package main import ( "encoding/json" "errors" "fmt" "io/ioutil" "net" "net/http" "os/exec" "runtime" "strings" "time" "github.com/AdguardTeam/AdGuardHome/dhcpd" "github.com/AdguardTeam/golibs/file" "github.com/AdguardTeam/golibs/log" "github.com/joomcode/errorx" ) var dhcpServer = dhcpd.Server{} func handleDHCPStatus(w http.ResponseWriter, r *http.Request) { log.Tracef("%s %v", r.Method, r.URL) rawLeases := dhcpServer.Leases() leases := []map[string]string{} for i := range rawLeases { lease := map[string]string{ "mac": rawLeases[i].HWAddr.String(), "ip": rawLeases[i].IP.String(), "hostname": rawLeases[i].Hostname, "expires": rawLeases[i].Expiry.Format(time.RFC3339), } leases = append(leases, lease) } status := map[string]interface{}{ "config": config.DHCP, "leases": leases, } w.Header().Set("Content-Type", "application/json") err := json.NewEncoder(w).Encode(status) if err != nil { httpError(w, http.StatusInternalServerError, "Unable to marshal DHCP status json: %s", err) return } } func handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) { log.Tracef("%s %v", r.Method, r.URL) newconfig := dhcpd.ServerConfig{} err := json.NewDecoder(r.Body).Decode(&newconfig) if err != nil { httpError(w, http.StatusBadRequest, "Failed to parse new DHCP config json: %s", err) return } err = dhcpServer.Stop() if err != nil { log.Error("failed to stop the DHCP server: %s", err) } if newconfig.Enabled { 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 } } config.DHCP = newconfig httpUpdateConfigReloadDNSReturnOK(w, r) } func handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) { log.Tracef("%s %v", r.Method, r.URL) response := map[string]interface{}{} ifaces, err := getValidNetInterfaces() if err != nil { httpError(w, http.StatusInternalServerError, "Couldn't get interfaces: %s", err) return } for _, iface := range ifaces { if iface.Flags&net.FlagLoopback != 0 { // it's a loopback, skip it continue } if iface.Flags&net.FlagBroadcast == 0 { // this interface doesn't support broadcast, skip it continue } addrs, err := iface.Addrs() if err != nil { httpError(w, http.StatusInternalServerError, "Failed to get addresses for interface %s: %s", iface.Name, err) return } jsonIface := netInterface{ Name: iface.Name, MTU: iface.MTU, HardwareAddr: iface.HardwareAddr.String(), } if iface.Flags != 0 { jsonIface.Flags = iface.Flags.String() } // we don't want link-local addresses in json, so skip them for _, addr := range addrs { ipnet, ok := addr.(*net.IPNet) if !ok { // not an IPNet, should not happen httpError(w, http.StatusInternalServerError, "SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr) return } // ignore link-local if ipnet.IP.IsLinkLocalUnicast() { continue } jsonIface.Addresses = append(jsonIface.Addresses, ipnet.IP.String()) } if len(jsonIface.Addresses) != 0 { response[iface.Name] = jsonIface } } err = json.NewEncoder(w).Encode(response) if err != nil { httpError(w, http.StatusInternalServerError, "Failed to marshal json with available interfaces: %s", err) return } } // Perform the following tasks: // . Search for another DHCP server running // . Check if a static IP is configured for the network interface // Respond with results func handleDHCPFindActiveServer(w http.ResponseWriter, r *http.Request) { log.Tracef("%s %v", r.Method, r.URL) body, err := ioutil.ReadAll(r.Body) if err != nil { errorText := fmt.Sprintf("failed to read request body: %s", err) log.Error(errorText) http.Error(w, errorText, http.StatusBadRequest) return } interfaceName := strings.TrimSpace(string(body)) if interfaceName == "" { errorText := fmt.Sprintf("empty interface name specified") log.Error(errorText) http.Error(w, errorText, http.StatusBadRequest) return } found, err := dhcpd.CheckIfOtherDHCPServersPresent(interfaceName) othSrv := map[string]interface{}{} foundVal := "no" if found { foundVal = "yes" } else if err != nil { foundVal = "error" othSrv["error"] = err.Error() } othSrv["found"] = foundVal staticIP := map[string]interface{}{} isStaticIP, err := hasStaticIP(interfaceName) staticIPStatus := "yes" if err != nil { staticIPStatus = "error" staticIP["error"] = err.Error() } else if !isStaticIP { staticIPStatus = "no" staticIP["ip"] = getFullIP(interfaceName) } staticIP["static"] = staticIPStatus result := map[string]interface{}{} result["other_server"] = othSrv result["static_ip"] = staticIP w.Header().Set("Content-Type", "application/json") err = json.NewEncoder(w).Encode(result) if err != nil { httpError(w, http.StatusInternalServerError, "Failed to marshal DHCP found json: %s", err) return } } // Check if network interface has a static IP configured func hasStaticIP(ifaceName string) (bool, error) { if runtime.GOOS == "windows" { return false, errors.New("Can't detect static IP: not supported on Windows") } body, err := ioutil.ReadFile("/etc/dhcpcd.conf") if err != nil { return false, err } lines := strings.Split(string(body), "\n") nameLine := fmt.Sprintf("interface %s", ifaceName) withinInterfaceCtx := false for _, line := range lines { line = strings.TrimSpace(line) if withinInterfaceCtx && len(line) == 0 { // an empty line resets our state withinInterfaceCtx = false } if len(line) == 0 || line[0] == '#' { continue } line = strings.TrimSpace(line) if !withinInterfaceCtx { if line == nameLine { // we found our interface withinInterfaceCtx = true } } else { if strings.HasPrefix(line, "interface ") { // we found another interface - reset our state withinInterfaceCtx = false continue } if strings.HasPrefix(line, "static ip_address=") { return true, nil } } } return false, nil } // Get IP address with netmask func getFullIP(ifaceName string) string { cmd := exec.Command("ip", "-oneline", "-family", "inet", "address", "show", 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) < 4 { return "" } _, _, err = net.ParseCIDR(fields[3]) if err != nil { return "" } 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 return nil } err := dhcpServer.Start(&config.DHCP) if err != nil { return errorx.Decorate(err, "Couldn't start DHCP server") } return nil } func stopDHCPServer() error { if !config.DHCP.Enabled { return nil } if !dhcpServer.Enabled { return nil } err := dhcpServer.Stop() if err != nil { return errorx.Decorate(err, "Couldn't stop DHCP server") } return nil }