/*
 *
 * 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.
 *
 */

#ifndef GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H
#define GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H

#include <grpc/support/port_platform.h>

#include "src/core/lib/iomgr/ev_posix.h"
#include "src/core/lib/iomgr/resolve_address.h"
#include "src/core/lib/iomgr/socket_utils_posix.h"
#include "src/core/lib/iomgr/tcp_server.h"
#include "src/core/lib/resource_quota/memory_quota.h"

/* one listening port */
typedef struct grpc_tcp_listener {
  int fd;
  grpc_fd* emfd;
  grpc_tcp_server* server;
  grpc_resolved_address addr;
  int port;
  unsigned port_index;
  unsigned fd_index;
  grpc_closure read_closure;
  grpc_closure destroyed_closure;
  struct grpc_tcp_listener* next;
  /* sibling is a linked list of all listeners for a given port. add_port and
     clone_port place all new listeners in the same sibling list. A member of
     the 'sibling' list is also a member of the 'next' list. The head of each
     sibling list has is_sibling==0, and subsequent members of sibling lists
     have is_sibling==1. is_sibling allows separate sibling lists to be
     identified while iterating through 'next'. */
  struct grpc_tcp_listener* sibling;
  int is_sibling;
} grpc_tcp_listener;

/* the overall server */
struct grpc_tcp_server {
  gpr_refcount refs;
  /* Called whenever accept() succeeds on a server port. */
  grpc_tcp_server_cb on_accept_cb = nullptr;
  void* on_accept_cb_arg = nullptr;

  gpr_mu mu;

  /* active port count: how many ports are actually still listening */
  size_t active_ports = 0;
  /* destroyed port count: how many ports are completely destroyed */
  size_t destroyed_ports = 0;

  /* is this server shutting down? */
  bool shutdown = false;
  /* have listeners been shutdown? */
  bool shutdown_listeners = false;
  /* use SO_REUSEPORT */
  bool so_reuseport = false;
  /* expand wildcard addresses to a list of all local addresses */
  bool expand_wildcard_addrs = false;

  /* linked list of server ports */
  grpc_tcp_listener* head = nullptr;
  grpc_tcp_listener* tail = nullptr;
  unsigned nports = 0;

  /* List of closures passed to shutdown_starting_add(). */
  grpc_closure_list shutdown_starting{nullptr, nullptr};

  /* shutdown callback */
  grpc_closure* shutdown_complete = nullptr;

  /* all pollsets interested in new connections. The object pointed at is not
   * owned by this struct */
  const std::vector<grpc_pollset*>* pollsets = nullptr;

  /* next pollset to assign a channel to */
  gpr_atm next_pollset_to_assign = 0;

  /* channel args for this server */
  grpc_channel_args* channel_args = nullptr;

  /* a handler for external connections, owned */
  grpc_core::TcpServerFdHandler* fd_handler = nullptr;

  /* used to create slice allocators for endpoints, owned */
  grpc_core::MemoryQuotaRefPtr memory_quota;
};

/* If successful, add a listener to \a s for \a addr, set \a dsmode for the
   socket, and return the \a listener. */
grpc_error_handle grpc_tcp_server_add_addr(grpc_tcp_server* s,
                                           const grpc_resolved_address* addr,
                                           unsigned port_index,
                                           unsigned fd_index,
                                           grpc_dualstack_mode* dsmode,
                                           grpc_tcp_listener** listener);

/* Get all addresses assigned to network interfaces on the machine and create a
   listener for each. requested_port is the port to use for every listener, or 0
   to select one random port that will be used for every listener. Set *out_port
   to the port selected. Return GRPC_ERROR_NONE only if all listeners were
   added. */
grpc_error_handle grpc_tcp_server_add_all_local_addrs(grpc_tcp_server* s,
                                                      unsigned port_index,
                                                      int requested_port,
                                                      int* out_port);

/* Prepare a recently-created socket for listening. */
grpc_error_handle grpc_tcp_server_prepare_socket(
    grpc_tcp_server*, int fd, const grpc_resolved_address* addr,
    bool so_reuseport, int* port);
/* Ruturn true if the platform supports ifaddrs */
bool grpc_tcp_server_have_ifaddrs(void);

#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H */
