Commit 63fc33ce authored by Daniel Drake's avatar Daniel Drake Committed by John W. Linville
Browse files

[PATCH] mac80211: improved 802.11g CTS protection 



Currently, CTS protection is partially implemented twice:
 1. via prism2 ioctls, only used by hostapd
 2. via STA beacon parsing, recorded in sta.use_protection but never used
    (other than printed in debugfs)

Protection control should be implemented on a per-subif basis. For example,
a single physical device may be running a soft AP on one channel, and a STA
on another. The AP interface should use protection based on what hostapd told
it, and the STA interface should use protection based on beacon parsing.
These should operate independantly: one subif using protection should not
influence the other.

To implement this, I moved the use_protection flag into ieee80211_sub_if_data
and removed the device-global cts_protect_erp_frames flag.

I also made the PRISM2_PARAM_CTS_PROTECT_ERP_FRAMES write operation only
available for AP interfaces, to avoid any possibility of the user messing with
the behaviour of a STA.

Signed-off-by: default avatarDaniel Drake <dsd@gentoo.org>
Signed-off-by: default avatarJiri Benc <jbenc@suse.cz>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 5628221c

net/mac80211/debugfs_netdev.c

+1 −1
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ static ssize_t ieee80211_if_fmt_flags( 
			 sdata->u.sta.authenticated ? "AUTH\n" : "",

			 sdata->u.sta.associated ? "ASSOC\n" : "",

			 sdata->u.sta.probereq_poll ? "PROBEREQ POLL\n" : "",

			 sdata->u.sta.use_protection ? "CTS prot\n" : "");

			 sdata->use_protection ? "CTS prot\n" : "");

}

__IEEE80211_IF_FILE(flags);

net/mac80211/ieee80211.c

+2 −3
Original line number Diff line number Diff line
@@ -442,7 +442,7 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx) 
	if (!tx->u.tx.rate)

		return TXRX_DROP;

	if (tx->u.tx.mode->mode == MODE_IEEE80211G &&

	    tx->local->cts_protect_erp_frames && tx->fragmented &&

	    tx->sdata->use_protection && tx->fragmented &&

	    extra.nonerp) {

		tx->u.tx.last_frag_rate = tx->u.tx.rate;

		tx->u.tx.probe_last_frag = extra.probe ? 1 : 0;
@@ -868,8 +868,7 @@ ieee80211_tx_h_misc(struct ieee80211_txrx_data *tx) 
	 * for the frame. */

	if (mode->mode == MODE_IEEE80211G &&

	    (tx->u.tx.rate->flags & IEEE80211_RATE_ERP) &&

	    tx->u.tx.unicast &&

	    tx->local->cts_protect_erp_frames &&

	    tx->u.tx.unicast && tx->sdata->use_protection &&

	    !(control->flags & IEEE80211_TXCTL_USE_RTS_CTS))

		control->flags |= IEEE80211_TXCTL_USE_CTS_PROTECT;

net/mac80211/ieee80211_i.h

+1 −2
Original line number Diff line number Diff line
@@ -241,7 +241,6 @@ struct ieee80211_if_sta { 
	unsigned int authenticated:1;

	unsigned int associated:1;

	unsigned int probereq_poll:1;

	unsigned int use_protection:1;

	unsigned int create_ibss:1;

	unsigned int mixed_cell:1;

	unsigned int wmm_enabled:1;
@@ -284,6 +283,7 @@ struct ieee80211_sub_if_data { 
	int mc_count;

	unsigned int allmulti:1;

	unsigned int promisc:1;

	unsigned int use_protection:1; /* CTS protect ERP frames */



	struct net_device_stats stats;

	int drop_unencrypted;
@@ -444,7 +444,6 @@ struct ieee80211_local { 
	int *basic_rates[NUM_IEEE80211_MODES];



	int rts_threshold;

	int cts_protect_erp_frames;

	int fragmentation_threshold;

	int short_retry_limit; /* dot11ShortRetryLimit */

	int long_retry_limit; /* dot11LongRetryLimit */

net/mac80211/ieee80211_ioctl.c

+5 −2
Original line number Diff line number Diff line
@@ -1180,7 +1180,10 @@ static int ieee80211_ioctl_prism2_param(struct net_device *dev, 
		break;



	case PRISM2_PARAM_CTS_PROTECT_ERP_FRAMES:

		local->cts_protect_erp_frames = value;

		if (sdata->type != IEEE80211_IF_TYPE_AP)

			ret = -ENOENT;

		else

			sdata->use_protection = value;

		break;



	case PRISM2_PARAM_PREAMBLE:
@@ -1303,7 +1306,7 @@ static int ieee80211_ioctl_get_prism2_param(struct net_device *dev, 
		break;



	case PRISM2_PARAM_CTS_PROTECT_ERP_FRAMES:

		*param = local->cts_protect_erp_frames;

		*param = sdata->use_protection;

		break;



	case PRISM2_PARAM_PREAMBLE:

net/mac80211/ieee80211_sta.c

+4 −4
Original line number Diff line number Diff line
@@ -316,12 +316,11 @@ static void ieee80211_sta_wmm_params(struct net_device *dev, 


static void ieee80211_handle_erp_ie(struct net_device *dev, u8 erp_value)

{

	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);

	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;



	if (use_protection != !!ifsta->use_protection) {

	if (use_protection != sdata->use_protection) {

		if (net_ratelimit()) {

			printk(KERN_DEBUG "%s: CTS protection %s (BSSID="

			       MAC_FMT ")\n",
@@ -329,8 +328,7 @@ static void ieee80211_handle_erp_ie(struct net_device *dev, u8 erp_value) 
			       use_protection ? "enabled" : "disabled",

			       MAC_ARG(ifsta->bssid));

		}

		ifsta->use_protection = use_protection ? 1 : 0;

		local->cts_protect_erp_frames = use_protection;

		sdata->use_protection = use_protection;

	}

}
@@ -390,6 +388,7 @@ static void ieee80211_set_associated(struct net_device *dev, 
				     struct ieee80211_if_sta *ifsta, int assoc)

{

	union iwreq_data wrqu;

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);



	if (ifsta->associated == assoc)

		return;
@@ -417,6 +416,7 @@ static void ieee80211_set_associated(struct net_device *dev, 
		ieee80211_sta_send_associnfo(dev, ifsta);

	} else {

		netif_carrier_off(dev);

		sdata->use_protection = 0;

		memset(wrqu.ap_addr.sa_data, 0, ETH_ALEN);

	}

	wrqu.ap_addr.sa_family = ARPHRD_ETHER;

CRA Git | Maintained and supported by SUSTech CRA and CCSE