msg_out.c File Reference

SNMP output message processing (RFC1157). More...

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Functions
static u16_t	snmp_resp_header_sum (struct snmp_msg_pstat *m_stat, u16_t vb_len)
	Sums response header field lengths from tail to head and returns resp_header_lengths for second encoding pass.
static u16_t	snmp_trap_header_sum (struct snmp_msg_trap *m_trap, u16_t vb_len)
	Sums trap header field lengths from tail to head and returns trap_header_lengths for second encoding pass.
static u16_t	snmp_varbind_list_sum (struct snmp_varbind_root *root)
	Sums varbind lengths from tail to head and annotates lengths in varbind for second encoding pass.
static u16_t	snmp_resp_header_enc (struct snmp_msg_pstat *m_stat, struct pbuf *p)
	Encodes response header from head to tail.
static u16_t	snmp_trap_header_enc (struct snmp_msg_trap *m_trap, struct pbuf *p)
	Encodes trap header from head to tail.
static u16_t	snmp_varbind_list_enc (struct snmp_varbind_root *root, struct pbuf *p, u16_t ofs)
	Encodes varbind list from head to tail.
void	snmp_trap_dst_enable (u8_t dst_idx, u8_t enable)
	Sets enable switch for this trap destination.
void	snmp_trap_dst_ip_set (u8_t dst_idx, ip_addr_t *dst)
	Sets IPv4 address for this trap destination.
err_t	snmp_send_response (struct snmp_msg_pstat *m_stat)
	Sends a 'getresponse' message to the request originator.
err_t	snmp_send_trap (s8_t generic_trap, struct snmp_obj_id *eoid, s32_t specific_trap)
	Sends an generic or enterprise specific trap message.
Variables
struct snmp_msg_trap	trap_msg
	TRAP message structure.

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Detailed Description

SNMP output message processing (RFC1157).

Output responses and traps are build in two passes:

Pass 0: iterate over the output message backwards to determine encoding lengths Pass 1: the actual forward encoding of internal form into ASN1

The single-pass encoding method described by Comer & Stevens requires extra buffer space and copying for reversal of the packet. The buffer requirement can be prohibitively large for big payloads (>= 484) therefore we use the two encoding passes.

Definition in file msg_out.c.

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Function Documentation

static u16_t snmp_resp_header_enc	(	struct snmp_msg_pstat *	m_stat,
		struct pbuf *	p
	)		[static]

Encodes response header from head to tail.

Definition at line 490 of file msg_out.c.

static u16_t snmp_resp_header_sum	(	struct snmp_msg_pstat *	m_stat,
		u16_t	vb_len
	)		[static]

Sums response header field lengths from tail to head and returns resp_header_lengths for second encoding pass.

Parameters:

vb_len	varbind-list length
rhl	points to returned header lengths

Returns:

the required lenght for encoding the response header

Definition at line 322 of file msg_out.c.

err_t snmp_send_response

(

struct snmp_msg_pstat *

m_stat )

Sends a 'getresponse' message to the request originator.

Parameters:

m_stat

points to the current message request state source

Returns:

ERR_OK when success, ERR_MEM if we're out of memory

Note:

the caller is responsible for filling in outvb in the m_stat and provide error-status and index (except for tooBig errors) ...

connect to the originating source

disassociate remote address and port with this pcb

Definition at line 113 of file msg_out.c.

err_t snmp_send_trap	(	s8_t	generic_trap,
		struct snmp_obj_id *	eoid,
		s32_t	specific_trap
	)

Sends an generic or enterprise specific trap message.

Parameters:

generic_trap	is the trap code
eoid	points to enterprise object identifier
specific_trap	used for enterprise traps when generic_trap == 6

Returns:

ERR_OK when success, ERR_MEM if we're out of memory

Note:

the caller is responsible for filling in outvb in the trap_msg

the use of the enterpise identifier field is per RFC1215. Use .iso.org.dod.internet.mgmt.mib-2.snmp for generic traps and .iso.org.dod.internet.private.enterprises.yourenterprise (sysObjectID) for specific traps.

connect to the TRAP destination

disassociate remote address and port with this pcb

Definition at line 220 of file msg_out.c.

void snmp_trap_dst_enable	(	u8_t	dst_idx,
		u8_t	enable
	)

Sets enable switch for this trap destination.

Parameters:

dst_idx	index in 0 .. SNMP_TRAP_DESTINATIONS-1
enable	switch if 0 destination is disabled >0 enabled.

Definition at line 81 of file msg_out.c.

void snmp_trap_dst_ip_set	(	u8_t	dst_idx,
		ip_addr_t *	dst
	)

Sets IPv4 address for this trap destination.

Parameters:

dst_idx	index in 0 .. SNMP_TRAP_DESTINATIONS-1
dst	IPv4 address in host order.

Definition at line 95 of file msg_out.c.

static u16_t snmp_trap_header_enc	(	struct snmp_msg_trap *	m_trap,
		struct pbuf *	p
	)		[static]

Encodes trap header from head to tail.

Definition at line 547 of file msg_out.c.

static u16_t snmp_trap_header_sum	(	struct snmp_msg_trap *	m_trap,
		u16_t	vb_len
	)		[static]

Sums trap header field lengths from tail to head and returns trap_header_lengths for second encoding pass.

Parameters:

vb_len	varbind-list length
thl	points to returned header lengths

Returns:

the required lenght for encoding the trap header

Definition at line 369 of file msg_out.c.

static u16_t snmp_varbind_list_enc	(	struct snmp_varbind_root *	root,
		struct pbuf *	p,
		u16_t	ofs
	)		[static]

Encodes varbind list from head to tail.

Definition at line 618 of file msg_out.c.

static u16_t snmp_varbind_list_sum

(

struct snmp_varbind_root *

root )

[static]

Sums varbind lengths from tail to head and annotates lengths in varbind for second encoding pass.

Parameters:

root	points to the root of the variable binding list

Returns:

the required lenght for encoding the variable bindings

Definition at line 424 of file msg_out.c.

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Variable Documentation

struct snmp_msg_trap trap_msg

TRAP message structure.

Definition at line 65 of file msg_out.c.