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Commit 9449410f authored by Simon Wunderlich's avatar Simon Wunderlich Committed by Johannes Berg
Browse files

mac80211: send a CSA action frame when changing channel 



IBSS members may not immediately be able to send out their beacon when
performing CSA, therefore also send a CSA action frame.

Signed-off-by: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarMathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent cd7760e6

net/mac80211/ibss.c

+60 −0
Original line number Diff line number Diff line
@@ -428,6 +428,60 @@ static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata, 
				  tsf, false);

}



static int ieee80211_send_action_csa(struct ieee80211_sub_if_data *sdata,

				     struct cfg80211_csa_settings *csa_settings)

{

	struct sk_buff *skb;

	struct ieee80211_mgmt *mgmt;

	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;

	struct ieee80211_local *local = sdata->local;

	int freq;

	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.chan_switch) +

		      sizeof(mgmt->u.action.u.chan_switch);

	u8 *pos;



	skb = dev_alloc_skb(local->tx_headroom + hdr_len +

			    5 +	/* channel switch announcement element */

			    3);	/* secondary channel offset element */

	if (!skb)

		return -1;



	skb_reserve(skb, local->tx_headroom);

	mgmt = (struct ieee80211_mgmt *)skb_put(skb, hdr_len);

	memset(mgmt, 0, hdr_len);

	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |

					  IEEE80211_STYPE_ACTION);



	eth_broadcast_addr(mgmt->da);

	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);

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

	mgmt->u.action.category = WLAN_CATEGORY_SPECTRUM_MGMT;

	mgmt->u.action.u.chan_switch.action_code = WLAN_ACTION_SPCT_CHL_SWITCH;

	pos = skb_put(skb, 5);

	*pos++ = WLAN_EID_CHANNEL_SWITCH;			/* EID */

	*pos++ = 3;						/* IE length */

	*pos++ = csa_settings->block_tx ? 1 : 0;		/* CSA mode */

	freq = csa_settings->chandef.chan->center_freq;

	*pos++ = ieee80211_frequency_to_channel(freq);		/* channel */

	*pos++ = csa_settings->count;				/* count */



	if (csa_settings->chandef.width == NL80211_CHAN_WIDTH_40) {

		enum nl80211_channel_type ch_type;



		skb_put(skb, 3);

		*pos++ = WLAN_EID_SECONDARY_CHANNEL_OFFSET;	/* EID */

		*pos++ = 1;					/* IE length */

		ch_type = cfg80211_get_chandef_type(&csa_settings->chandef);

		if (ch_type == NL80211_CHAN_HT40PLUS)

			*pos++ = IEEE80211_HT_PARAM_CHA_SEC_ABOVE;

		else

			*pos++ = IEEE80211_HT_PARAM_CHA_SEC_BELOW;

	}



	ieee80211_tx_skb(sdata, skb);

	return 0;

}



int ieee80211_ibss_csa_beacon(struct ieee80211_sub_if_data *sdata,

			      struct cfg80211_csa_settings *csa_settings)

{
@@ -480,6 +534,12 @@ int ieee80211_ibss_csa_beacon(struct ieee80211_sub_if_data *sdata, 
	if (old_presp)

		kfree_rcu(old_presp, rcu_head);



	/* it might not send the beacon for a while. send an action frame

	 * immediately to announce the channel switch.

	 */

	if (csa_settings)

		ieee80211_send_action_csa(sdata, csa_settings);



	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);

 out:

	return ret;