dhcp4_srv.cc 90.1 KB
Newer Older
1
// Copyright (C) 2011-2015 Internet Systems Consortium, Inc. ("ISC")
2
3
4
5
6
7
8
9
10
11
12
13
14
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

15
#include <config.h>
16
#include <asiolink/io_address.h>
17
#include <dhcp/dhcp4.h>
18
19
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
20
#include <dhcp/iface_mgr.h>
21
#include <dhcp/option4_addrlst.h>
22
#include <dhcp/option_int.h>
23
#include <dhcp/option_int_array.h>
24
#include <dhcp/option_vendor.h>
25
#include <dhcp/option_string.h>
26
#include <dhcp/pkt4.h>
27
#include <dhcp/docsis3_option_defs.h>
28
29
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
30
31
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
32
#include <dhcpsrv/cfgmgr.h>
33
#include <dhcpsrv/cfg_subnets4.h>
34
35
36
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
#include <dhcpsrv/subnet.h>
37
#include <dhcpsrv/subnet_selector.h>
38
#include <dhcpsrv/utils.h>
39
#include <dhcpsrv/utils.h>
40
#include <hooks/callout_handle.h>
41
#include <hooks/hooks_log.h>
42
#include <hooks/hooks_manager.h>
43
#include <util/strutil.h>
44
#include <stats/stats_mgr.h>
45

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

#include <iomanip>

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

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

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

// Declare a Hooks object. As this is outside any function or method, it
// will be instantiated (and the constructor run) when the module is loaded.
// As a result, the hook indexes will be defined before any method in this
// module is called.
85
Dhcp4Hooks Hooks;
86

87
88
89
namespace isc {
namespace dhcp {

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

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

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

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

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

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

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

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

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

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

    // If src/dest HW addresses are used by the packet filtering class
    // we need to copy them as well. There is a need to check that the
    // address being set is not-NULL because an attempt to set the NULL
    // HW would result in exception. If these values are not set, the
    // the default HW addresses (zeroed) should be generated by the
    // packet filtering class when creating Ethernet header for
    // outgoing packet.
    HWAddrPtr src_hw_addr = query_->getLocalHWAddr();
    if (src_hw_addr) {
        resp_->setLocalHWAddr(src_hw_addr);
    }
    HWAddrPtr dst_hw_addr = query_->getRemoteHWAddr();
    if (dst_hw_addr) {
        resp_->setRemoteHWAddr(dst_hw_addr);
    }

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

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

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

199
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
200
    try {
201
202
203
        // Port 0 is used for testing purposes where we don't open broadcast
        // capable sockets. So, set the packet filter handling direct traffic
        // only if we are in non-test mode.
204
        if (port) {
205
206
207
208
209
210
211
212
            // First call to instance() will create IfaceMgr (it's a singleton)
            // it may throw something if things go wrong.
            // The 'true' value of the call to setMatchingPacketFilter imposes
            // that IfaceMgr will try to use the mechanism to respond directly
            // to the client which doesn't have address assigned. This capability
            // may be lacking on some OSes, so there is no guarantee that server
            // will be able to respond directly.
            IfaceMgr::instance().setMatchingPacketFilter(direct_response_desired);
213
        }
214

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

219
220
221
222
223
224
225
        // Register hook points
        hook_index_pkt4_receive_   = Hooks.hook_index_pkt4_receive_;
        hook_index_subnet4_select_ = Hooks.hook_index_subnet4_select_;
        hook_index_pkt4_send_      = Hooks.hook_index_pkt4_send_;

        /// @todo call loadLibraries() when handling configuration changes

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

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

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

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

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

    Subnet4Ptr subnet;

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

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

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

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

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

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

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

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

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

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

310
    return (subnet);
311
312
}

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

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

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

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

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

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

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

376
377
378
        // Handle next signal received by the process. It must be called after
        // an attempt to receive a packet to properly handle server shut down.
        // The SIGTERM or SIGINT will be received prior to, or during execution
Francis Dupont's avatar
Francis Dupont committed
379
380
381
382
383
384
385
        // of select() (select is invoked by receivePacket()). When that
        // happens, select will be interrupted. The signal handler will be
        // invoked immediately after select(). The handler will set the
        // shutdown flag and cause the process to terminate before the next
        // select() function is called. If the function was called before
        // receivePacket the process could wait up to the duration of timeout
        // of select() to terminate.
386
387
        handleSignal();

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

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

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

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

410
411
412
413
414
415
416
417
418
        // In order to parse the DHCP options, the server needs to use some
        // configuration information such as: existing option spaces, option
        // definitions etc. This is the kind of information which is not
        // available in the libdhcp, so we need to supply our own implementation
        // of the option parsing function here, which would rely on the
        // configuration data.
        query->setCallback(boost::bind(&Dhcpv4Srv::unpackOptions, this,
                                       _1, _2, _3));

419
420
421
        bool skip_unpack = false;

        // The packet has just been received so contains the uninterpreted wire
422
        // data; execute callouts registered for buffer4_receive.
423
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
424
425
426
427
428
429
430
431
432
            CalloutHandlePtr callout_handle = getCalloutHandle(query);

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

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

            // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
433
434
            HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                       *callout_handle);
435
436
437
438
439
440

            // Callouts decided to skip the next processing step. The next
            // processing step would to parse the packet, so skip at this
            // stage means that callouts did the parsing already, so server
            // should skip parsing.
            if (callout_handle->getSkip()) {
441
                LOG_DEBUG(hooks_logger, DBG_DHCP4_DETAIL, DHCP4_HOOK_BUFFER_RCVD_SKIP)
442
443
444
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
445
446
447
448
449
450
451
452
453
                skip_unpack = true;
            }

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

        // Unpack the packet information unless the buffer4_receive callouts
        // indicated they did it
        if (!skip_unpack) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
454
            try {
455
456
457
458
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_UNPACK)
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface());
Tomek Mrugalski's avatar
Tomek Mrugalski committed
459
460
                query->unpack();
            } catch (const std::exception& e) {
461
                // Failed to parse the packet.
462
463
                LOG_DEBUG(bad_packet_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_DROP_0001)
464
465
466
                    .arg(query->getRemoteAddr().toText())
                    .arg(query->getLocalAddr().toText())
                    .arg(query->getIface())
467
                    .arg(e.what());
468
469
                continue;
            }
470
        }
471

472
473
474
        // Update statistics accordingly for received packet.
        processStatsReceived(query);

Tomek Mrugalski's avatar
Tomek Mrugalski committed
475
476
477
        // 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.
478
479
        classifyPacket(query);

480
481
482
        // 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)) {
483
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop", 1ul);
484
            continue;
485
        }
486

487
        // We have sanity checked (in accept() that the Message Type option
488
489
        // exists, so we can safely get it here.
        int type = query->getType();
490
        LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC_DATA, DHCP4_PACKET_RECEIVED)
491
            .arg(query->getLabel())
492
            .arg(query->getName())
493
            .arg(type)
494
495
            .arg(query->getRemoteAddr())
            .arg(query->getLocalAddr())
496
            .arg(query->getIface());
497
498
        LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
            .arg(query->getLabel())
499
500
            .arg(query->toText());

Tomek Mrugalski's avatar
Tomek Mrugalski committed
501
        // Let's execute all callouts registered for pkt4_receive
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
        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()) {
519
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP)
520
                    .arg(query->getLabel());
521
522
                continue;
            }
523

524
525
            callout_handle->getArgument("query4", query);
        }
526

527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
        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:
549
                rsp = processInform(query);
550
551
552
553
554
555
556
                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.
                ;
557
            }
558
559
        } catch (const isc::Exception& e) {

560
561
562
563
564
565
            // 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.)
566
567
568
569
            LOG_DEBUG(bad_packet_logger, DBG_DHCP4_BASIC,
                      DHCP4_PACKET_DROP_0007)
                .arg(query->getLabel())
                .arg(e.what());
570
        }
571

572
573
574
        if (!rsp) {
            continue;
        }
575

576

577
578
        // Specifies if server should do the packing
        bool skip_pack = false;
579

Tomek Mrugalski's avatar
Tomek Mrugalski committed
580
        // Execute all callouts registered for pkt4_send
581
582
        if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
583

584
585
            // Delete all previous arguments
            callout_handle->deleteAllArguments();
586

587
588
            // Clear skip flag if it was set in previous callouts
            callout_handle->setSkip(false);
589

590
591
            // Set our response
            callout_handle->setArgument("response4", rsp);
592

593
594
595
            // Call all installed callouts
            HooksManager::callCallouts(hook_index_pkt4_send_,
                                       *callout_handle);
596

597
598
599
600
            // 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()) {
601
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP)
602
                    .arg(query->getLabel());
603
604
605
606
607
608
                skip_pack = true;
            }
        }

        if (!skip_pack) {
            try {
609
610
                LOG_DEBUG(options_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_PACK)
                    .arg(rsp->getLabel());
611
612
                rsp->pack();
            } catch (const std::exception& e) {
613
614
                LOG_ERROR(options_logger, DHCP4_PACKET_PACK_FAIL)
                    .arg(rsp->getLabel())
615
616
617
618
619
620
621
622
                    .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
623
            // Let's execute all callouts registered for buffer4_send
624
            if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
625
                CalloutHandlePtr callout_handle = getCalloutHandle(query);
626

627
628
                // Delete previously set arguments
                callout_handle->deleteAllArguments();
629

630
631
                // Pass incoming packet as argument
                callout_handle->setArgument("response4", rsp);
632

633
                // Call callouts
Tomek Mrugalski's avatar
Tomek Mrugalski committed
634
635
                HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                           *callout_handle);
636

637
638
639
640
                // 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()) {
641
                    LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
642
643
                              DHCP4_HOOK_BUFFER_SEND_SKIP)
                        .arg(rsp->getLabel());
644
                    continue;
645
                }
646
647

                callout_handle->getArgument("response4", rsp);
648
            }
649

650
            LOG_DEBUG(packet_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND)
651
                .arg(rsp->getLabel())
652
                .arg(rsp->getName())
653
654
655
656
657
658
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->getLocalAddr())
                .arg(rsp->getLocalPort())
                .arg(rsp->getRemoteAddr())
                .arg(rsp->getRemotePort())
                .arg(rsp->getIface());
659
660

            LOG_DEBUG(packet_logger, DBG_DHCP4_DETAIL_DATA,
661
                      DHCP4_RESPONSE_DATA)
662
663
664
665
                .arg(rsp->getLabel())
                .arg(rsp->getName())
                .arg(static_cast<int>(rsp->getType()))
                .arg(rsp->toText());
666
            sendPacket(rsp);
667
668
669
670

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

671
        } catch (const std::exception& e) {
672
673
            LOG_ERROR(packet_logger, DHCP4_PACKET_SEND_FAIL)
                .arg(rsp->getLabel())
674
                .arg(e.what());
675
        }
676
677
678
679
680
    }

    return (true);
}

681
string
682
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
    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());
699
700
}

701
isc::dhcp_ddns::D2Dhcid
702
703
704
705
706
707
708
709
710
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");

711
712
    }

713
714
715
716
717
718
719
720
721
    // 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);
722

723
724
725
    } catch (const Exception& ex) {
        isc_throw(DhcidComputeError, "unable to compute DHCID because the"
                  " hostname: " << lease->hostname_ << " is invalid");
726
727

    }
728
729
730

    // Prefer client id to HW address to compute DHCID. If Client Id is
    // NULL, use HW address.
731
    try {
732
733
734
735
        if (lease->client_id_) {
            return (D2Dhcid(lease->client_id_->getClientId(), fqdn_wire));

        } else {
736
            return (D2Dhcid(lease->hwaddr_, fqdn_wire));
737
        }
738
    } catch (const Exception& ex) {
739
740
        isc_throw(DhcidComputeError, "unable to compute DHCID: "
                  << ex.what());
741

742
    }
743
744
745

}

746
void
747
Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) {
748
749
750
    // 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.
751
752
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
753
754
755
    OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                           ex.getResponse()->getLocalAddr()));
    ex.getResponse()->addOption(opt_srvid);
756
757
}

758
void
759
Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) {
760
761
    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
762
    Subnet4Ptr subnet = ex.getContext()->subnet_;
763
764
765
766
767
768
769
    // 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;
    }
770

771
772
    Pkt4Ptr query = ex.getQuery();

773
774
775
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
776
        OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
777
778
779
780
781
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
782

783
784
    Pkt4Ptr resp = ex.getResponse();

785
786
787
788
789
790
    // 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) {
791
        if (!resp->getOption(*opt)) {
792
            OptionDescriptor desc = subnet->getCfgOption()->get("dhcp4", *opt);
793
            if (desc.option_) {
794
                resp->addOption(desc.option_);
795
            }
796
797
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
798
}
799

800
void
801
Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) {
802
    // Get the configured subnet suitable for the incoming packet.
803
    Subnet4Ptr subnet = ex.getContext()->subnet_;
804
805
806
807
808
809
810
811
812
813
    // 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
814
815
    boost::shared_ptr<OptionVendor> vendor_req = boost::dynamic_pointer_cast<
        OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS));
816
817
818
819
820
821
822
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
823
824
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
825
826
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
827
828
829
830
831
832
833
834
835
836

    // 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;
837
    const std::vector<uint8_t>& requested_opts = oro->getValues();
838

Tomek Mrugalski's avatar
Tomek Mrugalski committed
839
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
840
         code != requested_opts.end(); ++code) {
841
        if  (!vendor_rsp->getOption(*code)) {
842
843
            OptionDescriptor desc = subnet->getCfgOption()->get(vendor_id,
                                                                *code);
844
845
            if (desc.option_) {
                vendor_rsp->addOption(desc.option_);
846
847
                added = true;
            }
848
849
        }

850
        if (added) {
851
            ex.getResponse()->addOption(vendor_rsp);
852
853
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
854
}
855

856

857
void
858
Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) {
859
860
861
862
863
864
    // 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 };
865

866
867
868
869
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
870
    Subnet4Ptr subnet = ex.getContext()->subnet_;
871
872
873
874
    if (!subnet) {
        return;
    }

875
876
    Pkt4Ptr resp = ex.getResponse();

877
878
879
    // 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) {
880
        OptionPtr opt = resp->getOption(required_options[i]);
881
882
        if (!opt) {
            // Check whether option has been configured.
883
884
            OptionDescriptor desc = subnet->getCfgOption()->
                get("dhcp4", required_options[i]);
885
            if (desc.option_) {
886
                resp->addOption(desc.option_);
887
888
889
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
890
}
891

892
void
893
Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) {
894
895
896
    // 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.
897
    try {
898
        Pkt4Ptr resp = ex.getResponse();
899
        Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<Option4ClientFqdn>
900
            (ex.getQuery()->getOption(DHO_FQDN));
901
        if (fqdn) {
902
            LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_FQDN_PROCESS)
903
                .arg(ex.getQuery()->getLabel());
904
            processClientFqdnOption(ex);
905
906

        } else {
907
            OptionStringPtr hostname = boost::dynamic_pointer_cast<OptionString>
908
                (ex.getQuery()->getOption(DHO_HOST_NAME));
909
            if (hostname) {
910
                LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_HOSTNAME_PROCESS)
911
                    .arg(ex.getQuery()->getLabel());
912
                processHostnameOption(ex);
913
914
            }
        }
915
    } catch (const Exception& e) {
916
917
918
919
920
921
922
923
        // 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.
924
        LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL)
925
926
            .arg(ex.getQuery()->getLabel())
            .arg(e.what());
927
928
929
930
    }
}

void
931
Dhcpv4Srv::processClientFqdnOption(Dhcpv4Exchange& ex) {
932
933
934
935
    // Obtain the FQDN option from the client's message.
    Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast<
        Option4ClientFqdn>(ex.getQuery()->getOption(DHO_FQDN));

936
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_FQDN_DATA)
937
938
939
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn->toText());

940
941
942
943
    // Create the DHCPv4 Client FQDN Option to be included in the server's
    // response to a client.
    Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));

944
945
946
947
    // 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);
948

949
950
951
    // Carry over the client's E flag.
    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E,
                       fqdn->getFlag(Option4ClientFqdn::FLAG_E));
952

953
    if (ex.getContext()->host_ && !ex.getContext()->host_->getHostname().empty()) {
954
955
956
        D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
        fqdn_resp->setDomainName(d2_mgr.qualifyName(ex.getContext()->host_->getHostname(),
                                                    true), Option4ClientFqdn::FULL);
957

958
959
960
961
962
    } 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);
    }
963
964
965
966
967
968
969
970
971
972

    // 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
973
    // If we don't store the option in the response message, we will have to
974
975
    // propagate it in the different way to the functions which acquire the
    // lease. This would require modifications to the API of this class.
976
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_RESPONSE_FQDN_DATA)
977
978
        .arg(ex.getQuery()->getLabel())
        .arg(fqdn_resp->toText());
979
    ex.getResponse()->addOption(fqdn_resp);
980
981
982
}

void
983
Dhcpv4Srv::processHostnameOption(Dhcpv4Exchange& ex) {
984
985
986
987
    // Obtain the Hostname option from the client's message.
    OptionStringPtr opt_hostname = boost::dynamic_pointer_cast<OptionString>
        (ex.getQuery()->getOption(DHO_HOST_NAME));

988
    LOG_DEBUG(ddns_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_HOSTNAME_DATA)
989
990
991
        .arg(ex.getQuery()->getLabel())
        .arg(opt_hostname->getValue());

992
993
994
    // Fetch D2 configuration.
    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();

995
    // Do nothing if the DNS updates are disabled.
996
    if (!d2_mgr.ddnsEnabled()) {
997
998
999
        return;
    }

1000
    std::string hostname = isc::util::str::trim(opt_hostname->getValue());
For faster browsing, not all history is shown. View entire blame