diff options
Diffstat (limited to 'src/imap/session.rs')
| -rw-r--r-- | src/imap/session.rs | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/imap/session.rs b/src/imap/session.rs new file mode 100644 index 0000000..2035634 --- /dev/null +++ b/src/imap/session.rs @@ -0,0 +1,201 @@ +use std::sync::Arc; + +use anyhow::Error; +use boitalettres::errors::Error as BalError; +use boitalettres::proto::{Request, Response}; +use futures::future::BoxFuture; +use futures::future::FutureExt; +use imap_codec::types::command::CommandBody; +use imap_codec::types::response::{Capability, Code, Data, Response as ImapRes, Status}; +use tokio::sync::mpsc::error::TrySendError; +use tokio::sync::{mpsc, oneshot}; + +use crate::command::{anonymous,authenticated,selected}; +use crate::login::Credentials; +use crate::mailbox::Mailbox; +use crate::LoginProvider; + +/* This constant configures backpressure in the system, + * or more specifically, how many pipelined messages are allowed + * before refusing them + */ +const MAX_PIPELINED_COMMANDS: usize = 10; + +struct Message { + req: Request, + tx: oneshot::Sender<Result<Response, BalError>>, +} + +//----- + +pub struct Manager { + tx: mpsc::Sender<Message>, +} + +impl Manager { + pub fn new(login_provider: ArcLoginProvider) -> Self { + let (tx, rx) = mpsc::channel(MAX_PIPELINED_COMMANDS); + tokio::spawn(async move { + let mut instance = Instance::new(login_provider, rx); + instance.start().await; + }); + Self { tx } + } + + pub fn process(&self, req: Request) -> BoxFuture<'static, Result<Response, BalError>> { + let (tx, rx) = oneshot::channel(); + let tag = req.tag.clone(); + let msg = Message { req, tx }; + + // We use try_send on a bounded channel to protect the daemons from DoS. + // Pipelining requests in IMAP are a special case: they should not occure often + // and in a limited number (like 3 requests). Someone filling the channel + // will probably be malicious so we "rate limit" them. + match self.tx.try_send(msg) { + Ok(()) => (), + Err(TrySendError::Full(_)) => { + return async { + Status::bad(Some(tag), None, "Too fast! Send less pipelined requests!") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(|e| BalError::Text(e.to_string())) + } + .boxed() + } + Err(TrySendError::Closed(_)) => { + return async { + Status::bad(Some(tag), None, "The session task has exited") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(|e| BalError::Text(e.to_string())) + } + .boxed() + } + }; + + // @FIXME add a timeout, handle a session that fails. + async { + match rx.await { + Ok(r) => r, + Err(e) => { + tracing::warn!("Got error {:#?}", e); + Status::bad(Some(tag), None, "No response from the session handler") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(|e| BalError::Text(e.to_string())) + } + } + } + .boxed() + } +} + +//----- + +pub struct Context<'a> { + req: &'a Request, + state: &'a mut flow::State, + login: ArcLoginProvider, +} + +pub struct Instance { + rx: mpsc::Receiver<Message>, + + pub login_provider: ArcLoginProvider, + pub state: flow::State, +} +impl Instance { + fn new( + login_provider: ArcLoginProvider, + rx: mpsc::Receiver<Message>, + ) -> Self { + Self { + login_provider, + rx, + state: flow::State::NotAuthenticated, + } + } + + //@FIXME add a function that compute the runner's name from its local info + // to ease debug + // fn name(&self) -> String { } + + async fn start(&mut self) { + //@FIXME add more info about the runner + tracing::debug!("starting runner"); + + while let Some(msg) = self.rx.recv().await { + let ctx = Context { req: &msg.req, state: &mut self.state, login: self.login_provider }; + + // Command behavior is modulated by the state. + // To prevent state error, we handle the same command in separate code path depending + // on the State. + let cmd_res = match self.state { + flow::State::NotAuthenticated => anonymous::dispatch(ctx).await, + flow::State::Authenticated(user) => authenticated::dispatch(ctx).await, + flow::State::Selected(user, mailbox) => selected::dispatch(ctx).await, + flow::State::Logout => Status::bad(Some(ctx.req.tag.clone()), None, "No commands are allowed in the LOGOUT state.") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(Error::msg), + }; + +/* + + match req.body { + CommandBody::Capability => anonymous::capability().await, + CommandBody::Login { username, password } => anonymous::login(self.login_provider, username, password).await.and_then(|(user, response)| { + self.state.authenticate(user)?; + Ok(response) + }, + _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the ANONYMOUS state.") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(Error::msg), + + }, + flow::State::Authenticated(user) => match req.body { + CommandBody::Capability => anonymous::capability().await, // we use the same implem for now + CommandBody::Lsub { reference, mailbox_wildcard, } => authenticated::lsub(reference, mailbox_wildcard).await, + CommandBody::List { reference, mailbox_wildcard, } => authenticated::list(reference, mailbox_wildcard).await, + CommandBody::Select { mailbox } => authenticated::select(user, mailbox).await.and_then(|(mailbox, response)| { + self.state.select(mailbox); + Ok(response) + }), + _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the AUTHENTICATED state.") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(Error::msg), + }, + flow::State::Selected(user, mailbox) => match req.body { + CommandBody::Capability => anonymous::capability().await, // we use the same implem for now + CommandBody::Fetch { sequence_set, attributes, uid, } => selected::fetch(sequence_set, attributes, uid).await, + _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the SELECTED state.") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(Error::msg), + }, + flow::State::Logout => Status::bad(Some(msg.req.tag.clone()), None, "No commands are allowed in the LOGOUT state.") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(Error::msg), + } + */ + + let imap_res = match cmd_res { + Ok(new_state, imap_res) => { + self.state = new_state; + Ok(imap_res) + }, + Err(e) if Ok(be) = e.downcast::<BalError>() => Err(be), + Err(e) => { + tracing::warn!(error=%e, "internal.error"); + Ok(Status::bad(Some(msg.req.tag.clone()), None, "Internal error") + .map(|s| vec![ImapRes::Status(s)]) + .map_err(|e| BalError::Text(e.to_string()))) + } + }; + + //@FIXME I think we should quit this thread on error and having our manager watch it, + // and then abort the session as it is corrupted. + msg.tx.send(imap_res).unwrap_or_else(|e| { + tracing::warn!("failed to send imap response to manager: {:#?}", e) + }); + } + + //@FIXME add more info about the runner + tracing::debug!("exiting runner"); + } +} |