shutdown() {
174
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
175
176
177
    shutdown_ = true;
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
178
179
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
180
181
182
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
183
184
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
185
186
187
    IfaceMgr::instance().send(packet);
}

188
189
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
190
    while (!shutdown_) {
191
        /// @todo: calculate actual timeout once we have lease database
192
193
        //cppcheck-suppress variableScope This is temporary anyway
        const int timeout = 1000;
194

Tomek Mrugalski's avatar
Tomek Mrugalski committed
195
        // client's message and server's response
196
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
197
        Pkt4Ptr rsp;
198

199
        try {
200
            query = receivePacket(timeout);
201
202
203
204
        } catch (const std::exception& e) {
            LOG_ERROR(dhcp4_logger, DHCP4_PACKET_RECEIVE_FAIL).arg(e.what());
        }

205
206
207
208
209
210
        // Timeout may be reached or signal received, which breaks select()
        // with no reception ocurred
        if (!query) {
            continue;
        }

211
212
213
214
215
216
217
218
219
        // 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));

220
221
222
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
223
        // data; execute callouts registered for buffer4_receive.
224
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
225
226
227
228
229
230
231
232
233
            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
234
235
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251

            // Callouts decided to skip the next processing step. The next
            // processing step would to parse the packet, so skip at this
            // stage means that callouts did the parsing already, so server
            // should skip parsing.
            if (callout_handle->getSkip()) {
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_BUFFER_RCVD_SKIP);
                skip_unpack = true;
            }

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

        // Unpack the packet information unless the buffer4_receive callouts
        // indicated they did it
        if (!skip_unpack) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
252
253
254
            try {
                query->unpack();
            } catch (const std::exception& e) {
255
256
257
                // Failed to parse the packet.
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_PARSE_FAIL).arg(e.what());
258
259
                continue;
            }
260
        }
261

262
263
264
265
266
267
268
269
        // Check if the DHCPv4 packet has been sent to us, to to someone else.
        // If it hasn't been sent to us, drop it!
        if (!acceptServerId(query)) {
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_NOT_FOR_US)
                .arg(query->getIface());
            continue;
        }

270
271
272
273
274
        // When receiving a packet without message type option, getType() will
        // throw. Let's set type to -1 as default error indicator.
        int type = -1;
        try {
            type = query->getType();
275
276
277
278
        } catch (...) {
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_NO_TYPE)
                .arg(query->getIface());
            continue;
279
        }
280

281
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_RECEIVED)
282
            .arg(serverReceivedPacketName(type))
283
            .arg(type)
284
285
            .arg(query->getIface());
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
286
            .arg(type)
287
288
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
289
        // Let's execute all callouts registered for pkt4_receive
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
        if (HooksManager::calloutsPresent(hook_index_pkt4_receive_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);

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

            // Pass incoming packet as argument
            callout_handle->setArgument("query4", query);

            // Call callouts
            HooksManager::callCallouts(hook_index_pkt4_receive_,
                                       *callout_handle);

            // Callouts decided to skip the next processing step. The next
            // processing step would to process the packet, so skip at this
            // stage means drop.
            if (callout_handle->getSkip()) {
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP);
                continue;
            }
310

311
312
            callout_handle->getArgument("query4", query);
        }
313

314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
        try {
            switch (query->getType()) {
            case DHCPDISCOVER:
                rsp = processDiscover(query);
                break;

            case DHCPREQUEST:
                // Note that REQUEST is used for many things in DHCPv4: for
                // requesting new leases, renewing existing ones and even
                // for rebinding.
                rsp = processRequest(query);
                break;

            case DHCPRELEASE:
                processRelease(query);
                break;

            case DHCPDECLINE:
                processDecline(query);
                break;

            case DHCPINFORM:
                processInform(query);
                break;

            default:
                // Only action is to output a message if debug is enabled,
                // and that is covered by the debug statement before the
                // "switch" statement.
                ;
344
            }
345
346
347
348
349
350
351
352
353
354
355
356
357
358
        } catch (const isc::Exception& e) {

            // Catch-all exception (at least for ones based on the isc
            // Exception class, which covers more or less all that
            // are explicitly raised in the BIND 10 code).  Just log
            // the problem and ignore the packet. (The problem is logged
            // as a debug message because debug is disabled by default -
            // it prevents a DDOS attack based on the sending of problem
            // packets.)
            if (dhcp4_logger.isDebugEnabled(DBG_DHCP4_BASIC)) {
                std::string source = "unknown";
                HWAddrPtr hwptr = query->getHWAddr();
                if (hwptr) {
                    source = hwptr->toText();
359
                }
360
361
362
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC,
                          DHCP4_PACKET_PROCESS_FAIL)
                    .arg(source).arg(e.what());
363
            }
364
        }
365

366
367
368
        if (!rsp) {
            continue;
        }
369

370
371
        // Specifies if server should do the packing
        bool skip_pack = false;
372

Tomek Mrugalski's avatar
Tomek Mrugalski committed
373
        // Execute all callouts registered for pkt4_send
374
375
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
376

377
378
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
379

380
381
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
382

383
384
            // Set our response
            callout_handle->setArgument("response4", rsp);
385

386
387
388
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
389

390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
            // Callouts decided to skip the next processing step. The next
            // processing step would to send the packet, so skip at this
            // stage means "drop response".
            if (callout_handle->getSkip()) {
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP);
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
                rsp->pack();
            } catch (const std::exception& e) {
                LOG_ERROR(dhcp4_logger, DHCP4_PACKET_SEND_FAIL)
                    .arg(e.what());
            }
        }

        try {
            // Now all fields and options are constructed into output wire buffer.
            // Option objects modification does not make sense anymore. Hooks
            // can only manipulate wire buffer at this stage.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
412
            // Let's execute all callouts registered for buffer4_send
413
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
414
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
415

416
417
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
418

419
420
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
421

422
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
423
424
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
425

426
427
428
429
                // Callouts decided to skip the next processing step. The next
                // processing step would to parse the packet, so skip at this
                // stage means drop.
                if (callout_handle->getSkip()) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
430
431
                    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_HOOKS,
                              DHCP4_HOOK_BUFFER_SEND_SKIP);
432
                    continue;
433
                }
434
435

                callout_handle->getArgument("response4", rsp);
436
            }
437
438
439
440
441
442
443
444
445

            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA,
                      DHCP4_RESPONSE_DATA)
                .arg(static_cast<int>(rsp->getType())).arg(rsp->toText());

            sendPacket(rsp);
        } catch (const std::exception& e) {
            LOG_ERROR(dhcp4_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(e.what());
446
        }
447
448
449

        // Send NameChangeRequests to the b10-dhcp_ddns module.
        sendNameChangeRequests();
450
451
452
453
454
    }

    return (true);
}

455
string
456
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
    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());
473
474
}

475
isc::dhcp_ddns::D2Dhcid
476
477
478
479
480
481
482
483
484
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");

485
486
    }

487
488
489
490
491
492
493
494
495
    // 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);
496

497
498
499
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
500
501

    }
502
503
504

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
505
    try {
506
507
508
509
510
511
512
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
            HWAddrPtr hwaddr(new HWAddr(lease->hwaddr_, HTYPE_ETHER));
            return (D2Dhcid(hwaddr, fqdn_wire));
        }
513
    } catch (const Exception& ex) {
514
515
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
516

517
    }
518
519
520

}

521
522
void
Dhcpv4Srv::copyDefaultFields(const Pkt4Ptr& question, Pkt4Ptr& answer) {
523
524
525
    answer->setIface(question->getIface());
    answer->setIndex(question->getIndex());
    answer->setCiaddr(question->getCiaddr());
526

527
    answer->setSiaddr(IOAddress("0.0.0.0")); // explicitly set this to 0
528
    answer->setHops(question->getHops());
529
530

    // copy MAC address
531
    answer->setHWAddr(question->getHWAddr());
532
533

    // relay address
534
535
    answer->setGiaddr(question->getGiaddr());

536
    // Let's copy client-id to response. See RFC6842.
537
538
    // It is possible to disable RFC6842 to keep backward compatibility
    bool echo = CfgMgr::instance().echoClientId();
539
    OptionPtr client_id = question->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
540
    if (client_id && echo) {
541
542
        answer->addOption(client_id);
    }
543
544

    // If src/dest HW addresses are used by the packet filtering class
545
546
547
548
549
550
    // 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.
551
552
    HWAddrPtr src_hw_addr = question->getLocalHWAddr();
    if (src_hw_addr) {
553
        answer->setLocalHWAddr(src_hw_addr);
554
    }
555
    HWAddrPtr dst_hw_addr = question->getRemoteHWAddr();
556
    if (dst_hw_addr) {
557
        answer->setRemoteHWAddr(dst_hw_addr);
558
    }
559
560
561
562
563
564

    // If this packet is relayed, we want to copy Relay Agent Info option
    OptionPtr rai = question->getOption(DHO_DHCP_AGENT_OPTIONS);
    if (rai) {
        answer->addOption(rai);
    }
565
566
}

567
568
void
Dhcpv4Srv::appendDefaultOptions(Pkt4Ptr& msg, uint8_t msg_type) {
569
    OptionPtr opt;
570
571

    // add Message Type Option (type 53)
572
    msg->setType(msg_type);
573
574
575
576

    // more options will be added here later
}

577
578
579
580
581
582
583
584
585
586
587
588
void
Dhcpv4Srv::appendServerID(const Pkt4Ptr& response) {
    // 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.
    // @todo: perhaps we should consider some more sophisticated server id
    // generation, but for the current use cases, it should be ok.
    response->addOption(OptionPtr(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                                     response->getLocalAddr()))
                        );
}

589
590
void
Dhcpv4Srv::appendRequestedOptions(const Pkt4Ptr& question, Pkt4Ptr& msg) {
591
592
593
594
595
596
597
598
599
600
601

    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
    Subnet4Ptr subnet = selectSubnet(question);
    // If we can't find the subnet for the client there is no way
    // to get the options to be sent to a client. We don't log an
    // error because it will be logged by the assignLease method
    // anyway.
    if (!subnet) {
        return;
    }
602

603
604
605
606
607
608
609
610
611
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
        OptionUint8Array>(question->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
612

613
614
615
616
617
618
    // 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) {
619
620
621
622
623
624
        if (!msg->getOption(*opt)) {
            Subnet::OptionDescriptor desc =
                subnet->getOptionDescriptor("dhcp4", *opt);
            if (desc.option && !msg->getOption(*opt)) {
                msg->addOption(desc.option);
            }
625
626
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
627
}
628

629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
void
Dhcpv4Srv::appendRequestedVendorOptions(const Pkt4Ptr& question, Pkt4Ptr& answer) {
    // Get the configured subnet suitable for the incoming packet.
    Subnet4Ptr subnet = selectSubnet(question);
    // 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
    boost::shared_ptr<OptionVendor> vendor_req =
        boost::dynamic_pointer_cast<OptionVendor>(question->getOption(DHO_VIVSO_SUBOPTIONS));
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other vendors
    /// may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
654
655
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
656
657
658
659
660
661
662
663
664
665

    // 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;
666
    const std::vector<uint8_t>& requested_opts = oro->getValues();
667

Tomek Mrugalski's avatar
Tomek Mrugalski committed
668
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
669
         code != requested_opts.end(); ++code) {
670
671
672
673
674
675
676
        if  (!vendor_rsp->getOption(*code)) {
            Subnet::OptionDescriptor desc = subnet->getVendorOptionDescriptor(vendor_id,
                                                                              *code);
            if (desc.option) {
                vendor_rsp->addOption(desc.option);
                added = true;
            }
677
678
        }

679
680
        if (added) {
            answer->addOption(vendor_rsp);
681
682
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
683
}
684

685

686
687
688
689
690
691
692
693
void
Dhcpv4Srv::appendBasicOptions(const Pkt4Ptr& question, Pkt4Ptr& msg) {
    // Identify options that we always want to send to the
    // client (if they are configured).
    static const uint16_t required_options[] = {
        DHO_ROUTERS,
        DHO_DOMAIN_NAME_SERVERS,
        DHO_DOMAIN_NAME };
694

695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
    Subnet4Ptr subnet = selectSubnet(question);
    if (!subnet) {
        return;
    }

    // Try to find all 'required' options in the outgoing
    // message. Those that are not present will be added.
    for (int i = 0; i < required_options_size; ++i) {
        OptionPtr opt = msg->getOption(required_options[i]);
        if (!opt) {
            // Check whether option has been configured.
            Subnet::OptionDescriptor desc =
                subnet->getOptionDescriptor("dhcp4", required_options[i]);
            if (desc.option) {
                msg->addOption(desc.option);
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
717
}
718

719
720
721
722
723
void
Dhcpv4Srv::processClientName(const Pkt4Ptr& query, Pkt4Ptr& answer) {
    // It is possible that client has sent both Client FQDN and Hostname
    // option. In such case, server should prefer Client FQDN option and
    // ignore the Hostname option.
724
725
726
727
728
729
730
731
732
733
734
735
    try {
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
            (query->getOption(DHO_FQDN));
        if (fqdn) {
            processClientFqdnOption(fqdn, answer);

        } else {
            OptionCustomPtr hostname = boost::dynamic_pointer_cast<OptionCustom>
                (query->getOption(DHO_HOST_NAME));
            if (hostname) {
                processHostnameOption(hostname, answer);
            }
736

737
738
739
740
741
742
743
744
745
746
747
748
        }
    } catch (const Exception& ex) {
        // 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.
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
            .arg(ex.what());
749
750
751
752
    }
}

void
753
754
755
756
757
758
759
760
761
762
763
Dhcpv4Srv::processClientFqdnOption(const Option4ClientFqdnPtr& fqdn,
                                   Pkt4Ptr& answer) {
    // Create the DHCPv4 Client FQDN Option to be included in the server's
    // response to a client.
    Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));

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

764
765
766
767
    // Conditions when N flag has to be set to indicate that server will not
    // perform DNS updates:
    // 1. Updates are globally disabled,
    // 2. Client requested no update and server respects it,
768
769
770
771
    // 3. Client requested that the forward DNS update is delegated to the
    //    client but server neither respects requests for forward update
    //    delegation nor it is configured to send update on its own when
    //    client requested delegation.
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
    if (!FQDN_ENABLE_UPDATE ||
        (fqdn->getFlag(Option4ClientFqdn::FLAG_N) &&
         !FQDN_OVERRIDE_NO_UPDATE) ||
        (!fqdn->getFlag(Option4ClientFqdn::FLAG_S) &&
         !FQDN_ALLOW_CLIENT_UPDATE && !FQDN_OVERRIDE_CLIENT_UPDATE)) {
        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_N, true);

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

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

    // If client suppled partial or empty domain-name, server should generate
    // one.
    if (fqdn->getDomainNameType() == Option4ClientFqdn::PARTIAL) {
        std::ostringstream name;
804
        if (fqdn->getDomainName().empty() || FQDN_REPLACE_CLIENT_NAME) {
805
806
            fqdn_resp->setDomainName("", Option4ClientFqdn::PARTIAL);

807
808
        } else {
            name << fqdn->getDomainName();
809
810
811
            name << "." << FQDN_PARTIAL_SUFFIX;
            fqdn_resp->setDomainName(name.str(), Option4ClientFqdn::FULL);

812
813
814
        }

    // Server may be configured to replace a name supplied by a client, even if
815
816
817
    // client supplied fully qualified domain-name. The empty domain-name is
    // is set to indicate that the name must be generated when the new lease
    // is acquired.
818
    } else if(FQDN_REPLACE_CLIENT_NAME) {
819
        fqdn_resp->setDomainName("", Option4ClientFqdn::PARTIAL);
820
821
822
823
824
825
826
827
828
829
830
831
832
833
    }

    // Add FQDN option to the response message. Note that, there may be some
    // cases when server may choose not to include the FQDN option in a
    // response to a client. In such cases, the FQDN should be removed from the
    // outgoing message. In theory we could cease to include the FQDN option
    // in this function until it is confirmed that it should be included.
    // However, we include it here for simplicity. Functions used to acquire
    // lease for a client will scan the response message for FQDN and if it
    // is found they will take necessary actions to store the FQDN information
    // in the lease database as well as to generate NameChangeRequests to DNS.
    // If we don't store the option in the reponse message, we will have to
    // propagate it in the different way to the functions which acquire the
    // lease. This would require modifications to the API of this class.
834
    answer->addOption(fqdn_resp);
835
836
837
}

void
838
839
Dhcpv4Srv::processHostnameOption(const OptionCustomPtr& opt_hostname,
                                 Pkt4Ptr& answer) {
840
    // Do nothing if the DNS updates are disabled.
841
842
843
844
    if (!FQDN_ENABLE_UPDATE) {
        return;
    }

845
    std::string hostname = isc::util::str::trim(opt_hostname->readString());
846
    unsigned int label_count = OptionDataTypeUtil::getLabelCount(hostname);
847
848
849
850
851
852
    // The hostname option sent by the client should be at least 1 octet long.
    // If it isn't we ignore this option.
    if (label_count == 0) {
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_EMPTY_HOSTNAME);
        return;
    }
853
854
855
856
857
858
859
860
861
862
863
864
865
    // Copy construct the hostname provided by the client. It is entirely
    // possible that we will use the hostname option provided by the client
    // to perform the DNS update and we will send the same option to him to
    // indicate that we accepted this hostname.
    OptionCustomPtr opt_hostname_resp(new OptionCustom(*opt_hostname));

    // The hostname option may be unqualified or fully qualified. The lab_count
    // holds the number of labels for the name. The number of 1 means that
    // there is only root label "." (even for unqualified names, as the
    // getLabelCount function treats each name as a fully qualified one).
    // By checking the number of labels present in the hostname we may infer
    // whether client has sent the fully qualified or unqualified hostname.

866
867
868
869
870
871
    // @todo We may want to reconsider whether it is appropriate for the
    // client to send a root domain name as a Hostname. There are
    // also extensions to the auto generation of the client's name,
    // e.g. conversion to the puny code which may be considered at some point.
    // For now, we just remain liberal and expect that the DNS will handle
    // conversion if needed and possible.
872
    if (FQDN_REPLACE_CLIENT_NAME || (label_count < 2)) {
873
        opt_hostname_resp->writeString("");
874
875
876
877
878
879
880
881
882
883
    // If there are two labels, it means that the client has specified
    // the unqualified name. We have to concatenate the unqalified name
    // with the domain name.
    } else if (label_count == 2) {
        std::ostringstream resp_hostname;
        resp_hostname << hostname << "." << FQDN_PARTIAL_SUFFIX << ".";
        opt_hostname_resp->writeString(resp_hostname.str());
    }

    answer->addOption(opt_hostname_resp);
884
885
}

886
887
void
Dhcpv4Srv::createNameChangeRequests(const Lease4Ptr& lease,
888
                                    const Lease4Ptr& old_lease) {
889
890
891
892
893
    if (!lease) {
        isc_throw(isc::Unexpected,
                  "NULL lease specified when creating NameChangeRequest");
    }

894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
    // If old lease is not NULL, it is an indication that the lease has
    // just been renewed. In such case we may need to generate the
    // additional NameChangeRequest to remove an existing entry before
    // we create a NameChangeRequest to add the entry for an updated lease.
    // We may also decide not to generate any requests at all. This is when
    // we discover that nothing has changed in the client's FQDN data.
    if (old_lease) {
        if (!lease->matches(*old_lease)) {
            isc_throw(isc::Unexpected,
                      "there is no match between the current instance of the"
                      " lease: " << lease->toText() << ", and the previous"
                      " instance: " << lease->toText());
        } else {
            // There will be a NameChangeRequest generated to remove existing
            // DNS entries if the following conditions are met:
            // - The hostname is set for the existing lease, we can't generate
            //   removal request for non-existent hostname.
            // - A server has performed reverse, forward or both updates.
            // - FQDN data between the new and old lease do not match.
913
            if  ((lease->hostname_ != old_lease->hostname_) ||
914
                 (lease->fqdn_fwd_ != old_lease->fqdn_fwd_) ||
915
916
917
                 (lease->fqdn_rev_ != old_lease->fqdn_rev_)) {
                queueNameChangeRequest(isc::dhcp_ddns::CHG_REMOVE,
                                       old_lease);
918
919
920
921
922
923
924
925
926
927
928

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

        }
    }

929
930
931
932
    // We may need to generate the NameChangeRequest for the new lease. It
    // will be generated only if hostname is set and if forward or reverse
    // update has been requested.
    queueNameChangeRequest(isc::dhcp_ddns::CHG_ADD, lease);
933
934
}

935
936
void
Dhcpv4Srv::
937
938
939
940
941
942
943
944
queueNameChangeRequest(const isc::dhcp_ddns::NameChangeType chg_type,
                       const Lease4Ptr& lease) {
    // The hostname must not be empty, and at least one type of update
    // should be requested.
    if (!lease || lease->hostname_.empty() ||
        (!lease->fqdn_rev_ && !lease->fqdn_fwd_)) {
        return;
    }
945
946

    // Create the DHCID for the NameChangeRequest.
947
948
949
950
951
952
953
954
955
    D2Dhcid dhcid;
    try {
        dhcid  = computeDhcid(lease);
    } catch (const DhcidComputeError& ex) {
        LOG_ERROR(dhcp4_logger, DHCP4_DHCID_COMPUTE_ERROR)
            .arg(lease->toText())
            .arg(ex.what());
        return;
    }
956
    // Create NameChangeRequest
957
958
    NameChangeRequest ncr(chg_type, lease->fqdn_fwd_, lease->fqdn_rev_,
                          lease->hostname_, lease->addr_.toText(),
959
960
                          dhcid, lease->cltt_ + lease->valid_lft_,
                          lease->valid_lft_);
961
962
963
964
    // And queue it.
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUEUE_NCR)
        .arg(chg_type == CHG_ADD ? "add" : "remove")
        .arg(ncr.toText());
965
966
967
    name_change_reqs_.push(ncr);
}

968
969
970
971
972
973
974
975
976
void
Dhcpv4Srv::sendNameChangeRequests() {
    while (!name_change_reqs_.empty()) {
        // @todo Once next NameChangeRequest is picked from the queue
        // we should send it to the b10-dhcp_ddns module. Currently we
        // just drop it.
        name_change_reqs_.pop();
    }
}
977

978
979
void
Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996

    // We need to select a subnet the client is connected in.
    Subnet4Ptr subnet = selectSubnet(question);
    if (!subnet) {
        // This particular client is out of luck today. We do not have
        // information about the subnet he is connected to. This likely means
        // misconfiguration of the server (or some relays). We will continue to
        // process this message, but our response will be almost useless: no
        // addresses or prefixes, no subnet specific configuration etc. The only
        // thing this client can get is some global information (like DNS
        // servers).

        // perhaps this should be logged on some higher level? This is most likely
        // configuration bug.
        LOG_ERROR(dhcp4_logger, DHCP4_SUBNET_SELECTION_FAILED)
            .arg(question->getRemoteAddr().toText())
            .arg(serverReceivedPacketName(question->getType()));
997
        answer->setType(DHCPNAK);
998
999
1000
        answer->setYiaddr(IOAddress("0.0.0.0"));
        return;
    }
For faster browsing, not all history is shown. View entire blame