ASN.1: Add ASN.1 SEQUENCE traversal API
diff --git a/library/asn1parse.c b/library/asn1parse.c
index 3105d32..8506b49 100644
--- a/library/asn1parse.c
+++ b/library/asn1parse.c
@@ -248,6 +248,58 @@
}
/*
+ * Traverse an ASN.1 "SEQUENCE OF <tag>"
+ * and call a callback for each entry found.
+ */
+int mbedtls_asn1_traverse_sequence_of(
+ unsigned char **p,
+ const unsigned char *end,
+ uint8_t tag_must_mask, uint8_t tag_must_val,
+ uint8_t tag_may_mask, uint8_t tag_may_val,
+ int (*cb)( void *ctx, int tag,
+ unsigned char *start, size_t len ),
+ void *ctx )
+{
+ int ret;
+ size_t len;
+
+ /* Get main sequence tag */
+ if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
+ MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
+ {
+ return( ret );
+ }
+
+ if( *p + len != end )
+ return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
+
+ while( *p < end )
+ {
+ unsigned char const tag = *(*p)++;
+
+ if( ( tag & tag_must_mask ) != tag_must_val )
+ return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
+
+ if( ( ret = mbedtls_asn1_get_len( p, end, &len ) ) != 0 )
+ return( ret );
+
+ if( ( tag & tag_may_mask ) == tag_may_val )
+ {
+ if( cb != NULL )
+ {
+ ret = cb( ctx, tag, *p, len );
+ if( ret != 0 )
+ return( ret );
+ }
+ }
+
+ *p += len;
+ }
+
+ return( 0 );
+}
+
+/*
* Get a bit string without unused bits
*/
int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,