1package smtpserver

2

3import (

4 "context"

5 "fmt"

6 "time"

7

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

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

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

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

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

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

14)

15

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

17func queueDSN(ctx context.Context, log mlog.Log, c *conn, rcptTo smtp.Path, m dsn.Message, requireTLS bool) error {

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

19 if err != nil {

20 return err

21 }

22 bufDKIM, err := mox.DKIMSign(ctx, c.log, m.From, false, buf)

23 log.Check(err, "dkim signing dsn")

24 buf = append([]byte(bufDKIM), buf...)

25

26 var bufUTF8 []byte

27 if c.smtputf8 {

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

29 if err != nil {

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

31 } else {

32 bufUTF8DKIM, err := mox.DKIMSign(ctx, log, m.From, true, bufUTF8)

33 log.Check(err, "dkim signing dsn with utf8")

34 bufUTF8 = append([]byte(bufUTF8DKIM), bufUTF8...)

35 }

36 }

37

38 f, err := store.CreateMessageTemp(c.log, "smtp-dsn")

39 if err != nil {

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

41 }

42 defer store.CloseRemoveTempFile(c.log, f, "smtpserver dsn message")

43

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

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

46 }

47

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

49 // message instead of causing delivery loops.

50 // ../rfc/3464:433

51 const has8bit = false

52 const smtputf8 = false

53 var reqTLS *bool

54 if requireTLS {

55 reqTLS = &requireTLS

56 }

57 qm := queue.MakeMsg(smtp.Path{}, rcptTo, has8bit, smtputf8, int64(len(buf)), m.MessageID, nil, reqTLS, time.Now(), m.Subject)

58 qm.DSNUTF8 = bufUTF8

59 if err := queue.Add(ctx, c.log, mox.Conf.Static.Postmaster.Account, f, qm); err != nil {

60 return err

61 }

62 return nil

63}

64