text: /*
   *
   * 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.
   *
   */
  
  #include <grpc/support/port_platform.h>
  
  #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h"
  
  #include <string.h>
  
  #include "absl/container/inlined_vector.h"
  
  #include <grpc/grpc_security.h>
  #include <grpc/support/alloc.h>
  #include <grpc/support/string_util.h>
  
  #include "src/core/ext/filters/client_channel/client_channel.h"
  #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_balancer_addresses.h"
  #include "src/core/ext/filters/client_channel/server_address.h"
  #include "src/core/lib/channel/channel_args.h"
  #include "src/core/lib/gpr/string.h"
  #include "src/core/lib/iomgr/sockaddr_utils.h"
  #include "src/core/lib/security/credentials/credentials.h"
  #include "src/core/lib/slice/slice_internal.h"
  
  namespace grpc_core {
  
  grpc_channel_args* ModifyGrpclbBalancerChannelArgs(grpc_channel_args* args) {
    absl::InlinedVector<const char*, 1> args_to_remove;
    absl::InlinedVector<grpc_arg, 1> args_to_add;
    // Substitute the channel credentials with a version without call
    // credentials: the load balancer is not necessarily trusted to handle
    // bearer token credentials.
    grpc_channel_credentials* channel_credentials =
        grpc_channel_credentials_find_in_args(args);
    RefCountedPtr<grpc_channel_credentials> creds_sans_call_creds;
    if (channel_credentials != nullptr) {
      creds_sans_call_creds =
          channel_credentials->duplicate_without_call_credentials();
      GPR_ASSERT(creds_sans_call_creds != nullptr);
      args_to_remove.emplace_back(GRPC_ARG_CHANNEL_CREDENTIALS);
      args_to_add.emplace_back(
          grpc_channel_credentials_to_arg(creds_sans_call_creds.get()));
    }
    grpc_channel_args* result = grpc_channel_args_copy_and_add_and_remove(
        args, args_to_remove.data(), args_to_remove.size(), args_to_add.data(),
        args_to_add.size());
    // Clean up.
    grpc_channel_args_destroy(args);
    return result;
  }
  
  grpc_channel* CreateGrpclbBalancerChannel(const char* target_uri,
                                            const grpc_channel_args& args) {
    grpc_channel_credentials* creds =
        grpc_channel_credentials_find_in_args(&args);
    if (creds == nullptr) {
      // Build with security but parent channel is insecure.
      return grpc_insecure_channel_create(target_uri, &args, nullptr);
    }
    const char* arg_to_remove = GRPC_ARG_CHANNEL_CREDENTIALS;
    grpc_channel_args* new_args =
        grpc_channel_args_copy_and_remove(&args, &arg_to_remove, 1);
    grpc_channel* channel =
        grpc_secure_channel_create(creds, target_uri, new_args, nullptr);
    grpc_channel_args_destroy(new_args);
    return channel;
  }
  
  }  // namespace grpc_core
  