package dnsfilter import ( "encoding/json" "fmt" "log" "net" "net/http" "os" "path" "runtime" "strconv" "strings" "sync" "time" "github.com/AdguardTeam/AdguardDNS/dnsfilter" "github.com/coredns/coredns/plugin/pkg/response" "github.com/miekg/dns" ) const ( logBufferCap = 5000 // maximum capacity of logBuffer before it's flushed to disk queryLogTimeLimit = time.Hour * 24 // how far in the past we care about querylogs queryLogRotationPeriod = time.Hour * 24 // rotate the log every 24 hours queryLogFileName = "querylog.json" // .gz added during compression queryLogCacheSize = 1000 // maximum API response for /querylog queryLogCacheTime = time.Minute // if requested more often than this, give out cached response queryLogTopSize = 500 // Keep in memory only top N values queryLogAPIPort = "8618" // 8618 is sha512sum of "querylog" then each byte summed ) var ( logBufferLock sync.RWMutex logBuffer []logEntry queryLogCache []logEntry queryLogLock sync.RWMutex queryLogTime time.Time ) type logEntry struct { Question []byte Answer []byte `json:",omitempty"` // sometimes empty answers happen like binerdunt.top or rev2.globalrootservers.net Result dnsfilter.Result Time time.Time Elapsed time.Duration IP string } func logRequest(question *dns.Msg, answer *dns.Msg, result dnsfilter.Result, elapsed time.Duration, ip string) { var q []byte var a []byte var err error if question != nil { q, err = question.Pack() if err != nil { log.Printf("failed to pack question for querylog: %s", err) return } } if answer != nil { a, err = answer.Pack() if err != nil { log.Printf("failed to pack answer for querylog: %s", err) return } } now := time.Now() entry := logEntry{ Question: q, Answer: a, Result: result, Time: now, Elapsed: elapsed, IP: ip, } var flushBuffer []logEntry logBufferLock.Lock() logBuffer = append(logBuffer, entry) if len(logBuffer) >= logBufferCap { flushBuffer = logBuffer logBuffer = nil } logBufferLock.Unlock() // add it to running top err = runningTop.addEntry(&entry, now) if err != nil { log.Printf("Failed to add entry to running top: %s", err) // don't do failure, just log } // if buffer needs to be flushed to disk, do it now if len(flushBuffer) > 0 { // write to file // do it in separate goroutine -- we are stalling DNS response this whole time go flushToFile(flushBuffer) } return } func handleQueryLog(w http.ResponseWriter, r *http.Request) { now := time.Now() queryLogLock.RLock() values := queryLogCache needRefresh := now.Sub(queryLogTime) >= queryLogCacheTime queryLogLock.RUnlock() if needRefresh { // need to get fresh data logBufferLock.RLock() values := logBuffer logBufferLock.RUnlock() if len(values) < queryLogCacheSize { values = appendFromLogFile(values, queryLogCacheSize, queryLogTimeLimit) } queryLogLock.Lock() queryLogCache = values queryLogTime = now queryLogLock.Unlock() } var data = []map[string]interface{}{} for _, entry := range values { var q *dns.Msg var a *dns.Msg if len(entry.Question) > 0 { q = new(dns.Msg) if err := q.Unpack(entry.Question); err != nil { // ignore, log and move on log.Printf("Failed to unpack dns message question: %s", err) q = nil } } if len(entry.Answer) > 0 { a = new(dns.Msg) if err := a.Unpack(entry.Answer); err != nil { // ignore, log and move on log.Printf("Failed to unpack dns message question: %s", err) a = nil } } jsonentry := map[string]interface{}{ "reason": entry.Result.Reason.String(), "elapsed_ms": strconv.FormatFloat(entry.Elapsed.Seconds()*1000, 'f', -1, 64), "time": entry.Time.Format(time.RFC3339), "client": entry.IP, } if q != nil { jsonentry["question"] = map[string]interface{}{ "host": strings.ToLower(strings.TrimSuffix(q.Question[0].Name, ".")), "type": dns.Type(q.Question[0].Qtype).String(), "class": dns.Class(q.Question[0].Qclass).String(), } } if a != nil { status, _ := response.Typify(a, time.Now().UTC()) jsonentry["status"] = status.String() } if len(entry.Result.Rule) > 0 { jsonentry["rule"] = entry.Result.Rule } if a != nil && len(a.Answer) > 0 { var answers = []map[string]interface{}{} for _, k := range a.Answer { header := k.Header() answer := map[string]interface{}{ "type": dns.TypeToString[header.Rrtype], "ttl": header.Ttl, } // try most common record types switch v := k.(type) { case *dns.A: answer["value"] = v.A case *dns.AAAA: answer["value"] = v.AAAA case *dns.MX: answer["value"] = fmt.Sprintf("%v %v", v.Preference, v.Mx) case *dns.CNAME: answer["value"] = v.Target case *dns.NS: answer["value"] = v.Ns case *dns.SPF: answer["value"] = v.Txt case *dns.TXT: answer["value"] = v.Txt case *dns.PTR: answer["value"] = v.Ptr case *dns.SOA: answer["value"] = fmt.Sprintf("%v %v %v %v %v %v %v", v.Ns, v.Mbox, v.Serial, v.Refresh, v.Retry, v.Expire, v.Minttl) case *dns.CAA: answer["value"] = fmt.Sprintf("%v %v \"%v\"", v.Flag, v.Tag, v.Value) case *dns.HINFO: answer["value"] = fmt.Sprintf("\"%v\" \"%v\"", v.Cpu, v.Os) case *dns.RRSIG: answer["value"] = fmt.Sprintf("%v %v %v %v %v %v %v %v %v", dns.TypeToString[v.TypeCovered], v.Algorithm, v.Labels, v.OrigTtl, v.Expiration, v.Inception, v.KeyTag, v.SignerName, v.Signature) default: // type unknown, marshall it as-is answer["value"] = v } answers = append(answers, answer) } jsonentry["answer"] = answers } data = append(data, jsonentry) } json, err := json.Marshal(data) if err != nil { errortext := fmt.Sprintf("Couldn't marshal data into json: %s", err) log.Println(errortext) http.Error(w, errortext, http.StatusInternalServerError) return } w.Header().Set("Content-Type", "application/json") _, err = w.Write(json) if err != nil { errortext := fmt.Sprintf("Unable to write response json: %s", err) log.Println(errortext) http.Error(w, errortext, http.StatusInternalServerError) } } func startQueryLogServer() { listenAddr := net.JoinHostPort("127.0.0.1", queryLogAPIPort) go periodicQueryLogRotate() go periodicHourlyTopRotate() http.HandleFunc("/querylog", handleQueryLog) http.HandleFunc("/stats_top", handleStatsTop) if err := http.ListenAndServe(listenAddr, nil); err != nil { log.Fatalf("error in ListenAndServe: %s", err) } } func trace(format string, args ...interface{}) { pc := make([]uintptr, 10) // at least 1 entry needed runtime.Callers(2, pc) f := runtime.FuncForPC(pc[0]) var buf strings.Builder buf.WriteString(fmt.Sprintf("%s(): ", path.Base(f.Name()))) text := fmt.Sprintf(format, args...) buf.WriteString(text) if len(text) == 0 || text[len(text)-1] != '\n' { buf.WriteRune('\n') } fmt.Fprint(os.Stderr, buf.String()) }