优化 socks 解析流程

server/fwd/socks/resolver.go

@@ -0,0 +1,21 @@
+package socks
+
+import (
+	"net"
+)
+
+// NameResolver 域名解析器
+type NameResolver interface {
+	Resolve(name string) (net.IP, error)
+}
+
+// DNSResolver 使用系统 dns 服务解析域名
+type DNSResolver struct{}
+
+func (d DNSResolver) Resolve(name string) (net.IP, error) {
+	addr, err := net.ResolveIPAddr("ip", name)
+	if err != nil {
+		return nil, err
+	}
+	return addr.IP, err
+}