[5017] Examples for echo-client-id and match-client-id added.

doc/examples/kea4/hooks.json

@@ -37,7 +37,11 @@
         "library": "/opt/lib/security.so"
      },
      {
-        "library": "/opt/lib/charging.so"
+         "library": "/opt/lib/charging.so",
+         "parameters": {
+             "path": "/var/kea/var",
+             "base-name": "kea-forensic6"
+         }
      }
   ]
 }

doc/examples/kea4/several-subnets.json

@@ -27,15 +27,36 @@
   "renew-timer": 1000,
   "rebind-timer": 2000,
 
+# RFC6842 says that the server is supposed to echo back client-id option.
+# However, some older clients do not support this and are getting confused
+# when they get their own client-id. Kea can disable RFC6842 support.
+  "echo-client-id": false,
+
+# Some clients don't use stable client identifier, but rather generate them
+# during each boot. This may cause a client that reboots frequently to get
+# multiple leases, which may not be desirable. As such, sometimes admins
+# prefer to tell their DHCPv4 server to ignore client-id value altogether
+# and rely exclusively on MAC address. This is a parameter that is defined
+# globally, but can be overridden on a subnet level.
+  "match-client-id": true,
+
 # The following list defines subnets. Each subnet consists of at
 # least subnet and pool entries.
-  "subnet4": [ 
-  {    "pools": [ { "pool":  "192.0.2.1 - 192.0.2.200" } ],
-       "subnet": "192.0.2.0/24"  },
-  {    "pools": [ { "pool": "192.0.3.100 - 192.0.3.200" } ],
-       "subnet": "192.0.3.0/24"  },
-  {    "pools": [ { "pool": "192.0.4.1 - 192.0.4.254" } ],
-       "subnet": "192.0.4.0/24"  } ]
+  "subnet4": [
+  {
+      "pools": [ { "pool":  "192.0.2.1 - 192.0.2.200" } ],
+      "subnet": "192.0.2.0/24"
+  },
+  {
+# This particular subnet has match-client-id value changed.
+      "pools": [ { "pool": "192.0.3.100 - 192.0.3.200" } ],
+      "subnet": "192.0.3.0/24",
+      "match-client-id": false
+  },
+  {
+      "pools": [ { "pool": "192.0.4.1 - 192.0.4.254" } ],
+      "subnet": "192.0.4.0/24"
+  } ]
 },
 
 # The following configures logging. It assumes that messages with at least

src/bin/dhcp4/.gitignore

@@ -5,3 +5,4 @@
 /spec_config.h
 /spec_config.h.pre
 /s-messages
+/dhcp4_parser.report

src/bin/dhcp4/dhcp4_lexer.ll

@@ -862,6 +862,7 @@ ControlCharacterFill            [^"\\]|\\{JSONEscapeSequence}
 
 \"echo-client-id\" {
     switch(driver.ctx_) {
+    case isc::dhcp::Parser4Context::DHCP4:
     case isc::dhcp::Parser4Context::SUBNET4:
         return isc::dhcp::Dhcp4Parser::make_ECHO_CLIENT_ID(driver.loc_);
     default:
@@ -871,6 +872,7 @@ ControlCharacterFill            [^"\\]|\\{JSONEscapeSequence}
 
 \"match-client-id\" {
     switch(driver.ctx_) {
+    case isc::dhcp::Parser4Context::DHCP4:
     case isc::dhcp::Parser4Context::SUBNET4:
         return isc::dhcp::Dhcp4Parser::make_MATCH_CLIENT_ID(driver.loc_);
     default: