On Mon, 2009-01-26 at 16:22 -0800, Luis R. Rodriguez wrote:
> Monitor mode is able to TX by using injected frames. We should
> not allow injected frames to be sent unless allowed by regulatory
> rules. Since AP mode uses a monitor interfaces to transmit
> management frames we have to take care to not break AP mode as
> well while resolving this. We deal with this by allowing compliant
> APs solutions to inform mac80211 if their monitor interface is
> intended to be used for an AP by setting a cfg80211 flag for the
> monitor interface. hostapd, for example, currently does its own
> checks to ensure AP mode is not used on channels which require radar
> detection. Once such solutions are available it can can enable this
> flag.
>
> Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>
> ---
>
> This now works, I moved the check as recommended by Johannes to
> ieee80211_monitor_start_xmit(), the issues I ran into earlier seem
> to be due to a work around set in place for 11w.
>
> include/linux/nl80211.h | 3 +++
> include/net/cfg80211.h | 4 ++++
> net/mac80211/tx.c | 14 ++++++++++++++
> net/wireless/nl80211.c | 1 +
> 4 files changed, 22 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
> index 76aae3d..3357907 100644
> --- a/include/linux/nl80211.h
> +++ b/include/linux/nl80211.h
> @@ -705,6 +705,8 @@ enum nl80211_reg_rule_flags {
> * @NL80211_MNTR_FLAG_OTHER_BSS: disable BSSID filtering
> * @NL80211_MNTR_FLAG_COOK_FRAMES: report frames after processing.
> * overrides all other flags.
> + * @NL80211_MNTR_FLAG_AP_MGT: this monitor interface is used for AP mode
> + * to be able to inject management frames.
> *
> * @__NL80211_MNTR_FLAG_AFTER_LAST: internal use
> * @NL80211_MNTR_FLAG_MAX: highest possible monitor flag
> @@ -716,6 +718,7 @@ enum nl80211_mntr_flags {
> NL80211_MNTR_FLAG_CONTROL,
> NL80211_MNTR_FLAG_OTHER_BSS,
> NL80211_MNTR_FLAG_COOK_FRAMES,
> + NL80211_MNTR_FLAG_AP_MGT,
>
> /* keep last */
> __NL80211_MNTR_FLAG_AFTER_LAST,
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index dd1fd51..fe65c64 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -255,6 +255,9 @@ struct station_info {
> * @MONITOR_FLAG_CONTROL: pass control frames
> * @MONITOR_FLAG_OTHER_BSS: disable BSSID filtering
> * @MONITOR_FLAG_COOK_FRAMES: report frames after processing
> + * @MONITOR_FLAG_AP_MGT: informs us this monitor interface is
> + * used by a driver for AP mode to be able to inject management
> + * frames.
> */
> enum monitor_flags {
> MONITOR_FLAG_FCSFAIL = 1<<NL80211_MNTR_FLAG_FCSFAIL,
> @@ -262,6 +265,7 @@ enum monitor_flags {
> MONITOR_FLAG_CONTROL = 1<<NL80211_MNTR_FLAG_CONTROL,
> MONITOR_FLAG_OTHER_BSS = 1<<NL80211_MNTR_FLAG_OTHER_BSS,
> MONITOR_FLAG_COOK_FRAMES = 1<<NL80211_MNTR_FLAG_COOK_FRAMES,
> + MONITOR_FLAG_AP_MGT = 1<<NL80211_MNTR_FLAG_AP_MGT,
> };
>
> /**
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index 7b013fb..e752f6d 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -1432,11 +1432,25 @@ int ieee80211_master_start_xmit(struct sk_buff *skb, struct net_device *dev)
> int ieee80211_monitor_start_xmit(struct sk_buff *skb,
> struct net_device *dev)
> {
> + struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
> struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
> + struct ieee80211_channel *chan = local->hw.conf.channel;
> struct ieee80211_radiotap_header *prthdr =
> (struct ieee80211_radiotap_header *)skb->data;
> u16 len_rthdr;
>
> + /* Frame injection is not allowed if beaconing is not allowed
Comment style, /* on a single line please :)
> + * or if we need radar detection. Beaconing is usually not allowed when
> + * the mode or operation (Adhoc, AP, Mesh) does not support DFS.
> + * Since AP mode uses monitor interfaces to inject/TX management
> + * frames we make AP mode the exception to this rule as its
> + * implementation can deal with radar detection by itself. */
and end with */ on its own line.
> + if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_MONITOR))
> + return TX_DROP;
Huh? You're in monitor_start_xmit. If that goes wrong, something is
horribly broken and beyond WARN_ON. Please just remove this.
Other than that, looks good.
johannes
Attachment:
signature.asc
Description: This is a digitally signed message part
