From df0ab6aa8ede696d9bd2bae17f4e944b70db528a Mon Sep 17 00:00:00 2001
From: Dreamacro <305009791@qq.com>
Date: Mon, 17 Feb 2020 20:11:46 +0800
Subject: [PATCH] Fix: ipv6 dns crash

---
 dns/client.go   |  2 +-
 dns/resolver.go | 13 ++++++-------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/dns/client.go b/dns/client.go
index 1f1e6c6f..6341b657 100644
--- a/dns/client.go
+++ b/dns/client.go
@@ -26,7 +26,7 @@ func (c *client) ExchangeContext(ctx context.Context, m *D.Msg) (msg *D.Msg, err
 		network = "tcp"
 	}
 
-	ip, err := c.r.ResolveIPv4(c.host)
+	ip, err := c.r.ResolveIP(c.host)
 	if err != nil {
 		return nil, err
 	}
diff --git a/dns/resolver.go b/dns/resolver.go
index 480818c9..7d5fbc9c 100644
--- a/dns/resolver.go
+++ b/dns/resolver.go
@@ -44,23 +44,20 @@ type Resolver struct {
 	cache           *cache.Cache
 }
 
-// ResolveIP request with TypeA and TypeAAAA, priority return TypeAAAA
+// ResolveIP request with TypeA and TypeAAAA, priority return TypeA
 func (r *Resolver) ResolveIP(host string) (ip net.IP, err error) {
-	ch := make(chan net.IP)
+	ch := make(chan net.IP, 1)
 	go func() {
 		defer close(ch)
-		ip, err := r.resolveIP(host, D.TypeA)
+		ip, err := r.resolveIP(host, D.TypeAAAA)
 		if err != nil {
 			return
 		}
 		ch <- ip
 	}()
 
-	ip, err = r.resolveIP(host, D.TypeAAAA)
+	ip, err = r.resolveIP(host, D.TypeA)
 	if err == nil {
-		go func() {
-			<-ch
-		}()
 		return
 	}
 
@@ -216,6 +213,8 @@ func (r *Resolver) resolveIP(host string, dnsType uint16) (ip net.IP, err error)
 			return ip, nil
 		} else if dnsType == D.TypeA && isIPv4 {
 			return ip, nil
+		} else {
+			return nil, resolver.ErrIPVersion
 		}
 	}