varbind(SLIB)

Syntax

#include <snmp/snmp.h>

void
free_varbind_list(vbl_ptr)
VarBindList *vbl_ptr;

short
link_varbind(pdu_ptr, vbl_ptr);
Pdu *pdu_ptr; 		/* ptr to PDU header allocated by make_pdu */
VarBindList *vbl_ptr; 	/* ptr to VarBindList created by make_varbind */

short
link_varbind_list(pdu_ptr, vbl_ptr);
Pdu *pdu_ptr; 		/* ptr. to PDU header alloc'ed by make_pdu */
VarBindList *vbl_ptr; 	/* ptr. to VarBindList created by make_varbind */

VarBindList *
make_varbind(oid_ptr, type, ul_value, sl_value, os_value, \
	     oid_value, c64_value)
OID oid_ptr;
short type;		/* variable type: INTEGER_TYPE, COUNTER_TYPE, etc. */
unsigned long ul_value;	/* COUNTER_TYPE, GAUGE_TYPE, etc. values */
long sl_value; 		/* INTEGER_TYPE values */
OctetString *os_value;	/* OCTET_PRIM_TYPE, BITSTRING_TYPE, etc. values */
OID oid_value; 		/* OBJECT_ID_TYPE value */
Counter64 *c64_value; 	/* COUNTER64_TYPE value */

#include <snmp/snmp.h>
#include <snmp/snmpuser.h>

short
print_varbind_list(vbl_ptr)
VarBindList *vbl_ptr; 	/* ptr to a VarBindList to be printed out */

Description

link_varbind completes a PDU, created by a call to make_pdu(SLIB), by adding the VarBindList entry created by a call to make_varbind(SLIB). link_varbind should be called exactly once for each vbl_ptr being associated with the PDU as this association is used to reclaim memory when the PDU is freed.

link_varbind_list appends a list of variable bindings to a PDU structure. It invokes the link_varbind routine repeatedly (once for each variable binding in the list) to accomplish this task. The arguments supplied to this function are pointers to a PDU (pdu_ptr) and a list of variable bindings (vbl_ptr) that need to be added to the PDU (1st argument).

make_varbind is called to create a VarBindList entry to be strung onto a PDU. It returns a pointer to a malloc'ed data structure of the type VarBind. Usually, this pointer is then used in a call to link_varbind to associate this VarBindList with a PDU. The structure is freed when the PDU is freed with a call to free_pdu(SLIB).

A VarBindList is a variable-value binding. It binds the name, the type, and the value of a variable into one construct. The current list of SNMP types and the value type associated with each is:

COUNTER_TYPE

uses ul_value

GAUGE_TYPE

uses ul_value

INTEGER_TYPE

uses sl_value

UINTEGER_TYPE

uses ul_value

TIME_TICKS_TYPE

uses ul_value

OBJECT_ID_TYPE

uses oid_value

OCTET_PRIM_TYPE

uses os_value

IP_ADDR_PRIM_TYPE

uses os_value

OPAQUE_PRIM_TYPE

uses os_value

COUNTER64_TYPE

uses c64_value

NULL_TYPE

no passed value needed

print_varbind_list prints out the contents of a VarBindList in a human readable form. This is a quick user interface for printing out the SNMP responses in simple SNMP utilities. If the PDU structure is pointed to by *pdu_ptr, the call is:

print_varbind_list(pdu_ptr->var_bind_list)

See also