1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 #include <grpc/support/port_platform.h>
20
21 #include <grpc/grpc.h>
22
23 #include <string.h>
24
25 #include <grpc/support/alloc.h>
26 #include <grpc/support/log.h>
27
28 #include "src/core/lib/gprpp/atomic.h"
29
30 #include "src/core/lib/channel/channel_stack.h"
31 #include "src/core/lib/gpr/string.h"
32 #include "src/core/lib/surface/api_trace.h"
33 #include "src/core/lib/surface/call.h"
34 #include "src/core/lib/surface/channel.h"
35 #include "src/core/lib/surface/lame_client.h"
36 #include "src/core/lib/transport/static_metadata.h"
37
38 namespace grpc_core {
39
40 namespace {
41
42 struct CallData {
43 grpc_call_combiner* call_combiner;
44 grpc_linked_mdelem status;
45 grpc_linked_mdelem details;
46 grpc_core::atomic<bool> filled_metadata;
47 };
48
49 struct ChannelData {
50 grpc_status_code error_code;
51 const char* error_message;
52 };
53
fill_metadata(grpc_call_element * elem,grpc_metadata_batch * mdb)54 static void fill_metadata(grpc_call_element* elem, grpc_metadata_batch* mdb) {
55 CallData* calld = static_cast<CallData*>(elem->call_data);
56 bool expected = false;
57 if (!calld->filled_metadata.compare_exchange_strong(
58 expected, true, grpc_core::memory_order_relaxed,
59 grpc_core::memory_order_relaxed)) {
60 return;
61 }
62 ChannelData* chand = static_cast<ChannelData*>(elem->channel_data);
63 char tmp[GPR_LTOA_MIN_BUFSIZE];
64 gpr_ltoa(chand->error_code, tmp);
65 calld->status.md = grpc_mdelem_from_slices(
66 GRPC_MDSTR_GRPC_STATUS, grpc_slice_from_copied_string(tmp));
67 calld->details.md = grpc_mdelem_from_slices(
68 GRPC_MDSTR_GRPC_MESSAGE,
69 grpc_slice_from_copied_string(chand->error_message));
70 calld->status.prev = calld->details.next = nullptr;
71 calld->status.next = &calld->details;
72 calld->details.prev = &calld->status;
73 mdb->list.head = &calld->status;
74 mdb->list.tail = &calld->details;
75 mdb->list.count = 2;
76 mdb->deadline = GRPC_MILLIS_INF_FUTURE;
77 }
78
lame_start_transport_stream_op_batch(grpc_call_element * elem,grpc_transport_stream_op_batch * op)79 static void lame_start_transport_stream_op_batch(
80 grpc_call_element* elem, grpc_transport_stream_op_batch* op) {
81 CallData* calld = static_cast<CallData*>(elem->call_data);
82 if (op->recv_initial_metadata) {
83 fill_metadata(elem,
84 op->payload->recv_initial_metadata.recv_initial_metadata);
85 } else if (op->recv_trailing_metadata) {
86 fill_metadata(elem,
87 op->payload->recv_trailing_metadata.recv_trailing_metadata);
88 }
89 grpc_transport_stream_op_batch_finish_with_failure(
90 op, GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"),
91 calld->call_combiner);
92 }
93
lame_get_channel_info(grpc_channel_element * elem,const grpc_channel_info * channel_info)94 static void lame_get_channel_info(grpc_channel_element* elem,
95 const grpc_channel_info* channel_info) {}
96
lame_start_transport_op(grpc_channel_element * elem,grpc_transport_op * op)97 static void lame_start_transport_op(grpc_channel_element* elem,
98 grpc_transport_op* op) {
99 if (op->on_connectivity_state_change) {
100 GPR_ASSERT(*op->connectivity_state != GRPC_CHANNEL_SHUTDOWN);
101 *op->connectivity_state = GRPC_CHANNEL_SHUTDOWN;
102 GRPC_CLOSURE_SCHED(op->on_connectivity_state_change, GRPC_ERROR_NONE);
103 }
104 if (op->send_ping.on_initiate != nullptr) {
105 GRPC_CLOSURE_SCHED(
106 op->send_ping.on_initiate,
107 GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"));
108 }
109 if (op->send_ping.on_ack != nullptr) {
110 GRPC_CLOSURE_SCHED(
111 op->send_ping.on_ack,
112 GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"));
113 }
114 GRPC_ERROR_UNREF(op->disconnect_with_error);
115 if (op->on_consumed != nullptr) {
116 GRPC_CLOSURE_SCHED(op->on_consumed, GRPC_ERROR_NONE);
117 }
118 }
119
init_call_elem(grpc_call_element * elem,const grpc_call_element_args * args)120 static grpc_error* init_call_elem(grpc_call_element* elem,
121 const grpc_call_element_args* args) {
122 CallData* calld = static_cast<CallData*>(elem->call_data);
123 calld->call_combiner = args->call_combiner;
124 return GRPC_ERROR_NONE;
125 }
126
destroy_call_elem(grpc_call_element * elem,const grpc_call_final_info * final_info,grpc_closure * then_schedule_closure)127 static void destroy_call_elem(grpc_call_element* elem,
128 const grpc_call_final_info* final_info,
129 grpc_closure* then_schedule_closure) {
130 GRPC_CLOSURE_SCHED(then_schedule_closure, GRPC_ERROR_NONE);
131 }
132
init_channel_elem(grpc_channel_element * elem,grpc_channel_element_args * args)133 static grpc_error* init_channel_elem(grpc_channel_element* elem,
134 grpc_channel_element_args* args) {
135 GPR_ASSERT(args->is_first);
136 GPR_ASSERT(args->is_last);
137 return GRPC_ERROR_NONE;
138 }
139
destroy_channel_elem(grpc_channel_element * elem)140 static void destroy_channel_elem(grpc_channel_element* elem) {}
141
142 } // namespace
143
144 } // namespace grpc_core
145
146 const grpc_channel_filter grpc_lame_filter = {
147 grpc_core::lame_start_transport_stream_op_batch,
148 grpc_core::lame_start_transport_op,
149 sizeof(grpc_core::CallData),
150 grpc_core::init_call_elem,
151 grpc_call_stack_ignore_set_pollset_or_pollset_set,
152 grpc_core::destroy_call_elem,
153 sizeof(grpc_core::ChannelData),
154 grpc_core::init_channel_elem,
155 grpc_core::destroy_channel_elem,
156 grpc_core::lame_get_channel_info,
157 "lame-client",
158 };
159
160 #define CHANNEL_STACK_FROM_CHANNEL(c) ((grpc_channel_stack*)((c) + 1))
161
grpc_lame_client_channel_create(const char * target,grpc_status_code error_code,const char * error_message)162 grpc_channel* grpc_lame_client_channel_create(const char* target,
163 grpc_status_code error_code,
164 const char* error_message) {
165 grpc_core::ExecCtx exec_ctx;
166 grpc_channel_element* elem;
167 grpc_channel* channel =
168 grpc_channel_create(target, nullptr, GRPC_CLIENT_LAME_CHANNEL, nullptr);
169 elem = grpc_channel_stack_element(grpc_channel_get_channel_stack(channel), 0);
170 GRPC_API_TRACE(
171 "grpc_lame_client_channel_create(target=%s, error_code=%d, "
172 "error_message=%s)",
173 3, (target, (int)error_code, error_message));
174 GPR_ASSERT(elem->filter == &grpc_lame_filter);
175 auto chand = static_cast<grpc_core::ChannelData*>(elem->channel_data);
176 chand->error_code = error_code;
177 chand->error_message = error_message;
178
179 return channel;
180 }
181