1package smtpserver

2

3import (

4 "context"

5 "fmt"

6

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

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

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

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

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

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

13)

14

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

16func queueDSN(ctx context.Context, log mlog.Log, c *conn, rcptTo smtp.Path, m dsn.Message, requireTLS bool) error {

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

18 if err != nil {

19 return err

20 }

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

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

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

24

25 var bufUTF8 []byte

26 if c.smtputf8 {

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

28 if err != nil {

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

30 } else {

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

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

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

34 }

35 }

36

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

38 if err != nil {

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

40 }

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

42

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

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

45 }

46

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

48 // message instead of causing delivery loops.

49 // ../rfc/3464:433

50 const has8bit = false

51 const smtputf8 = false

52 var reqTLS *bool

53 if requireTLS {

54 reqTLS = &requireTLS

55 }

56 qm := queue.MakeMsg("", smtp.Path{}, rcptTo, has8bit, smtputf8, int64(len(buf)), m.MessageID, nil, reqTLS)

57 qm.DSNUTF8 = bufUTF8

58 if err := queue.Add(ctx, c.log, &qm, f); err != nil {

59 return err

60 }

61 return nil

62}

63