dhcp4_srv.cc 116 KB
Newer Older
Francis Dupont's avatar
Francis Dupont committed
1
// Copyright (C) 2011-2017 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 <dhcp/dhcp4.h>
9 10
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
11
#include <dhcp/iface_mgr.h>
12
#include <dhcp/option4_addrlst.h>
13
#include <dhcp/option_int.h>
14
#include <dhcp/option_int_array.h>
15
#include <dhcp/option_vendor.h>
16
#include <dhcp/option_string.h>
17
#include <dhcp/pkt4.h>
18 19
#include <dhcp/pkt4o6.h>
#include <dhcp/pkt6.h>
20
#include <dhcp/docsis3_option_defs.h>
21
#include <dhcp4/dhcp4to6_ipc.h>
22 23
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
24 25
#include <dhcpsrv/addr_utilities.h>
#include <dhcpsrv/callout_handle_store.h>
26
#include <dhcpsrv/cfgmgr.h>
27
#include <dhcpsrv/cfg_host_operations.h>
28
#include <dhcpsrv/cfg_subnets4.h>
29 30
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
31
#include <dhcpsrv/ncr_generator.h>
32
#include <dhcpsrv/shared_network.h>
33
#include <dhcpsrv/subnet.h>
34
#include <dhcpsrv/subnet_selector.h>
35
#include <dhcpsrv/utils.h>
36
#include <dhcpsrv/utils.h>
37 38
#include <eval/evaluate.h>
#include <eval/eval_messages.h>
39
#include <hooks/callout_handle.h>
40
#include <hooks/hooks_log.h>
41
#include <hooks/hooks_manager.h>
42
#include <stats/stats_mgr.h>
43
#include <util/strutil.h>
44
#include <stats/stats_mgr.h>
45 46
#include <log/logger.h>
#include <cryptolink/cryptolink.h>
47
#include <cfgrpt/config_report.h>
48

49 50 51 52 53 54
#ifdef HAVE_MYSQL
#include <dhcpsrv/mysql_lease_mgr.h>
#endif
#ifdef HAVE_PGSQL
#include <dhcpsrv/pgsql_lease_mgr.h>
#endif
Tomek Mrugalski's avatar
Tomek Mrugalski committed
55 56
#ifdef HAVE_CQL
#include <dhcpsrv/cql_lease_mgr.h>
57
#endif
58 59
#include <dhcpsrv/memfile_lease_mgr.h>

60
#include <boost/algorithm/string/join.hpp>
61
#include <boost/bind.hpp>
62
#include <boost/foreach.hpp>
63
#include <boost/shared_ptr.hpp>
64 65 66

#include <iomanip>

67 68
using namespace isc;
using namespace isc::asiolink;
69
using namespace isc::cryptolink;
70
using namespace isc::dhcp;
71
using namespace isc::dhcp_ddns;
72
using namespace isc::hooks;
73
using namespace isc::log;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
74
using namespace isc::stats;
75
using namespace std;
76

77
/// Structure that holds registered hook indexes
78
struct Dhcp4Hooks {
79 80 81 82 83 84 85 86
    int hook_index_buffer4_receive_; ///< index for "buffer4_receive" hook point
    int hook_index_pkt4_receive_;    ///< index for "pkt4_receive" hook point
    int hook_index_subnet4_select_;  ///< index for "subnet4_select" hook point
    int hook_index_lease4_release_;  ///< index for "lease4_release" hook point
    int hook_index_pkt4_send_;       ///< index for "pkt4_send" hook point
    int hook_index_buffer4_send_;    ///< index for "buffer4_send" hook point
    int hook_index_lease4_decline_;  ///< index for "lease4_decline" hook point
    int hook_index_host4_identifier_;///< index for "host4_identifier" hook point
87

88 89
    /// Constructor that registers hook points for DHCPv4 engine
    Dhcp4Hooks() {
90 91 92 93 94 95 96 97
        hook_index_buffer4_receive_  = HooksManager::registerHook("buffer4_receive");
        hook_index_pkt4_receive_     = HooksManager::registerHook("pkt4_receive");
        hook_index_subnet4_select_   = HooksManager::registerHook("subnet4_select");
        hook_index_pkt4_send_        = HooksManager::registerHook("pkt4_send");
        hook_index_lease4_release_   = HooksManager::registerHook("lease4_release");
        hook_index_buffer4_send_     = HooksManager::registerHook("buffer4_send");
        hook_index_lease4_decline_   = HooksManager::registerHook("lease4_decline");
        hook_index_host4_identifier_ = HooksManager::registerHook("host4_identifier");
98 99 100 101 102 103 104
    }
};

// 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.
105
Dhcp4Hooks Hooks;
106

107 108 109
namespace isc {
namespace dhcp {

110
Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
111 112
                               const Pkt4Ptr& query,
                               const Subnet4Ptr& subnet)
113 114
    : alloc_engine_(alloc_engine), query_(query), resp_(),
      context_(new AllocEngine::ClientContext4()) {
115

116 117 118 119 120 121 122 123
    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");
124 125
    }

126 127 128
    // Create response message.
    initResponse();
    // Select subnet for the query message.
129
    context_->subnet_ = subnet;
130
    // Hardware address.
131
    context_->hwaddr_ = query->getHWAddr();
132 133
    // Pointer to client's query.
    context_->query_ = query;
134

135
    // Set client identifier if the match-client-id flag is enabled (default).
136 137 138
    // 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) {
139
        if (subnet->getMatchClientId()) {
140 141 142 143 144 145 146 147 148 149
            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());
        }
150

151
        // Find static reservations if not disabled for our subnet.
152
        if (subnet->getHostReservationMode() != Network::HR_DISABLED) {
153 154 155
            // Before we can check for static reservations, we need to prepare a set
            // of identifiers to be used for this.
            setHostIdentifiers();
156

157 158
            // Check for static reservations.
            alloc_engine->findReservation(*context_);
159 160
        }
    }
161 162 163 164 165 166 167 168

    const ClientClasses& classes = query_->getClasses();
    if (!classes.empty()) {
        std::string joined_classes = boost::algorithm::join(classes, ", ");
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_ASSIGNED)
            .arg(query_->getLabel())
            .arg(joined_classes);
    }
169 170
};

171
void
172
Dhcpv4Exchange::initResponse() {
173 174 175 176 177 178 179 180 181 182 183 184
    uint8_t resp_type = 0;
    switch (getQuery()->getType()) {
    case DHCPDISCOVER:
        resp_type = DHCPOFFER;
        break;
    case DHCPREQUEST:
    case DHCPINFORM:
        resp_type = DHCPACK;
        break;
    default:
        ;
    }
185
    // Only create a response if one is required.
186 187
    if (resp_type > 0) {
        resp_.reset(new Pkt4(resp_type, getQuery()->getTransid()));
188
        copyDefaultFields();
Francis Dupont's avatar
Francis Dupont committed
189
        copyDefaultOptions();
190 191 192 193

        if (getQuery()->isDhcp4o6()) {
            initResponse4o6();
        }
194 195 196
    }
}

197 198 199 200 201
void
Dhcpv4Exchange::initResponse4o6() {
    Pkt4o6Ptr query = boost::dynamic_pointer_cast<Pkt4o6>(getQuery());
    if (!query) {
        return;
202
    }
203 204 205 206 207 208 209 210 211 212 213 214
    const Pkt6Ptr& query6 = query->getPkt6();
    Pkt6Ptr resp6(new Pkt6(DHCPV6_DHCPV4_RESPONSE, query6->getTransid()));
    // Don't add client-id or server-id
    // But copy relay info
    if (!query6->relay_info_.empty()) {
        resp6->copyRelayInfo(query6);
    }
    // Copy interface and remote address
    resp6->setIface(query6->getIface());
    resp6->setIndex(query6->getIndex());
    resp6->setRemoteAddr(query6->getRemoteAddr());
    resp_.reset(new Pkt4o6(resp_, resp6));
215 216 217 218 219 220 221
}

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

222 223
    // explicitly set this to 0
    resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS());
224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249
    // 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);
    }
250

251
    // Copy flags from the request to the response per RFC 2131
252
    resp_->setFlags(query_->getFlags());
253
}
254

255 256
void
Dhcpv4Exchange::copyDefaultOptions() {
257 258
    // Let's copy client-id to response. See RFC6842.
    // It is possible to disable RFC6842 to keep backward compatibility
259
    bool echo = CfgMgr::instance().getCurrentCfg()->getEchoClientId();
260 261 262 263
    OptionPtr client_id = query_->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (client_id && echo) {
        resp_->addOption(client_id);
    }
264 265 266 267 268

    // 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);
269
    }
270 271 272 273 274 275 276 277 278 279 280 281 282

    // 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);
    }
283 284
}

285 286 287 288
void
Dhcpv4Exchange::setHostIdentifiers() {
    const ConstCfgHostOperationsPtr cfg =
        CfgMgr::instance().getCurrentCfg()->getCfgHostOperations4();
289

290 291
    // Collect host identifiers. The identifiers are stored in order of preference.
    // The server will use them in that order to search for host reservations.
292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332
    BOOST_FOREACH(const Host::IdentifierType& id_type,
                  cfg->getIdentifierTypes()) {
        switch (id_type) {
        case Host::IDENT_HWADDR:
            if (context_->hwaddr_ && !context_->hwaddr_->hwaddr_.empty()) {
                context_->addHostIdentifier(id_type, context_->hwaddr_->hwaddr_);
            }
            break;

        case Host::IDENT_DUID:
            if (context_->clientid_) {
                const std::vector<uint8_t>& vec = context_->clientid_->getDuid();
                if (!vec.empty()) {
                    // Client identifier type = DUID? Client identifier holding a DUID
                    // comprises Type (1 byte), IAID (4 bytes), followed by the actual
                    // DUID. Thus, the minimal length is 6.
                    if ((vec[0] == CLIENT_ID_OPTION_TYPE_DUID) && (vec.size() > 5)) {
                        // Extract DUID, skip IAID.
                        context_->addHostIdentifier(id_type,
                                                    std::vector<uint8_t>(vec.begin() + 5,
                                                                         vec.end()));
                    }
                }
            }
            break;

        case Host::IDENT_CIRCUIT_ID:
            {
                OptionPtr rai = query_->getOption(DHO_DHCP_AGENT_OPTIONS);
                if (rai) {
                    OptionPtr circuit_id_opt = rai->getOption(RAI_OPTION_AGENT_CIRCUIT_ID);
                    if (circuit_id_opt) {
                        const OptionBuffer& circuit_id_vec = circuit_id_opt->getData();
                        if (!circuit_id_vec.empty()) {
                            context_->addHostIdentifier(id_type, circuit_id_vec);
                        }
                    }
                }
            }
            break;

333 334 335 336 337 338 339 340
        case Host::IDENT_CLIENT_ID:
            if (context_->clientid_) {
                const std::vector<uint8_t>& vec = context_->clientid_->getDuid();
                if (!vec.empty()) {
                    context_->addHostIdentifier(id_type, vec);
                }
            }
            break;
341
        case Host::IDENT_FLEX:
342 343 344 345 346
            {
                if (!HooksManager::calloutsPresent(Hooks.hook_index_host4_identifier_)) {
                    break;
                }

347
                CalloutHandlePtr callout_handle = getCalloutHandle(context_->query_);
348

349 350 351 352 353 354 355 356 357 358 359
                Host::IdentifierType type = Host::IDENT_FLEX;
                std::vector<uint8_t> id;

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

                // Pass incoming packet as argument
                callout_handle->setArgument("query4", context_->query_);
                callout_handle->setArgument("id_type", type);
                callout_handle->setArgument("id_value", id);

360 361 362
                // Call callouts
                HooksManager::callCallouts(Hooks.hook_index_host4_identifier_,
                                           *callout_handle);
363

364 365
                callout_handle->getArgument("id_type", type);
                callout_handle->getArgument("id_value", id);
366

367 368
                if ((callout_handle->getStatus() == CalloutHandle::NEXT_STEP_CONTINUE) &&
                    !id.empty()) {
369

370 371
                    LOG_DEBUG(packet4_logger, DBGLVL_TRACE_BASIC, DHCP4_FLEX_ID)
                        .arg(Host::getIdentifierAsText(type, &id[0], id.size()));
372

373
                    context_->addHostIdentifier(type, id);
374 375
                }
                break;
376
            }
377 378 379 380 381 382
        default:
            ;
        }
    }
}

383 384
void
Dhcpv4Exchange::setReservedClientClasses() {
385
    if (context_->currentHost() && query_) {
386
        BOOST_FOREACH(const std::string& client_class,
387
                      context_->currentHost()->getClientClasses4()) {
388 389 390 391 392
            query_->addClass(client_class);
        }
    }
}

393 394
void
Dhcpv4Exchange::setReservedMessageFields() {
395
    ConstHostPtr host = context_->currentHost();
396 397 398 399 400 401
    // Nothing to do if host reservations not specified for this client.
    if (host) {
        if (!host->getNextServer().isV4Zero()) {
            resp_->setSiaddr(host->getNextServer());
        }

402 403 404 405
        std::string sname = host->getServerHostname();
        if (!sname.empty()) {
            resp_->setSname(reinterpret_cast<const uint8_t*>(sname.c_str()),
                            sname.size());
406 407
        }

408 409 410 411
        std::string bootfile = host->getBootFileName();
        if (!bootfile.empty()) {
            resp_->setFile(reinterpret_cast<const uint8_t*>(bootfile.c_str()),
                           bootfile.size());
412 413 414 415
        }
    }
}

416 417
const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_");

418
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast,
419
                     const bool direct_response_desired)
420
    : io_service_(new IOService()), shutdown_(true), alloc_engine_(), port_(port),
421
      use_bcast_(use_bcast) {
422

423
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
424
    try {
425 426 427
        // 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.
428
        if (port) {
429 430 431 432 433 434 435 436
            // 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);
437
        }
438

439 440 441 442
        // 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,
443
                                            false /* false = IPv4 */));
444

445 446
        /// @todo call loadLibraries() when handling configuration changes

447
    } catch (const std::exception &e) {
448
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
449 450 451
        shutdown_ = true;
        return;
    }
452

Tomek Mrugalski's avatar
Tomek Mrugalski committed
453
    shutdown_ = false;
454 455 456
}

Dhcpv4Srv::~Dhcpv4Srv() {
457 458 459 460 461 462
    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());
    }
463

464 465 466 467 468 469 470
    try {
        Dhcp4to6Ipc::instance().close();
    } catch(const std::exception& ex) {
        // Highly unlikely, but lets Report it but go on
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_DHCP4O6_ERROR).arg(ex.what());
    }

Tomek Mrugalski's avatar
Tomek Mrugalski committed
471
    IfaceMgr::instance().closeSockets();
Tomek Mrugalski's avatar
Tomek Mrugalski committed
472

473 474
    // The lease manager was instantiated during DHCPv4Srv configuration,
    // so we should clean up after ourselves.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
475
    LeaseMgrFactory::destroy();
476 477 478

    // Explicitly unload hooks
    HooksManager::getHooksManager().unloadLibraries();
479 480
}

481 482
void
Dhcpv4Srv::shutdown() {
483
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
484 485 486
    shutdown_ = true;
}

487
isc::dhcp::Subnet4Ptr
488
Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
489

490 491 492 493 494
    // DHCPv4-over-DHCPv6 is a special (and complex) case
    if (query->isDhcp4o6()) {
        return (selectSubnet4o6(query));
    }

495 496 497 498 499 500 501 502 503 504
    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();

505 506 507 508 509
    // 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
510
    // when communicating with the relay agent." (RFC 3527)
511
    //
512
    // Try first Relay Agent Link Selection sub-option
513 514
    OptionPtr rai = query->getOption(DHO_DHCP_AGENT_OPTIONS);
    if (rai) {
515 516 517 518 519 520 521 522
        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)) {
523
                    selector.option_select_ =
524
                        IOAddress::fromBytes(AF_INET, &link_select_buf[0]);
525 526 527
                }
            }
        }
528 529 530 531 532 533 534 535 536 537
    } 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();
            }
        }
538 539
    }

540 541 542 543
    CfgMgr& cfgmgr = CfgMgr::instance();
    subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet(selector);

    // Let's execute all callouts registered for subnet4_select
544
    if (HooksManager::calloutsPresent(Hooks.hook_index_subnet4_select_)) {
545 546 547 548 549
        CalloutHandlePtr callout_handle = getCalloutHandle(query);

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

550 551 552
        // Enable copying options from the packet within hook library.
        ScopedEnableOptionsCopy<Pkt4> query4_options_copy(query);

553 554 555 556 557 558 559 560
        // 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
561
        HooksManager::callCallouts(Hooks.hook_index_subnet4_select_,
562 563 564 565 566
                                   *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)
567
        if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
568
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
569 570
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
571 572 573
            return (Subnet4Ptr());
        }

574 575
        /// @todo: Add support for DROP status

576 577 578 579
        // Use whatever subnet was specified by the callout
        callout_handle->getArgument("subnet4", subnet);
    }

580 581
    if (subnet) {
        // Log at higher debug level that subnet has been found.
582
        LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
583 584 585 586
            .arg(query->getLabel())
            .arg(subnet->getID());
        // Log detailed information about the selected subnet at the
        // lower debug level.
587
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_DATA)
588 589 590 591
            .arg(query->getLabel())
            .arg(subnet->toText());

    } else {
592
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL,
593 594 595 596
                  DHCP4_SUBNET_SELECTION_FAILED)
            .arg(query->getLabel());
    }

597
    return (subnet);
598 599
}

600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619
isc::dhcp::Subnet4Ptr
Dhcpv4Srv::selectSubnet4o6(const Pkt4Ptr& query) const {

    Subnet4Ptr subnet;

    SubnetSelector selector;
    selector.ciaddr_ = query->getCiaddr();
    selector.giaddr_ = query->getGiaddr();
    selector.local_address_ = query->getLocalAddr();
    selector.client_classes_ = query->classes_;
    selector.iface_name_ = query->getIface();
    // Mark it as DHCPv4-over-DHCPv6
    selector.dhcp4o6_ = true;
    // Now the DHCPv6 part
    selector.remote_address_ = query->getRemoteAddr();
    selector.first_relay_linkaddr_ = IOAddress("::");

    // Handle a DHCPv6 relayed query
    Pkt4o6Ptr query4o6 = boost::dynamic_pointer_cast<Pkt4o6>(query);
    if (!query4o6) {
620
        isc_throw(Unexpected, "Can't get DHCP4o6 message");
621 622 623 624 625 626 627 628 629 630 631 632 633 634
    }
    const Pkt6Ptr& query6 = query4o6->getPkt6();

    // Initialize fields specific to relayed messages.
    if (query6 && !query6->relay_info_.empty()) {
        BOOST_REVERSE_FOREACH(Pkt6::RelayInfo relay, query6->relay_info_) {
            if (!relay.linkaddr_.isV6Zero() &&
                !relay.linkaddr_.isV6LinkLocal()) {
                selector.first_relay_linkaddr_ = relay.linkaddr_;
                break;
            }
        }
        selector.interface_id_ =
            query6->getAnyRelayOption(D6O_INTERFACE_ID,
635
                                      Pkt6::RELAY_GET_FIRST);
636 637
    }

Francis Dupont's avatar
Francis Dupont committed
638 639 640 641 642 643 644 645 646
    // If the Subnet Selection option is present, extract its value.
    OptionPtr sbnsel = query->getOption(DHO_SUBNET_SELECTION);
    if (sbnsel) {
        OptionCustomPtr oc = boost::dynamic_pointer_cast<OptionCustom>(sbnsel);
        if (oc) {
            selector.option_select_ = oc->readAddress();
        }
    }

647
    CfgMgr& cfgmgr = CfgMgr::instance();
Francis Dupont's avatar
Francis Dupont committed
648
    subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet4o6(selector);
649 650

    // Let's execute all callouts registered for subnet4_select
651
    if (HooksManager::calloutsPresent(Hooks.hook_index_subnet4_select_)) {
652 653 654 655 656 657 658 659 660 661 662 663 664
        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
665
        HooksManager::callCallouts(Hooks.hook_index_subnet4_select_,
666 667 668 669 670
                                   *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)
671
        if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
672
            LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
673 674
                      DHCP4_HOOK_SUBNET4_SELECT_SKIP)
                .arg(query->getLabel());
675 676 677
            return (Subnet4Ptr());
        }

678 679
        /// @todo: Add support for DROP status

680 681 682 683
        // Use whatever subnet was specified by the callout
        callout_handle->getArgument("subnet4", subnet);
    }

684 685
    if (subnet) {
        // Log at higher debug level that subnet has been found.
686
        LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED)
687 688 689 690
            .arg(query->getLabel())
            .arg(subnet->getID());
        // Log detailed information about the selected subnet at the
        // lower debug level.
691
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_DATA)
692 693 694 695
            .arg(query->getLabel())
            .arg(subnet->toText());

    } else {
696
        LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL,
697 698 699 700
                  DHCP4_SUBNET_SELECTION_FAILED)
            .arg(query->getLabel());
    }

701
    return (subnet);
702 703
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
704 705
Pkt4Ptr
Dhcpv4Srv::receivePacket(int timeout) {
706 707 708
    return (IfaceMgr::instance().receive4(timeout));
}

Tomek Mrugalski's avatar
Tomek Mrugalski committed
709 710
void
Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) {
711 712 713
    IfaceMgr::instance().send(packet);
}

714 715
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
716
    while (!shutdown_) {
717
        try {
Francis Dupont's avatar
Francis Dupont committed
718
            run_one();
719
            getIOService()->poll();
720
        } catch (const std::exception& e) {
721 722
            // General catch-all exception that are not caught by more specific
            // catches. This one is for exceptions derived from std::exception.
723
            LOG_ERROR(packet4_logger, DHCP4_PACKET_PROCESS_STD_EXCEPTION)
724
                .arg(e.what());
725 726 727 728
        } catch (...) {
            // General catch-all exception that are not caught by more specific
            // catches. This one is for other exceptions, not derived from
            // std::exception.
729
            LOG_ERROR(packet4_logger, DHCP4_PACKET_PROCESS_EXCEPTION);
730
        }
731 732 733 734
    }

    return (true);
}
735

Francis Dupont's avatar
Francis Dupont committed
736 737 738 739 740
void
Dhcpv4Srv::run_one() {
    // client's message and server's response
    Pkt4Ptr query;
    Pkt4Ptr rsp;
741

Francis Dupont's avatar
Francis Dupont committed
742
    try {
743 744 745 746
        // Set select() timeout to 1s. This value should not be modified
        // because it is important that the select() returns control
        // frequently so as the IOService can be polled for ready handlers.
        uint32_t timeout = 1;
Francis Dupont's avatar
Francis Dupont committed
747 748 749 750 751 752 753 754 755 756 757 758 759 760 761
        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());
762

763
        }
764 765 766 767 768
        // We used to log that the wait was interrupted, but this is no longer
        // the case. Our wait time is 1s now, so the lack of query packet more
        // likely means that nothing new appeared within a second, rather than
        // we were interrupted. And we don't want to print a message every
        // second.
769

Francis Dupont's avatar
Francis Dupont committed
770 771 772
    } catch (const SignalInterruptOnSelect) {
        // Packet reception interrupted because a signal has been received.
        // This is not an error because we might have received a SIGTERM,
Josh Soref's avatar
Josh Soref committed
773
        // SIGINT, SIGHUP or SIGCHLD which are handled by the server. For
Francis Dupont's avatar
Francis Dupont committed
774 775 776 777 778 779 780 781
        // 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());
    }
782

Francis Dupont's avatar
Francis Dupont committed
783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800
    // 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());
    }
801

Francis Dupont's avatar
Francis Dupont committed
802 803 804 805 806 807
    // 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;
    }
808

809
    processPacket(query, rsp);
810

811 812 813
    if (!rsp) {
        return;
    }
814

815 816 817 818 819 820
    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_)) {
821 822 823 824 825
            CalloutHandlePtr callout_handle = getCalloutHandle(query);

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

826 827 828
            // Enable copying options from the packet within hook library.
            ScopedEnableOptionsCopy<Pkt4> resp4_options_copy(rsp);

829
            // Pass incoming packet as argument
830
            callout_handle->setArgument("response4", rsp);
831 832

            // Call callouts
833
            HooksManager::callCallouts(Hooks.hook_index_buffer4_send_,
Tomek Mrugalski's avatar
Tomek Mrugalski committed
834
                                       *callout_handle);
835 836 837

            // Callouts decided to skip the next processing step. The next
            // processing step would to parse the packet, so skip at this
838
            // stage means drop.
839
            if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) {
840 841 842 843
                LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS,
                          DHCP4_HOOK_BUFFER_SEND_SKIP)
                    .arg(rsp->getLabel());
                return;
844 845
            }

846
            /// @todo: Add support for DROP status.
847

848
            callout_handle->getArgument("response4", rsp);
849 850
        }

851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876
        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());
    }
877
}
878

879
void
880
Dhcpv4Srv::processPacket(Pkt4Ptr& query, Pkt4Ptr& rsp) {
881 882
    // Log reception of the packet. We need to increase it early, as any
    // failures in unpacking will cause the packet to be dropped. We
883
    // will increase type specific statistic further down the road.
884 885 886 887 888 889 890 891 892 893
    // See processStatsReceived().
    isc::stats::StatsMgr::instance().addValue("pkt4-received",
                                              static_cast<int64_t>(1));

    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);
894

895 896
        // Delete previously set arguments
        callout_handle->deleteAllArguments();
897

898 899 900
        // Enable copying options from the packet within hook library.
        ScopedEnableOptionsCopy<Pkt4> query4_options_copy(query);

901 902
        // Pass incoming packet as argument
        callout_handle->setArgument("query4", query);
903

904 905 906
        // Call callouts
        HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_,
                                   *callout_handle);
907

908 909 910 911 912 913 914 915 916 917 918 919
        // 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;
        }
920

921
        callout_handle->getArgument("query4", query);
922

923 924
        /// @todo: add support for DROP status
    }
925

926 927 928
    // Unpack the packet information unless the buffer4_receive callouts
    // indicated they did it
    if (!skip_unpack) {
929
        try {
930 931 932 933 934
            LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_UNPACK)
                .arg(query->getRemoteAddr().toText())
                .arg(query->getLocalAddr().toText())
                .arg(query->getIface());
            query->unpack();
935
        } catch (const std::exception& e) {
936 937 938 939 940 941
            // 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())
942
                .arg(e.what());
943

Francis Dupont's avatar
Francis Dupont committed
944
            // Increase the statistics of parse failures and dropped packets.
945 946
            isc::stats::StatsMgr::instance().addValue("pkt4-parse-failed",
                                                      static_cast<int64_t>(1));
Tomek Mrugalski's avatar
Tomek Mrugalski committed
947
            isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop",
948
                                                      static_cast<int64_t>(1));
949
            return;
950
        }
951
    }
952

953 954
    // Update statistics accordingly for received packet.
    processStatsReceived(query);
955

956 957 958 959
    // 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);
960

961 962 963 964 965 966 967 968
    // 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;
    }
969

970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
    // 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
Francis Dupont's avatar
Francis Dupont committed
985
    if (HooksManager::calloutsPresent(Hooks.hook_index_pkt4_receive_)) {
986
        CalloutHandlePtr callout_handle = getCalloutHandle(query);
Tomek Mrugalski's avatar