f-33: mise en place d'un nouveau system de reservation #33

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/dhcp/reservation.go

@@ -0,0 +1,69 @@
+package dhcp
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type Reservation struct {
+	MAC string
+	IP  string
+}
+
+func HostsDir(confDir, name string) string {
+	return filepath.Join(confDir, name+".hosts.d")
+}
+
+func OptsDir(confDir, name string) string {
+	return filepath.Join(confDir, name+".opts.d")
+}
+
+func UnitName(name string) string {
+	return "dnsmasq@" + name + ".service"
+}
+
+func WriteReservations(confDir, name, vmName string, res []Reservation) error {
+	if len(res) == 0 {
+		return fmt.Errorf("no reservation for vm %q: it would get no address", vmName)
+	}
+
+	dir := HostsDir(confDir, name)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return fmt.Errorf("create %s: %w", dir, err)
+	}
+
+	var sb strings.Builder
+	for _, r := range res {
+		if r.MAC == "" || r.IP == "" {
+			return fmt.Errorf("incomplete reservation for vm %q: mac=%q ip=%q", vmName, r.MAC, r.IP)
+		}
+		fmt.Fprintf(&sb, "%s,%s\n", r.MAC, r.IP)
+	}
+
+	path := filepath.Join(dir, vmName)
+	if err := os.WriteFile(path, []byte(sb.String()), 0644); err != nil {
+		return fmt.Errorf("write %s: %w", path, err)
+	}
+	return nil
+}
+
+func RemoveReservations(confDir, name, vmName string) error {
+	for _, dir := range []string{HostsDir(confDir, name), OptsDir(confDir, name)} {
+		path := filepath.Join(dir, vmName)
+		if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
+			return fmt.Errorf("remove %s: %w", path, err)
+		}
+	}
+	return nil
+}
+
+func RemoveSubnetDirs(confDir, name string) error {
+	for _, dir := range []string{HostsDir(confDir, name), OptsDir(confDir, name)} {
+		if err := os.RemoveAll(dir); err != nil {
+			return fmt.Errorf("remove %s: %w", dir, err)
+		}
+	}
+	return nil
+}