mirror of https://gerrit.osmocom.org/asn1c
144 lines
3.6 KiB
C
144 lines
3.6 KiB
C
/*-
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* Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#include <constr_TYPE.h>
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#include <assert.h>
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static ssize_t der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len,
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asn_app_consume_bytes_f *cb, void *app_key, int constructed);
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/*
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* The DER encoder of any type.
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*/
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der_enc_rval_t
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der_encode(asn1_TYPE_descriptor_t *type_descriptor, void *struct_ptr,
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asn_app_consume_bytes_f *consume_bytes, void *app_key) {
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ASN_DEBUG("DER encoder invoked for %s",
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type_descriptor->name);
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/*
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* Invoke type-specific encoder.
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*/
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return type_descriptor->der_encoder(type_descriptor,
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struct_ptr, /* Pointer to the destination structure */
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0, 0,
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consume_bytes, app_key);
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}
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/*
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* Write out leading TL[v] sequence according to the type definition.
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*/
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ssize_t
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der_write_tags(asn1_TYPE_descriptor_t *sd,
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size_t struct_length,
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int tag_mode,
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ber_tlv_tag_t tag, /* EXPLICIT or IMPLICIT tag */
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asn_app_consume_bytes_f *cb,
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void *app_key) {
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ber_tlv_tag_t *tags; /* Copy of tags stream */
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int tags_count; /* Number of tags */
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size_t overall_length;
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ssize_t *lens;
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int i;
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if(tag_mode) {
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/*
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* Instead of doing shaman dance like we do in ber_check_tags(),
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* allocate a small array on the stack
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* and initialize it appropriately.
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*/
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tags = alloca((sd->tags_count + (tag_mode?1:0))
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* sizeof(ber_tlv_tag_t));
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if(tags == NULL) return -1; /* Impossible on i386 */
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tags_count = sd->tags_count
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+ 1 /* EXPLICIT or IMPLICIT tag is given */
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- ((tag_mode==-1)?sd->tags_impl_skip:0);
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/* Copy tags over */
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tags[0] = tag;
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for(i = 1; i < tags_count; i++)
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tags[i] = sd->tags[i - 1 + sd->tags_impl_skip];
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} else {
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tags = sd->tags;
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tags_count = sd->tags_count;
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}
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/* No tags to write */
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if(tags_count == 0)
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return 0;
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lens = alloca(tags_count * sizeof(lens[0]));
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if(lens == NULL) return -1;
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/*
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* Array of tags is initialized.
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* Now, compute the size of the TLV pairs, from right to left.
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*/
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overall_length = struct_length;
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for(i = tags_count - 1; i >= 0; --i) {
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lens[i] = der_write_TL(tags[i], overall_length, 0, 0, 0);
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if(lens[i] == -1) return -1;
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overall_length += lens[i];
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lens[i] = overall_length - lens[i];
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}
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if(!cb) return overall_length - struct_length;
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ASN_DEBUG("%s %s TL sequence (%d elements)",
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cb?"Encoding":"Estimating", sd->name, tags_count);
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/*
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* Encode the TL sequence for real.
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*/
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for(i = 0; i < tags_count; i++) {
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ssize_t len;
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int _constr;
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/* If this one happens to be constructed, do it. */
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if(i < (tags_count - 1) || sd->last_tag_form == 1)
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_constr = 1;
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else _constr = 0;
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len = der_write_TL(tags[i], lens[i], cb, app_key, _constr);
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if(len == -1) return -1;
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}
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return overall_length - struct_length;
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}
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static ssize_t
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der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len,
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asn_app_consume_bytes_f *cb, void *app_key,
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int constructed) {
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uint8_t buf[32];
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size_t size = 0;
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int buf_size = cb?sizeof(buf):0;
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ssize_t tmp;
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/* Serialize tag (T from TLV) into possibly zero-length buffer */
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tmp = der_tlv_tag_serialize(tag, buf, buf_size);
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if(tmp == -1 || tmp > (ssize_t)sizeof(buf)) return -1;
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size += tmp;
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/* Serialize length (L from TLV) into possibly zero-length buffer */
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tmp = der_tlv_length_serialize(len, buf+size, buf_size?buf_size-size:0);
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if(tmp == -1) return -1;
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size += tmp;
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if(size > sizeof(buf))
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return -1;
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/*
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* If callback is specified, invoke it, and check its return value.
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*/
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if(cb) {
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if(constructed) *buf |= 0x20;
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if(cb(buf, size, app_key) == -1) {
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return -1;
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}
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}
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return size;
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}
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