Pull request: create aghnet package

Merge in DNS/adguard-home from mk-aghnet to master

Updates #2829.

Squashed commit of the following:

commit 519806c04b8d0517aacce9c31f2d06ab56631937
Merge: 92376c86 97361234
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Mar 16 19:13:56 2021 +0300

    Merge branch 'master' into mk-aghnet

commit 92376c8665e529191aa482432f9d5e3e2e3afdc8
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Mar 16 18:37:22 2021 +0300

    aghnet: fix linux

commit 7f36d19b0e650d4e4fc5cf9ea4b501a7f636abeb
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Mar 16 18:08:30 2021 +0300

    aghnet: mv network utils from util

commit aa68c70c1146b8c32303c6e037953a41aa7d72f9
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Mar 16 17:30:06 2021 +0300

    aghnet: mv ipDetector here

commit b033657f5c5ee91f869c36508a5eb15976a174a0
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Mar 16 17:24:07 2021 +0300

    all: mk aghnet package, rename sysutil package

internal/aghnet/ipdetector.go

@@ -1,14 +1,14 @@
-package home
+package aghnet
 
 import "net"
 
-// ipDetector describes IP address properties.
+// IPDetector describes IP address properties.
-type ipDetector struct {
+type IPDetector struct {
 	nets []*net.IPNet
 }
 
-// newIPDetector returns a new IP detector.
+// NewIPDetector returns a new IP detector.
-func newIPDetector() (ipd *ipDetector, err error) {
+func NewIPDetector() (ipd *IPDetector, err error) {
 	specialNetworks := []string{
 		"0.0.0.0/8",
 		"10.0.0.0/8",
@@ -43,7 +43,7 @@ func newIPDetector() (ipd *ipDetector, err error) {
 		"fe80::/10",
 	}
 
-	ipd = &ipDetector{
+	ipd = &IPDetector{
 		nets: make([]*net.IPNet, len(specialNetworks)),
 	}
 	for i, ipnetStr := range specialNetworks {
@@ -59,10 +59,10 @@ func newIPDetector() (ipd *ipDetector, err error) {
 	return ipd, nil
 }
 
-// detectSpecialNetwork returns true if IP address is contained by any of
+// DetectSpecialNetwork returns true if IP address is contained by any of
 // special-purpose IP address registries according to RFC-6890
 // (https://tools.ietf.org/html/rfc6890).
-func (ipd *ipDetector) detectSpecialNetwork(ip net.IP) bool {
+func (ipd *IPDetector) DetectSpecialNetwork(ip net.IP) bool {
 	for _, ipnet := range ipd.nets {
 		if ipnet.Contains(ip) {
 			return true

internal/aghnet/ipdetector_test.go

@@ -1,4 +1,4 @@
-package home
+package aghnet
 
 import (
 	"net"
@@ -9,10 +9,10 @@ import (
 )
 
 func TestIPDetector_detectSpecialNetwork(t *testing.T) {
-	var ipd *ipDetector
+	var ipd *IPDetector
 	var err error
 
-	ipd, err = newIPDetector()
+	ipd, err = NewIPDetector()
 	require.Nil(t, err)
 
 	testCases := []struct {
@@ -139,7 +139,7 @@ func TestIPDetector_detectSpecialNetwork(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			assert.Equal(t, tc.want, ipd.detectSpecialNetwork(tc.ip))
+			assert.Equal(t, tc.want, ipd.DetectSpecialNetwork(tc.ip))
 		})
 	}
 }

internal/aghnet/net.go

@@ -1,4 +1,5 @@
-package util
+// Package aghnet contains some utilities for networking.
+package aghnet
 
 import (
 	"encoding/json"
@@ -6,14 +7,70 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"os/exec"
 	"runtime"
 	"strconv"
+	"strings"
 	"syscall"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
 	"github.com/AdguardTeam/golibs/log"
 )
 
+// ErrNoStaticIPInfo is returned by IfaceHasStaticIP when no information about
+// the IP being static is available.
+const ErrNoStaticIPInfo agherr.Error = "no information about static ip"
+
+// 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.
+func IfaceHasStaticIP(ifaceName string) (has bool, err error) {
+	return ifaceHasStaticIP(ifaceName)
+}
+
+// IfaceSetStaticIP sets static IP address for network interface.
+func IfaceSetStaticIP(ifaceName string) (err error) {
+	return ifaceSetStaticIP(ifaceName)
+}
+
+// GatewayIP returns IP address of interface's gateway.
+func GatewayIP(ifaceName string) net.IP {
+	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 nil
+	}
+
+	fields := strings.Fields(string(d))
+	// 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 || fields[0] != "default" {
+		return nil
+	}
+
+	return net.ParseIP(fields[2])
+}
+
+// CanBindPort checks if we can bind to the given port.
+func CanBindPort(port int) (can bool, err error) {
+	var addr *net.TCPAddr
+	addr, err = net.ResolveTCPAddr("tcp", fmt.Sprintf("127.0.0.1:%d", port))
+	if err != nil {
+		return false, err
+	}
+
+	var listener *net.TCPListener
+	listener, err = net.ListenTCP("tcp", addr)
+	if err != nil {
+		return false, err
+	}
+	_ = listener.Close()
+	return true, nil
+}
+
 // NetInterface represents an entry of network interfaces map.
 type NetInterface struct {
 	MTU          int              `json:"mtu"`

internal/aghnet/net_darwin.go

@@ -1,6 +1,6 @@
 // +build darwin
 
-package sysutil
+package aghnet
 
 import (
 	"errors"

internal/aghnet/net_linux.go

@@ -1,6 +1,6 @@
 // +build linux
 
-package sysutil
+package aghnet
 
 import (
 	"bufio"
@@ -13,7 +13,6 @@ import (
 	"strings"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghio"
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
 	"github.com/AdguardTeam/golibs/file"
 )
 
@@ -132,7 +131,7 @@ func ifacesStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
 }
 
 func ifaceSetStaticIP(ifaceName string) (err error) {
-	ipNet := util.GetSubnet(ifaceName)
+	ipNet := GetSubnet(ifaceName)
 	if ipNet.IP == nil {
 		return errors.New("can't get IP address")
 	}

internal/aghnet/net_linux_test.go

@@ -1,6 +1,6 @@
 // +build linux
 
-package sysutil
+package aghnet
 
 import (
 	"bytes"

internal/aghnet/net_others.go

@@ -1,6 +1,6 @@
 // +build !linux,!darwin
 
-package sysutil
+package aghnet
 
 import (
 	"fmt"

internal/aghnet/net_test.go

@@ -1,4 +1,4 @@
-package util
+package aghnet
 
 import (
 	"testing"

internal/aghos/os.go

@@ -1,5 +1,5 @@
-// Package sysutil contains utilities for functions requiring system calls.
+// Package aghos contains utilities for functions requiring system calls.
-package sysutil
+package aghos
 
 import "syscall"
 

internal/aghos/os_freebsd.go

@@ -1,6 +1,6 @@
 // +build freebsd
 
-package sysutil
+package aghos
 
 import (
 	"os"

internal/aghos/os_linux.go

@@ -1,6 +1,6 @@
 // +build linux
 
-package sysutil
+package aghos
 
 import (
 	"os"

internal/aghos/os_unix.go

@@ -1,6 +1,6 @@
 // +build aix darwin dragonfly netbsd openbsd solaris
 
-package sysutil
+package aghos
 
 import (
 	"os"

internal/aghos/os_windows.go

@@ -1,6 +1,6 @@
 // +build windows
 
-package sysutil
+package aghos
 
 import (
 	"fmt"

internal/aghos/syslog.go

@@ -1,4 +1,4 @@
-package sysutil
+package aghos
 
 // ConfigureSyslog reroutes standard logger output to syslog.
 func ConfigureSyslog(serviceName string) error {

internal/aghos/syslog_others.go

@@ -1,6 +1,6 @@
 // +build !windows,!plan9
 
-package sysutil
+package aghos
 
 import (
 	"log/syslog"

internal/aghos/syslog_windows.go

@@ -1,6 +1,6 @@
 // +build windows plan9
 
-package sysutil
+package aghos
 
 import (
 	"strings"

internal/aghos/sysutil_test.go

@@ -1,4 +1,4 @@
-package sysutil
+package aghos
 
 import (
 	"testing"

internal/dhcpd/http.go

@@ -10,8 +10,7 @@ import (
 	"os"
 	"strings"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/sysutil"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
 	"github.com/AdguardTeam/golibs/log"
 )
 
@@ -93,7 +92,7 @@ func (s *Server) handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
 
 func (s *Server) enableDHCP(ifaceName string) (code int, err error) {
 	var hasStaticIP bool
-	hasStaticIP, err = sysutil.IfaceHasStaticIP(ifaceName)
+	hasStaticIP, err = aghnet.IfaceHasStaticIP(ifaceName)
 	if err != nil {
 		if errors.Is(err, os.ErrPermission) {
 			// ErrPermission may happen here on Linux systems where
@@ -110,7 +109,7 @@ func (s *Server) enableDHCP(ifaceName string) (code int, err error) {
 			log.Info("error while checking static ip: %s; "+
 				"assuming machine has static ip and going on", err)
 			hasStaticIP = true
-		} else if errors.Is(err, sysutil.ErrNoStaticIPInfo) {
+		} else if errors.Is(err, aghnet.ErrNoStaticIPInfo) {
 			// Couldn't obtain a definitive answer.  Assume static
 			// IP an go on.
 			log.Info("can't check for static ip; " +
@@ -124,7 +123,7 @@ func (s *Server) enableDHCP(ifaceName string) (code int, err error) {
 	}
 
 	if !hasStaticIP {
-		err = sysutil.IfaceSetStaticIP(ifaceName)
+		err = aghnet.IfaceSetStaticIP(ifaceName)
 		if err != nil {
 			err = fmt.Errorf("setting static ip: %w", err)
 
@@ -267,7 +266,7 @@ type netInterfaceJSON struct {
 func (s *Server) handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
 	response := map[string]netInterfaceJSON{}
 
-	ifaces, err := util.GetValidNetInterfaces()
+	ifaces, err := aghnet.GetValidNetInterfaces()
 	if err != nil {
 		httpError(r, w, http.StatusInternalServerError, "Couldn't get interfaces: %s", err)
 		return
@@ -317,7 +316,7 @@ func (s *Server) handleDHCPInterfaces(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 		if len(jsonIface.Addrs4)+len(jsonIface.Addrs6) != 0 {
-			jsonIface.GatewayIP = sysutil.GatewayIP(iface.Name)
+			jsonIface.GatewayIP = aghnet.GatewayIP(iface.Name)
 			response[iface.Name] = jsonIface
 		}
 	}
@@ -397,13 +396,13 @@ func (s *Server) handleDHCPFindActiveServer(w http.ResponseWriter, r *http.Reque
 
 	found4, err4 := CheckIfOtherDHCPServersPresentV4(interfaceName)
 
-	isStaticIP, err := sysutil.IfaceHasStaticIP(interfaceName)
+	isStaticIP, err := aghnet.IfaceHasStaticIP(interfaceName)
 	if err != nil {
 		result.V4.StaticIP.Static = "error"
 		result.V4.StaticIP.Error = err.Error()
 	} else if !isStaticIP {
 		result.V4.StaticIP.Static = "no"
-		result.V4.StaticIP.IP = util.GetSubnet(interfaceName).String()
+		result.V4.StaticIP.IP = aghnet.GetSubnet(interfaceName).String()
 	}
 
 	if found4 {

internal/home/controlinstall.go

@@ -15,18 +15,16 @@ import (
 	"strings"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
-
-	"github.com/AdguardTeam/AdGuardHome/internal/sysutil"
 
 	"github.com/AdguardTeam/golibs/log"
 )
 
 // getAddrsResponse is the response for /install/get_addresses endpoint.
 type getAddrsResponse struct {
-	WebPort    int                           `json:"web_port"`
+	WebPort    int                             `json:"web_port"`
-	DNSPort    int                           `json:"dns_port"`
+	DNSPort    int                             `json:"dns_port"`
-	Interfaces map[string]*util.NetInterface `json:"interfaces"`
+	Interfaces map[string]*aghnet.NetInterface `json:"interfaces"`
 }
 
 // handleInstallGetAddresses is the handler for /install/get_addresses endpoint.
@@ -35,13 +33,13 @@ func (web *Web) handleInstallGetAddresses(w http.ResponseWriter, r *http.Request
 	data.WebPort = 80
 	data.DNSPort = 53
 
-	ifaces, err := util.GetValidNetInterfacesForWeb()
+	ifaces, err := aghnet.GetValidNetInterfacesForWeb()
 	if err != nil {
 		httpError(w, http.StatusInternalServerError, "Couldn't get interfaces: %s", err)
 		return
 	}
 
-	data.Interfaces = make(map[string]*util.NetInterface)
+	data.Interfaces = make(map[string]*aghnet.NetInterface)
 	for _, iface := range ifaces {
 		data.Interfaces[iface.Name] = iface
 	}
@@ -94,16 +92,16 @@ func (web *Web) handleInstallCheckConfig(w http.ResponseWriter, r *http.Request)
 	}
 
 	if reqData.Web.Port != 0 && reqData.Web.Port != config.BindPort && reqData.Web.Port != config.BetaBindPort {
-		err = util.CheckPortAvailable(reqData.Web.IP, reqData.Web.Port)
+		err = aghnet.CheckPortAvailable(reqData.Web.IP, reqData.Web.Port)
 		if err != nil {
 			respData.Web.Status = err.Error()
 		}
 	}
 
 	if reqData.DNS.Port != 0 {
-		err = util.CheckPacketPortAvailable(reqData.DNS.IP, reqData.DNS.Port)
+		err = aghnet.CheckPacketPortAvailable(reqData.DNS.IP, reqData.DNS.Port)
 
-		if util.ErrorIsAddrInUse(err) {
+		if aghnet.ErrorIsAddrInUse(err) {
 			canAutofix := checkDNSStubListener()
 			if canAutofix && reqData.DNS.Autofix {
 
@@ -112,7 +110,7 @@ func (web *Web) handleInstallCheckConfig(w http.ResponseWriter, r *http.Request)
 					log.Error("Couldn't disable DNSStubListener: %s", err)
 				}
 
-				err = util.CheckPacketPortAvailable(reqData.DNS.IP, reqData.DNS.Port)
+				err = aghnet.CheckPacketPortAvailable(reqData.DNS.IP, reqData.DNS.Port)
 				canAutofix = false
 			}
 
@@ -120,7 +118,7 @@ func (web *Web) handleInstallCheckConfig(w http.ResponseWriter, r *http.Request)
 		}
 
 		if err == nil {
-			err = util.CheckPortAvailable(reqData.DNS.IP, reqData.DNS.Port)
+			err = aghnet.CheckPortAvailable(reqData.DNS.IP, reqData.DNS.Port)
 		}
 
 		if err != nil {
@@ -144,7 +142,7 @@ func (web *Web) handleInstallCheckConfig(w http.ResponseWriter, r *http.Request)
 func handleStaticIP(ip net.IP, set bool) staticIPJSON {
 	resp := staticIPJSON{}
 
-	interfaceName := util.GetInterfaceByIP(ip)
+	interfaceName := aghnet.GetInterfaceByIP(ip)
 	resp.Static = "no"
 
 	if len(interfaceName) == 0 {
@@ -155,7 +153,7 @@ func handleStaticIP(ip net.IP, set bool) staticIPJSON {
 
 	if set {
 		// Try to set static IP for the specified interface
-		err := sysutil.IfaceSetStaticIP(interfaceName)
+		err := aghnet.IfaceSetStaticIP(interfaceName)
 		if err != nil {
 			resp.Static = "error"
 			resp.Error = err.Error()
@@ -165,7 +163,7 @@ func handleStaticIP(ip net.IP, set bool) staticIPJSON {
 
 	// Fallthrough here even if we set static IP
 	// Check if we have a static IP and return the details
-	isStaticIP, err := sysutil.IfaceHasStaticIP(interfaceName)
+	isStaticIP, err := aghnet.IfaceHasStaticIP(interfaceName)
 	if err != nil {
 		resp.Static = "error"
 		resp.Error = err.Error()
@@ -173,7 +171,7 @@ func handleStaticIP(ip net.IP, set bool) staticIPJSON {
 		if isStaticIP {
 			resp.Static = "yes"
 		}
-		resp.IP = util.GetSubnet(interfaceName).String()
+		resp.IP = aghnet.GetSubnet(interfaceName).String()
 	}
 	return resp
 }
@@ -315,7 +313,7 @@ func (web *Web) handleInstallConfigure(w http.ResponseWriter, r *http.Request) {
 
 	// validate that hosts and ports are bindable
 	if restartHTTP {
-		err = util.CheckPortAvailable(newSettings.Web.IP, newSettings.Web.Port)
+		err = aghnet.CheckPortAvailable(newSettings.Web.IP, newSettings.Web.Port)
 		if err != nil {
 			httpError(w, http.StatusBadRequest, "Impossible to listen on IP:port %s due to %s",
 				net.JoinHostPort(newSettings.Web.IP.String(), strconv.Itoa(newSettings.Web.Port)), err)
@@ -324,13 +322,13 @@ func (web *Web) handleInstallConfigure(w http.ResponseWriter, r *http.Request) {
 
 	}
 
-	err = util.CheckPacketPortAvailable(newSettings.DNS.IP, newSettings.DNS.Port)
+	err = aghnet.CheckPacketPortAvailable(newSettings.DNS.IP, newSettings.DNS.Port)
 	if err != nil {
 		httpError(w, http.StatusBadRequest, "%s", err)
 		return
 	}
 
-	err = util.CheckPortAvailable(newSettings.DNS.IP, newSettings.DNS.Port)
+	err = aghnet.CheckPortAvailable(newSettings.DNS.IP, newSettings.DNS.Port)
 	if err != nil {
 		httpError(w, http.StatusBadRequest, "%s", err)
 		return
@@ -537,9 +535,9 @@ func (web *Web) handleInstallConfigureBeta(w http.ResponseWriter, r *http.Reques
 // TODO(e.burkov): This should removed with the API v1 when the appropriate
 // functionality will appear in default firstRunData.
 type getAddrsResponseBeta struct {
-	WebPort    int                  `json:"web_port"`
+	WebPort    int                    `json:"web_port"`
-	DNSPort    int                  `json:"dns_port"`
+	DNSPort    int                    `json:"dns_port"`
-	Interfaces []*util.NetInterface `json:"interfaces"`
+	Interfaces []*aghnet.NetInterface `json:"interfaces"`
 }
 
 // handleInstallConfigureBeta is a substitution of /install/get_addresses
@@ -552,7 +550,7 @@ func (web *Web) handleInstallGetAddressesBeta(w http.ResponseWriter, r *http.Req
 	data.WebPort = 80
 	data.DNSPort = 53
 
-	ifaces, err := util.GetValidNetInterfacesForWeb()
+	ifaces, err := aghnet.GetValidNetInterfacesForWeb()
 	if err != nil {
 		httpError(w, http.StatusInternalServerError, "Couldn't get interfaces: %s", err)
 		return

internal/home/controlupdate.go

@@ -12,7 +12,7 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/sysutil"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghos"
 	"github.com/AdguardTeam/AdGuardHome/internal/updater"
 	"github.com/AdguardTeam/golibs/log"
 )
@@ -141,7 +141,7 @@ func (vr *versionResponse) confirmAutoUpdate() {
 				tlsConf.PortDNSOverQUIC < 1024)) ||
 				config.BindPort < 1024 ||
 				config.DNS.Port < 1024) {
-			canUpdate, _ = sysutil.CanBindPrivilegedPorts()
+			canUpdate, _ = aghos.CanBindPrivilegedPorts()
 		}
 		vr.CanAutoUpdate = &canUpdate
 	}

internal/home/dns.go

@@ -9,11 +9,11 @@ import (
 	"strconv"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
 	"github.com/AdguardTeam/AdGuardHome/internal/querylog"
 	"github.com/AdguardTeam/AdGuardHome/internal/stats"
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
 	"github.com/AdguardTeam/dnsproxy/proxy"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/ameshkov/dnscrypt/v2"
@@ -109,7 +109,7 @@ func onDNSRequest(d *proxy.DNSContext) {
 	if !ip.IsLoopback() {
 		Context.rdns.Begin(ip)
 	}
-	if !Context.ipDetector.detectSpecialNetwork(ip) {
+	if !Context.ipDetector.DetectSpecialNetwork(ip) {
 		Context.whois.Begin(ip)
 	}
 }
@@ -253,7 +253,7 @@ func getDNSAddresses() []string {
 	dnsAddresses := []string{}
 
 	if config.DNS.BindHost.IsUnspecified() {
-		ifaces, e := util.GetValidNetInterfacesForWeb()
+		ifaces, e := aghnet.GetValidNetInterfacesForWeb()
 		if e != nil {
 			log.Error("Couldn't get network interfaces: %v", e)
 			return []string{}
@@ -344,7 +344,7 @@ func startDNSServer() error {
 		if !ip.IsLoopback() {
 			Context.rdns.Begin(ip)
 		}
-		if !Context.ipDetector.detectSpecialNetwork(ip) {
+		if !Context.ipDetector.DetectSpecialNetwork(ip) {
 			Context.whois.Begin(ip)
 		}
 	}

internal/home/home.go

@@ -22,12 +22,13 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghos"
 	"github.com/AdguardTeam/AdGuardHome/internal/dhcpd"
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
 	"github.com/AdguardTeam/AdGuardHome/internal/querylog"
 	"github.com/AdguardTeam/AdGuardHome/internal/stats"
-	"github.com/AdguardTeam/AdGuardHome/internal/sysutil"
 	"github.com/AdguardTeam/AdGuardHome/internal/updater"
 	"github.com/AdguardTeam/AdGuardHome/internal/util"
 	"github.com/AdguardTeam/AdGuardHome/internal/version"
@@ -60,7 +61,7 @@ type homeContext struct {
 	autoHosts  util.AutoHosts       // IP-hostname pairs taken from system configuration (e.g. /etc/hosts) files
 	updater    *updater.Updater
 
-	ipDetector *ipDetector
+	ipDetector *aghnet.IPDetector
 
 	// mux is our custom http.ServeMux.
 	mux *http.ServeMux
@@ -204,7 +205,7 @@ func setupConfig(args options) {
 
 	if (runtime.GOOS == "linux" || runtime.GOOS == "darwin") &&
 		config.RlimitNoFile != 0 {
-		sysutil.SetRlimit(config.RlimitNoFile)
+		aghos.SetRlimit(config.RlimitNoFile)
 	}
 
 	// override bind host/port from the console
@@ -304,7 +305,7 @@ func run(args options) {
 		log.Fatalf("Can't initialize Web module")
 	}
 
-	Context.ipDetector, err = newIPDetector()
+	Context.ipDetector, err = aghnet.NewIPDetector()
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -361,7 +362,7 @@ func checkPermissions() {
 	if runtime.GOOS == "windows" {
 		// On Windows we need to have admin rights to run properly
 
-		admin, _ := sysutil.HaveAdminRights()
+		admin, _ := aghos.HaveAdminRights()
 		if admin {
 			return
 		}
@@ -370,7 +371,7 @@ func checkPermissions() {
 	}
 
 	// We should check if AdGuard Home is able to bind to port 53
-	ok, err := util.CanBindPort(53)
+	ok, err := aghnet.CanBindPort(53)
 
 	if ok {
 		log.Info("AdGuard Home can bind to port 53")
@@ -481,7 +482,7 @@ func configureLogger(args options) {
 
 	if ls.LogFile == configSyslog {
 		// Use syslog where it is possible and eventlog on Windows
-		err := sysutil.ConfigureSyslog(serviceName)
+		err := aghos.ConfigureSyslog(serviceName)
 		if err != nil {
 			log.Fatalf("cannot initialize syslog: %s", err)
 		}
@@ -592,7 +593,7 @@ func printHTTPAddresses(proto string) {
 		}
 	} else if config.BindHost.IsUnspecified() {
 		log.Println("AdGuard Home is available on the following addresses:")
-		ifaces, err := util.GetValidNetInterfacesForWeb()
+		ifaces, err := aghnet.GetValidNetInterfacesForWeb()
 		if err != nil {
 			// That's weird, but we'll ignore it
 			hostStr = config.BindHost.String()

internal/home/service.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"syscall"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/sysutil"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghos"
 	"github.com/AdguardTeam/AdGuardHome/internal/util"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/kardianos/service"
@@ -121,7 +121,7 @@ func sendSigReload() {
 		log.Error("Can't read PID file %s: %s", pidfile, err)
 		return
 	}
-	err = sysutil.SendProcessSignal(pid, syscall.SIGHUP)
+	err = aghos.SendProcessSignal(pid, syscall.SIGHUP)
 	if err != nil {
 		log.Error("Can't send signal to PID %d: %s", pid, err)
 		return

internal/home/web.go

@@ -9,7 +9,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/NYTimes/gziphandler"
 	"github.com/gobuffalo/packr"
@@ -117,7 +117,7 @@ func WebCheckPortAvailable(port int) bool {
 		alreadyRunning = true
 	}
 	if !alreadyRunning {
-		err := util.CheckPortAvailable(config.BindHost, port)
+		err := aghnet.CheckPortAvailable(config.BindHost, port)
 		if err != nil {
 			return false
 		}

internal/sysutil/net.go

@@ -1,46 +0,0 @@
-package sysutil
-
-import (
-	"net"
-	"os/exec"
-	"strings"
-
-	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
-	"github.com/AdguardTeam/golibs/log"
-)
-
-// ErrNoStaticIPInfo is returned by IfaceHasStaticIP when no information about
-// the IP being static is available.
-const ErrNoStaticIPInfo agherr.Error = "no information about static ip"
-
-// 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.
-func IfaceHasStaticIP(ifaceName string) (has bool, err error) {
-	return ifaceHasStaticIP(ifaceName)
-}
-
-// IfaceSetStaticIP sets static IP address for network interface.
-func IfaceSetStaticIP(ifaceName string) (err error) {
-	return ifaceSetStaticIP(ifaceName)
-}
-
-// GatewayIP returns IP address of interface's gateway.
-func GatewayIP(ifaceName string) net.IP {
-	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 nil
-	}
-
-	fields := strings.Fields(string(d))
-	// 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 || fields[0] != "default" {
-		return nil
-	}
-
-	return net.ParseIP(fields[2])
-}

internal/util/net.go

@@ -1,21 +0,0 @@
-package util
-
-import (
-	"fmt"
-	"net"
-)
-
-// CanBindPort - checks if we can bind to this port or not
-func CanBindPort(port int) (bool, error) {
-	addr, err := net.ResolveTCPAddr("tcp", fmt.Sprintf("127.0.0.1:%d", port))
-	if err != nil {
-		return false, err
-	}
-
-	l, err := net.ListenTCP("tcp", addr)
-	if err != nil {
-		return false, err
-	}
-	_ = l.Close()
-	return true, nil
-}