247 lines
6.5 KiB
Go
247 lines
6.5 KiB
Go
package dnsforward
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import (
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"fmt"
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"net"
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"path/filepath"
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"strconv"
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"strings"
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"sync"
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"time"
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"github.com/AdguardTeam/AdGuardHome/dnsfilter"
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"github.com/AdguardTeam/golibs/log"
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"github.com/miekg/dns"
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)
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const (
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logBufferCap = 5000 // maximum capacity of logBuffer before it's flushed to disk
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queryLogTimeLimit = time.Hour * 24 // how far in the past we care about querylogs
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queryLogRotationPeriod = time.Hour * 24 // rotate the log every 24 hours
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queryLogFileName = "querylog.json" // .gz added during compression
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queryLogSize = 5000 // maximum API response for /querylog
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queryLogTopSize = 500 // Keep in memory only top N values
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)
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// queryLog is a structure that writes and reads the DNS query log
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type queryLog struct {
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logFile string // path to the log file
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runningTop *dayTop // current top charts
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logBufferLock sync.RWMutex
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logBuffer []*logEntry
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fileFlushLock sync.Mutex // synchronize a file-flushing goroutine and main thread
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flushPending bool // don't start another goroutine while the previous one is still running
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queryLogCache []*logEntry
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queryLogLock sync.RWMutex
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}
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// newQueryLog creates a new instance of the query log
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func newQueryLog(baseDir string) *queryLog {
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l := &queryLog{
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logFile: filepath.Join(baseDir, queryLogFileName),
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runningTop: &dayTop{},
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}
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l.runningTop.init()
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return l
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}
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type logEntry struct {
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Question []byte
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Answer []byte `json:",omitempty"` // sometimes empty answers happen like binerdunt.top or rev2.globalrootservers.net
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Result dnsfilter.Result
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Time time.Time
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Elapsed time.Duration
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IP string
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Upstream string `json:",omitempty"` // if empty, means it was cached
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}
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func (l *queryLog) logRequest(question *dns.Msg, answer *dns.Msg, result *dnsfilter.Result, elapsed time.Duration, addr net.Addr, upstream string) *logEntry {
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var q []byte
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var a []byte
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var err error
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ip := GetIPString(addr)
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if question != nil {
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q, err = question.Pack()
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if err != nil {
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log.Printf("failed to pack question for querylog: %s", err)
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return nil
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}
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}
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if answer != nil {
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a, err = answer.Pack()
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if err != nil {
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log.Printf("failed to pack answer for querylog: %s", err)
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return nil
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}
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}
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if result == nil {
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result = &dnsfilter.Result{}
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}
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now := time.Now()
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entry := logEntry{
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Question: q,
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Answer: a,
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Result: *result,
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Time: now,
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Elapsed: elapsed,
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IP: ip,
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Upstream: upstream,
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}
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l.logBufferLock.Lock()
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l.logBuffer = append(l.logBuffer, &entry)
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needFlush := false
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if !l.flushPending {
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needFlush = len(l.logBuffer) >= logBufferCap
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if needFlush {
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l.flushPending = true
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}
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}
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l.logBufferLock.Unlock()
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l.queryLogLock.Lock()
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l.queryLogCache = append(l.queryLogCache, &entry)
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if len(l.queryLogCache) > queryLogSize {
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toremove := len(l.queryLogCache) - queryLogSize
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l.queryLogCache = l.queryLogCache[toremove:]
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}
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l.queryLogLock.Unlock()
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// add it to running top
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err = l.runningTop.addEntry(&entry, question, now)
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if err != nil {
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log.Printf("Failed to add entry to running top: %s", err)
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// don't do failure, just log
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}
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// if buffer needs to be flushed to disk, do it now
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if needFlush {
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// write to file
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// do it in separate goroutine -- we are stalling DNS response this whole time
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go l.flushLogBuffer(false)
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}
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return &entry
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}
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// getQueryLogJson returns a map with the current query log ready to be converted to a JSON
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func (l *queryLog) getQueryLog() []map[string]interface{} {
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l.queryLogLock.RLock()
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values := make([]*logEntry, len(l.queryLogCache))
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copy(values, l.queryLogCache)
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l.queryLogLock.RUnlock()
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// reverse it so that newest is first
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for left, right := 0, len(values)-1; left < right; left, right = left+1, right-1 {
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values[left], values[right] = values[right], values[left]
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}
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// iterate
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var data = []map[string]interface{}{}
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for _, entry := range values {
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var q *dns.Msg
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var a *dns.Msg
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if len(entry.Question) > 0 {
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q = new(dns.Msg)
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if err := q.Unpack(entry.Question); err != nil {
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// ignore, log and move on
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log.Printf("Failed to unpack dns message question: %s", err)
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q = nil
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}
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}
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if len(entry.Answer) > 0 {
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a = new(dns.Msg)
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if err := a.Unpack(entry.Answer); err != nil {
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// ignore, log and move on
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log.Printf("Failed to unpack dns message question: %s", err)
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a = nil
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}
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}
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jsonEntry := map[string]interface{}{
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"reason": entry.Result.Reason.String(),
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"elapsedMs": strconv.FormatFloat(entry.Elapsed.Seconds()*1000, 'f', -1, 64),
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"time": entry.Time.Format(time.RFC3339),
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"client": entry.IP,
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}
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if q != nil {
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jsonEntry["question"] = map[string]interface{}{
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"host": strings.ToLower(strings.TrimSuffix(q.Question[0].Name, ".")),
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"type": dns.Type(q.Question[0].Qtype).String(),
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"class": dns.Class(q.Question[0].Qclass).String(),
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}
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}
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if a != nil {
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jsonEntry["status"] = dns.RcodeToString[a.Rcode]
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}
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if len(entry.Result.Rule) > 0 {
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jsonEntry["rule"] = entry.Result.Rule
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jsonEntry["filterId"] = entry.Result.FilterID
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}
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answers := answerToMap(a)
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if answers != nil {
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jsonEntry["answer"] = answers
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}
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data = append(data, jsonEntry)
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}
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return data
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}
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func answerToMap(a *dns.Msg) []map[string]interface{} {
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if a == nil || len(a.Answer) == 0 {
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return nil
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}
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var answers = []map[string]interface{}{}
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for _, k := range a.Answer {
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header := k.Header()
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answer := map[string]interface{}{
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"type": dns.TypeToString[header.Rrtype],
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"ttl": header.Ttl,
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}
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// try most common record types
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switch v := k.(type) {
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case *dns.A:
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answer["value"] = v.A
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case *dns.AAAA:
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answer["value"] = v.AAAA
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case *dns.MX:
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answer["value"] = fmt.Sprintf("%v %v", v.Preference, v.Mx)
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case *dns.CNAME:
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answer["value"] = v.Target
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case *dns.NS:
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answer["value"] = v.Ns
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case *dns.SPF:
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answer["value"] = v.Txt
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case *dns.TXT:
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answer["value"] = v.Txt
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case *dns.PTR:
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answer["value"] = v.Ptr
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case *dns.SOA:
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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)
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case *dns.CAA:
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answer["value"] = fmt.Sprintf("%v %v \"%v\"", v.Flag, v.Tag, v.Value)
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case *dns.HINFO:
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answer["value"] = fmt.Sprintf("\"%v\" \"%v\"", v.Cpu, v.Os)
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case *dns.RRSIG:
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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)
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default:
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// type unknown, marshall it as-is
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answer["value"] = v
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}
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answers = append(answers, answer)
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}
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return answers
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}
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