Registering SNMP table rows and cells

Register per-row read callbacks and per-cell write callbacks for tabular MIB objects, and remove rows at runtime. More...

Typedefs
typedef void	TableElementFunc(SNMP_Request &req, void *data_el, int subid)
	Signature of a table-element read callback.

Functions
void	AddToIndex (int asn_type, snmp_typeInteger32 val, int &len, int *oidadd)
	Append a value to the OID index being constructed for a table row.
void	AddSnmpEntry (int subid, const char *root, int add_len, int *suffix, TableElementFunc *pf, void *pData, uint32_t comm_mask)
	Register a read entry for one column of an SNMP table row.
void	AddSnmpWriteEntry (int asn_type, const char *root, int add_len, int *suffix, PutIFuncTab *pf, void *pData, uint32_t comm_mask)
	Register a write callback for a single cell of an SNMP table.
void	SnmpRemoveTableElement (const char *root, void *data_el)
	Remove a previously registered table element from the SNMP agent.

Detailed Description

Register per-row read callbacks and per-cell write callbacks for tabular MIB objects, and remove rows at runtime.

Typedef Documentation

TableElementFunc

typedef void TableElementFunc(SNMP_Request &req, void *data_el, int subid)

#include <snmp_table.h>

Signature of a table-element read callback.

Called by the agent when an SNMP request targets an entry in a table registered with AddSnmpEntry. The callback is responsible for emitting the value for the requested sub-identifier.

Parameters

req	Current SNMP request context.
data_el	User pointer supplied at registration time (per-row context).
subid	Column sub-identifier within the table row.

Function Documentation

AddSnmpEntry()

void AddSnmpEntry	(	int	subid,
		const char *	root,
		int	add_len,
		int *	suffix,
		TableElementFunc *	pf,
		void *	pData,
		uint32_t	comm_mask )

#include <snmp_table.h>

Register a read entry for one column of an SNMP table row.

Parameters

subid	Column sub-identifier within the row.
root	Base OID of the table (e.g. "1.3.6.1.4.1.8174.20.1").
add_len	Length of the per-row index suffix.
suffix	Per-row index components appended after root.
pf	Callback invoked on GET / GETNEXT for this column.
pData	Per-row context pointer passed to pf.
comm_mask	Community mask, typically READ_COMMUNITY_MASK.

AddSnmpWriteEntry()

void AddSnmpWriteEntry	(	int	asn_type,
		const char *	root,
		int	add_len,
		int *	suffix,
		PutIFuncTab *	pf,
		void *	pData,
		uint32_t	comm_mask )

#include <snmp_table.h>

Register a write callback for a single cell of an SNMP table.

Overloaded on every table write-callback signature in Read/write callback function signatures — the compiler picks the matching overload based on the signature of pf.

Parameters

asn_type	One of the ASN_type* tags for the column's value.
root	Base OID of the table.
add_len	Length of the per-row index suffix.
suffix	Per-row index components appended after root.
pf	Write callback for the column.
pData	Per-row context pointer passed to pf.
comm_mask	Community mask, typically WRITE_COMMUNITY_MASK.

AddToIndex()

void AddToIndex	(	int	asn_type,
		snmp_typeInteger32	val,
		int &	len,
		int *	oidadd )

#include <snmp_table.h>

Append a value to the OID index being constructed for a table row.

Call from a TableElementFunc to build the row's full OID from its index components. Overloaded on every SMI type in SMI type aliases, ASN.1 tags, and SET return codes — the compiler picks the right one based on the type of val.

Parameters

asn_type	The ASN_type* tag that matches the type of val.
val	The index component value to append.
len	Running length of the OID; incremented by this call.
oidadd	OID buffer to append into.

SnmpRemoveTableElement()

void SnmpRemoveTableElement	(	const char *	root,
		void *	data_el )

#include <snmp_table.h>

Remove a previously registered table element from the SNMP agent.

Parameters

root	Base OID of the table.
data_el	The per-row context pointer used when registering with AddSnmpEntry.