5 Author: Pekka Riikonen <priikone@silcnet.org>
7 Copyright (C) 2003 - 2008 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; version 2 of the License.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
20 /****h* silcasn1/BER Interface
24 * The Basic Encoding Rules (BER) is the data encoding format for the
25 * ASN.1. This interface provides routines for encoding and decoding
26 * arbitraty BER data blocks. Naturally, this interface can be used
27 * to encode and decode DER blocks as well. These routines does not
28 * allocate any memory and have been optimized for general ASN.1 usage.
30 * References: ITU-T X.690
31 * http://www.itu.int/ITU-T/studygroups/com17/languages/X690_0702.pdf
38 /****d* silcasn1/SilcBerClass
42 * typedef enum { ... } SilcBerClass;
46 * Defines the BER classes.
51 SILC_BER_CLASS_UNIVERSAL = 0x00, /* Universal */
52 SILC_BER_CLASS_APPLICATION = 0x01, /* Application */
53 SILC_BER_CLASS_CONTEXT = 0x02, /* Context-specific */
54 SILC_BER_CLASS_PRIVATE = 0x03, /* Private */
58 /****d* silcasn1/SilcBerEncoding
62 * typedef enum { ... } SilcBerEncoding;
66 * Defines the BER encoding type.
71 SILC_BER_ENC_PRIMITIVE = 0x00,
72 SILC_BER_ENC_CONSTRUCTED = 0x01,
76 /****f* silcasn1/silc_ber_encode
81 * silc_ber_encode(SilcBuffer ber, SilcBerClass ber_class,
82 * SilcBerEncoding encoding, SilcUInt32 tag,
83 * const unsigned char *data, SilcUInt32 data_len,
84 * SilcBool indefinite);
88 * Encodes a BER data block into the `ber', which must already have
89 * sufficient space allocated. Caller can use silc_ber_encoded_len
90 * function to determine how much to allocate space before calling this
91 * function. If the `indefinite' is TRUE then the BER block will not
92 * include the length of the data in the BER block.
95 SilcBool silc_ber_encode(SilcBuffer ber, SilcBerClass ber_class,
96 SilcBerEncoding encoding, SilcUInt32 tag,
97 const unsigned char *data, SilcUInt32 data_len,
100 /****f* silcasn1/silc_ber_decode
105 * silc_ber_decode(SilcBuffer ber, SilcBerClass *ber_class,
106 * SilcBerEncoding *encoding, SilcUInt32 *tag,
107 * const unsigned char **data, SilcUInt32 *data_len,
108 * SilcBool *indefinite, SilcUInt32 *identifier_len);
112 * Decodesa a BER data from the buffer `ber'. Returns the class,
113 * encoding and the tag number for the BER data into `ber_class',
114 * `encoding' and `tag'. A pointer to the start of the data area is
115 * returned into `data'. If the length of the data is available from
116 * the BER data the length is returned into `data_len'. If the
117 * `indefinite' is TRUE then the length found in `data_len' was found
118 * by finding end-of-contents octets from the BER data. The
119 * `identifier_len' is the length of the BER header, and the length
120 * of the entire BER object is `identifier_len' + `data_len'.
123 SilcBool silc_ber_decode(SilcBuffer ber, SilcBerClass *ber_class,
124 SilcBerEncoding *encoding, SilcUInt32 *tag,
125 const unsigned char **data, SilcUInt32 *data_len,
126 SilcBool *indefinite, SilcUInt32 *identifier_len);
128 /****f* silcasn1/silc_ber_encoded_len
132 * SilcUInt32 silc_ber_encoded_len(SilcUInt32 tag, SilcUInt32 data_len,
133 * SilcBool indefinite);
137 * Calculates the length of the encoded BER data object. This utility
138 * function can be used to calculate how much to allocate space before
139 * encoding with silc_ber_encode.
142 SilcUInt32 silc_ber_encoded_len(SilcUInt32 tag, SilcUInt32 data_len,
143 SilcBool indefinite);
145 #endif /* SILCBER_H */