/** @file
 *  @brief Internal APIs for Bluetooth RFCOMM handling.
 */

/*
 * Copyright (c) 2015-2016 Intel Corporation
 *
 * 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.
 */

#include <bluetooth/rfcomm.h>

/* RFCOMM signalling connection specific context */
struct bt_rfcomm_session {
	/* L2CAP channel this context is associated with */
	struct bt_l2cap_br_chan br_chan;
	struct bt_rfcomm_dlc *dlcs;
	uint16_t mtu;
	uint8_t state;
	bool initiator;
};

enum {
	BT_RFCOMM_STATE_IDLE,
	BT_RFCOMM_STATE_INIT,
	BT_RFCOMM_STATE_CONNECTED,
	BT_RFCOMM_STATE_CONFIG,
};

struct bt_rfcomm_hdr {
	uint8_t address;
	uint8_t control;
	uint8_t length;
} __packed;

#define BT_RFCOMM_SABM	0x2f
#define BT_RFCOMM_UA	0x63
#define BT_RFCOMM_UIH	0xef

struct bt_rfcomm_msg_hdr {
	uint8_t type;
	uint8_t len;
} __packed;

#define BT_RFCOMM_PN	0x20
struct bt_rfcomm_pn {
	uint8_t  dlci;
	uint8_t  flow_ctrl;
	uint8_t  priority;
	uint8_t  ack_timer;
	uint16_t mtu;
	uint8_t  max_retrans;
	uint8_t  credits;
} __packed;

#define BT_RFCOMM_SIG_MIN_MTU	23
#define BT_RFCOMM_SIG_MAX_MTU	32767

#define BT_RFCOMM_CHECK_MTU(mtu) (!!((mtu) >= BT_RFCOMM_SIG_MIN_MTU && \
				  (mtu) <= BT_RFCOMM_SIG_MAX_MTU))

/* Helper to calculate needed outgoing buffer size */
#define BT_RFCOMM_BUF_SIZE(mtu) (CONFIG_BLUETOOTH_HCI_SEND_RESERVE + \
				sizeof(struct bt_hci_acl_hdr) + \
				sizeof(struct bt_l2cap_hdr) + \
				sizeof(struct bt_rfcomm_hdr) + (mtu))

#define BT_RFCOMM_GET_DLCI(addr)	(((addr) & 0xfc) >> 2)
#define BT_RFCOMM_GET_FRAME_TYPE(ctrl)	((ctrl) & 0xef)
#define BT_RFCOMM_GET_MSG_TYPE(type)	(((type) & 0xfc) >> 2)
#define BT_RFCOMM_GET_MSG_CR(type)	(((type) & 0x02) >> 1)
#define	BT_RFCOMM_GET_LEN(len)		(((len) & 0xfe) >> 1)
#define BT_RFCOMM_GET_CHANNEL(dlci)	((dlci) >> 1)

#define BT_RFCOMM_SET_ADDR(dlci, cr) ((((dlci) & 0x3f) << 2) | \
				      ((cr) << 1) | 0x01)
#define BT_RFCOMM_SET_CTRL(type, pf)	(((type) & 0xef) | ((pf) << 4))
#define BT_RFCOMM_SET_LEN_8(len)	(((len) << 1) | 1)
#define BT_RFCOMM_SET_MSG_TYPE(type, cr) (((type) << 2) | (cr << 1) | 0x01)

#define BT_RFCOMM_LEN_EXTENDED(len)	(!((len) & 0x01))

#define BT_RFCOMM_MSG_CMD	1
#define BT_RFCOMM_MSG_RESP	0

/* Length can be 2 bytes depending on data size */
#define BT_RFCOMM_HDR_SIZE	(sizeof(struct bt_rfcomm_hdr) + 1)
#define BT_RFCOMM_FCS_SIZE	1

#define BT_RFCOMM_FCS_LEN_UIH		2
#define BT_RFCOMM_FCS_LEN_NON_UIH	3

/* Initialize RFCOMM signal layer */
void bt_rfcomm_init(void);