+ Replace dnsmasq on OpenWRT (minimal configuration)

AGHTechDoc.md

@@ -64,6 +64,7 @@ Contents:
 	* API: Log in
 	* API: Log out
 	* API: Get current user info
+* Replace dnsmasq on OpenWRT
 
 
 ## Relations between subsystems
@@ -1594,3 +1595,66 @@ Response:
 	}
 
 If no client is configured then authentication is disabled and server sends an empty response.
+
+
+## Replace dnsmasq on OpenWRT
+
+`/etc/init.d/dnsmasq` script creates a dnsmasq.conf file and then starts dnsmasq.
+To replace dnsmasq we have to read system configuration files and update (create new, if necessary) our .yaml file accordingly.
+
+If started as:
+
+	./AdGuardHome --auto-config
+
+* Read `/etc/config/network`:
+
+		config interface 'lan'
+			option netmask '255.255.255.0'
+			option ipaddr '192.168.8.1'
+
+* Read `/etc/config/dhcp`:
+
+		config dhcp 'lan'
+			option start '100'
+			option limit '150'
+			option leasetime '12h'
+
+* Write this yaml configuration:
+
+		dhcp:
+			enabled: true
+			interface_name: "br-lan"
+			gateway_ip: "192.168.8.1"
+			subnet_mask: "255.255.255.0"
+			range_start: "192.168.8.100"
+			range_end: "192.168.8.249"
+			lease_duration: 86400
+			icmp_timeout_msec: 1000
+
+* Read `/etc/config/dhcp`:
+
+		config host '123412341234'
+			option mac '12:34:12:34:12:34'
+			option ip '192.168.8.2'
+			option name 'hostname'
+
+* Add a static lease to leases.db:
+
+		12:34:12:34:12:34 | 192.168.8.2 | hostname
+
+* Read `/etc/resolv.conf`:
+
+		nameserver <IP1>
+		nameserver <IP2>
+
+* Write this yaml configuration:
+
+		dns:
+			bootstrap_dns:
+			- IP1
+			- IP2
+
+And service script starts AGH like this:
+
+	.../AdGuardHome --auto-config
+	.../AdGuardHome

dhcpd/dhcpd.go

@@ -139,6 +139,11 @@ func (s *Server) Init(config ServerConfig) error {
 	return nil
 }
 
+// Save - save leases in DB
+func (s *Server) Save() {
+	s.dbStore()
+}
+
 // SetOnLeaseChanged - set callback
 func (s *Server) SetOnLeaseChanged(onLeaseChanged onLeaseChangedT) {
 	s.onLeaseChanged = onLeaseChanged
@@ -608,6 +613,11 @@ func (s *Server) handleDecline(p dhcp4.Packet, options dhcp4.Options) dhcp4.Pack
 
 // AddStaticLease adds a static lease (thread-safe)
 func (s *Server) AddStaticLease(l Lease) error {
+	return s.AddStaticLeaseWithFlags(l, true)
+}
+
+// AddStaticLeaseWithFlags - add a static lease (thread-safe)
+func (s *Server) AddStaticLeaseWithFlags(l Lease, flush bool) error {
 	if len(l.IP) != 4 {
 		return fmt.Errorf("Invalid IP")
 	}
@@ -627,7 +637,9 @@ func (s *Server) AddStaticLease(l Lease) error {
 	}
 	s.leases = append(s.leases, &l)
 	s.reserveIP(l.IP, l.HWAddr)
-	s.dbStore()
+	if flush {
+		s.dbStore()
+	}
 	s.leasesLock.Unlock()
 	s.notify(LeaseChangedAddedStatic)
 	return nil

home/home.go

@@ -138,12 +138,9 @@ func Main(version string, channel string, armVer string) {
 // run is a blocking method!
 // nolint
 func run(args options) {
-	// config file path can be overridden by command-line arguments:
+	Context.configFilename = "AdGuardHome.yaml"
 	if args.configFilename != "" {
 		Context.configFilename = args.configFilename
-	} else {
-		// Default config file name
-		Context.configFilename = "AdGuardHome.yaml"
 	}
 
 	// configure working dir and config path
@@ -459,6 +456,7 @@ type options struct {
 	pidFile        string // File name to save PID to
 	checkConfig    bool   // Check configuration and exit
 	disableUpdate  bool   // If set, don't check for updates
+	hasAutoConfig  bool   // 'auto-config' argument is specified
 
 	// service control action (see service.ControlAction array + "status" command)
 	serviceControlAction string
@@ -498,6 +496,9 @@ func loadOptions() options {
 		{"pidfile", "", "Path to a file where PID is stored", func(value string) { o.pidFile = value }, nil},
 		{"check-config", "", "Check configuration and exit", nil, func() { o.checkConfig = true }},
 		{"no-check-update", "", "Don't check for updates", nil, func() { o.disableUpdate = true }},
+		{"auto-config", "", "Create or update YAML configuration file from OpenWRT system configuration", nil, func() {
+			o.hasAutoConfig = true
+		}},
 		{"verbose", "v", "Enable verbose output", nil, func() { o.verbose = true }},
 		{"version", "", "Show the version and exit", nil, func() {
 			fmt.Printf("AdGuardHome %s\n", versionString)
@@ -550,6 +551,18 @@ func loadOptions() options {
 		}
 	}
 
+	if o.verbose {
+		log.SetLevel(log.DEBUG)
+	}
+
+	if o.hasAutoConfig {
+		err := autoConfig(o.configFilename)
+		if err != nil {
+			log.Fatalf("%s", err)
+		}
+		os.Exit(0)
+	}
+
 	return o
 }
 

home/openwrt.go

@@ -0,0 +1,344 @@
+package home
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strconv"
+	"strings"
+
+	"github.com/AdguardTeam/AdGuardHome/dhcpd"
+	"github.com/AdguardTeam/AdGuardHome/util"
+	"github.com/AdguardTeam/golibs/log"
+)
+
+type openwrtConfig struct {
+	// network:
+	netmask string
+	ipaddr  string
+
+	// dhcp:
+	dhcpStart     string
+	dhcpLimit     string
+	dhcpLeasetime string
+
+	// dhcp static leases:
+	leases []dhcpd.Lease
+
+	// resolv.conf:
+	nameservers []string
+
+	// yaml.dhcp:
+	iface      string
+	gwIP       string
+	snMask     string
+	rangeStart string
+	rangeEnd   string
+	leaseDur   uint32
+
+	// yaml.dns.bootstrap_dns:
+	bsDNS []string
+}
+
+// Parse command line: "option name 'value'"
+func parseCmd(line string) (string, string, string) {
+	word1 := util.SplitNext(&line, ' ')
+	word2 := util.SplitNext(&line, ' ')
+	word3 := util.SplitNext(&line, ' ')
+	if len(word3) > 2 && word3[0] == '\'' && word3[len(word3)-1] == '\'' {
+		// 'value' -> value
+		word3 = word3[1:]
+		word3 = word3[:len(word3)-1]
+	}
+	return word1, word2, word3
+}
+
+// Parse system configuration data
+// nolint(gocyclo)
+func (oc *openwrtConfig) readConf(data []byte, section string, iface string) {
+	state := 0
+	sr := strings.NewReader(string(data))
+	r := bufio.NewReader(sr)
+	for {
+		line, err := r.ReadString('\n')
+		line = strings.TrimSpace(line)
+		if len(line) == 0 {
+			if state == 2 {
+				return
+			}
+			state = 0
+		}
+
+		word1, word2, word3 := parseCmd(line)
+
+		switch state {
+		case 0:
+			if word1 == "config" {
+				state = 1
+				if word2 == section && word3 == iface {
+					// found the needed section
+					if word2 == "interface" {
+						state = 2 // found the needed interface
+					} else if word2 == "dhcp" {
+						state = 3
+					}
+				}
+			}
+
+		case 1:
+			// not interested
+			break
+
+		case 2:
+			if word1 != "option" {
+				break
+			}
+			switch word2 {
+			case "netmask":
+				oc.netmask = word3
+			case "ipaddr":
+				oc.ipaddr = word3
+			}
+
+		case 3:
+			if word1 != "option" {
+				break
+			}
+			switch word2 {
+			case "start":
+				oc.dhcpStart = word3
+			case "limit":
+				oc.dhcpLimit = word3
+			case "leasetime":
+				oc.dhcpLeasetime = word3
+			}
+		}
+
+		if err != nil {
+			break
+		}
+	}
+}
+func (oc *openwrtConfig) readConfDHCPStatic(data []byte) error {
+	state := 0
+	sr := strings.NewReader(string(data))
+	r := bufio.NewReader(sr)
+	lease := dhcpd.Lease{}
+	for {
+		line, err := r.ReadString('\n')
+		line = strings.TrimSpace(line)
+		if len(line) == 0 {
+			if len(lease.HWAddr) != 0 && len(lease.IP) != 0 {
+				oc.leases = append(oc.leases, lease)
+			}
+			lease = dhcpd.Lease{}
+			state = 0
+		}
+
+		word1, word2, word3 := parseCmd(line)
+
+		switch state {
+		case 0:
+			if word1 == "config" {
+				state = 1
+				if word2 == "host" {
+					state = 2
+				}
+			}
+
+		case 1:
+			// not interested
+			break
+
+		case 2:
+			if word1 != "option" {
+				break
+			}
+			switch word2 {
+			case "mac":
+				lease.HWAddr, err = net.ParseMAC(word3)
+				if err != nil {
+					return err
+				}
+
+			case "ip":
+				lease.IP = net.ParseIP(word3)
+				if lease.IP == nil || lease.IP.To4() == nil {
+					return fmt.Errorf("Invalid IP address")
+				}
+
+			case "name":
+				lease.Hostname = word3
+			}
+		}
+
+		if err != nil {
+			break
+		}
+	}
+
+	if len(lease.HWAddr) != 0 && len(lease.IP) != 0 {
+		oc.leases = append(oc.leases, lease)
+	}
+	return nil
+}
+
+// Parse "/etc/resolv.conf" data
+func (oc *openwrtConfig) readResolvConf(data []byte) {
+	lines := string(data)
+
+	for len(lines) != 0 {
+		line := util.SplitNext(&lines, '\n')
+		key := util.SplitNext(&line, ' ')
+		if key == "nameserver" {
+			val := util.SplitNext(&line, ' ')
+			oc.nameservers = append(oc.nameservers, val)
+		}
+	}
+}
+
+// Convert system config parameters to the format suitable by our yaml config
+func (oc *openwrtConfig) prepareOutput() error {
+	oc.iface = "br-lan"
+
+	ipAddr := net.ParseIP(oc.ipaddr)
+	if ipAddr == nil || ipAddr.To4() == nil {
+		return fmt.Errorf("Invalid IP: %s", oc.ipaddr)
+	}
+	oc.gwIP = oc.ipaddr
+
+	ip := net.ParseIP(oc.netmask)
+	if ip == nil || ip.To4() == nil {
+		return fmt.Errorf("Invalid IP: %s", oc.netmask)
+	}
+	oc.snMask = oc.netmask
+
+	nStart, err := strconv.Atoi(oc.dhcpStart)
+	if err != nil {
+		return fmt.Errorf("Invalid 'start': %s", oc.dhcpStart)
+	}
+	rangeStart := make(net.IP, 4)
+	copy(rangeStart, ipAddr.To4())
+	rangeStart[3] = byte(nStart)
+	oc.rangeStart = rangeStart.String()
+
+	nLim, err := strconv.Atoi(oc.dhcpLimit)
+	if err != nil {
+		return fmt.Errorf("Invalid 'start': %s", oc.dhcpLimit)
+	}
+	n := nStart + nLim - 1
+	if n <= 0 || n > 255 {
+		return fmt.Errorf("Invalid 'start' or 'limit': %s/%s", oc.dhcpStart, oc.dhcpLimit)
+	}
+	rangeEnd := make(net.IP, 4)
+	copy(rangeEnd, ipAddr.To4())
+	rangeEnd[3] = byte(n)
+	oc.rangeEnd = rangeEnd.String()
+
+	if len(oc.dhcpLeasetime) == 0 || oc.dhcpLeasetime[len(oc.dhcpLeasetime)-1] != 'h' {
+		return fmt.Errorf("Invalid leasetime: %s", oc.dhcpLeasetime)
+	}
+	n, err = strconv.Atoi(oc.dhcpLeasetime[:len(oc.dhcpLeasetime)-1])
+	if err != nil {
+		return fmt.Errorf("Invalid leasetime: %s", oc.dhcpLeasetime)
+	}
+	oc.leaseDur = uint32(n) * 60 * 60
+
+	for _, s := range oc.nameservers {
+		if net.ParseIP(s) == nil {
+			continue
+		}
+		oc.bsDNS = append(oc.bsDNS, s)
+	}
+	return nil
+}
+
+func (oc *openwrtConfig) Start() error {
+	data, err := ioutil.ReadFile("/etc/config/network")
+	if err != nil {
+		return err
+	}
+	oc.readConf(data, "interface", "lan")
+
+	data, err = ioutil.ReadFile("/etc/config/dhcp")
+	if err != nil {
+		return err
+	}
+	oc.readConf(data, "dhcp", "lan")
+
+	err = oc.prepareOutput()
+	if err != nil {
+		return err
+	}
+
+	oc.readConfDHCPStatic(data)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Read system configuration files and write our configuration files
+func autoConfig(configFn string) error {
+	oc := openwrtConfig{}
+	err := oc.Start()
+	if err != nil {
+		return err
+	}
+
+	// config file path can be overridden by command-line arguments:
+	Context.configFilename = "AdGuardHome.yaml"
+	if len(configFn) != 0 {
+		Context.configFilename = configFn
+	}
+
+	initConfig()
+	if util.FileExists(config.getConfigFilename()) {
+		err = upgradeConfig()
+		if err != nil {
+			return err
+		}
+		err = parseConfig()
+		if err != nil {
+			return err
+		}
+	}
+
+	config.DNS.BootstrapDNS = oc.bsDNS
+
+	config.DHCP.Enabled = true
+	config.DHCP.InterfaceName = oc.iface
+	config.DHCP.GatewayIP = oc.gwIP
+	config.DHCP.SubnetMask = oc.snMask
+	config.DHCP.RangeStart = oc.rangeStart
+	config.DHCP.RangeEnd = oc.rangeEnd
+	config.DHCP.LeaseDuration = oc.leaseDur
+
+	err = config.write()
+	if err != nil {
+		return err
+	}
+
+	dconf := dhcpd.ServerConfig{
+		WorkDir: Context.workDir,
+	}
+	ds := dhcpd.Create(dconf)
+	if ds == nil {
+		return fmt.Errorf("can't initialize DHCP module")
+	}
+	for _, ocl := range oc.leases {
+		l := dhcpd.Lease{
+			HWAddr:   ocl.HWAddr,
+			IP:       ocl.IP.To4(),
+			Hostname: ocl.Hostname,
+		}
+		ds.AddStaticLeaseWithFlags(l, false)
+		log.Debug("Static DHCP lease: %s -> %s (%s)",
+			l.HWAddr, l.IP, l.Hostname)
+	}
+	ds.Save()
+
+	return nil
+}

home/openwrt_test.go

@@ -0,0 +1,60 @@
+package home
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReadConf(t *testing.T) {
+	oc := openwrtConfig{}
+	data := []byte(`		config interface 'lan'
+option netmask '255.255.255.0'
+option ipaddr '192.168.8.1'`)
+	oc.readConf(data, "interface", "lan")
+	assert.Equal(t, "255.255.255.0", oc.netmask)
+	assert.Equal(t, "192.168.8.1", oc.ipaddr)
+
+	data = []byte(`		config dhcp 'unknown'
+
+config dhcp 'lan'
+option start '100'
+option limit '150'
+option leasetime '12h'
+
+config dhcp 'unknown'`)
+	oc.readConf(data, "dhcp", "lan")
+	assert.Equal(t, "100", oc.dhcpStart)
+	assert.Equal(t, "150", oc.dhcpLimit)
+	assert.Equal(t, "12h", oc.dhcpLeasetime)
+
+	data = []byte(`		# comment
+nameserver abab::1234
+
+nameserver 1.2.3.4`)
+	oc.readResolvConf(data)
+	assert.Equal(t, "abab::1234", oc.nameservers[0])
+	assert.Equal(t, "1.2.3.4", oc.nameservers[1])
+
+	err := oc.prepareOutput()
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "br-lan", oc.iface)
+	assert.Equal(t, "192.168.8.1", oc.gwIP)
+	assert.Equal(t, "255.255.255.0", oc.snMask)
+	assert.Equal(t, "192.168.8.100", oc.rangeStart)
+	assert.Equal(t, "192.168.8.249", oc.rangeEnd)
+	assert.Equal(t, uint32(43200), oc.leaseDur)
+	assert.Equal(t, "abab::1234", oc.bsDNS[0])
+	assert.Equal(t, "1.2.3.4", oc.bsDNS[1])
+
+	data = []byte(`config host '123412341234'
+option mac '12:34:12:34:12:34'
+option ip '192.168.8.2'
+option name 'hostname'`)
+	assert.True(t, nil == oc.readConfDHCPStatic(data))
+	assert.Equal(t, 1, len(oc.leases))
+	assert.Equal(t, "12:34:12:34:12:34", oc.leases[0].HWAddr.String())
+	assert.Equal(t, "192.168.8.2", oc.leases[0].IP.String())
+	assert.Equal(t, "hostname", oc.leases[0].Hostname)
+
+}