Files
chatmail-core/src/smtp.rs
Simon Laux 6b0b551973 cargo fmt
2024-10-23 14:07:55 +02:00

671 lines
23 KiB
Rust

//! # SMTP transport module.
mod connect;
pub mod send;
use anyhow::{bail, format_err, Context as _, Error, Result};
use async_smtp::response::{Category, Code, Detail};
use async_smtp::{EmailAddress, SmtpTransport};
use crate::chat::{add_info_msg_with_cmd, ChatId};
use crate::config::Config;
use crate::contact::{Contact, ContactId};
use crate::context::Context;
use crate::events::EventType;
use crate::login_param::prioritize_server_login_params;
use crate::login_param::{ConfiguredLoginParam, ConfiguredServerLoginParam};
use crate::message::Message;
use crate::message::{self, MsgId};
use crate::mimefactory::MimeFactory;
use crate::net::proxy::ProxyConfig;
use crate::net::session::SessionBufStream;
use crate::scheduler::connectivity::ConnectivityStore;
use crate::stock_str::unencrypted_email;
use crate::tools::{self, time_elapsed};
use crate::{spawn_named_task, sql};
#[derive(Default)]
pub(crate) struct Smtp {
/// SMTP connection.
transport: Option<SmtpTransport<Box<dyn SessionBufStream>>>,
/// Email address we are sending from.
from: Option<EmailAddress>,
/// Timestamp of last successful send/receive network interaction
/// (eg connect or send succeeded). On initialization and disconnect
/// it is set to None.
last_success: Option<tools::Time>,
pub(crate) connectivity: ConnectivityStore,
/// If sending the last message failed, contains the error message.
pub(crate) last_send_error: Option<String>,
}
impl Smtp {
/// Create a new Smtp instances.
pub fn new() -> Self {
Default::default()
}
/// Disconnect the SMTP transport and drop it entirely.
pub fn disconnect(&mut self) {
if let Some(mut transport) = self.transport.take() {
// Closing connection with a QUIT command may take some time, especially if it's a
// stale connection and an attempt to send the command times out. Send a command in a
// separate task to avoid waiting for reply or timeout.
spawn_named_task!("disconnect SMTP", async move { transport.quit().await });
}
self.last_success = None;
}
/// Return true if smtp was connected but is not known to
/// have been successfully used the last 60 seconds
pub fn has_maybe_stale_connection(&self) -> bool {
if let Some(last_success) = self.last_success {
time_elapsed(&last_success).as_secs() > 60
} else {
false
}
}
/// Check whether we are connected.
pub fn is_connected(&self) -> bool {
self.transport.is_some()
}
/// Connect using configured parameters.
pub async fn connect_configured(&mut self, context: &Context) -> Result<()> {
if self.has_maybe_stale_connection() {
info!(context, "Closing stale connection.");
self.disconnect();
}
if self.is_connected() {
return Ok(());
}
self.connectivity.set_connecting(context).await;
let lp = ConfiguredLoginParam::load(context)
.await?
.context("Not configured")?;
self.connect(
context,
&lp.smtp,
&lp.smtp_password,
&lp.proxy_config,
&lp.addr,
lp.strict_tls(),
lp.oauth2,
)
.await
}
/// Connect using the provided login params.
#[allow(clippy::too_many_arguments)]
pub async fn connect(
&mut self,
context: &Context,
login_params: &[ConfiguredServerLoginParam],
password: &str,
proxy_config: &Option<ProxyConfig>,
addr: &str,
strict_tls: bool,
oauth2: bool,
) -> Result<()> {
if self.is_connected() {
warn!(context, "SMTP already connected.");
return Ok(());
}
let from = EmailAddress::new(addr.to_string())
.with_context(|| format!("Invalid address {addr:?}"))?;
self.from = Some(from);
let login_params =
prioritize_server_login_params(&context.sql, login_params, "smtp").await?;
for lp in login_params {
info!(context, "SMTP trying to connect to {}.", &lp.connection);
let transport = match connect::connect_and_auth(
context,
proxy_config,
strict_tls,
lp.connection.clone(),
oauth2,
addr,
&lp.user,
password,
)
.await
{
Ok(transport) => transport,
Err(err) => {
warn!(context, "SMTP failed to connect and authenticate: {err:#}.");
continue;
}
};
self.transport = Some(transport);
self.last_success = Some(tools::Time::now());
context.emit_event(EventType::SmtpConnected(format!(
"SMTP-LOGIN as {} ok",
lp.user,
)));
return Ok(());
}
Err(format_err!("SMTP failed to connect"))
}
}
pub(crate) enum SendResult {
/// Message was sent successfully.
Success,
/// Permanent error, message sending has failed.
Failure(Error),
/// Temporary error, the message should be retried later.
Retry,
}
/// Tries to send a message.
pub(crate) async fn smtp_send(
context: &Context,
recipients: &[async_smtp::EmailAddress],
message: &str,
smtp: &mut Smtp,
msg_id: Option<MsgId>,
) -> SendResult {
if std::env::var(crate::DCC_MIME_DEBUG).is_ok() {
info!(context, "SMTP-sending out mime message:\n{message}");
}
smtp.connectivity.set_working(context).await;
if let Err(err) = smtp
.connect_configured(context)
.await
.context("Failed to open SMTP connection")
{
smtp.last_send_error = Some(format!("{err:#}"));
return SendResult::Retry;
}
let send_result = smtp.send(context, recipients, message.as_bytes()).await;
smtp.last_send_error = send_result.as_ref().err().map(|e| e.to_string());
let status = match send_result {
Err(crate::smtp::send::Error::SmtpSend(err)) => {
// Remote error, retry later.
info!(context, "SMTP failed to send: {:?}.", &err);
let res = match err {
async_smtp::error::Error::Permanent(ref response) => {
// Workaround for incorrectly configured servers returning permanent errors
// instead of temporary ones.
let maybe_transient = match response.code {
// Sometimes servers send a permanent error when actually it is a temporary error
// For documentation see <https://tools.ietf.org/html/rfc3463>
Code {
category: Category::MailSystem,
detail: Detail::Zero,
..
} => {
// Ignore status code 5.5.0, see <https://support.delta.chat/t/every-other-message-gets-stuck/877/2>
// Maybe incorrectly configured Postfix milter with "reject" instead of "tempfail", which returns
// "550 5.5.0 Service unavailable" instead of "451 4.7.1 Service unavailable - try again later".
//
// Other enhanced status codes, such as Postfix
// "550 5.1.1 <foobar@example.org>: Recipient address rejected: User unknown in local recipient table"
// are not ignored.
response.first_word() == Some("5.5.0")
}
_ => false,
};
if maybe_transient {
info!(context, "Permanent error that is likely to actually be transient, postponing retry for later.");
SendResult::Retry
} else {
info!(context, "Permanent error, message sending failed.");
// If we do not retry, add an info message to the chat.
// Yandex error "554 5.7.1 [2] Message rejected under suspicion of SPAM; https://ya.cc/..."
// should definitely go here, because user has to open the link to
// resume message sending.
SendResult::Failure(format_err!("Permanent SMTP error: {}", err))
}
}
async_smtp::error::Error::Transient(ref response) => {
// We got a transient 4xx response from SMTP server.
// Give some time until the server-side error maybe goes away.
if let Some(first_word) = response.first_word() {
if first_word.ends_with(".1.1")
|| first_word.ends_with(".1.2")
|| first_word.ends_with(".1.3")
{
// Sometimes we receive transient errors that should be permanent.
// Any extended smtp status codes like x.1.1, x.1.2 or x.1.3 that we
// receive as a transient error are misconfigurations of the smtp server.
// See <https://tools.ietf.org/html/rfc3463#section-3.2>
info!(context, "Received extended status code {first_word} for a transient error. This looks like a misconfigured SMTP server, let's fail immediately.");
SendResult::Failure(format_err!("Permanent SMTP error: {}", err))
} else {
info!(
context,
"Transient error with status code {first_word}, postponing retry for later."
);
SendResult::Retry
}
} else {
info!(
context,
"Transient error without status code, postponing retry for later."
);
SendResult::Retry
}
}
_ => {
info!(
context,
"Message sending failed without error returned by the server, retry later."
);
SendResult::Retry
}
};
// this clears last_success info
info!(context, "Failed to send message over SMTP, disconnecting.");
smtp.disconnect();
res
}
Err(crate::smtp::send::Error::Envelope(err)) => {
// Local error, job is invalid, do not retry.
smtp.disconnect();
warn!(context, "SMTP job is invalid: {err:#}.");
SendResult::Failure(err)
}
Err(crate::smtp::send::Error::NoTransport) => {
// Should never happen.
// It does not even make sense to disconnect here.
error!(context, "SMTP job failed because SMTP has no transport.");
SendResult::Failure(format_err!("SMTP has not transport"))
}
Err(crate::smtp::send::Error::Other(err)) => {
// Local error, job is invalid, do not retry.
smtp.disconnect();
warn!(context, "Unable to load SMTP job: {err:#}.");
SendResult::Failure(err)
}
Ok(()) => SendResult::Success,
};
if let SendResult::Failure(err) = &status {
if let Some(msg_id) = msg_id {
// We couldn't send the message, so mark it as failed
match Message::load_from_db(context, msg_id).await {
Ok(mut msg) => {
if let Err(err) =
message::set_msg_failed(context, &mut msg, &err.to_string()).await
{
error!(context, "Failed to mark {msg_id} as failed: {err:#}.");
}
}
Err(err) => {
error!(
context,
"Failed to load {msg_id} to mark it as failed: {err:#}."
);
}
}
}
}
status
}
/// Sends message identified by `smtp` table rowid over SMTP connection.
///
/// Removes row if the message should not be retried, otherwise increments retry count.
pub(crate) async fn send_msg_to_smtp(
context: &Context,
smtp: &mut Smtp,
rowid: i64,
) -> anyhow::Result<()> {
if let Err(err) = smtp
.connect_configured(context)
.await
.context("SMTP connection failure")
{
smtp.last_send_error = Some(format!("{err:#}"));
return Err(err);
}
// Increase retry count as soon as we have an SMTP connection. This ensures that the message is
// eventually removed from the queue by exceeding retry limit even in case of an error that
// keeps happening early in the message sending code, e.g. failure to read the message from the
// database.
context
.sql
.execute("UPDATE smtp SET retries=retries+1 WHERE id=?", (rowid,))
.await
.context("failed to update retries count")?;
let (body, recipients, msg_id, retries) = context
.sql
.query_row(
"SELECT mime, recipients, msg_id, retries FROM smtp WHERE id=?",
(rowid,),
|row| {
let mime: String = row.get(0)?;
let recipients: String = row.get(1)?;
let msg_id: MsgId = row.get(2)?;
let retries: i64 = row.get(3)?;
Ok((mime, recipients, msg_id, retries))
},
)
.await?;
if retries > 6 {
let mut msg = Message::load_from_db(context, msg_id).await?;
message::set_msg_failed(context, &mut msg, "Number of retries exceeded the limit.").await?;
context
.sql
.execute("DELETE FROM smtp WHERE id=?", (rowid,))
.await
.context("Failed to remove message with exceeded retry limit from smtp table")?;
return Ok(());
}
info!(
context,
"Try number {retries} to send message {msg_id} (entry {rowid}) over SMTP."
);
let recipients_list = recipients
.split(' ')
.filter_map(
|addr| match async_smtp::EmailAddress::new(addr.to_string()) {
Ok(addr) => Some(addr),
Err(err) => {
warn!(context, "Invalid recipient: {} {:?}.", addr, err);
None
}
},
)
.collect::<Vec<_>>();
let status = smtp_send(context, &recipients_list, body.as_str(), smtp, Some(msg_id)).await;
match status {
SendResult::Retry => {}
SendResult::Success => {
context
.sql
.execute("DELETE FROM smtp WHERE id=?", (rowid,))
.await?;
}
SendResult::Failure(ref err) => {
if err.to_string().contains("Invalid unencrypted mail") {
let res = context
.sql
.query_row_optional(
"SELECT chat_id, timestamp FROM msgs WHERE id=?;",
(msg_id,),
|row| Ok((row.get::<_, ChatId>(0)?, row.get::<_, i64>(1)?)),
)
.await?;
if let Some((chat_id, timestamp_sort)) = res {
let addr = context.get_config(Config::ConfiguredAddr).await?;
let text = unencrypted_email(
context,
addr.unwrap_or_default()
.split('@')
.nth(1)
.unwrap_or_default(),
)
.await;
add_info_msg_with_cmd(
context,
chat_id,
&text,
crate::mimeparser::SystemMessage::InvalidUnencryptedMail,
timestamp_sort,
None,
None,
None,
)
.await?;
};
}
context
.sql
.execute("DELETE FROM smtp WHERE id=?", (rowid,))
.await?;
}
};
match status {
SendResult::Retry => Err(format_err!("Retry")),
SendResult::Success => {
if !context
.sql
.exists("SELECT COUNT(*) FROM smtp WHERE msg_id=?", (msg_id,))
.await?
{
msg_id.set_delivered(context).await?;
}
Ok(())
}
SendResult::Failure(err) => Err(format_err!("{}", err)),
}
}
/// Attempts to send queued MDNs.
async fn send_mdns(context: &Context, connection: &mut Smtp) -> Result<()> {
loop {
if !context.ratelimit.read().await.can_send() {
info!(context, "Ratelimiter does not allow sending MDNs now.");
return Ok(());
}
let more_mdns = send_mdn(context, connection).await?;
if !more_mdns {
// No more MDNs to send or one of them failed.
return Ok(());
}
}
}
/// Tries to send all messages currently in `smtp`, `smtp_status_updates` and `smtp_mdns` tables.
pub(crate) async fn send_smtp_messages(context: &Context, connection: &mut Smtp) -> Result<()> {
let ratelimited = if context.ratelimit.read().await.can_send() {
// add status updates and sync messages to end of sending queue
context.flush_status_updates().await?;
false
} else {
true
};
let rowids = context
.sql
.query_map(
"SELECT id FROM smtp ORDER BY id ASC",
(),
|row| {
let rowid: i64 = row.get(0)?;
Ok(rowid)
},
|rowids| {
rowids
.collect::<std::result::Result<Vec<_>, _>>()
.map_err(Into::into)
},
)
.await?;
info!(context, "Selected rows from SMTP queue: {rowids:?}.");
for rowid in rowids {
send_msg_to_smtp(context, connection, rowid)
.await
.context("Failed to send message")?;
}
// although by slow sending, ratelimit may have been expired meanwhile,
// do not attempt to send MDNs if ratelimited happened before on status-updates/sync:
// instead, let the caller recall this function so that more important status-updates/sync are sent out.
if !ratelimited {
send_mdns(context, connection)
.await
.context("Failed to send MDNs")?;
}
Ok(())
}
/// Tries to send MDN for message identified by `rfc724_mdn` to `contact_id`.
///
/// Attempts to aggregate additional MDNs for `contact_id` into sent MDN.
///
/// On failure returns an error without removing any `smtp_mdns` entries, the caller is responsible
/// for removing the corresponding entry to prevent endless loop in case the entry is invalid, e.g.
/// points to non-existent message or contact.
///
/// Returns true on success, false on temporary error.
async fn send_mdn_rfc724_mid(
context: &Context,
rfc724_mid: &str,
contact_id: ContactId,
smtp: &mut Smtp,
) -> Result<bool> {
let contact = Contact::get_by_id(context, contact_id).await?;
if contact.is_blocked() {
return Err(format_err!("Contact is blocked"));
}
// Try to aggregate additional MDNs into this MDN.
let additional_rfc724_mids: Vec<String> = context
.sql
.query_map(
"SELECT rfc724_mid
FROM smtp_mdns
WHERE from_id=? AND rfc724_mid!=?",
(contact_id, &rfc724_mid),
|row| {
let rfc724_mid: String = row.get(0)?;
Ok(rfc724_mid)
},
|rows| rows.collect::<Result<Vec<_>, _>>().map_err(Into::into),
)
.await?
.into_iter()
.collect();
let mimefactory = MimeFactory::from_mdn(
context,
contact_id,
rfc724_mid.to_string(),
additional_rfc724_mids.clone(),
)
.await?;
let rendered_msg = mimefactory.render(context).await?;
let body = rendered_msg.message;
let addr = contact.get_addr();
let recipient = async_smtp::EmailAddress::new(addr.to_string())
.map_err(|err| format_err!("invalid recipient: {} {:?}", addr, err))?;
let recipients = vec![recipient];
match smtp_send(context, &recipients, &body, smtp, None).await {
SendResult::Success => {
info!(context, "Successfully sent MDN for {rfc724_mid}.");
context
.sql
.execute("DELETE FROM smtp_mdns WHERE rfc724_mid = ?", (rfc724_mid,))
.await?;
if !additional_rfc724_mids.is_empty() {
let q = format!(
"DELETE FROM smtp_mdns WHERE rfc724_mid IN({})",
sql::repeat_vars(additional_rfc724_mids.len())
);
context
.sql
.execute(&q, rusqlite::params_from_iter(additional_rfc724_mids))
.await?;
}
Ok(true)
}
SendResult::Retry => {
info!(
context,
"Temporary SMTP failure while sending an MDN for {rfc724_mid}."
);
Ok(false)
}
SendResult::Failure(err) => Err(err),
}
}
/// Tries to send a single MDN. Returns true if more MDNs should be sent.
async fn send_mdn(context: &Context, smtp: &mut Smtp) -> Result<bool> {
if !context.should_send_mdns().await? {
context.sql.execute("DELETE FROM smtp_mdns", []).await?;
return Ok(false);
}
info!(context, "Sending MDNs.");
context
.sql
.execute("DELETE FROM smtp_mdns WHERE retries > 6", [])
.await?;
let Some(msg_row) = context
.sql
.query_row_optional(
"SELECT rfc724_mid, from_id FROM smtp_mdns ORDER BY retries LIMIT 1",
[],
|row| {
let rfc724_mid: String = row.get(0)?;
let from_id: ContactId = row.get(1)?;
Ok((rfc724_mid, from_id))
},
)
.await?
else {
return Ok(false);
};
let (rfc724_mid, contact_id) = msg_row;
context
.sql
.execute(
"UPDATE smtp_mdns SET retries=retries+1 WHERE rfc724_mid=?",
(rfc724_mid.clone(),),
)
.await
.context("Failed to update MDN retries count")?;
match send_mdn_rfc724_mid(context, &rfc724_mid, contact_id, smtp).await {
Err(err) => {
// If there is an error, for example there is no message corresponding to the msg_id in the
// database, do not try to send this MDN again.
warn!(
context,
"Error sending MDN for {rfc724_mid}, removing it: {err:#}."
);
context
.sql
.execute("DELETE FROM smtp_mdns WHERE rfc724_mid = ?", (rfc724_mid,))
.await?;
Err(err)
}
Ok(false) => {
bail!("Temporary error while sending an MDN");
}
Ok(true) => {
// Successfully sent MDN.
Ok(true)
}
}
}