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
/// TLS connection mode.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum TlsMode {
/// TLS from connection start (typically port 465).
ImplicitTls,
/// Upgrade plaintext to TLS after EHLO (typically port 587).
StartTls,
/// No encryption (for trusted local relays, typically port 25).
Plain,
}
/// TLS certificate verification mode.
#[derive(Debug, Clone, Default)]
pub enum TlsVerify {
/// Verify server certificate against system CA bundle (default).
#[default]
Verify,
/// Accept any certificate (for self-signed servers).
SkipVerify,
/// Verify against a custom CA certificate in PEM format.
CustomCa(Vec<u8>),
}
/// SMTP authentication credentials.
#[derive(Debug, Clone)]
pub struct Credentials {
pub username: String,
pub password: String,
}
/// SMTP connection configuration.
#[derive(Debug, Clone)]
pub struct SmtpConfig {
pub host: String,
pub port: u16,
pub tls_mode: TlsMode,
pub credentials: Option<Credentials>,
pub timeout_ms: u32,
pub tls_verify: TlsVerify,
}
impl SmtpConfig {
/// Create a new SMTP configuration.
///
/// Defaults: implicit TLS, no credentials, 5s timeout, verify certs.
pub fn new(host: &str, port: u16) -> Self {
Self {
host: host.to_string(),
port,
tls_mode: TlsMode::ImplicitTls,
credentials: None,
timeout_ms: 5000,
tls_verify: TlsVerify::default(),
}
}
/// Set the TLS mode.
pub fn tls_mode(mut self, mode: TlsMode) -> Self {
self.tls_mode = mode;
self
}
/// Set authentication credentials.
pub fn credentials(mut self, username: &str, password: &str) -> Self {
self.credentials = Some(Credentials {
username: username.to_string(),
password: password.to_string(),
});
self
}
/// Set per-command timeout in milliseconds.
pub fn timeout_ms(mut self, ms: u32) -> Self {
self.timeout_ms = ms;
self
}
/// Enable certificate verification (default).
pub fn verify_certs(mut self) -> Self {
self.tls_verify = TlsVerify::Verify;
self
}
/// Skip certificate verification.
pub fn skip_cert_verification(mut self) -> Self {
self.tls_verify = TlsVerify::SkipVerify;
self
}
/// Use a custom CA certificate in PEM format.
pub fn ca_cert_pem(mut self, pem: &[u8]) -> Self {
self.tls_verify = TlsVerify::CustomCa(pem.to_vec());
self
}
}