// Copyright (C) 2011-2016 Internet Systems Consortium, Inc. ("ISC") // // 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/. #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_MYSQL #include #endif #ifdef HAVE_PGSQL #include #endif #ifdef HAVE_CQL #include #endif #include #include #include #include #include using namespace isc; using namespace isc::asiolink; using namespace isc::cryptolink; using namespace isc::dhcp; using namespace isc::dhcp_ddns; using namespace isc::hooks; using namespace isc::log; using namespace isc::stats; using namespace std; /// Structure that holds registered hook indexes struct Dhcp4Hooks { 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 /// Constructor that registers hook points for DHCPv4 engine Dhcp4Hooks() { 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"); } }; // 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. Dhcp4Hooks Hooks; namespace isc { namespace dhcp { Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine, const Pkt4Ptr& query, const Subnet4Ptr& subnet) : alloc_engine_(alloc_engine), query_(query), resp_(), context_(new AllocEngine::ClientContext4()) { 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"); } // Create response message. initResponse(); // Select subnet for the query message. context_->subnet_ = subnet; // Hardware address. context_->hwaddr_ = query->getHWAddr(); // Pointer to client's query. context_->query_ = query; // Set client identifier if the match-client-id flag is enabled (default). // 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) { if (subnet->getMatchClientId()) { 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()); } // Find static reservations if not disabled for our subnet. if (subnet->getHostReservationMode() != Subnet::HR_DISABLED) { // Before we can check for static reservations, we need to prepare a set // of identifiers to be used for this. setHostIdentifiers(); // Check for static reservations. alloc_engine->findReservation(*context_); } } }; void Dhcpv4Exchange::initResponse() { uint8_t resp_type = 0; switch (getQuery()->getType()) { case DHCPDISCOVER: resp_type = DHCPOFFER; break; case DHCPREQUEST: case DHCPINFORM: resp_type = DHCPACK; break; default: ; } // Only create a response if one is required. if (resp_type > 0) { resp_.reset(new Pkt4(resp_type, getQuery()->getTransid())); copyDefaultFields(); copyDefaultOptions(); if (getQuery()->isDhcp4o6()) { initResponse4o6(); } } } void Dhcpv4Exchange::initResponse4o6() { Pkt4o6Ptr query = boost::dynamic_pointer_cast(getQuery()); if (!query) { return; } 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)); } void Dhcpv4Exchange::copyDefaultFields() { resp_->setIface(query_->getIface()); resp_->setIndex(query_->getIndex()); // explicitly set this to 0 resp_->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS()); // 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); } // Copy flags from the request to the response per RFC 2131 resp_->setFlags(query_->getFlags()); } void Dhcpv4Exchange::copyDefaultOptions() { // Let's copy client-id to response. See RFC6842. // It is possible to disable RFC6842 to keep backward compatibility bool echo = CfgMgr::instance().echoClientId(); OptionPtr client_id = query_->getOption(DHO_DHCP_CLIENT_IDENTIFIER); if (client_id && echo) { resp_->addOption(client_id); } // If 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); } // 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); } } void Dhcpv4Exchange::setHostIdentifiers() { const ConstCfgHostOperationsPtr cfg = CfgMgr::instance().getCurrentCfg()->getCfgHostOperations4(); // Collect host identifiers. The identifiers are stored in order of preference. // The server will use them in that order to search for host reservations. 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& 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(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; case Host::IDENT_CLIENT_ID: if (context_->clientid_) { const std::vector& vec = context_->clientid_->getDuid(); if (!vec.empty()) { context_->addHostIdentifier(id_type, vec); } } break; default: ; } } } const std::string Dhcpv4Srv::VENDOR_CLASS_PREFIX("VENDOR_CLASS_"); Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const bool use_bcast, const bool direct_response_desired) : shutdown_(true), alloc_engine_(), port_(port), use_bcast_(use_bcast) { LOG_DEBUG(dhcp4_logger, DBG_DHCP4_START, DHCP4_OPEN_SOCKET).arg(port); try { // 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. if (port) { // 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); } // 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, false /* false = IPv4 */)); /// @todo call loadLibraries() when handling configuration changes } catch (const std::exception &e) { LOG_ERROR(dhcp4_logger, DHCP4_SRV_CONSTRUCT_ERROR).arg(e.what()); shutdown_ = true; return; } shutdown_ = false; } Dhcpv4Srv::~Dhcpv4Srv() { 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()); } 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()); } IfaceMgr::instance().closeSockets(); // The lease manager was instantiated during DHCPv4Srv configuration, // so we should clean up after ourselves. LeaseMgrFactory::destroy(); // Explicitly unload hooks HooksManager::getHooksManager().unloadLibraries(); } void Dhcpv4Srv::shutdown() { LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_SHUTDOWN_REQUEST); shutdown_ = true; } isc::dhcp::Subnet4Ptr Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const { // DHCPv4-over-DHCPv6 is a special (and complex) case if (query->isDhcp4o6()) { return (selectSubnet4o6(query)); } 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(); // 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) // // Try first Relay Agent Link Selection sub-option OptionPtr rai = query->getOption(DHO_DHCP_AGENT_OPTIONS); if (rai) { OptionCustomPtr rai_custom = boost::dynamic_pointer_cast(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)) { selector.option_select_ = IOAddress::fromBytes(AF_INET, &link_select_buf[0]); } } } } else { // Or Subnet Selection option OptionPtr sbnsel = query->getOption(DHO_SUBNET_SELECTION); if (sbnsel) { OptionCustomPtr oc = boost::dynamic_pointer_cast(sbnsel); if (oc) { selector.option_select_ = oc->readAddress(); } } } CfgMgr& cfgmgr = CfgMgr::instance(); subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet(selector); // Let's execute all callouts registered for subnet4_select if (HooksManager::calloutsPresent(Hooks.hook_index_subnet4_select_)) { CalloutHandlePtr callout_handle = getCalloutHandle(query); // We're reusing callout_handle from previous calls callout_handle->deleteAllArguments(); // Enable copying options from the packet within hook library. ScopedEnableOptionsCopy query4_options_copy(query); // 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(Hooks.hook_index_subnet4_select_, *callout_handle); // Callouts decided to skip this step. This means that no subnet // will be selected. Packet processing will continue, but it will // be severely limited (i.e. only global options will be assigned) if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) { LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_SUBNET4_SELECT_SKIP) .arg(query->getLabel()); return (Subnet4Ptr()); } /// @todo: Add support for DROP status // Use whatever subnet was specified by the callout callout_handle->getArgument("subnet4", subnet); } if (subnet) { // Log at higher debug level that subnet has been found. LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED) .arg(query->getLabel()) .arg(subnet->getID()); // Log detailed information about the selected subnet at the // lower debug level. LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_DATA) .arg(query->getLabel()) .arg(subnet->toText()); } else { LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_SUBNET_SELECTION_FAILED) .arg(query->getLabel()); } return (subnet); } 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(query); if (!query4o6) { isc_throw(Unexpected, "Can't get DHCP4o6 message"); } 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, Pkt6::RELAY_GET_FIRST); } // 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(sbnsel); if (oc) { selector.option_select_ = oc->readAddress(); } } CfgMgr& cfgmgr = CfgMgr::instance(); subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet4o6(selector); // Let's execute all callouts registered for subnet4_select if (HooksManager::calloutsPresent(Hooks.hook_index_subnet4_select_)) { 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(Hooks.hook_index_subnet4_select_, *callout_handle); // Callouts decided to skip this step. This means that no subnet // will be selected. Packet processing will continue, but it will // be severely limited (i.e. only global options will be assigned) if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) { LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_SUBNET4_SELECT_SKIP) .arg(query->getLabel()); return (Subnet4Ptr()); } /// @todo: Add support for DROP status // Use whatever subnet was specified by the callout callout_handle->getArgument("subnet4", subnet); } if (subnet) { // Log at higher debug level that subnet has been found. LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC_DATA, DHCP4_SUBNET_SELECTED) .arg(query->getLabel()) .arg(subnet->getID()); // Log detailed information about the selected subnet at the // lower debug level. LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_DATA) .arg(query->getLabel()) .arg(subnet->toText()); } else { LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_SUBNET_SELECTION_FAILED) .arg(query->getLabel()); } return (subnet); } Pkt4Ptr Dhcpv4Srv::receivePacket(int timeout) { return (IfaceMgr::instance().receive4(timeout)); } void Dhcpv4Srv::sendPacket(const Pkt4Ptr& packet) { IfaceMgr::instance().send(packet); } bool Dhcpv4Srv::run() { while (!shutdown_) { try { run_one(); } catch (const std::exception& e) { // 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_STD_EXCEPTION) .arg(e.what()); } 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); } } return (true); } void Dhcpv4Srv::run_one() { // client's message and server's response Pkt4Ptr query; Pkt4Ptr rsp; 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()); } else { LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_BUFFER_WAIT_INTERRUPTED) .arg(timeout); } } 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()); } // 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()); } // 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; } processPacket(query, rsp); if (!rsp) { return; } 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); // Delete previously set arguments callout_handle->deleteAllArguments(); // Enable copying options from the packet within hook library. ScopedEnableOptionsCopy resp4_options_copy(rsp); // Pass incoming packet as argument callout_handle->setArgument("response4", rsp); // Call callouts HooksManager::callCallouts(Hooks.hook_index_buffer4_send_, *callout_handle); // 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; } /// @todo: Add support for DROP status. callout_handle->getArgument("response4", rsp); } LOG_DEBUG(packet4_logger, DBG_DHCP4_BASIC, DHCP4_PACKET_SEND) .arg(rsp->getLabel()) .arg(rsp->getName()) .arg(static_cast(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(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()); } } void Dhcpv4Srv::processPacket(Pkt4Ptr& query, Pkt4Ptr& rsp) { // 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 statistic further down the road. // See processStatsReceived(). isc::stats::StatsMgr::instance().addValue("pkt4-received", static_cast(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); // Delete previously set arguments callout_handle->deleteAllArguments(); // Enable copying options from the packet within hook library. ScopedEnableOptionsCopy query4_options_copy(query); // Pass incoming packet as argument callout_handle->setArgument("query4", query); // Call callouts HooksManager::callCallouts(Hooks.hook_index_buffer4_receive_, *callout_handle); // 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; } callout_handle->getArgument("query4", query); /// @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()); // Increase the statistics of parse failues and dropped packets. isc::stats::StatsMgr::instance().addValue("pkt4-parse-failed", static_cast(1)); isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop", static_cast(1)); return; } } // Update statistics accordingly for received packet. processStatsReceived(query); // 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); // 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(1)); return; } // 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(Hooks.hook_index_pkt4_receive_)) { CalloutHandlePtr callout_handle = getCalloutHandle(query); // Delete previously set arguments callout_handle->deleteAllArguments(); // Enable copying options from the packet within hook library. ScopedEnableOptionsCopy query4_options_copy(query); // Pass incoming packet as argument callout_handle->setArgument("query4", query); // Call callouts HooksManager::callCallouts(Hooks.hook_index_pkt4_receive_, *callout_handle); // Callouts decided to skip the next processing step. The next // processing step would to process the packet, so skip at this // stage means drop. if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_SKIP) { LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_PACKET_RCVD_SKIP) .arg(query->getLabel()); return; } /// @todo: Add support for DROP status callout_handle->getArgument("query4", query); } 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. ; } } 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()); // Increase the statistic of dropped packets. isc::stats::StatsMgr::instance().addValue("pkt4-receive-drop", static_cast(1)); } if (!rsp) { return; } // Specifies if server should do the packing bool skip_pack = false; // Execute all callouts registered for pkt4_send if (HooksManager::calloutsPresent(Hooks.hook_index_pkt4_send_)) { CalloutHandlePtr callout_handle = getCalloutHandle(query); // Delete all previous arguments callout_handle->deleteAllArguments(); // Clear skip flag if it was set in previous callouts callout_handle->setStatus(CalloutHandle::NEXT_STEP_CONTINUE); // Enable copying options from the query and response packets within // hook library. ScopedEnableOptionsCopy query_resp_options_copy(query, rsp); // Set our response callout_handle->setArgument("response4", rsp); // Also pass the corresponding query packet as argument callout_handle->setArgument("query4", query); // Call all installed callouts HooksManager::callCallouts(Hooks.hook_index_pkt4_send_, *callout_handle); // 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; } /// @todo: Add support for DROP status } if (!skip_pack) { try { 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()); } } } string Dhcpv4Srv::srvidToString(const OptionPtr& srvid) { if (!srvid) { isc_throw(BadValue, "NULL pointer passed to srvidToString()"); } boost::shared_ptr generated = boost::dynamic_pointer_cast(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()); } void Dhcpv4Srv::appendServerID(Dhcpv4Exchange& ex) { // 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. /// @todo: perhaps we should consider some more sophisticated server id /// generation, but for the current use cases, it should be ok. OptionPtr opt_srvid(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER, ex.getResponse()->getLocalAddr())); ex.getResponse()->addOption(opt_srvid); } void Dhcpv4Srv::buildCfgOptionList(Dhcpv4Exchange& ex) { CfgOptionList& co_list = ex.getCfgOptionList(); // Retrieve subnet. Subnet4Ptr subnet = ex.getContext()->subnet_; if (!subnet) { // All methods using the CfgOptionList object return soon when // there is no subnet so do the same return; } // Firstly, host specific options. const ConstHostPtr& host = ex.getContext()->host_; if (host && !host->getCfgOption4()->empty()) { co_list.push_back(host->getCfgOption4()); } // Secondly, subnet configured options. if (!subnet->getCfgOption()->empty()) { 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 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 LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_UNCONFIGURED) .arg(ex.getQuery()->getLabel()) .arg(*cclass); } // Skip it continue; } if (ccdef->getCfgOption()->empty()) { // Skip classes which don't configure options continue; } co_list.push_back(ccdef->getCfgOption()); } // Last global options if (!CfgMgr::instance().getCurrentCfg()->getCfgOption()->empty()) { co_list.push_back(CfgMgr::instance().getCurrentCfg()->getCfgOption()); } } void Dhcpv4Srv::appendRequestedOptions(Dhcpv4Exchange& ex) { // Get the subnet relevant for the client. We will need it // to get the options associated with it. Subnet4Ptr subnet = ex.getContext()->subnet_; // 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; } // Unlikely short cut const CfgOptionList& co_list = ex.getCfgOptionList(); if (co_list.empty()) { return; } Pkt4Ptr query = ex.getQuery(); // try to get the 'Parameter Request List' option which holds the // codes of requested options. OptionUint8ArrayPtr option_prl = boost::dynamic_pointer_cast< OptionUint8Array>(query->getOption(DHO_DHCP_PARAMETER_REQUEST_LIST)); // If there is no PRL option in the message from the client then // there is nothing to do. if (!option_prl) { return; } Pkt4Ptr resp = ex.getResponse(); // Get the codes of requested options. const std::vector& 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::const_iterator opt = requested_opts.begin(); opt != requested_opts.end(); ++opt) { // Add nothing when it is already there if (!resp->getOption(*opt)) { // 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 if (desc.option_) { resp->addOption(desc.option_); break; } } } } } void Dhcpv4Srv::appendRequestedVendorOptions(Dhcpv4Exchange& ex) { // Get the configured subnet suitable for the incoming packet. Subnet4Ptr subnet = ex.getContext()->subnet_; // 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; } // Unlikely short cut const CfgOptionList& co_list = ex.getCfgOptionList(); if (co_list.empty()) { return; } // Try to get the vendor option boost::shared_ptr vendor_req = boost::dynamic_pointer_cast< OptionVendor>(ex.getQuery()->getOption(DHO_VIVSO_SUBOPTIONS)); if (!vendor_req) { return; } uint32_t vendor_id = vendor_req->getVendorId(); // Let's try to get ORO within that vendor-option /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other /// vendors may have different policies. OptionUint8ArrayPtr oro = boost::dynamic_pointer_cast(vendor_req->getOption(DOCSIS3_V4_ORO)); // Option ORO not found. Don't do anything then. if (!oro) { return; } boost::shared_ptr vendor_rsp(new OptionVendor(Option::V4, vendor_id)); // Get the list of options that client requested. bool added = false; const std::vector& requested_opts = oro->getValues(); for (std::vector::const_iterator code = requested_opts.begin(); code != requested_opts.end(); ++code) { if (!vendor_rsp->getOption(*code)) { 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; } } } if (added) { ex.getResponse()->addOption(vendor_rsp); } } } void Dhcpv4Srv::appendBasicOptions(Dhcpv4Exchange& ex) { // 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 }; static size_t required_options_size = sizeof(required_options) / sizeof(required_options[0]); // Get the subnet. Subnet4Ptr subnet = ex.getContext()->subnet_; if (!subnet) { return; } // Unlikely short cut const CfgOptionList& co_list = ex.getCfgOptionList(); if (co_list.empty()) { return; } Pkt4Ptr resp = ex.getResponse(); // 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) { OptionPtr opt = resp->getOption(required_options[i]); if (!opt) { // Check whether option has been configured. 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; } } } } } void Dhcpv4Srv::processClientName(Dhcpv4Exchange& ex) { // 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. try { Pkt4Ptr resp = ex.getResponse(); Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast (ex.getQuery()->getOption(DHO_FQDN)); if (fqdn) { LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_FQDN_PROCESS) .arg(ex.getQuery()->getLabel()); processClientFqdnOption(ex); } else { LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL, DHCP4_CLIENT_HOSTNAME_PROCESS) .arg(ex.getQuery()->getLabel()); processHostnameOption(ex); } } catch (const Exception& e) { // In some rare cases it is possible that the client's name processing // fails. For example, the Hostname option may be malformed, or there // may be an error in the server's logic which would cause multiple // attempts to add the same option to the response message. This // error message aggregates all these errors so they can be diagnosed // from the log. We don't want to throw an exception here because, // it will impact the processing of the whole packet. We rather want // the processing to continue, even if the client's name is wrong. LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_NAME_PROC_FAIL) .arg(ex.getQuery()->getLabel()) .arg(e.what()); } } void Dhcpv4Srv::processClientFqdnOption(Dhcpv4Exchange& ex) { // Obtain the FQDN option from the client's message. Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast< Option4ClientFqdn>(ex.getQuery()->getOption(DHO_FQDN)); LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_FQDN_DATA) .arg(ex.getQuery()->getLabel()) .arg(fqdn->toText()); // Create the DHCPv4 Client FQDN Option to be included in the server's // response to a client. Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn)); // Set the server S, N, and O flags based on client's flags and // current configuration. D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr(); d2_mgr.adjustFqdnFlags(*fqdn, *fqdn_resp); // Carry over the client's E flag. fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E, fqdn->getFlag(Option4ClientFqdn::FLAG_E)); if (ex.getContext()->host_ && !ex.getContext()->host_->getHostname().empty()) { D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr(); fqdn_resp->setDomainName(d2_mgr.qualifyName(ex.getContext()->host_->getHostname(), true), Option4ClientFqdn::FULL); } else { // Adjust the domain name based on domain name value and type sent by the // client and current configuration. d2_mgr.adjustDomainName(*fqdn, *fqdn_resp); } // Add FQDN option to the response message. Note that, there may be some // cases when server may choose not to include the FQDN option in a // response to a client. In such cases, the FQDN should be removed from the // outgoing message. In theory we could cease to include the FQDN option // in this function until it is confirmed that it should be included. // However, we include it here for simplicity. Functions used to acquire // lease for a client will scan the response message for FQDN and if it // is found they will take necessary actions to store the FQDN information // in the lease database as well as to generate NameChangeRequests to DNS. // If we don't store the option in the response message, we will have to // propagate it in the different way to the functions which acquire the // lease. This would require modifications to the API of this class. LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_RESPONSE_FQDN_DATA) .arg(ex.getQuery()->getLabel()) .arg(fqdn_resp->toText()); ex.getResponse()->addOption(fqdn_resp); } void Dhcpv4Srv::processHostnameOption(Dhcpv4Exchange& ex) { // Fetch D2 configuration. D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr(); // Do nothing if the DNS updates are disabled. if (!d2_mgr.ddnsEnabled()) { return; } D2ClientConfig::ReplaceClientNameMode replace_name_mode = d2_mgr.getD2ClientConfig()->getReplaceClientNameMode(); // Obtain the Hostname option from the client's message. OptionStringPtr opt_hostname = boost::dynamic_pointer_cast (ex.getQuery()->getOption(DHO_HOST_NAME)); // If we don't have a hostname then either we'll supply it or do nothing. if (!opt_hostname) { // If we're configured to supply it then add it to the response. // Use the root domain to signal later on that we should replace it. if (replace_name_mode == D2ClientConfig::RCM_ALWAYS || replace_name_mode == D2ClientConfig::RCM_WHEN_NOT_PRESENT) { LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_GENERATE_FQDN) .arg(ex.getQuery()->getLabel()); OptionStringPtr opt_hostname_resp(new OptionString(Option::V4, DHO_HOST_NAME, ".")); ex.getResponse()->addOption(opt_hostname_resp); } return; } // Client sent us a hostname option so figure out what to do with it. LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_CLIENT_HOSTNAME_DATA) .arg(ex.getQuery()->getLabel()) .arg(opt_hostname->getValue()); std::string hostname = isc::util::str::trim(opt_hostname->getValue()); unsigned int label_count = OptionDataTypeUtil::getLabelCount(hostname); // The hostname option sent by the client should be at least 1 octet long. // If it isn't we ignore this option. (Per RFC 2131, section 3.14) /// @todo It would be more liberal to accept this and let it fall into /// the case of replace or less than two below. if (label_count == 0) { LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_EMPTY_HOSTNAME) .arg(ex.getQuery()->getLabel()); return; } // Copy construct the hostname provided by the client. It is entirely // possible that we will use the hostname option provided by the client // to perform the DNS update and we will send the same option to him to // indicate that we accepted this hostname. OptionStringPtr opt_hostname_resp(new OptionString(*opt_hostname)); // The hostname option may be unqualified or fully qualified. The lab_count // holds the number of labels for the name. The number of 1 means that // there is only root label "." (even for unqualified names, as the // getLabelCount function treats each name as a fully qualified one). // By checking the number of labels present in the hostname we may infer // whether client has sent the fully qualified or unqualified hostname. // If there is a hostname reservation for this client, use it. if (ex.getContext()->host_ && !ex.getContext()->host_->getHostname().empty()) { opt_hostname_resp->setValue(d2_mgr.qualifyName(ex.getContext()->host_->getHostname(), false)); } else if ((replace_name_mode == D2ClientConfig::RCM_ALWAYS || replace_name_mode == D2ClientConfig::RCM_WHEN_PRESENT) || label_count < 2) { // Set to root domain to signal later on that we should replace it. // DHO_HOST_NAME is a string option which cannot be empty. /// @todo We may want to reconsider whether it is appropriate for the /// client to send a root domain name as a Hostname. There are /// also extensions to the auto generation of the client's name, /// e.g. conversion to the puny code which may be considered at some /// point. /// For now, we just remain liberal and expect that the DNS will handle /// conversion if needed and possible. opt_hostname_resp->setValue("."); } else if (label_count == 2) { // If there are two labels, it means that the client has specified // the unqualified name. We have to concatenate the unqualified name // with the domain name. The false value passed as a second argument // indicates that the trailing dot should not be appended to the // hostname. We don't want to append the trailing dot because // we don't know whether the hostname is partial or not and some // clients do not handle the hostnames with the trailing dot. opt_hostname_resp->setValue(d2_mgr.qualifyName(hostname, false)); } LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_RESPONSE_HOSTNAME_DATA) .arg(ex.getQuery()->getLabel()) .arg(opt_hostname_resp->getValue()); ex.getResponse()->addOption(opt_hostname_resp); } void Dhcpv4Srv::createNameChangeRequests(const Lease4Ptr& lease, const Lease4Ptr& old_lease) { if (!lease) { isc_throw(isc::Unexpected, "NULL lease specified when creating NameChangeRequest"); } else if (!old_lease || (old_lease && !lease->hasIdenticalFqdn(*old_lease))) { // We may need to generate the NameChangeRequest for the new lease. It // will be generated only if hostname is set and if forward or reverse // update has been requested. queueNCR(CHG_ADD, lease); } } void Dhcpv4Srv::assignLease(Dhcpv4Exchange& ex) { // Get the pointers to the query and the response messages. Pkt4Ptr query = ex.getQuery(); Pkt4Ptr resp = ex.getResponse(); // Get the context. AllocEngine::ClientContext4Ptr ctx = ex.getContext(); // Subnet should have been already selected when the context was created. Subnet4Ptr subnet = ctx->subnet_; 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). // Perhaps this should be logged on some higher level? LOG_ERROR(bad_packet4_logger, DHCP4_PACKET_NAK_0001) .arg(query->getLabel()) .arg(query->getRemoteAddr().toText()) .arg(query->getName()); resp->setType(DHCPNAK); resp->setYiaddr(IOAddress::IPV4_ZERO_ADDRESS()); return; } // Set up siaddr. Perhaps assignLease is not the best place to call this // as siaddr has nothing to do with a lease, but otherwise we would have // to select subnet twice (performance hit) or update too many functions // at once. /// @todo: move subnet selection to a common code resp->setSiaddr(subnet->getSiaddr()); // Get the server identifier. It will be used to determine the state // of the client. OptionCustomPtr opt_serverid = boost::dynamic_pointer_cast< OptionCustom>(query->getOption(DHO_DHCP_SERVER_IDENTIFIER)); // Check if the client has sent a requested IP address option or // ciaddr. OptionCustomPtr opt_requested_address = boost::dynamic_pointer_cast< OptionCustom>(query->getOption(DHO_DHCP_REQUESTED_ADDRESS)); IOAddress hint(IOAddress::IPV4_ZERO_ADDRESS()); if (opt_requested_address) { hint = opt_requested_address->readAddress(); } else if (!query->getCiaddr().isV4Zero()) { hint = query->getCiaddr(); } HWAddrPtr hwaddr = query->getHWAddr(); // "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. bool fake_allocation = (query->getType() == DHCPDISCOVER); // Get client-id. It is not mandatory in DHCPv4. ClientIdPtr client_id = ex.getContext()->clientid_; // If there is no server id and there is a Requested IP Address option // the client is in the INIT-REBOOT state in which the server has to // determine whether the client's notion of the address is correct // and whether the client is known, i.e., has a lease. if (!fake_allocation && !opt_serverid && opt_requested_address) { LOG_INFO(lease4_logger, DHCP4_INIT_REBOOT) .arg(query->getLabel()) .arg(hint.toText()); Lease4Ptr lease; if (client_id) { lease = LeaseMgrFactory::instance().getLease4(*client_id, subnet->getID()); } if (!lease && hwaddr) { lease = LeaseMgrFactory::instance().getLease4(*hwaddr, subnet->getID()); } // Check the first error case: unknown client. We check this before // validating the address sent because we don't want to respond if // we don't know this client. if (!lease || !lease->belongsToClient(hwaddr, client_id)) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_NO_LEASE_INIT_REBOOT) .arg(query->getLabel()) .arg(hint.toText()); ex.deleteResponse(); return; } // We know this client so we can now check if his notion of the // IP address is correct. if (lease && (lease->addr_ != hint)) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_NAK_0002) .arg(query->getLabel()) .arg(hint.toText()); resp->setType(DHCPNAK); resp->setYiaddr(IOAddress::IPV4_ZERO_ADDRESS()); return; } } CalloutHandlePtr callout_handle = getCalloutHandle(query); std::string hostname; bool fqdn_fwd = false; bool fqdn_rev = false; OptionStringPtr opt_hostname; Option4ClientFqdnPtr fqdn = boost::dynamic_pointer_cast< Option4ClientFqdn>(resp->getOption(DHO_FQDN)); if (fqdn) { hostname = fqdn->getDomainName(); CfgMgr::instance().getD2ClientMgr().getUpdateDirections(*fqdn, fqdn_fwd, fqdn_rev); } else { opt_hostname = boost::dynamic_pointer_cast (resp->getOption(DHO_HOST_NAME)); if (opt_hostname) { hostname = opt_hostname->getValue(); // DHO_HOST_NAME is string option which cannot be blank, // we use "." to know we should replace it with a fully // generated name. The local string variable needs to be // blank in logic below. if (hostname == ".") { hostname = ""; } /// @todo It could be configurable what sort of updates the /// server is doing when Hostname option was sent. fqdn_fwd = true; fqdn_rev = true; } } // We need to set these values in the context as they haven't been set yet. ctx->requested_address_ = hint; ctx->fwd_dns_update_ = fqdn_fwd; ctx->rev_dns_update_ = fqdn_rev; ctx->hostname_ = hostname; ctx->fake_allocation_ = fake_allocation; ctx->callout_handle_ = callout_handle; Lease4Ptr lease = alloc_engine_->allocateLease4(*ctx); if (lease) { // We have a lease! Let's set it in the packet and send it back to // the client. LOG_INFO(lease4_logger, fake_allocation ? DHCP4_LEASE_ADVERT : DHCP4_LEASE_ALLOC) .arg(query->getLabel()) .arg(lease->addr_.toText()); resp->setYiaddr(lease->addr_); /// @todo The server should check what ciaddr the client has supplied /// in ciaddr. Currently the ciaddr is ignored except for the subnet /// selection. If the client supplied an invalid address, the server /// will also return an invalid address here. if (!fake_allocation) { // If this is a renewing client it will set a ciaddr which the // server may include in the response. If this is a new allocation // the client will set ciaddr to 0 and this will also be propagated // to the server's resp. resp->setCiaddr(query->getCiaddr()); } // If there has been Client FQDN or Hostname option sent, but the // hostname is empty, it means that server is responsible for // generating the entire hostname for the client. The example of the // client's name, generated from the IP address is: host-192-0-2-3. if ((fqdn || opt_hostname) && lease->hostname_.empty()) { // Note that if we have received the hostname option, rather than // Client FQDN the trailing dot is not appended to the generated // hostname because some clients don't handle the trailing dot in // the hostname. Whether the trailing dot is appended or not is // controlled by the second argument to the generateFqdn(). lease->hostname_ = CfgMgr::instance().getD2ClientMgr() .generateFqdn(lease->addr_, static_cast(fqdn)); LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL, DHCP4_RESPONSE_HOSTNAME_GENERATE) .arg(query->getLabel()) .arg(lease->hostname_); // The operations below are rather safe, but we want to catch // any potential exceptions (e.g. invalid lease database backend // implementation) and log an error. try { if (!fake_allocation) { // The lease update should be safe, because the lease should // be already in the database. In most cases the exception // would be thrown if the lease was missing. LeaseMgrFactory::instance().updateLease4(lease); } // The name update in the option should be also safe, // because the generated name is well formed. if (fqdn) { fqdn->setDomainName(lease->hostname_, Option4ClientFqdn::FULL); } else if (opt_hostname) { opt_hostname->setValue(lease->hostname_); } } catch (const Exception& ex) { LOG_ERROR(ddns4_logger, DHCP4_NAME_GEN_UPDATE_FAIL) .arg(query->getLabel()) .arg(lease->hostname_) .arg(ex.what()); } } // IP Address Lease time (type 51) OptionPtr opt(new OptionUint32(Option::V4, DHO_DHCP_LEASE_TIME, lease->valid_lft_)); resp->addOption(opt); // Subnet mask (type 1) resp->addOption(getNetmaskOption(subnet)); // renewal-timer (type 58) if (!subnet->getT1().unspecified()) { OptionUint32Ptr t1(new OptionUint32(Option::V4, DHO_DHCP_RENEWAL_TIME, subnet->getT1())); resp->addOption(t1); } // rebind timer (type 59) if (!subnet->getT2().unspecified()) { OptionUint32Ptr t2(new OptionUint32(Option::V4, DHO_DHCP_REBINDING_TIME, subnet->getT2())); resp->addOption(t2); } // Create NameChangeRequests if DDNS is enabled and this is a // real allocation. if (!fake_allocation && CfgMgr::instance().ddnsEnabled()) { try { LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL, DHCP4_NCR_CREATE) .arg(query->getLabel()); createNameChangeRequests(lease, ctx->old_lease_); } catch (const Exception& ex) { LOG_ERROR(ddns4_logger, DHCP4_NCR_CREATION_FAILED) .arg(query->getLabel()) .arg(ex.what()); } } } else { // Allocation engine did not allocate a lease. The engine logged // cause of that failure. LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, fake_allocation ? DHCP4_PACKET_NAK_0003 : DHCP4_PACKET_NAK_0004) .arg(query->getLabel()) .arg(query->getCiaddr().toText()) .arg(opt_requested_address ? opt_requested_address->readAddress().toText() : "(no address)"); resp->setType(DHCPNAK); resp->setYiaddr(IOAddress::IPV4_ZERO_ADDRESS()); resp->delOption(DHO_FQDN); resp->delOption(DHO_HOST_NAME); } } void Dhcpv4Srv::adjustIfaceData(Dhcpv4Exchange& ex) { adjustRemoteAddr(ex); // Initialize the pointers to the client's message and the server's // response. Pkt4Ptr query = ex.getQuery(); Pkt4Ptr response = ex.getResponse(); // For the non-relayed message, the destination port is the client's port. // For the relayed message, the server/relay port is a destination unless // the message is DHCPINFORM. // Note that the call to this function may throw if invalid combination // of hops and giaddr is found (hops = 0 if giaddr = 0 and hops != 0 if // giaddr != 0). The exception will propagate down and eventually cause the // packet to be discarded. const bool server_port = query->isRelayed() && ((query->getType() == DHCPINFORM) ? query->getCiaddr().isV4Zero() : true); response->setRemotePort(server_port ? DHCP4_SERVER_PORT : DHCP4_CLIENT_PORT); IOAddress local_addr = query->getLocalAddr(); // In many cases the query is sent to a broadcast address. This address // apears as a local address in the query message. We can't simply copy // this address to a response message and use it as a source address. // Instead we will need to use the address assigned to the interface // on which the query has been received. In other cases, we will just // use this address as a source address for the response. // Do the same for DHCPv4-over-DHCPv6 exchanges. if (local_addr.isV4Bcast() || query->isDhcp4o6()) { SocketInfo sock_info = IfaceMgr::instance().getSocket(*query); local_addr = sock_info.addr_; } // We assume that there is an appropriate socket bound to this address // and that the address is correct. This is safe assumption because // the local address of the query is set when the query is received. // The query sent to an incorrect address wouldn't have been received. // However, if socket is closed for this address between the reception // of the query and sending a response, the IfaceMgr should detect it // and return an error. response->setLocalAddr(local_addr); // In many cases the query is sent to a broadcast address. This address // appears as a local address in the query message. Therefore we can't // simply copy local address from the query and use it as a source // address for the response. Instead, we have to check what address our // socket is bound to and use it as a source address. This operation // may throw if for some reason the socket is closed. /// @todo Consider an optimization that we use local address from /// the query if this address is not broadcast. response->setLocalPort(DHCP4_SERVER_PORT); response->setIface(query->getIface()); response->setIndex(query->getIndex()); } void Dhcpv4Srv::adjustRemoteAddr(Dhcpv4Exchange& ex) { // Initialize the pointers to the client's message and the server's // response. Pkt4Ptr query = ex.getQuery(); Pkt4Ptr response = ex.getResponse(); // DHCPv4-over-DHCPv6 is simple if (query->isDhcp4o6()) { response->setRemoteAddr(query->getRemoteAddr()); return; } // The DHCPINFORM is slightly different than other messages in a sense // that the server should always unicast the response to the ciaddr. // It appears however that some clients don't set the ciaddr. We still // want to provision these clients and we do what we can't to send the // packet to the address where client can receive it. if (query->getType() == DHCPINFORM) { // If client adheres to RFC2131 it will set the ciaddr and in this // case we always unicast our response to this address. if (!query->getCiaddr().isV4Zero()) { response->setRemoteAddr(query->getCiaddr()); // If we received DHCPINFORM via relay and the ciaddr is not set we // will try to send the response via relay. The caveat is that the // relay will not have any idea where to forward the packet because // the yiaddr is likely not set. So, the broadcast flag is set so // as the response may be broadcast. } else if (query->isRelayed()) { response->setRemoteAddr(query->getGiaddr()); response->setFlags(response->getFlags() | BOOTP_BROADCAST); // If there is no ciaddr and no giaddr the only thing we can do is // to use the source address of the packet. } else { response->setRemoteAddr(query->getRemoteAddr()); } // Remote address is now set so return. return; } // If received relayed message, server responds to the relay address. if (query->isRelayed()) { // The client should set the ciaddr when sending the DHCPINFORM // but in case he didn't, the relay may not be able to determine the // address of the client, because yiaddr is not set when responding // to Confirm and the only address available was the source address // of the client. The source address is however not used here because // the message is relayed. Therefore, we set the BROADCAST flag so // as the relay can broadcast the packet. if ((query->getType() == DHCPINFORM) && query->getCiaddr().isV4Zero()) { response->setFlags(BOOTP_BROADCAST); } response->setRemoteAddr(query->getGiaddr()); // If giaddr is 0 but client set ciaddr, server should unicast the // response to ciaddr. } else if (!query->getCiaddr().isV4Zero()) { response->setRemoteAddr(query->getCiaddr()); // We can't unicast the response to the client when sending NAK, // because we haven't allocated address for him. Therefore, // NAK is broadcast. } else if (response->getType() == DHCPNAK) { response->setRemoteAddr(IOAddress::IPV4_BCAST_ADDRESS()); // If yiaddr is set it means that we have created a lease for a client. } else if (!response->getYiaddr().isV4Zero()) { // If the broadcast bit is set in the flags field, we have to // send the response to broadcast address. Client may have requested it // because it doesn't support reception of messages on the interface // which doesn't have an address assigned. The other case when response // must be broadcasted is when our server does not support responding // directly to a client without address assigned. const bool bcast_flag = ((query->getFlags() & Pkt4::FLAG_BROADCAST_MASK) != 0); if (!IfaceMgr::instance().isDirectResponseSupported() || bcast_flag) { response->setRemoteAddr(IOAddress::IPV4_BCAST_ADDRESS()); // Client cleared the broadcast bit and we support direct responses // so we should unicast the response to a newly allocated address - // yiaddr. } else { response->setRemoteAddr(response ->getYiaddr()); } // In most cases, we should have the remote address found already. If we // found ourselves at this point, the rational thing to do is to respond // to the address we got the query from. } else { response->setRemoteAddr(query->getRemoteAddr()); } } OptionPtr Dhcpv4Srv::getNetmaskOption(const Subnet4Ptr& subnet) { uint32_t netmask = getNetmask4(subnet->get().second); OptionPtr opt(new OptionInt(Option::V4, DHO_SUBNET_MASK, netmask)); return (opt); } Pkt4Ptr Dhcpv4Srv::processDiscover(Pkt4Ptr& discover) { sanityCheck(discover, FORBIDDEN); Dhcpv4Exchange ex(alloc_engine_, discover, selectSubnet(discover)); // If DHCPDISCOVER message contains the FQDN or Hostname option, server // may respond to the client with the appropriate FQDN or Hostname // option to indicate that whether it will take responsibility for // updating DNS when the client sends DHCPREQUEST message. processClientName(ex); assignLease(ex); if (!ex.getResponse()) { // The offer is empty so return it *now*! return (Pkt4Ptr()); } // Adding any other options makes sense only when we got the lease. if (!ex.getResponse()->getYiaddr().isV4Zero()) { buildCfgOptionList(ex); appendRequestedOptions(ex); appendRequestedVendorOptions(ex); // There are a few basic options that we always want to // include in the response. If client did not request // them we append them for him. appendBasicOptions(ex); } else { // If the server can't offer an address, it drops the packet. return (Pkt4Ptr()); } // Set the src/dest IP address, port and interface for the outgoing // packet. adjustIfaceData(ex); appendServerID(ex); /// @todo: decide whether we want to add a new hook point for /// doing class specific processing. if (!vendorClassSpecificProcessing(ex)) { /// @todo add more verbosity here LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, DHCP4_DISCOVER_CLASS_PROCESSING_FAILED) .arg(discover->getLabel()); } return (ex.getResponse()); } Pkt4Ptr Dhcpv4Srv::processRequest(Pkt4Ptr& request) { /// @todo Uncomment this (see ticket #3116) /// sanityCheck(request, MANDATORY); Dhcpv4Exchange ex(alloc_engine_, request, selectSubnet(request)); // If DHCPREQUEST message contains the FQDN or Hostname option, server // should respond to the client with the appropriate FQDN or Hostname // option to indicate if it takes responsibility for the DNS updates. // This is performed by the function below. processClientName(ex); // Note that we treat REQUEST message uniformly, regardless if this is a // first request (requesting for new address), renewing existing address // or even rebinding. assignLease(ex); if (!ex.getResponse()) { // The ack is empty so return it *now*! return (Pkt4Ptr()); } // Adding any other options makes sense only when we got the lease. if (!ex.getResponse()->getYiaddr().isV4Zero()) { buildCfgOptionList(ex); appendRequestedOptions(ex); appendRequestedVendorOptions(ex); // There are a few basic options that we always want to // include in the response. If client did not request // them we append them for him. appendBasicOptions(ex); } // Set the src/dest IP address, port and interface for the outgoing // packet. adjustIfaceData(ex); appendServerID(ex); /// @todo: decide whether we want to add a new hook point for /// doing class specific processing. if (!vendorClassSpecificProcessing(ex)) { /// @todo add more verbosity here LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, DHCP4_REQUEST_CLASS_PROCESSING_FAILED) .arg(ex.getQuery()->getLabel()); } return (ex.getResponse()); } void Dhcpv4Srv::processRelease(Pkt4Ptr& release) { /// @todo Uncomment this (see ticket #3116) /// sanityCheck(release, MANDATORY); // Try to find client-id. Note that for the DHCPRELEASE we don't check if the // match-client-id configuration parameter is disabled because this parameter // is configured for subnets and we don't select subnet for the DHCPRELEASE. // Bogus clients usually generate new client identifiers when they first // connect to the network, so whatever client identifier has been used to // acquire the lease, the client identifier carried in the DHCPRELEASE is // likely to be the same and the lease will be correctly identified in the // lease database. If supplied client identifier differs from the one used // to acquire the lease then the lease will remain in the database and // simply expire. ClientIdPtr client_id; OptionPtr opt = release->getOption(DHO_DHCP_CLIENT_IDENTIFIER); if (opt) { client_id = ClientIdPtr(new ClientId(opt->getData())); } try { // Do we have a lease for that particular address? Lease4Ptr lease = LeaseMgrFactory::instance().getLease4(release->getCiaddr()); if (!lease) { // No such lease - bogus release LOG_DEBUG(lease4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE_FAIL_NO_LEASE) .arg(release->getLabel()) .arg(release->getCiaddr().toText()); return; } if (!lease->belongsToClient(release->getHWAddr(), client_id)) { LOG_DEBUG(lease4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE_FAIL_WRONG_CLIENT) .arg(release->getLabel()) .arg(release->getCiaddr().toText()); return; } bool skip = false; // Execute all callouts registered for lease4_release if (HooksManager::calloutsPresent(Hooks.hook_index_lease4_release_)) { CalloutHandlePtr callout_handle = getCalloutHandle(release); // Delete all previous arguments callout_handle->deleteAllArguments(); // Enable copying options from the packet within hook library. ScopedEnableOptionsCopy query4_options_copy(release); // Pass the original packet callout_handle->setArgument("query4", release); // Pass the lease to be updated callout_handle->setArgument("lease4", lease); // Call all installed callouts HooksManager::callCallouts(Hooks.hook_index_lease4_release_, *callout_handle); // 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) { skip = true; LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_LEASE4_RELEASE_SKIP) .arg(release->getLabel()); } /// @todo add support for DROP status } // Callout didn't indicate to skip the release process. Let's release // the lease. if (!skip) { bool success = LeaseMgrFactory::instance().deleteLease(lease->addr_); if (success) { // Release successful LOG_INFO(lease4_logger, DHCP4_RELEASE) .arg(release->getLabel()) .arg(lease->addr_.toText()); // Need to decrease statistic for assigned addresses. StatsMgr::instance().addValue( StatsMgr::generateName("subnet", lease->subnet_id_, "assigned-addresses"), static_cast(-1)); // Remove existing DNS entries for the lease, if any. queueNCR(CHG_REMOVE, lease); } else { // Release failed LOG_ERROR(lease4_logger, DHCP4_RELEASE_FAIL) .arg(release->getLabel()) .arg(lease->addr_.toText()); } } } catch (const isc::Exception& ex) { LOG_ERROR(lease4_logger, DHCP4_RELEASE_EXCEPTION) .arg(release->getLabel()) .arg(release->getCiaddr()) .arg(ex.what()); } } void Dhcpv4Srv::processDecline(Pkt4Ptr& decline) { // Server-id is mandatory in DHCPDECLINE (see table 5, RFC2131) /// @todo Uncomment this (see ticket #3116) // sanityCheck(decline, MANDATORY); // Client is supposed to specify the address being declined in // Requested IP address option, but must not set its ciaddr. // (again, see table 5 in RFC2131). OptionCustomPtr opt_requested_address = boost::dynamic_pointer_cast< OptionCustom>(decline->getOption(DHO_DHCP_REQUESTED_ADDRESS)); if (!opt_requested_address) { isc_throw(RFCViolation, "Mandatory 'Requested IP address' option missing" "in DHCPDECLINE sent from " << decline->getLabel()); } IOAddress addr(opt_requested_address->readAddress()); // We could also extract client's address from ciaddr, but that's clearly // against RFC2131. // Now we need to check whether this address really belongs to the client // that attempts to decline it. const Lease4Ptr lease = LeaseMgrFactory::instance().getLease4(addr); if (!lease) { // Client tried to decline an address, but we don't have a lease for // that address. Let's ignore it. // // We could assume that we're recovering from a mishandled migration // to a new server and mark the address as declined, but the window of // opportunity for that to be useful is small and the attack vector // would be pretty severe. LOG_WARN(dhcp4_logger, DHCP4_DECLINE_LEASE_NOT_FOUND) .arg(addr.toText()).arg(decline->getLabel()); return; } // Get client-id, if available. OptionPtr opt_clientid = decline->getOption(DHO_DHCP_CLIENT_IDENTIFIER); ClientIdPtr client_id; if (opt_clientid) { client_id.reset(new ClientId(opt_clientid->getData())); } // Check if the client attempted to decline a lease it doesn't own. if (!lease->belongsToClient(decline->getHWAddr(), client_id)) { // Get printable hardware addresses string client_hw = decline->getHWAddr() ? decline->getHWAddr()->toText(false) : "(none)"; string lease_hw = lease->hwaddr_ ? lease->hwaddr_->toText(false) : "(none)"; // Get printable client-ids string client_id_txt = client_id ? client_id->toText() : "(none)"; string lease_id_txt = lease->client_id_ ? lease->client_id_->toText() : "(none)"; // Print the warning and we're done here. LOG_WARN(dhcp4_logger, DHCP4_DECLINE_LEASE_MISMATCH) .arg(addr.toText()).arg(decline->getLabel()) .arg(client_hw).arg(lease_hw).arg(client_id_txt).arg(lease_id_txt); return; } // Ok, all is good. The client is reporting its own address. Let's // process it. declineLease(lease, decline); } void Dhcpv4Srv::declineLease(const Lease4Ptr& lease, const Pkt4Ptr& decline) { // Let's check if there are hooks installed for decline4 hook point. // If they are, let's pass the lease and client's packet. If the hook // sets status to drop, we reject this Decline. if (HooksManager::calloutsPresent(Hooks.hook_index_lease4_decline_)) { CalloutHandlePtr callout_handle = getCalloutHandle(decline); // Delete previously set arguments callout_handle->deleteAllArguments(); // Enable copying options from the packet within hook library. ScopedEnableOptionsCopy query4_options_copy(decline); // Pass incoming Decline and the lease to be declined. callout_handle->setArgument("lease4", lease); callout_handle->setArgument("query4", decline); // Call callouts HooksManager::callCallouts(Hooks.hook_index_lease4_decline_, *callout_handle); // Check if callouts decided to drop the packet. If any of them did, // we will drop the packet. if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_DROP) { LOG_DEBUG(hooks_logger, DBG_DHCP4_HOOKS, DHCP4_HOOK_DECLINE_SKIP) .arg(decline->getLabel()).arg(lease->addr_.toText()); return; } } // Remove existing DNS entries for the lease, if any. // queueNCR will do the necessary checks and will skip the update, if not needed. queueNCR(CHG_REMOVE, lease); // Bump up the statistics. // Per subnet declined addresses counter. StatsMgr::instance().addValue( StatsMgr::generateName("subnet", lease->subnet_id_, "declined-addresses"), static_cast(1)); // Global declined addresses counter. StatsMgr::instance().addValue("declined-addresses", static_cast(1)); // We do not want to decrease the assigned-addresses at this time. While // technically a declined address is no longer allocated, the primary usage // of the assigned-addresses statistic is to monitor pool utilization. Most // people would forget to include declined-addresses in the calculation, // and simply do assigned-addresses/total-addresses. This would have a bias // towards under-representing pool utilization, if we decreased allocated // immediately after receiving DHCPDECLINE, rather than later when we recover // the address. // @todo: Call hooks. // We need to disassociate the lease from the client. Once we move a lease // to declined state, it is no longer associated with the client in any // way. lease->decline(CfgMgr::instance().getCurrentCfg()->getDeclinePeriod()); LeaseMgrFactory::instance().updateLease4(lease); LOG_INFO(lease4_logger, DHCP4_DECLINE_LEASE).arg(lease->addr_.toText()) .arg(decline->getLabel()).arg(lease->valid_lft_); } Pkt4Ptr Dhcpv4Srv::processInform(Pkt4Ptr& inform) { // DHCPINFORM MUST not include server identifier. sanityCheck(inform, FORBIDDEN); Dhcpv4Exchange ex(alloc_engine_, inform, selectSubnet(inform)); Pkt4Ptr ack = ex.getResponse(); buildCfgOptionList(ex); appendRequestedOptions(ex); appendRequestedVendorOptions(ex); appendBasicOptions(ex); adjustIfaceData(ex); // There are cases for the DHCPINFORM that the server receives it via // relay but will send the response to the client's unicast address // carried in the ciaddr. In this case, the giaddr and hops field should // be cleared (these fields were copied by the copyDefaultFields function). // Also Relay Agent Options should be removed if present. if (ack->getRemoteAddr() != inform->getGiaddr()) { LOG_DEBUG(packet4_logger, DBG_DHCP4_DETAIL, DHCP4_INFORM_DIRECT_REPLY) .arg(inform->getLabel()) .arg(ack->getRemoteAddr()) .arg(ack->getIface()); ack->setHops(0); ack->setGiaddr(IOAddress::IPV4_ZERO_ADDRESS()); ack->delOption(DHO_DHCP_AGENT_OPTIONS); } // The DHCPACK must contain server id. appendServerID(ex); /// @todo: decide whether we want to add a new hook point for /// doing class specific processing. if (!vendorClassSpecificProcessing(ex)) { LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, DHCP4_INFORM_CLASS_PROCESSING_FAILED) .arg(inform->getLabel()); } return (ex.getResponse()); } bool Dhcpv4Srv::accept(const Pkt4Ptr& query) const { // Check that the message type is accepted by the server. We rely on the // function called to log a message if needed. if (!acceptMessageType(query)) { return (false); } // Check if the message from directly connected client (if directly // connected) should be dropped or processed. if (!acceptDirectRequest(query)) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_0002) .arg(query->getLabel()) .arg(query->getIface()); return (false); } // Check if the DHCPv4 packet has been sent to us or to someone else. // If it hasn't been sent to us, drop it! if (!acceptServerId(query)) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_0003) .arg(query->getLabel()) .arg(query->getIface()); return (false); } return (true); } bool Dhcpv4Srv::acceptDirectRequest(const Pkt4Ptr& pkt) const { // Accept all relayed messages. if (pkt->isRelayed()) { return (true); } // Accept all DHCPv4-over-DHCPv6 messages. if (pkt->isDhcp4o6()) { return (true); } // The source address must not be zero for the DHCPINFORM message from // the directly connected client because the server will not know where // to respond if the ciaddr was not present. try { if (pkt->getType() == DHCPINFORM) { if (pkt->getRemoteAddr().isV4Zero() && pkt->getCiaddr().isV4Zero()) { return (false); } } } catch (...) { // If we got here, it is probably because the message type hasn't // been set. But, this should not really happen assuming that // we validate the message type prior to calling this function. return (false); } return (!pkt->getLocalAddr().isV4Bcast() || selectSubnet(pkt)); } bool Dhcpv4Srv::acceptMessageType(const Pkt4Ptr& query) const { // When receiving a packet without message type option, getType() will // throw. int type; try { type = query->getType(); } catch (...) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_0004) .arg(query->getLabel()) .arg(query->getIface()); return (false); } // If we receive a message with a non-existing type, we are logging it. if (type > DHCPLEASEQUERYDONE) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_0005) .arg(query->getLabel()) .arg(type); return (false); } // Once we know that the message type is within a range of defined DHCPv4 // messages, we do a detailed check to make sure that the received message // is targeted at server. Note that we could have received some Offer // message broadcasted by the other server to a relay. Even though, the // server would rather unicast its response to a relay, let's be on the // safe side. Also, we want to drop other messages which we don't support. // All these valid messages that we are not going to process are dropped // silently. if ((type != DHCPDISCOVER) && (type != DHCPREQUEST) && (type != DHCPRELEASE) && (type != DHCPDECLINE) && (type != DHCPINFORM)) { LOG_DEBUG(bad_packet4_logger, DBG_DHCP4_DETAIL, DHCP4_PACKET_DROP_0006) .arg(query->getLabel()) .arg(type); return (false); } return (true); } bool Dhcpv4Srv::acceptServerId(const Pkt4Ptr& query) const { // This function is meant to be called internally by the server class, so // we rely on the caller to sanity check the pointer and we don't check // it here. // Check if server identifier option is present. If it is not present // we accept the message because it is targeted to all servers. // Note that we don't check cases that server identifier is mandatory // but not present. This is meant to be sanity checked in other // functions. OptionPtr option = query->getOption(DHO_DHCP_SERVER_IDENTIFIER); if (!option) { return (true); } // Server identifier is present. Let's convert it to 4-byte address // and try to match with server identifiers used by the server. OptionCustomPtr option_custom = boost::dynamic_pointer_cast(option); // Unable to convert the option to the option type which encapsulates it. // We treat this as non-matching server id. if (!option_custom) { return (false); } // The server identifier option should carry exactly one IPv4 address. // If the option definition for the server identifier doesn't change, // the OptionCustom object should have exactly one IPv4 address and // this check is somewhat redundant. On the other hand, if someone // breaks option it may be better to check that here. if (option_custom->getDataFieldsNum() != 1) { return (false); } // The server identifier MUST be an IPv4 address. If given address is // v6, it is wrong. IOAddress server_id = option_custom->readAddress(); if (!server_id.isV4()) { return (false); } // This function iterates over all interfaces on which the // server is listening to find the one which has a socket bound // to the address carried in the server identifier option. // This has some performance implications. However, given that // typically there will be just a few active interfaces the // performance hit should be acceptable. If it turns out to // be significant, we will have to cache server identifiers // when sockets are opened. return (IfaceMgr::instance().hasOpenSocket(server_id)); } void Dhcpv4Srv::sanityCheck(const Pkt4Ptr& query, RequirementLevel serverid) { OptionPtr server_id = query->getOption(DHO_DHCP_SERVER_IDENTIFIER); switch (serverid) { case FORBIDDEN: if (server_id) { isc_throw(RFCViolation, "Server-id option was not expected, but " << "received in " << query->getName()); } break; case MANDATORY: if (!server_id) { isc_throw(RFCViolation, "Server-id option was expected, but not " " received in message " << query->getName()); } break; case OPTIONAL: // do nothing here ; } // If there is HWAddress set and it is non-empty, then we're good if (query->getHWAddr() && !query->getHWAddr()->hwaddr_.empty()) { return; } // There has to be something to uniquely identify the client: // either non-zero MAC address or client-id option present (or both) OptionPtr client_id = query->getOption(DHO_DHCP_CLIENT_IDENTIFIER); // If there's no client-id (or a useless one is provided, i.e. 0 length) if (!client_id || client_id->len() == client_id->getHeaderLen()) { isc_throw(RFCViolation, "Missing or useless client-id and no HW address " " provided in message " << query->getName()); } } void Dhcpv4Srv::classifyByVendor(const Pkt4Ptr& pkt, std::string& classes) { // Built-in vendor class processing boost::shared_ptr vendor_class = boost::dynamic_pointer_cast(pkt->getOption(DHO_VENDOR_CLASS_IDENTIFIER)); if (!vendor_class) { return; } // DOCSIS specific section // Let's keep this as a series of checks. So far we're supporting only // docsis3.0, but there are also docsis2.0, docsis1.1 and docsis1.0. We // may come up with adding several classes, e.g. for docsis2.0 we would // add classes docsis2.0, docsis1.1 and docsis1.0. // Also we are using find, because we have at least one traffic capture // where the user class was followed by a space ("docsis3.0 "). // For now, the code is very simple, but it is expected to get much more // complex soon. One specific case is that the vendor class is an option // sent by the client, so we should not trust it. To confirm that the device // is indeed a modem, John B. suggested to check whether chaddr field // quals subscriber-id option that was inserted by the relay (CMTS). // This kind of logic will appear here soon. if (vendor_class->getValue().find(DOCSIS3_CLASS_MODEM) != std::string::npos) { pkt->addClass(VENDOR_CLASS_PREFIX + DOCSIS3_CLASS_MODEM); classes += string(VENDOR_CLASS_PREFIX + DOCSIS3_CLASS_MODEM) + " "; } else if (vendor_class->getValue().find(DOCSIS3_CLASS_EROUTER) != std::string::npos) { pkt->addClass(VENDOR_CLASS_PREFIX + DOCSIS3_CLASS_EROUTER); classes += string(VENDOR_CLASS_PREFIX + DOCSIS3_CLASS_EROUTER) + " "; } else { pkt->addClass(VENDOR_CLASS_PREFIX + vendor_class->getValue()); classes += VENDOR_CLASS_PREFIX + vendor_class->getValue(); } } void Dhcpv4Srv::classifyPacket(const Pkt4Ptr& pkt) { string classes = ""; // First phase: built-in vendor class processing classifyByVendor(pkt, classes); // Run match expressions // Note getClientClassDictionary() cannot be null const ClientClassDefMapPtr& defs_ptr = CfgMgr::instance().getCurrentCfg()-> getClientClassDictionary()->getClasses(); for (ClientClassDefMap::const_iterator it = defs_ptr->begin(); it != defs_ptr->end(); ++it) { // Note second cannot be null const ExpressionPtr& expr_ptr = it->second->getMatchExpr(); // Nothing to do without an expression to evaluate if (!expr_ptr) { continue; } // Evaluate the expression which can return false (no match), // true (match) or raise an exception (error) try { bool status = evaluate(*expr_ptr, *pkt); if (status) { LOG_INFO(options4_logger, EVAL_RESULT) .arg(it->first) .arg(status); // Matching: add the class pkt->addClass(it->first); classes += it->first + " "; } else { LOG_DEBUG(options4_logger, DBG_DHCP4_DETAIL, EVAL_RESULT) .arg(it->first) .arg(status); } } catch (const Exception& ex) { LOG_ERROR(options4_logger, EVAL_RESULT) .arg(it->first) .arg(ex.what()); } catch (...) { LOG_ERROR(options4_logger, EVAL_RESULT) .arg(it->first) .arg("get exception?"); } } if (!classes.empty()) { LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_ASSIGNED) .arg(pkt->getLabel()) .arg(classes); } } bool Dhcpv4Srv::vendorClassSpecificProcessing(const Dhcpv4Exchange& ex) { Subnet4Ptr subnet = ex.getContext()->subnet_; Pkt4Ptr query = ex.getQuery(); Pkt4Ptr rsp = ex.getResponse(); // If any of those is missing, there is nothing to do. if (!subnet || !query || !rsp) { return (true); } if (query->inClass(VENDOR_CLASS_PREFIX + DOCSIS3_CLASS_MODEM)) { // Set next-server. This is TFTP server address. Cable modems will // download their configuration from that server. rsp->setSiaddr(subnet->getSiaddr()); // Now try to set up file field in DHCPv4 packet. We will just copy // content of the boot-file option, which contains the same information. const CfgOptionList& co_list = ex.getCfgOptionList(); for (CfgOptionList::const_iterator copts = co_list.begin(); copts != co_list.end(); ++copts) { OptionDescriptor desc = (*copts)->get("dhcp4", DHO_BOOT_FILE_NAME); if (desc.option_) { boost::shared_ptr boot = boost::dynamic_pointer_cast(desc.option_); if (boot) { std::string filename = boot->getValue(); rsp->setFile((const uint8_t*)filename.c_str(), filename.size()); break; } } } } if (query->inClass(VENDOR_CLASS_PREFIX + DOCSIS3_CLASS_EROUTER)) { // Do not set TFTP server address for eRouter devices. rsp->setSiaddr(IOAddress::IPV4_ZERO_ADDRESS()); } return (true); } void Dhcpv4Srv::startD2() { D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr(); if (d2_mgr.ddnsEnabled()) { // Updates are enabled, so lets start the sender, passing in // our error handler. // This may throw so wherever this is called needs to ready. d2_mgr.startSender(boost::bind(&Dhcpv4Srv::d2ClientErrorHandler, this, _1, _2)); } } void Dhcpv4Srv::stopD2() { D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr(); if (d2_mgr.ddnsEnabled()) { // Updates are enabled, so lets stop the sender d2_mgr.stopSender(); } } void Dhcpv4Srv::d2ClientErrorHandler(const dhcp_ddns::NameChangeSender::Result result, dhcp_ddns::NameChangeRequestPtr& ncr) { LOG_ERROR(ddns4_logger, DHCP4_DDNS_REQUEST_SEND_FAILED). arg(result).arg((ncr ? ncr->toText() : " NULL ")); // We cannot communicate with kea-dhcp-ddns, suspend further updates. /// @todo We may wish to revisit this, but for now we will simply turn /// them off. CfgMgr::instance().getD2ClientMgr().suspendUpdates(); } // Refer to config_report so it will be embedded in the binary const char* const* dhcp4_config_report = isc::detail::config_report; std::string Dhcpv4Srv::getVersion(bool extended) { std::stringstream tmp; tmp << VERSION; if (extended) { tmp << endl << EXTENDED_VERSION << endl; tmp << "linked with:" << endl; tmp << Logger::getVersion() << endl; tmp << CryptoLink::getVersion() << endl; tmp << "database:" << endl; #ifdef HAVE_MYSQL tmp << MySqlLeaseMgr::getDBVersion() << endl; #endif #ifdef HAVE_PGSQL tmp << PgSqlLeaseMgr::getDBVersion() << endl; #endif #ifdef HAVE_CQL tmp << CqlLeaseMgr::getDBVersion() << endl; #endif tmp << Memfile_LeaseMgr::getDBVersion(); // @todo: more details about database runtime } return (tmp.str()); } void Dhcpv4Srv::processStatsReceived(const Pkt4Ptr& query) { // Note that we're not bumping pkt4-received statistic as it was // increased early in the packet reception code. string stat_name = "pkt4-unknown-received"; try { switch (query->getType()) { case DHCPDISCOVER: stat_name = "pkt4-discover-received"; break; case DHCPOFFER: // Should not happen, but let's keep a counter for it stat_name = "pkt4-offer-received"; break; case DHCPREQUEST: stat_name = "pkt4-request-received"; break; case DHCPACK: // Should not happen, but let's keep a counter for it stat_name = "pkt4-ack-received"; break; case DHCPNAK: // Should not happen, but let's keep a counter for it stat_name = "pkt4-nak-received"; break; case DHCPRELEASE: stat_name = "pkt4-release-received"; break; case DHCPDECLINE: stat_name = "pkt4-decline-received"; break; case DHCPINFORM: stat_name = "pkt4-inform-received"; break; default: ; // do nothing } } catch (...) { // If the incoming packet doesn't have option 53 (message type) // or a hook set pkt4_receive_skip, then Pkt4::getType() may // throw an exception. That's ok, we'll then use the default // name of pkt4-unknown-received. } isc::stats::StatsMgr::instance().addValue(stat_name, static_cast(1)); } void Dhcpv4Srv::processStatsSent(const Pkt4Ptr& response) { // Increase generic counter for sent packets. isc::stats::StatsMgr::instance().addValue("pkt4-sent", static_cast(1)); // Increase packet type specific counter for packets sent. string stat_name; switch (response->getType()) { case DHCPOFFER: stat_name = "pkt4-offer-sent"; break; case DHCPACK: stat_name = "pkt4-ack-sent"; break; case DHCPNAK: stat_name = "pkt4-nak-sent"; break; default: // That should never happen return; } isc::stats::StatsMgr::instance().addValue(stat_name, static_cast(1)); } int Dhcpv4Srv::getHookIndexBuffer4Receive() { return (Hooks.hook_index_buffer4_receive_); } int Dhcpv4Srv::getHookIndexPkt4Receive() { return (Hooks.hook_index_pkt4_receive_); } int Dhcpv4Srv::getHookIndexSubnet4Select() { return (Hooks.hook_index_subnet4_select_); } int Dhcpv4Srv::getHookIndexLease4Release() { return (Hooks.hook_index_lease4_release_); } int Dhcpv4Srv::getHookIndexPkt4Send() { return (Hooks.hook_index_pkt4_send_); } int Dhcpv4Srv::getHookIndexBuffer4Send() { return (Hooks.hook_index_buffer4_send_); } int Dhcpv4Srv::getHookIndexLease4Decline() { return (Hooks.hook_index_lease4_decline_); } } // namespace dhcp } // namespace isc