text: /*
   *
   * 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 <grpc/grpc.h>
  
  #include <stdlib.h>
  #include <string.h>
  
  #include <grpc/support/alloc.h>
  
  #include "src/core/census/grpc_filter.h"
  #include "src/core/channel/channel_args.h"
  #include "src/core/channel/client_channel.h"
  #include "src/core/channel/compress_filter.h"
  #include "src/core/channel/http_client_filter.h"
  #include "src/core/client_config/resolver_registry.h"
  #include "src/core/iomgr/tcp_client.h"
  #include "src/core/security/auth_filters.h"
  #include "src/core/security/credentials.h"
  #include "src/core/security/secure_transport_setup.h"
  #include "src/core/surface/channel.h"
  #include "src/core/transport/chttp2_transport.h"
  #include "src/core/tsi/transport_security_interface.h"
  
  typedef struct {
    grpc_connector base;
    gpr_refcount refs;
  
    grpc_channel_security_connector *security_connector;
  
    grpc_iomgr_closure *notify;
    grpc_connect_in_args args;
    grpc_connect_out_args *result;
  } connector;
  
  static void connector_ref(grpc_connector *con) {
    connector *c = (connector *)con;
    gpr_ref(&c->refs);
  }
  
  static void connector_unref(grpc_connector *con) {
    connector *c = (connector *)con;
    if (gpr_unref(&c->refs)) {
      gpr_free(c);
    }
  }
  
  static void on_secure_transport_setup_done(void *arg,
                                             grpc_security_status status,
                                             grpc_endpoint *wrapped_endpoint,
                                             grpc_endpoint *secure_endpoint) {
    connector *c = arg;
    grpc_iomgr_closure *notify;
    if (status != GRPC_SECURITY_OK) {
      gpr_log(GPR_ERROR, "Secure transport setup failed with error %d.", status);
      memset(c->result, 0, sizeof(*c->result));
    } else {
      c->result->transport = grpc_create_chttp2_transport(
          c->args.channel_args, secure_endpoint, c->args.metadata_context, 1);
      grpc_chttp2_transport_start_reading(c->result->transport, NULL, 0);
      c->result->filters = gpr_malloc(sizeof(grpc_channel_filter *) * 2);
      c->result->filters[0] = &grpc_http_client_filter;
      c->result->filters[1] = &grpc_client_auth_filter;
      c->result->num_filters = 2;
    }
    notify = c->notify;
    c->notify = NULL;
    grpc_iomgr_add_callback(notify);
  }
  
  static void connected(void *arg, grpc_endpoint *tcp) {
    connector *c = arg;
    grpc_iomgr_closure *notify;
    if (tcp != NULL) {
      grpc_setup_secure_transport(&c->security_connector->base, tcp,
                                  on_secure_transport_setup_done, c);
    } else {
      memset(c->result, 0, sizeof(*c->result));
      notify = c->notify;
      c->notify = NULL;
      grpc_iomgr_add_callback(notify);
    }
  }
  
  static void connector_connect(grpc_connector *con,
                                const grpc_connect_in_args *args,
                                grpc_connect_out_args *result,
                                grpc_iomgr_closure *notify) {
    connector *c = (connector *)con;
    GPR_ASSERT(c->notify == NULL);
    GPR_ASSERT(notify->cb);
    c->notify = notify;
    c->args = *args;
    c->result = result;
    grpc_tcp_client_connect(connected, c, args->interested_parties, args->addr,
                            args->addr_len, args->deadline);
  }
  
  static const grpc_connector_vtable connector_vtable = {
      connector_ref, connector_unref, connector_connect};
  
  typedef struct {
    grpc_subchannel_factory base;
    gpr_refcount refs;
    grpc_mdctx *mdctx;
    grpc_channel_args *merge_args;
    grpc_channel_security_connector *security_connector;
    grpc_channel *master;
  } subchannel_factory;
  
  static void subchannel_factory_ref(grpc_subchannel_factory *scf) {
    subchannel_factory *f = (subchannel_factory *)scf;
    gpr_ref(&f->refs);
  }
  
  static void subchannel_factory_unref(grpc_subchannel_factory *scf) {
    subchannel_factory *f = (subchannel_factory *)scf;
    if (gpr_unref(&f->refs)) {
      GRPC_SECURITY_CONNECTOR_UNREF(&f->security_connector->base,
                                    "subchannel_factory");
      GRPC_CHANNEL_INTERNAL_UNREF(f->master, "subchannel_factory");
      grpc_channel_args_destroy(f->merge_args);
      grpc_mdctx_unref(f->mdctx);
      gpr_free(f);
    }
  }
  
  static grpc_subchannel *subchannel_factory_create_subchannel(
      grpc_subchannel_factory *scf, grpc_subchannel_args *args) {
    subchannel_factory *f = (subchannel_factory *)scf;
    connector *c = gpr_malloc(sizeof(*c));
    grpc_channel_args *final_args =
        grpc_channel_args_merge(args->args, f->merge_args);
    grpc_subchannel *s;
    memset(c, 0, sizeof(*c));
    c->base.vtable = &connector_vtable;
    c->security_connector = f->security_connector;
    gpr_ref_init(&c->refs, 1);
    args->mdctx = f->mdctx;
    args->args = final_args;
    args->master = f->master;
    s = grpc_subchannel_create(&c->base, args);
    grpc_connector_unref(&c->base);
    grpc_channel_args_destroy(final_args);
    return s;
  }
  
  static const grpc_subchannel_factory_vtable subchannel_factory_vtable = {
      subchannel_factory_ref, subchannel_factory_unref,
      subchannel_factory_create_subchannel};
  
  /* Create a secure client channel:
     Asynchronously: - resolve target
                     - connect to it (trying alternatives as presented)
                     - perform handshakes */
  grpc_channel *grpc_secure_channel_create(grpc_credentials *creds,
                                           const char *target,
                                           const grpc_channel_args *args,
                                           void *reserved) {
    grpc_channel *channel;
    grpc_arg connector_arg;
    grpc_channel_args *args_copy;
    grpc_channel_args *new_args_from_connector;
    grpc_channel_security_connector *connector;
    grpc_mdctx *mdctx;
    grpc_resolver *resolver;
    subchannel_factory *f;
  #define MAX_FILTERS 3
    const grpc_channel_filter *filters[MAX_FILTERS];
    int n = 0;
  
    GPR_ASSERT(reserved == NULL);
    if (grpc_find_security_connector_in_args(args) != NULL) {
      gpr_log(GPR_ERROR, "Cannot set security context in channel args.");
      return grpc_lame_client_channel_create(
          target, GRPC_STATUS_INVALID_ARGUMENT,
          "Security connector exists in channel args.");
    }
  
    if (grpc_credentials_create_security_connector(
            creds, target, args, NULL, &connector, &new_args_from_connector) !=
        GRPC_SECURITY_OK) {
      return grpc_lame_client_channel_create(
          target, GRPC_STATUS_INVALID_ARGUMENT,
          "Failed to create security connector.");
    }
    mdctx = grpc_mdctx_create();
  
    connector_arg = grpc_security_connector_to_arg(&connector->base);
    args_copy = grpc_channel_args_copy_and_add(
        new_args_from_connector != NULL ? new_args_from_connector : args,
        &connector_arg, 1);
    if (grpc_channel_args_is_census_enabled(args)) {
      filters[n++] = &grpc_client_census_filter;
    }
    filters[n++] = &grpc_compress_filter;
    filters[n++] = &grpc_client_channel_filter;
    GPR_ASSERT(n <= MAX_FILTERS);
  
    channel =
        grpc_channel_create_from_filters(target, filters, n, args_copy, mdctx, 1);
  
    f = gpr_malloc(sizeof(*f));
    f->base.vtable = &subchannel_factory_vtable;
    gpr_ref_init(&f->refs, 1);
    grpc_mdctx_ref(mdctx);
    f->mdctx = mdctx;
    GRPC_SECURITY_CONNECTOR_REF(&connector->base, "subchannel_factory");
    f->security_connector = connector;
    f->merge_args = grpc_channel_args_copy(args_copy);
    f->master = channel;
    GRPC_CHANNEL_INTERNAL_REF(channel, "subchannel_factory");
    resolver = grpc_resolver_create(target, &f->base);
    if (!resolver) {
      return NULL;
    }
  
    grpc_client_channel_set_resolver(grpc_channel_get_channel_stack(channel),
                                     resolver);
    GRPC_RESOLVER_UNREF(resolver, "create");
    grpc_subchannel_factory_unref(&f->base);
    GRPC_SECURITY_CONNECTOR_UNREF(&connector->base, "channel_create");
  
    grpc_channel_args_destroy(args_copy);
    if (new_args_from_connector != NULL) {
      grpc_channel_args_destroy(new_args_from_connector);
    }
  
    return channel;
  }
  