[5306] Updated DHCPv4 server to use shared networks.

src/bin/dhcp4/dhcp4_messages.mes

@@ -320,14 +320,6 @@ be sent to the client in the DHCPACK message. The first argument contains the
 client and the transaction identification information. The second argument
 contains the allocated IPv4 address.
 
-% DHCP4_NAME_GEN_UPDATE_FAIL %1: failed to update the lease after generating name %2 for a client: %3
-This message indicates the failure when trying to update the lease and/or
-options in the server's response with the hostname generated by the server
-from the acquired IPv4 address. The message argument indicates the reason
-for the failure. The first argument includes the client and the transaction
-identification information. The second argument specifies the hostname.
-The third argument contains the error details.
-
 % DHCP4_NCR_CREATE %1: DDNS updates enabled, therefore sending name change requests
 This debug message is issued when the server is starting to send
 name change requests to the D2 module to update records for the client
@@ -531,6 +523,13 @@ of the named configuration element, or the creation succeeded but the
 parsing actions and committal of changes failed.  The reason for the
 failure is given in the message.
 
+% DHCP4_POST_ALLOCATION_NAME_UPDATE_FAIL %1: failed to update hostname %2 in a lease after address allocation: %3
+This message indicates the failure when trying to update the lease and/or
+options in the server's response with the hostname generated by the server
+or reserved for the client belonging to a shared network. The latter is
+the case when the server dynamically switches to another subnet (than
+initially selected for allocation) from the same shared network.
+
 % DHCP4_QUERY_DATA %1, packet details: %2
 A debug message printing the details of the received packet. The first
 argument includes the client and the transaction identification

src/bin/dhcp4/dhcp4_srv.cc

@@ -29,6 +29,7 @@
 #include <dhcpsrv/lease_mgr.h>
 #include <dhcpsrv/lease_mgr_factory.h>
 #include <dhcpsrv/ncr_generator.h>
+#include <dhcpsrv/shared_network.h>
 #include <dhcpsrv/subnet.h>
 #include <dhcpsrv/subnet_selector.h>
 #include <dhcpsrv/utils.h>
@@ -155,9 +156,6 @@ Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
 
             // Check for static reservations.
             alloc_engine->findReservation(*context_);
-
-            // Assign classes.
-            setReservedClientClasses();
         }
     }
 
@@ -1177,6 +1175,13 @@ Dhcpv4Srv::buildCfgOptionList(Dhcpv4Exchange& ex) {
         co_list.push_back(subnet->getCfgOption());
     }
 
+    // Thirdly, shared network specific options.
+    SharedNetwork4Ptr network;
+    subnet->getSharedNetwork(network);
+    if (network && !network->getCfgOption()->empty()) {
+        co_list.push_back(network->getCfgOption());
+    }
+
     // Each class in the incoming packet
     const ClientClasses& classes = ex.getQuery()->getClasses();
     for (ClientClasses::const_iterator cclass = classes.begin();
@@ -1741,12 +1746,23 @@ Dhcpv4Srv::assignLease(Dhcpv4Exchange& ex) {
             .arg(hint.toText());
 
         Lease4Ptr lease;
-        if (client_id) {
-            lease = LeaseMgrFactory::instance().getLease4(*client_id, subnet->getID());
-        }
+        Subnet4Ptr original_subnet = subnet;
+        Subnet4Ptr s = original_subnet;
+        while (s) {
+            if (client_id) {
+                lease = LeaseMgrFactory::instance().getLease4(*client_id, s->getID());
+            }
+
+            if (!lease && hwaddr) {
+                lease = LeaseMgrFactory::instance().getLease4(*hwaddr, s->getID());
+            }
 
-        if (!lease && hwaddr) {
-            lease = LeaseMgrFactory::instance().getLease4(*hwaddr, subnet->getID());
+            if (lease ) {
+                break;
+
+            } else {
+                s = s->getNextSubnet(original_subnet, query->getClasses());
+            }
         }
 
         // Check the first error case: unknown client. We check this before
@@ -1820,6 +1836,10 @@ Dhcpv4Srv::assignLease(Dhcpv4Exchange& ex) {
 
     Lease4Ptr lease = alloc_engine_->allocateLease4(*ctx);
 
+    // Subnet may be modified by the allocation engine, if the initial subnet
+    // belongs to a shared network.
+    subnet = ctx->subnet_;
+
     if (lease) {
         // We have a lease! Let's set it in the packet and send it back to
         // the client.
@@ -1841,49 +1861,71 @@ Dhcpv4Srv::assignLease(Dhcpv4Exchange& ex) {
             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<bool>(fqdn));
-
-            LOG_DEBUG(ddns4_logger, DBG_DHCP4_DETAIL, DHCP4_RESPONSE_HOSTNAME_GENERATE)
-                .arg(query->getLabel())
-                .arg(lease->hostname_);
+        // We may need to update FQDN or hostname if the server is to generate
+        // new name from the allocated IP address or if the allocation engine
+        // has switched to a different subnet (from the same shared network)
+        // where the client has hostname reservations.
+        if (fqdn || opt_hostname) {
+            bool should_update = false;
+
+            // If there is a reservation in the current subnet for a hostname,
+            // we need to use this reserved name.
+            if (ctx->currentHost() && !ctx->currentHost()->getHostname().empty()) {
+
+                lease->hostname_ = CfgMgr::instance().getD2ClientMgr()
+                    .qualifyName(ctx->currentHost()->getHostname(),
+                                 static_cast<bool>(fqdn));
+                should_update = true;
+
+            // 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.
+            } else if (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<bool>(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);
-                }
+                should_update = true;
+            }
 
-                // 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_);
-                }
+            if (should_update) {
+
+                // 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);
+                    }
 
-            } catch (const Exception& ex) {
-                LOG_ERROR(ddns4_logger, DHCP4_NAME_GEN_UPDATE_FAIL)
-                    .arg(query->getLabel())
-                    .arg(lease->hostname_)
-                    .arg(ex.what());
+                    // 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_POST_ALLOCATION_NAME_UPDATE_FAIL)
+                        .arg(query->getLabel())
+                        .arg(lease->hostname_)
+                        .arg(ex.what());
+                }
             }
         }
 
@@ -2204,6 +2246,9 @@ Dhcpv4Srv::processDiscover(Pkt4Ptr& discover) {
         return (Pkt4Ptr());
     }
 
+    // Assign reserved classes.
+    ex.setReservedClientClasses();
+
     // Adding any other options makes sense only when we got the lease.
     if (!ex.getResponse()->getYiaddr().isV4Zero()) {
         buildCfgOptionList(ex);
@@ -2256,6 +2301,9 @@ Dhcpv4Srv::processRequest(Pkt4Ptr& request) {
         return (Pkt4Ptr());
     }
 
+    // Assign reserved classes.
+    ex.setReservedClientClasses();
+
     // Adding any other options makes sense only when we got the lease.
     if (!ex.getResponse()->getYiaddr().isV4Zero()) {
         buildCfgOptionList(ex);
@@ -2540,6 +2588,8 @@ Dhcpv4Srv::processInform(Pkt4Ptr& inform) {
 
     Pkt4Ptr ack = ex.getResponse();
 
+    ex.setReservedClientClasses();
+
     buildCfgOptionList(ex);
     appendRequestedOptions(ex);
     appendRequestedVendorOptions(ex);

src/bin/dhcp4/dhcp4_srv.h

@@ -123,6 +123,9 @@ public:
     /// server's response.
     void setReservedMessageFields();
 
+    /// @brief Assigns classes retrieved from host reservation database.
+    void setReservedClientClasses();
+
 private:
 
     /// @brief Copies default parameters from client's to server's message
@@ -155,9 +158,6 @@ private:
     /// host-reservation-identifiers
     void setHostIdentifiers();
 
-    /// @brief Assigns classes retrieved from host reservation database.
-    void setReservedClientClasses();
-
     /// @brief Pointer to the allocation engine used by the server.
     AllocEnginePtr alloc_engine_;
     /// @brief Pointer to the DHCPv4 message sent by the client.