mac80211: Support ht-cap over-rides.

This implements ht-cap over-rides for mac80211 drivers.
HT may be disabled, making an /a/b/g/n station act like an
a/b/g station.  HT40 may be disabled forcing the station to
be HT20 even if the AP and local hardware support HT40.

MAX-AMSDU may be disabled.
AMPDU-Density may be increased.
AMPDU-Factor may be decreased.

This has been successfully tested with ath9k using patched
wpa_supplicant and iw.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

9 files changed, 140 insertions, 18 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 1063a7e57d62..2577c45069e5 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -832,7 +832,7 @@ static void sta_apply_parameters(struct ieee80211_local *local,
         }
 
         if (params->ht_capa)
-                ieee80211_ht_cap_ie_to_sta_ht_cap(sband,
+                ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
                                                   params->ht_capa,
                                                   &sta->sta.ht_cap);
 
diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index 988c7ec0898c..7e0ac9791fd6 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -18,7 +18,82 @@
 #include "ieee80211_i.h"
 #include "rate.h"
 
-void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_supported_band *sband,
+bool ieee80111_cfg_override_disables_ht40(struct ieee80211_sub_if_data *sdata)
+{
+        const __le16 flg = cpu_to_le16(IEEE80211_HT_CAP_SUP_WIDTH_20_40);
+        if ((sdata->u.mgd.ht_capa_mask.cap_info & flg) &&
+            !(sdata->u.mgd.ht_capa.cap_info & flg))
+                return true;
+        return false;
+}
+
+void __check_htcap_disable(struct ieee80211_sub_if_data *sdata,
+                           struct ieee80211_sta_ht_cap *ht_cap,
+                           u16 flag)
+{
+        __le16 le_flag = cpu_to_le16(flag);
+        if (sdata->u.mgd.ht_capa_mask.cap_info & le_flag) {
+                if (!(sdata->u.mgd.ht_capa.cap_info & le_flag))
+                        ht_cap->cap &= ~flag;
+        }
+}
+
+void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
+                                     struct ieee80211_sta_ht_cap *ht_cap)
+{
+        u8 *scaps = (u8 *)(&sdata->u.mgd.ht_capa.mcs.rx_mask);
+        u8 *smask = (u8 *)(&sdata->u.mgd.ht_capa_mask.mcs.rx_mask);
+        int i;
+
+        if (sdata->vif.type != NL80211_IFTYPE_STATION) {
+                WARN_ON_ONCE(sdata->vif.type != NL80211_IFTYPE_STATION);
+                return;
+        }
+
+        /* NOTE:  If you add more over-rides here, update register_hw
+         * ht_capa_mod_msk logic in main.c as well.
+         * And, if this method can ever change ht_cap.ht_supported, fix
+         * the check in ieee80211_add_ht_ie.
+         */
+
+        /* check for HT over-rides, MCS rates first. */
+        for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
+                u8 m = smask[i];
+                ht_cap->mcs.rx_mask[i] &= ~m; /* turn off all masked bits */
+                /* Add back rates that are supported */
+                ht_cap->mcs.rx_mask[i] |= (m & scaps[i]);
+        }
+
+        /* Force removal of HT-40 capabilities? */
+        __check_htcap_disable(sdata, ht_cap, IEEE80211_HT_CAP_SUP_WIDTH_20_40);
+        __check_htcap_disable(sdata, ht_cap, IEEE80211_HT_CAP_SGI_40);
+
+        /* Allow user to disable the max-AMSDU bit. */
+        __check_htcap_disable(sdata, ht_cap, IEEE80211_HT_CAP_MAX_AMSDU);
+
+        /* Allow user to decrease AMPDU factor */
+        if (sdata->u.mgd.ht_capa_mask.ampdu_params_info &
+            IEEE80211_HT_AMPDU_PARM_FACTOR) {
+                u8 n = sdata->u.mgd.ht_capa.ampdu_params_info
+                        & IEEE80211_HT_AMPDU_PARM_FACTOR;
+                if (n < ht_cap->ampdu_factor)
+                        ht_cap->ampdu_factor = n;
+        }
+
+        /* Allow the user to increase AMPDU density. */
+        if (sdata->u.mgd.ht_capa_mask.ampdu_params_info &
+            IEEE80211_HT_AMPDU_PARM_DENSITY) {
+                u8 n = (sdata->u.mgd.ht_capa.ampdu_params_info &
+                        IEEE80211_HT_AMPDU_PARM_DENSITY)
+                        >> IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT;
+                if (n > ht_cap->ampdu_density)
+                        ht_cap->ampdu_density = n;
+        }
+}
+
+
+void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_sub_if_data *sdata,
+                                       struct ieee80211_supported_band *sband,
                                        struct ieee80211_ht_cap *ht_cap_ie,
                                        struct ieee80211_sta_ht_cap *ht_cap)
 {
@@ -102,6 +177,12 @@ void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_supported_band *sband,
         /* handle MCS rate 32 too */
         if (sband->ht_cap.mcs.rx_mask[32/8] & ht_cap_ie->mcs.rx_mask[32/8] & 1)
                 ht_cap->mcs.rx_mask[32/8] |= 1;
+
+        /*
+         * If user has specified capability over-rides, take care
+         * of that here.
+         */
+        ieee80211_apply_htcap_overrides(sdata, ht_cap);
 }
 
 void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta, bool tx)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 17661df1515f..762243e469df 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -449,6 +449,9 @@ struct ieee80211_if_managed {
          */
         int rssi_min_thold, rssi_max_thold;
         int last_ave_beacon_signal;
+
+        struct ieee80211_ht_cap ht_capa; /* configured ht-cap over-rides */
+        struct ieee80211_ht_cap ht_capa_mask; /* Valid parts of ht_capa */
 };
 
 struct ieee80211_if_ibss {
@@ -1252,7 +1255,11 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
                                        struct net_device *dev);
 
 /* HT */
-void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_supported_band *sband,
+bool ieee80111_cfg_override_disables_ht40(struct ieee80211_sub_if_data *sdata);
+void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
+                                     struct ieee80211_sta_ht_cap *ht_cap);
+void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_sub_if_data *sdata,
+                                       struct ieee80211_supported_band *sband,
                                        struct ieee80211_ht_cap *ht_cap_ie,
                                        struct ieee80211_sta_ht_cap *ht_cap);
 void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata,
@@ -1407,7 +1414,7 @@ void ieee80211_recalc_smps(struct ieee80211_local *local);
 size_t ieee80211_ie_split(const u8 *ies, size_t ielen,
                           const u8 *ids, int n_ids, size_t offset);
 size_t ieee80211_ie_split_vendor(const u8 *ies, size_t ielen, size_t offset);
-u8 *ieee80211_ie_build_ht_cap(u8 *pos, struct ieee80211_supported_band *sband,
+u8 *ieee80211_ie_build_ht_cap(u8 *pos, struct ieee80211_sta_ht_cap *ht_cap,
                               u16 cap);
 u8 *ieee80211_ie_build_ht_info(u8 *pos,
                                 struct ieee80211_sta_ht_cap *ht_cap,
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index f0106d331938..dddedfad5404 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -558,6 +558,19 @@ ieee80211_default_mgmt_stypes[NUM_NL80211_IFTYPES] = {
         },
 };
 
+static const struct ieee80211_ht_cap mac80211_ht_capa_mod_mask = {
+        .ampdu_params_info = IEEE80211_HT_AMPDU_PARM_FACTOR |
+                             IEEE80211_HT_AMPDU_PARM_DENSITY,
+
+        .cap_info = cpu_to_le16(IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
+                                IEEE80211_HT_CAP_MAX_AMSDU |
+                                IEEE80211_HT_CAP_SGI_40),
+        .mcs = {
+                .rx_mask = { 0xff, 0xff, 0xff, 0xff, 0xff,
+                             0xff, 0xff, 0xff, 0xff, 0xff, },
+        },
+};
+
 struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
                                         const struct ieee80211_ops *ops)
 {
@@ -631,6 +644,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
         local->user_power_level = -1;
         local->uapsd_queues = IEEE80211_DEFAULT_UAPSD_QUEUES;
         local->uapsd_max_sp_len = IEEE80211_DEFAULT_MAX_SP_LEN;
+        wiphy->ht_capa_mod_mask = &mac80211_ht_capa_mod_mask;
 
         INIT_LIST_HEAD(&local->interfaces);
 
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index b3a125f60347..ee82d2f7f114 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -366,7 +366,7 @@ int mesh_add_ht_cap_ie(struct sk_buff *skb,
                 return -ENOMEM;
 
         pos = skb_put(skb, 2 + sizeof(struct ieee80211_ht_cap));
-        ieee80211_ie_build_ht_cap(pos, sband, sband->ht_cap.cap);
+        ieee80211_ie_build_ht_cap(pos, &sband->ht_cap, sband->ht_cap.cap);
 
         return 0;
 }
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 0140e88a8220..7314372b12ba 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -101,7 +101,8 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
         set_sta_flag(sta, WLAN_STA_WME);
         sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
         if (elems->ht_cap_elem)
-                ieee80211_ht_cap_ie_to_sta_ht_cap(sband, elems->ht_cap_elem,
+                ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
+                                                  elems->ht_cap_elem,
                                                   &sta->sta.ht_cap);
         rate_control_rate_init(sta);
 
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 0f58122edffa..8925138736ef 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -207,6 +207,7 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
                 channel_type = NL80211_CHAN_HT20;
 
                 if (!(ap_ht_cap_flags & IEEE80211_HT_CAP_40MHZ_INTOLERANT) &&
+                    !ieee80111_cfg_override_disables_ht40(sdata) &&
                     (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) &&
                     (hti->ht_param & IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
                         switch(hti->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
@@ -1118,6 +1119,8 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 
         /* on the next assoc, re-program HT parameters */
         sdata->ht_opmode_valid = false;
+        memset(&ifmgd->ht_capa, 0, sizeof(ifmgd->ht_capa));
+        memset(&ifmgd->ht_capa_mask, 0, sizeof(ifmgd->ht_capa_mask));
 
         local->power_constr_level = 0;
 
@@ -1611,7 +1614,7 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
                 sdata->flags &= ~IEEE80211_SDATA_OPERATING_GMODE;
 
         if (elems.ht_cap_elem && !(ifmgd->flags & IEEE80211_STA_DISABLE_11N))
-                ieee80211_ht_cap_ie_to_sta_ht_cap(sband,
+                ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
                                 elems.ht_cap_elem, &sta->sta.ht_cap);
 
         ap_ht_cap_flags = sta->sta.ht_cap.cap;
@@ -1980,7 +1983,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 
                 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 
-                ieee80211_ht_cap_ie_to_sta_ht_cap(sband,
+                ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
                                 elems.ht_cap_elem, &sta->sta.ht_cap);
 
                 ap_ht_cap_flags = sta->sta.ht_cap.cap;
@@ -2640,6 +2643,13 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
                         ifmgd->flags |= IEEE80211_STA_DISABLE_11N;
 
 
+        if (req->flags & ASSOC_REQ_DISABLE_HT)
+                ifmgd->flags |= IEEE80211_STA_DISABLE_11N;
+
+        memcpy(&ifmgd->ht_capa, &req->ht_capa, sizeof(ifmgd->ht_capa));
+        memcpy(&ifmgd->ht_capa_mask, &req->ht_capa_mask,
+               sizeof(ifmgd->ht_capa_mask));
+
         if (req->ie && req->ie_len) {
                 memcpy(wk->ie, req->ie, req->ie_len);
                 wk->ie_len = req->ie_len;
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index e2cb00df8c36..1118393d79de 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -979,7 +979,8 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
         }
 
         if (sband->ht_cap.ht_supported)
-                pos = ieee80211_ie_build_ht_cap(pos, sband, sband->ht_cap.cap);
+                pos = ieee80211_ie_build_ht_cap(pos, &sband->ht_cap,
+                                                sband->ht_cap.cap);
 
         /*
          * If adding more here, adjust code in main.c
@@ -1518,7 +1519,7 @@ void ieee80211_disable_rssi_reports(struct ieee80211_vif *vif)
 }
 EXPORT_SYMBOL(ieee80211_disable_rssi_reports);
 
-u8 *ieee80211_ie_build_ht_cap(u8 *pos, struct ieee80211_supported_band *sband,
+u8 *ieee80211_ie_build_ht_cap(u8 *pos, struct ieee80211_sta_ht_cap *ht_cap,
                               u16 cap)
 {
         __le16 tmp;
@@ -1533,13 +1534,13 @@ u8 *ieee80211_ie_build_ht_cap(u8 *pos, struct ieee80211_supported_band *sband,
         pos += sizeof(u16);
 
         /* AMPDU parameters */
-        *pos++ = sband->ht_cap.ampdu_factor |
-                 (sband->ht_cap.ampdu_density <<
+        *pos++ = ht_cap->ampdu_factor |
+                 (ht_cap->ampdu_density <<
                         IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT);
 
         /* MCS set */
-        memcpy(pos, &sband->ht_cap.mcs, sizeof(sband->ht_cap.mcs));
-        pos += sizeof(sband->ht_cap.mcs);
+        memcpy(pos, &ht_cap->mcs, sizeof(ht_cap->mcs));
+        pos += sizeof(ht_cap->mcs);
 
         /* extended capabilities */
         pos += sizeof(__le16);
diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index 3dd5a89e99a7..6884a2d986dc 100644
--- a/net/mac80211/work.c
+++ b/net/mac80211/work.c
@@ -94,7 +94,8 @@ static int ieee80211_compatible_rates(const u8 *supp_rates, int supp_rates_len,
 
 /* frame sending functions */
 
-static void ieee80211_add_ht_ie(struct sk_buff *skb, const u8 *ht_info_ie,
+static void ieee80211_add_ht_ie(struct ieee80211_sub_if_data *sdata,
+                                struct sk_buff *skb, const u8 *ht_info_ie,
                                 struct ieee80211_supported_band *sband,
                                 struct ieee80211_channel *channel,
                                 enum ieee80211_smps_mode smps)
@@ -102,7 +103,10 @@ static void ieee80211_add_ht_ie(struct sk_buff *skb, const u8 *ht_info_ie,
         struct ieee80211_ht_info *ht_info;
         u8 *pos;
         u32 flags = channel->flags;
-        u16 cap = sband->ht_cap.cap;
+        u16 cap;
+        struct ieee80211_sta_ht_cap ht_cap;
+
+        BUILD_BUG_ON(sizeof(ht_cap) != sizeof(sband->ht_cap));
 
         if (!sband->ht_cap.ht_supported)
                 return;
@@ -113,9 +117,13 @@ static void ieee80211_add_ht_ie(struct sk_buff *skb, const u8 *ht_info_ie,
         if (ht_info_ie[1] < sizeof(struct ieee80211_ht_info))
                 return;
 
+        memcpy(&ht_cap, &sband->ht_cap, sizeof(ht_cap));
+        ieee80211_apply_htcap_overrides(sdata, &ht_cap);
+
         ht_info = (struct ieee80211_ht_info *)(ht_info_ie + 2);
 
         /* determine capability flags */
+        cap = ht_cap.cap;
 
         switch (ht_info->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
         case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
@@ -154,7 +162,7 @@ static void ieee80211_add_ht_ie(struct sk_buff *skb, const u8 *ht_info_ie,
 
         /* reserve and fill IE */
         pos = skb_put(skb, sizeof(struct ieee80211_ht_cap) + 2);
-        ieee80211_ie_build_ht_cap(pos, sband, cap);
+        ieee80211_ie_build_ht_cap(pos, &ht_cap, cap);
 }
 
 static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
@@ -329,7 +337,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
 
         if (wk->assoc.use_11n && wk->assoc.wmm_used &&
             local->hw.queues >= 4)
-                ieee80211_add_ht_ie(skb, wk->assoc.ht_information_ie,
+                ieee80211_add_ht_ie(sdata, skb, wk->assoc.ht_information_ie,
                                     sband, wk->chan, wk->assoc.smps);
 
         /* if present, add any custom non-vendor IEs that go after HT */