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>

1 files changed, 128 insertions, 7 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7f2739a90bdb..c077de7fbd8a 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2063,15 +2063,29 @@ struct cfg80211_bss {
 };
 
 /**
+ * ieee80211_bss_get_elem - find element with given ID
+ * @bss: the bss to search
+ * @id: the element ID
+ *
+ * Note that the return value is an RCU-protected pointer, so
+ * rcu_read_lock() must be held when calling this function.
+ * Return: %NULL if not found.
+ */
+const struct element *ieee80211_bss_get_elem(struct cfg80211_bss *bss, u8 id);
+
+/**
  * ieee80211_bss_get_ie - find IE with given ID
  * @bss: the bss to search
- * @ie: the IE ID
+ * @id: the element ID
  *
  * Note that the return value is an RCU-protected pointer, so
  * rcu_read_lock() must be held when calling this function.
  * Return: %NULL if not found.
  */
-const u8 *ieee80211_bss_get_ie(struct cfg80211_bss *bss, u8 ie);
+static inline const u8 *ieee80211_bss_get_ie(struct cfg80211_bss *bss, u8 id)
+{
+	return (void *)ieee80211_bss_get_elem(bss, id);
+}
 
 
 /**
@@ -5000,6 +5014,33 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb,
 				    struct cfg80211_qos_map *qos_map);
 
 /**
+ * cfg80211_find_elem_match - match information element and byte array in data
+ *
+ * @eid: element ID
+ * @ies: data consisting of IEs
+ * @len: length of data
+ * @match: byte array to match
+ * @match_len: number of bytes in the match array
+ * @match_offset: offset in the IE data where the byte array should match.
+ *	Note the difference to cfg80211_find_ie_match() which considers
+ *	the offset to start from the element ID byte, but here we take
+ *	the data portion instead.
+ *
+ * Return: %NULL if the element ID could not be found or if
+ * the element is invalid (claims to be longer than the given
+ * data) or if the byte array doesn't match; otherwise return the
+ * requested element struct.
+ *
+ * Note: There are no checks on the element length other than
+ * having to fit into the given data and being large enough for the
+ * byte array to match.
+ */
+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);
+
+/**
  * cfg80211_find_ie_match - match information element and byte array in data
  *
  * @eid: element ID
@@ -5023,9 +5064,44 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb,
  * having to fit into the given data and being large enough for the
  * byte array to match.
  */
-const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len,
-				 const u8 *match, int match_len,
-				 int match_offset);
+static inline const u8 *
+cfg80211_find_ie_match(u8 eid, const u8 *ies, unsigned int len,
+		       const u8 *match, unsigned int match_len,
+		       unsigned int match_offset)
+{
+	/* 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;
+
+	return (void *)cfg80211_find_elem_match(eid, ies, len,
+						match, match_len,
+						match_offset ?
+							match_offset - 2 : 0);
+}
+
+/**
+ * cfg80211_find_elem - find information element in data
+ *
+ * @eid: element ID
+ * @ies: data consisting of IEs
+ * @len: length of data
+ *
+ * Return: %NULL if the element ID could not be found or if
+ * the element is invalid (claims to be longer than the given
+ * data) or if the byte array doesn't match; otherwise return the
+ * requested element struct.
+ *
+ * Note: There are no checks on the element length other than
+ * having to fit into the given data.
+ */
+static inline const struct element *
+cfg80211_find_elem(u8 eid, const u8 *ies, int len)
+{
+	return cfg80211_find_elem_match(eid, ies, len, NULL, 0, 0);
+}
 
 /**
  * cfg80211_find_ie - find information element in data
@@ -5048,6 +5124,28 @@ static inline const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len)
 }
 
 /**
+ * cfg80211_find_ext_elem - find information element with EID Extension in data
+ *
+ * @ext_eid: element ID Extension
+ * @ies: data consisting of IEs
+ * @len: length of data
+ *
+ * Return: %NULL if the etended element could not be found or if
+ * the element is invalid (claims to be longer than the given
+ * data) or if the byte array doesn't match; otherwise return the
+ * requested element struct.
+ *
+ * Note: There are no checks on the element length other than
+ * having to fit into the given data.
+ */
+static inline const struct element *
+cfg80211_find_ext_elem(u8 ext_eid, const u8 *ies, int len)
+{
+	return cfg80211_find_elem_match(WLAN_EID_EXTENSION, ies, len,
+					&ext_eid, 1, 0);
+}
+
+/**
  * cfg80211_find_ext_ie - find information element with EID Extension in data
  *
  * @ext_eid: element ID Extension
@@ -5069,6 +5167,25 @@ static inline const u8 *cfg80211_find_ext_ie(u8 ext_eid, const u8 *ies, int len)
 }
 
 /**
+ * cfg80211_find_vendor_elem - find vendor specific information element in data
+ *
+ * @oui: vendor OUI
+ * @oui_type: vendor-specific OUI type (must be < 0xff), negative means any
+ * @ies: data consisting of IEs
+ * @len: length of data
+ *
+ * Return: %NULL if the vendor specific element ID could not be found or if the
+ * element is invalid (claims to be longer than the given data); otherwise
+ * return the element structure for the requested element.
+ *
+ * Note: There are no checks on the element length other than having to fit into
+ * the given data.
+ */
+const struct element *cfg80211_find_vendor_elem(unsigned int oui, int oui_type,
+						const u8 *ies,
+						unsigned int len);
+
+/**
  * cfg80211_find_vendor_ie - find vendor specific information element in data
  *
  * @oui: vendor OUI
@@ -5084,8 +5201,12 @@ static inline const u8 *cfg80211_find_ext_ie(u8 ext_eid, const u8 *ies, int len)
  * Note: There are no checks on the element length other than having to fit into
  * the given data.
  */
-const u8 *cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
-				  const u8 *ies, int len);
+static inline const u8 *
+cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
+			const u8 *ies, unsigned int len)
+{
+	return (void *)cfg80211_find_vendor_elem(oui, oui_type, ies, len);
+}
 
 /**
  * cfg80211_send_layer2_update - send layer 2 update frame