mox!

smtpserver/dsn.go

@@ -0,0 +1,56 @@
+package smtpserver
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/mjl-/mox/dsn"
+	"github.com/mjl-/mox/queue"
+	"github.com/mjl-/mox/smtp"
+	"github.com/mjl-/mox/store"
+)
+
+// compose dsn message and add it to the queue for delivery to rcptTo.
+func queueDSN(c *conn, rcptTo smtp.Path, m dsn.Message) error {
+	buf, err := m.Compose(c.log, false)
+	if err != nil {
+		return err
+	}
+	var bufUTF8 []byte
+	if c.smtputf8 {
+		bufUTF8, err = m.Compose(c.log, true)
+		if err != nil {
+			c.log.Errorx("composing dsn with utf-8 for incoming delivery for unknown user, continuing with ascii-only dsn", err)
+		}
+	}
+
+	f, err := store.CreateMessageTemp("smtp-dsn")
+	if err != nil {
+		return fmt.Errorf("creating temp file: %w", err)
+	}
+	defer func() {
+		if f != nil {
+			if err := os.Remove(f.Name()); err != nil {
+				c.log.Errorx("removing temporary dsn message file", err)
+			}
+			f.Close()
+		}
+	}()
+	if _, err := f.Write([]byte(buf)); err != nil {
+		return fmt.Errorf("writing dsn file: %w", err)
+	}
+
+	// Queue DSN with null reverse path so failures to deliver will eventually drop the
+	// message instead of causing delivery loops.
+	// ../rfc/3464:433
+	const has8bit = false
+	const smtputf8 = false
+	if err := queue.Add(c.log, "", smtp.Path{}, rcptTo, has8bit, smtputf8, int64(len(buf)), nil, f, bufUTF8, true); err != nil {
+		return err
+	}
+	if err := f.Close(); err != nil {
+		c.log.Errorx("closing dsn file", err)
+	}
+	f = nil
+	return nil
+}