mod attributes;
mod capability;
mod command;
mod flags;
mod flow;
mod imf_view;
mod index;
mod mail_view;
mod mailbox_view;
mod mime_view;
mod request;
mod response;
mod search;
mod session;
use std::net::SocketAddr;
use anyhow::{Result, bail};
use futures::stream::{FuturesUnordered, StreamExt};
use tokio::net::TcpListener;
use tokio::sync::watch;
use tokio::sync::mpsc;
use imap_codec::imap_types::{core::Text, response::Greeting};
use imap_flow::server::{ServerFlow, ServerFlowEvent, ServerFlowOptions};
use imap_flow::stream::AnyStream;
use imap_codec::imap_types::response::{Code, Response, CommandContinuationRequest, Status};
use crate::imap::response::{Body, ResponseOrIdle};
use crate::imap::session::Instance;
use crate::imap::request::Request;
use crate::config::ImapConfig;
use crate::imap::capability::ServerCapability;
use crate::login::ArcLoginProvider;
/// Server is a thin wrapper to register our Services in BàL
pub struct Server {
bind_addr: SocketAddr,
login_provider: ArcLoginProvider,
capabilities: ServerCapability,
}
#[derive(Clone)]
struct ClientContext {
addr: SocketAddr,
login_provider: ArcLoginProvider,
must_exit: watch::Receiver<bool>,
server_capabilities: ServerCapability,
}
pub fn new(config: ImapConfig, login: ArcLoginProvider) -> Server {
Server {
bind_addr: config.bind_addr,
login_provider: login,
capabilities: ServerCapability::default(),
}
}
impl Server {
pub async fn run(self: Self, mut must_exit: watch::Receiver<bool>) -> Result<()> {
let tcp = TcpListener::bind(self.bind_addr).await?;
tracing::info!("IMAP server listening on {:#}", self.bind_addr);
let mut connections = FuturesUnordered::new();
while !*must_exit.borrow() {
let wait_conn_finished = async {
if connections.is_empty() {
futures::future::pending().await
} else {
connections.next().await
}
};
let (socket, remote_addr) = tokio::select! {
a = tcp.accept() => a?,
_ = wait_conn_finished => continue,
_ = must_exit.changed() => continue,
};
tracing::info!("IMAP: accepted connection from {}", remote_addr);
let client = ClientContext {
addr: remote_addr.clone(),
login_provider: self.login_provider.clone(),
must_exit: must_exit.clone(),
server_capabilities: self.capabilities.clone(),
};
let conn = tokio::spawn(NetLoop::handler(client, AnyStream::new(socket)));
connections.push(conn);
}
drop(tcp);
tracing::info!("IMAP server shutting down, draining remaining connections...");
while connections.next().await.is_some() {}
Ok(())
}
}
use tokio::sync::mpsc::*;
enum LoopMode {
Quit,
Interactive,
IdleUntil(tokio::sync::Notify),
}
struct NetLoop {
ctx: ClientContext,
server: ServerFlow,
cmd_tx: Sender<Request>,
resp_rx: UnboundedReceiver<ResponseOrIdle>,
}
impl NetLoop {
async fn handler(ctx: ClientContext, sock: AnyStream) {
let addr = ctx.addr.clone();
let nl = match Self::new(ctx, sock).await {
Ok(nl) => {
tracing::debug!(addr=?addr, "netloop successfully initialized");
nl
},
Err(e) => {
tracing::error!(addr=?addr, err=?e, "netloop can not be initialized, closing session");
return
}
};
match nl.core().await {
Ok(()) => {
tracing::debug!("closing successful netloop core for {:?}", addr);
}
Err(e) => {
tracing::error!("closing errored netloop core for {:?}: {}", addr, e);
}
}
}
async fn new(mut ctx: ClientContext, sock: AnyStream) -> Result<Self> {
// Send greeting
let (mut server, _) = ServerFlow::send_greeting(
sock,
ServerFlowOptions {
crlf_relaxed: false,
literal_accept_text: Text::unvalidated("OK"),
literal_reject_text: Text::unvalidated("Literal rejected"),
..ServerFlowOptions::default()
},
Greeting::ok(
Some(Code::Capability(ctx.server_capabilities.to_vec())),
"Aerogramme",
)
.unwrap(),
)
.await?;
// Start a mailbox session in background
let (cmd_tx, mut cmd_rx) = mpsc::channel::<Request>(3);
let (resp_tx, mut resp_rx) = mpsc::unbounded_channel::<ResponseOrIdle>();
tokio::spawn(Self::session(ctx.clone(), cmd_rx, resp_tx));
// Return the object
Ok(NetLoop { ctx, server, cmd_tx, resp_rx })
}
/// Coms with the background session
async fn session(ctx: ClientContext, mut cmd_rx: Receiver<Request>, resp_tx: UnboundedSender<ResponseOrIdle>) -> () {
let mut session = Instance::new(ctx.login_provider, ctx.server_capabilities);
loop {
let cmd = match cmd_rx.recv().await {
None => break,
Some(cmd_recv) => cmd_recv,
};
tracing::debug!(cmd=?cmd, sock=%ctx.addr, "command");
let maybe_response = session.request(cmd).await;
tracing::debug!(cmd=?maybe_response, sock=%ctx.addr, "response");
match resp_tx.send(maybe_response) {
Err(_) => break,
Ok(_) => (),
};
}
tracing::info!("runner is quitting");
}
async fn core(mut self) -> Result<()> {
let mut mode = LoopMode::Interactive;
loop {
mode = match mode {
LoopMode::Interactive => self.interactive_mode().await?,
LoopMode::IdleUntil(notif) => self.idle_mode(notif).await?,
LoopMode::Quit => break,
}
}
Ok(())
}
async fn interactive_mode(&mut self) -> Result<LoopMode> {
tokio::select! {
// Managing imap_flow stuff
srv_evt = self.server.progress() => match srv_evt? {
ServerFlowEvent::ResponseSent { handle: _handle, response } => {
match response {
Response::Status(Status::Bye(_)) => return Ok(LoopMode::Quit),
_ => tracing::trace!("sent to {} content {:?}", self.ctx.addr, response),
}
},
ServerFlowEvent::CommandReceived { command } => {
match self.cmd_tx.try_send(Request::ImapCommand(command)) {
Ok(_) => (),
Err(mpsc::error::TrySendError::Full(_)) => {
self.server.enqueue_status(Status::bye(None, "Too fast").unwrap());
tracing::error!("client {:?} is sending commands too fast, closing.", self.ctx.addr);
}
_ => {
self.server.enqueue_status(Status::bye(None, "Internal session exited").unwrap());
tracing::error!("session task exited for {:?}, quitting", self.ctx.addr);
}
}
},
flow => {
self.server.enqueue_status(Status::bye(None, "Unsupported server flow event").unwrap());
tracing::error!("session task exited for {:?} due to unsupported flow {:?}", self.ctx.addr, flow);
}
},
// Managing response generated by Aerogramme
maybe_msg = self.resp_rx.recv() => match maybe_msg {
Some(ResponseOrIdle::Response(response)) => {
for body_elem in response.body.into_iter() {
let _handle = match body_elem {
Body::Data(d) => self.server.enqueue_data(d),
Body::Status(s) => self.server.enqueue_status(s),
};
}
self.server.enqueue_status(response.completion);
},
Some(ResponseOrIdle::Idle) => {
let cr = CommandContinuationRequest::basic(None, "idling")?;
self.server.enqueue_continuation(cr);
return Ok(LoopMode::IdleUntil(tokio::sync::Notify::new()))
},
None => {
self.server.enqueue_status(Status::bye(None, "Internal session exited").unwrap());
tracing::error!("session task exited for {:?}, quitting", self.ctx.addr);
},
},
// When receiving a CTRL+C
_ = self.ctx.must_exit.changed() => {
self.server.enqueue_status(Status::bye(None, "Server is being shutdown").unwrap());
},
};
Ok(LoopMode::Interactive)
}
async fn idle_mode(&mut self, notif: tokio::sync::Notify) -> Result<LoopMode> {
Ok(LoopMode::IdleUntil(notif))
}
}