Guard headers tool.
diff --git a/examples/pubsub/publisher.h b/examples/pubsub/publisher.h
index 2d64a2a..c90406f 100644
--- a/examples/pubsub/publisher.h
+++ b/examples/pubsub/publisher.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_EXAMPLES_PUBSUB_PUBLISHER_H_
-#define __GRPCPP_EXAMPLES_PUBSUB_PUBLISHER_H_
+#ifndef GRPC_EXAMPLES_PUBSUB_PUBLISHER_H
+#define GRPC_EXAMPLES_PUBSUB_PUBLISHER_H
 
 #include <grpc++/channel_interface.h>
 #include <grpc++/status.h>
@@ -64,4 +64,4 @@
 }  // namespace examples
 }  // namespace grpc
 
-#endif  // __GRPCPP_EXAMPLES_PUBSUB_PUBLISHER_H_
+#endif  // GRPC_EXAMPLES_PUBSUB_PUBLISHER_H
diff --git a/examples/pubsub/subscriber.h b/examples/pubsub/subscriber.h
index a973cd7..c587c01 100644
--- a/examples/pubsub/subscriber.h
+++ b/examples/pubsub/subscriber.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_EXAMPLES_PUBSUB_SUBSCRIBER_H_
-#define __GRPCPP_EXAMPLES_PUBSUB_SUBSCRIBER_H_
+#ifndef GRPC_EXAMPLES_PUBSUB_SUBSCRIBER_H
+#define GRPC_EXAMPLES_PUBSUB_SUBSCRIBER_H
 
 #include <grpc++/channel_interface.h>
 #include <grpc++/status.h>
@@ -65,4 +65,4 @@
 }  // namespace examples
 }  // namespace grpc
 
-#endif  // __GRPCPP_EXAMPLES_PUBSUB_SUBSCRIBER_H_
+#endif  // GRPC_EXAMPLES_PUBSUB_SUBSCRIBER_H
diff --git a/include/grpc++/async_unary_call.h b/include/grpc++/async_unary_call.h
index ccd0806..71b7d3f 100644
--- a/include/grpc++/async_unary_call.h
+++ b/include/grpc++/async_unary_call.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_ASYNC_UNARY_CALL_H__
-#define __GRPCPP_ASYNC_UNARY_CALL_H__
+#ifndef GRPCXX_ASYNC_UNARY_CALL_H
+#define GRPCXX_ASYNC_UNARY_CALL_H
 
 #include <grpc++/channel_interface.h>
 #include <grpc++/client_context.h>
@@ -138,4 +138,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_ASYNC_UNARY_CALL_H__
+#endif  // GRPCXX_ASYNC_UNARY_CALL_H
diff --git a/include/grpc++/channel_arguments.h b/include/grpc++/channel_arguments.h
index 75c3cf4..ad96ef1 100644
--- a/include/grpc++/channel_arguments.h
+++ b/include/grpc++/channel_arguments.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CHANNEL_ARGUMENTS_H_
-#define __GRPCPP_CHANNEL_ARGUMENTS_H_
+#ifndef GRPCXX_CHANNEL_ARGUMENTS_H
+#define GRPCXX_CHANNEL_ARGUMENTS_H
 
 #include <vector>
 #include <list>
@@ -82,4 +82,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CHANNEL_ARGUMENTS_H_
+#endif  // GRPCXX_CHANNEL_ARGUMENTS_H
diff --git a/include/grpc++/channel_interface.h b/include/grpc++/channel_interface.h
index 890fd04..77d1363 100644
--- a/include/grpc++/channel_interface.h
+++ b/include/grpc++/channel_interface.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CHANNEL_INTERFACE_H__
-#define __GRPCPP_CHANNEL_INTERFACE_H__
+#ifndef GRPCXX_CHANNEL_INTERFACE_H
+#define GRPCXX_CHANNEL_INTERFACE_H
 
 #include <grpc++/status.h>
 #include <grpc++/impl/call.h>
@@ -63,4 +63,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CHANNEL_INTERFACE_H__
+#endif  // GRPCXX_CHANNEL_INTERFACE_H
diff --git a/include/grpc++/client_context.h b/include/grpc++/client_context.h
index c5a213e..87e5e9a 100644
--- a/include/grpc++/client_context.h
+++ b/include/grpc++/client_context.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CLIENT_CONTEXT_H__
-#define __GRPCPP_CLIENT_CONTEXT_H__
+#ifndef GRPCXX_CLIENT_CONTEXT_H
+#define GRPCXX_CLIENT_CONTEXT_H
 
 #include <chrono>
 #include <map>
@@ -151,4 +151,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CLIENT_CONTEXT_H__
+#endif  // GRPCXX_CLIENT_CONTEXT_H
diff --git a/include/grpc++/completion_queue.h b/include/grpc++/completion_queue.h
index 0075482..0ca1260 100644
--- a/include/grpc++/completion_queue.h
+++ b/include/grpc++/completion_queue.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_COMPLETION_QUEUE_H__
-#define __GRPCPP_COMPLETION_QUEUE_H__
+#ifndef GRPCXX_COMPLETION_QUEUE_H
+#define GRPCXX_COMPLETION_QUEUE_H
 
 #include <grpc++/impl/client_unary_call.h>
 
@@ -121,4 +121,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_COMPLETION_QUEUE_H__
+#endif  // GRPCXX_COMPLETION_QUEUE_H
diff --git a/include/grpc++/config.h b/include/grpc++/config.h
index 323ea28..cfa8d3b 100644
--- a/include/grpc++/config.h
+++ b/include/grpc++/config.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CONFIG_H__
-#define __GRPCPP_CONFIG_H__
+#ifndef GRPCXX_CONFIG_H
+#define GRPCXX_CONFIG_H
 
 #include <string>
 
@@ -50,4 +50,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CONFIG_H__
+#endif  // GRPCXX_CONFIG_H
diff --git a/include/grpc++/create_channel.h b/include/grpc++/create_channel.h
index 80ca0c4..3f13188 100644
--- a/include/grpc++/create_channel.h
+++ b/include/grpc++/create_channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CREATE_CHANNEL_H__
-#define __GRPCPP_CREATE_CHANNEL_H__
+#ifndef GRPCXX_CREATE_CHANNEL_H
+#define GRPCXX_CREATE_CHANNEL_H
 
 #include <memory>
 
@@ -55,4 +55,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CREATE_CHANNEL_H__
+#endif  // GRPCXX_CREATE_CHANNEL_H
diff --git a/include/grpc++/credentials.h b/include/grpc++/credentials.h
index b75755d..12c1a2f 100644
--- a/include/grpc++/credentials.h
+++ b/include/grpc++/credentials.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CREDENTIALS_H_
-#define __GRPCPP_CREDENTIALS_H_
+#ifndef GRPCXX_CREDENTIALS_H
+#define GRPCXX_CREDENTIALS_H
 
 #include <chrono>
 #include <memory>
@@ -133,4 +133,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CREDENTIALS_H_
+#endif  // GRPCXX_CREDENTIALS_H
diff --git a/include/grpc++/impl/call.h b/include/grpc++/impl/call.h
index 92ad0c7..3e199e3 100644
--- a/include/grpc++/impl/call.h
+++ b/include/grpc++/impl/call.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CALL_H__
-#define __GRPCPP_CALL_H__
+#ifndef GRPCXX_IMPL_CALL_H
+#define GRPCXX_IMPL_CALL_H
 
 #include <grpc/grpc.h>
 #include <grpc++/config.h>
@@ -143,4 +143,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_CALL_INTERFACE_H__
+#endif  // GRPCXX_IMPL_CALL_H
diff --git a/include/grpc++/impl/client_unary_call.h b/include/grpc++/impl/client_unary_call.h
index f25ded7..d870326 100644
--- a/include/grpc++/impl/client_unary_call.h
+++ b/include/grpc++/impl/client_unary_call.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_CLIENT_UNARY_CALL_H__
-#define __GRPCPP_CLIENT_UNARY_CALL_H__
+#ifndef GRPCXX_IMPL_CLIENT_UNARY_CALL_H
+#define GRPCXX_IMPL_CLIENT_UNARY_CALL_H
 
 namespace google {
 namespace protobuf {
@@ -56,4 +56,4 @@
 
 }  // namespace grpc
 
-#endif
+#endif  // GRPCXX_IMPL_CLIENT_UNARY_CALL_H
diff --git a/include/grpc++/impl/internal_stub.h b/include/grpc++/impl/internal_stub.h
index 2529012..2cbf1d9 100644
--- a/include/grpc++/impl/internal_stub.h
+++ b/include/grpc++/impl/internal_stub.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_IMPL_INTERNAL_STUB_H__
-#define __GRPCPP_IMPL_INTERNAL_STUB_H__
+#ifndef GRPCXX_IMPL_INTERNAL_STUB_H
+#define GRPCXX_IMPL_INTERNAL_STUB_H
 
 #include <memory>
 
@@ -57,4 +57,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_IMPL_INTERNAL_STUB_H__
+#endif  // GRPCXX_IMPL_INTERNAL_STUB_H
diff --git a/include/grpc++/impl/rpc_method.h b/include/grpc++/impl/rpc_method.h
index 0236b11..ab407f5 100644
--- a/include/grpc++/impl/rpc_method.h
+++ b/include/grpc++/impl/rpc_method.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_IMPL_RPC_METHOD_H__
-#define __GRPCPP_IMPL_RPC_METHOD_H__
+#ifndef GRPCXX_IMPL_RPC_METHOD_H
+#define GRPCXX_IMPL_RPC_METHOD_H
 
 namespace google {
 namespace protobuf {
@@ -66,4 +66,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_IMPL_RPC_METHOD_H__
+#endif  // GRPCXX_IMPL_RPC_METHOD_H
diff --git a/include/grpc++/impl/rpc_service_method.h b/include/grpc++/impl/rpc_service_method.h
index a8794bc..ff94c7e 100644
--- a/include/grpc++/impl/rpc_service_method.h
+++ b/include/grpc++/impl/rpc_service_method.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_IMPL_RPC_SERVICE_METHOD_H__
-#define __GRPCPP_IMPL_RPC_SERVICE_METHOD_H__
+#ifndef GRPCXX_IMPL_RPC_SERVICE_METHOD_H
+#define GRPCXX_IMPL_RPC_SERVICE_METHOD_H
 
 #include <functional>
 #include <map>
@@ -203,4 +203,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_IMPL_RPC_SERVICE_METHOD_H__
+#endif  // GRPCXX_IMPL_RPC_SERVICE_METHOD_H
diff --git a/include/grpc++/impl/service_type.h b/include/grpc++/impl/service_type.h
index e54c3c2..7481d64 100644
--- a/include/grpc++/impl/service_type.h
+++ b/include/grpc++/impl/service_type.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_IMPL_SERVICE_TYPE_H__
-#define __GRPCPP_IMPL_SERVICE_TYPE_H__
+#ifndef GRPCXX_IMPL_SERVICE_TYPE_H
+#define GRPCXX_IMPL_SERVICE_TYPE_H
 
 namespace google {
 namespace protobuf {
@@ -128,4 +128,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_IMPL_SERVICE_TYPE_H__
+#endif  // GRPCXX_IMPL_SERVICE_TYPE_H
diff --git a/include/grpc++/server.h b/include/grpc++/server.h
index 46c4a62..3282b82 100644
--- a/include/grpc++/server.h
+++ b/include/grpc++/server.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_SERVER_H__
-#define __GRPCPP_SERVER_H__
+#ifndef GRPCXX_SERVER_H
+#define GRPCXX_SERVER_H
 
 #include <condition_variable>
 #include <list>
@@ -130,4 +130,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_SERVER_H__
+#endif  // GRPCXX_SERVER_H
diff --git a/include/grpc++/server_builder.h b/include/grpc++/server_builder.h
index b672eb3..5566002 100644
--- a/include/grpc++/server_builder.h
+++ b/include/grpc++/server_builder.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_SERVER_BUILDER_H__
-#define __GRPCPP_SERVER_BUILDER_H__
+#ifndef GRPCXX_SERVER_BUILDER_H
+#define GRPCXX_SERVER_BUILDER_H
 
 #include <memory>
 #include <vector>
@@ -88,4 +88,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_SERVER_BUILDER_H__
+#endif  // GRPCXX_SERVER_BUILDER_H
diff --git a/include/grpc++/server_context.h b/include/grpc++/server_context.h
index 6db767f..9387f4a 100644
--- a/include/grpc++/server_context.h
+++ b/include/grpc++/server_context.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_SERVER_CONTEXT_H_
-#define __GRPCPP_SERVER_CONTEXT_H_
+#ifndef GRPCXX_SERVER_CONTEXT_H
+#define GRPCXX_SERVER_CONTEXT_H
 
 #include <chrono>
 #include <map>
@@ -121,4 +121,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_SERVER_CONTEXT_H_
+#endif  // GRPCXX_SERVER_CONTEXT_H
diff --git a/include/grpc++/server_credentials.h b/include/grpc++/server_credentials.h
index 8af4159..45cd279 100644
--- a/include/grpc++/server_credentials.h
+++ b/include/grpc++/server_credentials.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_SERVER_CREDENTIALS_H_
-#define __GRPCPP_SERVER_CREDENTIALS_H_
+#ifndef GRPCXX_SERVER_CREDENTIALS_H
+#define GRPCXX_SERVER_CREDENTIALS_H
 
 #include <memory>
 #include <vector>
@@ -79,4 +79,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_SERVER_CREDENTIALS_H_
+#endif  // GRPCXX_SERVER_CREDENTIALS_H
diff --git a/include/grpc++/status.h b/include/grpc++/status.h
index 1dfb0c9..8073319 100644
--- a/include/grpc++/status.h
+++ b/include/grpc++/status.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_STATUS_H__
-#define __GRPCPP_STATUS_H__
+#ifndef GRPCXX_STATUS_H
+#define GRPCXX_STATUS_H
 
 #include <grpc++/status_code_enum.h>
 #include <grpc++/config.h>
@@ -62,4 +62,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_STATUS_H__
+#endif  // GRPCXX_STATUS_H
diff --git a/include/grpc++/status_code_enum.h b/include/grpc++/status_code_enum.h
index 0ec0a97..2728fb0 100644
--- a/include/grpc++/status_code_enum.h
+++ b/include/grpc++/status_code_enum.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_STATUS_CODE_ENUM_H__
-#define __GRPCPP_STATUS_CODE_ENUM_H__
+#ifndef GRPCXX_STATUS_CODE_ENUM_H
+#define GRPCXX_STATUS_CODE_ENUM_H
 
 namespace grpc {
 
@@ -195,4 +195,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_STATUS_CODE_ENUM_H_
+#endif  // GRPCXX_STATUS_CODE_ENUM_H
diff --git a/include/grpc++/stream.h b/include/grpc++/stream.h
index 8bcc75b..d95a379 100644
--- a/include/grpc++/stream.h
+++ b/include/grpc++/stream.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_STREAM_H__
-#define __GRPCPP_STREAM_H__
+#ifndef GRPCXX_STREAM_H
+#define GRPCXX_STREAM_H
 
 #include <grpc++/channel_interface.h>
 #include <grpc++/client_context.h>
@@ -710,4 +710,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_STREAM_H__
+#endif  // GRPCXX_STREAM_H
diff --git a/include/grpc++/thread_pool_interface.h b/include/grpc++/thread_pool_interface.h
index c839249..ead307f 100644
--- a/include/grpc++/thread_pool_interface.h
+++ b/include/grpc++/thread_pool_interface.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_THREAD_POOL_INTERFACE_H__
-#define __GRPCPP_THREAD_POOL_INTERFACE_H__
+#ifndef GRPCXX_THREAD_POOL_INTERFACE_H
+#define GRPCXX_THREAD_POOL_INTERFACE_H
 
 #include <functional>
 
@@ -49,4 +49,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_THREAD_POOL_INTERFACE_H__
+#endif  // GRPCXX_THREAD_POOL_INTERFACE_H
diff --git a/include/grpc/byte_buffer.h b/include/grpc/byte_buffer.h
index 89d8557e..0ff494c 100644
--- a/include/grpc/byte_buffer.h
+++ b/include/grpc/byte_buffer.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_BYTE_BUFFER_H__
-#define __GRPC_BYTE_BUFFER_H__
+#ifndef GRPC_BYTE_BUFFER_H
+#define GRPC_BYTE_BUFFER_H
 
 #include <grpc/grpc.h>
 #include <grpc/support/slice_buffer.h>
@@ -47,4 +47,4 @@
   } data;
 };
 
-#endif /* __GRPC_BYTE_BUFFER_H__ */
+#endif  /* GRPC_BYTE_BUFFER_H */
diff --git a/include/grpc/byte_buffer_reader.h b/include/grpc/byte_buffer_reader.h
index 4446e0c..cb757cf 100644
--- a/include/grpc/byte_buffer_reader.h
+++ b/include/grpc/byte_buffer_reader.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_BYTE_BUFFER_READER_H__
-#define __GRPC_BYTE_BUFFER_READER_H__
+#ifndef GRPC_BYTE_BUFFER_READER_H
+#define GRPC_BYTE_BUFFER_READER_H
 
 #include <grpc/grpc.h>
 #include <grpc/byte_buffer.h>
@@ -46,4 +46,4 @@
   } current;
 };
 
-#endif /* __GRPC_BYTE_BUFFER_READER_H__ */
+#endif  /* GRPC_BYTE_BUFFER_READER_H */
diff --git a/include/grpc/grpc.h b/include/grpc/grpc.h
index 4a720d1..bb16531 100644
--- a/include/grpc/grpc.h
+++ b/include/grpc/grpc.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_GRPC_H__
-#define __GRPC_GRPC_H__
+#ifndef GRPC_GRPC_H
+#define GRPC_GRPC_H
 
 #include <grpc/status.h>
 
@@ -632,4 +632,4 @@
 }
 #endif
 
-#endif /* __GRPC_GRPC_H__ */
+#endif  /* GRPC_GRPC_H */
diff --git a/include/grpc/grpc_http.h b/include/grpc/grpc_http.h
index 757f53f..c41e874 100644
--- a/include/grpc/grpc_http.h
+++ b/include/grpc/grpc_http.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_GRPC_HTTP_H__
-#define __GRPC_GRPC_HTTP_H__
+#ifndef GRPC_GRPC_HTTP_H
+#define GRPC_GRPC_HTTP_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -64,4 +64,4 @@
 }
 #endif
 
-#endif /* __GRPC_GRPC_HTTP_H__ */
+#endif  /* GRPC_GRPC_HTTP_H */
diff --git a/include/grpc/grpc_security.h b/include/grpc/grpc_security.h
index 4ba4ffc..577f03e 100644
--- a/include/grpc/grpc_security.h
+++ b/include/grpc/grpc_security.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef GRPC_SECURITY_H_
-#define GRPC_SECURITY_H_
+#ifndef GRPC_GRPC_SECURITY_H
+#define GRPC_GRPC_SECURITY_H
 
 #include "grpc.h"
 #include "status.h"
@@ -185,4 +185,4 @@
 }
 #endif
 
-#endif /* GRPC_SECURITY_H_ */
+#endif  /* GRPC_GRPC_SECURITY_H */
diff --git a/include/grpc/status.h b/include/grpc/status.h
index 76a71ed..a1a4d2f 100644
--- a/include/grpc/status.h
+++ b/include/grpc/status.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_STATUS_H__
-#define __GRPC_STATUS_H__
+#ifndef GRPC_STATUS_H
+#define GRPC_STATUS_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -199,4 +199,4 @@
 }
 #endif
 
-#endif /* __GRPC_STATUS_H__ */
+#endif  /* GRPC_STATUS_H */
diff --git a/include/grpc/support/alloc.h b/include/grpc/support/alloc.h
index 09ea975..509870f 100644
--- a/include/grpc/support/alloc.h
+++ b/include/grpc/support/alloc.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_ALLOC_H__
-#define __GRPC_SUPPORT_ALLOC_H__
+#ifndef GRPC_SUPPORT_ALLOC_H
+#define GRPC_SUPPORT_ALLOC_H
 
 #include <stddef.h>
 
@@ -55,4 +55,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_ALLOC_H__ */
+#endif  /* GRPC_SUPPORT_ALLOC_H */
diff --git a/include/grpc/support/atm.h b/include/grpc/support/atm.h
index f1e30d3..feca6b3 100644
--- a/include/grpc/support/atm.h
+++ b/include/grpc/support/atm.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_ATM_H__
-#define __GRPC_SUPPORT_ATM_H__
+#ifndef GRPC_SUPPORT_ATM_H
+#define GRPC_SUPPORT_ATM_H
 
 /* This interface provides atomic operations and barriers.
    It is internal to gpr support code and should not be used outside it.
@@ -89,4 +89,4 @@
 #error could not determine platform for atm
 #endif
 
-#endif /* __GRPC_SUPPORT_ATM_H__ */
+#endif  /* GRPC_SUPPORT_ATM_H */
diff --git a/include/grpc/support/atm_gcc_atomic.h b/include/grpc/support/atm_gcc_atomic.h
index 2ae24ae..11d78b4 100644
--- a/include/grpc/support/atm_gcc_atomic.h
+++ b/include/grpc/support/atm_gcc_atomic.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_ATM_GCC_ATOMIC_H__
-#define __GRPC_SUPPORT_ATM_GCC_ATOMIC_H__
+#ifndef GRPC_SUPPORT_ATM_GCC_ATOMIC_H
+#define GRPC_SUPPORT_ATM_GCC_ATOMIC_H
 
 /* atm_platform.h for gcc and gcc-like compilers with the
    __atomic_* interface.  */
@@ -66,4 +66,4 @@
                                      __ATOMIC_RELAXED);
 }
 
-#endif /* __GRPC_SUPPORT_ATM_GCC_ATOMIC_H__ */
+#endif  /* GRPC_SUPPORT_ATM_GCC_ATOMIC_H */
diff --git a/include/grpc/support/atm_gcc_sync.h b/include/grpc/support/atm_gcc_sync.h
index cec62e1..e863bfd 100644
--- a/include/grpc/support/atm_gcc_sync.h
+++ b/include/grpc/support/atm_gcc_sync.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_ATM_GCC_SYNC_H__
-#define __GRPC_SUPPORT_ATM_GCC_SYNC_H__
+#ifndef GRPC_SUPPORT_ATM_GCC_SYNC_H
+#define GRPC_SUPPORT_ATM_GCC_SYNC_H
 
 /* variant of atm_platform.h for gcc and gcc-like compiers with __sync_*
    interface */
@@ -70,4 +70,4 @@
 #define gpr_atm_acq_cas(p, o, n) (__sync_bool_compare_and_swap((p), (o), (n)))
 #define gpr_atm_rel_cas(p, o, n) gpr_atm_acq_cas((p), (o), (n))
 
-#endif /* __GRPC_SUPPORT_ATM_GCC_SYNC_H__ */
+#endif  /* GRPC_SUPPORT_ATM_GCC_SYNC_H */
diff --git a/include/grpc/support/atm_win32.h b/include/grpc/support/atm_win32.h
index 9bb1cfe..3b9113c 100644
--- a/include/grpc/support/atm_win32.h
+++ b/include/grpc/support/atm_win32.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_ATM_WIN32_H__
-#define __GRPC_SUPPORT_ATM_WIN32_H__
+#ifndef GRPC_SUPPORT_ATM_WIN32_H
+#define GRPC_SUPPORT_ATM_WIN32_H
 
 /* Win32 variant of atm_platform.h */
 #include <grpc/support/port_platform.h>
@@ -105,4 +105,4 @@
   return old;
 }
 
-#endif /* __GRPC_SUPPORT_ATM_WIN32_H__ */
+#endif  /* GRPC_SUPPORT_ATM_WIN32_H */
diff --git a/include/grpc/support/cancellable_platform.h b/include/grpc/support/cancellable_platform.h
index e77f9f1..e8e4b84 100644
--- a/include/grpc/support/cancellable_platform.h
+++ b/include/grpc/support/cancellable_platform.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_CANCELLABLE_PLATFORM_H__
-#define __GRPC_SUPPORT_CANCELLABLE_PLATFORM_H__
+#ifndef GRPC_SUPPORT_CANCELLABLE_PLATFORM_H
+#define GRPC_SUPPORT_CANCELLABLE_PLATFORM_H
 
 #include <grpc/support/atm.h>
 #include <grpc/support/sync.h>
@@ -53,4 +53,4 @@
   struct gpr_cancellable_list_ waiters;
 } gpr_cancellable;
 
-#endif /* __GRPC_SUPPORT_CANCELLABLE_PLATFORM_H__ */
+#endif  /* GRPC_SUPPORT_CANCELLABLE_PLATFORM_H */
diff --git a/include/grpc/support/cmdline.h b/include/grpc/support/cmdline.h
index 20de122..c2350a0 100644
--- a/include/grpc/support/cmdline.h
+++ b/include/grpc/support/cmdline.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_CMDLINE_H__
-#define __GRPC_SUPPORT_CMDLINE_H__
+#ifndef GRPC_SUPPORT_CMDLINE_H
+#define GRPC_SUPPORT_CMDLINE_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -92,4 +92,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_CMDLINE_H__ */
+#endif  /* GRPC_SUPPORT_CMDLINE_H */
diff --git a/include/grpc/support/cpu.h b/include/grpc/support/cpu.h
index 580f12d..005c3c7 100644
--- a/include/grpc/support/cpu.h
+++ b/include/grpc/support/cpu.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SUPPORT_CPU_H__
-#define __GRPC_INTERNAL_SUPPORT_CPU_H__
+#ifndef GRPC_SUPPORT_CPU_H
+#define GRPC_SUPPORT_CPU_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -54,4 +54,4 @@
 }  // extern "C"
 #endif
 
-#endif /* __GRPC_INTERNAL_SUPPORT_CPU_H__ */
+#endif  /* GRPC_SUPPORT_CPU_H */
diff --git a/include/grpc/support/histogram.h b/include/grpc/support/histogram.h
index fb9d3d1..31f7fed 100644
--- a/include/grpc/support/histogram.h
+++ b/include/grpc/support/histogram.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_HISTOGRAM_H__
-#define __GRPC_SUPPORT_HISTOGRAM_H__
+#ifndef GRPC_SUPPORT_HISTOGRAM_H
+#define GRPC_SUPPORT_HISTOGRAM_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -63,4 +63,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_HISTOGRAM_H__ */
+#endif  /* GRPC_SUPPORT_HISTOGRAM_H */
diff --git a/include/grpc/support/host_port.h b/include/grpc/support/host_port.h
index 2dac38a..3cc2f49 100644
--- a/include/grpc/support/host_port.h
+++ b/include/grpc/support/host_port.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_HOST_PORT_H__
-#define __GRPC_SUPPORT_HOST_PORT_H__
+#ifndef GRPC_SUPPORT_HOST_PORT_H
+#define GRPC_SUPPORT_HOST_PORT_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -59,4 +59,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_HOST_PORT_H__ */
+#endif  /* GRPC_SUPPORT_HOST_PORT_H */
diff --git a/include/grpc/support/log.h b/include/grpc/support/log.h
index c142949..aad4f23 100644
--- a/include/grpc/support/log.h
+++ b/include/grpc/support/log.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_LOG_H__
-#define __GRPC_SUPPORT_LOG_H__
+#ifndef GRPC_SUPPORT_LOG_H
+#define GRPC_SUPPORT_LOG_H
 
 #include <stdlib.h> /* for abort() */
 #include <stdarg.h>
@@ -105,4 +105,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_LOG_H__ */
+#endif  /* GRPC_SUPPORT_LOG_H */
diff --git a/include/grpc/support/log_win32.h b/include/grpc/support/log_win32.h
index 52d6a70..ad0edcd 100644
--- a/include/grpc/support/log_win32.h
+++ b/include/grpc/support/log_win32.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_LOG_WIN32_H__
-#define __GRPC_SUPPORT_LOG_WIN32_H__
+#ifndef GRPC_SUPPORT_LOG_WIN32_H
+#define GRPC_SUPPORT_LOG_WIN32_H
 
 #include <windows.h>
 
@@ -50,4 +50,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_LOG_H__ */
+#endif  /* GRPC_SUPPORT_LOG_WIN32_H */
diff --git a/include/grpc/support/port_platform.h b/include/grpc/support/port_platform.h
index 0a65175..f04c2e7 100644
--- a/include/grpc/support/port_platform.h
+++ b/include/grpc/support/port_platform.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_PORT_PLATFORM_H__
-#define __GRPC_SUPPORT_PORT_PLATFORM_H__
+#ifndef GRPC_SUPPORT_PORT_PLATFORM_H
+#define GRPC_SUPPORT_PORT_PLATFORM_H
 
 /* Override this file with one for your platform if you need to redefine
    things.  */
@@ -206,4 +206,4 @@
    power of two */
 #define GPR_MAX_ALIGNMENT 16
 
-#endif /* __GRPC_SUPPORT_PORT_PLATFORM_H__ */
+#endif  /* GRPC_SUPPORT_PORT_PLATFORM_H */
diff --git a/include/grpc/support/slice.h b/include/grpc/support/slice.h
index 8a21290..9026602 100644
--- a/include/grpc/support/slice.h
+++ b/include/grpc/support/slice.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_SLICE_H__
-#define __GRPC_SUPPORT_SLICE_H__
+#ifndef GRPC_SUPPORT_SLICE_H
+#define GRPC_SUPPORT_SLICE_H
 
 #include <grpc/support/sync.h>
 
@@ -175,4 +175,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_SLICE_H__ */
+#endif  /* GRPC_SUPPORT_SLICE_H */
diff --git a/include/grpc/support/slice_buffer.h b/include/grpc/support/slice_buffer.h
index 8b57f9f..56f71ef 100644
--- a/include/grpc/support/slice_buffer.h
+++ b/include/grpc/support/slice_buffer.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_SLICE_BUFFER_H__
-#define __GRPC_SUPPORT_SLICE_BUFFER_H__
+#ifndef GRPC_SUPPORT_SLICE_BUFFER_H
+#define GRPC_SUPPORT_SLICE_BUFFER_H
 
 #include <grpc/support/slice.h>
 
@@ -81,4 +81,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_SLICE_BUFFER_H__ */
+#endif  /* GRPC_SUPPORT_SLICE_BUFFER_H */
diff --git a/include/grpc/support/sync.h b/include/grpc/support/sync.h
index bc99317..35b2d12 100644
--- a/include/grpc/support/sync.h
+++ b/include/grpc/support/sync.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_SYNC_H__
-#define __GRPC_SUPPORT_SYNC_H__
+#ifndef GRPC_SUPPORT_SYNC_H
+#define GRPC_SUPPORT_SYNC_H
 /* Synchronization primitives for GPR.
 
    The type  gpr_mu              provides a non-reentrant mutex (lock).
@@ -345,4 +345,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_SYNC_H__ */
+#endif  /* GRPC_SUPPORT_SYNC_H */
diff --git a/include/grpc/support/sync_generic.h b/include/grpc/support/sync_generic.h
index 3bae222..bbd1b3e 100644
--- a/include/grpc/support/sync_generic.h
+++ b/include/grpc/support/sync_generic.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_SYNC_GENERIC_H__
-#define __GRPC_SUPPORT_SYNC_GENERIC_H__
+#ifndef GRPC_SUPPORT_SYNC_GENERIC_H
+#define GRPC_SUPPORT_SYNC_GENERIC_H
 /* Generic type defintions for gpr_sync. */
 
 #include <grpc/support/atm.h>
@@ -58,4 +58,4 @@
 #define GPR_STATS_INIT \
   { 0 }
 
-#endif /* __GRPC_SUPPORT_SYNC_GENERIC_H__ */
+#endif  /* GRPC_SUPPORT_SYNC_GENERIC_H */
diff --git a/include/grpc/support/sync_posix.h b/include/grpc/support/sync_posix.h
index 8ba2c5b..762d9eb 100644
--- a/include/grpc/support/sync_posix.h
+++ b/include/grpc/support/sync_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_SYNC_POSIX_H__
-#define __GRPC_SUPPORT_SYNC_POSIX_H__
+#ifndef GRPC_SUPPORT_SYNC_POSIX_H
+#define GRPC_SUPPORT_SYNC_POSIX_H
 
 #include <grpc/support/sync_generic.h>
 
@@ -44,4 +44,4 @@
 
 #define GPR_ONCE_INIT PTHREAD_ONCE_INIT
 
-#endif /* __GRPC_SUPPORT_SYNC_POSIX_H__ */
+#endif  /* GRPC_SUPPORT_SYNC_POSIX_H */
diff --git a/include/grpc/support/sync_win32.h b/include/grpc/support/sync_win32.h
index 13823b8..cb2a866 100644
--- a/include/grpc/support/sync_win32.h
+++ b/include/grpc/support/sync_win32.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_SYNC_WIN32_H__
-#define __GRPC_SUPPORT_SYNC_WIN32_H__
+#ifndef GRPC_SUPPORT_SYNC_WIN32_H
+#define GRPC_SUPPORT_SYNC_WIN32_H
 
 #include <grpc/support/sync_generic.h>
 
@@ -48,4 +48,4 @@
 typedef INIT_ONCE gpr_once;
 #define GPR_ONCE_INIT INIT_ONCE_STATIC_INIT
 
-#endif /* __GRPC_SUPPORT_SYNC_WIN32_H__ */
+#endif  /* GRPC_SUPPORT_SYNC_WIN32_H */
diff --git a/include/grpc/support/thd.h b/include/grpc/support/thd.h
index a81e6cd..64d5bed 100644
--- a/include/grpc/support/thd.h
+++ b/include/grpc/support/thd.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_THD_H__
-#define __GRPC_SUPPORT_THD_H__
+#ifndef GRPC_SUPPORT_THD_H
+#define GRPC_SUPPORT_THD_H
 /* Thread interface for GPR.
 
    Types
@@ -73,4 +73,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_THD_H__ */
+#endif  /* GRPC_SUPPORT_THD_H */
diff --git a/include/grpc/support/time.h b/include/grpc/support/time.h
index 150b7ac..1fd3181 100644
--- a/include/grpc/support/time.h
+++ b/include/grpc/support/time.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_TIME_H__
-#define __GRPC_SUPPORT_TIME_H__
+#ifndef GRPC_SUPPORT_TIME_H
+#define GRPC_SUPPORT_TIME_H
 /* Time support.
    We use gpr_timespec, which is analogous to struct timespec.  On some
    machines, absolute times may be in local time.  */
@@ -100,4 +100,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_TIME_H__ */
+#endif  /* GRPC_SUPPORT_TIME_H */
diff --git a/include/grpc/support/useful.h b/include/grpc/support/useful.h
index 8d756c3..979f3d0 100644
--- a/include/grpc/support/useful.h
+++ b/include/grpc/support/useful.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_USEFUL_H__
-#define __GRPC_SUPPORT_USEFUL_H__
+#ifndef GRPC_SUPPORT_USEFUL_H
+#define GRPC_SUPPORT_USEFUL_H
 
 /* useful macros that don't belong anywhere else */
 
@@ -45,4 +45,4 @@
 
 #define GPR_ARRAY_SIZE(array) (sizeof(array) / sizeof(*(array)))
 
-#endif /* __GRPC_SUPPORT_USEFUL_H__ */
+#endif  /* GRPC_SUPPORT_USEFUL_H */
diff --git a/src/compiler/cpp_generator.h b/src/compiler/cpp_generator.h
index f5b1ad2..1bfe5a8 100644
--- a/src/compiler/cpp_generator.h
+++ b/src/compiler/cpp_generator.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_CPP_GENERATOR_H_
-#define NET_GRPC_COMPILER_CPP_GENERATOR_H_
+#ifndef GRPC_INTERNAL_COMPILER_CPP_GENERATOR_H
+#define GRPC_INTERNAL_COMPILER_CPP_GENERATOR_H
 
 #include <string>
 
@@ -58,4 +58,4 @@
 
 }  // namespace grpc_cpp_generator
 
-#endif  // NET_GRPC_COMPILER_CPP_GENERATOR_H_
+#endif  // GRPC_INTERNAL_COMPILER_CPP_GENERATOR_H
diff --git a/src/compiler/cpp_generator_helpers.h b/src/compiler/cpp_generator_helpers.h
index 632ff3c..16abbde 100644
--- a/src/compiler/cpp_generator_helpers.h
+++ b/src/compiler/cpp_generator_helpers.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_CPP_GENERATOR_HELPERS_H__
-#define NET_GRPC_COMPILER_CPP_GENERATOR_HELPERS_H__
+#ifndef GRPC_INTERNAL_COMPILER_CPP_GENERATOR_HELPERS_H
+#define GRPC_INTERNAL_COMPILER_CPP_GENERATOR_HELPERS_H
 
 #include <map>
 #include <string>
@@ -69,4 +69,4 @@
 
 }  // namespace grpc_cpp_generator
 
-#endif  // NET_GRPC_COMPILER_CPP_GENERATOR_HELPERS_H__
+#endif  // GRPC_INTERNAL_COMPILER_CPP_GENERATOR_HELPERS_H
diff --git a/src/compiler/generator_helpers.h b/src/compiler/generator_helpers.h
index 0c14bb8..2035820 100644
--- a/src/compiler/generator_helpers.h
+++ b/src/compiler/generator_helpers.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_GENERATOR_HELPERS_H__
-#define NET_GRPC_COMPILER_GENERATOR_HELPERS_H__
+#ifndef GRPC_INTERNAL_COMPILER_GENERATOR_HELPERS_H
+#define GRPC_INTERNAL_COMPILER_GENERATOR_HELPERS_H
 
 #include <map>
 #include <string>
@@ -76,4 +76,4 @@
 
 }  // namespace grpc_generator
 
-#endif  // NET_GRPC_COMPILER_GENERATOR_HELPERS_H__
+#endif  // GRPC_INTERNAL_COMPILER_GENERATOR_HELPERS_H
diff --git a/src/compiler/python_generator.h b/src/compiler/python_generator.h
index 773dfa3..df29ca1 100644
--- a/src/compiler/python_generator.h
+++ b/src/compiler/python_generator.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_COMPILER_PYTHON_GENERATOR_H__
-#define __GRPC_COMPILER_PYTHON_GENERATOR_H__
+#ifndef GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
+#define GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
 
 #include <string>
 #include <utility>
@@ -49,4 +49,4 @@
 
 }  // namespace grpc_python_generator
 
-#endif  // __GRPC_COMPILER_PYTHON_GENERATOR_H__
+#endif  // GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
diff --git a/src/compiler/ruby_generator.h b/src/compiler/ruby_generator.h
index d0c568f..4dd38e0 100644
--- a/src/compiler/ruby_generator.h
+++ b/src/compiler/ruby_generator.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_RUBY_GENERATOR_H_
-#define NET_GRPC_COMPILER_RUBY_GENERATOR_H_
+#ifndef GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_H
+#define GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_H
 
 #include <string>
 
@@ -48,4 +48,4 @@
 
 }  // namespace grpc_ruby_generator
 
-#endif  // NET_GRPC_COMPILER_RUBY_GENERATOR_H_
+#endif  // GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_H
diff --git a/src/compiler/ruby_generator_helpers-inl.h b/src/compiler/ruby_generator_helpers-inl.h
index 61d887b..f3a087b 100644
--- a/src/compiler/ruby_generator_helpers-inl.h
+++ b/src/compiler/ruby_generator_helpers-inl.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_RUBY_GENERATOR_HELPERS_INL_H_
-#define NET_GRPC_COMPILER_RUBY_GENERATOR_HELPERS_INL_H_
+#ifndef GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_HELPERS_INL_H
+#define GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_HELPERS_INL_H
 
 #include <string>
 
@@ -64,4 +64,4 @@
 
 }  // namespace grpc_ruby_generator
 
-#endif  // NET_GRPC_COMPILER_RUBY_GENERATOR_HELPERS_INL_H_
+#endif  // GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_HELPERS_INL_H
diff --git a/src/compiler/ruby_generator_map-inl.h b/src/compiler/ruby_generator_map-inl.h
index a86342e..f902b6d 100644
--- a/src/compiler/ruby_generator_map-inl.h
+++ b/src/compiler/ruby_generator_map-inl.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_RUBY_GENERATOR_MAP_INL_H_
-#define NET_GRPC_COMPILER_RUBY_GENERATOR_MAP_INL_H_
+#ifndef GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_MAP_INL_H
+#define GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_MAP_INL_H
 
 #include <iostream>
 #include <initializer_list>
@@ -69,4 +69,4 @@
 
 }  // namespace grpc_ruby_generator
 
-#endif  // NET_GRPC_COMPILER_RUBY_GENERATOR_MAP_INL_H_
+#endif  // GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_MAP_INL_H
diff --git a/src/compiler/ruby_generator_string-inl.h b/src/compiler/ruby_generator_string-inl.h
index 7c2e4e5..bdd314c 100644
--- a/src/compiler/ruby_generator_string-inl.h
+++ b/src/compiler/ruby_generator_string-inl.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef NET_GRPC_COMPILER_RUBY_GENERATOR_STRING_INL_H_
-#define NET_GRPC_COMPILER_RUBY_GENERATOR_STRING_INL_H_
+#ifndef GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_STRING_INL_H
+#define GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_STRING_INL_H
 
 #include <algorithm>
 #include <string>
@@ -130,4 +130,4 @@
 
 }  // namespace grpc_ruby_generator
 
-#endif  // NET_GRPC_COMPILER_RUBY_GENERATOR_STRING_INL_H_
+#endif  // GRPC_INTERNAL_COMPILER_RUBY_GENERATOR_STRING_INL_H
diff --git a/src/core/channel/census_filter.h b/src/core/channel/census_filter.h
index 6acf969..4f9759f 100644
--- a/src/core/channel/census_filter.h
+++ b/src/core/channel/census_filter.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CENSUS_FILTER_H__
-#define __GRPC_INTERNAL_CHANNEL_CENSUS_FILTER_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CENSUS_FILTER_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CENSUS_FILTER_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -41,4 +41,4 @@
 extern const grpc_channel_filter grpc_client_census_filter;
 extern const grpc_channel_filter grpc_server_census_filter;
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CENSUS_FILTER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CENSUS_FILTER_H */
diff --git a/src/core/channel/channel_args.h b/src/core/channel/channel_args.h
index 640bbd8..eb5bf63 100644
--- a/src/core/channel/channel_args.h
+++ b/src/core/channel/channel_args.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CHANNEL_ARGS_H__
-#define __GRPC_INTERNAL_CHANNEL_CHANNEL_ARGS_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_ARGS_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_ARGS_H
 
 #include <grpc/grpc.h>
 
@@ -51,4 +51,4 @@
    is specified in channel args, otherwise returns 0. */
 int grpc_channel_args_is_census_enabled(const grpc_channel_args *a);
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CHANNEL_ARGS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_ARGS_H */
diff --git a/src/core/channel/channel_stack.h b/src/core/channel/channel_stack.h
index 1ca95e7..c136f5c 100644
--- a/src/core/channel/channel_stack.h
+++ b/src/core/channel/channel_stack.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CHANNEL_STACK_H__
-#define __GRPC_INTERNAL_CHANNEL_CHANNEL_STACK_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_STACK_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_STACK_H
 
 /* A channel filter defines how operations on a channel are implemented.
    Channel filters are chained together to create full channels, and if those
@@ -301,4 +301,4 @@
 #define GRPC_CALL_LOG_OP(sev, elem, op) \
   if (grpc_trace_bits & GRPC_TRACE_CHANNEL) grpc_call_log_op(sev, elem, op)
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CHANNEL_STACK_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_STACK_H */
diff --git a/src/core/channel/child_channel.h b/src/core/channel/child_channel.h
index 84a1106..3869540 100644
--- a/src/core/channel/child_channel.h
+++ b/src/core/channel/child_channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CHILD_CHANNEL_H_
-#define __GRPC_INTERNAL_CHANNEL_CHILD_CHANNEL_H_
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CHILD_CHANNEL_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CHILD_CHANNEL_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -61,4 +61,4 @@
 grpc_call_element *grpc_child_call_get_top_element(grpc_child_call *call);
 void grpc_child_call_destroy(grpc_child_call *call);
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CHILD_CHANNEL_H_ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CHILD_CHANNEL_H */
diff --git a/src/core/channel/client_channel.h b/src/core/channel/client_channel.h
index 7da4fc9..7a67a9f 100644
--- a/src/core/channel/client_channel.h
+++ b/src/core/channel/client_channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CLIENT_CHANNEL_H__
-#define __GRPC_INTERNAL_CHANNEL_CLIENT_CHANNEL_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CLIENT_CHANNEL_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CLIENT_CHANNEL_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -59,4 +59,4 @@
     grpc_channel_filter const **channel_filters, size_t num_channel_filters,
     grpc_mdctx *mdctx);
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CLIENT_CHANNEL_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CLIENT_CHANNEL_H */
diff --git a/src/core/channel/client_setup.h b/src/core/channel/client_setup.h
index f2b6426..70137e1 100644
--- a/src/core/channel/client_setup.h
+++ b/src/core/channel/client_setup.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CLIENT_SETUP_H__
-#define __GRPC_INTERNAL_CHANNEL_CLIENT_SETUP_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CLIENT_SETUP_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CLIENT_SETUP_H
 
 #include "src/core/channel/client_channel.h"
 #include "src/core/transport/metadata.h"
@@ -70,4 +70,4 @@
 
 grpc_mdctx *grpc_client_setup_get_mdctx(grpc_client_setup_request *r);
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CLIENT_SETUP_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CLIENT_SETUP_H */
diff --git a/src/core/channel/connected_channel.h b/src/core/channel/connected_channel.h
index e19de62..8b35f69 100644
--- a/src/core/channel/connected_channel.h
+++ b/src/core/channel/connected_channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_CONNECTED_CHANNEL_H__
-#define __GRPC_INTERNAL_CHANNEL_CONNECTED_CHANNEL_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_CONNECTED_CHANNEL_H
+#define GRPC_INTERNAL_CORE_CHANNEL_CONNECTED_CHANNEL_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -46,4 +46,4 @@
 grpc_transport_setup_result grpc_connected_channel_bind_transport(
     grpc_channel_stack *channel_stack, grpc_transport *transport);
 
-#endif /* __GRPC_INTERNAL_CHANNEL_CONNECTED_CHANNEL_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CONNECTED_CHANNEL_H */
diff --git a/src/core/channel/http_client_filter.h b/src/core/channel/http_client_filter.h
index 5882f8f..04eb839 100644
--- a/src/core/channel/http_client_filter.h
+++ b/src/core/channel/http_client_filter.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_HTTP_CLIENT_FILTER_H__
-#define __GRPC_INTERNAL_CHANNEL_HTTP_CLIENT_FILTER_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_HTTP_CLIENT_FILTER_H
+#define GRPC_INTERNAL_CORE_CHANNEL_HTTP_CLIENT_FILTER_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -41,4 +41,4 @@
 
 #define GRPC_ARG_HTTP2_SCHEME "grpc.http2_scheme"
 
-#endif /* __GRPC_INTERNAL_CHANNEL_HTTP_CLIENT_FILTER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_CLIENT_FILTER_H */
diff --git a/src/core/channel/http_filter.h b/src/core/channel/http_filter.h
index b85cd39..1b116ad 100644
--- a/src/core/channel/http_filter.h
+++ b/src/core/channel/http_filter.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_HTTP_FILTER_H__
-#define __GRPC_INTERNAL_CHANNEL_HTTP_FILTER_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_HTTP_FILTER_H
+#define GRPC_INTERNAL_CORE_CHANNEL_HTTP_FILTER_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -40,4 +40,4 @@
    transports. */
 extern const grpc_channel_filter grpc_http_filter;
 
-#endif /* __GRPC_INTERNAL_CHANNEL_HTTP_FILTER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_FILTER_H */
diff --git a/src/core/channel/http_server_filter.h b/src/core/channel/http_server_filter.h
index 0643c7b..42f76ed 100644
--- a/src/core/channel/http_server_filter.h
+++ b/src/core/channel/http_server_filter.h
@@ -31,12 +31,12 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_HTTP_SERVER_FILTER_H__
-#define __GRPC_INTERNAL_CHANNEL_HTTP_SERVER_FILTER_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_HTTP_SERVER_FILTER_H
+#define GRPC_INTERNAL_CORE_CHANNEL_HTTP_SERVER_FILTER_H
 
 #include "src/core/channel/channel_stack.h"
 
 /* Processes metadata on the client side for HTTP2 transports */
 extern const grpc_channel_filter grpc_http_server_filter;
 
-#endif /* __GRPC_INTERNAL_CHANNEL_HTTP_SERVER_FILTER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_SERVER_FILTER_H */
diff --git a/src/core/channel/metadata_buffer.h b/src/core/channel/metadata_buffer.h
index 701d69d..b7cc517 100644
--- a/src/core/channel/metadata_buffer.h
+++ b/src/core/channel/metadata_buffer.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_METADATA_BUFFER_H__
-#define __GRPC_INTERNAL_CHANNEL_METADATA_BUFFER_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_METADATA_BUFFER_H
+#define GRPC_INTERNAL_CORE_CHANNEL_METADATA_BUFFER_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -67,4 +67,4 @@
     grpc_metadata_buffer *buffer);
 void grpc_metadata_buffer_cleanup_elements(void *elements, grpc_op_error error);
 
-#endif /* __GRPC_INTERNAL_CHANNEL_METADATA_BUFFER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_METADATA_BUFFER_H */
diff --git a/src/core/channel/noop_filter.h b/src/core/channel/noop_filter.h
index 93c2bff..96463e5 100644
--- a/src/core/channel/noop_filter.h
+++ b/src/core/channel/noop_filter.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_CHANNEL_NOOP_FILTER_H__
-#define __GRPC_INTERNAL_CHANNEL_NOOP_FILTER_H__
+#ifndef GRPC_INTERNAL_CORE_CHANNEL_NOOP_FILTER_H
+#define GRPC_INTERNAL_CORE_CHANNEL_NOOP_FILTER_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -41,4 +41,4 @@
    customize for their own filters */
 extern const grpc_channel_filter grpc_no_op_filter;
 
-#endif /* __GRPC_INTERNAL_CHANNEL_NOOP_FILTER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_CHANNEL_NOOP_FILTER_H */
diff --git a/src/core/compression/algorithm.h b/src/core/compression/algorithm.h
index e398ae3..9dd9f57 100644
--- a/src/core/compression/algorithm.h
+++ b/src/core/compression/algorithm.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_COMPRESSION_ALGORITHM_H__
-#define __GRPC_INTERNAL_COMPRESSION_ALGORITHM_H__
+#ifndef GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_H
+#define GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_H
 
 /* The various compression algorithms supported by GRPC */
 typedef enum {
@@ -46,4 +46,4 @@
 const char *grpc_compression_algorithm_name(
     grpc_compression_algorithm algorithm);
 
-#endif /* __GRPC_INTERNAL_COMPRESSION_ALGORITHM_H__ */
+#endif  /* GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_H */
diff --git a/src/core/compression/message_compress.h b/src/core/compression/message_compress.h
index 666da2e..e8aef1a 100644
--- a/src/core/compression/message_compress.h
+++ b/src/core/compression/message_compress.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_COMPRESSION_MESSAGE_COMPRESS_H__
-#define __GRPC_INTERNAL_COMPRESSION_MESSAGE_COMPRESS_H__
+#ifndef GRPC_INTERNAL_CORE_COMPRESSION_MESSAGE_COMPRESS_H
+#define GRPC_INTERNAL_CORE_COMPRESSION_MESSAGE_COMPRESS_H
 
 #include "src/core/compression/algorithm.h"
 #include <grpc/support/slice_buffer.h>
@@ -49,4 +49,4 @@
 int grpc_msg_decompress(grpc_compression_algorithm algorithm,
                         gpr_slice_buffer *input, gpr_slice_buffer *output);
 
-#endif /* __GRPC_INTERNAL_COMPRESSION_MESSAGE_COMPRESS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_COMPRESSION_MESSAGE_COMPRESS_H */
diff --git a/src/core/debug/trace.h b/src/core/debug/trace.h
index bf9b8a3..2059599 100644
--- a/src/core/debug/trace.h
+++ b/src/core/debug/trace.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef GRPC_CORE_DEBUG_TRACE_H
-#define GRPC_CORE_DEBUG_TRACE_H
+#ifndef GRPC_INTERNAL_CORE_DEBUG_TRACE_H
+#define GRPC_INTERNAL_CORE_DEBUG_TRACE_H
 
 #include <grpc/support/port_platform.h>
 
@@ -57,5 +57,4 @@
 
 void grpc_init_trace_bits();
 
-#endif
-
+#endif  /* GRPC_INTERNAL_CORE_DEBUG_TRACE_H */
diff --git a/src/core/httpcli/format_request.h b/src/core/httpcli/format_request.h
index e06b632..8bfb20b 100644
--- a/src/core/httpcli/format_request.h
+++ b/src/core/httpcli/format_request.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_HTTPCLI_FORMAT_REQUEST_H__
-#define __GRPC_INTERNAL_HTTPCLI_FORMAT_REQUEST_H__
+#ifndef GRPC_INTERNAL_CORE_HTTPCLI_FORMAT_REQUEST_H
+#define GRPC_INTERNAL_CORE_HTTPCLI_FORMAT_REQUEST_H
 
 #include "src/core/httpcli/httpcli.h"
 #include <grpc/support/slice.h>
@@ -42,4 +42,4 @@
                                            const char *body_bytes,
                                            size_t body_size);
 
-#endif /* __GRPC_INTERNAL_HTTPCLI_FORMAT_REQUEST_H__ */
+#endif  /* GRPC_INTERNAL_CORE_HTTPCLI_FORMAT_REQUEST_H */
diff --git a/src/core/httpcli/httpcli.h b/src/core/httpcli/httpcli.h
index f620987..255c5ed 100644
--- a/src/core/httpcli/httpcli.h
+++ b/src/core/httpcli/httpcli.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_HTTPCLI_HTTPCLI_H__
-#define __GRPC_INTERNAL_HTTPCLI_HTTPCLI_H__
+#ifndef GRPC_INTERNAL_CORE_HTTPCLI_HTTPCLI_H
+#define GRPC_INTERNAL_CORE_HTTPCLI_HTTPCLI_H
 
 #include <stddef.h>
 
@@ -115,4 +115,4 @@
 void grpc_httpcli_set_override(grpc_httpcli_get_override get,
                                grpc_httpcli_post_override post);
 
-#endif /* __GRPC_INTERNAL_HTTPCLI_HTTPCLI_H__ */
+#endif  /* GRPC_INTERNAL_CORE_HTTPCLI_HTTPCLI_H */
diff --git a/src/core/httpcli/httpcli_security_context.h b/src/core/httpcli/httpcli_security_context.h
index 5a1311e..a776828 100644
--- a/src/core/httpcli/httpcli_security_context.h
+++ b/src/core/httpcli/httpcli_security_context.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_HTTPCLI_HTTPCLI_SECURITY_CONTEXT_H__
-#define __GRPC_INTERNAL_HTTPCLI_HTTPCLI_SECURITY_CONTEXT_H__
+#ifndef GRPC_INTERNAL_CORE_HTTPCLI_HTTPCLI_SECURITY_CONTEXT_H
+#define GRPC_INTERNAL_CORE_HTTPCLI_HTTPCLI_SECURITY_CONTEXT_H
 
 #include "src/core/security/security_context.h"
 
@@ -40,4 +40,4 @@
     const unsigned char *pem_root_certs, size_t pem_root_certs_size,
     const char *secure_peer_name, grpc_channel_security_context **ctx);
 
-#endif /* __GRPC_INTERNAL_HTTPCLI_HTTPCLI_SECURITY_CONTEXT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_HTTPCLI_HTTPCLI_SECURITY_CONTEXT_H */
diff --git a/src/core/httpcli/parser.h b/src/core/httpcli/parser.h
index db1fa0a..71280e7 100644
--- a/src/core/httpcli/parser.h
+++ b/src/core/httpcli/parser.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_HTTPCLI_PARSER_H__
-#define __GRPC_INTERNAL_HTTPCLI_PARSER_H__
+#ifndef GRPC_INTERNAL_CORE_HTTPCLI_PARSER_H
+#define GRPC_INTERNAL_CORE_HTTPCLI_PARSER_H
 
 #include "src/core/httpcli/httpcli.h"
 #include <grpc/support/port_platform.h>
@@ -61,4 +61,4 @@
 int grpc_httpcli_parser_parse(grpc_httpcli_parser *parser, gpr_slice slice);
 int grpc_httpcli_parser_eof(grpc_httpcli_parser *parser);
 
-#endif /* __GRPC_INTERNAL_HTTPCLI_PARSER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_HTTPCLI_PARSER_H */
diff --git a/src/core/iomgr/alarm.h b/src/core/iomgr/alarm.h
index 6dcc63a..e5262e2 100644
--- a/src/core/iomgr/alarm.h
+++ b/src/core/iomgr/alarm.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_ALARM_H__
-#define __GRPC_INTERNAL_IOMGR_ALARM_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_ALARM_H
+#define GRPC_INTERNAL_CORE_IOMGR_ALARM_H
 
 #include "src/core/iomgr/iomgr.h"
 #include <grpc/support/port_platform.h>
@@ -86,4 +86,4 @@
    Requires:  cancel() must happen after add() on a given alarm */
 void grpc_alarm_cancel(grpc_alarm *alarm);
 
-#endif /* __GRPC_INTERNAL_IOMGR_ALARM_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_ALARM_H */
diff --git a/src/core/iomgr/alarm_heap.h b/src/core/iomgr/alarm_heap.h
index bb6e5e3..c5adfc6 100644
--- a/src/core/iomgr/alarm_heap.h
+++ b/src/core/iomgr/alarm_heap.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_ALARM_HEAP_H_
-#define __GRPC_INTERNAL_IOMGR_ALARM_HEAP_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_ALARM_HEAP_H
+#define GRPC_INTERNAL_CORE_IOMGR_ALARM_HEAP_H
 
 #include "src/core/iomgr/alarm.h"
 
@@ -54,4 +54,4 @@
 
 int grpc_alarm_heap_is_empty(grpc_alarm_heap *heap);
 
-#endif /* __GRPC_INTERNAL_IOMGR_ALARM_HEAP_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_ALARM_HEAP_H */
diff --git a/src/core/iomgr/alarm_internal.h b/src/core/iomgr/alarm_internal.h
index cbd8fa9..0268a01 100644
--- a/src/core/iomgr/alarm_internal.h
+++ b/src/core/iomgr/alarm_internal.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_ALARM_INTERNAL_H_
-#define __GRPC_INTERNAL_IOMGR_ALARM_INTERNAL_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_ALARM_INTERNAL_H
+#define GRPC_INTERNAL_CORE_IOMGR_ALARM_INTERNAL_H
 
 #include <grpc/support/sync.h>
 #include <grpc/support/time.h>
@@ -59,4 +59,4 @@
 
 void grpc_kick_poller(void);
 
-#endif /* __GRPC_INTERNAL_IOMGR_ALARM_INTERNAL_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_ALARM_INTERNAL_H */
diff --git a/src/core/iomgr/endpoint.h b/src/core/iomgr/endpoint.h
index e89cf66..881e851 100644
--- a/src/core/iomgr/endpoint.h
+++ b/src/core/iomgr/endpoint.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_ENDPOINT_H__
-#define __GRPC_INTERNAL_IOMGR_ENDPOINT_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H
+#define GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H
 
 #include "src/core/iomgr/pollset.h"
 #include <grpc/support/slice.h>
@@ -103,4 +103,4 @@
   const grpc_endpoint_vtable *vtable;
 };
 
-#endif /* __GRPC_INTERNAL_IOMGR_ENDPOINT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H */
diff --git a/src/core/iomgr/endpoint_pair.h b/src/core/iomgr/endpoint_pair.h
index 2e46aab..dffbd36 100644
--- a/src/core/iomgr/endpoint_pair.h
+++ b/src/core/iomgr/endpoint_pair.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_ENDPOINT_PAIR_H_
-#define __GRPC_INTERNAL_IOMGR_ENDPOINT_PAIR_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_PAIR_H
+#define GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_PAIR_H
 
 #include "src/core/iomgr/endpoint.h"
 
@@ -43,4 +43,4 @@
 
 grpc_endpoint_pair grpc_iomgr_create_endpoint_pair(size_t read_slice_size);
 
-#endif /* __GRPC_INTERNAL_IOMGR_ENDPOINT_PAIR_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_PAIR_H */
diff --git a/src/core/iomgr/fd_posix.h b/src/core/iomgr/fd_posix.h
index 2a308c8..be21f2b 100644
--- a/src/core/iomgr/fd_posix.h
+++ b/src/core/iomgr/fd_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_FD_POSIX_H_
-#define __GRPC_INTERNAL_IOMGR_FD_POSIX_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_FD_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_FD_POSIX_H
 
 #include "src/core/iomgr/iomgr.h"
 #include "src/core/iomgr/pollset.h"
@@ -143,4 +143,4 @@
 void grpc_fd_global_init(void);
 void grpc_fd_global_shutdown(void);
 
-#endif /* __GRPC_INTERNAL_IOMGR_FD_POSIX_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_FD_POSIX_H */
diff --git a/src/core/iomgr/iocp_windows.h b/src/core/iomgr/iocp_windows.h
index d023170..3313319 100644
--- a/src/core/iomgr/iocp_windows.h
+++ b/src/core/iomgr/iocp_windows.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_IOCP_WINDOWS_H_
-#define __GRPC_INTERNAL_IOMGR_IOCP_WINDOWS_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_IOCP_WINDOWS_H
+#define GRPC_INTERNAL_CORE_IOMGR_IOCP_WINDOWS_H
 
 #include <windows.h>
 #include <grpc/support/sync.h>
@@ -49,4 +49,4 @@
 void grpc_socket_notify_on_read(grpc_winsocket *, void(*cb)(void *, int success),
                                 void *opaque);
 
-#endif /* __GRPC_INTERNAL_IOMGR_IOCP_WINDOWS_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOCP_WINDOWS_H */
diff --git a/src/core/iomgr/iomgr.h b/src/core/iomgr/iomgr.h
index 18a7d15..1f5d23f 100644
--- a/src/core/iomgr/iomgr.h
+++ b/src/core/iomgr/iomgr.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_IOMGR_H__
-#define __GRPC_INTERNAL_IOMGR_IOMGR_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_IOMGR_H
+#define GRPC_INTERNAL_CORE_IOMGR_IOMGR_H
 
 /* gRPC Callback definition */
 typedef void (*grpc_iomgr_cb_func)(void *arg, int success);
@@ -44,4 +44,4 @@
    and causes the invocation of a callback at some point in the future */
 void grpc_iomgr_add_callback(grpc_iomgr_cb_func cb, void *cb_arg);
 
-#endif /* __GRPC_INTERNAL_IOMGR_IOMGR_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_H */
diff --git a/src/core/iomgr/iomgr_internal.h b/src/core/iomgr/iomgr_internal.h
index 7f29f44..0792325 100644
--- a/src/core/iomgr/iomgr_internal.h
+++ b/src/core/iomgr/iomgr_internal.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_IOMGR_INTERNAL_H_
-#define __GRPC_INTERNAL_IOMGR_IOMGR_INTERNAL_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_IOMGR_INTERNAL_H
+#define GRPC_INTERNAL_CORE_IOMGR_IOMGR_INTERNAL_H
 
 #include "src/core/iomgr/iomgr.h"
 #include "src/core/iomgr/iomgr_internal.h"
@@ -48,4 +48,4 @@
 void grpc_iomgr_platform_init(void);
 void grpc_iomgr_platform_shutdown(void);
 
-#endif /* __GRPC_INTERNAL_IOMGR_IOMGR_INTERNAL_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_INTERNAL_H */
diff --git a/src/core/iomgr/iomgr_posix.h b/src/core/iomgr/iomgr_posix.h
index f9e9b3d..a404f64 100644
--- a/src/core/iomgr/iomgr_posix.h
+++ b/src/core/iomgr/iomgr_posix.h
@@ -31,12 +31,12 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_IOMGR_POSIX_H_
-#define __GRPC_INTERNAL_IOMGR_IOMGR_POSIX_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_IOMGR_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_IOMGR_POSIX_H
 
 #include "src/core/iomgr/iomgr_internal.h"
 
 void grpc_pollset_global_init(void);
 void grpc_pollset_global_shutdown(void);
 
-#endif /* __GRPC_INTERNAL_IOMGR_IOMGR_POSIX_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_POSIX_H */
diff --git a/src/core/iomgr/pollset.h b/src/core/iomgr/pollset.h
index c26947f..067af87 100644
--- a/src/core/iomgr/pollset.h
+++ b/src/core/iomgr/pollset.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_H_
-#define __GRPC_INTERNAL_IOMGR_POLLSET_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_H
+#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_H
 
 #include <grpc/support/port_platform.h>
 #include <grpc/support/time.h>
@@ -71,4 +71,4 @@
    Requires GRPC_POLLSET_MU(pollset) locked. */
 void grpc_pollset_kick(grpc_pollset *pollset);
 
-#endif /* __GRPC_INTERNAL_IOMGR_POLLSET_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_H */
diff --git a/src/core/iomgr/pollset_kick.h b/src/core/iomgr/pollset_kick.h
index b224177..cc9357d 100644
--- a/src/core/iomgr/pollset_kick.h
+++ b/src/core/iomgr/pollset_kick.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_
-#define __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_H
+#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_H
 
 #include <grpc/support/port_platform.h>
 
@@ -71,4 +71,4 @@
 
 void grpc_pollset_kick_kick(grpc_pollset_kick_state *kick_state);
 
-#endif /* __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_H */
diff --git a/src/core/iomgr/pollset_kick_posix.h b/src/core/iomgr/pollset_kick_posix.h
index 162ae5b..4276991 100644
--- a/src/core/iomgr/pollset_kick_posix.h
+++ b/src/core/iomgr/pollset_kick_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_KICK_POSIX_H_
-#define __GRPC_INTERNAL_IOMGR_POLLSET_KICK_POSIX_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_POSIX_H
 
 #include "src/core/iomgr/wakeup_fd_posix.h"
 #include <grpc/support/sync.h>
@@ -48,4 +48,4 @@
   struct grpc_kick_fd_info *fd_info;
 } grpc_pollset_kick_state;
 
-#endif  /* __GRPC_INTERNALIOMGR_POLLSET_KICK_POSIX_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_POSIX_H */
diff --git a/src/core/iomgr/pollset_kick_windows.h b/src/core/iomgr/pollset_kick_windows.h
index 1053230..3836aa0 100644
--- a/src/core/iomgr/pollset_kick_windows.h
+++ b/src/core/iomgr/pollset_kick_windows.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_KICK_WINDOWS_H_
-#define __GRPC_INTERNAL_IOMGR_POLLSET_KICK_WINDOWS_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_WINDOWS_H
+#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_WINDOWS_H
 
 #include <grpc/support/sync.h>
 
@@ -42,4 +42,4 @@
   int unused;
 } grpc_pollset_kick_state;
 
-#endif  /* __GRPC_INTERNALIOMGR_POLLSET_KICK_WINDOWS_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_WINDOWS_H */
diff --git a/src/core/iomgr/pollset_posix.h b/src/core/iomgr/pollset_posix.h
index 86b6c9f..da843f7 100644
--- a/src/core/iomgr/pollset_posix.h
+++ b/src/core/iomgr/pollset_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_POSIX_H_
-#define __GRPC_INTERNAL_IOMGR_POLLSET_POSIX_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 
 #include <grpc/support/sync.h>
 
@@ -104,4 +104,4 @@
 void grpc_platform_become_multipoller(grpc_pollset *pollset,
                                       struct grpc_fd **fds, size_t fd_count);
 
-#endif /* __GRPC_INTERNAL_IOMGR_POLLSET_POSIX_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H */
diff --git a/src/core/iomgr/pollset_windows.h b/src/core/iomgr/pollset_windows.h
index 41c193f..266175a 100644
--- a/src/core/iomgr/pollset_windows.h
+++ b/src/core/iomgr/pollset_windows.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_WINDOWS_H_
-#define __GRPC_INTERNAL_IOMGR_POLLSET_WINDOWS_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_WINDOWS_H
+#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_WINDOWS_H
 
 #include <windows.h>
 #include <grpc/support/sync.h>
@@ -53,4 +53,4 @@
 #define GRPC_POLLSET_MU(pollset) (&(pollset)->mu)
 #define GRPC_POLLSET_CV(pollset) (&(pollset)->cv)
 
-#endif /* __GRPC_INTERNAL_IOMGR_POLLSET_WINDOWS_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_WINDOWS_H */
diff --git a/src/core/iomgr/resolve_address.h b/src/core/iomgr/resolve_address.h
index 65432ec..8f1d7a2 100644
--- a/src/core/iomgr/resolve_address.h
+++ b/src/core/iomgr/resolve_address.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_RESOLVE_ADDRESS_H__
-#define __GRPC_INTERNAL_IOMGR_RESOLVE_ADDRESS_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_RESOLVE_ADDRESS_H
+#define GRPC_INTERNAL_CORE_IOMGR_RESOLVE_ADDRESS_H
 
 #include <stddef.h>
 
@@ -66,4 +66,4 @@
 grpc_resolved_addresses *grpc_blocking_resolve_address(
     const char *addr, const char *default_port);
 
-#endif /* __GRPC_INTERNAL_IOMGR_RESOLVE_ADDRESS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_RESOLVE_ADDRESS_H */
diff --git a/src/core/iomgr/sockaddr.h b/src/core/iomgr/sockaddr.h
index a5f7c54..7528db7 100644
--- a/src/core/iomgr/sockaddr.h
+++ b/src/core/iomgr/sockaddr.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_SOCKADDR_H_
-#define __GRPC_INTERNAL_IOMGR_SOCKADDR_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_H
 
 #include <grpc/support/port_platform.h>
 
@@ -44,4 +44,4 @@
 #include "src/core/iomgr/sockaddr_posix.h"
 #endif
 
-#endif /* __GRPC_INTERNAL_IOMGR_SOCKADDR_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_H */
diff --git a/src/core/iomgr/sockaddr_posix.h b/src/core/iomgr/sockaddr_posix.h
index 00115e2..2a3d932 100644
--- a/src/core/iomgr/sockaddr_posix.h
+++ b/src/core/iomgr/sockaddr_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_SOCKADDR_POSIX_H_
-#define __GRPC_INTERNAL_IOMGR_SOCKADDR_POSIX_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_POSIX_H
 
 #include <arpa/inet.h>
 #include <sys/socket.h>
@@ -41,4 +41,4 @@
 #include <netdb.h>
 #include <unistd.h>
 
-#endif /* __GRPC_INTERNAL_IOMGR_SOCKADDR_POSIX_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_POSIX_H */
diff --git a/src/core/iomgr/sockaddr_utils.h b/src/core/iomgr/sockaddr_utils.h
index d3a25ad..bdfb834 100644
--- a/src/core/iomgr/sockaddr_utils.h
+++ b/src/core/iomgr/sockaddr_utils.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_SOCKADDR_UTILS_H__
-#define __GRPC_INTERNAL_IOMGR_SOCKADDR_UTILS_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_UTILS_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_UTILS_H
 
 #include "src/core/iomgr/sockaddr.h"
 
@@ -84,4 +84,4 @@
 int grpc_sockaddr_to_string(char **out, const struct sockaddr *addr,
                             int normalize);
 
-#endif /* __GRPC_INTERNAL_IOMGR_SOCKADDR_UTILS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_UTILS_H */
diff --git a/src/core/iomgr/sockaddr_win32.h b/src/core/iomgr/sockaddr_win32.h
index 6ed164c..3a5f27b 100644
--- a/src/core/iomgr/sockaddr_win32.h
+++ b/src/core/iomgr/sockaddr_win32.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_SOCKADDR_WIN32_H_
-#define __GRPC_INTERNAL_IOMGR_SOCKADDR_WIN32_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_WIN32_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_WIN32_H
 
 #include <ws2tcpip.h>
 #include <winsock2.h>
 #include <mswsock.h>
 
-#endif  /* __GRPC_INTERNAL_IOMGR_SOCKADDR_WIN32_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_WIN32_H */
diff --git a/src/core/iomgr/socket_utils_posix.h b/src/core/iomgr/socket_utils_posix.h
index b35fe78..c161082 100644
--- a/src/core/iomgr/socket_utils_posix.h
+++ b/src/core/iomgr/socket_utils_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_SOCKET_UTILS_POSIX_H__
-#define __GRPC_INTERNAL_IOMGR_SOCKET_UTILS_POSIX_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H
 
 #include <unistd.h>
 #include <sys/socket.h>
@@ -105,4 +105,4 @@
 int grpc_create_dualstack_socket(const struct sockaddr *addr, int type,
                                  int protocol, grpc_dualstack_mode *dsmode);
 
-#endif /* __GRPC_INTERNAL_IOMGR_SOCKET_UTILS_POSIX_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H */
diff --git a/src/core/iomgr/socket_windows.h b/src/core/iomgr/socket_windows.h
index de80e97..d4776ab 100644
--- a/src/core/iomgr/socket_windows.h
+++ b/src/core/iomgr/socket_windows.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_HANDLE_WINDOWS_H__
-#define __GRPC_INTERNAL_IOMGR_HANDLE_WINDOWS_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKET_WINDOWS_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKET_WINDOWS_H
 
 #include <windows.h>
 
@@ -72,4 +72,4 @@
 void grpc_winsocket_shutdown(grpc_winsocket *socket);
 void grpc_winsocket_orphan(grpc_winsocket *socket);
 
-#endif /* __GRPC_INTERNAL_IOMGR_HANDLE_WINDOWS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_WINDOWS_H */
diff --git a/src/core/iomgr/tcp_client.h b/src/core/iomgr/tcp_client.h
index c919c02..2e91497 100644
--- a/src/core/iomgr/tcp_client.h
+++ b/src/core/iomgr/tcp_client.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_TCP_CLIENT_H__
-#define __GRPC_INTERNAL_IOMGR_TCP_CLIENT_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_TCP_CLIENT_H
+#define GRPC_INTERNAL_CORE_IOMGR_TCP_CLIENT_H
 
 #include "src/core/iomgr/endpoint.h"
 #include "src/core/iomgr/sockaddr.h"
@@ -45,4 +45,4 @@
                              void *arg, const struct sockaddr *addr,
                              int addr_len, gpr_timespec deadline);
 
-#endif /* __GRPC_INTERNAL_IOMGR_TCP_CLIENT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_TCP_CLIENT_H */
diff --git a/src/core/iomgr/tcp_posix.h b/src/core/iomgr/tcp_posix.h
index 6ff8770..7e8064b 100644
--- a/src/core/iomgr/tcp_posix.h
+++ b/src/core/iomgr/tcp_posix.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_TCP_POSIX_H__
-#define __GRPC_INTERNAL_IOMGR_TCP_POSIX_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_TCP_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_TCP_POSIX_H
 /*
    Low level TCP "bottom half" implementation, for use by transports built on
    top of a TCP connection.
@@ -53,4 +53,4 @@
    Takes ownership of fd. */
 grpc_endpoint *grpc_tcp_create(grpc_fd *fd, size_t read_slice_size);
 
-#endif /* __GRPC_INTERNAL_IOMGR_TCP_POSIX_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_TCP_POSIX_H */
diff --git a/src/core/iomgr/tcp_server.h b/src/core/iomgr/tcp_server.h
index c1e5f45..68ee85c 100644
--- a/src/core/iomgr/tcp_server.h
+++ b/src/core/iomgr/tcp_server.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_TCP_SERVER_H__
-#define __GRPC_INTERNAL_IOMGR_TCP_SERVER_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_TCP_SERVER_H
+#define GRPC_INTERNAL_CORE_IOMGR_TCP_SERVER_H
 
 #include "src/core/iomgr/endpoint.h"
 
@@ -73,4 +73,4 @@
 
 void grpc_tcp_server_destroy(grpc_tcp_server *server);
 
-#endif /* __GRPC_INTERNAL_IOMGR_TCP_SERVER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_TCP_SERVER_H */
diff --git a/src/core/iomgr/tcp_windows.h b/src/core/iomgr/tcp_windows.h
index 565d42e..4cbc12c 100644
--- a/src/core/iomgr/tcp_windows.h
+++ b/src/core/iomgr/tcp_windows.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_TCP_WINDOWS_H__
-#define __GRPC_INTERNAL_IOMGR_TCP_WINDOWS_H__
+#ifndef GRPC_INTERNAL_CORE_IOMGR_TCP_WINDOWS_H
+#define GRPC_INTERNAL_CORE_IOMGR_TCP_WINDOWS_H
 /*
    Low level TCP "bottom half" implementation, for use by transports built on
    top of a TCP connection.
@@ -54,4 +54,4 @@
 
 int grpc_tcp_prepare_socket(SOCKET sock);
 
-#endif /* __GRPC_INTERNAL_IOMGR_TCP_WINDOWS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_TCP_WINDOWS_H */
diff --git a/src/core/iomgr/time_averaged_stats.h b/src/core/iomgr/time_averaged_stats.h
index e901f3c..13894b2 100644
--- a/src/core/iomgr/time_averaged_stats.h
+++ b/src/core/iomgr/time_averaged_stats.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_TIME_AVERAGED_STATS_H_
-#define __GRPC_INTERNAL_IOMGR_TIME_AVERAGED_STATS_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_TIME_AVERAGED_STATS_H
+#define GRPC_INTERNAL_CORE_IOMGR_TIME_AVERAGED_STATS_H
 
 /* This tracks a time-decaying weighted average.  It works by collecting
    batches of samples and then mixing their average into a time-decaying
@@ -85,4 +85,4 @@
    value. */
 double grpc_time_averaged_stats_update_average(grpc_time_averaged_stats *stats);
 
-#endif /* __GRPC_INTERNAL_IOMGR_TIME_AVERAGED_STATS_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_TIME_AVERAGED_STATS_H */
diff --git a/src/core/iomgr/wakeup_fd_pipe.h b/src/core/iomgr/wakeup_fd_pipe.h
index a2fcde5..aa8f977 100644
--- a/src/core/iomgr/wakeup_fd_pipe.h
+++ b/src/core/iomgr/wakeup_fd_pipe.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_IOMGR_WAKEUP_FD_PIPE_H_
-#define __GRPC_INTERNAL_IOMGR_WAKEUP_FD_PIPE_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_PIPE_H
+#define GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_PIPE_H
 
 #include "src/core/iomgr/wakeup_fd_posix.h"
 
 extern grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable;
 
-#endif  /* __GRPC_INTERNAL_IOMGR_WAKEUP_FD_PIPE_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_PIPE_H */
diff --git a/src/core/iomgr/wakeup_fd_posix.h b/src/core/iomgr/wakeup_fd_posix.h
index 75bb9fc..1b0ff70 100644
--- a/src/core/iomgr/wakeup_fd_posix.h
+++ b/src/core/iomgr/wakeup_fd_posix.h
@@ -59,8 +59,8 @@
  * 2. If the polling thread was awakened by a wakeup_fd event, call
  *    grpc_wakeup_fd_consume_wakeup() on it.
  */
-#ifndef __GRPC_INTERNAL_IOMGR_WAKEUP_FD_POSIX_H_
-#define __GRPC_INTERNAL_IOMGR_WAKEUP_FD_POSIX_H_
+#ifndef GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_POSIX_H
 
 void grpc_wakeup_fd_global_init(void);
 void grpc_wakeup_fd_global_destroy(void);
@@ -96,4 +96,4 @@
  * wakeup_fd_nospecial.c if no such implementation exists. */
 extern const grpc_wakeup_fd_vtable grpc_specialized_wakeup_fd_vtable;
 
-#endif /* __GRPC_INTERNAL_IOMGR_WAKEUP_FD_POSIX_H_ */
+#endif  /* GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_POSIX_H */
diff --git a/src/core/json/json.h b/src/core/json/json.h
index dc519e9..69cbac1 100644
--- a/src/core/json/json.h
+++ b/src/core/json/json.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SRC_CORE_JSON_JSON_H__
-#define __GRPC_SRC_CORE_JSON_JSON_H__
+#ifndef GRPC_INTERNAL_CORE_JSON_JSON_H
+#define GRPC_INTERNAL_CORE_JSON_JSON_H
 
 #include <stdlib.h>
 
@@ -85,4 +85,4 @@
 grpc_json* grpc_json_create(grpc_json_type type);
 void grpc_json_destroy(grpc_json* json);
 
-#endif /* __GRPC_SRC_CORE_JSON_JSON_H__ */
+#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_H */
diff --git a/src/core/json/json_common.h b/src/core/json/json_common.h
index 60763cc..84bf375 100644
--- a/src/core/json/json_common.h
+++ b/src/core/json/json_common.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SRC_CORE_JSON_JSON_COMMON_H__
-#define __GRPC_SRC_CORE_JSON_JSON_COMMON_H__
+#ifndef GRPC_INTERNAL_CORE_JSON_JSON_COMMON_H
+#define GRPC_INTERNAL_CORE_JSON_JSON_COMMON_H
 
 /* The various json types. */
 typedef enum {
@@ -46,4 +46,4 @@
   GRPC_JSON_TOP_LEVEL
 } grpc_json_type;
 
-#endif /* __GRPC_SRC_CORE_JSON_JSON_COMMON_H__ */
+#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_COMMON_H */
diff --git a/src/core/json/json_reader.h b/src/core/json/json_reader.h
index f7f5912..b1a5ace 100644
--- a/src/core/json/json_reader.h
+++ b/src/core/json/json_reader.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SRC_CORE_JSON_JSON_READER_H__
-#define __GRPC_SRC_CORE_JSON_JSON_READER_H__
+#ifndef GRPC_INTERNAL_CORE_JSON_JSON_READER_H
+#define GRPC_INTERNAL_CORE_JSON_JSON_READER_H
 
 #include <grpc/support/port_platform.h>
 #include "src/core/json/json_common.h"
@@ -157,4 +157,4 @@
  */
 int grpc_json_reader_is_complete(grpc_json_reader* reader);
 
-#endif /* __GRPC_SRC_CORE_JSON_JSON_READER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_READER_H */
diff --git a/src/core/json/json_writer.h b/src/core/json/json_writer.h
index 5d5d089..dfa61a5 100644
--- a/src/core/json/json_writer.h
+++ b/src/core/json/json_writer.h
@@ -43,8 +43,8 @@
  * a valid UTF-8 string overall.
  */
 
-#ifndef __GRPC_SRC_CORE_JSON_JSON_WRITER_H__
-#define __GRPC_SRC_CORE_JSON_JSON_WRITER_H__
+#ifndef GRPC_INTERNAL_CORE_JSON_JSON_WRITER_H
+#define GRPC_INTERNAL_CORE_JSON_JSON_WRITER_H
 
 #include <stdlib.h>
 
@@ -90,4 +90,4 @@
 /* Sets a string value. It'll be escaped, and utf-8 validated. */
 void grpc_json_writer_value_string(grpc_json_writer* writer, const char* string);
 
-#endif /* __GRPC_SRC_CORE_JSON_JSON_WRITER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_WRITER_H */
diff --git a/src/core/security/auth.h b/src/core/security/auth.h
index fee75c4..08dc415 100644
--- a/src/core/security/auth.h
+++ b/src/core/security/auth.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SECURITY_AUTH_H__
-#define __GRPC_INTERNAL_SECURITY_AUTH_H__
+#ifndef GRPC_INTERNAL_CORE_SECURITY_AUTH_H
+#define GRPC_INTERNAL_CORE_SECURITY_AUTH_H
 
 #include "src/core/channel/channel_stack.h"
 
 extern const grpc_channel_filter grpc_client_auth_filter;
 
-#endif /* __GRPC_INTERNAL_SECURITY_AUTH_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_AUTH_H */
diff --git a/src/core/security/base64.h b/src/core/security/base64.h
index 0eb69d0..6a7cd8e 100644
--- a/src/core/security/base64.h
+++ b/src/core/security/base64.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SECURITY_BASE64_H_
-#define __GRPC_INTERNAL_SECURITY_BASE64_H_
+#ifndef GRPC_INTERNAL_CORE_SECURITY_BASE64_H
+#define GRPC_INTERNAL_CORE_SECURITY_BASE64_H
 
 #include <grpc/support/slice.h>
 
@@ -45,4 +45,4 @@
    slice in case of failure. */
 gpr_slice grpc_base64_decode(const char *b64, int url_safe);
 
-#endif /* __GRPC_INTERNAL_SECURITY_BASE64_H_ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_BASE64_H */
diff --git a/src/core/security/credentials.h b/src/core/security/credentials.h
index 0a0074c..454e668 100644
--- a/src/core/security/credentials.h
+++ b/src/core/security/credentials.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SECURITY_CREDENTIALS_H__
-#define __GRPC_INTERNAL_SECURITY_CREDENTIALS_H__
+#ifndef GRPC_INTERNAL_CORE_SECURITY_CREDENTIALS_H
+#define GRPC_INTERNAL_CORE_SECURITY_CREDENTIALS_H
 
 #include "src/core/transport/stream_op.h"
 #include <grpc/grpc.h>
@@ -160,4 +160,4 @@
 const grpc_ssl_server_config *grpc_ssl_server_credentials_get_config(
     const grpc_server_credentials *ssl_creds);
 
-#endif /* __GRPC_INTERNAL_SECURITY_CREDENTIALS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_CREDENTIALS_H */
diff --git a/src/core/security/json_token.h b/src/core/security/json_token.h
index 1ef9682..029ede3 100644
--- a/src/core/security/json_token.h
+++ b/src/core/security/json_token.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SECURITY_JSON_TOKEN_H_
-#define __GRPC_INTERNAL_SECURITY_JSON_TOKEN_H_
+#ifndef GRPC_INTERNAL_CORE_SECURITY_JSON_TOKEN_H
+#define GRPC_INTERNAL_CORE_SECURITY_JSON_TOKEN_H
 
 #include <grpc/support/slice.h>
 #include <openssl/rsa.h>
@@ -79,4 +79,4 @@
 void grpc_jwt_encode_and_sign_set_override(
     grpc_jwt_encode_and_sign_override func);
 
-#endif /* __GRPC_INTERNAL_SECURITY_JSON_TOKEN_H_ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_JSON_TOKEN_H */
diff --git a/src/core/security/secure_endpoint.h b/src/core/security/secure_endpoint.h
index 82ba408..808889b 100644
--- a/src/core/security/secure_endpoint.h
+++ b/src/core/security/secure_endpoint.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_ENDPOINT_SECURE_ENDPOINT_H__
-#define __GRPC_INTERNAL_ENDPOINT_SECURE_ENDPOINT_H__
+#ifndef GRPC_INTERNAL_CORE_SECURITY_SECURE_ENDPOINT_H
+#define GRPC_INTERNAL_CORE_SECURITY_SECURE_ENDPOINT_H
 
 #include "src/core/iomgr/endpoint.h"
 #include <grpc/support/slice.h>
@@ -44,4 +44,4 @@
     struct tsi_frame_protector *protector, grpc_endpoint *to_wrap,
     gpr_slice *leftover_slices, size_t leftover_nslices);
 
-#endif /* __GRPC_INTERNAL_ENDPOINT_SECURE_ENDPOINT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_SECURE_ENDPOINT_H */
diff --git a/src/core/security/secure_transport_setup.h b/src/core/security/secure_transport_setup.h
index 21f41fd..e1f8ed7 100644
--- a/src/core/security/secure_transport_setup.h
+++ b/src/core/security/secure_transport_setup.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SECURITY_SECURE_TRANSPORT_SETUP_H__
-#define __GRPC_INTERNAL_SECURITY_SECURE_TRANSPORT_SETUP_H__
+#ifndef GRPC_INTERNAL_CORE_SECURITY_SECURE_TRANSPORT_SETUP_H
+#define GRPC_INTERNAL_CORE_SECURITY_SECURE_TRANSPORT_SETUP_H
 
 #include "src/core/iomgr/endpoint.h"
 #include "src/core/security/security_context.h"
@@ -50,4 +50,4 @@
                                  grpc_secure_transport_setup_done_cb cb,
                                  void *user_data);
 
-#endif /* __GRPC_INTERNAL_SECURITY_SECURE_TRANSPORT_SETUP_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_SECURE_TRANSPORT_SETUP_H */
diff --git a/src/core/security/security_context.h b/src/core/security/security_context.h
index 40e2dac..0b5821c 100644
--- a/src/core/security/security_context.h
+++ b/src/core/security/security_context.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SECURITY_SECURITY_CONTEXT_H__
-#define __GRPC_INTERNAL_SECURITY_SECURITY_CONTEXT_H__
+#ifndef GRPC_INTERNAL_CORE_SECURITY_SECURITY_CONTEXT_H
+#define GRPC_INTERNAL_CORE_SECURITY_SECURITY_CONTEXT_H
 
 #include <grpc/grpc_security.h>
 #include "src/core/iomgr/endpoint.h"
@@ -212,4 +212,4 @@
                                                 const grpc_channel_args *args,
                                                 grpc_security_context *ctx);
 
-#endif /* __GRPC_INTERNAL_SECURITY_SECURITY_CONTEXT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SECURITY_SECURITY_CONTEXT_H */
diff --git a/src/core/statistics/census_interface.h b/src/core/statistics/census_interface.h
index 0bb0a9f..eb4349c 100644
--- a/src/core/statistics/census_interface.h
+++ b/src/core/statistics/census_interface.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_STATISTICS_CENSUS_INTERFACE_H__
-#define __GRPC_INTERNAL_STATISTICS_CENSUS_INTERFACE_H__
+#ifndef GRPC_INTERNAL_CORE_STATISTICS_CENSUS_INTERFACE_H
+#define GRPC_INTERNAL_CORE_STATISTICS_CENSUS_INTERFACE_H
 
 #include <grpc/support/port_platform.h>
 
@@ -73,4 +73,4 @@
 /* Ends tracing. Calling this function will invalidate the input op_id. */
 void census_tracing_end_op(census_op_id op_id);
 
-#endif /* __GRPC_INTERNAL_STATISTICS_CENSUS_INTERFACE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_INTERFACE_H */
diff --git a/src/core/statistics/census_log.h b/src/core/statistics/census_log.h
index 01fd63a..06869b7 100644
--- a/src/core/statistics/census_log.h
+++ b/src/core/statistics/census_log.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_STATISTICS_LOG_H__
-#define __GRPC_INTERNAL_STATISTICS_LOG_H__
+#ifndef GRPC_INTERNAL_CORE_STATISTICS_CENSUS_LOG_H
+#define GRPC_INTERNAL_CORE_STATISTICS_CENSUS_LOG_H
 
 #include <stddef.h>
 
@@ -88,4 +88,4 @@
    out-of-space. */
 int census_log_out_of_space_count(void);
 
-#endif /* __GRPC_INTERNAL_STATISTICS_LOG_H__ */
+#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_LOG_H */
diff --git a/src/core/statistics/census_rpc_stats.h b/src/core/statistics/census_rpc_stats.h
index 942de81..9336dce 100644
--- a/src/core/statistics/census_rpc_stats.h
+++ b/src/core/statistics/census_rpc_stats.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_STATISTICS_CENSUS_RPC_STATS_H__
-#define __GRPC_INTERNAL_STATISTICS_CENSUS_RPC_STATS_H__
+#ifndef GRPC_INTERNAL_CORE_STATISTICS_CENSUS_RPC_STATS_H
+#define GRPC_INTERNAL_CORE_STATISTICS_CENSUS_RPC_STATS_H
 
 #include "src/core/statistics/census_interface.h"
 #include <grpc/support/port_platform.h>
@@ -98,4 +98,4 @@
 }
 #endif
 
-#endif /* __GRPC_INTERNAL_STATISTICS_CENSUS_RPC_STATS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_RPC_STATS_H */
diff --git a/src/core/statistics/census_tracing.h b/src/core/statistics/census_tracing.h
index 51aa578..a4494b5 100644
--- a/src/core/statistics/census_tracing.h
+++ b/src/core/statistics/census_tracing.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_STATISTICS_CENSUS_TRACING_H_
-#define __GRPC_INTERNAL_STATISTICS_CENSUS_TRACING_H_
+#ifndef GRPC_INTERNAL_CORE_STATISTICS_CENSUS_TRACING_H
+#define GRPC_INTERNAL_CORE_STATISTICS_CENSUS_TRACING_H
 
 #include <grpc/support/time.h>
 #include "src/core/statistics/census_rpc_stats.h"
@@ -93,4 +93,4 @@
 }
 #endif
 
-#endif /* __GRPC_INTERNAL_STATISTICS_CENSUS_TRACING_H_ */
+#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_TRACING_H */
diff --git a/src/core/statistics/hash_table.h b/src/core/statistics/hash_table.h
index 2c2386d..7bcb4bc 100644
--- a/src/core/statistics/hash_table.h
+++ b/src/core/statistics/hash_table.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_STATISTICS_HASH_TABLE_H_
-#define __GRPC_INTERNAL_STATISTICS_HASH_TABLE_H_
+#ifndef GRPC_INTERNAL_CORE_STATISTICS_HASH_TABLE_H
+#define GRPC_INTERNAL_CORE_STATISTICS_HASH_TABLE_H
 
 #include <stddef.h>
 
@@ -128,4 +128,4 @@
    should not invalidate data entries. */
 gpr_uint64 census_ht_for_all(const census_ht* ht, census_ht_itr_cb);
 
-#endif /* __GRPC_INTERNAL_STATISTICS_HASH_TABLE_H_ */
+#endif  /* GRPC_INTERNAL_CORE_STATISTICS_HASH_TABLE_H */
diff --git a/src/core/statistics/window_stats.h b/src/core/statistics/window_stats.h
index 98f8dac..d733d8d 100644
--- a/src/core/statistics/window_stats.h
+++ b/src/core/statistics/window_stats.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_STATISTICS_WINDOW_STATS_H_
-#define __GRPC_INTERNAL_STATISTICS_WINDOW_STATS_H_
+#ifndef GRPC_INTERNAL_CORE_STATISTICS_WINDOW_STATS_H
+#define GRPC_INTERNAL_CORE_STATISTICS_WINDOW_STATS_H
 
 #include <grpc/support/time.h>
 
@@ -170,4 +170,4 @@
    assertion failure). This function is thread-compatible. */
 void census_window_stats_destroy(struct census_window_stats* wstats);
 
-#endif /* __GRPC_INTERNAL_STATISTICS_WINDOW_STATS_H_ */
+#endif  /* GRPC_INTERNAL_CORE_STATISTICS_WINDOW_STATS_H */
diff --git a/src/core/support/env.h b/src/core/support/env.h
index 0c6091b..4f2e394 100644
--- a/src/core/support/env.h
+++ b/src/core/support/env.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_ENV_H__
-#define __GRPC_SUPPORT_ENV_H__
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_ENV_H
+#define GRPC_INTERNAL_CORE_SUPPORT_ENV_H
 
 #include <stdio.h>
 
@@ -57,4 +57,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_ENV_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SUPPORT_ENV_H */
diff --git a/src/core/support/file.h b/src/core/support/file.h
index 600850e..ee6ca7b 100644
--- a/src/core/support/file.h
+++ b/src/core/support/file.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_FILE_H__
-#define __GRPC_SUPPORT_FILE_H__
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_FILE_H
+#define GRPC_INTERNAL_CORE_SUPPORT_FILE_H
 
 #include <stdio.h>
 
@@ -58,4 +58,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_FILE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SUPPORT_FILE_H */
diff --git a/src/core/support/murmur_hash.h b/src/core/support/murmur_hash.h
index 06c0c56..85ab2fe 100644
--- a/src/core/support/murmur_hash.h
+++ b/src/core/support/murmur_hash.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SUPPORT_MURMUR_HASH_H__
-#define __GRPC_INTERNAL_SUPPORT_MURMUR_HASH_H__
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_MURMUR_HASH_H
+#define GRPC_INTERNAL_CORE_SUPPORT_MURMUR_HASH_H
 
 #include <grpc/support/port_platform.h>
 
@@ -41,4 +41,4 @@
 /* compute the hash of key (length len) */
 gpr_uint32 gpr_murmur_hash3(const void *key, size_t len, gpr_uint32 seed);
 
-#endif /* __GRPC_INTERNAL_SUPPORT_MURMUR_HASH_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SUPPORT_MURMUR_HASH_H */
diff --git a/src/core/support/string.h b/src/core/support/string.h
index eaa1826..faf3342 100644
--- a/src/core/support/string.h
+++ b/src/core/support/string.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_STRING_H__
-#define __GRPC_SUPPORT_STRING_H__
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_STRING_H
+#define GRPC_INTERNAL_CORE_SUPPORT_STRING_H
 
 #include <stddef.h>
 
@@ -106,4 +106,4 @@
 }
 #endif
 
-#endif /* __GRPC_SUPPORT_STRING_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SUPPORT_STRING_H */
diff --git a/src/core/support/string_win32.h b/src/core/support/string_win32.h
index 5dbb40d..0bc3247 100644
--- a/src/core/support/string_win32.h
+++ b/src/core/support/string_win32.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_SUPPORT_STRING_WIN32_H__
-#define __GRPC_SUPPORT_STRING_WIN32_H__
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_STRING_WIN32_H
+#define GRPC_INTERNAL_CORE_SUPPORT_STRING_WIN32_H
 
 #include <grpc/support/port_platform.h>
 
@@ -46,4 +46,4 @@
 
 #endif  /* GPR_WIN32 */
 
-#endif /* __GRPC_SUPPORT_STRING_WIN32_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SUPPORT_STRING_WIN32_H */
diff --git a/src/core/support/thd_internal.h b/src/core/support/thd_internal.h
index 0fb1447..4683c37 100644
--- a/src/core/support/thd_internal.h
+++ b/src/core/support/thd_internal.h
@@ -31,9 +31,9 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SUPPORT_THD_INTERNAL_H__
-#define __GRPC_INTERNAL_SUPPORT_THD_INTERNAL_H__
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_THD_INTERNAL_H
+#define GRPC_INTERNAL_CORE_SUPPORT_THD_INTERNAL_H
 
 /* Internal interfaces between modules within the gpr support library.  */
 
-#endif /* __GRPC_INTERNAL_SUPPORT_THD_INTERNAL_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SUPPORT_THD_INTERNAL_H */
diff --git a/src/core/surface/byte_buffer_queue.h b/src/core/surface/byte_buffer_queue.h
index 9d3b525..32c57f8 100644
--- a/src/core/surface/byte_buffer_queue.h
+++ b/src/core/surface/byte_buffer_queue.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_BYTE_BUFFER_QUEUE_H__
-#define __GRPC_INTERNAL_SURFACE_BYTE_BUFFER_QUEUE_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_BYTE_BUFFER_QUEUE_H
+#define GRPC_INTERNAL_CORE_SURFACE_BYTE_BUFFER_QUEUE_H
 
 #include <grpc/byte_buffer.h>
 
@@ -57,4 +57,4 @@
 int grpc_bbq_empty(grpc_byte_buffer_queue *q);
 void grpc_bbq_push(grpc_byte_buffer_queue *q, grpc_byte_buffer *bb);
 
-#endif  /* __GRPC_INTERNAL_SURFACE_BYTE_BUFFER_QUEUE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_BYTE_BUFFER_QUEUE_H */
diff --git a/src/core/surface/call.h b/src/core/surface/call.h
index dd3ad12..cb81cb5 100644
--- a/src/core/surface/call.h
+++ b/src/core/surface/call.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_CALL_H__
-#define __GRPC_INTERNAL_SURFACE_CALL_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_CALL_H
+#define GRPC_INTERNAL_CORE_SURFACE_CALL_H
 
 #include "src/core/channel/channel_stack.h"
 #include "src/core/channel/metadata_buffer.h"
@@ -119,4 +119,4 @@
 /* Given the top call_element, get the call object. */
 grpc_call *grpc_call_from_top_element(grpc_call_element *surface_element);
 
-#endif /* __GRPC_INTERNAL_SURFACE_CALL_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_CALL_H */
diff --git a/src/core/surface/channel.h b/src/core/surface/channel.h
index 6bdfd47..d3e5118 100644
--- a/src/core/surface/channel.h
+++ b/src/core/surface/channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_CHANNEL_H__
-#define __GRPC_INTERNAL_SURFACE_CHANNEL_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_CHANNEL_H
+#define GRPC_INTERNAL_CORE_SURFACE_CHANNEL_H
 
 #include "src/core/channel/channel_stack.h"
 
@@ -50,4 +50,4 @@
 void grpc_channel_internal_ref(grpc_channel *channel);
 void grpc_channel_internal_unref(grpc_channel *channel);
 
-#endif /* __GRPC_INTERNAL_SURFACE_CHANNEL_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_CHANNEL_H */
diff --git a/src/core/surface/client.h b/src/core/surface/client.h
index 06ce8f6..9db2ccf 100644
--- a/src/core/surface/client.h
+++ b/src/core/surface/client.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_CLIENT_H__
-#define __GRPC_INTERNAL_SURFACE_CLIENT_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_CLIENT_H
+#define GRPC_INTERNAL_CORE_SURFACE_CLIENT_H
 
 #include "src/core/channel/channel_stack.h"
 
 extern const grpc_channel_filter grpc_client_surface_filter;
 
-#endif /* __GRPC_INTERNAL_SURFACE_CLIENT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_CLIENT_H */
diff --git a/src/core/surface/completion_queue.h b/src/core/surface/completion_queue.h
index a7688b8..3054264 100644
--- a/src/core/surface/completion_queue.h
+++ b/src/core/surface/completion_queue.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_COMPLETION_QUEUE_H__
-#define __GRPC_INTERNAL_SURFACE_COMPLETION_QUEUE_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_COMPLETION_QUEUE_H
+#define GRPC_INTERNAL_CORE_SURFACE_COMPLETION_QUEUE_H
 
 /* Internal API for completion channels */
 
@@ -114,4 +114,4 @@
 
 grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc);
 
-#endif /* __GRPC_INTERNAL_SURFACE_COMPLETION_QUEUE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_COMPLETION_QUEUE_H */
diff --git a/src/core/surface/event_string.h b/src/core/surface/event_string.h
index d9b1e4e..e8a8f93 100644
--- a/src/core/surface/event_string.h
+++ b/src/core/surface/event_string.h
@@ -31,12 +31,12 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_EVENT_STRING_H__
-#define __GRPC_INTERNAL_SURFACE_EVENT_STRING_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_EVENT_STRING_H
+#define GRPC_INTERNAL_CORE_SURFACE_EVENT_STRING_H
 
 #include <grpc/grpc.h>
 
 /* Returns a string describing an event. Must be later freed with gpr_free() */
 char *grpc_event_string(grpc_event *ev);
 
-#endif /* __GRPC_INTERNAL_SURFACE_EVENT_STRING_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_EVENT_STRING_H */
diff --git a/src/core/surface/lame_client.h b/src/core/surface/lame_client.h
index 2bd97b9..b13e8cb 100644
--- a/src/core/surface/lame_client.h
+++ b/src/core/surface/lame_client.h
@@ -31,12 +31,12 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_LAME_CLIENT_H_
-#define __GRPC_INTERNAL_SURFACE_LAME_CLIENT_H_
+#ifndef GRPC_INTERNAL_CORE_SURFACE_LAME_CLIENT_H
+#define GRPC_INTERNAL_CORE_SURFACE_LAME_CLIENT_H
 
 #include <grpc/grpc.h>
 
 /* Create a lame client: this client fails every operation attempted on it. */
 grpc_channel *grpc_lame_client_channel_create(void);
 
-#endif /* __GRPC_INTERNAL_SURFACE_LAME_CLIENT_H_ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_LAME_CLIENT_H */
diff --git a/src/core/surface/server.h b/src/core/surface/server.h
index 5ae59b2..e33f69b 100644
--- a/src/core/surface/server.h
+++ b/src/core/surface/server.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_SERVER_H__
-#define __GRPC_INTERNAL_SURFACE_SERVER_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_SERVER_H
+#define GRPC_INTERNAL_CORE_SURFACE_SERVER_H
 
 #include "src/core/channel/channel_stack.h"
 #include <grpc/grpc.h>
@@ -60,4 +60,4 @@
 
 const grpc_channel_args *grpc_server_get_channel_args(grpc_server *server);
 
-#endif /* __GRPC_INTERNAL_SURFACE_SERVER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_SERVER_H */
diff --git a/src/core/surface/surface_trace.h b/src/core/surface/surface_trace.h
index 4d478d6..50071ee 100644
--- a/src/core/surface/surface_trace.h
+++ b/src/core/surface/surface_trace.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_SURFACE_SURFACE_TRACE_H__
-#define __GRPC_INTERNAL_SURFACE_SURFACE_TRACE_H__
+#ifndef GRPC_INTERNAL_CORE_SURFACE_SURFACE_TRACE_H
+#define GRPC_INTERNAL_CORE_SURFACE_SURFACE_TRACE_H
 
 #include "src/core/debug/trace.h"
 #include <grpc/support/log.h>
@@ -44,4 +44,4 @@
     gpr_free(_ev);                                      \
   }
 
-#endif /* __GRPC_INTERNAL_SURFACE_SURFACE_TRACE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_SURFACE_SURFACE_TRACE_H */
diff --git a/src/core/transport/chttp2/alpn.h b/src/core/transport/chttp2/alpn.h
index 796f514..fcbefc0 100644
--- a/src/core/transport/chttp2/alpn.h
+++ b/src/core/transport/chttp2/alpn.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_ALPN_H_
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_ALPN_H_
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_ALPN_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_ALPN_H
 
 #include <string.h>
 
@@ -46,4 +46,4 @@
  * grpc_chttp2_num_alpn_versions()) */
 const char *grpc_chttp2_get_alpn_version_index(size_t i);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_ALPN_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_ALPN_H */
diff --git a/src/core/transport/chttp2/bin_encoder.h b/src/core/transport/chttp2/bin_encoder.h
index 2368fdd..9c88ac9 100644
--- a/src/core/transport/chttp2/bin_encoder.h
+++ b/src/core/transport/chttp2/bin_encoder.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_BIN_ENCODER_H_
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_BIN_ENCODER_H_
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_BIN_ENCODER_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_BIN_ENCODER_H
 
 #include <grpc/support/slice.h>
 
@@ -53,4 +53,4 @@
 
 int grpc_is_binary_header(const char *key, size_t length);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_BIN_ENCODER_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_BIN_ENCODER_H */
diff --git a/src/core/transport/chttp2/frame.h b/src/core/transport/chttp2/frame.h
index 733dd5e..fbb9419 100644
--- a/src/core/transport/chttp2/frame.h
+++ b/src/core/transport/chttp2/frame.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_H
 
 #include <grpc/support/port_platform.h>
 #include <grpc/support/slice.h>
@@ -77,4 +77,4 @@
 #define GRPC_CHTTP2_DATA_FLAG_PADDED 8
 #define GRPC_CHTTP2_FLAG_HAS_PRIORITY 0x20
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_H */
diff --git a/src/core/transport/chttp2/frame_data.h b/src/core/transport/chttp2/frame_data.h
index 4d05a5f..24e557a 100644
--- a/src/core/transport/chttp2/frame_data.h
+++ b/src/core/transport/chttp2/frame_data.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_DATA_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_DATA_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_DATA_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_DATA_H
 
 /* Parser for GRPC streams embedded in DATA frames */
 
@@ -77,4 +77,4 @@
 /* create a slice with an empty data frame and is_last set */
 gpr_slice grpc_chttp2_data_frame_create_empty_close(gpr_uint32 id);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_DATA_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_DATA_H */
diff --git a/src/core/transport/chttp2/frame_goaway.h b/src/core/transport/chttp2/frame_goaway.h
index 9ccef27..7638891 100644
--- a/src/core/transport/chttp2/frame_goaway.h
+++ b/src/core/transport/chttp2/frame_goaway.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_GOAWAY_H_
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_GOAWAY_H_
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_GOAWAY_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_GOAWAY_H
 
 #include "src/core/transport/chttp2/frame.h"
 #include <grpc/support/port_platform.h>
@@ -71,4 +71,4 @@
                                gpr_slice debug_data,
                                gpr_slice_buffer *slice_buffer);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_GOAWAY_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_GOAWAY_H */
diff --git a/src/core/transport/chttp2/frame_ping.h b/src/core/transport/chttp2/frame_ping.h
index d9d6f7e..11d38b8 100644
--- a/src/core/transport/chttp2/frame_ping.h
+++ b/src/core/transport/chttp2/frame_ping.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_PING_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_PING_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_PING_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_PING_H
 
 #include <grpc/support/slice.h>
 #include "src/core/transport/chttp2/frame.h"
@@ -50,4 +50,4 @@
 grpc_chttp2_parse_error grpc_chttp2_ping_parser_parse(
     void *parser, grpc_chttp2_parse_state *state, gpr_slice slice, int is_last);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_PING_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_PING_H */
diff --git a/src/core/transport/chttp2/frame_rst_stream.h b/src/core/transport/chttp2/frame_rst_stream.h
index 83fc380..2d3ee18 100644
--- a/src/core/transport/chttp2/frame_rst_stream.h
+++ b/src/core/transport/chttp2/frame_rst_stream.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_RST_STREAM_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_RST_STREAM_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_RST_STREAM_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_RST_STREAM_H
 
 #include <grpc/support/slice.h>
 
 gpr_slice grpc_chttp2_rst_stream_create(gpr_uint32 stream_id, gpr_uint32 code);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_RST_STREAM_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_RST_STREAM_H */
diff --git a/src/core/transport/chttp2/frame_settings.h b/src/core/transport/chttp2/frame_settings.h
index 6cde2c6..1876563 100644
--- a/src/core/transport/chttp2/frame_settings.h
+++ b/src/core/transport/chttp2/frame_settings.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_SETTINGS_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_SETTINGS_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_SETTINGS_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_SETTINGS_H
 
 #include <grpc/support/port_platform.h>
 #include <grpc/support/slice.h>
@@ -96,4 +96,4 @@
 grpc_chttp2_parse_error grpc_chttp2_settings_parser_parse(
     void *parser, grpc_chttp2_parse_state *state, gpr_slice slice, int is_last);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_SETTINGS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_SETTINGS_H */
diff --git a/src/core/transport/chttp2/frame_window_update.h b/src/core/transport/chttp2/frame_window_update.h
index 093263d..85475a8 100644
--- a/src/core/transport/chttp2/frame_window_update.h
+++ b/src/core/transport/chttp2/frame_window_update.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_WINDOW_UPDATE_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_WINDOW_UPDATE_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_WINDOW_UPDATE_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_WINDOW_UPDATE_H
 
 #include <grpc/support/slice.h>
 #include "src/core/transport/chttp2/frame.h"
@@ -52,4 +52,4 @@
 grpc_chttp2_parse_error grpc_chttp2_window_update_parser_parse(
     void *parser, grpc_chttp2_parse_state *state, gpr_slice slice, int is_last);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_FRAME_WINDOW_UPDATE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_FRAME_WINDOW_UPDATE_H */
diff --git a/src/core/transport/chttp2/hpack_parser.h b/src/core/transport/chttp2/hpack_parser.h
index 94acc88..bb4c1a1 100644
--- a/src/core/transport/chttp2/hpack_parser.h
+++ b/src/core/transport/chttp2/hpack_parser.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_HPACK_PARSER_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_HPACK_PARSER_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_PARSER_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_PARSER_H
 
 #include <stddef.h>
 
@@ -108,4 +108,4 @@
     void *hpack_parser, grpc_chttp2_parse_state *state, gpr_slice slice,
     int is_last);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_HPACK_PARSER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_PARSER_H */
diff --git a/src/core/transport/chttp2/hpack_table.h b/src/core/transport/chttp2/hpack_table.h
index ea0fc1d..d3bf41b 100644
--- a/src/core/transport/chttp2/hpack_table.h
+++ b/src/core/transport/chttp2/hpack_table.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_HPACK_TABLE_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_HPACK_TABLE_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_TABLE_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_TABLE_H
 
 #include "src/core/transport/metadata.h"
 #include <grpc/support/port_platform.h>
@@ -94,4 +94,4 @@
 grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
     const grpc_chttp2_hptbl *tbl, grpc_mdelem *md);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_HPACK_TABLE_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_TABLE_H */
diff --git a/src/core/transport/chttp2/http2_errors.h b/src/core/transport/chttp2/http2_errors.h
index 1eecd17..4ab2ec0 100644
--- a/src/core/transport/chttp2/http2_errors.h
+++ b/src/core/transport/chttp2/http2_errors.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_HTTP2_ERRORS_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_HTTP2_ERRORS_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HTTP2_ERRORS_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HTTP2_ERRORS_H
 
 /* error codes for RST_STREAM from http2 draft 14 section 7 */
 typedef enum {
@@ -53,4 +53,4 @@
   GRPC_CHTTP2__ERROR_DO_NOT_USE = -1
 } grpc_chttp2_error_code;
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_HTTP2_ERRORS_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HTTP2_ERRORS_H */
diff --git a/src/core/transport/chttp2/huffsyms.h b/src/core/transport/chttp2/huffsyms.h
index 131c4ac..f9c1447 100644
--- a/src/core/transport/chttp2/huffsyms.h
+++ b/src/core/transport/chttp2/huffsyms.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_HUFFSYMS_H_
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_HUFFSYMS_H_
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HUFFSYMS_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HUFFSYMS_H
 
 /* HPACK static huffman table */
 
@@ -45,4 +45,4 @@
 
 extern const grpc_chttp2_huffsym grpc_chttp2_huffsyms[GRPC_CHTTP2_NUM_HUFFSYMS];
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_HUFFSYMS_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HUFFSYMS_H */
diff --git a/src/core/transport/chttp2/status_conversion.h b/src/core/transport/chttp2/status_conversion.h
index 8e26720..cf06c35 100644
--- a/src/core/transport/chttp2/status_conversion.h
+++ b/src/core/transport/chttp2/status_conversion.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_STATUS_CONVERSION_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_STATUS_CONVERSION_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STATUS_CONVERSION_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STATUS_CONVERSION_H
 
 #include <grpc/grpc.h>
 #include "src/core/transport/chttp2/http2_errors.h"
@@ -47,4 +47,4 @@
 grpc_status_code grpc_chttp2_http2_status_to_grpc_status(int status);
 int grpc_chttp2_grpc_status_to_http2_status(grpc_status_code status);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_STATUS_CONVERSION_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STATUS_CONVERSION_H */
diff --git a/src/core/transport/chttp2/stream_encoder.h b/src/core/transport/chttp2/stream_encoder.h
index a99d61a..50c58ad 100644
--- a/src/core/transport/chttp2/stream_encoder.h
+++ b/src/core/transport/chttp2/stream_encoder.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_STREAM_ENCODER_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_STREAM_ENCODER_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STREAM_ENCODER_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STREAM_ENCODER_H
 
 #include "src/core/transport/chttp2/frame.h"
 #include "src/core/transport/metadata.h"
@@ -90,4 +90,4 @@
                         grpc_chttp2_hpack_compressor *compressor,
                         gpr_slice_buffer *output);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_STREAM_ENCODER_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STREAM_ENCODER_H */
diff --git a/src/core/transport/chttp2/stream_map.h b/src/core/transport/chttp2/stream_map.h
index 3fb91fc..d338d2f 100644
--- a/src/core/transport/chttp2/stream_map.h
+++ b/src/core/transport/chttp2/stream_map.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_STREAM_MAP_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_STREAM_MAP_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STREAM_MAP_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STREAM_MAP_H
 
 #include <grpc/support/port_platform.h>
 
@@ -78,4 +78,4 @@
                                                void *value),
                                      void *user_data);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_STREAM_MAP_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_STREAM_MAP_H */
diff --git a/src/core/transport/chttp2/timeout_encoding.h b/src/core/transport/chttp2/timeout_encoding.h
index 2bef8ba..e6664c6 100644
--- a/src/core/transport/chttp2/timeout_encoding.h
+++ b/src/core/transport/chttp2/timeout_encoding.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_TIMEOUT_ENCODING_H_
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_TIMEOUT_ENCODING_H_
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_TIMEOUT_ENCODING_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_TIMEOUT_ENCODING_H
 
 #include "src/core/support/string.h"
 #include <grpc/support/time.h>
@@ -44,4 +44,4 @@
 void grpc_chttp2_encode_timeout(gpr_timespec timeout, char *buffer);
 int grpc_chttp2_decode_timeout(const char *buffer, gpr_timespec *timeout);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_TIMEOUT_ENCODING_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_TIMEOUT_ENCODING_H */
diff --git a/src/core/transport/chttp2/varint.h b/src/core/transport/chttp2/varint.h
index 8c353c6..ee04ed7 100644
--- a/src/core/transport/chttp2/varint.h
+++ b/src/core/transport/chttp2/varint.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_VARINT_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_VARINT_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_VARINT_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_VARINT_H
 
 #include <grpc/support/port_platform.h>
 
@@ -71,4 +71,4 @@
     }                                                                       \
   } while (0)
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_VARINT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_VARINT_H */
diff --git a/src/core/transport/chttp2_transport.h b/src/core/transport/chttp2_transport.h
index 6fbc596..c5b65bd 100644
--- a/src/core/transport/chttp2_transport.h
+++ b/src/core/transport/chttp2_transport.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_CHTTP2_TRANSPORT_H__
-#define __GRPC_INTERNAL_TRANSPORT_CHTTP2_TRANSPORT_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_TRANSPORT_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_TRANSPORT_H
 
 #include "src/core/iomgr/endpoint.h"
 #include "src/core/transport/transport.h"
@@ -44,4 +44,4 @@
                                   size_t nslices, grpc_mdctx *metadata_context,
                                   int is_client);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_TRANSPORT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_TRANSPORT_H */
diff --git a/src/core/transport/metadata.h b/src/core/transport/metadata.h
index 7a56e34..b8afbeb 100644
--- a/src/core/transport/metadata.h
+++ b/src/core/transport/metadata.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_METADATA_H__
-#define __GRPC_INTERNAL_TRANSPORT_METADATA_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_METADATA_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_METADATA_H
 
 #include <grpc/support/slice.h>
 #include <grpc/support/useful.h>
@@ -137,4 +137,4 @@
 
 #define GRPC_MDSTR_KV_HASH(k_hash, v_hash) (GPR_ROTL((k_hash), 2) ^ (v_hash))
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_METADATA_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_METADATA_H */
diff --git a/src/core/transport/stream_op.h b/src/core/transport/stream_op.h
index 828a7f7..2ffbcce 100644
--- a/src/core/transport/stream_op.h
+++ b/src/core/transport/stream_op.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_STREAM_OP_H__
-#define __GRPC_INTERNAL_TRANSPORT_STREAM_OP_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_STREAM_OP_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_STREAM_OP_H
 
 #include <grpc/grpc.h>
 #include <grpc/support/port_platform.h>
@@ -131,4 +131,4 @@
 void grpc_sopb_append(grpc_stream_op_buffer *sopb, grpc_stream_op *ops,
                       size_t nops);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_STREAM_OP_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_STREAM_OP_H */
diff --git a/src/core/transport/transport.h b/src/core/transport/transport.h
index 60193b1..ce8c17c 100644
--- a/src/core/transport/transport.h
+++ b/src/core/transport/transport.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_TRANSPORT_H__
-#define __GRPC_INTERNAL_TRANSPORT_TRANSPORT_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_TRANSPORT_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_TRANSPORT_H
 
 #include <stddef.h>
 
@@ -254,4 +254,4 @@
    used as a destruction call by setup). */
 void grpc_transport_setup_cancel(grpc_transport_setup *setup);
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_TRANSPORT_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_TRANSPORT_H */
diff --git a/src/core/transport/transport_impl.h b/src/core/transport/transport_impl.h
index d1e0b19..ac275c7 100644
--- a/src/core/transport/transport_impl.h
+++ b/src/core/transport/transport_impl.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_INTERNAL_TRANSPORT_TRANSPORT_IMPL_H__
-#define __GRPC_INTERNAL_TRANSPORT_TRANSPORT_IMPL_H__
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_TRANSPORT_IMPL_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_TRANSPORT_IMPL_H
 
 #include "src/core/transport/transport.h"
 
@@ -84,4 +84,4 @@
   const grpc_transport_vtable *vtable;
 };
 
-#endif /* __GRPC_INTERNAL_TRANSPORT_TRANSPORT_IMPL_H__ */
+#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_TRANSPORT_IMPL_H */
diff --git a/src/core/tsi/fake_transport_security.h b/src/core/tsi/fake_transport_security.h
index 36e62bc..af9730b 100644
--- a/src/core/tsi/fake_transport_security.h
+++ b/src/core/tsi/fake_transport_security.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __FAKE_TRANSPORT_SECURITY_H_
-#define __FAKE_TRANSPORT_SECURITY_H_
+#ifndef GRPC_INTERNAL_CORE_TSI_FAKE_TRANSPORT_SECURITY_H
+#define GRPC_INTERNAL_CORE_TSI_FAKE_TRANSPORT_SECURITY_H
 
 #include "src/core/tsi/transport_security_interface.h"
 
@@ -58,4 +58,4 @@
 }
 #endif
 
-#endif /* __FAKE_TRANSPORT_SECURITY_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TSI_FAKE_TRANSPORT_SECURITY_H */
diff --git a/src/core/tsi/ssl_transport_security.h b/src/core/tsi/ssl_transport_security.h
index eecf2d7..192f7ac 100644
--- a/src/core/tsi/ssl_transport_security.h
+++ b/src/core/tsi/ssl_transport_security.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __SSL_TRANSPORT_SECURITY_H_
-#define __SSL_TRANSPORT_SECURITY_H_
+#ifndef GRPC_INTERNAL_CORE_TSI_SSL_TRANSPORT_SECURITY_H
+#define GRPC_INTERNAL_CORE_TSI_SSL_TRANSPORT_SECURITY_H
 
 #include "src/core/tsi/transport_security_interface.h"
 
@@ -170,4 +170,4 @@
 }
 #endif
 
-#endif /* __SSL_TRANSPORT_SECURITY_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TSI_SSL_TRANSPORT_SECURITY_H */
diff --git a/src/core/tsi/transport_security.h b/src/core/tsi/transport_security.h
index 432da07..e47e258 100644
--- a/src/core/tsi/transport_security.h
+++ b/src/core/tsi/transport_security.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __TRANSPORT_SECURITY_H_
-#define __TRANSPORT_SECURITY_H_
+#ifndef GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_H
+#define GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_H
 
 #include "src/core/tsi/transport_security_interface.h"
 
@@ -115,4 +115,4 @@
 }
 #endif
 
-#endif /* __TRANSPORT_SECURITY_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_H */
diff --git a/src/core/tsi/transport_security_interface.h b/src/core/tsi/transport_security_interface.h
index 90e119c..50de7b9 100644
--- a/src/core/tsi/transport_security_interface.h
+++ b/src/core/tsi/transport_security_interface.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __TRANSPORT_SECURITY_INTERFACE_H_
-#define __TRANSPORT_SECURITY_INTERFACE_H_
+#ifndef GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_INTERFACE_H
+#define GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_INTERFACE_H
 
 #include <stdint.h>
 #include <stdlib.h>
@@ -361,4 +361,4 @@
 }
 #endif
 
-#endif /* __TRANSPORT_SECURITY_INTERFACE_H_ */
+#endif  /* GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_INTERFACE_H */
diff --git a/src/cpp/client/channel.h b/src/cpp/client/channel.h
index e3edcf7..63c6e2b 100644
--- a/src/cpp/client/channel.h
+++ b/src/cpp/client/channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_INTERNAL_CLIENT_CHANNEL_H__
-#define __GRPCPP_INTERNAL_CLIENT_CHANNEL_H__
+#ifndef GRPC_INTERNAL_CPP_CLIENT_CHANNEL_H
+#define GRPC_INTERNAL_CPP_CLIENT_CHANNEL_H
 
 #include <memory>
 
@@ -68,4 +68,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_INTERNAL_CLIENT_CHANNEL_H__
+#endif  // GRPC_INTERNAL_CPP_CLIENT_CHANNEL_H
diff --git a/src/cpp/proto/proto_utils.h b/src/cpp/proto/proto_utils.h
index 834884d..a0af4d6 100644
--- a/src/cpp/proto/proto_utils.h
+++ b/src/cpp/proto/proto_utils.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_INTERNAL_PROTO_PROTO_UTILS_H__
-#define __GRPCPP_INTERNAL_PROTO_PROTO_UTILS_H__
+#ifndef GRPC_INTERNAL_CPP_PROTO_PROTO_UTILS_H
+#define GRPC_INTERNAL_CPP_PROTO_PROTO_UTILS_H
 
 struct grpc_byte_buffer;
 namespace google {
@@ -54,4 +54,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_INTERNAL_PROTO_PROTO_UTILS_H__
+#endif  // GRPC_INTERNAL_CPP_PROTO_PROTO_UTILS_H
diff --git a/src/cpp/server/thread_pool.h b/src/cpp/server/thread_pool.h
index 9c1df0b..6157e40 100644
--- a/src/cpp/server/thread_pool.h
+++ b/src/cpp/server/thread_pool.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_INTERNAL_SERVER_THREAD_POOL_H__
-#define __GRPCPP_INTERNAL_SERVER_THREAD_POOL_H__
+#ifndef GRPC_INTERNAL_CPP_SERVER_THREAD_POOL_H
+#define GRPC_INTERNAL_CPP_SERVER_THREAD_POOL_H
 
 #include <grpc++/config.h>
 #include <grpc++/thread_pool_interface.h>
@@ -62,4 +62,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_INTERNAL_SERVER_THREAD_POOL_H__
+#endif  // GRPC_INTERNAL_CPP_SERVER_THREAD_POOL_H
diff --git a/src/cpp/util/time.h b/src/cpp/util/time.h
index 9f9e582..1994848 100644
--- a/src/cpp/util/time.h
+++ b/src/cpp/util/time.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_INTERNAL_UTIL_TIME_H__
-#define __GRPCPP_INTERNAL_UTIL_TIME_H__
+#ifndef GRPC_INTERNAL_CPP_UTIL_TIME_H
+#define GRPC_INTERNAL_CPP_UTIL_TIME_H
 
 #include <chrono>
 
@@ -48,4 +48,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_INTERNAL_UTIL_TIME_H__
+#endif  // GRPC_INTERNAL_CPP_UTIL_TIME_H
diff --git a/test/core/end2end/cq_verifier.h b/test/core/end2end/cq_verifier.h
index 8f14710..c1e25d8 100644
--- a/test/core/end2end/cq_verifier.h
+++ b/test/core/end2end/cq_verifier.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_END2END_CQ_VERIFIER_H__
-#define __GRPC_TEST_END2END_CQ_VERIFIER_H__
+#ifndef GRPC_TEST_CORE_END2END_CQ_VERIFIER_H
+#define GRPC_TEST_CORE_END2END_CQ_VERIFIER_H
 
 #include <grpc/grpc.h>
 #include "test/core/util/test_config.h"
@@ -76,4 +76,4 @@
 int byte_buffer_eq_string(grpc_byte_buffer *byte_buffer, const char *string);
 int contains_metadata(grpc_metadata_array *array, const char *key, const char *value);
 
-#endif /* __GRPC_TEST_END2END_CQ_VERIFIER_H__ */
+#endif  /* GRPC_TEST_CORE_END2END_CQ_VERIFIER_H */
diff --git a/test/core/end2end/data/ssl_test_data.h b/test/core/end2end/data/ssl_test_data.h
index 4124867..4f4b30e 100644
--- a/test/core/end2end/data/ssl_test_data.h
+++ b/test/core/end2end/data/ssl_test_data.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_TEST_END2END_DATA_SSL_TEST_DATA_H__
-#define __GRPC_TEST_END2END_DATA_SSL_TEST_DATA_H__
+#ifndef GRPC_TEST_CORE_END2END_DATA_SSL_TEST_DATA_H
+#define GRPC_TEST_CORE_END2END_DATA_SSL_TEST_DATA_H
 
 extern const char test_root_cert[];
 extern const char test_server1_cert[];
 extern const char test_server1_key[];
 
-#endif /* __GRPC_TEST_END2END_DATA_SSL_TEST_DATA_H__ */
+#endif  /* GRPC_TEST_CORE_END2END_DATA_SSL_TEST_DATA_H */
diff --git a/test/core/end2end/end2end_tests.h b/test/core/end2end/end2end_tests.h
index 8f2cd0f..b6d9325 100644
--- a/test/core/end2end/end2end_tests.h
+++ b/test/core/end2end/end2end_tests.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_END2END_END2END_TESTS_H__
-#define __GRPC_TEST_END2END_END2END_TESTS_H__
+#ifndef GRPC_TEST_CORE_END2END_END2END_TESTS_H
+#define GRPC_TEST_CORE_END2END_END2END_TESTS_H
 
 #include <grpc/grpc.h>
 
@@ -63,4 +63,4 @@
 
 void grpc_end2end_tests(grpc_end2end_test_config config);
 
-#endif /* __GRPC_TEST_END2END_END2END_TESTS_H__ */
+#endif  /* GRPC_TEST_CORE_END2END_END2END_TESTS_H */
diff --git a/test/core/end2end/tests/cancel_test_helpers.h b/test/core/end2end/tests/cancel_test_helpers.h
index 3dd7437..f2581dc 100644
--- a/test/core/end2end/tests/cancel_test_helpers.h
+++ b/test/core/end2end/tests/cancel_test_helpers.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_END2END_TESTS_CANCEL_TEST_HELPERS_H__
-#define __GRPC_TEST_END2END_TESTS_CANCEL_TEST_HELPERS_H__
+#ifndef GRPC_TEST_CORE_END2END_TESTS_CANCEL_TEST_HELPERS_H
+#define GRPC_TEST_CORE_END2END_TESTS_CANCEL_TEST_HELPERS_H
 
 typedef struct {
   grpc_call_error (*initiate_cancel)(grpc_call *call);
@@ -48,4 +48,4 @@
     {grpc_call_cancel, GRPC_STATUS_CANCELLED, ""},
     {wait_for_deadline, GRPC_STATUS_DEADLINE_EXCEEDED, "Deadline Exceeded"}, };
 
-#endif
+#endif  /* GRPC_TEST_CORE_END2END_TESTS_CANCEL_TEST_HELPERS_H */
diff --git a/test/core/iomgr/endpoint_tests.h b/test/core/iomgr/endpoint_tests.h
index 3be377c..1679d7b 100644
--- a/test/core/iomgr/endpoint_tests.h
+++ b/test/core/iomgr/endpoint_tests.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_IOMGR_ENDPOINT_TESTS_H__
-#define __GRPC_TEST_IOMGR_ENDPOINT_TESTS_H__
+#ifndef GRPC_TEST_CORE_IOMGR_ENDPOINT_TESTS_H
+#define GRPC_TEST_CORE_IOMGR_ENDPOINT_TESTS_H
 
 #include <sys/types.h>
 
@@ -54,4 +54,4 @@
 
 void grpc_endpoint_tests(grpc_endpoint_test_config config);
 
-#endif /* __GRPC_TEST_IOMGR_ENDPOINT_TESTS_H__ */
+#endif  /* GRPC_TEST_CORE_IOMGR_ENDPOINT_TESTS_H */
diff --git a/test/core/statistics/census_log_tests.h b/test/core/statistics/census_log_tests.h
index f829ab3..28bde08 100644
--- a/test/core/statistics/census_log_tests.h
+++ b/test/core/statistics/census_log_tests.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_STATISTICS_LOG_TESTS_H__
-#define __GRPC_TEST_STATISTICS_LOG_TESTS_H__
+#ifndef GRPC_TEST_CORE_STATISTICS_CENSUS_LOG_TESTS_H
+#define GRPC_TEST_CORE_STATISTICS_CENSUS_LOG_TESTS_H
 
 void test_invalid_record_size();
 void test_end_write_with_different_size();
@@ -48,4 +48,4 @@
 void test_performance();
 void test_small_log();
 
-#endif /* __GRPC_TEST_STATISTICS_LOG_TESTS_H__ */
+#endif  /* GRPC_TEST_CORE_STATISTICS_CENSUS_LOG_TESTS_H */
diff --git a/test/core/transport/transport_end2end_tests.h b/test/core/transport/transport_end2end_tests.h
index 3dc2b9b..1edffe9 100644
--- a/test/core/transport/transport_end2end_tests.h
+++ b/test/core/transport/transport_end2end_tests.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_TRANSPORT_TRANSPORT_END2END_TESTS_H__
-#define __GRPC_TEST_TRANSPORT_TRANSPORT_END2END_TESTS_H__
+#ifndef GRPC_TEST_CORE_TRANSPORT_TRANSPORT_END2END_TESTS_H
+#define GRPC_TEST_CORE_TRANSPORT_TRANSPORT_END2END_TESTS_H
 
 #include "src/core/transport/transport.h"
 
@@ -65,4 +65,4 @@
 /* Run the test suite on one configuration */
 void grpc_transport_end2end_tests(grpc_transport_test_config *config);
 
-#endif /* __GRPC_TEST_TRANSPORT_TRANSPORT_END2END_TESTS_H__ */
+#endif  /* GRPC_TEST_CORE_TRANSPORT_TRANSPORT_END2END_TESTS_H */
diff --git a/test/core/util/grpc_profiler.h b/test/core/util/grpc_profiler.h
index a31fcc1..347a1d3 100644
--- a/test/core/util/grpc_profiler.h
+++ b/test/core/util/grpc_profiler.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_UTIL_GRPC_PROFILER_H__
-#define __GRPC_TEST_UTIL_GRPC_PROFILER_H__
+#ifndef GRPC_TEST_CORE_UTIL_GRPC_PROFILER_H
+#define GRPC_TEST_CORE_UTIL_GRPC_PROFILER_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -45,4 +45,4 @@
 }
 #endif /*  __cplusplus */
 
-#endif /* __GRPC_TEST_UTIL_GRPC_PROFILER_H__ */
+#endif  /* GRPC_TEST_CORE_UTIL_GRPC_PROFILER_H */
diff --git a/test/core/util/parse_hexstring.h b/test/core/util/parse_hexstring.h
index 3fce0c9..22bbd17 100644
--- a/test/core/util/parse_hexstring.h
+++ b/test/core/util/parse_hexstring.h
@@ -31,11 +31,11 @@
  *
  */
 
-#ifndef __GRPC_TEST_UTIL_PARSE_HEXSTRING_H_
-#define __GRPC_TEST_UTIL_PARSE_HEXSTRING_H_
+#ifndef GRPC_TEST_CORE_UTIL_PARSE_HEXSTRING_H
+#define GRPC_TEST_CORE_UTIL_PARSE_HEXSTRING_H
 
 #include <grpc/support/slice.h>
 
 gpr_slice parse_hexstring(const char *hexstring);
 
-#endif /* __GRPC_TEST_UTIL_PARSE_HEXSTRING_H_ */
+#endif  /* GRPC_TEST_CORE_UTIL_PARSE_HEXSTRING_H */
diff --git a/test/core/util/port.h b/test/core/util/port.h
index 2a12ab9..b516ec5 100644
--- a/test/core/util/port.h
+++ b/test/core/util/port.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_UTIL_PORT_H__
-#define __GRPC_TEST_UTIL_PORT_H__
+#ifndef GRPC_TEST_CORE_UTIL_PORT_H
+#define GRPC_TEST_CORE_UTIL_PORT_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -49,4 +49,4 @@
 }
 #endif
 
-#endif /* __GRPC_TEST_UTIL_PORT_H__ */
+#endif  /* GRPC_TEST_CORE_UTIL_PORT_H */
diff --git a/test/core/util/slice_splitter.h b/test/core/util/slice_splitter.h
index b67fe73..1ce1c09 100644
--- a/test/core/util/slice_splitter.h
+++ b/test/core/util/slice_splitter.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_UTIL_SLICE_SPLITTER_H__
-#define __GRPC_TEST_UTIL_SLICE_SPLITTER_H__
+#ifndef GRPC_TEST_CORE_UTIL_SLICE_SPLITTER_H
+#define GRPC_TEST_CORE_UTIL_SLICE_SPLITTER_H
 
 /* utility function to split/merge slices together to help create test
    cases */
@@ -65,4 +65,4 @@
 
 const char *grpc_slice_split_mode_name(grpc_slice_split_mode mode);
 
-#endif /* __GRPC_TEST_UTIL_SLICE_SPLITTER_H__ */
+#endif  /* GRPC_TEST_CORE_UTIL_SLICE_SPLITTER_H */
diff --git a/test/core/util/test_config.h b/test/core/util/test_config.h
index 5292c7b..668a069 100644
--- a/test/core/util/test_config.h
+++ b/test/core/util/test_config.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPC_TEST_UTIL_TEST_CONFIG_H__
-#define __GRPC_TEST_UTIL_TEST_CONFIG_H__
+#ifndef GRPC_TEST_CORE_UTIL_TEST_CONFIG_H
+#define GRPC_TEST_CORE_UTIL_TEST_CONFIG_H
 
 #include <grpc/support/time.h>
 
@@ -65,4 +65,4 @@
 }
 #endif /*  __cplusplus */
 
-#endif /* __GRPC_TEST_UTIL_TEST_CONFIG_H__ */
+#endif  /* GRPC_TEST_CORE_UTIL_TEST_CONFIG_H */
diff --git a/test/cpp/util/create_test_channel.h b/test/cpp/util/create_test_channel.h
index 3476b83..5c298ce 100644
--- a/test/cpp/util/create_test_channel.h
+++ b/test/cpp/util/create_test_channel.h
@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef __GRPCPP_TEST_UTIL_CREATE_TEST_CHANNEL_H_
-#define __GRPCPP_TEST_UTIL_CREATE_TEST_CHANNEL_H_
+#ifndef GRPC_TEST_CPP_UTIL_CREATE_TEST_CHANNEL_H
+#define GRPC_TEST_CPP_UTIL_CREATE_TEST_CHANNEL_H
 
 #include <memory>
 
@@ -56,4 +56,4 @@
 
 }  // namespace grpc
 
-#endif  // __GRPCPP_TEST_UTIL_CREATE_TEST_CHANNEL_H_
+#endif  // GRPC_TEST_CPP_UTIL_CREATE_TEST_CHANNEL_H
diff --git a/tools/distrib/guard_headers.sh b/tools/distrib/guard_headers.sh
new file mode 100755
index 0000000..2a54cf8
--- /dev/null
+++ b/tools/distrib/guard_headers.sh
@@ -0,0 +1,90 @@
+#!/bin/bash
+# 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.
+
+
+set -e
+
+cd `dirname $0`/../..
+
+function process_dir {
+  base_dir=$1
+  prefix=$2
+  comment_language=$3
+  (
+    cd $base_dir
+    find . -name "*.h" | while read f ; do
+      guard=${prefix}_`echo ${f#*/} | tr '[:lower:]/.-' '[:upper:]___'`
+      if [ "$comment_language" = "c++" ] ; then
+        comment="// $guard"
+      else
+        comment="/* $guard */"
+      fi
+      awk '
+        BEGIN {
+          guard = "'${guard}'";
+          comment_language = "'${comment_language}'";
+        }
+        prev ~ /^#ifndef/ && !got_first_ifndef {
+          got_first_ifndef = 1;
+          prev = "#ifndef " guard;
+        }
+        prev ~ /^#define/ && !got_first_define {
+          got_first_define = 1;
+          prev = "#define " guard;
+        }
+        NR > 1 { print prev; }
+        { prev = $0; }
+        END {
+          if (prev ~ /^#endif/) {
+            if (comment_language ~ /^c$/) {
+              print "#endif  /* " guard " */";
+            } else if (comment_language ~ /^c\+\+$/) {
+              print "#endif  // " guard;
+            } else {
+              print "ERROR: unknown comment language: " comment_language;
+            }
+          } else {
+            print "ERROR: file does not end with #endif";
+          }
+        }
+      ' "${f}" > "${f}.rewritten"
+      mv "${f}.rewritten" "${f}"
+    done
+  )
+}
+
+process_dir include/grpc GRPC c
+process_dir include/grpc++ GRPCXX c++
+process_dir src/core GRPC_INTERNAL_CORE c
+process_dir src/cpp GRPC_INTERNAL_CPP c++
+process_dir src/compiler GRPC_INTERNAL_COMPILER c++
+process_dir test/core GRPC_TEST_CORE c
+process_dir test/cpp GRPC_TEST_CPP c++
+process_dir examples GRPC_EXAMPLES c++