badguardhome/util/network_utils.go

187 lines
4.6 KiB
Go

package util
import (
"errors"
"fmt"
"net"
"os"
"runtime"
"strconv"
"syscall"
"time"
"github.com/AdguardTeam/golibs/log"
"github.com/joomcode/errorx"
)
// NetInterface represents a list of network interfaces
type NetInterface struct {
Name string // Network interface name
MTU int // MTU
HardwareAddr string // Hardware address
Addresses []string // Array with the network interface addresses
Subnets []string // Array with CIDR addresses of this network interface
Flags string // Network interface flags (up, broadcast, etc)
}
// 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 {
iface := ifaces[i]
netIfaces = append(netIfaces, iface)
}
return netIfaces, nil
}
// GetValidNetInterfacesForWeb 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()
}
// Collect network interface addresses
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())
netIface.Subnets = append(netIface.Subnets, ipNet.String())
}
// Discard interfaces with no addresses
if len(netIface.Addresses) != 0 {
netInterfaces = append(netInterfaces, netIface)
}
}
return netInterfaces, nil
}
// GetInterfaceByIP - 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 ""
}
// GetSubnet - Get IP address with netmask for the specified interface
// Returns an empty string if it fails to find it
func GetSubnet(ifaceName string) string {
netIfaces, err := GetValidNetInterfacesForWeb()
if err != nil {
log.Error("Could not get network interfaces info: %v", err)
return ""
}
for _, netIface := range netIfaces {
if netIface.Name == ifaceName && len(netIface.Subnets) > 0 {
return netIface.Subnets[0]
}
}
return ""
}
// CheckPortAvailable - check if TCP port is available
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
}
// CheckPacketPortAvailable - check if UDP port is available
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
}
// ErrorIsAddrInUse - 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
}