diff options
Diffstat (limited to 'src/smtp.rs')
| -rw-r--r-- | src/smtp.rs | 242 |
1 files changed, 0 insertions, 242 deletions
diff --git a/src/smtp.rs b/src/smtp.rs deleted file mode 100644 index 2795ecf..0000000 --- a/src/smtp.rs +++ /dev/null @@ -1,242 +0,0 @@ -use std::{ - io::{BufRead, BufReader, Write}, - net::{IpAddr, SocketAddr, TcpListener, TcpStream}, -}; - -use anyhow::Result; -use tokio::spawn; - -const SERVER_NAME: &str = ""; - -pub struct SmtpServer { - listener: TcpListener, - running: bool, -} - -impl SmtpServer { - pub fn new(ip: [u8; 4], port: u16) -> Result<Self> { - Ok(Self { - listener: TcpListener::bind((IpAddr::from(ip), port))?, - running: false, - }) - } - - // TODO: trap SIGINT to stop server? - pub async fn run(&mut self) -> Result<()> { - self.running = true; - while self.running { - let (stream, addr) = self.listener.accept()?; - let session = SessionHandler { - addr, - state: SessionState::default(), - client_host: String::new(), - from: None, - to: Vec::new(), - data: String::new(), - }; - spawn(session.run(stream)); - } - Ok(()) - } -} - -struct SessionHandler { - addr: SocketAddr, - state: SessionState, - client_host: String, - from: Option<String>, - to: Vec<String>, - data: String, -} - -impl SessionHandler { - async fn run(mut self, stream: TcpStream) -> Result<()> { - let mut writer = stream.try_clone()?; - let mut r = BufReader::new(&stream); - let mut buffer = String::new(); - - writer.write_all( - Reply::Ready(String::from(SERVER_NAME)) - .to_string() - .as_bytes(), - )?; - - loop { - buffer.clear(); - if r.read_line(&mut buffer)? == 0 { - break; - } - log::debug!("Received '{}' from '{}'", buffer.trim(), self.addr); - - // In this state the server is not expecting commands as the input is part of the email - // message - if self.state == SessionState::AwaitingMailInput { - if buffer.starts_with(".\r\n") { - self.process_mail().await?; - continue; - } - - self.data.push_str(&buffer); - continue; - } - - let command = match Command::try_from(buffer.as_str()) { - Err(_) => { - writer.write_all(Reply::InvalidCommand.to_string().as_bytes())?; - continue; - } - Ok(v) => v, - }; - let res = self.apply(command).await?; - writer.write_all(res.to_string().as_bytes())?; - } - - log::info!("Connection closed by {}", self.addr); - Ok(()) - } - - async fn apply(&mut self, command: Command) -> Result<Reply> { - match &command { - Command::HELO(hostname) => self.helo(hostname).await, - Command::MAIL(from) => self.mail(from).await, - Command::RCPT(to) => self.rcpt(to).await, - Command::DATA => self.start_data().await, - } - } - - /// HELO resets buffers - async fn helo(&mut self, hostname: &str) -> Result<Reply> { - self.client_host = String::from(hostname); - self.state = SessionState::Normal; - self.from = None; - self.to.clear(); - Ok(Reply::Completed(String::from(SERVER_NAME))) - } - - /// TODO: Validate email address - /// MAIL resets buffers - async fn mail(&mut self, from: &str) -> Result<Reply> { - if from.is_empty() { - return Ok(Reply::InvalidParameter); - } - - self.from = Some(String::from(from)); - self.to.clear(); - self.state = SessionState::MailTransaction; - - Ok(Reply::Completed(String::from("Ok"))) - } - - /// TODO: Validate email addresses - /// Only after having started a mail transaction - async fn rcpt(&mut self, to: &str) -> Result<Reply> { - if self.state != SessionState::MailTransaction { - return Ok(Reply::BadSequence); - } - - if to.is_empty() { - return Ok(Reply::InvalidParameter); - } - - self.to.push(String::from(to)); - Ok(Reply::Completed(String::from("Ok"))) - } - - /// Only after having started a mail transaction - async fn start_data(&mut self) -> std::result::Result<Reply, anyhow::Error> { - if self.state != SessionState::MailTransaction { - return Ok(Reply::BadSequence); - } - - // Should I return a more meaningful string with this error code? - if self.from.is_none() || self.to.is_empty() { - return Ok(Reply::InvalidCommand); - } - - self.state = SessionState::AwaitingMailInput; - - Ok(Reply::StartMailInput) - } - - // TODO: Forward and store email - async fn process_mail(&mut self) -> Result<Reply> { - if self.from.is_none() || self.to.is_empty() || self.data.trim().is_empty() { - return Ok(Reply::InvalidCommand); - } - - self.state = SessionState::Normal; - self.from = None; - self.to.clear(); - self.data.clear(); - - todo!() - } -} - -#[derive(PartialEq, Default)] -enum SessionState { - #[default] - WaitingHelo, - MailTransaction, - AwaitingMailInput, - Normal, -} - -enum Reply { - Ready(String), - Completed(String), - StartMailInput, - InvalidCommand, - InvalidParameter, - BadSequence, -} - -impl std::fmt::Display for Reply { - fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { - match self { - Reply::Ready(hostname) => write!(f, "220 {}", hostname), - Reply::Completed(hostname) => write!(f, "250 {}", hostname), - Reply::InvalidCommand => write!(f, "500 Invalid command"), - Reply::InvalidParameter => write!(f, "501 Parameter error"), - Reply::BadSequence => write!(f, "503 Bad sequence of commands"), - Reply::StartMailInput => write!(f, "354 <CRLF>.<CRLF>"), - } - } -} - -enum Command { - HELO(String), - MAIL(String), - RCPT(String), - DATA, -} - -impl TryFrom<&str> for Command { - type Error = anyhow::Error; - - fn try_from(value: &str) -> std::result::Result<Self, Self::Error> { - if value.len() >= 5 && value.to_lowercase().starts_with("helo ") { - return Ok(Command::HELO(String::from(&value[5..]))); - } - - if value.len() >= 11 - && value.to_lowercase().starts_with("mail from:<") - && value.contains('>') - { - let from = &value[11..value.find('>').unwrap()]; - return Ok(Command::MAIL(String::from(from))); - } - - if value.len() >= 9 && value.to_lowercase().starts_with("rcpt to:<") && value.contains('>') - { - let to = &value[9..value.find('>').unwrap()]; - return Ok(Command::RCPT(String::from(to))); - } - - if value.to_lowercase().starts_with("data") { - return Ok(Command::DATA); - } - - Err(anyhow::format_err!("Invalid command")) - } -} |