edgeguard-native/internal/chrony/chrony.go

// Package chrony renders /etc/chrony/conf.d/edgeguard.conf from
// ntp_settings + ntp_pools and reloads chrony.service. Distro
// /etc/chrony/chrony.conf includes conf.d/* automatically — wir
// schreiben nur unseren drop-in.
package chrony

import (
	"bytes"
	"context"
	_ "embed"
	"fmt"
	"os"
	"strings"
	"text/template"

	"github.com/jackc/pgx/v5/pgxpool"

	"git.netcell-it.de/projekte/edgeguard-native/internal/configgen"
	"git.netcell-it.de/projekte/edgeguard-native/internal/models"
	ntpsvc "git.netcell-it.de/projekte/edgeguard-native/internal/services/ntp"
)

// ConfPath: distro chrony.conf includes /etc/chrony/conf.d/*.conf.
// Wir schreiben direkt rein. postinst legt die Datei initial mit
// chown edgeguard:edgeguard 0644 an damit der Renderer schreibt.
const ConfPath = "/etc/chrony/conf.d/edgeguard.conf"

//go:embed chrony.cfg.tpl
var cfgTpl string

var tpl = template.Must(template.New("chrony").Parse(cfgTpl))

type View struct {
	Settings        *models.NTPSettings
	Pools           []models.NTPPool
	ListenAddresses []string
	AllowACLs       []string
}

type Generator struct {
	Pool       *pgxpool.Pool
	Repo       *ntpsvc.Repo
	SkipReload bool
}

func New(pool *pgxpool.Pool) *Generator {
	return &Generator{Pool: pool, Repo: ntpsvc.New(pool)}
}

func (g *Generator) Name() string { return "chrony" }

// RenderToString renders the chrony config to a string without writing
// to disk or reloading the service. Used by the config-preview endpoint.
func (g *Generator) RenderToString(ctx context.Context) (string, error) {
	settings, err := g.Repo.GetSettings(ctx)
	if err != nil {
		return "", fmt.Errorf("settings: %w", err)
	}
	pools, err := g.Repo.ListPools(ctx)
	if err != nil {
		return "", fmt.Errorf("pools: %w", err)
	}
	view := View{
		Settings:        settings,
		Pools:           pools,
		ListenAddresses: filterNonLoopback(splitCSV(settings.ListenAddresses)),
		AllowACLs:       splitCSV(settings.AllowACL),
	}
	var body bytes.Buffer
	if err := tpl.Execute(&body, view); err != nil {
		return "", fmt.Errorf("template: %w", err)
	}
	return body.String(), nil
}

func (g *Generator) Render(ctx context.Context) error {
	settings, err := g.Repo.GetSettings(ctx)
	if err != nil {
		return fmt.Errorf("settings: %w", err)
	}
	pools, err := g.Repo.ListPools(ctx)
	if err != nil {
		return fmt.Errorf("pools: %w", err)
	}
	view := View{
		Settings:        settings,
		Pools:           pools,
		ListenAddresses: filterNonLoopback(splitCSV(settings.ListenAddresses)),
		AllowACLs:       splitCSV(settings.AllowACL),
	}

	var body bytes.Buffer
	if err := tpl.Execute(&body, view); err != nil {
		return fmt.Errorf("template: %w", err)
	}
	// Direct write (kein tmp+rename) — analog unbound, weil
	// /etc/chrony/conf.d/ root-owned ist und edgeguard nur die eine
	// Datei überschreiben darf (postinst chown).
	if err := os.WriteFile(ConfPath, body.Bytes(), 0o644); err != nil {
		return fmt.Errorf("write %s: %w", ConfPath, err)
	}
	if g.SkipReload {
		return nil
	}
	// chrony.service kennt kein 'systemctl reload' — nur restart.
	// ~200ms ohne NTP-Antworten beim Save, dafür neue conf wirksam.
	return configgen.RestartService("chrony")
}

func splitCSV(s string) []string {
	out := []string{}
	for _, part := range strings.Split(s, ",") {
		p := strings.TrimSpace(part)
		if p != "" {
			out = append(out, p)
		}
	}
	return out
}

// filterNonLoopback wirft 127.x / ::1 raus — wenn NUR localhost im
// listen_addresses ist, lassen wir den bindaddress-Block weg und
// chrony bindet auf alle Interfaces (default), was für eine reine
// Client-Configuration nicht stört.
func filterNonLoopback(in []string) []string {
	out := []string{}
	for _, ip := range in {
		if ip == "::1" || ip == "localhost" || strings.HasPrefix(ip, "127.") {
			continue
		}
		out = append(out, ip)
	}
	return out
}