AP MLD: Fix advertisement of MLD capabilities

Previously, hostapd directly advertised the MLD capabilities received
from the driver. Since this information is exchanged during
initialization time only, the driver will advertise the maximum
supported values. hostapd should parse it and then based on the current
situation fill the values accordingly.

For example, the maximum number of simultaneous links is supposed to be
a value between 0 and 14, which is the number of affiliated APs minus 1.
The driver advertises this value as 5 and hostapd, irrespective of the
current active links, puts 5 in the frames.

Fix this by parsing the value from the driver capabilities and then
using the values as per the current situation of the links. The
advertised values will be used as the upper limit.

Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>

diff --git a/src/ap/ieee802_11_eht.c b/src/ap/ieee802_11_eht.c
index fde8d8c08a10a010ce90db0669f2eb17dba8484f..7365057adb00fbf718f876b56b778d83f6f18a66 100644 (file)
--- a/src/ap/ieee802_11_eht.c
+++ b/src/ap/ieee802_11_eht.c
@@ -450,6 +450,8 @@ static u8 * hostapd_eid_eht_basic_ml_common(struct hostapd_data *hapd,
        size_t len, slice_len;
        u8 link_id;
        u8 common_info_len;
+       u16 mld_cap;
+       u8 max_simul_links, active_links;
 
        /*
         * As the Multi-Link element can exceed the size of 255 bytes need to
@@ -499,9 +501,26 @@ static u8 * hostapd_eid_eht_basic_ml_common(struct hostapd_data *hapd,
                   hapd->iface->mld_eml_capa);
        wpabuf_put_le16(buf, hapd->iface->mld_eml_capa);
 
+       mld_cap = hapd->iface->mld_mld_capa;
+       max_simul_links = mld_cap & EHT_ML_MLD_CAPA_MAX_NUM_SIM_LINKS_MASK;
+       active_links = hapd->mld->num_links - 1;
+
+       if (active_links > max_simul_links) {
+               wpa_printf(MSG_ERROR,
+                          "MLD: Error in max simultaneous links, advertised: 0x%x current: 0x%x",
+                          max_simul_links, active_links);
+               active_links = max_simul_links;
+       }
+
+       mld_cap &= ~EHT_ML_MLD_CAPA_MAX_NUM_SIM_LINKS_MASK;
+       mld_cap |= active_links & EHT_ML_MLD_CAPA_MAX_NUM_SIM_LINKS_MASK;
+
+       /* TODO: Advertise T2LM based on driver support as well */
+       mld_cap &= ~EHT_ML_MLD_CAPA_TID_TO_LINK_MAP_NEG_SUPP_MSK;
+
        wpa_printf(MSG_DEBUG, "MLD: MLD Capabilities and Operations=0x%x",
-                  hapd->iface->mld_mld_capa);
-       wpabuf_put_le16(buf, hapd->iface->mld_mld_capa);
+                  mld_cap);
+       wpabuf_put_le16(buf, mld_cap);
 
        if (include_mld_id) {
                wpa_printf(MSG_DEBUG, "MLD: AP MLD ID=0x%x",