Struct RateLimitConfig 

#[non_exhaustive]
pub struct RateLimitConfig {
    pub max_attempts_per_minute: u32,
    pub pre_auth_max_per_minute: Option<u32>,
    pub max_tracked_keys: usize,
    pub idle_eviction: Duration,
}

Rate limiting configuration for authentication attempts.

rmcp-server-kit uses two independent per-IP token-bucket limiters for auth:

1. Pre-auth abuse gate (Self::pre_auth_max_per_minute): consulted before any password-hash work. Throttles unauthenticated traffic from a single source IP so an attacker cannot pin the CPU on Argon2id by spraying invalid bearer tokens. Sized generously (default = 10× the post-failure quota) so legitimate clients are unaffected. mTLS- authenticated connections bypass this gate entirely (the TLS handshake already performed expensive crypto with a verified peer).
2. Post-failure backoff (Self::max_attempts_per_minute): consulted after an authentication attempt fails. Provides explicit backpressure on bad credentials.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

max_attempts_per_minute: u32

Maximum failed authentication attempts per source IP per minute. Successful authentications do not consume this budget.

pre_auth_max_per_minute: Option<u32>

Maximum unauthenticated requests per source IP per minute admitted to the password-hash verification path. When None, defaults to max_attempts_per_minute * 10 at limiter-construction time.

Set higher than Self::max_attempts_per_minute so honest clients retrying with the wrong key never trip this gate; its purpose is only to bound CPU usage under spray attacks.

max_tracked_keys: usize

Hard cap on the number of distinct source IPs tracked per limiter. When reached, idle entries are pruned first; if still full, the oldest (LRU) entry is evicted to make room for the new one. This bounds memory under IP-spray attacks. Default: 10_000.

idle_eviction: Duration

Per-IP entries idle for longer than this are eligible for opportunistic pruning. Default: 15 minutes.

Implementations

impl RateLimitConfig

pub fn new(max_attempts_per_minute: u32) -> Self

Create a rate limit config with the given max failed attempts per minute. Pre-auth gate defaults to 10x this value at limiter-construction time. Memory-bound defaults are 10_000 tracked keys with 15-minute idle eviction.

pub fn with_pre_auth_max_per_minute(self, quota: u32) -> Self

Override the pre-auth abuse-gate quota (per source IP per minute). When unset, defaults to max_attempts_per_minute * 10.

pub fn with_max_tracked_keys(self, max: usize) -> Self

Override the per-limiter cap on tracked source-IP keys (default 10_000).

pub fn with_idle_eviction(self, idle: Duration) -> Self

Override the idle-eviction window (default 15 minutes).

Trait Implementations

impl Clone for RateLimitConfig

fn clone(&self) -> RateLimitConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RateLimitConfig

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

Formats the value using the given formatter.

impl Default for RateLimitConfig

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for RateLimitConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.