dhcp4_srv.cc 100 KB
Newer Older
Francis Dupont's avatar
Francis Dupont committed
1
// Copyright (C) 2011-2016 Internet Systems Consortium, Inc. ("ISC")
2
//
3 4 5
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
6

7
#include <config.h>
8
#include <asiolink/io_address.h>
9
#include <dhcp/dhcp4.h>
10 11
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
12
#include <dhcp/iface_mgr.h>
13
#include <dhcp/option4_addrlst.h>
14
#include <dhcp/option_int.h>
15
#include <dhcp/option_int_array.h>
16
#include <dhcp/option_vendor.h>
17
#include <dhcp/option_string.h>
18
#include <dhcp/pkt4.h>
19
#include <dhcp/docsis3_option_defs.h>
20 21
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
22 23
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
24
#include <dhcpsrv/cfgmgr.h>
25
#include <dhcpsrv/cfg_subnets4.h>
26 27
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
28
#include <dhcpsrv/ncr_generator.h>
29
#include <dhcpsrv/subnet.h>
30
#include <dhcpsrv/subnet_selector.h>
31
#include <dhcpsrv/utils.h>
32
#include <dhcpsrv/utils.h>
33 34
#include <eval/evaluate.h>
#include <eval/eval_messages.h>
35
#include <hooks/callout_handle.h>
36
#include <hooks/hooks_log.h>
37
#include <hooks/hooks_manager.h>
38
#include <stats/stats_mgr.h>
39
#include <util/strutil.h>
40
#include <stats/stats_mgr.h>
41 42
#include <log/logger.h>
#include <cryptolink/cryptolink.h>
43
#include <cfgrpt/config_report.h>
44

45 46 47 48 49 50 51 52
#ifdef HAVE_MYSQL
#include <dhcpsrv/mysql_lease_mgr.h>
#endif
#ifdef HAVE_PGSQL
#include <dhcpsrv/pgsql_lease_mgr.h>
#endif
#include <dhcpsrv/memfile_lease_mgr.h>

53
#include <boost/asio.hpp>
54
#include <boost/bind.hpp>
55
#include <boost/foreach.hpp>
56
#include <boost/shared_ptr.hpp>
57 58 59

#include <iomanip>

60 61
using namespace isc;
using namespace isc::asiolink;
62
using namespace isc::cryptolink;
63
using namespace isc::dhcp;
64
using namespace isc::dhcp_ddns;
65
using namespace isc::hooks;
66
using namespace isc::log;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
67
using namespace isc::stats;
68
using namespace std;
69

70
/// Structure that holds registered hook indexes
71 72
struct Dhcp4Hooks {
    int hook_index_buffer4_receive_;///< index for "buffer4_receive" hook point
73 74
    int hook_index_pkt4_receive_;   ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_; ///< index for "subnet4_select" hook point
75
    int hook_index_lease4_release_; ///< index for "lease4_release" hook point
76
    int hook_index_pkt4_send_;      ///< index for "pkt4_send" hook point
77
    int hook_index_buffer4_send_;   ///< index for "buffer4_send" hook point
78
    int hook_index_lease4_decline_; ///< index for "lease4_decline" hook point
79

80 81 82
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
        hook_index_buffer4_receive_= HooksManager::registerHook("buffer4_receive");
83 84 85
        hook_index_pkt4_receive_   = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_ = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_      = HooksManager::registerHook("pkt4_send");
86 87
        hook_index_lease4_release_ = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_   = HooksManager::registerHook("buffer4_send");
88
        hook_index_lease4_decline_ = HooksManager::registerHook("lease4_decline");
89 90 91 92 93 94 95
    }
};

// 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.
96
Dhcp4Hooks Hooks;
97

98 99 100
namespace isc {
namespace dhcp {

101
Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
102 103
                               const Pkt4Ptr& query,
                               const Subnet4Ptr& subnet)
104 105
    : alloc_engine_(alloc_engine), query_(query), resp_(),
      context_(new AllocEngine::ClientContext4()) {
106

107 108 109 110 111 112 113 114
    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");
115 116
    }

117 118 119
    // Create response message.
    initResponse();
    // Select subnet for the query message.
120
    context_->subnet_ = subnet;
121
    // Hardware address.
122
    context_->hwaddr_ = query->getHWAddr();
123 124
    // Pointer to client's query.
    context_->query_ = query;
125

126
    // Set client identifier if the match-client-id flag is enabled (default).
127 128 129
    // If the subnet wasn't found it doesn't matter because we will not be
    // able to allocate a lease anyway so this context will not be used.
    if (subnet) {
130
        if (subnet->getMatchClientId()) {
131 132 133 134 135 136 137 138 139 140
            OptionPtr opt_clientid = query->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
            if (opt_clientid) {
                context_->clientid_.reset(new ClientId(opt_clientid->getData()));
            }
        } else {
            /// @todo When merging with #3806 use different logger.
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENTID_IGNORED_FOR_LEASES)
                .arg(query->getLabel())
                .arg(subnet->getID());
        }
141 142
    }
    // Check for static reservations.
143
    alloc_engine->findReservation(*context_);
144 145
};

146
void
147
Dhcpv4Exchange::initResponse() {
148 149 150 151 152 153 154 155 156 157 158 159
    uint8_t resp_type = 0;
    switch (getQuery()->getType()) {
    case DHCPDISCOVER:
        resp_type = DHCPOFFER;
        break;
    case DHCPREQUEST:
    case DHCPINFORM:
        resp_type = DHCPACK;
        break;
    default:
        ;
    }
160
    // Only create a response if one is required.
161 162
    if (resp_type > 0) {
        resp_.reset(new Pkt4(resp_type, getQuery()->getTransid()));
163
        copyDefaultFields();
Francis Dupont's avatar
Francis Dupont committed
164
        copyDefaultOptions();
165 166 167 168 169 170 171 172
    }
}

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

173 174
    // explicitly set this to 0
    resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS());
175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200
    // 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());

    // 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);
    }
201
}
202

203 204
void
Dhcpv4Exchange::copyDefaultOptions() {
205 206 207 208 209 210 211
    // 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);
    }
212 213 214 215 216

    // 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);
217
    }
218 219 220 221 222 223 224 225 226 227 228 229 230

    // RFC 3011 states about the Subnet Selection Option

    // "Servers configured to support this option MUST return an
    //  identical copy of the option to any client that sends it,
    //  regardless of whether or not the client requests the option in
    //  a parameter request list. Clients using this option MUST
    //  discard DHCPOFFER or DHCPACK packets that do not contain this
    //  option."
    OptionPtr subnet_sel = query_->getOption(DHO_SUBNET_SELECTION);
    if (subnet_sel) {
        resp_->addOption(subnet_sel);
    }
231 232
}

233 234
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

235
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast,
236
                     const bool direct_response_desired)
237 238 239
    : 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) {
240

241
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
242
    try {
243 244 245
        // 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.
246
        if (port) {
247 248 249 250 251 252 253 254
            // 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);
255
        }
256

257 258 259 260
        // Instantiate allocation engine. The number of allocation attempts equal
        // to zero indicates that the allocation engine will use the number of
        // attempts depending on the pool size.
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 0,
261
                                            false /* false = IPv4 */));
262

263 264 265 266 267 268 269
        // 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

270
    } catch (const std::exception &e) {
271
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
272 273 274
        shutdown_ = true;
        return;
    }
275

Tomek Mrugalski's avatar
Tomek Mrugalski committed
276
    shutdown_ = false;
277 278 279
}

Dhcpv4Srv::~Dhcpv4Srv() {
280 281 282 283 284 285
    try {
        stopD2();
    } catch(const std::exception& ex) {
        // Highly unlikely, but lets Report it but go on
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_D2STOP_ERROR).arg(ex.what());
    }
286

Tomek Mrugalski's avatar
Tomek Mrugalski committed
287
    IfaceMgr::instance().closeSockets();
Tomek Mrugalski's avatar
Tomek Mrugalski committed
288

289 290
    // The lease manager was instantiated during DHCPv4Srv configuration,
    // so we should clean up after ourselves.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
291
    LeaseMgrFactory::destroy();
292 293
}

294 295
void
Dhcpv4Srv::shutdown() {
296
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
297 298 299
    shutdown_ = true;
}

300
isc::dhcp::Subnet4Ptr
301
Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
302 303 304 305 306 307 308 309 310 311 312

    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();

313 314 315 316 317 318
    // If the link-selection sub-option is present, extract its value.
    // "The link-selection sub-option is used by any DHCP relay agent
    // that desires to specify a subnet/link for a DHCP client request
    // that it is relaying but needs the subnet/link specification to
    // be different from the IP address the DHCP server should use
    // when communicating with the relay agent." (RFC 3257)
319
    //
320
    // Try first Relay Agent Link Selection sub-option
321 322
    OptionPtr rai = query->getOption(DHO_DHCP_AGENT_OPTIONS);
    if (rai) {
323 324 325 326 327 328 329 330
        OptionCustomPtr rai_custom =
            boost::dynamic_pointer_cast<OptionCustom>(rai);
        if (rai_custom) {
            OptionPtr link_select =
                rai_custom->getOption(RAI_OPTION_LINK_SELECTION);
            if (link_select) {
                OptionBuffer link_select_buf = link_select->getData();
                if (link_select_buf.size() == sizeof(uint32_t)) {
331
                    selector.option_select_ =
332
                        IOAddress::fromBytes(AF_INET, &link_select_buf[0]);
333 334 335
                }
            }
        }
336 337 338 339 340 341 342 343 344 345
    } else {
        // Or Subnet Selection option
        OptionPtr sbnsel = query->getOption(DHO_SUBNET_SELECTION);
        if (sbnsel) {
            OptionCustomPtr oc =
                boost::dynamic_pointer_cast<OptionCustom>(sbnsel);
            if (oc) {
                selector.option_select_ = oc->readAddress();
            }
        }
346 347
    }

348 349 350 351
    CfgMgr& cfgmgr = CfgMgr::instance();
    subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet(selector);

    // Let's execute all callouts registered for subnet4_select
352
    if (HooksManager::calloutsPresent(hook_index_subnet4_select_)) {
353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371
        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)
372
        if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
373
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
374 375
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
376 377 378
            return (Subnet4Ptr());
        }

379 380
        /// @todo: Add support for DROP status

381 382 383 384
        // Use whatever subnet was specified by the callout
        callout_handle->getArgument("subnet4", subnet);
    }

385 386
    if (subnet) {
        // Log at higher debug level that subnet has been found.
387
        LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
388 389 390 391
            .arg(query->getLabel())
            .arg(subnet->getID());
        // Log detailed information about the selected subnet at the
        // lower debug level.
392
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_DATA)
393 394 395 396
            .arg(query->getLabel())
            .arg(subnet->toText());

    } else {
397
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL,
398 399 400 401
                  DHCP4_SUBNET_SELECTION_FAILED)
            .arg(query->getLabel());
    }

402
    return (subnet);
403 404
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
405 406
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
407 408 409
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
410 411
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
412 413 414
    IfaceMgr::instance().send(packet);
}

415 416
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
417
    while (!shutdown_) {
418
        try {
Francis Dupont's avatar
Francis Dupont committed
419
            run_one();
420
        } catch (const std::exception& e) {
Francis Dupont's avatar
Francis Dupont committed
421 422 423
            // General catch-all exception that are not caught by more specific
            // catches. This one is for exceptions derived from std::exception.
            LOG_ERROR(packet4_logger, DHCP4_PACKET_PROCESS_EXCEPTION)
424
                .arg(e.what());
Francis Dupont's avatar
Francis Dupont committed
425 426 427 428 429 430
        } catch (...) {
            // General catch-all exception that are not caught by more specific
            // catches. This one is for other exceptions, not derived from
            // std::exception.
            LOG_ERROR(packet4_logger, DHCP4_PACKET_PROCESS_EXCEPTION)
                .arg("an unknown exception not derived from std::exception");
431
        }
Francis Dupont's avatar
Francis Dupont committed
432
    }
433

Francis Dupont's avatar
Francis Dupont committed
434 435
    return (true);
}
436

Francis Dupont's avatar
Francis Dupont committed
437 438 439 440 441
void
Dhcpv4Srv::run_one() {
    // client's message and server's response
    Pkt4Ptr query;
    Pkt4Ptr rsp;
442

Francis Dupont's avatar
Francis Dupont committed
443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460
    try {
        uint32_t timeout = 1000;
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT).arg(timeout);
        query = receivePacket(timeout);

        // 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) {
            LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC, DHCP4_BUFFER_RECEIVED)
                .arg(query->getRemoteAddr().toText())
                .arg(query->getRemotePort())
                .arg(query->getLocalAddr().toText())
                .arg(query->getLocalPort())
                .arg(query->getIface());
461

Francis Dupont's avatar
Francis Dupont committed
462 463 464 465
        } else {
            LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_INTERRUPTED)
                .arg(timeout);
        }
466

Francis Dupont's avatar
Francis Dupont committed
467 468 469 470 471 472 473 474 475 476 477 478
    } 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, SIGHUP or SIGCHILD which are handled by the server. For
        // signals that are not handled by the server we rely on the default
        // behavior of the system.
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_SIGNAL)
            .arg(signal_set_->getNext());
    } catch (const std::exception& e) {
        // Log all other errors.
        LOG_ERROR(packet4_logger, DHCP4_BUFFER_RECEIVE_FAIL).arg(e.what());
    }
479

Francis Dupont's avatar
Francis Dupont committed
480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497
    // 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
    // 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.
    try {
        handleSignal();
    } catch (const std::exception& e) {
        // Standard exception occurred. Let's be on the safe side to
        // catch std::exception.
        LOG_ERROR(dhcp4_logger, DHCP4_HANDLE_SIGNAL_EXCEPTION)
            .arg(e.what());
    }
498

Francis Dupont's avatar
Francis Dupont committed
499 500 501 502 503 504
    // Timeout may be reached or signal received, which breaks select()
    // with no reception occurred. No need to log anything here because
    // we have logged right after the call to receivePacket().
    if (!query) {
        return;
    }
505

Francis Dupont's avatar
Francis Dupont committed
506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527
    // 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",
                                              static_cast<int64_t>(1));

    // 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));

    bool skip_unpack = false;

    // The packet has just been received so contains the uninterpreted wire
    // data; execute callouts registered for buffer4_receive.
    if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_receive_)) {
        CalloutHandlePtr callout_handle = getCalloutHandle(query);
528

Francis Dupont's avatar
Francis Dupont committed
529 530
        // Delete previously set arguments
        callout_handle->deleteAllArguments();
531

Francis Dupont's avatar
Francis Dupont committed
532 533
        // Pass incoming packet as argument
        callout_handle->setArgument("query4", query);
534

Francis Dupont's avatar
Francis Dupont committed
535 536 537
        // Call callouts
        HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                   *callout_handle);
538

Francis Dupont's avatar
Francis Dupont committed
539 540 541 542 543 544 545 546 547 548
        // 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->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
            LOG_DEBUG(hooks_logger, DBG_DHCP4_DETAIL, DHCP4_HOOK_BUFFER_RCVD_SKIP)
                .arg(query->getRemoteAddr().toText())
                .arg(query->getLocalAddr().toText())
                .arg(query->getIface());
            skip_unpack = true;
549
        }
550

Francis Dupont's avatar
Francis Dupont committed
551
        callout_handle->getArgument("query4", query);
552

Francis Dupont's avatar
Francis Dupont committed
553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572
        /// @todo: add support for DROP status
    }

    // Unpack the packet information unless the buffer4_receive callouts
    // indicated they did it
    if (!skip_unpack) {
        try {
            LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_UNPACK)
                .arg(query->getRemoteAddr().toText())
                .arg(query->getLocalAddr().toText())
                .arg(query->getIface());
            query->unpack();
        } catch (const std::exception& e) {
            // Failed to parse the packet.
            LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL,
                      DHCP4_PACKET_DROP_0001)
                .arg(query->getRemoteAddr().toText())
                .arg(query->getLocalAddr().toText())
                .arg(query->getIface())
                .arg(e.what());
573

Francis Dupont's avatar
Francis Dupont committed
574 575 576
            // Increase the statistics of parse failues and dropped packets.
            isc::stats::StatsMgr::instance().addValue("pkt4-parse-failed",
                                                      static_cast<int64_t>(1));
Tomek Mrugalski's avatar
Tomek Mrugalski committed
577
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
578
                                                      static_cast<int64_t>(1));
Francis Dupont's avatar
Francis Dupont committed
579
            return;
580
        }
Francis Dupont's avatar
Francis Dupont committed
581
    }
582

Francis Dupont's avatar
Francis Dupont committed
583 584
    // Update statistics accordingly for received packet.
    processStatsReceived(query);
585

Francis Dupont's avatar
Francis Dupont committed
586 587 588 589
    // 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.
    classifyPacket(query);
590

Francis Dupont's avatar
Francis Dupont committed
591 592 593 594 595 596 597 598
    // 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)) {
        // Increase the statistic of dropped packets.
        isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
                                                  static_cast<int64_t>(1));
        return;
    }
599

Francis Dupont's avatar
Francis Dupont committed
600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616
    // We have sanity checked (in accept() that the Message Type option
    // exists, so we can safely get it here.
    int type = query->getType();
    LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC_DATA, DHCP4_PACKET_RECEIVED)
        .arg(query->getLabel())
        .arg(query->getName())
        .arg(type)
        .arg(query->getRemoteAddr())
        .arg(query->getLocalAddr())
        .arg(query->getIface());
    LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
        .arg(query->getLabel())
        .arg(query->toText());

    // Let's execute all callouts registered for pkt4_receive
    if (HooksManager::calloutsPresent(hook_index_pkt4_receive_)) {
        CalloutHandlePtr callout_handle = getCalloutHandle(query);
617

Francis Dupont's avatar
Francis Dupont committed
618 619
        // Delete previously set arguments
        callout_handle->deleteAllArguments();
620

Francis Dupont's avatar
Francis Dupont committed
621 622
        // Pass incoming packet as argument
        callout_handle->setArgument("query4", query);
623

Francis Dupont's avatar
Francis Dupont committed
624 625 626
        // Call callouts
        HooksManager::callCallouts(hook_index_pkt4_receive_,
                                   *callout_handle);
627

Francis Dupont's avatar
Francis Dupont committed
628 629 630 631 632 633 634
        // 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->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP)
                .arg(query->getLabel());
            return;
635
        }
636

Francis Dupont's avatar
Francis Dupont committed
637
        /// @todo: Add support for DROP status
638

Francis Dupont's avatar
Francis Dupont committed
639 640
        callout_handle->getArgument("query4", query);
    }
641

Francis Dupont's avatar
Francis Dupont committed
642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671
    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:
            rsp = 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.
            ;
672
        }
Francis Dupont's avatar
Francis Dupont committed
673 674 675 676 677 678 679 680 681 682 683 684 685
    } catch (const std::exception& e) {

        // Catch-all exception (we used to call only isc::Exception, but
        // std::exception could potentially be raised and if we don't catch
        // it here, it would be caught in main() and the process would
        // terminate).  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.)
        LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_BASIC,
                  DHCP4_PACKET_DROP_0007)
            .arg(query->getLabel())
            .arg(e.what());
686

Francis Dupont's avatar
Francis Dupont committed
687 688 689 690
        // Increase the statistic of dropped packets.
        isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
                                                  static_cast<int64_t>(1));
    }
691

Francis Dupont's avatar
Francis Dupont committed
692 693 694
    if (!rsp) {
        return;
    }
695

696

Francis Dupont's avatar
Francis Dupont committed
697 698
    // Specifies if server should do the packing
    bool skip_pack = false;
699

Francis Dupont's avatar
Francis Dupont committed
700 701 702
    // Execute all callouts registered for pkt4_send
    if (HooksManager::calloutsPresent(hook_index_pkt4_send_)) {
        CalloutHandlePtr callout_handle = getCalloutHandle(query);
703

Francis Dupont's avatar
Francis Dupont committed
704 705
        // Delete all previous arguments
        callout_handle->deleteAllArguments();
706

Francis Dupont's avatar
Francis Dupont committed
707 708
        // Clear skip flag if it was set in previous callouts
        callout_handle->setStatus(CalloutHandle::NEXT_STEP_CONTINUE);
709

Francis Dupont's avatar
Francis Dupont committed
710 711
        // Set our response
        callout_handle->setArgument("response4", rsp);
712

Francis Dupont's avatar
Francis Dupont committed
713 714
        // Also pass the corresponding query packet as argument
        callout_handle->setArgument("query4", query);
715

Francis Dupont's avatar
Francis Dupont committed
716 717 718
        // Call all installed callouts
        HooksManager::callCallouts(hook_index_pkt4_send_,
                                   *callout_handle);
719

Francis Dupont's avatar
Francis Dupont committed
720 721 722 723 724 725 726
        // 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->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_SEND_SKIP)
                .arg(query->getLabel());
            skip_pack = true;
727 728
        }

Francis Dupont's avatar
Francis Dupont committed
729 730
        /// @todo: Add support for DROP status
    }
731

Francis Dupont's avatar
Francis Dupont committed
732
    if (!skip_pack) {
733
        try {
Francis Dupont's avatar
Francis Dupont committed
734 735 736 737 738 739 740 741 742
            LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_PACK)
                .arg(rsp->getLabel());
            rsp->pack();
        } catch (const std::exception& e) {
            LOG_ERROR(options4_logger, DHCP4_PACKET_PACK_FAIL)
                .arg(rsp->getLabel())
                .arg(e.what());
        }
    }
743

Francis Dupont's avatar
Francis Dupont committed
744 745 746 747 748 749 750
    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.
        // Let's execute all callouts registered for buffer4_send
        if (HooksManager::calloutsPresent(Hooks.hook_index_buffer4_send_)) {
            CalloutHandlePtr callout_handle = getCalloutHandle(query);
751

Francis Dupont's avatar
Francis Dupont committed
752 753
            // Delete previously set arguments
            callout_handle->deleteAllArguments();
754

Francis Dupont's avatar
Francis Dupont committed
755 756
            // Pass incoming packet as argument
            callout_handle->setArgument("response4", rsp);
757

Francis Dupont's avatar
Francis Dupont committed
758 759 760
            // Call callouts
            HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
                                       *callout_handle);
761

Francis Dupont's avatar
Francis Dupont committed
762 763 764 765 766 767 768 769 770
            // 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->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
                          DHCP4_HOOK_BUFFER_SEND_SKIP)
                    .arg(rsp->getLabel());
                return;
            }
771

Francis Dupont's avatar
Francis Dupont committed
772 773 774
            /// @todo: Add support for DROP status.

            callout_handle->getArgument("response4", rsp);
775
        }
776

Francis Dupont's avatar
Francis Dupont committed
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
        LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND)
            .arg(rsp->getLabel())
            .arg(rsp->getName())
            .arg(static_cast<int>(rsp->getType()))
            .arg(rsp->getLocalAddr())
            .arg(rsp->getLocalPort())
            .arg(rsp->getRemoteAddr())
            .arg(rsp->getRemotePort())
            .arg(rsp->getIface());

        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA,
                  DHCP4_RESPONSE_DATA)
            .arg(rsp->getLabel())
            .arg(rsp->getName())
            .arg(static_cast<int>(rsp->getType()))
            .arg(rsp->toText());
        sendPacket(rsp);

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

    } catch (const std::exception& e) {
        LOG_ERROR(packet4_logger, DHCP4_PACKET_SEND_FAIL)
            .arg(rsp->getLabel())
            .arg(e.what());
    }
803 804
}

805
string
806
Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822
    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());
823 824
}

825
void
826
Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) {
827 828 829
    // 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.
830 831
    /// @todo: perhaps we should consider some more sophisticated server id
    /// generation, but for the current use cases, it should be ok.
832 833 834
    OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                           ex.getResponse()->getLocalAddr()));
    ex.getResponse()->addOption(opt_srvid);
835 836
}

837 838 839 840 841 842
void
Dhcpv4Srv::buildCfgOptionList(Dhcpv4Exchange& ex) {
    CfgOptionList& co_list = ex.getCfgOptionList();

    // First subnet configured options
    Subnet4Ptr subnet = ex.getContext()->subnet_;
843 844 845 846 847 848
    if (!subnet) {
        // All methods using the CfgOptionList object return soon when
        // there is no subnet so do the same
        return;
    }
    if (!subnet->getCfgOption()->empty()) {
849 850 851 852 853 854 855 856 857 858 859 860
        co_list.push_back(subnet->getCfgOption());
    }

    // Each class in the incoming packet
    const ClientClasses& classes = ex.getQuery()->getClasses();
    for (ClientClasses::const_iterator cclass = classes.begin();
         cclass != classes.end(); ++cclass) {
        // Find the client class definition for this class
        const ClientClassDefPtr& ccdef = CfgMgr::instance().getCurrentCfg()->
            getClientClassDictionary()->findClass(*cclass);
        if (!ccdef) {
            // Not found: the class is not configured
861 862 863
            if (((*cclass).size() <= VENDOR_CLASS_PREFIX.size()) ||
                ((*cclass).compare(0, VENDOR_CLASS_PREFIX.size(), VENDOR_CLASS_PREFIX) != 0)) {
                // Not a VENDOR_CLASS_* so should be configured
864
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_UNCONFIGURED)
865 866 867 868
                    .arg(ex.getQuery()->getLabel())
                    .arg(*cclass);
            }
            // Skip it
869 870
            continue;
        }
871 872 873 874
        if (ccdef->getCfgOption()->empty()) {
            // Skip classes which don't configure options
            continue;
        }
875 876 877 878
        co_list.push_back(ccdef->getCfgOption());
    }

    // Last global options
879 880 881
    if (!CfgMgr::instance().getCurrentCfg()->getCfgOption()->empty()) {
        co_list.push_back(CfgMgr::instance().getCurrentCfg()->getCfgOption());
    }
882 883
}

884
void
885
Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) {
886 887
    // Get the subnet relevant for the client. We will need it
    // to get the options associated with it.
888
    Subnet4Ptr subnet = ex.getContext()->subnet_;
889 890 891 892 893 894 895
    // 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;
    }
896

897 898 899 900 901 902
    // Unlikely short cut
    const CfgOptionList& co_list = ex.getCfgOptionList();
    if (co_list.empty()) {
        return;
    }

903 904
    Pkt4Ptr query = ex.getQuery();

905 906 907
    // try to get the 'Parameter Request List' option which holds the
    // codes of requested options.
    OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast<
908
        OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST));
909 910 911 912 913
    // If there is no PRL option in the message from the client then
    // there is nothing to do.
    if (!option_prl) {
        return;
    }
914

915 916
    Pkt4Ptr resp = ex.getResponse();

917 918 919 920 921 922
    // 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) {
923
        // Add nothing when it is already there
924
        if (!resp->getOption(*opt)) {
925 926 927 928 929
            // Iterate on the configured option list
            for (CfgOptionList::const_iterator copts = co_list.begin();
                 copts != co_list.end(); ++copts) {
                OptionDescriptor desc = (*copts)->get("dhcp4", *opt);
                // Got it: add it and jump to the outer loop
930 931
                if (desc.option_) {
                    resp->addOption(desc.option_);
932
                    break;
933 934 935 936
                }
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
937
}
938

939
void
940
Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) {
941
    // Get the configured subnet suitable for the incoming packet.
942
    Subnet4Ptr subnet = ex.getContext()->subnet_;
943 944 945 946 947 948 949 950 951
    // 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;
    }

952 953 954 955 956 957
    // Unlikely short cut
    const CfgOptionList& co_list = ex.getCfgOptionList();
    if (co_list.empty()) {
        return;
    }

958
    // Try to get the vendor option
959 960
    boost::shared_ptr<OptionVendor> vendor_req = boost::dynamic_pointer_cast<
        OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS));
961 962 963 964 965 966 967
    if (!vendor_req) {
        return;
    }

    uint32_t vendor_id = vendor_req->getVendorId();

    // Let's try to get ORO within that vendor-option
968 969
    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
    /// vendors may have different policies.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
970 971
    OptionUint8ArrayPtr oro =
        boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
972 973 974 975 976 977 978 979 980 981

    // 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;
982
    const std::vector<uint8_t>& requested_opts = oro->getValues();
983

Tomek Mrugalski's avatar
Tomek Mrugalski committed
984
    for (std::vector<uint8_t>::const_iterator code = requested_opts.begin();
985
         code != requested_opts.end(); ++code) {
986
        if  (!vendor_rsp->getOption(*code)) {
987 988 989 990 991 992 993 994
            for (CfgOptionList::const_iterator copts = co_list.begin();
                 copts != co_list.end(); ++copts) {
                OptionDescriptor desc = (*copts)->get(vendor_id, *code);
                if (desc.option_) {
                    vendor_rsp->addOption(desc.option_);
                    added = true;
                    break;
                }
995
            }
996 997
        }

998
        if (added) {
999
            ex.getResponse()->addOption(vendor_rsp);
1000 1001
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
1002
}
1003

1004

1005
void
1006
Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) {
1007 1008 1009 1010 1011 1012
    // 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 };
1013

1014 1015 1016 1017
    static size_t required_options_size =
        sizeof(required_options) / sizeof(required_options[0]);

    // Get the subnet.
1018
    Subnet4Ptr subnet = ex.getContext()->subnet_;
1019 1020 1021 1022
    if (!subnet) {
        return;
    }

1023 1024 1025 1026 1027 1028
    // Unlikely short cut
    const CfgOptionList& co_list = ex.getCfgOptionList();
    if (co_list.empty()) {
        return;
    }

1029 1030
    Pkt4Ptr resp = ex.getResponse();

1031 1032 1033
    // 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) {
1034
        OptionPtr opt = resp->getOption(required_options[i]);
1035 1036
        if (!opt) {
            // Check whether option has been configured.
1037 1038 1039 1040 1041 1042 1043
            for (CfgOptionList::const_iterator copts = co_list.begin();
                 copts != co_list.end(); ++copts) {
                OptionDescriptor desc = (*copts)->get("dhcp4", required_options[i]);
                if (desc.option_) {
                    resp->addOption(desc.option_);
                    break;
                }
1044 1045 1046
            }
        }
    }
Tomek Mrugalski's avatar
Tomek Mrugalski committed
1047
}
1048

1049
void
1050
Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) {
1051 1052 1053
    // 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.