Struct Attribute 

pub struct Attribute {
    pub len: u16,
    pub type_: u16,
}

Represents a netlink attribute with type-length-value (TLV) format

Netlink attributes use a TLV format where each attribute consists of:

• A length field (including header and payload)
• A type field (which may include flags like NESTED and NET_BYTEORDER)
• A variable-length payload

Fields

len: u16

type_: u16

Implementations

impl Attribute

pub const NESTED: i32

Flag bit indicating a nested attribute

pub const NET_BYTEORDER: i32

Flag bit indicating the attribute value is in network byte order

pub const TYPE_MASK: i32

Mask to extract the attribute type without flag bits

pub const ALIGNTO: usize = 4

Alignment size for netlink attributes (4 bytes)

pub const HDRLEN: usize

Size of attribute header, aligned to ALIGNTO boundary

pub const data_type_len: [usize; 5]

Size lookup table for standard data types

pub const fn new() -> Self

Creates a new empty attribute

Returns

A zeroed attribute structure

pub const fn align(len: usize) -> usize

Aligns a length to the attribute alignment boundary

This ensures proper memory alignment for netlink attributes.

Parameters

• len - The length to align

Returns

The length aligned to ALIGNTO boundary

pub fn is_empty(&self) -> bool

Checks if the attribute is empty (all bytes are zero)

Used to determine if the attribute has been initialized or reset.

Returns

true if all bytes in the attribute are zero, false otherwise

pub fn reset(&mut self)

Clears the attribute by zeroing its memory

Resets all bytes of the attribute to zero, effectively clearing it. Does nothing if the attribute is already empty.

pub fn for_each(&mut self, nlh: &mut Header, offset: usize)

Iterates through all attributes in a netlink message

Provides access to each attribute within the message payload.

Parameters

• nlh - Netlink message header containing the attributes
• offset - Offset in bytes from the start of the payload to the first attribute

pub fn for_each_nested(&mut self) -> *mut Self

Iterates through attributes in a nested attribute

Provides access to each attribute within a nested attribute.

Returns

Pointer to the first attribute within the nested attribute

Panics

In debug mode, panics if this attribute is not a nested attribute

pub fn for_each_payload(&mut self, payload_size: usize) -> *mut Self

Iterates through attributes in a raw payload buffer

Used when processing a raw buffer containing netlink attributes.

Parameters

• payload_size - Size in bytes of the payload buffer

Returns

Pointer to the first attribute in the payload

pub fn get_type(&self) -> u16

Gets the attribute type value without flag bits

Returns

The attribute type with the NESTED and NET_BYTEORDER flag bits masked out

pub fn len(&self) -> u16

Gets the total length of the netlink attribute

Returns

The total length of the attribute in bytes, including header and payload

pub fn get_payload_len(&self) -> u16

Gets the length of the attribute payload (value part)

Returns

The length of the attribute payload in bytes

pub fn get_payload(&self) -> *mut ()

Gets pointer to the attribute payload

Returns

A mutable pointer to the attribute’s payload (value part)

pub fn is_ok(&self, len: i32) -> bool

Checks if there is room for an attribute in a buffer

Verifies that a buffer containing an attribute has enough space for the attribute, ensuring it is neither malformed nor truncated.

Parameters

• len - The length of the buffer in bytes

Returns

true if the attribute fits within the buffer, false otherwise

pub fn next(&self) -> *mut Self

Gets the next attribute in a sequence

Returns

A pointer to the next attribute in a sequence, accounting for alignment

pub fn type_valid(&self, max: u16) -> i32

Verifies if the attribute type is within the supported range

Parameters

• max - The maximum valid attribute type value

Returns

0 on error, 1 on success

pub fn __validate(&self, type_: DataType, exp_len: usize) -> i32

Internal validation function for netlink attributes

Parameters

• type_ - The expected data type of the attribute
• exp_len - The expected length of the attribute payload

Returns

0 on success, negative error code on failure

pub fn validate(&self, type_: DataType) -> i32

Validates a netlink attribute against its expected data type

Ensures that integer attributes have sufficient space allocated.

Parameters

• type_ - The expected data type of the attribute

Returns

0 on success, negative error code on failure

Panics

In debug mode, panics if the attribute has zero length

pub fn validate2(&self, type_: DataType, exp_len: usize) -> i32

Extended validation for attributes with variable size

Allows more precise validation for attributes with variable data sizes.

Parameters

• type_ - The expected data type of the attribute
• exp_len - The expected length of the attribute payload

Returns

0 on success, negative error code on failure

pub fn parse( nlh: &mut Header, offset: u32, cb: attr_callback_t, data: *mut u8, ) -> i32

Parses attributes in a netlink message

Iterates over the sequence of attributes in the message, calling the provided callback function for each attribute.

Parameters

• nlh - Netlink message header containing attributes to parse
• offset - Offset in bytes from the start of the payload to the first attribute
• cb - Callback function to call for each attribute
• data - User data to pass to the callback function

Returns

Status code from the last callback, or error code

pub fn parse_nested(&mut self, cb: attr_callback_t, data: *mut u8) -> i32

Parses attributes inside a nested attribute

Processes attributes contained within a nested attribute, calling the provided callback for each one.

Parameters

• cb - Callback function to call for each attribute
• data - User data to pass to the callback function

Returns

Status code from the last callback, or error code

pub fn parse_payload( &mut self, payload_len: usize, cb: attr_callback_t, data: *mut u8, ) -> i32

Parses attributes in a raw payload buffer

Processes attributes contained within a raw buffer, calling the provided callback for each one.

Parameters

• payload_len - Length of the payload in bytes
• cb - Callback function to call for each attribute
• data - User data to pass to the callback function

Returns

Status code from the last callback, or error code

pub fn get_u8(&self) -> u8

Gets the 8-bit unsigned integer value from an attribute

Returns

The 8-bit unsigned integer value contained in the attribute

pub fn get_u16(&self) -> u16

Gets the 16-bit unsigned integer value from an attribute

Reads the value in an alignment-safe manner.

Returns

The 16-bit unsigned integer value contained in the attribute

pub fn get_u32(&self) -> u32

Gets the 32-bit unsigned integer value from an attribute

Returns

The 32-bit unsigned integer value contained in the attribute

pub fn get_u64(&self) -> u64

Gets the 64-bit unsigned integer value from an attribute

Reads the value in an alignment-safe manner.

Returns

The 64-bit unsigned integer value contained in the attribute

pub fn get_uint(&self) -> u64

Gets a variable-sized integer from an attribute

Handles attributes containing 8-bit, 16-bit, 32-bit, or 64-bit integers.

Returns

The integer value as a u64, regardless of the actual size

pub fn get_str(&self) -> *const i8

Gets a pointer to the string value in an attribute

Returns

A pointer to the C-style string contained in the attribute

pub fn put(nlh: &mut Header, type_: u16, len: usize, data: *const u8)

Adds an attribute to a netlink message

Updates the length field of the message by adding the size of the new attribute.

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• len - Length of the attribute payload in bytes
• data - Pointer to the attribute payload data

pub fn put_u8(nlh: &mut Header, type_: u16, data: u8)

Adds an 8-bit unsigned integer attribute to a netlink message

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• data - The 8-bit unsigned integer value to add

pub fn put_u16(nlh: &mut Header, type_: u16, data: u16)

Adds a 16-bit unsigned integer attribute to a netlink message

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• data - The 16-bit unsigned integer value to add

pub fn put_u32(nlh: &mut Header, type_: u16, data: u32)

Adds a 32-bit unsigned integer attribute to a netlink message

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• data - The 32-bit unsigned integer value to add

pub fn put_u64(nlh: &mut Header, type_: u16, data: u64)

Adds a 64-bit unsigned integer attribute to a netlink message

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• data - The 64-bit unsigned integer value to add

pub fn put_str(nlh: &mut Header, type_: u16, data: *const i8)

Adds a string attribute to a netlink message

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• data - Pointer to the null-terminated string to add

pub fn put_strz(nlh: &mut Header, type_: u16, data: *const i8)

Adds a null-terminated string attribute to a netlink message

Parameters

• nlh - Netlink message header to add the attribute to
• type_ - Type of the attribute
• data - Pointer to the string to add (null terminator will be included)

pub fn nest_start(nlh: &mut Header, type_: u16) -> *mut Self

Starts a nested attribute in a netlink message

Returns a pointer to the nested attribute header for later use.

Parameters

• nlh - Netlink message header to add the nested attribute to
• type_ - Type of the attribute with the NESTED flag set

Returns

Pointer to the nested attribute, to be used with nest_end or nest_cancel

pub fn nest_end(nlh: &mut Header, start: *mut Self)

Finalizes a nested attribute by updating its length

Parameters

• nlh - Netlink message header containing the nested attribute
• start - Pointer to the nested attribute as returned by nest_start

pub fn nest_cancel(nlh: &mut Header, start: *mut Self)

Cancels a nested attribute by rolling back the message length

Parameters

• nlh - Netlink message header containing the nested attribute
• start - Pointer to the nested attribute as returned by nest_start

Trait Implementations

impl Clone for Attribute

fn clone(&self) -> Attribute

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Attribute

impl Debug for Attribute

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Attribute

impl Hash for Attribute

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Attribute

fn cmp(&self, other: &Attribute) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Attribute

fn eq(&self, other: &Attribute) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Attribute

fn partial_cmp(&self, other: &Attribute) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for Attribute