Struct BufferRef 

pub struct BufferRef<FeatureData>(/* private fields */);

Reference to a VPP buffer

A &mut BufferRef<FeatureData> is equivalent to a vlib_buffer_t * in C (a *mut vlib_buffer_t in Rust).

Implementations

impl<FeatureData> BufferRef<FeatureData>

pub unsafe fn from_ptr<'a>(ptr: *mut vlib_buffer_t) -> &'a Self

Create a &BufferRef from a raw pointer

Safety

• The pointer must be a valid and properly initialised vlib_buffer_t.
• The pointer must stay valid and the contents must not be mutated for the duration of the lifetime of the returned object.

pub unsafe fn from_ptr_mut<'a>(ptr: *mut vlib_buffer_t) -> &'a mut Self

Create a &mut BufferRef from a raw pointer

Safety

• The pointer must be a valid and properly initialised vlib_buffer_t.
• The pointer must stay valid and the contents must not be mutated for the duration of the lifetime of the returned object.

pub fn as_ptr(&self) -> *mut vlib_buffer_t

Returns the raw pointer to the underlying vlib_buffer_t

pub fn current_length(&self) -> u16

Current length

Typically, this is the amount of packet data remaining from Self::current_ptr_mut.

pub fn flags(&self) -> BufferFlags

Buffer flags

pub fn current_ptr_mut(&mut self) -> *mut u8

Get a pointer to the current data

This corresponds to the VPP C API vlib_buffer_get_current.

Usage guidance

Note that the pointer returned may point to uninitialised data depending on the context. In addition, depending on the context, the remaining data the amount is expected. Finally, remaining data is sufficent and it’s initialised it may not have been validated so care must be taken in determining whether or not lengths in the headers can be trusted.

pub fn has_space(&self, l: i16) -> bool

Check if the buffer has space for l more bytes

pub unsafe fn advance(&mut self, l: i16)

Advance the current data pointer by l bytes

Safety

• If l is positive, the buffer must have at least l bytes of data remaining.
• If l is negative, the current data offset must be at least -l bytes from the start of the buffer’s data area (including pre-data).

pub fn tail_mut(&mut self) -> *mut u8

Get a pointer to the end of the current data

This corresponds to the VPP C function vlib_buffer_get_tail.

pub fn add_trace<N: Node>( &mut self, vm: &MainRef, node: &NodeRuntimeRef<N>, ) -> &mut MaybeUninit<N::TraceData>

Add trace data to this buffer

pub fn set_error<N: Node>(&mut self, node: &NodeRuntimeRef<N>, error: N::Errors)

Set an error reason

This is typically done before sending the packet to the drop node, where it use the value to display the reason in traces and automatically increment the per-node, per-error counter for the error.

impl<FeatureData> BufferRef<FeatureData>

pub fn vnet_buffer(&self) -> &BufferRef

pub fn vnet_buffer_mut(&mut self) -> &mut BufferRef

impl<FeatureData: Copy> BufferRef<FeatureData>

pub unsafe fn vnet_feature_next(&mut self) -> (u32, FeatureData)

Get the next feature node and feature data for this buffer

Used when continuing to the next feature node in a node invoked from a feature arc.

Safety

Must only be used from nodes when invoked from a feature arc.