WebSockets2 - Embedded WebSockets Experiment

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Embedded WebSockets Experiment

Core/lwIP/core/snmp/asn1_dec.c@0:6dee052a3fa4, 2011-07-26 (annotated)

Committer:: nandgate
Date:: Tue Jul 26 05:30:53 2011 +0000
Revision:: 0:6dee052a3fa4

Who changed what in which revision?

User	Revision	Line number	New contents of line
nandgate	0:6dee052a3fa4	1	/**
nandgate	0:6dee052a3fa4	2	* @file
nandgate	0:6dee052a3fa4	3	* Abstract Syntax Notation One (ISO 8824, 8825) decoding
nandgate	0:6dee052a3fa4	4	*
nandgate	0:6dee052a3fa4	5	* @todo not optimised (yet), favor correctness over speed, favor speed over size
nandgate	0:6dee052a3fa4	6	*/
nandgate	0:6dee052a3fa4	7
nandgate	0:6dee052a3fa4	8	/*
nandgate	0:6dee052a3fa4	9	* Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
nandgate	0:6dee052a3fa4	10	* All rights reserved.
nandgate	0:6dee052a3fa4	11	*
nandgate	0:6dee052a3fa4	12	* Redistribution and use in source and binary forms, with or without modification,
nandgate	0:6dee052a3fa4	13	* are permitted provided that the following conditions are met:
nandgate	0:6dee052a3fa4	14	*
nandgate	0:6dee052a3fa4	15	* 1. Redistributions of source code must retain the above copyright notice,
nandgate	0:6dee052a3fa4	16	* this list of conditions and the following disclaimer.
nandgate	0:6dee052a3fa4	17	* 2. Redistributions in binary form must reproduce the above copyright notice,
nandgate	0:6dee052a3fa4	18	* this list of conditions and the following disclaimer in the documentation
nandgate	0:6dee052a3fa4	19	* and/or other materials provided with the distribution.
nandgate	0:6dee052a3fa4	20	* 3. The name of the author may not be used to endorse or promote products
nandgate	0:6dee052a3fa4	21	* derived from this software without specific prior written permission.
nandgate	0:6dee052a3fa4	22	*
nandgate	0:6dee052a3fa4	23	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
nandgate	0:6dee052a3fa4	24	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
nandgate	0:6dee052a3fa4	25	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
nandgate	0:6dee052a3fa4	26	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
nandgate	0:6dee052a3fa4	27	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
nandgate	0:6dee052a3fa4	28	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
nandgate	0:6dee052a3fa4	29	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
nandgate	0:6dee052a3fa4	30	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
nandgate	0:6dee052a3fa4	31	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
nandgate	0:6dee052a3fa4	32	* OF SUCH DAMAGE.
nandgate	0:6dee052a3fa4	33	*
nandgate	0:6dee052a3fa4	34	* Author: Christiaan Simons <christiaan.simons@axon.tv>
nandgate	0:6dee052a3fa4	35	*/
nandgate	0:6dee052a3fa4	36
nandgate	0:6dee052a3fa4	37	#include "lwip/opt.h"
nandgate	0:6dee052a3fa4	38
nandgate	0:6dee052a3fa4	39	#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
nandgate	0:6dee052a3fa4	40
nandgate	0:6dee052a3fa4	41	#include "lwip/snmp_asn1.h"
nandgate	0:6dee052a3fa4	42
nandgate	0:6dee052a3fa4	43	/**
nandgate	0:6dee052a3fa4	44	* Retrieves type field from incoming pbuf chain.
nandgate	0:6dee052a3fa4	45	*
nandgate	0:6dee052a3fa4	46	* @param p points to a pbuf holding an ASN1 coded type field
nandgate	0:6dee052a3fa4	47	* @param ofs points to the offset within the pbuf chain of the ASN1 coded type field
nandgate	0:6dee052a3fa4	48	* @param type return ASN1 type
nandgate	0:6dee052a3fa4	49	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
nandgate	0:6dee052a3fa4	50	*/
nandgate	0:6dee052a3fa4	51	err_t
nandgate	0:6dee052a3fa4	52	snmp_asn1_dec_type(struct pbuf p, u16_t ofs, u8_t type)
nandgate	0:6dee052a3fa4	53	{
nandgate	0:6dee052a3fa4	54	u16_t plen, base;
nandgate	0:6dee052a3fa4	55	u8_t *msg_ptr;
nandgate	0:6dee052a3fa4	56
nandgate	0:6dee052a3fa4	57	plen = 0;
nandgate	0:6dee052a3fa4	58	while (p != NULL)
nandgate	0:6dee052a3fa4	59	{
nandgate	0:6dee052a3fa4	60	base = plen;
nandgate	0:6dee052a3fa4	61	plen += p->len;
nandgate	0:6dee052a3fa4	62	if (ofs < plen)
nandgate	0:6dee052a3fa4	63	{
nandgate	0:6dee052a3fa4	64	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	65	msg_ptr += ofs - base;
nandgate	0:6dee052a3fa4	66	type = msg_ptr;
nandgate	0:6dee052a3fa4	67	return ERR_OK;
nandgate	0:6dee052a3fa4	68	}
nandgate	0:6dee052a3fa4	69	p = p->next;
nandgate	0:6dee052a3fa4	70	}
nandgate	0:6dee052a3fa4	71	/* p == NULL, ofs >= plen */
nandgate	0:6dee052a3fa4	72	return ERR_ARG;
nandgate	0:6dee052a3fa4	73	}
nandgate	0:6dee052a3fa4	74
nandgate	0:6dee052a3fa4	75	/**
nandgate	0:6dee052a3fa4	76	* Decodes length field from incoming pbuf chain into host length.
nandgate	0:6dee052a3fa4	77	*
nandgate	0:6dee052a3fa4	78	* @param p points to a pbuf holding an ASN1 coded length
nandgate	0:6dee052a3fa4	79	* @param ofs points to the offset within the pbuf chain of the ASN1 coded length
nandgate	0:6dee052a3fa4	80	* @param octets_used returns number of octets used by the length code
nandgate	0:6dee052a3fa4	81	* @param length return host order length, upto 64k
nandgate	0:6dee052a3fa4	82	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
nandgate	0:6dee052a3fa4	83	*/
nandgate	0:6dee052a3fa4	84	err_t
nandgate	0:6dee052a3fa4	85	snmp_asn1_dec_length(struct pbuf p, u16_t ofs, u8_t octets_used, u16_t *length)
nandgate	0:6dee052a3fa4	86	{
nandgate	0:6dee052a3fa4	87	u16_t plen, base;
nandgate	0:6dee052a3fa4	88	u8_t *msg_ptr;
nandgate	0:6dee052a3fa4	89
nandgate	0:6dee052a3fa4	90	plen = 0;
nandgate	0:6dee052a3fa4	91	while (p != NULL)
nandgate	0:6dee052a3fa4	92	{
nandgate	0:6dee052a3fa4	93	base = plen;
nandgate	0:6dee052a3fa4	94	plen += p->len;
nandgate	0:6dee052a3fa4	95	if (ofs < plen)
nandgate	0:6dee052a3fa4	96	{
nandgate	0:6dee052a3fa4	97	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	98	msg_ptr += ofs - base;
nandgate	0:6dee052a3fa4	99
nandgate	0:6dee052a3fa4	100	if (*msg_ptr < 0x80)
nandgate	0:6dee052a3fa4	101	{
nandgate	0:6dee052a3fa4	102	/* primitive definite length format */
nandgate	0:6dee052a3fa4	103	*octets_used = 1;
nandgate	0:6dee052a3fa4	104	length = msg_ptr;
nandgate	0:6dee052a3fa4	105	return ERR_OK;
nandgate	0:6dee052a3fa4	106	}
nandgate	0:6dee052a3fa4	107	else if (*msg_ptr == 0x80)
nandgate	0:6dee052a3fa4	108	{
nandgate	0:6dee052a3fa4	109	/* constructed indefinite length format, termination with two zero octets */
nandgate	0:6dee052a3fa4	110	u8_t zeros;
nandgate	0:6dee052a3fa4	111	u8_t i;
nandgate	0:6dee052a3fa4	112
nandgate	0:6dee052a3fa4	113	*length = 0;
nandgate	0:6dee052a3fa4	114	zeros = 0;
nandgate	0:6dee052a3fa4	115	while (zeros != 2)
nandgate	0:6dee052a3fa4	116	{
nandgate	0:6dee052a3fa4	117	i = 2;
nandgate	0:6dee052a3fa4	118	while (i > 0)
nandgate	0:6dee052a3fa4	119	{
nandgate	0:6dee052a3fa4	120	i--;
nandgate	0:6dee052a3fa4	121	(*length) += 1;
nandgate	0:6dee052a3fa4	122	ofs += 1;
nandgate	0:6dee052a3fa4	123	if (ofs >= plen)
nandgate	0:6dee052a3fa4	124	{
nandgate	0:6dee052a3fa4	125	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	126	p = p->next;
nandgate	0:6dee052a3fa4	127	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	128	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	129	plen += p->len;
nandgate	0:6dee052a3fa4	130	}
nandgate	0:6dee052a3fa4	131	else
nandgate	0:6dee052a3fa4	132	{
nandgate	0:6dee052a3fa4	133	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	134	msg_ptr++;
nandgate	0:6dee052a3fa4	135	}
nandgate	0:6dee052a3fa4	136	if (*msg_ptr == 0)
nandgate	0:6dee052a3fa4	137	{
nandgate	0:6dee052a3fa4	138	zeros++;
nandgate	0:6dee052a3fa4	139	if (zeros == 2)
nandgate	0:6dee052a3fa4	140	{
nandgate	0:6dee052a3fa4	141	/* stop while (i > 0) */
nandgate	0:6dee052a3fa4	142	i = 0;
nandgate	0:6dee052a3fa4	143	}
nandgate	0:6dee052a3fa4	144	}
nandgate	0:6dee052a3fa4	145	else
nandgate	0:6dee052a3fa4	146	{
nandgate	0:6dee052a3fa4	147	zeros = 0;
nandgate	0:6dee052a3fa4	148	}
nandgate	0:6dee052a3fa4	149	}
nandgate	0:6dee052a3fa4	150	}
nandgate	0:6dee052a3fa4	151	*octets_used = 1;
nandgate	0:6dee052a3fa4	152	return ERR_OK;
nandgate	0:6dee052a3fa4	153	}
nandgate	0:6dee052a3fa4	154	else if (*msg_ptr == 0x81)
nandgate	0:6dee052a3fa4	155	{
nandgate	0:6dee052a3fa4	156	/* constructed definite length format, one octet */
nandgate	0:6dee052a3fa4	157	ofs += 1;
nandgate	0:6dee052a3fa4	158	if (ofs >= plen)
nandgate	0:6dee052a3fa4	159	{
nandgate	0:6dee052a3fa4	160	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	161	p = p->next;
nandgate	0:6dee052a3fa4	162	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	163	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	164	}
nandgate	0:6dee052a3fa4	165	else
nandgate	0:6dee052a3fa4	166	{
nandgate	0:6dee052a3fa4	167	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	168	msg_ptr++;
nandgate	0:6dee052a3fa4	169	}
nandgate	0:6dee052a3fa4	170	length = msg_ptr;
nandgate	0:6dee052a3fa4	171	*octets_used = 2;
nandgate	0:6dee052a3fa4	172	return ERR_OK;
nandgate	0:6dee052a3fa4	173	}
nandgate	0:6dee052a3fa4	174	else if (*msg_ptr == 0x82)
nandgate	0:6dee052a3fa4	175	{
nandgate	0:6dee052a3fa4	176	u8_t i;
nandgate	0:6dee052a3fa4	177
nandgate	0:6dee052a3fa4	178	/* constructed definite length format, two octets */
nandgate	0:6dee052a3fa4	179	i = 2;
nandgate	0:6dee052a3fa4	180	while (i > 0)
nandgate	0:6dee052a3fa4	181	{
nandgate	0:6dee052a3fa4	182	i--;
nandgate	0:6dee052a3fa4	183	ofs += 1;
nandgate	0:6dee052a3fa4	184	if (ofs >= plen)
nandgate	0:6dee052a3fa4	185	{
nandgate	0:6dee052a3fa4	186	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	187	p = p->next;
nandgate	0:6dee052a3fa4	188	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	189	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	190	plen += p->len;
nandgate	0:6dee052a3fa4	191	}
nandgate	0:6dee052a3fa4	192	else
nandgate	0:6dee052a3fa4	193	{
nandgate	0:6dee052a3fa4	194	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	195	msg_ptr++;
nandgate	0:6dee052a3fa4	196	}
nandgate	0:6dee052a3fa4	197	if (i == 0)
nandgate	0:6dee052a3fa4	198	{
nandgate	0:6dee052a3fa4	199	/* least significant length octet */
nandgate	0:6dee052a3fa4	200	length \|= msg_ptr;
nandgate	0:6dee052a3fa4	201	}
nandgate	0:6dee052a3fa4	202	else
nandgate	0:6dee052a3fa4	203	{
nandgate	0:6dee052a3fa4	204	/* most significant length octet */
nandgate	0:6dee052a3fa4	205	length = (msg_ptr) << 8;
nandgate	0:6dee052a3fa4	206	}
nandgate	0:6dee052a3fa4	207	}
nandgate	0:6dee052a3fa4	208	*octets_used = 3;
nandgate	0:6dee052a3fa4	209	return ERR_OK;
nandgate	0:6dee052a3fa4	210	}
nandgate	0:6dee052a3fa4	211	else
nandgate	0:6dee052a3fa4	212	{
nandgate	0:6dee052a3fa4	213	/* constructed definite length format 3..127 octets, this is too big (>64k) */
nandgate	0:6dee052a3fa4	214	/** @todo: do we need to accept inefficient codings with many leading zero's? */
nandgate	0:6dee052a3fa4	215	octets_used = 1 + ((msg_ptr) & 0x7f);
nandgate	0:6dee052a3fa4	216	return ERR_ARG;
nandgate	0:6dee052a3fa4	217	}
nandgate	0:6dee052a3fa4	218	}
nandgate	0:6dee052a3fa4	219	p = p->next;
nandgate	0:6dee052a3fa4	220	}
nandgate	0:6dee052a3fa4	221
nandgate	0:6dee052a3fa4	222	/* p == NULL, ofs >= plen */
nandgate	0:6dee052a3fa4	223	return ERR_ARG;
nandgate	0:6dee052a3fa4	224	}
nandgate	0:6dee052a3fa4	225
nandgate	0:6dee052a3fa4	226	/**
nandgate	0:6dee052a3fa4	227	* Decodes positive integer (counter, gauge, timeticks) into u32_t.
nandgate	0:6dee052a3fa4	228	*
nandgate	0:6dee052a3fa4	229	* @param p points to a pbuf holding an ASN1 coded integer
nandgate	0:6dee052a3fa4	230	* @param ofs points to the offset within the pbuf chain of the ASN1 coded integer
nandgate	0:6dee052a3fa4	231	* @param len length of the coded integer field
nandgate	0:6dee052a3fa4	232	* @param value return host order integer
nandgate	0:6dee052a3fa4	233	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
nandgate	0:6dee052a3fa4	234	*
nandgate	0:6dee052a3fa4	235	* @note ASN coded integers are _always_ signed. E.g. +0xFFFF is coded
nandgate	0:6dee052a3fa4	236	* as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value
nandgate	0:6dee052a3fa4	237	* of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!!
nandgate	0:6dee052a3fa4	238	*/
nandgate	0:6dee052a3fa4	239	err_t
nandgate	0:6dee052a3fa4	240	snmp_asn1_dec_u32t(struct pbuf p, u16_t ofs, u16_t len, u32_t value)
nandgate	0:6dee052a3fa4	241	{
nandgate	0:6dee052a3fa4	242	u16_t plen, base;
nandgate	0:6dee052a3fa4	243	u8_t *msg_ptr;
nandgate	0:6dee052a3fa4	244
nandgate	0:6dee052a3fa4	245	plen = 0;
nandgate	0:6dee052a3fa4	246	while (p != NULL)
nandgate	0:6dee052a3fa4	247	{
nandgate	0:6dee052a3fa4	248	base = plen;
nandgate	0:6dee052a3fa4	249	plen += p->len;
nandgate	0:6dee052a3fa4	250	if (ofs < plen)
nandgate	0:6dee052a3fa4	251	{
nandgate	0:6dee052a3fa4	252	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	253	msg_ptr += ofs - base;
nandgate	0:6dee052a3fa4	254	if ((len > 0) && (len < 6))
nandgate	0:6dee052a3fa4	255	{
nandgate	0:6dee052a3fa4	256	/* start from zero */
nandgate	0:6dee052a3fa4	257	*value = 0;
nandgate	0:6dee052a3fa4	258	if (*msg_ptr & 0x80)
nandgate	0:6dee052a3fa4	259	{
nandgate	0:6dee052a3fa4	260	/* negative, expecting zero sign bit! */
nandgate	0:6dee052a3fa4	261	return ERR_ARG;
nandgate	0:6dee052a3fa4	262	}
nandgate	0:6dee052a3fa4	263	else
nandgate	0:6dee052a3fa4	264	{
nandgate	0:6dee052a3fa4	265	/* positive */
nandgate	0:6dee052a3fa4	266	if ((len > 1) && (*msg_ptr == 0))
nandgate	0:6dee052a3fa4	267	{
nandgate	0:6dee052a3fa4	268	/* skip leading "sign byte" octet 0x00 */
nandgate	0:6dee052a3fa4	269	len--;
nandgate	0:6dee052a3fa4	270	ofs += 1;
nandgate	0:6dee052a3fa4	271	if (ofs >= plen)
nandgate	0:6dee052a3fa4	272	{
nandgate	0:6dee052a3fa4	273	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	274	p = p->next;
nandgate	0:6dee052a3fa4	275	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	276	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	277	plen += p->len;
nandgate	0:6dee052a3fa4	278	}
nandgate	0:6dee052a3fa4	279	else
nandgate	0:6dee052a3fa4	280	{
nandgate	0:6dee052a3fa4	281	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	282	msg_ptr++;
nandgate	0:6dee052a3fa4	283	}
nandgate	0:6dee052a3fa4	284	}
nandgate	0:6dee052a3fa4	285	}
nandgate	0:6dee052a3fa4	286	/* OR octets with value */
nandgate	0:6dee052a3fa4	287	while (len > 1)
nandgate	0:6dee052a3fa4	288	{
nandgate	0:6dee052a3fa4	289	len--;
nandgate	0:6dee052a3fa4	290	value \|= msg_ptr;
nandgate	0:6dee052a3fa4	291	*value <<= 8;
nandgate	0:6dee052a3fa4	292	ofs += 1;
nandgate	0:6dee052a3fa4	293	if (ofs >= plen)
nandgate	0:6dee052a3fa4	294	{
nandgate	0:6dee052a3fa4	295	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	296	p = p->next;
nandgate	0:6dee052a3fa4	297	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	298	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	299	plen += p->len;
nandgate	0:6dee052a3fa4	300	}
nandgate	0:6dee052a3fa4	301	else
nandgate	0:6dee052a3fa4	302	{
nandgate	0:6dee052a3fa4	303	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	304	msg_ptr++;
nandgate	0:6dee052a3fa4	305	}
nandgate	0:6dee052a3fa4	306	}
nandgate	0:6dee052a3fa4	307	value \|= msg_ptr;
nandgate	0:6dee052a3fa4	308	return ERR_OK;
nandgate	0:6dee052a3fa4	309	}
nandgate	0:6dee052a3fa4	310	else
nandgate	0:6dee052a3fa4	311	{
nandgate	0:6dee052a3fa4	312	return ERR_ARG;
nandgate	0:6dee052a3fa4	313	}
nandgate	0:6dee052a3fa4	314	}
nandgate	0:6dee052a3fa4	315	p = p->next;
nandgate	0:6dee052a3fa4	316	}
nandgate	0:6dee052a3fa4	317	/* p == NULL, ofs >= plen */
nandgate	0:6dee052a3fa4	318	return ERR_ARG;
nandgate	0:6dee052a3fa4	319	}
nandgate	0:6dee052a3fa4	320
nandgate	0:6dee052a3fa4	321	/**
nandgate	0:6dee052a3fa4	322	* Decodes integer into s32_t.
nandgate	0:6dee052a3fa4	323	*
nandgate	0:6dee052a3fa4	324	* @param p points to a pbuf holding an ASN1 coded integer
nandgate	0:6dee052a3fa4	325	* @param ofs points to the offset within the pbuf chain of the ASN1 coded integer
nandgate	0:6dee052a3fa4	326	* @param len length of the coded integer field
nandgate	0:6dee052a3fa4	327	* @param value return host order integer
nandgate	0:6dee052a3fa4	328	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
nandgate	0:6dee052a3fa4	329	*
nandgate	0:6dee052a3fa4	330	* @note ASN coded integers are _always_ signed!
nandgate	0:6dee052a3fa4	331	*/
nandgate	0:6dee052a3fa4	332	err_t
nandgate	0:6dee052a3fa4	333	snmp_asn1_dec_s32t(struct pbuf p, u16_t ofs, u16_t len, s32_t value)
nandgate	0:6dee052a3fa4	334	{
nandgate	0:6dee052a3fa4	335	u16_t plen, base;
nandgate	0:6dee052a3fa4	336	u8_t *msg_ptr;
nandgate	0:6dee052a3fa4	337	#if BYTE_ORDER == LITTLE_ENDIAN
nandgate	0:6dee052a3fa4	338	u8_t lsb_ptr = (u8_t)value;
nandgate	0:6dee052a3fa4	339	#endif
nandgate	0:6dee052a3fa4	340	#if BYTE_ORDER == BIG_ENDIAN
nandgate	0:6dee052a3fa4	341	u8_t lsb_ptr = (u8_t)value + sizeof(s32_t) - 1;
nandgate	0:6dee052a3fa4	342	#endif
nandgate	0:6dee052a3fa4	343	u8_t sign;
nandgate	0:6dee052a3fa4	344
nandgate	0:6dee052a3fa4	345	plen = 0;
nandgate	0:6dee052a3fa4	346	while (p != NULL)
nandgate	0:6dee052a3fa4	347	{
nandgate	0:6dee052a3fa4	348	base = plen;
nandgate	0:6dee052a3fa4	349	plen += p->len;
nandgate	0:6dee052a3fa4	350	if (ofs < plen)
nandgate	0:6dee052a3fa4	351	{
nandgate	0:6dee052a3fa4	352	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	353	msg_ptr += ofs - base;
nandgate	0:6dee052a3fa4	354	if ((len > 0) && (len < 5))
nandgate	0:6dee052a3fa4	355	{
nandgate	0:6dee052a3fa4	356	if (*msg_ptr & 0x80)
nandgate	0:6dee052a3fa4	357	{
nandgate	0:6dee052a3fa4	358	/* negative, start from -1 */
nandgate	0:6dee052a3fa4	359	*value = -1;
nandgate	0:6dee052a3fa4	360	sign = 1;
nandgate	0:6dee052a3fa4	361	}
nandgate	0:6dee052a3fa4	362	else
nandgate	0:6dee052a3fa4	363	{
nandgate	0:6dee052a3fa4	364	/* positive, start from 0 */
nandgate	0:6dee052a3fa4	365	*value = 0;
nandgate	0:6dee052a3fa4	366	sign = 0;
nandgate	0:6dee052a3fa4	367	}
nandgate	0:6dee052a3fa4	368	/* OR/AND octets with value */
nandgate	0:6dee052a3fa4	369	while (len > 1)
nandgate	0:6dee052a3fa4	370	{
nandgate	0:6dee052a3fa4	371	len--;
nandgate	0:6dee052a3fa4	372	if (sign)
nandgate	0:6dee052a3fa4	373	{
nandgate	0:6dee052a3fa4	374	lsb_ptr &= msg_ptr;
nandgate	0:6dee052a3fa4	375	*value <<= 8;
nandgate	0:6dee052a3fa4	376	*lsb_ptr \|= 255;
nandgate	0:6dee052a3fa4	377	}
nandgate	0:6dee052a3fa4	378	else
nandgate	0:6dee052a3fa4	379	{
nandgate	0:6dee052a3fa4	380	lsb_ptr \|= msg_ptr;
nandgate	0:6dee052a3fa4	381	*value <<= 8;
nandgate	0:6dee052a3fa4	382	}
nandgate	0:6dee052a3fa4	383	ofs += 1;
nandgate	0:6dee052a3fa4	384	if (ofs >= plen)
nandgate	0:6dee052a3fa4	385	{
nandgate	0:6dee052a3fa4	386	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	387	p = p->next;
nandgate	0:6dee052a3fa4	388	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	389	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	390	plen += p->len;
nandgate	0:6dee052a3fa4	391	}
nandgate	0:6dee052a3fa4	392	else
nandgate	0:6dee052a3fa4	393	{
nandgate	0:6dee052a3fa4	394	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	395	msg_ptr++;
nandgate	0:6dee052a3fa4	396	}
nandgate	0:6dee052a3fa4	397	}
nandgate	0:6dee052a3fa4	398	if (sign)
nandgate	0:6dee052a3fa4	399	{
nandgate	0:6dee052a3fa4	400	lsb_ptr &= msg_ptr;
nandgate	0:6dee052a3fa4	401	}
nandgate	0:6dee052a3fa4	402	else
nandgate	0:6dee052a3fa4	403	{
nandgate	0:6dee052a3fa4	404	lsb_ptr \|= msg_ptr;
nandgate	0:6dee052a3fa4	405	}
nandgate	0:6dee052a3fa4	406	return ERR_OK;
nandgate	0:6dee052a3fa4	407	}
nandgate	0:6dee052a3fa4	408	else
nandgate	0:6dee052a3fa4	409	{
nandgate	0:6dee052a3fa4	410	return ERR_ARG;
nandgate	0:6dee052a3fa4	411	}
nandgate	0:6dee052a3fa4	412	}
nandgate	0:6dee052a3fa4	413	p = p->next;
nandgate	0:6dee052a3fa4	414	}
nandgate	0:6dee052a3fa4	415	/* p == NULL, ofs >= plen */
nandgate	0:6dee052a3fa4	416	return ERR_ARG;
nandgate	0:6dee052a3fa4	417	}
nandgate	0:6dee052a3fa4	418
nandgate	0:6dee052a3fa4	419	/**
nandgate	0:6dee052a3fa4	420	* Decodes object identifier from incoming message into array of s32_t.
nandgate	0:6dee052a3fa4	421	*
nandgate	0:6dee052a3fa4	422	* @param p points to a pbuf holding an ASN1 coded object identifier
nandgate	0:6dee052a3fa4	423	* @param ofs points to the offset within the pbuf chain of the ASN1 coded object identifier
nandgate	0:6dee052a3fa4	424	* @param len length of the coded object identifier
nandgate	0:6dee052a3fa4	425	* @param oid return object identifier struct
nandgate	0:6dee052a3fa4	426	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
nandgate	0:6dee052a3fa4	427	*/
nandgate	0:6dee052a3fa4	428	err_t
nandgate	0:6dee052a3fa4	429	snmp_asn1_dec_oid(struct pbuf p, u16_t ofs, u16_t len, struct snmp_obj_id oid)
nandgate	0:6dee052a3fa4	430	{
nandgate	0:6dee052a3fa4	431	u16_t plen, base;
nandgate	0:6dee052a3fa4	432	u8_t *msg_ptr;
nandgate	0:6dee052a3fa4	433	s32_t *oid_ptr;
nandgate	0:6dee052a3fa4	434
nandgate	0:6dee052a3fa4	435	plen = 0;
nandgate	0:6dee052a3fa4	436	while (p != NULL)
nandgate	0:6dee052a3fa4	437	{
nandgate	0:6dee052a3fa4	438	base = plen;
nandgate	0:6dee052a3fa4	439	plen += p->len;
nandgate	0:6dee052a3fa4	440	if (ofs < plen)
nandgate	0:6dee052a3fa4	441	{
nandgate	0:6dee052a3fa4	442	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	443	msg_ptr += ofs - base;
nandgate	0:6dee052a3fa4	444
nandgate	0:6dee052a3fa4	445	oid->len = 0;
nandgate	0:6dee052a3fa4	446	oid_ptr = &oid->id[0];
nandgate	0:6dee052a3fa4	447	if (len > 0)
nandgate	0:6dee052a3fa4	448	{
nandgate	0:6dee052a3fa4	449	/* first compressed octet */
nandgate	0:6dee052a3fa4	450	if (*msg_ptr == 0x2B)
nandgate	0:6dee052a3fa4	451	{
nandgate	0:6dee052a3fa4	452	/* (most) common case 1.3 (iso.org) */
nandgate	0:6dee052a3fa4	453	*oid_ptr = 1;
nandgate	0:6dee052a3fa4	454	oid_ptr++;
nandgate	0:6dee052a3fa4	455	*oid_ptr = 3;
nandgate	0:6dee052a3fa4	456	oid_ptr++;
nandgate	0:6dee052a3fa4	457	}
nandgate	0:6dee052a3fa4	458	else if (*msg_ptr < 40)
nandgate	0:6dee052a3fa4	459	{
nandgate	0:6dee052a3fa4	460	*oid_ptr = 0;
nandgate	0:6dee052a3fa4	461	oid_ptr++;
nandgate	0:6dee052a3fa4	462	oid_ptr = msg_ptr;
nandgate	0:6dee052a3fa4	463	oid_ptr++;
nandgate	0:6dee052a3fa4	464	}
nandgate	0:6dee052a3fa4	465	else if (*msg_ptr < 80)
nandgate	0:6dee052a3fa4	466	{
nandgate	0:6dee052a3fa4	467	*oid_ptr = 1;
nandgate	0:6dee052a3fa4	468	oid_ptr++;
nandgate	0:6dee052a3fa4	469	oid_ptr = (msg_ptr) - 40;
nandgate	0:6dee052a3fa4	470	oid_ptr++;
nandgate	0:6dee052a3fa4	471	}
nandgate	0:6dee052a3fa4	472	else
nandgate	0:6dee052a3fa4	473	{
nandgate	0:6dee052a3fa4	474	*oid_ptr = 2;
nandgate	0:6dee052a3fa4	475	oid_ptr++;
nandgate	0:6dee052a3fa4	476	oid_ptr = (msg_ptr) - 80;
nandgate	0:6dee052a3fa4	477	oid_ptr++;
nandgate	0:6dee052a3fa4	478	}
nandgate	0:6dee052a3fa4	479	oid->len = 2;
nandgate	0:6dee052a3fa4	480	}
nandgate	0:6dee052a3fa4	481	else
nandgate	0:6dee052a3fa4	482	{
nandgate	0:6dee052a3fa4	483	/* accepting zero length identifiers e.g. for
nandgate	0:6dee052a3fa4	484	getnext operation. uncommon but valid */
nandgate	0:6dee052a3fa4	485	return ERR_OK;
nandgate	0:6dee052a3fa4	486	}
nandgate	0:6dee052a3fa4	487	len--;
nandgate	0:6dee052a3fa4	488	if (len > 0)
nandgate	0:6dee052a3fa4	489	{
nandgate	0:6dee052a3fa4	490	ofs += 1;
nandgate	0:6dee052a3fa4	491	if (ofs >= plen)
nandgate	0:6dee052a3fa4	492	{
nandgate	0:6dee052a3fa4	493	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	494	p = p->next;
nandgate	0:6dee052a3fa4	495	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	496	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	497	plen += p->len;
nandgate	0:6dee052a3fa4	498	}
nandgate	0:6dee052a3fa4	499	else
nandgate	0:6dee052a3fa4	500	{
nandgate	0:6dee052a3fa4	501	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	502	msg_ptr++;
nandgate	0:6dee052a3fa4	503	}
nandgate	0:6dee052a3fa4	504	}
nandgate	0:6dee052a3fa4	505	while ((len > 0) && (oid->len < LWIP_SNMP_OBJ_ID_LEN))
nandgate	0:6dee052a3fa4	506	{
nandgate	0:6dee052a3fa4	507	/* sub-identifier uses multiple octets */
nandgate	0:6dee052a3fa4	508	if (*msg_ptr & 0x80)
nandgate	0:6dee052a3fa4	509	{
nandgate	0:6dee052a3fa4	510	s32_t sub_id = 0;
nandgate	0:6dee052a3fa4	511
nandgate	0:6dee052a3fa4	512	while ((*msg_ptr & 0x80) && (len > 1))
nandgate	0:6dee052a3fa4	513	{
nandgate	0:6dee052a3fa4	514	len--;
nandgate	0:6dee052a3fa4	515	sub_id = (sub_id << 7) + (*msg_ptr & ~0x80);
nandgate	0:6dee052a3fa4	516	ofs += 1;
nandgate	0:6dee052a3fa4	517	if (ofs >= plen)
nandgate	0:6dee052a3fa4	518	{
nandgate	0:6dee052a3fa4	519	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	520	p = p->next;
nandgate	0:6dee052a3fa4	521	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	522	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	523	plen += p->len;
nandgate	0:6dee052a3fa4	524	}
nandgate	0:6dee052a3fa4	525	else
nandgate	0:6dee052a3fa4	526	{
nandgate	0:6dee052a3fa4	527	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	528	msg_ptr++;
nandgate	0:6dee052a3fa4	529	}
nandgate	0:6dee052a3fa4	530	}
nandgate	0:6dee052a3fa4	531	if (!(*msg_ptr & 0x80) && (len > 0))
nandgate	0:6dee052a3fa4	532	{
nandgate	0:6dee052a3fa4	533	/* last octet sub-identifier */
nandgate	0:6dee052a3fa4	534	len--;
nandgate	0:6dee052a3fa4	535	sub_id = (sub_id << 7) + *msg_ptr;
nandgate	0:6dee052a3fa4	536	*oid_ptr = sub_id;
nandgate	0:6dee052a3fa4	537	}
nandgate	0:6dee052a3fa4	538	}
nandgate	0:6dee052a3fa4	539	else
nandgate	0:6dee052a3fa4	540	{
nandgate	0:6dee052a3fa4	541	/* !(msg_ptr & 0x80) sub-identifier uses single octet /
nandgate	0:6dee052a3fa4	542	len--;
nandgate	0:6dee052a3fa4	543	oid_ptr = msg_ptr;
nandgate	0:6dee052a3fa4	544	}
nandgate	0:6dee052a3fa4	545	if (len > 0)
nandgate	0:6dee052a3fa4	546	{
nandgate	0:6dee052a3fa4	547	/* remaining oid bytes available ... */
nandgate	0:6dee052a3fa4	548	ofs += 1;
nandgate	0:6dee052a3fa4	549	if (ofs >= plen)
nandgate	0:6dee052a3fa4	550	{
nandgate	0:6dee052a3fa4	551	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	552	p = p->next;
nandgate	0:6dee052a3fa4	553	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	554	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	555	plen += p->len;
nandgate	0:6dee052a3fa4	556	}
nandgate	0:6dee052a3fa4	557	else
nandgate	0:6dee052a3fa4	558	{
nandgate	0:6dee052a3fa4	559	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	560	msg_ptr++;
nandgate	0:6dee052a3fa4	561	}
nandgate	0:6dee052a3fa4	562	}
nandgate	0:6dee052a3fa4	563	oid_ptr++;
nandgate	0:6dee052a3fa4	564	oid->len++;
nandgate	0:6dee052a3fa4	565	}
nandgate	0:6dee052a3fa4	566	if (len == 0)
nandgate	0:6dee052a3fa4	567	{
nandgate	0:6dee052a3fa4	568	/* len == 0, end of oid */
nandgate	0:6dee052a3fa4	569	return ERR_OK;
nandgate	0:6dee052a3fa4	570	}
nandgate	0:6dee052a3fa4	571	else
nandgate	0:6dee052a3fa4	572	{
nandgate	0:6dee052a3fa4	573	/* len > 0, oid->len == LWIP_SNMP_OBJ_ID_LEN or malformed encoding */
nandgate	0:6dee052a3fa4	574	return ERR_ARG;
nandgate	0:6dee052a3fa4	575	}
nandgate	0:6dee052a3fa4	576
nandgate	0:6dee052a3fa4	577	}
nandgate	0:6dee052a3fa4	578	p = p->next;
nandgate	0:6dee052a3fa4	579	}
nandgate	0:6dee052a3fa4	580	/* p == NULL, ofs >= plen */
nandgate	0:6dee052a3fa4	581	return ERR_ARG;
nandgate	0:6dee052a3fa4	582	}
nandgate	0:6dee052a3fa4	583
nandgate	0:6dee052a3fa4	584	/**
nandgate	0:6dee052a3fa4	585	* Decodes (copies) raw data (ip-addresses, octet strings, opaque encoding)
nandgate	0:6dee052a3fa4	586	* from incoming message into array.
nandgate	0:6dee052a3fa4	587	*
nandgate	0:6dee052a3fa4	588	* @param p points to a pbuf holding an ASN1 coded raw data
nandgate	0:6dee052a3fa4	589	* @param ofs points to the offset within the pbuf chain of the ASN1 coded raw data
nandgate	0:6dee052a3fa4	590	* @param len length of the coded raw data (zero is valid, e.g. empty string!)
nandgate	0:6dee052a3fa4	591	* @param raw_len length of the raw return value
nandgate	0:6dee052a3fa4	592	* @param raw return raw bytes
nandgate	0:6dee052a3fa4	593	* @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
nandgate	0:6dee052a3fa4	594	*/
nandgate	0:6dee052a3fa4	595	err_t
nandgate	0:6dee052a3fa4	596	snmp_asn1_dec_raw(struct pbuf p, u16_t ofs, u16_t len, u16_t raw_len, u8_t raw)
nandgate	0:6dee052a3fa4	597	{
nandgate	0:6dee052a3fa4	598	u16_t plen, base;
nandgate	0:6dee052a3fa4	599	u8_t *msg_ptr;
nandgate	0:6dee052a3fa4	600
nandgate	0:6dee052a3fa4	601	if (len > 0)
nandgate	0:6dee052a3fa4	602	{
nandgate	0:6dee052a3fa4	603	plen = 0;
nandgate	0:6dee052a3fa4	604	while (p != NULL)
nandgate	0:6dee052a3fa4	605	{
nandgate	0:6dee052a3fa4	606	base = plen;
nandgate	0:6dee052a3fa4	607	plen += p->len;
nandgate	0:6dee052a3fa4	608	if (ofs < plen)
nandgate	0:6dee052a3fa4	609	{
nandgate	0:6dee052a3fa4	610	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	611	msg_ptr += ofs - base;
nandgate	0:6dee052a3fa4	612	if (raw_len >= len)
nandgate	0:6dee052a3fa4	613	{
nandgate	0:6dee052a3fa4	614	while (len > 1)
nandgate	0:6dee052a3fa4	615	{
nandgate	0:6dee052a3fa4	616	/* copy len - 1 octets */
nandgate	0:6dee052a3fa4	617	len--;
nandgate	0:6dee052a3fa4	618	raw = msg_ptr;
nandgate	0:6dee052a3fa4	619	raw++;
nandgate	0:6dee052a3fa4	620	ofs += 1;
nandgate	0:6dee052a3fa4	621	if (ofs >= plen)
nandgate	0:6dee052a3fa4	622	{
nandgate	0:6dee052a3fa4	623	/* next octet in next pbuf */
nandgate	0:6dee052a3fa4	624	p = p->next;
nandgate	0:6dee052a3fa4	625	if (p == NULL) { return ERR_ARG; }
nandgate	0:6dee052a3fa4	626	msg_ptr = p->payload;
nandgate	0:6dee052a3fa4	627	plen += p->len;
nandgate	0:6dee052a3fa4	628	}
nandgate	0:6dee052a3fa4	629	else
nandgate	0:6dee052a3fa4	630	{
nandgate	0:6dee052a3fa4	631	/* next octet in same pbuf */
nandgate	0:6dee052a3fa4	632	msg_ptr++;
nandgate	0:6dee052a3fa4	633	}
nandgate	0:6dee052a3fa4	634	}
nandgate	0:6dee052a3fa4	635	/* copy last octet */
nandgate	0:6dee052a3fa4	636	raw = msg_ptr;
nandgate	0:6dee052a3fa4	637	return ERR_OK;
nandgate	0:6dee052a3fa4	638	}
nandgate	0:6dee052a3fa4	639	else
nandgate	0:6dee052a3fa4	640	{
nandgate	0:6dee052a3fa4	641	/* raw_len < len, not enough dst space */
nandgate	0:6dee052a3fa4	642	return ERR_ARG;
nandgate	0:6dee052a3fa4	643	}
nandgate	0:6dee052a3fa4	644	}
nandgate	0:6dee052a3fa4	645	p = p->next;
nandgate	0:6dee052a3fa4	646	}
nandgate	0:6dee052a3fa4	647	/* p == NULL, ofs >= plen */
nandgate	0:6dee052a3fa4	648	return ERR_ARG;
nandgate	0:6dee052a3fa4	649	}
nandgate	0:6dee052a3fa4	650	else
nandgate	0:6dee052a3fa4	651	{
nandgate	0:6dee052a3fa4	652	/* len == 0, empty string */
nandgate	0:6dee052a3fa4	653	return ERR_OK;
nandgate	0:6dee052a3fa4	654	}
nandgate	0:6dee052a3fa4	655	}
nandgate	0:6dee052a3fa4	656
nandgate	0:6dee052a3fa4	657	#endif /* LWIP_SNMP */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	26 Jul 2011
Imports:	159
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	2
Followers:	9

Core/lwIP/core/snmp/asn1_dec.c@0:6dee052a3fa4, 2011-07-26 (annotated)

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