1package smtpserver

2

3import (

4 "context"

5 "fmt"

6 "os"

7

8 "github.com/mjl-/mox/dsn"

9 "github.com/mjl-/mox/queue"

10 "github.com/mjl-/mox/smtp"

11 "github.com/mjl-/mox/store"

12)

13

14// compose dsn message and add it to the queue for delivery to rcptTo.

15func queueDSN(ctx context.Context, c *conn, rcptTo smtp.Path, m dsn.Message) error {

16 buf, err := m.Compose(c.log, false)

17 if err != nil {

18 return err

19 }

20 var bufUTF8 []byte

21 if c.smtputf8 {

22 bufUTF8, err = m.Compose(c.log, true)

23 if err != nil {

24 c.log.Errorx("composing dsn with utf-8 for incoming delivery for unknown user, continuing with ascii-only dsn", err)

25 }

26 }

27

28 f, err := store.CreateMessageTemp("smtp-dsn")

29 if err != nil {

30 return fmt.Errorf("creating temp file: %w", err)

31 }

32 defer func() {

33 if f != nil {

34 err := os.Remove(f.Name())

35 c.log.Check(err, "removing temporary dsn message file")

36 err = f.Close()

37 c.log.Check(err, "closing temporary dsn message file")

38 }

39 }()

40 if _, err := f.Write([]byte(buf)); err != nil {

41 return fmt.Errorf("writing dsn file: %w", err)

42 }

43

44 // Queue DSN with null reverse path so failures to deliver will eventually drop the

45 // message instead of causing delivery loops.

46 // ../rfc/3464:433

47 const has8bit = false

48 const smtputf8 = false

49 if _, err := queue.Add(ctx, c.log, "", smtp.Path{}, rcptTo, has8bit, smtputf8, int64(len(buf)), m.MessageID, nil, f, bufUTF8, true); err != nil {

50 return err

51 }

52 err = f.Close()

53 c.log.Check(err, "closing dsn file")

54 f = nil

55 return nil

56}

57