ieee80211_sta.c

linux 内核源代码

/*
 * BSS client mode implementation
 * Copyright 2003, Jouni Malinen <[e-mail]>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <[e-mail]>
 * Copyright 2007, Michael Wu <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/* TODO:
 * order BSS list by RSSI(?) ("quality of AP")
 * scan result table filtering (by capability (privacy, IBSS/BSS, WPA/RSN IE,
 *    SSID)
 */
#include <linux/delay.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/wireless.h>
#include <linux/random.h>
#include <linux/etherdevice.h>
#include <net/iw_handler.h>
#include <asm/types.h>

#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "ieee80211_rate.h"
#include "ieee80211_led.h"

#define IEEE80211_AUTH_TIMEOUT (HZ / 5)
#define IEEE80211_AUTH_MAX_TRIES 3
#define IEEE80211_ASSOC_TIMEOUT (HZ / 5)
#define IEEE80211_ASSOC_MAX_TRIES 3
#define IEEE80211_MONITORING_INTERVAL (2 * HZ)
#define IEEE80211_PROBE_INTERVAL (60 * HZ)
#define IEEE80211_RETRY_AUTH_INTERVAL (1 * HZ)
#define IEEE80211_SCAN_INTERVAL (2 * HZ)
#define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
#define IEEE80211_IBSS_JOIN_TIMEOUT (20 * HZ)

#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
#define IEEE80211_SCAN_RESULT_EXPIRE (10 * HZ)
#define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
#define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)

#define IEEE80211_IBSS_MAX_STA_ENTRIES 128


#define IEEE80211_FC(type, stype) cpu_to_le16(type | stype)

#define ERP_INFO_USE_PROTECTION BIT(1)

static void ieee80211_send_probe_req(struct net_device *dev, u8 *dst,
				     u8 *ssid, size_t ssid_len);
static struct ieee80211_sta_bss *
ieee80211_rx_bss_get(struct net_device *dev, u8 *bssid, int channel,
		     u8 *ssid, u8 ssid_len);
static void ieee80211_rx_bss_put(struct net_device *dev,
				 struct ieee80211_sta_bss *bss);
static int ieee80211_sta_find_ibss(struct net_device *dev,
				   struct ieee80211_if_sta *ifsta);
static int ieee80211_sta_wep_configured(struct net_device *dev);
static int ieee80211_sta_start_scan(struct net_device *dev,
				    u8 *ssid, size_t ssid_len);
static int ieee80211_sta_config_auth(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta);


/* Parsed Information Elements */
struct ieee802_11_elems {
	/* pointers to IEs */
	u8 *ssid;
	u8 *supp_rates;
	u8 *fh_params;
	u8 *ds_params;
	u8 *cf_params;
	u8 *tim;
	u8 *ibss_params;
	u8 *challenge;
	u8 *wpa;
	u8 *rsn;
	u8 *erp_info;
	u8 *ext_supp_rates;
	u8 *wmm_info;
	u8 *wmm_param;

	/* length of them, respectively */
	u8 ssid_len;
	u8 supp_rates_len;
	u8 fh_params_len;
	u8 ds_params_len;
	u8 cf_params_len;
	u8 tim_len;
	u8 ibss_params_len;
	u8 challenge_len;
	u8 wpa_len;
	u8 rsn_len;
	u8 erp_info_len;
	u8 ext_supp_rates_len;
	u8 wmm_info_len;
	u8 wmm_param_len;
};

static void ieee802_11_parse_elems(u8 *start, size_t len,
				   struct ieee802_11_elems *elems)
{
	size_t left = len;
	u8 *pos = start;

	memset(elems, 0, sizeof(*elems));

	while (left >= 2) {
		u8 id, elen;

		id = *pos++;
		elen = *pos++;
		left -= 2;

		if (elen > left)
			return;

		switch (id) {
		case WLAN_EID_SSID:
			elems->ssid = pos;
			elems->ssid_len = elen;
			break;
		case WLAN_EID_SUPP_RATES:
			elems->supp_rates = pos;
			elems->supp_rates_len = elen;
			break;
		case WLAN_EID_FH_PARAMS:
			elems->fh_params = pos;
			elems->fh_params_len = elen;
			break;
		case WLAN_EID_DS_PARAMS:
			elems->ds_params = pos;
			elems->ds_params_len = elen;
			break;
		case WLAN_EID_CF_PARAMS:
			elems->cf_params = pos;
			elems->cf_params_len = elen;
			break;
		case WLAN_EID_TIM:
			elems->tim = pos;
			elems->tim_len = elen;
			break;
		case WLAN_EID_IBSS_PARAMS:
			elems->ibss_params = pos;
			elems->ibss_params_len = elen;
			break;
		case WLAN_EID_CHALLENGE:
			elems->challenge = pos;
			elems->challenge_len = elen;
			break;
		case WLAN_EID_WPA:
			if (elen >= 4 && pos[0] == 0x00 && pos[1] == 0x50 &&
			    pos[2] == 0xf2) {
				/* Microsoft OUI (00:50:F2) */
				if (pos[3] == 1) {
					/* OUI Type 1 - WPA IE */
					elems->wpa = pos;
					elems->wpa_len = elen;
				} else if (elen >= 5 && pos[3] == 2) {
					if (pos[4] == 0) {
						elems->wmm_info = pos;
						elems->wmm_info_len = elen;
					} else if (pos[4] == 1) {
						elems->wmm_param = pos;
						elems->wmm_param_len = elen;
					}
				}
			}
			break;
		case WLAN_EID_RSN:
			elems->rsn = pos;
			elems->rsn_len = elen;
			break;
		case WLAN_EID_ERP_INFO:
			elems->erp_info = pos;
			elems->erp_info_len = elen;
			break;
		case WLAN_EID_EXT_SUPP_RATES:
			elems->ext_supp_rates = pos;
			elems->ext_supp_rates_len = elen;
			break;
		default:
			break;
		}

		left -= elen;
		pos += elen;
	}
}


static int ecw2cw(int ecw)
{
	int cw = 1;
	while (ecw > 0) {
		cw <<= 1;
		ecw--;
	}
	return cw - 1;
}

static void ieee80211_sta_wmm_params(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta,
				     u8 *wmm_param, size_t wmm_param_len)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_tx_queue_params params;
	size_t left;
	int count;
	u8 *pos;

	if (wmm_param_len < 8 || wmm_param[5] /* version */ != 1)
		return;
	count = wmm_param[6] & 0x0f;
	if (count == ifsta->wmm_last_param_set)
		return;
	ifsta->wmm_last_param_set = count;

	pos = wmm_param + 8;
	left = wmm_param_len - 8;

	memset(&params, 0, sizeof(params));

	if (!local->ops->conf_tx)
		return;

	local->wmm_acm = 0;
	for (; left >= 4; left -= 4, pos += 4) {
		int aci = (pos[0] >> 5) & 0x03;
		int acm = (pos[0] >> 4) & 0x01;
		int queue;

		switch (aci) {
		case 1:
			queue = IEEE80211_TX_QUEUE_DATA3;
			if (acm) {
				local->wmm_acm |= BIT(0) | BIT(3);
			}
			break;
		case 2:
			queue = IEEE80211_TX_QUEUE_DATA1;
			if (acm) {
				local->wmm_acm |= BIT(4) | BIT(5);
			}
			break;
		case 3:
			queue = IEEE80211_TX_QUEUE_DATA0;
			if (acm) {
				local->wmm_acm |= BIT(6) | BIT(7);
			}
			break;
		case 0:
		default:
			queue = IEEE80211_TX_QUEUE_DATA2;
			if (acm) {
				local->wmm_acm |= BIT(1) | BIT(2);
			}
			break;
		}

		params.aifs = pos[0] & 0x0f;
		params.cw_max = ecw2cw((pos[1] & 0xf0) >> 4);
		params.cw_min = ecw2cw(pos[1] & 0x0f);
		/* TXOP is in units of 32 usec; burst_time in 0.1 ms */
		params.burst_time = (pos[2] | (pos[3] << 8)) * 32 / 100;
		printk(KERN_DEBUG "%s: WMM queue=%d aci=%d acm=%d aifs=%d "
		       "cWmin=%d cWmax=%d burst=%d\n",
		       dev->name, queue, aci, acm, params.aifs, params.cw_min,
		       params.cw_max, params.burst_time);
		/* TODO: handle ACM (block TX, fallback to next lowest allowed
		 * AC for now) */
		if (local->ops->conf_tx(local_to_hw(local), queue, &params)) {
			printk(KERN_DEBUG "%s: failed to set TX queue "
			       "parameters for queue %d\n", dev->name, queue);
		}
	}
}


static void ieee80211_handle_erp_ie(struct net_device *dev, u8 erp_value)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	int use_protection = (erp_value & WLAN_ERP_USE_PROTECTION) != 0;
	int preamble_mode = (erp_value & WLAN_ERP_BARKER_PREAMBLE) != 0;
	u8 changes = 0;
	DECLARE_MAC_BUF(mac);

	if (use_protection != !!(sdata->flags & IEEE80211_SDATA_USE_PROTECTION)) {
		if (net_ratelimit()) {
			printk(KERN_DEBUG "%s: CTS protection %s (BSSID="
			       "%s)\n",
			       dev->name,
			       use_protection ? "enabled" : "disabled",
			       print_mac(mac, ifsta->bssid));
		}
		if (use_protection)
			sdata->flags |= IEEE80211_SDATA_USE_PROTECTION;
		else
			sdata->flags &= ~IEEE80211_SDATA_USE_PROTECTION;
		changes |= IEEE80211_ERP_CHANGE_PROTECTION;
	}

	if (preamble_mode != !(sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE)) {
		if (net_ratelimit()) {
			printk(KERN_DEBUG "%s: switched to %s barker preamble"
			       " (BSSID=%s)\n",
			       dev->name,
			       (preamble_mode == WLAN_ERP_PREAMBLE_SHORT) ?
					"short" : "long",
			       print_mac(mac, ifsta->bssid));
		}
		if (preamble_mode)
			sdata->flags &= ~IEEE80211_SDATA_SHORT_PREAMBLE;
		else
			sdata->flags |= IEEE80211_SDATA_SHORT_PREAMBLE;
		changes |= IEEE80211_ERP_CHANGE_PREAMBLE;
	}

	if (changes)
		ieee80211_erp_info_change_notify(dev, changes);
}


static void ieee80211_sta_send_associnfo(struct net_device *dev,
					 struct ieee80211_if_sta *ifsta)
{
	char *buf;
	size_t len;
	int i;
	union iwreq_data wrqu;

	if (!ifsta->assocreq_ies && !ifsta->assocresp_ies)
		return;

	buf = kmalloc(50 + 2 * (ifsta->assocreq_ies_len +
				ifsta->assocresp_ies_len), GFP_KERNEL);
	if (!buf)
		return;

	len = sprintf(buf, "ASSOCINFO(");
	if (ifsta->assocreq_ies) {
		len += sprintf(buf + len, "ReqIEs=");
		for (i = 0; i < ifsta->assocreq_ies_len; i++) {
			len += sprintf(buf + len, "%02x",
				       ifsta->assocreq_ies[i]);
		}
	}
	if (ifsta->assocresp_ies) {
		if (ifsta->assocreq_ies)
			len += sprintf(buf + len, " ");
		len += sprintf(buf + len, "RespIEs=");
		for (i = 0; i < ifsta->assocresp_ies_len; i++) {
			len += sprintf(buf + len, "%02x",
				       ifsta->assocresp_ies[i]);
		}
	}
	len += sprintf(buf + len, ")");

	if (len > IW_CUSTOM_MAX) {
		len = sprintf(buf, "ASSOCRESPIE=");
		for (i = 0; i < ifsta->assocresp_ies_len; i++) {
			len += sprintf(buf + len, "%02x",
				       ifsta->assocresp_ies[i]);
		}
	}

	memset(&wrqu, 0, sizeof(wrqu));
	wrqu.data.length = len;
	wireless_send_event(dev, IWEVCUSTOM, &wrqu, buf);

	kfree(buf);
}


static void ieee80211_set_associated(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta,
				     bool assoc)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	union iwreq_data wrqu;

	if (!!(ifsta->flags & IEEE80211_STA_ASSOCIATED) == assoc)
		return;

	if (assoc) {
		struct ieee80211_sub_if_data *sdata;
		struct ieee80211_sta_bss *bss;

		ifsta->flags |= IEEE80211_STA_ASSOCIATED;

		sdata = IEEE80211_DEV_TO_SUB_IF(dev);
		if (sdata->type != IEEE80211_IF_TYPE_STA)
			return;

		bss = ieee80211_rx_bss_get(dev, ifsta->bssid,
					   local->hw.conf.channel,
					   ifsta->ssid, ifsta->ssid_len);
		if (bss) {
			if (bss->has_erp_value)
				ieee80211_handle_erp_ie(dev, bss->erp_value);
			ieee80211_rx_bss_put(dev, bss);
		}

		netif_carrier_on(dev);
		ifsta->flags |= IEEE80211_STA_PREV_BSSID_SET;
		memcpy(ifsta->prev_bssid, sdata->u.sta.bssid, ETH_ALEN);
		memcpy(wrqu.ap_addr.sa_data, sdata->u.sta.bssid, ETH_ALEN);
		ieee80211_sta_send_associnfo(dev, ifsta);
	} else {
		ifsta->flags &= ~IEEE80211_STA_ASSOCIATED;

		netif_carrier_off(dev);
		ieee80211_reset_erp_info(dev);
		memset(wrqu.ap_addr.sa_data, 0, ETH_ALEN);
	}
	wrqu.ap_addr.sa_family = ARPHRD_ETHER;
	wireless_send_event(dev, SIOCGIWAP, &wrqu, NULL);
	ifsta->last_probe = jiffies;
	ieee80211_led_assoc(local, assoc);
}

static void ieee80211_set_disassoc(struct net_device *dev,
				   struct ieee80211_if_sta *ifsta, int deauth)
{
	if (deauth)
		ifsta->auth_tries = 0;
	ifsta->assoc_tries = 0;
	ieee80211_set_associated(dev, ifsta, 0);
}

static void ieee80211_sta_tx(struct net_device *dev, struct sk_buff *skb,
			     int encrypt)
{
	struct ieee80211_sub_if_data *sdata;
	struct ieee80211_tx_packet_data *pkt_data;

	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	skb->dev = sdata->local->mdev;
	skb_set_mac_header(skb, 0);
	skb_set_network_header(skb, 0);
	skb_set_transport_header(skb, 0);

	pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
	memset(pkt_data, 0, sizeof(struct ieee80211_tx_packet_data));
	pkt_data->ifindex = sdata->dev->ifindex;
	if (!encrypt)
		pkt_data->flags |= IEEE80211_TXPD_DO_NOT_ENCRYPT;

	dev_queue_xmit(skb);
}


static void ieee80211_send_auth(struct net_device *dev,
				struct ieee80211_if_sta *ifsta,
				int transaction, u8 *extra, size_t extra_len,
				int encrypt)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sk_buff *skb;