Re: [RFC] cfg80211: keep track of supported interface modes

[Dan Williams <dcbw@redhat.com>]

On Thu, 2008-08-07 at 17:21 +0200, Johannes Berg wrote:
> It is obviously good for userspace to know up front which interface modes
> a given piece of hardware might support (even if adding such an interface
> might fail later because of concurrency issues), so let's make cfg80211
> aware of that. For good measure, disallow adding interfaces in all other
> modes so drivers don't forget to announce support for one mode when they
> add it.

This makes me happy.

Thanks!
Dan

> This patch is incomplete as it doesn't modify all drivers. The driver
> modifications should be straight-forward, I'm hoping somebody else
> can pick it up and collect the necessary driver changes. Included is a
> b43 change because I tested it with that. I have also pushed an iw
> change to print out this information.
> 
> It's a bit ugly that it requires drivers to use nl80211 constants, but
> if anything mac80211 should migrate to using those completely instead
> of translating them to its own versions.
> 
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> ---
>  drivers/net/wireless/b43/main.c |   17 ++++++++++++-----
>  include/linux/nl80211.h         |    6 ++++++
>  include/net/wireless.h          |    3 +++
>  net/mac80211/main.c             |    7 +++++++
>  net/wireless/core.c             |    9 ++++++++-
>  net/wireless/nl80211.c          |   22 ++++++++++++++++++++--
>  6 files changed, 56 insertions(+), 8 deletions(-)
> 
> --- everything.orig/include/linux/nl80211.h	2008-08-07 16:26:44.000000000 +0200
> +++ everything/include/linux/nl80211.h	2008-08-07 16:39:03.000000000 +0200
> @@ -192,6 +192,10 @@ enum nl80211_commands {
>   * @NL80211_ATTR_MNTR_FLAGS: flags, nested element with NLA_FLAG attributes of
>   *      &enum nl80211_mntr_flags.
>   *
> + * @NL80211_ATTR_SUPPORTED_IFTYPES: nested attribute containing all
> + *	supported interface types, each a flag attribute with the number
> + *	of the interface mode.
> + *
>   * @NL80211_ATTR_MAX: highest attribute number currently defined
>   * @__NL80211_ATTR_AFTER_LAST: internal use
>   */
> @@ -235,6 +239,8 @@ enum nl80211_attrs {
>  	NL80211_ATTR_MPATH_NEXT_HOP,
>  	NL80211_ATTR_MPATH_INFO,
>  
> +	NL80211_ATTR_SUPPORTED_IFTYPES,
> +
>  	/* add attributes here, update the policy in nl80211.c */
>  
>  	__NL80211_ATTR_AFTER_LAST,
> --- everything.orig/include/net/wireless.h	2008-08-07 16:26:33.000000000 +0200
> +++ everything/include/net/wireless.h	2008-08-07 16:28:20.000000000 +0200
> @@ -185,6 +185,9 @@ struct wiphy {
>  	/* permanent MAC address */
>  	u8 perm_addr[ETH_ALEN];
>  
> +	/* Supported interface modes, OR together BIT(NL80211_IFTYPE_...) */
> +	u16 interface_modes;
> +
>  	/* If multiple wiphys are registered and you're handed e.g.
>  	 * a regular netdev with assigned ieee80211_ptr, you won't
>  	 * know whether it points to a wiphy your driver has registered
> --- everything.orig/net/wireless/core.c	2008-08-07 16:32:27.000000000 +0200
> +++ everything/net/wireless/core.c	2008-08-07 16:47:11.000000000 +0200
> @@ -1,7 +1,7 @@
>  /*
>   * This is the linux wireless configuration interface.
>   *
> - * Copyright 2006, 2007		Johannes Berg <johannes@sipsolutions.net>
> + * Copyright 2006-2008		Johannes Berg <johannes@sipsolutions.net>
>   */
>  
>  #include <linux/if.h>
> @@ -259,6 +259,13 @@ int wiphy_register(struct wiphy *wiphy)
>  	struct ieee80211_supported_band *sband;
>  	bool have_band = false;
>  	int i;
> +	u16 ifmodes = wiphy->interface_modes;
> +
> +	/* sanity check ifmodes */
> +	WARN_ON(!ifmodes);
> +	ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
> +	if (WARN_ON(ifmodes != wiphy->interface_modes))
> +		wiphy->interface_modes = ifmodes;
>  
>  	/* sanity check supported bands/channels */
>  	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
> --- everything.orig/net/wireless/nl80211.c	2008-08-07 16:35:22.000000000 +0200
> +++ everything/net/wireless/nl80211.c	2008-08-07 16:42:24.000000000 +0200
> @@ -106,10 +106,12 @@ static int nl80211_send_wiphy(struct sk_
>  	struct nlattr *nl_bands, *nl_band;
>  	struct nlattr *nl_freqs, *nl_freq;
>  	struct nlattr *nl_rates, *nl_rate;
> +	struct nlattr *nl_modes;
>  	enum ieee80211_band band;
>  	struct ieee80211_channel *chan;
>  	struct ieee80211_rate *rate;
>  	int i;
> +	u16 ifmodes = dev->wiphy.interface_modes;
>  
>  	hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_WIPHY);
>  	if (!hdr)
> @@ -118,6 +120,20 @@ static int nl80211_send_wiphy(struct sk_
>  	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, dev->idx);
>  	NLA_PUT_STRING(msg, NL80211_ATTR_WIPHY_NAME, wiphy_name(&dev->wiphy));
>  
> +	nl_modes = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_IFTYPES);
> +	if (!nl_modes)
> +		goto nla_put_failure;
> +
> +	i = 0;
> +	while (ifmodes) {
> +		if (ifmodes & 1)
> +			NLA_PUT_FLAG(msg, i);
> +		ifmodes >>= 1;
> +		i++;
> +	}
> +
> +	nla_nest_end(msg, nl_modes);
> +
>  	nl_bands = nla_nest_start(msg, NL80211_ATTR_WIPHY_BANDS);
>  	if (!nl_bands)
>  		goto nla_put_failure;
> @@ -408,7 +424,8 @@ static int nl80211_set_interface(struct 
>  	ifindex = dev->ifindex;
>  	dev_put(dev);
>  
> -	if (!drv->ops->change_virtual_intf) {
> +	if (!drv->ops->change_virtual_intf ||
> +	    !(drv->wiphy.interface_modes & (1 << type))) {
>  		err = -EOPNOTSUPP;
>  		goto unlock;
>  	}
> @@ -455,7 +472,8 @@ static int nl80211_new_interface(struct 
>  	if (IS_ERR(drv))
>  		return PTR_ERR(drv);
>  
> -	if (!drv->ops->add_virtual_intf) {
> +	if (!drv->ops->add_virtual_intf ||
> +	    !(drv->wiphy.interface_modes & (1 << type))) {
>  		err = -EOPNOTSUPP;
>  		goto unlock;
>  	}
> --- everything.orig/drivers/net/wireless/b43/main.c	2008-08-07 16:49:57.000000000 +0200
> +++ everything/drivers/net/wireless/b43/main.c	2008-08-07 16:57:12.000000000 +0200
> @@ -4165,11 +4165,11 @@ static int b43_op_add_interface(struct i
>  
>  	/* TODO: allow WDS/AP devices to coexist */
>  
> -	if (conf->type != IEEE80211_IF_TYPE_AP &&
> -	    conf->type != IEEE80211_IF_TYPE_MESH_POINT &&
> -	    conf->type != IEEE80211_IF_TYPE_STA &&
> -	    conf->type != IEEE80211_IF_TYPE_WDS &&
> -	    conf->type != IEEE80211_IF_TYPE_IBSS)
> +	if (WARN_ON(conf->type != IEEE80211_IF_TYPE_AP &&
> +		    conf->type != IEEE80211_IF_TYPE_MESH_POINT &&
> +		    conf->type != IEEE80211_IF_TYPE_STA &&
> +		    conf->type != IEEE80211_IF_TYPE_WDS &&
> +		    conf->type != IEEE80211_IF_TYPE_IBSS))
>  		return -EOPNOTSUPP;
>  
>  	mutex_lock(&wl->mutex);
> @@ -4649,6 +4649,13 @@ static int b43_wireless_init(struct ssb_
>  		    IEEE80211_HW_SIGNAL_DBM |
>  		    IEEE80211_HW_NOISE_DBM;
>  
> +	hw->wiphy->interface_modes =
> +		BIT(NL80211_IFTYPE_AP) |
> +		BIT(NL80211_IFTYPE_MESH_POINT) |
> +		BIT(NL80211_IFTYPE_STATION) |
> +		BIT(NL80211_IFTYPE_WDS) |
> +		BIT(NL80211_IFTYPE_ADHOC);
> +
>  	hw->queues = b43_modparam_qos ? 4 : 1;
>  	SET_IEEE80211_DEV(hw, dev->dev);
>  	if (is_valid_ether_addr(sprom->et1mac))
> --- everything.orig/net/mac80211/main.c	2008-08-07 16:42:32.000000000 +0200
> +++ everything/net/mac80211/main.c	2008-08-07 16:59:05.000000000 +0200
> @@ -1263,6 +1263,13 @@ int ieee80211_register_hw(struct ieee802
>  		}
>  	}
>  
> +	/* if low-level driver supports AP, we also support VLAN */
> +	if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_AP))
> +		local->hw.wiphy->interface_modes |= BIT(NL80211_IFTYPE_AP_VLAN);
> +
> +	/* mac80211 always supports monitor */
> +	local->hw.wiphy->interface_modes |= BIT(NL80211_IFTYPE_MONITOR);
> +
>  	result = wiphy_register(local->hw.wiphy);
>  	if (result < 0)
>  		return result;
> 
>