--- /dev/null
+/*
+ *
+ * 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 <grpc/support/port_platform.h>
+
+#include "src/core/ext/filters/max_age/max_age_filter.h"
+
+#include <limits.h>
+#include <string.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/channel_stack_builder.h"
+#include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/surface/channel_init.h"
+#include "src/core/lib/transport/http2_errors.h"
+
+#define DEFAULT_MAX_CONNECTION_AGE_MS INT_MAX
+#define DEFAULT_MAX_CONNECTION_AGE_GRACE_MS INT_MAX
+#define DEFAULT_MAX_CONNECTION_IDLE_MS INT_MAX
+#define MAX_CONNECTION_AGE_JITTER 0.1
+
+#define MAX_CONNECTION_AGE_INTEGER_OPTIONS \
+ { DEFAULT_MAX_CONNECTION_AGE_MS, 1, INT_MAX }
+#define MAX_CONNECTION_IDLE_INTEGER_OPTIONS \
+ { DEFAULT_MAX_CONNECTION_IDLE_MS, 1, INT_MAX }
+
+/* States for idle_state in channel_data */
+#define MAX_IDLE_STATE_INIT ((gpr_atm)0)
+#define MAX_IDLE_STATE_SEEN_EXIT_IDLE ((gpr_atm)1)
+#define MAX_IDLE_STATE_SEEN_ENTER_IDLE ((gpr_atm)2)
+#define MAX_IDLE_STATE_TIMER_SET ((gpr_atm)3)
+
+namespace {
+struct channel_data {
+ /* The channel stack to which we take refs for pending callbacks. */
+ grpc_channel_stack* channel_stack;
+ /* Guards access to max_age_timer, max_age_timer_pending, max_age_grace_timer
+ and max_age_grace_timer_pending */
+ gpr_mu max_age_timer_mu;
+ /* True if the max_age timer callback is currently pending */
+ bool max_age_timer_pending;
+ /* True if the max_age_grace timer callback is currently pending */
+ bool max_age_grace_timer_pending;
+ /* The timer for checking if the channel has reached its max age */
+ grpc_timer max_age_timer;
+ /* The timer for checking if the max-aged channel has uesed up the grace
+ period */
+ grpc_timer max_age_grace_timer;
+ /* The timer for checking if the channel's idle duration reaches
+ max_connection_idle */
+ grpc_timer max_idle_timer;
+ /* Allowed max time a channel may have no outstanding rpcs */
+ grpc_millis max_connection_idle;
+ /* Allowed max time a channel may exist */
+ grpc_millis max_connection_age;
+ /* Allowed grace period after the channel reaches its max age */
+ grpc_millis max_connection_age_grace;
+ /* Closure to run when the channel's idle duration reaches max_connection_idle
+ and should be closed gracefully */
+ grpc_closure max_idle_timer_cb;
+ /* Closure to run when the channel reaches its max age and should be closed
+ gracefully */
+ grpc_closure close_max_age_channel;
+ /* Closure to run the channel uses up its max age grace time and should be
+ closed forcibly */
+ grpc_closure force_close_max_age_channel;
+ /* Closure to run when the init fo channel stack is done and the max_idle
+ timer should be started */
+ grpc_closure start_max_idle_timer_after_init;
+ /* Closure to run when the init fo channel stack is done and the max_age timer
+ should be started */
+ grpc_closure start_max_age_timer_after_init;
+ /* Closure to run when the goaway op is finished and the max_age_timer */
+ grpc_closure start_max_age_grace_timer_after_goaway_op;
+ /* Closure to run when the channel connectivity state changes */
+ grpc_closure channel_connectivity_changed;
+ /* Records the current connectivity state */
+ grpc_connectivity_state connectivity_state;
+ /* Number of active calls */
+ gpr_atm call_count;
+ /* TODO(zyc): C++lize this state machine */
+ /* 'idle_state' holds the states of max_idle_timer and channel idleness.
+ It can contain one of the following values:
+ +--------------------------------+----------------+---------+
+ | idle_state | max_idle_timer | channel |
+ +--------------------------------+----------------+---------+
+ | MAX_IDLE_STATE_INIT | unset | busy |
+ | MAX_IDLE_STATE_TIMER_SET | set, valid | idle |
+ | MAX_IDLE_STATE_SEEN_EXIT_IDLE | set, invalid | busy |
+ | MAX_IDLE_STATE_SEEN_ENTER_IDLE | set, invalid | idle |
+ +--------------------------------+----------------+---------+
+
+ MAX_IDLE_STATE_INIT: The initial and final state of 'idle_state'. The
+ channel has 1 or 1+ active calls, and the timer is not set. Note that
+ we may put a virtual call to hold this state at channel initialization or
+ shutdown, so that the channel won't enter other states.
+
+ MAX_IDLE_STATE_TIMER_SET: The state after the timer is set and no calls
+ have arrived after the timer is set. The channel must have 0 active call in
+ this state. If the timer is fired in this state, we will close the channel
+ due to idleness.
+
+ MAX_IDLE_STATE_SEEN_EXIT_IDLE: The state after the timer is set and at
+ least one call has arrived after the timer is set. The channel must have 1
+ or 1+ active calls in this state. If the timer is fired in this state, we
+ won't reschudle it.
+
+ MAX_IDLE_STATE_SEEN_ENTER_IDLE: The state after the timer is set and the at
+ least one call has arrived after the timer is set, BUT the channel
+ currently has 0 active calls. If the timer is fired in this state, we will
+ reschudle it.
+
+ max_idle_timer will not be cancelled (unless the channel is shutting down).
+ If the timer callback is called when the max_idle_timer is valid (i.e.
+ idle_state is MAX_IDLE_STATE_TIMER_SET), the channel will be closed due to
+ idleness, otherwise the channel won't be changed.
+
+ State transitions:
+ MAX_IDLE_STATE_INIT <-------3------ MAX_IDLE_STATE_SEEN_EXIT_IDLE
+ ^ | ^ ^ |
+ | | | | |
+ 1 2 +-----------4------------+ 6 7
+ | | | | |
+ | v | | v
+ MAX_IDLE_STATE_TIMER_SET <----5------ MAX_IDLE_STATE_SEEN_ENTER_IDLE
+
+ For 1, 3, 5 : See max_idle_timer_cb() function
+ For 2, 7 : See decrease_call_count() function
+ For 4, 6 : See increase_call_count() function */
+ gpr_atm idle_state;
+ /* Time when the channel finished its last outstanding call, in grpc_millis */
+ gpr_atm last_enter_idle_time_millis;
+};
+} // namespace
+
+/* Increase the nubmer of active calls. Before the increasement, if there are no
+ calls, the max_idle_timer should be cancelled. */
+static void increase_call_count(channel_data* chand) {
+ /* Exit idle */
+ if (gpr_atm_full_fetch_add(&chand->call_count, 1) == 0) {
+ while (true) {
+ gpr_atm idle_state = gpr_atm_acq_load(&chand->idle_state);
+ switch (idle_state) {
+ case MAX_IDLE_STATE_TIMER_SET:
+ /* max_idle_timer_cb may have already set idle_state to
+ MAX_IDLE_STATE_INIT, in this case, we don't need to set it to
+ MAX_IDLE_STATE_SEEN_EXIT_IDLE */
+ gpr_atm_rel_cas(&chand->idle_state, MAX_IDLE_STATE_TIMER_SET,
+ MAX_IDLE_STATE_SEEN_EXIT_IDLE);
+ return;
+ case MAX_IDLE_STATE_SEEN_ENTER_IDLE:
+ gpr_atm_rel_store(&chand->idle_state, MAX_IDLE_STATE_SEEN_EXIT_IDLE);
+ return;
+ default:
+ /* try again */
+ break;
+ }
+ }
+ }
+}
+
+/* Decrease the nubmer of active calls. After the decrement, if there are no
+ calls, the max_idle_timer should be started. */
+static void decrease_call_count(channel_data* chand) {
+ /* Enter idle */
+ if (gpr_atm_full_fetch_add(&chand->call_count, -1) == 1) {
+ gpr_atm_no_barrier_store(&chand->last_enter_idle_time_millis,
+ (gpr_atm)grpc_core::ExecCtx::Get()->Now());
+ while (true) {
+ gpr_atm idle_state = gpr_atm_acq_load(&chand->idle_state);
+ switch (idle_state) {
+ case MAX_IDLE_STATE_INIT:
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack,
+ "max_age max_idle_timer");
+ grpc_timer_init(
+ &chand->max_idle_timer,
+ grpc_core::ExecCtx::Get()->Now() + chand->max_connection_idle,
+ &chand->max_idle_timer_cb);
+ gpr_atm_rel_store(&chand->idle_state, MAX_IDLE_STATE_TIMER_SET);
+ return;
+ case MAX_IDLE_STATE_SEEN_EXIT_IDLE:
+ if (gpr_atm_rel_cas(&chand->idle_state, MAX_IDLE_STATE_SEEN_EXIT_IDLE,
+ MAX_IDLE_STATE_SEEN_ENTER_IDLE)) {
+ return;
+ }
+ break;
+ default:
+ /* try again */
+ break;
+ }
+ }
+ }
+}
+
+static void start_max_idle_timer_after_init(void* arg, grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ /* Decrease call_count. If there are no active calls at this time,
+ max_idle_timer will start here. If the number of active calls is not 0,
+ max_idle_timer will start after all the active calls end. */
+ decrease_call_count(chand);
+ GRPC_CHANNEL_STACK_UNREF(chand->channel_stack,
+ "max_age start_max_idle_timer_after_init");
+}
+
+static void start_max_age_timer_after_init(void* arg, grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ gpr_mu_lock(&chand->max_age_timer_mu);
+ chand->max_age_timer_pending = true;
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack, "max_age max_age_timer");
+ grpc_timer_init(&chand->max_age_timer,
+ grpc_core::ExecCtx::Get()->Now() + chand->max_connection_age,
+ &chand->close_max_age_channel);
+ gpr_mu_unlock(&chand->max_age_timer_mu);
+ grpc_transport_op* op = grpc_make_transport_op(nullptr);
+ op->on_connectivity_state_change = &chand->channel_connectivity_changed;
+ op->connectivity_state = &chand->connectivity_state;
+ grpc_channel_next_op(grpc_channel_stack_element(chand->channel_stack, 0), op);
+ GRPC_CHANNEL_STACK_UNREF(chand->channel_stack,
+ "max_age start_max_age_timer_after_init");
+}
+
+static void start_max_age_grace_timer_after_goaway_op(void* arg,
+ grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ gpr_mu_lock(&chand->max_age_timer_mu);
+ chand->max_age_grace_timer_pending = true;
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack, "max_age max_age_grace_timer");
+ grpc_timer_init(
+ &chand->max_age_grace_timer,
+ chand->max_connection_age_grace == GRPC_MILLIS_INF_FUTURE
+ ? GRPC_MILLIS_INF_FUTURE
+ : grpc_core::ExecCtx::Get()->Now() + chand->max_connection_age_grace,
+ &chand->force_close_max_age_channel);
+ gpr_mu_unlock(&chand->max_age_timer_mu);
+ GRPC_CHANNEL_STACK_UNREF(chand->channel_stack,
+ "max_age start_max_age_grace_timer_after_goaway_op");
+}
+
+static void close_max_idle_channel(channel_data* chand) {
+ /* Prevent the max idle timer from being set again */
+ gpr_atm_no_barrier_fetch_add(&chand->call_count, 1);
+ grpc_transport_op* op = grpc_make_transport_op(nullptr);
+ op->goaway_error =
+ grpc_error_set_int(GRPC_ERROR_CREATE_FROM_STATIC_STRING("max_idle"),
+ GRPC_ERROR_INT_HTTP2_ERROR, GRPC_HTTP2_NO_ERROR);
+ grpc_channel_element* elem =
+ grpc_channel_stack_element(chand->channel_stack, 0);
+ elem->filter->start_transport_op(elem, op);
+}
+
+static void max_idle_timer_cb(void* arg, grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ if (error == GRPC_ERROR_NONE) {
+ bool try_again = true;
+ while (try_again) {
+ gpr_atm idle_state = gpr_atm_acq_load(&chand->idle_state);
+ switch (idle_state) {
+ case MAX_IDLE_STATE_TIMER_SET:
+ close_max_idle_channel(chand);
+ /* This MAX_IDLE_STATE_INIT is a final state, we don't have to check
+ * if idle_state has been changed */
+ gpr_atm_rel_store(&chand->idle_state, MAX_IDLE_STATE_INIT);
+ try_again = false;
+ break;
+ case MAX_IDLE_STATE_SEEN_EXIT_IDLE:
+ if (gpr_atm_rel_cas(&chand->idle_state, MAX_IDLE_STATE_SEEN_EXIT_IDLE,
+ MAX_IDLE_STATE_INIT)) {
+ try_again = false;
+ }
+ break;
+ case MAX_IDLE_STATE_SEEN_ENTER_IDLE:
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack,
+ "max_age max_idle_timer");
+ grpc_timer_init(&chand->max_idle_timer,
+ static_cast<grpc_millis>(gpr_atm_no_barrier_load(
+ &chand->last_enter_idle_time_millis)) +
+ chand->max_connection_idle,
+ &chand->max_idle_timer_cb);
+ /* idle_state may have already been set to
+ MAX_IDLE_STATE_SEEN_EXIT_IDLE by increase_call_count(), in this
+ case, we don't need to set it to MAX_IDLE_STATE_TIMER_SET */
+ gpr_atm_rel_cas(&chand->idle_state, MAX_IDLE_STATE_SEEN_ENTER_IDLE,
+ MAX_IDLE_STATE_TIMER_SET);
+ try_again = false;
+ break;
+ default:
+ /* try again */
+ break;
+ }
+ }
+ }
+ GRPC_CHANNEL_STACK_UNREF(chand->channel_stack, "max_age max_idle_timer");
+}
+
+static void close_max_age_channel(void* arg, grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ gpr_mu_lock(&chand->max_age_timer_mu);
+ chand->max_age_timer_pending = false;
+ gpr_mu_unlock(&chand->max_age_timer_mu);
+ if (error == GRPC_ERROR_NONE) {
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack,
+ "max_age start_max_age_grace_timer_after_goaway_op");
+ grpc_transport_op* op = grpc_make_transport_op(
+ &chand->start_max_age_grace_timer_after_goaway_op);
+ op->goaway_error =
+ grpc_error_set_int(GRPC_ERROR_CREATE_FROM_STATIC_STRING("max_age"),
+ GRPC_ERROR_INT_HTTP2_ERROR, GRPC_HTTP2_NO_ERROR);
+ grpc_channel_element* elem =
+ grpc_channel_stack_element(chand->channel_stack, 0);
+ elem->filter->start_transport_op(elem, op);
+ } else if (error != GRPC_ERROR_CANCELLED) {
+ GRPC_LOG_IF_ERROR("close_max_age_channel", error);
+ }
+ GRPC_CHANNEL_STACK_UNREF(chand->channel_stack, "max_age max_age_timer");
+}
+
+static void force_close_max_age_channel(void* arg, grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ gpr_mu_lock(&chand->max_age_timer_mu);
+ chand->max_age_grace_timer_pending = false;
+ gpr_mu_unlock(&chand->max_age_timer_mu);
+ if (error == GRPC_ERROR_NONE) {
+ grpc_transport_op* op = grpc_make_transport_op(nullptr);
+ op->disconnect_with_error =
+ GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel reaches max age");
+ grpc_channel_element* elem =
+ grpc_channel_stack_element(chand->channel_stack, 0);
+ elem->filter->start_transport_op(elem, op);
+ } else if (error != GRPC_ERROR_CANCELLED) {
+ GRPC_LOG_IF_ERROR("force_close_max_age_channel", error);
+ }
+ GRPC_CHANNEL_STACK_UNREF(chand->channel_stack, "max_age max_age_grace_timer");
+}
+
+static void channel_connectivity_changed(void* arg, grpc_error* error) {
+ channel_data* chand = static_cast<channel_data*>(arg);
+ if (chand->connectivity_state != GRPC_CHANNEL_SHUTDOWN) {
+ grpc_transport_op* op = grpc_make_transport_op(nullptr);
+ op->on_connectivity_state_change = &chand->channel_connectivity_changed;
+ op->connectivity_state = &chand->connectivity_state;
+ grpc_channel_next_op(grpc_channel_stack_element(chand->channel_stack, 0),
+ op);
+ } else {
+ gpr_mu_lock(&chand->max_age_timer_mu);
+ if (chand->max_age_timer_pending) {
+ grpc_timer_cancel(&chand->max_age_timer);
+ chand->max_age_timer_pending = false;
+ }
+ if (chand->max_age_grace_timer_pending) {
+ grpc_timer_cancel(&chand->max_age_grace_timer);
+ chand->max_age_grace_timer_pending = false;
+ }
+ gpr_mu_unlock(&chand->max_age_timer_mu);
+ /* If there are no active calls, this increasement will cancel
+ max_idle_timer, and prevent max_idle_timer from being started in the
+ future. */
+ increase_call_count(chand);
+ if (gpr_atm_acq_load(&chand->idle_state) == MAX_IDLE_STATE_SEEN_EXIT_IDLE) {
+ grpc_timer_cancel(&chand->max_idle_timer);
+ }
+ }
+}
+
+/* A random jitter of +/-10% will be added to MAX_CONNECTION_AGE to spread out
+ connection storms. Note that the MAX_CONNECTION_AGE option without jitter
+ would not create connection storms by itself, but if there happened to be a
+ connection storm it could cause it to repeat at a fixed period. */
+static grpc_millis
+add_random_max_connection_age_jitter_and_convert_to_grpc_millis(int value) {
+ /* generate a random number between 1 - MAX_CONNECTION_AGE_JITTER and
+ 1 + MAX_CONNECTION_AGE_JITTER */
+ double multiplier = rand() * MAX_CONNECTION_AGE_JITTER * 2.0 / RAND_MAX +
+ 1.0 - MAX_CONNECTION_AGE_JITTER;
+ double result = multiplier * value;
+ /* INT_MAX - 0.5 converts the value to float, so that result will not be
+ cast to int implicitly before the comparison. */
+ return result > (static_cast<double>(GRPC_MILLIS_INF_FUTURE)) - 0.5
+ ? GRPC_MILLIS_INF_FUTURE
+ : static_cast<grpc_millis>(result);
+}
+
+/* Constructor for call_data. */
+static grpc_error* init_call_elem(grpc_call_element* elem,
+ const grpc_call_element_args* args) {
+ channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+ increase_call_count(chand);
+ return GRPC_ERROR_NONE;
+}
+
+/* Destructor for call_data. */
+static void destroy_call_elem(grpc_call_element* elem,
+ const grpc_call_final_info* final_info,
+ grpc_closure* ignored) {
+ channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+ decrease_call_count(chand);
+}
+
+/* Constructor for channel_data. */
+static grpc_error* init_channel_elem(grpc_channel_element* elem,
+ grpc_channel_element_args* args) {
+ channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+ gpr_mu_init(&chand->max_age_timer_mu);
+ chand->max_age_timer_pending = false;
+ chand->max_age_grace_timer_pending = false;
+ chand->channel_stack = args->channel_stack;
+ chand->max_connection_age =
+ add_random_max_connection_age_jitter_and_convert_to_grpc_millis(
+ DEFAULT_MAX_CONNECTION_AGE_MS);
+ chand->max_connection_age_grace =
+ DEFAULT_MAX_CONNECTION_AGE_GRACE_MS == INT_MAX
+ ? GRPC_MILLIS_INF_FUTURE
+ : DEFAULT_MAX_CONNECTION_AGE_GRACE_MS;
+ chand->max_connection_idle = DEFAULT_MAX_CONNECTION_IDLE_MS == INT_MAX
+ ? GRPC_MILLIS_INF_FUTURE
+ : DEFAULT_MAX_CONNECTION_IDLE_MS;
+ chand->idle_state = MAX_IDLE_STATE_INIT;
+ gpr_atm_no_barrier_store(&chand->last_enter_idle_time_millis, GPR_ATM_MIN);
+ for (size_t i = 0; i < args->channel_args->num_args; ++i) {
+ if (0 == strcmp(args->channel_args->args[i].key,
+ GRPC_ARG_MAX_CONNECTION_AGE_MS)) {
+ const int value = grpc_channel_arg_get_integer(
+ &args->channel_args->args[i], MAX_CONNECTION_AGE_INTEGER_OPTIONS);
+ chand->max_connection_age =
+ add_random_max_connection_age_jitter_and_convert_to_grpc_millis(
+ value);
+ } else if (0 == strcmp(args->channel_args->args[i].key,
+ GRPC_ARG_MAX_CONNECTION_AGE_GRACE_MS)) {
+ const int value = grpc_channel_arg_get_integer(
+ &args->channel_args->args[i],
+ {DEFAULT_MAX_CONNECTION_AGE_GRACE_MS, 0, INT_MAX});
+ chand->max_connection_age_grace =
+ value == INT_MAX ? GRPC_MILLIS_INF_FUTURE : value;
+ } else if (0 == strcmp(args->channel_args->args[i].key,
+ GRPC_ARG_MAX_CONNECTION_IDLE_MS)) {
+ const int value = grpc_channel_arg_get_integer(
+ &args->channel_args->args[i], MAX_CONNECTION_IDLE_INTEGER_OPTIONS);
+ chand->max_connection_idle =
+ value == INT_MAX ? GRPC_MILLIS_INF_FUTURE : value;
+ }
+ }
+ GRPC_CLOSURE_INIT(&chand->max_idle_timer_cb, max_idle_timer_cb, chand,
+ grpc_schedule_on_exec_ctx);
+ GRPC_CLOSURE_INIT(&chand->close_max_age_channel, close_max_age_channel, chand,
+ grpc_schedule_on_exec_ctx);
+ GRPC_CLOSURE_INIT(&chand->force_close_max_age_channel,
+ force_close_max_age_channel, chand,
+ grpc_schedule_on_exec_ctx);
+ GRPC_CLOSURE_INIT(&chand->start_max_idle_timer_after_init,
+ start_max_idle_timer_after_init, chand,
+ grpc_schedule_on_exec_ctx);
+ GRPC_CLOSURE_INIT(&chand->start_max_age_timer_after_init,
+ start_max_age_timer_after_init, chand,
+ grpc_schedule_on_exec_ctx);
+ GRPC_CLOSURE_INIT(&chand->start_max_age_grace_timer_after_goaway_op,
+ start_max_age_grace_timer_after_goaway_op, chand,
+ grpc_schedule_on_exec_ctx);
+ GRPC_CLOSURE_INIT(&chand->channel_connectivity_changed,
+ channel_connectivity_changed, chand,
+ grpc_schedule_on_exec_ctx);
+
+ if (chand->max_connection_age != GRPC_MILLIS_INF_FUTURE) {
+ /* When the channel reaches its max age, we send down an op with
+ goaway_error set. However, we can't send down any ops until after the
+ channel stack is fully initialized. If we start the timer here, we have
+ no guarantee that the timer won't pop before channel stack initialization
+ is finished. To avoid that problem, we create a closure to start the
+ timer, and we schedule that closure to be run after call stack
+ initialization is done. */
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack,
+ "max_age start_max_age_timer_after_init");
+ GRPC_CLOSURE_SCHED(&chand->start_max_age_timer_after_init, GRPC_ERROR_NONE);
+ }
+
+ /* Initialize the number of calls as 1, so that the max_idle_timer will not
+ start until start_max_idle_timer_after_init is invoked. */
+ gpr_atm_rel_store(&chand->call_count, 1);
+ if (chand->max_connection_idle != GRPC_MILLIS_INF_FUTURE) {
+ GRPC_CHANNEL_STACK_REF(chand->channel_stack,
+ "max_age start_max_idle_timer_after_init");
+ GRPC_CLOSURE_SCHED(&chand->start_max_idle_timer_after_init,
+ GRPC_ERROR_NONE);
+ }
+ return GRPC_ERROR_NONE;
+}
+
+/* Destructor for channel_data. */
+static void destroy_channel_elem(grpc_channel_element* elem) {
+ channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+ gpr_mu_destroy(&chand->max_age_timer_mu);
+}
+
+const grpc_channel_filter grpc_max_age_filter = {
+ grpc_call_next_op,
+ grpc_channel_next_op,
+ 0, /* sizeof_call_data */
+ init_call_elem,
+ grpc_call_stack_ignore_set_pollset_or_pollset_set,
+ destroy_call_elem,
+ sizeof(channel_data),
+ init_channel_elem,
+ destroy_channel_elem,
+ grpc_channel_next_get_info,
+ "max_age"};
+
+static bool maybe_add_max_age_filter(grpc_channel_stack_builder* builder,
+ void* arg) {
+ const grpc_channel_args* channel_args =
+ grpc_channel_stack_builder_get_channel_arguments(builder);
+ bool enable =
+ grpc_channel_arg_get_integer(
+ grpc_channel_args_find(channel_args, GRPC_ARG_MAX_CONNECTION_AGE_MS),
+ MAX_CONNECTION_AGE_INTEGER_OPTIONS) != INT_MAX ||
+ grpc_channel_arg_get_integer(
+ grpc_channel_args_find(channel_args, GRPC_ARG_MAX_CONNECTION_IDLE_MS),
+ MAX_CONNECTION_IDLE_INTEGER_OPTIONS) != INT_MAX;
+ if (enable) {
+ return grpc_channel_stack_builder_prepend_filter(
+ builder, &grpc_max_age_filter, nullptr, nullptr);
+ } else {
+ return true;
+ }
+}
+
+void grpc_max_age_filter_init(void) {
+ grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
+ GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+ maybe_add_max_age_filter, nullptr);
+}
+
+void grpc_max_age_filter_shutdown(void) {}