+ install: check static ip

* move code to network_utils

+ add tests

'dhcp' package has its own network_utils for now

+ doc: add static ip configuration algorithm on Ubuntu

AGHTechDoc.md

@@ -138,10 +138,13 @@ Request:
 	{
 	"web":{"port":80,"ip":"192.168.11.33"},
 	"dns":{"port":53,"ip":"127.0.0.1","autofix":false},
+	"set_static_ip": true | false
 	}
 
 Server should check whether a port is available only in case it itself isn't already listening on that port.
 
+If `set_static_ip` is `true`, Server attempts to set a static IP for the network interface chosen by `dns.ip` setting.  If the operation is successful, `static_ip.static` setting will be `yes`.  If it fails, `static_ip.static` setting will be set to `error` and `static_ip.error` will contain the error message.
+
 Server replies on success:
 
 	200 OK
@@ -149,7 +152,14 @@ Server replies on success:
 	{
 	"web":{"status":""},
 	"dns":{"status":""},
+	"static_ip": {
+		"static": "yes|no|error",
+		"ip": "<Current dynamic IP address>", // set if static=no
+		"error": "..." // set if static=error
 	}
+	}
+
+If `static_ip.static` is `no`, Server has detected that the system uses a dynamic address and it can  automatically set a static address if `set_static_ip` in request is `true`.  See section `Static IP check/set` for detailed process.
 
 Server replies on error:
 
@@ -172,7 +182,11 @@ Request:
 	POST /control/install/check_config
 
 	{
-	"dns":{"port":53,"ip":"127.0.0.1","autofix":false}
+	"dns":{
+		"port":53,
+		"ip":"127.0.0.1",
+		"autofix":false
+	}
 	}
 
 Check if DNSStubListener is enabled:
@@ -499,13 +513,7 @@ which will print:
 	default via 192.168.0.1 proto dhcp metric 100
 
 
-#### Phase 2
+#### Phase 2 (Raspbian)
-
-This method only works on Raspbian.
-
-On Ubuntu DHCP for a network interface can't be disabled via `dhcpcd.conf`.  This must be configured in `/etc/netplan/01-netcfg.yaml`.
-
-Fedora doesn't use `dhcpcd.conf` configuration at all.
 
 Step 1.
 
@@ -526,6 +534,44 @@ If we would set a different IP address, we'd need to replace the IP address for
 	ip addr replace dev eth0 192.168.0.1/24
 
 
+#### Phase 2 (Ubuntu)
+
+`/etc/netplan/01-netcfg.yaml` or `/etc/netplan/01-network-manager-all.yaml`
+
+This configuration example has a static IP set for `enp0s3` interface:
+
+	network:
+		version: 2
+		renderer: networkd
+		ethernets:
+			enp0s3:
+				dhcp4: no
+				addresses: [192.168.0.2/24]
+				gateway: 192.168.0.1
+				nameservers:
+					addresses: [192.168.0.1,8.8.8.8]
+
+For dynamic configuration `dhcp4: yes` is set.
+
+Make a backup copy to `/etc/netplan/01-netcfg.yaml.backup`.
+
+Apply:
+
+	netplan apply
+
+Restart network:
+
+	systemctl restart networking
+
+or:
+
+	systemctl restart network-manager
+
+or:
+
+	systemctl restart system-networkd
+
+
 ### Add a static lease
 
 Request:

dhcpd/dhcp_http.go

@@ -2,18 +2,14 @@ package dhcpd
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
-	"os/exec"
-	"runtime"
 	"strings"
 	"time"
 
-	"github.com/AdguardTeam/golibs/file"
 	"github.com/AdguardTeam/golibs/log"
 )
 
@@ -115,7 +111,7 @@ func (s *Server) handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-type netInterface struct {
+type netInterfaceJSON struct {
 	Name         string   `json:"name"`
 	MTU          int      `json:"mtu"`
 	HardwareAddr string   `json:"hardware_address"`
@@ -123,29 +119,6 @@ type netInterface struct {
 	Flags        string   `json:"flags"`
 }
 
-// getValidNetInterfaces returns interfaces that are eligible for DNS and/or DHCP
-// invalid interface is a ppp interface or the one that doesn't allow broadcasts
-func getValidNetInterfaces() ([]net.Interface, error) {
-	ifaces, err := net.Interfaces()
-	if err != nil {
-		return nil, fmt.Errorf("Couldn't get list of interfaces: %s", err)
-	}
-
-	netIfaces := []net.Interface{}
-
-	for i := range ifaces {
-		if ifaces[i].Flags&net.FlagPointToPoint != 0 {
-			// this interface is ppp, we're not interested in this one
-			continue
-		}
-
-		iface := ifaces[i]
-		netIfaces = append(netIfaces, iface)
-	}
-
-	return netIfaces, nil
-}
-
 func (s *Server) handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
 	response := map[string]interface{}{}
 
@@ -170,7 +143,7 @@ func (s *Server) handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		jsonIface := netInterface{
+		jsonIface := netInterfaceJSON{
 			Name:         iface.Name,
 			MTU:          iface.MTU,
 			HardwareAddr: iface.HardwareAddr.String(),
@@ -263,137 +236,6 @@ func (s *Server) handleDHCPFindActiveServer(w http.ResponseWriter, r *http.Reque
 	}
 }
 
-// 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 (s *Server) handleDHCPAddStaticLease(w http.ResponseWriter, r *http.Request) {
 
 	lj := staticLeaseJSON{}

dhcpd/network_utils.go

@@ -0,0 +1,317 @@
+package dhcpd
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"os/exec"
+	"runtime"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/AdguardTeam/golibs/file"
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/joomcode/errorx"
+)
+
+type netInterface struct {
+	Name         string
+	MTU          int
+	HardwareAddr string
+	Addresses    []string
+	Flags        string
+}
+
+// getValidNetInterfaces returns interfaces that are eligible for DNS and/or DHCP
+// invalid interface is a ppp interface or the one that doesn't allow broadcasts
+func getValidNetInterfaces() ([]net.Interface, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, fmt.Errorf("Couldn't get list of interfaces: %s", err)
+	}
+
+	netIfaces := []net.Interface{}
+
+	for i := range ifaces {
+		if ifaces[i].Flags&net.FlagPointToPoint != 0 {
+			// this interface is ppp, we're not interested in this one
+			continue
+		}
+
+		iface := ifaces[i]
+		netIfaces = append(netIfaces, iface)
+	}
+
+	return netIfaces, nil
+}
+
+// getValidNetInterfacesMap returns interfaces that are eligible for DNS and WEB only
+// we do not return link-local addresses here
+func getValidNetInterfacesForWeb() ([]netInterface, error) {
+	ifaces, err := getValidNetInterfaces()
+	if err != nil {
+		return nil, errorx.Decorate(err, "Couldn't get interfaces")
+	}
+	if len(ifaces) == 0 {
+		return nil, errors.New("couldn't find any legible interface")
+	}
+
+	var netInterfaces []netInterface
+
+	for _, iface := range ifaces {
+		addrs, e := iface.Addrs()
+		if e != nil {
+			return nil, errorx.Decorate(e, "Failed to get addresses for interface %s", iface.Name)
+		}
+
+		netIface := netInterface{
+			Name:         iface.Name,
+			MTU:          iface.MTU,
+			HardwareAddr: iface.HardwareAddr.String(),
+		}
+
+		if iface.Flags != 0 {
+			netIface.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
+				return nil, fmt.Errorf("got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr)
+			}
+			// ignore link-local
+			if ipnet.IP.IsLinkLocalUnicast() {
+				continue
+			}
+			netIface.Addresses = append(netIface.Addresses, ipnet.IP.String())
+		}
+		if len(netIface.Addresses) != 0 {
+			netInterfaces = append(netInterfaces, netIface)
+		}
+	}
+
+	return netInterfaces, nil
+}
+
+// Check if network interface has a static IP configured
+// Supports: Raspbian.
+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
+	}
+
+	return hasStaticIPDhcpcdConf(string(body), ifaceName), nil
+}
+
+// for dhcpcd.conf
+func hasStaticIPDhcpcdConf(data, ifaceName string) bool {
+	lines := strings.Split(data, "\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
+			}
+		}
+	}
+	return false
+}
+
+// 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 interface name by its IP address.
+func getInterfaceByIP(ip string) string {
+	ifaces, err := getValidNetInterfacesForWeb()
+	if err != nil {
+		return ""
+	}
+
+	for _, iface := range ifaces {
+		for _, addr := range iface.Addresses {
+			if ip == addr {
+				return iface.Name
+			}
+		}
+	}
+
+	return ""
+}
+
+// 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
+// Supports: Raspbian.
+func setStaticIP(ifaceName string) error {
+	ip := getFullIP(ifaceName)
+	if len(ip) == 0 {
+		return errors.New("Can't get IP address")
+	}
+
+	ip4, _, err := net.ParseCIDR(ip)
+	if err != nil {
+		return err
+	}
+	gatewayIP := getGatewayIP(ifaceName)
+	add := setStaticIPDhcpcdConf(ifaceName, ip, gatewayIP, ip4.String())
+
+	body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
+	if err != nil {
+		return err
+	}
+
+	body = append(body, []byte(add)...)
+	err = file.SafeWrite("/etc/dhcpcd.conf", body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// for dhcpcd.conf
+func setStaticIPDhcpcdConf(ifaceName, ip, gatewayIP, dnsIP string) string {
+	var body []byte
+
+	add := fmt.Sprintf("\ninterface %s\nstatic ip_address=%s\n",
+		ifaceName, ip)
+	body = append(body, []byte(add)...)
+
+	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",
+		dnsIP)
+	body = append(body, []byte(add)...)
+
+	return string(body)
+}
+
+// checkPortAvailable is not a cheap test to see if the port is bindable, because it's actually doing the bind momentarily
+func checkPortAvailable(host string, port int) error {
+	ln, err := net.Listen("tcp", net.JoinHostPort(host, strconv.Itoa(port)))
+	if err != nil {
+		return err
+	}
+	ln.Close()
+
+	// It seems that net.Listener.Close() doesn't close file descriptors right away.
+	// We wait for some time and hope that this fd will be closed.
+	time.Sleep(100 * time.Millisecond)
+	return nil
+}
+
+func checkPacketPortAvailable(host string, port int) error {
+	ln, err := net.ListenPacket("udp", net.JoinHostPort(host, strconv.Itoa(port)))
+	if err != nil {
+		return err
+	}
+	ln.Close()
+
+	// It seems that net.Listener.Close() doesn't close file descriptors right away.
+	// We wait for some time and hope that this fd will be closed.
+	time.Sleep(100 * time.Millisecond)
+	return err
+}
+
+// check if error is "address already in use"
+func errorIsAddrInUse(err error) bool {
+	errOpError, ok := err.(*net.OpError)
+	if !ok {
+		return false
+	}
+
+	errSyscallError, ok := errOpError.Err.(*os.SyscallError)
+	if !ok {
+		return false
+	}
+
+	errErrno, ok := errSyscallError.Err.(syscall.Errno)
+	if !ok {
+		return false
+	}
+
+	if runtime.GOOS == "windows" {
+		const WSAEADDRINUSE = 10048
+		return errErrno == WSAEADDRINUSE
+	}
+
+	return errErrno == syscall.EADDRINUSE
+}

home/control_install.go

@@ -22,6 +22,14 @@ type firstRunData struct {
 	Interfaces map[string]interface{} `json:"interfaces"`
 }
 
+type netInterfaceJSON struct {
+	Name         string   `json:"name"`
+	MTU          int      `json:"mtu"`
+	HardwareAddr string   `json:"hardware_address"`
+	Addresses    []string `json:"ip_addresses"`
+	Flags        string   `json:"flags"`
+}
+
 // Get initial installation settings
 func handleInstallGetAddresses(w http.ResponseWriter, r *http.Request) {
 	data := firstRunData{}
@@ -36,7 +44,14 @@ func handleInstallGetAddresses(w http.ResponseWriter, r *http.Request) {
 
 	data.Interfaces = make(map[string]interface{})
 	for _, iface := range ifaces {
-		data.Interfaces[iface.Name] = iface
+		ifaceJSON := netInterfaceJSON{
+			Name:         iface.Name,
+			MTU:          iface.MTU,
+			HardwareAddr: iface.HardwareAddr,
+			Addresses:    iface.Addresses,
+			Flags:        iface.Flags,
+		}
+		data.Interfaces[iface.Name] = ifaceJSON
 	}
 
 	w.Header().Set("Content-Type", "application/json")
@@ -51,6 +66,7 @@ type checkConfigReqEnt struct {
 	Port        int    `json:"port"`
 	IP          string `json:"ip"`
 	Autofix     bool   `json:"autofix"`
+	SetStaticIP bool   `json:"set_static_ip"`
 }
 type checkConfigReq struct {
 	Web checkConfigReqEnt `json:"web"`
@@ -61,9 +77,15 @@ type checkConfigRespEnt struct {
 	Status     string `json:"status"`
 	CanAutofix bool   `json:"can_autofix"`
 }
+type staticIPJSON struct {
+	Static string `json:"static"`
+	IP     string `json:"ip"`
+	Error  string `json:"error"`
+}
 type checkConfigResp struct {
 	Web      checkConfigRespEnt `json:"web"`
 	DNS      checkConfigRespEnt `json:"dns"`
+	StaticIP staticIPJSON       `json:"static_ip"`
 }
 
 // Check if ports are available, respond with results
@@ -108,6 +130,33 @@ func handleInstallCheckConfig(w http.ResponseWriter, r *http.Request) {
 
 		if err != nil {
 			respData.DNS.Status = fmt.Sprintf("%v", err)
+
+		} else {
+
+			interfaceName := getInterfaceByIP(reqData.DNS.IP)
+			staticIPStatus := "yes"
+
+			if len(interfaceName) == 0 {
+				staticIPStatus = "error"
+				respData.StaticIP.Error = fmt.Sprintf("Couldn't find network interface by IP %s", reqData.DNS.IP)
+
+			} else if reqData.DNS.SetStaticIP {
+				err = setStaticIP(interfaceName)
+				staticIPStatus = "error"
+				respData.StaticIP.Error = err.Error()
+
+			} else {
+				// check if we have a static IP
+				isStaticIP, err := hasStaticIP(interfaceName)
+				if err != nil {
+					staticIPStatus = "error"
+					respData.StaticIP.Error = err.Error()
+				} else if !isStaticIP {
+					staticIPStatus = "no"
+					respData.StaticIP.IP = getFullIP(interfaceName)
+				}
+			}
+			respData.StaticIP.Static = staticIPStatus
 		}
 	}
 

home/helpers.go

@@ -2,7 +2,6 @@ package home
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"net"
 	"net/http"
@@ -13,7 +12,6 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
-	"syscall"
 	"time"
 
 	"github.com/AdguardTeam/golibs/log"
@@ -151,117 +149,6 @@ func postInstallHandler(handler http.Handler) http.Handler {
 	return &postInstallHandlerStruct{handler}
 }
 
-// ------------------
-// network interfaces
-// ------------------
-type netInterface struct {
-	Name         string   `json:"name"`
-	MTU          int      `json:"mtu"`
-	HardwareAddr string   `json:"hardware_address"`
-	Addresses    []string `json:"ip_addresses"`
-	Flags        string   `json:"flags"`
-}
-
-// getValidNetInterfaces returns interfaces that are eligible for DNS and/or DHCP
-// invalid interface is a ppp interface or the one that doesn't allow broadcasts
-func getValidNetInterfaces() ([]net.Interface, error) {
-	ifaces, err := net.Interfaces()
-	if err != nil {
-		return nil, fmt.Errorf("Couldn't get list of interfaces: %s", err)
-	}
-
-	netIfaces := []net.Interface{}
-
-	for i := range ifaces {
-		if ifaces[i].Flags&net.FlagPointToPoint != 0 {
-			// this interface is ppp, we're not interested in this one
-			continue
-		}
-
-		iface := ifaces[i]
-		netIfaces = append(netIfaces, iface)
-	}
-
-	return netIfaces, nil
-}
-
-// getValidNetInterfacesMap returns interfaces that are eligible for DNS and WEB only
-// we do not return link-local addresses here
-func getValidNetInterfacesForWeb() ([]netInterface, error) {
-	ifaces, err := getValidNetInterfaces()
-	if err != nil {
-		return nil, errorx.Decorate(err, "Couldn't get interfaces")
-	}
-	if len(ifaces) == 0 {
-		return nil, errors.New("couldn't find any legible interface")
-	}
-
-	var netInterfaces []netInterface
-
-	for _, iface := range ifaces {
-		addrs, e := iface.Addrs()
-		if e != nil {
-			return nil, errorx.Decorate(e, "Failed to get addresses for interface %s", iface.Name)
-		}
-
-		netIface := netInterface{
-			Name:         iface.Name,
-			MTU:          iface.MTU,
-			HardwareAddr: iface.HardwareAddr.String(),
-		}
-
-		if iface.Flags != 0 {
-			netIface.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
-				return nil, fmt.Errorf("SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr)
-			}
-			// ignore link-local
-			if ipnet.IP.IsLinkLocalUnicast() {
-				continue
-			}
-			netIface.Addresses = append(netIface.Addresses, ipnet.IP.String())
-		}
-		if len(netIface.Addresses) != 0 {
-			netInterfaces = append(netInterfaces, netIface)
-		}
-	}
-
-	return netInterfaces, nil
-}
-
-// checkPortAvailable is not a cheap test to see if the port is bindable, because it's actually doing the bind momentarily
-func checkPortAvailable(host string, port int) error {
-	ln, err := net.Listen("tcp", net.JoinHostPort(host, strconv.Itoa(port)))
-	if err != nil {
-		return err
-	}
-	ln.Close()
-
-	// It seems that net.Listener.Close() doesn't close file descriptors right away.
-	// We wait for some time and hope that this fd will be closed.
-	time.Sleep(100 * time.Millisecond)
-	return nil
-}
-
-func checkPacketPortAvailable(host string, port int) error {
-	ln, err := net.ListenPacket("udp", net.JoinHostPort(host, strconv.Itoa(port)))
-	if err != nil {
-		return err
-	}
-	ln.Close()
-
-	// It seems that net.Listener.Close() doesn't close file descriptors right away.
-	// We wait for some time and hope that this fd will be closed.
-	time.Sleep(100 * time.Millisecond)
-	return err
-}
-
 // Connect to a remote server resolving hostname using our own DNS server
 func customDialContext(ctx context.Context, network, addr string) (net.Conn, error) {
 	log.Tracef("network:%v  addr:%v", network, addr)
@@ -303,31 +190,6 @@ func customDialContext(ctx context.Context, network, addr string) (net.Conn, err
 	return nil, errorx.DecorateMany(fmt.Sprintf("couldn't dial to %s", addr), dialErrs...)
 }
 
-// check if error is "address already in use"
-func errorIsAddrInUse(err error) bool {
-	errOpError, ok := err.(*net.OpError)
-	if !ok {
-		return false
-	}
-
-	errSyscallError, ok := errOpError.Err.(*os.SyscallError)
-	if !ok {
-		return false
-	}
-
-	errErrno, ok := errSyscallError.Err.(syscall.Errno)
-	if !ok {
-		return false
-	}
-
-	if runtime.GOOS == "windows" {
-		const WSAEADDRINUSE = 10048
-		return errErrno == WSAEADDRINUSE
-	}
-
-	return errErrno == syscall.EADDRINUSE
-}
-
 // ---------------------
 // debug logging helpers
 // ---------------------

home/network_utils.go

@@ -0,0 +1,317 @@
+package home
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"os/exec"
+	"runtime"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/AdguardTeam/golibs/file"
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/joomcode/errorx"
+)
+
+type netInterface struct {
+	Name         string
+	MTU          int
+	HardwareAddr string
+	Addresses    []string
+	Flags        string
+}
+
+// getValidNetInterfaces returns interfaces that are eligible for DNS and/or DHCP
+// invalid interface is a ppp interface or the one that doesn't allow broadcasts
+func getValidNetInterfaces() ([]net.Interface, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, fmt.Errorf("Couldn't get list of interfaces: %s", err)
+	}
+
+	netIfaces := []net.Interface{}
+
+	for i := range ifaces {
+		if ifaces[i].Flags&net.FlagPointToPoint != 0 {
+			// this interface is ppp, we're not interested in this one
+			continue
+		}
+
+		iface := ifaces[i]
+		netIfaces = append(netIfaces, iface)
+	}
+
+	return netIfaces, nil
+}
+
+// getValidNetInterfacesMap returns interfaces that are eligible for DNS and WEB only
+// we do not return link-local addresses here
+func getValidNetInterfacesForWeb() ([]netInterface, error) {
+	ifaces, err := getValidNetInterfaces()
+	if err != nil {
+		return nil, errorx.Decorate(err, "Couldn't get interfaces")
+	}
+	if len(ifaces) == 0 {
+		return nil, errors.New("couldn't find any legible interface")
+	}
+
+	var netInterfaces []netInterface
+
+	for _, iface := range ifaces {
+		addrs, e := iface.Addrs()
+		if e != nil {
+			return nil, errorx.Decorate(e, "Failed to get addresses for interface %s", iface.Name)
+		}
+
+		netIface := netInterface{
+			Name:         iface.Name,
+			MTU:          iface.MTU,
+			HardwareAddr: iface.HardwareAddr.String(),
+		}
+
+		if iface.Flags != 0 {
+			netIface.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
+				return nil, fmt.Errorf("got iface.Addrs() element %s that is not net.IPNet, it is %T", addr, addr)
+			}
+			// ignore link-local
+			if ipnet.IP.IsLinkLocalUnicast() {
+				continue
+			}
+			netIface.Addresses = append(netIface.Addresses, ipnet.IP.String())
+		}
+		if len(netIface.Addresses) != 0 {
+			netInterfaces = append(netInterfaces, netIface)
+		}
+	}
+
+	return netInterfaces, nil
+}
+
+// Check if network interface has a static IP configured
+// Supports: Raspbian.
+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
+	}
+
+	return hasStaticIPDhcpcdConf(string(body), ifaceName), nil
+}
+
+// for dhcpcd.conf
+func hasStaticIPDhcpcdConf(data, ifaceName string) bool {
+	lines := strings.Split(data, "\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
+			}
+		}
+	}
+	return false
+}
+
+// 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 interface name by its IP address.
+func getInterfaceByIP(ip string) string {
+	ifaces, err := getValidNetInterfacesForWeb()
+	if err != nil {
+		return ""
+	}
+
+	for _, iface := range ifaces {
+		for _, addr := range iface.Addresses {
+			if ip == addr {
+				return iface.Name
+			}
+		}
+	}
+
+	return ""
+}
+
+// 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
+// Supports: Raspbian.
+func setStaticIP(ifaceName string) error {
+	ip := getFullIP(ifaceName)
+	if len(ip) == 0 {
+		return errors.New("Can't get IP address")
+	}
+
+	ip4, _, err := net.ParseCIDR(ip)
+	if err != nil {
+		return err
+	}
+	gatewayIP := getGatewayIP(ifaceName)
+	add := setStaticIPDhcpcdConf(ifaceName, ip, gatewayIP, ip4.String())
+
+	body, err := ioutil.ReadFile("/etc/dhcpcd.conf")
+	if err != nil {
+		return err
+	}
+
+	body = append(body, []byte(add)...)
+	err = file.SafeWrite("/etc/dhcpcd.conf", body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// for dhcpcd.conf
+func setStaticIPDhcpcdConf(ifaceName, ip, gatewayIP, dnsIP string) string {
+	var body []byte
+
+	add := fmt.Sprintf("\ninterface %s\nstatic ip_address=%s\n",
+		ifaceName, ip)
+	body = append(body, []byte(add)...)
+
+	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",
+		dnsIP)
+	body = append(body, []byte(add)...)
+
+	return string(body)
+}
+
+// checkPortAvailable is not a cheap test to see if the port is bindable, because it's actually doing the bind momentarily
+func checkPortAvailable(host string, port int) error {
+	ln, err := net.Listen("tcp", net.JoinHostPort(host, strconv.Itoa(port)))
+	if err != nil {
+		return err
+	}
+	ln.Close()
+
+	// It seems that net.Listener.Close() doesn't close file descriptors right away.
+	// We wait for some time and hope that this fd will be closed.
+	time.Sleep(100 * time.Millisecond)
+	return nil
+}
+
+func checkPacketPortAvailable(host string, port int) error {
+	ln, err := net.ListenPacket("udp", net.JoinHostPort(host, strconv.Itoa(port)))
+	if err != nil {
+		return err
+	}
+	ln.Close()
+
+	// It seems that net.Listener.Close() doesn't close file descriptors right away.
+	// We wait for some time and hope that this fd will be closed.
+	time.Sleep(100 * time.Millisecond)
+	return err
+}
+
+// check if error is "address already in use"
+func errorIsAddrInUse(err error) bool {
+	errOpError, ok := err.(*net.OpError)
+	if !ok {
+		return false
+	}
+
+	errSyscallError, ok := errOpError.Err.(*os.SyscallError)
+	if !ok {
+		return false
+	}
+
+	errErrno, ok := errSyscallError.Err.(syscall.Errno)
+	if !ok {
+		return false
+	}
+
+	if runtime.GOOS == "windows" {
+		const WSAEADDRINUSE = 10048
+		return errErrno == WSAEADDRINUSE
+	}
+
+	return errErrno == syscall.EADDRINUSE
+}

home/network_utils_test.go

@@ -0,0 +1,61 @@
+package home
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHasStaticIPDhcpcdConf(t *testing.T) {
+	dhcpdConf := `#comment
+# comment
+
+interface eth0
+static ip_address=192.168.0.1/24
+
+# interface wlan0
+static ip_address=192.168.1.1/24
+
+# comment
+`
+	assert.True(t, !hasStaticIPDhcpcdConf(dhcpdConf, "wlan0"))
+
+	dhcpdConf = `#comment
+# comment
+
+interface eth0
+static ip_address=192.168.0.1/24
+
+# interface wlan0
+static ip_address=192.168.1.1/24
+
+# comment
+
+interface wlan0
+# comment
+static ip_address=192.168.2.1/24
+`
+	assert.True(t, hasStaticIPDhcpcdConf(dhcpdConf, "wlan0"))
+}
+
+func TestSetStaticIPDhcpcdConf(t *testing.T) {
+	dhcpcdConf := `
+interface wlan0
+static ip_address=192.168.0.2/24
+static routers=192.168.0.1
+static domain_name_servers=192.168.0.2
+
+`
+	s := setStaticIPDhcpcdConf("wlan0", "192.168.0.2/24", "192.168.0.1", "192.168.0.2")
+	assert.Equal(t, dhcpcdConf, s)
+
+	// without gateway
+	dhcpcdConf = `
+interface wlan0
+static ip_address=192.168.0.2/24
+static domain_name_servers=192.168.0.2
+
+`
+	s = setStaticIPDhcpcdConf("wlan0", "192.168.0.2/24", "", "192.168.0.2")
+	assert.Equal(t, dhcpcdConf, s)
+}