Implement dynamic MCS selection based on signal strength in vWIFI driver

scripts/hostapd.conf

@@ -2,7 +2,7 @@ interface=vw0
 driver=nl80211
 debug=1
 ctrl_interface=/var/run/hostapd
-ctrl_interface_group=0
+ctrl_interface_group=root
 channel=6
 ssid=test
 wpa=2
@@ -12,4 +12,4 @@ wpa_pairwise=CCMP
 
 # Beacon interval (kibi-us : 1.024 ms)
 beacon_int=100
-dtim_period=1
+dtim_period=1

vwifi.c

@@ -88,7 +88,8 @@ struct vwifi_vif {
     struct wireless_dev wdev;
     struct net_device *ndev;
     struct net_device_stats stats;
-
+    int manual_mcs;
+    bool manual_mcs_set;
     size_t ssid_len;
     /* Currently connected BSS id */
     u8 bssid[ETH_ALEN];
@@ -1345,7 +1346,6 @@ static int vwifi_get_station(struct wiphy *wiphy,
                              struct station_info *sinfo)
 {
     struct vwifi_vif *vif = ndev_get_vwifi_vif(dev);
-
     bool found_sta = false;
     switch (dev->ieee80211_ptr->iftype) {
     case NL80211_IFTYPE_AP:;
@@ -1403,8 +1403,18 @@ static int vwifi_get_station(struct wiphy *wiphy,
     sinfo->tx_failed = vif->stats.tx_dropped;
     sinfo->tx_bytes = vif->stats.tx_bytes;
     sinfo->rx_bytes = vif->stats.rx_bytes;
+
+
+    /* Log byte counters for debugging */
+    pr_info(
+        "vwifi: Station %pM tx_bytes %llu, rx_bytes %llu, tx_packets %u, "
+        "rx_packets %u, tx_failed %u\n",
+        mac, sinfo->tx_bytes, sinfo->rx_bytes, sinfo->tx_packets,
+        sinfo->rx_packets, sinfo->tx_failed);
+
     /* For CFG80211_SIGNAL_TYPE_MBM, value is expressed in dBm */
     sinfo->signal = rand_int_smooth(-100, -30, jiffies);
+    pr_info("vwifi: Station %pM signal %d dBm (raw)\n", mac, sinfo->signal);
     sinfo->inactive_time = jiffies_to_msecs(jiffies - vif->active_time);
     /*
      * Using 802.11n (HT) as the PHY, configure as follows:
@@ -1425,18 +1435,72 @@ static int vwifi_get_station(struct wiphy *wiphy,
      * https://semfionetworks.com/blog/mcs-table-updated-with-80211ax-data-rates/
      * IEEE 802.11n : https://zh.wikipedia.org/zh-tw/IEEE_802.11n
      */
-    sinfo->rxrate.flags |= RATE_INFO_FLAGS_MCS;
-    sinfo->rxrate.mcs = 31;
+
+
+
+    /* Checks vif->manual_mcs_set to use vif->manual_mcs if set;
+     * Assigns modulation string for manual MCS ; else auto change based
+     * on signal strength
+     */
+    int mcs_index;
+    const char *modulation;
+    if (vif->manual_mcs_set) {
+        mcs_index = vif->manual_mcs;
+        switch (mcs_index) {
+        case 7:
+            modulation = "BPSK";
+            break;
+        case 15:
+            modulation = "QPSK";
+            break;
+        case 23:
+            modulation = "16-QAM";
+            break;
+        case 31:
+            modulation = "64-QAM";
+            break;
+        default:
+            modulation = "Unknown";
+            break;
+        }
+        pr_info("vwifi: Station %pM using manual MCS %d (%s)\n", mac, mcs_index,
+                modulation);
+    } else {
+        if (sinfo->signal > -50) {
+            mcs_index = 31;
+            modulation = "64-QAM";
+        } else if (sinfo->signal > -70 && sinfo->signal <= -50) {
+            mcs_index = 23;
+            modulation = "16-QAM";
+        } else if (sinfo->signal > -90 && sinfo->signal <= -70) {
+            mcs_index = 15;
+            modulation = "QPSK";
+        } else {
+            mcs_index = 7;
+            modulation = "BPSK";
+        }
+        pr_info(
+            "vwifi: Station %pM signal %d dBm, using modulation %s (MCS %d)\n",
+            mac, sinfo->signal, modulation, mcs_index);
+    }
+
+    /* Configure RX and TX rates */
+    sinfo->rxrate.flags = RATE_INFO_FLAGS_MCS;
+    sinfo->rxrate.mcs = mcs_index;
     sinfo->rxrate.bw = RATE_INFO_BW_20;
     sinfo->rxrate.n_bonded_ch = 1;
 
-    sinfo->txrate.flags |= RATE_INFO_FLAGS_MCS;
-    sinfo->txrate.mcs = 31;
+    sinfo->txrate.flags = RATE_INFO_FLAGS_MCS;
+    sinfo->txrate.mcs = mcs_index;
     sinfo->txrate.bw = RATE_INFO_BW_20;
     sinfo->txrate.n_bonded_ch = 1;
+
+    /* Log rate configuration for verification */
+    pr_info("vwifi: Station %pM txrate MCS %d, rxrate MCS %d\n", mac,
+            sinfo->txrate.mcs, sinfo->rxrate.mcs);
+
     return 0;
 }
-
 /* dump station callback -- resume dump at index @idx */
 static int vwifi_dump_station(struct wiphy *wiphy,
                               struct net_device *dev,
@@ -2150,6 +2214,66 @@ static int vwifi_leave_ibss(struct wiphy *wiphy, struct net_device *ndev)
 
     return 0;
 }
+/* Callback to handle manual bitrate configuration via iw */
+static int vwifi_set_bitrate_mask(struct wiphy *wiphy,
+                                  struct net_device *dev,
+                                  unsigned int link_id,
+                                  const u8 *peer,
+                                  const struct cfg80211_bitrate_mask *mask)
+{
+    struct vwifi_vif *vif = netdev_priv(dev);
+    int mcs_index = -1;
+
+    if (!vif) {
+        pr_err("vwifi: Failed to get vwifi_vif for dev %s\n", dev->name);
+        return -EINVAL;
+    }
+
+    if (vif->sme_state != SME_CONNECTED) {
+        pr_err("vwifi: Dev %s not connected, cannot set bitrate\n", dev->name);
+        return -EINVAL;
+    }
+
+    pr_info("vwifi: set_bitrate_mask called for dev %s, link_id %u, peer %pM\n",
+            dev->name, link_id, peer ? peer : vif->bssid);
+    pr_info("vwifi: 2.4GHz MCS mask: %02x %02x %02x %02x\n",
+            mask->control[NL80211_BAND_2GHZ].ht_mcs[0],
+            mask->control[NL80211_BAND_2GHZ].ht_mcs[1],
+            mask->control[NL80211_BAND_2GHZ].ht_mcs[2],
+            mask->control[NL80211_BAND_2GHZ].ht_mcs[3]);
+
+    /* Find the requested MCS index */
+    for (int i = 0; i < 4; i++) {
+        if (mask->control[NL80211_BAND_2GHZ].ht_mcs[i]) {
+            for (int j = 0; j < 8; j++) {
+                if (mask->control[NL80211_BAND_2GHZ].ht_mcs[i] & (1 << j)) {
+                    mcs_index = i * 8 + j;
+                    pr_info("vwifi: Requested MCS index %d\n", mcs_index);
+                    break;
+                }
+            }
+            if (mcs_index != -1)
+                break;
+        }
+    }
+
+    if (mcs_index == -1) {
+        pr_err("vwifi: No valid MCS index found\n");
+        return -EINVAL;
+    }
+
+    if (mcs_index != 7 && mcs_index != 15 && mcs_index != 23 &&
+        mcs_index != 31) {
+        pr_err("vwifi: Unsupported MCS index %d\n", mcs_index);
+        return -EINVAL;
+    }
+
+    vif->manual_mcs = mcs_index;
+    vif->manual_mcs_set = true;
+    pr_info("vwifi: Set manual MCS %d for dev %s\n", mcs_index, dev->name);
+
+    return 0;
+}
 
 /* Structure of functions for FullMAC 80211 drivers. Functions implemented
  * along with fields/flags in the wiphy structure represent driver features.
@@ -2175,6 +2299,7 @@ static struct cfg80211_ops vwifi_cfg_ops = {
     .get_tx_power = vwifi_get_tx_power,
     .join_ibss = vwifi_join_ibss,
     .leave_ibss = vwifi_leave_ibss,
+    .set_bitrate_mask = vwifi_set_bitrate_mask,
 };
 
 /* Macro for defining 2GHZ channel array */
@@ -2191,14 +2316,15 @@ static struct cfg80211_ops vwifi_cfg_ops = {
         .center_freq = 5000 + (5 * (channel)),            \
     }
 
+
 /* Macro for defining rate table */
 #define RATE_ENT(_rate, _hw_value)                   \
     {                                                \
         .bitrate = (_rate), .hw_value = (_hw_value), \
     }
 
 /* Array of "supported" channels in 2GHz band. It is required for wiphy. */
-static const struct ieee80211_channel vwifi_supported_channels_2ghz[] = {
+static struct ieee80211_channel vwifi_supported_channels_2ghz[] = {
     CHAN_2GHZ(1, 2412),  CHAN_2GHZ(2, 2417),  CHAN_2GHZ(3, 2422),
     CHAN_2GHZ(4, 2427),  CHAN_2GHZ(5, 2432),  CHAN_2GHZ(6, 2437),
     CHAN_2GHZ(7, 2442),  CHAN_2GHZ(8, 2447),  CHAN_2GHZ(9, 2452),
@@ -2221,16 +2347,35 @@ static const struct ieee80211_channel vwifi_supported_channels_5ghz[] = {
 /* Array of supported rates, required to support those next rates
  * for 2GHz and 5GHz band.
  */
-static const struct ieee80211_rate vwifi_supported_rates[] = {
+static struct ieee80211_rate vwifi_supported_rates[] = {
     RATE_ENT(10, 0x1),    RATE_ENT(20, 0x2),    RATE_ENT(55, 0x4),
     RATE_ENT(110, 0x8),   RATE_ENT(60, 0x10),   RATE_ENT(90, 0x20),
     RATE_ENT(120, 0x40),  RATE_ENT(180, 0x80),  RATE_ENT(240, 0x100),
     RATE_ENT(360, 0x200), RATE_ENT(480, 0x400), RATE_ENT(540, 0x800),
 };
 
-/* Describes supported band of 2GHz. */
-static struct ieee80211_supported_band nf_band_2ghz;
-
+static struct ieee80211_supported_band nf_band_2ghz = {
+    .band = NL80211_BAND_2GHZ,
+    .channels = vwifi_supported_channels_2ghz,
+    .n_channels = ARRAY_SIZE(vwifi_supported_channels_2ghz),
+    .bitrates = vwifi_supported_rates,
+    .n_bitrates = ARRAY_SIZE(vwifi_supported_rates),
+    .ht_cap =
+        {
+            .ht_supported = true,
+            .cap = IEEE80211_HT_CAP_SGI_20 | IEEE80211_HT_CAP_GRN_FLD |
+                   IEEE80211_HT_CAP_MAX_AMSDU |
+                   IEEE80211_HT_CAP_SUP_WIDTH_20_40,
+            .mcs =
+                {
+                    .rx_mask = {0xff, 0xff, 0xff, 0xff}, /* MCS 0-31 */
+                    .rx_highest = cpu_to_le16(300),
+                    .tx_params = IEEE80211_HT_MCS_TX_DEFINED,
+                },
+            .ampdu_factor = IEEE80211_HT_MAX_AMPDU_64K,
+            .ampdu_density = IEEE80211_HT_MPDU_DENSITY_16,
+        },
+};
 /* Describes supported band of 5GHz. */
 static struct ieee80211_supported_band nf_band_5ghz;