| // +build go1.9 |
| |
| /* |
| * |
| * Copyright 2018 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| package dns |
| |
| import ( |
| "net" |
| |
| "golang.org/x/net/context" |
| ) |
| |
| var ( |
| defaultResolver netResolver = net.DefaultResolver |
| ) |
| |
| const defaultDNSSvrPort = "53" |
| |
| var customAuthorityDialler = func(authority string) func(ctx context.Context, network, address string) (net.Conn, error) { |
| return func(ctx context.Context, network, address string) (net.Conn, error) { |
| var dialer net.Dialer |
| return dialer.DialContext(ctx, network, authority) |
| } |
| } |
| |
| var customAuthorityResolver = func(authority string) (netResolver, error) { |
| host, port, err := parseTarget(authority, defaultDNSSvrPort) |
| if err != nil { |
| return nil, err |
| } |
| |
| authorityWithPort := net.JoinHostPort(host, port) |
| |
| return &net.Resolver{ |
| PreferGo: true, |
| Dial: customAuthorityDialler(authorityWithPort), |
| }, nil |
| } |