Update SMTP status codes (#1109)

Author: mdecimus

crates/jmap/src/api/form.rs

@@ -101,7 +101,7 @@ impl FormHandler for Server {
             if let Some(domain) = from_email.rsplit_once('@').and_then(|(local, domain)| {
                 if !local.is_empty()
                     && domain.contains('.')
-                    && psl::suffix(domain.as_bytes()).is_some()
+                    && psl::domain(domain.as_bytes()).is_some_and(|d| d.suffix().typ().is_some())
                 {
                     Some(domain)
                 } else {

crates/smtp/src/inbound/auth.rs

@@ -204,7 +204,7 @@ impl<T: SessionStream> Session<T> {
                 SpanId = self.data.session_id,
             );
 
-            self.write(b"421 4.3.0 Too many authentication errors, disconnecting.\r\n")
+            self.write(b"455 4.3.0 Too many authentication errors, disconnecting.\r\n")
                 .await?;
             Err(())
         }

crates/smtp/src/inbound/data.rs

@@ -850,7 +850,7 @@ impl<T: SessionStream> Session<T> {
                     Limit = self.data.messages_sent
                 );
 
-                self.write(b"451 4.4.5 Maximum number of messages per session exceeded.\r\n")
+                self.write(b"452 4.4.5 Maximum number of messages per session exceeded.\r\n")
                     .await?;
                 Ok(false)
             }

crates/smtp/src/inbound/mail.rs

@@ -513,7 +513,7 @@ impl<T: SessionStream> Session<T> {
             );
 
             self.data.mail_from = None;
-            self.write(b"451 4.4.5 Rate limit exceeded, try again later.\r\n")
+            self.write(b"452 4.4.5 Rate limit exceeded, try again later.\r\n")
                 .await
         }
     }

crates/smtp/src/inbound/rcpt.rs

@@ -50,7 +50,7 @@ impl<T: SessionStream> Session<T> {
                 SpanId = self.data.session_id,
                 Limit = self.params.rcpt_max,
             );
-            return self.write(b"451 4.5.3 Too many recipients.\r\n").await;
+            return self.write(b"455 4.5.3 Too many recipients.\r\n").await;
         }
 
         // Verify parameters
@@ -347,7 +347,7 @@ impl<T: SessionStream> Session<T> {
                                 return self
                                     .write(
                                         concat!(
-                                            "422 4.2.2 Greylisted, please try ",
+                                            "452 4.2.2 Greylisted, please try ",
                                             "again in a few moments.\r\n"
                                         )
                                         .as_bytes(),
@@ -385,7 +385,7 @@ impl<T: SessionStream> Session<T> {
 
             self.data.rcpt_to.pop();
             return self
-                .write(b"451 4.4.5 Rate limit exceeded, try again later.\r\n")
+                .write(b"452 4.4.5 Rate limit exceeded, try again later.\r\n")
                 .await;
         }
 
@@ -448,7 +448,7 @@ impl<T: SessionStream> Session<T> {
         if !has_too_many_errors {
             self.write(response).await
         } else {
-            self.write(b"421 4.3.0 Too many errors, disconnecting.\r\n")
+            self.write(b"451 4.3.0 Too many errors, disconnecting.\r\n")
                 .await?;
             Err(())
         }

crates/smtp/src/inbound/spawn.rs

@@ -169,7 +169,7 @@ impl<T: SessionStream> Session<T> {
                                         }
                                     } else if bytes_read > self.data.bytes_left {
                                         self
-                                            .write(format!("451 4.7.28 {} Session exceeded transfer quota.\r\n", self.hostname).as_bytes())
+                                            .write(format!("452 4.7.28 {} Session exceeded transfer quota.\r\n", self.hostname).as_bytes())
                                             .await
                                             .ok();
 
@@ -181,7 +181,7 @@ impl<T: SessionStream> Session<T> {
                                         break;
                                     } else {
                                         self
-                                            .write(format!("453 4.3.2 {} Session open for too long.\r\n", self.hostname).as_bytes())
+                                            .write(format!("421 4.3.2 {} Session open for too long.\r\n", self.hostname).as_bytes())
                                             .await
                                             .ok();
 
@@ -246,7 +246,7 @@ impl<T: SessionStream> Session<T> {
                         Reason = "Server shutting down",
                         CausedBy = trc::location!()
                     );
-                    self.write(b"421 4.3.0 Server shutting down.\r\n").await.ok();
+                    self.write(format!("421 4.3.0 {} Server shutting down.\r\n", self.hostname).as_bytes()).await.ok();
                     break;
                 }
             };