diff options
Diffstat (limited to 'src/core/ext/filters/client_channel/subchannel.cc')
| -rw-r--r-- | src/core/ext/filters/client_channel/subchannel.cc | 814 |
1 files changed, 814 insertions, 0 deletions
diff --git a/src/core/ext/filters/client_channel/subchannel.cc b/src/core/ext/filters/client_channel/subchannel.cc new file mode 100644 index 0000000000..bff5001d69 --- /dev/null +++ b/src/core/ext/filters/client_channel/subchannel.cc @@ -0,0 +1,814 @@ +/* + * + * Copyright 2015 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/client_channel/subchannel.h" + +#include <inttypes.h> +#include <limits.h> +#include <string.h> + +#include <grpc/support/alloc.h> +#include <grpc/support/avl.h> +#include <grpc/support/string_util.h> + +#include "src/core/ext/filters/client_channel/client_channel.h" +#include "src/core/ext/filters/client_channel/parse_address.h" +#include "src/core/ext/filters/client_channel/proxy_mapper_registry.h" +#include "src/core/ext/filters/client_channel/subchannel_index.h" +#include "src/core/ext/filters/client_channel/uri_parser.h" +#include "src/core/lib/channel/channel_args.h" +#include "src/core/lib/channel/connected_channel.h" +#include "src/core/lib/debug/stats.h" +#include "src/core/lib/iomgr/sockaddr_utils.h" +#include "src/core/lib/iomgr/timer.h" +#include "src/core/lib/profiling/timers.h" +#include "src/core/lib/slice/slice_internal.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_INITIAL_CONNECT_BACKOFF_SECONDS 1 +#define GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER 1.6 +#define GRPC_SUBCHANNEL_RECONNECT_MIN_BACKOFF_SECONDS 20 +#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; + + grpc_subchannel_key *key; + + /** set during connection */ + grpc_connect_out_args connecting_result; + + /** callback for connection finishing */ + grpc_closure connected; + + /** callback for our alarm */ + grpc_closure on_alarm; + + /** 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? */ + bool disconnected; + /** are we connecting */ + bool 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? */ + bool have_alarm; + /** have we started the backoff loop */ + bool backoff_begun; + /** our alarm */ + grpc_timer alarm; +}; + +struct grpc_subchannel_call { + grpc_connected_subchannel *connection; + grpc_closure *schedule_closure_after_destroy; +}; + +#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); + +#ifndef NDEBUG +#define REF_REASON 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_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 = (grpc_connected_subchannel *)arg; + grpc_channel_stack_destroy(exec_ctx, CHANNEL_STACK_FROM_CONNECTION(c)); + gpr_free(c); +} + +grpc_connected_subchannel *grpc_connected_subchannel_ref( + grpc_connected_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) { + GRPC_CHANNEL_STACK_REF(CHANNEL_STACK_FROM_CONNECTION(c), REF_REASON); + return c; +} + +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 = (grpc_subchannel *)arg; + gpr_free((void *)c->filters); + grpc_channel_args_destroy(exec_ctx, c->args); + grpc_connectivity_state_destroy(exec_ctx, &c->state_tracker); + grpc_connector_unref(exec_ctx, c->connector); + grpc_pollset_set_destroy(exec_ctx, c->pollset_set); + grpc_subchannel_key_destroy(exec_ctx, c->key); + gpr_mu_destroy(&c->mu); + 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); +#ifndef NDEBUG + if (GRPC_TRACER_ON(grpc_trace_stream_refcount)) { + gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, + "SUBCHANNEL: %p %12s 0x%" PRIxPTR " -> 0x%" 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 = true; + grpc_connector_shutdown( + exec_ctx, c->connector, + GRPC_ERROR_CREATE_FROM_STATIC_STRING("Subchannel disconnected")); + 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; + // add a weak ref and subtract a strong ref (atomically) + 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_CLOSURE_SCHED(exec_ctx, GRPC_CLOSURE_CREATE(subchannel_destroy, c, + grpc_schedule_on_exec_ctx), + GRPC_ERROR_NONE); + } +} + +grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx, + grpc_connector *connector, + const grpc_subchannel_args *args) { + grpc_subchannel_key *key = grpc_subchannel_key_create(args); + grpc_subchannel *c = grpc_subchannel_index_find(exec_ctx, key); + if (c) { + grpc_subchannel_key_destroy(exec_ctx, key); + return c; + } + + GRPC_STATS_INC_CLIENT_SUBCHANNELS_CREATED(exec_ctx); + c = (grpc_subchannel *)gpr_zalloc(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 = (const grpc_channel_filter **)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->pollset_set = grpc_pollset_set_create(); + grpc_resolved_address *addr = + (grpc_resolved_address *)gpr_malloc(sizeof(*addr)); + grpc_get_subchannel_address_arg(exec_ctx, args->args, addr); + grpc_resolved_address *new_address = NULL; + grpc_channel_args *new_args = NULL; + if (grpc_proxy_mappers_map_address(exec_ctx, addr, args->args, &new_address, + &new_args)) { + GPR_ASSERT(new_address != NULL); + gpr_free(addr); + addr = new_address; + } + static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS}; + grpc_arg new_arg = grpc_create_subchannel_address_arg(addr); + gpr_free(addr); + c->args = grpc_channel_args_copy_and_add_and_remove( + new_args != NULL ? new_args : args->args, keys_to_remove, + GPR_ARRAY_SIZE(keys_to_remove), &new_arg, 1); + gpr_free(new_arg.value.string); + if (new_args != NULL) grpc_channel_args_destroy(exec_ctx, new_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_schedule_on_exec_ctx); + grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE, + "subchannel"); + int initial_backoff_ms = + GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000; + int min_backoff_ms = GRPC_SUBCHANNEL_RECONNECT_MIN_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_ms")) { + fixed_reconnect_backoff = true; + initial_backoff_ms = min_backoff_ms = max_backoff_ms = + grpc_channel_arg_get_integer(&c->args->args[i], + {initial_backoff_ms, 100, INT_MAX}); + } else if (0 == strcmp(c->args->args[i].key, + GRPC_ARG_MIN_RECONNECT_BACKOFF_MS)) { + fixed_reconnect_backoff = false; + min_backoff_ms = grpc_channel_arg_get_integer( + &c->args->args[i], {min_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], {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], {initial_backoff_ms, 100, INT_MAX}); + } + } + } + gpr_backoff_init( + &c->backoff_state, initial_backoff_ms, + fixed_reconnect_backoff ? 1.0 + : GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER, + fixed_reconnect_backoff ? 0.0 : GRPC_SUBCHANNEL_RECONNECT_JITTER, + min_backoff_ms, max_backoff_ms); + gpr_mu_init(&c->mu); + + return grpc_subchannel_index_register(exec_ctx, key, c); +} + +static void continue_connect_locked(grpc_exec_ctx *exec_ctx, + grpc_subchannel *c) { + grpc_connect_in_args args; + + args.interested_parties = c->pollset_set; + args.deadline = c->next_attempt; + args.channel_args = c->args; + + 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); +} + +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_get(&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 = (external_state_watcher *)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); + GRPC_CLOSURE_RUN(exec_ctx, follow_up, GRPC_ERROR_REF(error)); +} + +static void on_alarm(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { + grpc_subchannel *c = (grpc_subchannel *)arg; + gpr_mu_lock(&c->mu); + c->have_alarm = false; + if (c->disconnected) { + error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING("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_locked(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 maybe_start_connecting_locked(grpc_exec_ctx *exec_ctx, + grpc_subchannel *c) { + if (c->disconnected) { + /* Don't try to connect if we're already disconnected */ + return; + } + + if (c->connecting) { + /* Already connecting: don't restart */ + return; + } + + if (GET_CONNECTED_SUBCHANNEL(c, no_barrier) != NULL) { + /* Already connected: don't restart */ + return; + } + + if (!grpc_connectivity_state_has_watchers(&c->state_tracker)) { + /* Nobody is interested in connecting: so don't just yet */ + return; + } + + c->connecting = true; + GRPC_SUBCHANNEL_WEAK_REF(c, "connecting"); + + gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC); + if (!c->backoff_begun) { + c->backoff_begun = true; + c->next_attempt = gpr_backoff_begin(&c->backoff_state, now); + continue_connect_locked(exec_ctx, c); + } else { + GPR_ASSERT(!c->have_alarm); + c->have_alarm = true; + gpr_timespec time_til_next = gpr_time_sub(c->next_attempt, now); + 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_CLOSURE_INIT(&c->on_alarm, on_alarm, c, grpc_schedule_on_exec_ctx); + grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, &c->on_alarm, now); + } +} + +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 = (external_state_watcher *)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, + grpc_schedule_on_exec_ctx); + 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; + grpc_connectivity_state_notify_on_state_change(exec_ctx, &c->state_tracker, + state, &w->closure); + maybe_start_connecting_locked(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 = (state_watcher *)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 bool 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( + exec_ctx, 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)) { + grpc_channel_stack_builder_destroy(exec_ctx, builder); + return false; + } + grpc_error *error = grpc_channel_stack_builder_finish( + exec_ctx, builder, 0, 1, connection_destroy, NULL, (void **)&con); + if (error != GRPC_ERROR_NONE) { + grpc_transport_destroy(exec_ctx, c->connecting_result.transport); + gpr_log(GPR_ERROR, "error initializing subchannel stack: %s", + grpc_error_string(error)); + GRPC_ERROR_UNREF(error); + return false; + } + stk = CHANNEL_STACK_FROM_CONNECTION(con); + memset(&c->connecting_result, 0, sizeof(c->connecting_result)); + + /* initialize state watcher */ + sw_subchannel = (state_watcher *)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, grpc_schedule_on_exec_ctx); + + if (c->disconnected) { + gpr_free(sw_subchannel); + grpc_channel_stack_destroy(exec_ctx, stk); + gpr_free(con); + return false; + } + + /* 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)); + + /* 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"); + return true; +} + +static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg, + grpc_error *error) { + grpc_subchannel *c = (grpc_subchannel *)arg; + grpc_channel_args *delete_channel_args = c->connecting_result.channel_args; + + GRPC_SUBCHANNEL_WEAK_REF(c, "connected"); + gpr_mu_lock(&c->mu); + c->connecting = false; + if (c->connecting_result.transport != NULL && + publish_transport_locked(exec_ctx, c)) { + /* do nothing, transport was published */ + } else if (c->disconnected) { + GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting"); + } else { + grpc_connectivity_state_set( + exec_ctx, &c->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE, + grpc_error_set_int(GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( + "Connect Failed", &error, 1), + GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE), + "connect_failed"); + + const char *errmsg = grpc_error_string(error); + gpr_log(GPR_INFO, "Connect failed: %s", errmsg); + + maybe_start_connecting_locked(exec_ctx, c); + GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting"); + } + gpr_mu_unlock(&c->mu); + GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connected"); + grpc_channel_args_destroy(exec_ctx, 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 = (grpc_subchannel_call *)call; + GPR_ASSERT(c->schedule_closure_after_destroy != NULL); + 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->schedule_closure_after_destroy); + GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, connection, "subchannel_call"); + GPR_TIMER_END("grpc_subchannel_call_unref.destroy", 0); +} + +void grpc_subchannel_call_set_cleanup_closure(grpc_subchannel_call *call, + grpc_closure *closure) { + GPR_ASSERT(call->schedule_closure_after_destroy == NULL); + GPR_ASSERT(closure != NULL); + call->schedule_closure_after_destroy = closure; +} + +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); +} + +void grpc_subchannel_call_process_op(grpc_exec_ctx *exec_ctx, + grpc_subchannel_call *call, + grpc_transport_stream_op_batch *batch) { + 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); + GRPC_CALL_LOG_OP(GPR_INFO, top_elem, batch); + top_elem->filter->start_transport_stream_op_batch(exec_ctx, top_elem, batch); + 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); +} + +const grpc_subchannel_key *grpc_subchannel_get_key( + const grpc_subchannel *subchannel) { + return subchannel->key; +} + +grpc_error *grpc_connected_subchannel_create_call( + grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con, + const grpc_connected_subchannel_call_args *args, + grpc_subchannel_call **call) { + grpc_channel_stack *chanstk = CHANNEL_STACK_FROM_CONNECTION(con); + *call = (grpc_subchannel_call *)gpr_arena_alloc( + args->arena, sizeof(grpc_subchannel_call) + chanstk->call_stack_size); + grpc_call_stack *callstk = SUBCHANNEL_CALL_TO_CALL_STACK(*call); + (*call)->connection = GRPC_CONNECTED_SUBCHANNEL_REF(con, "subchannel_call"); + const grpc_call_element_args call_args = { + callstk, /* call_stack */ + NULL, /* server_transport_data */ + args->context, /* context */ + args->path, /* path */ + args->start_time, /* start_time */ + args->deadline, /* deadline */ + args->arena, /* arena */ + args->call_combiner /* call_combiner */ + }; + grpc_error *error = grpc_call_stack_init( + exec_ctx, chanstk, 1, subchannel_call_destroy, *call, &call_args); + if (error != GRPC_ERROR_NONE) { + const char *error_string = grpc_error_string(error); + gpr_log(GPR_ERROR, "error: %s", error_string); + return error; + } + grpc_call_stack_set_pollset_or_pollset_set(exec_ctx, callstk, args->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); +} + +static void grpc_uri_to_sockaddr(grpc_exec_ctx *exec_ctx, const char *uri_str, + grpc_resolved_address *addr) { + grpc_uri *uri = grpc_uri_parse(exec_ctx, uri_str, 0 /* suppress_errors */); + GPR_ASSERT(uri != NULL); + if (!grpc_parse_uri(uri, addr)) memset(addr, 0, sizeof(*addr)); + grpc_uri_destroy(uri); +} + +void grpc_get_subchannel_address_arg(grpc_exec_ctx *exec_ctx, + const grpc_channel_args *args, + grpc_resolved_address *addr) { + const char *addr_uri_str = grpc_get_subchannel_address_uri_arg(args); + memset(addr, 0, sizeof(*addr)); + if (*addr_uri_str != '\0') { + grpc_uri_to_sockaddr(exec_ctx, addr_uri_str, addr); + } +} + +const char *grpc_get_subchannel_address_uri_arg(const grpc_channel_args *args) { + const grpc_arg *addr_arg = + grpc_channel_args_find(args, GRPC_ARG_SUBCHANNEL_ADDRESS); + GPR_ASSERT(addr_arg != NULL); // Should have been set by LB policy. + GPR_ASSERT(addr_arg->type == GRPC_ARG_STRING); + return addr_arg->value.string; +} + +grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address *addr) { + return grpc_channel_arg_string_create( + (char *)GRPC_ARG_SUBCHANNEL_ADDRESS, + addr->len > 0 ? grpc_sockaddr_to_uri(addr) : gpr_strdup("")); +} |