145 lines
4.3 KiB
Go
145 lines
4.3 KiB
Go
/*
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*
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* Copyright 2017, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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package grpc
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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"net"
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"net/http"
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"net/http/httputil"
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"net/url"
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"golang.org/x/net/context"
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)
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var (
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// errDisabled indicates that proxy is disabled for the address.
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errDisabled = errors.New("proxy is disabled for the address")
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// The following variable will be overwritten in the tests.
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httpProxyFromEnvironment = http.ProxyFromEnvironment
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)
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func mapAddress(ctx context.Context, address string) (string, error) {
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req := &http.Request{
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URL: &url.URL{
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Scheme: "https",
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Host: address,
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},
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}
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url, err := httpProxyFromEnvironment(req)
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if err != nil {
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return "", err
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}
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if url == nil {
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return "", errDisabled
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}
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return url.Host, nil
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}
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// To read a response from a net.Conn, http.ReadResponse() takes a bufio.Reader.
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// It's possible that this reader reads more than what's need for the response and stores
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// those bytes in the buffer.
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// bufConn wraps the original net.Conn and the bufio.Reader to make sure we don't lose the
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// bytes in the buffer.
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type bufConn struct {
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net.Conn
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r io.Reader
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}
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func (c *bufConn) Read(b []byte) (int, error) {
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return c.r.Read(b)
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}
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func doHTTPConnectHandshake(ctx context.Context, conn net.Conn, addr string) (_ net.Conn, err error) {
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defer func() {
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if err != nil {
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conn.Close()
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}
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}()
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req := (&http.Request{
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Method: http.MethodConnect,
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URL: &url.URL{Host: addr},
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Header: map[string][]string{"User-Agent": {grpcUA}},
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})
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if err := sendHTTPRequest(ctx, req, conn); err != nil {
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return nil, fmt.Errorf("failed to write the HTTP request: %v", err)
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}
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r := bufio.NewReader(conn)
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resp, err := http.ReadResponse(r, req)
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if err != nil {
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return nil, fmt.Errorf("reading server HTTP response: %v", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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dump, err := httputil.DumpResponse(resp, true)
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if err != nil {
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return nil, fmt.Errorf("failed to do connect handshake, status code: %s", resp.Status)
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}
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return nil, fmt.Errorf("failed to do connect handshake, response: %q", dump)
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}
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return &bufConn{Conn: conn, r: r}, nil
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}
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// newProxyDialer returns a dialer that connects to proxy first if necessary.
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// The returned dialer checks if a proxy is necessary, dial to the proxy with the
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// provided dialer, does HTTP CONNECT handshake and returns the connection.
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func newProxyDialer(dialer func(context.Context, string) (net.Conn, error)) func(context.Context, string) (net.Conn, error) {
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return func(ctx context.Context, addr string) (conn net.Conn, err error) {
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var skipHandshake bool
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newAddr, err := mapAddress(ctx, addr)
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if err != nil {
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if err != errDisabled {
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return nil, err
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}
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skipHandshake = true
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newAddr = addr
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}
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conn, err = dialer(ctx, newAddr)
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if err != nil {
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return
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}
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if !skipHandshake {
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conn, err = doHTTPConnectHandshake(ctx, conn, addr)
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}
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return
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}
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}
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