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//! Variable server parameters lists
use crate::provider::{Protocol, Socket};
/// Set of variable parameters to try during configuration.
///
/// Can be loaded from offline provider database, online configuration
/// or derived from user entered parameters.
#[derive(Debug, Clone, PartialEq)]
pub(crate) struct ServerParams {
/// Protocol, such as IMAP or SMTP.
pub protocol: Protocol,
/// Server hostname, empty if unknown.
pub hostname: String,
/// Server port, zero if unknown.
pub port: u16,
/// Socket security, such as TLS or STARTTLS, Socket::Automatic if unknown.
pub socket: Socket,
/// Username, empty if unknown.
pub username: String,
/// Whether TLS certificates should be strictly checked or not, `None` for automatic.
pub strict_tls: Option<bool>,
}
impl ServerParams {
fn expand_usernames(self, addr: &str) -> Vec<ServerParams> {
let mut res = Vec::new();
if self.username.is_empty() {
res.push(Self {
username: addr.to_string(),
..self.clone()
});
if let Some(at) = addr.find('@') {
res.push(Self {
username: addr.split_at(at).0.to_string(),
..self
});
}
} else {
res.push(self)
}
res
}
fn expand_hostnames(self, param_domain: &str) -> Vec<ServerParams> {
if self.hostname.is_empty() {
vec![
// Try "imap.ex.org"/"smtp.ex.org" and "mail.ex.org" first because if a server exists
// under this address, it's likely the correct one.
Self {
hostname: match self.protocol {
Protocol::Imap => "imap.".to_string() + param_domain,
Protocol::Smtp => "smtp.".to_string() + param_domain,
},
..self.clone()
},
Self {
hostname: "mail.".to_string() + param_domain,
..self.clone()
},
// Try "ex.org" last because if it's wrong and the server is configured to
// not answer at all, configuration may be stuck for several minutes.
Self {
hostname: param_domain.to_string(),
..self
},
]
} else {
vec![self]
}
}
fn expand_ports(mut self) -> Vec<ServerParams> {
// Try to infer port from socket security.
if self.port == 0 {
self.port = match self.socket {
Socket::Ssl => match self.protocol {
Protocol::Imap => 993,
Protocol::Smtp => 465,
},
Socket::Starttls | Socket::Plain => match self.protocol {
Protocol::Imap => 143,
Protocol::Smtp => 587,
},
Socket::Automatic => 0,
}
}
if self.port == 0 {
// Neither port nor security is set.
//
// Try common secure combinations.
vec![
// Try TLS
Self {
socket: Socket::Ssl,
port: match self.protocol {
Protocol::Imap => 993,
Protocol::Smtp => 465,
},
..self.clone()
},
// Try STARTTLS
Self {
socket: Socket::Starttls,
port: match self.protocol {
Protocol::Imap => 143,
Protocol::Smtp => 587,
},
..self
},
]
} else if self.socket == Socket::Automatic {
vec![
// Try TLS over user-provided port.
Self {
socket: Socket::Ssl,
..self.clone()
},
// Try STARTTLS over user-provided port.
Self {
socket: Socket::Starttls,
..self
},
]
} else {
vec![self]
}
}
fn expand_strict_tls(self) -> Vec<ServerParams> {
vec![Self {
// Strict if not set by the user or provider database.
strict_tls: Some(self.strict_tls.unwrap_or(true)),
..self
}]
}
}
/// Expands vector of `ServerParams`, replacing placeholders with
/// variants to try.
pub(crate) fn expand_param_vector(
v: Vec<ServerParams>,
addr: &str,
domain: &str,
) -> Vec<ServerParams> {
v.into_iter()
// The order of expansion is important.
//
// Ports are expanded the last, so they are changed the first. Username is only changed if
// default value (address with domain) didn't work for all available hosts and ports.
.flat_map(|params| params.expand_strict_tls().into_iter())
.flat_map(|params| params.expand_usernames(addr).into_iter())
.flat_map(|params| params.expand_hostnames(domain).into_iter())
.flat_map(|params| params.expand_ports().into_iter())
.collect()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_expand_param_vector() {
let v = expand_param_vector(
vec![ServerParams {
protocol: Protocol::Imap,
hostname: "example.net".to_string(),
port: 0,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true),
}],
"foobar@example.net",
"example.net",
);
assert_eq!(
v,
vec![ServerParams {
protocol: Protocol::Imap,
hostname: "example.net".to_string(),
port: 993,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true)
}],
);
let v = expand_param_vector(
vec![ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 123,
socket: Socket::Automatic,
username: "foobar".to_string(),
strict_tls: None,
}],
"foobar@example.net",
"example.net",
);
assert_eq!(
v,
vec![
ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 123,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true),
},
ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 123,
socket: Socket::Starttls,
username: "foobar".to_string(),
strict_tls: Some(true)
},
],
);
// Test that strict_tls is not expanded for plaintext connections.
let v = expand_param_vector(
vec![ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 123,
socket: Socket::Plain,
username: "foobar".to_string(),
strict_tls: Some(true),
}],
"foobar@example.net",
"example.net",
);
assert_eq!(
v,
vec![ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 123,
socket: Socket::Plain,
username: "foobar".to_string(),
strict_tls: Some(true)
}],
);
// Test that "example.net" is tried after "*.example.net".
let v = expand_param_vector(
vec![ServerParams {
protocol: Protocol::Imap,
hostname: "".to_string(),
port: 10480,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true),
}],
"foobar@example.net",
"example.net",
);
assert_eq!(
v,
vec![
ServerParams {
protocol: Protocol::Imap,
hostname: "imap.example.net".to_string(),
port: 10480,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true)
},
ServerParams {
protocol: Protocol::Imap,
hostname: "mail.example.net".to_string(),
port: 10480,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true)
},
ServerParams {
protocol: Protocol::Imap,
hostname: "example.net".to_string(),
port: 10480,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true)
}
],
);
// Test that TLS is preferred to STARTTLS
// when the port and security are not set.
let v = expand_param_vector(
vec![ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 0,
socket: Socket::Automatic,
username: "foobar".to_string(),
strict_tls: Some(true),
}],
"foobar@example.net",
"example.net",
);
assert_eq!(
v,
vec![
ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 465,
socket: Socket::Ssl,
username: "foobar".to_string(),
strict_tls: Some(true)
},
ServerParams {
protocol: Protocol::Smtp,
hostname: "example.net".to_string(),
port: 587,
socket: Socket::Starttls,
username: "foobar".to_string(),
strict_tls: Some(true)
},
],
);
}
}