mbed official / lwip

Official mbed lwIP library (version 1.4.0)

Dependents:   LwIPNetworking NetServicesMin EthernetInterface EthernetInterface_RSF ... more

Legacy Networking Libraries

This is an mbed 2 networking library. For mbed OS 5, lwip has been integrated with built-in networking interfaces. The networking libraries have been revised to better support additional network stacks and thread safety here.

This library is based on the code of lwIP v1.4.0

Copyright (c) 2001, 2002 Swedish Institute of Computer Science.
All rights reserved. 

Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission. 

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
OF SUCH DAMAGE.

core/snmp/asn1_dec.c@0:51ac1d130fd4, 2012-06-22 (annotated)

Committer:
mbed_official
Date:
Fri Jun 22 09:25:39 2012 +0000
Revision:
0:51ac1d130fd4
Initial import from lwip-1.4.0: http://download.savannah.gnu.org/releases/lwip/lwip-1.4.0.zip

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:51ac1d130fd4 1 /**
mbed_official 0:51ac1d130fd4 2 * @file
mbed_official 0:51ac1d130fd4 3 * Abstract Syntax Notation One (ISO 8824, 8825) decoding
mbed_official 0:51ac1d130fd4 4 *
mbed_official 0:51ac1d130fd4 5 * @todo not optimised (yet), favor correctness over speed, favor speed over size
mbed_official 0:51ac1d130fd4 6 */
mbed_official 0:51ac1d130fd4 7
mbed_official 0:51ac1d130fd4 8 /*
mbed_official 0:51ac1d130fd4 9 * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
mbed_official 0:51ac1d130fd4 10 * All rights reserved.
mbed_official 0:51ac1d130fd4 11 *
mbed_official 0:51ac1d130fd4 12 * Redistribution and use in source and binary forms, with or without modification,
mbed_official 0:51ac1d130fd4 13 * are permitted provided that the following conditions are met:
mbed_official 0:51ac1d130fd4 14 *
mbed_official 0:51ac1d130fd4 15 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 0:51ac1d130fd4 16 * this list of conditions and the following disclaimer.
mbed_official 0:51ac1d130fd4 17 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 0:51ac1d130fd4 18 * this list of conditions and the following disclaimer in the documentation
mbed_official 0:51ac1d130fd4 19 * and/or other materials provided with the distribution.
mbed_official 0:51ac1d130fd4 20 * 3. The name of the author may not be used to endorse or promote products
mbed_official 0:51ac1d130fd4 21 * derived from this software without specific prior written permission.
mbed_official 0:51ac1d130fd4 22 *
mbed_official 0:51ac1d130fd4 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
mbed_official 0:51ac1d130fd4 24 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
mbed_official 0:51ac1d130fd4 25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
mbed_official 0:51ac1d130fd4 26 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
mbed_official 0:51ac1d130fd4 27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
mbed_official 0:51ac1d130fd4 28 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
mbed_official 0:51ac1d130fd4 29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
mbed_official 0:51ac1d130fd4 30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
mbed_official 0:51ac1d130fd4 31 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
mbed_official 0:51ac1d130fd4 32 * OF SUCH DAMAGE.
mbed_official 0:51ac1d130fd4 33 *
mbed_official 0:51ac1d130fd4 34 * Author: Christiaan Simons <christiaan.simons@axon.tv>
mbed_official 0:51ac1d130fd4 35 */
mbed_official 0:51ac1d130fd4 36
mbed_official 0:51ac1d130fd4 37 #include "lwip/opt.h"
mbed_official 0:51ac1d130fd4 38
mbed_official 0:51ac1d130fd4 39 #if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
mbed_official 0:51ac1d130fd4 40
mbed_official 0:51ac1d130fd4 41 #include "lwip/snmp_asn1.h"
mbed_official 0:51ac1d130fd4 42
mbed_official 0:51ac1d130fd4 43 /**
mbed_official 0:51ac1d130fd4 44 * Retrieves type field from incoming pbuf chain.
mbed_official 0:51ac1d130fd4 45 *
mbed_official 0:51ac1d130fd4 46 * @param p points to a pbuf holding an ASN1 coded type field
mbed_official 0:51ac1d130fd4 47 * @param ofs points to the offset within the pbuf chain of the ASN1 coded type field
mbed_official 0:51ac1d130fd4 48 * @param type return ASN1 type
mbed_official 0:51ac1d130fd4 49 * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
mbed_official 0:51ac1d130fd4 50 */
mbed_official 0:51ac1d130fd4 51 err_t
mbed_official 0:51ac1d130fd4 52 snmp_asn1_dec_type(struct pbuf *p, u16_t ofs, u8_t *type)
mbed_official 0:51ac1d130fd4 53 {
mbed_official 0:51ac1d130fd4 54 u16_t plen, base;
mbed_official 0:51ac1d130fd4 55 u8_t *msg_ptr;
mbed_official 0:51ac1d130fd4 56
mbed_official 0:51ac1d130fd4 57 plen = 0;
mbed_official 0:51ac1d130fd4 58 while (p != NULL)
mbed_official 0:51ac1d130fd4 59 {
mbed_official 0:51ac1d130fd4 60 base = plen;
mbed_official 0:51ac1d130fd4 61 plen += p->len;
mbed_official 0:51ac1d130fd4 62 if (ofs < plen)
mbed_official 0:51ac1d130fd4 63 {
mbed_official 0:51ac1d130fd4 64 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 65 msg_ptr += ofs - base;
mbed_official 0:51ac1d130fd4 66 *type = *msg_ptr;
mbed_official 0:51ac1d130fd4 67 return ERR_OK;
mbed_official 0:51ac1d130fd4 68 }
mbed_official 0:51ac1d130fd4 69 p = p->next;
mbed_official 0:51ac1d130fd4 70 }
mbed_official 0:51ac1d130fd4 71 /* p == NULL, ofs >= plen */
mbed_official 0:51ac1d130fd4 72 return ERR_ARG;
mbed_official 0:51ac1d130fd4 73 }
mbed_official 0:51ac1d130fd4 74
mbed_official 0:51ac1d130fd4 75 /**
mbed_official 0:51ac1d130fd4 76 * Decodes length field from incoming pbuf chain into host length.
mbed_official 0:51ac1d130fd4 77 *
mbed_official 0:51ac1d130fd4 78 * @param p points to a pbuf holding an ASN1 coded length
mbed_official 0:51ac1d130fd4 79 * @param ofs points to the offset within the pbuf chain of the ASN1 coded length
mbed_official 0:51ac1d130fd4 80 * @param octets_used returns number of octets used by the length code
mbed_official 0:51ac1d130fd4 81 * @param length return host order length, upto 64k
mbed_official 0:51ac1d130fd4 82 * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
mbed_official 0:51ac1d130fd4 83 */
mbed_official 0:51ac1d130fd4 84 err_t
mbed_official 0:51ac1d130fd4 85 snmp_asn1_dec_length(struct pbuf *p, u16_t ofs, u8_t *octets_used, u16_t *length)
mbed_official 0:51ac1d130fd4 86 {
mbed_official 0:51ac1d130fd4 87 u16_t plen, base;
mbed_official 0:51ac1d130fd4 88 u8_t *msg_ptr;
mbed_official 0:51ac1d130fd4 89
mbed_official 0:51ac1d130fd4 90 plen = 0;
mbed_official 0:51ac1d130fd4 91 while (p != NULL)
mbed_official 0:51ac1d130fd4 92 {
mbed_official 0:51ac1d130fd4 93 base = plen;
mbed_official 0:51ac1d130fd4 94 plen += p->len;
mbed_official 0:51ac1d130fd4 95 if (ofs < plen)
mbed_official 0:51ac1d130fd4 96 {
mbed_official 0:51ac1d130fd4 97 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 98 msg_ptr += ofs - base;
mbed_official 0:51ac1d130fd4 99
mbed_official 0:51ac1d130fd4 100 if (*msg_ptr < 0x80)
mbed_official 0:51ac1d130fd4 101 {
mbed_official 0:51ac1d130fd4 102 /* primitive definite length format */
mbed_official 0:51ac1d130fd4 103 *octets_used = 1;
mbed_official 0:51ac1d130fd4 104 *length = *msg_ptr;
mbed_official 0:51ac1d130fd4 105 return ERR_OK;
mbed_official 0:51ac1d130fd4 106 }
mbed_official 0:51ac1d130fd4 107 else if (*msg_ptr == 0x80)
mbed_official 0:51ac1d130fd4 108 {
mbed_official 0:51ac1d130fd4 109 /* constructed indefinite length format, termination with two zero octets */
mbed_official 0:51ac1d130fd4 110 u8_t zeros;
mbed_official 0:51ac1d130fd4 111 u8_t i;
mbed_official 0:51ac1d130fd4 112
mbed_official 0:51ac1d130fd4 113 *length = 0;
mbed_official 0:51ac1d130fd4 114 zeros = 0;
mbed_official 0:51ac1d130fd4 115 while (zeros != 2)
mbed_official 0:51ac1d130fd4 116 {
mbed_official 0:51ac1d130fd4 117 i = 2;
mbed_official 0:51ac1d130fd4 118 while (i > 0)
mbed_official 0:51ac1d130fd4 119 {
mbed_official 0:51ac1d130fd4 120 i--;
mbed_official 0:51ac1d130fd4 121 (*length) += 1;
mbed_official 0:51ac1d130fd4 122 ofs += 1;
mbed_official 0:51ac1d130fd4 123 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 124 {
mbed_official 0:51ac1d130fd4 125 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 126 p = p->next;
mbed_official 0:51ac1d130fd4 127 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 128 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 129 plen += p->len;
mbed_official 0:51ac1d130fd4 130 }
mbed_official 0:51ac1d130fd4 131 else
mbed_official 0:51ac1d130fd4 132 {
mbed_official 0:51ac1d130fd4 133 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 134 msg_ptr++;
mbed_official 0:51ac1d130fd4 135 }
mbed_official 0:51ac1d130fd4 136 if (*msg_ptr == 0)
mbed_official 0:51ac1d130fd4 137 {
mbed_official 0:51ac1d130fd4 138 zeros++;
mbed_official 0:51ac1d130fd4 139 if (zeros == 2)
mbed_official 0:51ac1d130fd4 140 {
mbed_official 0:51ac1d130fd4 141 /* stop while (i > 0) */
mbed_official 0:51ac1d130fd4 142 i = 0;
mbed_official 0:51ac1d130fd4 143 }
mbed_official 0:51ac1d130fd4 144 }
mbed_official 0:51ac1d130fd4 145 else
mbed_official 0:51ac1d130fd4 146 {
mbed_official 0:51ac1d130fd4 147 zeros = 0;
mbed_official 0:51ac1d130fd4 148 }
mbed_official 0:51ac1d130fd4 149 }
mbed_official 0:51ac1d130fd4 150 }
mbed_official 0:51ac1d130fd4 151 *octets_used = 1;
mbed_official 0:51ac1d130fd4 152 return ERR_OK;
mbed_official 0:51ac1d130fd4 153 }
mbed_official 0:51ac1d130fd4 154 else if (*msg_ptr == 0x81)
mbed_official 0:51ac1d130fd4 155 {
mbed_official 0:51ac1d130fd4 156 /* constructed definite length format, one octet */
mbed_official 0:51ac1d130fd4 157 ofs += 1;
mbed_official 0:51ac1d130fd4 158 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 159 {
mbed_official 0:51ac1d130fd4 160 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 161 p = p->next;
mbed_official 0:51ac1d130fd4 162 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 163 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 164 }
mbed_official 0:51ac1d130fd4 165 else
mbed_official 0:51ac1d130fd4 166 {
mbed_official 0:51ac1d130fd4 167 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 168 msg_ptr++;
mbed_official 0:51ac1d130fd4 169 }
mbed_official 0:51ac1d130fd4 170 *length = *msg_ptr;
mbed_official 0:51ac1d130fd4 171 *octets_used = 2;
mbed_official 0:51ac1d130fd4 172 return ERR_OK;
mbed_official 0:51ac1d130fd4 173 }
mbed_official 0:51ac1d130fd4 174 else if (*msg_ptr == 0x82)
mbed_official 0:51ac1d130fd4 175 {
mbed_official 0:51ac1d130fd4 176 u8_t i;
mbed_official 0:51ac1d130fd4 177
mbed_official 0:51ac1d130fd4 178 /* constructed definite length format, two octets */
mbed_official 0:51ac1d130fd4 179 i = 2;
mbed_official 0:51ac1d130fd4 180 while (i > 0)
mbed_official 0:51ac1d130fd4 181 {
mbed_official 0:51ac1d130fd4 182 i--;
mbed_official 0:51ac1d130fd4 183 ofs += 1;
mbed_official 0:51ac1d130fd4 184 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 185 {
mbed_official 0:51ac1d130fd4 186 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 187 p = p->next;
mbed_official 0:51ac1d130fd4 188 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 189 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 190 plen += p->len;
mbed_official 0:51ac1d130fd4 191 }
mbed_official 0:51ac1d130fd4 192 else
mbed_official 0:51ac1d130fd4 193 {
mbed_official 0:51ac1d130fd4 194 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 195 msg_ptr++;
mbed_official 0:51ac1d130fd4 196 }
mbed_official 0:51ac1d130fd4 197 if (i == 0)
mbed_official 0:51ac1d130fd4 198 {
mbed_official 0:51ac1d130fd4 199 /* least significant length octet */
mbed_official 0:51ac1d130fd4 200 *length |= *msg_ptr;
mbed_official 0:51ac1d130fd4 201 }
mbed_official 0:51ac1d130fd4 202 else
mbed_official 0:51ac1d130fd4 203 {
mbed_official 0:51ac1d130fd4 204 /* most significant length octet */
mbed_official 0:51ac1d130fd4 205 *length = (*msg_ptr) << 8;
mbed_official 0:51ac1d130fd4 206 }
mbed_official 0:51ac1d130fd4 207 }
mbed_official 0:51ac1d130fd4 208 *octets_used = 3;
mbed_official 0:51ac1d130fd4 209 return ERR_OK;
mbed_official 0:51ac1d130fd4 210 }
mbed_official 0:51ac1d130fd4 211 else
mbed_official 0:51ac1d130fd4 212 {
mbed_official 0:51ac1d130fd4 213 /* constructed definite length format 3..127 octets, this is too big (>64k) */
mbed_official 0:51ac1d130fd4 214 /** @todo: do we need to accept inefficient codings with many leading zero's? */
mbed_official 0:51ac1d130fd4 215 *octets_used = 1 + ((*msg_ptr) & 0x7f);
mbed_official 0:51ac1d130fd4 216 return ERR_ARG;
mbed_official 0:51ac1d130fd4 217 }
mbed_official 0:51ac1d130fd4 218 }
mbed_official 0:51ac1d130fd4 219 p = p->next;
mbed_official 0:51ac1d130fd4 220 }
mbed_official 0:51ac1d130fd4 221
mbed_official 0:51ac1d130fd4 222 /* p == NULL, ofs >= plen */
mbed_official 0:51ac1d130fd4 223 return ERR_ARG;
mbed_official 0:51ac1d130fd4 224 }
mbed_official 0:51ac1d130fd4 225
mbed_official 0:51ac1d130fd4 226 /**
mbed_official 0:51ac1d130fd4 227 * Decodes positive integer (counter, gauge, timeticks) into u32_t.
mbed_official 0:51ac1d130fd4 228 *
mbed_official 0:51ac1d130fd4 229 * @param p points to a pbuf holding an ASN1 coded integer
mbed_official 0:51ac1d130fd4 230 * @param ofs points to the offset within the pbuf chain of the ASN1 coded integer
mbed_official 0:51ac1d130fd4 231 * @param len length of the coded integer field
mbed_official 0:51ac1d130fd4 232 * @param value return host order integer
mbed_official 0:51ac1d130fd4 233 * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
mbed_official 0:51ac1d130fd4 234 *
mbed_official 0:51ac1d130fd4 235 * @note ASN coded integers are _always_ signed. E.g. +0xFFFF is coded
mbed_official 0:51ac1d130fd4 236 * as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value
mbed_official 0:51ac1d130fd4 237 * of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!!
mbed_official 0:51ac1d130fd4 238 */
mbed_official 0:51ac1d130fd4 239 err_t
mbed_official 0:51ac1d130fd4 240 snmp_asn1_dec_u32t(struct pbuf *p, u16_t ofs, u16_t len, u32_t *value)
mbed_official 0:51ac1d130fd4 241 {
mbed_official 0:51ac1d130fd4 242 u16_t plen, base;
mbed_official 0:51ac1d130fd4 243 u8_t *msg_ptr;
mbed_official 0:51ac1d130fd4 244
mbed_official 0:51ac1d130fd4 245 plen = 0;
mbed_official 0:51ac1d130fd4 246 while (p != NULL)
mbed_official 0:51ac1d130fd4 247 {
mbed_official 0:51ac1d130fd4 248 base = plen;
mbed_official 0:51ac1d130fd4 249 plen += p->len;
mbed_official 0:51ac1d130fd4 250 if (ofs < plen)
mbed_official 0:51ac1d130fd4 251 {
mbed_official 0:51ac1d130fd4 252 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 253 msg_ptr += ofs - base;
mbed_official 0:51ac1d130fd4 254 if ((len > 0) && (len < 6))
mbed_official 0:51ac1d130fd4 255 {
mbed_official 0:51ac1d130fd4 256 /* start from zero */
mbed_official 0:51ac1d130fd4 257 *value = 0;
mbed_official 0:51ac1d130fd4 258 if (*msg_ptr & 0x80)
mbed_official 0:51ac1d130fd4 259 {
mbed_official 0:51ac1d130fd4 260 /* negative, expecting zero sign bit! */
mbed_official 0:51ac1d130fd4 261 return ERR_ARG;
mbed_official 0:51ac1d130fd4 262 }
mbed_official 0:51ac1d130fd4 263 else
mbed_official 0:51ac1d130fd4 264 {
mbed_official 0:51ac1d130fd4 265 /* positive */
mbed_official 0:51ac1d130fd4 266 if ((len > 1) && (*msg_ptr == 0))
mbed_official 0:51ac1d130fd4 267 {
mbed_official 0:51ac1d130fd4 268 /* skip leading "sign byte" octet 0x00 */
mbed_official 0:51ac1d130fd4 269 len--;
mbed_official 0:51ac1d130fd4 270 ofs += 1;
mbed_official 0:51ac1d130fd4 271 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 272 {
mbed_official 0:51ac1d130fd4 273 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 274 p = p->next;
mbed_official 0:51ac1d130fd4 275 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 276 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 277 plen += p->len;
mbed_official 0:51ac1d130fd4 278 }
mbed_official 0:51ac1d130fd4 279 else
mbed_official 0:51ac1d130fd4 280 {
mbed_official 0:51ac1d130fd4 281 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 282 msg_ptr++;
mbed_official 0:51ac1d130fd4 283 }
mbed_official 0:51ac1d130fd4 284 }
mbed_official 0:51ac1d130fd4 285 }
mbed_official 0:51ac1d130fd4 286 /* OR octets with value */
mbed_official 0:51ac1d130fd4 287 while (len > 1)
mbed_official 0:51ac1d130fd4 288 {
mbed_official 0:51ac1d130fd4 289 len--;
mbed_official 0:51ac1d130fd4 290 *value |= *msg_ptr;
mbed_official 0:51ac1d130fd4 291 *value <<= 8;
mbed_official 0:51ac1d130fd4 292 ofs += 1;
mbed_official 0:51ac1d130fd4 293 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 294 {
mbed_official 0:51ac1d130fd4 295 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 296 p = p->next;
mbed_official 0:51ac1d130fd4 297 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 298 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 299 plen += p->len;
mbed_official 0:51ac1d130fd4 300 }
mbed_official 0:51ac1d130fd4 301 else
mbed_official 0:51ac1d130fd4 302 {
mbed_official 0:51ac1d130fd4 303 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 304 msg_ptr++;
mbed_official 0:51ac1d130fd4 305 }
mbed_official 0:51ac1d130fd4 306 }
mbed_official 0:51ac1d130fd4 307 *value |= *msg_ptr;
mbed_official 0:51ac1d130fd4 308 return ERR_OK;
mbed_official 0:51ac1d130fd4 309 }
mbed_official 0:51ac1d130fd4 310 else
mbed_official 0:51ac1d130fd4 311 {
mbed_official 0:51ac1d130fd4 312 return ERR_ARG;
mbed_official 0:51ac1d130fd4 313 }
mbed_official 0:51ac1d130fd4 314 }
mbed_official 0:51ac1d130fd4 315 p = p->next;
mbed_official 0:51ac1d130fd4 316 }
mbed_official 0:51ac1d130fd4 317 /* p == NULL, ofs >= plen */
mbed_official 0:51ac1d130fd4 318 return ERR_ARG;
mbed_official 0:51ac1d130fd4 319 }
mbed_official 0:51ac1d130fd4 320
mbed_official 0:51ac1d130fd4 321 /**
mbed_official 0:51ac1d130fd4 322 * Decodes integer into s32_t.
mbed_official 0:51ac1d130fd4 323 *
mbed_official 0:51ac1d130fd4 324 * @param p points to a pbuf holding an ASN1 coded integer
mbed_official 0:51ac1d130fd4 325 * @param ofs points to the offset within the pbuf chain of the ASN1 coded integer
mbed_official 0:51ac1d130fd4 326 * @param len length of the coded integer field
mbed_official 0:51ac1d130fd4 327 * @param value return host order integer
mbed_official 0:51ac1d130fd4 328 * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
mbed_official 0:51ac1d130fd4 329 *
mbed_official 0:51ac1d130fd4 330 * @note ASN coded integers are _always_ signed!
mbed_official 0:51ac1d130fd4 331 */
mbed_official 0:51ac1d130fd4 332 err_t
mbed_official 0:51ac1d130fd4 333 snmp_asn1_dec_s32t(struct pbuf *p, u16_t ofs, u16_t len, s32_t *value)
mbed_official 0:51ac1d130fd4 334 {
mbed_official 0:51ac1d130fd4 335 u16_t plen, base;
mbed_official 0:51ac1d130fd4 336 u8_t *msg_ptr;
mbed_official 0:51ac1d130fd4 337 #if BYTE_ORDER == LITTLE_ENDIAN
mbed_official 0:51ac1d130fd4 338 u8_t *lsb_ptr = (u8_t*)value;
mbed_official 0:51ac1d130fd4 339 #endif
mbed_official 0:51ac1d130fd4 340 #if BYTE_ORDER == BIG_ENDIAN
mbed_official 0:51ac1d130fd4 341 u8_t *lsb_ptr = (u8_t*)value + sizeof(s32_t) - 1;
mbed_official 0:51ac1d130fd4 342 #endif
mbed_official 0:51ac1d130fd4 343 u8_t sign;
mbed_official 0:51ac1d130fd4 344
mbed_official 0:51ac1d130fd4 345 plen = 0;
mbed_official 0:51ac1d130fd4 346 while (p != NULL)
mbed_official 0:51ac1d130fd4 347 {
mbed_official 0:51ac1d130fd4 348 base = plen;
mbed_official 0:51ac1d130fd4 349 plen += p->len;
mbed_official 0:51ac1d130fd4 350 if (ofs < plen)
mbed_official 0:51ac1d130fd4 351 {
mbed_official 0:51ac1d130fd4 352 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 353 msg_ptr += ofs - base;
mbed_official 0:51ac1d130fd4 354 if ((len > 0) && (len < 5))
mbed_official 0:51ac1d130fd4 355 {
mbed_official 0:51ac1d130fd4 356 if (*msg_ptr & 0x80)
mbed_official 0:51ac1d130fd4 357 {
mbed_official 0:51ac1d130fd4 358 /* negative, start from -1 */
mbed_official 0:51ac1d130fd4 359 *value = -1;
mbed_official 0:51ac1d130fd4 360 sign = 1;
mbed_official 0:51ac1d130fd4 361 }
mbed_official 0:51ac1d130fd4 362 else
mbed_official 0:51ac1d130fd4 363 {
mbed_official 0:51ac1d130fd4 364 /* positive, start from 0 */
mbed_official 0:51ac1d130fd4 365 *value = 0;
mbed_official 0:51ac1d130fd4 366 sign = 0;
mbed_official 0:51ac1d130fd4 367 }
mbed_official 0:51ac1d130fd4 368 /* OR/AND octets with value */
mbed_official 0:51ac1d130fd4 369 while (len > 1)
mbed_official 0:51ac1d130fd4 370 {
mbed_official 0:51ac1d130fd4 371 len--;
mbed_official 0:51ac1d130fd4 372 if (sign)
mbed_official 0:51ac1d130fd4 373 {
mbed_official 0:51ac1d130fd4 374 *lsb_ptr &= *msg_ptr;
mbed_official 0:51ac1d130fd4 375 *value <<= 8;
mbed_official 0:51ac1d130fd4 376 *lsb_ptr |= 255;
mbed_official 0:51ac1d130fd4 377 }
mbed_official 0:51ac1d130fd4 378 else
mbed_official 0:51ac1d130fd4 379 {
mbed_official 0:51ac1d130fd4 380 *lsb_ptr |= *msg_ptr;
mbed_official 0:51ac1d130fd4 381 *value <<= 8;
mbed_official 0:51ac1d130fd4 382 }
mbed_official 0:51ac1d130fd4 383 ofs += 1;
mbed_official 0:51ac1d130fd4 384 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 385 {
mbed_official 0:51ac1d130fd4 386 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 387 p = p->next;
mbed_official 0:51ac1d130fd4 388 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 389 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 390 plen += p->len;
mbed_official 0:51ac1d130fd4 391 }
mbed_official 0:51ac1d130fd4 392 else
mbed_official 0:51ac1d130fd4 393 {
mbed_official 0:51ac1d130fd4 394 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 395 msg_ptr++;
mbed_official 0:51ac1d130fd4 396 }
mbed_official 0:51ac1d130fd4 397 }
mbed_official 0:51ac1d130fd4 398 if (sign)
mbed_official 0:51ac1d130fd4 399 {
mbed_official 0:51ac1d130fd4 400 *lsb_ptr &= *msg_ptr;
mbed_official 0:51ac1d130fd4 401 }
mbed_official 0:51ac1d130fd4 402 else
mbed_official 0:51ac1d130fd4 403 {
mbed_official 0:51ac1d130fd4 404 *lsb_ptr |= *msg_ptr;
mbed_official 0:51ac1d130fd4 405 }
mbed_official 0:51ac1d130fd4 406 return ERR_OK;
mbed_official 0:51ac1d130fd4 407 }
mbed_official 0:51ac1d130fd4 408 else
mbed_official 0:51ac1d130fd4 409 {
mbed_official 0:51ac1d130fd4 410 return ERR_ARG;
mbed_official 0:51ac1d130fd4 411 }
mbed_official 0:51ac1d130fd4 412 }
mbed_official 0:51ac1d130fd4 413 p = p->next;
mbed_official 0:51ac1d130fd4 414 }
mbed_official 0:51ac1d130fd4 415 /* p == NULL, ofs >= plen */
mbed_official 0:51ac1d130fd4 416 return ERR_ARG;
mbed_official 0:51ac1d130fd4 417 }
mbed_official 0:51ac1d130fd4 418
mbed_official 0:51ac1d130fd4 419 /**
mbed_official 0:51ac1d130fd4 420 * Decodes object identifier from incoming message into array of s32_t.
mbed_official 0:51ac1d130fd4 421 *
mbed_official 0:51ac1d130fd4 422 * @param p points to a pbuf holding an ASN1 coded object identifier
mbed_official 0:51ac1d130fd4 423 * @param ofs points to the offset within the pbuf chain of the ASN1 coded object identifier
mbed_official 0:51ac1d130fd4 424 * @param len length of the coded object identifier
mbed_official 0:51ac1d130fd4 425 * @param oid return object identifier struct
mbed_official 0:51ac1d130fd4 426 * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
mbed_official 0:51ac1d130fd4 427 */
mbed_official 0:51ac1d130fd4 428 err_t
mbed_official 0:51ac1d130fd4 429 snmp_asn1_dec_oid(struct pbuf *p, u16_t ofs, u16_t len, struct snmp_obj_id *oid)
mbed_official 0:51ac1d130fd4 430 {
mbed_official 0:51ac1d130fd4 431 u16_t plen, base;
mbed_official 0:51ac1d130fd4 432 u8_t *msg_ptr;
mbed_official 0:51ac1d130fd4 433 s32_t *oid_ptr;
mbed_official 0:51ac1d130fd4 434
mbed_official 0:51ac1d130fd4 435 plen = 0;
mbed_official 0:51ac1d130fd4 436 while (p != NULL)
mbed_official 0:51ac1d130fd4 437 {
mbed_official 0:51ac1d130fd4 438 base = plen;
mbed_official 0:51ac1d130fd4 439 plen += p->len;
mbed_official 0:51ac1d130fd4 440 if (ofs < plen)
mbed_official 0:51ac1d130fd4 441 {
mbed_official 0:51ac1d130fd4 442 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 443 msg_ptr += ofs - base;
mbed_official 0:51ac1d130fd4 444
mbed_official 0:51ac1d130fd4 445 oid->len = 0;
mbed_official 0:51ac1d130fd4 446 oid_ptr = &oid->id[0];
mbed_official 0:51ac1d130fd4 447 if (len > 0)
mbed_official 0:51ac1d130fd4 448 {
mbed_official 0:51ac1d130fd4 449 /* first compressed octet */
mbed_official 0:51ac1d130fd4 450 if (*msg_ptr == 0x2B)
mbed_official 0:51ac1d130fd4 451 {
mbed_official 0:51ac1d130fd4 452 /* (most) common case 1.3 (iso.org) */
mbed_official 0:51ac1d130fd4 453 *oid_ptr = 1;
mbed_official 0:51ac1d130fd4 454 oid_ptr++;
mbed_official 0:51ac1d130fd4 455 *oid_ptr = 3;
mbed_official 0:51ac1d130fd4 456 oid_ptr++;
mbed_official 0:51ac1d130fd4 457 }
mbed_official 0:51ac1d130fd4 458 else if (*msg_ptr < 40)
mbed_official 0:51ac1d130fd4 459 {
mbed_official 0:51ac1d130fd4 460 *oid_ptr = 0;
mbed_official 0:51ac1d130fd4 461 oid_ptr++;
mbed_official 0:51ac1d130fd4 462 *oid_ptr = *msg_ptr;
mbed_official 0:51ac1d130fd4 463 oid_ptr++;
mbed_official 0:51ac1d130fd4 464 }
mbed_official 0:51ac1d130fd4 465 else if (*msg_ptr < 80)
mbed_official 0:51ac1d130fd4 466 {
mbed_official 0:51ac1d130fd4 467 *oid_ptr = 1;
mbed_official 0:51ac1d130fd4 468 oid_ptr++;
mbed_official 0:51ac1d130fd4 469 *oid_ptr = (*msg_ptr) - 40;
mbed_official 0:51ac1d130fd4 470 oid_ptr++;
mbed_official 0:51ac1d130fd4 471 }
mbed_official 0:51ac1d130fd4 472 else
mbed_official 0:51ac1d130fd4 473 {
mbed_official 0:51ac1d130fd4 474 *oid_ptr = 2;
mbed_official 0:51ac1d130fd4 475 oid_ptr++;
mbed_official 0:51ac1d130fd4 476 *oid_ptr = (*msg_ptr) - 80;
mbed_official 0:51ac1d130fd4 477 oid_ptr++;
mbed_official 0:51ac1d130fd4 478 }
mbed_official 0:51ac1d130fd4 479 oid->len = 2;
mbed_official 0:51ac1d130fd4 480 }
mbed_official 0:51ac1d130fd4 481 else
mbed_official 0:51ac1d130fd4 482 {
mbed_official 0:51ac1d130fd4 483 /* accepting zero length identifiers e.g. for
mbed_official 0:51ac1d130fd4 484 getnext operation. uncommon but valid */
mbed_official 0:51ac1d130fd4 485 return ERR_OK;
mbed_official 0:51ac1d130fd4 486 }
mbed_official 0:51ac1d130fd4 487 len--;
mbed_official 0:51ac1d130fd4 488 if (len > 0)
mbed_official 0:51ac1d130fd4 489 {
mbed_official 0:51ac1d130fd4 490 ofs += 1;
mbed_official 0:51ac1d130fd4 491 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 492 {
mbed_official 0:51ac1d130fd4 493 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 494 p = p->next;
mbed_official 0:51ac1d130fd4 495 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 496 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 497 plen += p->len;
mbed_official 0:51ac1d130fd4 498 }
mbed_official 0:51ac1d130fd4 499 else
mbed_official 0:51ac1d130fd4 500 {
mbed_official 0:51ac1d130fd4 501 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 502 msg_ptr++;
mbed_official 0:51ac1d130fd4 503 }
mbed_official 0:51ac1d130fd4 504 }
mbed_official 0:51ac1d130fd4 505 while ((len > 0) && (oid->len < LWIP_SNMP_OBJ_ID_LEN))
mbed_official 0:51ac1d130fd4 506 {
mbed_official 0:51ac1d130fd4 507 /* sub-identifier uses multiple octets */
mbed_official 0:51ac1d130fd4 508 if (*msg_ptr & 0x80)
mbed_official 0:51ac1d130fd4 509 {
mbed_official 0:51ac1d130fd4 510 s32_t sub_id = 0;
mbed_official 0:51ac1d130fd4 511
mbed_official 0:51ac1d130fd4 512 while ((*msg_ptr & 0x80) && (len > 1))
mbed_official 0:51ac1d130fd4 513 {
mbed_official 0:51ac1d130fd4 514 len--;
mbed_official 0:51ac1d130fd4 515 sub_id = (sub_id << 7) + (*msg_ptr & ~0x80);
mbed_official 0:51ac1d130fd4 516 ofs += 1;
mbed_official 0:51ac1d130fd4 517 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 518 {
mbed_official 0:51ac1d130fd4 519 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 520 p = p->next;
mbed_official 0:51ac1d130fd4 521 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 522 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 523 plen += p->len;
mbed_official 0:51ac1d130fd4 524 }
mbed_official 0:51ac1d130fd4 525 else
mbed_official 0:51ac1d130fd4 526 {
mbed_official 0:51ac1d130fd4 527 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 528 msg_ptr++;
mbed_official 0:51ac1d130fd4 529 }
mbed_official 0:51ac1d130fd4 530 }
mbed_official 0:51ac1d130fd4 531 if (!(*msg_ptr & 0x80) && (len > 0))
mbed_official 0:51ac1d130fd4 532 {
mbed_official 0:51ac1d130fd4 533 /* last octet sub-identifier */
mbed_official 0:51ac1d130fd4 534 len--;
mbed_official 0:51ac1d130fd4 535 sub_id = (sub_id << 7) + *msg_ptr;
mbed_official 0:51ac1d130fd4 536 *oid_ptr = sub_id;
mbed_official 0:51ac1d130fd4 537 }
mbed_official 0:51ac1d130fd4 538 }
mbed_official 0:51ac1d130fd4 539 else
mbed_official 0:51ac1d130fd4 540 {
mbed_official 0:51ac1d130fd4 541 /* !(*msg_ptr & 0x80) sub-identifier uses single octet */
mbed_official 0:51ac1d130fd4 542 len--;
mbed_official 0:51ac1d130fd4 543 *oid_ptr = *msg_ptr;
mbed_official 0:51ac1d130fd4 544 }
mbed_official 0:51ac1d130fd4 545 if (len > 0)
mbed_official 0:51ac1d130fd4 546 {
mbed_official 0:51ac1d130fd4 547 /* remaining oid bytes available ... */
mbed_official 0:51ac1d130fd4 548 ofs += 1;
mbed_official 0:51ac1d130fd4 549 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 550 {
mbed_official 0:51ac1d130fd4 551 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 552 p = p->next;
mbed_official 0:51ac1d130fd4 553 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 554 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 555 plen += p->len;
mbed_official 0:51ac1d130fd4 556 }
mbed_official 0:51ac1d130fd4 557 else
mbed_official 0:51ac1d130fd4 558 {
mbed_official 0:51ac1d130fd4 559 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 560 msg_ptr++;
mbed_official 0:51ac1d130fd4 561 }
mbed_official 0:51ac1d130fd4 562 }
mbed_official 0:51ac1d130fd4 563 oid_ptr++;
mbed_official 0:51ac1d130fd4 564 oid->len++;
mbed_official 0:51ac1d130fd4 565 }
mbed_official 0:51ac1d130fd4 566 if (len == 0)
mbed_official 0:51ac1d130fd4 567 {
mbed_official 0:51ac1d130fd4 568 /* len == 0, end of oid */
mbed_official 0:51ac1d130fd4 569 return ERR_OK;
mbed_official 0:51ac1d130fd4 570 }
mbed_official 0:51ac1d130fd4 571 else
mbed_official 0:51ac1d130fd4 572 {
mbed_official 0:51ac1d130fd4 573 /* len > 0, oid->len == LWIP_SNMP_OBJ_ID_LEN or malformed encoding */
mbed_official 0:51ac1d130fd4 574 return ERR_ARG;
mbed_official 0:51ac1d130fd4 575 }
mbed_official 0:51ac1d130fd4 576
mbed_official 0:51ac1d130fd4 577 }
mbed_official 0:51ac1d130fd4 578 p = p->next;
mbed_official 0:51ac1d130fd4 579 }
mbed_official 0:51ac1d130fd4 580 /* p == NULL, ofs >= plen */
mbed_official 0:51ac1d130fd4 581 return ERR_ARG;
mbed_official 0:51ac1d130fd4 582 }
mbed_official 0:51ac1d130fd4 583
mbed_official 0:51ac1d130fd4 584 /**
mbed_official 0:51ac1d130fd4 585 * Decodes (copies) raw data (ip-addresses, octet strings, opaque encoding)
mbed_official 0:51ac1d130fd4 586 * from incoming message into array.
mbed_official 0:51ac1d130fd4 587 *
mbed_official 0:51ac1d130fd4 588 * @param p points to a pbuf holding an ASN1 coded raw data
mbed_official 0:51ac1d130fd4 589 * @param ofs points to the offset within the pbuf chain of the ASN1 coded raw data
mbed_official 0:51ac1d130fd4 590 * @param len length of the coded raw data (zero is valid, e.g. empty string!)
mbed_official 0:51ac1d130fd4 591 * @param raw_len length of the raw return value
mbed_official 0:51ac1d130fd4 592 * @param raw return raw bytes
mbed_official 0:51ac1d130fd4 593 * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
mbed_official 0:51ac1d130fd4 594 */
mbed_official 0:51ac1d130fd4 595 err_t
mbed_official 0:51ac1d130fd4 596 snmp_asn1_dec_raw(struct pbuf *p, u16_t ofs, u16_t len, u16_t raw_len, u8_t *raw)
mbed_official 0:51ac1d130fd4 597 {
mbed_official 0:51ac1d130fd4 598 u16_t plen, base;
mbed_official 0:51ac1d130fd4 599 u8_t *msg_ptr;
mbed_official 0:51ac1d130fd4 600
mbed_official 0:51ac1d130fd4 601 if (len > 0)
mbed_official 0:51ac1d130fd4 602 {
mbed_official 0:51ac1d130fd4 603 plen = 0;
mbed_official 0:51ac1d130fd4 604 while (p != NULL)
mbed_official 0:51ac1d130fd4 605 {
mbed_official 0:51ac1d130fd4 606 base = plen;
mbed_official 0:51ac1d130fd4 607 plen += p->len;
mbed_official 0:51ac1d130fd4 608 if (ofs < plen)
mbed_official 0:51ac1d130fd4 609 {
mbed_official 0:51ac1d130fd4 610 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 611 msg_ptr += ofs - base;
mbed_official 0:51ac1d130fd4 612 if (raw_len >= len)
mbed_official 0:51ac1d130fd4 613 {
mbed_official 0:51ac1d130fd4 614 while (len > 1)
mbed_official 0:51ac1d130fd4 615 {
mbed_official 0:51ac1d130fd4 616 /* copy len - 1 octets */
mbed_official 0:51ac1d130fd4 617 len--;
mbed_official 0:51ac1d130fd4 618 *raw = *msg_ptr;
mbed_official 0:51ac1d130fd4 619 raw++;
mbed_official 0:51ac1d130fd4 620 ofs += 1;
mbed_official 0:51ac1d130fd4 621 if (ofs >= plen)
mbed_official 0:51ac1d130fd4 622 {
mbed_official 0:51ac1d130fd4 623 /* next octet in next pbuf */
mbed_official 0:51ac1d130fd4 624 p = p->next;
mbed_official 0:51ac1d130fd4 625 if (p == NULL) { return ERR_ARG; }
mbed_official 0:51ac1d130fd4 626 msg_ptr = (u8_t*)p->payload;
mbed_official 0:51ac1d130fd4 627 plen += p->len;
mbed_official 0:51ac1d130fd4 628 }
mbed_official 0:51ac1d130fd4 629 else
mbed_official 0:51ac1d130fd4 630 {
mbed_official 0:51ac1d130fd4 631 /* next octet in same pbuf */
mbed_official 0:51ac1d130fd4 632 msg_ptr++;
mbed_official 0:51ac1d130fd4 633 }
mbed_official 0:51ac1d130fd4 634 }
mbed_official 0:51ac1d130fd4 635 /* copy last octet */
mbed_official 0:51ac1d130fd4 636 *raw = *msg_ptr;
mbed_official 0:51ac1d130fd4 637 return ERR_OK;
mbed_official 0:51ac1d130fd4 638 }
mbed_official 0:51ac1d130fd4 639 else
mbed_official 0:51ac1d130fd4 640 {
mbed_official 0:51ac1d130fd4 641 /* raw_len < len, not enough dst space */
mbed_official 0:51ac1d130fd4 642 return ERR_ARG;
mbed_official 0:51ac1d130fd4 643 }
mbed_official 0:51ac1d130fd4 644 }
mbed_official 0:51ac1d130fd4 645 p = p->next;
mbed_official 0:51ac1d130fd4 646 }
mbed_official 0:51ac1d130fd4 647 /* p == NULL, ofs >= plen */
mbed_official 0:51ac1d130fd4 648 return ERR_ARG;
mbed_official 0:51ac1d130fd4 649 }
mbed_official 0:51ac1d130fd4 650 else
mbed_official 0:51ac1d130fd4 651 {
mbed_official 0:51ac1d130fd4 652 /* len == 0, empty string */
mbed_official 0:51ac1d130fd4 653 return ERR_OK;
mbed_official 0:51ac1d130fd4 654 }
mbed_official 0:51ac1d130fd4 655 }
mbed_official 0:51ac1d130fd4 656
mbed_official 0:51ac1d130fd4 657 #endif /* LWIP_SNMP */