From 630ec221088152615b2a34e2dfc33f7467b30b0a Mon Sep 17 00:00:00 2001
From: CalmLong <37164399+CalmLong@users.noreply.github.com>
Date: Wed, 10 Mar 2021 21:23:15 +0800
Subject: [PATCH] DNS: refine Android bootstrap DNS logic (#767)

---
 infra/conf/dns.go                   | 4 ----
 infra/conf/dns_bootstrap.go         | 9 ---------
 infra/conf/dns_bootstrap_android.go | 9 ++++-----
 3 files changed, 4 insertions(+), 18 deletions(-)
 delete mode 100644 infra/conf/dns_bootstrap.go

diff --git a/infra/conf/dns.go b/infra/conf/dns.go
index 8f08aeb11..bcf31a4c0 100644
--- a/infra/conf/dns.go
+++ b/infra/conf/dns.go
@@ -160,10 +160,6 @@ func (c *DNSConfig) Build() (*dns.Config, error) {
 		config.NameServer = append(config.NameServer, ns)
 	}
 
-	if BootstrapDNS() {
-		newError("Bootstrap DNS: ", bootstrapDNS).AtWarning().WriteToLog()
-	}
-
 	if c.Hosts != nil && len(c.Hosts) > 0 {
 		domains := make([]string, 0, len(c.Hosts))
 		for domain := range c.Hosts {
diff --git a/infra/conf/dns_bootstrap.go b/infra/conf/dns_bootstrap.go
deleted file mode 100644
index 3f741705c..000000000
--- a/infra/conf/dns_bootstrap.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// +build !android
-
-package conf
-
-const bootstrapDNS = ""
-
-func BootstrapDNS() bool {
-	return false
-}
diff --git a/infra/conf/dns_bootstrap_android.go b/infra/conf/dns_bootstrap_android.go
index cbb8a922f..0d56bbe89 100644
--- a/infra/conf/dns_bootstrap_android.go
+++ b/infra/conf/dns_bootstrap_android.go
@@ -7,12 +7,11 @@ import (
 	"net"
 )
 
-const bootstrapDNS = "8.8.8.8:53"
-
-func BootstrapDNS() bool {
+func init() {
+	const bootstrapDNS = "8.8.8.8:53"
 	var dialer net.Dialer
 	net.DefaultResolver = &net.Resolver{
-		PreferGo: false,
+		PreferGo: true,
 		Dial: func(context context.Context, _, _ string) (net.Conn, error) {
 			conn, err := dialer.DialContext(context, "udp", bootstrapDNS)
 			if err != nil {
@@ -21,5 +20,5 @@ func BootstrapDNS() bool {
 			return conn, nil
 		},
 	}
-	return true
+	newError("Bootstrap DNS: ", bootstrapDNS).AtWarning().WriteToLog()
 }