添加 docker-compose.yml

internal/handler/handler.go

@@ -7,7 +7,6 @@ import (
 	"strings"
 	"sync"
 	"time"
-	"strconv"
 
 	"github.com/miekg/dns"
 
@@ -165,19 +164,21 @@ func (h *Handler) exchange(req *dns.Msg) *dns.Msg {
 }
 
 func getDnsRequestCacheKey(m *dns.Msg) string {
-	if len(m.Question) == 0 {
+	var dnssec string
-		return ""
+	if o := m.IsEdns0(); o != nil {
+		// 区分 DNSSEC 请求，避免将非 DNSSEC 响应返回给需要 DNSSEC 的客户端
+		if o.Do() {
+			dnssec = "DO"
 		}
-	
+		// 服务多区域的公共dns使用
-	var b strings.Builder
+		// for _, s := range o.Option {
-	b.Grow(64)
+		// 	switch e := s.(type) {
-	b.WriteString(model.GetDomainNameFromDnsMsg(m))
+		// 	case *dns.EDNS0_SUBNET:
-	b.WriteByte('#')
+		// 		edns = e.Address.String()
-	b.WriteString(strconv.Itoa(int(m.Question[0].Qtype)))
+		// 	}
-	if o := m.IsEdns0(); o != nil && o.Do() {
+		// }
-		b.WriteString("#DO")
 	}
-	return b.String()
+	return fmt.Sprintf("%s#%d#%s", model.GetDomainNameFromDnsMsg(m), m.Question[0].Qtype, dnssec)
 }
 
 func getDnsResponseTtl(m *dns.Msg) time.Duration {
@@ -416,14 +417,8 @@ func (h *Handler) HandleRequest(w dns.ResponseWriter, req *dns.Msg) {
 	}
 }
 
-var builderPool = sync.Pool{
+// uniqueAnswer 去除重复的 DNS 资源记录
-	New: func() interface{} {
+// 基于域名、类型和记录数据进行去重，比字符串分割更高效和可靠
-		b := new(strings.Builder)
-		b.Grow(128)
-		return b
-	},
-}
-
 func uniqueAnswer(records []dns.RR) []dns.RR {
 	if len(records) == 0 {
 		return records
@@ -442,7 +437,10 @@ func uniqueAnswer(records []dns.RR) []dns.RR {
 			continue
 		}
 
-		builder := builderPool.Get().(*strings.Builder)
+		// 构造唯一键：域名 + 类型 + 记录数据
+		// 使用 strings.Builder 优化字符串拼接性能
+		var builder strings.Builder
+		builder.Grow(128) // Pre-allocate reasonable capacity
 
 		var key string
 		switch v := rr.(type) {
@@ -494,10 +492,9 @@ func uniqueAnswer(records []dns.RR) []dns.RR {
 			builder.WriteString(v.Mbox)
 			key = builder.String()
 		default:
+			// 对于其他类型，回退到完整字符串表示
 			key = rr.String()
 		}
-		builder.Reset()
-		builderPool.Put(builder)
 
 		if !seen[key] {
 			seen[key] = true
@@ -554,6 +551,7 @@ func (h *Handler) getTheFastestResults(req *dns.Msg) []*dns.Msg {
 		go func(j int) {
 			msg, _, err := preferUpstreams[j].Exchange(req.Copy())
 
+			// 记录上游服务器统计
 			if h.stats != nil {
 				h.stats.RecordUpstreamQuery(preferUpstreams[j].Address, err != nil)
 			}
@@ -565,12 +563,12 @@ func (h *Handler) getTheFastestResults(req *dns.Msg) []*dns.Msg {
 			mutex.Lock()
 			defer mutex.Unlock()
 
+			finishedCount++
+			// 已经结束直接退出
 			if finished {
 				return
 			}
 
-			finishedCount++
-
 			if err == nil {
 				if preferUpstreams[j].IsValidMsg(msg) {
 					if preferUpstreams[j].IsPrimary {
@@ -580,15 +578,27 @@ func (h *Handler) getTheFastestResults(req *dns.Msg) []*dns.Msg {
 					}
 					msgs[j] = msg
 				} else if preferUpstreams[j].IsPrimary {
+					// 策略：国内 DNS 返回了 国外 服务器，计数但是不记入结果，以 国外 DNS 为准
 					primaryIndex = append(primaryIndex, j)
 				}
 			}
 
-			shouldFinish := finishedCount == len(preferUpstreams) ||
+			// 全部结束直接退出
-				(len(primaryIndex) > 0 && len(freedomIndex) > 0) ||
+			if finishedCount == len(preferUpstreams) {
-				(len(primaryIndex) > 0 && (msgs[primaryIndex[0]] != nil || len(freedomIndex) > 0))
+				finished = true
-			
+				wg.Done()
-			if shouldFinish && !finished {
+				return
+			}
+			// 两组 DNS 都有一个返回结果，退出
+			if len(primaryIndex) > 0 && len(freedomIndex) > 0 {
+				finished = true
+				wg.Done()
+				return
+			}
+			// 满足任一条件退出
+			//  - 国内 DNS 返回了 国内 服务器
+			//  - 国内 DNS 返回国外服务器 且 国外 DNS 有可用结果
+			if len(primaryIndex) > 0 && (msgs[primaryIndex[0]] != nil || len(freedomIndex) > 0) {
 				finished = true
 				wg.Done()
 			}
@@ -601,19 +611,19 @@ func (h *Handler) getTheFastestResults(req *dns.Msg) []*dns.Msg {
 
 func (h *Handler) getAnyResult(req *dns.Msg) []*dns.Msg {
 	matchedUpstreams := h.matchedUpstreams(req)
-	msgs := make([]*dns.Msg, len(matchedUpstreams))
-
-	var mutex sync.Mutex
-	var finishedCount int
-	var finished bool
 
 	var wg sync.WaitGroup
 	wg.Add(1)
+	msgs := make([]*dns.Msg, len(matchedUpstreams))
+	var mutex sync.Mutex
+	var finishedCount int
+	var finished bool
 
 	for i := 0; i < len(matchedUpstreams); i++ {
 		go func(j int) {
 			msg, _, err := matchedUpstreams[j].Exchange(req.Copy())
 
+			// 记录上游服务器统计
 			if h.stats != nil {
 				h.stats.RecordUpstreamQuery(matchedUpstreams[j].Address, err != nil)
 			}
@@ -621,18 +631,16 @@ func (h *Handler) getAnyResult(req *dns.Msg) []*dns.Msg {
 			if err != nil {
 				h.logger.Printf("upstream error %s: %v %s", matchedUpstreams[j].Address, model.GetDomainNameFromDnsMsg(req), err)
 			}
-
 			mutex.Lock()
 			defer mutex.Unlock()
 
+			finishedCount++
 			if finished {
 				return
 			}
 
-			finishedCount++
+			// 已结束或任意上游返回成功时退出
-			shouldFinish := err == nil || finishedCount == len(matchedUpstreams)
+			if err == nil || finishedCount == len(matchedUpstreams) {
-			
-			if shouldFinish && !finished {
 				finished = true
 				msgs[j] = msg
 				wg.Done()