| // |
| // Copyright 2017 gRPC authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| |
| #include "src/core/ext/filters/workarounds/workaround_cronet_compression_filter.h" |
| |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| |
| #include "src/core/ext/filters/workarounds/workaround_utils.h" |
| #include "src/core/lib/channel/channel_stack_builder.h" |
| #include "src/core/lib/surface/channel_init.h" |
| #include "src/core/lib/transport/metadata.h" |
| |
| typedef struct call_data { |
| // Receive closures are chained: we inject this closure as the |
| // recv_initial_metadata_ready up-call on transport_stream_op, and remember to |
| // call our next_recv_initial_metadata_ready member after handling it. |
| grpc_closure recv_initial_metadata_ready; |
| // Used by recv_initial_metadata_ready. |
| grpc_metadata_batch* recv_initial_metadata; |
| // Original recv_initial_metadata_ready callback, invoked after our own. |
| grpc_closure* next_recv_initial_metadata_ready; |
| |
| // Marks whether the workaround is active |
| bool workaround_active; |
| } call_data; |
| |
| // Find the user agent metadata element in the batch |
| static bool get_user_agent_mdelem(const grpc_metadata_batch* batch, |
| grpc_mdelem* md) { |
| if (batch->idx.named.user_agent != NULL) { |
| *md = batch->idx.named.user_agent->md; |
| return true; |
| } |
| return false; |
| } |
| |
| // Callback invoked when we receive an initial metadata. |
| static void recv_initial_metadata_ready(grpc_exec_ctx* exec_ctx, |
| void* user_data, grpc_error* error) { |
| grpc_call_element* elem = (grpc_call_element*)user_data; |
| call_data* calld = (call_data*)elem->call_data; |
| |
| if (GRPC_ERROR_NONE == error) { |
| grpc_mdelem md; |
| if (get_user_agent_mdelem(calld->recv_initial_metadata, &md)) { |
| grpc_workaround_user_agent_md* user_agent_md = grpc_parse_user_agent(md); |
| if (user_agent_md |
| ->workaround_active[GRPC_WORKAROUND_ID_CRONET_COMPRESSION]) { |
| calld->workaround_active = true; |
| } |
| } |
| } |
| |
| // Invoke the next callback. |
| GRPC_CLOSURE_RUN(exec_ctx, calld->next_recv_initial_metadata_ready, |
| GRPC_ERROR_REF(error)); |
| } |
| |
| // Start transport stream op. |
| static void start_transport_stream_op_batch( |
| grpc_exec_ctx* exec_ctx, grpc_call_element* elem, |
| grpc_transport_stream_op_batch* op) { |
| call_data* calld = (call_data*)elem->call_data; |
| |
| // Inject callback for receiving initial metadata |
| if (op->recv_initial_metadata) { |
| calld->next_recv_initial_metadata_ready = |
| op->payload->recv_initial_metadata.recv_initial_metadata_ready; |
| op->payload->recv_initial_metadata.recv_initial_metadata_ready = |
| &calld->recv_initial_metadata_ready; |
| calld->recv_initial_metadata = |
| op->payload->recv_initial_metadata.recv_initial_metadata; |
| } |
| |
| if (op->send_message) { |
| /* Send message happens after client's user-agent (initial metadata) is |
| * received, so workaround_active must be set already */ |
| if (calld->workaround_active) { |
| op->payload->send_message.send_message->flags |= GRPC_WRITE_NO_COMPRESS; |
| } |
| } |
| |
| // Chain to the next filter. |
| grpc_call_next_op(exec_ctx, elem, op); |
| } |
| |
| // Constructor for call_data. |
| static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx, |
| grpc_call_element* elem, |
| const grpc_call_element_args* args) { |
| call_data* calld = (call_data*)elem->call_data; |
| calld->next_recv_initial_metadata_ready = NULL; |
| calld->workaround_active = false; |
| GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready, |
| recv_initial_metadata_ready, elem, |
| grpc_schedule_on_exec_ctx); |
| return GRPC_ERROR_NONE; |
| } |
| |
| // Destructor for call_data. |
| static void destroy_call_elem(grpc_exec_ctx* exec_ctx, grpc_call_element* elem, |
| const grpc_call_final_info* final_info, |
| grpc_closure* ignored) {} |
| |
| // Constructor for channel_data. |
| static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx, |
| grpc_channel_element* elem, |
| grpc_channel_element_args* args) { |
| return GRPC_ERROR_NONE; |
| } |
| |
| // Destructor for channel_data. |
| static void destroy_channel_elem(grpc_exec_ctx* exec_ctx, |
| grpc_channel_element* elem) {} |
| |
| // Parse the user agent |
| static bool parse_user_agent(grpc_mdelem md) { |
| const char grpc_objc_specifier[] = "grpc-objc/"; |
| const size_t grpc_objc_specifier_len = sizeof(grpc_objc_specifier) - 1; |
| const char cronet_specifier[] = "cronet_http"; |
| const size_t cronet_specifier_len = sizeof(cronet_specifier) - 1; |
| |
| char* user_agent_str = grpc_slice_to_c_string(GRPC_MDVALUE(md)); |
| bool grpc_objc_specifier_seen = false; |
| bool cronet_specifier_seen = false; |
| char *major_version_str = user_agent_str, *minor_version_str; |
| long major_version, minor_version; |
| |
| char* head = strtok(user_agent_str, " "); |
| while (head != NULL) { |
| if (!grpc_objc_specifier_seen && |
| 0 == strncmp(head, grpc_objc_specifier, grpc_objc_specifier_len)) { |
| major_version_str = head + grpc_objc_specifier_len; |
| grpc_objc_specifier_seen = true; |
| } else if (grpc_objc_specifier_seen && |
| 0 == strncmp(head, cronet_specifier, cronet_specifier_len)) { |
| cronet_specifier_seen = true; |
| break; |
| } |
| |
| head = strtok(NULL, " "); |
| } |
| if (grpc_objc_specifier_seen) { |
| major_version_str = strtok(major_version_str, "."); |
| minor_version_str = strtok(NULL, "."); |
| major_version = atol(major_version_str); |
| minor_version = atol(minor_version_str); |
| } |
| |
| gpr_free(user_agent_str); |
| return (grpc_objc_specifier_seen && cronet_specifier_seen && |
| (major_version < 1 || (major_version == 1 && minor_version <= 3))); |
| } |
| |
| const grpc_channel_filter grpc_workaround_cronet_compression_filter = { |
| start_transport_stream_op_batch, |
| grpc_channel_next_op, |
| sizeof(call_data), |
| init_call_elem, |
| grpc_call_stack_ignore_set_pollset_or_pollset_set, |
| destroy_call_elem, |
| 0, |
| init_channel_elem, |
| destroy_channel_elem, |
| grpc_channel_next_get_info, |
| "workaround_cronet_compression"}; |
| |
| static bool register_workaround_cronet_compression( |
| grpc_exec_ctx* exec_ctx, grpc_channel_stack_builder* builder, void* arg) { |
| const grpc_channel_args* channel_args = |
| grpc_channel_stack_builder_get_channel_arguments(builder); |
| const grpc_arg* a = grpc_channel_args_find( |
| channel_args, GRPC_ARG_WORKAROUND_CRONET_COMPRESSION); |
| if (a == NULL) { |
| return true; |
| } |
| if (grpc_channel_arg_get_bool(a, false) == false) { |
| return true; |
| } |
| return grpc_channel_stack_builder_prepend_filter( |
| builder, &grpc_workaround_cronet_compression_filter, NULL, NULL); |
| } |
| |
| void grpc_workaround_cronet_compression_filter_init(void) { |
| grpc_channel_init_register_stage( |
| GRPC_SERVER_CHANNEL, GRPC_WORKAROUND_PRIORITY_HIGH, |
| register_workaround_cronet_compression, NULL); |
| grpc_register_workaround(GRPC_WORKAROUND_ID_CRONET_COMPRESSION, |
| parse_user_agent); |
| } |
| |
| void grpc_workaround_cronet_compression_filter_shutdown(void) {} |