Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 1 | /*- |
| 2 | * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| 3 | * Redistribution and modifications are permitted subject to BSD license. |
| 4 | */ |
| 5 | #include <constr_TYPE.h> |
| 6 | #include <ber_tlv_tag.h> |
| 7 | #include <errno.h> |
| 8 | |
| 9 | ssize_t |
| 10 | ber_fetch_tag(void *ptr, size_t size, ber_tlv_tag_t *tag_r) { |
| 11 | ber_tlv_tag_t val; |
| 12 | ber_tlv_tag_t tclass; |
Lev Walkin | d9bd775 | 2004-06-05 08:17:50 +0000 | [diff] [blame] | 13 | size_t skipped; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 14 | |
| 15 | if(size == 0) |
| 16 | return 0; |
| 17 | |
| 18 | val = *(uint8_t *)ptr; |
| 19 | tclass = (val >> 6); |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 20 | if((val &= 0x1F) != 0x1F) { |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 21 | /* |
| 22 | * Simple form: everything encoded in a single octet. |
| 23 | * Tag Class is encoded using two least significant bits. |
| 24 | */ |
| 25 | *tag_r = (val << 2) | tclass; |
| 26 | return 1; |
| 27 | } |
| 28 | |
| 29 | /* |
| 30 | * Each octet contains 7 bits of useful information. |
| 31 | * The MSB is 0 if it is the last octet of the tag. |
| 32 | */ |
Lev Walkin | 4ce78ca | 2004-08-25 01:34:11 +0000 | [diff] [blame] | 33 | for(val = 0, ptr = ((char *)ptr) + 1, skipped = 2; |
| 34 | skipped <= size; ptr = ((char *)ptr) + 1, skipped++) { |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 35 | unsigned int oct = *(uint8_t *)ptr; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 36 | if(oct & 0x80) { |
| 37 | val = (val << 7) | (oct & 0x7F); |
| 38 | /* |
| 39 | * Make sure there are at least 9 bits spare |
| 40 | * at the MS side of a value. |
| 41 | */ |
| 42 | if(val >> ((8 * sizeof(val)) - 9)) { |
| 43 | /* |
| 44 | * We would not be able to accomodate |
| 45 | * any more tag bits. |
| 46 | */ |
| 47 | return -1; |
| 48 | } |
| 49 | } else { |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 50 | val = (val << 7) | oct; |
| 51 | *tag_r = (val << 2) | tclass; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 52 | return skipped; |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | return 0; /* Want more */ |
| 57 | } |
| 58 | |
| 59 | |
| 60 | ssize_t |
| 61 | ber_tlv_tag_fwrite(ber_tlv_tag_t tag, FILE *f) { |
| 62 | char buf[sizeof("[APPLICATION ]") + 32]; |
| 63 | ssize_t ret; |
| 64 | |
| 65 | ret = ber_tlv_tag_snprint(tag, buf, sizeof(buf)); |
Lev Walkin | d9bd775 | 2004-06-05 08:17:50 +0000 | [diff] [blame] | 66 | if(ret >= (ssize_t)sizeof(buf) || ret < 2) { |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 67 | errno = EPERM; |
| 68 | return -1; |
| 69 | } |
| 70 | |
| 71 | return fwrite(buf, 1, ret, f); |
| 72 | } |
| 73 | |
| 74 | ssize_t |
| 75 | ber_tlv_tag_snprint(ber_tlv_tag_t tag, char *buf, size_t size) { |
| 76 | char *type = 0; |
| 77 | int ret; |
| 78 | |
| 79 | switch(tag & 0x3) { |
| 80 | case ASN_TAG_CLASS_UNIVERSAL: type = "UNIVERSAL "; break; |
| 81 | case ASN_TAG_CLASS_APPLICATION: type = "APPLICATION "; break; |
| 82 | case ASN_TAG_CLASS_CONTEXT: type = ""; break; |
| 83 | case ASN_TAG_CLASS_PRIVATE: type = "PRIVATE "; break; |
| 84 | } |
| 85 | |
| 86 | ret = snprintf(buf, size, "[%s%u]", type, ((unsigned)tag) >> 2); |
| 87 | if(ret <= 0 && size) buf[0] = '\0'; /* against broken libc's */ |
| 88 | |
| 89 | return ret; |
| 90 | } |
| 91 | |
| 92 | char * |
| 93 | ber_tlv_tag_string(ber_tlv_tag_t tag) { |
| 94 | static char buf[sizeof("[APPLICATION ]") + 32]; |
| 95 | |
| 96 | (void)ber_tlv_tag_snprint(tag, buf, sizeof(buf)); |
| 97 | |
| 98 | return buf; |
| 99 | } |
| 100 | |
| 101 | |
| 102 | ssize_t |
Lev Walkin | 2ca9543 | 2004-08-19 13:27:34 +0000 | [diff] [blame] | 103 | ber_tlv_tag_serialize(ber_tlv_tag_t tag, void *bufp, size_t size) { |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 104 | int tclass = BER_TAG_CLASS(tag); |
| 105 | ber_tlv_tag_t tval = BER_TAG_VALUE(tag); |
Lev Walkin | c234657 | 2004-08-11 09:07:36 +0000 | [diff] [blame] | 106 | uint8_t *buf = (uint8_t *)bufp; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 107 | uint8_t *end; |
Lev Walkin | b2ce577 | 2004-08-18 08:23:43 +0000 | [diff] [blame] | 108 | size_t required_size; |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 109 | size_t i; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 110 | |
| 111 | if(tval <= 30) { |
| 112 | /* Encoded in 1 octet */ |
| 113 | if(size) buf[0] = (tclass << 6) | tval; |
| 114 | return 1; |
| 115 | } else if(size) { |
| 116 | *buf++ = (tclass << 6) | 0x1F; |
| 117 | size--; |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * Compute the size of the subsequent bytes. |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 122 | */ |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 123 | for(required_size = 1, i = 7; i < 8 * sizeof(tval); i += 7) { |
| 124 | if(tval >> i) |
Lev Walkin | b2ce577 | 2004-08-18 08:23:43 +0000 | [diff] [blame] | 125 | required_size++; |
| 126 | else |
| 127 | break; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 128 | } |
| 129 | |
Lev Walkin | b2ce577 | 2004-08-18 08:23:43 +0000 | [diff] [blame] | 130 | if(size < required_size) |
| 131 | return required_size + 1; |
| 132 | |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 133 | /* |
| 134 | * Fill in the buffer, space permitting. |
| 135 | */ |
Lev Walkin | b2ce577 | 2004-08-18 08:23:43 +0000 | [diff] [blame] | 136 | end = buf + required_size - 1; |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 137 | for(i -= 7; buf < end; i -= 7, buf++) |
Lev Walkin | b2ce577 | 2004-08-18 08:23:43 +0000 | [diff] [blame] | 138 | *buf = 0x80 | ((tval >> i) & 0x7F); |
Lev Walkin | 8f3b506 | 2004-08-18 09:01:45 +0000 | [diff] [blame] | 139 | *buf = (tval & 0x7F); /* Last octet without high bit */ |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 140 | |
Lev Walkin | b2ce577 | 2004-08-18 08:23:43 +0000 | [diff] [blame] | 141 | return required_size + 1; |
Lev Walkin | f15320b | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 142 | } |
| 143 | |