--- /dev/null
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include <asn_internal.h>
+#include <errno.h>
+
+static ssize_t der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len,
+ asn_app_consume_bytes_f *cb, void *app_key, int constructed);
+
+/*
+ * The DER encoder of any type.
+ */
+asn_enc_rval_t
+der_encode(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr,
+ asn_app_consume_bytes_f *consume_bytes, void *app_key) {
+
+ ASN_DEBUG("DER encoder invoked for %s",
+ type_descriptor->name);
+
+ /*
+ * Invoke type-specific encoder.
+ */
+ return type_descriptor->der_encoder(type_descriptor,
+ struct_ptr, /* Pointer to the destination structure */
+ 0, 0,
+ consume_bytes, app_key);
+}
+
+/*
+ * Argument type and callback necessary for der_encode_to_buffer().
+ */
+typedef struct enc_to_buf_arg {
+ void *buffer;
+ size_t left;
+} enc_to_buf_arg;
+static int encode_to_buffer_cb(const void *buffer, size_t size, void *key) {
+ enc_to_buf_arg *arg = (enc_to_buf_arg *)key;
+
+ if(arg->left < size)
+ return -1; /* Data exceeds the available buffer size */
+
+ memcpy(arg->buffer, buffer, size);
+ arg->buffer = ((char *)arg->buffer) + size;
+ arg->left -= size;
+
+ return 0;
+}
+
+/*
+ * A variant of the der_encode() which encodes the data into the provided buffer
+ */
+asn_enc_rval_t
+der_encode_to_buffer(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr,
+ void *buffer, size_t buffer_size) {
+ enc_to_buf_arg arg;
+ asn_enc_rval_t ec;
+
+ arg.buffer = buffer;
+ arg.left = buffer_size;
+
+ ec = type_descriptor->der_encoder(type_descriptor,
+ struct_ptr, /* Pointer to the destination structure */
+ 0, 0, encode_to_buffer_cb, &arg);
+ if(ec.encoded != -1) {
+ assert(ec.encoded == (ssize_t)(buffer_size - arg.left));
+ /* Return the encoded contents size */
+ }
+ return ec;
+}
+
+
+/*
+ * Write out leading TL[v] sequence according to the type definition.
+ */
+ssize_t
+der_write_tags(asn_TYPE_descriptor_t *sd,
+ size_t struct_length,
+ int tag_mode, int last_tag_form,
+ ber_tlv_tag_t tag, /* EXPLICIT or IMPLICIT tag */
+ asn_app_consume_bytes_f *cb,
+ void *app_key) {
+ ber_tlv_tag_t *tags; /* Copy of tags stream */
+ int tags_count; /* Number of tags */
+ size_t overall_length;
+ ssize_t *lens;
+ int i;
+
+ ASN_DEBUG("Writing tags (%s, tm=%d, tc=%d, tag=%s, mtc=%d)",
+ sd->name, tag_mode, sd->tags_count,
+ ber_tlv_tag_string(tag),
+ tag_mode
+ ?(sd->tags_count+1
+ -((tag_mode == -1) && sd->tags_count))
+ :sd->tags_count
+ );
+
+ if(tag_mode) {
+ /*
+ * Instead of doing shaman dance like we do in ber_check_tags(),
+ * allocate a small array on the stack
+ * and initialize it appropriately.
+ */
+ int stag_offset;
+ tags = (ber_tlv_tag_t *)alloca((sd->tags_count + 1) * sizeof(ber_tlv_tag_t));
+ if(!tags) { /* Can fail on !x86 */
+ errno = ENOMEM;
+ return -1;
+ }
+ tags_count = sd->tags_count
+ + 1 /* EXPLICIT or IMPLICIT tag is given */
+ - ((tag_mode == -1) && sd->tags_count);
+ /* Copy tags over */
+ tags[0] = tag;
+ stag_offset = -1 + ((tag_mode == -1) && sd->tags_count);
+ for(i = 1; i < tags_count; i++)
+ tags[i] = sd->tags[i + stag_offset];
+ } else {
+ tags = sd->tags;
+ tags_count = sd->tags_count;
+ }
+
+ /* No tags to write */
+ if(tags_count == 0)
+ return 0;
+
+ lens = (ssize_t *)alloca(tags_count * sizeof(lens[0]));
+ if(!lens) {
+ errno = ENOMEM;
+ return -1;
+ }
+
+ /*
+ * Array of tags is initialized.
+ * Now, compute the size of the TLV pairs, from right to left.
+ */
+ overall_length = struct_length;
+ for(i = tags_count - 1; i >= 0; --i) {
+ lens[i] = der_write_TL(tags[i], overall_length, 0, 0, 0);
+ if(lens[i] == -1) return -1;
+ overall_length += lens[i];
+ lens[i] = overall_length - lens[i];
+ }
+
+ if(!cb) return overall_length - struct_length;
+
+ ASN_DEBUG("%s %s TL sequence (%d elements)",
+ cb?"Encoding":"Estimating", sd->name, tags_count);
+
+ /*
+ * Encode the TL sequence for real.
+ */
+ for(i = 0; i < tags_count; i++) {
+ ssize_t len;
+ int _constr;
+
+ /* Check if this tag happens to be constructed */
+ _constr = (last_tag_form || i < (tags_count - 1));
+
+ len = der_write_TL(tags[i], lens[i], cb, app_key, _constr);
+ if(len == -1) return -1;
+ }
+
+ return overall_length - struct_length;
+}
+
+static ssize_t
+der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len,
+ asn_app_consume_bytes_f *cb, void *app_key,
+ int constructed) {
+ uint8_t buf[32];
+ size_t size = 0;
+ int buf_size = cb?sizeof(buf):0;
+ ssize_t tmp;
+
+ /* Serialize tag (T from TLV) into possibly zero-length buffer */
+ tmp = ber_tlv_tag_serialize(tag, buf, buf_size);
+ if(tmp == -1 || tmp > (ssize_t)sizeof(buf)) return -1;
+ size += tmp;
+
+ /* Serialize length (L from TLV) into possibly zero-length buffer */
+ tmp = der_tlv_length_serialize(len, buf+size, buf_size?buf_size-size:0);
+ if(tmp == -1) return -1;
+ size += tmp;
+
+ if(size > sizeof(buf))
+ return -1;
+
+ /*
+ * If callback is specified, invoke it, and check its return value.
+ */
+ if(cb) {
+ if(constructed) *buf |= 0x20;
+ if(cb(buf, size, app_key) < 0)
+ return -1;
+ }
+
+ return size;
+}
git.stg.codes / stg.git / blobdiff