From 0f3b07f027f87a38ebe5c436490095df762819be Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 7 Feb 2019 21:44:41 +0100 Subject: cfg80211: add and use strongly typed element iteration macros Rather than always iterating elements from frames with pure u8 pointers, add a type "struct element" that encapsulates the id/datalen/data format of them. Then, add the element iteration macros * for_each_element * for_each_element_id * for_each_element_extid which take, as their first 'argument', such a structure and iterate through a given u8 array interpreting it as elements. While at it and since we'll need it, also add * for_each_subelement * for_each_subelement_id * for_each_subelement_extid which instead of taking data/length just take an outer element and use its data/datalen. Also add for_each_element_completed() to determine if any of the loops above completed, i.e. it was able to parse all of the elements successfully and no data remained. Use for_each_element_id() in cfg80211_find_ie_match() as the first user of this. Signed-off-by: Johannes Berg --- net/wireless/scan.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'net') diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 5123667f4569..c7f64bb9c581 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -484,6 +484,8 @@ 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 *elem; + /* match_offset can't be smaller than 2, unless match_len is * zero, in which case match_offset must be zero as well. */ @@ -491,14 +493,10 @@ const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len, (!match_len && match_offset))) return NULL; - while (len >= 2 && len >= ies[1] + 2) { - if ((ies[0] == eid) && - (ies[1] + 2 >= match_offset + match_len) && - !memcmp(ies + match_offset, match, match_len)) - return ies; - - len -= ies[1] + 2; - ies += ies[1] + 2; + 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; } return NULL; -- cgit v1.2.3