Do not propagate TcpListener.accept() errors

Errors produced by the socket may not be necessarily fatal, meaning that
while a connection might be dropped the process should be able to resume
execution as if nothing happened and accept the next connection.

Error handling for accept() has been copied from NGINX's [1].

[1] https://stackoverflow.com/questions/76955978/which-socket-accept-errors-are-fatal

Signed-off-by: Mroik <mroik@delayed.space>

1 files changed, 15 insertions, 1 deletions

diff --git a/src/smtp_server.rs b/src/smtp_server.rs
index bacf8eb..e6c0efc 100644
--- a/src/smtp_server.rs
+++ b/src/smtp_server.rs
@@ -27,7 +27,21 @@ impl SmtpServer {
     pub async fn run(&mut self, tx_processor: Sender<Mail>) -> Result<()> {
         self.running = true;
         while self.running {
-            let (stream, addr) = self.listener.accept()?;
+            let (stream, addr) = match self.listener.accept() {
+                Ok(v) => v,
+                Err(e) => match e.raw_os_error() {
+                    Some(libc::EMFILE | libc::ENFILE) => return Err(anyhow::Error::from(e)),
+                    Some(libc::ECONNABORTED) => {
+                        log::error!("{}", e);
+                        continue;
+                    }
+                    Some(libc::EAGAIN) => continue,
+                    _ => {
+                        log::warn!("{}", e);
+                        continue;
+                    }
+                },
+            };
             let session = SessionHandler {
                 addr,
                 tx_processor: tx_processor.clone(),