+ /control/dhcp/set_config: set static IP

dhcp.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/dhcpd"
+	"github.com/AdguardTeam/golibs/file"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/joomcode/errorx"
 )
@@ -61,7 +62,17 @@ func handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if newconfig.Enabled {
-		err := dhcpServer.Start(&newconfig)
+
+		staticIP, err := hasStaticIP(newconfig.InterfaceName)
+		if !staticIP && err == nil {
+			err = setStaticIP(newconfig.InterfaceName)
+			if err != nil {
+				httpError(w, http.StatusInternalServerError, "Failed to configure static IP: %s", err)
+				return
+			}
+		}
+
+		err = dhcpServer.Start(&newconfig)
 		if err != nil {
 			httpError(w, http.StatusBadRequest, "Failed to start DHCP server: %s", err)
 			return
@@ -258,6 +269,68 @@ func getFullIP(ifaceName string) string {
 	return fields[3]
 }
 
+// Get gateway IP address
+func getGatewayIP(ifaceName string) string {
+	cmd := exec.Command("ip", "route", "show", "dev", ifaceName)
+	log.Tracef("executing %s %v", cmd.Path, cmd.Args)
+	d, err := cmd.Output()
+	if err != nil || cmd.ProcessState.ExitCode() != 0 {
+		return ""
+	}
+
+	fields := strings.Fields(string(d))
+	if len(fields) < 3 || fields[0] != "default" {
+		return ""
+	}
+
+	ip := net.ParseIP(fields[2])
+	if ip == nil {
+		return ""
+	}
+
+	return fields[2]
+}
+
+// Set a static IP for network interface
+func setStaticIP(ifaceName string) error {
+	ip := getFullIP(ifaceName)
+	if len(ip) == 0 {
+		return errors.New("Can't get IP address")
+	}
+
+	body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
+	if err != nil {
+		return err
+	}
+
+	ip4, _, err := net.ParseCIDR(ip)
+	if err != nil {
+		return err
+	}
+
+	add := fmt.Sprintf("\ninterface %s\nstatic ip_address=%s\n",
+		ifaceName, ip)
+	body = append(body, []byte(add)...)
+
+	gatewayIP := getGatewayIP(ifaceName)
+	if len(gatewayIP) != 0 {
+		add = fmt.Sprintf("static routers=%s\n",
+			gatewayIP)
+		body = append(body, []byte(add)...)
+	}
+
+	add = fmt.Sprintf("static domain_name_servers=%s\n\n",
+		ip4)
+	body = append(body, []byte(add)...)
+
+	err = file.SafeWrite("/etc/dhcpcd.conf", body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func startDHCPServer() error {
 	if !config.DHCP.Enabled {
 		// not enabled, don't do anything