DNS over TLS and HTTPS set up in one step

jarl encrypted-dns setup (and the Encrypted DNS page) finds or obtains a
certificate for the host name, checks that nothing else listens on the
DoT and DoH ports at the chosen addresses (offering a free DoH port), and
stages named's tls statement and listeners as one change, keeping port 53
where it was when there was no listen-on, plus the host name's records in
the private views (local to the view in a linked zone). Status shows what
to give Android, Linux, Firefox, Chrome and Windows clients. A tls
statement with missing files is refused (tls_file_missing), and a
certificate named uses can't be deleted. docs/encrypted-dns.md, e2e with
real DoT and DoH queries.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/certs/manager.go

@@ -336,6 +336,9 @@ func (m *Manager) Update(ctx context.Context, name string, in Input, p *auth.Pri
 	if err := m.checkUses(ctx, c); err != nil {
 		return nil, err
 	}
+	if before.HasUse(model.CertUseDNS) && !c.HasUse(model.CertUseDNS) && m.namedUses(ctx, m.FilesDir(c.Name)) {
+		return nil, inputErr("named's configuration uses certificate %s (a tls statement names its files), so it keeps the dns use: take it out of named first (jarl encrypted-dns disable)", c.Name)
+	}
 	if c.Source == model.CertSourceFile && (c.CertFile != before.CertFile || c.KeyFile != before.KeyFile) {
 		if _, err := m.readFiles(c); err != nil {
 			return nil, inputErr("%v", err)
@@ -373,6 +376,9 @@ func (m *Manager) Delete(ctx context.Context, name string, p *auth.Principal) er
 	if err != nil {
 		return err
 	}
+	if c.HasUse(model.CertUseDNS) && m.namedUses(ctx, m.FilesDir(c.Name)) {
+		return inputErr("named's configuration uses certificate %s (a tls statement names its files): take it out first (jarl encrypted-dns disable, or remove the tls statement)", c.Name)
+	}
 	if err := m.store.DeleteCertificate(ctx, c.ID); err != nil {
 		return err
 	}

internal/encdns/encdns.go

@@ -0,0 +1,395 @@
+// Package encdns sets up DNS over TLS (DoT) and DNS over HTTPS (DoH) in
+// named (docs/encrypted-dns.md): a tls statement naming a certificate Jarl
+// manages, and listen-on statements for port 853 (DoT) and the DoH port.
+// Its state is read from named's configuration, so what the setup stages
+// stays ordinary, visible configuration.
+package encdns
+
+import (
+	"fmt"
+	"net/netip"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"jarl/internal/engine"
+	"jarl/internal/model"
+	"jarl/internal/namedconf"
+)
+
+// Prefix starts the names of the tls statements the setup writes.
+const Prefix = "jarl-"
+
+// DoTPort is the port for DNS over TLS (RFC 7858).
+const DoTPort = 853
+
+// Listener is a listen-on or listen-on-v6 statement.
+type Listener struct {
+	OptionID int64    `json:"option_id"`
+	V6       bool     `json:"v6"`
+	Port     int      `json:"port"`           // as written; 0 when it isn't
+	TLS      string   `json:"tls,omitempty"`  // tls statement ("" for plain DNS)
+	HTTP     string   `json:"http,omitempty"` // http endpoints: DNS over HTTPS
+	Addrs    []string `json:"addresses"`      // the address match list
+}
+
+// EffectivePort is the port named listens on: as written, or its
+// default for the kind of listener.
+func (l Listener) EffectivePort() int {
+	switch {
+	case l.Port != 0:
+		return l.Port
+	case l.HTTP != "" && l.TLS != "" && l.TLS != "none":
+		return 443
+	case l.HTTP != "":
+		return 80
+	case l.TLS != "":
+		return DoTPort
+	}
+	return 53
+}
+
+// Kind is plain, dot or doh.
+func (l Listener) Kind() string {
+	switch {
+	case l.HTTP != "":
+		return "doh"
+	case l.TLS != "" && l.TLS != "none":
+		return "dot"
+	}
+	return "plain"
+}
+
+// Managed reports whether the setup wrote the listener.
+func (l Listener) Managed() bool { return strings.HasPrefix(l.TLS, Prefix) }
+
+// Listeners returns the server's listen-on and listen-on-v6 statements.
+func Listeners(st *model.State) []Listener {
+	var out []Listener
+	for _, o := range st.ScopedOptions(model.ScopeOptions, 0) {
+		if o.Name != "listen-on" && o.Name != "listen-on-v6" {
+			continue
+		}
+		l, err := parseListener(o.Name, o.Value)
+		if err != nil {
+			continue
+		}
+		l.OptionID, l.V6 = o.ID, o.Name == "listen-on-v6"
+		out = append(out, l)
+	}
+	return out
+}
+
+func parseListener(name, value string) (Listener, error) {
+	var l Listener
+	stmt, err := namedconf.ParseOptionValue(name, value)
+	if err != nil {
+		return l, err
+	}
+	items := stmt.Items[1:]
+	for i := 0; i < len(items); i++ {
+		it := items[i]
+		if it.Block != nil {
+			for _, s := range it.Block.Stmts {
+				l.Addrs = append(l.Addrs, namedconf.Compact(s.Items))
+			}
+			continue
+		}
+		if it.Value == nil || i+1 >= len(items) || items[i+1].Value == nil {
+			continue
+		}
+		arg := items[i+1].Value.Text
+		switch strings.ToLower(it.Value.Text) {
+		case "port":
+			l.Port, _ = strconv.Atoi(arg)
+		case "tls":
+			l.TLS = arg
+		case "http":
+			l.HTTP = arg
+		}
+		i++
+	}
+	return l, nil
+}
+
+// TLSBlock is a top-level tls statement.
+type TLSBlock struct {
+	OptionID int64  `json:"option_id"`
+	Name     string `json:"name"`
+	CertFile string `json:"cert_file"`
+	KeyFile  string `json:"key_file"`
+}
+
+// TLSBlocks returns the top-level tls statements.
+func TLSBlocks(st *model.State) []TLSBlock {
+	var out []TLSBlock
+	for _, o := range st.ScopedOptions(model.ScopeTopLevel, 0) {
+		if o.Name != "tls" {
+			continue
+		}
+		stmt, err := namedconf.ParseOptionValue("tls", o.Value)
+		if err != nil {
+			continue
+		}
+		b := TLSBlock{OptionID: o.ID, Name: stmt.Arg(0)}
+		if blk := stmt.FirstBlock(); blk != nil {
+			for _, s := range blk.Stmts {
+				switch s.Keyword() {
+				case "cert-file":
+					b.CertFile = s.Arg(0)
+				case "key-file":
+					b.KeyFile = s.Arg(0)
+				}
+			}
+		}
+		out = append(out, b)
+	}
+	return out
+}
+
+// Endpoint is an address and port named serves DoT or DoH on.
+type Endpoint struct {
+	Address string `json:"address"`
+	Port    int    `json:"port"`
+}
+
+// Status is what is set up.
+type Status struct {
+	Enabled bool `json:"enabled"`
+	// TLS is the tls statement the setup wrote, and Certificate the
+	// certificate it names (a Jarl certificate's name, when it is one).
+	TLS         *TLSBlock  `json:"tls,omitempty"`
+	Certificate string     `json:"certificate,omitempty"`
+	DoT         []Endpoint `json:"dot"`
+	DoH         []Endpoint `json:"doh"`
+	// Listeners are all listen-on statements, the setup's and others.
+	Listeners []Listener `json:"listeners"`
+	// Other are DoT or DoH listeners written by hand.
+	Other bool `json:"other,omitempty"`
+}
+
+// GetStatus reads the setup from the configuration. certDir is where Jarl
+// writes certificates for named (certificates.dir).
+func GetStatus(st *model.State, certDir string) Status {
+	s := Status{Listeners: Listeners(st), DoT: []Endpoint{}, DoH: []Endpoint{}}
+	if s.Listeners == nil {
+		s.Listeners = []Listener{}
+	}
+	for _, b := range TLSBlocks(st) {
+		if strings.HasPrefix(b.Name, Prefix) {
+			b := b
+			s.TLS = &b
+			if dir := filepath.Dir(b.CertFile); filepath.Dir(dir) == filepath.Clean(certDir) {
+				s.Certificate = filepath.Base(dir)
+			}
+			break
+		}
+	}
+	for _, l := range s.Listeners {
+		if l.Kind() == "plain" {
+			continue
+		}
+		if !l.Managed() {
+			s.Other = true
+			continue
+		}
+		for _, a := range l.Addrs {
+			e := Endpoint{Address: a, Port: l.EffectivePort()}
+			if l.Kind() == "doh" {
+				s.DoH = append(s.DoH, e)
+			} else {
+				s.DoT = append(s.DoT, e)
+			}
+		}
+	}
+	s.Enabled = len(s.DoT)+len(s.DoH) > 0
+	return s
+}
+
+// Setup is what to set up.
+type Setup struct {
+	// Hostname is the name clients connect to (the certificate's).
+	Hostname string `json:"hostname"`
+	// Certificate is the Jarl certificate (with the dns use) to serve.
+	Certificate string `json:"certificate"`
+	// Addresses are the addresses of this server to listen on.
+	Addresses []string `json:"addresses"`
+	DoT       bool     `json:"dot"`
+	DoH       bool     `json:"doh"`
+	DoHPort   int      `json:"doh_port"` // default 443
+	DoTPort   int      `json:"dot_port"` // default 853 (clients expect it)
+	// Views get the hostname's A/AAAA records (default: none). In a
+	// linked zone they are local to the view.
+	Views []string `json:"views"`
+}
+
+// Plan returns the requests that set up encrypted DNS as s says,
+// replacing an earlier setup, and notes for the user. certDir is where
+// the certificate's files are.
+func Plan(st *model.State, s Setup, certDir string) ([]engine.Request, []string, error) {
+	var notes []string
+	if !s.DoT && !s.DoH {
+		return nil, nil, fmt.Errorf("choose DNS over TLS, DNS over HTTPS or both")
+	}
+	if s.DoHPort == 0 {
+		s.DoHPort = 443
+	}
+	if s.DoTPort == 0 {
+		s.DoTPort = DoTPort
+	}
+	for _, p := range []int{s.DoHPort, s.DoTPort} {
+		if p < 1 || p > 65535 || p == 53 {
+			return nil, nil, fmt.Errorf("port %d: use a free port other than 53", p)
+		}
+	}
+	if s.DoT && s.DoH && s.DoHPort == s.DoTPort {
+		return nil, nil, fmt.Errorf("DoT and DoH need different ports (both are %d)", s.DoHPort)
+	}
+	if s.Certificate == "" {
+		return nil, nil, fmt.Errorf("choose the certificate to serve")
+	}
+	host := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(s.Hostname), "."))
+	if host == "" || !strings.Contains(host, ".") {
+		return nil, nil, fmt.Errorf("give the host name clients connect to, e.g. dns.example.com")
+	}
+	var v4, v6 []string
+	for _, a := range s.Addresses {
+		ip, err := netip.ParseAddr(strings.TrimSpace(a))
+		if err != nil {
+			return nil, nil, fmt.Errorf("%q isn't an address of this server", a)
+		}
+		ip = ip.Unmap()
+		if ip.IsUnspecified() {
+			return nil, nil, fmt.Errorf("listen on this server's addresses, not on %s (that would include public ones)", ip)
+		}
+		if ip.Is4() {
+			v4 = append(v4, ip.String())
+		} else {
+			v6 = append(v6, ip.String())
+		}
+	}
+	if len(v4)+len(v6) == 0 {
+		return nil, nil, fmt.Errorf("choose at least one address to listen on")
+	}
+	tlsName := Prefix + s.Certificate
+	dir := filepath.Join(certDir, s.Certificate)
+	tlsValue := fmt.Sprintf(`%s { cert-file "%s"; key-file "%s"; protocols { TLSv1.2; TLSv1.3; }; }`,
+		tlsName, filepath.Join(dir, "fullchain.pem"), filepath.Join(dir, "privkey.pem"))
+
+	var reqs []engine.Request
+	// Take out the earlier setup's listeners and tls statements.
+	current := Listeners(st)
+	for _, l := range current {
+		if l.Managed() {
+			reqs = append(reqs, engine.NewRequest(engine.OpOptionDelete, l.OptionID, nil))
+		}
+	}
+	haveTLS := false
+	for _, b := range TLSBlocks(st) {
+		switch {
+		case b.Name == tlsName:
+			haveTLS = true
+			reqs = append(reqs, engine.NewRequest(engine.OpOptionUpdate, b.OptionID, engine.OptionInput{Value: model.Ptr(tlsValue)}))
+		case strings.HasPrefix(b.Name, Prefix):
+			reqs = append(reqs, engine.NewRequest(engine.OpOptionDelete, b.OptionID, nil))
+		}
+	}
+	if !haveTLS {
+		reqs = append(reqs, option(model.ScopeTopLevel, "tls", tlsValue))
+	}
+	// named listens on port 53 everywhere only while there is no
+	// listen-on statement at all: adding the first one for DoT would end
+	// that, so keep it explicitly.
+	plain := func(v6 bool) bool {
+		for _, l := range current {
+			if l.V6 == v6 && !l.Managed() && l.Kind() == "plain" {
+				return true
+			}
+		}
+		return false
+	}
+	add := func(name string, addrs []string) {
+		if len(addrs) == 0 {
+			return
+		}
+		list := "{ " + strings.Join(addrs, "; ") + "; }"
+		if !plain(name == "listen-on-v6") {
+			reqs = append(reqs, option(model.ScopeOptions, name, "{ any; }"))
+			notes = append(notes, fmt.Sprintf("named listened on port 53 on every address by default; %s { any; } keeps that, as the first %s statement would otherwise end it", name, name))
+		}
+		if s.DoT {
+			reqs = append(reqs, option(model.ScopeOptions, name, fmt.Sprintf("port %d tls %s %s", s.DoTPort, tlsName, list)))
+		}
+		if s.DoH {
+			reqs = append(reqs, option(model.ScopeOptions, name, fmt.Sprintf("port %d tls %s http default %s", s.DoHPort, tlsName, list)))
+		}
+	}
+	add("listen-on", v4)
+	add("listen-on-v6", v6)
+
+	// The host name's addresses, in the views asked for.
+	fqdn := host + "."
+	for _, vn := range s.Views {
+		v := st.ViewByName(vn)
+		if v == nil {
+			return nil, nil, fmt.Errorf("view %q does not exist", vn)
+		}
+		z := zoneFor(st, fqdn, v.ID)
+		if z == nil {
+			notes = append(notes, fmt.Sprintf("view %s has no zone for %s, so no address records were added there; clients must find it some other way", v.Name, host))
+			continue
+		}
+		var local *bool
+		if z.LinkGroup != 0 {
+			local = model.Ptr(true)
+		}
+		for _, set := range []struct {
+			typ   string
+			addrs []string
+		}{{"A", v4}, {"AAAA", v6}} {
+			if len(set.addrs) == 0 {
+				continue
+			}
+			reqs = append(reqs, engine.NewRequest(engine.OpRRSetReplace, 0, engine.RRSetInput{ZoneID: z.ID, Name: fqdn, Type: set.typ, Data: set.addrs, Local: local}))
+		}
+	}
+	return reqs, notes, nil
+}
+
+func option(scope, name, value string) engine.Request {
+	return engine.NewRequest(engine.OpOptionCreate, 0, engine.OptionInput{Scope: model.Ptr(scope), Name: model.Ptr(name), Value: model.Ptr(value)})
+}
+
+// zoneFor returns the primary zone in a view that holds name.
+func zoneFor(st *model.State, name string, viewID int64) *model.Zone {
+	var best *model.Zone
+	for _, z := range st.ZonesInView(viewID) {
+		if z.Type == model.ZonePrimary && (name == z.Name || strings.HasSuffix(name, "."+z.Name)) && (best == nil || len(z.Name) > len(best.Name)) {
+			best = z
+		}
+	}
+	return best
+}
+
+// Disable returns the requests that take the setup out: its listeners and
+// tls statement. Plain listeners and the host name's records stay.
+func Disable(st *model.State) []engine.Request {
+	var reqs []engine.Request
+	for _, l := range Listeners(st) {
+		if l.Managed() {
+			reqs = append(reqs, engine.NewRequest(engine.OpOptionDelete, l.OptionID, nil))
+		}
+	}
+	for _, b := range TLSBlocks(st) {
+		if strings.HasPrefix(b.Name, Prefix) {
+			reqs = append(reqs, engine.NewRequest(engine.OpOptionDelete, b.OptionID, nil))
+		}
+	}
+	return reqs
+}
+
+// Private reports whether an address is private (RFC 1918, ULA, ...).
+func Private(a netip.Addr) bool {
+	a = a.Unmap()
+	return a.IsPrivate() || a.IsLoopback() || a.IsLinkLocalUnicast() || netip.MustParsePrefix("100.64.0.0/10").Contains(a)
+}

internal/encdns/encdns_test.go

@@ -0,0 +1,188 @@
+package encdns
+
+import (
+	"context"
+	"io"
+	"log/slog"
+	"net/netip"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+	"testing"
+
+	"jarl/internal/auth"
+	"jarl/internal/engine"
+	"jarl/internal/model"
+	"jarl/internal/render"
+	"jarl/internal/store"
+)
+
+type env struct {
+	t       *testing.T
+	eng     *engine.Engine
+	st      *store.Store
+	certDir string
+}
+
+func newEnv(t *testing.T) *env {
+	dir := t.TempDir()
+	st, err := store.Open(filepath.Join(dir, "jarl.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { st.Close() })
+	eng := engine.New(st, nil, engine.Config{
+		Paths:      render.Paths{ConfigDir: filepath.Join(dir, "etc"), ZoneDir: filepath.Join(dir, "zones"), CacheDir: filepath.Join(dir, "cache")},
+		StagingDir: filepath.Join(dir, "staging"), NoReload: true, SkipCheck: true,
+	}, slog.New(slog.NewTextHandler(io.Discard, nil)))
+	e := &env{t: t, eng: eng, st: st, certDir: filepath.Join(dir, "tls")}
+	os.MkdirAll(filepath.Join(e.certDir, "dns"), 0o755)
+	os.WriteFile(filepath.Join(e.certDir, "dns", "fullchain.pem"), []byte("x"), 0o644)
+	os.WriteFile(filepath.Join(e.certDir, "dns", "privkey.pem"), []byte("x"), 0o600)
+	e.submit(engine.NewRequest(engine.OpSettingsUpdate, 0, engine.SettingsInput{Nameservers: &[]string{"ns1.example.net."}}),
+		engine.NewRequest(engine.OpViewCreate, 0, engine.ViewInput{Name: model.Ptr("internal"), MatchClients: &[]string{"10.0.0.0/8"}}),
+		engine.NewRequest(engine.OpViewCreate, 0, engine.ViewInput{Name: model.Ptr("external"), MatchClients: &[]string{"any"}}))
+	e.submit(engine.NewRequest(engine.OpZoneCreate, 0, engine.ZoneInput{Name: model.Ptr("example.com"), View: model.Ptr("internal")}))
+	return e
+}
+
+func (e *env) submit(reqs ...engine.Request) *engine.Result {
+	e.t.Helper()
+	res, err := e.eng.Submit(context.Background(), reqs, auth.System, "test", "", engine.ApplyOptions{})
+	if err != nil {
+		e.t.Fatalf("%v (%+v)", err, res)
+	}
+	return res
+}
+
+func (e *env) state() *model.State {
+	st, err := e.st.LoadState(context.Background())
+	if err != nil {
+		e.t.Fatal(err)
+	}
+	return st
+}
+
+func values(st *model.State, scope, name string) []string {
+	var out []string
+	for _, o := range st.ScopedOptions(scope, 0) {
+		if o.Name == name {
+			out = append(out, o.Value)
+		}
+	}
+	return out
+}
+
+func TestSetup(t *testing.T) {
+	e := newEnv(t)
+	setup := Setup{Hostname: "dns.example.com", Certificate: "dns", Addresses: []string{"10.0.10.5", "2001:db8::5"}, DoT: true, DoH: true, Views: []string{"internal", "external"}}
+	reqs, notes, err := Plan(e.state(), setup, e.certDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	e.submit(reqs...)
+	st := e.state()
+	tls := values(st, model.ScopeTopLevel, "tls")
+	if len(tls) != 1 || !strings.HasPrefix(tls[0], "jarl-dns {") || !strings.Contains(tls[0], filepath.Join(e.certDir, "dns", "fullchain.pem")) {
+		t.Errorf("tls = %q", tls)
+	}
+	// The plain listeners named had by default are kept explicitly.
+	want4 := []string{"{ any; }", "port 853 tls jarl-dns { 10.0.10.5; }", "port 443 tls jarl-dns http default { 10.0.10.5; }"}
+	if got := values(st, model.ScopeOptions, "listen-on"); !slices.Equal(got, want4) {
+		t.Errorf("listen-on = %q, want %q", got, want4)
+	}
+	if got := values(st, model.ScopeOptions, "listen-on-v6"); len(got) != 3 || got[0] != "{ any; }" {
+		t.Errorf("listen-on-v6 = %q", got)
+	}
+	if len(notes) != 3 || !strings.Contains(strings.Join(notes, " "), "external has no zone") {
+		t.Errorf("notes = %q", notes)
+	}
+	// The host name's addresses in the internal view.
+	z := st.FindZone("example.com.", st.ViewByName("internal").ID)
+	var addrs []string
+	for _, r := range st.ZoneRecords(z.ID) {
+		if r.Name == "dns.example.com." {
+			addrs = append(addrs, r.Type+" "+r.Data)
+		}
+	}
+	if !slices.Equal(addrs, []string{"A 10.0.10.5", "AAAA 2001:db8::5"}) {
+		t.Errorf("records = %q", addrs)
+	}
+	s := GetStatus(st, e.certDir)
+	if !s.Enabled || s.Certificate != "dns" || len(s.DoT) != 2 || len(s.DoH) != 2 || s.DoH[0].Port != 443 || s.Other {
+		t.Errorf("status = %+v", s)
+	}
+
+	// Setting up again replaces the setup: DoT only, one address, and the
+	// plain listeners aren't doubled.
+	reqs, _, err = Plan(st, Setup{Hostname: "dns.example.com", Certificate: "dns", Addresses: []string{"10.0.10.5"}, DoT: true}, e.certDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	e.submit(reqs...)
+	st = e.state()
+	if got := values(st, model.ScopeOptions, "listen-on"); !slices.Equal(got, []string{"{ any; }", "port 853 tls jarl-dns { 10.0.10.5; }"}) {
+		t.Errorf("after the second setup: %q", got)
+	}
+	if got := values(st, model.ScopeOptions, "listen-on-v6"); !slices.Equal(got, []string{"{ any; }"}) {
+		t.Errorf("listen-on-v6 after the second setup: %q", got)
+	}
+	if got := values(st, model.ScopeTopLevel, "tls"); len(got) != 1 {
+		t.Errorf("tls statements: %q", got)
+	}
+
+	// Off: the setup's listeners and tls statement go, the rest stays.
+	e.submit(Disable(st)...)
+	st = e.state()
+	if got := values(st, model.ScopeOptions, "listen-on"); !slices.Equal(got, []string{"{ any; }"}) || len(values(st, model.ScopeTopLevel, "tls")) != 0 || GetStatus(st, e.certDir).Enabled {
+		t.Errorf("after disabling: listen-on %q tls %q", got, values(st, model.ScopeTopLevel, "tls"))
+	}
+}
+
+func TestSetupRefuses(t *testing.T) {
+	e := newEnv(t)
+	st := e.state()
+	for _, s := range []Setup{
+		{Hostname: "dns.example.com", Certificate: "dns", Addresses: []string{"10.0.10.5"}},                         // neither DoT nor DoH
+		{Hostname: "dns.example.com", Certificate: "dns", Addresses: []string{"0.0.0.0"}, DoT: true},                // every address
+		{Hostname: "dns.example.com", Certificate: "dns", DoT: true},                                                // no address
+		{Hostname: "dns.example.com", Certificate: "dns", Addresses: []string{"10.0.10.5"}, DoH: true, DoHPort: 53}, // port 53
+		{Hostname: "dns", Certificate: "dns", Addresses: []string{"10.0.10.5"}, DoT: true},                          // not a host name
+	} {
+		if _, _, err := Plan(st, s, e.certDir); err == nil {
+			t.Errorf("accepted %+v", s)
+		}
+	}
+	// A tls statement whose files are missing is refused by validation.
+	_, err := e.eng.Submit(context.Background(), []engine.Request{engine.NewRequest(engine.OpOptionCreate, 0, engine.OptionInput{
+		Scope: model.Ptr(model.ScopeTopLevel), Name: model.Ptr("tls"), Value: model.Ptr(`x { cert-file "/nonexistent/c.pem"; key-file "/nonexistent/k.pem"; }`)})},
+		auth.System, "test", "", engine.ApplyOptions{})
+	if err == nil || !strings.Contains(err.Error(), "doesn't exist") {
+		t.Errorf("missing files: %v", err)
+	}
+}
+
+func TestPorts(t *testing.T) {
+	s, err := parseProcAddr("0100007F:0035")
+	if err != nil || s.Addr != netip.MustParseAddr("127.0.0.1") || s.Port != 53 {
+		t.Errorf("v4: %+v %v", s, err)
+	}
+	s, err = parseProcAddr("00000000000000000000000001000000:01BB")
+	if err != nil || s.Addr != netip.MustParseAddr("::1") || s.Port != 443 {
+		t.Errorf("v6: %+v %v", s, err)
+	}
+	e := newEnv(t)
+	old := ListeningSockets
+	t.Cleanup(func() { ListeningSockets = old })
+	ListeningSockets = func() ([]Socket, error) {
+		return []Socket{{netip.MustParseAddr("0.0.0.0"), 443}, {netip.MustParseAddr("10.0.10.5"), 8443}, {netip.MustParseAddr("::"), 853}}, nil
+	}
+	c, err := PortCheck(e.state(), []string{"10.0.10.5"}, []int{853, 443, 8443}, []string{"0.0.0.0:443"})
+	if err != nil || len(c) != 3 || c[1].What != "jarld (Jarl's web UI and API)" || c[2].What != "another program" {
+		t.Errorf("conflicts = %+v %v", c, err)
+	}
+	if p := FreeDoHPort(e.state(), []string{"10.0.10.5"}, nil); p != 4443 {
+		t.Errorf("free DoH port = %d, want 4443", p)
+	}
+}

internal/encdns/ports.go

@@ -0,0 +1,149 @@
+package encdns
+
+import (
+	"bufio"
+	"encoding/hex"
+	"fmt"
+	"net/netip"
+	"os"
+	"strconv"
+	"strings"
+
+	"jarl/internal/model"
+)
+
+// Socket is a listening TCP socket on this host.
+type Socket struct {
+	Addr netip.Addr
+	Port int
+}
+
+// ListeningSockets reads the host's listening TCP sockets from
+// /proc/net/tcp and tcp6 (Linux; nil elsewhere). It needs no privileges
+// and binds nothing. Tests replace it.
+var ListeningSockets = func() ([]Socket, error) {
+	var out []Socket
+	for _, f := range []string{"/proc/net/tcp", "/proc/net/tcp6"} {
+		socks, err := parseProcNet(f)
+		if err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return nil, err
+		}
+		out = append(out, socks...)
+	}
+	return out, nil
+}
+
+func parseProcNet(path string) ([]Socket, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	var out []Socket
+	sc := bufio.NewScanner(f)
+	sc.Scan() // header
+	for sc.Scan() {
+		fields := strings.Fields(sc.Text())
+		if len(fields) < 4 || fields[3] != "0A" { // 0A: LISTEN
+			continue
+		}
+		s, err := parseProcAddr(fields[1])
+		if err == nil {
+			out = append(out, s)
+		}
+	}
+	return out, sc.Err()
+}
+
+// parseProcAddr parses "0100007F:0035": the address in 32-bit words of
+// host byte order (little-endian here), then the port.
+func parseProcAddr(s string) (Socket, error) {
+	ha, hp, ok := strings.Cut(s, ":")
+	if !ok {
+		return Socket{}, fmt.Errorf("bad address %q", s)
+	}
+	b, err := hex.DecodeString(ha)
+	if err != nil || (len(b) != 4 && len(b) != 16) {
+		return Socket{}, fmt.Errorf("bad address %q", s)
+	}
+	for i := 0; i+4 <= len(b); i += 4 {
+		b[i], b[i+1], b[i+2], b[i+3] = b[i+3], b[i+2], b[i+1], b[i]
+	}
+	addr, _ := netip.AddrFromSlice(b)
+	port, err := strconv.ParseUint(hp, 16, 16)
+	if err != nil {
+		return Socket{}, err
+	}
+	return Socket{Addr: addr.Unmap(), Port: int(port)}, nil
+}
+
+// Conflict is something else listening where a listener would go.
+type Conflict struct {
+	Address string `json:"address"`
+	Port    int    `json:"port"`
+	What    string `json:"what"` // who it is, when Jarl knows
+}
+
+// PortCheck says which of addresses × ports something else listens on
+// already. named's own listeners (the setup's, now) and jarld's (known
+// listen addresses) are told apart.
+func PortCheck(st *model.State, addresses []string, ports []int, jarld []string) ([]Conflict, error) {
+	socks, err := ListeningSockets()
+	if err != nil {
+		return nil, err
+	}
+	// What named listens on now with DoT or DoH (it will again).
+	ours := map[string]bool{}
+	for _, l := range Listeners(st) {
+		if l.Kind() != "plain" {
+			for _, a := range l.Addrs {
+				ours[a+"#"+strconv.Itoa(l.EffectivePort())] = true
+			}
+		}
+	}
+	jarldOn := map[string]bool{}
+	for _, l := range jarld {
+		jarldOn[l] = true
+	}
+	var out []Conflict
+	for _, as := range addresses {
+		a, err := netip.ParseAddr(as)
+		if err != nil {
+			continue
+		}
+		a = a.Unmap()
+		for _, p := range ports {
+			if ours[a.String()+"#"+strconv.Itoa(p)] {
+				continue
+			}
+			for _, s := range socks {
+				if s.Port != p || !(s.Addr == a || s.Addr.IsUnspecified() && s.Addr.Is4() == a.Is4() || s.Addr.IsUnspecified() && s.Addr.Is6()) {
+					continue
+				}
+				what := "another program"
+				for l := range jarldOn {
+					if strings.HasSuffix(l, ":"+strconv.Itoa(p)) {
+						what = "jarld (Jarl's web UI and API)"
+					}
+				}
+				out = append(out, Conflict{Address: a.String(), Port: p, What: what})
+				break
+			}
+		}
+	}
+	return out, nil
+}
+
+// FreeDoHPort returns the first of the usual DoH ports nothing listens on
+// at the addresses (0 when none is free).
+func FreeDoHPort(st *model.State, addresses []string, jarld []string) int {
+	for _, p := range []int{443, 8443, 4443, 9443} {
+		if c, err := PortCheck(st, addresses, []int{p}, jarld); err == nil && len(c) == 0 {
+			return p
+		}
+	}
+	return 0
+}

internal/server/h_encdns.go

@@ -0,0 +1,236 @@
+package server
+
+import (
+	"net/http"
+	"net/netip"
+	"slices"
+	"strconv"
+	"strings"
+
+	"jarl/internal/auth"
+	"jarl/internal/certs"
+	"jarl/internal/encdns"
+	"jarl/internal/model"
+	"jarl/internal/nscheck"
+)
+
+// DNS over TLS and HTTPS (docs/encrypted-dns.md).
+
+type encAddress struct {
+	Address string `json:"address"`
+	Private bool   `json:"private"`
+}
+
+type encView struct {
+	Name    string `json:"name"`
+	Public  bool   `json:"public"`
+	HasZone bool   `json:"has_zone,omitempty"` // has a zone for the host name
+}
+
+type encCert struct {
+	Name     string       `json:"name"`
+	Names    []string     `json:"names"`
+	Domains  []string     `json:"domains"`
+	DNS      bool         `json:"dns"` // has the dns use
+	Status   certs.Status `json:"status"`
+	Obtained bool         `json:"obtained"`
+}
+
+type encStatus struct {
+	encdns.Status
+	// Hostname is the name clients connect to (the certificate's first).
+	Hostname string `json:"hostname,omitempty"`
+	// DoTHost and DoHURL are what to give clients.
+	DoTHost string `json:"dot_host,omitempty"`
+	DoHURL  string `json:"doh_url,omitempty"`
+	// For the setup form.
+	Addresses    []encAddress `json:"addresses"`
+	Views        []encView    `json:"views"`
+	Certificates []encCert    `json:"certificates"`
+}
+
+func (s *Server) encReady(p *auth.Principal, write bool) error {
+	if err := require(p, auth.Action{Resource: auth.ResOptions, Write: write}); err != nil {
+		return err
+	}
+	if s.cfg.Certs == nil {
+		return &httpError{http.StatusNotFound, "disabled", "certificates aren't available in this jarld"}
+	}
+	return nil
+}
+
+// localAddrs returns this host's addresses (a test may replace it).
+var localAddrs = nscheck.LocalAddrs
+
+// encryptedDNS: GET /encrypted-dns.
+func (s *Server) encryptedDNS(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	if err := s.encReady(p, false); err != nil {
+		return err
+	}
+	st, err := s.store.LoadState(r.Context())
+	if err != nil {
+		return err
+	}
+	m := s.cfg.Certs
+	out := encStatus{Status: encdns.GetStatus(st, m.FilesDir("")), Addresses: []encAddress{}, Views: []encView{}, Certificates: []encCert{}}
+	all, err := m.List(r.Context())
+	if err != nil {
+		return err
+	}
+	for _, c := range all {
+		out.Certificates = append(out.Certificates, encCert{Name: c.Name, Names: c.Names, Domains: c.Domains, DNS: c.HasUse(model.CertUseDNS),
+			Status: m.StatusOf(c), Obtained: c.NotAfter != nil})
+		if c.Name == out.Certificate {
+			for _, n := range append(c.Names, c.Domains...) {
+				if !strings.HasPrefix(n, "*.") {
+					out.Hostname = n
+					break
+				}
+			}
+		}
+	}
+	if out.Hostname != "" {
+		if len(out.DoT) > 0 {
+			out.DoTHost = out.Hostname
+			if out.DoT[0].Port != encdns.DoTPort {
+				out.DoTHost += ":" + strconv.Itoa(out.DoT[0].Port)
+			}
+		}
+		if len(out.DoH) > 0 {
+			out.DoHURL = "https://" + out.Hostname
+			if out.DoH[0].Port != 443 {
+				out.DoHURL += ":" + strconv.Itoa(out.DoH[0].Port)
+			}
+			out.DoHURL += "/dns-query"
+		}
+	}
+	seen := map[netip.Addr]bool{}
+	for _, a := range localAddrs() {
+		a = a.Unmap()
+		if seen[a] || a.IsLinkLocalUnicast() {
+			continue
+		}
+		seen[a] = true
+		out.Addresses = append(out.Addresses, encAddress{Address: a.String(), Private: encdns.Private(a)})
+	}
+	slices.SortFunc(out.Addresses, func(a, b encAddress) int { return strings.Compare(a.Address, b.Address) })
+	host := strings.TrimSuffix(r.URL.Query().Get("hostname"), ".")
+	if host == "" {
+		host = out.Hostname
+	}
+	for _, x := range s.eng.Exposures(st) {
+		if x.View == "" {
+			continue
+		}
+		v := encView{Name: x.View, Public: x.Public}
+		if host != "" {
+			if vv := st.ViewByName(x.View); vv != nil {
+				for _, z := range st.ZonesInView(vv.ID) {
+					if z.Type == model.ZonePrimary && (host+"." == z.Name || strings.HasSuffix(host+".", "."+z.Name)) {
+						v.HasZone = true
+					}
+				}
+			}
+		}
+		out.Views = append(out.Views, v)
+	}
+	writeJSON(w, http.StatusOK, out)
+	return nil
+}
+
+// encryptedDNSCheck: POST /encrypted-dns/check {"addresses", "dot", "doh",
+// "doh_port"} says what already listens where the listeners would go.
+func (s *Server) encryptedDNSCheck(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	if err := s.encReady(p, false); err != nil {
+		return err
+	}
+	var in encdns.Setup
+	if err := decodeJSON(r, &in); err != nil {
+		return err
+	}
+	st, err := s.store.LoadState(r.Context())
+	if err != nil {
+		return err
+	}
+	if in.DoHPort == 0 {
+		in.DoHPort = 443
+	}
+	if in.DoTPort == 0 {
+		in.DoTPort = encdns.DoTPort
+	}
+	var ports []int
+	if in.DoT {
+		ports = append(ports, in.DoTPort)
+	}
+	if in.DoH {
+		ports = append(ports, in.DoHPort)
+	}
+	conflicts, err := encdns.PortCheck(st, in.Addresses, ports, s.cfg.Listen)
+	out := map[string]any{"conflicts": conflicts}
+	if err != nil {
+		out["error"] = "can't see which ports are in use: " + err.Error()
+	}
+	if conflicts == nil {
+		out["conflicts"] = []encdns.Conflict{}
+	}
+	if in.DoH {
+		out["free_doh_port"] = encdns.FreeDoHPort(st, in.Addresses, s.cfg.Listen)
+	}
+	writeJSON(w, http.StatusOK, out)
+	return nil
+}
+
+// encryptedDNSSetup: POST /encrypted-dns stages (or applies) the setup.
+func (s *Server) encryptedDNSSetup(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	if err := s.encReady(p, true); err != nil {
+		return err
+	}
+	var in encdns.Setup
+	if err := decodeJSON(r, &in); err != nil {
+		return err
+	}
+	c, err := s.cfg.Certs.Get(r.Context(), in.Certificate)
+	if err != nil {
+		return certErr(err)
+	}
+	switch {
+	case !c.HasUse(model.CertUseDNS):
+		return badRequest("certificate %s doesn't have the dns use, so named can't read it: jarl cert update %s --use dns (and keep its other uses)", c.Name, c.Name)
+	case c.NotAfter == nil:
+		return conflict("certificate %s hasn't been obtained yet (%s); set up encrypted DNS once it has", c.Name, s.cfg.Certs.StatusOf(c).Message)
+	case in.Hostname != "" && !certs.Covers(c.Names, []string{in.Hostname}):
+		return badRequest("certificate %s is for %s, not %s: clients would reject it", c.Name, strings.Join(c.Names, ", "), in.Hostname)
+	}
+	st, err := s.store.LoadState(r.Context())
+	if err != nil {
+		return err
+	}
+	reqs, notes, err := encdns.Plan(st, in, s.cfg.Certs.FilesDir(""))
+	if err != nil {
+		return badRequest("%v", err)
+	}
+	what := []string{}
+	if in.DoT {
+		what = append(what, "DNS over TLS")
+	}
+	if in.DoH {
+		what = append(what, "DNS over HTTPS")
+	}
+	return s.mutateNotes(w, r, p, "set up "+strings.Join(what, " and ")+" for "+in.Hostname, reqs, nil, notes)
+}
+
+// encryptedDNSDisable: DELETE /encrypted-dns.
+func (s *Server) encryptedDNSDisable(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	if err := s.encReady(p, true); err != nil {
+		return err
+	}
+	st, err := s.store.LoadState(r.Context())
+	if err != nil {
+		return err
+	}
+	reqs := encdns.Disable(st)
+	if len(reqs) == 0 {
+		return conflict("encrypted DNS isn't set up")
+	}
+	return s.mutate(w, r, p, "turn DNS over TLS and HTTPS off", reqs, nil)
+}

internal/server/routes.go

@@ -172,6 +172,10 @@ func (s *Server) routes() {
 	m.HandleFunc("DELETE "+p+"/certificates/{name}", s.authed(s.certDelete))
 	m.HandleFunc("POST "+p+"/certificates/{name}/issue", s.authed(s.certIssue))
 	m.HandleFunc("POST "+p+"/certificates/{name}/check", s.authed(s.certCheck))
+	m.HandleFunc("GET "+p+"/encrypted-dns", s.authed(s.encryptedDNS))
+	m.HandleFunc("POST "+p+"/encrypted-dns", s.authed(s.encryptedDNSSetup))
+	m.HandleFunc("DELETE "+p+"/encrypted-dns", s.authed(s.encryptedDNSDisable))
+	m.HandleFunc("POST "+p+"/encrypted-dns/check", s.authed(s.encryptedDNSCheck))
 	m.HandleFunc("GET "+p+"/exposure", s.authed(s.exposure))
 	m.HandleFunc("POST "+p+"/exposure/fix", s.authed(s.exposureFix))
 	m.HandleFunc("POST "+p+"/exposure/ack", s.authed(s.exposureAck(true)))
@@ -253,6 +257,11 @@ func changesetTarget(r *http.Request) (int64, error) {
 // mutate applies (or stages, or previews) requests and writes the
 // response. object, if set, returns the resulting object to include.
 func (s *Server) mutate(w http.ResponseWriter, r *http.Request, p *auth.Principal, description string, reqs []engine.Request, object func(st *model.State, created int64) any) error {
+	return s.mutateNotes(w, r, p, description, reqs, object, nil)
+}
+
+// mutateNotes is mutate with notes for the user, shown as warnings.
+func (s *Server) mutateNotes(w http.ResponseWriter, r *http.Request, p *auth.Principal, description string, reqs []engine.Request, object func(st *model.State, created int64) any, notes []string) error {
 	csID, err := changesetTarget(r)
 	if err != nil {
 		return err
@@ -263,7 +272,7 @@ func (s *Server) mutate(w http.ResponseWriter, r *http.Request, p *auth.Principa
 			return err
 		}
 		res.Changeset.Ops = engine.RedactOps(res.Changeset.Ops)
-		writeJSON(w, http.StatusAccepted, api.MutationResponse{Staged: true, ChangesetID: csID, Changeset: raw(res.Changeset), Added: engine.RedactOps(res.Added), Warnings: res.Warnings, Problems: raw(res.Problems)})
+		writeJSON(w, http.StatusAccepted, api.MutationResponse{Staged: true, ChangesetID: csID, Changeset: raw(res.Changeset), Added: engine.RedactOps(res.Added), Warnings: append(notes, res.Warnings...), Problems: raw(res.Problems)})
 		return nil
 	}
 	opts := engine.ApplyOptions{DryRun: queryBool(r, "dry_run"), Force: queryBool(r, "force"), AcceptRisk: queryBool(r, "accept_risk")}
@@ -272,7 +281,7 @@ func (s *Server) mutate(w http.ResponseWriter, r *http.Request, p *auth.Principa
 		s.writeErr(w, r, err, res)
 		return nil
 	}
-	out := api.MutationResponse{Applied: res.Applied, DryRun: res.DryRun, ChangesetID: res.ChangesetID, Result: raw(res), Warnings: res.Warnings}
+	out := api.MutationResponse{Applied: res.Applied, DryRun: res.DryRun, ChangesetID: res.ChangesetID, Result: raw(res), Warnings: append(notes, res.Warnings...)}
 	if object != nil && res.Applied {
 		st, err := s.store.LoadState(r.Context())
 		if err == nil {

internal/validate/tls.go

@@ -0,0 +1,34 @@
+package validate
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+
+	"jarl/internal/model"
+	"jarl/internal/namedconf"
+)
+
+// checkTLSFiles checks that the files a top-level tls statement names
+// exist: named fails to load the whole configuration otherwise. (Files
+// jarld can't look at are left to named.)
+func (c *checker) checkTLSFiles() {
+	for _, o := range c.s.ScopedOptions(model.ScopeTopLevel, 0) {
+		if o.Name != "tls" {
+			continue
+		}
+		stmt, err := namedconf.ParseOptionValue("tls", o.Value)
+		if err != nil || stmt.FirstBlock() == nil {
+			continue
+		}
+		for _, s := range stmt.FirstBlock().Stmts {
+			switch s.Keyword() {
+			case "cert-file", "key-file", "ca-file", "dhparam-file":
+				path := s.Arg(0)
+				if _, err := os.Stat(path); errors.Is(err, fs.ErrNotExist) {
+					c.errf("tls_file_missing", "option", o.ID, "tls %s: %s %s doesn't exist, and named won't load its configuration without it (a certificate Jarl obtains is written once it has been obtained: jarl cert list)", stmt.Arg(0), s.Keyword(), path)
+				}
+			}
+		}
+	}
+}

internal/validate/validate.go

@@ -152,6 +152,7 @@ func State(s *model.State, opts Options) []Problem {
 	c.checkDNSSEC()
 	c.checkBlocking()
 	c.checkLinked()
+	c.checkTLSFiles()
 	c.applyAcks()
 	sortProblems(c.problems)
 	return c.problems

internal/web/static/assets/app.js

@@ -20,6 +20,7 @@ import * as stats from "./pages/stats.js";
 import * as blocking from "./pages/blocking.js";
 import * as exposure from "./pages/exposure.js";
 import * as certificates from "./pages/certificates.js";
+import * as encdns from "./pages/encdns.js";
 
 const routes = [
   { pattern: /^$/, page: dashboard, nav: "dashboard" },
@@ -41,6 +42,7 @@ const routes = [
   { pattern: /^blocking$/, page: blocking, nav: "blocking" },
   { pattern: /^exposure$/, page: exposure, nav: "exposure" },
   { pattern: /^certificates$/, page: certificates, nav: "certificates" },
+  { pattern: /^encrypted-dns$/, page: encdns, nav: "encdns" },
 ];
 
 const navItems = [
@@ -51,6 +53,7 @@ const navItems = [
   ["views", "#/views", "Views"],
   ["exposure", "#/exposure", "Exposure"],
   ["certificates", "#/certificates", "Certificates", "admin"],
+  ["encdns", "#/encrypted-dns", "Encrypted DNS", "admin"],
   ["acls", "#/acls", "ACLs"],
   ["keys", "#/keys", "TSIG keys"],
   ["options", "#/options", "Server options"],

internal/web/static/assets/pages/encdns.js

@@ -0,0 +1,225 @@
+// DNS over TLS and HTTPS for your clients (docs/encrypted-dns.md): what is
+// set up and what to give clients, and a setup that obtains the
+// certificate if needed, checks the ports and stages named's
+// configuration like any change.
+import { h, mount, field, input, badge, toast, errorBox, confirmDialog, copyBox, checkbox } from "../ui.js";
+import { api, get, change, describeResult, state } from "../api.js";
+import { rerender } from "../app.js";
+
+export async function render(el) {
+  if (!state.me.admin) {
+    mount(el, h("h1", null, "Encrypted DNS"), h("div", { class: "msg warn" }, "Only administrators can set up DNS over TLS and HTTPS."));
+    return;
+  }
+  const s = await get("/encrypted-dns");
+  const parts = [h("div", { class: "page-head" },
+    h("div", { class: "grow" }, h("h1", null, "Encrypted DNS"),
+      h("div", { class: "muted" }, "DNS over TLS (DoT) and DNS over HTTPS (DoH) for your own devices: phones, laptops and browsers ask this server over an encrypted connection, and get the same answers (and blocking) as over plain DNS. Clients get the view their address matches, as with plain DNS.")),
+    s.enabled ? h("div", { class: "actions" }, h("button", { class: "danger", onclick: disable }, "Turn off")) : null)];
+
+  if (s.enabled) parts.push(statusPanel(s));
+  if (s.other) parts.push(h("div", { class: "msg info" }, "named also has DoT or DoH listeners written by hand (Server options → listen-on). The setup leaves them alone."));
+  parts.push(setupPanel(s));
+  mount(el, parts);
+}
+
+function statusPanel(s) {
+  const eps = (list) => list.map((e) => e.address + " port " + e.port).join(", ");
+  const rows = [
+    h("dt", null, "Certificate"), h("dd", null, h("a", { href: "#/certificates" }, s.certificate || "?"), s.hostname ? " (" + s.hostname + ")" : null),
+    s.dot.length ? [h("dt", null, "DNS over TLS"), h("dd", { class: "mono" }, eps(s.dot))] : null,
+    s.doh.length ? [h("dt", null, "DNS over HTTPS"), h("dd", { class: "mono" }, eps(s.doh))] : null,
+  ];
+  const addr = (s.dot[0] || s.doh[0] || {}).address || "ADDRESS";
+  const dotPortArg = s.dot[0] && s.dot[0].port !== 853 ? " -p " + s.dot[0].port : "";
+  const clients = [];
+  if (s.dot_host) {
+    clients.push(h("h3", null, "DNS over TLS"), copyBox(s.dot_host),
+      h("ul", { class: "small" },
+        h("li", null, h("strong", null, "Android: "), "Settings → Network → Private DNS → hostname: ", h("code", null, s.hostname), ". Away from home Android can't reach this server and then resolves nothing, so use a VPN home (WireGuard) or switch Private DNS to Automatic when you leave."),
+        h("li", null, h("strong", null, "Linux (systemd-resolved): "), h("code", null, "DNS=" + addr + "#" + s.hostname), " and ", h("code", null, "DNSOverTLS=yes"), " in /etc/systemd/resolved.conf (", h("code", null, "opportunistic"), " falls back to plain DNS away from home)."),
+        h("li", null, h("strong", null, "Test: "), h("code", null, "kdig +tls-ca +tls-host=" + s.hostname + dotPortArg + " @" + addr + " example.com"))));
+  }
+  if (s.doh_url) {
+    clients.push(h("h3", null, "DNS over HTTPS"), copyBox(s.doh_url),
+      h("ul", { class: "small" },
+        h("li", null, h("strong", null, "Firefox: "), "Settings → Privacy & Security → DNS over HTTPS → Increased protection (falls back to normal DNS) → Custom: the URL above."),
+        h("li", null, h("strong", null, "Chrome, Edge: "), "Settings → Privacy and security → Security → Use secure DNS → custom: the URL above."),
+        h("li", null, h("strong", null, "Windows 11: "), "Settings → Network → your connection → DNS server assignment → Edit: " + addr + ", DNS over HTTPS on (manual template), the URL above."),
+        h("li", null, h("strong", null, "Test: "), h("code", null, "curl -s -H 'accept: application/dns-json' '" + s.doh_url + "?name=example.com'"), " (or ", h("code", null, "dig +https @" + addr + " example.com"), ")")));
+  }
+  return [
+    h("div", { class: "panel" }, h("h2", null, "Set up ", badge("on", "ok")), h("dl", { class: "kv" }, rows)),
+    h("div", { class: "panel" }, h("h2", null, "For your clients"),
+      h("p", { class: "muted small" }, "Clients check the certificate against the host name, so it must resolve to this server for them (Jarl added it to the private views you chose). Open the ports in the server's firewall for your networks only."),
+      clients),
+  ];
+}
+
+function setupPanel(s) {
+  const host = input({ value: s.hostname || "", placeholder: "dns.adbraun.lol", class: "mono", style: { maxWidth: "320px" } });
+  const certSel = h("select");
+  const dot = checkbox("DNS over TLS", s.enabled ? s.dot.length > 0 : true);
+  const doh = checkbox("DNS over HTTPS", s.enabled ? s.doh.length > 0 : true);
+  const dotPort = input({ type: "number", value: (s.dot[0] || {}).port || 853, style: { width: "90px" } });
+  const dohPort = input({ type: "number", value: (s.doh[0] || {}).port || 443, style: { width: "90px" } });
+  const current = new Set([...s.dot, ...s.doh].map((e) => e.address));
+  const picked = new Set(current);
+  const portOut = h("div");
+  const err = h("div");
+  const progress = h("div", { class: "muted small" });
+
+  // Addresses: one per row, nothing ticked (but the current setup's).
+  const addrRows = s.addresses.map((a) => pickRow(a.address, picked, [a.private ? h("span", { class: "muted" }, "private")
+    : a.address.includes(":") ? h("span", { class: "muted", title: "A global IPv6 address: reachable from the internet unless the firewall stops it" }, "global")
+    : badge("public", "warn")],
+    "Listen on " + a.address, () => checkPorts()));
+  // Views for the host name's records: the private ones that have its zone.
+  const viewPicked = new Set();
+  const viewBody = h("tbody");
+  const drawViews = (views) => {
+    viewPicked.clear();
+    mount(viewBody, views.map((v) => {
+      if (!v.public && v.has_zone) viewPicked.add(v.name);
+      return pickRow(v.name, viewPicked, [v.public ? badge("public", "warn") : h("span", { class: "muted" }, "private"), " ",
+        v.has_zone ? h("span", { class: "muted small" }, "has the zone") : h("span", { class: "muted small" }, "no zone for this name: skipped")], "Add the host name to view " + v.name);
+    }));
+  };
+  drawViews(s.views);
+
+  const fillCerts = () => {
+    const name = host.value.trim().toLowerCase().replace(/\.$/, "");
+    const fit = s.certificates.filter((c) => covers([...(c.names || []), ...(c.domains || [])], name));
+    mount(certSel,
+      fit.map((c) => h("option", { value: c.name, selected: c.name === s.certificate }, c.name + " (" + (c.names || c.domains).join(", ") + (c.obtained ? "" : ", not obtained yet") + ")")),
+      name ? h("option", { value: "" }, "Obtain a new certificate for " + name) : h("option", { value: "" }, "Type the host name first"));
+  };
+  fillCerts();
+  let viewTimer = null;
+  host.addEventListener("input", () => {
+    fillCerts();
+    clearTimeout(viewTimer);
+    viewTimer = setTimeout(async () => {
+      const r = await get("/encrypted-dns", { hostname: host.value.trim() }).catch(() => null);
+      if (r) drawViews(r.views);
+    }, 300);
+  });
+
+  let checkTimer = null, checkSeq = 0;
+  const checkPorts = () => {
+    clearTimeout(checkTimer);
+    checkTimer = setTimeout(async () => {
+      const seq = ++checkSeq;
+      if (!picked.size) { mount(portOut); return; }
+      const r = await api("POST", "/encrypted-dns/check", { body: body(false) }).catch((e) => ({ error: e.message, conflicts: [] }));
+      if (seq !== checkSeq) return;
+      const msgs = r.conflicts.map((c) => h("div", null, c.what + " listens on " + c.address + " port " + c.port + "."));
+      if (r.conflicts.some((c) => c.port === Number(dohPort.value)) && r.free_doh_port) {
+        msgs.push(h("div", null, "Port " + r.free_doh_port + " is free for DoH: ",
+          h("button", { type: "button", class: "small", onclick: () => { dohPort.value = r.free_doh_port; checkPorts(); } }, "Use " + r.free_doh_port)));
+      }
+      mount(portOut, r.error ? h("div", { class: "msg warn small" }, r.error)
+        : msgs.length ? h("div", { class: "msg err small" }, msgs)
+        : h("div", { class: "msg ok small" }, "The ports are free on the chosen addresses."));
+    }, 250);
+  };
+  for (const x of [dotPort, dohPort]) x.addEventListener("input", checkPorts);
+  for (const x of [dot, doh]) x.input.addEventListener("change", checkPorts);
+  if (picked.size) checkPorts();
+
+  const body = (full) => {
+    const b = { hostname: host.value.trim(), addresses: [...picked], dot: dot.input.checked, doh: doh.input.checked, dot_port: Number(dotPort.value) || 853, doh_port: Number(dohPort.value) || 443 };
+    if (full) { b.certificate = certSel.value; b.views = [...viewPicked]; }
+    return b;
+  };
+
+  const submit = async (btn) => {
+    mount(err);
+    const b = body(true);
+    if (!b.hostname) return mount(err, h("div", { class: "msg err" }, "Give the host name clients connect to."));
+    if (!b.addresses.length) return mount(err, h("div", { class: "msg err" }, "Choose at least one address to listen on."));
+    btn.disabled = true;
+    try {
+      if (!b.certificate) {
+        // Obtain one for the host name, for named, and wait for it.
+        b.certificate = b.hostname.split(".")[0].replace(/[^a-z0-9_-]/g, "-");
+        mount(progress, "Obtaining a certificate for " + b.hostname + " from the CA…");
+        await api("POST", "/certificates", { body: { name: b.certificate, domains: [b.hostname], uses: ["dns"] } });
+        await waitObtained(b.certificate, progress);
+      } else {
+        const c = await get("/certificates/" + encodeURIComponent(b.certificate));
+        if (!c.uses.includes("dns")) await api("PATCH", "/certificates/" + encodeURIComponent(b.certificate), { body: { uses: [...c.uses, "dns"] } });
+        if (!c.not_after) {
+          if (!c.issuing_since) await api("POST", "/certificates/" + encodeURIComponent(b.certificate) + "/issue", { body: {} });
+          await waitObtained(b.certificate, progress);
+        }
+      }
+      mount(progress, "Setting up named…");
+      const r = await change("POST", "/encrypted-dns", b);
+      toast(describeResult(r));
+      (r.warnings || []).forEach((w) => toast(w, "warn", 10000));
+      rerender();
+    } catch (e) {
+      mount(progress);
+      mount(err, errorBox(e));
+    } finally { btn.disabled = false; }
+  };
+
+  const go = h("button", { class: "primary", onclick: (e) => submit(e.target) }, s.enabled ? "Change setup" : "Set up");
+  return h("div", { class: "panel" },
+    h("h2", null, s.enabled ? "Change the setup" : "Set up"),
+    h("div", { class: "form-grid" },
+      field("Host name", host, "The name clients connect to. The certificate is for it, and it gets this server's addresses in the views below."),
+      field("Certificate", certSel, "One with this name, or a new one Jarl obtains and renews (docs/certificates.md)."),
+      field("Listen on", h("div", null, h("div", { class: "table-wrap" }, h("table", { class: "pick-list" }, h("tbody", null, addrRows))), portOut),
+        "This server's addresses on your own networks. A public address works too, but then anyone who reaches it can use these listeners, as with port 53 there."),
+      field("Serve", h("div", { class: "enc-ports" }, h("div", null, dot, " on port ", dotPort), h("div", null, doh, " on port ", dohPort, h("span", { class: "muted small" }, "  at /dns-query"))),
+        "Clients expect DoT on port 853. DoH can use any free port; 443 is the default, and needs nothing else listening there."),
+      field("Host name in views", h("div", { class: "table-wrap" }, h("table", { class: "pick-list" }, viewBody)),
+        "Where the host name gets the chosen addresses (A and AAAA), local to the view in a linked zone. Clients outside these views can't find it.")),
+    err, progress,
+    h("div", { class: "buttons" }, go));
+}
+
+// pickRow is a table row that toggles value in set when clicked.
+function pickRow(value, set, extra, label, onChange) {
+  const box = h("input", { type: "checkbox", checked: set.has(value), "aria-label": label });
+  const tr = h("tr", { class: "pick" + (set.has(value) ? " selected" : "") }, h("td", null, box), h("td", { class: "mono" }, value), h("td", null, extra));
+  box.addEventListener("change", () => {
+    if (box.checked) set.add(value); else set.delete(value);
+    tr.classList.toggle("selected", box.checked);
+    if (onChange) onChange();
+  });
+  tr.addEventListener("click", (e) => { if (e.target !== box) { box.checked = !box.checked; box.dispatchEvent(new Event("change")); } });
+  return tr;
+}
+
+function covers(names, host) {
+  if (!host) return false;
+  return names.some((n) => {
+    n = n.toLowerCase().replace(/\.$/, "");
+    if (n === host) return true;
+    return n.startsWith("*.") && host.split(".").slice(1).join(".") === n.slice(2);
+  });
+}
+
+async function waitObtained(name, progress) {
+  const started = Date.now();
+  for (;;) {
+    await new Promise((r) => setTimeout(r, 2500));
+    const c = await get("/certificates/" + encodeURIComponent(name));
+    if (!c.issuing_since) {
+      if (!c.not_after) throw new Error("Obtaining the certificate failed: " + (c.last_error || "see the Certificates page"));
+      return c;
+    }
+    mount(progress, "Obtaining a certificate for " + (c.domains || []).join(", ") + " from the CA… " + Math.round((Date.now() - started) / 1000) + "s (the challenges must reach every name server)");
+  }
+}
+
+async function disable() {
+  if (!await confirmDialog("Turn encrypted DNS off", "named stops serving DNS over TLS and HTTPS. The certificate and the host name's records stay.", "Turn off", "danger")) return;
+  try {
+    toast(describeResult(await change("DELETE", "/encrypted-dns")));
+    rerender();
+  } catch (e) { toast(e.message, "err", 8000); }
+}

internal/web/static/assets/style.css

@@ -518,3 +518,7 @@ td textarea.code { min-width: min(72ch, 50vw); }
 table.pick-list tr.pick { cursor: pointer; }
 table.pick-list tr.pick td:first-child { width: 2em; }
 table.pick-list tr.pick.selected { background: var(--accent-soft); }
+
+/* Encrypted DNS: a protocol per line with its port. */
+.enc-ports > div { margin: 2px 0; }
+.enc-ports input[type=number] { display: inline-block; }