hostapd: Add Multi-AP protocol support

The purpose of Multi-AP specification is to enable inter-operability
across Wi-Fi access points (APs) from different vendors.

This patch introduces one new configuration parameter 'multi_ap' to
enable Multi-AP functionality and to configure the BSS as a backhaul
and/or fronthaul BSS.

Advertise vendor specific Multi-AP capabilities in (Re)Association
Response frame, if Multi-AP functionality is enabled through the
configuration parameter.

A backhaul AP must support receiving both 3addr and 4addr frames from a
backhaul STA, so create a VLAN for it just like is done for WDS, i.e.,
by calling hostapd_set_wds_sta(). Since Multi-AP requires WPA2 (never
WEP), we can safely call hostapd_set_wds_encryption() as well and we can
reuse the entire WDS condition.

To parse the Multi-AP Extension subelement, we use get_ie(): even though
that function is meant for parsing IEs, it works for subelements.

Signed-off-by: Venkateswara Naralasetty <vnaralas@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

diff --git a/hostapd/config_file.c b/hostapd/config_file.c
index 5b577fefb9304cd3a7b523222b2a7394f459a990..b76d3a3b0709ed971cd8bc1b635cee8191195c26 100644 (file)
--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -4130,6 +4130,16 @@ static int hostapd_config_fill(struct hostapd_config *conf,
        } else if (os_strcmp(buf, "coloc_intf_reporting") == 0) {
                bss->coloc_intf_reporting = atoi(pos);
 #endif /* CONFIG_OWE */
+       } else if (os_strcmp(buf, "multi_ap") == 0) {
+               int val = atoi(pos);
+
+               if (val < 0 || val > 3) {
+                       wpa_printf(MSG_ERROR, "Line %d: Invalid multi_ap '%s'",
+                                  line, buf);
+                       return -1;
+               }
+
+               bss->multi_ap = val;
        } else {
                wpa_printf(MSG_ERROR,
                           "Line %d: unknown configuration item '%s'",

diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
index 80da18cb37bdb7f3b1c8c90c9a5302bc1d8e4f8a..75f4e4ef57550ce5d6ebfe3770490b25c9e507fb 100644 (file)
--- a/hostapd/hostapd.conf
+++ b/hostapd/hostapd.conf
@@ -438,6 +438,13 @@ wmm_ac_vo_txop_limit=47
 wmm_ac_vo_acm=0
 # Note: for IEEE 802.11b mode: cWmin=3 cWmax=4 burst=102
 
+# Enable Multi-AP functionality
+# 0 = disabled (default)
+# 1 = AP support backhaul BSS
+# 2 = AP support fronthaul BSS
+# 3 = AP supports both backhaul BSS and fronthaul BSS
+#multi_ap=0
+
 # Static WEP key configuration
 #
 # The key number to use when transmitting.

diff --git a/src/ap/ap_config.h b/src/ap/ap_config.h
index 7fc984cde39d9e0e4159bbab742ceca7322a043b..902f2fc82d9e1937ea94ccb4e997bec48a6b7e11 100644 (file)
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -694,6 +694,10 @@ struct hostapd_bss_config {
        int coloc_intf_reporting;
 
        u8 send_probe_response;
+
+#define BACKHAUL_BSS 1
+#define FRONTHAUL_BSS 2
+       int multi_ap; /* bitmap of BACKHAUL_BSS, FRONTHAUL_BSS */
 };
 
 /**

diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c
index dc78210587dd1da0cca6dc956b5fb058ac862c4b..026cbf025eba3c003bd8b8bed1e3ca438c355f44 100644 (file)
--- a/src/ap/ieee802_11.c
+++ b/src/ap/ieee802_11.c
@@ -63,6 +63,22 @@ prepare_auth_resp_fils(struct hostapd_data *hapd,
                       int *is_pub);
 #endif /* CONFIG_FILS */
 
+
+u8 * hostapd_eid_multi_ap(struct hostapd_data *hapd, u8 *eid)
+{
+       u8 multi_ap_val = 0;
+
+       if (!hapd->conf->multi_ap)
+               return eid;
+       if (hapd->conf->multi_ap & BACKHAUL_BSS)
+               multi_ap_val |= MULTI_AP_BACKHAUL_BSS;
+       if (hapd->conf->multi_ap & FRONTHAUL_BSS)
+               multi_ap_val |= MULTI_AP_FRONTHAUL_BSS;
+
+       return eid + add_multi_ap_ie(eid, 9, multi_ap_val);
+}
+
+
 u8 * hostapd_eid_supp_rates(struct hostapd_data *hapd, u8 *eid)
 {
        u8 *pos = eid;
@@ -2211,6 +2227,57 @@ static u16 check_wmm(struct hostapd_data *hapd, struct sta_info *sta,
        return WLAN_STATUS_SUCCESS;
 }
 
+static u16 check_multi_ap(struct hostapd_data *hapd, struct sta_info *sta,
+                         const u8 *multi_ap_ie, size_t multi_ap_len)
+{
+       u8 multi_ap_value = 0;
+
+       sta->flags &= ~WLAN_STA_MULTI_AP;
+
+       if (!hapd->conf->multi_ap)
+               return WLAN_STATUS_SUCCESS;
+
+       if (multi_ap_ie) {
+               const u8 *multi_ap_subelem;
+
+               multi_ap_subelem = get_ie(multi_ap_ie + 4,
+                                         multi_ap_len - 4,
+                                         MULTI_AP_SUB_ELEM_TYPE);
+               if (multi_ap_subelem && multi_ap_subelem[1] == 1) {
+                       multi_ap_value = multi_ap_subelem[2];
+               } else {
+                       hostapd_logger(hapd, sta->addr,
+                                      HOSTAPD_MODULE_IEEE80211,
+                                      HOSTAPD_LEVEL_INFO,
+                                      "Multi-AP IE has missing or invalid Multi-AP subelement");
+                       return WLAN_STATUS_INVALID_IE;
+               }
+       }
+
+       if (multi_ap_value == MULTI_AP_BACKHAUL_STA)
+               sta->flags |= WLAN_STA_MULTI_AP;
+
+       if ((hapd->conf->multi_ap & BACKHAUL_BSS) &&
+           multi_ap_value == MULTI_AP_BACKHAUL_STA)
+               return WLAN_STATUS_SUCCESS;
+
+       if (hapd->conf->multi_ap & FRONTHAUL_BSS) {
+               if (multi_ap_value == MULTI_AP_BACKHAUL_STA) {
+                       hostapd_logger(hapd, sta->addr,
+                                      HOSTAPD_MODULE_IEEE80211,
+                                      HOSTAPD_LEVEL_INFO,
+                                      "Backhaul STA tries to associate with fronthaul-only BSS");
+                       return WLAN_STATUS_ASSOC_DENIED_UNSPEC;
+               }
+               return WLAN_STATUS_SUCCESS;
+       }
+
+       hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
+                      HOSTAPD_LEVEL_INFO,
+                      "Non-Multi-AP STA tries to associate with backhaul-only BSS");
+       return WLAN_STATUS_ASSOC_DENIED_UNSPEC;
+}
+
 
 static u16 copy_supp_rates(struct hostapd_data *hapd, struct sta_info *sta,
                           struct ieee802_11_elems *elems)
@@ -2467,6 +2534,11 @@ static u16 check_assoc_ies(struct hostapd_data *hapd, struct sta_info *sta,
        resp = copy_supp_rates(hapd, sta, &elems);
        if (resp != WLAN_STATUS_SUCCESS)
                return resp;
+
+       resp = check_multi_ap(hapd, sta, elems.multi_ap, elems.multi_ap_len);
+       if (resp != WLAN_STATUS_SUCCESS)
+               return resp;
+
 #ifdef CONFIG_IEEE80211N
        resp = copy_sta_ht_capab(hapd, sta, elems.ht_capabilities);
        if (resp != WLAN_STATUS_SUCCESS)
@@ -3040,6 +3112,9 @@ static u16 send_assoc_resp(struct hostapd_data *hapd, struct sta_info *sta,
        }
 #endif /* CONFIG_WPS */
 
+       if (sta && (sta->flags & WLAN_STA_MULTI_AP))
+               p = hostapd_eid_multi_ap(hapd, p);
+
 #ifdef CONFIG_P2P
        if (sta && sta->p2p_ie && hapd->p2p_group) {
                struct wpabuf *p2p_resp_ie;
@@ -4291,7 +4366,7 @@ static void handle_assoc_cb(struct hostapd_data *hapd,
                sta->flags |= WLAN_STA_WDS;
        }
 
-       if (sta->flags & WLAN_STA_WDS) {
+       if (sta->flags & (WLAN_STA_WDS | WLAN_STA_MULTI_AP)) {
                int ret;
                char ifname_wds[IFNAMSIZ + 1];
 

diff --git a/src/ap/sta_info.c b/src/ap/sta_info.c
index d0f14389020b0489831a6b8bb0d1c8481541dd18..217ca635166d9cf63c8da3a261b89a4d4d639cde 100644 (file)
--- a/src/ap/sta_info.c
+++ b/src/ap/sta_info.c
@@ -166,7 +166,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
        /* just in case */
        ap_sta_set_authorized(hapd, sta, 0);
 
-       if (sta->flags & WLAN_STA_WDS)
+       if (sta->flags & (WLAN_STA_WDS | WLAN_STA_MULTI_AP))
                hostapd_set_wds_sta(hapd, NULL, sta->addr, sta->aid, 0);
 
        if (sta->ipaddr)

diff --git a/src/ap/sta_info.h b/src/ap/sta_info.h
index 48365822e8d803ac4984a3e57a946b08d90e0164..211ef919fedd30a3d815c59a0967bef6291197bf 100644 (file)
--- a/src/ap/sta_info.h
+++ b/src/ap/sta_info.h
@@ -36,6 +36,7 @@
 #define WLAN_STA_VHT_OPMODE_ENABLED BIT(20)
 #define WLAN_STA_VENDOR_VHT BIT(21)
 #define WLAN_STA_PENDING_FILS_ERP BIT(22)
+#define WLAN_STA_MULTI_AP BIT(23)
 #define WLAN_STA_PENDING_DISASSOC_CB BIT(29)
 #define WLAN_STA_PENDING_DEAUTH_CB BIT(30)
 #define WLAN_STA_NONERP BIT(31)

diff --git a/src/common/ieee802_11_common.c b/src/common/ieee802_11_common.c
index 76f4684b9110f43d44ca5aa04f9cf662904f1f0b..733a4f39d617a0f6d87dedfbbadcc164e5dbfa57 100644 (file)
--- a/src/common/ieee802_11_common.c
+++ b/src/common/ieee802_11_common.c
@@ -126,6 +126,10 @@ static int ieee802_11_parse_vendor_specific(const u8 *pos, size_t elen,
                        elems->roaming_cons_sel = pos;
                        elems->roaming_cons_sel_len = elen;
                        break;
+               case MULTI_AP_OUI_TYPE:
+                       elems->multi_ap = pos;
+                       elems->multi_ap_len = elen;
+                       break;
                default:
                        wpa_printf(MSG_MSGDUMP, "Unknown WFA "
                                   "information element ignored "
@@ -1558,6 +1562,26 @@ size_t mbo_add_ie(u8 *buf, size_t len, const u8 *attr, size_t attr_len)
 }
 
 
+size_t add_multi_ap_ie(u8 *buf, size_t len, u8 value)
+{
+       u8 *pos = buf;
+
+       if (len < 9)
+               return 0;
+
+       *pos++ = WLAN_EID_VENDOR_SPECIFIC;
+       *pos++ = 7; /* len */
+       WPA_PUT_BE24(pos, OUI_WFA);
+       pos += 3;
+       *pos++ = MULTI_AP_OUI_TYPE;
+       *pos++ = MULTI_AP_SUB_ELEM_TYPE;
+       *pos++ = 1; /* len */
+       *pos++ = value;
+
+       return pos - buf;
+}
+
+
 static const struct country_op_class us_op_class[] = {
        { 1, 115 },
        { 2, 118 },

diff --git a/src/common/ieee802_11_common.h b/src/common/ieee802_11_common.h
index a9b248319a1527770226744fb5530766da60aaa1..99c4d023a6c6643a4d2984fa0aba2e15a2eb21cf 100644 (file)
--- a/src/common/ieee802_11_common.h
+++ b/src/common/ieee802_11_common.h
@@ -86,6 +86,7 @@ struct ieee802_11_elems {
        const u8 *roaming_cons_sel;
        const u8 *password_id;
        const u8 *oci;
+       const u8 *multi_ap;
 
        u8 ssid_len;
        u8 supp_rates_len;
@@ -133,6 +134,7 @@ struct ieee802_11_elems {
        u8 roaming_cons_sel_len;
        u8 password_id_len;
        u8 oci_len;
+       u8 multi_ap_len;
 
        struct mb_ies_info mb_ies;
 };
@@ -194,6 +196,8 @@ const u8 * get_ie_ext(const u8 *ies, size_t len, u8 ext);
 
 size_t mbo_add_ie(u8 *buf, size_t len, const u8 *attr, size_t attr_len);
 
+size_t add_multi_ap_ie(u8 *buf, size_t len, u8 value);
+
 struct country_op_class {
        u8 country_op_class;
        u8 global_op_class;

diff --git a/src/common/ieee802_11_defs.h b/src/common/ieee802_11_defs.h
index 1d2768bb8e5dcab0c5db5adbe70a09b3f8922190..ad6dbd71ab06ccd4c439cc852b3bfdb390420941 100644 (file)
--- a/src/common/ieee802_11_defs.h
+++ b/src/common/ieee802_11_defs.h
@@ -1213,6 +1213,13 @@ struct ieee80211_ampe_ie {
 #define MBO_OUI_TYPE 22
 #define OWE_IE_VENDOR_TYPE 0x506f9a1c
 #define OWE_OUI_TYPE 28
+#define MULTI_AP_OUI_TYPE 0x1B
+
+#define MULTI_AP_SUB_ELEM_TYPE 0x06
+#define MULTI_AP_TEAR_DOWN BIT(4)
+#define MULTI_AP_FRONTHAUL_BSS BIT(5)
+#define MULTI_AP_BACKHAUL_BSS BIT(6)
+#define MULTI_AP_BACKHAUL_STA BIT(7)
 
 #define WMM_OUI_TYPE 2
 #define WMM_OUI_SUBTYPE_INFORMATION_ELEMENT 0