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//! TCP transport configuration.

use crate::{
    crypto::noise::{MAX_READ_AHEAD_FACTOR, MAX_WRITE_BUFFER_SIZE},
    transport::{CONNECTION_OPEN_TIMEOUT, SUBSTREAM_OPEN_TIMEOUT},
};

/// TCP transport configuration.
#[derive(Debug, Clone)]
pub struct Config {
    /// Listen address for the transport.
    ///
    /// Default listen addresses are ["/ip4/0.0.0.0/tcp/0", "/ip6/::/tcp/0"].
    pub listen_addresses: Vec<multiaddr::Multiaddr>,

    /// Whether to set `SO_REUSEPORT` and bind a socket to the listen address port for outbound
    /// connections.
    ///
    /// Note that `SO_REUSEADDR` is always set on listening sockets.
    ///
    /// Defaults to `true`.
    pub reuse_port: bool,

    /// Enable `TCP_NODELAY`.
    ///
    /// Defaults to `false`.
    pub nodelay: bool,

    /// Yamux configuration.
    pub yamux_config: crate::yamux::Config,

    /// Noise read-ahead frame count.
    ///
    /// Specifies how many Noise frames are read per call to the underlying socket.
    ///
    /// By default this is configured to `5` so each call to the underlying socket can read up
    /// to `5` Noise frame per call. Fewer frames may be read if there isn't enough data in the
    /// socket. Each Noise frame is `65 KB` so the default setting allocates `65 KB * 5 = 325 KB`
    /// per connection.
    pub noise_read_ahead_frame_count: usize,

    /// Noise write buffer size.
    ///
    /// Specifes how many Noise frames are tried to be coalesced into a single system call.
    /// By default the value is set to `2` which means that the `NoiseSocket` will allocate
    /// `130 KB` for each outgoing connection.
    ///
    /// The write buffer size is separate from the read-ahead frame count so by default
    /// the Noise code will allocate `2 * 65 KB + 5 * 65 KB = 455 KB` per connection.
    pub noise_write_buffer_size: usize,

    /// Connection open timeout.
    ///
    /// How long should litep2p wait for a connection to be opened before the host
    /// is deemed unreachable.
    pub connection_open_timeout: std::time::Duration,

    /// Substream open timeout.
    ///
    /// How long should litep2p wait for a substream to be opened before considering
    /// the substream rejected.
    pub substream_open_timeout: std::time::Duration,
}

impl Default for Config {
    fn default() -> Self {
        Self {
            listen_addresses: vec![
                "/ip4/0.0.0.0/tcp/0".parse().expect("valid address"),
                "/ip6/::/tcp/0".parse().expect("valid address"),
            ],
            reuse_port: true,
            nodelay: false,
            yamux_config: Default::default(),
            noise_read_ahead_frame_count: MAX_READ_AHEAD_FACTOR,
            noise_write_buffer_size: MAX_WRITE_BUFFER_SIZE,
            connection_open_timeout: CONNECTION_OPEN_TIMEOUT,
            substream_open_timeout: SUBSTREAM_OPEN_TIMEOUT,
        }
    }
}
