EffectiveMss

netstack3_base

Struct EffectiveMss 

Source 
pub struct EffectiveMss { /* private fields */ }
Expand description

Like Mss, but smaller to account for fixed-size TCP Options.

This corresponds to the “effective send MSS” as defined in RFC 9293 section 3.7.1: Eff.snd.MSS = min(SendMSS+20, MMS_S) - TCPhdrsize - IPoptionsize where: […] * TCPhdrsize is the size of the fixed TCP header and any options.

Both Mss and EffectiveMss have their place in TCP. For example, the TCP MSS option has Mss semantics, while the MSS used to calculate receive windows & congestion windows has EffectiveMss semantics. When implementing a TCP feature, refer to the feature’s RFC to determine which MSS semantics are appropriate to use.

Note: this implementation accounts for all fixed-sized TCP Options that are part of SegmentOptions. SACK blocks are ignored, because they are variable sized. Variable sized options pose a problem when calculating the EffectiveMss because they vary from segment to segment, whereas the EffectiveMss should be stable throughout the lifetime of the connection. While, no RFC explicitly states how to account for variable sized options, we take inspiration from Linux’s TCP implementation and choose to ignore them until it comes time to actually calculate payload sizes for a given segment.

Implementations§

Source§

impl EffectiveMss

Source

pub const fn from_mss(mss: Mss, size_limits: MssSizeLimiters) -> Self

Constructs an EffectiveMss from an Mss

Source

pub fn payload_size(&self, options: &SegmentOptions) -> NonZeroU16

Computes the amount of payload data to include in a segment.

Accounts for the size of any variable-sized options present in the segment.

Source

pub fn mss(&self) -> &Mss

Returns the original Mss used to compute this EffectiveMss.

Source

pub fn update_mss(&mut self, new: Mss)

Replaces the held Mss with a new value.

Source

pub const fn get(&self) -> u16

Gets the numeric value of the MSS.

Trait Implementations§

Source§

impl Clone for EffectiveMss

Source§

fn clone(&self) -> EffectiveMss

Returns a duplicate of the value. Read more
1.0.0 · Source§

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

Performs copy-assignment from source. Read more
Source§

impl Debug for EffectiveMss

Source§

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

Formats the value using the given formatter. Read more
Source§

impl From<EffectiveMss> for u32

Source§

fn from(mss: EffectiveMss) -> Self

Converts to this type from the input type.
Source§

impl From<EffectiveMss> for usize

Source§

fn from(mss: EffectiveMss) -> Self

Converts to this type from the input type.
Source§

impl PartialEq for EffectiveMss

Source§

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

Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§

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

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

impl Copy for EffectiveMss

Source§

impl Eq for EffectiveMss

Source§

impl StructuralPartialEq for EffectiveMss

Auto Trait Implementations§

Blanket Implementations§

Source§

impl<T> Any for T
where T: 'static + ?Sized,

Source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
Source§

impl<T> Borrow<T> for T
where T: ?Sized,

Source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

Source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
Source§

impl<T> CloneToUninit for T
where T: Clone,

Source§

unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
Source§

impl<T> DynClone for T
where T: Clone,

Source§

fn __clone_box(&self, _: Private) -> *mut ()

§

impl<T, D> Encode<Ambiguous1, D> for T
where D: ResourceDialect,

§

unsafe fn encode( self, _encoder: &mut Encoder<'_, D>, _offset: usize, _depth: Depth, ) -> Result<(), Error>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID. Read more
§

impl<T, D> Encode<Ambiguous2, D> for T
where D: ResourceDialect,

§

unsafe fn encode( self, _encoder: &mut Encoder<'_, D>, _offset: usize, _depth: Depth, ) -> Result<(), Error>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID. Read more
Source§

impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

Source§

fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
Source§

impl<T> From<T> for T

Source§

fn from(t: T) -> T

Returns the argument unchanged.

Source§

impl<T, U> Into<U> for T
where U: From<T>,

Source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Source§

impl<T> IntoEither for T

Source§

fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
Source§

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
§

impl<T> Pointable for T

§

const ALIGN: usize

The alignment of pointer.
§

type Init = T

The type for initializers.
§

unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
§

unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
§

unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
§

unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
Source§

impl<CC, BC, Meta> RecvFrameContext<Meta, BC> for CC
where Meta: ReceivableFrameMeta<CC, BC>,

Source§

fn receive_frame<B>(&mut self, bindings_ctx: &mut BC, metadata: Meta, frame: B)
where B: BufferMut + Debug,

Receive a frame. Read more
Source§

impl<CC, BC, Meta> SendFrameContext<BC, Meta> for CC
where Meta: SendableFrameMeta<CC, BC>,

Source§

fn send_frame<S>( &mut self, bindings_ctx: &mut BC, metadata: Meta, frame: S, ) -> Result<(), ErrorAndSerializer<SendFrameErrorReason, S>>
where S: Serializer, <S as Serializer>::Buffer: BufferMut,

Send a frame. Read more
Source§

impl<BC, S, Meta, DeviceId> SendableFrameMeta<FakeCoreCtx<S, Meta, DeviceId>, BC> for Meta

Source§

fn send_meta<SS>( self, core_ctx: &mut FakeCoreCtx<S, Meta, DeviceId>, bindings_ctx: &mut BC, frame: SS, ) -> Result<(), ErrorAndSerializer<SendFrameErrorReason, SS>>
where SS: Serializer, <SS as Serializer>::Buffer: BufferMut,

Sends this frame metadata to the provided contexts.
Source§

impl<Meta, BC> SendableFrameMeta<FakeFrameCtx<Meta>, BC> for Meta

Source§

fn send_meta<S>( self, core_ctx: &mut FakeFrameCtx<Meta>, _bindings_ctx: &mut BC, frame: S, ) -> Result<(), ErrorAndSerializer<SendFrameErrorReason, S>>
where S: Serializer, <S as Serializer>::Buffer: BufferMut,

Sends this frame metadata to the provided contexts.
Source§

impl<Id, CC, BC> TimerHandler<BC, Id> for CC
where BC: TimerBindingsTypes, Id: HandleableTimer<CC, BC>,

Source§

fn handle_timer( &mut self, bindings_ctx: &mut BC, dispatch: Id, timer: <BC as TimerBindingsTypes>::UniqueTimerId, )

Handle a timer firing. Read more
Source§

impl<T> ToOwned for T
where T: Clone,

Source§

type Owned = T

The resulting type after obtaining ownership.
Source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
Source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
Source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

Source§

type Error = Infallible

The type returned in the event of a conversion error.
Source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
Source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

Source§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
Source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
§

impl<L, T> UnlockedAccess<L> for T
where L: UnlockedAccessMarkerFor<T>,

§

type Data = <L as UnlockedAccessMarkerFor<T>>::Data

The type of state being accessed.
§

type Guard<'l> = &'l <L as UnlockedAccessMarkerFor<T>>::Data where T: 'l

A guard providing read access to the data.
§

fn access(&self) -> <T as UnlockedAccess<L>>::Guard<'_>

How to access the state.
§

impl<V, T> VZip<V> for T
where V: MultiLane<T>,

§

fn vzip(self) -> V

§

impl<B, A> LockBefore<B> for A
where B: LockAfter<A>,

Source§

impl<T> TestOnlyPartialEq for T
where T: PartialEq,