1package http

2

3import (

4 "log/slog"

5 "net"

6 "net/http"

7 "strings"

8 "time"

9

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

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

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

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

14)

15

16func mtastsPolicyHandle(w http.ResponseWriter, r *http.Request) {

17 log := func() mlog.Log {

18 return pkglog.WithContext(r.Context())

19 }

20

21 host := strings.ToLower(r.Host)

22 if !strings.HasPrefix(host, "mta-sts.") {

23 http.NotFound(w, r)

24 return

25 }

26 host = strings.TrimPrefix(host, "mta-sts.")

27 nhost, _, err := net.SplitHostPort(host)

28 if err == nil {

29 // Only relevant for when host has a port.

30 host = nhost

31 }

32 domain, err := dns.ParseDomain(host)

33 if err != nil {

34 log().Errorx("mtasts policy request: bad domain", err, slog.String("host", host))

35 http.NotFound(w, r)

36 return

37 }

38

39 conf, _ := mox.Conf.Domain(domain)

40 sts := conf.MTASTS

41 if sts == nil {

42 http.NotFound(w, r)

43 return

44 }

45

46 var mxs []mtasts.MX

47 for _, s := range sts.MX {

48 var mx mtasts.MX

49 if strings.HasPrefix(s, "*.") {

50 mx.Wildcard = true

51 s = s[2:]

52 }

53 d, err := dns.ParseDomain(s)

54 if err != nil {

55 log().Errorx("bad domain in mtasts config", err, slog.String("domain", s))

56 http.Error(w, "500 - internal server error - invalid domain in configuration", http.StatusInternalServerError)

57 return

58 }

59 mx.Domain = d

60 mxs = append(mxs, mx)

61 }

62 if len(mxs) == 0 {

63 mxs = []mtasts.MX{{Domain: mox.Conf.Static.HostnameDomain}}

64 }

65

66 policy := mtasts.Policy{

67 Version: "STSv1",

68 Mode: sts.Mode,

69 MaxAgeSeconds: int(sts.MaxAge / time.Second),

70 MX: mxs,

71 }

72 w.Header().Set("Content-Type", "text/plain")

73 w.Header().Set("Cache-Control", "no-cache, max-age=0")

74 _, _ = w.Write([]byte(policy.String()))

75}

76