taxonomy: Store Probe Request frames in hostapd_sta_info

A weakness in the initial client taxonomy mechanism is from storing both
the Probe and Associate in struct sta_info. struct sta_info is created
after a client associates (or starts authentication frame exchange),
which means that any Probe Request frames sent prior to association are
not retained. The Associate Request frame has to be seen, and then
another Probe Request frame after association, before we have a
signature for the client.

Most clients send lots of Probe Request frames (lots and lots and lots
of Probes, actually), but a few do not. ChromeOS is notably sparing in
sending Probe Request frames, it can take a long time before a signature
for a ChromeOS device is available.

Store the most recent Probe Request frame in struct hostapd_sta_info
tracking list. When a struct sta_info is created, move the Probe Request
frame information from struct hostapd_sta_info to struct sta_info.

Signed-off-by: dgentry@google.com (Denton Gentry)
Signed-off-by: denny@geekhold.com (Denton Gentry)
Signed-off-by: rofrankel@google.com (Richard Frankel)
Signed-off-by: richard@frankel.tv (Richard Frankel)

src/ap/beacon.c

@@ -600,7 +600,7 @@ void sta_track_expire(struct hostapd_iface *iface, int force)
 			   MAC2STR(info->addr));
 		dl_list_del(&info->list);
 		iface->num_sta_seen--;
-		os_free(info);
+		sta_track_del(info);
 	}
 }
 
@@ -676,6 +676,23 @@ sta_track_seen_on(struct hostapd_iface *iface, const u8 *addr,
 }
 
 
+#ifdef CONFIG_TAXONOMY
+void sta_track_claim_taxonomy_info(struct hostapd_iface *iface, const u8 *addr,
+				   struct wpabuf **probe_ie_taxonomy)
+{
+	struct hostapd_sta_info *info;
+
+	info = sta_track_get(iface, addr);
+	if (!info)
+		return;
+
+	wpabuf_free(*probe_ie_taxonomy);
+	*probe_ie_taxonomy = info->probe_ie_taxonomy;
+	info->probe_ie_taxonomy = NULL;
+}
+#endif /* CONFIG_TAXONOMY */
+
+
 void handle_probe_req(struct hostapd_data *hapd,
 		      const struct ieee80211_mgmt *mgmt, size_t len,
 		      int ssi_signal)
@@ -787,9 +804,16 @@ void handle_probe_req(struct hostapd_data *hapd,
 
 #ifdef CONFIG_TAXONOMY
 	{
-		struct sta_info *sta = ap_get_sta(hapd, mgmt->sa);
-		if (sta)
+		struct sta_info *sta;
+		struct hostapd_sta_info *info;
+
+		if ((sta = ap_get_sta(hapd, mgmt->sa)) != NULL) {
 			taxonomy_sta_info_probe_req(hapd, sta, ie, ie_len);
+		} else if ((info = sta_track_get(hapd->iface,
+						 mgmt->sa)) != NULL) {
+			taxonomy_hostapd_sta_info_probe_req(hapd, info,
+							    ie, ie_len);
+		}
 	}
 #endif /* CONFIG_TAXONOMY */
 
@@ -961,6 +985,16 @@ static u8 * hostapd_probe_resp_offloads(struct hostapd_data *hapd,
 #endif /* NEED_AP_MLME */
 
 
+void sta_track_del(struct hostapd_sta_info *info)
+{
+#ifdef CONFIG_TAXONOMY
+	wpabuf_free(info->probe_ie_taxonomy);
+	info->probe_ie_taxonomy = NULL;
+#endif /* CONFIG_TAXONOMY */
+	os_free(info);
+}
+
+
 int ieee802_11_build_ap_params(struct hostapd_data *hapd,
 			       struct wpa_driver_ap_params *params)
 {

src/ap/beacon.h

@@ -22,9 +22,12 @@ int ieee802_11_build_ap_params(struct hostapd_data *hapd,
 			       struct wpa_driver_ap_params *params);
 void ieee802_11_free_ap_params(struct wpa_driver_ap_params *params);
 void sta_track_add(struct hostapd_iface *iface, const u8 *addr);
+void sta_track_del(struct hostapd_sta_info *info);
 void sta_track_expire(struct hostapd_iface *iface, int force);
 struct hostapd_data *
 sta_track_seen_on(struct hostapd_iface *iface, const u8 *addr,
 		  const char *ifname);
+void sta_track_claim_taxonomy_info(struct hostapd_iface *iface, const u8 *addr,
+				   struct wpabuf **probe_ie_taxonomy);
 
 #endif /* BEACON_H */

src/ap/hostapd.c

@@ -374,7 +374,7 @@ static void sta_track_deinit(struct hostapd_iface *iface)
 				     list))) {
 		dl_list_del(&info->list);
 		iface->num_sta_seen--;
-		os_free(info);
+		sta_track_del(info);
 	}
 }
 

src/ap/hostapd.h

@@ -311,6 +311,9 @@ struct hostapd_sta_info {
 	struct dl_list list;
 	u8 addr[ETH_ALEN];
 	struct os_reltime last_seen;
+#ifdef CONFIG_TAXONOMY
+	struct wpabuf *probe_ie_taxonomy;
+#endif /* CONFIG_TAXONOMY */
 };
 
 /**

src/ap/sta_info.c

@@ -667,6 +667,11 @@ struct sta_info * ap_sta_add(struct hostapd_data *hapd, const u8 *addr)
 	sta->last_seq_ctrl = WLAN_INVALID_MGMT_SEQ;
 	dl_list_init(&sta->ip6addr);
 
+#ifdef CONFIG_TAXONOMY
+	sta_track_claim_taxonomy_info(hapd->iface, addr,
+				      &sta->probe_ie_taxonomy);
+#endif /* CONFIG_TAXONOMY */
+
 	return sta;
 }
 

src/ap/taxonomy.c

@@ -273,6 +273,15 @@ void taxonomy_sta_info_probe_req(const struct hostapd_data *hapd,
 }
 
 
+void taxonomy_hostapd_sta_info_probe_req(const struct hostapd_data *hapd,
+					 struct hostapd_sta_info *info,
+					 const u8 *ie, size_t ie_len)
+{
+	wpabuf_free(info->probe_ie_taxonomy);
+	info->probe_ie_taxonomy = wpabuf_alloc_copy(ie, ie_len);
+}
+
+
 void taxonomy_sta_info_assoc_req(const struct hostapd_data *hapd,
 				 struct sta_info *sta,
 				 const u8 *ie, size_t ie_len)

src/ap/taxonomy.h

@@ -12,6 +12,9 @@
 void taxonomy_sta_info_probe_req(const struct hostapd_data *hapd,
 				 struct sta_info *sta,
 				 const u8 *ie, size_t ie_len);
+void taxonomy_hostapd_sta_info_probe_req(const struct hostapd_data *hapd,
+					 struct hostapd_sta_info *sta,
+					 const u8 *ie, size_t ie_len);
 void taxonomy_sta_info_assoc_req(const struct hostapd_data *hapd,
 				 struct sta_info *sta,
 				 const u8 *ie, size_t ie_len);