badguardhome/dns.go

package main

import (
	"fmt"
	"net"
	"os"

	"github.com/AdguardTeam/AdGuardHome/dnsfilter"
	"github.com/AdguardTeam/AdGuardHome/dnsforward"
	"github.com/AdguardTeam/dnsproxy/proxy"
	"github.com/AdguardTeam/golibs/log"
	"github.com/joomcode/errorx"
)

var dnsServer *dnsforward.Server

// initDNSServer creates an instance of the dnsforward.Server
// Please note that we must do it even if we don't start it
// so that we had access to the query log and the stats
func initDNSServer(baseDir string) {
	err := os.MkdirAll(baseDir, 0755)
	if err != nil {
		log.Fatalf("Cannot create DNS data dir at %s: %s", baseDir, err)
	}

	dnsServer = dnsforward.NewServer(baseDir)
}

func isRunning() bool {
	return dnsServer != nil && dnsServer.IsRunning()
}

func generateServerConfig() dnsforward.ServerConfig {
	filters := []dnsfilter.Filter{}
	userFilter := userFilter()
	filters = append(filters, dnsfilter.Filter{
		ID:   userFilter.ID,
		Data: userFilter.Data,
	})
	for _, filter := range config.Filters {
		filters = append(filters, dnsfilter.Filter{
			ID:   filter.ID,
			Data: filter.Data,
		})
	}

	newconfig := dnsforward.ServerConfig{
		UDPListenAddr:   &net.UDPAddr{IP: net.ParseIP(config.DNS.BindHost), Port: config.DNS.Port},
		TCPListenAddr:   &net.TCPAddr{IP: net.ParseIP(config.DNS.BindHost), Port: config.DNS.Port},
		FilteringConfig: config.DNS.FilteringConfig,
		Filters:         filters,
	}
	bindhost := config.DNS.BindHost
	if config.DNS.BindHost == "0.0.0.0" {
		bindhost = "127.0.0.1"
	}
	newconfig.ResolverAddress = fmt.Sprintf("%s:%d", bindhost, config.DNS.Port)

	if config.TLS.Enabled {
		newconfig.TLSConfig = config.TLS.TLSConfig
		if config.TLS.PortDNSOverTLS != 0 {
			newconfig.TLSListenAddr = &net.TCPAddr{IP: net.ParseIP(config.DNS.BindHost), Port: config.TLS.PortDNSOverTLS}
		}
	}

	upstreamConfig, err := proxy.ParseUpstreamsConfig(config.DNS.UpstreamDNS, config.DNS.BootstrapDNS, dnsforward.DefaultTimeout)
	if err != nil {
		log.Error("Couldn't get upstreams configuration cause: %s", err)
	}
	newconfig.Upstreams = upstreamConfig.Upstreams
	newconfig.DomainsReservedUpstreams = upstreamConfig.DomainReservedUpstreams
	newconfig.AllServers = config.DNS.AllServers
	newconfig.FilterHandler = applyClientSettings
	return newconfig
}

// If a client has his own settings, apply them
func applyClientSettings(clientAddr string, setts *dnsfilter.RequestFilteringSettings) {
	c, ok := clientFind(clientAddr)
	if !ok || !c.UseOwnSettings {
		return
	}

	log.Debug("Using settings for client with IP %s", clientAddr)
	if !c.FilteringEnabled {
		setts.FilteringEnabled = false
	}
	if !c.SafeSearchEnabled {
		setts.SafeSearchEnabled = false
	}
	if !c.SafeBrowsingEnabled {
		setts.SafeBrowsingEnabled = false
	}
	if !c.ParentalEnabled {
		setts.ParentalEnabled = false
	}
}

func startDNSServer() error {
	if isRunning() {
		return fmt.Errorf("unable to start forwarding DNS server: Already running")
	}

	newconfig := generateServerConfig()
	err := dnsServer.Start(&newconfig)
	if err != nil {
		return errorx.Decorate(err, "Couldn't start forwarding DNS server")
	}

	return nil
}

func reconfigureDNSServer() error {
	if !isRunning() {
		return fmt.Errorf("Refusing to reconfigure forwarding DNS server: not running")
	}

	config := generateServerConfig()
	err := dnsServer.Reconfigure(&config)
	if err != nil {
		return errorx.Decorate(err, "Couldn't start forwarding DNS server")
	}

	return nil
}

func stopDNSServer() error {
	if !isRunning() {
		return fmt.Errorf("Refusing to stop forwarding DNS server: not running")
	}

	err := dnsServer.Stop()
	if err != nil {
		return errorx.Decorate(err, "Couldn't stop forwarding DNS server")
	}

	return nil
}