cfg80211/mac80211: better channel handling
Currently (all tested with hwsim) you can do stupid
things like setting up an AP on a certain channel,
then adding another virtual interface and making
that associate on another channel -- this will make
the beaconing to move channel but obviously without
the necessary IEs data update.
In order to improve this situation, first make the
configuration APIs (cfg80211 and nl80211) aware of
multi-channel operation -- we'll eventually need
that in the future anyway. There's one userland API
change and one API addition. The API change is that
now SET_WIPHY must be called with virtual interface
index rather than only wiphy index in order to take
effect for that interface -- luckily all current
users (hostapd) do that. For monitor interfaces, the
old setting is preserved, but monitors are always
slaved to other devices anyway so no guarantees.
The second userland API change is the introduction
of a per virtual interface SET_CHANNEL command, that
hostapd should use going forward to make it easier
to understand what's going on (it can automatically
detect a kernel with this command).
Other than mac80211, no existing cfg80211 drivers
are affected by this change because they only allow
a single virtual interface.
mac80211, however, now needs to be aware that the
channel settings are per interface now, and needs
to disallow (for now) real multi-channel operation,
which is another important part of this patch.
One of the immediate benefits is that you can now
start hostapd to operate on a hardware that already
has a connection on another virtual interface, as
long as you specify the same channel.
Note that two things are left unhandled (this is an
improvement -- not a complete fix):
* different HT/no-HT modes
currently you could start an HT AP and then
connect to a non-HT network on the same channel
which would configure the hardware for no HT;
that can be fixed fairly easily
* CSA
An AP we're connected to on a virtual interface
might indicate switching channels, and in that
case we would follow it, regardless of how many
other interfaces are operating; this requires
more effort to fix but is pretty rare after all
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-05-05 07:25:02 -06:00
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/*
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* mac80211 - channel management
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*/
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2010-05-05 07:28:27 -06:00
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#include <linux/nl80211.h>
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cfg80211/mac80211: better channel handling
Currently (all tested with hwsim) you can do stupid
things like setting up an AP on a certain channel,
then adding another virtual interface and making
that associate on another channel -- this will make
the beaconing to move channel but obviously without
the necessary IEs data update.
In order to improve this situation, first make the
configuration APIs (cfg80211 and nl80211) aware of
multi-channel operation -- we'll eventually need
that in the future anyway. There's one userland API
change and one API addition. The API change is that
now SET_WIPHY must be called with virtual interface
index rather than only wiphy index in order to take
effect for that interface -- luckily all current
users (hostapd) do that. For monitor interfaces, the
old setting is preserved, but monitors are always
slaved to other devices anyway so no guarantees.
The second userland API change is the introduction
of a per virtual interface SET_CHANNEL command, that
hostapd should use going forward to make it easier
to understand what's going on (it can automatically
detect a kernel with this command).
Other than mac80211, no existing cfg80211 drivers
are affected by this change because they only allow
a single virtual interface.
mac80211, however, now needs to be aware that the
channel settings are per interface now, and needs
to disallow (for now) real multi-channel operation,
which is another important part of this patch.
One of the immediate benefits is that you can now
start hostapd to operate on a hardware that already
has a connection on another virtual interface, as
long as you specify the same channel.
Note that two things are left unhandled (this is an
improvement -- not a complete fix):
* different HT/no-HT modes
currently you could start an HT AP and then
connect to a non-HT network on the same channel
which would configure the hardware for no HT;
that can be fixed fairly easily
* CSA
An AP we're connected to on a virtual interface
might indicate switching channels, and in that
case we would follow it, regardless of how many
other interfaces are operating; this requires
more effort to fix but is pretty rare after all
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-05-05 07:25:02 -06:00
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#include "ieee80211_i.h"
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2010-05-28 06:26:23 -06:00
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static enum ieee80211_chan_mode
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cfg80211/mac80211: better channel handling
Currently (all tested with hwsim) you can do stupid
things like setting up an AP on a certain channel,
then adding another virtual interface and making
that associate on another channel -- this will make
the beaconing to move channel but obviously without
the necessary IEs data update.
In order to improve this situation, first make the
configuration APIs (cfg80211 and nl80211) aware of
multi-channel operation -- we'll eventually need
that in the future anyway. There's one userland API
change and one API addition. The API change is that
now SET_WIPHY must be called with virtual interface
index rather than only wiphy index in order to take
effect for that interface -- luckily all current
users (hostapd) do that. For monitor interfaces, the
old setting is preserved, but monitors are always
slaved to other devices anyway so no guarantees.
The second userland API change is the introduction
of a per virtual interface SET_CHANNEL command, that
hostapd should use going forward to make it easier
to understand what's going on (it can automatically
detect a kernel with this command).
Other than mac80211, no existing cfg80211 drivers
are affected by this change because they only allow
a single virtual interface.
mac80211, however, now needs to be aware that the
channel settings are per interface now, and needs
to disallow (for now) real multi-channel operation,
which is another important part of this patch.
One of the immediate benefits is that you can now
start hostapd to operate on a hardware that already
has a connection on another virtual interface, as
long as you specify the same channel.
Note that two things are left unhandled (this is an
improvement -- not a complete fix):
* different HT/no-HT modes
currently you could start an HT AP and then
connect to a non-HT network on the same channel
which would configure the hardware for no HT;
that can be fixed fairly easily
* CSA
An AP we're connected to on a virtual interface
might indicate switching channels, and in that
case we would follow it, regardless of how many
other interfaces are operating; this requires
more effort to fix but is pretty rare after all
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-05-05 07:25:02 -06:00
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__ieee80211_get_channel_mode(struct ieee80211_local *local,
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struct ieee80211_sub_if_data *ignore)
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{
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struct ieee80211_sub_if_data *sdata;
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WARN_ON(!mutex_is_locked(&local->iflist_mtx));
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list_for_each_entry(sdata, &local->interfaces, list) {
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if (sdata == ignore)
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continue;
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if (!ieee80211_sdata_running(sdata))
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continue;
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if (sdata->vif.type == NL80211_IFTYPE_MONITOR)
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continue;
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if (sdata->vif.type == NL80211_IFTYPE_STATION &&
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!sdata->u.mgd.associated)
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continue;
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if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
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if (!sdata->u.ibss.ssid_len)
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continue;
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if (!sdata->u.ibss.fixed_channel)
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return CHAN_MODE_HOPPING;
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}
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if (sdata->vif.type == NL80211_IFTYPE_AP &&
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!sdata->u.ap.beacon)
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continue;
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return CHAN_MODE_FIXED;
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}
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return CHAN_MODE_UNDEFINED;
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}
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enum ieee80211_chan_mode
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ieee80211_get_channel_mode(struct ieee80211_local *local,
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struct ieee80211_sub_if_data *ignore)
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{
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enum ieee80211_chan_mode mode;
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mutex_lock(&local->iflist_mtx);
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mode = __ieee80211_get_channel_mode(local, ignore);
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mutex_unlock(&local->iflist_mtx);
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return mode;
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}
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2010-05-05 07:28:27 -06:00
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bool ieee80211_set_channel_type(struct ieee80211_local *local,
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struct ieee80211_sub_if_data *sdata,
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enum nl80211_channel_type chantype)
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{
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struct ieee80211_sub_if_data *tmp;
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enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
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bool result;
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mutex_lock(&local->iflist_mtx);
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list_for_each_entry(tmp, &local->interfaces, list) {
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if (tmp == sdata)
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continue;
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if (!ieee80211_sdata_running(tmp))
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continue;
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switch (tmp->vif.bss_conf.channel_type) {
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case NL80211_CHAN_NO_HT:
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case NL80211_CHAN_HT20:
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superchan = tmp->vif.bss_conf.channel_type;
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break;
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case NL80211_CHAN_HT40PLUS:
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WARN_ON(superchan == NL80211_CHAN_HT40MINUS);
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superchan = NL80211_CHAN_HT40PLUS;
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break;
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case NL80211_CHAN_HT40MINUS:
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WARN_ON(superchan == NL80211_CHAN_HT40PLUS);
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superchan = NL80211_CHAN_HT40MINUS;
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break;
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}
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}
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switch (superchan) {
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case NL80211_CHAN_NO_HT:
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case NL80211_CHAN_HT20:
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/*
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* allow any change that doesn't go to no-HT
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* (if it already is no-HT no change is needed)
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*/
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if (chantype == NL80211_CHAN_NO_HT)
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break;
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superchan = chantype;
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break;
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case NL80211_CHAN_HT40PLUS:
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case NL80211_CHAN_HT40MINUS:
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/* allow smaller bandwidth and same */
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if (chantype == NL80211_CHAN_NO_HT)
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break;
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if (chantype == NL80211_CHAN_HT20)
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break;
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if (superchan == chantype)
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break;
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result = false;
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goto out;
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}
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local->_oper_channel_type = superchan;
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if (sdata)
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sdata->vif.bss_conf.channel_type = chantype;
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result = true;
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out:
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mutex_unlock(&local->iflist_mtx);
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return result;
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}
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