diff options
Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/net/lwip/lwip/core/snmp/asn1_dec.c')
| -rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/net/lwip/lwip/core/snmp/asn1_dec.c | 657 |
1 files changed, 657 insertions, 0 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/net/lwip/lwip/core/snmp/asn1_dec.c b/tmk_core/tool/mbed/mbed-sdk/libraries/net/lwip/lwip/core/snmp/asn1_dec.c new file mode 100644 index 0000000000..1d5658207a --- /dev/null +++ b/tmk_core/tool/mbed/mbed-sdk/libraries/net/lwip/lwip/core/snmp/asn1_dec.c @@ -0,0 +1,657 @@ +/** + * @file + * Abstract Syntax Notation One (ISO 8824, 8825) decoding + * + * @todo not optimised (yet), favor correctness over speed, favor speed over size + */ + +/* + * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands. + * 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. + * + * Author: Christiaan Simons <christiaan.simons@axon.tv> + */ + +#include "lwip/opt.h" + +#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */ + +#include "lwip/snmp_asn1.h" + +/** + * Retrieves type field from incoming pbuf chain. + * + * @param p points to a pbuf holding an ASN1 coded type field + * @param ofs points to the offset within the pbuf chain of the ASN1 coded type field + * @param type return ASN1 type + * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode + */ +err_t +snmp_asn1_dec_type(struct pbuf *p, u16_t ofs, u8_t *type) +{ + u16_t plen, base; + u8_t *msg_ptr; + + plen = 0; + while (p != NULL) + { + base = plen; + plen += p->len; + if (ofs < plen) + { + msg_ptr = (u8_t*)p->payload; + msg_ptr += ofs - base; + *type = *msg_ptr; + return ERR_OK; + } + p = p->next; + } + /* p == NULL, ofs >= plen */ + return ERR_ARG; +} + +/** + * Decodes length field from incoming pbuf chain into host length. + * + * @param p points to a pbuf holding an ASN1 coded length + * @param ofs points to the offset within the pbuf chain of the ASN1 coded length + * @param octets_used returns number of octets used by the length code + * @param length return host order length, upto 64k + * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode + */ +err_t +snmp_asn1_dec_length(struct pbuf *p, u16_t ofs, u8_t *octets_used, u16_t *length) +{ + u16_t plen, base; + u8_t *msg_ptr; + + plen = 0; + while (p != NULL) + { + base = plen; + plen += p->len; + if (ofs < plen) + { + msg_ptr = (u8_t*)p->payload; + msg_ptr += ofs - base; + + if (*msg_ptr < 0x80) + { + /* primitive definite length format */ + *octets_used = 1; + *length = *msg_ptr; + return ERR_OK; + } + else if (*msg_ptr == 0x80) + { + /* constructed indefinite length format, termination with two zero octets */ + u8_t zeros; + u8_t i; + + *length = 0; + zeros = 0; + while (zeros != 2) + { + i = 2; + while (i > 0) + { + i--; + (*length) += 1; + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + if (*msg_ptr == 0) + { + zeros++; + if (zeros == 2) + { + /* stop while (i > 0) */ + i = 0; + } + } + else + { + zeros = 0; + } + } + } + *octets_used = 1; + return ERR_OK; + } + else if (*msg_ptr == 0x81) + { + /* constructed definite length format, one octet */ + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + *length = *msg_ptr; + *octets_used = 2; + return ERR_OK; + } + else if (*msg_ptr == 0x82) + { + u8_t i; + + /* constructed definite length format, two octets */ + i = 2; + while (i > 0) + { + i--; + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + if (i == 0) + { + /* least significant length octet */ + *length |= *msg_ptr; + } + else + { + /* most significant length octet */ + *length = (*msg_ptr) << 8; + } + } + *octets_used = 3; + return ERR_OK; + } + else + { + /* constructed definite length format 3..127 octets, this is too big (>64k) */ + /** @todo: do we need to accept inefficient codings with many leading zero's? */ + *octets_used = 1 + ((*msg_ptr) & 0x7f); + return ERR_ARG; + } + } + p = p->next; + } + + /* p == NULL, ofs >= plen */ + return ERR_ARG; +} + +/** + * Decodes positive integer (counter, gauge, timeticks) into u32_t. + * + * @param p points to a pbuf holding an ASN1 coded integer + * @param ofs points to the offset within the pbuf chain of the ASN1 coded integer + * @param len length of the coded integer field + * @param value return host order integer + * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode + * + * @note ASN coded integers are _always_ signed. E.g. +0xFFFF is coded + * as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value + * of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!! + */ +err_t +snmp_asn1_dec_u32t(struct pbuf *p, u16_t ofs, u16_t len, u32_t *value) +{ + u16_t plen, base; + u8_t *msg_ptr; + + plen = 0; + while (p != NULL) + { + base = plen; + plen += p->len; + if (ofs < plen) + { + msg_ptr = (u8_t*)p->payload; + msg_ptr += ofs - base; + if ((len > 0) && (len < 6)) + { + /* start from zero */ + *value = 0; + if (*msg_ptr & 0x80) + { + /* negative, expecting zero sign bit! */ + return ERR_ARG; + } + else + { + /* positive */ + if ((len > 1) && (*msg_ptr == 0)) + { + /* skip leading "sign byte" octet 0x00 */ + len--; + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + } + /* OR octets with value */ + while (len > 1) + { + len--; + *value |= *msg_ptr; + *value <<= 8; + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + *value |= *msg_ptr; + return ERR_OK; + } + else + { + return ERR_ARG; + } + } + p = p->next; + } + /* p == NULL, ofs >= plen */ + return ERR_ARG; +} + +/** + * Decodes integer into s32_t. + * + * @param p points to a pbuf holding an ASN1 coded integer + * @param ofs points to the offset within the pbuf chain of the ASN1 coded integer + * @param len length of the coded integer field + * @param value return host order integer + * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode + * + * @note ASN coded integers are _always_ signed! + */ +err_t +snmp_asn1_dec_s32t(struct pbuf *p, u16_t ofs, u16_t len, s32_t *value) +{ + u16_t plen, base; + u8_t *msg_ptr; +#if BYTE_ORDER == LITTLE_ENDIAN + u8_t *lsb_ptr = (u8_t*)value; +#endif +#if BYTE_ORDER == BIG_ENDIAN + u8_t *lsb_ptr = (u8_t*)value + sizeof(s32_t) - 1; +#endif + u8_t sign; + + plen = 0; + while (p != NULL) + { + base = plen; + plen += p->len; + if (ofs < plen) + { + msg_ptr = (u8_t*)p->payload; + msg_ptr += ofs - base; + if ((len > 0) && (len < 5)) + { + if (*msg_ptr & 0x80) + { + /* negative, start from -1 */ + *value = -1; + sign = 1; + } + else + { + /* positive, start from 0 */ + *value = 0; + sign = 0; + } + /* OR/AND octets with value */ + while (len > 1) + { + len--; + if (sign) + { + *lsb_ptr &= *msg_ptr; + *value <<= 8; + *lsb_ptr |= 255; + } + else + { + *lsb_ptr |= *msg_ptr; + *value <<= 8; + } + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + if (sign) + { + *lsb_ptr &= *msg_ptr; + } + else + { + *lsb_ptr |= *msg_ptr; + } + return ERR_OK; + } + else + { + return ERR_ARG; + } + } + p = p->next; + } + /* p == NULL, ofs >= plen */ + return ERR_ARG; +} + +/** + * Decodes object identifier from incoming message into array of s32_t. + * + * @param p points to a pbuf holding an ASN1 coded object identifier + * @param ofs points to the offset within the pbuf chain of the ASN1 coded object identifier + * @param len length of the coded object identifier + * @param oid return object identifier struct + * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode + */ +err_t +snmp_asn1_dec_oid(struct pbuf *p, u16_t ofs, u16_t len, struct snmp_obj_id *oid) +{ + u16_t plen, base; + u8_t *msg_ptr; + s32_t *oid_ptr; + + plen = 0; + while (p != NULL) + { + base = plen; + plen += p->len; + if (ofs < plen) + { + msg_ptr = (u8_t*)p->payload; + msg_ptr += ofs - base; + + oid->len = 0; + oid_ptr = &oid->id[0]; + if (len > 0) + { + /* first compressed octet */ + if (*msg_ptr == 0x2B) + { + /* (most) common case 1.3 (iso.org) */ + *oid_ptr = 1; + oid_ptr++; + *oid_ptr = 3; + oid_ptr++; + } + else if (*msg_ptr < 40) + { + *oid_ptr = 0; + oid_ptr++; + *oid_ptr = *msg_ptr; + oid_ptr++; + } + else if (*msg_ptr < 80) + { + *oid_ptr = 1; + oid_ptr++; + *oid_ptr = (*msg_ptr) - 40; + oid_ptr++; + } + else + { + *oid_ptr = 2; + oid_ptr++; + *oid_ptr = (*msg_ptr) - 80; + oid_ptr++; + } + oid->len = 2; + } + else + { + /* accepting zero length identifiers e.g. for + getnext operation. uncommon but valid */ + return ERR_OK; + } + len--; + if (len > 0) + { + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + while ((len > 0) && (oid->len < LWIP_SNMP_OBJ_ID_LEN)) + { + /* sub-identifier uses multiple octets */ + if (*msg_ptr & 0x80) + { + s32_t sub_id = 0; + + while ((*msg_ptr & 0x80) && (len > 1)) + { + len--; + sub_id = (sub_id << 7) + (*msg_ptr & ~0x80); + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + if (!(*msg_ptr & 0x80) && (len > 0)) + { + /* last octet sub-identifier */ + len--; + sub_id = (sub_id << 7) + *msg_ptr; + *oid_ptr = sub_id; + } + } + else + { + /* !(*msg_ptr & 0x80) sub-identifier uses single octet */ + len--; + *oid_ptr = *msg_ptr; + } + if (len > 0) + { + /* remaining oid bytes available ... */ + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + oid_ptr++; + oid->len++; + } + if (len == 0) + { + /* len == 0, end of oid */ + return ERR_OK; + } + else + { + /* len > 0, oid->len == LWIP_SNMP_OBJ_ID_LEN or malformed encoding */ + return ERR_ARG; + } + + } + p = p->next; + } + /* p == NULL, ofs >= plen */ + return ERR_ARG; +} + +/** + * Decodes (copies) raw data (ip-addresses, octet strings, opaque encoding) + * from incoming message into array. + * + * @param p points to a pbuf holding an ASN1 coded raw data + * @param ofs points to the offset within the pbuf chain of the ASN1 coded raw data + * @param len length of the coded raw data (zero is valid, e.g. empty string!) + * @param raw_len length of the raw return value + * @param raw return raw bytes + * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode + */ +err_t +snmp_asn1_dec_raw(struct pbuf *p, u16_t ofs, u16_t len, u16_t raw_len, u8_t *raw) +{ + u16_t plen, base; + u8_t *msg_ptr; + + if (len > 0) + { + plen = 0; + while (p != NULL) + { + base = plen; + plen += p->len; + if (ofs < plen) + { + msg_ptr = (u8_t*)p->payload; + msg_ptr += ofs - base; + if (raw_len >= len) + { + while (len > 1) + { + /* copy len - 1 octets */ + len--; + *raw = *msg_ptr; + raw++; + ofs += 1; + if (ofs >= plen) + { + /* next octet in next pbuf */ + p = p->next; + if (p == NULL) { return ERR_ARG; } + msg_ptr = (u8_t*)p->payload; + plen += p->len; + } + else + { + /* next octet in same pbuf */ + msg_ptr++; + } + } + /* copy last octet */ + *raw = *msg_ptr; + return ERR_OK; + } + else + { + /* raw_len < len, not enough dst space */ + return ERR_ARG; + } + } + p = p->next; + } + /* p == NULL, ofs >= plen */ + return ERR_ARG; + } + else + { + /* len == 0, empty string */ + return ERR_OK; + } +} + +#endif /* LWIP_SNMP */ |