1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
use std::net::SocketAddr;
use std::{pin::Pin, sync::Arc};
use anyhow::Result;
use async_trait::async_trait;
use duplexify::Duplex;
use futures::{io, AsyncRead, AsyncReadExt, AsyncWrite};
use futures::{
stream,
stream::{FuturesOrdered, FuturesUnordered},
StreamExt,
};
use log::*;
use tokio::net::TcpListener;
use tokio::select;
use tokio::sync::watch;
use tokio_util::compat::*;
use smtp_message::{Email, EscapedDataReader, Reply, ReplyCode};
use smtp_server::{reply, Config, ConnectionMetadata, Decision, MailMetadata};
use crate::config::*;
use crate::login::*;
use crate::mail::incoming::EncryptedMessage;
pub struct LmtpServer {
bind_addr: SocketAddr,
hostname: String,
login_provider: Arc<dyn LoginProvider + Send + Sync>,
}
impl LmtpServer {
pub fn new(
config: LmtpConfig,
login_provider: Arc<dyn LoginProvider + Send + Sync>,
) -> Arc<Self> {
Arc::new(Self {
bind_addr: config.bind_addr,
hostname: config.hostname,
login_provider,
})
}
pub async fn run(self: &Arc<Self>, mut must_exit: watch::Receiver<bool>) -> Result<()> {
let tcp = TcpListener::bind(self.bind_addr).await?;
info!("LMTP 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) = select! {
a = tcp.accept() => a?,
_ = wait_conn_finished => continue,
_ = must_exit.changed() => continue,
};
info!("LMTP: accepted connection from {}", remote_addr);
let conn = tokio::spawn(smtp_server::interact(
socket.compat(),
smtp_server::IsAlreadyTls::No,
(),
self.clone(),
));
connections.push(conn);
}
drop(tcp);
info!("LMTP server shutting down, draining remaining connections...");
while connections.next().await.is_some() {}
Ok(())
}
}
// ----
pub struct Message {
to: Vec<PublicCredentials>,
}
#[async_trait]
impl Config for LmtpServer {
type Protocol = smtp_server::protocol::Lmtp;
type ConnectionUserMeta = ();
type MailUserMeta = Message;
fn hostname(&self, _conn_meta: &ConnectionMetadata<()>) -> &str {
&self.hostname
}
async fn new_mail(&self, _conn_meta: &mut ConnectionMetadata<()>) -> Message {
Message { to: vec![] }
}
async fn tls_accept<IO>(
&self,
_io: IO,
_conn_meta: &mut ConnectionMetadata<()>,
) -> io::Result<Duplex<Pin<Box<dyn Send + AsyncRead>>, Pin<Box<dyn Send + AsyncWrite>>>>
where
IO: Send + AsyncRead + AsyncWrite,
{
Err(io::Error::new(
io::ErrorKind::InvalidInput,
"TLS not implemented for LMTP server",
))
}
async fn filter_from(
&self,
from: Option<Email>,
_meta: &mut MailMetadata<Message>,
_conn_meta: &mut ConnectionMetadata<()>,
) -> Decision<Option<Email>> {
Decision::Accept {
reply: reply::okay_from().convert(),
res: from,
}
}
async fn filter_to(
&self,
to: Email,
meta: &mut MailMetadata<Message>,
_conn_meta: &mut ConnectionMetadata<()>,
) -> Decision<Email> {
let to_str = match to.hostname.as_ref() {
Some(h) => format!("{}@{}", to.localpart, h),
None => to.localpart.to_string(),
};
match self.login_provider.public_login(&to_str).await {
Ok(creds) => {
meta.user.to.push(creds);
Decision::Accept {
reply: reply::okay_to().convert(),
res: to,
}
}
Err(e) => Decision::Reject {
reply: Reply {
code: ReplyCode::POLICY_REASON,
ecode: None,
text: vec![smtp_message::MaybeUtf8::Utf8(e.to_string())],
},
},
}
}
async fn handle_mail<'resp, R>(
&'resp self,
reader: &mut EscapedDataReader<'_, R>,
meta: MailMetadata<Message>,
_conn_meta: &'resp mut ConnectionMetadata<()>,
) -> Pin<Box<dyn futures::Stream<Item = Decision<()>> + Send + 'resp>>
where
R: Send + Unpin + AsyncRead,
{
let err_response_stream = |meta: MailMetadata<Message>, msg: String| {
Box::pin(
stream::iter(meta.user.to.into_iter()).map(move |_| Decision::Reject {
reply: Reply {
code: ReplyCode::POLICY_REASON,
ecode: None,
text: vec![smtp_message::MaybeUtf8::Utf8(msg.clone())],
},
}),
)
};
let mut text = Vec::new();
if let Err(e) = reader.read_to_end(&mut text).await {
return err_response_stream(meta, format!("io error: {}", e));
}
reader.complete();
let encrypted_message = match EncryptedMessage::new(text) {
Ok(x) => Arc::new(x),
Err(e) => return err_response_stream(meta, e.to_string()),
};
Box::pin(
meta.user
.to
.into_iter()
.map(move |creds| {
let encrypted_message = encrypted_message.clone();
async move {
match encrypted_message.deliver_to(creds).await {
Ok(()) => Decision::Accept {
reply: reply::okay_mail().convert(),
res: (),
},
Err(e) => Decision::Reject {
reply: Reply {
code: ReplyCode::POLICY_REASON,
ecode: None,
text: vec![smtp_message::MaybeUtf8::Utf8(e.to_string())],
},
},
}
}
})
.collect::<FuturesOrdered<_>>(),
)
}
}
|
