third_party/grpc/src/core/ext/filters/client_channel/http_connect_handshaker.cc - bazel - Git at Google

 /*
  *
  * Copyright 2016 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.
  *
  */

 #include <grpc/support/port_platform.h>

 #include "src/core/ext/filters/client_channel/http_connect_handshaker.h"

 #include <string.h>

 #include <grpc/slice_buffer.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>

 #include "src/core/ext/filters/client_channel/client_channel.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/handshaker_registry.h"
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/http/format_request.h"
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/uri/uri_parser.h"

 typedef struct http_connect_handshaker {
   // Base class.  Must be first.
   grpc_handshaker base;

   gpr_refcount refcount;
   gpr_mu mu;

   bool shutdown;
   // Endpoint and read buffer to destroy after a shutdown.
   grpc_endpoint* endpoint_to_destroy;
   grpc_slice_buffer* read_buffer_to_destroy;

   // State saved while performing the handshake.
   grpc_handshaker_args* args;
   grpc_closure* on_handshake_done;

   // Objects for processing the HTTP CONNECT request and response.
   grpc_slice_buffer write_buffer;
   grpc_closure request_done_closure;
   grpc_closure response_read_closure;
   grpc_http_parser http_parser;
   grpc_http_response http_response;
 } http_connect_handshaker;

 // Unref and clean up handshaker.
 static void http_connect_handshaker_unref(http_connect_handshaker* handshaker) {
   if (gpr_unref(&handshaker->refcount)) {
     gpr_mu_destroy(&handshaker->mu);
     if (handshaker->endpoint_to_destroy != nullptr) {
       grpc_endpoint_destroy(handshaker->endpoint_to_destroy);
     }
     if (handshaker->read_buffer_to_destroy != nullptr) {
       grpc_slice_buffer_destroy_internal(handshaker->read_buffer_to_destroy);
       gpr_free(handshaker->read_buffer_to_destroy);
     }
     grpc_slice_buffer_destroy_internal(&handshaker->write_buffer);
     grpc_http_parser_destroy(&handshaker->http_parser);
     grpc_http_response_destroy(&handshaker->http_response);
     gpr_free(handshaker);
   }
 }

 // Set args fields to nullptr, saving the endpoint and read buffer for
 // later destruction.
 static void cleanup_args_for_failure_locked(
     http_connect_handshaker* handshaker) {
   handshaker->endpoint_to_destroy = handshaker->args->endpoint;
   handshaker->args->endpoint = nullptr;
   handshaker->read_buffer_to_destroy = handshaker->args->read_buffer;
   handshaker->args->read_buffer = nullptr;
   grpc_channel_args_destroy(handshaker->args->args);
   handshaker->args->args = nullptr;
 }

 // If the handshake failed or we're shutting down, clean up and invoke the
 // callback with the error.
 static void handshake_failed_locked(http_connect_handshaker* handshaker,
                                     grpc_error* error) {
   if (error == GRPC_ERROR_NONE) {
     // If we were shut down after an endpoint operation succeeded but
     // before the endpoint callback was invoked, we need to generate our
     // own error.
     error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshaker shutdown");
   }
   if (!handshaker->shutdown) {
     // TODO(ctiller): It is currently necessary to shutdown endpoints
     // before destroying them, even if we know that there are no
     // pending read/write callbacks.  This should be fixed, at which
     // point this can be removed.
     grpc_endpoint_shutdown(handshaker->args->endpoint, GRPC_ERROR_REF(error));
     // Not shutting down, so the handshake failed.  Clean up before
     // invoking the callback.
     cleanup_args_for_failure_locked(handshaker);
     // Set shutdown to true so that subsequent calls to
     // http_connect_handshaker_shutdown() do nothing.
     handshaker->shutdown = true;
   }
   // Invoke callback.
   GRPC_CLOSURE_SCHED(handshaker->on_handshake_done, error);
 }

 // Callback invoked when finished writing HTTP CONNECT request.
 static void on_write_done(void* arg, grpc_error* error) {
   http_connect_handshaker* handshaker =
       static_cast<http_connect_handshaker*>(arg);
   gpr_mu_lock(&handshaker->mu);
   if (error != GRPC_ERROR_NONE || handshaker->shutdown) {
     // If the write failed or we're shutting down, clean up and invoke the
     // callback with the error.
     handshake_failed_locked(handshaker, GRPC_ERROR_REF(error));
     gpr_mu_unlock(&handshaker->mu);
     http_connect_handshaker_unref(handshaker);
   } else {
     // Otherwise, read the response.
     // The read callback inherits our ref to the handshaker.
     grpc_endpoint_read(handshaker->args->endpoint,
                        handshaker->args->read_buffer,
                        &handshaker->response_read_closure);
     gpr_mu_unlock(&handshaker->mu);
   }
 }

 // Callback invoked for reading HTTP CONNECT response.
 static void on_read_done(void* arg, grpc_error* error) {
   http_connect_handshaker* handshaker =
       static_cast<http_connect_handshaker*>(arg);
   gpr_mu_lock(&handshaker->mu);
   if (error != GRPC_ERROR_NONE || handshaker->shutdown) {
     // If the read failed or we're shutting down, clean up and invoke the
     // callback with the error.
     handshake_failed_locked(handshaker, GRPC_ERROR_REF(error));
     goto done;
   }
   // Add buffer to parser.
   for (size_t i = 0; i < handshaker->args->read_buffer->count; ++i) {
     if (GRPC_SLICE_LENGTH(handshaker->args->read_buffer->slices[i]) > 0) {
       size_t body_start_offset = 0;
       error = grpc_http_parser_parse(&handshaker->http_parser,
                                      handshaker->args->read_buffer->slices[i],
                                      &body_start_offset);
       if (error != GRPC_ERROR_NONE) {
         handshake_failed_locked(handshaker, error);
         goto done;
       }
       if (handshaker->http_parser.state == GRPC_HTTP_BODY) {
         // Remove the data we've already read from the read buffer,
         // leaving only the leftover bytes (if any).
         grpc_slice_buffer tmp_buffer;
         grpc_slice_buffer_init(&tmp_buffer);
         if (body_start_offset <
             GRPC_SLICE_LENGTH(handshaker->args->read_buffer->slices[i])) {
           grpc_slice_buffer_add(
               &tmp_buffer,
               grpc_slice_split_tail(&handshaker->args->read_buffer->slices[i],
                                     body_start_offset));
         }
         grpc_slice_buffer_addn(&tmp_buffer,
                                &handshaker->args->read_buffer->slices[i + 1],
                                handshaker->args->read_buffer->count - i - 1);
         grpc_slice_buffer_swap(handshaker->args->read_buffer, &tmp_buffer);
         grpc_slice_buffer_destroy_internal(&tmp_buffer);
         break;
       }
     }
   }
   // If we're not done reading the response, read more data.
   // TODO(roth): In practice, I suspect that the response to a CONNECT
   // request will never include a body, in which case this check is
   // sufficient.  However, the language of RFC-2817 doesn't explicitly
   // forbid the response from including a body.  If there is a body,
   // it's possible that we might have parsed part but not all of the
   // body, in which case this check will cause us to fail to parse the
   // remainder of the body.  If that ever becomes an issue, we may
   // need to fix the HTTP parser to understand when the body is
   // complete (e.g., handling chunked transfer encoding or looking
   // at the Content-Length: header).
   if (handshaker->http_parser.state != GRPC_HTTP_BODY) {
     grpc_slice_buffer_reset_and_unref_internal(handshaker->args->read_buffer);
     grpc_endpoint_read(handshaker->args->endpoint,
                        handshaker->args->read_buffer,
                        &handshaker->response_read_closure);
     gpr_mu_unlock(&handshaker->mu);
     return;
   }
   // Make sure we got a 2xx response.
   if (handshaker->http_response.status < 200 ||
       handshaker->http_response.status >= 300) {
     char* msg;
     gpr_asprintf(&msg, "HTTP proxy returned response code %d",
                  handshaker->http_response.status);
     error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
     gpr_free(msg);
     handshake_failed_locked(handshaker, error);
     goto done;
   }
   // Success.  Invoke handshake-done callback.
   GRPC_CLOSURE_SCHED(handshaker->on_handshake_done, error);
 done:
   // Set shutdown to true so that subsequent calls to
   // http_connect_handshaker_shutdown() do nothing.
   handshaker->shutdown = true;
   gpr_mu_unlock(&handshaker->mu);
   http_connect_handshaker_unref(handshaker);
 }

 //
 // Public handshaker methods
 //

 static void http_connect_handshaker_destroy(grpc_handshaker* handshaker_in) {
   http_connect_handshaker* handshaker =
       reinterpret_cast<http_connect_handshaker*>(handshaker_in);
   http_connect_handshaker_unref(handshaker);
 }

 static void http_connect_handshaker_shutdown(grpc_handshaker* handshaker_in,
                                              grpc_error* why) {
   http_connect_handshaker* handshaker =
       reinterpret_cast<http_connect_handshaker*>(handshaker_in);
   gpr_mu_lock(&handshaker->mu);
   if (!handshaker->shutdown) {
     handshaker->shutdown = true;
     grpc_endpoint_shutdown(handshaker->args->endpoint, GRPC_ERROR_REF(why));
     cleanup_args_for_failure_locked(handshaker);
   }
   gpr_mu_unlock(&handshaker->mu);
   GRPC_ERROR_UNREF(why);
 }

 static void http_connect_handshaker_do_handshake(
     grpc_handshaker* handshaker_in, grpc_tcp_server_acceptor* acceptor,
     grpc_closure* on_handshake_done, grpc_handshaker_args* args) {
   http_connect_handshaker* handshaker =
       reinterpret_cast<http_connect_handshaker*>(handshaker_in);
   // Check for HTTP CONNECT channel arg.
   // If not found, invoke on_handshake_done without doing anything.
   const grpc_arg* arg =
       grpc_channel_args_find(args->args, GRPC_ARG_HTTP_CONNECT_SERVER);
   char* server_name = grpc_channel_arg_get_string(arg);
   if (server_name == nullptr) {
     // Set shutdown to true so that subsequent calls to
     // http_connect_handshaker_shutdown() do nothing.
     gpr_mu_lock(&handshaker->mu);
     handshaker->shutdown = true;
     gpr_mu_unlock(&handshaker->mu);
     GRPC_CLOSURE_SCHED(on_handshake_done, GRPC_ERROR_NONE);
     return;
   }
   // Get headers from channel args.
   arg = grpc_channel_args_find(args->args, GRPC_ARG_HTTP_CONNECT_HEADERS);
   char* arg_header_string = grpc_channel_arg_get_string(arg);
   grpc_http_header* headers = nullptr;
   size_t num_headers = 0;
   char** header_strings = nullptr;
   size_t num_header_strings = 0;
   if (arg_header_string != nullptr) {
     gpr_string_split(arg_header_string, "\n", &header_strings,
                      &num_header_strings);
     headers = static_cast<grpc_http_header*>(
         gpr_malloc(sizeof(grpc_http_header) * num_header_strings));
     for (size_t i = 0; i < num_header_strings; ++i) {
       char* sep = strchr(header_strings[i], ':');
       if (sep == nullptr) {
         gpr_log(GPR_ERROR, "skipping unparseable HTTP CONNECT header: %s",
                 header_strings[i]);
         continue;
       }
       *sep = '\0';
       headers[num_headers].key = header_strings[i];
       headers[num_headers].value = sep + 1;
       ++num_headers;
     }
   }
   // Save state in the handshaker object.
   gpr_mu_lock(&handshaker->mu);
   handshaker->args = args;
   handshaker->on_handshake_done = on_handshake_done;
   // Log connection via proxy.
   char* proxy_name = grpc_endpoint_get_peer(args->endpoint);
   gpr_log(GPR_INFO, "Connecting to server %s via HTTP proxy %s", server_name,
           proxy_name);
   gpr_free(proxy_name);
   // Construct HTTP CONNECT request.
   grpc_httpcli_request request;
   memset(&request, 0, sizeof(request));
   request.host = server_name;
   request.http.method = (char*)"CONNECT";
   request.http.path = server_name;
   request.http.hdrs = headers;
   request.http.hdr_count = num_headers;
   request.handshaker = &grpc_httpcli_plaintext;
   grpc_slice request_slice = grpc_httpcli_format_connect_request(&request);
   grpc_slice_buffer_add(&handshaker->write_buffer, request_slice);
   // Clean up.
   gpr_free(headers);
   for (size_t i = 0; i < num_header_strings; ++i) {
     gpr_free(header_strings[i]);
   }
   gpr_free(header_strings);
   // Take a new ref to be held by the write callback.
   gpr_ref(&handshaker->refcount);
   grpc_endpoint_write(args->endpoint, &handshaker->write_buffer,
                       &handshaker->request_done_closure, nullptr);
   gpr_mu_unlock(&handshaker->mu);
 }

 static const grpc_handshaker_vtable http_connect_handshaker_vtable = {
     http_connect_handshaker_destroy, http_connect_handshaker_shutdown,
     http_connect_handshaker_do_handshake, "http_connect"};

 static grpc_handshaker* grpc_http_connect_handshaker_create() {
   http_connect_handshaker* handshaker =
       static_cast<http_connect_handshaker*>(gpr_malloc(sizeof(*handshaker)));
   memset(handshaker, 0, sizeof(*handshaker));
   grpc_handshaker_init(&http_connect_handshaker_vtable, &handshaker->base);
   gpr_mu_init(&handshaker->mu);
   gpr_ref_init(&handshaker->refcount, 1);
   grpc_slice_buffer_init(&handshaker->write_buffer);
   GRPC_CLOSURE_INIT(&handshaker->request_done_closure, on_write_done,
                     handshaker, grpc_schedule_on_exec_ctx);
   GRPC_CLOSURE_INIT(&handshaker->response_read_closure, on_read_done,
                     handshaker, grpc_schedule_on_exec_ctx);
   grpc_http_parser_init(&handshaker->http_parser, GRPC_HTTP_RESPONSE,
                         &handshaker->http_response);
   return &handshaker->base;
 }

 //
 // handshaker factory
 //

 static void handshaker_factory_add_handshakers(
     grpc_handshaker_factory* factory, const grpc_channel_args* args,
     grpc_pollset_set* interested_parties,
     grpc_handshake_manager* handshake_mgr) {
   grpc_handshake_manager_add(handshake_mgr,
                              grpc_http_connect_handshaker_create());
 }

 static void handshaker_factory_destroy(grpc_handshaker_factory* factory) {}

 static const grpc_handshaker_factory_vtable handshaker_factory_vtable = {
     handshaker_factory_add_handshakers, handshaker_factory_destroy};

 static grpc_handshaker_factory handshaker_factory = {
     &handshaker_factory_vtable};

 void grpc_http_connect_register_handshaker_factory() {
   grpc_handshaker_factory_register(true /* at_start */, HANDSHAKER_CLIENT,
                                    &handshaker_factory);
 }
	/*
	*
	* Copyright 2016 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.
	*
	*/

	#include <grpc/support/port_platform.h>

	#include "src/core/ext/filters/client_channel/http_connect_handshaker.h"

	#include <string.h>

	#include <grpc/slice_buffer.h>
	#include <grpc/support/alloc.h>
	#include <grpc/support/log.h>
	#include <grpc/support/string_util.h>

	#include "src/core/ext/filters/client_channel/client_channel.h"
	#include "src/core/ext/filters/client_channel/resolver_registry.h"
	#include "src/core/lib/channel/channel_args.h"
	#include "src/core/lib/channel/handshaker_registry.h"
	#include "src/core/lib/gpr/env.h"
	#include "src/core/lib/gpr/string.h"
	#include "src/core/lib/http/format_request.h"
	#include "src/core/lib/http/parser.h"
	#include "src/core/lib/slice/slice_internal.h"
	#include "src/core/lib/uri/uri_parser.h"

	typedef struct http_connect_handshaker {
	// Base class. Must be first.
	grpc_handshaker base;

	gpr_refcount refcount;
	gpr_mu mu;

	bool shutdown;
	// Endpoint and read buffer to destroy after a shutdown.
	grpc_endpoint* endpoint_to_destroy;
	grpc_slice_buffer* read_buffer_to_destroy;

	// State saved while performing the handshake.
	grpc_handshaker_args* args;
	grpc_closure* on_handshake_done;

	// Objects for processing the HTTP CONNECT request and response.
	grpc_slice_buffer write_buffer;
	grpc_closure request_done_closure;
	grpc_closure response_read_closure;
	grpc_http_parser http_parser;
	grpc_http_response http_response;
	} http_connect_handshaker;

	// Unref and clean up handshaker.
	static void http_connect_handshaker_unref(http_connect_handshaker* handshaker) {
	if (gpr_unref(&handshaker->refcount)) {
	gpr_mu_destroy(&handshaker->mu);
	if (handshaker->endpoint_to_destroy != nullptr) {
	grpc_endpoint_destroy(handshaker->endpoint_to_destroy);
	}
	if (handshaker->read_buffer_to_destroy != nullptr) {
	grpc_slice_buffer_destroy_internal(handshaker->read_buffer_to_destroy);
	gpr_free(handshaker->read_buffer_to_destroy);
	}
	grpc_slice_buffer_destroy_internal(&handshaker->write_buffer);
	grpc_http_parser_destroy(&handshaker->http_parser);
	grpc_http_response_destroy(&handshaker->http_response);
	gpr_free(handshaker);
	}
	}

	// Set args fields to nullptr, saving the endpoint and read buffer for
	// later destruction.
	static void cleanup_args_for_failure_locked(
	http_connect_handshaker* handshaker) {
	handshaker->endpoint_to_destroy = handshaker->args->endpoint;
	handshaker->args->endpoint = nullptr;
	handshaker->read_buffer_to_destroy = handshaker->args->read_buffer;
	handshaker->args->read_buffer = nullptr;
	grpc_channel_args_destroy(handshaker->args->args);
	handshaker->args->args = nullptr;
	}

	// If the handshake failed or we're shutting down, clean up and invoke the
	// callback with the error.
	static void handshake_failed_locked(http_connect_handshaker* handshaker,
	grpc_error* error) {
	if (error == GRPC_ERROR_NONE) {
	// If we were shut down after an endpoint operation succeeded but
	// before the endpoint callback was invoked, we need to generate our
	// own error.
	error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Handshaker shutdown");
	}
	if (!handshaker->shutdown) {
	// TODO(ctiller): It is currently necessary to shutdown endpoints
	// before destroying them, even if we know that there are no
	// pending read/write callbacks. This should be fixed, at which
	// point this can be removed.
	grpc_endpoint_shutdown(handshaker->args->endpoint, GRPC_ERROR_REF(error));
	// Not shutting down, so the handshake failed. Clean up before
	// invoking the callback.
	cleanup_args_for_failure_locked(handshaker);
	// Set shutdown to true so that subsequent calls to
	// http_connect_handshaker_shutdown() do nothing.
	handshaker->shutdown = true;
	}
	// Invoke callback.
	GRPC_CLOSURE_SCHED(handshaker->on_handshake_done, error);
	}

	// Callback invoked when finished writing HTTP CONNECT request.
	static void on_write_done(void* arg, grpc_error* error) {
	http_connect_handshaker* handshaker =
	static_cast<http_connect_handshaker*>(arg);
	gpr_mu_lock(&handshaker->mu);
	if (error != GRPC_ERROR_NONE \|\| handshaker->shutdown) {
	// If the write failed or we're shutting down, clean up and invoke the
	// callback with the error.
	handshake_failed_locked(handshaker, GRPC_ERROR_REF(error));
	gpr_mu_unlock(&handshaker->mu);
	http_connect_handshaker_unref(handshaker);
	} else {
	// Otherwise, read the response.
	// The read callback inherits our ref to the handshaker.
	grpc_endpoint_read(handshaker->args->endpoint,
	handshaker->args->read_buffer,
	&handshaker->response_read_closure);
	gpr_mu_unlock(&handshaker->mu);
	}
	}

	// Callback invoked for reading HTTP CONNECT response.
	static void on_read_done(void* arg, grpc_error* error) {
	http_connect_handshaker* handshaker =
	static_cast<http_connect_handshaker*>(arg);
	gpr_mu_lock(&handshaker->mu);
	if (error != GRPC_ERROR_NONE \|\| handshaker->shutdown) {
	// If the read failed or we're shutting down, clean up and invoke the
	// callback with the error.
	handshake_failed_locked(handshaker, GRPC_ERROR_REF(error));
	goto done;
	}
	// Add buffer to parser.
	for (size_t i = 0; i < handshaker->args->read_buffer->count; ++i) {
	if (GRPC_SLICE_LENGTH(handshaker->args->read_buffer->slices[i]) > 0) {
	size_t body_start_offset = 0;
	error = grpc_http_parser_parse(&handshaker->http_parser,
	handshaker->args->read_buffer->slices[i],
	&body_start_offset);
	if (error != GRPC_ERROR_NONE) {
	handshake_failed_locked(handshaker, error);
	goto done;
	}
	if (handshaker->http_parser.state == GRPC_HTTP_BODY) {
	// Remove the data we've already read from the read buffer,
	// leaving only the leftover bytes (if any).
	grpc_slice_buffer tmp_buffer;
	grpc_slice_buffer_init(&tmp_buffer);
	if (body_start_offset <
	GRPC_SLICE_LENGTH(handshaker->args->read_buffer->slices[i])) {
	grpc_slice_buffer_add(
	&tmp_buffer,
	grpc_slice_split_tail(&handshaker->args->read_buffer->slices[i],
	body_start_offset));
	}
	grpc_slice_buffer_addn(&tmp_buffer,
	&handshaker->args->read_buffer->slices[i + 1],
	handshaker->args->read_buffer->count - i - 1);
	grpc_slice_buffer_swap(handshaker->args->read_buffer, &tmp_buffer);
	grpc_slice_buffer_destroy_internal(&tmp_buffer);
	break;
	}
	}
	}
	// If we're not done reading the response, read more data.
	// TODO(roth): In practice, I suspect that the response to a CONNECT
	// request will never include a body, in which case this check is
	// sufficient. However, the language of RFC-2817 doesn't explicitly
	// forbid the response from including a body. If there is a body,
	// it's possible that we might have parsed part but not all of the
	// body, in which case this check will cause us to fail to parse the
	// remainder of the body. If that ever becomes an issue, we may
	// need to fix the HTTP parser to understand when the body is
	// complete (e.g., handling chunked transfer encoding or looking
	// at the Content-Length: header).
	if (handshaker->http_parser.state != GRPC_HTTP_BODY) {
	grpc_slice_buffer_reset_and_unref_internal(handshaker->args->read_buffer);
	grpc_endpoint_read(handshaker->args->endpoint,
	handshaker->args->read_buffer,
	&handshaker->response_read_closure);
	gpr_mu_unlock(&handshaker->mu);
	return;
	}
	// Make sure we got a 2xx response.
	if (handshaker->http_response.status < 200 \|\|
	handshaker->http_response.status >= 300) {
	char* msg;
	gpr_asprintf(&msg, "HTTP proxy returned response code %d",
	handshaker->http_response.status);
	error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
	gpr_free(msg);
	handshake_failed_locked(handshaker, error);
	goto done;
	}
	// Success. Invoke handshake-done callback.
	GRPC_CLOSURE_SCHED(handshaker->on_handshake_done, error);
	done:
	// Set shutdown to true so that subsequent calls to
	// http_connect_handshaker_shutdown() do nothing.
	handshaker->shutdown = true;
	gpr_mu_unlock(&handshaker->mu);
	http_connect_handshaker_unref(handshaker);
	}

	//
	// Public handshaker methods
	//

	static void http_connect_handshaker_destroy(grpc_handshaker* handshaker_in) {
	http_connect_handshaker* handshaker =
	reinterpret_cast<http_connect_handshaker*>(handshaker_in);
	http_connect_handshaker_unref(handshaker);
	}

	static void http_connect_handshaker_shutdown(grpc_handshaker* handshaker_in,
	grpc_error* why) {
	http_connect_handshaker* handshaker =
	reinterpret_cast<http_connect_handshaker*>(handshaker_in);
	gpr_mu_lock(&handshaker->mu);
	if (!handshaker->shutdown) {
	handshaker->shutdown = true;
	grpc_endpoint_shutdown(handshaker->args->endpoint, GRPC_ERROR_REF(why));
	cleanup_args_for_failure_locked(handshaker);
	}
	gpr_mu_unlock(&handshaker->mu);
	GRPC_ERROR_UNREF(why);
	}

	static void http_connect_handshaker_do_handshake(
	grpc_handshaker* handshaker_in, grpc_tcp_server_acceptor* acceptor,
	grpc_closure* on_handshake_done, grpc_handshaker_args* args) {
	http_connect_handshaker* handshaker =
	reinterpret_cast<http_connect_handshaker*>(handshaker_in);
	// Check for HTTP CONNECT channel arg.
	// If not found, invoke on_handshake_done without doing anything.
	const grpc_arg* arg =
	grpc_channel_args_find(args->args, GRPC_ARG_HTTP_CONNECT_SERVER);
	char* server_name = grpc_channel_arg_get_string(arg);
	if (server_name == nullptr) {
	// Set shutdown to true so that subsequent calls to
	// http_connect_handshaker_shutdown() do nothing.
	gpr_mu_lock(&handshaker->mu);
	handshaker->shutdown = true;
	gpr_mu_unlock(&handshaker->mu);
	GRPC_CLOSURE_SCHED(on_handshake_done, GRPC_ERROR_NONE);
	return;
	}
	// Get headers from channel args.
	arg = grpc_channel_args_find(args->args, GRPC_ARG_HTTP_CONNECT_HEADERS);
	char* arg_header_string = grpc_channel_arg_get_string(arg);
	grpc_http_header* headers = nullptr;
	size_t num_headers = 0;
	char** header_strings = nullptr;
	size_t num_header_strings = 0;
	if (arg_header_string != nullptr) {
	gpr_string_split(arg_header_string, "\n", &header_strings,
	&num_header_strings);
	headers = static_cast<grpc_http_header*>(
	gpr_malloc(sizeof(grpc_http_header) * num_header_strings));
	for (size_t i = 0; i < num_header_strings; ++i) {
	char* sep = strchr(header_strings[i], ':');
	if (sep == nullptr) {
	gpr_log(GPR_ERROR, "skipping unparseable HTTP CONNECT header: %s",
	header_strings[i]);
	continue;
	}
	*sep = '\0';
	headers[num_headers].key = header_strings[i];
	headers[num_headers].value = sep + 1;
	++num_headers;
	}
	}
	// Save state in the handshaker object.
	gpr_mu_lock(&handshaker->mu);
	handshaker->args = args;
	handshaker->on_handshake_done = on_handshake_done;
	// Log connection via proxy.
	char* proxy_name = grpc_endpoint_get_peer(args->endpoint);
	gpr_log(GPR_INFO, "Connecting to server %s via HTTP proxy %s", server_name,
	proxy_name);
	gpr_free(proxy_name);
	// Construct HTTP CONNECT request.
	grpc_httpcli_request request;
	memset(&request, 0, sizeof(request));
	request.host = server_name;
	request.http.method = (char*)"CONNECT";
	request.http.path = server_name;
	request.http.hdrs = headers;
	request.http.hdr_count = num_headers;
	request.handshaker = &grpc_httpcli_plaintext;
	grpc_slice request_slice = grpc_httpcli_format_connect_request(&request);
	grpc_slice_buffer_add(&handshaker->write_buffer, request_slice);
	// Clean up.
	gpr_free(headers);
	for (size_t i = 0; i < num_header_strings; ++i) {
	gpr_free(header_strings[i]);
	}
	gpr_free(header_strings);
	// Take a new ref to be held by the write callback.
	gpr_ref(&handshaker->refcount);
	grpc_endpoint_write(args->endpoint, &handshaker->write_buffer,
	&handshaker->request_done_closure, nullptr);
	gpr_mu_unlock(&handshaker->mu);
	}

	static const grpc_handshaker_vtable http_connect_handshaker_vtable = {
	http_connect_handshaker_destroy, http_connect_handshaker_shutdown,
	http_connect_handshaker_do_handshake, "http_connect"};

	static grpc_handshaker* grpc_http_connect_handshaker_create() {
	http_connect_handshaker* handshaker =
	static_cast<http_connect_handshaker>(gpr_malloc(sizeof(handshaker)));
	memset(handshaker, 0, sizeof(*handshaker));
	grpc_handshaker_init(&http_connect_handshaker_vtable, &handshaker->base);
	gpr_mu_init(&handshaker->mu);
	gpr_ref_init(&handshaker->refcount, 1);
	grpc_slice_buffer_init(&handshaker->write_buffer);
	GRPC_CLOSURE_INIT(&handshaker->request_done_closure, on_write_done,
	handshaker, grpc_schedule_on_exec_ctx);
	GRPC_CLOSURE_INIT(&handshaker->response_read_closure, on_read_done,
	handshaker, grpc_schedule_on_exec_ctx);
	grpc_http_parser_init(&handshaker->http_parser, GRPC_HTTP_RESPONSE,
	&handshaker->http_response);
	return &handshaker->base;
	}

	//
	// handshaker factory
	//

	static void handshaker_factory_add_handshakers(
	grpc_handshaker_factory* factory, const grpc_channel_args* args,
	grpc_pollset_set* interested_parties,
	grpc_handshake_manager* handshake_mgr) {
	grpc_handshake_manager_add(handshake_mgr,
	grpc_http_connect_handshaker_create());
	}

	static void handshaker_factory_destroy(grpc_handshaker_factory* factory) {}

	static const grpc_handshaker_factory_vtable handshaker_factory_vtable = {
	handshaker_factory_add_handshakers, handshaker_factory_destroy};

	static grpc_handshaker_factory handshaker_factory = {
	&handshaker_factory_vtable};

	void grpc_http_connect_register_handshaker_factory() {
	grpc_handshaker_factory_register(true /* at_start */, HANDSHAKER_CLIENT,
	&handshaker_factory);
	}