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use std::convert::{TryFrom, TryInto};
use std::io::{Read, Write};
use std::net::{TcpListener, TcpStream, ToSocketAddrs};
use crate::message_handler::MessageHandler;
use crate::milter_error::MilterError;
use crate::milter_message::{MilterMessage, MilterProtocol, ResponseMessage};
/// This is the main struct that opens the milter connection.
///
/// Also holds the `MessageHandler`.
pub struct Milter<'a> {
message_handler: &'a mut dyn MessageHandler,
protocol: Option<MilterProtocol>,
}
impl<'a> Milter<'a> {
fn handle_message(&mut self, s: &mut TcpStream, buffer: &[u8]) -> Result<bool, MilterError> {
let mut keep_open = true;
// print!("Raw bytes: ");
// for b in buffer.iter() {
// print!("{} ", b);
// }
// println!();
match MilterMessage::try_from(buffer) {
Ok(message) => {
// println!("Code: {}, Data: {:?}", char::from(buffer[0]), message);
match message {
MilterMessage::AbortFilterChecks => self.message_handler.abort_filter_checks(),
MilterMessage::BodyChunk { value } => {
let action = self.message_handler.body_chunk(&value);
self.send_response(s, action)?;
}
MilterMessage::ConnectionInformation {
hostname,
family,
port,
address,
} => {
let action = self
.message_handler
.connection(&hostname, &family, &port, &address);
self.send_response(s, action)?;
}
MilterMessage::DefineMacros { cmdcode, macros } => {
self.message_handler.define_macros(&cmdcode, macros);
}
MilterMessage::EndOfBody => {
let action = self.message_handler.end_of_body();
self.send_response(s, action)?;
}
MilterMessage::EndOfHeader => {
let action = self.message_handler.end_of_header();
self.send_response(s, action)?;
}
MilterMessage::Header { name, value } => {
let action = self.message_handler.header(&name, &value);
self.send_response(s, action)?;
}
MilterMessage::Helo { msg } => {
let action = self.message_handler.helo(&msg);
self.send_response(s, action)?;
}
MilterMessage::MailFrom { sender, args } => {
let action = self.message_handler.mail_from(&sender, &args);
self.send_response(s, action)?;
}
MilterMessage::OptionNegotiation {
version,
actions,
protocol: _,
} => {
// TODO: Create OptionNegotiation by checking for configured handlers (or
// let the user specify)
let response_msg = ResponseMessage::option_negotiation(
version,
actions,
self.protocol.as_ref().unwrap_or(&MilterProtocol::default()),
);
self.send_response(s, response_msg)?;
}
MilterMessage::QuitCommunication => {
keep_open = false;
}
MilterMessage::RecipientInformation { recipient, args } => {
let action = self.message_handler.recipient(&recipient, &args);
self.send_response(s, action)?;
}
};
}
Err(_e) => {
// println!("Error parsing message: {}", e);
// print!("raw bytes: ");
// for b in buffer.iter() {
// print!("{} ", b);
// }
// println!();
let mut response = Vec::with_capacity(5);
response.append(&mut u32::to_be_bytes(1).to_vec());
response.push(b'c');
// println!("Response length: {}", response.len());
// for b in response.iter() {
// print!("{} ", b);
// }
// println!();
s.write_all(&response)?;
}
}
Ok(keep_open)
}
pub(crate) fn new(
message_handler: &'a mut dyn MessageHandler,
protocol: Option<MilterProtocol>,
) -> Self {
Self {
message_handler,
protocol,
}
}
/// Opens the connection to the MTA service.
///
/// - `address` defines the socket address of the MTA.
pub fn run<S: ToSocketAddrs>(&'a mut self, address: S) -> Result<(), MilterError> {
let listener = TcpListener::bind(address)?;
for stream in listener.incoming() {
match stream {
Ok(mut s) => {
let mut keep_open = true;
while keep_open {
let mut buffer = [0; std::mem::size_of::<u32>()];
let mut len = s.peek(&mut buffer)?;
// Only start reading when at least the message size (4 bytes) is available
if len >= std::mem::size_of::<u32>() {
len = s.read(&mut buffer)?;
if len > 0 {
let msg_len = u32::from_be_bytes(buffer);
// println!("Message length: {}", msg_len);
let mut buffer = vec![0; msg_len.try_into()?];
s.read_exact(&mut buffer)?;
keep_open = self.handle_message(&mut s, &buffer)?;
}
}
}
}
Err(e) => eprintln!("Error: {}", e),
}
}
Ok(())
}
fn send_response<R: Into<ResponseMessage>>(
&self,
s: &mut TcpStream,
response_msg: R,
) -> Result<(), MilterError> {
let response_msg = response_msg.into();
// println!("Sending response: {:?}", response_msg);
let response = response_msg.get_content();
// println!("Response length: {}", response.len());
// for b in response.iter() {
// print!("{} ", b);
// }
// println!();
s.write_all(&response)?;
s.flush()?;
Ok(())
}
}