Utility Functions

Utility functions for net-snmp agent for SNMP support. More...

Collaboration diagram for Utility Functions:

Functions
val_value_t *	agt_ypsnmp_bestmatch_next_index (yangapi_cb_t *rcb)
	Find the next best matching list entry in the Queue. More...
val_value_t *	agt_ypsnmp_get_first_getnextlist (yangapi_cb_t *rcb)
	Get the first list val_value structure in getnext_listQ. More...
val_value_t *	agt_ypsnmp_get_next_getnextlist (val_value_t *list)
	Get the next list val_value structure in getnext_listQ. More...
boolean	agt_ypsnmp_match_obj (obj_template_t *targetobj, obj_template_t *curobj)
	Checks if the current object in the walker is the target object for the request. More...
boolean	agt_ypsnmp_match_index (yangapi_cb_t *rcb, val_value_t *keyval)
	Checks if the current index in the walker is the target index for the request. More...
obj_template_t *	agt_ypsnmp_get_table_obj (obj_template_t *obj)
	Find the Table object of the current object. More...
obj_template_t *	agt_ypsnmp_get_parent_obj (obj_template_t *obj)
	Find the complex parent of the current leaf object. More...
boolean	agt_ypsnmp_is_scalar_obj (obj_template_t *curobj)
	Check if the object is a scalar object. More...
boolean	agt_ypsnmp_is_augmented_obj (obj_template_t *curobj)
	Check if the object is an augmented object. More...
xmlChar *	agt_ypsnmp_convert_physaddr (val_value_t *val)
	Converts the value of ifPhysAddress leaf element from yang syntax to SMI syntax expected by snmp client. More...
netsnmp_variable_list *	agt_ypsnmp_create_snmp_varbind_object (const oid *name, size_t name_length, u_char type, const void *value, size_t len)
	Allocates and creates a new netsnmp variable binding object. More...
void	agt_ypsnmp_append_varbind_to_list (netsnmp_variable_list **list, netsnmp_variable_list *var)
	Adds the given netsnmp variable binding object to the end of the list of given pdu. More...
obj_oid_t *	agt_ypsnmp_convert_varbind_to_oid (netsnmp_variable_list *var_ptr)
	Converts an SNMP OID string into an internal object. More...
status_t	agt_ypsnmp_set_varbind (ses_cb_t *scb, netsnmp_pdu *pdu, val_value_t *val, const obj_oid_t *oid_obj)
	Set the return Varbind based on the found value. More...
status_t	agt_ypsnmp_setup_peeraddr (ses_cb_t *scb, netsnmp_pdu *pdu)
	Setup the scb->peeraddr for debugging and auditing. More...
yangapi_method_t	agt_ypsnmp_get_yangapi_method (uint8 msg_code)
	Get the YANGAPI method from the SNMP method. More...
xmlChar *	agt_ypsnmp_make_restconf_uri (obj_template_t *obj)
	Make a RESTCONF URI string from the specified OID string. More...
void	agt_ypsnmp_log_pdu (netsnmp_pdu *pdu)
	logs the received SNMP PDU packet contents More...
const void *	agt_ypsnmp_get_varbind_value (netsnmp_variable_list *var)
	Get the Varbind value. More...
const xmlChar *	agt_ypsnmp_get_getnext_modename (ypsnmp_getnext_mode_t getnextmode)
	Get the getnext mode name from its enum. More...
obj_oid_t *	agt_ypsnmp_get_index_oid (obj_oid_t *full_oid, uint32 index_length)
	parse requested OID and strip out index OID More...
status_t	agt_ypsnmp_convert_oid2chars (xmlChar *str, uint32 len, const oid_t *useoid)
	Converts an OID to its character form. More...
status_t	agt_ypsnmp_convert_str_oid2str (xmlChar *str, uint32 len, oid_t *useoid)
	Converts a string OID to its string form. More...
status_t	agt_ypsnmp_convert_str2oid (const xmlChar *str, oid_t *useoid, uint32 len)
	Converts a string to its OID form. More...
status_t	agt_ypsnmp_indexoid_to_value (yangapi_cb_t *rcb, obj_template_t *obj, uint32 index_length)
	Parse requested OID and strip out index OID. More...
status_t	agt_ypsnmp_value_to_indexoid (yangapi_cb_t *rcb, val_value_t *list)
	Converts val_value list with keys into index OID. More...
ypsnmp_agent_session_t *	agt_ypsnmp_init_agent_session (netsnmp_session *session, netsnmp_pdu *pdu)
	Allocate new ypsnmp session context. More...
void	agt_ypsnmp_free_agent_session (ypsnmp_agent_session_t *asp)
	free the ypsnmp session and deallocate any associated memory More...
void	free_varbind (netsnmp_variable_list *var)
	Frees the variable and any malloc'd data associated with it. More...
void	free_varbind_yp (netsnmp_variable_list *var)
	Frees the variable and any malloc'd data associated with it. More...

Detailed Description

Utility functions for net-snmp agent for SNMP support.

Requires WITH_SNMP=1 in build and –with-snmp=true CLI parameter at runtime.

Function Documentation

agt_ypsnmp_append_varbind_to_list()

void agt_ypsnmp_append_varbind_to_list	(	netsnmp_variable_list **	list,
		netsnmp_variable_list *	var
	)

Adds the given netsnmp variable binding object to the end of the list of given pdu.

Only present if WITH_SNMP=1.

Parameters

list	address of varbind list to add to
var	variable binding object

agt_ypsnmp_bestmatch_next_index()

val_value_t * agt_ypsnmp_bestmatch_next_index

(

yangapi_cb_t *

rcb

)

Find the next best matching list entry in the Queue.

Only present if WITH_SNMP=1.

Parameters

rcb	restapi request control block to use

Returns

pointer to the entry or NULL

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agt_ypsnmp_convert_oid2chars()

status_t agt_ypsnmp_convert_oid2chars	(	xmlChar *	str,
		uint32	len,
		const oid_t *	useoid
	)

Converts an OID to its character form.

in example 5 . 1 . 2 . 3 . 4 . 5 = 12345

Only present if WITH_SNMP=1.

Parameters

[out]	str	buffer to fill in
	len	length of the buffer.
	useoid	the oid.

Returns

status

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agt_ypsnmp_convert_physaddr()

xmlChar * agt_ypsnmp_convert_physaddr

(

val_value_t *

val

)

Converts the value of ifPhysAddress leaf element from yang syntax to SMI syntax expected by snmp client.

Only present if WITH_SNMP=1.

Parameters

val

val node

Returns

smi_value converted value of ifPhysAddress

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agt_ypsnmp_convert_str2oid()

status_t agt_ypsnmp_convert_str2oid	(	const xmlChar *	str,
		oid_t *	useoid,
		uint32	len
	)

Converts a string to its OID form.

in example "hello" = 5 . 'h' . 'e' . 'l' . 'l' . 'o'

Only present if WITH_SNMP=1.

Parameters

[out]	str	buffer to fill in
	useoid	the oid.
	len	the length of the oid.

Returns

status

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agt_ypsnmp_convert_str_oid2str()

status_t agt_ypsnmp_convert_str_oid2str	(	xmlChar *	str,
		uint32	len,
		oid_t *	useoid
	)

Converts a string OID to its string form.

in example 5 . 'h' . 'e' . 'l' . 'l' . 'o' = "hello\0" (null terminated)

Only present if WITH_SNMP=1.

Parameters

[out]	str	buffer to fill in
	len	the length of the buffer.
	useoid	the oid.

Returns

status

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agt_ypsnmp_convert_varbind_to_oid()

obj_oid_t * agt_ypsnmp_convert_varbind_to_oid

(

netsnmp_variable_list *

var_ptr

)

Converts an SNMP OID string into an internal object.

Only present if WITH_SNMP=1.

Parameters

var_ptr

pointer to the varbind

Returns

pointer to new ypsnmp session context on success, NULL on error

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agt_ypsnmp_create_snmp_varbind_object()

netsnmp_variable_list * agt_ypsnmp_create_snmp_varbind_object	(	const oid *	name,
		size_t	name_length,
		u_char	type,
		const void *	value,
		size_t	len
	)

Allocates and creates a new netsnmp variable binding object.

Add a variable with the requested name to the end of the list of variables for this pdu.

Only present if WITH_SNMP=1.

Parameters

name	oid value
name_length	length of above oid
type	ASN type
value	value to be set
len	length of the value

Returns

pointer to netsnmp_variable_list, else null

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agt_ypsnmp_free_agent_session()

void agt_ypsnmp_free_agent_session

(

ypsnmp_agent_session_t *

asp

)

free the ypsnmp session and deallocate any associated memory

Only present if WITH_SNMP=1.

Parameters

asp	handle to ypsnmp session to free

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agt_ypsnmp_get_first_getnextlist()

val_value_t * agt_ypsnmp_get_first_getnextlist

(

yangapi_cb_t *

rcb

)

Get the first list val_value structure in getnext_listQ.

Only present if WITH_SNMP=1.

Parameters

rcb	restapi request control block to use

Returns

pointer to the first entry or NULL if empty Q

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agt_ypsnmp_get_getnext_modename()

const xmlChar * agt_ypsnmp_get_getnext_modename

(

ypsnmp_getnext_mode_t

getnextmode

)

Get the getnext mode name from its enum.

Only present if WITH_SNMP=1.

Parameters

getnextmode

getnext mode name enumeration

Returns

string for the enumeration

agt_ypsnmp_get_index_oid()

obj_oid_t * agt_ypsnmp_get_index_oid	(	obj_oid_t *	full_oid,
		uint32	index_length
	)

parse requested OID and strip out index OID

Only present if WITH_SNMP=1.

Parameters

full_oid	complete requested OID
index_length	length of the index, how mane .x.y.z...

Returns

Index OID appended after base OID

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agt_ypsnmp_get_next_getnextlist()

val_value_t * agt_ypsnmp_get_next_getnextlist

(

val_value_t *

list

)

Get the next list val_value structure in getnext_listQ.

Only present if WITH_SNMP=1.

Parameters

list	current list entry

Returns

pointer to the next entry or NULL

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agt_ypsnmp_get_parent_obj()

obj_template_t * agt_ypsnmp_get_parent_obj

(

obj_template_t *

obj

)

Find the complex parent of the current leaf object.

Skips:

• augments
• choice and cases Stops only on list or container

Only present if WITH_SNMP=1.

Parameters

obj	leaf obj_template to use

Returns

pointer to complex parent object or NULL if none or not found

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agt_ypsnmp_get_table_obj()

obj_template_t * agt_ypsnmp_get_table_obj

(

obj_template_t *

obj

)

Find the Table object of the current object.

Skips:

• augments
• choice and cases Stops only on container

Only present if WITH_SNMP=1.

Parameters

obj	current obj_template to use

Returns

pointer to Table parent object or NULL if none or not found

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agt_ypsnmp_get_varbind_value()

const void * agt_ypsnmp_get_varbind_value

(

netsnmp_variable_list *

var

)

Get the Varbind value.

Only present if WITH_SNMP=1.

Parameters

var	varbind variable

Returns

variable value from varbind

agt_ypsnmp_get_yangapi_method()

yangapi_method_t agt_ypsnmp_get_yangapi_method

(

uint8

msg_code

)

Get the YANGAPI method from the SNMP method.

Only present if WITH_SNMP=1.

Parameters

msg_code

uint8 SNMP pdu command code

Returns

YANGAPI method enum

agt_ypsnmp_indexoid_to_value()

status_t agt_ypsnmp_indexoid_to_value	(	yangapi_cb_t *	rcb,
		obj_template_t *	obj,
		uint32	index_length
	)

Parse requested OID and strip out index OID.

For tabular objects ONLY. Converts index OID into val_value, saves all key values into Q of val_values

Only present if WITH_SNMP=1.

  RFC 1902
  7.7.  Mapping of the INDEX clause

   The INDEX clause, which must be present if that object corresponds to
    a conceptual row (unless an AUGMENTS clause is present instead), and
    must be absent otherwise, defines instance identification information
    for the columnar objects subordinate to that object.

    The instance identification information in an INDEX clause must
    specify object(s) such that value(s) of those object(s) will
    unambiguously distinguish a conceptual row.  The syntax of those
    objects indicate how to form the instance-identifier:

*(1)  integer-valued:  a single sub-identifier taking the integer value
      (this works only for non-negative integers);

*(2)  string-valued, fixed-length strings (or variable-length preceded by
      the IMPLIED keyword):  `n' sub-identifiers, where `n' is the length
      of the string (each octet of the string is encoded in a separate
      sub-identifier);

*(3)  string-valued, variable-length strings (not preceded by the IMPLIED
      keyword):  `n+1' sub-identifiers, where `n' is the length of the
      string (the first sub-identifier is `n' itself, following this,
      each octet of the string is encoded in a separate sub-identifier);

*(4)  object identifier-valued (when preceded by the IMPLIED keyword):
      `n' sub-identifiers, where `n' is the number of sub-identifiers in
      the value (each sub-identifier of the value is copied into a
      separate sub-identifier);

*(5)  object identifier-valued (when not preceded by the IMPLIED
      keyword):  `n+1' sub-identifiers, where `n' is the number of sub-
      identifiers in the value (the first sub-identifier is `n' itself,
      following this, each sub-identifier in the value is copied);

*(6)  IpAddress-valued:  4 sub-identifiers, in the familiar a.b.c.d
      notation.

Parameters

[in,out]	rcb	rest control block rcb->target_keyvalQ malloced and set rcb->target_list malloced and set
	obj	object to use
	index_length	length of the index

Returns

status

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agt_ypsnmp_init_agent_session()

ypsnmp_agent_session_t * agt_ypsnmp_init_agent_session	(	netsnmp_session *	session,
		netsnmp_pdu *	pdu
	)

Allocate new ypsnmp session context.

Only present if WITH_SNMP=1.

Parameters

session	net-snmp session to use
pdu	PDU for context

Returns

pointer to new ypsnmp session context on success, NULL on error

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agt_ypsnmp_is_augmented_obj()

boolean agt_ypsnmp_is_augmented_obj

(

obj_template_t *

curobj

)

Check if the object is an augmented object.

That's, if the object is inside augment statement

Only present if WITH_SNMP=1.

Parameters

curobj

leaf obj_template to use

Returns

TRUE if the curent object is the augmented object

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agt_ypsnmp_is_scalar_obj()

boolean agt_ypsnmp_is_scalar_obj

(

obj_template_t *

curobj

)

Check if the object is a scalar object.

Only present if WITH_SNMP=1.

Parameters

curobj

leaf obj_template to use

Returns

TRUE if the curent object is the scalar object
FALSE if the object is tabular

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agt_ypsnmp_log_pdu()

void agt_ypsnmp_log_pdu

(

netsnmp_pdu *

pdu

)

logs the received SNMP PDU packet contents

Only present if WITH_SNMP=1.

Parameters

pdu	received SNMP protocol data unit (PDU)

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agt_ypsnmp_make_restconf_uri()

xmlChar * agt_ypsnmp_make_restconf_uri

(

obj_template_t *

obj

)

Make a RESTCONF URI string from the specified OID string.

Only present if WITH_SNMP=1.

Parameters

obj	object to make the URI string for

Returns

malloced uri - RESTCONF uri for given pdu, else NULL if unable to generate one

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agt_ypsnmp_match_index()

boolean agt_ypsnmp_match_index	(	yangapi_cb_t *	rcb,
		val_value_t *	keyval
	)

Checks if the current index in the walker is the target index for the request.

Only present if WITH_SNMP=1.

Parameters

rcb	restapi control block to use
keyval	key value to match

Returns

TRUE is the curent object is the target object for the target index

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agt_ypsnmp_match_obj()

boolean agt_ypsnmp_match_obj	(	obj_template_t *	targetobj,
		obj_template_t *	curobj
	)

Checks if the current object in the walker is the target object for the request.

Only present if WITH_SNMP=1.

Parameters

targetobj	first obj_template to use
curobj	another obj_template to use for compar

Returns

TRUE is the curent object is the target object for the target index

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agt_ypsnmp_set_varbind()

status_t agt_ypsnmp_set_varbind	(	ses_cb_t *	scb,
		netsnmp_pdu *	pdu,
		val_value_t *	val,
		const obj_oid_t *	oid_obj
	)

Set the return Varbind based on the found value.

The mapping between YANG and SMIv2 data types is defined in RFC6643

rcb->variables is updated with the final return Varbinds. Or pdu->variables is updated in case of Traps responce Only present if WITH_SNMP=1.

Parameters

scb	session control block
pdu	SNMP PDU->varbinds to use instead of SCB->varbinds
val	found value to use
oid_obj	corresponding OID value for the val

Returns

status

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agt_ypsnmp_setup_peeraddr()

status_t agt_ypsnmp_setup_peeraddr	(	ses_cb_t *	scb,
		netsnmp_pdu *	pdu
	)

Setup the scb->peeraddr for debugging and auditing.

Only present if WITH_SNMP=1.

Parameters

scb	session control block to use
pdu	SNMP PDU to use

Returns

status

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agt_ypsnmp_value_to_indexoid()

status_t agt_ypsnmp_value_to_indexoid	(	yangapi_cb_t *	rcb,
		val_value_t *	list
	)

Converts val_value list with keys into index OID.

Only present if WITH_SNMP=1.

Parameters

[in,out]	rcb	yangapi control block to use. rcb->index_oid malloced and set rcb->index_oid->oidc set rcb->index_oid->cnt set
	list	list val_value node with only keys in it

Returns

status

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free_varbind()

void free_varbind

(

netsnmp_variable_list *

var

)

Frees the variable and any malloc'd data associated with it.

Only present if WITH_SNMP=1.

Parameters

var	variable binding object

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free_varbind_yp()

void free_varbind_yp

(

netsnmp_variable_list *

var

)

Frees the variable and any malloc'd data associated with it.

Using m__free API

Only present if WITH_SNMP=1.

Parameters

var	variable binding object