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linux/drivers/net/wireless/libertas/rx.c
Luis Carlos Cobo 965f8bbc6c [PATCH] libertas: monitor mode support for OLPC firmware 
Driver support for the monitor mode support that will be available in the next
OLPC 'bleeding edge' Marvell firmware release (most likely, 5.110.16.p2).

To activate monitor mode,

echo mode > /sys/class/net/{ethX,mshX}/device/libertas_rtap

where mode is the hex mask that specifies which frames to sniff (in short, 0x1
for data, 0x2 for all management but beacons, 0x4 for beacons). Any non zero
mode will activate the monitor mode, inhibiting transmission in ethX and mshX
interfaces and routing all the incoming traffic to a new rtapX interface that
will output the packets in 802.11+radiotap headers format.

Signed-off-by: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2007-10-10 16:50:13 -07:00

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/**
* This file contains the handling of RX in wlan driver.
*/
#include <linux/etherdevice.h>
#include <linux/types.h>
#include "hostcmd.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 rxpd rx_pd;
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(wlan_private * priv, struct sk_buff *skb);
/**
* @brief This function computes the avgSNR .
*
* @param priv A pointer to wlan_private structure
* @return avgSNR
*/
static u8 wlan_getavgsnr(wlan_private * priv)
{
u8 i;
u16 temp = 0;
wlan_adapter *adapter = priv->adapter;
if (adapter->numSNRNF == 0)
return 0;
for (i = 0; i < adapter->numSNRNF; i++)
temp += adapter->rawSNR[i];
return (u8) (temp / adapter->numSNRNF);
}
/**
* @brief This function computes the AvgNF
*
* @param priv A pointer to wlan_private structure
* @return AvgNF
*/
static u8 wlan_getavgnf(wlan_private * priv)
{
u8 i;
u16 temp = 0;
wlan_adapter *adapter = priv->adapter;
if (adapter->numSNRNF == 0)
return 0;
for (i = 0; i < adapter->numSNRNF; i++)
temp += adapter->rawNF[i];
return (u8) (temp / adapter->numSNRNF);
}
/**
* @brief This function save the raw SNR/NF to our internel buffer
*
* @param priv A pointer to wlan_private structure
* @param prxpd A pointer to rxpd structure of received packet
* @return n/a
*/
static void wlan_save_rawSNRNF(wlan_private * priv, struct rxpd *p_rx_pd)
{
wlan_adapter *adapter = priv->adapter;
if (adapter->numSNRNF < DEFAULT_DATA_AVG_FACTOR)
adapter->numSNRNF++;
adapter->rawSNR[adapter->nextSNRNF] = p_rx_pd->snr;
adapter->rawNF[adapter->nextSNRNF] = p_rx_pd->nf;
adapter->nextSNRNF++;
if (adapter->nextSNRNF >= DEFAULT_DATA_AVG_FACTOR)
adapter->nextSNRNF = 0;
return;
}
/**
* @brief This function computes the RSSI in received packet.
*
* @param priv A pointer to wlan_private structure
* @param prxpd A pointer to rxpd structure of received packet
* @return n/a
*/
static void wlan_compute_rssi(wlan_private * priv, struct rxpd *p_rx_pd)
{
wlan_adapter *adapter = priv->adapter;
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",
adapter->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
adapter->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
adapter->SNR[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->snr;
adapter->NF[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->nf;
wlan_save_rawSNRNF(priv, p_rx_pd);
adapter->SNR[TYPE_RXPD][TYPE_AVG] = wlan_getavgsnr(priv) * AVG_SCALE;
adapter->NF[TYPE_RXPD][TYPE_AVG] = wlan_getavgnf(priv) * AVG_SCALE;
lbs_deb_rx("after computing SNR: SNR-avg = %d, NF-avg = %d\n",
adapter->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
adapter->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
adapter->RSSI[TYPE_RXPD][TYPE_NOAVG] =
CAL_RSSI(adapter->SNR[TYPE_RXPD][TYPE_NOAVG],
adapter->NF[TYPE_RXPD][TYPE_NOAVG]);
adapter->RSSI[TYPE_RXPD][TYPE_AVG] =
CAL_RSSI(adapter->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
adapter->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
lbs_deb_leave(LBS_DEB_RX);
}
void libertas_upload_rx_packet(wlan_private * priv, struct sk_buff *skb)
{
lbs_deb_rx("skb->data %p\n", skb->data);
if (priv->adapter->monitormode != WLAN_MONITOR_OFF) {
skb->protocol = eth_type_trans(skb, priv->rtap_net_dev);
} else {
if (priv->mesh_dev && IS_MESH_FRAME(skb))
skb->protocol = eth_type_trans(skb, priv->mesh_dev);
else
skb->protocol = eth_type_trans(skb, priv->dev);
}
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_rx(skb);
}
/**
* @brief This function processes received packet and forwards it
* to kernel/upper layer
*
* @param priv A pointer to wlan_private
* @param skb A pointer to skb which includes the received packet
* @return 0 or -1
*/
int libertas_process_rxed_packet(wlan_private * priv, struct sk_buff *skb)
{
wlan_adapter *adapter = priv->adapter;
int ret = 0;
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);
if (priv->adapter->monitormode != WLAN_MONITOR_OFF)
return process_rxed_802_11_packet(priv, skb);
p_rx_pkt = (struct rxpackethdr *) skb->data;
p_rx_pd = &p_rx_pkt->rx_pd;
if (p_rx_pd->rx_control & RxPD_MESH_FRAME)
SET_MESH_FRAME(skb);
else
UNSET_MESH_FRAME(skb);
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");
priv->stats.rx_length_errors++;
ret = 0;
goto done;
}
/*
* Check rxpd status and update 802.3 stat,
*/
if (!(p_rx_pd->status & cpu_to_le16(MRVDRV_RXPD_STATUS_OK))) {
lbs_deb_rx("rx err: frame received with bad status\n");
lbs_pr_alert("rxpd not ok\n");
priv->stats.rx_errors++;
ret = 0;
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));
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_pkt;
} 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_pkt;
}
/* 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 (adapter->auto_rate)
adapter->cur_rate = libertas_fw_index_to_data_rate(p_rx_pd->rx_rate);
wlan_compute_rssi(priv, p_rx_pd);
lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
priv->stats.rx_bytes += skb->len;
priv->stats.rx_packets++;
libertas_upload_rx_packet(priv, skb);
ret = 0;
done:
lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
return ret;
}
EXPORT_SYMBOL_GPL(libertas_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 wlan_private
* @param skb A pointer to skb which includes the received packet
* @return 0 or -1
*/
static int process_rxed_802_11_packet(wlan_private * priv, struct sk_buff *skb)
{
wlan_adapter *adapter = priv->adapter;
int ret = 0;
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 wit bad length\n");
priv->stats.rx_length_errors++;
ret = 0;
goto done;
}
/*
* Check rxpd status and update 802.3 stat,
*/
if (!(prxpd->status & cpu_to_le16(MRVDRV_RXPD_STATUS_OK))) {
//lbs_deb_rx("rx err: frame received with bad status\n");
priv->stats.rx_errors++;
}
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 */
if(priv->adapter->monitormode == WLAN_MONITOR_OFF) {
/* no radio header */
/* chop the rxpd */
skb_pull(skb, sizeof(struct rxpd));
}
else {
/* 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 = sizeof(struct rx_radiotap_hdr);
radiotap_hdr.hdr.it_present = RX_RADIOTAP_PRESENT;
/* unknown values */
radiotap_hdr.flags = 0;
radiotap_hdr.chan_freq = 0;
radiotap_hdr.chan_flags = 0;
radiotap_hdr.antenna = 0;
/* known values */
radiotap_hdr.rate = convert_mv_rate_to_radiotap(prxpd->rx_rate);
/* XXX must check no carryout */
radiotap_hdr.antsignal = prxpd->snr + prxpd->nf;
radiotap_hdr.rx_flags = 0;
if (!(prxpd->status & cpu_to_le16(MRVDRV_RXPD_STATUS_OK)))
radiotap_hdr.rx_flags |= IEEE80211_RADIOTAP_F_RX_BADFCS;
//memset(radiotap_hdr.pad, 0x11, IEEE80211_RADIOTAP_HDRLEN - 18);
/* 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__);
}
pradiotap_hdr =
(struct rx_radiotap_hdr *)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 (adapter->auto_rate)
adapter->cur_rate = libertas_fw_index_to_data_rate(prxpd->rx_rate);
wlan_compute_rssi(priv, prxpd);
lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
priv->stats.rx_bytes += skb->len;
priv->stats.rx_packets++;
libertas_upload_rx_packet(priv, skb);
ret = 0;
done:
lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
return ret;
}
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