1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
|
/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "src/core/ext/client_config/subchannel.h"
#include <limits.h>
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/avl.h>
#include "src/core/ext/client_config/client_channel.h"
#include "src/core/ext/client_config/initial_connect_string.h"
#include "src/core/ext/client_config/subchannel_index.h"
#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/channel/connected_channel.h"
#include "src/core/lib/iomgr/timer.h"
#include "src/core/lib/profiling/timers.h"
#include "src/core/lib/support/backoff.h"
#include "src/core/lib/surface/channel.h"
#include "src/core/lib/surface/channel_init.h"
#include "src/core/lib/transport/connectivity_state.h"
#define INTERNAL_REF_BITS 16
#define STRONG_REF_MASK (~(gpr_atm)((1 << INTERNAL_REF_BITS) - 1))
#define GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS 20
#define GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS 1
#define GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER 1.6
#define GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS 120
#define GRPC_SUBCHANNEL_RECONNECT_JITTER 0.2
#define GET_CONNECTED_SUBCHANNEL(subchannel, barrier) \
((grpc_connected_subchannel *)(gpr_atm_##barrier##_load( \
&(subchannel)->connected_subchannel)))
typedef struct {
grpc_closure closure;
grpc_subchannel *subchannel;
grpc_connectivity_state connectivity_state;
} state_watcher;
typedef struct external_state_watcher {
grpc_subchannel *subchannel;
grpc_pollset_set *pollset_set;
grpc_closure *notify;
grpc_closure closure;
struct external_state_watcher *next;
struct external_state_watcher *prev;
} external_state_watcher;
struct grpc_subchannel {
grpc_connector *connector;
/** refcount
- lower INTERNAL_REF_BITS bits are for internal references:
these do not keep the subchannel open.
- upper remaining bits are for public references: these do
keep the subchannel open */
gpr_atm ref_pair;
/** non-transport related channel filters */
const grpc_channel_filter **filters;
size_t num_filters;
/** channel arguments */
grpc_channel_args *args;
/** address to connect to */
struct sockaddr *addr;
size_t addr_len;
grpc_subchannel_key *key;
/** initial string to send to peer */
gpr_slice initial_connect_string;
/** set during connection */
grpc_connect_out_args connecting_result;
/** callback for connection finishing */
grpc_closure connected;
/** pollset_set tracking who's interested in a connection
being setup */
grpc_pollset_set *pollset_set;
/** active connection, or null; of type grpc_connected_subchannel */
gpr_atm connected_subchannel;
/** mutex protecting remaining elements */
gpr_mu mu;
/** have we seen a disconnection? */
int disconnected;
/** are we connecting */
int connecting;
/** connectivity state tracking */
grpc_connectivity_state_tracker state_tracker;
external_state_watcher root_external_state_watcher;
/** next connect attempt time */
gpr_timespec next_attempt;
/** backoff state */
gpr_backoff backoff_state;
/** do we have an active alarm? */
int have_alarm;
/** our alarm */
grpc_timer alarm;
};
struct grpc_subchannel_call {
grpc_connected_subchannel *connection;
};
#define SUBCHANNEL_CALL_TO_CALL_STACK(call) ((grpc_call_stack *)((call) + 1))
#define CHANNEL_STACK_FROM_CONNECTION(con) ((grpc_channel_stack *)(con))
#define CALLSTACK_TO_SUBCHANNEL_CALL(callstack) \
(((grpc_subchannel_call *)(callstack)) - 1)
static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *subchannel,
grpc_error *error);
#ifdef GRPC_STREAM_REFCOUNT_DEBUG
#define REF_REASON reason
#define REF_LOG(name, p) \
gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "%s: %p ref %d -> %d %s", \
(name), (p), (p)->refs.count, (p)->refs.count + 1, reason)
#define UNREF_LOG(name, p) \
gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "%s: %p unref %d -> %d %s", \
(name), (p), (p)->refs.count, (p)->refs.count - 1, reason)
#define REF_MUTATE_EXTRA_ARGS \
GRPC_SUBCHANNEL_REF_EXTRA_ARGS, const char *purpose
#define REF_MUTATE_PURPOSE(x) , file, line, reason, x
#else
#define REF_REASON ""
#define REF_LOG(name, p) \
do { \
} while (0)
#define UNREF_LOG(name, p) \
do { \
} while (0)
#define REF_MUTATE_EXTRA_ARGS
#define REF_MUTATE_PURPOSE(x)
#endif
/*
* connection implementation
*/
static void connection_destroy(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
grpc_connected_subchannel *c = arg;
grpc_channel_stack_destroy(exec_ctx, CHANNEL_STACK_FROM_CONNECTION(c));
gpr_free(c);
}
void grpc_connected_subchannel_ref(
grpc_connected_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
GRPC_CHANNEL_STACK_REF(CHANNEL_STACK_FROM_CONNECTION(c), REF_REASON);
}
void grpc_connected_subchannel_unref(grpc_exec_ctx *exec_ctx,
grpc_connected_subchannel *c
GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
GRPC_CHANNEL_STACK_UNREF(exec_ctx, CHANNEL_STACK_FROM_CONNECTION(c),
REF_REASON);
}
/*
* grpc_subchannel implementation
*/
static void subchannel_destroy(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
grpc_subchannel *c = arg;
gpr_free((void *)c->filters);
grpc_channel_args_destroy(c->args);
gpr_free(c->addr);
gpr_slice_unref(c->initial_connect_string);
grpc_connectivity_state_destroy(exec_ctx, &c->state_tracker);
grpc_connector_unref(exec_ctx, c->connector);
grpc_pollset_set_destroy(c->pollset_set);
grpc_subchannel_key_destroy(exec_ctx, c->key);
gpr_free(c);
}
static gpr_atm ref_mutate(grpc_subchannel *c, gpr_atm delta,
int barrier REF_MUTATE_EXTRA_ARGS) {
gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&c->ref_pair, delta)
: gpr_atm_no_barrier_fetch_add(&c->ref_pair, delta);
#ifdef GRPC_STREAM_REFCOUNT_DEBUG
gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
"SUBCHANNEL: %p %s 0x%08" PRIxPTR " -> 0x%08" PRIxPTR " [%s]", c,
purpose, old_val, old_val + delta, reason);
#endif
return old_val;
}
grpc_subchannel *grpc_subchannel_ref(
grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = ref_mutate(c, (1 << INTERNAL_REF_BITS),
0 REF_MUTATE_PURPOSE("STRONG_REF"));
GPR_ASSERT((old_refs & STRONG_REF_MASK) != 0);
return c;
}
grpc_subchannel *grpc_subchannel_weak_ref(
grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = ref_mutate(c, 1, 0 REF_MUTATE_PURPOSE("WEAK_REF"));
GPR_ASSERT(old_refs != 0);
return c;
}
grpc_subchannel *grpc_subchannel_ref_from_weak_ref(
grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
if (!c) return NULL;
for (;;) {
gpr_atm old_refs = gpr_atm_acq_load(&c->ref_pair);
if (old_refs >= (1 << INTERNAL_REF_BITS)) {
gpr_atm new_refs = old_refs + (1 << INTERNAL_REF_BITS);
if (gpr_atm_rel_cas(&c->ref_pair, old_refs, new_refs)) {
return c;
}
} else {
return NULL;
}
}
}
static void disconnect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
grpc_connected_subchannel *con;
grpc_subchannel_index_unregister(exec_ctx, c->key, c);
gpr_mu_lock(&c->mu);
GPR_ASSERT(!c->disconnected);
c->disconnected = 1;
grpc_connector_shutdown(exec_ctx, c->connector);
con = GET_CONNECTED_SUBCHANNEL(c, no_barrier);
if (con != NULL) {
GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, con, "connection");
gpr_atm_no_barrier_store(&c->connected_subchannel, (gpr_atm)0xdeadbeef);
}
gpr_mu_unlock(&c->mu);
}
void grpc_subchannel_unref(grpc_exec_ctx *exec_ctx,
grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = ref_mutate(c, (gpr_atm)1 - (gpr_atm)(1 << INTERNAL_REF_BITS),
1 REF_MUTATE_PURPOSE("STRONG_UNREF"));
if ((old_refs & STRONG_REF_MASK) == (1 << INTERNAL_REF_BITS)) {
disconnect(exec_ctx, c);
}
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "strong-unref");
}
void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
grpc_subchannel *c
GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = ref_mutate(c, -(gpr_atm)1, 1 REF_MUTATE_PURPOSE("WEAK_UNREF"));
if (old_refs == 1) {
grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(subchannel_destroy, c),
GRPC_ERROR_NONE, NULL);
}
}
grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
grpc_connector *connector,
grpc_subchannel_args *args) {
grpc_subchannel_key *key = grpc_subchannel_key_create(connector, args);
grpc_subchannel *c = grpc_subchannel_index_find(exec_ctx, key);
if (c) {
grpc_subchannel_key_destroy(exec_ctx, key);
return c;
}
c = gpr_malloc(sizeof(*c));
memset(c, 0, sizeof(*c));
c->key = key;
gpr_atm_no_barrier_store(&c->ref_pair, 1 << INTERNAL_REF_BITS);
c->connector = connector;
grpc_connector_ref(c->connector);
c->num_filters = args->filter_count;
if (c->num_filters > 0) {
c->filters = gpr_malloc(sizeof(grpc_channel_filter *) * c->num_filters);
memcpy((void *)c->filters, args->filters,
sizeof(grpc_channel_filter *) * c->num_filters);
} else {
c->filters = NULL;
}
c->addr = gpr_malloc(args->addr_len);
if (args->addr_len) memcpy(c->addr, args->addr, args->addr_len);
c->pollset_set = grpc_pollset_set_create();
c->addr_len = args->addr_len;
grpc_set_initial_connect_string(&c->addr, &c->addr_len,
&c->initial_connect_string);
c->args = grpc_channel_args_copy(args->args);
c->root_external_state_watcher.next = c->root_external_state_watcher.prev =
&c->root_external_state_watcher;
grpc_closure_init(&c->connected, subchannel_connected, c);
grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
"subchannel");
int initial_backoff_ms =
GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000;
int max_backoff_ms = GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS * 1000;
bool fixed_reconnect_backoff = false;
if (c->args) {
for (size_t i = 0; i < c->args->num_args; i++) {
if (0 == strcmp(c->args->args[i].key,
"grpc.testing.fixed_reconnect_backoff")) {
GPR_ASSERT(c->args->args[i].type == GRPC_ARG_INTEGER);
fixed_reconnect_backoff = true;
initial_backoff_ms = max_backoff_ms = grpc_channel_arg_get_integer(
&c->args->args[i],
(grpc_integer_options){initial_backoff_ms, 100, INT_MAX});
} else if (0 == strcmp(c->args->args[i].key,
GRPC_ARG_MAX_RECONNECT_BACKOFF_MS)) {
fixed_reconnect_backoff = false;
max_backoff_ms = grpc_channel_arg_get_integer(
&c->args->args[i],
(grpc_integer_options){max_backoff_ms, 100, INT_MAX});
} else if (0 == strcmp(c->args->args[i].key,
GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS)) {
fixed_reconnect_backoff = false;
initial_backoff_ms = grpc_channel_arg_get_integer(
&c->args->args[i],
(grpc_integer_options){initial_backoff_ms, 100, INT_MAX});
}
}
}
gpr_backoff_init(
&c->backoff_state,
fixed_reconnect_backoff ? 1.0
: GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER,
fixed_reconnect_backoff ? 0.0 : GRPC_SUBCHANNEL_RECONNECT_JITTER,
initial_backoff_ms, max_backoff_ms);
gpr_mu_init(&c->mu);
return grpc_subchannel_index_register(exec_ctx, key, c);
}
static void continue_connect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
grpc_connect_in_args args;
args.interested_parties = c->pollset_set;
args.addr = c->addr;
args.addr_len = c->addr_len;
args.deadline = c->next_attempt;
args.channel_args = c->args;
args.initial_connect_string = c->initial_connect_string;
grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE,
"state_change");
grpc_connector_connect(exec_ctx, c->connector, &args, &c->connecting_result,
&c->connected);
}
static void start_connect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
c->next_attempt =
gpr_backoff_begin(&c->backoff_state, gpr_now(GPR_CLOCK_MONOTONIC));
continue_connect(exec_ctx, c);
}
grpc_connectivity_state grpc_subchannel_check_connectivity(grpc_subchannel *c,
grpc_error **error) {
grpc_connectivity_state state;
gpr_mu_lock(&c->mu);
state = grpc_connectivity_state_check(&c->state_tracker, error);
gpr_mu_unlock(&c->mu);
return state;
}
static void on_external_state_watcher_done(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
external_state_watcher *w = arg;
grpc_closure *follow_up = w->notify;
if (w->pollset_set != NULL) {
grpc_pollset_set_del_pollset_set(exec_ctx, w->subchannel->pollset_set,
w->pollset_set);
}
gpr_mu_lock(&w->subchannel->mu);
w->next->prev = w->prev;
w->prev->next = w->next;
gpr_mu_unlock(&w->subchannel->mu);
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, w->subchannel, "external_state_watcher");
gpr_free(w);
follow_up->cb(exec_ctx, follow_up->cb_arg, error);
}
void grpc_subchannel_notify_on_state_change(
grpc_exec_ctx *exec_ctx, grpc_subchannel *c,
grpc_pollset_set *interested_parties, grpc_connectivity_state *state,
grpc_closure *notify) {
external_state_watcher *w;
if (state == NULL) {
gpr_mu_lock(&c->mu);
for (w = c->root_external_state_watcher.next;
w != &c->root_external_state_watcher; w = w->next) {
if (w->notify == notify) {
grpc_connectivity_state_notify_on_state_change(
exec_ctx, &c->state_tracker, NULL, &w->closure);
}
}
gpr_mu_unlock(&c->mu);
} else {
w = gpr_malloc(sizeof(*w));
w->subchannel = c;
w->pollset_set = interested_parties;
w->notify = notify;
grpc_closure_init(&w->closure, on_external_state_watcher_done, w);
if (interested_parties != NULL) {
grpc_pollset_set_add_pollset_set(exec_ctx, c->pollset_set,
interested_parties);
}
GRPC_SUBCHANNEL_WEAK_REF(c, "external_state_watcher");
gpr_mu_lock(&c->mu);
w->next = &c->root_external_state_watcher;
w->prev = w->next->prev;
w->next->prev = w->prev->next = w;
if (grpc_connectivity_state_notify_on_state_change(
exec_ctx, &c->state_tracker, state, &w->closure)) {
c->connecting = 1;
/* released by connection */
GRPC_SUBCHANNEL_WEAK_REF(c, "connecting");
start_connect(exec_ctx, c);
}
gpr_mu_unlock(&c->mu);
}
}
void grpc_connected_subchannel_process_transport_op(
grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
grpc_transport_op *op) {
grpc_channel_stack *channel_stack = CHANNEL_STACK_FROM_CONNECTION(con);
grpc_channel_element *top_elem = grpc_channel_stack_element(channel_stack, 0);
top_elem->filter->start_transport_op(exec_ctx, top_elem, op);
}
static void subchannel_on_child_state_changed(grpc_exec_ctx *exec_ctx, void *p,
grpc_error *error) {
state_watcher *sw = p;
grpc_subchannel *c = sw->subchannel;
gpr_mu *mu = &c->mu;
gpr_mu_lock(mu);
/* if we failed just leave this closure */
if (sw->connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
/* any errors on a subchannel ==> we're done, create a new one */
sw->connectivity_state = GRPC_CHANNEL_SHUTDOWN;
}
grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
sw->connectivity_state, GRPC_ERROR_REF(error),
"reflect_child");
if (sw->connectivity_state != GRPC_CHANNEL_SHUTDOWN) {
grpc_connected_subchannel_notify_on_state_change(
exec_ctx, GET_CONNECTED_SUBCHANNEL(c, no_barrier), NULL,
&sw->connectivity_state, &sw->closure);
GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
sw = NULL;
}
gpr_mu_unlock(mu);
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "state_watcher");
gpr_free(sw);
}
static void connected_subchannel_state_op(grpc_exec_ctx *exec_ctx,
grpc_connected_subchannel *con,
grpc_pollset_set *interested_parties,
grpc_connectivity_state *state,
grpc_closure *closure) {
grpc_transport_op *op = grpc_make_transport_op(NULL);
grpc_channel_element *elem;
op->connectivity_state = state;
op->on_connectivity_state_change = closure;
op->bind_pollset_set = interested_parties;
elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(con), 0);
elem->filter->start_transport_op(exec_ctx, elem, op);
}
void grpc_connected_subchannel_notify_on_state_change(
grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
grpc_pollset_set *interested_parties, grpc_connectivity_state *state,
grpc_closure *closure) {
connected_subchannel_state_op(exec_ctx, con, interested_parties, state,
closure);
}
void grpc_connected_subchannel_ping(grpc_exec_ctx *exec_ctx,
grpc_connected_subchannel *con,
grpc_closure *closure) {
grpc_transport_op *op = grpc_make_transport_op(NULL);
grpc_channel_element *elem;
op->send_ping = closure;
elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(con), 0);
elem->filter->start_transport_op(exec_ctx, elem, op);
}
static void publish_transport_locked(grpc_exec_ctx *exec_ctx,
grpc_subchannel *c) {
grpc_connected_subchannel *con;
grpc_channel_stack *stk;
state_watcher *sw_subchannel;
/* construct channel stack */
grpc_channel_stack_builder *builder = grpc_channel_stack_builder_create();
grpc_channel_stack_builder_set_channel_arguments(
builder, c->connecting_result.channel_args);
grpc_channel_stack_builder_set_transport(builder,
c->connecting_result.transport);
if (grpc_channel_init_create_stack(exec_ctx, builder,
GRPC_CLIENT_SUBCHANNEL)) {
con = grpc_channel_stack_builder_finish(exec_ctx, builder, 0, 1,
connection_destroy, NULL);
} else {
grpc_channel_stack_builder_destroy(builder);
abort(); /* TODO(ctiller): what to do here (previously we just crashed) */
}
stk = CHANNEL_STACK_FROM_CONNECTION(con);
memset(&c->connecting_result, 0, sizeof(c->connecting_result));
/* initialize state watcher */
sw_subchannel = gpr_malloc(sizeof(*sw_subchannel));
sw_subchannel->subchannel = c;
sw_subchannel->connectivity_state = GRPC_CHANNEL_READY;
grpc_closure_init(&sw_subchannel->closure, subchannel_on_child_state_changed,
sw_subchannel);
if (c->disconnected) {
gpr_free(sw_subchannel);
grpc_channel_stack_destroy(exec_ctx, stk);
gpr_free(con);
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
return;
}
/* publish */
/* TODO(ctiller): this full barrier seems to clear up a TSAN failure.
I'd have expected the rel_cas below to be enough, but
seemingly it's not.
Re-evaluate if we really need this. */
gpr_atm_full_barrier();
GPR_ASSERT(gpr_atm_rel_cas(&c->connected_subchannel, 0, (gpr_atm)con));
c->connecting = 0;
/* setup subchannel watching connected subchannel for changes; subchannel
ref
for connecting is donated
to the state watcher */
GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
grpc_connected_subchannel_notify_on_state_change(
exec_ctx, con, c->pollset_set, &sw_subchannel->connectivity_state,
&sw_subchannel->closure);
/* signal completion */
grpc_connectivity_state_set(exec_ctx, &c->state_tracker, GRPC_CHANNEL_READY,
GRPC_ERROR_NONE, "connected");
}
static void on_alarm(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
grpc_subchannel *c = arg;
gpr_mu_lock(&c->mu);
c->have_alarm = 0;
if (c->disconnected) {
error = GRPC_ERROR_CREATE_REFERENCING("Disconnected", &error, 1);
} else {
GRPC_ERROR_REF(error);
}
if (error == GRPC_ERROR_NONE) {
gpr_log(GPR_INFO, "Failed to connect to channel, retrying");
c->next_attempt =
gpr_backoff_step(&c->backoff_state, gpr_now(GPR_CLOCK_MONOTONIC));
continue_connect(exec_ctx, c);
gpr_mu_unlock(&c->mu);
} else {
gpr_mu_unlock(&c->mu);
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
}
GRPC_ERROR_UNREF(error);
}
static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
grpc_error *error) {
grpc_subchannel *c = arg;
grpc_channel_args *delete_channel_args = c->connecting_result.channel_args;
GRPC_SUBCHANNEL_WEAK_REF(c, "connected");
gpr_mu_lock(&c->mu);
if (c->connecting_result.transport != NULL) {
publish_transport_locked(exec_ctx, c);
} else if (c->disconnected) {
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
} else {
gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
GPR_ASSERT(!c->have_alarm);
c->have_alarm = 1;
grpc_connectivity_state_set(
exec_ctx, &c->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
grpc_error_set_int(
GRPC_ERROR_CREATE_REFERENCING("Connect Failed", &error, 1),
GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE),
"connect_failed");
gpr_timespec time_til_next = gpr_time_sub(c->next_attempt, now);
const char *errmsg = grpc_error_string(error);
gpr_log(GPR_INFO, "Connect failed: %s", errmsg);
if (gpr_time_cmp(time_til_next, gpr_time_0(time_til_next.clock_type)) <=
0) {
gpr_log(GPR_INFO, "Retry immediately");
} else {
gpr_log(GPR_INFO, "Retry in %" PRId64 ".%09d seconds",
time_til_next.tv_sec, time_til_next.tv_nsec);
}
grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, on_alarm, c, now);
grpc_error_free_string(errmsg);
}
gpr_mu_unlock(&c->mu);
GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
grpc_channel_args_destroy(delete_channel_args);
}
/*
* grpc_subchannel_call implementation
*/
static void subchannel_call_destroy(grpc_exec_ctx *exec_ctx, void *call,
grpc_error *error) {
grpc_subchannel_call *c = call;
GPR_TIMER_BEGIN("grpc_subchannel_call_unref.destroy", 0);
grpc_connected_subchannel *connection = c->connection;
grpc_call_stack_destroy(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c), NULL, c);
GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, connection, "subchannel_call");
GPR_TIMER_END("grpc_subchannel_call_unref.destroy", 0);
}
void grpc_subchannel_call_ref(
grpc_subchannel_call *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
GRPC_CALL_STACK_REF(SUBCHANNEL_CALL_TO_CALL_STACK(c), REF_REASON);
}
void grpc_subchannel_call_unref(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call *c
GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
GRPC_CALL_STACK_UNREF(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c), REF_REASON);
}
char *grpc_subchannel_call_get_peer(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call *call) {
grpc_call_stack *call_stack = SUBCHANNEL_CALL_TO_CALL_STACK(call);
grpc_call_element *top_elem = grpc_call_stack_element(call_stack, 0);
return top_elem->filter->get_peer(exec_ctx, top_elem);
}
void grpc_subchannel_call_process_op(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call *call,
grpc_transport_stream_op *op) {
GPR_TIMER_BEGIN("grpc_subchannel_call_process_op", 0);
grpc_call_stack *call_stack = SUBCHANNEL_CALL_TO_CALL_STACK(call);
grpc_call_element *top_elem = grpc_call_stack_element(call_stack, 0);
top_elem->filter->start_transport_stream_op(exec_ctx, top_elem, op);
GPR_TIMER_END("grpc_subchannel_call_process_op", 0);
}
grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
grpc_subchannel *c) {
return GET_CONNECTED_SUBCHANNEL(c, acq);
}
grpc_error *grpc_connected_subchannel_create_call(
grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
grpc_polling_entity *pollent, gpr_timespec deadline,
grpc_subchannel_call **call) {
grpc_channel_stack *chanstk = CHANNEL_STACK_FROM_CONNECTION(con);
*call = gpr_malloc(sizeof(grpc_subchannel_call) + chanstk->call_stack_size);
grpc_call_stack *callstk = SUBCHANNEL_CALL_TO_CALL_STACK(*call);
(*call)->connection = con; // Ref is added below.
grpc_error *error =
grpc_call_stack_init(exec_ctx, chanstk, 1, subchannel_call_destroy, *call,
NULL, NULL, deadline, callstk);
if (error != GRPC_ERROR_NONE) {
const char *error_string = grpc_error_string(error);
gpr_log(GPR_ERROR, "error: %s", error_string);
grpc_error_free_string(error_string);
gpr_free(*call);
return error;
}
GRPC_CONNECTED_SUBCHANNEL_REF(con, "subchannel_call");
grpc_call_stack_set_pollset_or_pollset_set(exec_ctx, callstk, pollent);
return GRPC_ERROR_NONE;
}
grpc_call_stack *grpc_subchannel_call_get_call_stack(
grpc_subchannel_call *subchannel_call) {
return SUBCHANNEL_CALL_TO_CALL_STACK(subchannel_call);
}
|