1ASN1_EXTERN_FUNCS(3ossl) OpenSSL ASN1_EXTERN_FUNCS(3ossl)
2
6 ASN1_EXTERN_FUNCS, ASN1_ex_d2i, ASN1_ex_d2i_ex, ASN1_ex_i2d,
7 ASN1_ex_new_func, ASN1_ex_new_ex_func, ASN1_ex_free_func,
8 ASN1_ex_print_func, IMPLEMENT_EXTERN_ASN1 - ASN.1 external function
9 support
10
12 #include <openssl/asn1t.h>
13 typedef int ASN1_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
15 const ASN1_ITEM *it, int tag, int aclass, char opt,
16 ASN1_TLC *ctx);
17 typedef int ASN1_ex_d2i_ex(ASN1_VALUE **pval, const unsigned char **in, long len,
18 const ASN1_ITEM *it, int tag, int aclass, char opt,
19 ASN1_TLC *ctx, OSSL_LIB_CTX *libctx,
20 const char *propq);
21 typedef int ASN1_ex_i2d(const ASN1_VALUE **pval, unsigned char **out,
22 const ASN1_ITEM *it, int tag, int aclass);
23 typedef int ASN1_ex_new_func(ASN1_VALUE **pval, const ASN1_ITEM *it);
24 typedef int ASN1_ex_new_ex_func(ASN1_VALUE **pval, const ASN1_ITEM *it,
25 OSSL_LIB_CTX *libctx, const char *propq);
26 typedef void ASN1_ex_free_func(ASN1_VALUE **pval, const ASN1_ITEM *it);
27 typedef int ASN1_ex_print_func(BIO *out, const ASN1_VALUE **pval,
28 int indent, const char *fname,
29 const ASN1_PCTX *pctx);
30 struct ASN1_EXTERN_FUNCS_st {
32 void *app_data;
33 ASN1_ex_new_func *asn1_ex_new;
34 ASN1_ex_free_func *asn1_ex_free;
35 ASN1_ex_free_func *asn1_ex_clear;
36 ASN1_ex_d2i *asn1_ex_d2i;
37 ASN1_ex_i2d *asn1_ex_i2d;
38 ASN1_ex_print_func *asn1_ex_print;
39 ASN1_ex_new_ex_func *asn1_ex_new_ex;
40 ASN1_ex_d2i_ex *asn1_ex_d2i_ex;
41 };
42 typedef struct ASN1_EXTERN_FUNCS_st ASN1_EXTERN_FUNCS;
43 #define IMPLEMENT_EXTERN_ASN1(sname, tag, fptrs)
45
47 ASN.1 data structures templates are typically defined in OpenSSL using
48 a series of macros such as ASN1_SEQUENCE(), ASN1_SEQUENCE_END() and so
49 on. Instead templates can also be defined based entirely on external
50 functions. These external functions are called to perform operations
51 such as creating a new ASN1_VALUE or converting an ASN1_VALUE to or
52 from DER encoding.
53 The macro IMPLEMENT_EXTERN_ASN1() can be used to create such an
55 externally defined structure. The name of the structure should be
56 supplied in the sname parameter. The tag for the structure (e.g.
57 typically V_ASN1_SEQUENCE) should be supplied in the tag parameter.
58 Finally a pointer to an ASN1_EXTERN_FUNCS structure should be supplied
59 in the fptrs parameter.
60 The ASN1_EXTERN_FUNCS structure has the following entries.
62 app_data
64 A pointer to arbitrary application specific data.
65 asn1_ex_new
67 A "new" function responsible for constructing a new ASN1_VALUE
68 object. The newly constructed value should be stored in *pval. The
69 it parameter is a pointer to the ASN1_ITEM template object created
70 via the IMPLEMENT_EXTERN_ASN1() macro.
71 Returns a positive value on success or 0 on error.
73 asn1_ex_free
75 A "free" function responsible for freeing the ASN1_VALUE passed in
76 *pval that was previously allocated via a "new" function. The it
77 parameter is a pointer to the ASN1_ITEM template object created via
78 the IMPLEMENT_EXTERN_ASN1() macro.
79 asn1_ex_clear
81 A "clear" function responsible for clearing any data in the
82 ASN1_VALUE passed in *pval and making it suitable for reuse. The it
83 parameter is a pointer to the ASN1_ITEM template object created via
84 the IMPLEMENT_EXTERN_ASN1() macro.
85 asn1_ex_d2i
87 A "d2i" function responsible for converting DER data with the tag
88 tag and class class into an ASN1_VALUE. If *pval is non-NULL then
89 the ASN_VALUE it points to should be reused. Otherwise a new
90 ASN1_VALUE should be allocated and stored in *pval. *in points to
91 the DER data to be decoded and len is the length of that data.
92 After decoding *in should be updated to point at the next byte
93 after the decoded data. If the ASN1_VALUE is considered optional in
94 this context then opt will be nonzero. Otherwise it will be zero.
95 The it parameter is a pointer to the ASN1_ITEM template object
96 created via the IMPLEMENT_EXTERN_ASN1() macro. A pointer to the
97 current ASN1_TLC context (which may be required for other ASN1
98 function calls) is passed in the ctx parameter.
99 The asn1_ex_d2i entry may be NULL if asn1_ex_d2i_ex has been
101 specified instead.
102 Returns <= 0 on error or a positive value on success.
104 asn1_ex_i2d
106 An "i2d" function responsible for converting an ASN1_VALUE into DER
107 encoding. On entry *pval will contain the ASN1_VALUE to be
108 encoded. If default tagging is to be used then tag will be -1 on
109 entry. Otherwise if implicit tagging should be used then tag and
110 aclass will be the tag and associated class.
111 If out is not NULL then this function should write the DER encoded
113 data to the buffer in *out, and then increment *out to point to
114 immediately after the data just written.
115 If out is NULL then no data should be written but the length
117 calculated and returned as if it were.
118 The asn1_ex_i2d entry may be NULL if asn1_ex_i2d_ex has been
120 specified instead.
121 The return value should be negative if a fatal error occurred, or 0
123 if a non-fatal error occurred. Otherwise it should return the
124 length of the encoded data.
125 asn1_ex_print
127 A "print" function. out is the BIO to print the output to. *pval is
128 the ASN1_VALUE to be printed. indent is the number of spaces of
129 indenting to be printed before any data is printed. fname is
130 currently unused and is always "". pctx is a pointer to the
131 ASN1_PCTX for the print operation.
132 Returns 0 on error or a positive value on success. If the return
134 value is 2 then an additional newline will be printed after the
135 data printed by this function.
136 asn1_ex_new_ex
138 This is the same as asn1_ex_new except that it is additionally
139 passed the OSSL_LIB_CTX to be used in libctx and any property query
140 string to be used for algorithm fetching in the propq parameter.
141 See "ALGORITHM FETCHING" in crypto(7) for further details. If
142 asn1_ex_new_ex is non NULL, then it will always be called in
143 preference to asn1_ex_new.
144 asn1_ex_d2i_ex
146 This is the same as asn1_ex_d2i except that it is additionally
147 passed the OSSL_LIB_CTX to be used in libctx and any property query
148 string to be used for algorithm fetching in the propq parameter.
149 See "ALGORITHM FETCHING" in crypto(7) for further details. If
150 asn1_ex_d2i_ex is non NULL, then it will always be called in
151 preference to asn1_ex_d2i.
152
154 Return values for the various callbacks are as described above.
155
157 ASN1_item_new_ex(3)
158
160 The asn1_ex_new_ex and asn1_ex_d2i_ex callbacks were added in OpenSSL
161 3.0.
162
164 Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.
165 Licensed under the Apache License 2.0 (the "License"). You may not use
167 this file except in compliance with the License. You can obtain a copy
168 in the file LICENSE in the source distribution or at
169 <https://www.openssl.org/source/license.html>.
1703.0.9 2023-07-27 ASN1_EXTERN_FUNCS(3ossl)