dhcp4_srv.cc 20.4 KB
Newer Older
1
// Copyright (C) 2011-2012 Internet Systems Consortium, Inc. ("ISC")
2 3 4 5 6 7 8 9 10 11 12 13 14
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

15
#include <asiolink/io_address.h>
16
#include <dhcp/dhcp4.h>
17
#include <dhcp/iface_mgr.h>
18
#include <dhcp/option4_addrlst.h>
19
#include <dhcp/option_int.h>
20
#include <dhcp/pkt4.h>
21 22
#include <dhcp/duid.h>
#include <dhcp/hwaddr.h>
23 24
#include <dhcp4/dhcp4_log.h>
#include <dhcp4/dhcp4_srv.h>
25 26 27 28 29 30 31
#include <dhcpsrv/utils.h>
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/lease_mgr_factory.h>
#include <dhcpsrv/subnet.h>
#include <dhcpsrv/utils.h>
#include <dhcpsrv/addr_utilities.h>
32

33 34 35 36 37
#include <boost/algorithm/string/erase.hpp>

#include <iomanip>
#include <fstream>

38 39
using namespace isc;
using namespace isc::asiolink;
40 41 42
using namespace isc::dhcp;
using namespace isc::log;
using namespace std;
43

44 45
// These are hardcoded parameters. Currently this is a skeleton server that only
// grants those options and a single, fixed, hardcoded lease.
Tomek Mrugalski's avatar
Tomek Mrugalski committed
46 47 48
const std::string HARDCODED_GATEWAY = "192.0.2.1";
const std::string HARDCODED_DNS_SERVER = "192.0.2.2";
const std::string HARDCODED_DOMAIN_NAME = "isc.example.com";
49

50
Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const char* dbconfig) {
51
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port);
52
    try {
53
        // First call to instance() will create IfaceMgr (it's a singleton)
54 55
        // it may throw something if things go wrong
        IfaceMgr::instance();
56

57 58 59 60 61
        if (port) {
            // open sockets only if port is non-zero. Port 0 is used
            // for non-socket related testing.
            IfaceMgr::instance().openSockets4(port);
        }
62

63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
        string srvid_file = CfgMgr::instance().getDataDir() + "/" + string(SERVER_ID_FILE);
        if (loadServerID(srvid_file)) {
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_SERVERID_LOADED)
                .arg(srvid_file);
        } else {
            generateServerID();
            LOG_INFO(dhcp4_logger, DHCP4_SERVERID_GENERATED)
                .arg(srvidToString(getServerID()))
                .arg(srvid_file);

            if (!writeServerID(srvid_file)) {
                LOG_WARN(dhcp4_logger, DHCP4_SERVERID_WRITE_FAIL)
                    .arg(srvid_file);
            }

        }
79

80 81 82 83 84 85 86 87 88
        // Instantiate LeaseMgr
        LeaseMgrFactory::create(dbconfig);
        LOG_INFO(dhcp4_logger, DHCP4_DB_BACKEND_STARTED)
            .arg(LeaseMgrFactory::instance().getType())
            .arg(LeaseMgrFactory::instance().getName());

        // Instantiate allocation engine
        alloc_engine_.reset(new AllocEngine(AllocEngine::ALLOC_ITERATIVE, 100));

89
    } catch (const std::exception &e) {
90
        LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what());
91 92 93
        shutdown_ = true;
        return;
    }
94

Tomek Mrugalski's avatar
Tomek Mrugalski committed
95
    shutdown_ = false;
96 97 98
}

Dhcpv4Srv::~Dhcpv4Srv() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
99
    IfaceMgr::instance().closeSockets();
100 101
}

102
void Dhcpv4Srv::shutdown() {
103
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST);
104 105 106
    shutdown_ = true;
}

107 108
bool
Dhcpv4Srv::run() {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
109
    while (!shutdown_) {
110 111 112
        /// @todo: calculate actual timeout once we have lease database
        int timeout = 1000;

Tomek Mrugalski's avatar
Tomek Mrugalski committed
113
        // client's message and server's response
114
        Pkt4Ptr query;
Tomek Mrugalski's avatar
Tomek Mrugalski committed
115
        Pkt4Ptr rsp;
116

117 118 119 120 121 122
        try {
            query = IfaceMgr::instance().receive4(timeout);
        } catch (const std::exception& e) {
            LOG_ERROR(dhcp4_logger, DHCP4_PACKET_RECEIVE_FAIL).arg(e.what());
        }

123
        if (query) {
Tomek Mrugalski's avatar
Tomek Mrugalski committed
124 125
            try {
                query->unpack();
126

Tomek Mrugalski's avatar
Tomek Mrugalski committed
127
            } catch (const std::exception& e) {
128 129 130
                // Failed to parse the packet.
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL,
                          DHCP4_PACKET_PARSE_FAIL).arg(e.what());
131 132
                continue;
            }
133
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_RECEIVED)
134 135 136
                      .arg(serverReceivedPacketName(query->getType()))
                      .arg(query->getType())
                      .arg(query->getIface());
137 138 139
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_QUERY_DATA)
                      .arg(query->toText());

140 141 142 143
            switch (query->getType()) {
            case DHCPDISCOVER:
                rsp = processDiscover(query);
                break;
144

145 146 147
            case DHCPREQUEST:
                rsp = processRequest(query);
                break;
148

149 150 151
            case DHCPRELEASE:
                processRelease(query);
                break;
152

153 154 155
            case DHCPDECLINE:
                processDecline(query);
                break;
156

157 158 159
            case DHCPINFORM:
                processInform(query);
                break;
160

161
            default:
162 163 164 165
                // Only action is to output a message if debug is enabled,
                // and that will be covered by the debug statement before
                // the "switch" statement.
                ;
166 167 168
            }

            if (rsp) {
169 170 171 172 173 174 175 176 177
                if (rsp->getRemoteAddr().toText() == "0.0.0.0") {
                    rsp->setRemoteAddr(query->getRemoteAddr());
                }
                if (!rsp->getHops()) {
                    rsp->setRemotePort(DHCP4_CLIENT_PORT);
                } else {
                    rsp->setRemotePort(DHCP4_SERVER_PORT);
                }

178 179 180 181 182
                rsp->setLocalAddr(query->getLocalAddr());
                rsp->setLocalPort(DHCP4_SERVER_PORT);
                rsp->setIface(query->getIface());
                rsp->setIndex(query->getIndex());

183 184 185
                LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA,
                          DHCP4_RESPONSE_DATA)
                          .arg(rsp->getType()).arg(rsp->toText());
186 187

                if (rsp->pack()) {
188 189
                    try {
                        IfaceMgr::instance().send(rsp);
Marcin Siodelski's avatar
Marcin Siodelski committed
190 191
                    } catch (const std::exception& e) {
                        LOG_ERROR(dhcp4_logger, DHCP4_PACKET_SEND_FAIL).arg(e.what());
192
                    }
193
                } else {
194
                    LOG_ERROR(dhcp4_logger, DHCP4_PACK_FAIL);
195 196 197
                }
            }
        }
198 199 200 201 202 203
    }

    return (true);
}

bool Dhcpv4Srv::loadServerID(const std::string& file_name) {
204

205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231
    // load content of the file into a string
    fstream f(file_name.c_str(), ios::in);
    if (!f.is_open()) {
        return (false);
    }

    string hex_string;
    f >> hex_string;
    f.close();

    // remove any spaces
    boost::algorithm::erase_all(hex_string, " ");

    try {
        IOAddress addr(hex_string);

        if (addr.getFamily() != AF_INET) {
            return (false);
        }

        // Now create server-id option
        serverid_.reset(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER, addr));

    } catch(...) {
        // any kind of malformed input (empty string, IPv6 address, complete
        // garbate etc.)
        return (false);
232 233 234 235 236
    }

    return (true);
}

237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299
void Dhcpv4Srv::generateServerID() {

    const IfaceMgr::IfaceCollection& ifaces = IfaceMgr::instance().getIfaces();

    // Let's find suitable interface.
    for (IfaceMgr::IfaceCollection::const_iterator iface = ifaces.begin();
         iface != ifaces.end(); ++iface) {

        // Let's don't use loopback.
        if (iface->flag_loopback_) {
            continue;
        }

        // Let's skip downed interfaces. It is better to use working ones.
        if (!iface->flag_up_) {
            continue;
        }

        const IfaceMgr::AddressCollection addrs = iface->getAddresses();

        for (IfaceMgr::AddressCollection::const_iterator addr = addrs.begin();
             addr != addrs.end(); ++addr) {
            if (addr->getFamily() != AF_INET) {
                continue;
            }

            serverid_ = OptionPtr(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                                     *addr));
            return;
        }


    }

    isc_throw(BadValue, "No suitable interfaces for server-identifier found");
}

bool Dhcpv4Srv::writeServerID(const std::string& file_name) {
    fstream f(file_name.c_str(), ios::out | ios::trunc);
    if (!f.good()) {
        return (false);
    }
    f << srvidToString(getServerID());
    f.close();
}

string Dhcpv4Srv::srvidToString(const OptionPtr& srvid) {
    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());
300 301
}

302
void Dhcpv4Srv::copyDefaultFields(const Pkt4Ptr& question, Pkt4Ptr& answer) {
303 304 305
    answer->setIface(question->getIface());
    answer->setIndex(question->getIndex());
    answer->setCiaddr(question->getCiaddr());
306

307 308
    answer->setSiaddr(IOAddress("0.0.0.0")); // explictly set this to 0
    answer->setHops(question->getHops());
309 310

    // copy MAC address
311
    answer->setHWAddr(question->getHWAddr());
312 313

    // relay address
314 315 316
    answer->setGiaddr(question->getGiaddr());

    if (question->getGiaddr().toText() != "0.0.0.0") {
317
        // relayed traffic
318
        answer->setRemoteAddr(question->getGiaddr());
319 320
    } else {
        // direct traffic
321
        answer->setRemoteAddr(question->getRemoteAddr());
322 323
    }

324
    // Let's copy client-id to response. See RFC6842.
325 326 327 328
    OptionPtr client_id = question->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (client_id) {
        answer->addOption(client_id);
    }
329 330
}

331 332
void Dhcpv4Srv::appendDefaultOptions(Pkt4Ptr& msg, uint8_t msg_type) {
    OptionPtr opt;
333 334

    // add Message Type Option (type 53)
335
    msg->setType(msg_type);
336

Tomek Mrugalski's avatar
Tomek Mrugalski committed
337
    // DHCP Server Identifier (type 54)
338
    msg->addOption(getServerID());
Tomek Mrugalski's avatar
Tomek Mrugalski committed
339

340 341 342 343
    // more options will be added here later
}


344 345
void Dhcpv4Srv::appendRequestedOptions(Pkt4Ptr& msg) {
    OptionPtr opt;
346

Tomek Mrugalski's avatar
Tomek Mrugalski committed
347 348
    // Domain name (type 15)
    vector<uint8_t> domain(HARDCODED_DOMAIN_NAME.begin(), HARDCODED_DOMAIN_NAME.end());
349
    opt = OptionPtr(new Option(Option::V4, DHO_DOMAIN_NAME, domain));
Tomek Mrugalski's avatar
Tomek Mrugalski committed
350 351
    msg->addOption(opt);
    // TODO: Add Option_String class
352

Tomek Mrugalski's avatar
Tomek Mrugalski committed
353
    // DNS servers (type 6)
354
    opt = OptionPtr(new Option4AddrLst(DHO_DOMAIN_NAME_SERVERS, IOAddress(HARDCODED_DNS_SERVER)));
Tomek Mrugalski's avatar
Tomek Mrugalski committed
355 356
    msg->addOption(opt);
}
357

358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375
void Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {

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

        // perhaps this should be logged on some higher level? This is most likely
        // configuration bug.
        LOG_ERROR(dhcp4_logger, DHCP4_SUBNET_SELECTION_FAILED)
            .arg(question->getRemoteAddr().toText())
            .arg(serverReceivedPacketName(question->getType()));
376
        answer->setType(DHCPNAK);
377 378 379
        answer->setYiaddr(IOAddress("0.0.0.0"));
        return;
    }
380

381 382 383
    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_SELECTED)
        .arg(subnet->toText());

384 385 386 387 388 389 390
    // Get client-id option
    ClientIdPtr client_id;
    OptionPtr opt = question->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (opt) {
        client_id = ClientIdPtr(new ClientId(opt->getData()));
    }
    // client-id is not mandatory in DHCPv4
391

392
    IOAddress hint = question->getYiaddr();
393

394
    HWAddrPtr hwaddr = question->getHWAddr();
395

396 397 398 399 400 401
    // "Fake" allocation is processing of DISCOVER message. We pretend to do an
    // allocation, but we do not put the lease in the database. That is ok,
    // because we do not guarantee that the user will get that exact lease. If
    // the user selects this server to do actual allocation (i.e. sends REQUEST)
    // it should include this hint. That will help us during the actual lease
    // allocation.
402
    bool fake_allocation = (question->getType() == DHCPDISCOVER);
403 404 405 406 407 408 409 410 411

    // Use allocation engine to pick a lease for this client. Allocation engine
    // will try to honour the hint, but it is just a hint - some other address
    // may be used instead. If fake_allocation is set to false, the lease will
    // be inserted into the LeaseMgr as well.
    Lease4Ptr lease = alloc_engine_->allocateAddress4(subnet, client_id, hwaddr,
                                                      hint, fake_allocation);

    if (lease) {
412 413
        // We have a lease! Let's set it in the packet and send it back to
        // the client.
414 415
        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, fake_allocation?
                  DHCP4_LEASE_ADVERT:DHCP4_LEASE_ALLOC)
Tomek Mrugalski's avatar
Tomek Mrugalski committed
416
            .arg(lease->addr_.toText())
417
            .arg(client_id?client_id->toText():"(no client-id)")
Tomek Mrugalski's avatar
Tomek Mrugalski committed
418
            .arg(hwaddr?hwaddr->toText():"(no hwaddr info)");
419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448

        answer->setYiaddr(lease->addr_);

        // IP Address Lease time (type 51)
        opt = OptionPtr(new Option(Option::V4, DHO_DHCP_LEASE_TIME));
        opt->setUint32(lease->valid_lft_);
        answer->addOption(opt);

        // @todo: include real router information here
        // Router (type 3)
        opt = OptionPtr(new Option4AddrLst(DHO_ROUTERS, IOAddress(HARDCODED_GATEWAY)));
        answer->addOption(opt);

        // Subnet mask (type 1)
        answer->addOption(getNetmaskOption(subnet));

        // @todo: send renew timer option (T1, option 58)
        // @todo: send rebind timer option (T2, option 59)

    } else {
        // Allocation engine did not allocate a lease. The engine logged
        // cause of that failure. The only thing left is to insert
        // status code to pass the sad news to the client.

        LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, fake_allocation?
                  DHCP4_LEASE_ADVERT_FAIL:DHCP4_LEASE_ALLOC_FAIL)
            .arg(client_id?client_id->toText():"(no client-id)")
            .arg(hwaddr?hwaddr->toText():"(no hwaddr info)")
            .arg(hint.toText());

449
        answer->setType(DHCPNAK);
450 451 452 453 454 455 456 457 458 459 460 461 462
        answer->setYiaddr(IOAddress("0.0.0.0"));
    }
}

OptionPtr Dhcpv4Srv::getNetmaskOption(const Subnet4Ptr& subnet) {
    uint32_t netmask = getNetmask4(subnet->get().second);

    OptionPtr opt(new OptionInt<uint32_t>(Option::V4,
                  DHO_SUBNET_MASK, netmask));

    return (opt);
}

463 464
Pkt4Ptr Dhcpv4Srv::processDiscover(Pkt4Ptr& discover) {
    Pkt4Ptr offer = Pkt4Ptr
Tomek Mrugalski's avatar
Tomek Mrugalski committed
465
        (new Pkt4(DHCPOFFER, discover->getTransid()));
466

Tomek Mrugalski's avatar
Tomek Mrugalski committed
467 468 469 470
    copyDefaultFields(discover, offer);
    appendDefaultOptions(offer, DHCPOFFER);
    appendRequestedOptions(offer);

471
    assignLease(discover, offer);
472 473

    return (offer);
474 475
}

476 477
Pkt4Ptr Dhcpv4Srv::processRequest(Pkt4Ptr& request) {
    Pkt4Ptr ack = Pkt4Ptr
478 479 480 481
        (new Pkt4(DHCPACK, request->getTransid()));

    copyDefaultFields(request, ack);
    appendDefaultOptions(ack, DHCPACK);
Tomek Mrugalski's avatar
Tomek Mrugalski committed
482
    appendRequestedOptions(ack);
483

484
    assignLease(request, ack);
485 486

    return (ack);
487 488
}

489
void Dhcpv4Srv::processRelease(Pkt4Ptr& release) {
490 491

    // Try to find client-id
492 493 494 495 496 497
    ClientIdPtr client_id;
    OptionPtr opt = release->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
    if (opt) {
        client_id = ClientIdPtr(new ClientId(opt->getData()));
    }

498 499 500 501 502 503 504 505 506 507 508 509
    try {
        // Do we have a lease for that particular address?
        Lease4Ptr lease = LeaseMgrFactory::instance().getLease4(release->getYiaddr());

        if (!lease) {
            // No such lease - bogus release
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE_FAIL_NO_LEASE)
                .arg(release->getYiaddr().toText())
                .arg(release->getHWAddr()->toText())
                .arg(client_id ? client_id->toText() : "(no client-id)");
            return;
        }
510

511 512 513 514 515 516 517 518 519 520
        // Does the hardware address match? We don't want one client releasing
        // second client's leases.
        if (lease->hwaddr_ != release->getHWAddr()->hwaddr_) {
            // @todo: Print hwaddr from lease as part of ticket #2589
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE_FAIL_WRONG_HWADDR)
                .arg(release->getYiaddr().toText())
                .arg(client_id ? client_id->toText() : "(no client-id)")
                .arg(release->getHWAddr()->toText());
            return;
        }
521

522 523 524 525 526 527 528 529 530
        // Does the lease have client-id info? If it has, then check it with what
        // the client sent us.
        if (lease->client_id_ && client_id && *lease->client_id_ != *client_id) {
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE_FAIL_WRONG_CLIENT_ID)
                .arg(release->getYiaddr().toText())
                .arg(client_id->toText())
                .arg(lease->client_id_->toText());
            return;
        }
531

532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552
        // Ok, hw and client-id match - let's release the lease.
        if (LeaseMgrFactory::instance().deleteLease(lease->addr_)) {

            // Release successful - we're done here
            LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE)
                .arg(lease->addr_.toText())
                .arg(client_id ? client_id->toText() : "(no client-id)")
                .arg(release->getHWAddr()->toText());
        } else {

            // Release failed -
            LOG_ERROR(dhcp4_logger, DHCP4_RELEASE_FAIL)
                .arg(lease->addr_.toText())
                .arg(client_id ? client_id->toText() : "(no client-id)")
                .arg(release->getHWAddr()->toText());
        }
    } catch (const isc::Exception& ex) {
        // Rethrow the exception with a bit more data.
        LOG_ERROR(dhcp4_logger, DHCP4_RELEASE_EXCEPTION)
            .arg(ex.what())
            .arg(release->getYiaddr());
553 554
    }

555
}
556

557
void Dhcpv4Srv::processDecline(Pkt4Ptr& decline) {
558 559 560
    /// TODO: Implement this.
}

561
Pkt4Ptr Dhcpv4Srv::processInform(Pkt4Ptr& inform) {
562
    /// TODO: Currently implemented echo mode. Implement this for real
563 564
    return (inform);
}
565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595

const char*
Dhcpv4Srv::serverReceivedPacketName(uint8_t type) {
    static const char* DISCOVER = "DISCOVER";
    static const char* REQUEST = "REQUEST";
    static const char* RELEASE = "RELEASE";
    static const char* DECLINE = "DECLINE";
    static const char* INFORM = "INFORM";
    static const char* UNKNOWN = "UNKNOWN";

    switch (type) {
    case DHCPDISCOVER:
        return (DISCOVER);

    case DHCPREQUEST:
        return (REQUEST);

    case DHCPRELEASE:
        return (RELEASE);

    case DHCPDECLINE:
        return (DECLINE);

    case DHCPINFORM:
        return (INFORM);

    default:
        ;
    }
    return (UNKNOWN);
}
596 597 598

Subnet4Ptr Dhcpv4Srv::selectSubnet(const Pkt4Ptr& question) {

599 600 601 602 603 604 605 606 607 608 609
    // Is this relayed message?
    IOAddress relay = question->getGiaddr();
    if (relay.toText() == "0.0.0.0") {

        // Yes: Use relay address to select subnet
        return (CfgMgr::instance().getSubnet4(relay));
    } else {

        // No: Use client's address to select subnet
        return (CfgMgr::instance().getSubnet4(question->getRemoteAddr()));
    }
610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634
}

void Dhcpv4Srv::sanityCheck(const Pkt4Ptr& pkt, RequirementLevel serverid) {
    OptionPtr server_id = pkt->getOption(DHO_DHCP_SERVER_IDENTIFIER);
    switch (serverid) {
    case FORBIDDEN:
        if (server_id) {
            isc_throw(RFCViolation, "Server-id option was not expected, but "
                      << "received in " << serverReceivedPacketName(pkt->getType()));
        }
        break;

    case MANDATORY:
        if (!server_id) {
            isc_throw(RFCViolation, "Server-id option was expected, but not "
                      " received in message "
                      << serverReceivedPacketName(pkt->getType()));
        }
        break;

    case OPTIONAL:
        // do nothing here
        ;
    }
}