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

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/**
* This file contains the handling of RX in wlan driver.
*/
#include <linux/etherdevice.h>
#include <linux/types.h>
#include "host.h"
#include "radiotap.h"
#include "decl.h"
#include "dev.h"
#include "wext.h"
struct eth803hdr {
u8 dest_addr[6];
u8 src_addr[6];
u16 h803_len;
} __attribute__ ((packed));
struct rfc1042hdr {
u8 llc_dsap;
u8 llc_ssap;
u8 llc_ctrl;
u8 snap_oui[3];
u16 snap_type;
} __attribute__ ((packed));
struct rxpackethdr {
struct eth803hdr eth803_hdr;
struct rfc1042hdr rfc1042_hdr;
} __attribute__ ((packed));
struct rx80211packethdr {
struct rxpd rx_pd;
void *eth80211_hdr;
} __attribute__ ((packed));
static int process_rxed_802_11_packet(struct lbs_private *priv,
struct sk_buff *skb);
/**
* @brief This function computes the avgSNR .
*
* @param priv A pointer to struct lbs_private structure
* @return avgSNR
*/
static u8 lbs_getavgsnr(struct lbs_private *priv)
{
u8 i;
u16 temp = 0;
if (priv->numSNRNF == 0)
return 0;
for (i = 0; i < priv->numSNRNF; i++)
temp += priv->rawSNR[i];
return (u8) (temp / priv->numSNRNF);
}
/**
* @brief This function computes the AvgNF
*
* @param priv A pointer to struct lbs_private structure
* @return AvgNF
*/
static u8 lbs_getavgnf(struct lbs_private *priv)
{
u8 i;
u16 temp = 0;
if (priv->numSNRNF == 0)
return 0;
for (i = 0; i < priv->numSNRNF; i++)
temp += priv->rawNF[i];
return (u8) (temp / priv->numSNRNF);
}
/**
* @brief This function save the raw SNR/NF to our internel buffer
*
* @param priv A pointer to struct lbs_private structure
* @param prxpd A pointer to rxpd structure of received packet
* @return n/a
*/
static void lbs_save_rawSNRNF(struct lbs_private *priv, struct rxpd *p_rx_pd)
{
if (priv->numSNRNF < DEFAULT_DATA_AVG_FACTOR)
priv->numSNRNF++;
priv->rawSNR[priv->nextSNRNF] = p_rx_pd->snr;
priv->rawNF[priv->nextSNRNF] = p_rx_pd->nf;
priv->nextSNRNF++;
if (priv->nextSNRNF >= DEFAULT_DATA_AVG_FACTOR)
priv->nextSNRNF = 0;
return;
}
/**
* @brief This function computes the RSSI in received packet.
*
* @param priv A pointer to struct lbs_private structure
* @param prxpd A pointer to rxpd structure of received packet
* @return n/a
*/
static void lbs_compute_rssi(struct lbs_private *priv, struct rxpd *p_rx_pd)
{
lbs_deb_enter(LBS_DEB_RX);
lbs_deb_rx("rxpd: SNR %d, NF %d\n", p_rx_pd->snr, p_rx_pd->nf);
lbs_deb_rx("before computing SNR: SNR-avg = %d, NF-avg = %d\n",
priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
priv->SNR[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->snr;
priv->NF[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->nf;
lbs_save_rawSNRNF(priv, p_rx_pd);
priv->SNR[TYPE_RXPD][TYPE_AVG] = lbs_getavgsnr(priv) * AVG_SCALE;
priv->NF[TYPE_RXPD][TYPE_AVG] = lbs_getavgnf(priv) * AVG_SCALE;
lbs_deb_rx("after computing SNR: SNR-avg = %d, NF-avg = %d\n",
priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
priv->RSSI[TYPE_RXPD][TYPE_NOAVG] =
CAL_RSSI(priv->SNR[TYPE_RXPD][TYPE_NOAVG],
priv->NF[TYPE_RXPD][TYPE_NOAVG]);
priv->RSSI[TYPE_RXPD][TYPE_AVG] =
CAL_RSSI(priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
lbs_deb_leave(LBS_DEB_RX);
}
/**
* @brief This function processes received packet and forwards it
* to kernel/upper layer
*
* @param priv A pointer to struct lbs_private
* @param skb A pointer to skb which includes the received packet
* @return 0 or -1
*/
int lbs_process_rxed_packet(struct lbs_private *priv, struct sk_buff *skb)
{
int ret = 0;
struct net_device *dev = priv->dev;
struct rxpackethdr *p_rx_pkt;
struct rxpd *p_rx_pd;
int hdrchop;
struct ethhdr *p_ethhdr;
const u8 rfc1042_eth_hdr[] = { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
lbs_deb_enter(LBS_DEB_RX);
BUG_ON(!skb);
skb->ip_summed = CHECKSUM_NONE;
if (priv->monitormode)
return process_rxed_802_11_packet(priv, skb);
p_rx_pd = (struct rxpd *) skb->data;
p_rx_pkt = (struct rxpackethdr *) ((u8 *)p_rx_pd +
le32_to_cpu(p_rx_pd->pkt_ptr));
if (priv->mesh_dev) {
if (priv->mesh_fw_ver == MESH_FW_OLD) {
if (p_rx_pd->rx_control & RxPD_MESH_FRAME)
dev = priv->mesh_dev;
} else if (priv->mesh_fw_ver == MESH_FW_NEW) {
if (p_rx_pd->u.bss.bss_num == MESH_IFACE_ID)
dev = priv->mesh_dev;
}
}
lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data,
min_t(unsigned int, skb->len, 100));
if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
lbs_deb_rx("rx err: frame received with bad length\n");
dev->stats.rx_length_errors++;
ret = 0;
dev_kfree_skb(skb);
goto done;
}
lbs_deb_rx("rx data: skb->len - pkt_ptr = %d-%zd = %zd\n",
skb->len, (size_t)le32_to_cpu(p_rx_pd->pkt_ptr),
skb->len - (size_t)le32_to_cpu(p_rx_pd->pkt_ptr));
lbs_deb_hex(LBS_DEB_RX, "RX Data: Dest", p_rx_pkt->eth803_hdr.dest_addr,
sizeof(p_rx_pkt->eth803_hdr.dest_addr));
lbs_deb_hex(LBS_DEB_RX, "RX Data: Src", p_rx_pkt->eth803_hdr.src_addr,
sizeof(p_rx_pkt->eth803_hdr.src_addr));
if (memcmp(&p_rx_pkt->rfc1042_hdr,
rfc1042_eth_hdr, sizeof(rfc1042_eth_hdr)) == 0) {
/*
* Replace the 803 header and rfc1042 header (llc/snap) with an
* EthernetII header, keep the src/dst and snap_type (ethertype)
*
* The firmware only passes up SNAP frames converting
* all RX Data from 802.11 to 802.2/LLC/SNAP frames.
*
* To create the Ethernet II, just move the src, dst address right
* before the snap_type.
*/
p_ethhdr = (struct ethhdr *)
((u8 *) & p_rx_pkt->eth803_hdr
+ sizeof(p_rx_pkt->eth803_hdr) + sizeof(p_rx_pkt->rfc1042_hdr)
- sizeof(p_rx_pkt->eth803_hdr.dest_addr)
- sizeof(p_rx_pkt->eth803_hdr.src_addr)
- sizeof(p_rx_pkt->rfc1042_hdr.snap_type));
memcpy(p_ethhdr->h_source, p_rx_pkt->eth803_hdr.src_addr,
sizeof(p_ethhdr->h_source));
memcpy(p_ethhdr->h_dest, p_rx_pkt->eth803_hdr.dest_addr,
sizeof(p_ethhdr->h_dest));
/* Chop off the rxpd + the excess memory from the 802.2/llc/snap header
* that was removed
*/
hdrchop = (u8 *)p_ethhdr - (u8 *)p_rx_pd;
} else {
lbs_deb_hex(LBS_DEB_RX, "RX Data: LLC/SNAP",
(u8 *) & p_rx_pkt->rfc1042_hdr,
sizeof(p_rx_pkt->rfc1042_hdr));
/* Chop off the rxpd */
hdrchop = (u8 *)&p_rx_pkt->eth803_hdr - (u8 *)p_rx_pd;
}
/* Chop off the leading header bytes so the skb points to the start of
* either the reconstructed EthII frame or the 802.2/llc/snap frame
*/
skb_pull(skb, hdrchop);
/* Take the data rate from the rxpd structure
* only if the rate is auto
*/
if (priv->enablehwauto)
priv->cur_rate = lbs_fw_index_to_data_rate(p_rx_pd->rx_rate);
lbs_compute_rssi(priv, p_rx_pd);
lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
dev->stats.rx_bytes += skb->len;
dev->stats.rx_packets++;
skb->protocol = eth_type_trans(skb, dev);
if (in_interrupt())
netif_rx(skb);
else
netif_rx_ni(skb);
ret = 0;
done:
lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
return ret;
}
EXPORT_SYMBOL_GPL(lbs_process_rxed_packet);
/**
* @brief This function converts Tx/Rx rates from the Marvell WLAN format
* (see Table 2 in Section 3.1) to IEEE80211_RADIOTAP_RATE units (500 Kb/s)
*
* @param rate Input rate
* @return Output Rate (0 if invalid)
*/
static u8 convert_mv_rate_to_radiotap(u8 rate)
{
switch (rate) {
case 0: /* 1 Mbps */
return 2;
case 1: /* 2 Mbps */
return 4;
case 2: /* 5.5 Mbps */
return 11;
case 3: /* 11 Mbps */
return 22;
/* case 4: reserved */
case 5: /* 6 Mbps */
return 12;
case 6: /* 9 Mbps */
return 18;
case 7: /* 12 Mbps */
return 24;
case 8: /* 18 Mbps */
return 36;
case 9: /* 24 Mbps */
return 48;
case 10: /* 36 Mbps */
return 72;
case 11: /* 48 Mbps */
return 96;
case 12: /* 54 Mbps */
return 108;
}
lbs_pr_alert("Invalid Marvell WLAN rate %i\n", rate);
return 0;
}
/**
* @brief This function processes a received 802.11 packet and forwards it
* to kernel/upper layer
*
* @param priv A pointer to struct lbs_private
* @param skb A pointer to skb which includes the received packet
* @return 0 or -1
*/
static int process_rxed_802_11_packet(struct lbs_private *priv,
struct sk_buff *skb)
{
int ret = 0;
struct net_device *dev = priv->dev;
struct rx80211packethdr *p_rx_pkt;
struct rxpd *prxpd;
struct rx_radiotap_hdr radiotap_hdr;
struct rx_radiotap_hdr *pradiotap_hdr;
lbs_deb_enter(LBS_DEB_RX);
p_rx_pkt = (struct rx80211packethdr *) skb->data;
prxpd = &p_rx_pkt->rx_pd;
// lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data, min(skb->len, 100));
if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
lbs_deb_rx("rx err: frame received with bad length\n");
dev->stats.rx_length_errors++;
ret = -EINVAL;
kfree_skb(skb);
goto done;
}
lbs_deb_rx("rx data: skb->len-sizeof(RxPd) = %d-%zd = %zd\n",
skb->len, sizeof(struct rxpd), skb->len - sizeof(struct rxpd));
/* create the exported radio header */
/* radiotap header */
radiotap_hdr.hdr.it_version = 0;
/* XXX must check this value for pad */
radiotap_hdr.hdr.it_pad = 0;
radiotap_hdr.hdr.it_len = cpu_to_le16 (sizeof(struct rx_radiotap_hdr));
radiotap_hdr.hdr.it_present = cpu_to_le32 (RX_RADIOTAP_PRESENT);
radiotap_hdr.rate = convert_mv_rate_to_radiotap(prxpd->rx_rate);
/* XXX must check no carryout */
radiotap_hdr.antsignal = prxpd->snr + prxpd->nf;
/* chop the rxpd */
skb_pull(skb, sizeof(struct rxpd));
/* add space for the new radio header */
if ((skb_headroom(skb) < sizeof(struct rx_radiotap_hdr)) &&
pskb_expand_head(skb, sizeof(struct rx_radiotap_hdr), 0, GFP_ATOMIC)) {
lbs_pr_alert("%s: couldn't pskb_expand_head\n", __func__);
ret = -ENOMEM;
kfree_skb(skb);
goto done;
}
pradiotap_hdr = (void *)skb_push(skb, sizeof(struct rx_radiotap_hdr));
memcpy(pradiotap_hdr, &radiotap_hdr, sizeof(struct rx_radiotap_hdr));
/* Take the data rate from the rxpd structure
* only if the rate is auto
*/
if (priv->enablehwauto)
priv->cur_rate = lbs_fw_index_to_data_rate(prxpd->rx_rate);
lbs_compute_rssi(priv, prxpd);
lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
dev->stats.rx_bytes += skb->len;
dev->stats.rx_packets++;
skb->protocol = eth_type_trans(skb, priv->rtap_net_dev);
netif_rx(skb);
ret = 0;
done:
lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
return ret;
}
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