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| Table of Contents | ||
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Introduction
SNMP Protocol Agent (PA) provides the solution for SNMP Protocol to access CCSP Data Model.
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This is the architecture diagram of SNMP Protocol Agent
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| draw.io Diagram | ||||
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CCSP SNMP Protocol Agent is implemented as a NET-SNMP MIB handler. During startup, it loads all the XML files defining the following:
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The callback prototype is:
| Code Block |
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typedef int (*handleRequestsProc) |
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( |
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netsnmp_mib_handler *handler, |
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netsnmp_handler_registration *reginfo, |
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netsnmp_agent_request_info *reqinfo, |
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netsnmp_request_info *requests |
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); |
This callback will be called before SNMP Protocol Agent MIB handler processing the requests. If the callback takes care of certain request and it doesn’t want to be processed anymore, the “requests->processed” should be set to 1. In this case, the MIB handler will ignore this request and move on.
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<!-‐-‐ Definition of callbackInfo -‐-‐>
| Code Block |
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<xs:complexType name="callbackInfo"> |
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<xs:sequence> |
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<!-‐-‐ The prototype of the “handleRequests”: |
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typedef int |
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(*handleRequestsProc) |
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( |
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netsnmp_mib_handler *handler, |
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netsnmp_handler_registration *reginfo, |
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netsnmp_agent_request_info *reqinfo, |
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netsnmp_request_info *requests |
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); |
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This callback will be called before Ccsp generic MIB handler. |
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Whenever a request was handled in this callback, you may set “request-‐>processed” to 1. |
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-‐-‐> |
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<xs:element name="handleRequests" type="xs:string" minOccurs=”0” /> |
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<!-‐-‐ The prototype of the “refreshCache”: |
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typedef int |
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(*refreshCacheProc) |
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( |
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netsnmp_tdata* table |
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); |
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This callback will be called first in RefreshCache of Ccsp generic MIB handler. |
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-‐-‐> |
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<xs:element name="refreshCache" type="xs:string" minOccurs=”0” /> |
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</xs:sequence> |
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</xs:complexType> |
Node of “mapping”
Mapping is consisted of two parts,
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<!-‐-‐ Definition of mibInfo -‐-‐>
| Code Block |
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<xs:complexType name="mibInfo"> <xs:sequence> <xs:element name="lastOid" type="xs:positiveInteger" /> |
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<!-- The “name” will not be used by SNMP agent, but it will be helpful when editing the mapping file. It’s optional. -‐-‐> |
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<xs:element name="name" type="xs:string" minOccurs=”0” /> <xs:element name="access" type="mibAccess" /> |
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<!— The data type of this mib -‐-‐> |
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<xs:element name="dataType" type="xs:string" /> <xs:element name="range" type="rangeInfo" minOccurs=”0”/> </xs:sequence> </xs:complexType> |
<!-‐-‐ Definition of dmInfo -‐-‐>
| Code Block |
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<xs:complexType name="dmInfo"> <xs:sequence> |
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<!-- It defines the mapped Data Model parameter name. It could be under an object or a table. -‐-‐> |
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<!-- For instance, “Device.DeviceInfo.SoftwareVersion” or “Device.Hosts.Host.%d.Name”. -‐-‐> |
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<xs:element name="paramName" type="xs:string" /> <xs:element name="dataType" type="trDataType " /> |
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<!-- Enumeration is an integer in MIB while a string value in TR data model. We put one single string including the whole mapping. -‐-‐ > |
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<!-- For instance “None(0), Requested(1), Complete(2), Error(3)”. The maps are separated by a ‘,’.-‐-‐> |
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<!-‐-‐ The bitmask type is also supported. It’s a choice of data type extension here -‐-‐> |
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<xs:choice minOccurs=”0”> <xs:element name="enumeration" type="xs:string" /> <xs:element name="bitmask" type="xs:string" /> </xs:choice> </xs:sequence> </xs:complexType> |
<!-‐-‐ Definition of mappingInfo -‐-‐>
| Code Block |
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<xs:complexType name="mappingInfo"> <xs:sequence> <xs:element name="mib" type="mibInfo" /> |
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<!—Certain mibs may not need a mapping in DM, such as “StorageType”. Hence it’s optional. -‐-‐> |
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<xs:element name="dm" type="dmInfo" minOccurs=”0” /> </xs:sequence> </xs:complexType> |
Node of “scalarGroup”
This node defines how scalar MIB objects are mapped to Data Model objects:
<!---- Definition of a scalarGroupInfo -‐-‐>
| Code Block |
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<xs:complexType name="scalarGroupInfo"> <xs:sequence> |
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<!-‐-‐ Unique name of group name. It could be the name of baseOid. It will be used for the hook/callback registration. -‐-‐> |
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<xs:element name="name" type="xs:string"/> |
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<!-‐-‐ “baseOid” is the base OID string for this group of scalar mibs. All the mibs have to be in the same OID layer. -‐-‐> |
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<!-‐-‐ Otherwise, put them in another scalarGroup. -‐-‐> |
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<xs:element name="baseOid" type="xs:string"/> |
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<!-‐-‐ “enabled” is defined in case this group is not ready at back-‐end yet or deprecated -‐-‐ > |
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<!-‐-‐ If it’s not enabled, the MIB handler will not load it. It’s enabled if the node doesn’t present (by default) -‐-‐> |
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<xs:element name="enabled" type="xs:boolean" minOccurs="0"/> |
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<!-‐-‐ Cache is always recommended for performance concerns. The default is 30 seconds -‐-‐> |
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<xs:element name="cacheTimeout" type="xs:nonNegativeInteger" minOccurs="0" /> |
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<!-‐-‐ In some special case, the scalar mibs may map to an entry in Data Model Table. -‐-‐> |
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<!-‐-‐ This optional node provides conditional mapping. For instance, “Wifi.Radio.%d.Frequency=2.4” -‐-‐> |
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<xs:element name="mapToEntry" type="xs:string" minOccurs="0" /> |
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<!-‐-‐ If callback/hook functions are needed for this group, add it here. -‐-‐> |
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<xs:element name="callbacks" type="callbackInfo " minOccurs="0" /> |
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<!-‐-‐ a set of mibs -‐-‐> |
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<xs:element name="mapping" type="mappingInfo" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> |
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Node of “mibTable” |
Because table objects covers more than parameters, more work and functionalities are included:
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<!-‐-‐ Definition of indexInfo -‐-‐>
| Code Block |
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<xs:complexType name="indexInfo"> <xs:sequence> <xs:element name="mib" type="mibInfo" /> <xs:choice> |
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<!-- The mib may be mapped to the instance number of data model entry. It’s false by default. -‐-‐> |
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<xs:element name="mapToInsNumber" type="type:mapToInsInfo" /> |
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<!-- If it’s not mapped to instance number, it will be mapped to a data model parameter. -‐-‐> |
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<xs:element name="dm" type="dmInfo" /> </xs:choice> </xs:sequence> </xs:complexType> |
<!-‐-‐ Definition of a mibTableInfo -‐-‐>
| Code Block |
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<xs:complexType name="mibTableInfo"> <xs:sequence> |
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<!-‐-‐ Mib table name. It will be used for the hook/callback registration. -‐-‐> |
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<xs:element name="name" type="xs:string"/> |
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<!-‐-‐ The fully OID of the mib table (not entry). For instance “1,3,6,1,4,8072,2,2,2“.-‐-‐> |
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<!-‐-‐ Otherwise, put them in another scalarGroup. -‐-‐> |
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<xs:element name="tableOid" type="xs:string"/> |
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<!-‐-‐ “enabled” is defined in case this group is not ready at back-‐end yet or deprecated -‐-‐ > |
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<!-‐-‐ If it’s not enabled, the MIB handler will not load it. It’s enabled if the node doesn’t present (by default) -‐-‐> |
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<xs:element name="enabled" type="xs:boolean" minOccurs="0"/> |
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<!-‐-‐ Whether the table is writable or not. It’s not by default. -‐-‐> |
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<xs:element name="writable" type="xs:boolean" minOccurs="0"/> |
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<!-‐-‐ Specify the maxi entries in the table. Default is 16. -‐-‐> |
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<xs:element name="maxEntries" type="xs:positiveInteger" minOccurs="0"/> |
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<!-‐-‐ Cache is always recommended for performance concerns. The default is 30 seconds -‐-‐> |
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<xs:element name="cacheTimeout" type="xs:nonNegativeInteger" minOccurs="0" /> |
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<!-‐-‐ In some special case, the mib table maps to some entries in a DM table. -‐-‐> |
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<!-‐-‐ The filter may be added here to achieve this goal. For instance, “Routing.%d.type = static” -‐-‐> |
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<xs:element name="mapToEntries" type="xs:string" minOccurs="0" /> |
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<!-‐-‐ If callback/hook functions are needed for this group, add it here. -‐-‐> |
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<xs:element name="callbacks" type="callbackInfo " minOccurs="0" /> |
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<!-‐-‐ a set of indexs -‐-‐> |
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<xs:element name="index" type="indexInfo" minOccurs="1" maxOccurs="8"/> |
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<!-‐-‐ a set of mibs -‐-‐> |
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<xs:element name="mapping" type="mappingInfo" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> |
Complete Schema
Find a sample Complete_Schema.xml .
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