cfg80211: add various struct element finding helpers

We currently have a number of helpers to find elements that just
return a u8 *, change those to return a struct element and add
inlines to deal with the u8 * compatibility.

Note that the match behaviour is changed to start the natch at
the data, so conversion from _ie_match to _elem_match need to
be done carefully.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 20 insertions, 25 deletions

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index c7f64bb9c581..d2c9ca5f4f57 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -480,48 +480,43 @@ void cfg80211_bss_expire(struct cfg80211_registered_device *rdev)
 	__cfg80211_bss_expire(rdev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
 }
 
-const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len,
-				 const u8 *match, int match_len,
-				 int match_offset)
+const struct element *
+cfg80211_find_elem_match(u8 eid, const u8 *ies, unsigned int len,
+			 const u8 *match, unsigned int match_len,
+			 unsigned int match_offset)
 {
 	const struct element *elem;
 
-	/* match_offset can't be smaller than 2, unless match_len is
-	 * zero, in which case match_offset must be zero as well.
-	 */
-	if (WARN_ON((match_len && match_offset < 2) ||
-		    (!match_len && match_offset)))
-		return NULL;
-
 	for_each_element_id(elem, eid, ies, len) {
-		if (elem->datalen >= match_offset - 2 + match_len &&
-		    !memcmp(elem->data + match_offset - 2, match, match_len))
-			return (void *)elem;
+		if (elem->datalen >= match_offset + match_len &&
+		    !memcmp(elem->data + match_offset, match, match_len))
+			return elem;
 	}
 
 	return NULL;
 }
-EXPORT_SYMBOL(cfg80211_find_ie_match);
+EXPORT_SYMBOL(cfg80211_find_elem_match);
 
-const u8 *cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
-				  const u8 *ies, int len)
+const struct element *cfg80211_find_vendor_elem(unsigned int oui, int oui_type,
+						const u8 *ies,
+						unsigned int len)
 {
-	const u8 *ie;
+	const struct element *elem;
 	u8 match[] = { oui >> 16, oui >> 8, oui, oui_type };
 	int match_len = (oui_type < 0) ? 3 : sizeof(match);
 
 	if (WARN_ON(oui_type > 0xff))
 		return NULL;
 
-	ie = cfg80211_find_ie_match(WLAN_EID_VENDOR_SPECIFIC, ies, len,
-				    match, match_len, 2);
+	elem = cfg80211_find_elem_match(WLAN_EID_VENDOR_SPECIFIC, ies, len,
+					match, match_len, 0);
 
-	if (ie && (ie[1] < 4))
+	if (!elem || elem->datalen < 4)
 		return NULL;
 
-	return ie;
+	return elem;
 }
-EXPORT_SYMBOL(cfg80211_find_vendor_ie);
+EXPORT_SYMBOL(cfg80211_find_vendor_elem);
 
 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 		   const u8 *ssid, size_t ssid_len)
diff --git a/net/wireless/util.c b/net/wireless/util.c
index cd48cdd582c0..61fa33d0019e 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -776,7 +776,7 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb,
 }
 EXPORT_SYMBOL(cfg80211_classify8021d);
 
-const u8 *ieee80211_bss_get_ie(struct cfg80211_bss *bss, u8 ie)
+const struct element *ieee80211_bss_get_elem(struct cfg80211_bss *bss, u8 id)
 {
 	const struct cfg80211_bss_ies *ies;
 
@@ -784,9 +784,9 @@ const u8 *ieee80211_bss_get_ie(struct cfg80211_bss *bss, u8 ie)
 	if (!ies)
 		return NULL;
 
-	return cfg80211_find_ie(ie, ies->data, ies->len);
+	return cfg80211_find_elem(id, ies->data, ies->len);
 }
-EXPORT_SYMBOL(ieee80211_bss_get_ie);
+EXPORT_SYMBOL(ieee80211_bss_get_elem);
 
 void cfg80211_upload_connect_keys(struct wireless_dev *wdev)
 {