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path: root/cesar/tools/sniffer_phy/src/mme.c
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/* Cesar project {{{
 *
 * Copyright (C) 2010 Spidcom
 *
 * <<<Licence>>>
 *
 * }}} */
/**
 * \file    src/mme.c
 * \brief   MME encoding/decoding.
 * \ingroup sniffer_phy
 *
 * Receive setup MME and send confirmation MME and sniffer MME.
 */
#include "common/std.h"

#include "lib/bitstream.h"
#include "lib/swap.h"
#include "common/defs/homeplugAV.h"
#include "common/defs/ethernet.h"

#include <setjmp.h>

#include "inc/context.h"

#include "cp/mme.h"

/** Data about a MME buffer. */
struct mme_buffer_t
{
    /** Bitstream context. */
    bitstream_t bitstream;
    /** Source MAC address. */
    mac_t sa;
    /** Destination MAC address. */
    mac_t da;
    /** Longjmp context in case of underflow. */
    jmp_buf jump_env;
    /** Buffer address (for TX). */
    u8 *buffer;
};
typedef struct mme_buffer_t mme_buffer_t;

void
mme_init (sniffer_phy_t *ctx)
{
    dbg_assert (ctx);
    /* Initialise context. */
    ctx->mme.mac = 0;
    ctx->mme.mac_sniffer = 0;
}

/**
 * Prepare an MME buffer and fill header.
 * \param  ctx  sniffer context
 * \param  mme  mme data
 * \param  da  destination MAC address
 * \param  mmtype  MMTYPE
 * \return  true on success
 */
static bool
mme_send_prepare (sniffer_phy_t *ctx, mme_buffer_t *mme, mac_t da,
                  u16 mmtype)
{
    dbg_assert (ctx);
    dbg_assert (mme);
    /* Initialise MME data. */
    mme->da = da;
    mme->sa = ctx->mme.mac;
    /* Ask for a new buffer. */
    mme->buffer = lhle_buffer_get (ctx);
    /* Build header. */
    if (mme->buffer)
    {
        bitstream_write_init (&mme->bitstream, mme->buffer,
                              ETH_PACKET_MAX_SIZE);
        bitstream_write_large (&mme->bitstream, mme->da, 48);
        bitstream_write_large (&mme->bitstream, mme->sa, 48);
        bitstream_write (&mme->bitstream, swap16 (HPAV_MTYPE_MME), 16);
        bitstream_write (&mme->bitstream, HPAV_MMV1, 8);
        bitstream_write (&mme->bitstream, mmtype, 16);
        bitstream_write (&mme->bitstream, 0, 16);
        return true;
    }
    else
        return false;
}

/**
 * Finalise and send an MME.
 * \param  ctx  sniffer context
 * \param  mme  mme data
 */
static void
mme_send (sniffer_phy_t *ctx, mme_buffer_t *mme)
{
    dbg_assert (ctx);
    dbg_assert (mme);
    uint bits = bitstream_write_finalise (&mme->bitstream);
    lhle_send (ctx, mme->buffer, CEIL_DIV (bits, 8));
}

/**
 * Send a DRV confirmation.
 * \param  ctx  sniffer context
 * \param  mme  mme data
 * \param  mmtype  request MMTYPE
 * \param  result  result byte
 */
static void
mme_send_drv_any_cnf (sniffer_phy_t *ctx, mme_buffer_t *mme, u16 mmtype,
                      u8 result)
{
    mme_buffer_t cnf;
    dbg_assert (ctx);
    dbg_assert (mme);
    /* Prepare header. */
    if (mme_send_prepare (ctx, &cnf, mme->sa,
                          CP_MSG_MMTYPE_BASE (mmtype) + CP_MME_CNF))
    {
        /* Write result. */
        bitstream_write (&cnf.bitstream, result, 8);
        /* Send MME. */
        mme_send (ctx, &cnf);
    }
}

/**
 * Handle a DRV_STA_SET_MAC_ADDR.REQ.
 * \param  ctx  sniffer context
 * \param  mme  mme data
 */
static void
mme_handle_drv_sta_set_mac_addr_req (sniffer_phy_t *ctx, mme_buffer_t *mme)
{
    dbg_assert (ctx);
    dbg_assert (mme);
    /* Take mac address. */
    ctx->mme.mac = bitstream_read_large (&mme->bitstream, 48);
    /* Acknowledge. */
    mme_send_drv_any_cnf (ctx, mme, DRV_STA_SET_MAC_ADDR_REQ, 0);
}

/**
 * Decode and dispatch an MME.
 * \param  ctx  sniffer context
 * \param  mme  mme data
 */
static void
mme_handle_decode (sniffer_phy_t *ctx, mme_buffer_t *mme)
{
    dbg_assert (ctx);
    dbg_assert (mme);
    /* Catch underflows. */
    if (setjmp (mme->jump_env) == 0)
    {
        /* Decode MAC header. */
        mme->da = bitstream_read_large (&mme->bitstream, 48);
        mme->sa = bitstream_read_large (&mme->bitstream, 48);
        u16 ethertype = bitstream_read (&mme->bitstream, 16);
        if (ethertype != swap16 (HPAV_MTYPE_MME))
            return;
        /* Decode MME header. */
        u8 mmv = bitstream_read (&mme->bitstream, 8);
        if (mmv > HPAV_MMV_MAX)
            return;
        u16 mmtype = bitstream_read (&mme->bitstream, 16);
        u16 fmi = bitstream_read (&mme->bitstream, 16);
        if (fmi != 0)
            return;
        /* Dispatch. */
        switch (mmtype)
        {
        case DRV_STA_SET_MAC_ADDR_REQ:
            mme_handle_drv_sta_set_mac_addr_req (ctx, mme);
            break;
        case DRV_STA_SET_CCO_PREF_REQ:
        case DRV_STA_SET_WAS_CCO_REQ:
        case DRV_STA_SET_SL_REQ:
        case DRV_STA_SET_M_STA_HFID_REQ:
        case DRV_STA_SET_U_STA_HFID_REQ:
        case DRV_STA_SET_AVLN_HFID_REQ:
        case DRV_STA_SET_TONEMASK_REQ:
        case DRV_STA_MAC_START_REQ:
        case DRV_STA_SET_KEY_REQ:
        case DRV_STA_SET_DAK_REQ:
            /* Acknowledge, but ignore. */
            mme_send_drv_any_cnf (ctx, mme, mmtype, 0);
            break;
        }
    }
}

/**
 * Called on bitstream underflow.
 * \param  bitstream  bitstream context
 * \param  user_data  mme data
 */
static void
mme_handle_underflow (bitstream_t *bitstream, void *user_data)
{
    mme_buffer_t *mme = user_data;
    dbg_assert (bitstream);
    dbg_assert (mme);
    /* Long jump to exit this trap. */
    longjmp (mme->jump_env, -1);
}

void
mme_handle (sniffer_phy_t *ctx, const u8 *buffer, uint length)
{
    dbg_assert (ctx);
    dbg_assert (buffer);
    dbg_assert (length >= ETH_PACKET_MIN_SIZE_ALLOWED);
    /* Setup MME buffer. */
    mme_buffer_t mme;
    bitstream_read_init (&mme.bitstream, buffer, length);
    bitstream_init_buffer_cb (&mme.bitstream, mme_handle_underflow, &mme);
    mme.buffer = NULL;
    /* Decode. */
    mme_handle_decode (ctx, &mme);
}

void
mme_report_mpdu (sniffer_phy_t *ctx, lowlevel_rx_t *rx)
{
}