Re: [PATCH] wireless: support configuring vdev mac addr on create.

[Arend van Spriel <arend@broadcom.com>]

On 09/30/14 20:43, greearb@candelatech.com wrote:
> From: Ben Greear<greearb@candelatech.com>
>
> This is useful when creating virtual-stations, and probably
> APs and other devices as well.  Keeps udev from mucking with
> things it shouldn't, since the default MAC is never seen
> by udev when specified on the cmd-line during creation.
>
> Signed-off-by: Ben Greear<greearb@candelatech.com>
> ---
>   include/net/cfg80211.h       | 6 +++---
>   include/uapi/linux/nl80211.h | 3 +++
>   net/mac80211/iface.c         | 5 ++++-
>   net/mac80211/main.c          | 1 +
>   net/wireless/nl80211.c       | 2 +-
>   5 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index e1641e6..de9a67f 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -319,9 +319,9 @@ struct ieee80211_supported_band {
>   /**
>    * struct vif_params - describes virtual interface parameters
>    * @use_4addr: use 4-address frames
> - * @macaddr: address to use for this virtual interface. This will only
> - * 	be used for non-netdevice interfaces. If this parameter is set
> - * 	to zero address the driver may determine the address as needed.
> + * @macaddr: address to use for this virtual interface.
> + * 	If this parameter is set to zero address the driver may
> + *	determine the address as needed.
>    */
>   struct vif_params {
>          int use_4addr;
> diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> index 4b28dc0..fd14703 100644
> --- a/include/uapi/linux/nl80211.h
> +++ b/include/uapi/linux/nl80211.h
> @@ -4042,6 +4042,8 @@ enum nl80211_ap_sme_features {
>    *	multiplexing powersave, ie. can turn off all but one chain
>    *	and then wake the rest up as required after, for example,
>    *	rts/cts handshake.
> + * @NL80211_FEATURE_MAC_ON_CREATE: Device supports configuring
> + *	the vdev's MAC address upon creation.
>    */
>   enum nl80211_feature_flags {
>   	NL80211_FEATURE_SK_TX_STATUS			= 1<<  0,
> @@ -4070,6 +4072,7 @@ enum nl80211_feature_flags {
>   	NL80211_FEATURE_ACKTO_ESTIMATION		= 1<<  23,
>   	NL80211_FEATURE_STATIC_SMPS			= 1<<  24,
>   	NL80211_FEATURE_DYNAMIC_SMPS			= 1<<  25,
> +	NL80211_FEATURE_MAC_ON_CREATE			= 1<<  26,

Hi Ben,

It is unclear to me why this should be ap_sme feature flag. As your 
description indicates this is a device feature/capability so it seems 
more appropriate that this would be a wiphy flag.

Regards,
Arend

>   };
>
>   /**
> diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
> index 878bfca..ba5d0d5 100644
> --- a/net/mac80211/iface.c
> +++ b/net/mac80211/iface.c
> @@ -1715,7 +1715,10 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
>   		}
>
>   		ieee80211_assign_perm_addr(local, ndev->perm_addr, type);
> -		memcpy(ndev->dev_addr, ndev->perm_addr, ETH_ALEN);
> +		if (params&&  !is_zero_ether_addr(params->macaddr))

I would expect checkpatch will complain on these whitespace errors. Also 
would be better to use is_valid_ether_addr() to assure it is not a 
multicast/broadcast address.

Regards,
Arend

> +			memcpy(ndev->dev_addr, params->macaddr, ETH_ALEN);
> +		else
> +			memcpy(ndev->dev_addr, ndev->perm_addr, ETH_ALEN);
>   		SET_NETDEV_DEV(ndev, wiphy_dev(local->hw.wiphy));
>
>   		/* don't use IEEE80211_DEV_TO_SUB_IF -- it checks too much */
> diff --git a/net/mac80211/main.c b/net/mac80211/main.c
> index 8106770..eb7bdd1 100644
> --- a/net/mac80211/main.c
> +++ b/net/mac80211/main.c
> @@ -550,6 +550,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
>   			   NL80211_FEATURE_SAE |
>   			   NL80211_FEATURE_HT_IBSS |
>   			   NL80211_FEATURE_VIF_TXPOWER |
> +			   NL80211_FEATURE_MAC_ON_CREATE |
>   			   NL80211_FEATURE_USERSPACE_MPM;
>
>   	if (!ops->hw_scan)
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 8a010bd..cf79707 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -2605,7 +2605,7 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
>   	    !(rdev->wiphy.interface_modes&  (1<<  type)))
>   		return -EOPNOTSUPP;
>
> -	if (type == NL80211_IFTYPE_P2P_DEVICE&&  info->attrs[NL80211_ATTR_MAC]) {
> +	if (info->attrs[NL80211_ATTR_MAC]) {
>   		nla_memcpy(params.macaddr, info->attrs[NL80211_ATTR_MAC],
>   			   ETH_ALEN);
>   		if (!is_valid_ether_addr(params.macaddr))