package main import ( "bytes" "io/ioutil" "log" "os" "path/filepath" "regexp" "sync" "text/template" "time" "gopkg.in/yaml.v2" ) // configuration is loaded from YAML type configuration struct { ourConfigFilename string ourBinaryDir string BindHost string `yaml:"bind_host"` BindPort int `yaml:"bind_port"` AuthName string `yaml:"auth_name"` AuthPass string `yaml:"auth_pass"` CoreDNS coreDNSConfig `yaml:"coredns"` Filters []filter `yaml:"filters"` UserRules []string `yaml:"user_rules"` sync.RWMutex `yaml:"-"` } type coreDNSConfig struct { binaryFile string coreFile string FilterFile string `yaml:"-"` Port int `yaml:"port"` ProtectionEnabled bool `yaml:"protection_enabled"` FilteringEnabled bool `yaml:"filtering_enabled"` SafeBrowsingEnabled bool `yaml:"safebrowsing_enabled"` SafeSearchEnabled bool `yaml:"safesearch_enabled"` ParentalEnabled bool `yaml:"parental_enabled"` ParentalSensitivity int `yaml:"parental_sensitivity"` BlockedResponseTTL int `yaml:"blocked_response_ttl"` QueryLogEnabled bool `yaml:"querylog_enabled"` Pprof string `yaml:"-"` Cache string `yaml:"-"` Prometheus string `yaml:"-"` UpstreamDNS []string `yaml:"upstream_dns"` } type filter struct { URL string `json:"url"` Name string `json:"name" yaml:"name"` Enabled bool `json:"enabled"` RulesCount int `json:"rules_count" yaml:"-"` contents []byte LastUpdated time.Time `json:"last_updated" yaml:"-"` } var defaultDNS = []string{"tls://1.1.1.1", "tls://1.0.0.1"} // initialize to default values, will be changed later when reading config or parsing command line var config = configuration{ ourConfigFilename: "AdguardDNS.yaml", BindPort: 3000, BindHost: "127.0.0.1", CoreDNS: coreDNSConfig{ Port: 53, binaryFile: "coredns", // only filename, no path coreFile: "Corefile", // only filename, no path FilterFile: "dnsfilter.txt", // only filename, no path ProtectionEnabled: true, FilteringEnabled: true, SafeBrowsingEnabled: false, BlockedResponseTTL: 10, // in seconds QueryLogEnabled: true, UpstreamDNS: defaultDNS, Cache: "cache", Prometheus: "prometheus :9153", }, Filters: []filter{ {Enabled: true, URL: "https://adguardteam.github.io/AdGuardSDNSFilter/Filters/filter.txt"}, {Enabled: false, URL: "https://adaway.org/hosts.txt", Name: "AdAway"}, {Enabled: false, URL: "https://hosts-file.net/ad_servers.txt", Name: "hpHosts - Ad and Tracking servers only"}, {Enabled: false, URL: "http://www.malwaredomainlist.com/hostslist/hosts.txt", Name: "MalwareDomainList.com Hosts List"}, }, } func parseConfig() error { configfile := filepath.Join(config.ourBinaryDir, config.ourConfigFilename) log.Printf("Reading YAML file: %s", configfile) if _, err := os.Stat(configfile); os.IsNotExist(err) { // do nothing, file doesn't exist log.Printf("YAML file doesn't exist, skipping: %s", configfile) return nil } yamlFile, err := ioutil.ReadFile(configfile) if err != nil { log.Printf("Couldn't read config file: %s", err) return err } err = yaml.Unmarshal(yamlFile, &config) if err != nil { log.Printf("Couldn't parse config file: %s", err) return err } return nil } func writeConfig() error { configfile := filepath.Join(config.ourBinaryDir, config.ourConfigFilename) log.Printf("Writing YAML file: %s", configfile) yamlText, err := yaml.Marshal(&config) if err != nil { log.Printf("Couldn't generate YAML file: %s", err) return err } err = ioutil.WriteFile(configfile+".tmp", yamlText, 0644) if err != nil { log.Printf("Couldn't write YAML config: %s", err) return err } err = os.Rename(configfile+".tmp", configfile) if err != nil { log.Printf("Couldn't rename YAML config: %s", err) return err } return nil } // -------------- // coredns config // -------------- func writeCoreDNSConfig() error { corefile := filepath.Join(config.ourBinaryDir, config.CoreDNS.coreFile) log.Printf("Writing DNS config: %s", corefile) configtext, err := generateCoreDNSConfigText() if err != nil { log.Printf("Couldn't generate DNS config: %s", err) return err } err = ioutil.WriteFile(corefile+".tmp", []byte(configtext), 0644) if err != nil { log.Printf("Couldn't write DNS config: %s", err) } err = os.Rename(corefile+".tmp", corefile) if err != nil { log.Printf("Couldn't rename DNS config: %s", err) } return err } func writeAllConfigs() error { err := writeConfig() if err != nil { log.Printf("Couldn't write our config: %s", err) return err } err = writeCoreDNSConfig() if err != nil { log.Printf("Couldn't write DNS config: %s", err) return err } return nil } const coreDNSConfigTemplate = `. { {{if .ProtectionEnabled}}dnsfilter {{if .FilteringEnabled}}{{.FilterFile}}{{end}} { {{if .SafeBrowsingEnabled}}safebrowsing{{end}} {{if .ParentalEnabled}}parental {{.ParentalSensitivity}}{{end}} {{if .SafeSearchEnabled}}safesearch{{end}} {{if .QueryLogEnabled}}querylog{{end}} blocked_ttl {{.BlockedResponseTTL}} }{{end}} {{.Pprof}} hosts { fallthrough } {{if .UpstreamDNS}}forward . {{range .UpstreamDNS}}{{.}} {{end}}{{end}} {{.Cache}} {{.Prometheus}} } ` var removeEmptyLines = regexp.MustCompile("([\t ]*\n)+") // generate config text func generateCoreDNSConfigText() (string, error) { t, err := template.New("config").Parse(coreDNSConfigTemplate) if err != nil { log.Printf("Couldn't generate DNS config: %s", err) return "", err } var configBytes bytes.Buffer // run the template err = t.Execute(&configBytes, config.CoreDNS) if err != nil { log.Printf("Couldn't generate DNS config: %s", err) return "", err } configtext := configBytes.String() // remove empty lines from generated config configtext = removeEmptyLines.ReplaceAllString(configtext, "\n") return configtext, nil }