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				https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
				synced 2025-11-04 16:52:06 +10:00 
			
		
		
		
	This follows wireless-testing 9236d838c9
("cfg80211: fix extension channel checks to initiate communication") and
fixes accidental case fall-through. Without this fix, HT40 is entirely
blocked.
Signed-off-by: Mark Mentovai <mark@moxienet.com>
Cc: stable@kernel.org
Acked-by: Luis R. Rodriguez <lrodriguez@atheros.com
Signed-off-by: John W. Linville <linville@tuxdriver.com>
		
	
			
		
			
				
	
	
		
			136 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			136 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * This file contains helper code to handle channel
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 * settings and keeping track of what is possible at
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 * any point in time.
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 *
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 * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
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 */
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#include <net/cfg80211.h>
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#include "core.h"
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struct ieee80211_channel *
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rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
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		  int freq, enum nl80211_channel_type channel_type)
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{
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	struct ieee80211_channel *chan;
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	struct ieee80211_sta_ht_cap *ht_cap;
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	chan = ieee80211_get_channel(&rdev->wiphy, freq);
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	/* Primary channel not allowed */
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	if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
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		return NULL;
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	if (channel_type == NL80211_CHAN_HT40MINUS &&
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	    chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
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		return NULL;
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	else if (channel_type == NL80211_CHAN_HT40PLUS &&
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		 chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
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		return NULL;
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	ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
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	if (channel_type != NL80211_CHAN_NO_HT) {
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		if (!ht_cap->ht_supported)
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			return NULL;
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		if (channel_type != NL80211_CHAN_HT20 &&
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		    (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
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		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
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			return NULL;
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	}
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	return chan;
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}
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static bool can_beacon_sec_chan(struct wiphy *wiphy,
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				struct ieee80211_channel *chan,
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				enum nl80211_channel_type channel_type)
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{
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	struct ieee80211_channel *sec_chan;
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	int diff;
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	switch (channel_type) {
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	case NL80211_CHAN_HT40PLUS:
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		diff = 20;
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		break;
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	case NL80211_CHAN_HT40MINUS:
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		diff = -20;
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		break;
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	default:
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		return false;
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	}
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	sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
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	if (!sec_chan)
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		return false;
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	/* we'll need a DFS capability later */
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	if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
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			       IEEE80211_CHAN_PASSIVE_SCAN |
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			       IEEE80211_CHAN_NO_IBSS |
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			       IEEE80211_CHAN_RADAR))
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		return false;
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	return true;
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}
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int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
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		      struct wireless_dev *wdev, int freq,
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		      enum nl80211_channel_type channel_type)
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{
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	struct ieee80211_channel *chan;
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	int result;
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	if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
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		wdev = NULL;
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	if (wdev) {
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		ASSERT_WDEV_LOCK(wdev);
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		if (!netif_running(wdev->netdev))
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			return -ENETDOWN;
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	}
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	if (!rdev->ops->set_channel)
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		return -EOPNOTSUPP;
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	chan = rdev_freq_to_chan(rdev, freq, channel_type);
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	if (!chan)
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		return -EINVAL;
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	/* Both channels should be able to initiate communication */
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	if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC ||
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		     wdev->iftype == NL80211_IFTYPE_AP ||
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		     wdev->iftype == NL80211_IFTYPE_AP_VLAN ||
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		     wdev->iftype == NL80211_IFTYPE_MESH_POINT ||
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		     wdev->iftype == NL80211_IFTYPE_P2P_GO)) {
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		switch (channel_type) {
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		case NL80211_CHAN_HT40PLUS:
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		case NL80211_CHAN_HT40MINUS:
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			if (!can_beacon_sec_chan(&rdev->wiphy, chan,
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						 channel_type)) {
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				printk(KERN_DEBUG
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				       "cfg80211: Secondary channel not "
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				       "allowed to initiate communication\n");
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				return -EINVAL;
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			}
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			break;
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		default:
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			break;
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		}
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	}
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	result = rdev->ops->set_channel(&rdev->wiphy,
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					wdev ? wdev->netdev : NULL,
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					chan, channel_type);
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	if (result)
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		return result;
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	if (wdev)
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		wdev->channel = chan;
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	return 0;
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}
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