LXR linux/drivers/net/wireless/libertas/rx.c

   1/**
   2  * This file contains the handling of RX in wlan driver.
   3  */
   4#include <linux/etherdevice.h>
   5#include <linux/types.h>
   6
   7#include "hostcmd.h"
   8#include "radiotap.h"
   9#include "decl.h"
  10#include "dev.h"
  11#include "wext.h"
  12
  13struct eth803hdr {
  14        u8 dest_addr[6];
  15        u8 src_addr[6];
  16        u16 h803_len;
  17} __attribute__ ((packed));
  18
  19struct rfc1042hdr {
  20        u8 llc_dsap;
  21        u8 llc_ssap;
  22        u8 llc_ctrl;
  23        u8 snap_oui[3];
  24        u16 snap_type;
  25} __attribute__ ((packed));
  26
  27struct rxpackethdr {
  28        struct eth803hdr eth803_hdr;
  29        struct rfc1042hdr rfc1042_hdr;
  30} __attribute__ ((packed));
  31
  32struct rx80211packethdr {
  33        struct rxpd rx_pd;
  34        void *eth80211_hdr;
  35} __attribute__ ((packed));
  36
  37static int process_rxed_802_11_packet(struct lbs_private *priv,
  38        struct sk_buff *skb);
  39
  40/**
  41 *  @brief This function computes the avgSNR .
  42 *
  43 *  @param priv    A pointer to struct lbs_private structure
  44 *  @return        avgSNR
  45 */
  46static u8 lbs_getavgsnr(struct lbs_private *priv)
  47{
  48        u8 i;
  49        u16 temp = 0;
  50        if (priv->numSNRNF == 0)
  51                return 0;
  52        for (i = 0; i < priv->numSNRNF; i++)
  53                temp += priv->rawSNR[i];
  54        return (u8) (temp / priv->numSNRNF);
  55
  56}
  57
  58/**
  59 *  @brief This function computes the AvgNF
  60 *
  61 *  @param priv    A pointer to struct lbs_private structure
  62 *  @return        AvgNF
  63 */
  64static u8 lbs_getavgnf(struct lbs_private *priv)
  65{
  66        u8 i;
  67        u16 temp = 0;
  68        if (priv->numSNRNF == 0)
  69                return 0;
  70        for (i = 0; i < priv->numSNRNF; i++)
  71                temp += priv->rawNF[i];
  72        return (u8) (temp / priv->numSNRNF);
  73
  74}
  75
  76/**
  77 *  @brief This function save the raw SNR/NF to our internel buffer
  78 *
  79 *  @param priv    A pointer to struct lbs_private structure
  80 *  @param prxpd   A pointer to rxpd structure of received packet
  81 *  @return        n/a
  82 */
  83static void lbs_save_rawSNRNF(struct lbs_private *priv, struct rxpd *p_rx_pd)
  84{
  85        if (priv->numSNRNF < DEFAULT_DATA_AVG_FACTOR)
  86                priv->numSNRNF++;
  87        priv->rawSNR[priv->nextSNRNF] = p_rx_pd->snr;
  88        priv->rawNF[priv->nextSNRNF] = p_rx_pd->nf;
  89        priv->nextSNRNF++;
  90        if (priv->nextSNRNF >= DEFAULT_DATA_AVG_FACTOR)
  91                priv->nextSNRNF = 0;
  92        return;
  93}
  94
  95/**
  96 *  @brief This function computes the RSSI in received packet.
  97 *
  98 *  @param priv    A pointer to struct lbs_private structure
  99 *  @param prxpd   A pointer to rxpd structure of received packet
 100 *  @return        n/a
 101 */
 102static void lbs_compute_rssi(struct lbs_private *priv, struct rxpd *p_rx_pd)
 103{
 104
 105        lbs_deb_enter(LBS_DEB_RX);
 106
 107        lbs_deb_rx("rxpd: SNR %d, NF %d\n", p_rx_pd->snr, p_rx_pd->nf);
 108        lbs_deb_rx("before computing SNR: SNR-avg = %d, NF-avg = %d\n",
 109               priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
 110               priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
 111
 112        priv->SNR[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->snr;
 113        priv->NF[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->nf;
 114        lbs_save_rawSNRNF(priv, p_rx_pd);
 115
 116        priv->SNR[TYPE_RXPD][TYPE_AVG] = lbs_getavgsnr(priv) * AVG_SCALE;
 117        priv->NF[TYPE_RXPD][TYPE_AVG] = lbs_getavgnf(priv) * AVG_SCALE;
 118        lbs_deb_rx("after computing SNR: SNR-avg = %d, NF-avg = %d\n",
 119               priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
 120               priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
 121
 122        priv->RSSI[TYPE_RXPD][TYPE_NOAVG] =
 123            CAL_RSSI(priv->SNR[TYPE_RXPD][TYPE_NOAVG],
 124                     priv->NF[TYPE_RXPD][TYPE_NOAVG]);
 125
 126        priv->RSSI[TYPE_RXPD][TYPE_AVG] =
 127            CAL_RSSI(priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
 128                     priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
 129
 130        lbs_deb_leave(LBS_DEB_RX);
 131}
 132
 133/**
 134 *  @brief This function processes received packet and forwards it
 135 *  to kernel/upper layer
 136 *
 137 *  @param priv    A pointer to struct lbs_private
 138 *  @param skb     A pointer to skb which includes the received packet
 139 *  @return        0 or -1
 140 */
 141int lbs_process_rxed_packet(struct lbs_private *priv, struct sk_buff *skb)
 142{
 143        int ret = 0;
 144        struct net_device *dev = priv->dev;
 145        struct rxpackethdr *p_rx_pkt;
 146        struct rxpd *p_rx_pd;
 147        int hdrchop;
 148        struct ethhdr *p_ethhdr;
 149        const u8 rfc1042_eth_hdr[] = { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
 150
 151        lbs_deb_enter(LBS_DEB_RX);
 152
 153        BUG_ON(!skb);
 154
 155        skb->ip_summed = CHECKSUM_NONE;
 156
 157        if (priv->monitormode)
 158                return process_rxed_802_11_packet(priv, skb);
 159
 160        p_rx_pd = (struct rxpd *) skb->data;
 161        p_rx_pkt = (struct rxpackethdr *) ((u8 *)p_rx_pd +
 162                le32_to_cpu(p_rx_pd->pkt_ptr));
 163        if (priv->mesh_dev) {
 164                if (priv->mesh_fw_ver == MESH_FW_OLD) {
 165                        if (p_rx_pd->rx_control & RxPD_MESH_FRAME)
 166                                dev = priv->mesh_dev;
 167                } else if (priv->mesh_fw_ver == MESH_FW_NEW) {
 168                        if (p_rx_pd->u.bss.bss_num == MESH_IFACE_ID)
 169                                dev = priv->mesh_dev;
 170                }
 171        }
 172
 173        lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data,
 174                 min_t(unsigned int, skb->len, 100));
 175
 176        if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
 177                lbs_deb_rx("rx err: frame received with bad length\n");
 178                dev->stats.rx_length_errors++;
 179                ret = 0;
 180                dev_kfree_skb(skb);
 181                goto done;
 182        }
 183
 184        lbs_deb_rx("rx data: skb->len - pkt_ptr = %d-%zd = %zd\n",
 185                skb->len, (size_t)le32_to_cpu(p_rx_pd->pkt_ptr),
 186                skb->len - (size_t)le32_to_cpu(p_rx_pd->pkt_ptr));
 187
 188        lbs_deb_hex(LBS_DEB_RX, "RX Data: Dest", p_rx_pkt->eth803_hdr.dest_addr,
 189                sizeof(p_rx_pkt->eth803_hdr.dest_addr));
 190        lbs_deb_hex(LBS_DEB_RX, "RX Data: Src", p_rx_pkt->eth803_hdr.src_addr,
 191                sizeof(p_rx_pkt->eth803_hdr.src_addr));
 192
 193        if (memcmp(&p_rx_pkt->rfc1042_hdr,
 194                   rfc1042_eth_hdr, sizeof(rfc1042_eth_hdr)) == 0) {
 195                /*
 196                 *  Replace the 803 header and rfc1042 header (llc/snap) with an
 197                 *    EthernetII header, keep the src/dst and snap_type (ethertype)
 198                 *
 199                 *  The firmware only passes up SNAP frames converting
 200                 *    all RX Data from 802.11 to 802.2/LLC/SNAP frames.
 201                 *
 202                 *  To create the Ethernet II, just move the src, dst address right
 203                 *    before the snap_type.
 204                 */
 205                p_ethhdr = (struct ethhdr *)
 206                    ((u8 *) & p_rx_pkt->eth803_hdr
 207                     + sizeof(p_rx_pkt->eth803_hdr) + sizeof(p_rx_pkt->rfc1042_hdr)
 208                     - sizeof(p_rx_pkt->eth803_hdr.dest_addr)
 209                     - sizeof(p_rx_pkt->eth803_hdr.src_addr)
 210                     - sizeof(p_rx_pkt->rfc1042_hdr.snap_type));
 211
 212                memcpy(p_ethhdr->h_source, p_rx_pkt->eth803_hdr.src_addr,
 213                       sizeof(p_ethhdr->h_source));
 214                memcpy(p_ethhdr->h_dest, p_rx_pkt->eth803_hdr.dest_addr,
 215                       sizeof(p_ethhdr->h_dest));
 216
 217                /* Chop off the rxpd + the excess memory from the 802.2/llc/snap header
 218                 *   that was removed
 219                 */
 220                hdrchop = (u8 *)p_ethhdr - (u8 *)p_rx_pd;
 221        } else {
 222                lbs_deb_hex(LBS_DEB_RX, "RX Data: LLC/SNAP",
 223                        (u8 *) & p_rx_pkt->rfc1042_hdr,
 224                        sizeof(p_rx_pkt->rfc1042_hdr));
 225
 226                /* Chop off the rxpd */
 227                hdrchop = (u8 *)&p_rx_pkt->eth803_hdr - (u8 *)p_rx_pd;
 228        }
 229
 230        /* Chop off the leading header bytes so the skb points to the start of
 231         *   either the reconstructed EthII frame or the 802.2/llc/snap frame
 232         */
 233        skb_pull(skb, hdrchop);
 234
 235        /* Take the data rate from the rxpd structure
 236         * only if the rate is auto
 237         */
 238        if (priv->enablehwauto)
 239                priv->cur_rate = lbs_fw_index_to_data_rate(p_rx_pd->rx_rate);
 240
 241        lbs_compute_rssi(priv, p_rx_pd);
 242
 243        lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
 244        dev->stats.rx_bytes += skb->len;
 245        dev->stats.rx_packets++;
 246
 247        skb->protocol = eth_type_trans(skb, dev);
 248        if (in_interrupt())
 249                netif_rx(skb);
 250        else
 251                netif_rx_ni(skb);
 252
 253        ret = 0;
 254done:
 255        lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
 256        return ret;
 257}
 258EXPORT_SYMBOL_GPL(lbs_process_rxed_packet);
 259
 260/**
 261 *  @brief This function converts Tx/Rx rates from the Marvell WLAN format
 262 *  (see Table 2 in Section 3.1) to IEEE80211_RADIOTAP_RATE units (500 Kb/s)
 263 *
 264 *  @param rate    Input rate
 265 *  @return        Output Rate (0 if invalid)
 266 */
 267static u8 convert_mv_rate_to_radiotap(u8 rate)
 268{
 269        switch (rate) {
 270        case 0:         /*   1 Mbps */
 271                return 2;
 272        case 1:         /*   2 Mbps */
 273                return 4;
 274        case 2:         /* 5.5 Mbps */
 275                return 11;
 276        case 3:         /*  11 Mbps */
 277                return 22;
 278        /* case 4: reserved */
 279        case 5:         /*   6 Mbps */
 280                return 12;
 281        case 6:         /*   9 Mbps */
 282                return 18;
 283        case 7:         /*  12 Mbps */
 284                return 24;
 285        case 8:         /*  18 Mbps */
 286                return 36;
 287        case 9:         /*  24 Mbps */
 288                return 48;
 289        case 10:                /*  36 Mbps */
 290                return 72;
 291        case 11:                /*  48 Mbps */
 292                return 96;
 293        case 12:                /*  54 Mbps */
 294                return 108;
 295        }
 296        lbs_pr_alert("Invalid Marvell WLAN rate %i\n", rate);
 297        return 0;
 298}
 299
 300/**
 301 *  @brief This function processes a received 802.11 packet and forwards it
 302 *  to kernel/upper layer
 303 *
 304 *  @param priv    A pointer to struct lbs_private
 305 *  @param skb     A pointer to skb which includes the received packet
 306 *  @return        0 or -1
 307 */
 308static int process_rxed_802_11_packet(struct lbs_private *priv,
 309        struct sk_buff *skb)
 310{
 311        int ret = 0;
 312        struct net_device *dev = priv->dev;
 313        struct rx80211packethdr *p_rx_pkt;
 314        struct rxpd *prxpd;
 315        struct rx_radiotap_hdr radiotap_hdr;
 316        struct rx_radiotap_hdr *pradiotap_hdr;
 317
 318        lbs_deb_enter(LBS_DEB_RX);
 319
 320        p_rx_pkt = (struct rx80211packethdr *) skb->data;
 321        prxpd = &p_rx_pkt->rx_pd;
 322
 323        // lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data, min(skb->len, 100));
 324
 325        if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
 326                lbs_deb_rx("rx err: frame received with bad length\n");
 327                dev->stats.rx_length_errors++;
 328                ret = -EINVAL;
 329                kfree_skb(skb);
 330                goto done;
 331        }
 332
 333        lbs_deb_rx("rx data: skb->len-sizeof(RxPd) = %d-%zd = %zd\n",
 334               skb->len, sizeof(struct rxpd), skb->len - sizeof(struct rxpd));
 335
 336        /* create the exported radio header */
 337
 338        /* radiotap header */
 339        radiotap_hdr.hdr.it_version = 0;
 340        /* XXX must check this value for pad */
 341        radiotap_hdr.hdr.it_pad = 0;
 342        radiotap_hdr.hdr.it_len = cpu_to_le16 (sizeof(struct rx_radiotap_hdr));
 343        radiotap_hdr.hdr.it_present = cpu_to_le32 (RX_RADIOTAP_PRESENT);
 344        radiotap_hdr.rate = convert_mv_rate_to_radiotap(prxpd->rx_rate);
 345        /* XXX must check no carryout */
 346        radiotap_hdr.antsignal = prxpd->snr + prxpd->nf;
 347
 348        /* chop the rxpd */
 349        skb_pull(skb, sizeof(struct rxpd));
 350
 351        /* add space for the new radio header */
 352        if ((skb_headroom(skb) < sizeof(struct rx_radiotap_hdr)) &&
 353            pskb_expand_head(skb, sizeof(struct rx_radiotap_hdr), 0, GFP_ATOMIC)) {
 354                lbs_pr_alert("%s: couldn't pskb_expand_head\n", __func__);
 355                ret = -ENOMEM;
 356                kfree_skb(skb);
 357                goto done;
 358        }
 359
 360        pradiotap_hdr = (void *)skb_push(skb, sizeof(struct rx_radiotap_hdr));
 361        memcpy(pradiotap_hdr, &radiotap_hdr, sizeof(struct rx_radiotap_hdr));
 362
 363        /* Take the data rate from the rxpd structure
 364         * only if the rate is auto
 365         */
 366        if (priv->enablehwauto)
 367                priv->cur_rate = lbs_fw_index_to_data_rate(prxpd->rx_rate);
 368
 369        lbs_compute_rssi(priv, prxpd);
 370
 371        lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
 372        dev->stats.rx_bytes += skb->len;
 373        dev->stats.rx_packets++;
 374
 375        skb->protocol = eth_type_trans(skb, priv->rtap_net_dev);
 376        netif_rx(skb);
 377
 378        ret = 0;
 379
 380done:
 381        lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
 382        return ret;
 383}
 384