aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/lib/client_config/subchannel.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/core/lib/client_config/subchannel.c')
-rw-r--r--src/core/lib/client_config/subchannel.c678
1 files changed, 678 insertions, 0 deletions
diff --git a/src/core/lib/client_config/subchannel.c b/src/core/lib/client_config/subchannel.c
new file mode 100644
index 0000000000..41242f0dd7
--- /dev/null
+++ b/src/core/lib/client_config/subchannel.c
@@ -0,0 +1,678 @@
+/*
+ *
+ * Copyright 2015-2016, 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/lib/client_config/subchannel.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/avl.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/client_channel.h"
+#include "src/core/lib/channel/connected_channel.h"
+#include "src/core/lib/client_config/initial_connect_string.h"
+#include "src/core/lib/client_config/subchannel_index.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;
+ /** current random value */
+ uint32_t random;
+};
+
+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,
+ bool iomgr_success);
+
+#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,
+ bool success) {
+ 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,
+ bool success) {
+ 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 % 12s 0x%08x -> 0x%08x [%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, 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_enqueue(exec_ctx, grpc_closure_create(subchannel_destroy, c),
+ true, NULL);
+ }
+}
+
+static uint32_t random_seed() {
+ return (uint32_t)(gpr_time_to_millis(gpr_now(GPR_CLOCK_MONOTONIC)));
+}
+
+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);
+ 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->random = random_seed();
+ 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");
+ gpr_backoff_init(&c->backoff_state,
+ GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER,
+ GRPC_SUBCHANNEL_RECONNECT_JITTER,
+ GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000,
+ GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS * 1000);
+ 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);
+ gpr_backoff_init(&c->backoff_state, 1.0, 0.0,
+ c->args->args[i].value.integer,
+ c->args->args[i].value.integer);
+ }
+ }
+ }
+ 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, "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_connectivity_state state;
+ gpr_mu_lock(&c->mu);
+ state = grpc_connectivity_state_check(&c->state_tracker);
+ gpr_mu_unlock(&c->mu);
+ return state;
+}
+
+static void on_external_state_watcher_done(grpc_exec_ctx *exec_ctx, void *arg,
+ bool success) {
+ 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, success);
+}
+
+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,
+ bool iomgr_success) {
+ 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 (iomgr_success) {
+ 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_FATAL_FAILURE;
+ }
+ grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
+ sw->connectivity_state, "reflect_child");
+ if (sw->connectivity_state != GRPC_CHANNEL_FATAL_FAILURE) {
+ 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_channel_element *elem;
+ memset(&op, 0, sizeof(op));
+ 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_channel_element *elem;
+ memset(&op, 0, sizeof(op));
+ 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 */
+ con = grpc_channel_init_create_stack(
+ exec_ctx, GRPC_CLIENT_SUBCHANNEL, 0, c->connecting_result.channel_args, 1,
+ connection_destroy, NULL, c->connecting_result.transport);
+ 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,
+ "connected");
+}
+
+static void on_alarm(grpc_exec_ctx *exec_ctx, void *arg, bool iomgr_success) {
+ grpc_subchannel *c = arg;
+ gpr_mu_lock(&c->mu);
+ c->have_alarm = 0;
+ if (c->disconnected) {
+ iomgr_success = 0;
+ }
+ if (iomgr_success) {
+ 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");
+ }
+}
+
+static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
+ bool iomgr_success) {
+ grpc_subchannel *c = arg;
+
+ 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,
+ "connect_failed");
+ grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, on_alarm, c, now);
+ }
+ gpr_mu_unlock(&c->mu);
+ GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
+}
+
+/*
+ * grpc_subchannel_call implementation
+ */
+
+static void subchannel_call_destroy(grpc_exec_ctx *exec_ctx, void *call,
+ bool success) {
+ grpc_subchannel_call *c = call;
+ GPR_TIMER_BEGIN("grpc_subchannel_call_unref.destroy", 0);
+ grpc_call_stack_destroy(exec_ctx, SUBCHANNEL_CALL_TO_CALL_STACK(c));
+ GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, c->connection, "subchannel_call");
+ gpr_free(c);
+ 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) {
+ 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);
+}
+
+grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
+ grpc_subchannel *c) {
+ return GET_CONNECTED_SUBCHANNEL(c, acq);
+}
+
+grpc_subchannel_call *grpc_connected_subchannel_create_call(
+ grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
+ grpc_pollset *pollset) {
+ grpc_channel_stack *chanstk = CHANNEL_STACK_FROM_CONNECTION(con);
+ grpc_subchannel_call *call =
+ gpr_malloc(sizeof(grpc_subchannel_call) + chanstk->call_stack_size);
+ grpc_call_stack *callstk = SUBCHANNEL_CALL_TO_CALL_STACK(call);
+ call->connection = con;
+ GRPC_CONNECTED_SUBCHANNEL_REF(con, "subchannel_call");
+ grpc_call_stack_init(exec_ctx, chanstk, 1, subchannel_call_destroy, call,
+ NULL, NULL, callstk);
+ grpc_call_stack_set_pollset(exec_ctx, callstk, pollset);
+ return call;
+}
+
+grpc_call_stack *grpc_subchannel_call_get_call_stack(
+ grpc_subchannel_call *subchannel_call) {
+ return SUBCHANNEL_CALL_TO_CALL_STACK(subchannel_call);
+}