Function esp_idf_svc::sys::mbedtls_asn1_traverse_sequence_of

pub unsafe extern "C" fn mbedtls_asn1_traverse_sequence_of(
    p: *mut *mut u8,
    end: *const u8,
    tag_must_mask: u8,
    tag_must_val: u8,
    tag_may_mask: u8,
    tag_may_val: u8,
    cb: Option<unsafe extern "C" fn(_: *mut c_void, _: i32, _: *mut u8, _: usize) -> i32>,
    ctx: *mut c_void,
) -> i32

\brief Traverse an ASN.1 SEQUENCE container and call a callback for each entry.

This function checks that the input is a SEQUENCE of elements that each have a “must” tag, and calls a callback function on the elements that have a “may” tag.

For example, to validate that the input is a SEQUENCE of tag1 and call cb on each element, use

mbedtls_asn1_traverse_sequence_of(&p, end, 0xff, tag1, 0, 0, cb, ctx);

To validate that the input is a SEQUENCE of ANY and call cb on each element, use

mbedtls_asn1_traverse_sequence_of(&p, end, 0, 0, 0, 0, cb, ctx);

To validate that the input is a SEQUENCE of CHOICE {NULL, OCTET STRING} and call cb on each element that is an OCTET STRING, use

mbedtls_asn1_traverse_sequence_of(&p, end, 0xfe, 0x04, 0xff, 0x04, cb, ctx);

The callback is called on the elements with a “may” tag from left to right. If the input is not a valid SEQUENCE of elements with a “must” tag, the callback is called on the elements up to the leftmost point where the input is invalid.

\warning This function is still experimental and may change at any time.

\param p The address of the pointer to the beginning of the ASN.1 SEQUENCE header. This is updated to point to the end of the ASN.1 SEQUENCE container on a successful invocation. \param end The end of the ASN.1 SEQUENCE container. \param tag_must_mask A mask to be applied to the ASN.1 tags found within the SEQUENCE before comparing to \p tag_must_val. \param tag_must_val The required value of each ASN.1 tag found in the SEQUENCE, after masking with \p tag_must_mask. Mismatching tags lead to an error. For example, a value of \c 0 for both \p tag_must_mask and \p tag_must_val means that every tag is allowed, while a value of \c 0xFF for \p tag_must_mask means that \p tag_must_val is the only allowed tag. \param tag_may_mask A mask to be applied to the ASN.1 tags found within the SEQUENCE before comparing to \p tag_may_val. \param tag_may_val The desired value of each ASN.1 tag found in the SEQUENCE, after masking with \p tag_may_mask. Mismatching tags will be silently ignored. For example, a value of \c 0 for \p tag_may_mask and \p tag_may_val means that any tag will be considered, while a value of \c 0xFF for \p tag_may_mask means that all tags with value different from \p tag_may_val will be ignored. \param cb The callback to trigger for each component in the ASN.1 SEQUENCE that matches \p tag_may_val. The callback function is called with the following parameters: - \p ctx. - The tag of the current element. - A pointer to the start of the current element’s content inside the input. - The length of the content of the current element. If the callback returns a non-zero value, the function stops immediately, forwarding the callback’s return value. \param ctx The context to be passed to the callback \p cb.

\return \c 0 if successful the entire ASN.1 SEQUENCE was traversed without parsing or callback errors. \return #MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains extra data after a valid SEQUENCE of elements with an accepted tag. \return #MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the input starts with an ASN.1 SEQUENCE in which an element has a tag that is not accepted. \return An ASN.1 error code if the input does not start with a valid ASN.1 SEQUENCE. \return A non-zero error code forwarded from the callback \p cb in case the latter returns a non-zero value.