path: root/net/mac80211/ibss.c

/*
 * IBSS mode implementation
 * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
 *
 * 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.
 */

#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>

#include "ieee80211_i.h"
#include "driver-ops.h"
#include "rate.h"

#define IEEE80211_SCAN_INTERVAL (2 * HZ)
#define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
#define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)

#define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
#define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)

#define IEEE80211_IBSS_MAX_STA_ENTRIES 128


static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
				      const u8 *bssid, const int beacon_int,
				      struct ieee80211_channel *chan,
				      const u32 basic_rates,
				      const u16 capability, u64 tsf)
{
	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
	struct ieee80211_local *local = sdata->local;
	int rates, i;
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;
	u8 *pos;
	struct ieee80211_supported_band *sband;
	struct cfg80211_bss *bss;
	u32 bss_change;
	u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
	enum nl80211_channel_type channel_type;

	lockdep_assert_held(&ifibss->mtx);

	/* Reset own TSF to allow time synchronization work. */
	drv_reset_tsf(local, sdata);

	skb = ifibss->skb;
	RCU_INIT_POINTER(ifibss->presp, NULL);
	synchronize_rcu();
	skb->data = skb->head;
	skb->len = 0;
	skb_reset_tail_pointer(skb);
	skb_reserve(skb, sdata->local->hw.extra_tx_headroom);

	if (!ether_addr_equal(ifibss->bssid, bssid))
		sta_info_flush(sdata->local, sdata);

	/* if merging, indicate to driver that we leave the old IBSS */
	if (sdata->vif.bss_conf.ibss_joined) {
		sdata->vif.bss_conf.ibss_joined = false;
		netif_carrier_off(sdata->dev);
		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IBSS);
	}

	memcpy(ifibss->bssid, bssid, ETH_ALEN);

	sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;

	local->oper_channel = chan;
	channel_type = ifibss->channel_type;
	if (channel_type > NL80211_CHAN_HT20 &&
	    !cfg80211_can_beacon_sec_chan(local->hw.wiphy, chan, channel_type))
		channel_type = NL80211_CHAN_HT20;
	if (!ieee80211_set_channel_type(local, sdata, channel_type)) {
		/* can only fail due to HT40+/- mismatch */
		channel_type = NL80211_CHAN_HT20;
		WARN_ON(!ieee80211_set_channel_type(local, sdata,
						    NL80211_CHAN_HT20));
	}
	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);

	sband = local->hw.wiphy->bands[chan->band];

	/* build supported rates array */
	pos = supp_rates;
	for (i = 0; i < sband->n_bitrates; i++) {
		int rate = sband->bitrates[i].bitrate;
		u8 basic = 0;
		if (basic_rates & BIT(i))
			basic = 0x80;
		*pos++ = basic | (u8) (rate / 5);
	}

	/* Build IBSS probe response */
	mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
	memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
					  IEEE80211_STYPE_PROBE_RESP);
	memset(mgmt->da, 0xff, ETH_ALEN);
	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
	memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
	mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
	mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
	mgmt->u.beacon.capab_info = cpu_to_le16(capability);

	pos = skb_put(skb, 2 + ifibss->ssid_len);
	*pos++ = WLAN_EID_SSID;
	*pos++ = ifibss->ssid_len;
	memcpy(pos, ifibss->ssid, ifibss->ssid_len);

	rates = sband->n_bitrates;
	if (rates > 8)
		rates = 8;
	pos = skb_put(skb, 2 + rates);
	*pos++ = WLAN_EID_SUPP_RATES;
	*pos++ = rates;
	memcpy(pos, supp_rates, rates);

	if (sband->band == IEEE80211_BAND_2GHZ) {
		pos = skb_put(skb, 2 + 1);
		*pos++ = WLAN_EID_DS_PARAMS;
		*pos++ = 1;
		*pos++ = ieee80211_frequency_to_channel(chan->center_freq);
	}

	pos = skb_put(skb, 2 + 2);
	*pos++ = WLAN_EID_IBSS_PARAMS;
	*pos++ = 2;
	/* FIX: set ATIM window based on scan results */
	*pos++ = 0;
	*pos++ = 0;

	if (sband->n_bitrates > 8) {
		rates = sband->n_bitrates - 8;
		pos = skb_put(skb, 2 + rates);
		*pos++ = WLAN_EID_EXT_SUPP_RATES;
		*pos++ = rates;
		memcpy(pos, &supp_rates[8], rates);
	}

	if (ifibss->ie_len)
		memcpy(skb_put(skb, ifibss->ie_len),
		       ifibss->ie, ifibss->ie_len);

	/* add HT capability and information IEs */
	if (channel_type && sband->ht_cap.ht_supported) {
		pos = skb_put(skb, 4 +
				   sizeof(struct ieee80211_ht_cap) +
				   sizeof(