utils: Share a single helper function to get IE by ID

Add a helper function to find a certain IE inside IEs buffer by ID and
use this function in several places that implemented similar
functionality locally.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>

src/common/ieee802_11_common.c

@@ -1172,3 +1172,36 @@ struct wpabuf * mb_ies_by_info(struct mb_ies_info *info)
 
 	return mb_ies;
 }
+
+
+/**
+ * get_ie - Fetch a specified information element from IEs buffer
+ * @ies: Information elements buffer
+ * @len: Information elements buffer length
+ * @eid: Information element identifier (WLAN_EID_*)
+ * Returns: Pointer to the information element (id field) or %NULL if not found
+ *
+ * This function returns the first matching information element in the IEs
+ * buffer or %NULL in case the element is not found.
+ */
+const u8 * get_ie(const u8 *ies, size_t len, u8 eid)
+{
+	const u8 *end;
+
+	if (!ies)
+		return NULL;
+
+	end = ies + len;
+
+	while (end - ies > 1) {
+		if (2 + ies[1] > end - ies)
+			break;
+
+		if (ies[0] == eid)
+			return ies;
+
+		ies += 2 + ies[1];
+	}
+
+	return NULL;
+}

src/common/ieee802_11_common.h

@@ -125,4 +125,7 @@ int mb_ies_info_by_ies(struct mb_ies_info *info, const u8 *ies_buf,
 struct wpabuf * mb_ies_by_info(struct mb_ies_info *info);
 
 const char * fc2str(u16 fc);
+
+const u8 * get_ie(const u8 *ies, size_t len, u8 eid);
+
 #endif /* IEEE802_11_COMMON_H */

src/drivers/driver_nl80211.h

@@ -285,7 +285,6 @@ int wpa_driver_nl80211_stop_sched_scan(void *priv);
 struct wpa_scan_results * wpa_driver_nl80211_get_scan_results(void *priv);
 void nl80211_dump_scan(struct wpa_driver_nl80211_data *drv);
 int wpa_driver_nl80211_abort_scan(void *priv);
-const u8 * nl80211_get_ie(const u8 *ies, size_t ies_len, u8 ie);
 int wpa_driver_nl80211_vendor_scan(struct i802_bss *bss,
 				   struct wpa_driver_scan_params *params);
 

src/drivers/driver_nl80211_event.c

@@ -335,9 +335,9 @@ static void mlme_event_connect(struct wpa_driver_nl80211_data *drv,
 		event.assoc_info.req_ies_len = nla_len(req_ie);
 
 		if (cmd == NL80211_CMD_ROAM) {
-			ssid = nl80211_get_ie(event.assoc_info.req_ies,
-					      event.assoc_info.req_ies_len,
-					      WLAN_EID_SSID);
+			ssid = get_ie(event.assoc_info.req_ies,
+				      event.assoc_info.req_ies_len,
+				      WLAN_EID_SSID);
 			if (ssid && ssid[1] > 0 && ssid[1] <= 32) {
 				drv->ssid_len = ssid[1];
 				os_memcpy(drv->ssid, ssid + 2, ssid[1]);

src/drivers/driver_nl80211_scan.c

@@ -15,6 +15,7 @@
 #include "utils/common.h"
 #include "utils/eloop.h"
 #include "common/ieee802_11_defs.h"
+#include "common/ieee802_11_common.h"
 #include "common/qca-vendor.h"
 #include "driver_nl80211.h"
 
@@ -522,28 +523,6 @@ int wpa_driver_nl80211_stop_sched_scan(void *priv)
 }
 
 
-const u8 * nl80211_get_ie(const u8 *ies, size_t ies_len, u8 ie)
-{
-	const u8 *end, *pos;
-
-	if (ies == NULL)
-		return NULL;
-
-	pos = ies;
-	end = ies + ies_len;
-
-	while (end - pos > 1) {
-		if (2 + pos[1] > end - pos)
-			break;
-		if (pos[0] == ie)
-			return pos;
-		pos += 2 + pos[1];
-	}
-
-	return NULL;
-}
-
-
 static int nl80211_scan_filtered(struct wpa_driver_nl80211_data *drv,
 				 const u8 *ie, size_t ie_len)
 {
@@ -553,7 +532,7 @@ static int nl80211_scan_filtered(struct wpa_driver_nl80211_data *drv,
 	if (drv->filter_ssids == NULL)
 		return 0;
 
-	ssid = nl80211_get_ie(ie, ie_len, WLAN_EID_SSID);
+	ssid = get_ie(ie, ie_len, WLAN_EID_SSID);
 	if (ssid == NULL)
 		return 1;
 
@@ -714,9 +693,9 @@ int bss_info_handler(struct nl_msg *msg, void *arg)
 		if (os_memcmp(res->res[i]->bssid, r->bssid, ETH_ALEN) != 0)
 			continue;
 
-		s1 = nl80211_get_ie((u8 *) (res->res[i] + 1),
-				    res->res[i]->ie_len, WLAN_EID_SSID);
-		s2 = nl80211_get_ie((u8 *) (r + 1), r->ie_len, WLAN_EID_SSID);
+		s1 = get_ie((u8 *) (res->res[i] + 1),
+			    res->res[i]->ie_len, WLAN_EID_SSID);
+		s2 = get_ie((u8 *) (r + 1), r->ie_len, WLAN_EID_SSID);
 		if (s1 == NULL || s2 == NULL || s1[1] != s2[1] ||
 		    os_memcmp(s1, s2, 2 + s1[1]) != 0)
 			continue;

wpa_supplicant/bss.c

@@ -1019,20 +1019,7 @@ struct wpa_bss * wpa_bss_get_id_range(struct wpa_supplicant *wpa_s,
  */
 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 (end - pos > 1) {
-		if (2 + pos[1] > end - pos)
-			break;
-		if (pos[0] == ie)
-			return pos;
-		pos += 2 + pos[1];
-	}
-
-	return NULL;
+	return get_ie((const u8 *) (bss + 1), bss->ie_len, ie);
 }
 
 

wpa_supplicant/scan.c

@@ -1535,20 +1535,7 @@ static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
  */
 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
 {
-	const u8 *end, *pos;
-
-	pos = (const u8 *) (res + 1);
-	end = pos + res->ie_len;
-
-	while (end - pos > 1) {
-		if (2 + pos[1] > end - pos)
-			break;
-		if (pos[0] == ie)
-			return pos;
-		pos += 2 + pos[1];
-	}
-
-	return NULL;
+	return get_ie((const u8 *) (res + 1), res->ie_len, ie);
 }