asn1_enc.c File Reference

Functions
void	snmp_asn1_enc_length_cnt (u16_t length, u8_t *octets_needed)
void	snmp_asn1_enc_u32t_cnt (u32_t value, u16_t *octets_needed)
void	snmp_asn1_enc_s32t_cnt (s32_t value, u16_t *octets_needed)
void	snmp_asn1_enc_oid_cnt (u8_t ident_len, s32_t *ident, u16_t *octets_needed)
err_t	snmp_asn1_enc_type (struct pbuf *p, u16_t ofs, u8_t type)
err_t	snmp_asn1_enc_length (struct pbuf *p, u16_t ofs, u16_t length)
err_t	snmp_asn1_enc_u32t (struct pbuf *p, u16_t ofs, u8_t octets_needed, u32_t value)
err_t	snmp_asn1_enc_s32t (struct pbuf *p, u16_t ofs, u8_t octets_needed, s32_t value)
err_t	snmp_asn1_enc_oid (struct pbuf *p, u16_t ofs, u8_t ident_len, s32_t *ident)
err_t	snmp_asn1_enc_raw (struct pbuf *p, u16_t ofs, u8_t raw_len, u8_t *raw)

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Detailed Description

Abstract Syntax Notation One (ISO 8824, 8825) encoding

Todo:

not optimised (yet), favor correctness over speed, favor speed over size

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Function Documentation

err_t snmp_asn1_enc_length	(	struct pbuf *	p,
		u16_t	ofs,
		u16_t	length
	)

Encodes host order length field into a pbuf chained ASN1 msg.

Parameters:

	p	points to output pbuf to encode length into
	ofs	points to the offset within the pbuf chain
	length	is the host order length to be encoded

Returns:

ERR_OK if successfull, ERR_ARG if we can't (or won't) encode

void snmp_asn1_enc_length_cnt	(	u16_t	length,
		u8_t *	octets_needed
	)

Returns octet count for length.

Parameters:

	length
	octets_needed	points to the return value

err_t snmp_asn1_enc_oid	(	struct pbuf *	p,
		u16_t	ofs,
		u8_t	ident_len,
		s32_t *	ident
	)

Encodes object identifier into a pbuf chained ASN1 msg.

Parameters:

	p	points to output pbuf to encode oid into
	ofs	points to the offset within the pbuf chain
	ident_len	object identifier array length
	ident	points to object identifier array

Returns:

ERR_OK if successfull, ERR_ARG if we can't (or won't) encode

void snmp_asn1_enc_oid_cnt	(	u8_t	ident_len,
		s32_t *	ident,
		u16_t *	octets_needed
	)

Returns octet count for an object identifier.

Parameters:

	ident_len	object identifier array length
	ident	points to object identifier array
	octets_needed	points to the return value

err_t snmp_asn1_enc_raw	(	struct pbuf *	p,
		u16_t	ofs,
		u8_t	raw_len,
		u8_t *	raw
	)

Encodes raw data (octet string, opaque) into a pbuf chained ASN1 msg.

Parameters:

	p	points to output pbuf to encode raw data into
	ofs	points to the offset within the pbuf chain
	raw_len	raw data length
	raw	points raw data

Returns:

ERR_OK if successfull, ERR_ARG if we can't (or won't) encode

err_t snmp_asn1_enc_s32t	(	struct pbuf *	p,
		u16_t	ofs,
		u8_t	octets_needed,
		s32_t	value
	)

Encodes s32_t integer into a pbuf chained ASN1 msg.

Parameters:

	p	points to output pbuf to encode value into
	ofs	points to the offset within the pbuf chain
	octets_needed	encoding length (from snmp_asn1_enc_s32t_cnt())
	value	is the host order s32_t value to be encoded

Returns:

ERR_OK if successfull, ERR_ARG if we can't (or won't) encode

See also:

snmp_asn1_enc_s32t_cnt()

void snmp_asn1_enc_s32t_cnt	(	s32_t	value,
		u16_t *	octets_needed
	)

Returns octet count for an s32_t.

Parameters:

	value
	octets_needed	points to the return value

Note:

ASN coded integers are _always_ signed.

err_t snmp_asn1_enc_type	(	struct pbuf *	p,
		u16_t	ofs,
		u8_t	type
	)

Encodes ASN type field into a pbuf chained ASN1 msg.

Parameters:

	p	points to output pbuf to encode value into
	ofs	points to the offset within the pbuf chain
	type	input ASN1 type

Returns:

ERR_OK if successfull, ERR_ARG if we can't (or won't) encode

err_t snmp_asn1_enc_u32t	(	struct pbuf *	p,
		u16_t	ofs,
		u8_t	octets_needed,
		u32_t	value
	)

Encodes u32_t (counter, gauge, timeticks) into a pbuf chained ASN1 msg.

Parameters:

	p	points to output pbuf to encode value into
	ofs	points to the offset within the pbuf chain
	octets_needed	encoding length (from snmp_asn1_enc_u32t_cnt())
	value	is the host order u32_t value to be encoded

Returns:

ERR_OK if successfull, ERR_ARG if we can't (or won't) encode

See also:

snmp_asn1_enc_u32t_cnt()

void snmp_asn1_enc_u32t_cnt	(	u32_t	value,
		u16_t *	octets_needed
	)

Returns octet count for an u32_t.

Parameters:

	value
	octets_needed	points to the return value

Note:

ASN coded integers are _always_ signed. E.g. +0xFFFF is coded as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!!

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