From afbfed5cb6d0d3868029ad2f80b3ec0cb22900b8 Mon Sep 17 00:00:00 2001
From: Samuel Lorch <sam@soontm.de>
Date: Mon, 24 Apr 2023 19:50:17 +0200
Subject: [PATCH] Add NTP Server Configuration

---
 internal/chrony/apply.go             | 37 ++++++++++++++++++++++++++++
 internal/chrony/config.go            | 17 +++++++++++++
 internal/chrony/template.go          | 26 +++++++++++++++++++
 internal/chrony/template/config.tmpl | 13 ++++++++++
 main.go                              |  2 ++
 5 files changed, 95 insertions(+)
 create mode 100644 internal/chrony/apply.go
 create mode 100644 internal/chrony/config.go
 create mode 100644 internal/chrony/template.go
 create mode 100644 internal/chrony/template/config.tmpl

diff --git a/internal/chrony/apply.go b/internal/chrony/apply.go
new file mode 100644
index 0000000..1690a64
--- /dev/null
+++ b/internal/chrony/apply.go
@@ -0,0 +1,37 @@
+package chrony
+
+import (
+	"context"
+	"fmt"
+
+	systemctl "github.com/coreos/go-systemd/v22/dbus"
+	"nfsense.net/nfsense/internal/definitions/config"
+	"nfsense.net/nfsense/internal/util"
+)
+
+const chronyConfigFile = "/etc/chrony.conf"
+
+func ApplyNTPConfiguration(currentConfig config.Config, pendingConfig config.Config) error {
+
+	conf, err := GenerateChronyConfiguration(pendingConfig)
+	if err != nil {
+		return fmt.Errorf("Generating Chrony Configuration: %w", err)
+	}
+
+	err = util.OverwriteFile(chronyConfigFile, conf)
+	if err != nil {
+		return fmt.Errorf("Writing Chrony Configuration: %w", err)
+	}
+
+	conn, err := systemctl.NewSystemConnectionContext(context.Background())
+	if err != nil {
+		return fmt.Errorf("Opening Dbus Connection: %w", err)
+	}
+
+	_, err = conn.ReloadOrRestartUnitContext(context.Background(), "chronyd.service", "replace", nil)
+	if err != nil {
+		return fmt.Errorf("restarting chronyd.service: %w", err)
+	}
+
+	return nil
+}
diff --git a/internal/chrony/config.go b/internal/chrony/config.go
new file mode 100644
index 0000000..cbde8e9
--- /dev/null
+++ b/internal/chrony/config.go
@@ -0,0 +1,17 @@
+package chrony
+
+import (
+	"bytes"
+	"fmt"
+
+	"nfsense.net/nfsense/internal/definitions/config"
+)
+
+func GenerateChronyConfiguration(conf config.Config) (string, error) {
+	buf := new(bytes.Buffer)
+	err := templates.ExecuteTemplate(buf, "config.tmpl", conf)
+	if err != nil {
+		return "", fmt.Errorf("executing server.tmpl template: %w", err)
+	}
+	return buf.String(), nil
+}
diff --git a/internal/chrony/template.go b/internal/chrony/template.go
new file mode 100644
index 0000000..9341652
--- /dev/null
+++ b/internal/chrony/template.go
@@ -0,0 +1,26 @@
+package chrony
+
+import (
+	"embed"
+	"text/template"
+
+	"nfsense.net/nfsense/internal/definitions/config"
+)
+
+//go:embed template
+var templateFS embed.FS
+var templates *template.Template
+
+func init() {
+	var err error
+	templates, err = template.New("").Funcs(template.FuncMap{
+		"getInterfaceNetworkAddressCIDR": getInterfaceNetworkAddressCIDR,
+	}).ParseFS(templateFS, "template/*.tmpl")
+	if err != nil {
+		panic(err)
+	}
+}
+
+func getInterfaceNetworkAddressCIDR(conf config.Config, name string) string {
+	return conf.Network.Interfaces[name].Address.Masked().String()
+}
diff --git a/internal/chrony/template/config.tmpl b/internal/chrony/template/config.tmpl
new file mode 100644
index 0000000..78fce09
--- /dev/null
+++ b/internal/chrony/template/config.tmpl
@@ -0,0 +1,13 @@
+pool pool.ntp.org iburst
+driftfile /var/lib/chrony/drift
+makestep 1.0 3
+rtcsync
+keyfile /etc/chrony.keys
+ntsdumpdir /var/lib/chrony
+leapsectz right/UTC
+logdir /var/log/chrony
+
+# Allowed Networks
+{{- range $i, $server := .Service.NTPServers }}
+allow {{ getInterfaceNetworkAddressCIDR $ $server.Interface }}
+{{- end }}
\ No newline at end of file
diff --git a/main.go b/main.go
index f4c190a..f591495 100644
--- a/main.go
+++ b/main.go
@@ -16,6 +16,7 @@ import (
 	"nfsense.net/nfsense/internal/api/network"
 	"nfsense.net/nfsense/internal/api/object"
 	"nfsense.net/nfsense/internal/api/service"
+	"nfsense.net/nfsense/internal/chrony"
 	"nfsense.net/nfsense/internal/config"
 	dhcp "nfsense.net/nfsense/internal/dhcp_server"
 	"nfsense.net/nfsense/internal/jsonrpc"
@@ -104,4 +105,5 @@ func RegisterAPIMethods(apiHandler *jsonrpc.Handler, configManager *config.Confi
 func RegisterApplyFunctions(configManager *config.ConfigManager) {
 	configManager.RegisterApplyFunction(networkd.ApplyNetworkdConfiguration)
 	configManager.RegisterApplyFunction(dhcp.ApplyDHCPServerConfiguration)
+	configManager.RegisterApplyFunction(chrony.ApplyNTPConfiguration)
 }