package dnsforward import ( "fmt" "net" "path/filepath" "strconv" "strings" "sync" "time" "github.com/AdguardTeam/AdGuardHome/dnsfilter" "github.com/AdguardTeam/golibs/log" "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 queryLogSize = 5000 // maximum API response for /querylog queryLogTopSize = 500 // Keep in memory only top N values ) // queryLog is a structure that writes and reads the DNS query log type queryLog struct { logFile string // path to the log file runningTop *dayTop // current top charts logBufferLock sync.RWMutex logBuffer []*logEntry fileFlushLock sync.Mutex // synchronize a file-flushing goroutine and main thread flushPending bool // don't start another goroutine while the previous one is still running queryLogCache []*logEntry queryLogLock sync.RWMutex } // newQueryLog creates a new instance of the query log func newQueryLog(baseDir string) *queryLog { l := &queryLog{ logFile: filepath.Join(baseDir, queryLogFileName), runningTop: &dayTop{}, } l.runningTop.init() return l } 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 Upstream string `json:",omitempty"` // if empty, means it was cached } func (l *queryLog) logRequest(question *dns.Msg, answer *dns.Msg, result *dnsfilter.Result, elapsed time.Duration, addr net.Addr, upstream string) *logEntry { var q []byte var a []byte var err error ip := getIPString(addr) if question != nil { q, err = question.Pack() if err != nil { log.Printf("failed to pack question for querylog: %s", err) return nil } } if answer != nil { a, err = answer.Pack() if err != nil { log.Printf("failed to pack answer for querylog: %s", err) return nil } } if result == nil { result = &dnsfilter.Result{} } now := time.Now() entry := logEntry{ Question: q, Answer: a, Result: *result, Time: now, Elapsed: elapsed, IP: ip, Upstream: upstream, } l.logBufferLock.Lock() l.logBuffer = append(l.logBuffer, &entry) needFlush := false if !l.flushPending { needFlush = len(l.logBuffer) >= logBufferCap if needFlush { l.flushPending = true } } l.logBufferLock.Unlock() l.queryLogLock.Lock() l.queryLogCache = append(l.queryLogCache, &entry) if len(l.queryLogCache) > queryLogSize { toremove := len(l.queryLogCache) - queryLogSize l.queryLogCache = l.queryLogCache[toremove:] } l.queryLogLock.Unlock() // add it to running top err = l.runningTop.addEntry(&entry, question, 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 needFlush { // write to file // do it in separate goroutine -- we are stalling DNS response this whole time go l.flushLogBuffer(false) } return &entry } // getQueryLogJson returns a map with the current query log ready to be converted to a JSON func (l *queryLog) getQueryLog() []map[string]interface{} { l.queryLogLock.RLock() values := make([]*logEntry, len(l.queryLogCache)) copy(values, l.queryLogCache) l.queryLogLock.RUnlock() // reverse it so that newest is first for left, right := 0, len(values)-1; left < right; left, right = left+1, right-1 { values[left], values[right] = values[right], values[left] } // iterate 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(), "elapsedMs": 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 { jsonEntry["status"] = dns.RcodeToString[a.Rcode] } if len(entry.Result.Rule) > 0 { jsonEntry["rule"] = entry.Result.Rule jsonEntry["filterId"] = entry.Result.FilterID } answers := answerToMap(a) if answers != nil { jsonEntry["answer"] = answers } data = append(data, jsonEntry) } return data } func answerToMap(a *dns.Msg) []map[string]interface{} { if a == nil || len(a.Answer) == 0 { return nil } 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) } return answers } // getIPString is a helper function that extracts IP address from net.Addr func getIPString(addr net.Addr) string { switch addr := addr.(type) { case *net.UDPAddr: return addr.IP.String() case *net.TCPAddr: return addr.IP.String() } return "" }