path: root/stack/rfcomm/rfc_utils.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 collection of utility functions used the RFCOMM unit
 *
 *****************************************************************************/

#include "bt_target.h"
#include "gki.h"

#include "btm_api.h"
#include "btm_int.h"
#include "rfcdefs.h"
#include "port_api.h"
#include "port_ext.h"
#include "port_int.h"
#include "rfc_int.h"
#include "btu.h"

#include <string.h>

/*******************************************************************************
**
** Function         rfc_calc_fcs
**
** Description      Reversed CRC Table , 8-bit, poly=0x07
**                  (GSM 07.10 TS 101 369 V6.3.0)
*******************************************************************************/
static const UINT8 rfc_crctable[] =
{
    0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,  0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
    0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,  0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
    0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,  0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
    0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,  0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,

    0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,  0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
    0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,  0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
    0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,  0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
    0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,  0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,

    0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,  0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
    0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,  0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
    0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,  0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
    0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,  0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,

    0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,  0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
    0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,  0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
    0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,  0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
    0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,  0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
};


/*******************************************************************************
**
** Function         rfc_calc_fcs
**
** Description      This function calculate FCS for the RFCOMM frame
**                  (GSM 07.10 TS 101 369 V6.3.0)
**
** Input            len - number of bytes in the message
**                  p   - points to message
**
*******************************************************************************/
UINT8 rfc_calc_fcs (UINT16 len, UINT8 *p)
{
    UINT8  fcs = 0xFF;

    while (len--)
    {
        fcs = rfc_crctable[fcs ^ *p++];
    }

    /* Ones compliment */
    return (0xFF - fcs);
}


/*******************************************************************************
**
** Function         rfc_check_fcs
**
** Description      This function checks FCS for the RFCOMM frame
**                  (GSM 07.10 TS 101 369 V6.3.0)
**
** Input            len          - number of bytes in the message
**                  p            - points to message
**                  received_fcs - received FCS
**
*******************************************************************************/
BOOLEAN rfc_check_fcs (UINT16 len, UINT8 *p, UINT8 received_fcs)
{
    UINT8  fcs = 0xFF;

    while (len--)
    {
        fcs = rfc_crctable[fcs ^ *p++];
    }

    /* Ones compliment */
    fcs = rfc_crctable[fcs ^ received_fcs];

    /*0xCF is the reversed order of 11110011.*/
    return (fcs == 0xCF);
}


/*******************************************************************************
**
** Function         rfc_alloc_multiplexer_channel
**
** Description      This function returns existing or new control block for
**                  the BD_ADDR.
**
*******************************************************************************/
tRFC_MCB *rfc_alloc_multiplexer_channel (BD_ADDR bd_addr, BOOLEAN is_initiator)
{
    int i, j;
    tRFC_MCB *p_mcb = NULL;

    for (i = 0; i < MAX_BD_CONNECTIONS; i++)
    {
        if ((rfc_cb.port.rfc_mcb[i].state != RFC_MX_STATE_IDLE)
         && (!memcmp (rfc_cb.port.rfc_mcb[i].bd_addr, bd_addr, BD_ADDR_LEN)))
        {
            /* Multiplexer channel found do not change anything */
            /* If there was an inactivity timer running stop it now */
            if (rfc_cb.port.rfc_mcb[i].state == RFC_MX_STATE_CONNECTED)
                rfc_timer_stop (&rfc_cb.port.rfc_mcb[i]);
            return (&rfc_cb.port.rfc_mcb[i]);
        }
    }

    /* connection with bd_addr does not exist */
    for (i = 0, j = rfc_cb.rfc.last_mux + 1; i < MAX_BD_CONNECTIONS; i++, j++)
    {
        if (j >= MAX_BD_CONNECTIONS)
            j = 0;

        p_mcb = &rfc_cb.port.rfc_mcb[j];
        if (rfc_cb.port.rfc_mcb[j].state == RFC_MX_STATE_IDLE)
        {
            /* New multiplexer control block */
            memset (p_mcb, 0, sizeof (tRFC_MCB));
            memcpy (p_mcb->bd_addr, bd_addr, BD_ADDR_LEN);

            GKI_init_q(&p_mcb->cmd_q);

            p_mcb->is_initiator = is_initiator;

            rfc_timer_start (p_mcb, RFC_MCB_INIT_INACT_TIMER);

            rfc_cb.rfc.last_mux = (UINT8) j;
            return (p_mcb);
        }
    }
    return (NULL);
}


/*******************************************************************************
**
** Function         rfc_release_multiplexer_channel
**
** Description      This function returns existing or new control block for
**                  the BD_ADDR.
**
*******************************************************************************/
void rfc_release_multiplexer_channel (tRFC_MCB *p_mcb)
{
    void    *p_buf;

    rfc_timer_stop (p_mcb);

    while ((p_buf = GKI_dequeue(&p_mcb->cmd_q)) != NULL)
        GKI_freebuf(p_buf);

    memset (p_mcb, 0, sizeof (tRFC_MCB));
    p_mcb->state = RFC_MX_STATE_IDLE;
}


/*******************************************************************************
**
** Function         rfc_timer_start
**
** Description      Start RFC Timer
**
*******************************************************************************/
void rfc_timer_start (tRFC_MCB *p_mcb, UINT16 timeout)
{
    TIMER_LIST_ENT *p_tle = &p_mcb->tle;

    RFCOMM_TRACE_EVENT1 ("rfc_timer_start - timeout:%d", timeout);

    p_tle->param = (UINT32)p_mcb;

    btu_start_timer (p_tle, BTU_TTYPE_RFCOMM_MFC, timeout);
}


/*******************************************************************************
**
** Function         rfc_timer_stop
**
** Description      Stop RFC Timer
**
*******************************************************************************/
void rfc_timer_stop (tRFC_MCB *p_mcb)
{
    RFCOMM_TRACE_EVENT0 ("rfc_timer_stop");

    btu_stop_timer (&p_mcb->tle);
}


/*******************************************************************************
**
** Function         rfc_port_timer_start
**
** Description      Start RFC Timer
**
*******************************************************************************/
void rfc_port_timer_start (tPORT *p_port, UINT16 timeout)
{
    TIMER_LIST_ENT *p_tle = &p_port->rfc.tle;

    RFCOMM_TRACE_EVENT1 ("rfc_port_timer_start - timeout:%d", timeout);

    p_tle->param = (UINT32)p_port;

    btu_start_timer (p_tle, BTU_TTYPE_RFCOMM_PORT, timeout);
}


/*******************************************************************************
**
** Function         rfc_port_timer_stop
**
** Description      Stop RFC Timer
**
*******************************************************************************/
void rfc_port_timer_stop (tPORT *p_port)
{
    RFCOMM_TRACE_EVENT0 ("rfc_port_timer_stop");

    btu_stop_timer (&p_port->rfc.tle);
}


/*******************************************************************************
**
** Function         rfc_check_mcb_active
**
** Description      Check if there are any opened ports on the MCB if not
**                  start MCB Inact timer.
**
** Returns          void
**
*******************************************************************************/
void rfc_check_mcb_active (tRFC_MCB *p_mcb)
{
    UINT16 i;

    for (i = 0; i < RFCOMM_MAX_DLCI; i++)
    {
        if (p_mcb->port_inx[i] != 0)
        {
            p_mcb->is_disc_initiator = FALSE;
            return;
        }
    }
    /* The last port was DISCed.  On the client side start disconnecting Mx */
    /* On the server side start inactivity timer */
    if (p_mcb->is_disc_initiator)
    {
        p_mcb->is_disc_initiator = FALSE;
        rfc_mx_sm_execute (p_mcb, RFC_MX_EVENT_CLOSE_REQ, NULL);
    }
    else
        rfc_timer_start (p_mcb, RFC_MCB_RELEASE_INACT_TIMER);
}


/*******************************************************************************
**
** Function         rfcomm_process_timeout
**
** Description      The function called every second to check RFCOMM timers
**
** Returns          void
**
*******************************************************************************/
void rfcomm_process_timeout (TIMER_LIST_ENT  *p_tle)
{
    switch (p_tle->event)
    {
    case BTU_TTYPE_RFCOMM_MFC:
        rfc_mx_sm_execute ((tRFC_MCB *)p_tle->param, RFC_EVENT_TIMEOUT, NULL);
        break;

    case BTU_TTYPE_RFCOMM_PORT:
        rfc_port_sm_execute ((tPORT *)p_tle->param, RFC_EVENT_TIMEOUT, NULL);
        break;

    default:
        break;
    }
}


/*******************************************************************************
**
** Function         rfc_sec_check_complete
**
** Description      The function called when Security Manager finishes
**                  verification of the service side connection
**
** Returns          void
**
*******************************************************************************/
void rfc_sec_check_complete (BD_ADDR bd_addr, void *p_ref_data, UINT8 res)
{
    tPORT *p_port = (tPORT *)p_ref_data;

    /* Verify that PORT is still waiting for Security to complete */
    if (!p_port->in_use
     || ((p_port->rfc.state != RFC_STATE_ORIG_WAIT_SEC_CHECK)
      && (p_port->rfc.state != RFC_STATE_TERM_WAIT_SEC_CHECK)))
        return;

    rfc_port_sm_execute ((tPORT *)p_ref_data, RFC_EVENT_SEC_COMPLETE, &res);
}


/*******************************************************************************
**
** Function         rfc_port_closed
**
** Description      The function is called when port is released based on the
**                  event received from the lower layer, typically L2CAP
**                  connection down, DISC, or DM frame.
**
** Returns          void
**
*******************************************************************************/
void rfc_port_closed (tPORT *p_port)
{
    tRFC_MCB *p_mcb = p_port->rfc.p_mcb;

    RFCOMM_TRACE_DEBUG0 ("rfc_port_closed");

    rfc_port_timer_stop (p_port);

    p_port->rfc.state = RFC_STATE_CLOSED;

    /* If multiplexer channel was up mark it as down */
    if (p_mcb)
    {
        p_mcb->port_inx[p_port->dlci] = 0;

        /* If there are no more ports opened on this MCB release it */
        rfc_check_mcb_active (p_mcb);
    }

    /* Notify port that RFC connection is gone */
    port_rfc_closed (p_port, PORT_CLOSED);
}

/*******************************************************************************
**
** Function         rfc_inc_credit
**
** Description      The function is called when a credit is received in a UIH
**                  frame.  It increments the TX credit count, and if data
**                  flow had halted, it restarts it.
**
** Returns          void
**
*******************************************************************************/
void rfc_inc_credit (tPORT *p_port, UINT8 credit)
{
    if (p_port->rfc.p_mcb->flow == PORT_FC_CREDIT)
    {
        p_port->credit_tx += credit;

        RFCOMM_TRACE_EVENT1 ("rfc_inc_credit:%d", p_port->credit_tx);

        if (p_port->tx.peer_fc == TRUE)
            PORT_FlowInd(p_port->rfc.p_mcb, p_port->dlci, TRUE);
    }
}

/*******************************************************************************
**
** Function         rfc_dec_credit
**
** Description      The function is called when a UIH frame of user data is
**                  sent.  It decrements the credit count.  If credit count
**                  Reaches zero, peer_fc is set.
**
** Returns          void
**
*******************************************************************************/
void rfc_dec_credit (tPORT *p_port)
{
    if (p_port->rfc.p_mcb->flow == PORT_FC_CREDIT)
    {
        if (p_port->credit_tx > 0)
            p_port->credit_tx--;

        if (p_port->credit_tx == 0)
            p_port->tx.peer_fc = TRUE;
    }
}


/*******************************************************************************
**
** Function         rfc_check_send_cmd
**
** Description      This function is called to send an RFCOMM command message
**                  or to handle the RFCOMM command message queue.
**
** Returns          void
**
*******************************************************************************/
void rfc_check_send_cmd(tRFC_MCB *p_mcb, BT_HDR *p_buf)
{
    BT_HDR  *p;

    /* if passed a buffer queue it */
    if (p_buf != NULL)
    {
        GKI_enqueue(&p_mcb->cmd_q, p_buf);
    }

    /* handle queue if L2CAP not congested */
    while (p_mcb->l2cap_congested == FALSE)
    {
        if ((p = (BT_HDR *) GKI_dequeue(&p_mcb->cmd_q)) == NULL)
        {
            break;
        }


        L2CA_DataWrite (p_mcb->lcid, p);
    }
}