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This library is stripped down version of NetServices library. HTTP server and client function is NOT supported.

lwip/core/snmp/asn1_enc.c@0:dcf3c92487ca, 2011-07-20 (annotated)

Committer:: idinor
Date:: Wed Jul 20 11:45:39 2011 +0000
Revision:: 0:dcf3c92487ca

Who changed what in which revision?

User	Revision	Line number	New contents of line
idinor	0:dcf3c92487ca	1	/**
idinor	0:dcf3c92487ca	2	* @file
idinor	0:dcf3c92487ca	3	* Abstract Syntax Notation One (ISO 8824, 8825) encoding
idinor	0:dcf3c92487ca	4	*
idinor	0:dcf3c92487ca	5	* @todo not optimised (yet), favor correctness over speed, favor speed over size
idinor	0:dcf3c92487ca	6	*/
idinor	0:dcf3c92487ca	7
idinor	0:dcf3c92487ca	8	/*
idinor	0:dcf3c92487ca	9	* Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
idinor	0:dcf3c92487ca	10	* All rights reserved.
idinor	0:dcf3c92487ca	11	*
idinor	0:dcf3c92487ca	12	* Redistribution and use in source and binary forms, with or without modification,
idinor	0:dcf3c92487ca	13	* are permitted provided that the following conditions are met:
idinor	0:dcf3c92487ca	14	*
idinor	0:dcf3c92487ca	15	* 1. Redistributions of source code must retain the above copyright notice,
idinor	0:dcf3c92487ca	16	* this list of conditions and the following disclaimer.
idinor	0:dcf3c92487ca	17	* 2. Redistributions in binary form must reproduce the above copyright notice,
idinor	0:dcf3c92487ca	18	* this list of conditions and the following disclaimer in the documentation
idinor	0:dcf3c92487ca	19	* and/or other materials provided with the distribution.
idinor	0:dcf3c92487ca	20	* 3. The name of the author may not be used to endorse or promote products
idinor	0:dcf3c92487ca	21	* derived from this software without specific prior written permission.
idinor	0:dcf3c92487ca	22	*
idinor	0:dcf3c92487ca	23	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
idinor	0:dcf3c92487ca	24	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
idinor	0:dcf3c92487ca	25	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
idinor	0:dcf3c92487ca	26	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
idinor	0:dcf3c92487ca	27	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
idinor	0:dcf3c92487ca	28	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
idinor	0:dcf3c92487ca	29	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
idinor	0:dcf3c92487ca	30	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
idinor	0:dcf3c92487ca	31	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
idinor	0:dcf3c92487ca	32	* OF SUCH DAMAGE.
idinor	0:dcf3c92487ca	33	*
idinor	0:dcf3c92487ca	34	* Author: Christiaan Simons <christiaan.simons@axon.tv>
idinor	0:dcf3c92487ca	35	*/
idinor	0:dcf3c92487ca	36
idinor	0:dcf3c92487ca	37	#include "lwip/opt.h"
idinor	0:dcf3c92487ca	38
idinor	0:dcf3c92487ca	39	#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
idinor	0:dcf3c92487ca	40
idinor	0:dcf3c92487ca	41	#include "lwip/snmp_asn1.h"
idinor	0:dcf3c92487ca	42
idinor	0:dcf3c92487ca	43	/**
idinor	0:dcf3c92487ca	44	* Returns octet count for length.
idinor	0:dcf3c92487ca	45	*
idinor	0:dcf3c92487ca	46	* @param length
idinor	0:dcf3c92487ca	47	* @param octets_needed points to the return value
idinor	0:dcf3c92487ca	48	*/
idinor	0:dcf3c92487ca	49	void
idinor	0:dcf3c92487ca	50	snmp_asn1_enc_length_cnt(u16_t length, u8_t *octets_needed)
idinor	0:dcf3c92487ca	51	{
idinor	0:dcf3c92487ca	52	if (length < 0x80U)
idinor	0:dcf3c92487ca	53	{
idinor	0:dcf3c92487ca	54	*octets_needed = 1;
idinor	0:dcf3c92487ca	55	}
idinor	0:dcf3c92487ca	56	else if (length < 0x100U)
idinor	0:dcf3c92487ca	57	{
idinor	0:dcf3c92487ca	58	*octets_needed = 2;
idinor	0:dcf3c92487ca	59	}
idinor	0:dcf3c92487ca	60	else
idinor	0:dcf3c92487ca	61	{
idinor	0:dcf3c92487ca	62	*octets_needed = 3;
idinor	0:dcf3c92487ca	63	}
idinor	0:dcf3c92487ca	64	}
idinor	0:dcf3c92487ca	65
idinor	0:dcf3c92487ca	66	/**
idinor	0:dcf3c92487ca	67	* Returns octet count for an u32_t.
idinor	0:dcf3c92487ca	68	*
idinor	0:dcf3c92487ca	69	* @param value
idinor	0:dcf3c92487ca	70	* @param octets_needed points to the return value
idinor	0:dcf3c92487ca	71	*
idinor	0:dcf3c92487ca	72	* @note ASN coded integers are _always_ signed. E.g. +0xFFFF is coded
idinor	0:dcf3c92487ca	73	* as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value
idinor	0:dcf3c92487ca	74	* of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!!
idinor	0:dcf3c92487ca	75	*/
idinor	0:dcf3c92487ca	76	void
idinor	0:dcf3c92487ca	77	snmp_asn1_enc_u32t_cnt(u32_t value, u16_t *octets_needed)
idinor	0:dcf3c92487ca	78	{
idinor	0:dcf3c92487ca	79	if (value < 0x80UL)
idinor	0:dcf3c92487ca	80	{
idinor	0:dcf3c92487ca	81	*octets_needed = 1;
idinor	0:dcf3c92487ca	82	}
idinor	0:dcf3c92487ca	83	else if (value < 0x8000UL)
idinor	0:dcf3c92487ca	84	{
idinor	0:dcf3c92487ca	85	*octets_needed = 2;
idinor	0:dcf3c92487ca	86	}
idinor	0:dcf3c92487ca	87	else if (value < 0x800000UL)
idinor	0:dcf3c92487ca	88	{
idinor	0:dcf3c92487ca	89	*octets_needed = 3;
idinor	0:dcf3c92487ca	90	}
idinor	0:dcf3c92487ca	91	else if (value < 0x80000000UL)
idinor	0:dcf3c92487ca	92	{
idinor	0:dcf3c92487ca	93	*octets_needed = 4;
idinor	0:dcf3c92487ca	94	}
idinor	0:dcf3c92487ca	95	else
idinor	0:dcf3c92487ca	96	{
idinor	0:dcf3c92487ca	97	*octets_needed = 5;
idinor	0:dcf3c92487ca	98	}
idinor	0:dcf3c92487ca	99	}
idinor	0:dcf3c92487ca	100
idinor	0:dcf3c92487ca	101	/**
idinor	0:dcf3c92487ca	102	* Returns octet count for an s32_t.
idinor	0:dcf3c92487ca	103	*
idinor	0:dcf3c92487ca	104	* @param value
idinor	0:dcf3c92487ca	105	* @param octets_needed points to the return value
idinor	0:dcf3c92487ca	106	*
idinor	0:dcf3c92487ca	107	* @note ASN coded integers are _always_ signed.
idinor	0:dcf3c92487ca	108	*/
idinor	0:dcf3c92487ca	109	void
idinor	0:dcf3c92487ca	110	snmp_asn1_enc_s32t_cnt(s32_t value, u16_t *octets_needed)
idinor	0:dcf3c92487ca	111	{
idinor	0:dcf3c92487ca	112	if (value < 0)
idinor	0:dcf3c92487ca	113	{
idinor	0:dcf3c92487ca	114	value = ~value;
idinor	0:dcf3c92487ca	115	}
idinor	0:dcf3c92487ca	116	if (value < 0x80L)
idinor	0:dcf3c92487ca	117	{
idinor	0:dcf3c92487ca	118	*octets_needed = 1;
idinor	0:dcf3c92487ca	119	}
idinor	0:dcf3c92487ca	120	else if (value < 0x8000L)
idinor	0:dcf3c92487ca	121	{
idinor	0:dcf3c92487ca	122	*octets_needed = 2;
idinor	0:dcf3c92487ca	123	}
idinor	0:dcf3c92487ca	124	else if (value < 0x800000L)
idinor	0:dcf3c92487ca	125	{
idinor	0:dcf3c92487ca	126	*octets_needed = 3;
idinor	0:dcf3c92487ca	127	}
idinor	0:dcf3c92487ca	128	else
idinor	0:dcf3c92487ca	129	{
idinor	0:dcf3c92487ca	130	*octets_needed = 4;
idinor	0:dcf3c92487ca	131	}
idinor	0:dcf3c92487ca	132	}
idinor	0:dcf3c92487ca	133
idinor	0:dcf3c92487ca	134	/**
idinor	0:dcf3c92487ca	135	* Returns octet count for an object identifier.
idinor	0:dcf3c92487ca	136	*
idinor	0:dcf3c92487ca	137	* @param ident_len object identifier array length
idinor	0:dcf3c92487ca	138	* @param ident points to object identifier array
idinor	0:dcf3c92487ca	139	* @param octets_needed points to the return value
idinor	0:dcf3c92487ca	140	*/
idinor	0:dcf3c92487ca	141	void
idinor	0:dcf3c92487ca	142	snmp_asn1_enc_oid_cnt(u8_t ident_len, s32_t ident, u16_t octets_needed)
idinor	0:dcf3c92487ca	143	{
idinor	0:dcf3c92487ca	144	s32_t sub_id;
idinor	0:dcf3c92487ca	145	u8_t cnt;
idinor	0:dcf3c92487ca	146
idinor	0:dcf3c92487ca	147	cnt = 0;
idinor	0:dcf3c92487ca	148	if (ident_len > 1)
idinor	0:dcf3c92487ca	149	{
idinor	0:dcf3c92487ca	150	/* compressed prefix in one octet */
idinor	0:dcf3c92487ca	151	cnt++;
idinor	0:dcf3c92487ca	152	ident_len -= 2;
idinor	0:dcf3c92487ca	153	ident += 2;
idinor	0:dcf3c92487ca	154	}
idinor	0:dcf3c92487ca	155	while(ident_len > 0)
idinor	0:dcf3c92487ca	156	{
idinor	0:dcf3c92487ca	157	ident_len--;
idinor	0:dcf3c92487ca	158	sub_id = *ident;
idinor	0:dcf3c92487ca	159
idinor	0:dcf3c92487ca	160	sub_id >>= 7;
idinor	0:dcf3c92487ca	161	cnt++;
idinor	0:dcf3c92487ca	162	while(sub_id > 0)
idinor	0:dcf3c92487ca	163	{
idinor	0:dcf3c92487ca	164	sub_id >>= 7;
idinor	0:dcf3c92487ca	165	cnt++;
idinor	0:dcf3c92487ca	166	}
idinor	0:dcf3c92487ca	167	ident++;
idinor	0:dcf3c92487ca	168	}
idinor	0:dcf3c92487ca	169	*octets_needed = cnt;
idinor	0:dcf3c92487ca	170	}
idinor	0:dcf3c92487ca	171
idinor	0:dcf3c92487ca	172	/**
idinor	0:dcf3c92487ca	173	* Encodes ASN type field into a pbuf chained ASN1 msg.
idinor	0:dcf3c92487ca	174	*
idinor	0:dcf3c92487ca	175	* @param p points to output pbuf to encode value into
idinor	0:dcf3c92487ca	176	* @param ofs points to the offset within the pbuf chain
idinor	0:dcf3c92487ca	177	* @param type input ASN1 type
idinor	0:dcf3c92487ca	178	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
idinor	0:dcf3c92487ca	179	*/
idinor	0:dcf3c92487ca	180	err_t
idinor	0:dcf3c92487ca	181	snmp_asn1_enc_type(struct pbuf *p, u16_t ofs, u8_t type)
idinor	0:dcf3c92487ca	182	{
idinor	0:dcf3c92487ca	183	u16_t plen, base;
idinor	0:dcf3c92487ca	184	u8_t *msg_ptr;
idinor	0:dcf3c92487ca	185
idinor	0:dcf3c92487ca	186	plen = 0;
idinor	0:dcf3c92487ca	187	while (p != NULL)
idinor	0:dcf3c92487ca	188	{
idinor	0:dcf3c92487ca	189	base = plen;
idinor	0:dcf3c92487ca	190	plen += p->len;
idinor	0:dcf3c92487ca	191	if (ofs < plen)
idinor	0:dcf3c92487ca	192	{
idinor	0:dcf3c92487ca	193	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	194	msg_ptr += ofs - base;
idinor	0:dcf3c92487ca	195	*msg_ptr = type;
idinor	0:dcf3c92487ca	196	return ERR_OK;
idinor	0:dcf3c92487ca	197	}
idinor	0:dcf3c92487ca	198	p = p->next;
idinor	0:dcf3c92487ca	199	}
idinor	0:dcf3c92487ca	200	/* p == NULL, ofs >= plen */
idinor	0:dcf3c92487ca	201	return ERR_ARG;
idinor	0:dcf3c92487ca	202	}
idinor	0:dcf3c92487ca	203
idinor	0:dcf3c92487ca	204	/**
idinor	0:dcf3c92487ca	205	* Encodes host order length field into a pbuf chained ASN1 msg.
idinor	0:dcf3c92487ca	206	*
idinor	0:dcf3c92487ca	207	* @param p points to output pbuf to encode length into
idinor	0:dcf3c92487ca	208	* @param ofs points to the offset within the pbuf chain
idinor	0:dcf3c92487ca	209	* @param length is the host order length to be encoded
idinor	0:dcf3c92487ca	210	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
idinor	0:dcf3c92487ca	211	*/
idinor	0:dcf3c92487ca	212	err_t
idinor	0:dcf3c92487ca	213	snmp_asn1_enc_length(struct pbuf *p, u16_t ofs, u16_t length)
idinor	0:dcf3c92487ca	214	{
idinor	0:dcf3c92487ca	215	u16_t plen, base;
idinor	0:dcf3c92487ca	216	u8_t *msg_ptr;
idinor	0:dcf3c92487ca	217
idinor	0:dcf3c92487ca	218	plen = 0;
idinor	0:dcf3c92487ca	219	while (p != NULL)
idinor	0:dcf3c92487ca	220	{
idinor	0:dcf3c92487ca	221	base = plen;
idinor	0:dcf3c92487ca	222	plen += p->len;
idinor	0:dcf3c92487ca	223	if (ofs < plen)
idinor	0:dcf3c92487ca	224	{
idinor	0:dcf3c92487ca	225	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	226	msg_ptr += ofs - base;
idinor	0:dcf3c92487ca	227
idinor	0:dcf3c92487ca	228	if (length < 0x80)
idinor	0:dcf3c92487ca	229	{
idinor	0:dcf3c92487ca	230	*msg_ptr = (u8_t)length;
idinor	0:dcf3c92487ca	231	return ERR_OK;
idinor	0:dcf3c92487ca	232	}
idinor	0:dcf3c92487ca	233	else if (length < 0x100)
idinor	0:dcf3c92487ca	234	{
idinor	0:dcf3c92487ca	235	*msg_ptr = 0x81;
idinor	0:dcf3c92487ca	236	ofs += 1;
idinor	0:dcf3c92487ca	237	if (ofs >= plen)
idinor	0:dcf3c92487ca	238	{
idinor	0:dcf3c92487ca	239	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	240	p = p->next;
idinor	0:dcf3c92487ca	241	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	242	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	243	}
idinor	0:dcf3c92487ca	244	else
idinor	0:dcf3c92487ca	245	{
idinor	0:dcf3c92487ca	246	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	247	msg_ptr++;
idinor	0:dcf3c92487ca	248	}
idinor	0:dcf3c92487ca	249	*msg_ptr = (u8_t)length;
idinor	0:dcf3c92487ca	250	return ERR_OK;
idinor	0:dcf3c92487ca	251	}
idinor	0:dcf3c92487ca	252	else
idinor	0:dcf3c92487ca	253	{
idinor	0:dcf3c92487ca	254	u8_t i;
idinor	0:dcf3c92487ca	255
idinor	0:dcf3c92487ca	256	/* length >= 0x100 && length <= 0xFFFF */
idinor	0:dcf3c92487ca	257	*msg_ptr = 0x82;
idinor	0:dcf3c92487ca	258	i = 2;
idinor	0:dcf3c92487ca	259	while (i > 0)
idinor	0:dcf3c92487ca	260	{
idinor	0:dcf3c92487ca	261	i--;
idinor	0:dcf3c92487ca	262	ofs += 1;
idinor	0:dcf3c92487ca	263	if (ofs >= plen)
idinor	0:dcf3c92487ca	264	{
idinor	0:dcf3c92487ca	265	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	266	p = p->next;
idinor	0:dcf3c92487ca	267	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	268	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	269	plen += p->len;
idinor	0:dcf3c92487ca	270	}
idinor	0:dcf3c92487ca	271	else
idinor	0:dcf3c92487ca	272	{
idinor	0:dcf3c92487ca	273	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	274	msg_ptr++;
idinor	0:dcf3c92487ca	275	}
idinor	0:dcf3c92487ca	276	if (i == 0)
idinor	0:dcf3c92487ca	277	{
idinor	0:dcf3c92487ca	278	/* least significant length octet */
idinor	0:dcf3c92487ca	279	*msg_ptr = (u8_t)length;
idinor	0:dcf3c92487ca	280	}
idinor	0:dcf3c92487ca	281	else
idinor	0:dcf3c92487ca	282	{
idinor	0:dcf3c92487ca	283	/* most significant length octet */
idinor	0:dcf3c92487ca	284	*msg_ptr = (u8_t)(length >> 8);
idinor	0:dcf3c92487ca	285	}
idinor	0:dcf3c92487ca	286	}
idinor	0:dcf3c92487ca	287	return ERR_OK;
idinor	0:dcf3c92487ca	288	}
idinor	0:dcf3c92487ca	289	}
idinor	0:dcf3c92487ca	290	p = p->next;
idinor	0:dcf3c92487ca	291	}
idinor	0:dcf3c92487ca	292	/* p == NULL, ofs >= plen */
idinor	0:dcf3c92487ca	293	return ERR_ARG;
idinor	0:dcf3c92487ca	294	}
idinor	0:dcf3c92487ca	295
idinor	0:dcf3c92487ca	296	/**
idinor	0:dcf3c92487ca	297	* Encodes u32_t (counter, gauge, timeticks) into a pbuf chained ASN1 msg.
idinor	0:dcf3c92487ca	298	*
idinor	0:dcf3c92487ca	299	* @param p points to output pbuf to encode value into
idinor	0:dcf3c92487ca	300	* @param ofs points to the offset within the pbuf chain
idinor	0:dcf3c92487ca	301	* @param octets_needed encoding length (from snmp_asn1_enc_u32t_cnt())
idinor	0:dcf3c92487ca	302	* @param value is the host order u32_t value to be encoded
idinor	0:dcf3c92487ca	303	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
idinor	0:dcf3c92487ca	304	*
idinor	0:dcf3c92487ca	305	* @see snmp_asn1_enc_u32t_cnt()
idinor	0:dcf3c92487ca	306	*/
idinor	0:dcf3c92487ca	307	err_t
idinor	0:dcf3c92487ca	308	snmp_asn1_enc_u32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, u32_t value)
idinor	0:dcf3c92487ca	309	{
idinor	0:dcf3c92487ca	310	u16_t plen, base;
idinor	0:dcf3c92487ca	311	u8_t *msg_ptr;
idinor	0:dcf3c92487ca	312
idinor	0:dcf3c92487ca	313	plen = 0;
idinor	0:dcf3c92487ca	314	while (p != NULL)
idinor	0:dcf3c92487ca	315	{
idinor	0:dcf3c92487ca	316	base = plen;
idinor	0:dcf3c92487ca	317	plen += p->len;
idinor	0:dcf3c92487ca	318	if (ofs < plen)
idinor	0:dcf3c92487ca	319	{
idinor	0:dcf3c92487ca	320	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	321	msg_ptr += ofs - base;
idinor	0:dcf3c92487ca	322
idinor	0:dcf3c92487ca	323	if (octets_needed == 5)
idinor	0:dcf3c92487ca	324	{
idinor	0:dcf3c92487ca	325	/* not enough bits in 'value' add leading 0x00 */
idinor	0:dcf3c92487ca	326	octets_needed--;
idinor	0:dcf3c92487ca	327	*msg_ptr = 0x00;
idinor	0:dcf3c92487ca	328	ofs += 1;
idinor	0:dcf3c92487ca	329	if (ofs >= plen)
idinor	0:dcf3c92487ca	330	{
idinor	0:dcf3c92487ca	331	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	332	p = p->next;
idinor	0:dcf3c92487ca	333	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	334	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	335	plen += p->len;
idinor	0:dcf3c92487ca	336	}
idinor	0:dcf3c92487ca	337	else
idinor	0:dcf3c92487ca	338	{
idinor	0:dcf3c92487ca	339	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	340	msg_ptr++;
idinor	0:dcf3c92487ca	341	}
idinor	0:dcf3c92487ca	342	}
idinor	0:dcf3c92487ca	343	while (octets_needed > 1)
idinor	0:dcf3c92487ca	344	{
idinor	0:dcf3c92487ca	345	octets_needed--;
idinor	0:dcf3c92487ca	346	*msg_ptr = (u8_t)(value >> (octets_needed << 3));
idinor	0:dcf3c92487ca	347	ofs += 1;
idinor	0:dcf3c92487ca	348	if (ofs >= plen)
idinor	0:dcf3c92487ca	349	{
idinor	0:dcf3c92487ca	350	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	351	p = p->next;
idinor	0:dcf3c92487ca	352	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	353	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	354	plen += p->len;
idinor	0:dcf3c92487ca	355	}
idinor	0:dcf3c92487ca	356	else
idinor	0:dcf3c92487ca	357	{
idinor	0:dcf3c92487ca	358	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	359	msg_ptr++;
idinor	0:dcf3c92487ca	360	}
idinor	0:dcf3c92487ca	361	}
idinor	0:dcf3c92487ca	362	/* (only) one least significant octet */
idinor	0:dcf3c92487ca	363	*msg_ptr = (u8_t)value;
idinor	0:dcf3c92487ca	364	return ERR_OK;
idinor	0:dcf3c92487ca	365	}
idinor	0:dcf3c92487ca	366	p = p->next;
idinor	0:dcf3c92487ca	367	}
idinor	0:dcf3c92487ca	368	/* p == NULL, ofs >= plen */
idinor	0:dcf3c92487ca	369	return ERR_ARG;
idinor	0:dcf3c92487ca	370	}
idinor	0:dcf3c92487ca	371
idinor	0:dcf3c92487ca	372	/**
idinor	0:dcf3c92487ca	373	* Encodes s32_t integer into a pbuf chained ASN1 msg.
idinor	0:dcf3c92487ca	374	*
idinor	0:dcf3c92487ca	375	* @param p points to output pbuf to encode value into
idinor	0:dcf3c92487ca	376	* @param ofs points to the offset within the pbuf chain
idinor	0:dcf3c92487ca	377	* @param octets_needed encoding length (from snmp_asn1_enc_s32t_cnt())
idinor	0:dcf3c92487ca	378	* @param value is the host order s32_t value to be encoded
idinor	0:dcf3c92487ca	379	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
idinor	0:dcf3c92487ca	380	*
idinor	0:dcf3c92487ca	381	* @see snmp_asn1_enc_s32t_cnt()
idinor	0:dcf3c92487ca	382	*/
idinor	0:dcf3c92487ca	383	err_t
idinor	0:dcf3c92487ca	384	snmp_asn1_enc_s32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, s32_t value)
idinor	0:dcf3c92487ca	385	{
idinor	0:dcf3c92487ca	386	u16_t plen, base;
idinor	0:dcf3c92487ca	387	u8_t *msg_ptr;
idinor	0:dcf3c92487ca	388
idinor	0:dcf3c92487ca	389	plen = 0;
idinor	0:dcf3c92487ca	390	while (p != NULL)
idinor	0:dcf3c92487ca	391	{
idinor	0:dcf3c92487ca	392	base = plen;
idinor	0:dcf3c92487ca	393	plen += p->len;
idinor	0:dcf3c92487ca	394	if (ofs < plen)
idinor	0:dcf3c92487ca	395	{
idinor	0:dcf3c92487ca	396	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	397	msg_ptr += ofs - base;
idinor	0:dcf3c92487ca	398
idinor	0:dcf3c92487ca	399	while (octets_needed > 1)
idinor	0:dcf3c92487ca	400	{
idinor	0:dcf3c92487ca	401	octets_needed--;
idinor	0:dcf3c92487ca	402	*msg_ptr = (u8_t)(value >> (octets_needed << 3));
idinor	0:dcf3c92487ca	403	ofs += 1;
idinor	0:dcf3c92487ca	404	if (ofs >= plen)
idinor	0:dcf3c92487ca	405	{
idinor	0:dcf3c92487ca	406	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	407	p = p->next;
idinor	0:dcf3c92487ca	408	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	409	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	410	plen += p->len;
idinor	0:dcf3c92487ca	411	}
idinor	0:dcf3c92487ca	412	else
idinor	0:dcf3c92487ca	413	{
idinor	0:dcf3c92487ca	414	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	415	msg_ptr++;
idinor	0:dcf3c92487ca	416	}
idinor	0:dcf3c92487ca	417	}
idinor	0:dcf3c92487ca	418	/* (only) one least significant octet */
idinor	0:dcf3c92487ca	419	*msg_ptr = (u8_t)value;
idinor	0:dcf3c92487ca	420	return ERR_OK;
idinor	0:dcf3c92487ca	421	}
idinor	0:dcf3c92487ca	422	p = p->next;
idinor	0:dcf3c92487ca	423	}
idinor	0:dcf3c92487ca	424	/* p == NULL, ofs >= plen */
idinor	0:dcf3c92487ca	425	return ERR_ARG;
idinor	0:dcf3c92487ca	426	}
idinor	0:dcf3c92487ca	427
idinor	0:dcf3c92487ca	428	/**
idinor	0:dcf3c92487ca	429	* Encodes object identifier into a pbuf chained ASN1 msg.
idinor	0:dcf3c92487ca	430	*
idinor	0:dcf3c92487ca	431	* @param p points to output pbuf to encode oid into
idinor	0:dcf3c92487ca	432	* @param ofs points to the offset within the pbuf chain
idinor	0:dcf3c92487ca	433	* @param ident_len object identifier array length
idinor	0:dcf3c92487ca	434	* @param ident points to object identifier array
idinor	0:dcf3c92487ca	435	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
idinor	0:dcf3c92487ca	436	*/
idinor	0:dcf3c92487ca	437	err_t
idinor	0:dcf3c92487ca	438	snmp_asn1_enc_oid(struct pbuf p, u16_t ofs, u8_t ident_len, s32_t ident)
idinor	0:dcf3c92487ca	439	{
idinor	0:dcf3c92487ca	440	u16_t plen, base;
idinor	0:dcf3c92487ca	441	u8_t *msg_ptr;
idinor	0:dcf3c92487ca	442
idinor	0:dcf3c92487ca	443	plen = 0;
idinor	0:dcf3c92487ca	444	while (p != NULL)
idinor	0:dcf3c92487ca	445	{
idinor	0:dcf3c92487ca	446	base = plen;
idinor	0:dcf3c92487ca	447	plen += p->len;
idinor	0:dcf3c92487ca	448	if (ofs < plen)
idinor	0:dcf3c92487ca	449	{
idinor	0:dcf3c92487ca	450	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	451	msg_ptr += ofs - base;
idinor	0:dcf3c92487ca	452
idinor	0:dcf3c92487ca	453	if (ident_len > 1)
idinor	0:dcf3c92487ca	454	{
idinor	0:dcf3c92487ca	455	if ((ident[0] == 1) && (ident[1] == 3))
idinor	0:dcf3c92487ca	456	{
idinor	0:dcf3c92487ca	457	/* compressed (most common) prefix .iso.org */
idinor	0:dcf3c92487ca	458	*msg_ptr = 0x2b;
idinor	0:dcf3c92487ca	459	}
idinor	0:dcf3c92487ca	460	else
idinor	0:dcf3c92487ca	461	{
idinor	0:dcf3c92487ca	462	/* calculate prefix */
idinor	0:dcf3c92487ca	463	msg_ptr = (u8_t)((ident[0] 40) + ident[1]);
idinor	0:dcf3c92487ca	464	}
idinor	0:dcf3c92487ca	465	ofs += 1;
idinor	0:dcf3c92487ca	466	if (ofs >= plen)
idinor	0:dcf3c92487ca	467	{
idinor	0:dcf3c92487ca	468	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	469	p = p->next;
idinor	0:dcf3c92487ca	470	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	471	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	472	plen += p->len;
idinor	0:dcf3c92487ca	473	}
idinor	0:dcf3c92487ca	474	else
idinor	0:dcf3c92487ca	475	{
idinor	0:dcf3c92487ca	476	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	477	msg_ptr++;
idinor	0:dcf3c92487ca	478	}
idinor	0:dcf3c92487ca	479	ident_len -= 2;
idinor	0:dcf3c92487ca	480	ident += 2;
idinor	0:dcf3c92487ca	481	}
idinor	0:dcf3c92487ca	482	else
idinor	0:dcf3c92487ca	483	{
idinor	0:dcf3c92487ca	484	/* @bug: allow empty varbinds for symmetry (we must decode them for getnext), allow partial compression?? */
idinor	0:dcf3c92487ca	485	/* ident_len <= 1, at least we need zeroDotZero (0.0) (ident_len == 2) */
idinor	0:dcf3c92487ca	486	return ERR_ARG;
idinor	0:dcf3c92487ca	487	}
idinor	0:dcf3c92487ca	488	while (ident_len > 0)
idinor	0:dcf3c92487ca	489	{
idinor	0:dcf3c92487ca	490	s32_t sub_id;
idinor	0:dcf3c92487ca	491	u8_t shift, tail;
idinor	0:dcf3c92487ca	492
idinor	0:dcf3c92487ca	493	ident_len--;
idinor	0:dcf3c92487ca	494	sub_id = *ident;
idinor	0:dcf3c92487ca	495	tail = 0;
idinor	0:dcf3c92487ca	496	shift = 28;
idinor	0:dcf3c92487ca	497	while(shift > 0)
idinor	0:dcf3c92487ca	498	{
idinor	0:dcf3c92487ca	499	u8_t code;
idinor	0:dcf3c92487ca	500
idinor	0:dcf3c92487ca	501	code = (u8_t)(sub_id >> shift);
idinor	0:dcf3c92487ca	502	if ((code != 0) \|\| (tail != 0))
idinor	0:dcf3c92487ca	503	{
idinor	0:dcf3c92487ca	504	tail = 1;
idinor	0:dcf3c92487ca	505	*msg_ptr = code \| 0x80;
idinor	0:dcf3c92487ca	506	ofs += 1;
idinor	0:dcf3c92487ca	507	if (ofs >= plen)
idinor	0:dcf3c92487ca	508	{
idinor	0:dcf3c92487ca	509	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	510	p = p->next;
idinor	0:dcf3c92487ca	511	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	512	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	513	plen += p->len;
idinor	0:dcf3c92487ca	514	}
idinor	0:dcf3c92487ca	515	else
idinor	0:dcf3c92487ca	516	{
idinor	0:dcf3c92487ca	517	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	518	msg_ptr++;
idinor	0:dcf3c92487ca	519	}
idinor	0:dcf3c92487ca	520	}
idinor	0:dcf3c92487ca	521	shift -= 7;
idinor	0:dcf3c92487ca	522	}
idinor	0:dcf3c92487ca	523	*msg_ptr = (u8_t)sub_id & 0x7F;
idinor	0:dcf3c92487ca	524	if (ident_len > 0)
idinor	0:dcf3c92487ca	525	{
idinor	0:dcf3c92487ca	526	ofs += 1;
idinor	0:dcf3c92487ca	527	if (ofs >= plen)
idinor	0:dcf3c92487ca	528	{
idinor	0:dcf3c92487ca	529	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	530	p = p->next;
idinor	0:dcf3c92487ca	531	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	532	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	533	plen += p->len;
idinor	0:dcf3c92487ca	534	}
idinor	0:dcf3c92487ca	535	else
idinor	0:dcf3c92487ca	536	{
idinor	0:dcf3c92487ca	537	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	538	msg_ptr++;
idinor	0:dcf3c92487ca	539	}
idinor	0:dcf3c92487ca	540	}
idinor	0:dcf3c92487ca	541	/* proceed to next sub-identifier */
idinor	0:dcf3c92487ca	542	ident++;
idinor	0:dcf3c92487ca	543	}
idinor	0:dcf3c92487ca	544	return ERR_OK;
idinor	0:dcf3c92487ca	545	}
idinor	0:dcf3c92487ca	546	p = p->next;
idinor	0:dcf3c92487ca	547	}
idinor	0:dcf3c92487ca	548	/* p == NULL, ofs >= plen */
idinor	0:dcf3c92487ca	549	return ERR_ARG;
idinor	0:dcf3c92487ca	550	}
idinor	0:dcf3c92487ca	551
idinor	0:dcf3c92487ca	552	/**
idinor	0:dcf3c92487ca	553	* Encodes raw data (octet string, opaque) into a pbuf chained ASN1 msg.
idinor	0:dcf3c92487ca	554	*
idinor	0:dcf3c92487ca	555	* @param p points to output pbuf to encode raw data into
idinor	0:dcf3c92487ca	556	* @param ofs points to the offset within the pbuf chain
idinor	0:dcf3c92487ca	557	* @param raw_len raw data length
idinor	0:dcf3c92487ca	558	* @param raw points raw data
idinor	0:dcf3c92487ca	559	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
idinor	0:dcf3c92487ca	560	*/
idinor	0:dcf3c92487ca	561	err_t
idinor	0:dcf3c92487ca	562	snmp_asn1_enc_raw(struct pbuf p, u16_t ofs, u16_t raw_len, u8_t raw)
idinor	0:dcf3c92487ca	563	{
idinor	0:dcf3c92487ca	564	u16_t plen, base;
idinor	0:dcf3c92487ca	565	u8_t *msg_ptr;
idinor	0:dcf3c92487ca	566
idinor	0:dcf3c92487ca	567	plen = 0;
idinor	0:dcf3c92487ca	568	while (p != NULL)
idinor	0:dcf3c92487ca	569	{
idinor	0:dcf3c92487ca	570	base = plen;
idinor	0:dcf3c92487ca	571	plen += p->len;
idinor	0:dcf3c92487ca	572	if (ofs < plen)
idinor	0:dcf3c92487ca	573	{
idinor	0:dcf3c92487ca	574	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	575	msg_ptr += ofs - base;
idinor	0:dcf3c92487ca	576
idinor	0:dcf3c92487ca	577	while (raw_len > 1)
idinor	0:dcf3c92487ca	578	{
idinor	0:dcf3c92487ca	579	/* copy raw_len - 1 octets */
idinor	0:dcf3c92487ca	580	raw_len--;
idinor	0:dcf3c92487ca	581	msg_ptr = raw;
idinor	0:dcf3c92487ca	582	raw++;
idinor	0:dcf3c92487ca	583	ofs += 1;
idinor	0:dcf3c92487ca	584	if (ofs >= plen)
idinor	0:dcf3c92487ca	585	{
idinor	0:dcf3c92487ca	586	/* next octet in next pbuf */
idinor	0:dcf3c92487ca	587	p = p->next;
idinor	0:dcf3c92487ca	588	if (p == NULL) { return ERR_ARG; }
idinor	0:dcf3c92487ca	589	msg_ptr = (u8_t*)p->payload;
idinor	0:dcf3c92487ca	590	plen += p->len;
idinor	0:dcf3c92487ca	591	}
idinor	0:dcf3c92487ca	592	else
idinor	0:dcf3c92487ca	593	{
idinor	0:dcf3c92487ca	594	/* next octet in same pbuf */
idinor	0:dcf3c92487ca	595	msg_ptr++;
idinor	0:dcf3c92487ca	596	}
idinor	0:dcf3c92487ca	597	}
idinor	0:dcf3c92487ca	598	if (raw_len > 0)
idinor	0:dcf3c92487ca	599	{
idinor	0:dcf3c92487ca	600	/* copy last or single octet */
idinor	0:dcf3c92487ca	601	msg_ptr = raw;
idinor	0:dcf3c92487ca	602	}
idinor	0:dcf3c92487ca	603	return ERR_OK;
idinor	0:dcf3c92487ca	604	}
idinor	0:dcf3c92487ca	605	p = p->next;
idinor	0:dcf3c92487ca	606	}
idinor	0:dcf3c92487ca	607	/* p == NULL, ofs >= plen */
idinor	0:dcf3c92487ca	608	return ERR_ARG;
idinor	0:dcf3c92487ca	609	}
idinor	0:dcf3c92487ca	610
idinor	0:dcf3c92487ca	611	#endif /* LWIP_SNMP */

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Type:	Library
Created:	20 Jul 2011
Imports:	35
Forks:	0
Commits:	1
Dependents:	1
Dependencies:	0
Followers:	1

lwip/core/snmp/asn1_enc.c@0:dcf3c92487ca, 2011-07-20 (annotated)

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