dhcp4_srv.h 33.1 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
15
16
17
//
// 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.

#ifndef DHCPV4_SRV_H
#define DHCPV4_SRV_H

18
#include <dhcp/dhcp4.h>
19
20
#include <dhcp/pkt4.h>
#include <dhcp/option.h>
21
#include <dhcp/option_string.h>
22
#include <dhcp/option4_client_fqdn.h>
23
#include <dhcp/option_custom.h>
24
#include <dhcp_ddns/ncr_msg.h>
25
#include <dhcpsrv/d2_client_mgr.h>
26
27
#include <dhcpsrv/subnet.h>
#include <dhcpsrv/alloc_engine.h>
28
#include <hooks/callout_handle.h>
29
#include <dhcpsrv/daemon.h>
30
31
32

#include <boost/noncopyable.hpp>

33
#include <iostream>
34
#include <queue>
35

36
37
38
39
// Undefine the macro OPTIONAL which is defined in some operating
// systems but conflicts with a member of the RequirementLevel enum in
// the server class.

40
41
42
43
#ifdef OPTIONAL
#undef OPTIONAL
#endif

44
45
namespace isc {
namespace dhcp {
46

47
48
49
50
51
52
53
/// @brief Exception thrown when DHCID computation failed.
class DhcidComputeError : public isc::Exception {
public:
    DhcidComputeError(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what) { };
};

54
55
56
57
58
/// @brief DHCPv4 message exchange.
///
/// This class represents the DHCPv4 message exchange. The message exchange
/// consists of the single client message, server response to this message
/// and the mechanisms to generate the server's response. The server creates
59
/// the instance of the @c Dhcpv4Exchange for each inbound message that it
60
61
/// accepts for processing.
///
62
/// The use of the @c Dhcpv4Exchange object as a central repository of
63
64
65
66
67
68
69
70
71
72
/// information about the message exchange simplifies the API of the
/// @c Dhcpv4Srv class.
///
/// Another benefit of using this class is that different methods of the
/// @c Dhcpv4Srv may share information. For example, the constructor of this
/// class selects the subnet and multiple methods of @c Dhcpv4Srv use this
/// subnet, without the need to select it again.
///
/// @todo This is the initial version of this class. In the future a lot of
/// code from the @c Dhcpv4Srv class will be migrated here.
73
class Dhcpv4Exchange {
74
75
76
77
78
79
80
81
82
83
84
85
public:
    /// @brief Constructor.
    ///
    /// The constructor selects the subnet for the query and checks for the
    /// static host reservations for the client which has sent the message.
    /// The information about the reservations is stored in the
    /// @c AllocEngine::ClientContext4 object, which can be obtained by
    /// calling the @c getContext.
    ///
    /// @param alloc_engine Pointer to the instance of the Allocation Engine
    /// used by the server.
    /// @param query Pointer to the client message.
86
87
88
    /// @param subnet Pointer to the subnet to which the client belongs.
    Dhcpv4Exchange(const AllocEnginePtr& alloc_engine, const Pkt4Ptr& query,
                   const Subnet4Ptr& subnet);
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120

    /// @brief Initializes the instance of the response message.
    ///
    /// The type of the response depends on the type of the query message.
    /// For the DHCPDISCOVER the DHCPOFFER is created. For the DHCPREQUEST
    /// and DHCPINFORM the DHCPACK is created. For the DHCPRELEASE the
    /// response is not initialized.
    void initResponse();

    /// @brief Returns the pointer to the query from the client.
    Pkt4Ptr getQuery() const {
        return (query_);
    }

    /// @brief Returns the pointer to the server's response.
    ///
    /// The returned pointer is NULL if the query type is DHCPRELEASE or DHCPDECLINE.
    Pkt4Ptr getResponse() const {
        return (resp_);
    }

    /// @brief Removes the response message by resetting the pointer to NULL.
    void deleteResponse() {
        resp_.reset();
    }

    /// @brief Returns the copy of the context for the Allocation engine.
    AllocEngine::ClientContext4Ptr getContext() const {
        return (context_);
    }

private:
121
122
123
124
125
126
127
128
129
130
131
132

    /// @brief Copies default parameters from client's to server's message
    ///
    /// Some fields are copied from client's message into server's response,
    /// e.g. client HW address, number of hops, transaction-id etc.
    ///
    /// @warning This message is called internally by @c initResponse and
    /// thus it doesn't check if the resp_ value has been initialized. The
    /// calling method is responsible for making sure that @c resp_ is
    /// not NULL.
    void copyDefaultFields();

133
134
135
136
137
138
139
140
141
142
    /// @brief Pointer to the allocation engine used by the server.
    AllocEnginePtr alloc_engine_;
    /// @brief Pointer to the DHCPv4 message sent by the client.
    Pkt4Ptr query_;
    /// @brief Pointer to the DHCPv4 message to be sent to the client.
    Pkt4Ptr resp_;
    /// @brief Context for use with allocation engine.
    AllocEngine::ClientContext4Ptr context_;
};

143
144
/// @brief Type representing the pointer to the @c Dhcpv4Exchange.
typedef boost::shared_ptr<Dhcpv4Exchange> Dhcpv4ExchangePtr;
145
146


147
148
149
150
151
152
153
154
/// @brief DHCPv4 server service.
///
/// This singleton class represents DHCPv4 server. It contains all
/// top-level methods and routines necessary for server operation.
/// In particular, it instantiates IfaceMgr, loads or generates DUID
/// that is going to be used as server-identifier, receives incoming
/// packets, processes them, manages leases assignment and generates
/// appropriate responses.
155
156
///
/// This class does not support any controlling mechanisms directly.
157
/// See the derived \ref ControlledDhcpv4Srv class for support for
158
/// command and configuration updates over msgq.
159
class Dhcpv4Srv : public Daemon {
160

161
public:
162
163
164
165
166
167
168
169

    /// @brief defines if certain option may, must or must not appear
    typedef enum {
        FORBIDDEN,
        MANDATORY,
        OPTIONAL
    } RequirementLevel;

170
171
    /// @brief Default constructor.
    ///
172
    /// Instantiates necessary services, required to run DHCPv4 server.
173
174
    /// In particular, creates IfaceMgr that will be responsible for
    /// network interaction. Will instantiate lease manager, and load
Tomek Mrugalski's avatar
Tomek Mrugalski committed
175
176
    /// old or create new DUID. It is possible to specify alternate
    /// port on which DHCPv4 server will listen on. That is mostly useful
177
178
    /// for testing purposes. The Last two arguments of the constructor
    /// should be left at default values for normal server operation.
Marcin Siodelski's avatar
Marcin Siodelski committed
179
180
181
    /// They should be set to 'false' when creating an instance of this
    /// class for unit testing because features they enable require
    /// root privileges.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
182
183
    ///
    /// @param port specifies port number to listen on
184
    /// @param use_bcast configure sockets to support broadcast messages.
185
186
    /// @param direct_response_desired specifies if it is desired to
    /// use direct V4 traffic.
187
    Dhcpv4Srv(uint16_t port = DHCP4_SERVER_PORT,
188
189
              const bool use_bcast = true,
              const bool direct_response_desired = true);
190

191
    /// @brief Destructor. Used during DHCPv4 service shutdown.
192
    virtual ~Dhcpv4Srv();
193

194
    /// @brief returns Kea version on stdout and exit.
195
    /// redeclaration/redefinition. @ref Daemon::getVersion()
196
197
    static std::string getVersion(bool extended);
 
198
199
200
201
    /// @brief Main server processing loop.
    ///
    /// Main server processing loop. Receives incoming packets, verifies
    /// their correctness, generates appropriate answer (if needed) and
Francis Dupont's avatar
Francis Dupont committed
202
    /// transmits responses.
203
204
205
206
207
    ///
    /// @return true, if being shut down gracefully, fail if experienced
    ///         critical error.
    bool run();

208
    /// @brief Instructs the server to shut down.
209
210
    void shutdown();

211
212
213
214
215
216
217
    ///
    /// @name Public accessors returning values required to (re)open sockets.
    ///
    //@{
    ///
    /// @brief Get UDP port on which server should listen.
    ///
218
219
220
    /// Typically, server listens on UDP port number 67. Other ports are used
    /// for testing purposes only.
    ///
221
222
223
224
225
226
227
228
229
230
231
232
233
234
    /// @return UDP port on which server should listen.
    uint16_t getPort() const {
        return (port_);
    }

    /// @brief Return bool value indicating that broadcast flags should be set
    /// on sockets.
    ///
    /// @return A bool value indicating that broadcast should be used (if true).
    bool useBroadcast() const {
        return (use_bcast_);
    }
    //@}

235
236
    /// @brief Starts DHCP_DDNS client IO if DDNS updates are enabled.
    ///
237
    /// If updates are enabled, it instructs the D2ClientMgr singleton to
238
    /// enter send mode.  If D2ClientMgr encounters errors it may throw
239
    /// D2ClientError. This method does not catch exceptions.
240
241
    void startD2();

242
243
244
245
    /// @brief Stops DHCP_DDNS client IO if DDNS updates are enabled.
    ///
    /// If updates are enabled, it instructs the D2ClientMgr singleton to
    /// leave send mode.  If D2ClientMgr encounters errors it may throw
246
    /// D2ClientError. This method does not catch exceptions.
247
248
    void stopD2();

249
250
    /// @brief Implements the error handler for DHCP_DDNS IO errors
    ///
251
    /// Invoked when a NameChangeRequest send to kea-dhcp-ddns completes with
252
253
254
255
256
257
258
259
260
261
262
263
264
265
    /// a failed status.  These are communications errors, not data related
    /// failures.
    ///
    /// This method logs the failure and then suspends all further updates.
    /// Updating can only be restored by reconfiguration or restarting the
    /// server.  There is currently no retry logic so the first IO error that
    /// occurs will suspend updates.
    /// @todo We may wish to make this more robust or sophisticated.
    ///
    /// @param result Result code of the send operation.
    /// @param ncr NameChangeRequest which failed to send.
    virtual void d2ClientErrorHandler(const dhcp_ddns::
                                      NameChangeSender::Result result,
                                      dhcp_ddns::NameChangeRequestPtr& ncr);
266
protected:
267

268
269
270
271
272
273
274
    /// @name Functions filtering and sanity-checking received messages.
    ///
    /// @todo These functions are supposed to be moved to a new class which
    /// will manage different rules for accepting and rejecting messages.
    /// Perhaps ticket #3116 is a good opportunity to do it.
    ///
    //@{
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
    /// @brief Checks whether received message should be processed or discarded.
    ///
    /// This function checks whether received message should be processed or
    /// discarded. It should be called on the beginning of message processing
    /// (just after the message has been decoded). This message calls a number
    /// of other functions which check whether message should be processed,
    /// using different criteria.
    ///
    /// This function should be extended when new criteria for accepting
    /// received message have to be implemented. This function is meant to
    /// aggregate all early filtering checks on the received message. By having
    /// a single function like this, we are avoiding bloat of the server's main
    /// loop.
    ///
    /// @warning This function should remain exception safe.
    ///
    /// @param query Received message.
    ///
    /// @return true if the message should be further processed, or false if
    /// the message should be discarded.
    bool accept(const Pkt4Ptr& query) const;

    /// @brief Check if a message sent by directly connected client should be
Francis Dupont's avatar
Francis Dupont committed
298
    /// accepted or discarded.
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
    ///
    /// This function checks if the received message is from directly connected
    /// client. If it is, it checks that it should be processed or discarded.
    ///
    /// Note that this function doesn't validate all addresses being carried in
    /// the message. The primary purpose of this function is to filter out
    /// direct messages in the local network for which there is no suitable
    /// subnet configured. For example, this function accepts unicast messages
    /// because unicasts may be used by clients located in remote networks to
    /// to renew existing leases. If their notion of address is wrong, the
    /// server will have to sent a NAK, instead of dropping the message.
    /// Detailed validation of such messages is performed at later stage of
    /// processing.
    ///
    /// This function accepts the following messages:
    /// - all valid relayed messages,
    /// - all unicast messages,
316
317
318
    /// - all broadcast messages except DHCPINFORM received on the interface
    /// for which the suitable subnet exists (is configured).
    /// - all DHCPINFORM messages with source address or ciaddr set.
319
    ///
320
    /// @param query Message sent by a client.
321
322
323
    ///
    /// @return true if message is accepted for further processing, false
    /// otherwise.
324
325
326
327
328
    bool acceptDirectRequest(const Pkt4Ptr& query) const;

    /// @brief Check if received message type is valid for the server to
    /// process.
    ///
Francis Dupont's avatar
Francis Dupont committed
329
330
331
    /// This function checks that the received message type belongs to
    /// the range of types recognized by the server and that the
    /// message of this type should be processed by the server.
332
333
334
335
336
337
338
339
340
341
342
343
344
    ///
    /// The messages types accepted for processing are:
    /// - Discover
    /// - Request
    /// - Release
    /// - Decline
    /// - Inform
    ///
    /// @param query Message sent by a client.
    ///
    /// @return true if message is accepted for further processing, false
    /// otherwise.
    bool acceptMessageType(const Pkt4Ptr& query) const;
345

346
347
348
349
350
351
352
353
354
355
356
357
358
359
    /// @brief Verifies if the server id belongs to our server.
    ///
    /// This function checks if the server identifier carried in the specified
    /// DHCPv4 message belongs to this server. If the server identifier option
    /// is absent or the value carried by this option is equal to one of the
    /// server identifiers used by the server, the true is returned. If the
    /// server identifier option is present, but it doesn't match any server
    /// identifier used by this server, the false value is returned.
    ///
    /// @param pkt DHCPv4 message which server identifier is to be checked.
    ///
    /// @return true, if the server identifier is absent or matches one of the
    /// server identifiers that the server is using; false otherwise.
    bool acceptServerId(const Pkt4Ptr& pkt) const;
360
    //@}
361

362
    /// @brief Verifies if specified packet meets RFC requirements
363
364
365
366
    ///
    /// Checks if mandatory option is really there, that forbidden option
    /// is not there, and that client-id or server-id appears only once.
    ///
367
    /// @param query Pointer to the client's message.
368
369
    /// @param serverid expectation regarding server-id option
    /// @throw RFCViolation if any issues are detected
370
    static void sanityCheck(const Pkt4Ptr& query, RequirementLevel serverid);
371

372
373
374
375
376
377
    /// @brief Processes incoming DISCOVER and returns response.
    ///
    /// Processes received DISCOVER message and verifies that its sender
    /// should be served. In particular, a lease is selected and sent
    /// as an offer to a client if it should be served.
    ///
378
    /// @param discover DISCOVER message received from client
379
380
    ///
    /// @return OFFER message or NULL
381
    Pkt4Ptr processDiscover(Pkt4Ptr& discover);
382
383
384
385
386

    /// @brief Processes incoming REQUEST and returns REPLY response.
    ///
    /// Processes incoming REQUEST message and verifies that its sender
    /// should be served. In particular, verifies that requested lease
Tomek Mrugalski's avatar
Tomek Mrugalski committed
387
    /// is valid, not expired, not reserved, not used by other client and
388
389
    /// that requesting client is allowed to use it.
    ///
390
    /// Returns ACK message, NAK message, or NULL
391
392
393
    ///
    /// @param request a message received from client
    ///
394
    /// @return ACK or NAK message
395
    Pkt4Ptr processRequest(Pkt4Ptr& request);
396

397
    /// @brief Processes incoming DHCPRELEASE messages.
398
399
400
401
402
    ///
    /// In DHCPv4, server does not respond to RELEASE messages, therefore
    /// this function does not return anything.
    ///
    /// @param release message received from client
403
    void processRelease(Pkt4Ptr& release);
404

Tomek Mrugalski's avatar
Tomek Mrugalski committed
405
406
407
    /// @brief Process incoming DHCPDECLINE messages.
    ///
    /// This method processes incoming DHCPDECLINE. In particular, it extracts
Shawn Routhier's avatar
Shawn Routhier committed
408
    /// Requested IP Address option, checks that the address really belongs to
Tomek Mrugalski's avatar
Tomek Mrugalski committed
409
    /// the client and if it does, calls @ref declineLease.
410
411
    ///
    /// @param decline message received from client
412
    void processDecline(Pkt4Ptr& decline);
413

414
    /// @brief Processes incoming DHCPINFORM messages.
415
    ///
416
    /// @param inform message received from client
417
418
    ///
    /// @return DHCPACK to be sent to the client.
419
    Pkt4Ptr processInform(Pkt4Ptr& inform);
420

Tomek Mrugalski's avatar
Tomek Mrugalski committed
421
422
423
    /// @brief Appends options requested by client.
    ///
    /// This method assigns options that were requested by client
Tomek Mrugalski's avatar
Tomek Mrugalski committed
424
    /// (sent in PRL) or are enforced by server.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
425
    ///
426
427
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
428
    void appendRequestedOptions(Dhcpv4Exchange& ex);
Tomek Mrugalski's avatar
Tomek Mrugalski committed
429

430
431
432
433
434
435
436
437
    /// @brief Appends requested vendor options as requested by client.
    ///
    /// This method is similar to \ref appendRequestedOptions(), but uses
    /// vendor options. The major difference is that vendor-options use
    /// its own option spaces (there may be more than one distinct set of vendor
    /// options, each with unique vendor-id). Vendor options are requested
    /// using separate options within their respective vendor-option spaces.
    ///
438
439
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
440
    void appendRequestedVendorOptions(Dhcpv4Exchange& ex);
441

Tomek Mrugalski's avatar
Tomek Mrugalski committed
442
443
    /// @brief Assigns a lease and appends corresponding options
    ///
Francis Dupont's avatar
Francis Dupont committed
444
    /// This method chooses the most appropriate lease for requesting
Tomek Mrugalski's avatar
Tomek Mrugalski committed
445
446
447
    /// client and assigning it. Options corresponding to the lease
    /// are added to specific message.
    ///
448
449
450
451
452
453
454
455
    /// This method may reset the pointer to the response in the @c ex object
    /// to indicate that the response should not be sent to the client.
    /// The caller must check if the response is is null after calling
    /// this method.
    ///
    /// The response type in the @c ex object may be set to DHCPACK or DHCPNAK.
    ///
    /// @param ex DHCPv4 exchange holding the client's message to be checked.
456
    void assignLease(Dhcpv4Exchange& ex);
457

458
459
460
    /// @brief Append basic options if they are not present.
    ///
    /// This function adds the following basic options if they
461
    /// are not yet added to the response message:
462
463
464
465
466
    /// - Subnet Mask,
    /// - Router,
    /// - Name Server,
    /// - Domain Name.
    ///
467
    /// @param ex DHCPv4 exchange holding the client's message to be checked.
468
    void appendBasicOptions(Dhcpv4Exchange& ex);
469

470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
    /// @brief Processes Client FQDN and Hostname Options sent by a client.
    ///
    /// Client may send Client FQDN or Hostname option to communicate its name
    /// to the server. Server may use this name to perform DNS update for the
    /// lease being assigned to a client. If server takes responsibility for
    /// updating DNS for a client it may communicate it by sending the Client
    /// FQDN or Hostname %Option back to the client. Server select a different
    /// name than requested by a client to update DNS. In such case, the server
    /// stores this different name in its response.
    ///
    /// Client should not send both Client FQDN and Hostname options. However,
    /// if client sends both options, server should prefer Client FQDN option
    /// and ignore the Hostname option. If Client FQDN option is not present,
    /// the Hostname option is processed.
    ///
    /// The Client FQDN %Option is processed by this function as described in
    /// RFC4702.
    ///
    /// In response to a Hostname %Option sent by a client, the server may send
    /// Hostname option with the same or different hostname. If different
    /// hostname is sent, it is an indication to the client that server has
    /// overridden the client's preferred name and will rather use this
    /// different name to update DNS. However, since Hostname option doesn't
    /// carry an information whether DNS update will be carried by the server
    /// or not, the client is responsible for checking whether DNS update
    /// has been performed.
    ///
    /// After successful processing options stored in the first parameter,
    /// this function may add Client FQDN or Hostname option to the response
    /// message. In some cases, server may cease to add any options to the
    /// response, i.e. when server doesn't support DNS updates.
    ///
502
503
504
    /// This function does not throw. It simply logs the debug message if the
    /// processing of the FQDN or Hostname failed.
    ///
505
506
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
507
    void processClientName(Dhcpv4Exchange& ex);
508

509
510
511
512
513
514
515
516
    /// @brief this is a prefix added to the contend of vendor-class option
    ///
    /// If incoming packet has a vendor class option, its content is
    /// prepended with this prefix and then interpreted as a class.
    /// For example, a packet that sends vendor class with value of "FOO"
    /// will cause the packet to be assigned to class VENDOR_CLASS_FOO.
    static const std::string VENDOR_CLASS_PREFIX;

517
518
519
private:
    /// @brief Process Client FQDN %Option sent by a client.
    ///
520
521
522
523
524
525
    /// This function is called by the @c Dhcpv4Srv::processClientName when
    /// the client has sent the FQDN option in its message to the server.
    /// It comprises the actual logic to parse the FQDN option and prepare
    /// the FQDN option to be sent back to the client in the server's
    /// response.
    ///
526
527
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
528
    void processClientFqdnOption(Dhcpv4Exchange& ex);
529
530
531

    /// @brief Process Hostname %Option sent by a client.
    ///
Francis Dupont's avatar
Francis Dupont committed
532
    /// This function is called by the @c Dhcpv4Srv::processClientName when
533
534
535
536
537
    /// the client has sent the Hostname option in its message to the server.
    /// It comprises the actual logic to parse the Hostname option and
    /// prepare the Hostname option to be sent back to the client in the
    /// server's response.
    ///
538
539
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
540
    void processHostnameOption(Dhcpv4Exchange& ex);
541

542
543
544
545
546
547
548
    /// @brief Marks lease as declined.
    ///
    /// This method moves a lease to declined state with all the steps involved:
    /// - trigger DNS removal (if necessary)
    /// - disassociate the client information
    /// - update lease in the database (switch to DECLINED state)
    /// - increase necessary statistics
549
    /// - call lease4_decline hook
550
551
    ///
    /// @param lease lease to be declined
552
    /// @param decline client's message
553
    void
554
    declineLease(const Lease4Ptr& lease, const Pkt4Ptr& decline);
555

556
protected:
557
558
559
560

    /// @brief Creates NameChangeRequests which correspond to the lease
    /// which has been acquired.
    ///
Francis Dupont's avatar
Francis Dupont committed
561
    /// If this function is called when an existing lease is renewed, it
562
563
564
565
566
567
568
569
570
571
572
573
574
    /// may generate NameChangeRequest to remove existing DNS entries which
    /// correspond to the old lease instance. This function may cease to
    /// generate NameChangeRequests if the notion of the client's FQDN hasn't
    /// changed between an old and new lease.
    ///
    /// @param lease A pointer to the new lease which has been acquired.
    /// @param old_lease A pointer to the instance of the old lease which has
    /// been replaced by the new lease passed in the first argument. The NULL
    /// value indicates that the new lease has been allocated, rather than
    /// lease being renewed.
    void createNameChangeRequests(const Lease4Ptr& lease,
                                  const Lease4Ptr& old_lease);

575
576
    /// @brief Creates the NameChangeRequest and adds to the queue for
    /// processing.
577
    ///
578
579
580
    /// This creates the @c isc::dhcp_ddns::NameChangeRequest; emits a
    /// the debug message which indicates whether the request being added is
    /// to remove DNS entry or add a new entry; and then sends the request
581
    /// to the D2ClientMgr for transmission to kea-dhcp-ddns.
582
    ///
583
    /// @param chg_type A type of the NameChangeRequest (ADD or REMOVE).
584
585
    /// @param lease A lease for which the NameChangeRequest is created and
    /// queued.
586
587
    void queueNameChangeRequest(const isc::dhcp_ddns::NameChangeType chg_type,
                                const Lease4Ptr& lease);
588

589
590
591
592
593
    /// @brief Attempts to renew received addresses
    ///
    /// Attempts to renew existing lease. This typically includes finding a lease that
    /// corresponds to the received address. If no such lease is found, a status code
    /// response is generated.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
594
    ///
595
596
597
    /// @param renew client's message asking for renew
    /// @param reply server's response (ACK or NAK)
    void renewLease(const Pkt4Ptr& renew, Pkt4Ptr& reply);
Tomek Mrugalski's avatar
Tomek Mrugalski committed
598

599
600
    /// @brief Adds server identifier option to the server's response.
    ///
Francis Dupont's avatar
Francis Dupont committed
601
    /// This method adds a server identifier to the DHCPv4 message. It expects
602
603
604
605
606
607
608
609
610
611
612
    /// that the local (source) address is set for this message. If address is
    /// not set, it will throw an exception. This method also expects that the
    /// server identifier option is not present in the specified message.
    /// Otherwise, it will throw an exception on attempt to add a duplicate
    /// server identifier option.
    ///
    /// @note This method doesn't throw exceptions by itself but the underlying
    /// classes being used my throw. The reason for this method to not sanity
    /// check the specified message is that it is meant to be called internally
    /// by the @c Dhcpv4Srv class.
    ///
613
614
615
    /// @note This method is static because it is not dependent on the class
    /// state.
    ///
616
617
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
618
    static void appendServerID(Dhcpv4Exchange& ex);
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635

    /// @brief Set IP/UDP and interface parameters for the DHCPv4 response.
    ///
    /// This method sets the following parameters for the DHCPv4 message being
    /// sent to a client:
    /// - client unicast or a broadcast address,
    /// - client or relay port,
    /// - server address,
    /// - server port,
    /// - name and index of the interface which is to be used to send the
    /// message.
    ///
    /// Internally it calls the @c Dhcpv4Srv::adjustRemoteAddr to figure
    /// out the destination address (client unicast address or broadcast
    /// address).
    ///
    /// The destination port is always DHCPv4 client (68) or relay (67) port,
636
    /// depending if the response will be sent directly to a client.
637
638
639
640
641
642
643
644
645
646
    ///
    /// The source port is always set to DHCPv4 server port (67).
    ///
    /// The interface selected for the response is always the same as the
    /// one through which the query has been received.
    ///
    /// The source address for the response is the IPv4 address assigned to
    /// the interface being used to send the response. This function uses
    /// @c IfaceMgr to get the socket bound to the IPv4 address on the
    /// particular interface.
647
648
649
    ///
    /// @note This method is static because it is not dependent on the class
    /// state.
650
651
652
    ///
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
653
    static void adjustIfaceData(Dhcpv4Exchange& ex);
654

655
656
657
658
659
660
661
662
663
664
665
666
667
    /// @brief Sets remote addresses for outgoing packet.
    ///
    /// This method sets the local and remote addresses on outgoing packet.
    /// The addresses being set depend on the following conditions:
    /// - has incoming packet been relayed,
    /// - is direct response to a client without address supported,
    /// - type of the outgoing packet,
    /// - broadcast flag set in the incoming packet.
    ///
    /// @warning This method does not check whether provided packet pointers
    /// are valid. Make sure that pointers are correct before calling this
    /// function.
    ///
668
669
670
    /// @note This method is static because it is not dependent on the class
    /// state.
    ///
671
672
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
673
    static void adjustRemoteAddr(Dhcpv4Exchange& ex);
674

675
676
677
678
679
680
681
    /// @brief converts server-id to text
    /// Converts content of server-id option to a text representation, e.g.
    /// "192.0.2.1"
    ///
    /// @param opt option that contains server-id
    /// @return string representation
    static std::string srvidToString(const OptionPtr& opt);
682

683
    /// @brief Computes DHCID from a lease.
684
    ///
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
    /// This method creates an object which represents DHCID. The DHCID value
    /// is computed as described in RFC4701. The section 3.3. of RFC4701
    /// specifies the DHCID RR Identifier Type codes:
    /// - 0x0000 The 1 octet htype followed by glen octets of chaddr
    /// - 0x0001 The data octets from the DHCPv4 client's Client Identifier
    /// option.
    /// - 0x0002 The client's DUID.
    ///
    /// Currently this function supports first two of these identifiers.
    /// The 0x0001 is preferred over the 0x0000 - if the client identifier
    /// option is present, the former is used. If the client identifier
    /// is absent, the latter is used.
    ///
    /// @todo Implement support for 0x0002 DHCID identifier type.
    ///
700
    /// @param lease A pointer to the structure describing a lease.
701
    /// @return An object encapsulating DHCID to be used for DNS updates.
702
    /// @throw DhcidComputeError If the computation of the DHCID failed.
703
    static isc::dhcp_ddns::D2Dhcid computeDhcid(const Lease4Ptr& lease);
704

705
706
    /// @brief Selects a subnet for a given client's packet.
    ///
707
    /// @param query client's message
708
    /// @return selected subnet (or NULL if no suitable subnet was found)
709
    isc::dhcp::Subnet4Ptr selectSubnet(const Pkt4Ptr& query) const;
710

711
712
    /// indicates if shutdown is in progress. Setting it to true will
    /// initiate server shutdown procedure.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
713
    volatile bool shutdown_;
714

715
716
717
718
719
720
721
722
723
724
725
726
    /// @brief dummy wrapper around IfaceMgr::receive4
    ///
    /// This method is useful for testing purposes, where its replacement
    /// simulates reception of a packet. For that purpose it is protected.
    virtual Pkt4Ptr receivePacket(int timeout);

    /// @brief dummy wrapper around IfaceMgr::send()
    ///
    /// This method is useful for testing purposes, where its replacement
    /// simulates transmission of a packet. For that purpose it is protected.
    virtual void sendPacket(const Pkt4Ptr& pkt);

727
728
729
730
731
732
733
734
735
736
737
738
    /// @brief Implements a callback function to parse options in the message.
    ///
    /// @param buf a A buffer holding options in on-wire format.
    /// @param option_space A name of the option space which holds definitions
    /// of to be used to parse options in the packets.
    /// @param [out] options A reference to the collection where parsed options
    /// will be stored.
    /// @return An offset to the first byte after last parsed option.
    size_t unpackOptions(const OptionBuffer& buf,
                         const std::string& option_space,
                         isc::dhcp::OptionCollection& options);

739
740
741
742
743
744
745
    /// @brief Assigns incoming packet to zero or more classes.
    ///
    /// @note For now, the client classification is very simple. It just uses
    /// content of the vendor-class-identifier option as a class. The resulting
    /// class will be stored in packet (see @ref isc::dhcp::Pkt4::classes_ and
    /// @ref isc::dhcp::Pkt4::inClass).
    ///
746
747
748
749
750
    /// @param pkt packet to be classified
    void classifyPacket(const Pkt4Ptr& pkt);

    /// @brief Performs packet processing specific to a class
    ///
751
752
    /// If the selected subnet, query or response in the @c ex object is NULL
    /// this method returns immediately and returns true.
753
    ///
754
755
756
757
    /// @note This processing is a likely candidate to be pushed into hooks.
    ///
    /// @param ex The exchange holding both the client's message and the
    /// server's response.
758
    /// @return true if successful, false otherwise (will prevent sending response)
759
    bool classSpecificProcessing(const Dhcpv4Exchange& ex);
760

761
762
763
764
765
    /// @brief Allocation Engine.
    /// Pointer to the allocation engine that we are currently using
    /// It must be a pointer, because we will support changing engines
    /// during normal operation (e.g. to use different allocators)
    boost::shared_ptr<AllocEngine> alloc_engine_;
766

767
private:
768
769

    /// @brief Constructs netmask option based on subnet4
770
    /// @param subnet subnet for which the netmask will be calculated
771
772
773
774
    ///
    /// @return Option that contains netmask information
    static OptionPtr getNetmaskOption(const Subnet4Ptr& subnet);

775
776
777
778
779
780
781
    /// @brief Updates statistics for received packets
    /// @param query packet received
    static void processStatsReceived(const Pkt4Ptr& query);

    /// @brief Updates statistics for transmitted packets
    /// @param query packet transmitted
    static void processStatsSent(const Pkt4Ptr& response);
782

783
784
785
    uint16_t port_;  ///< UDP port number on which server listens.
    bool use_bcast_; ///< Should broadcast be enabled on sockets (if true).

786
787
788
789
    /// Indexes for registered hook points
    int hook_index_pkt4_receive_;
    int hook_index_subnet4_select_;
    int hook_index_pkt4_send_;
790
791
792
793
794
795
};

}; // namespace isc::dhcp
}; // namespace isc

#endif // DHCP4_SRV_H