esp-idf/components/bt/bluedroid/stack/rfcomm/rfc_port_fsm.c

/******************************************************************************
 *
 *  Copyright (C) 1999-2012 Broadcom 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.
 *
 ******************************************************************************/

/******************************************************************************
 *
 *  This file contains state machine and action routines for a port of the
 *  RFCOMM unit
 *
 ******************************************************************************/
#include <string.h>
#include "bt_target.h"
#include "gki.h"
#include "rfcdefs.h"
#include "btm_api.h"
#include "btm_int.h"
#include "port_api.h"
#include "port_int.h"
#include "rfc_int.h"
#include "bt_defs.h"

/********************************************************************************/
/*              L O C A L    F U N C T I O N     P R O T O T Y P E S            */
/********************************************************************************/
static void rfc_port_sm_state_closed (tPORT *p_port, UINT16 event, void *p_data);
static void rfc_port_sm_sabme_wait_ua (tPORT *p_port, UINT16 event, void *p_data);
static void rfc_port_sm_opened (tPORT *p_port, UINT16 event, void *p_data);
static void rfc_port_sm_orig_wait_sec_check (tPORT *p_port, UINT16 event, void *p_data);
static void rfc_port_sm_term_wait_sec_check (tPORT *p_port, UINT16 event, void *p_data);
static void rfc_port_sm_disc_wait_ua (tPORT *p_port, UINT16 event, void *p_data);

static void rfc_port_uplink_data (tPORT *p_port, BT_HDR *p_buf);

static void rfc_set_port_state(tPORT_STATE *port_pars, MX_FRAME *p_frame);


/*******************************************************************************
**
** Function         rfc_port_sm_execute
**
** Description      This function sends port events through the state
**                  machine.
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_execute (tPORT *p_port, UINT16 event, void *p_data)
{
    if (!p_port) {
        RFCOMM_TRACE_WARNING ("NULL port event %d", event);
        return;
    }

    switch (p_port->rfc.state) {
    case RFC_STATE_CLOSED:
        rfc_port_sm_state_closed (p_port, event, p_data);
        break;

    case RFC_STATE_SABME_WAIT_UA:
        rfc_port_sm_sabme_wait_ua (p_port, event, p_data);
        break;

    case RFC_STATE_ORIG_WAIT_SEC_CHECK:
        rfc_port_sm_orig_wait_sec_check (p_port, event, p_data);
        break;

    case RFC_STATE_TERM_WAIT_SEC_CHECK:
        rfc_port_sm_term_wait_sec_check (p_port, event, p_data);
        break;

    case RFC_STATE_OPENED:
        rfc_port_sm_opened (p_port, event, p_data);
        break;

    case RFC_STATE_DISC_WAIT_UA:
        rfc_port_sm_disc_wait_ua (p_port, event, p_data);
        break;
    }
}


/*******************************************************************************
**
** Function         rfc_port_sm_state_closed
**
** Description      This function handles events when the port is in
**                  CLOSED state. This state exists when port is
**                  being initially established.
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_state_closed (tPORT *p_port, UINT16 event, void *p_data)
{
    switch (event) {
    case RFC_EVENT_OPEN:
        p_port->rfc.state = RFC_STATE_ORIG_WAIT_SEC_CHECK;
        btm_sec_mx_access_request (p_port->rfc.p_mcb->bd_addr, BT_PSM_RFCOMM, TRUE,
                                   BTM_SEC_PROTO_RFCOMM, (UINT32)(p_port->dlci / 2),
                                   &rfc_sec_check_complete, p_port);
        return;

    case RFC_EVENT_CLOSE:
        break;

    case RFC_EVENT_CLEAR:
        return;

    case RFC_EVENT_DATA:
        GKI_freebuf (p_data);
        break;

    case RFC_EVENT_SABME:
        /* make sure the multiplexer disconnect timer is not running (reconnect case) */
        rfc_timer_stop(p_port->rfc.p_mcb );

        /* Open will be continued after security checks are passed */
        p_port->rfc.state = RFC_STATE_TERM_WAIT_SEC_CHECK;
        btm_sec_mx_access_request (p_port->rfc.p_mcb->bd_addr, BT_PSM_RFCOMM, FALSE,
                                   BTM_SEC_PROTO_RFCOMM, (UINT32)(p_port->dlci / 2),
                                   &rfc_sec_check_complete, p_port);
        return;

    case RFC_EVENT_UA:
        return;

    case RFC_EVENT_DM:
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_UIH:
        GKI_freebuf (p_data);
        rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, FALSE);
        return;

    case RFC_EVENT_DISC:
        rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, FALSE);
        return;

    case RFC_EVENT_TIMEOUT:
        Port_TimeOutCloseMux( p_port->rfc.p_mcb ) ;
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;
    }

    RFCOMM_TRACE_WARNING ("Port state closed Event ignored %d", event);
    return;
}

/*******************************************************************************
**
** Function         rfc_port_sm_sabme_wait_ua
**
** Description      This function handles events when SABME on the DLC was
**                  sent and SM is waiting for UA or DM.
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_sabme_wait_ua (tPORT *p_port, UINT16 event, void *p_data)
{
    switch (event) {
    case RFC_EVENT_OPEN:
    case RFC_EVENT_ESTABLISH_RSP:
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;

    case RFC_EVENT_CLOSE:
        rfc_port_timer_start (p_port, RFC_DISC_TIMEOUT);
        rfc_send_disc (p_port->rfc.p_mcb, p_port->dlci);
        p_port->rfc.expected_rsp = 0;
        p_port->rfc.state = RFC_STATE_DISC_WAIT_UA;
        return;

    case RFC_EVENT_CLEAR:
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DATA:
        GKI_freebuf (p_data);
        break;

    case RFC_EVENT_UA:
        rfc_port_timer_stop (p_port);
        p_port->rfc.state = RFC_STATE_OPENED;
        PORT_DlcEstablishCnf (p_port->rfc.p_mcb, p_port->dlci, p_port->rfc.p_mcb->peer_l2cap_mtu, RFCOMM_SUCCESS);
        return;

    case RFC_EVENT_DM:
        p_port->rfc.p_mcb->is_disc_initiator = TRUE;
        PORT_DlcEstablishCnf (p_port->rfc.p_mcb, p_port->dlci, p_port->rfc.p_mcb->peer_l2cap_mtu, RFCOMM_ERROR);
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DISC:
        rfc_send_ua (p_port->rfc.p_mcb, p_port->dlci);
        PORT_DlcEstablishCnf (p_port->rfc.p_mcb, p_port->dlci, p_port->rfc.p_mcb->peer_l2cap_mtu, RFCOMM_ERROR);
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_SABME:
        /* Continue to wait for the UA the SABME this side sent */
        rfc_send_ua (p_port->rfc.p_mcb, p_port->dlci);
        return;

    case RFC_EVENT_UIH:
        GKI_freebuf (p_data);
        return;

    case RFC_EVENT_TIMEOUT:
        p_port->rfc.state = RFC_STATE_CLOSED;
        PORT_DlcEstablishCnf (p_port->rfc.p_mcb, p_port->dlci, p_port->rfc.p_mcb->peer_l2cap_mtu, RFCOMM_ERROR);
        return;
    }
    RFCOMM_TRACE_WARNING ("Port state sabme_wait_ua Event ignored %d", event);
}


/*******************************************************************************
**
** Function         rfc_port_sm_term_wait_sec_check
**
** Description      This function handles events for the port in the
**                  WAIT_SEC_CHECK state.  SABME has been received from the
**                  peer and Security Manager verifes BD_ADDR, before we can
**                  send ESTABLISH_IND to the Port entity
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_term_wait_sec_check (tPORT *p_port, UINT16 event, void *p_data)
{
    switch (event) {
    case RFC_EVENT_SEC_COMPLETE:
        if (*((UINT8 *)p_data) != BTM_SUCCESS) {
            /* Authentication/authorization failed.  If link is still  */
            /* up send DM and check if we need to start inactive timer */
            if (p_port->rfc.p_mcb) {
                rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, TRUE);
                p_port->rfc.p_mcb->is_disc_initiator = TRUE;
                port_rfc_closed (p_port, PORT_SEC_FAILED);
            }
        } else {
            PORT_DlcEstablishInd (p_port->rfc.p_mcb, p_port->dlci, p_port->rfc.p_mcb->peer_l2cap_mtu);
        }
        return;

    case RFC_EVENT_OPEN:
    case RFC_EVENT_CLOSE:
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;

    case RFC_EVENT_CLEAR:
        btm_sec_abort_access_req (p_port->rfc.p_mcb->bd_addr);
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DATA:
        RFCOMM_TRACE_ERROR ("Port error state Term Wait Sec event Data");
        GKI_freebuf (p_data);
        return;

    case RFC_EVENT_SABME:
        /* Ignore SABME retransmission if client dares to do so */
        return;

    case RFC_EVENT_DISC:
        btm_sec_abort_access_req (p_port->rfc.p_mcb->bd_addr);
        p_port->rfc.state = RFC_STATE_CLOSED;
        rfc_send_ua (p_port->rfc.p_mcb, p_port->dlci);

        PORT_DlcReleaseInd (p_port->rfc.p_mcb, p_port->dlci);
        return;

    case RFC_EVENT_UIH:
        GKI_freebuf (p_data);
        return;

    case RFC_EVENT_ESTABLISH_RSP:
        if (*((UINT8 *)p_data) != RFCOMM_SUCCESS) {
            if (p_port->rfc.p_mcb) {
                rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, TRUE);
            }
        } else {
            rfc_send_ua (p_port->rfc.p_mcb, p_port->dlci);
            p_port->rfc.state = RFC_STATE_OPENED;
        }
        return;
    }
    RFCOMM_TRACE_WARNING ("Port state term_wait_sec_check Event ignored %d", event);
}


/*******************************************************************************
**
** Function         rfc_port_sm_orig_wait_sec_check
**
** Description      This function handles events for the port in the
**                  ORIG_WAIT_SEC_CHECK state.  RFCOMM is waiting for Security
**                  manager to finish before sending SABME to the peer
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_orig_wait_sec_check (tPORT *p_port, UINT16 event, void *p_data)
{
    switch (event) {
    case RFC_EVENT_SEC_COMPLETE:
        if (*((UINT8 *)p_data) != BTM_SUCCESS) {
            p_port->rfc.p_mcb->is_disc_initiator = TRUE;
            PORT_DlcEstablishCnf (p_port->rfc.p_mcb, p_port->dlci, 0, RFCOMM_SECURITY_ERR);
            rfc_port_closed (p_port);
            return;
        }
        rfc_send_sabme (p_port->rfc.p_mcb, p_port->dlci);
        rfc_port_timer_start (p_port, RFC_PORT_T1_TIMEOUT);
        p_port->rfc.state = RFC_STATE_SABME_WAIT_UA;
        return;

    case RFC_EVENT_OPEN:
    case RFC_EVENT_SABME:       /* Peer should not use the same dlci */
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;

    case RFC_EVENT_CLOSE:
        btm_sec_abort_access_req (p_port->rfc.p_mcb->bd_addr);
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DATA:
        RFCOMM_TRACE_ERROR ("Port error state Orig Wait Sec event Data");
        GKI_freebuf (p_data);
        return;

    case RFC_EVENT_UIH:
        GKI_freebuf (p_data);
        return;
    }
    RFCOMM_TRACE_WARNING ("Port state orig_wait_sec_check Event ignored %d", event);
}


/*******************************************************************************
**
** Function         rfc_port_sm_opened
**
** Description      This function handles events for the port in the OPENED
**                  state
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_opened (tPORT *p_port, UINT16 event, void *p_data)
{
    switch (event) {
    case RFC_EVENT_OPEN:
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;

    case RFC_EVENT_CLOSE:
        rfc_port_timer_start (p_port, RFC_DISC_TIMEOUT);
        rfc_send_disc (p_port->rfc.p_mcb, p_port->dlci);
        p_port->rfc.expected_rsp = 0;
        p_port->rfc.state = RFC_STATE_DISC_WAIT_UA;
        return;

    case RFC_EVENT_CLEAR:
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DATA:
        /* Send credits in the frame.  Pass them in the layer specific member of the hdr. */
        /* There might be an initial case when we reduced rx_max and credit_rx is still */
        /* bigger.  Make sure that we do not send 255 */
        if ((p_port->rfc.p_mcb->flow == PORT_FC_CREDIT)
                && (((BT_HDR *)p_data)->len < p_port->peer_mtu)
                && (!p_port->rx.user_fc)
                && (p_port->credit_rx_max > p_port->credit_rx)) {
            ((BT_HDR *)p_data)->layer_specific = (UINT8) (p_port->credit_rx_max - p_port->credit_rx);
            p_port->credit_rx = p_port->credit_rx_max;
        } else {
            ((BT_HDR *)p_data)->layer_specific = 0;
        }
        rfc_send_buf_uih (p_port->rfc.p_mcb, p_port->dlci, (BT_HDR *)p_data);
        rfc_dec_credit (p_port);
        return;

    case RFC_EVENT_UA:
        return;

    case RFC_EVENT_SABME:
        rfc_send_ua (p_port->rfc.p_mcb, p_port->dlci);
        return;

    case RFC_EVENT_DM:
        PORT_DlcReleaseInd (p_port->rfc.p_mcb, p_port->dlci);
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DISC:
        p_port->rfc.state = RFC_STATE_CLOSED;
        rfc_send_ua (p_port->rfc.p_mcb, p_port->dlci);
        if (!GKI_queue_is_empty(&p_port->rx.queue)) {
            /* give a chance to upper stack to close port properly */
            RFCOMM_TRACE_DEBUG("port queue is not empty");
            rfc_port_timer_start (p_port, RFC_DISC_TIMEOUT);
        } else {
            PORT_DlcReleaseInd (p_port->rfc.p_mcb, p_port->dlci);
        }
        return;

    case RFC_EVENT_UIH:
        rfc_port_uplink_data (p_port, (BT_HDR *)p_data);
        return;

    case RFC_EVENT_TIMEOUT:
        Port_TimeOutCloseMux( p_port->rfc.p_mcb ) ;
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;
    }
    RFCOMM_TRACE_WARNING ("Port state opened Event ignored %d", event);
}


/*******************************************************************************
**
** Function         rfc_port_sm_disc_wait_ua
**
** Description      This function handles events when DISC on the DLC was
**                  sent and SM is waiting for UA or DM.
**
** Returns          void
**
*******************************************************************************/
void rfc_port_sm_disc_wait_ua (tPORT *p_port, UINT16 event, void *p_data)
{
    switch (event) {
    case RFC_EVENT_OPEN:
    case RFC_EVENT_ESTABLISH_RSP:
        RFCOMM_TRACE_ERROR ("Port error state %d event %d", p_port->rfc.state, event);
        return;

    case RFC_EVENT_CLEAR:
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_DATA:
        GKI_freebuf (p_data);
        return;

    case RFC_EVENT_UA:
        p_port->rfc.p_mcb->is_disc_initiator = TRUE;
    /* Case falls through */

    case RFC_EVENT_DM:
        rfc_port_closed (p_port);
        return;

    case RFC_EVENT_SABME:
        rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, TRUE);
        return;

    case RFC_EVENT_DISC:
        rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, TRUE);
        return;

    case RFC_EVENT_UIH:
        GKI_freebuf (p_data);
        rfc_send_dm (p_port->rfc.p_mcb, p_port->dlci, FALSE);
        return;

    case RFC_EVENT_TIMEOUT:
        rfc_port_closed (p_port);
        return;
    }

    RFCOMM_TRACE_WARNING ("Port state disc_wait_ua Event ignored %d", event);
}


/*******************************************************************************
**
** Function         rfc_port_uplink_data
**
** Description      This function handles uplink information data frame.
**
*******************************************************************************/
void rfc_port_uplink_data (tPORT *p_port, BT_HDR *p_buf)
{
    PORT_DataInd (p_port->rfc.p_mcb, p_port->dlci, p_buf);
}


/*******************************************************************************
**
** Function         rfc_process_pn
**
** Description      This function handles DLC parameter negotiation frame.
**                  Record MTU and pass indication to the upper layer.
**
*******************************************************************************/
void rfc_process_pn (tRFC_MCB *p_mcb, BOOLEAN is_command, MX_FRAME *p_frame)
{
    tPORT *p_port;
    UINT8 dlci = p_frame->dlci;

    if (is_command) {
        /* Ignore if Multiplexer is being shut down */
        if (p_mcb->state != RFC_MX_STATE_DISC_WAIT_UA) {
            PORT_ParNegInd (p_mcb, dlci, p_frame->u.pn.mtu,
                            p_frame->u.pn.conv_layer, p_frame->u.pn.k);
        } else {
            rfc_send_dm(p_mcb, dlci, FALSE);
            RFCOMM_TRACE_WARNING("***** MX PN while disconnecting *****");
        }

        return;
    }
    /* If we are not awaiting response just ignore it */
    p_port = port_find_mcb_dlci_port (p_mcb, dlci);
    if ((p_port == NULL) || !(p_port->rfc.expected_rsp & RFC_RSP_PN)) {
        return;
    }

    p_port->rfc.expected_rsp &= ~RFC_RSP_PN;

    rfc_port_timer_stop (p_port);

    PORT_ParNegCnf (p_mcb, dlci, p_frame->u.pn.mtu,
                    p_frame->u.pn.conv_layer, p_frame->u.pn.k);
}


/*******************************************************************************
**
** Function         rfc_process_rpn
**
** Description      This function handles Remote DLC parameter negotiation
**                  command/response.  Pass command to the user.
**
*******************************************************************************/
void rfc_process_rpn (tRFC_MCB *p_mcb, BOOLEAN is_command,
                      BOOLEAN is_request, MX_FRAME *p_frame)
{
    tPORT_STATE port_pars;
    tPORT       *p_port;

    if ((p_port = port_find_mcb_dlci_port (p_mcb, p_frame->dlci)) == NULL) {
        /* This is the first command on the port */
        if (is_command) {

            memset(&port_pars, 0, sizeof(tPORT_STATE));
            rfc_set_port_state(&port_pars, p_frame);

            PORT_PortNegInd(p_mcb, p_frame->dlci, &port_pars, p_frame->u.rpn.param_mask);
        }
        return;
    }

    if (is_command && is_request) {
        /* This is the special situation when peer just request local pars */
        port_pars = p_port->peer_port_pars;
        rfc_send_rpn (p_mcb, p_frame->dlci, FALSE, &p_port->peer_port_pars, 0);
        return;
    }

    port_pars = p_port->peer_port_pars;

    rfc_set_port_state(&port_pars, p_frame);

    if (is_command) {
        PORT_PortNegInd (p_mcb, p_frame->dlci, &port_pars, p_frame->u.rpn.param_mask);
        return;
    }

    /* If we are not awaiting response just ignore it */
    p_port = port_find_mcb_dlci_port (p_mcb, p_frame->dlci);
    if ((p_port == NULL) || !(p_port->rfc.expected_rsp & (RFC_RSP_RPN | RFC_RSP_RPN_REPLY))) {
        return;
    }

    /* If we sent a request for port parameters to the peer he is replying with */
    /* mask 0. */
    rfc_port_timer_stop (p_port);

    if (p_port->rfc.expected_rsp & RFC_RSP_RPN_REPLY) {
        p_port->rfc.expected_rsp &= ~RFC_RSP_RPN_REPLY;

        p_port->peer_port_pars = port_pars;

        if ((port_pars.fc_type == (RFCOMM_FC_RTR_ON_INPUT | RFCOMM_FC_RTR_ON_OUTPUT))
                || (port_pars.fc_type == (RFCOMM_FC_RTC_ON_INPUT | RFCOMM_FC_RTC_ON_OUTPUT))) {
            /* This is satisfactory port parameters.  Set mask as it was Ok */
            p_frame->u.rpn.param_mask = RFCOMM_RPN_PM_MASK;
        } else {
            /* Current peer parameters are not good, try to fix them */
            p_port->peer_port_pars.fc_type = (RFCOMM_FC_RTR_ON_INPUT | RFCOMM_FC_RTR_ON_OUTPUT);

            p_port->rfc.expected_rsp |= RFC_RSP_RPN;
            rfc_send_rpn (p_mcb, p_frame->dlci, TRUE, &p_port->peer_port_pars,
                          RFCOMM_RPN_PM_RTR_ON_INPUT | RFCOMM_RPN_PM_RTR_ON_OUTPUT);
            rfc_port_timer_start (p_port, RFC_T2_TIMEOUT) ;
            return;
        }
    } else {
        p_port->rfc.expected_rsp &= ~RFC_RSP_RPN;
    }

    /* Check if all suggested parameters were accepted */
    if (((p_frame->u.rpn.param_mask & (RFCOMM_RPN_PM_RTR_ON_INPUT | RFCOMM_RPN_PM_RTR_ON_OUTPUT)) ==
            (RFCOMM_RPN_PM_RTR_ON_INPUT | RFCOMM_RPN_PM_RTR_ON_OUTPUT))
            || ((p_frame->u.rpn.param_mask & (RFCOMM_RPN_PM_RTC_ON_INPUT | RFCOMM_RPN_PM_RTC_ON_OUTPUT)) ==
                (RFCOMM_RPN_PM_RTC_ON_INPUT | RFCOMM_RPN_PM_RTC_ON_OUTPUT))) {
        PORT_PortNegCnf (p_mcb, p_port->dlci, &port_pars, RFCOMM_SUCCESS);
        return;
    }

    /* If we were proposing RTR flow control try RTC flow control */
    /* If we were proposing RTC flow control try no flow control */
    /* otherwise drop the connection */
    if (p_port->peer_port_pars.fc_type == (RFCOMM_FC_RTR_ON_INPUT | RFCOMM_FC_RTR_ON_OUTPUT)) {
        /* Current peer parameters are not good, try to fix them */
        p_port->peer_port_pars.fc_type = (RFCOMM_FC_RTC_ON_INPUT | RFCOMM_FC_RTC_ON_OUTPUT);

        p_port->rfc.expected_rsp |= RFC_RSP_RPN;

        rfc_send_rpn (p_mcb, p_frame->dlci, TRUE, &p_port->peer_port_pars,
                      RFCOMM_RPN_PM_RTC_ON_INPUT | RFCOMM_RPN_PM_RTC_ON_OUTPUT);
        rfc_port_timer_start (p_port, RFC_T2_TIMEOUT) ;
        return;
    }

    /* Other side does not support flow control */
    if (p_port->peer_port_pars.fc_type == (RFCOMM_FC_RTC_ON_INPUT | RFCOMM_FC_RTC_ON_OUTPUT)) {
        p_port->peer_port_pars.fc_type = RFCOMM_FC_OFF;
        PORT_PortNegCnf (p_mcb, p_port->dlci, &port_pars, RFCOMM_SUCCESS);
    }
}


/*******************************************************************************
**
** Function         rfc_process_msc
**
** Description      This function handles Modem Status Command.
**                  Pass command to the user.
**
*******************************************************************************/
void rfc_process_msc (tRFC_MCB *p_mcb, BOOLEAN is_command, MX_FRAME *p_frame)
{
    tPORT_CTRL pars;
    tPORT      *p_port;
    UINT8      modem_signals = p_frame->u.msc.signals;
    BOOLEAN    new_peer_fc = FALSE;

    p_port = port_find_mcb_dlci_port (p_mcb, p_frame->dlci);
    if (p_port == NULL) {
        return;
    }

    pars.modem_signal = 0;

    if (modem_signals & RFCOMM_MSC_RTC) {
        pars.modem_signal |= MODEM_SIGNAL_DTRDSR;
    }

    if (modem_signals & RFCOMM_MSC_RTR) {
        pars.modem_signal |= MODEM_SIGNAL_RTSCTS;
    }

    if (modem_signals & RFCOMM_MSC_IC) {
        pars.modem_signal |= MODEM_SIGNAL_RI;
    }

    if (modem_signals & RFCOMM_MSC_DV) {
        pars.modem_signal |= MODEM_SIGNAL_DCD;
    }

    pars.fc = ((modem_signals & RFCOMM_MSC_FC) == RFCOMM_MSC_FC);

    pars.break_signal     = (p_frame->u.msc.break_present) ?
                            p_frame->u.msc.break_duration : 0;
    pars.discard_buffers  = 0;
    pars.break_signal_seq = RFCOMM_CTRL_BREAK_IN_SEQ;   /* this is default */

    /* Check if this command is passed only to indicate flow control */
    if (is_command) {
        rfc_send_msc (p_mcb, p_frame->dlci, FALSE, &pars);

        if (p_port->rfc.p_mcb->flow != PORT_FC_CREDIT) {
            /* Spec 1.1 indicates that only FC bit is used for flow control */
            p_port->peer_ctrl.fc = new_peer_fc = pars.fc;

            if (new_peer_fc != p_port->tx.peer_fc) {
                PORT_FlowInd (p_mcb, p_frame->dlci, (BOOLEAN)!new_peer_fc);
            }
        }

        PORT_ControlInd (p_mcb, p_frame->dlci, &pars);

        return;
    }

    /* If we are not awaiting response just ignore it */
    if (!(p_port->rfc.expected_rsp & RFC_RSP_MSC)) {
        return;
    }

    p_port->rfc.expected_rsp &= ~RFC_RSP_MSC;

    rfc_port_timer_stop (p_port);

    PORT_ControlCnf (p_port->rfc.p_mcb, p_port->dlci, &pars);
}


/*******************************************************************************
**
** Function         rfc_process_rls
**
** Description      This function handles Remote Line Status command.
**                  Pass command to the user.
**
*******************************************************************************/
void rfc_process_rls (tRFC_MCB *p_mcb, BOOLEAN is_command, MX_FRAME *p_frame)
{
    tPORT *p_port;

    if (is_command) {
        PORT_LineStatusInd (p_mcb, p_frame->dlci, p_frame->u.rls.line_status);
        rfc_send_rls (p_mcb, p_frame->dlci, FALSE, p_frame->u.rls.line_status);
    } else {
        p_port = port_find_mcb_dlci_port (p_mcb, p_frame->dlci);

        /* If we are not awaiting response just ignore it */
        if (!p_port || !(p_port->rfc.expected_rsp & RFC_RSP_RLS)) {
            return;
        }

        p_port->rfc.expected_rsp &= ~RFC_RSP_RLS;

        rfc_port_timer_stop (p_port);
    }
}


/*******************************************************************************
**
** Function         rfc_process_nsc
**
** Description      This function handles None Supported Command frame.
**
*******************************************************************************/
void rfc_process_nsc (tRFC_MCB *p_mcb, MX_FRAME *p_frame)
{
    UNUSED(p_mcb);
    UNUSED(p_frame);
}


/*******************************************************************************
**
** Function         rfc_process_test
**
** Description      This function handles Test frame.  If this is a command
**                  reply to it.  Otherwise pass response to the user.
**
*******************************************************************************/
void rfc_process_test_rsp (tRFC_MCB *p_mcb, BT_HDR *p_buf)
{
    UNUSED(p_mcb);

    GKI_freebuf (p_buf);
}


/*******************************************************************************
**
** Function         rfc_process_fcon
**
** Description      This function handles FCON frame.  The peer entity is able
**                  to receive new information
**
*******************************************************************************/
void rfc_process_fcon (tRFC_MCB *p_mcb, BOOLEAN is_command)
{
    if (is_command) {
        rfc_cb.rfc.peer_rx_disabled = FALSE;

        rfc_send_fcon (p_mcb, FALSE);

        if (!p_mcb->l2cap_congested) {
            PORT_FlowInd (p_mcb, 0, TRUE);
        }
    }
}

/*******************************************************************************
**
** Function         rfc_process_fcoff
**
** Description      This function handles FCOFF frame.  The peer entity is unable
**                  to receive new information
**
*******************************************************************************/
void rfc_process_fcoff (tRFC_MCB *p_mcb, BOOLEAN is_command)
{
    if (is_command) {
        rfc_cb.rfc.peer_rx_disabled = TRUE;

        if (!p_mcb->l2cap_congested) {
            PORT_FlowInd (p_mcb, 0, FALSE);
        }

        rfc_send_fcoff (p_mcb, FALSE);
    }
}


/*******************************************************************************
**
** Function         rfc_process_l2cap_congestion
**
** Description      This function handles L2CAP congestion messages
**
*******************************************************************************/
void rfc_process_l2cap_congestion (tRFC_MCB *p_mcb, BOOLEAN is_congested)
{
    p_mcb->l2cap_congested = is_congested;

    if (!is_congested) {
        rfc_check_send_cmd(p_mcb, NULL);
    }

    if (!rfc_cb.rfc.peer_rx_disabled) {
        if (!is_congested) {
            PORT_FlowInd (p_mcb, 0, TRUE);
        } else {
            PORT_FlowInd (p_mcb, 0, FALSE);
        }
    }
}

/*******************************************************************************
**
** Function         rfc_set_port_pars
**
** Description      This function sets the tPORT_STATE structure given a p_frame.
**
*******************************************************************************/

void rfc_set_port_state(tPORT_STATE *port_pars, MX_FRAME *p_frame)
{
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_BIT_RATE) {
        port_pars->baud_rate   = p_frame->u.rpn.baud_rate;
    }
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_DATA_BITS) {
        port_pars->byte_size   = p_frame->u.rpn.byte_size;
    }
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_STOP_BITS) {
        port_pars->stop_bits   = p_frame->u.rpn.stop_bits;
    }
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_PARITY) {
        port_pars->parity      = p_frame->u.rpn.parity;
    }
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_PARITY_TYPE) {
        port_pars->parity_type = p_frame->u.rpn.parity_type;
    }
    if (p_frame->u.rpn.param_mask & (RFCOMM_RPN_PM_XONXOFF_ON_INPUT |
                                     RFCOMM_RPN_PM_XONXOFF_ON_OUTPUT |
                                     RFCOMM_RPN_PM_RTR_ON_INPUT |
                                     RFCOMM_RPN_PM_RTR_ON_OUTPUT |
                                     RFCOMM_RPN_PM_RTC_ON_INPUT |
                                     RFCOMM_RPN_PM_RTC_ON_OUTPUT)) {
        port_pars->fc_type     = p_frame->u.rpn.fc_type;
    }
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_XON_CHAR) {
        port_pars->xon_char    = p_frame->u.rpn.xon_char;
    }
    if (p_frame->u.rpn.param_mask & RFCOMM_RPN_PM_XOFF_CHAR) {
        port_pars->xoff_char   = p_frame->u.rpn.xoff_char;
    }
}