AdGuardHome/coredns_plugin/querylog.go

227 lines
5.7 KiB
Go

package dnsfilter
import (
"encoding/json"
"fmt"
"log"
"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 = 1000 // maximum capacity of logBuffer before it's flushed to disk
queryLogAPI = 1000 // maximum API response for /querylog
)
var (
logBufferLock sync.RWMutex
logBuffer []logEntry
)
type logEntry struct {
Question []byte
Answer []byte
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
}
}
entry := logEntry{
Question: q,
Answer: a,
Result: result,
Time: 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()
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) {
// TODO: fetch values from disk if len(logBuffer) < queryLogSize
// TODO: cache output
logBufferLock.RLock()
values := logBuffer
logBufferLock.RUnlock()
if len(values) < queryLogAPI {
values = appendFromLogFile(values, queryLogAPI, time.Hour*24)
}
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, 500)
}
}
func startQueryLogServer() {
listenAddr := "127.0.0.1:8618" // 8618 is sha512sum of "querylog" then each byte summed
go periodicQueryLogRotate(queryLogRotationPeriod)
http.HandleFunc("/querylog", handleQueryLog)
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())
}