/*******************************************************************************
    OpenAirInterface
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface 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 3 of the License, or
    (at your option) any later version.


    OpenAirInterface 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 OpenAirInterface.The full GNU General Public License is
   included in this distribution in the file called "COPYING". If not,
   see <http://www.gnu.org/licenses/>.

  Contact Information
  OpenAirInterface Admin: openair_admin@eurecom.fr
  OpenAirInterface Tech : openair_tech@eurecom.fr
  OpenAirInterface Dev  : openair4g-devel@eurecom.fr

  Address      : Eurecom, Compus SophiaTech 450, route des chappes, 06451 Biot, France.

 *******************************************************************************/
/*! \file udp_eNB_task.c
* \brief
* \author Sebastien ROUX, Lionel Gauthier
* \company Eurecom
* \email: lionel.gauthier@eurecom.fr
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <pthread.h>

#include "queue.h"
#include "intertask_interface.h"
#include "assertions.h"
#include "udp_eNB_task.h"

#include "UTIL/LOG/log.h"
#include "UTIL/LOG/vcd_signal_dumper.h"


#define IPV4_ADDR    "%u.%u.%u.%u"
#define IPV4_ADDR_FORMAT(aDDRESS)               \
    (uint8_t)((aDDRESS)  & 0x000000ff),         \
    (uint8_t)(((aDDRESS) & 0x0000ff00) >> 8 ),  \
    (uint8_t)(((aDDRESS) & 0x00ff0000) >> 16),  \
    (uint8_t)(((aDDRESS) & 0xff000000) >> 24)


struct udp_socket_desc_s {
    int       sd;              /* Socket descriptor to use */

    pthread_t listener_thread; /* Thread affected to recv */

    char     *local_address;   /* Local ipv4 address to use */
    uint16_t  local_port;      /* Local port to use */

    task_id_t task_id;         /* Task who has requested the new endpoint */

    STAILQ_ENTRY(udp_socket_desc_s) entries;
};

static STAILQ_HEAD(udp_socket_list_s, udp_socket_desc_s) udp_socket_list;
static pthread_mutex_t udp_socket_list_mutex = PTHREAD_MUTEX_INITIALIZER;


static
struct udp_socket_desc_s *
udp_eNB_get_socket_desc(task_id_t task_id);

void udp_eNB_process_file_descriptors(
        struct epoll_event *events,
        int nb_events);

static
int
udp_eNB_create_socket(
        int port,
        char *ip_addr,
        task_id_t task_id);

int
udp_eNB_send_to(
    int sd,
    uint16_t port,
    uint32_t address,
    const uint8_t *buffer,
    uint32_t length);

void udp_eNB_receiver(struct udp_socket_desc_s *udp_sock_pP);

void *udp_eNB_task(void *args_p);

int udp_enb_init(const Enb_properties_t *enb_config_p);
/* @brief Retrieve the descriptor associated with the task_id
 */
static
struct udp_socket_desc_s *udp_eNB_get_socket_desc(task_id_t task_id)
{
    struct udp_socket_desc_s *udp_sock_p = NULL;

#if defined(LOG_UDP) && LOG_UDP > 0
    LOG_T(UDP_, "Looking for task %d\n", task_id);
#endif

    STAILQ_FOREACH(udp_sock_p, &udp_socket_list, entries) {
        if (udp_sock_p->task_id == task_id) {
#if defined(LOG_UDP) && LOG_UDP > 0
            LOG_T(UDP_, "Found matching task desc\n");
#endif
            break;
        }
    }
    return udp_sock_p;
}

void udp_eNB_process_file_descriptors(struct epoll_event *events, int nb_events)
{
    int                       i;
    struct udp_socket_desc_s *udp_sock_p = NULL;

    if (events == NULL) {
        return;
    }

    for (i = 0; i < nb_events; i++) {
        STAILQ_FOREACH(udp_sock_p, &udp_socket_list, entries) {
            if (udp_sock_p->sd == events[i].data.fd) {
#if defined(LOG_UDP) && LOG_UDP > 0
                LOG_D(UDP_, "Found matching task desc\n");
#endif
                udp_eNB_receiver(udp_sock_p);
                break;
            }
        }
    }
}

static
int udp_eNB_create_socket(int port, char *ip_addr, task_id_t task_id)
{

    struct udp_socket_desc_s  *udp_socket_desc_p = NULL;
    int                       sd, rc;
    struct sockaddr_in        sin;

    LOG_I(UDP_, "Initializing UDP for local address %s with port %d\n", ip_addr, port);

    sd = socket(AF_INET, SOCK_DGRAM, 0);
    AssertFatal(sd > 0, "UDP: Failed to create new socket: (%s:%d)\n", strerror(errno), errno);

    memset(&sin, 0, sizeof(struct sockaddr_in));
    sin.sin_family      = AF_INET;
    sin.sin_port        = htons(port);
    if (ip_addr == NULL) {
        sin.sin_addr.s_addr = INADDR_ANY;
    } else {
        sin.sin_addr.s_addr = inet_addr(ip_addr);
    }

    if ((rc = bind(sd, (struct sockaddr *)&sin, sizeof(struct sockaddr_in))) < 0) {
        close(sd);
        AssertFatal(rc >= 0, "UDP: Failed to bind socket: (%s:%d)\n\n", strerror(errno), errno);
    }

    /* Create a new descriptor for this connection */
    udp_socket_desc_p = calloc(1, sizeof(struct udp_socket_desc_s));

    DevAssert(udp_socket_desc_p != NULL);

    udp_socket_desc_p->sd            = sd;
    udp_socket_desc_p->local_address = ip_addr;
    udp_socket_desc_p->local_port    = port;
    udp_socket_desc_p->task_id       = task_id;

    LOG_I(UDP_, "Inserting new descriptor for task %d, sd %d\n", udp_socket_desc_p->task_id, udp_socket_desc_p->sd);
    pthread_mutex_lock(&udp_socket_list_mutex);
    STAILQ_INSERT_TAIL(&udp_socket_list, udp_socket_desc_p, entries);
    pthread_mutex_unlock(&udp_socket_list_mutex);

    itti_subscribe_event_fd(TASK_UDP, sd);
    LOG_I(UDP_, "Initializing UDP for local address %s with port %d: DONE\n", ip_addr, port);
    return sd;
}

int
udp_eNB_send_to(
    int sd,
    uint16_t port,
    uint32_t address,
    const uint8_t *buffer,
    uint32_t length)
{
    struct sockaddr_in to;
    socklen_t          to_length;

    if (sd <= 0 || ((buffer == NULL) && (length > 0))) {
        LOG_E(UDP_, "udp_send_to: bad param\n");
        return -1;
    }

    memset(&to, 0, sizeof(struct sockaddr_in));
    to_length = sizeof(to);

    to.sin_family      = AF_INET;
    to.sin_port        = htons(port);
    to.sin_addr.s_addr = address;

    if (sendto(sd, (void *)buffer, (size_t)length, 0, (struct sockaddr *)&to,
               to_length) < 0) {
        LOG_E(UDP_,
              "[SD %d] Failed to send data to "IPV4_ADDR" on port %d, buffer size %u\n",
              sd, IPV4_ADDR_FORMAT(address), port, length);
        return -1;
    }
#if defined(LOG_UDP) && LOG_UDP > 0
    LOG_I(UDP_, "[SD %d] Successfully sent to "IPV4_ADDR
          " on port %d, buffer size %u, buffer address %x\n",
          sd, IPV4_ADDR_FORMAT(address), port, length, buffer);
#endif
    return 0;
}


void udp_eNB_receiver(struct udp_socket_desc_s *udp_sock_pP)
{
    uint8_t                   l_buffer[2048];
    int                n;
    socklen_t          from_len;
    struct sockaddr_in addr;
    MessageDef               *message_p        = NULL;
    udp_data_ind_t           *udp_data_ind_p   = NULL;
    uint8_t                  *forwarded_buffer = NULL;

    if (1) {
        from_len = (socklen_t)sizeof(struct sockaddr_in);

        if ((n = recvfrom(udp_sock_pP->sd, l_buffer, sizeof(l_buffer), 0,
                          (struct sockaddr *)&addr, &from_len)) < 0) {
            LOG_E(UDP_, "Recvfrom failed %s\n", strerror(errno));
            return;
        } else if (n == 0){
            LOG_W(UDP_, "Recvfrom returned 0\n");
        	return;
        } else{
            forwarded_buffer = itti_malloc(TASK_UDP, udp_sock_pP->task_id, n*sizeof(uint8_t));
            DevAssert(forwarded_buffer != NULL);
            memcpy(forwarded_buffer, l_buffer, n);
            message_p = itti_alloc_new_message(TASK_UDP, UDP_DATA_IND);
            DevAssert(message_p != NULL);
            udp_data_ind_p = &message_p->ittiMsg.udp_data_ind;
            udp_data_ind_p->buffer        = forwarded_buffer;
            udp_data_ind_p->buffer_length = n;
            udp_data_ind_p->peer_port     = htons(addr.sin_port);
            udp_data_ind_p->peer_address  = addr.sin_addr.s_addr;

#if defined(LOG_UDP) && LOG_UDP > 0
            LOG_I(UDP_, "Msg of length %d received from %s:%u\n",
                      n, inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
#endif
            if (itti_send_msg_to_task(udp_sock_pP->task_id, INSTANCE_DEFAULT, message_p) < 0) {
                LOG_I(UDP_, "Failed to send message %d to task %d\n",
                          UDP_DATA_IND,
                          udp_sock_pP->task_id);
                return;
            }
        }
    }
    //close(udp_sock_p->sd);
    //udp_sock_p->sd = -1;

    //pthread_mutex_lock(&udp_socket_list_mutex);
    //STAILQ_REMOVE(&udp_socket_list, udp_sock_p, udp_socket_desc_s, entries);
    //pthread_mutex_unlock(&udp_socket_list_mutex);
}


void *udp_eNB_task(void *args_p)
{
    int                 nb_events;
    struct epoll_event *events;
    MessageDef         *received_message_p    = NULL;
    const char         *msg_name = NULL;
    instance_t          instance  = 0;
    udp_enb_init(NULL);

    itti_mark_task_ready(TASK_UDP);
    while(1) {
        itti_receive_msg(TASK_UDP, &received_message_p);
        vcd_signal_dumper_dump_function_by_name(VCD_SIGNAL_DUMPER_FUNCTIONS_UDP_ENB_TASK, VCD_FUNCTION_IN);
#if defined(LOG_UDP) && LOG_UDP > 0
        LOG_D(UDP_, "Got message %p\n", &received_message_p);
#endif
        if (received_message_p != NULL) {

            msg_name = ITTI_MSG_NAME (received_message_p);
            instance = ITTI_MSG_INSTANCE (received_message_p);

            switch (ITTI_MSG_ID(received_message_p))
            {
                case UDP_INIT: {
                    LOG_D(UDP_, "Received UDP_INIT\n");
                    udp_init_t *udp_init_p;
                    udp_init_p = &received_message_p->ittiMsg.udp_init;
                    udp_eNB_create_socket(
                    udp_init_p->port,
                    udp_init_p->address,
                    ITTI_MSG_ORIGIN_ID(received_message_p));
                } break;

                case UDP_DATA_REQ: {
#if defined(LOG_UDP) && LOG_UDP > 0
                    LOG_D(UDP_, "Received UDP_DATA_REQ\n");
#endif
                    int     udp_sd = -1;
                    ssize_t bytes_written;

                    struct udp_socket_desc_s *udp_sock_p = NULL;
                    udp_data_req_t           *udp_data_req_p;
                    struct sockaddr_in        peer_addr;

                    udp_data_req_p = &received_message_p->ittiMsg.udp_data_req;

                    memset(&peer_addr, 0, sizeof(struct sockaddr_in));

                    peer_addr.sin_family       = AF_INET;
                    peer_addr.sin_port         = htons(udp_data_req_p->peer_port);
                    peer_addr.sin_addr.s_addr  = udp_data_req_p->peer_address;

                    pthread_mutex_lock(&udp_socket_list_mutex);
                    udp_sock_p = udp_eNB_get_socket_desc(ITTI_MSG_ORIGIN_ID(received_message_p));

                    if (udp_sock_p == NULL) {
                        LOG_E(UDP_,
                                "Failed to retrieve the udp socket descriptor "
                                "associated with task %d\n",
                                ITTI_MSG_ORIGIN_ID(received_message_p));
                        pthread_mutex_unlock(&udp_socket_list_mutex);
                        if (udp_data_req_p->buffer) {
                            itti_free(ITTI_MSG_ORIGIN_ID(received_message_p), udp_data_req_p->buffer);
                        }
                        goto on_error;
                    }
                    udp_sd = udp_sock_p->sd;
                    pthread_mutex_unlock(&udp_socket_list_mutex);

#if defined(LOG_UDP) && LOG_UDP > 0
                    LOG_D(UDP_, "[%d] Sending message of size %u to "IPV4_ADDR" and port %u\n",
                            udp_sd,
                            udp_data_req_p->buffer_length,
                          IPV4_ADDR_FORMAT(udp_data_req_p->peer_address),
                          udp_data_req_p->peer_port);
#endif
                    bytes_written = sendto(
                        udp_sd,
                        &udp_data_req_p->buffer[udp_data_req_p->buffer_offset],
                        udp_data_req_p->buffer_length,
                        0,
                        (struct sockaddr *)&peer_addr,
                        sizeof(struct sockaddr_in));

                    if (bytes_written != udp_data_req_p->buffer_length) {
                        LOG_E(UDP_, "There was an error while writing to socket %u rc %d"
                            "(%d:%s) May be normal if GTPU kernel module loaded on same host (may NF_DROP IP packet)\n",
                            udp_sd, bytes_written, errno, strerror(errno));
                    }

                    itti_free(ITTI_MSG_ORIGIN_ID(received_message_p), udp_data_req_p->buffer);
                } break;

                case TERMINATE_MESSAGE: {
                    LOG_W(UDP_, "Received TERMINATE_MESSAGE\n");
                    itti_exit_task();
                } break;

                case MESSAGE_TEST: {
                } break;

                default: {
                	LOG_W(UDP_, "Unkwnon message ID %d:%s\n",
                            ITTI_MSG_ID(received_message_p),
                            ITTI_MSG_NAME(received_message_p));
                } break;
            }
on_error:
            itti_free (ITTI_MSG_ORIGIN_ID(received_message_p), received_message_p);
            received_message_p = NULL;
        }
        nb_events = itti_get_events(TASK_UDP, &events);
        /* Now handle notifications for other sockets */
        if (nb_events > 0) {
#if defined(LOG_UDP) && LOG_UDP > 0
            LOG_D(UDP_, "UDP task Process %d events\n",nb_events);
#endif
            udp_eNB_process_file_descriptors(events, nb_events);
        }
        vcd_signal_dumper_dump_function_by_name(VCD_SIGNAL_DUMPER_FUNCTIONS_UDP_ENB_TASK, VCD_FUNCTION_OUT);
    }
    LOG_N(UDP_, "Task UDP eNB exiting\n");
    return NULL;
}

int udp_enb_init(const Enb_properties_t *enb_config_p)
{
    LOG_I(UDP_, "Initializing UDP task interface\n");
    STAILQ_INIT(&udp_socket_list);
    LOG_I(UDP_, "Initializing UDP task interface: DONE\n");
    return 0;
}