push-packet 0.1.0

//! Defines [`Engine`] traits.
#[cfg(feature = "linear")]
pub mod linear;

use crate::{
    error::Error,
    loader::Loader,
    rules::{Rule, RuleId},
};

/// The Engine trait defines how rules are evaluated in the eBPF program. Each Engine requires a
/// matching eBPF program.
pub trait Engine {
    /// A type corresponding to the [`Engine`]'s [`Loader`]. This is responsible for collecting
    /// configuration and generating the [`Engine`].
    type Loader: Loader<Component = Self> + Default;
    /// The raw bytes of the eBPF program
    const EBPF_BYTES: &'static [u8];

    /// The eBPF program name
    const EBPF_PROGRAM_NAME: &'static str;

    /// If this engnine is limited in max capacity, return the capcacity
    fn capacity(&self) -> Option<usize>;
    /// Add a rule to the engine
    ///
    /// # Errors
    /// Returns [`Error::EngineAtCapacity`] if the engine cannot accept additional rules.
    /// Returns additional errors depending on the engine implementation.
    fn add_rule(&mut self, rule_id: RuleId, rule: &Rule) -> Result<(), Error>;
    /// Remove a rule from the engine
    ///
    /// # Errors
    /// Returns [`Error::MissingRule`] if the rule id is not present in the filter.
    /// Returns additional errors depending on the engine implementation.
    fn remove_rule(&mut self, rule_id: RuleId, rule: &Rule) -> Result<(), Error>;
}