| /* |
| * |
| * Copyright 2017 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 transport |
| |
| import ( |
| "bufio" |
| "context" |
| "encoding/base64" |
| "fmt" |
| "io" |
| "net" |
| "net/http" |
| "net/http/httputil" |
| "net/url" |
| ) |
| |
| const proxyAuthHeaderKey = "Proxy-Authorization" |
| |
| var ( |
| // The following variable will be overwritten in the tests. |
| httpProxyFromEnvironment = http.ProxyFromEnvironment |
| ) |
| |
| func mapAddress(ctx context.Context, address string) (*url.URL, error) { |
| req := &http.Request{ |
| URL: &url.URL{ |
| Scheme: "https", |
| Host: address, |
| }, |
| } |
| url, err := httpProxyFromEnvironment(req) |
| if err != nil { |
| return nil, err |
| } |
| return url, nil |
| } |
| |
| // To read a response from a net.Conn, http.ReadResponse() takes a bufio.Reader. |
| // It's possible that this reader reads more than what's need for the response and stores |
| // those bytes in the buffer. |
| // bufConn wraps the original net.Conn and the bufio.Reader to make sure we don't lose the |
| // bytes in the buffer. |
| type bufConn struct { |
| net.Conn |
| r io.Reader |
| } |
| |
| func (c *bufConn) Read(b []byte) (int, error) { |
| return c.r.Read(b) |
| } |
| |
| func basicAuth(username, password string) string { |
| auth := username + ":" + password |
| return base64.StdEncoding.EncodeToString([]byte(auth)) |
| } |
| |
| func doHTTPConnectHandshake(ctx context.Context, conn net.Conn, backendAddr string, proxyURL *url.URL, grpcUA string) (_ net.Conn, err error) { |
| defer func() { |
| if err != nil { |
| conn.Close() |
| } |
| }() |
| |
| req := &http.Request{ |
| Method: http.MethodConnect, |
| URL: &url.URL{Host: backendAddr}, |
| Header: map[string][]string{"User-Agent": {grpcUA}}, |
| } |
| if t := proxyURL.User; t != nil { |
| u := t.Username() |
| p, _ := t.Password() |
| req.Header.Add(proxyAuthHeaderKey, "Basic "+basicAuth(u, p)) |
| } |
| |
| if err := sendHTTPRequest(ctx, req, conn); err != nil { |
| return nil, fmt.Errorf("failed to write the HTTP request: %v", err) |
| } |
| |
| r := bufio.NewReader(conn) |
| resp, err := http.ReadResponse(r, req) |
| if err != nil { |
| return nil, fmt.Errorf("reading server HTTP response: %v", err) |
| } |
| defer resp.Body.Close() |
| if resp.StatusCode != http.StatusOK { |
| dump, err := httputil.DumpResponse(resp, true) |
| if err != nil { |
| return nil, fmt.Errorf("failed to do connect handshake, status code: %s", resp.Status) |
| } |
| return nil, fmt.Errorf("failed to do connect handshake, response: %q", dump) |
| } |
| |
| return &bufConn{Conn: conn, r: r}, nil |
| } |
| |
| // proxyDial dials, connecting to a proxy first if necessary. Checks if a proxy |
| // is necessary, dials, does the HTTP CONNECT handshake, and returns the |
| // connection. |
| func proxyDial(ctx context.Context, addr string, grpcUA string) (conn net.Conn, err error) { |
| newAddr := addr |
| proxyURL, err := mapAddress(ctx, addr) |
| if err != nil { |
| return nil, err |
| } |
| if proxyURL != nil { |
| newAddr = proxyURL.Host |
| } |
| |
| conn, err = (&net.Dialer{}).DialContext(ctx, "tcp", newAddr) |
| if err != nil { |
| return |
| } |
| if proxyURL != nil { |
| // proxy is disabled if proxyURL is nil. |
| conn, err = doHTTPConnectHandshake(ctx, conn, addr, proxyURL, grpcUA) |
| } |
| return |
| } |
| |
| func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error { |
| req = req.WithContext(ctx) |
| if err := req.Write(conn); err != nil { |
| return fmt.Errorf("failed to write the HTTP request: %v", err) |
| } |
| return nil |
| } |