/*******************************************************************************

  Eurecom OpenAirInterface
  Copyright(c) 1999 - 2012 Eurecom

  This program is free software; you can redistribute it and/or modify it
  under the terms and conditions of the GNU General Public License,
  version 2, as published by the Free Software Foundation.

  This program is distributed in the hope 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 St - Fifth Floor, Boston, MA 02110-1301 USA.

  The full GNU General Public License is included in this distribution in
  the file called "COPYING".

  Contact Information
  Openair Admin: openair_admin@eurecom.fr
  Openair Tech : openair_tech@eurecom.fr
  Forums       : http://forums.eurecom.fr/openairinterface
  Address      : EURECOM, Campus SophiaTech, 450 Route des Chappes
                 06410 Biot FRANCE

*******************************************************************************/

#include <stdint.h>

#include "queue.h"
#include "tree.h"

#include "sctp_eNB_defs.h"

#ifndef S1AP_ENB_DEFS_H_
#define S1AP_ENB_DEFS_H_

#define S1AP_ENB_NAME_LENGTH_MAX    (150)

typedef enum {
    /* Disconnected state: initial state for any association. */
    S1AP_ENB_STATE_DISCONNECTED = 0x0,
    /* State waiting for S1 Setup response message if eNB is MME accepted or
     * S1 Setup failure if MME rejects the eNB.
     */
    S1AP_ENB_STATE_WAITING     = 0x1,
    /* The eNB is successfully connected to MME, UE contexts can be created. */
    S1AP_ENB_STATE_CONNECTED   = 0x2,
    /* The MME has sent an overload start message. Once the MME disables the
     * OVERLOAD marker, the state of the association will be
     * S1AP_ENB_STATE_CONNECTED.
     */
    S1AP_ENB_OVERLOAD          = 0x3,
    /* Max number of states available */
    S1AP_ENB_STATE_MAX,
} s1ap_eNB_state_t;

/* If the Overload Action IE in the OVERLOAD START message is set to
 * - “reject all RRC connection establishments for non-emergency mobile
 *    originated data transfer “ (i.e. reject traffic corresponding to RRC cause
 *    “mo-data “ (TS 36.331 [16])), or
 * - “reject all RRC connection establishments for signalling “ (i.e. reject
 *    traffic corresponding to RRC cause “modata” and “mo-signalling”
 *    (TS 36.331 [16])),or
 * - “only permit RRC connection establishments for emergency sessions and
 *    mobile terminated services” (i.e. only permit traffic corresponding to RRC
 *    cause “emergency” and “mt-Access” (TS 36.331 [16])).
 *
 * NOTE: When the Overload Action IE is set to “only permit RRC connection
 * establishments for emergency sessions and mobile terminated services”,
 * emergency calls with RRC cause “highPriorityAcess” from high priority users
 * are rejected (TS 24.301 [24]).
 */
typedef enum {
    S1AP_OVERLOAD_REJECT_MO_DATA        = 0x0,
    S1AP_OVERLOAD_REJECT_ALL_SIGNALLING = 0x1,
    S1AP_OVERLOAD_ONLY_EMERGENCY_AND_MT = 0x2,
    S1AP_NO_OVERLOAD                    = 0x3,
    S1AP_OVERLOAD_MAX,
} s1ap_overload_state_t;

/* Served PLMN identity element */
struct plmn_identity_s {
    uint16_t mcc;
    uint16_t mnc;
    STAILQ_ENTRY(plmn_identity_s) next;
};

/* Served group id element */
struct served_group_id_s {
    uint16_t mme_group_id;
    STAILQ_ENTRY(served_group_id_s) next;
};

/* Served mme code for a particular MME */
struct mme_code_s {
    uint8_t mme_code;
    STAILQ_ENTRY(mme_code_s) next;
};

/* Served gummei element */
struct served_gummei_s {
    /* Number of MME served PLMNs */
    uint8_t nb_served_plmns;
    /* List of served PLMNs by MME */
    STAILQ_HEAD(served_plmns_s, plmn_identity_s) served_plmns;

    /* Number of group id in list */
    uint8_t nb_group_id;
    /* Served group id list */
    STAILQ_HEAD(served_group_ids_s, served_group_id_s) served_group_ids;

    /* Number of MME code */
    uint8_t nb_mme_code;
    /* MME Code to uniquely identify an MME within an MME pool area */
    STAILQ_HEAD(mme_codes_s, mme_code_s) mme_codes;

    /* Next GUMMEI element */
    STAILQ_ENTRY(served_gummei_s) next;
};

struct s1ap_eNB_instance_s;

/* This structure describes association of a eNB to a MME */
typedef struct s1ap_eNB_mme_data_s {
    /* MME descriptors tree, ordered by sctp assoc id */
    RB_ENTRY(s1ap_eNB_mme_data_s) entry;

    /* This is the optional name provided by the MME */
    char *mme_name;

    /* List of served GUMMEI per MME. There is one GUMMEI per RAT with a max
     * number of 8 RATs but in our case only one is used. The LTE related pool
     * configuration is included on the first place in the list.
     */
    STAILQ_HEAD(served_gummeis_s, served_gummei_s) served_gummei;

    /* Relative processing capacity of an MME with respect to the other MMEs
     * in the pool in order to load-balance MMEs within a pool as defined
     * in TS 23.401.
     */
    uint8_t relative_mme_capacity;

    /* Current MME overload information (if any). */
    s1ap_overload_state_t overload_state;
    /* Current eNB->MME S1AP association state */
    s1ap_eNB_state_t state;

    /* Next usable stream for UE signalling */
    int32_t nextstream;

    /* Number of input/ouput streams */
    uint16_t in_streams;
    uint16_t out_streams;

    /* Connexion id used between SCTP/S1AP */
    uint16_t cnx_id;

    /* SCTP association id */
    int32_t  assoc_id;

    /* Only meaningfull in virtual mode */
    struct s1ap_eNB_instance_s *s1ap_eNB_instance;
} s1ap_eNB_mme_data_t;

typedef struct s1ap_eNB_instance_s {
    /* Next s1ap eNB association.
     * Only used for virtual mode.
     */
    STAILQ_ENTRY(s1ap_eNB_instance_s) s1ap_eNB_entries;

    /* Tree of S1AP MME associations ordered by association ID */
    RB_HEAD(s1ap_mme_map, s1ap_eNB_mme_data_s) s1ap_mme_head;

    /* TODO: add a map ordered by relative MME capacity */

    /* Tree of UE ordered by eNB_ue_s1ap_id's */
    RB_HEAD(s1ap_ue_map, s1ap_eNB_ue_context_s) s1ap_ue_head;

    /* For virtual mode, mod_id as defined in the rest of the L1/L2 stack */
    instance_t instance;

    /* Displayable name of eNB */
    char *eNB_name;

    /* Unique eNB_id to identify the eNB within EPC.
     * In our case the eNB is a macro eNB so the id will be 20 bits long.
     * For Home eNB id, this field should be 28 bits long.
     */
    uint32_t eNB_id;
    /* The type of the cell */
    enum cell_type_e cell_type;

    /* Tracking area code */
    uint16_t tac;

    /* Mobile Country Code
     * Mobile Network Code
     */
    uint16_t  mcc;
    uint16_t  mnc;

    /* Default Paging DRX of the eNB as defined in TS 36.304 */
    paging_drx_t default_drx;
} s1ap_eNB_instance_t;

typedef struct {
    /* List of served eNBs
     * Only used for virtual mode
     */
    STAILQ_HEAD(s1ap_eNB_instances_head_s, s1ap_eNB_instance_s) s1ap_eNB_instances_head;
    /* Nb of registered eNBs */
    uint8_t nb_registered_eNBs;

    /* Generate a unique connexion id used between S1AP and SCTP */
    uint16_t global_cnx_id;
} s1ap_eNB_internal_data_t;

inline int s1ap_eNB_compare_assoc_id(
    struct s1ap_eNB_mme_data_s *p1, struct s1ap_eNB_mme_data_s *p2);

/* Generate the tree management functions */
RB_PROTOTYPE(s1ap_mme_map, s1ap_eNB_mme_data_s, entry,
             s1ap_eNB_compare_assoc_id);

int s1ap_eNB_init(s1ap_eNB_instance_t *eNB_desc_p,
                  char *local_ip_addr[],  int nb_local_ip,
                  char *remote_ip_addr[], int nb_remote_ip);

#endif /* S1AP_ENB_DEFS_H_ */
