Merge pull request #66 in DNS/adguard-dns from bugfix/356 to master

* commit 'e689c7d940e9a20bc13f024e18b86f3c1e5ba759':
  Do not lose filter name when saving to yaml
  coredns querylog -- since we read entire querylog json once at startup, fill querylog cache from it and then rotate it on each incoming DNS query
  Cache DNS lookups when resolving safebrowsing or parental servers, also cache replacement hostnames as well.

config.go

@@ -50,7 +50,7 @@ type coreDNSConfig struct {
 
 type filter struct {
 	URL         string `json:"url"`
-	Name        string `json:"name" yaml:"-"`
+	Name        string `json:"name" yaml:"name"`
 	Enabled     bool   `json:"enabled"`
 	RulesCount  int    `json:"rules_count" yaml:"-"`
 	contents    []byte

coredns_plugin/coredns_plugin.go

@@ -45,6 +45,16 @@ func init() {
 	})
 }
 
+type cacheEntry struct {
+	answer      []dns.RR
+	lastUpdated time.Time
+}
+
+var (
+	lookupCacheTime = time.Minute * 30
+	lookupCache     = map[string]cacheEntry{}
+)
+
 type plugSettings struct {
 	SafeBrowsingBlockHost string
 	ParentalBlockHost     string
@@ -324,20 +334,29 @@ func (p *plug) replaceHostWithValAndReply(ctx context.Context, w dns.ResponseWri
 		records = append(records, result)
 	} else {
 		// this is a domain name, need to look it up
-		req := new(dns.Msg)
-		req.SetQuestion(dns.Fqdn(val), question.Qtype)
-		req.RecursionDesired = true
-		reqstate := request.Request{W: w, Req: req, Context: ctx}
-		result, err := p.upstream.Lookup(reqstate, dns.Fqdn(val), reqstate.QType())
-		if err != nil {
-			log.Printf("Got error %s\n", err)
-			return dns.RcodeServerFailure, fmt.Errorf("plugin/dnsfilter: %s", err)
-		}
-		if result != nil {
-			for _, answer := range result.Answer {
-				answer.Header().Name = question.Name
+		cacheentry := lookupCache[val]
+		if time.Since(cacheentry.lastUpdated) > lookupCacheTime {
+			req := new(dns.Msg)
+			req.SetQuestion(dns.Fqdn(val), question.Qtype)
+			req.RecursionDesired = true
+			reqstate := request.Request{W: w, Req: req, Context: ctx}
+			result, err := p.upstream.Lookup(reqstate, dns.Fqdn(val), reqstate.QType())
+			if err != nil {
+				log.Printf("Got error %s\n", err)
+				return dns.RcodeServerFailure, fmt.Errorf("plugin/dnsfilter: %s", err)
 			}
-			records = result.Answer
+			if result != nil {
+				for _, answer := range result.Answer {
+					answer.Header().Name = question.Name
+				}
+				records = result.Answer
+				cacheentry.answer = result.Answer
+				cacheentry.lastUpdated = time.Now()
+				lookupCache[val] = cacheentry
+			}
+		} else {
+			// get from cache
+			records = cacheentry.answer
 		}
 	}
 	m := new(dns.Msg)

coredns_plugin/querylog.go

@@ -25,16 +25,15 @@ const (
 	queryLogRotationPeriod = time.Hour * 24  // rotate the log every 24 hours
 	queryLogFileName       = "querylog.json" // .gz added during compression
 	queryLogSize           = 5000            // 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
+	logBuffer     []*logEntry
 
-	queryLogCache []logEntry
+	queryLogCache []*logEntry
 	queryLogLock  sync.RWMutex
 	queryLogTime  time.Time
 )
@@ -77,15 +76,22 @@ func logRequest(question *dns.Msg, answer *dns.Msg, result dnsfilter.Result, ela
 		Elapsed:  elapsed,
 		IP:       ip,
 	}
-	var flushBuffer []logEntry
+	var flushBuffer []*logEntry
 
 	logBufferLock.Lock()
-	logBuffer = append(logBuffer, entry)
+	logBuffer = append(logBuffer, &entry)
 	if len(logBuffer) >= logBufferCap {
 		flushBuffer = logBuffer
 		logBuffer = nil
 	}
 	logBufferLock.Unlock()
+	queryLogLock.Lock()
+	queryLogCache = append(queryLogCache, &entry)
+	if len(queryLogCache) > queryLogSize {
+		toremove := len(queryLogCache) - queryLogSize
+		queryLogCache = queryLogCache[toremove:]
+	}
+	queryLogLock.Unlock()
 
 	// add it to running top
 	err = runningTop.addEntry(&entry, question, now)
@@ -103,26 +109,14 @@ func logRequest(question *dns.Msg, answer *dns.Msg, result dnsfilter.Result, ela
 }
 
 func handleQueryLog(w http.ResponseWriter, r *http.Request) {
-	now := time.Now()
-
 	queryLogLock.RLock()
-	values := queryLogCache
-	needRefresh := now.Sub(queryLogTime) >= queryLogCacheTime
+	values := make([]*logEntry, len(queryLogCache))
+	copy(values, queryLogCache)
 	queryLogLock.RUnlock()
 
-	if needRefresh {
-		// need to get fresh data
-		logBufferLock.RLock()
-		values = logBuffer
-		logBufferLock.RUnlock()
-
-		if len(values) < queryLogSize {
-			values = appendFromLogFile(values, queryLogSize, queryLogTimeLimit)
-		}
-		queryLogLock.Lock()
-		queryLogCache = values
-		queryLogTime = now
-		queryLogLock.Unlock()
+	// 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]
 	}
 
 	var data = []map[string]interface{}{}

coredns_plugin/querylog_file.go

@@ -19,7 +19,7 @@ var (
 
 const enableGzip = false
 
-func flushToFile(buffer []logEntry) error {
+func flushToFile(buffer []*logEntry) error {
 	if len(buffer) == 0 {
 		return nil
 	}
@@ -90,7 +90,7 @@ func flushToFile(buffer []logEntry) error {
 	return nil
 }
 
-func checkBuffer(buffer []logEntry, b bytes.Buffer) error {
+func checkBuffer(buffer []*logEntry, b bytes.Buffer) error {
 	l := len(buffer)
 	d := json.NewDecoder(&b)
 
@@ -237,11 +237,11 @@ func genericLoader(onEntry func(entry *logEntry) error, needMore func() bool, ti
 	return nil
 }
 
-func appendFromLogFile(values []logEntry, maxLen int, timeWindow time.Duration) []logEntry {
-	a := []logEntry{}
+func appendFromLogFile(values []*logEntry, maxLen int, timeWindow time.Duration) []*logEntry {
+	a := []*logEntry{}
 
 	onEntry := func(entry *logEntry) error {
-		a = append(a, *entry)
+		a = append(a, entry)
 		if len(a) > maxLen {
 			toskip := len(a) - maxLen
 			a = a[toskip:]

coredns_plugin/querylog_top.go

@@ -223,6 +223,14 @@ func fillStatsFromQueryLog() error {
 			return err
 		}
 
+		queryLogLock.Lock()
+		queryLogCache = append(queryLogCache, entry)
+		if len(queryLogCache) > queryLogSize {
+			toremove := len(queryLogCache) - queryLogSize
+			queryLogCache = queryLogCache[toremove:]
+		}
+		queryLogLock.Unlock()
+
 		requests.IncWithTime(entry.Time)
 		if entry.Result.IsFiltered {
 			filtered.IncWithTime(entry.Time)

dnsfilter/dnsfilter.go

@@ -16,6 +16,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	_ "github.com/benburkert/dns/init"
 	"github.com/bluele/gcache"
 	"golang.org/x/net/publicsuffix"
 )