Re: [PATCH] ath10k: add dynamic vlan support

[Manikanta Pubbisetty <mpubbise@codeaurora.org>]

Johannes,

It seems like commit db3bdcb9c3ff ("mac80211: allow AP_VLAN operation on 
crypto controlled devices") has broken 4-addr operation on crypto 
controlled devices as reported by sebastian.
The commit was mainly focused in addressing the problem in supporting 
VLANs on crypto controlled devices but since 4-addr mode is also 
dependent on AP_VLAN interface, this commit breaks the 4-addr AP mode.

I have couple of ideas on how to address the problem,

1) Add a new hw_flag and based on the hardware flag, allow/disallow the 
creation of AP_VLAN interface.

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d2279b2..301d9c38 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2084,6 +2084,11 @@ struct ieee80211_txq {
   * @IEEE80211_HW_DOESNT_SUPPORT_QOS_NDP: The driver (or firmware) 
doesn't
   *     support QoS NDP for AP probing - that's most likely a driver 
bug.
   *
+ * @IEEE80211_HW_SUPPORTS_SW_ENCRYPT: Device is capable of transmitting
+ *     frames encrypted in software, only valid when SW_CRYPTO_CONTROL
+ *     is enabled. Based on this flag, mac80211 can allow/disallow VLAN
+ *     operations in the BSS.
+ *
   * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing 
arrays
   */
  enum ieee80211_hw_flags {
@@ -2129,6 +2134,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA,
         IEEE80211_HW_DEAUTH_NEED_MGD_TX_PREP,
         IEEE80211_HW_DOESNT_SUPPORT_QOS_NDP,
+       IEEE80211_HW_SUPPORTS_SW_ENCRYPT,

         /* keep last, obviously */
         NUM_IEEE80211_HW_FLAGS
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 555e389..c825d27 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1736,6 +1736,11 @@ int ieee80211_if_add(struct ieee80211_local 
*local, const char *name,

         ASSERT_RTNL();

+       if ((type == NL80211_IFTYPE_AP_VLAN) && !params->use_4addr &&
+           ieee80211_hw_check(local->hw, SW_CRYPTO_CONTROL) &&
+           !ieee80211_hw_check(local->hw, SUPPORTS_SW_ENCRYPT))
+              return -EOPNOTSUPP;
+
         if (type == NL80211_IFTYPE_P2P_DEVICE || type == 
NL80211_IFTYPE_NAN) {
                 struct wireless_dev *wdev;

2) Allow mac80211 to call set_key for GTKs on AP_VLAN interfaces for 
crypto controlled devices, let the driver decide whether to return '1' 
or some error code based on their support for transmitting sw encrypted 
frames. I am little skeptical with this approach as drivers are totally 
unaware of AP_VLAN interfaces.

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index ee0d0cc..0ff5597 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -167,7 +167,8 @@ static int ieee80211_key_enable_hw_accel(struct 
ieee80211_key *key)
                  * The driver doesn't know anything about VLAN 
interfaces.
                  * Hence, don't send GTKs for VLAN interfaces to the 
driver.
                  */
-               if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
+               if ((!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
+                   !ieee80211_hw_check(&key->local->hw, 
SW_CRYPTO_CONTROL)))
                         goto out_unsupported;
         }

Please let me know which is the better way to deal the problem.

Thanks,
Manikanta


On 2018-04-24 14:39, Sebastian Gottschall wrote:
> consider my comment regarding vlan_ap.
> this patch will break wds ap / wds sta support with latest mac80211
> (see also my post on the wireless mailing list about the breaking
> patch in mac80211)
> so AP_VLAN must be masked always for all chipsets. otherwise wds
> breaks and this is not just a guess. i tested it yesterday using this
> patch and found
> the cause of the issue
> 
> the following lines
> 
>   +    if (test_bit(WMI_SERVICE_PER_PACKET_SW_ENCRYPT, 
> ar->wmi.svc_map)) {
> +        ar->hw->wiphy->interface_modes |= BIT(NL80211_IFTYPE_AP_VLAN);
> +        ar->hw->wiphy->software_iftypes |= 
> BIT(NL80211_IFTYPE_AP_VLAN);
> +    }
> 
> 
> must be just
> 
> +        ar->hw->wiphy->interface_modes |= BIT(NL80211_IFTYPE_AP_VLAN);
> +        ar->hw->wiphy->software_iftypes |= 
> BIT(NL80211_IFTYPE_AP_VLAN);
> 
> everthing else will cause a regression
> 
> Am 24.04.2018 um 10:09 schrieb Kalle Valo:
>> Manikanta Pubbisetty <mpubbise@codeaurora.org> writes:
>> 
>>> Mutlicast/broadcast traffic destined for a particular vlan group will
>>> always be encrypted in software. To enable dynamic VLANs, it requires
>>> driver support for sending software encrypted packets.
>>> 
>>> In ath10k, sending sw encrypted frames is allowed only when we insmod
>>> the driver with cryptmode param set to 1, this configuration disables
>>> hardware crypto and enables RAW mode implicitly. Since, enabling raw
>>> mode has performance impact, this cannot be considered as an ideal
>>> solution for supporting VLANs in the driver.
>>> 
>>> As an alternative take, in this approach, cryptographic keys for
>>> unicast traffic(per peer PTKs) and keys for non-vlan group traffic
>>> will be configured in hardware, allowing hardware encryption for 
>>> unicast
>>> and non-vlan group traffic. Only vlan group traffic will be encrypted 
>>> in
>>> software and pushed to the target with encap mode set to RAW in the 
>>> TX
>>> descriptors.
>>> 
>>> Not all firmwares can support this type of key configuration(having 
>>> few
>>> keys installed in hardware and few only in software); for this 
>>> purpose a
>>> new WMI service flag "WMI_SERVICE_PER_PACKET_SW_ENCRYPT" is 
>>> introduced to
>>> advertise this support.
>>> 
>>> Also, adding the logic required to send sw encrypted frames in raw 
>>> mode.
>>> 
>>> Tested this change on QCA9984(firmware version 10.4-3.5.3-00057).
>>> 
>>> Signed-off-by: Manikanta Pubbisetty <mpubbise@codeaurora.org>
>> Your name in patchwork is wrong and hence my script uses the wrong
>> name. Please fix it by registering to patchwork[1] where it's possible
>> to change your name during registration, but only one time. If that
>> doesn't work then send a request to helpdesk@kernel.org and the admins
>> can fix it.
>> 
>> [1] https://patchwork.kernel.org/register/
>> 

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