MLD: Support multiple RNR elements

Beacon frames are allowed to optionally include one more more Reduced
Neighbor Report elements. Only the first one was parsed previously.
Extend this to use a loop to go through all included RNR elements.

Signed-off-by: Ben Greear <greearb@candelatech.com>

src/common/ieee802_11_common.c

@@ -2495,6 +2495,35 @@ const u8 * get_ie(const u8 *ies, size_t len, u8 eid)
 }
 
 
+/**
+ * get_ie_nth - Fetch a specified information element from IEs buffer
+ * @ies: Information elements buffer
+ * @len: Information elements buffer length
+ * @eid: Information element identifier (WLAN_EID_*)
+ * @nth: Return the nth element of the requested type (2 returns the second)
+ * Returns: Pointer to the information element (id field) or %NULL if not found
+ *
+ * This function returns the nth matching information element in the IEs
+ * buffer or %NULL in case the element is not found.
+ */
+const u8 * get_ie_nth(const u8 *ies, size_t len, u8 eid, int nth)
+{
+	const struct element *elem;
+	int sofar = 0;
+
+	if (!ies)
+		return NULL;
+
+	for_each_element_id(elem, eid, ies, len) {
+		sofar++;
+		if (sofar == nth)
+			return &elem->id;
+	}
+
+	return NULL;
+}
+
+
 /**
  * get_ie_ext - Fetch a specified extended information element from IEs buffer
  * @ies: Information elements buffer

src/common/ieee802_11_common.h

@@ -261,6 +261,7 @@ extern const struct oper_class_map global_op_class[];
 extern size_t global_op_class_size;
 
 const u8 * get_ie(const u8 *ies, size_t len, u8 eid);
+const u8 * get_ie_nth(const u8 *ies, size_t len, u8 eid, int nth);
 const u8 * get_ie_ext(const u8 *ies, size_t len, u8 ext);
 const u8 * get_vendor_ie(const u8 *ies, size_t len, u32 vendor_type);
 

wpa_supplicant/bss.c

@@ -1220,6 +1220,22 @@ const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie)
 }
 
 
+/**
+ * wpa_bss_get_ie_nth - Fetch a specified information element from a BSS entry
+ * @bss: BSS table entry
+ * @ie: Information element identitifier (WLAN_EID_*)
+ * @nth: Return the nth element of the requested type (2 returns the second)
+ * Returns: Pointer to the information element (id field) or %NULL if not found
+ *
+ * This function returns the nth matching information element in the BSS
+ * entry.
+ */
+const u8 * wpa_bss_get_ie_nth(const struct wpa_bss *bss, u8 ie, int nth)
+{
+	return get_ie_nth(wpa_bss_ie_ptr(bss), bss->ie_len, ie, nth);
+}
+
+
 /**
  * wpa_bss_get_ie_ext - Fetch a specified extended IE from a BSS entry
  * @bss: BSS table entry

wpa_supplicant/bss.h

@@ -169,6 +169,7 @@ struct wpa_bss * wpa_bss_get_id(struct wpa_supplicant *wpa_s, unsigned int id);
 struct wpa_bss * wpa_bss_get_id_range(struct wpa_supplicant *wpa_s,
 				      unsigned int idf, unsigned int idl);
 const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie);
+const u8 * wpa_bss_get_ie_nth(const struct wpa_bss *bss, u8 ie, int nth);
 const u8 * wpa_bss_get_ie_ext(const struct wpa_bss *bss, u8 ext);
 const u8 * wpa_bss_get_vendor_ie(const struct wpa_bss *bss, u32 vendor_type);
 const u8 * wpa_bss_get_vendor_ie_beacon(const struct wpa_bss *bss,

wpa_supplicant/sme.c

@@ -454,6 +454,7 @@ static bool wpas_ml_element(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 			     BASIC_MULTI_LINK_CTRL_PRES_BSS_PARAM_CH_COUNT |
 			     BASIC_MULTI_LINK_CTRL_PRES_MLD_CAPA);
 	bool ret = false;
+	int rnr_idx;
 
 	if (!(wpa_s->drv_flags2 & WPA_DRIVER_FLAGS2_MLO))
 		return false;
@@ -519,14 +520,23 @@ static bool wpas_ml_element(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 
 	wpa_s->valid_links = BIT(wpa_s->mlo_assoc_link_id);
 
-	rnr_ie = wpa_bss_get_ie(bss, WLAN_EID_REDUCED_NEIGHBOR_REPORT);
-	if (!rnr_ie) {
-		wpa_dbg(wpa_s, MSG_DEBUG, "MLD: No RNR element");
 	ret = true;
+
+	/* Process all Reduced Neighbor Report elements */
+	for (rnr_idx = 1; ; rnr_idx++) {
+		rnr_ie = wpa_bss_get_ie_nth(bss,
+					    WLAN_EID_REDUCED_NEIGHBOR_REPORT,
+					    rnr_idx);
+		if (!rnr_ie) {
+			if (rnr_idx == 0) {
+				wpa_dbg(wpa_s, MSG_DEBUG,
+					"MLD: No RNR element");
 				goto out;
 			}
-
+			break;
+		}
 		wpas_process_rnr(wpa_s, rnr_ie + 2, rnr_ie[1]);
+	}
 
 	wpa_printf(MSG_DEBUG, "MLD: valid_links=0x%x", wpa_s->valid_links);
 
@@ -538,7 +548,6 @@ static bool wpas_ml_element(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 			   i, MAC2STR(wpa_s->links[i].bssid));
 	}
 
-	ret = true;
 out:
 	wpabuf_free(mlbuf);
 	return ret;