1.4.5.2

EdgeAdmin/internal/utils/lookup.go

@@ -0,0 +1,81 @@
+package utils
+
+import (
+	teaconst "github.com/TeaOSLab/EdgeAdmin/internal/const"
+	"github.com/TeaOSLab/EdgeCommon/pkg/configutils"
+	"github.com/iwind/TeaGo/lists"
+	"github.com/iwind/TeaGo/logs"
+	"github.com/miekg/dns"
+	"sync"
+)
+
+var sharedDNSClient *dns.Client
+var sharedDNSConfig *dns.ClientConfig
+
+func init() {
+	if !teaconst.IsMain {
+		return
+	}
+
+	config, err := dns.ClientConfigFromFile("/etc/resolv.conf")
+	if err != nil {
+		logs.Println("ERROR: configure dns client failed: " + err.Error())
+		return
+	}
+
+	sharedDNSConfig = config
+	sharedDNSClient = &dns.Client{}
+}
+
+// LookupCNAME 获取CNAME
+func LookupCNAME(host string) (string, error) {
+	var m = new(dns.Msg)
+
+	m.SetQuestion(host+".", dns.TypeCNAME)
+	m.RecursionDesired = true
+
+	var lastErr error
+	var success = false
+	var result = ""
+
+	var serverAddrs = sharedDNSConfig.Servers
+
+	{
+		var publicDNSHosts = []string{"8.8.8.8" /** Google **/, "8.8.4.4" /** Google **/}
+		for _, publicDNSHost := range publicDNSHosts {
+			if !lists.ContainsString(serverAddrs, publicDNSHost) {
+				serverAddrs = append(serverAddrs, publicDNSHost)
+			}
+		}
+	}
+
+	var wg = &sync.WaitGroup{}
+
+	for _, serverAddr := range serverAddrs {
+		wg.Add(1)
+
+		go func(serverAddr string) {
+			defer wg.Done()
+			r, _, err := sharedDNSClient.Exchange(m, configutils.QuoteIP(serverAddr)+":"+sharedDNSConfig.Port)
+			if err != nil {
+				lastErr = err
+				return
+			}
+
+			success = true
+
+			if len(r.Answer) == 0 {
+				return
+			}
+
+			result = r.Answer[0].(*dns.CNAME).Target
+		}(serverAddr)
+	}
+	wg.Wait()
+
+	if success {
+		return result, nil
+	}
+
+	return "", lastErr
+}