/*

 * Copyright (C) 2013-2014 OpenSIPS Solutions

 * Copyright (C) 2001-2003 FhG Fokus

 *

 * This file is part of opensips, a free SIP server.

 *

 * opensips is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version

 *

 * opensips is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA

 *

 * History:

 * --------

 * 2015-02-05 imported from former tpc_read.c (bogdan)

 */

#include <stdint.h>

#include <sys/socket.h>

#include "../pt_load.h"

#include "../ipc.h"

#include "../timer.h"

#include "../reactor.h"

#include "../async.h"

#include "../cfg_reload.h"

#include "../mem/shm_mem.h"

#include "../receive.h"

#include "../profiling.h"

#include "tcp_conn.h"

#include "net_tcp.h"

#include "trans.h"

#include "net_tcp_dbg.h"

/*!< the FD currently used by the process to communicate with TCP MAIN*/

static int _my_fd_to_tcp_main = -1;

static int tcpmain_sock=-1;

/* wrapper around internal tcpconn_release() - to be called by functions which

 * used tcp_conn_get(), in order to release the connection;

 * It does the unref and pushes back (if needed) some update to TCP main;

 * right now, it used only from the xxx_send() functions

 */

void tcp_conn_release(struct tcp_connection* c, int pending_data)

{

  if (c->state==S_CONN_BAD) {

    /* do more or less nothing, let the TCP READER owning the conn

     * to trash it based on the S_CONN_BAD marker */

    c->lifetime=0;

    c->timeout=0;

    /* but be sure we unref the conn */

    tcpconn_put(c);

    return;

  }

  if (!pending_data && c->async && c->async->pending &&

      ((c->state == S_CONN_OK && (c->flags & F_CONN_REMOVED_WRITE)) ||

       c->fd == -1))

    pending_data = 1;

  if (pending_data) {

    if (tcp_async_write_job(c) < 0) {

      LM_ERR("failed to queue direct TCP write job for conn %p / %u\n",

        c, c->id);

      tcpconn_put(c);

    }

    return;

  }

  tcpconn_put(c);

}

struct tcp_ipc_payload {

  struct receive_info rcv;

  struct tcp_connection *conn;

  int msg_len;

  int data_len;

  char msg_buf[0];

};

/*! \brief

 *  handle io routine, based on the fd_map type

 * (it will be called from reactor_main_loop )

 * params:  fm  - pointer to a fd hash entry

 *          idx - index in the fd_array (or -1 if not known)

 * return: -1 on error, or when we are not interested any more on reads

 *            from this fd (e.g.: we are closing it )

 *          0 on EAGAIN or when by some other way it is known that no more

 *            io events are queued on the fd (the receive buffer is empty).

 *            Usefull to detect when there are no more io events queued for

 *            sigio_rt, epoll_et, kqueue.

 *         >0 on successful read from the fd (when there might be more io

 *            queued -- the receive buffer might still be non-empty)

 */

inline static int handle_io(struct fd_map* fm, int idx,int event_type)

{

  int ret=0;

  int n=0;

  (void)idx;

  pt_become_active();

  pre_run_handle_script_reload(fm->app_flags);

  profiling_proc_start( LEVEL_SIP, 1);

  switch(fm->type){

    case F_TIMER_JOB:

      profiling_proc_enter( LEVEL_FULL, "timer_job", 1 );

      handle_timer_job();

      profiling_proc_exit( LEVEL_FULL, "timer_job", n);

      break;

    case F_SCRIPT_ASYNC:

      profiling_proc_enter( LEVEL_SIP, "async_script", 0 );

      n = async_script_resume_f( fm->fd, fm->data,

        (event_type==IO_WATCH_TIMEOUT)?1:0 );

      profiling_proc_exit( LEVEL_SIP, "async_script", n);

      break;

    case F_FD_ASYNC:

      profiling_proc_enter( LEVEL_SIP, "async_fd", 0 );

      n = async_fd_resume( fm->fd, fm->data);

      profiling_proc_exit( LEVEL_SIP, "async_fd", n);

      break;

    case F_LAUNCH_ASYNC:

      profiling_proc_enter( LEVEL_SIP, "async_launch", 0 );

      n = async_launch_resume( fm->fd, fm->data);

      profiling_proc_exit( LEVEL_SIP, "async_launch", n);

      break;

    case F_IPC:

      profiling_proc_enter( LEVEL_SIP, "ipc_job", 1 );

      ipc_handle_job(fm->fd);

      profiling_proc_exit( LEVEL_SIP, "ipc_job", n );

      break;

    case F_TCPMAIN:

    {

      struct tcp_ipc_payload *payload;

      uintptr_t payload_ptr;

again_payload:

      ret = n = recv(fm->fd, &payload_ptr, sizeof(payload_ptr),

        MSG_DONTWAIT);

      if (n < 0) {

        if (errno == EWOULDBLOCK || errno == EAGAIN) {

          ret = 0;

          break;

        } else if (errno == EINTR) {

          goto again_payload;

        }

        LM_CRIT("read from tcp main dispatch socket failed: %s\n",

          strerror(errno));

        goto error;

      }

      if (n == 0) {

        LM_WARN("EOF received from tcp main dispatch socket\n");

        goto error;

      }

      if (n != (int)sizeof(payload_ptr)) {

        LM_CRIT("short read on tcp main dispatch socket: %d bytes\n", n);

        goto error;

      }

      payload = (struct tcp_ipc_payload *)(uintptr_t)payload_ptr;

      if (!payload) {

        LM_BUG("null payload pointer from tcp main\n");

        break;

      }

      profiling_proc_enter( LEVEL_SIP,

        ss_merge256( protos[payload->rcv.proto].name,

        " proto handling"), 0);

      bind_address = payload->rcv.bind_address;

      if (payload->rcv.proto > PROTO_NONE &&

          payload->rcv.proto < PROTO_LAST &&

          is_tcp_based_proto(payload->rcv.proto) &&

          protos[payload->rcv.proto].net.stream.handle) {

        if ( (n=protos[payload->rcv.proto].net.stream.handle(

            payload->msg_buf, payload->msg_len, &payload->rcv,

            payload->data_len ?

            payload->msg_buf + payload->msg_len + 1 : NULL,

            payload->data_len)) < 0)

          LM_ERR("TCP dispatch handler failed\n");

      } else if ( (n=receive_msg(payload->msg_buf, payload->msg_len,

          &payload->rcv, NULL, 0)) < 0) {

        LM_ERR("receive_msg() failed for dispatched TCP message\n");

      }

      profiling_proc_exit( LEVEL_SIP, "handling done", n);

      if (payload->conn)

        tcpconn_put(payload->conn);

      shm_free(payload);

      break;

    }

    case F_NONE:

      LM_CRIT("empty fd map %p: "

            "{%d, %d, %p}\n", fm,

            fm->fd, fm->type, fm->data);

      goto error;

    default:

      LM_CRIT("unknown fd type %d\n", fm->type);

      goto error;

  }

  if (_termination_in_progress==1) {

    /* check if anything is still left */

    if (reactor_is_empty()) {

      LM_WARN("reactor got empty while termination in progress\n");

      ipc_handle_all_pending_jobs(IPC_FD_READ_SELF);

      if (reactor_is_empty())

        dynamic_process_final_exit();

    }

  }

  profiling_proc_end( LEVEL_SIP, 0 );

  post_run_handle_script_reload();

  pt_become_idle();

  return ret;

error:

  profiling_proc_end( LEVEL_SIP, -1 );

  pt_become_idle();

  return -1;

}

int tcp_worker_proc_reactor_init( int unix_sock)

{

  /* init reactor for TCP worker */

  tcpmain_sock=unix_sock; /* init com. socket */

  if ( init_worker_reactor( "TCP_worker", RCT_PRIO_MAX)<0 ) {

    goto error;

  }

  /* start watching for the timer jobs */

  if (reactor_add_reader( timer_fd_out, F_TIMER_JOB, RCT_PRIO_TIMER,NULL)<0){

    LM_CRIT("failed to add timer pipe_out to reactor\n");

    goto error;

  }

  /* init: start watching for the IPC jobs */

  if (reactor_add_reader(IPC_FD_READ_SELF, F_IPC, RCT_PRIO_ASYNC, NULL)<0){

    LM_CRIT("failed to add IPC pipe to reactor\n");

    goto error;

  }

  /* init: start watching for IPC "dispatched" jobs */

  if (reactor_add_reader(IPC_FD_READ_SHARED, F_IPC, RCT_PRIO_ASYNC, NULL)<0){

    LM_CRIT("failed to add IPC shared pipe to reactor\n");

    return -1;

  }

  /* add the unix socket */

  if (reactor_add_reader( tcpmain_sock, F_TCPMAIN, RCT_PRIO_PROC, NULL)<0) {

    LM_CRIT("failed to add socket to the fd list\n");

    goto error;

  }

  _my_fd_to_tcp_main = tcpmain_sock;

  return 0;

error:

  destroy_worker_reactor();

  return -1;

}

void tcp_worker_proc_loop(void)

{

  /* main loop */

  reactor_main_loop(TCP_CHILD_SELECT_TIMEOUT, error,);

  LM_CRIT("exiting...");

  exit(-1);

error:

  destroy_worker_reactor();

}

void tcp_terminate_worker(void)

{

  /*remove from reactor all the shared fds, so we stop reading from them */

  /*remove timer jobs pipe */

  reactor_del_reader( timer_fd_out, -1, 0);

  /*remove IPC dispatcher pipe */

  reactor_del_reader( IPC_FD_READ_SHARED, -1, 0);

  /*remove private IPC pipe */

  reactor_del_reader( IPC_FD_READ_SELF, -1, 0);

  /*remove unix sock to TCP main */

  reactor_del_reader( _my_fd_to_tcp_main, -1, 0);

  _termination_in_progress = 1;

  /* let's drain the private IPC */

  ipc_handle_all_pending_jobs(IPC_FD_READ_SELF);

  /* what is left now is the reactor are async fd's, so we need to 

   * wait to complete all of them */

  if (reactor_is_empty())

    dynamic_process_final_exit();

  /* the exit will be triggered by the reactor, when empty */

  LM_INFO("reactor not empty, waiting for pending async/conns\n");

}