Most of the general types are defined as type definitions (#typedef) in the header file asn1conf.h. You should not modify this file.

The fully decoded value of an ASN.1 length field.

The fully decoded value of an ASN.1 tag, excluding the context and constructor bits.

Signed 16-bit integer.

Signed 32-bit integer. MIB variables of type Integer ought to be of this type.

Unsigned 8-bit character.

An object identifier component. By default this is a 32-bit unsigned integer.

Unsigned 8-bit integer.

Unsigned 16-bit integer.

Unsigned 32-bit integer. MIB variables of type Counter, Gauge, and TimeTicks ought to be of this type.

Variables of type EBUFFER_T are used to hold strings of bytes generated by the ASN.1 encoding routines. EBUFFER_T is also used as a general mechanism for managing variable length byte strings.

The EBUFFER_T type does not itself include the storage to hold the byte string. That storage is provided by the user of the EBUFFER_T. Such storage may be dynamic or static (relative to the lifetime of the EBUFFER_T variable itself.)

An ASN.1 object identifier, in local representation. Manipulation of data structures of this type comprises a significant portion of the execution time used by this SNMP implementation.

A generic void pointer.

This type is used to hold network addresses in a general way. It is very similar to the sockaddr structure used with the Berkeley socket interface.

Each instance of type MIBLEAF_T represents a scalar (non-tabular) management variable, or an attribute (column) in a table of management variables. The MIBLEAF_T instance points to procedures and other information needed to access the associated management variable.

Each instance of type MIBNODE_T represents an internal node of the management information base tree. Each MIBNODE_T is associated with a list of elements of type MIBARC_T. This list indicates the MIBNODE_T and MIBLEAF_T variables at the next lower level of the MIB tree.

Instances of MIBARC_T are used to designate the nodes and leaves of the management information tree which descend from a particular internal node of the tree.

An SNMP packet is represented internally by an element of type SNMP_PKT_T. This type contains a tagged union with two principal variations, one for REQUEST and RESPONSE PDUs, the other for TRAP PDUs.

Various additional fields are present to give the MIB developer a means to determine access privileges, MIB views, etc. (for more detailed information, see the definition for the internal representation of an SNMP packet in the file snmpdefs.h). In addition, a pointer is provided (user_private) through which a developer may attach a private data structure. This memory can be released using a private-memory-deallocation hook (see 4.8 Hooks) when the packet has finished processing (the hook is installed during initialization, in the routine snmpdInitFinish( )).

Each VarBind (see 4.11 Request Processing) in an SNMP PDU's VarBindList is held in an item of type VB_T. This type contains a tagged union capable of holding all of the data types defined by the RFC 1155 and RFC 1902 SMIs.

The VB_T structure contains additional fields which are intended to be used by a MIB designer when processing incoming PDUs (during the method-routine phase). One of these fields is a linked-list pointer giving the MIB developer the means to generate a relationship between items in a VarBindList. Two other fields are provided to allow the MIB developer to associate space with a VB_T item, and to have that space deallocated when the VB_T is freed. These are intended for use when a test routine must acquire some resources to determine if a SET may be accomplished. The vb_priv field in the VB_T may be used to point to these resources while the vb_free_priv field is used to point to a routine which frees user-defined memory. If vb_free_priv is non-null when a packet is being deallocated, the routine pointed to by vb_free_priv is called and may free up any resources that the VB_T specifies.

In general, the VarBindList found in SNMP PDUs is represented as an array of elements of type VB_T. The location and size of such an array is held in an item of type VBL_T. While processing a GET BULK request, where the number of VB_T variables is not known when the packet is created, additional VBL_T variables may be chained in a list using a pointer in the VBL_T structure.