[2994] lease4_select hook implemented.

src/lib/dhcpsrv/alloc_engine.cc

@@ -29,11 +29,13 @@ using namespace isc::hooks;
 namespace {
 
 /// Structure that holds registered hook indexes
-struct Dhcp6Hooks {
+struct AllocEngineHooks {
+    int hook_index_lease4_select_; ///< index for "lease4_receive" hook point
     int hook_index_lease6_select_; ///< index for "lease6_receive" hook point
 
     /// Constructor that registers hook points for AllocationEngine
-    Dhcp6Hooks() {
+    AllocEngineHooks() {
+        hook_index_lease6_select_ = HooksManager::registerHook("lease4_select");
         hook_index_lease6_select_ = HooksManager::registerHook("lease6_select");
     }
 };
@@ -42,7 +44,7 @@ struct Dhcp6Hooks {
 // 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.
-Dhcp6Hooks Hooks;
+AllocEngineHooks Hooks;
 
 }; // anonymous namespace
 
@@ -187,6 +189,7 @@ AllocEngine::AllocEngine(AllocType engine_type, unsigned int attempts)
     }
 
     // Register hook points
+    hook_index_lease4_select_ = Hooks.hook_index_lease4_select_;
     hook_index_lease6_select_ = Hooks.hook_index_lease6_select_;
 }
 
@@ -312,7 +315,8 @@ AllocEngine::allocateAddress4(const SubnetPtr& subnet,
                               const ClientIdPtr& clientid,
                               const HWAddrPtr& hwaddr,
                               const IOAddress& hint,
-                              bool fake_allocation /* = false */ ) {
+                              bool fake_allocation,
+                              const isc::hooks::CalloutHandlePtr& callout_handle) {
 
     try {
         // Allocator is always created in AllocEngine constructor and there is
@@ -365,7 +369,8 @@ AllocEngine::allocateAddress4(const SubnetPtr& subnet,
                 /// implemented
 
                 // The hint is valid and not currently used, let's create a lease for it
-                Lease4Ptr lease = createLease4(subnet, clientid, hwaddr, hint, fake_allocation);
+                Lease4Ptr lease = createLease4(subnet, clientid, hwaddr, hint,
+                                               callout_handle, fake_allocation);
 
                 // It can happen that the lease allocation failed (we could have lost
                 // the race condition. That means that the hint is lo longer usable and
@@ -376,7 +381,7 @@ AllocEngine::allocateAddress4(const SubnetPtr& subnet,
             } else {
                 if (existing->expired()) {
                     return (reuseExpiredLease(existing, subnet, clientid, hwaddr,
-                                              fake_allocation));
+                                              callout_handle, fake_allocation));
                 }
 
             }
@@ -410,7 +415,7 @@ AllocEngine::allocateAddress4(const SubnetPtr& subnet,
                 // there's no existing lease for selected candidate, so it is
                 // free. Let's allocate it.
                 Lease4Ptr lease = createLease4(subnet, clientid, hwaddr, candidate,
-                                              fake_allocation);
+                                               callout_handle, fake_allocation);
                 if (lease) {
                     return (lease);
                 }
@@ -421,7 +426,7 @@ AllocEngine::allocateAddress4(const SubnetPtr& subnet,
             } else {
                 if (existing->expired()) {
                     return (reuseExpiredLease(existing, subnet, clientid, hwaddr,
-                                              fake_allocation));
+                                              callout_handle, fake_allocation));
                 }
             }
 
@@ -515,7 +520,7 @@ Lease6Ptr AllocEngine::reuseExpiredLease(Lease6Ptr& expired,
         // assigned, so the client will get NoAddrAvail as a result. The lease
         // won't be inserted into the
         if (callout_handle->getSkip()) {
-            LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_HOOKS, DHCPSRV_HOOK_LEASE6_IA_ADD_SKIP);
+            LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_HOOKS, DHCPSRV_HOOK_LEASE6_SELECT_SKIP);
             return (Lease6Ptr());
         }
 
@@ -541,6 +546,7 @@ Lease4Ptr AllocEngine::reuseExpiredLease(Lease4Ptr& expired,
                                          const SubnetPtr& subnet,
                                          const ClientIdPtr& clientid,
                                          const HWAddrPtr& hwaddr,
+                                         const isc::hooks::CalloutHandlePtr& callout_handle,
                                          bool fake_allocation /*= false */ ) {
 
     if (!expired->expired()) {
@@ -563,6 +569,39 @@ Lease4Ptr AllocEngine::reuseExpiredLease(Lease4Ptr& expired,
     /// @todo: log here that the lease was reused (there's ticket #2524 for
     /// logging in libdhcpsrv)
 
+    // Let's execute all callouts registered for lease4_select
+    if (callout_handle &&
+        HooksManager::getHooksManager().calloutsPresent(hook_index_lease4_select_)) {
+
+        // Delete all previous arguments
+        callout_handle->deleteAllArguments();
+
+        // Pass necessary arguments
+        // Subnet from which we do the allocation
+        callout_handle->setArgument("subnet4", subnet);
+
+        // Is this solicit (fake = true) or request (fake = false)
+        callout_handle->setArgument("fake_allocation", fake_allocation);
+
+        // The lease that will be assigned to a client
+        callout_handle->setArgument("lease4", expired);
+
+        // Call the callouts
+        HooksManager::callCallouts(hook_index_lease6_select_, *callout_handle);
+
+        // Callouts decided to skip the action. This means that the lease is not
+        // assigned, so the client will get NoAddrAvail as a result. The lease
+        // won't be inserted into the
+        if (callout_handle->getSkip()) {
+            LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_HOOKS, DHCPSRV_HOOK_LEASE4_SELECT_SKIP);
+            return (Lease4Ptr());
+        }
+
+        // Let's use whatever callout returned. Hopefully it is the same lease
+        // we handled to it.
+        callout_handle->getArgument("lease4", expired);
+    }
+
     if (!fake_allocation) {
         // for REQUEST we do update the lease
         LeaseMgrFactory::instance().updateLease4(expired);
@@ -587,7 +626,7 @@ Lease6Ptr AllocEngine::createLease6(const Subnet6Ptr& subnet,
                                subnet->getPreferred(), subnet->getValid(),
                                subnet->getT1(), subnet->getT2(), subnet->getID()));
 
-    // Let's execute all callouts registered for lease6_ia_added
+    // Let's execute all callouts registered for lease6_select
     if (callout_handle &&
         HooksManager::getHooksManager().calloutsPresent(hook_index_lease6_select_)) {
 
@@ -613,7 +652,7 @@ Lease6Ptr AllocEngine::createLease6(const Subnet6Ptr& subnet,
         // assigned, so the client will get NoAddrAvail as a result. The lease
         // won't be inserted into the
         if (callout_handle->getSkip()) {
-            LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_HOOKS, DHCPSRV_HOOK_LEASE6_IA_ADD_SKIP);
+            LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_HOOKS, DHCPSRV_HOOK_LEASE6_SELECT_SKIP);
             return (Lease6Ptr());
         }
 
@@ -654,6 +693,7 @@ Lease4Ptr AllocEngine::createLease4(const SubnetPtr& subnet,
                                     const DuidPtr& clientid,
                                     const HWAddrPtr& hwaddr,
                                     const IOAddress& addr,
+                                    const isc::hooks::CalloutHandlePtr& callout_handle,
                                     bool fake_allocation /*= false */ ) {
     if (!hwaddr) {
         isc_throw(BadValue, "Can't create a lease with NULL HW address");
@@ -671,6 +711,43 @@ Lease4Ptr AllocEngine::createLease4(const SubnetPtr& subnet,
                                subnet->getT1(), subnet->getT2(), now,
                                subnet->getID()));
 
+    // Let's execute all callouts registered for lease4_select
+    if (callout_handle &&
+        HooksManager::getHooksManager().calloutsPresent(hook_index_lease4_select_)) {
+
+        // Delete all previous arguments
+        callout_handle->deleteAllArguments();
+
+        // Clear skip flag if it was set in previous callouts
+        callout_handle->setSkip(false);
+
+        // Pass necessary arguments
+
+        // Subnet from which we do the allocation
+        callout_handle->setArgument("subnet4", subnet);
+
+        // Is this solicit (fake = true) or request (fake = false)
+        callout_handle->setArgument("fake_allocation", fake_allocation);
+        callout_handle->setArgument("lease4", lease);
+
+        // This is the first callout, so no need to clear any arguments
+        HooksManager::callCallouts(hook_index_lease4_select_, *callout_handle);
+
+        // Callouts decided to skip the action. This means that the lease is not
+        // assigned, so the client will get NoAddrAvail as a result. The lease
+        // won't be inserted into the
+        if (callout_handle->getSkip()) {
+            LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_HOOKS, DHCPSRV_HOOK_LEASE4_SELECT_SKIP);
+            return (Lease4Ptr());
+        }
+
+        // Let's use whatever callout returned. Hopefully it is the same lease
+        // we handled to it.
+        callout_handle->getArgument("lease6", lease);
+    }
+
+
+
     if (!fake_allocation) {
         // That is a real (REQUEST) allocation
         bool status = LeaseMgrFactory::instance().addLease(lease);

src/lib/dhcpsrv/alloc_engine.h

@@ -194,13 +194,16 @@ protected:
     /// @param hint a hint that the client provided
     /// @param fake_allocation is this real i.e. REQUEST (false) or just picking
     ///        an address for DISCOVER that is not really allocated (true)
+    /// @param callout_handle a callout handle (used in hooks). A lease callouts
+    ///        will be executed if this parameter is passed.
     /// @return Allocated IPv4 lease (or NULL if allocation failed)
     Lease4Ptr
     allocateAddress4(const SubnetPtr& subnet,
                      const ClientIdPtr& clientid,
                      const HWAddrPtr& hwaddr,
                      const isc::asiolink::IOAddress& hint,
-                     bool fake_allocation);
+                     bool fake_allocation,
+                     const isc::hooks::CalloutHandlePtr& callout_handle);
 
     /// @brief Renews a IPv4 lease
     ///
@@ -262,6 +265,8 @@ private:
     /// @param clientid client identifier
     /// @param hwaddr client's hardware address
     /// @param addr an address that was selected and is confirmed to be available
+    /// @param callout_handle a callout handle (used in hooks). A lease callouts
+    ///        will be executed if this parameter is passed.
     /// @param fake_allocation is this real i.e. REQUEST (false) or just picking
     ///        an address for DISCOVER that is not really allocated (true)
     /// @return allocated lease (or NULL in the unlikely case of the lease just
@@ -269,6 +274,7 @@ private:
     Lease4Ptr createLease4(const SubnetPtr& subnet, const DuidPtr& clientid,
                            const HWAddrPtr& hwaddr,
                            const isc::asiolink::IOAddress& addr,
+                           const isc::hooks::CalloutHandlePtr& callout_handle,
                            bool fake_allocation = false);
 
     /// @brief creates a lease and inserts it in LeaseMgr if necessary
@@ -302,6 +308,8 @@ private:
     /// @param subnet subnet the lease is allocated from
     /// @param clientid client identifier
     /// @param hwaddr client's hardware address
+    /// @param callout_handle a callout handle (used in hooks). A lease callouts
+    ///        will be executed if this parameter is passed.
     /// @param fake_allocation is this real i.e. REQUEST (false) or just picking
     ///        an address for DISCOVER that is not really allocated (true)
     /// @return refreshed lease
@@ -309,6 +317,7 @@ private:
     Lease4Ptr reuseExpiredLease(Lease4Ptr& expired, const SubnetPtr& subnet,
                                 const ClientIdPtr& clientid,
                                 const HWAddrPtr& hwaddr,
+                                const isc::hooks::CalloutHandlePtr& callout_handle,
                                 bool fake_allocation = false);
 
     /// @brief Reuses expired IPv6 lease
@@ -338,8 +347,9 @@ private:
     /// @brief number of attempts before we give up lease allocation (0=unlimited)
     unsigned int attempts_;
 
-    /// @brief hook name index (used in hooks callouts)
-    int hook_index_lease6_select_;
+    // hook name indexes (used in hooks callouts)
+    int hook_index_lease4_select_; ///< index for lease4_select hook
+    int hook_index_lease6_select_; ///< index for lease6_select hook
 };
 
 }; // namespace isc::dhcp

src/lib/dhcpsrv/dhcpsrv_messages.mes

@@ -121,8 +121,14 @@ the database access parameters are changed: in the latter case, the
 server closes the currently open database, and opens a database using
 the new parameters.
 
-% DHCPSRV_HOOK_LEASE6_IA_ADD_SKIP Lease6 (non-temporary) creation was skipped, because of callout skip flag.
-This debug message is printed when a callout installed on lease6_assign
+% DHCPSRV_HOOK_LEASE4_SELECT_SKIP Lease4 creation was skipped, because of callout skip flag.
+This debug message is printed when a callout installed on lease4_select
+hook point sets a skip flag. It means that the server was told that no lease4
+should be assigned. The server will not put that lease in its database and the client
+will get a NAK packet.
+
+% DHCPSRV_HOOK_LEASE6_SELECT_SKIP Lease6 (non-temporary) creation was skipped, because of callout skip flag.
+This debug message is printed when a callout installed on lease6_select
 hook point sets a skip flag. It means that the server was told that no lease6
 should be assigned. The server will not put that lease in its database and the client
 will get a NoAddrsAvail for that IA_NA option.

src/lib/dhcpsrv/tests/alloc_engine_unittest.cc

@@ -592,7 +592,8 @@ TEST_F(AllocEngine4Test, simpleAlloc4) {
     ASSERT_TRUE(engine);
 
     Lease4Ptr lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
-                                               IOAddress("0.0.0.0"), false);
+                                               IOAddress("0.0.0.0"), false,
+                                               CalloutHandlePtr());
 
     // Check that we got a lease
     ASSERT_TRUE(lease);
@@ -615,7 +616,8 @@ TEST_F(AllocEngine4Test, fakeAlloc4) {
     ASSERT_TRUE(engine);
 
     Lease4Ptr lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
-                                               IOAddress("0.0.0.0"), true);
+                                               IOAddress("0.0.0.0"), true,
+                                               CalloutHandlePtr());
 
     // Check that we got a lease
     ASSERT_TRUE(lease);
@@ -638,7 +640,7 @@ TEST_F(AllocEngine4Test, allocWithValidHint4) {
 
     Lease4Ptr lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
                                                IOAddress("192.0.2.105"),
-                                               false);
+                                               false, CalloutHandlePtr());
 
     // Check that we got a lease
     ASSERT_TRUE(lease);
@@ -678,7 +680,7 @@ TEST_F(AllocEngine4Test, allocWithUsedHint4) {
     // twice.
     Lease4Ptr lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
                                                IOAddress("192.0.2.106"),
-                                               false);
+                                               false, CalloutHandlePtr());
     // Check that we got a lease
     ASSERT_TRUE(lease);
 
@@ -712,7 +714,7 @@ TEST_F(AllocEngine4Test, allocBogusHint4) {
     // with the normal allocation
     Lease4Ptr lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
                                                IOAddress("10.1.1.1"),
-                                               false);
+                                               false, CalloutHandlePtr());
     // Check that we got a lease
     ASSERT_TRUE(lease);
 
@@ -739,18 +741,19 @@ TEST_F(AllocEngine4Test, allocateAddress4Nulls) {
 
     // Allocations without subnet are not allowed
     Lease4Ptr lease = engine->allocateAddress4(SubnetPtr(), clientid_, hwaddr_,
-                                               IOAddress("0.0.0.0"), false);
+                                               IOAddress("0.0.0.0"), false,
+                                               CalloutHandlePtr());
     EXPECT_FALSE(lease);
 
     // Allocations without HW address are not allowed
     lease = engine->allocateAddress4(subnet_, clientid_, HWAddrPtr(),
-                                     IOAddress("0.0.0.0"), false);
+                                     IOAddress("0.0.0.0"), false, CalloutHandlePtr());
     EXPECT_FALSE(lease);
 
     // Allocations without client-id are allowed
     clientid_ = ClientIdPtr();
     lease = engine->allocateAddress4(subnet_, ClientIdPtr(), hwaddr_,
-                                     IOAddress("0.0.0.0"), false);
+                                     IOAddress("0.0.0.0"), false, CalloutHandlePtr());
     // Check that we got a lease
     ASSERT_TRUE(lease);
 
@@ -854,7 +857,7 @@ TEST_F(AllocEngine4Test, smallPool4) {
     cfg_mgr.addSubnet4(subnet_);
 
     Lease4Ptr lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_, IOAddress("0.0.0.0"),
-                                               false);
+                                               false, CalloutHandlePtr());
 
     // Check that we got that single lease
     ASSERT_TRUE(lease);
@@ -902,7 +905,8 @@ TEST_F(AllocEngine4Test, outOfAddresses4) {
     // else, so the allocation should fail
 
     Lease4Ptr lease2 = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
-                                                IOAddress("0.0.0.0"), false);
+                                                IOAddress("0.0.0.0"), false,
+                                                CalloutHandlePtr());
     EXPECT_FALSE(lease2);
 }
 
@@ -935,7 +939,7 @@ TEST_F(AllocEngine4Test, discoverReuseExpiredLease4) {
 
     // CASE 1: Asking for any address
     lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_, IOAddress("0.0.0.0"),
-                                     true);
+                                     true, CalloutHandlePtr());
     // Check that we got that single lease
     ASSERT_TRUE(lease);
     EXPECT_EQ(addr.toText(), lease->addr_.toText());
@@ -945,7 +949,7 @@ TEST_F(AllocEngine4Test, discoverReuseExpiredLease4) {
 
     // CASE 2: Asking specifically for this address
     lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_, IOAddress(addr.toText()),
-                                     true);
+                                     true, CalloutHandlePtr());
     // Check that we got that single lease
     ASSERT_TRUE(lease);
     EXPECT_EQ(addr.toText(), lease->addr_.toText());
@@ -972,7 +976,8 @@ TEST_F(AllocEngine4Test, requestReuseExpiredLease4) {
 
     // A client comes along, asking specifically for this address
     lease = engine->allocateAddress4(subnet_, clientid_, hwaddr_,
-                                     IOAddress(addr.toText()), false);
+                                     IOAddress(addr.toText()), false,
+                                     CalloutHandlePtr());
 
     // Check that he got that single lease
     ASSERT_TRUE(lease);