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