DOC HOME SITE MAP MAN PAGES GNU INFO SEARCH PRINT BOOK
 
Developing SMUX peers for SNMP agents

Syntax

The syntax of MIB objects is modeled by the OS (Object Syntax) structure:

typedef int (*IFP) ();

typedef struct object_syntax { char *os_name; /* syntax name */

int os_type; /* syntax type */ IFP os_decode; IFP os_free; /* free data */

} *OS; #define NULLOS ((OS) 0)

The syntaxes defined by the Internet-standard MIB are already implemented:

Internet-standard MIB defined syntaxes

Syntax Structure type
INTEGER integer
OctetString struct _OctetString
ObjectID struct OIDentifier
NULL char
DisplayString struct _OctetString
IpAddress struct sockaddr_in
NetworkAddress struct sockaddr_in
Counter integer
Gauge integer
TimeTicks integer
ClnpAddress struct _OctetString
where ``syntax'' is the name appearing in a compiled MIB module, and ``structure type'' is the C language data type corresponding to the object's syntax. The structure types are described below.

To take a syntax name and get back the structure, use the routine text2syn().

Here are the structures and routines used to implement some of these low-level MIB abstractions: Integer, OctetString, ObjectID, and IPAddress.

INTEGER, Counter, Gauge, and TimeTicks

integer is used for the INTEGER, Counter, Gauge, and TimeTicks syntaxes. The definition is:

typedef int integer;

OctetString, DisplayString, and ClnpAddress

struct _OctetString is used for the OctetString, DisplayString, and ClnpAddress syntaxes. The definition is:

typedef struct _OctetString {
	unsigned char *octet_ptr;   /* list of octets */
	long     length;            /* number of elements */
};

ObjectID

struct OIDentifier is used for the ObjectID syntax. The definition is:

typedef struct OIDentifier {
	int     oid_nelem;  /* number of sub-identifiers */

unsigned int *oid_elements; /* the (ordered) list of sub-identifiers */ } OIDentifier, *OID; #define NULLOID ((OID) 0)

IPAddress and NetworkAddress

struct sockaddr_in is used for the IpAddress and NetworkAddress syntaxes. It is assumed that you are familiar with this structure. If not, consult the file /usr/include/sys/netinet/in.h.


© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 27 April 2004