scan.c

linux内核源码

int libertas_send_specific_ssid_scan(wlan_private * priv,
			u8 *ssid, u8 ssid_len, u8 clear_ssid)
{
	wlan_adapter *adapter = priv->adapter;
	struct wlan_ioctl_user_scan_cfg scancfg;
	int ret = 0;

	lbs_deb_enter_args(LBS_DEB_SCAN, "SSID '%s', clear %d",
		escape_essid(ssid, ssid_len), clear_ssid);

	if (!ssid_len)
		goto out;

	memset(&scancfg, 0x00, sizeof(scancfg));
	memcpy(scancfg.ssid, ssid, ssid_len);
	scancfg.ssid_len = ssid_len;
	scancfg.clear_ssid = clear_ssid;

	wlan_scan_networks(priv, &scancfg, 1);
	if (adapter->surpriseremoved) {
		ret = -1;
		goto out;
	}
	wait_event_interruptible(adapter->cmd_pending, !adapter->nr_cmd_pending);

out:
	lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
	return ret;
}




/*********************************************************************/
/*                                                                   */
/*  Support for Wireless Extensions                                  */
/*                                                                   */
/*********************************************************************/

#define MAX_CUSTOM_LEN 64

static inline char *libertas_translate_scan(wlan_private *priv,
					char *start, char *stop,
					struct bss_descriptor *bss)
{
	wlan_adapter *adapter = priv->adapter;
	struct chan_freq_power *cfp;
	char *current_val;	/* For rates */
	struct iw_event iwe;	/* Temporary buffer */
	int j;
#define PERFECT_RSSI ((u8)50)
#define WORST_RSSI   ((u8)0)
#define RSSI_DIFF    ((u8)(PERFECT_RSSI - WORST_RSSI))
	u8 rssi;

	lbs_deb_enter(LBS_DEB_SCAN);

	cfp = libertas_find_cfp_by_band_and_channel(adapter, 0, bss->channel);
	if (!cfp) {
		lbs_deb_scan("Invalid channel number %d\n", bss->channel);
		start = NULL;
		goto out;
	}

	/* First entry *MUST* be the AP BSSID */
	iwe.cmd = SIOCGIWAP;
	iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
	memcpy(iwe.u.ap_addr.sa_data, &bss->bssid, ETH_ALEN);
	start = iwe_stream_add_event(start, stop, &iwe, IW_EV_ADDR_LEN);

	/* SSID */
	iwe.cmd = SIOCGIWESSID;
	iwe.u.data.flags = 1;
	iwe.u.data.length = min((u32) bss->ssid_len, (u32) IW_ESSID_MAX_SIZE);
	start = iwe_stream_add_point(start, stop, &iwe, bss->ssid);

	/* Mode */
	iwe.cmd = SIOCGIWMODE;
	iwe.u.mode = bss->mode;
	start = iwe_stream_add_event(start, stop, &iwe, IW_EV_UINT_LEN);

	/* Frequency */
	iwe.cmd = SIOCGIWFREQ;
	iwe.u.freq.m = (long)cfp->freq * 100000;
	iwe.u.freq.e = 1;
	start = iwe_stream_add_event(start, stop, &iwe, IW_EV_FREQ_LEN);

	/* Add quality statistics */
	iwe.cmd = IWEVQUAL;
	iwe.u.qual.updated = IW_QUAL_ALL_UPDATED;
	iwe.u.qual.level = SCAN_RSSI(bss->rssi);

	rssi = iwe.u.qual.level - MRVDRV_NF_DEFAULT_SCAN_VALUE;
	iwe.u.qual.qual =
	    (100 * RSSI_DIFF * RSSI_DIFF - (PERFECT_RSSI - rssi) *
	     (15 * (RSSI_DIFF) + 62 * (PERFECT_RSSI - rssi))) /
	    (RSSI_DIFF * RSSI_DIFF);
	if (iwe.u.qual.qual > 100)
		iwe.u.qual.qual = 100;

	if (adapter->NF[TYPE_BEACON][TYPE_NOAVG] == 0) {
		iwe.u.qual.noise = MRVDRV_NF_DEFAULT_SCAN_VALUE;
	} else {
		iwe.u.qual.noise =
		    CAL_NF(adapter->NF[TYPE_BEACON][TYPE_NOAVG]);
	}

	/* Locally created ad-hoc BSSs won't have beacons if this is the
	 * only station in the adhoc network; so get signal strength
	 * from receive statistics.
	 */
	if ((adapter->mode == IW_MODE_ADHOC)
	    && adapter->adhoccreate
	    && !libertas_ssid_cmp(adapter->curbssparams.ssid,
	                          adapter->curbssparams.ssid_len,
	                          bss->ssid, bss->ssid_len)) {
		int snr, nf;
		snr = adapter->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE;
		nf = adapter->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE;
		iwe.u.qual.level = CAL_RSSI(snr, nf);
	}
	start = iwe_stream_add_event(start, stop, &iwe, IW_EV_QUAL_LEN);

	/* Add encryption capability */
	iwe.cmd = SIOCGIWENCODE;
	if (bss->capability & WLAN_CAPABILITY_PRIVACY) {
		iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
	} else {
		iwe.u.data.flags = IW_ENCODE_DISABLED;
	}
	iwe.u.data.length = 0;
	start = iwe_stream_add_point(start, stop, &iwe, bss->ssid);

	current_val = start + IW_EV_LCP_LEN;

	iwe.cmd = SIOCGIWRATE;
	iwe.u.bitrate.fixed = 0;
	iwe.u.bitrate.disabled = 0;
	iwe.u.bitrate.value = 0;

	for (j = 0; bss->rates[j] && (j < sizeof(bss->rates)); j++) {
		/* Bit rate given in 500 kb/s units */
		iwe.u.bitrate.value = bss->rates[j] * 500000;
		current_val = iwe_stream_add_value(start, current_val,
					 stop, &iwe, IW_EV_PARAM_LEN);
	}
	if ((bss->mode == IW_MODE_ADHOC)
	    && !libertas_ssid_cmp(adapter->curbssparams.ssid,
	                          adapter->curbssparams.ssid_len,
	                          bss->ssid, bss->ssid_len)
	    && adapter->adhoccreate) {
		iwe.u.bitrate.value = 22 * 500000;
		current_val = iwe_stream_add_value(start, current_val,
					 stop, &iwe, IW_EV_PARAM_LEN);
	}
	/* Check if we added any event */
	if((current_val - start) > IW_EV_LCP_LEN)
		start = current_val;

	memset(&iwe, 0, sizeof(iwe));
	if (bss->wpa_ie_len) {
		char buf[MAX_WPA_IE_LEN];
		memcpy(buf, bss->wpa_ie, bss->wpa_ie_len);
		iwe.cmd = IWEVGENIE;
		iwe.u.data.length = bss->wpa_ie_len;
		start = iwe_stream_add_point(start, stop, &iwe, buf);
	}

	memset(&iwe, 0, sizeof(iwe));
	if (bss->rsn_ie_len) {
		char buf[MAX_WPA_IE_LEN];
		memcpy(buf, bss->rsn_ie, bss->rsn_ie_len);
		iwe.cmd = IWEVGENIE;
		iwe.u.data.length = bss->rsn_ie_len;
		start = iwe_stream_add_point(start, stop, &iwe, buf);
	}

	if (bss->mesh) {
		char custom[MAX_CUSTOM_LEN];
		char *p = custom;

		iwe.cmd = IWEVCUSTOM;
		p += snprintf(p, MAX_CUSTOM_LEN - (p - custom),
		              "mesh-type: olpc");
		iwe.u.data.length = p - custom;
		if (iwe.u.data.length)
			start = iwe_stream_add_point(start, stop, &iwe, custom);
	}

out:
	lbs_deb_leave_args(LBS_DEB_SCAN, "start %p", start);
	return start;
}

/**
 *  @brief  Handle Retrieve scan table ioctl
 *
 *  @param dev          A pointer to net_device structure
 *  @param info         A pointer to iw_request_info structure
 *  @param dwrq         A pointer to iw_point structure
 *  @param extra        A pointer to extra data buf
 *
 *  @return             0 --success, otherwise fail
 */
int libertas_get_scan(struct net_device *dev, struct iw_request_info *info,
		  struct iw_point *dwrq, char *extra)
{
#define SCAN_ITEM_SIZE 128
	wlan_private *priv = dev->priv;
	wlan_adapter *adapter = priv->adapter;
	int err = 0;
	char *ev = extra;
	char *stop = ev + dwrq->length;
	struct bss_descriptor * iter_bss;
	struct bss_descriptor * safe;

	lbs_deb_enter(LBS_DEB_SCAN);

	/* Update RSSI if current BSS is a locally created ad-hoc BSS */
	if ((adapter->mode == IW_MODE_ADHOC) && adapter->adhoccreate) {
		libertas_prepare_and_send_command(priv, CMD_802_11_RSSI, 0,
					CMD_OPTION_WAITFORRSP, 0, NULL);
	}

	mutex_lock(&adapter->lock);
	list_for_each_entry_safe (iter_bss, safe, &adapter->network_list, list) {
		char * next_ev;
		unsigned long stale_time;

		if (stop - ev < SCAN_ITEM_SIZE) {
			err = -E2BIG;
			break;
		}

		/* For mesh device, list only mesh networks */
		if (dev == priv->mesh_dev && !iter_bss->mesh)
			continue;

		/* Prune old an old scan result */
		stale_time = iter_bss->last_scanned + DEFAULT_MAX_SCAN_AGE;
		if (time_after(jiffies, stale_time)) {
			list_move_tail (&iter_bss->list,
			                &adapter->network_free_list);
			clear_bss_descriptor(iter_bss);
			continue;
		}

		/* Translate to WE format this entry */
		next_ev = libertas_translate_scan(priv, ev, stop, iter_bss);
		if (next_ev == NULL)
			continue;
		ev = next_ev;
	}
	mutex_unlock(&adapter->lock);

	dwrq->length = (ev - extra);
	dwrq->flags = 0;

	lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", err);
	return err;
}




/*********************************************************************/
/*                                                                   */
/*  Command execution                                                */
/*                                                                   */
/*********************************************************************/


/**
 *  @brief Prepare a scan command to be sent to the firmware
 *
 *  Called from libertas_prepare_and_send_command() in cmd.c
 *
 *  Sends a fixed lenght data part (specifying the BSS type and BSSID filters)
 *  as well as a variable number/length of TLVs to the firmware.
 *
 *  @param priv       A pointer to wlan_private structure
 *  @param cmd        A pointer to cmd_ds_command structure to be sent to
 *                    firmware with the cmd_DS_801_11_SCAN structure
 *  @param pdata_buf  Void pointer cast of a wlan_scan_cmd_config struct used
 *                    to set the fields/TLVs for the command sent to firmware
 *
 *  @return           0 or -1
 */
int libertas_cmd_80211_scan(wlan_private * priv,
			 struct cmd_ds_command *cmd, void *pdata_buf)
{
	struct cmd_ds_802_11_scan *pscan = &cmd->params.scan;
	struct wlan_scan_cmd_config *pscancfg = pdata_buf;

	lbs_deb_enter(LBS_DEB_SCAN);

	/* Set fixed field variables in scan command */
	pscan->bsstype = pscancfg->bsstype;
	memcpy(pscan->bssid, pscancfg->bssid, ETH_ALEN);
	memcpy(pscan->tlvbuffer, pscancfg->tlvbuffer, pscancfg->tlvbufferlen);

	cmd->command = cpu_to_le16(CMD_802_11_SCAN);

	/* size is equal to the sizeof(fixed portions) + the TLV len + header */
	cmd->size = cpu_to_le16(sizeof(pscan->bsstype) + ETH_ALEN
				+ pscancfg->tlvbufferlen + S_DS_GEN);

	lbs_deb_scan("SCAN_CMD: command 0x%04x, size %d, seqnum %d\n",
		     le16_to_cpu(cmd->command), le16_to_cpu(cmd->size),
		     le16_to_cpu(cmd->seqnum));

	lbs_deb_leave(LBS_DEB_SCAN);
	return 0;
}

static inline int is_same_network(struct bss_descriptor *src,
				  struct bss_descriptor *dst)
{
	/* A network is only a duplicate if the channel, BSSID, and ESSID
	 * all match.  We treat all <hidden> with the same BSSID and channel
	 * as one network */
	return ((src->ssid_len == dst->ssid_len) &&
		(src->channel == dst->channel) &&
		!compare_ether_addr(src->bssid, dst->bssid) &&
		!memcmp(src->ssid, dst->ssid, src->ssid_len));
}

/**
 *  @brief This function handles the command response of scan
 *
 *  Called from handle_cmd_response() in cmdrespc.
 *
 *   The response buffer for the scan command has the following
 *      memory layout:
 *
 *     .-----------------------------------------------------------.
 *     |  header (4 * sizeof(u16)):  Standard command response hdr |
 *     .-----------------------------------------------------------.
 *     |  bufsize (u16) : sizeof the BSS Description data          |
 *     .-----------------------------------------------------------.
 *     |  NumOfSet (u8) : Number of BSS Descs returned             |
 *     .-----------------------------------------------------------.
 *     |  BSSDescription data (variable, size given in bufsize)    |
 *     .-----------------------------------------------------------.
 *     |  TLV data (variable, size calculated using header->size,  |
 *     |            bufsize and sizeof the fixed fields above)     |
 *     .-----------------------------------------------------------.
 *
 *  @param priv    A pointer to wlan_private structure
 *  @param resp    A pointer to cmd_ds_command
 *
 *  @return        0 or -1
 */
int libertas_ret_80211_scan(wlan_private * priv, struct cmd_ds_command *resp)
{
	wlan_adapter *adapter = priv->adapter;
	struct cmd_ds_802_11_scan_rsp *pscan;
	struct bss_descriptor * iter_bss;
	struct bss_descriptor * safe;
	u8 *pbssinfo;
	u16 scanrespsize;
	int bytesleft;
	int idx;
	int tlvbufsize;
	int ret;

	lbs_deb_enter(LBS_DEB_SCAN);

	/* Prune old entries from scan table */
	list_for_each_entry_safe (iter_bss, safe, &adapter->network_list, list) {
		unsigned long stale_time = iter_bss->last_scanned + DEFAULT_MAX_SCAN_AGE;
		if (time_before(jiffies, stale_time))
			continue;
		list_move_tail (&iter_bss->list, &adapter->network_free_list);
		clear_bss_descriptor(iter_bss);
	}

	pscan = &resp->params.scanresp;

	if (pscan->nr_sets > MAX_NETWORK_COUNT) {
		lbs_deb_scan(
		       "SCAN_RESP: too many scan results (%d, max %d)!!\n",
		       pscan->nr_sets, MAX_NETWORK_COUNT);
		ret = -1;
		goto done;
	}

	bytesleft = le16_to_cpu(get_unaligned((u16*)&pscan->bssdescriptsize));
	lbs_deb_scan("SCAN_RESP: bssdescriptsize %d\n", bytesleft);

	scanrespsize = le16_to_cpu(get_unaligned((u16*)&resp->size));
	lbs_deb_scan("SCAN_RESP: returned %d AP before parsing\n",
	       pscan->nr_sets);

	pbssinfo = pscan->bssdesc_and_tlvbuffer;

	/* The size of the TLV buffer is equal to the entire command response
	 *   size (scanrespsize) minus the fixed fields (sizeof()'s), the
	 *   BSS Descriptions (bssdescriptsize as bytesLef) and the command
	 *   response header (S_DS_GEN)
	 */
	tlvbufsize = scanrespsize - (bytesleft + sizeof(pscan->bssdescriptsize)
				     + sizeof(pscan->nr_sets)
				     + S_DS_GEN);

	/*
	 *  Process each scan response returned (pscan->nr_sets).  Save
	 *    the information in the newbssentry and then insert into the
	 *    driver scan table either as an update to an existing entry
	 *    or as an addition at the end of the table
	 */
	for (idx = 0; idx < pscan->nr_sets && bytesleft; idx++) {
		struct bss_descriptor new;
		struct bss_descriptor * found = NULL;
		struct bss_descriptor * oldest = NULL;
		DECLARE_MAC_BUF(mac);

		/* Process the data fields and IEs returned for this BSS */
		memset(&new, 0, sizeof (struct bss_descriptor));
		if (libertas_process_bss(&new, &pbssinfo, &bytesleft) != 0) {
			/* error parsing the scan response, skipped */
			lbs_deb_scan("SCAN_RESP: process_bss returned ERROR\n");
			continue;
		}

		/* Try to find this bss in the scan table */
		list_for_each_entry (iter_bss, &adapter->network_list, list) {
			if (is_same_network(iter_bss, &new)) {
				found = iter_bss;
				break;
			}

			if ((oldest == NULL) ||
			    (iter_bss->last_scanned < oldest->last_scanned))
				oldest = iter_bss;
		}

		if (found) {
			/* found, clear it */
			clear_bss_descriptor(found);
		} else if (!list_empty(&adapter->network_free_list)) {
			/* Pull one from the free list */
			found = list_entry(adapter->network_free_list.next,
					   struct bss_descriptor, list);
			list_move_tail(&found->list, &adapter->network_list);
		} else if (oldest) {
			/* If there are no more slots, expire the oldest */
			found = oldest;
			clear_bss_descriptor(found);
			list_move_tail(&found->list, &adapter->network_list);
		} else {
			continue;
		}

		lbs_deb_scan("SCAN_RESP: BSSID = %s\n",
			     print_mac(mac, new.bssid));

		/* Copy the locally created newbssentry to the scan table */
		memcpy(found, &new, offsetof(struct bss_descriptor, list));
	}

	ret = 0;

done:
	lbs_deb_leave_args(LBS_DEB_SCAN, "ret %d", ret);
	return ret;
}