text: /*
   *
   * 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 <grpc/support/port_platform.h>
  
  #include "src/core/ext/transport/chttp2/server/chttp2_server.h"
  
  #include <grpc/grpc.h>
  
  #include <inttypes.h>
  #include <limits.h>
  #include <string.h>
  
  #include <grpc/support/alloc.h>
  #include <grpc/support/log.h>
  #include <grpc/support/string_util.h>
  #include <grpc/support/sync.h>
  
  #include "src/core/ext/filters/http/server/http_server_filter.h"
  #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
  #include "src/core/ext/transport/chttp2/transport/internal.h"
  #include "src/core/lib/channel/channel_args.h"
  #include "src/core/lib/channel/handshaker.h"
  #include "src/core/lib/channel/handshaker_registry.h"
  #include "src/core/lib/gpr/host_port.h"
  #include "src/core/lib/iomgr/endpoint.h"
  #include "src/core/lib/iomgr/resolve_address.h"
  #include "src/core/lib/iomgr/resource_quota.h"
  #include "src/core/lib/iomgr/tcp_server.h"
  #include "src/core/lib/iomgr/tcp_posix.h"
  #include "src/core/lib/slice/slice_internal.h"
  #include "src/core/lib/surface/api_trace.h"
  #include "src/core/lib/surface/server.h"
  
  typedef struct {
    grpc_server* server;
    grpc_tcp_server* tcp_server;
    grpc_channel_args* args;
    gpr_mu mu;
    bool shutdown;
    grpc_closure tcp_server_shutdown_complete;
    grpc_closure* server_destroy_listener_done;
    grpc_handshake_manager* pending_handshake_mgrs;
    grpc_core::RefCountedPtr<grpc_core::channelz::ListenSocketNode>
        channelz_listen_socket;
  } server_state;
  
  typedef struct {
    gpr_refcount refs;
    server_state* svr_state;
    grpc_pollset* accepting_pollset;
    grpc_tcp_server_acceptor* acceptor;
    grpc_handshake_manager* handshake_mgr;
    // State for enforcing handshake timeout on receiving HTTP/2 settings.
    grpc_chttp2_transport* transport;
    grpc_millis deadline;
    grpc_timer timer;
    grpc_closure on_timeout;
    grpc_closure on_receive_settings;
    grpc_pollset_set* interested_parties;
  } server_connection_state;
  
  static void server_connection_state_unref(
      server_connection_state* connection_state) {
    if (gpr_unref(&connection_state->refs)) {
      if (connection_state->transport != nullptr) {
        GRPC_CHTTP2_UNREF_TRANSPORT(connection_state->transport,
                                    "receive settings timeout");
      }
      grpc_pollset_set_del_pollset(connection_state->interested_parties,
                                   connection_state->accepting_pollset);
      grpc_pollset_set_destroy(connection_state->interested_parties);
      gpr_free(connection_state);
    }
  }
  
  static void on_timeout(void* arg, grpc_error* error) {
    server_connection_state* connection_state =
        static_cast<server_connection_state*>(arg);
    // Note that we may be called with GRPC_ERROR_NONE when the timer fires
    // or with an error indicating that the timer system is being shut down.
    if (error != GRPC_ERROR_CANCELLED) {
      grpc_transport_op* op = grpc_make_transport_op(nullptr);
      op->disconnect_with_error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
          "Did not receive HTTP/2 settings before handshake timeout");
      grpc_transport_perform_op(&connection_state->transport->base, op);
    }
    server_connection_state_unref(connection_state);
  }
  
  static void on_receive_settings(void* arg, grpc_error* error) {
    server_connection_state* connection_state =
        static_cast<server_connection_state*>(arg);
    if (error == GRPC_ERROR_NONE) {
      grpc_timer_cancel(&connection_state->timer);
    }
    server_connection_state_unref(connection_state);
  }
  
  static void on_handshake_done(void* arg, grpc_error* error) {
    grpc_handshaker_args* args = static_cast<grpc_handshaker_args*>(arg);
    server_connection_state* connection_state =
        static_cast<server_connection_state*>(args->user_data);
    gpr_mu_lock(&connection_state->svr_state->mu);
    grpc_resource_user* resource_user = grpc_server_get_default_resource_user(
        connection_state->svr_state->server);
    if (error != GRPC_ERROR_NONE || connection_state->svr_state->shutdown) {
      const char* error_str = grpc_error_string(error);
      gpr_log(GPR_DEBUG, "Handshaking failed: %s", error_str);
      grpc_resource_user* resource_user = grpc_server_get_default_resource_user(
          connection_state->svr_state->server);
      if (resource_user != nullptr) {
        grpc_resource_user_free(resource_user, GRPC_RESOURCE_QUOTA_CHANNEL_SIZE);
      }
      if (error == GRPC_ERROR_NONE && args->endpoint != nullptr) {
        // We were shut down after handshaking completed successfully, so
        // destroy the endpoint here.
        // TODO(ctiller): It is currently necessary to shutdown endpoints
        // before destroying them, even if we know that there are no
        // pending read/write callbacks.  This should be fixed, at which
        // point this can be removed.
        grpc_endpoint_shutdown(args->endpoint, GRPC_ERROR_NONE);
        grpc_endpoint_destroy(args->endpoint);
        grpc_channel_args_destroy(args->args);
        grpc_slice_buffer_destroy_internal(args->read_buffer);
        gpr_free(args->read_buffer);
      }
    } else {
      // If the handshaking succeeded but there is no endpoint, then the
      // handshaker may have handed off the connection to some external
      // code, so we can just clean up here without creating a transport.
      if (args->endpoint != nullptr) {
        grpc_transport* transport = grpc_create_chttp2_transport(
            args->args, args->endpoint, false, resource_user);
        grpc_server_setup_transport(
            connection_state->svr_state->server, transport,
            connection_state->accepting_pollset, args->args,
            grpc_chttp2_transport_get_socket_node(transport), resource_user);
        // Use notify_on_receive_settings callback to enforce the
        // handshake deadline.
        connection_state->transport =
            reinterpret_cast<grpc_chttp2_transport*>(transport);
        gpr_ref(&connection_state->refs);
        GRPC_CLOSURE_INIT(&connection_state->on_receive_settings,
                          on_receive_settings, connection_state,
                          grpc_schedule_on_exec_ctx);
        grpc_chttp2_transport_start_reading(
            transport, args->read_buffer, &connection_state->on_receive_settings);
        grpc_channel_args_destroy(args->args);
        gpr_ref(&connection_state->refs);
        GRPC_CHTTP2_REF_TRANSPORT((grpc_chttp2_transport*)transport,
                                  "receive settings timeout");
        GRPC_CLOSURE_INIT(&connection_state->on_timeout, on_timeout,
                          connection_state, grpc_schedule_on_exec_ctx);
        grpc_timer_init(&connection_state->timer, connection_state->deadline,
                        &connection_state->on_timeout);
      } else {
        if (resource_user != nullptr) {
          grpc_resource_user_free(resource_user,
                                  GRPC_RESOURCE_QUOTA_CHANNEL_SIZE);
        }
      }
    }
    grpc_handshake_manager_pending_list_remove(
        &connection_state->svr_state->pending_handshake_mgrs,
        connection_state->handshake_mgr);
    gpr_mu_unlock(&connection_state->svr_state->mu);
    grpc_handshake_manager_destroy(connection_state->handshake_mgr);
    gpr_free(connection_state->acceptor);
    grpc_tcp_server_unref(connection_state->svr_state->tcp_server);
    server_connection_state_unref(connection_state);
  }
  
  static void on_accept(void* arg, grpc_endpoint* tcp,
                        grpc_pollset* accepting_pollset,
                        grpc_tcp_server_acceptor* acceptor) {
    server_state* state = static_cast<server_state*>(arg);
    gpr_mu_lock(&state->mu);
    if (state->shutdown) {
      gpr_mu_unlock(&state->mu);
      grpc_endpoint_shutdown(tcp, GRPC_ERROR_NONE);
      grpc_endpoint_destroy(tcp);
      gpr_free(acceptor);
      return;
    }
    grpc_resource_user* resource_user =
        grpc_server_get_default_resource_user(state->server);
    if (resource_user != nullptr &&
        !grpc_resource_user_safe_alloc(resource_user,
                                       GRPC_RESOURCE_QUOTA_CHANNEL_SIZE)) {
      gpr_log(
          GPR_ERROR,
          "Memory quota exhausted, rejecting the connection, no handshaking.");
      gpr_mu_unlock(&state->mu);
      grpc_endpoint_shutdown(tcp, GRPC_ERROR_NONE);
      grpc_endpoint_destroy(tcp);
      gpr_free(acceptor);
      return;
    }
  
    // set socket options for timestamping
    grpc_tcp_set_socket_ts(tcp);
  
    grpc_handshake_manager* handshake_mgr = grpc_handshake_manager_create();
    grpc_handshake_manager_pending_list_add(&state->pending_handshake_mgrs,
                                            handshake_mgr);
    grpc_tcp_server_ref(state->tcp_server);
    gpr_mu_unlock(&state->mu);
    server_connection_state* connection_state =
        static_cast<server_connection_state*>(
            gpr_zalloc(sizeof(*connection_state)));
    gpr_ref_init(&connection_state->refs, 1);
    connection_state->svr_state = state;
    connection_state->accepting_pollset = accepting_pollset;
    connection_state->acceptor = acceptor;
    connection_state->handshake_mgr = handshake_mgr;
    connection_state->interested_parties = grpc_pollset_set_create();
    grpc_pollset_set_add_pollset(connection_state->interested_parties,
                                 connection_state->accepting_pollset);
    grpc_handshakers_add(HANDSHAKER_SERVER, state->args,
                         connection_state->interested_parties,
                         connection_state->handshake_mgr);
    const grpc_arg* timeout_arg =
        grpc_channel_args_find(state->args, GRPC_ARG_SERVER_HANDSHAKE_TIMEOUT_MS);
    connection_state->deadline =
        grpc_core::ExecCtx::Get()->Now() +
        grpc_channel_arg_get_integer(timeout_arg,
                                     {120 * GPR_MS_PER_SEC, 1, INT_MAX});
    grpc_handshake_manager_do_handshake(connection_state->handshake_mgr, tcp,
                                        state->args, connection_state->deadline,
                                        acceptor, on_handshake_done,
                                        connection_state);
  }
  
  /* Server callback: start listening on our ports */
  static void server_start_listener(grpc_server* server, void* arg,
                                    grpc_pollset** pollsets,
                                    size_t pollset_count) {
    server_state* state = static_cast<server_state*>(arg);
    gpr_mu_lock(&state->mu);
    state->shutdown = false;
    gpr_mu_unlock(&state->mu);
    grpc_tcp_server_start(state->tcp_server, pollsets, pollset_count, on_accept,
                          state);
  }
  
  static void tcp_server_shutdown_complete(void* arg, grpc_error* error) {
    server_state* state = static_cast<server_state*>(arg);
    /* ensure all threads have unlocked */
    gpr_mu_lock(&state->mu);
    grpc_closure* destroy_done = state->server_destroy_listener_done;
    GPR_ASSERT(state->shutdown);
    grpc_handshake_manager_pending_list_shutdown_all(
        state->pending_handshake_mgrs, GRPC_ERROR_REF(error));
    state->channelz_listen_socket.reset();
    gpr_mu_unlock(&state->mu);
    // Flush queued work before destroying handshaker factory, since that
    // may do a synchronous unref.
    grpc_core::ExecCtx::Get()->Flush();
    if (destroy_done != nullptr) {
      destroy_done->cb(destroy_done->cb_arg, GRPC_ERROR_REF(error));
      grpc_core::ExecCtx::Get()->Flush();
    }
    grpc_channel_args_destroy(state->args);
    gpr_mu_destroy(&state->mu);
    gpr_free(state);
  }
  
  /* Server callback: destroy the tcp listener (so we don't generate further
     callbacks) */
  static void server_destroy_listener(grpc_server* server, void* arg,
                                      grpc_closure* destroy_done) {
    server_state* state = static_cast<server_state*>(arg);
    gpr_mu_lock(&state->mu);
    state->shutdown = true;
    state->server_destroy_listener_done = destroy_done;
    grpc_tcp_server* tcp_server = state->tcp_server;
    gpr_mu_unlock(&state->mu);
    grpc_tcp_server_shutdown_listeners(tcp_server);
    grpc_tcp_server_unref(tcp_server);
  }
  
  grpc_error* grpc_chttp2_server_add_port(grpc_server* server, const char* addr,
                                          grpc_channel_args* args,
                                          int* port_num) {
    grpc_resolved_addresses* resolved = nullptr;
    grpc_tcp_server* tcp_server = nullptr;
    size_t i;
    size_t count = 0;
    int port_temp;
    grpc_error* err = GRPC_ERROR_NONE;
    server_state* state = nullptr;
    grpc_error** errors = nullptr;
    size_t naddrs = 0;
    const grpc_arg* arg = nullptr;
    intptr_t socket_uuid = 0;
  
    *port_num = -1;
  
    /* resolve address */
    err = grpc_blocking_resolve_address(addr, "https", &resolved);
    if (err != GRPC_ERROR_NONE) {
      goto error;
    }
    state = static_cast<server_state*>(gpr_zalloc(sizeof(*state)));
    GRPC_CLOSURE_INIT(&state->tcp_server_shutdown_complete,
                      tcp_server_shutdown_complete, state,
                      grpc_schedule_on_exec_ctx);
    err = grpc_tcp_server_create(&state->tcp_server_shutdown_complete, args,
                                 &tcp_server);
    if (err != GRPC_ERROR_NONE) {
      goto error;
    }
  
    state->server = server;
    state->tcp_server = tcp_server;
    state->args = args;
    state->shutdown = true;
    gpr_mu_init(&state->mu);
  
    naddrs = resolved->naddrs;
    errors = static_cast<grpc_error**>(gpr_malloc(sizeof(*errors) * naddrs));
    for (i = 0; i < naddrs; i++) {
      errors[i] =
          grpc_tcp_server_add_port(tcp_server, &resolved->addrs[i], &port_temp);
      if (errors[i] == GRPC_ERROR_NONE) {
        if (*port_num == -1) {
          *port_num = port_temp;
        } else {
          GPR_ASSERT(*port_num == port_temp);
        }
        count++;
      }
    }
    if (count == 0) {
      char* msg;
      gpr_asprintf(&msg, "No address added out of total %" PRIuPTR " resolved",
                   naddrs);
      err = GRPC_ERROR_CREATE_REFERENCING_FROM_COPIED_STRING(msg, errors, naddrs);
      gpr_free(msg);
      goto error;
    } else if (count != naddrs) {
      char* msg;
      gpr_asprintf(&msg,
                   "Only %" PRIuPTR " addresses added out of total %" PRIuPTR
                   " resolved",
                   count, naddrs);
      err = GRPC_ERROR_CREATE_REFERENCING_FROM_COPIED_STRING(msg, errors, naddrs);
      gpr_free(msg);
  
      const char* warning_message = grpc_error_string(err);
      gpr_log(GPR_INFO, "WARNING: %s", warning_message);
  
      /* we managed to bind some addresses: continue */
    }
    grpc_resolved_addresses_destroy(resolved);
  
    arg = grpc_channel_args_find(args, GRPC_ARG_ENABLE_CHANNELZ);
    if (grpc_channel_arg_get_bool(arg, GRPC_ENABLE_CHANNELZ_DEFAULT)) {
      state->channelz_listen_socket =
          grpc_core::MakeRefCounted<grpc_core::channelz::ListenSocketNode>(
              grpc_core::UniquePtr<char>(gpr_strdup(addr)));
      socket_uuid = state->channelz_listen_socket->uuid();
    }
  
    /* Register with the server only upon success */
    grpc_server_add_listener(server, state, server_start_listener,
                             server_destroy_listener, socket_uuid);
    goto done;
  
  /* Error path: cleanup and return */
  error:
    GPR_ASSERT(err != GRPC_ERROR_NONE);
    if (resolved) {
      grpc_resolved_addresses_destroy(resolved);
    }
    if (tcp_server) {
      grpc_tcp_server_unref(tcp_server);
    } else {
      grpc_channel_args_destroy(args);
      gpr_free(state);
    }
    *port_num = 0;
  
  done:
    if (errors != nullptr) {
      for (i = 0; i < naddrs; i++) {
        GRPC_ERROR_UNREF(errors[i]);
      }
      gpr_free(errors);
    }
    return err;
  }
  