mac80211: support VHT association

Determine the VHT channel from the AP's VHT operation IE
(if present) and configure the hardware to that channel
if it is supported. If channel contexts cause a channel
to not be usable, try a smaller bandwidth.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 296 insertions, 72 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d2a4f78b4b0f..35d8cffc973a 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -354,6 +354,16 @@ static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
         /* determine capability flags */
         cap = vht_cap.cap;
 
+        if (sdata->u.mgd.flags & IEEE80211_STA_DISABLE_80P80MHZ) {
+                cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ;
+                cap |= IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
+        }
+
+        if (sdata->u.mgd.flags & IEEE80211_STA_DISABLE_160MHZ) {
+                cap &= ~IEEE80211_VHT_CAP_SHORT_GI_160;
+                cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
+        }
+
         /* reserve and fill IE */
         pos = skb_put(skb, sizeof(struct ieee80211_vht_cap) + 2);
         ieee80211_ie_build_vht_cap(pos, &vht_cap, cap);
@@ -543,6 +553,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
                 offset = noffset;
         }
 
+        if (WARN_ON_ONCE((ifmgd->flags & IEEE80211_STA_DISABLE_HT) &&
+                         !(ifmgd->flags & IEEE80211_STA_DISABLE_VHT)))
+                ifmgd->flags |= IEEE80211_STA_DISABLE_VHT;
+
         if (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT))
                 ieee80211_add_ht_ie(sdata, skb, assoc_data->ap_ht_param,
                                     sband, chan, sdata->smps_mode);
@@ -3183,23 +3197,270 @@ int ieee80211_max_network_latency(struct notifier_block *nb,
         return 0;
 }
 
+static u32 chandef_downgrade(struct cfg80211_chan_def *c)
+{
+        u32 ret;
+        int tmp;
+
+        switch (c->width) {
+        case NL80211_CHAN_WIDTH_20:
+                c->width = NL80211_CHAN_WIDTH_20_NOHT;
+                ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+                break;
+        case NL80211_CHAN_WIDTH_40:
+                c->width = NL80211_CHAN_WIDTH_20;
+                c->center_freq1 = c->chan->center_freq;
+                ret = IEEE80211_STA_DISABLE_40MHZ |
+                      IEEE80211_STA_DISABLE_VHT;
+                break;
+        case NL80211_CHAN_WIDTH_80:
+                tmp = (30 + c->chan->center_freq - c->center_freq1)/20;
+                /* n_P40 */
+                tmp /= 2;
+                /* freq_P40 */
+                c->center_freq1 = c->center_freq1 - 20 + 40 * tmp;
+                c->width = NL80211_CHAN_WIDTH_40;
+                ret = IEEE80211_STA_DISABLE_VHT;
+                break;
+        case NL80211_CHAN_WIDTH_80P80:
+                c->center_freq2 = 0;
+                c->width = NL80211_CHAN_WIDTH_80;
+                ret = IEEE80211_STA_DISABLE_80P80MHZ |
+                      IEEE80211_STA_DISABLE_160MHZ;
+                break;
+        case NL80211_CHAN_WIDTH_160:
+                /* n_P20 */
+                tmp = (70 + c->chan->center_freq - c->center_freq1)/20;
+                /* n_P80 */
+                tmp /= 4;
+                c->center_freq1 = c->center_freq1 - 40 + 80 * tmp;
+                c->width = NL80211_CHAN_WIDTH_80;
+                ret = IEEE80211_STA_DISABLE_80P80MHZ |
+                      IEEE80211_STA_DISABLE_160MHZ;
+                break;
+        default:
+        case NL80211_CHAN_WIDTH_20_NOHT:
+                WARN_ON_ONCE(1);
+                c->width = NL80211_CHAN_WIDTH_20_NOHT;
+                ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+                break;
+        }
+
+        WARN_ON_ONCE(!cfg80211_chandef_valid(c));
+
+        return ret;
+}
+
+static u32
+ieee80211_determine_chantype(struct ieee80211_sub_if_data *sdata,
+                             struct ieee80211_supported_band *sband,
+                             struct ieee80211_channel *channel,
+                             const struct ieee80211_ht_operation *ht_oper,
+                             const struct ieee80211_vht_operation *vht_oper,
+                             struct cfg80211_chan_def *chandef)
+{
+        struct cfg80211_chan_def vht_chandef;
+        u32 ht_cfreq, ret;
+
+        chandef->chan = channel;
+        chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
+        chandef->center_freq1 = channel->center_freq;
+        chandef->center_freq2 = 0;
+
+        if (!ht_oper || !sband->ht_cap.ht_supported) {
+                ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        chandef->width = NL80211_CHAN_WIDTH_20;
+
+        ht_cfreq = ieee80211_channel_to_frequency(ht_oper->primary_chan,
+                                                  channel->band);
+        /* check that channel matches the right operating channel */
+        if (channel->center_freq != ht_cfreq) {
+                /*
+                 * It's possible that some APs are confused here;
+                 * Netgear WNDR3700 sometimes reports 4 higher than
+                 * the actual channel in association responses, but
+                 * since we look at probe response/beacon data here
+                 * it should be OK.
+                 */
+                sdata_info(sdata,
+                           "Wrong control channel: center-freq: %d ht-cfreq: %d ht->primary_chan: %d band: %d - Disabling HT\n",
+                           channel->center_freq, ht_cfreq,
+                           ht_oper->primary_chan, channel->band);
+                ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        /* check 40 MHz support, if we have it */
+        if (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
+                switch (ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
+                case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+                        chandef->width = NL80211_CHAN_WIDTH_40;
+                        chandef->center_freq1 += 10;
+                        break;
+                case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+                        chandef->width = NL80211_CHAN_WIDTH_40;
+                        chandef->center_freq1 -= 10;
+                        break;
+                }
+        } else {
+                /* 40 MHz (and 80 MHz) must be supported for VHT */
+                ret = IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        if (!vht_oper || !sband->vht_cap.vht_supported) {
+                ret = IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        vht_chandef.chan = channel;
+        vht_chandef.center_freq1 =
+                ieee80211_channel_to_frequency(vht_oper->center_freq_seg1_idx,
+                                               channel->band);
+        vht_chandef.center_freq2 = 0;
+
+        if (vht_oper->center_freq_seg2_idx)
+                vht_chandef.center_freq2 =
+                        ieee80211_channel_to_frequency(
+                                vht_oper->center_freq_seg2_idx,
+                                channel->band);
+
+        switch (vht_oper->chan_width) {
+        case IEEE80211_VHT_CHANWIDTH_USE_HT:
+                vht_chandef.width = chandef->width;
+                break;
+        case IEEE80211_VHT_CHANWIDTH_80MHZ:
+                vht_chandef.width = NL80211_CHAN_WIDTH_80;
+                break;
+        case IEEE80211_VHT_CHANWIDTH_160MHZ:
+                vht_chandef.width = NL80211_CHAN_WIDTH_160;
+                break;
+        case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
+                vht_chandef.width = NL80211_CHAN_WIDTH_80P80;
+                break;
+        default:
+                sdata_info(sdata,
+                           "AP VHT operation IE has invalid channel width (%d), disable VHT\n",
+                           vht_oper->chan_width);
+                ret = IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        if (!cfg80211_chandef_valid(&vht_chandef)) {
+                sdata_info(sdata,
+                           "AP VHT information is invalid, disable VHT\n");
+                ret = IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        if (cfg80211_chandef_identical(chandef, &vht_chandef)) {
+                ret = 0;
+                goto out;
+        }
+
+        if (!cfg80211_chandef_compatible(chandef, &vht_chandef)) {
+                sdata_info(sdata,
+                           "AP VHT information doesn't match HT, disable VHT\n");
+                ret = IEEE80211_STA_DISABLE_VHT;
+                goto out;
+        }
+
+        *chandef = vht_chandef;
+
+        ret = 0;
+
+        while (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
+                                        IEEE80211_CHAN_DISABLED)) {
+                if (WARN_ON(chandef->width == NL80211_CHAN_WIDTH_20_NOHT)) {
+                        ret = IEEE80211_STA_DISABLE_HT |
+                              IEEE80211_STA_DISABLE_VHT;
+                        goto out;
+                }
+
+                ret = chandef_downgrade(chandef);
+        }
+
+        if (chandef->width != vht_chandef.width)
+                sdata_info(sdata,
+                           "local regulatory prevented using AP HT/VHT configuration, downgraded\n");
+
+out:
+        WARN_ON_ONCE(!cfg80211_chandef_valid(chandef));
+        return ret;
+}
+
+static u8 ieee80211_ht_vht_rx_chains(struct ieee80211_sub_if_data *sdata,
+                                     struct cfg80211_bss *cbss)
+{
+        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+        const u8 *ht_cap_ie, *vht_cap_ie;
+        const struct ieee80211_ht_cap *ht_cap;
+        const struct ieee80211_vht_cap *vht_cap;
+        u8 chains = 1;
+
+        if (ifmgd->flags & IEEE80211_STA_DISABLE_HT)
+                return chains;
+
+        ht_cap_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY,
+                                     cbss->information_elements,
+                                     cbss->len_information_elements);
+        if (ht_cap_ie && ht_cap_ie[1] >= sizeof(*ht_cap)) {
+                ht_cap = (void *)(ht_cap_ie + 2);
+                chains = ieee80211_mcs_to_chains(&ht_cap->mcs);
+                /*
+                 * TODO: use "Tx Maximum Number Spatial Streams Supported" and
+                 *       "Tx Unequal Modulation Supported" fields.
+                 */
+        }
+
+        if (ifmgd->flags & IEEE80211_STA_DISABLE_VHT)
+                return chains;
+
+        vht_cap_ie = cfg80211_find_ie(WLAN_EID_VHT_CAPABILITY,
+                                      cbss->information_elements,
+                                      cbss->len_information_elements);
+        if (vht_cap_ie && vht_cap_ie[1] >= sizeof(*vht_cap)) {
+                u8 nss;
+                u16 tx_mcs_map;
+
+                vht_cap = (void *)(vht_cap_ie + 2);
+                tx_mcs_map = le16_to_cpu(vht_cap->supp_mcs.tx_mcs_map);
+                for (nss = 8; nss > 0; nss--) {
+                        if (((tx_mcs_map >> (2 * (nss - 1))) & 3) !=
+                                        IEEE80211_VHT_MCS_NOT_SUPPORTED)
+                                break;
+                }
+                /* TODO: use "Tx Highest Supported Long GI Data Rate" field? */
+                chains = max(chains, nss);
+        }
+
+        return chains;
+}
+
 static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
                                   struct cfg80211_bss *cbss)
 {
         struct ieee80211_local *local = sdata->local;
         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
-        int ht_cfreq;
-        enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
-        const u8 *ht_oper_ie;
         const struct ieee80211_ht_operation *ht_oper = NULL;
+        const struct ieee80211_vht_operation *vht_oper = NULL;
         struct ieee80211_supported_band *sband;
         struct cfg80211_chan_def chandef;
+        int ret;
 
         sband = local->hw.wiphy->bands[cbss->channel->band];
 
-        ifmgd->flags &= ~IEEE80211_STA_DISABLE_40MHZ;
+        ifmgd->flags &= ~(IEEE80211_STA_DISABLE_40MHZ |
+                          IEEE80211_STA_DISABLE_80P80MHZ |
+                          IEEE80211_STA_DISABLE_160MHZ);
+
+        if (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT) &&
+            sband->ht_cap.ht_supported) {
+                const u8 *ht_oper_ie;
 
-        if (sband->ht_cap.ht_supported) {
                 ht_oper_ie = cfg80211_find_ie(WLAN_EID_HT_OPERATION,
                                               cbss->information_elements,
                                               cbss->len_information_elements);
@@ -3207,82 +3468,45 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
                         ht_oper = (void *)(ht_oper_ie + 2);
         }
 
-        if (ht_oper) {
-                ht_cfreq = ieee80211_channel_to_frequency(ht_oper->primary_chan,
-                                                          cbss->channel->band);
-                /* check that channel matches the right operating channel */
-                if (cbss->channel->center_freq != ht_cfreq) {
-                        /*
-                         * It's possible that some APs are confused here;
-                         * Netgear WNDR3700 sometimes reports 4 higher than
-                         * the actual channel in association responses, but
-                         * since we look at probe response/beacon data here
-                         * it should be OK.
-                         */
+        if (!(ifmgd->flags & IEEE80211_STA_DISABLE_VHT) &&
+            sband->vht_cap.vht_supported) {
+                const u8 *vht_oper_ie;
+
+                vht_oper_ie = cfg80211_find_ie(WLAN_EID_VHT_OPERATION,
+                                               cbss->information_elements,
+                                               cbss->len_information_elements);
+                if (vht_oper_ie && vht_oper_ie[1] >= sizeof(*vht_oper))
+                        vht_oper = (void *)(vht_oper_ie + 2);
+                if (vht_oper && !ht_oper) {
+                        vht_oper = NULL;
                         sdata_info(sdata,
-                                   "Wrong control channel: center-freq: %d ht-cfreq: %d ht->primary_chan: %d band: %d - Disabling HT\n",
-                                   cbss->channel->center_freq,
-                                   ht_cfreq, ht_oper->primary_chan,
-                                   cbss->channel->band);
-                        ht_oper = NULL;
+                                   "AP advertised VHT without HT, disabling both\n");
+                        sdata->flags |= IEEE80211_STA_DISABLE_HT;
+                        sdata->flags |= IEEE80211_STA_DISABLE_VHT;
                 }
         }
 
-        if (ht_oper) {
-                /*
-                 * cfg80211 already verified that the channel itself can
-                 * be used, but it didn't check that we can do the right
-                 * HT type, so do that here as well. If HT40 isn't allowed
-                 * on this channel, disable 40 MHz operation.
-                 */
-                const u8 *ht_cap_ie;
-                const struct ieee80211_ht_cap *ht_cap;
-                u8 chains = 1;
-
-                channel_type = NL80211_CHAN_HT20;
-
-                if (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
-                        switch (ht_oper->ht_param &
-                                        IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
-                        case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
-                                if (cbss->channel->flags &
-                                                IEEE80211_CHAN_NO_HT40PLUS)
-                                        ifmgd->flags |=
-                                                IEEE80211_STA_DISABLE_40MHZ;
-                                else
-                                        channel_type = NL80211_CHAN_HT40PLUS;
-                                break;
-                        case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
-                                if (cbss->channel->flags &
-                                                IEEE80211_CHAN_NO_HT40MINUS)
-                                        ifmgd->flags |=
-                                                IEEE80211_STA_DISABLE_40MHZ;
-                                else
-                                        channel_type = NL80211_CHAN_HT40MINUS;
-                                break;
-                        }
-                }
+        ifmgd->flags |= ieee80211_determine_chantype(sdata, sband,
+                                                     cbss->channel,
+                                                     ht_oper, vht_oper,
+                                                     &chandef);
 
-                ht_cap_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY,
-                                             cbss->information_elements,
-                                             cbss->len_information_elements);
-                if (ht_cap_ie && ht_cap_ie[1] >= sizeof(*ht_cap)) {
-                        ht_cap = (void *)(ht_cap_ie + 2);
-                        chains = ieee80211_mcs_to_chains(&ht_cap->mcs);
-                }
-                sdata->needed_rx_chains = min(chains, local->rx_chains);
-        } else {
-                sdata->needed_rx_chains = 1;
-                sdata->u.mgd.flags |= IEEE80211_STA_DISABLE_HT;
-        }
+        sdata->needed_rx_chains = min(ieee80211_ht_vht_rx_chains(sdata, cbss),
+                                      local->rx_chains);
 
         /* will change later if needed */
         sdata->smps_mode = IEEE80211_SMPS_OFF;
 
-        ieee80211_vif_release_channel(sdata);
-        cfg80211_chandef_create(&chandef, cbss->channel, channel_type);
-        return ieee80211_vif_use_channel(sdata, &chandef,
-                                         IEEE80211_CHANCTX_SHARED);
+        /*
+         * If this fails (possibly due to channel context sharing
+         * on incompatible channels, e.g. 80+80 and 160 sharing the
+         * same control channel) try to use a smaller bandwidth.
+         */
+        ret = ieee80211_vif_use_channel(sdata, &chandef,
+                                        IEEE80211_CHANCTX_SHARED);
+        while (ret && chandef.width != NL80211_CHAN_WIDTH_20_NOHT)
+                ifmgd->flags |= chandef_downgrade(&chandef);
+        return ret;
 }
 
 static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,