frame_relay.h

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/* (C) 2020 Harald Welte <laforge@gnumonks.org>
 * (C) 2020 sysmocom - s.f.m.c. GmbH
 * Author: Alexander Couzens <lynxis@fe80.eu>
 *
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * This program 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.
 *
 * This program 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, see <http://www.gnu.org/licenses/>.
 *
 */
 
#pragma once
 
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/utils.h>
 
#include <stdint.h>
 
struct osmo_tdef;
struct msgb;
struct vty;
 
enum osmo_fr_role {
        FR_ROLE_USER_EQUIPMENT,
        FR_ROLE_NETWORK_EQUIPMENT,
};
 
/* 48.016 § 6.1.4.2 default maximum information field size of 1600 octets */
#define FRAME_RELAY_MTU 1600
/* FR DLC header is 2 byte */
#define FRAME_RELAY_SDU (FRAME_RELAY_MTU - 2)
 
extern const struct value_string osmo_fr_role_names[];
 
static inline const char *osmo_fr_role_str(enum osmo_fr_role role) {
        return get_value_string(osmo_fr_role_names, role);
}
 
struct osmo_fr_network {
        struct llist_head links;
 
        unsigned int n391;              /* full status polling counter */
        unsigned int n392;              /* error threshold */
        unsigned int n393;              /* monitored events count */
 
        struct osmo_tdef *T_defs;       /* T391, T392 */
};
 
struct osmo_fr_dlc;
 
/* Frame Relay Link */
struct osmo_fr_link {
        /* list in osmo_fr_network.links */
        struct llist_head list;
        struct osmo_fr_network *net;
        enum osmo_fr_role role;
        /* human-readable name */
        const char *name;
 
        /* value of the last received send sequence number field in the
         * link integrity verification information element */
        uint8_t last_rx_seq;
 
        /* value of the send sequence number field of the last link
         * integrity verification information element sent */
        uint8_t last_tx_seq;
 
        struct osmo_timer_list t391;
        struct osmo_timer_list t392;
 
        unsigned int polling_count;
        unsigned int err_count;
        unsigned int succeed;
        /* the type of the last status enquiry */
        uint8_t expected_rep;
        bool state;
 
        /* list of data link connections at this link */
        struct llist_head dlc_list;
 
        /* optional call-back to be called for each PDU received on an unknown DLC */
        int (*unknown_dlc_rx_cb)(void *cb_data, struct msgb *msg);
        void *unknown_dlc_rx_cb_data;
 
        /* call-back to be called for transmitting on the underlying hardware */
        int (*tx_cb)(void *data, struct msgb *msg);
        /* optional call-back to be called each time the status changes active/inactive */
        void (*status_cb)(struct osmo_fr_link *link, void *cb_data, bool active);
        void *cb_data;
};
 
/* Frame Relay Data Link Connection */
struct osmo_fr_dlc {
        /* entry in fr_link.dlc_list */
        struct llist_head list;
        struct osmo_fr_link *link;
 
        uint16_t dlci;
 
        /* is this DLC marked active for traffic? */
        bool active;
        /* was this DLC newly added? */
        bool add;
        /* is this DLC about to be destroyed */
        bool del;
 
        /* The local state needs to be transferred to the USER;
         * NET must wait until USER confirms it implicitly by a seq number check */
        bool state_send;
 
        /* call-back to be called for each PDU received on this DLC */
        int (*rx_cb)(void *cb_data, struct msgb *msg);
        /* optional call-back to be called each time the status changes active/inactive */
        void (*status_cb)(struct osmo_fr_dlc *dlc, void *cb_data, bool active);
        void *cb_data;
};
 
/* allocate a frame relay network */
struct osmo_fr_network *osmo_fr_network_alloc(void *ctx);
void osmo_fr_network_free(struct osmo_fr_network *net);
void osmo_fr_network_dump_vty(struct vty *vty, const struct osmo_fr_network *net);
 
/* allocate a frame relay link in a given network */
struct osmo_fr_link *osmo_fr_link_alloc(struct osmo_fr_network *net, enum osmo_fr_role role, const char *name);
 
/* free a frame link in a given network */
void osmo_fr_link_free(struct osmo_fr_link *link);
 
/* allocate a data link connectoin on a given framerelay link */
struct osmo_fr_dlc *osmo_fr_dlc_alloc(struct osmo_fr_link *link, uint16_t dlci);
void osmo_fr_dlc_free(struct osmo_fr_dlc *dlc);
 
struct osmo_fr_dlc *osmo_fr_dlc_by_dlci(struct osmo_fr_link *link, uint16_t dlci);
 
int osmo_fr_rx(struct msgb *msg);
int osmo_fr_tx_dlc(struct msgb *msg);