Struct ClientHashBuilder 

pub struct ClientHashBuilder { /* private fields */ }

A fast, seeded hasher for short keys.

The default HashMap hasher is SipHash-1-3, chosen for resistance to collision floods. That resistance is not optional here — the key is a client’s source address, which an attacker picks — but SipHash’s cost is out of proportion to a 4-to-17-byte key: with everything else in the client table fixed, callgrind still attributed ~32% of the server’s per-request instructions to hashing one address once.

So this keeps the property and drops the price. The seed is drawn from the OS once per process via RandomState, exactly as SipHash’s keys are, so an attacker cannot compute which addresses collide without first learning a secret they never see. What is given up is SipHash’s proof against an adversary who somehow does learn the seed; what is kept is the practical defence, on a table that is additionally bounded to a fixed capacity with LRU eviction, so even a successful collision attack cannot grow a chain without bound.

Trait Implementations

impl BuildHasher for ClientHashBuilder

type Hasher = ClientHasher

Type of the hasher that will be created.

fn build_hasher(&self) -> ClientHasher

Creates a new hasher.

fn hash_one<T>(&self, x: T) -> u64

where T: Hash, Self: Sized, Self::Hasher: Hasher,

Calculates the hash of a single value.

impl Clone for ClientHashBuilder

fn clone(&self) -> ClientHashBuilder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ClientHashBuilder

impl Default for ClientHashBuilder

fn default() -> Self

Returns the “default value” for a type.