// Copyright 2019 Parity Technologies (UK) Ltd.
//
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//
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//! [Noise protocol framework][noise] support for libp2p.
//!
//! This crate provides `libp2p_core::InboundUpgrade` and `libp2p_core::OutboundUpgrade`
//! implementations for various noise handshake patterns (currently IK, IX, and XX)
//! over a particular choice of DH key agreement (currently only X25519).
//!
//! All upgrades produce as output a pair, consisting of the remote's static public key
//! and a `NoiseOutput` which represents the established cryptographic session with the
//! remote, implementing `tokio_io::AsyncRead` and `tokio_io::AsyncWrite`.
//!
//! # Usage
//!
//! Example:
//!
//! ```
//! use libp2p_core::Transport;
//! use libp2p_tcp::TcpConfig;
//! use libp2p_noise::{Keypair, X25519, NoiseConfig};
//!
//! # fn main() {
//! let keys = Keypair::<X25519>::new();
//! let transport = TcpConfig::new().with_upgrade(NoiseConfig::xx(keys));
//! // ...
//! # }
//! ```
//!
//! [noise]: http://noiseprotocol.org/

mod error;
mod io;
mod protocol;

pub mod rt1;
pub mod rt15;

pub use error::NoiseError;
pub use io::NoiseOutput;
pub use protocol::{Keypair, PublicKey, Protocol, ProtocolParams, IX, IK, XX};
pub use protocol::x25519::X25519;

use libp2p_core::{UpgradeInfo, InboundUpgrade, OutboundUpgrade};
use tokio_io::{AsyncRead, AsyncWrite};
use zeroize::Zeroize;

/// The protocol upgrade configuration.
#[derive(Clone)]
pub struct NoiseConfig<P, C: Zeroize, R = ()> {
    keys: Keypair<C>,
    params: ProtocolParams,
    remote: R,
    _marker: std::marker::PhantomData<P>
}

impl<C: Protocol<C> + Zeroize> NoiseConfig<IX, C> {
    /// Create a new `NoiseConfig` for the IX handshake pattern.
    pub fn ix(keys: Keypair<C>) -> Self {
        NoiseConfig {
            keys,
            params: C::params_ix(),
            remote: (),
            _marker: std::marker::PhantomData
        }
    }
}

impl<C: Protocol<C> + Zeroize> NoiseConfig<XX, C> {
    /// Create a new `NoiseConfig` for the XX handshake pattern.
    pub fn xx(keys: Keypair<C>) -> Self {
        NoiseConfig {
            keys,
            params: C::params_xx(),
            remote: (),
            _marker: std::marker::PhantomData
        }
    }
}

impl<C: Protocol<C> + Zeroize> NoiseConfig<IK, C> {
    /// Create a new `NoiseConfig` for the IK handshake pattern (recipient side).
    pub fn ik_listener(keys: Keypair<C>) -> Self {
        NoiseConfig {
            keys,
            params: C::params_ik(),
            remote: (),
            _marker: std::marker::PhantomData
        }
    }
}

impl<C: Protocol<C> + Zeroize> NoiseConfig<IK, C, PublicKey<C>> {
    /// Create a new `NoiseConfig` for the IK handshake pattern (initiator side).
    pub fn ik_dialer(keys: Keypair<C>, remote: PublicKey<C>) -> Self {
        NoiseConfig {
            keys,
            params: C::params_ik(),
            remote,
            _marker: std::marker::PhantomData
        }
    }
}

// Handshake pattern IX /////////////////////////////////////////////////////

impl<T, C> InboundUpgrade<T> for NoiseConfig<IX, C>
where
    T: AsyncRead + AsyncWrite,
    NoiseConfig<IX, C>: UpgradeInfo,
    C: Protocol<C> + AsRef<[u8]> + Zeroize
{
    type Output = (PublicKey<C>, NoiseOutput<T>);
    type Error = NoiseError;
    type Future = rt1::NoiseInboundFuture<T, C>;

    fn upgrade_inbound(self, socket: T, _: Self::Info) -> Self::Future {
        let session = self.params.into_builder()
            .local_private_key(self.keys.secret().as_ref())
            .build_responder()
            .map_err(NoiseError::from);
        rt1::NoiseInboundFuture::new(socket, session)
    }
}

impl<T, C> OutboundUpgrade<T> for NoiseConfig<IX, C>
where
    T: AsyncRead + AsyncWrite,
    NoiseConfig<IX, C>: UpgradeInfo,
    C: Protocol<C> + AsRef<[u8]> + Zeroize
{
    type Output = (PublicKey<C>, NoiseOutput<T>);
    type Error = NoiseError;
    type Future = rt1::NoiseOutboundFuture<T, C>;

    fn upgrade_outbound(self, socket: T, _: Self::Info) -> Self::Future {
        let session = self.params.into_builder()
            .local_private_key(self.keys.secret().as_ref())
            .build_initiator()
            .map_err(NoiseError::from);
        rt1::NoiseOutboundFuture::new(socket, session)
    }
}

// Handshake pattern XX /////////////////////////////////////////////////////

impl<T, C> InboundUpgrade<T> for NoiseConfig<XX, C>
where
    T: AsyncRead + AsyncWrite,
    NoiseConfig<XX, C>: UpgradeInfo,
    C: Protocol<C> + AsRef<[u8]> + Zeroize
{
    type Output = (PublicKey<C>, NoiseOutput<T>);
    type Error = NoiseError;
    type Future = rt15::NoiseInboundFuture<T, C>;

    fn upgrade_inbound(self, socket: T, _: Self::Info) -> Self::Future {
        let session = self.params.into_builder()
            .local_private_key(self.keys.secret().as_ref())
            .build_responder()
            .map_err(NoiseError::from);
        rt15::NoiseInboundFuture::new(socket, session)
    }
}

impl<T, C> OutboundUpgrade<T> for NoiseConfig<XX, C>
where
    T: AsyncRead + AsyncWrite,
    NoiseConfig<XX, C>: UpgradeInfo,
    C: Protocol<C> + AsRef<[u8]> + Zeroize
{
    type Output = (PublicKey<C>, NoiseOutput<T>);
    type Error = NoiseError;
    type Future = rt15::NoiseOutboundFuture<T, C>;

    fn upgrade_outbound(self, socket: T, _: Self::Info) -> Self::Future {
        let session = self.params.into_builder()
            .local_private_key(self.keys.secret().as_ref())
            .build_initiator()
            .map_err(NoiseError::from);
        rt15::NoiseOutboundFuture::new(socket, session)
    }
}

// Handshake pattern IK /////////////////////////////////////////////////////

impl<T, C> InboundUpgrade<T> for NoiseConfig<IK, C>
where
    T: AsyncRead + AsyncWrite,
    NoiseConfig<IK, C>: UpgradeInfo,
    C: Protocol<C> + AsRef<[u8]> + Zeroize
{
    type Output = (PublicKey<C>, NoiseOutput<T>);
    type Error = NoiseError;
    type Future = rt1::NoiseInboundFuture<T, C>;

    fn upgrade_inbound(self, socket: T, _: Self::Info) -> Self::Future {
        let session = self.params.into_builder()
            .local_private_key(self.keys.secret().as_ref())
            .build_responder()
            .map_err(NoiseError::from);
        rt1::NoiseInboundFuture::new(socket, session)
    }
}

impl<T, C> OutboundUpgrade<T> for NoiseConfig<IK, C, PublicKey<C>>
where
    T: AsyncRead + AsyncWrite,
    NoiseConfig<IK, C, PublicKey<C>>: UpgradeInfo,
    C: Protocol<C> + AsRef<[u8]> + Zeroize
{
    type Output = (PublicKey<C>, NoiseOutput<T>);
    type Error = NoiseError;
    type Future = rt1::NoiseOutboundFuture<T, C>;

    fn upgrade_outbound(self, socket: T, _: Self::Info) -> Self::Future {
        let session = self.params.into_builder()
            .local_private_key(self.keys.secret().as_ref())
            .remote_public_key(self.remote.as_ref())
            .build_initiator()
            .map_err(NoiseError::from);
        rt1::NoiseOutboundFuture::new(socket, session)
    }
}