src/core/lib/iomgr/tcp_client_posix.c - third_party/grpc - Git at Google

 /*
  *
  * Copyright 2015, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */

 #include "src/core/lib/iomgr/port.h"

 #ifdef GRPC_POSIX_SOCKET

 #include "src/core/lib/iomgr/tcp_client_posix.h"

 #include <errno.h>
 #include <netinet/in.h>
 #include <string.h>
 #include <unistd.h>

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

 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/iomgr_posix.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/socket_mutator.h"
 #include "src/core/lib/iomgr/socket_utils_posix.h"
 #include "src/core/lib/iomgr/tcp_posix.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
 #include "src/core/lib/support/string.h"

 extern grpc_tracer_flag grpc_tcp_trace;

 typedef struct {
   gpr_mu mu;
   grpc_fd *fd;
   gpr_timespec deadline;
   grpc_timer alarm;
   grpc_closure on_alarm;
   int refs;
   grpc_closure write_closure;
   grpc_pollset_set *interested_parties;
   char *addr_str;
   grpc_endpoint **ep;
   grpc_closure *closure;
   grpc_channel_args *channel_args;
 } async_connect;

 static grpc_error *prepare_socket(const grpc_resolved_address *addr, int fd,
                                   const grpc_channel_args *channel_args) {
   grpc_error *err = GRPC_ERROR_NONE;

   GPR_ASSERT(fd >= 0);

   err = grpc_set_socket_nonblocking(fd, 1);
   if (err != GRPC_ERROR_NONE) goto error;
   err = grpc_set_socket_cloexec(fd, 1);
   if (err != GRPC_ERROR_NONE) goto error;
   if (!grpc_is_unix_socket(addr)) {
     err = grpc_set_socket_low_latency(fd, 1);
     if (err != GRPC_ERROR_NONE) goto error;
   }
   err = grpc_set_socket_no_sigpipe_if_possible(fd);
   if (err != GRPC_ERROR_NONE) goto error;
   if (channel_args) {
     for (size_t i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_SOCKET_MUTATOR)) {
         GPR_ASSERT(channel_args->args[i].type == GRPC_ARG_POINTER);
         grpc_socket_mutator *mutator = channel_args->args[i].value.pointer.p;
         err = grpc_set_socket_with_mutator(fd, mutator);
         if (err != GRPC_ERROR_NONE) goto error;
       }
     }
   }
   goto done;

 error:
   if (fd >= 0) {
     close(fd);
   }
 done:
   return err;
 }

 static void tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   int done;
   async_connect *ac = acp;
   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_alarm: error=%s", ac->addr_str,
             str);
   }
   gpr_mu_lock(&ac->mu);
   if (ac->fd != NULL) {
     grpc_fd_shutdown(exec_ctx, ac->fd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                                            "connect() timed out"));
   }
   done = (--ac->refs == 0);
   gpr_mu_unlock(&ac->mu);
   if (done) {
     gpr_mu_destroy(&ac->mu);
     gpr_free(ac->addr_str);
     grpc_channel_args_destroy(exec_ctx, ac->channel_args);
     gpr_free(ac);
   }
 }

 grpc_endpoint *grpc_tcp_client_create_from_fd(
     grpc_exec_ctx *exec_ctx, grpc_fd *fd, const grpc_channel_args *channel_args,
     const char *addr_str) {
   return grpc_tcp_create(exec_ctx, fd, channel_args, addr_str);
 }

 static void on_writable(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   async_connect *ac = acp;
   int so_error = 0;
   socklen_t so_error_size;
   int err;
   int done;
   grpc_endpoint **ep = ac->ep;
   grpc_closure *closure = ac->closure;
   grpc_fd *fd;

   GRPC_ERROR_REF(error);

   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_writable: error=%s",
             ac->addr_str, str);
   }

   gpr_mu_lock(&ac->mu);
   GPR_ASSERT(ac->fd);
   fd = ac->fd;
   ac->fd = NULL;
   gpr_mu_unlock(&ac->mu);

   grpc_timer_cancel(exec_ctx, &ac->alarm);

   gpr_mu_lock(&ac->mu);
   if (error != GRPC_ERROR_NONE) {
     error =
         grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
                            grpc_slice_from_static_string("Timeout occurred"));
     goto finish;
   }

   do {
     so_error_size = sizeof(so_error);
     err = getsockopt(grpc_fd_wrapped_fd(fd), SOL_SOCKET, SO_ERROR, &so_error,
                      &so_error_size);
   } while (err < 0 && errno == EINTR);
   if (err < 0) {
     error = GRPC_OS_ERROR(errno, "getsockopt");
     goto finish;
   }

   switch (so_error) {
     case 0:
       grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
       *ep = grpc_tcp_client_create_from_fd(exec_ctx, fd, ac->channel_args,
                                            ac->addr_str);
       fd = NULL;
       break;
     case ENOBUFS:
       /* We will get one of these errors if we have run out of
          memory in the kernel for the data structures allocated
          when you connect a socket.  If this happens it is very
          likely that if we wait a little bit then try again the
          connection will work (since other programs or this
          program will close their network connections and free up
          memory).  This does _not_ indicate that there is anything
          wrong with the server we are connecting to, this is a
          local problem.

          If you are looking at this code, then chances are that
          your program or another program on the same computer
          opened too many network connections.  The "easy" fix:
          don't do that! */
       gpr_log(GPR_ERROR, "kernel out of buffers");
       gpr_mu_unlock(&ac->mu);
       grpc_fd_notify_on_write(exec_ctx, fd, &ac->write_closure);
       return;
     case ECONNREFUSED:
       /* This error shouldn't happen for anything other than connect(). */
       error = GRPC_OS_ERROR(so_error, "connect");
       break;
     default:
       /* We don't really know which syscall triggered the problem here,
          so punt by reporting getsockopt(). */
       error = GRPC_OS_ERROR(so_error, "getsockopt(SO_ERROR)");
       break;
   }

 finish:
   if (fd != NULL) {
     grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
     grpc_fd_orphan(exec_ctx, fd, NULL, NULL, "tcp_client_orphan");
     fd = NULL;
   }
   done = (--ac->refs == 0);
   gpr_mu_unlock(&ac->mu);
   if (error != GRPC_ERROR_NONE) {
     char *error_descr;
     grpc_slice str;
     bool ret = grpc_error_get_str(error, GRPC_ERROR_STR_DESCRIPTION, &str);
     GPR_ASSERT(ret);
     char *desc = grpc_slice_to_c_string(str);
     gpr_asprintf(&error_descr, "Failed to connect to remote host: %s", desc);
     error = grpc_error_set_str(error, GRPC_ERROR_STR_DESCRIPTION,
                                grpc_slice_from_copied_string(error_descr));
     gpr_free(error_descr);
     gpr_free(desc);
     error = grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS,
                                grpc_slice_from_copied_string(ac->addr_str));
   }
   if (done) {
     gpr_mu_destroy(&ac->mu);
     gpr_free(ac->addr_str);
     grpc_channel_args_destroy(exec_ctx, ac->channel_args);
     gpr_free(ac);
   }
   grpc_closure_sched(exec_ctx, closure, error);
 }

 static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
                                     grpc_closure *closure, grpc_endpoint **ep,
                                     grpc_pollset_set *interested_parties,
                                     const grpc_channel_args *channel_args,
                                     const grpc_resolved_address *addr,
                                     gpr_timespec deadline) {
   int fd;
   grpc_dualstack_mode dsmode;
   int err;
   async_connect *ac;
   grpc_resolved_address addr6_v4mapped;
   grpc_resolved_address addr4_copy;
   grpc_fd *fdobj;
   char *name;
   char *addr_str;
   grpc_error *error;

   *ep = NULL;

   /* Use dualstack sockets where available. */
   if (grpc_sockaddr_to_v4mapped(addr, &addr6_v4mapped)) {
     addr = &addr6_v4mapped;
   }

   error = grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, &dsmode, &fd);
   if (error != GRPC_ERROR_NONE) {
     grpc_closure_sched(exec_ctx, closure, error);
     return;
   }
   if (dsmode == GRPC_DSMODE_IPV4) {
     /* If we got an AF_INET socket, map the address back to IPv4. */
     GPR_ASSERT(grpc_sockaddr_is_v4mapped(addr, &addr4_copy));
     addr = &addr4_copy;
   }
   if ((error = prepare_socket(addr, fd, channel_args)) != GRPC_ERROR_NONE) {
     grpc_closure_sched(exec_ctx, closure, error);
     return;
   }

   do {
     GPR_ASSERT(addr->len < ~(socklen_t)0);
     err =
         connect(fd, (const struct sockaddr *)addr->addr, (socklen_t)addr->len);
     if (err >= 0) {
       // Note(rudominer) This is a temporary hack designed to work around two
       // bugs:
       // (1) Fuchsia's implementation of connect() does not honor O_NONBLOCK
       // (2) gRPC with TLS does not complete the TLS handshake if the branch
       //     "if (err >= 0)" below is taken.
       err = -1;
       errno = EINPROGRESS;
     }
   } while (err < 0 && errno == EINTR);

   addr_str = grpc_sockaddr_to_uri(addr);
   gpr_asprintf(&name, "tcp-client:%s", addr_str);

   fdobj = grpc_fd_create(fd, name);

   if (err >= 0) {
     *ep =
         grpc_tcp_client_create_from_fd(exec_ctx, fdobj, channel_args, addr_str);
     grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
     goto done;
   }

   if (errno != EWOULDBLOCK && errno != EINPROGRESS) {
     grpc_fd_orphan(exec_ctx, fdobj, NULL, NULL, "tcp_client_connect_error");
     grpc_closure_sched(exec_ctx, closure, GRPC_OS_ERROR(errno, "connect"));
     goto done;
   }

   grpc_pollset_set_add_fd(exec_ctx, interested_parties, fdobj);

   ac = gpr_malloc(sizeof(async_connect));
   ac->closure = closure;
   ac->ep = ep;
   ac->fd = fdobj;
   ac->interested_parties = interested_parties;
   ac->addr_str = addr_str;
   addr_str = NULL;
   gpr_mu_init(&ac->mu);
   ac->refs = 2;
   grpc_closure_init(&ac->write_closure, on_writable, ac,
                     grpc_schedule_on_exec_ctx);
   ac->channel_args = grpc_channel_args_copy(channel_args);

   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: asynchronously connecting fd %p",
             ac->addr_str, fdobj);
   }

   gpr_mu_lock(&ac->mu);
   grpc_closure_init(&ac->on_alarm, tc_on_alarm, ac, grpc_schedule_on_exec_ctx);
   grpc_timer_init(exec_ctx, &ac->alarm,
                   gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
                   &ac->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_fd_notify_on_write(exec_ctx, ac->fd, &ac->write_closure);
   gpr_mu_unlock(&ac->mu);

 done:
   gpr_free(name);
   gpr_free(addr_str);
 }

 // overridden by api_fuzzer.c
 void (*grpc_tcp_client_connect_impl)(
     grpc_exec_ctx *exec_ctx, grpc_closure *closure, grpc_endpoint **ep,
     grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
     const grpc_resolved_address *addr,
     gpr_timespec deadline) = tcp_client_connect_impl;

 void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                              grpc_endpoint **ep,
                              grpc_pollset_set *interested_parties,
                              const grpc_channel_args *channel_args,
                              const grpc_resolved_address *addr,
                              gpr_timespec deadline) {
   grpc_tcp_client_connect_impl(exec_ctx, closure, ep, interested_parties,
                                channel_args, addr, deadline);
 }

 #endif
	/*
	*
	* Copyright 2015, Google Inc.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	*/

	#include "src/core/lib/iomgr/port.h"

	#ifdef GRPC_POSIX_SOCKET

	#include "src/core/lib/iomgr/tcp_client_posix.h"

	#include <errno.h>
	#include <netinet/in.h>
	#include <string.h>
	#include <unistd.h>

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

	#include "src/core/lib/channel/channel_args.h"
	#include "src/core/lib/iomgr/ev_posix.h"
	#include "src/core/lib/iomgr/iomgr_posix.h"
	#include "src/core/lib/iomgr/sockaddr_utils.h"
	#include "src/core/lib/iomgr/socket_mutator.h"
	#include "src/core/lib/iomgr/socket_utils_posix.h"
	#include "src/core/lib/iomgr/tcp_posix.h"
	#include "src/core/lib/iomgr/timer.h"
	#include "src/core/lib/iomgr/unix_sockets_posix.h"
	#include "src/core/lib/support/string.h"

	extern grpc_tracer_flag grpc_tcp_trace;

	typedef struct {
	gpr_mu mu;
	grpc_fd *fd;
	gpr_timespec deadline;
	grpc_timer alarm;
	grpc_closure on_alarm;
	int refs;
	grpc_closure write_closure;
	grpc_pollset_set *interested_parties;
	char *addr_str;
	grpc_endpoint **ep;
	grpc_closure *closure;
	grpc_channel_args *channel_args;
	} async_connect;

	static grpc_error prepare_socket(const grpc_resolved_address addr, int fd,
	const grpc_channel_args *channel_args) {
	grpc_error *err = GRPC_ERROR_NONE;

	GPR_ASSERT(fd >= 0);

	err = grpc_set_socket_nonblocking(fd, 1);
	if (err != GRPC_ERROR_NONE) goto error;
	err = grpc_set_socket_cloexec(fd, 1);
	if (err != GRPC_ERROR_NONE) goto error;
	if (!grpc_is_unix_socket(addr)) {
	err = grpc_set_socket_low_latency(fd, 1);
	if (err != GRPC_ERROR_NONE) goto error;
	}
	err = grpc_set_socket_no_sigpipe_if_possible(fd);
	if (err != GRPC_ERROR_NONE) goto error;
	if (channel_args) {
	for (size_t i = 0; i < channel_args->num_args; i++) {
	if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_SOCKET_MUTATOR)) {
	GPR_ASSERT(channel_args->args[i].type == GRPC_ARG_POINTER);
	grpc_socket_mutator *mutator = channel_args->args[i].value.pointer.p;
	err = grpc_set_socket_with_mutator(fd, mutator);
	if (err != GRPC_ERROR_NONE) goto error;
	}
	}
	}
	goto done;

	error:
	if (fd >= 0) {
	close(fd);
	}
	done:
	return err;
	}

	static void tc_on_alarm(grpc_exec_ctx exec_ctx, void acp, grpc_error *error) {
	int done;
	async_connect *ac = acp;
	if (GRPC_TRACER_ON(grpc_tcp_trace)) {
	const char *str = grpc_error_string(error);
	gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_alarm: error=%s", ac->addr_str,
	str);
	}
	gpr_mu_lock(&ac->mu);
	if (ac->fd != NULL) {
	grpc_fd_shutdown(exec_ctx, ac->fd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
	"connect() timed out"));
	}
	done = (--ac->refs == 0);
	gpr_mu_unlock(&ac->mu);
	if (done) {
	gpr_mu_destroy(&ac->mu);
	gpr_free(ac->addr_str);
	grpc_channel_args_destroy(exec_ctx, ac->channel_args);
	gpr_free(ac);
	}
	}

	grpc_endpoint *grpc_tcp_client_create_from_fd(
	grpc_exec_ctx exec_ctx, grpc_fd fd, const grpc_channel_args *channel_args,
	const char *addr_str) {
	return grpc_tcp_create(exec_ctx, fd, channel_args, addr_str);
	}

	static void on_writable(grpc_exec_ctx exec_ctx, void acp, grpc_error *error) {
	async_connect *ac = acp;
	int so_error = 0;
	socklen_t so_error_size;
	int err;
	int done;
	grpc_endpoint **ep = ac->ep;
	grpc_closure *closure = ac->closure;
	grpc_fd *fd;

	GRPC_ERROR_REF(error);

	if (GRPC_TRACER_ON(grpc_tcp_trace)) {
	const char *str = grpc_error_string(error);
	gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_writable: error=%s",
	ac->addr_str, str);
	}

	gpr_mu_lock(&ac->mu);
	GPR_ASSERT(ac->fd);
	fd = ac->fd;
	ac->fd = NULL;
	gpr_mu_unlock(&ac->mu);

	grpc_timer_cancel(exec_ctx, &ac->alarm);

	gpr_mu_lock(&ac->mu);
	if (error != GRPC_ERROR_NONE) {
	error =
	grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
	grpc_slice_from_static_string("Timeout occurred"));
	goto finish;
	}

	do {
	so_error_size = sizeof(so_error);
	err = getsockopt(grpc_fd_wrapped_fd(fd), SOL_SOCKET, SO_ERROR, &so_error,
	&so_error_size);
	} while (err < 0 && errno == EINTR);
	if (err < 0) {
	error = GRPC_OS_ERROR(errno, "getsockopt");
	goto finish;
	}

	switch (so_error) {
	case 0:
	grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
	*ep = grpc_tcp_client_create_from_fd(exec_ctx, fd, ac->channel_args,
	ac->addr_str);
	fd = NULL;
	break;
	case ENOBUFS:
	/* We will get one of these errors if we have run out of
	memory in the kernel for the data structures allocated
	when you connect a socket. If this happens it is very
	likely that if we wait a little bit then try again the
	connection will work (since other programs or this
	program will close their network connections and free up
	memory). This does _not_ indicate that there is anything
	wrong with the server we are connecting to, this is a
	local problem.

	If you are looking at this code, then chances are that
	your program or another program on the same computer
	opened too many network connections. The "easy" fix:
	don't do that! */
	gpr_log(GPR_ERROR, "kernel out of buffers");
	gpr_mu_unlock(&ac->mu);
	grpc_fd_notify_on_write(exec_ctx, fd, &ac->write_closure);
	return;
	case ECONNREFUSED:
	/* This error shouldn't happen for anything other than connect(). */
	error = GRPC_OS_ERROR(so_error, "connect");
	break;
	default:
	/* We don't really know which syscall triggered the problem here,
	so punt by reporting getsockopt(). */
	error = GRPC_OS_ERROR(so_error, "getsockopt(SO_ERROR)");
	break;
	}

	finish:
	if (fd != NULL) {
	grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
	grpc_fd_orphan(exec_ctx, fd, NULL, NULL, "tcp_client_orphan");
	fd = NULL;
	}
	done = (--ac->refs == 0);
	gpr_mu_unlock(&ac->mu);
	if (error != GRPC_ERROR_NONE) {
	char *error_descr;
	grpc_slice str;
	bool ret = grpc_error_get_str(error, GRPC_ERROR_STR_DESCRIPTION, &str);
	GPR_ASSERT(ret);
	char *desc = grpc_slice_to_c_string(str);
	gpr_asprintf(&error_descr, "Failed to connect to remote host: %s", desc);
	error = grpc_error_set_str(error, GRPC_ERROR_STR_DESCRIPTION,
	grpc_slice_from_copied_string(error_descr));
	gpr_free(error_descr);
	gpr_free(desc);
	error = grpc_error_set_str(error, GRPC_ERROR_STR_TARGET_ADDRESS,
	grpc_slice_from_copied_string(ac->addr_str));
	}
	if (done) {
	gpr_mu_destroy(&ac->mu);
	gpr_free(ac->addr_str);
	grpc_channel_args_destroy(exec_ctx, ac->channel_args);
	gpr_free(ac);
	}
	grpc_closure_sched(exec_ctx, closure, error);
	}

	static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
	grpc_closure closure, grpc_endpoint *ep,
	grpc_pollset_set *interested_parties,
	const grpc_channel_args *channel_args,
	const grpc_resolved_address *addr,
	gpr_timespec deadline) {
	int fd;
	grpc_dualstack_mode dsmode;
	int err;
	async_connect *ac;
	grpc_resolved_address addr6_v4mapped;
	grpc_resolved_address addr4_copy;
	grpc_fd *fdobj;
	char *name;
	char *addr_str;
	grpc_error *error;

	*ep = NULL;

	/* Use dualstack sockets where available. */
	if (grpc_sockaddr_to_v4mapped(addr, &addr6_v4mapped)) {
	addr = &addr6_v4mapped;
	}

	error = grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, &dsmode, &fd);
	if (error != GRPC_ERROR_NONE) {
	grpc_closure_sched(exec_ctx, closure, error);
	return;
	}
	if (dsmode == GRPC_DSMODE_IPV4) {
	/* If we got an AF_INET socket, map the address back to IPv4. */
	GPR_ASSERT(grpc_sockaddr_is_v4mapped(addr, &addr4_copy));
	addr = &addr4_copy;
	}
	if ((error = prepare_socket(addr, fd, channel_args)) != GRPC_ERROR_NONE) {
	grpc_closure_sched(exec_ctx, closure, error);
	return;
	}

	do {
	GPR_ASSERT(addr->len < ~(socklen_t)0);
	err =
	connect(fd, (const struct sockaddr *)addr->addr, (socklen_t)addr->len);
	if (err >= 0) {
	// Note(rudominer) This is a temporary hack designed to work around two
	// bugs:
	// (1) Fuchsia's implementation of connect() does not honor O_NONBLOCK
	// (2) gRPC with TLS does not complete the TLS handshake if the branch
	// "if (err >= 0)" below is taken.
	err = -1;
	errno = EINPROGRESS;
	}
	} while (err < 0 && errno == EINTR);

	addr_str = grpc_sockaddr_to_uri(addr);
	gpr_asprintf(&name, "tcp-client:%s", addr_str);

	fdobj = grpc_fd_create(fd, name);

	if (err >= 0) {
	*ep =
	grpc_tcp_client_create_from_fd(exec_ctx, fdobj, channel_args, addr_str);
	grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
	goto done;
	}

	if (errno != EWOULDBLOCK && errno != EINPROGRESS) {
	grpc_fd_orphan(exec_ctx, fdobj, NULL, NULL, "tcp_client_connect_error");
	grpc_closure_sched(exec_ctx, closure, GRPC_OS_ERROR(errno, "connect"));
	goto done;
	}

	grpc_pollset_set_add_fd(exec_ctx, interested_parties, fdobj);

	ac = gpr_malloc(sizeof(async_connect));
	ac->closure = closure;
	ac->ep = ep;
	ac->fd = fdobj;
	ac->interested_parties = interested_parties;
	ac->addr_str = addr_str;
	addr_str = NULL;
	gpr_mu_init(&ac->mu);
	ac->refs = 2;
	grpc_closure_init(&ac->write_closure, on_writable, ac,
	grpc_schedule_on_exec_ctx);
	ac->channel_args = grpc_channel_args_copy(channel_args);

	if (GRPC_TRACER_ON(grpc_tcp_trace)) {
	gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: asynchronously connecting fd %p",
	ac->addr_str, fdobj);
	}

	gpr_mu_lock(&ac->mu);
	grpc_closure_init(&ac->on_alarm, tc_on_alarm, ac, grpc_schedule_on_exec_ctx);
	grpc_timer_init(exec_ctx, &ac->alarm,
	gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
	&ac->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
	grpc_fd_notify_on_write(exec_ctx, ac->fd, &ac->write_closure);
	gpr_mu_unlock(&ac->mu);

	done:
	gpr_free(name);
	gpr_free(addr_str);
	}

	// overridden by api_fuzzer.c
	void (*grpc_tcp_client_connect_impl)(
	grpc_exec_ctx exec_ctx, grpc_closure closure, grpc_endpoint **ep,
	grpc_pollset_set interested_parties, const grpc_channel_args channel_args,
	const grpc_resolved_address *addr,
	gpr_timespec deadline) = tcp_client_connect_impl;

	void grpc_tcp_client_connect(grpc_exec_ctx exec_ctx, grpc_closure closure,
	grpc_endpoint **ep,
	grpc_pollset_set *interested_parties,
	const grpc_channel_args *channel_args,
	const grpc_resolved_address *addr,
	gpr_timespec deadline) {
	grpc_tcp_client_connect_impl(exec_ctx, closure, ep, interested_parties,
	channel_args, addr, deadline);
	}

	#endif