Add BSS list sorted by id and add some helper functions

This allows the BSS list to be iterated in order of increasing id
to avoid problems with new scans reordering entries. The order on the
wpa_s->bss list changes with most recently updated entries being moved
to the tail of the list while wpa_s->bss_id list maintains its order
with new entries being added to the tail and old entries being removed
when they expire.

wpa_supplicant/bss.c

@@ -55,6 +55,7 @@
 static void wpa_bss_remove(struct wpa_supplicant *wpa_s, struct wpa_bss *bss)
 {
 	dl_list_del(&bss->list);
+	dl_list_del(&bss->list_id);
 	wpa_s->num_bss--;
 	wpa_printf(MSG_DEBUG, "BSS: Remove id %u BSSID " MACSTR " SSID '%s'",
 		   bss->id, MAC2STR(bss->bssid),
@@ -122,6 +123,7 @@ static void wpa_bss_add(struct wpa_supplicant *wpa_s,
 	os_memcpy(bss + 1, res + 1, res->ie_len);
 
 	dl_list_add_tail(&wpa_s->bss, &bss->list);
+	dl_list_add_tail(&wpa_s->bss_id, &bss->list_id);
 	wpa_s->num_bss++;
 	wpa_printf(MSG_DEBUG, "BSS: Add new id %u BSSID " MACSTR " SSID '%s'",
 		   bss->id, MAC2STR(bss->bssid), wpa_ssid_txt(ssid, ssid_len));
@@ -247,6 +249,7 @@ static void wpa_bss_timeout(void *eloop_ctx, void *timeout_ctx)
 int wpa_bss_init(struct wpa_supplicant *wpa_s)
 {
 	dl_list_init(&wpa_s->bss);
+	dl_list_init(&wpa_s->bss_id);
 	eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
 			       wpa_bss_timeout, wpa_s, NULL);
 	return 0;
@@ -260,3 +263,96 @@ void wpa_bss_deinit(struct wpa_supplicant *wpa_s)
 	dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list)
 		wpa_bss_remove(wpa_s, bss);
 }
+
+
+struct wpa_bss * wpa_bss_get_bssid(struct wpa_supplicant *wpa_s,
+				   const u8 *bssid)
+{
+	struct wpa_bss *bss;
+	dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
+		if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
+			return bss;
+	}
+	return NULL;
+}
+
+
+struct wpa_bss * wpa_bss_get_id(struct wpa_supplicant *wpa_s, unsigned int id)
+{
+	struct wpa_bss *bss;
+	dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
+		if (bss->id == id)
+			return bss;
+	}
+	return NULL;
+}
+
+
+const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie)
+{
+	const u8 *end, *pos;
+
+	pos = (const u8 *) (bss + 1);
+	end = pos + bss->ie_len;
+
+	while (pos + 1 < end) {
+		if (pos + 2 + pos[1] > end)
+			break;
+		if (pos[0] == ie)
+			return pos;
+		pos += 2 + pos[1];
+	}
+
+	return NULL;
+}
+
+
+const u8 * wpa_bss_get_vendor_ie(const struct wpa_bss *bss, u32 vendor_type)
+{
+	const u8 *end, *pos;
+
+	pos = (const u8 *) (bss + 1);
+	end = pos + bss->ie_len;
+
+	while (pos + 1 < end) {
+		if (pos + 2 + pos[1] > end)
+			break;
+		if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
+		    vendor_type == WPA_GET_BE32(&pos[2]))
+			return pos;
+		pos += 2 + pos[1];
+	}
+
+	return NULL;
+}
+
+
+struct wpabuf * wpa_bss_get_vendor_ie_multi(const struct wpa_bss *bss,
+					    u32 vendor_type)
+{
+	struct wpabuf *buf;
+	const u8 *end, *pos;
+
+	buf = wpabuf_alloc(bss->ie_len);
+	if (buf == NULL)
+		return NULL;
+
+	pos = (const u8 *) (bss + 1);
+	end = pos + bss->ie_len;
+
+	while (pos + 1 < end) {
+		if (pos + 2 + pos[1] > end)
+			break;
+		if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
+		    vendor_type == WPA_GET_BE32(&pos[2]))
+			wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
+		pos += 2 + pos[1];
+	}
+
+	if (wpabuf_len(buf) == 0) {
+		wpabuf_free(buf);
+		buf = NULL;
+	}
+
+	return buf;
+}

wpa_supplicant/bss.h

@@ -25,6 +25,7 @@
 /**
  * struct wpa_bss - BSS table
  * @list: List entry for struct wpa_supplicant::bss
+ * @list_id: List entry for struct wpa_supplicant::bss_id
  * @id: Unique identifier for this BSS entry
  * @scan_miss_count: Number of counts without seeing this BSS
  * @flags: information flags about the BSS/IBSS (WPA_BSS_*)
@@ -45,6 +46,7 @@
  */
 struct wpa_bss {
 	struct dl_list list;
+	struct dl_list list_id;
 	unsigned int id;
 	unsigned int scan_miss_count;
 	unsigned int last_update_idx;
@@ -70,5 +72,12 @@ void wpa_bss_update_scan_res(struct wpa_supplicant *wpa_s,
 void wpa_bss_update_end(struct wpa_supplicant *wpa_s);
 int wpa_bss_init(struct wpa_supplicant *wpa_s);
 void wpa_bss_deinit(struct wpa_supplicant *wpa_s);
+struct wpa_bss * wpa_bss_get_bssid(struct wpa_supplicant *wpa_s,
+				   const u8 *bssid);
+struct wpa_bss * wpa_bss_get_id(struct wpa_supplicant *wpa_s, unsigned int id);
+const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie);
+const u8 * wpa_bss_get_vendor_ie(const struct wpa_bss *bss, u32 vendor_type);
+struct wpabuf * wpa_bss_get_vendor_ie_multi(const struct wpa_bss *bss,
+					    u32 vendor_type);
 
 #endif /* BSS_H */

wpa_supplicant/wpa_supplicant_i.h

@@ -346,6 +346,7 @@ struct wpa_supplicant {
 
 	struct wpa_scan_results *scan_res;
 	struct dl_list bss; /* struct wpa_bss::list */
+	struct dl_list bss_id; /* struct wpa_bss::list_id */
 	size_t num_bss;
 	unsigned int bss_update_idx;
 	unsigned int bss_next_id;