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add basic lla
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@EugeneOne1
EugeneOne1 committed Oct 12, 2022
1 parent f109fb1 commit 38305e5
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Showing 11 changed files with 198 additions and 150 deletions.
138 changes: 86 additions & 52 deletions internal/aghnet/net.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ import (
"fmt"
"io"
"net"
"net/netip"
"syscall"

"github.com/AdguardTeam/AdGuardHome/internal/aghos"
Expand All @@ -31,6 +32,12 @@ var (
// the IP being static is available.
const ErrNoStaticIPInfo errors.Error = "no information about static ip"

// IPv4Localhost returns 127.0.0.1, which returns true for [netip.Addr.Is4].
func IPv4Localhost() (ip netip.Addr) { return netip.AddrFrom4([4]byte{0: 127, 3: 1}) }

// IPv6Localhost returns ::1, which returns true for [netip.Addr.Is6].
func IPv6Localhost() (ip netip.Addr) { return netip.AddrFrom16([16]byte{15: 1}) }

// IfaceHasStaticIP checks if interface is configured to have static IP address.
// If it can't give a definitive answer, it returns false and an error for which
// errors.Is(err, ErrNoStaticIPInfo) is true.
Expand All @@ -47,26 +54,31 @@ func IfaceSetStaticIP(ifaceName string) (err error) {
//
// TODO(e.burkov): Investigate if the gateway address may be fetched in another
// way since not every machine has the software installed.
func GatewayIP(ifaceName string) (ip net.IP) {
func GatewayIP(ifaceName string) (ip netip.Addr) {
code, out, err := aghosRunCommand("ip", "route", "show", "dev", ifaceName)
if err != nil {
log.Debug("%s", err)

return nil
return ip
} else if code != 0 {
log.Debug("fetching gateway ip: unexpected exit code: %d", code)

return nil
return ip
}

fields := bytes.Fields(out)
// The meaningful "ip route" command output should contain the word
// "default" at first field and default gateway IP address at third field.
if len(fields) < 3 || string(fields[0]) != "default" {
return nil
return ip
}

return net.ParseIP(string(fields[2]))
ip, err = netip.ParseAddr(string(fields[2]))
if err != nil {
return netip.Addr{}
}

return ip
}

// CanBindPrivilegedPorts checks if current process can bind to privileged
Expand All @@ -78,9 +90,9 @@ func CanBindPrivilegedPorts() (can bool, err error) {
// NetInterface represents an entry of network interfaces map.
type NetInterface struct {
// Addresses are the network interface addresses.
Addresses []net.IP `json:"ip_addresses,omitempty"`
Addresses []netip.Addr `json:"ip_addresses,omitempty"`
// Subnets are the IP networks for this network interface.
Subnets []*net.IPNet `json:"-"`
Subnets []netip.Prefix `json:"-"`
Name string `json:"name"`
HardwareAddr net.HardwareAddr `json:"hardware_address"`
Flags net.Flags `json:"flags"`
Expand All @@ -101,57 +113,78 @@ func (iface NetInterface) MarshalJSON() ([]byte, error) {
})
}

func NetInterfaceFrom(iface *net.Interface) (niface *NetInterface, err error) {
niface = &NetInterface{
Name: iface.Name,
HardwareAddr: iface.HardwareAddr,
Flags: iface.Flags,
MTU: iface.MTU,
}

addrs, err := iface.Addrs()
if err != nil {
return nil, fmt.Errorf("failed to get addresses for interface %s: %w", iface.Name, err)
}

// Collect network interface addresses.
for _, addr := range addrs {
n, ok := addr.(*net.IPNet)
if !ok {
// Should be net.IPNet, this is weird.
return nil, fmt.Errorf("expected %[2]s to be %[1]T, got %[2]T", n, addr)
} else if ip4 := n.IP.To4(); ip4 != nil {
n.IP = ip4
}

ip, ok := netip.AddrFromSlice(n.IP)
if !ok {
return nil, fmt.Errorf("bad address %s", n.IP)
}

ip = ip.WithZone(iface.Name)

// Ignore link-local IPv4.
//
// TODO(e.burkov): !! or not??
if ip.Is4() && ip.IsLinkLocalUnicast() {
continue
}

ones, _ := n.Mask.Size()
p := netip.PrefixFrom(ip, ones)

niface.Addresses = append(niface.Addresses, ip)
niface.Subnets = append(niface.Subnets, p)
}

return niface, nil
}

// GetValidNetInterfacesForWeb returns interfaces that are eligible for DNS and
// WEB only we do not return link-local addresses here.
//
// TODO(e.burkov): Can't properly test the function since it's nontrivial to
// substitute net.Interface.Addrs and the net.InterfaceAddrs can't be used.
func GetValidNetInterfacesForWeb() (netIfaces []*NetInterface, err error) {
func GetValidNetInterfacesForWeb() (nifaces []*NetInterface, err error) {
ifaces, err := net.Interfaces()
if err != nil {
return nil, fmt.Errorf("couldn't get interfaces: %w", err)
return nil, fmt.Errorf("getting interfaces: %w", err)
} else if len(ifaces) == 0 {
return nil, errors.Error("couldn't find any legible interface")
return nil, errors.Error("no legible interfaces")
}

for _, iface := range ifaces {
var addrs []net.Addr
addrs, err = iface.Addrs()
for i := range ifaces {
var niface *NetInterface
niface, err = NetInterfaceFrom(&ifaces[i])
if err != nil {
return nil, fmt.Errorf("failed to get addresses for interface %s: %w", iface.Name, err)
}

netIface := &NetInterface{
MTU: iface.MTU,
Name: iface.Name,
HardwareAddr: iface.HardwareAddr,
Flags: iface.Flags,
}

// Collect network interface addresses.
for _, addr := range addrs {
ipNet, ok := addr.(*net.IPNet)
if !ok {
// Should be net.IPNet, this is weird.
return nil, fmt.Errorf("got %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)
netIface.Subnets = append(netIface.Subnets, ipNet)
}

// Discard interfaces with no addresses.
if len(netIface.Addresses) != 0 {
netIfaces = append(netIfaces, netIface)
return nil, err
} else if len(niface.Addresses) != 0 {
// Discard interfaces with no addresses.
nifaces = append(nifaces, niface)
}
}

return netIfaces, nil
return nifaces, nil
}

// InterfaceByIP returns the name of the interface bound to ip.
Expand All @@ -160,15 +193,15 @@ func GetValidNetInterfacesForWeb() (netIfaces []*NetInterface, err error) {
// IP address can be shared by multiple interfaces in some configurations.
//
// TODO(e.burkov): See TODO on GetValidNetInterfacesForWeb.
func InterfaceByIP(ip net.IP) (ifaceName string) {
func InterfaceByIP(ip netip.Addr) (ifaceName string) {
ifaces, err := GetValidNetInterfacesForWeb()
if err != nil {
return ""
}

for _, iface := range ifaces {
for _, addr := range iface.Addresses {
if ip.Equal(addr) {
if ip == addr {
return iface.Name
}
}
Expand All @@ -177,15 +210,16 @@ func InterfaceByIP(ip net.IP) (ifaceName string) {
return ""
}

// GetSubnet returns pointer to net.IPNet for the specified interface or nil if
// GetSubnet returns the subnet corresponding to the interface of zero prefix if
// the search fails.
//
// TODO(e.burkov): See TODO on GetValidNetInterfacesForWeb.
func GetSubnet(ifaceName string) *net.IPNet {
func GetSubnet(ifaceName string) (p netip.Prefix) {
netIfaces, err := GetValidNetInterfacesForWeb()
if err != nil {
log.Error("Could not get network interfaces info: %v", err)
return nil

return p
}

for _, netIface := range netIfaces {
Expand All @@ -194,14 +228,14 @@ func GetSubnet(ifaceName string) *net.IPNet {
}
}

return nil
return p
}

// CheckPort checks if the port is available for binding. network is expected
// to be one of "udp" and "tcp".
func CheckPort(network string, ip net.IP, port int) (err error) {
func CheckPort(network string, ipp netip.AddrPort) (err error) {
var c io.Closer
addr := netutil.IPPort{IP: ip, Port: port}.String()
addr := ipp.String()
switch network {
case "tcp":
c, err = net.Listen(network, addr)
Expand Down
14 changes: 7 additions & 7 deletions internal/aghnet/net_linux.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ import (
"bufio"
"fmt"
"io"
"net"
"net/netip"
"os"
"strings"

Expand Down Expand Up @@ -151,7 +151,7 @@ func findIfaceLine(s *bufio.Scanner, name string) (ok bool) {
// interface through dhcpcd.conf.
func ifaceSetStaticIP(ifaceName string) (err error) {
ipNet := GetSubnet(ifaceName)
if ipNet.IP == nil {
if !ipNet.Addr().IsValid() {
return errors.Error("can't get IP address")
}

Expand All @@ -174,7 +174,7 @@ func ifaceSetStaticIP(ifaceName string) (err error) {

// dhcpcdConfIface returns configuration lines for the dhcpdc.conf files that
// configure the interface to have a static IP.
func dhcpcdConfIface(ifaceName string, ipNet *net.IPNet, gwIP net.IP) (conf string) {
func dhcpcdConfIface(ifaceName string, subnet netip.Prefix, gateway netip.Addr) (conf string) {
b := &strings.Builder{}
stringutil.WriteToBuilder(
b,
Expand All @@ -183,15 +183,15 @@ func dhcpcdConfIface(ifaceName string, ipNet *net.IPNet, gwIP net.IP) (conf stri
" added by AdGuard Home.\ninterface ",
ifaceName,
"\nstatic ip_address=",
ipNet.String(),
subnet.String(),
"\n",
)

if gwIP != nil {
stringutil.WriteToBuilder(b, "static routers=", gwIP.String(), "\n")
if gateway.IsValid() {
stringutil.WriteToBuilder(b, "static routers=", gateway.String(), "\n")
}

stringutil.WriteToBuilder(b, "static domain_name_servers=", ipNet.IP.String(), "\n\n")
stringutil.WriteToBuilder(b, "static domain_name_servers=", subnet.Addr().String(), "\n\n")

return b.String()
}
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