mac80211: parse VHT channel switch IEs

VHT introduces multiple IEs that need to be parsed for a
wide bandwidth channel switch. Two are (currently) needed
in mac80211:
 * wide bandwidth channel switch element
 * channel switch wrapper element

The former is contained in the latter for beacons and probe
responses, but not for the spectrum management action frames
so the IE parser needs a new argument to differentiate them.

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

1 files changed, 35 insertions, 1 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 155056c90edf..3f87fa468b1f 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -661,7 +661,7 @@ void ieee80211_queue_delayed_work(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL(ieee80211_queue_delayed_work);
 
-u32 ieee802_11_parse_elems_crc(u8 *start, size_t len,
+u32 ieee802_11_parse_elems_crc(u8 *start, size_t len, bool action,
                                struct ieee802_11_elems *elems,
                                u64 filter, u32 crc)
 {
@@ -669,6 +669,7 @@ u32 ieee802_11_parse_elems_crc(u8 *start, size_t len,
         u8 *pos = start;
         bool calc_crc = filter != 0;
         DECLARE_BITMAP(seen_elems, 256);
+        const u8 *ie;
 
         bitmap_zero(seen_elems, 256);
         memset(elems, 0, sizeof(*elems));
@@ -717,6 +718,11 @@ u32 ieee802_11_parse_elems_crc(u8 *start, size_t len,
                 case WLAN_EID_PWR_CONSTRAINT:
                 case WLAN_EID_TIMEOUT_INTERVAL:
                 case WLAN_EID_SECONDARY_CHANNEL_OFFSET:
+                case WLAN_EID_WIDE_BW_CHANNEL_SWITCH:
+                /*
+                 * not listing WLAN_EID_CHANNEL_SWITCH_WRAPPER -- it seems possible
+                 * that if the content gets bigger it might be needed more than once
+                 */
                         if (test_bit(id, seen_elems)) {
                                 elems->parse_error = true;
                                 left -= elen;
@@ -878,6 +884,34 @@ u32 ieee802_11_parse_elems_crc(u8 *start, size_t len,
                         }
                         elems->sec_chan_offs = (void *)pos;
                         break;
+                case WLAN_EID_WIDE_BW_CHANNEL_SWITCH:
+                        if (!action ||
+                            elen != sizeof(*elems->wide_bw_chansw_ie)) {
+                                elem_parse_failed = true;
+                                break;
+                        }
+                        elems->wide_bw_chansw_ie = (void *)pos;
+                        break;
+                case WLAN_EID_CHANNEL_SWITCH_WRAPPER:
+                        if (action) {
+                                elem_parse_failed = true;
+                                break;
+                        }
+                        /*
+                         * This is a bit tricky, but as we only care about
+                         * the wide bandwidth channel switch element, so
+                         * just parse it out manually.
+                         */
+                        ie = cfg80211_find_ie(WLAN_EID_WIDE_BW_CHANNEL_SWITCH,
+                                              pos, elen);
+                        if (ie) {
+                                if (ie[1] == sizeof(*elems->wide_bw_chansw_ie))
+                                        elems->wide_bw_chansw_ie =
+                                                (void *)(ie + 2);
+                                else
+                                        elem_parse_failed = true;
+                        }
+                        break;
                 case WLAN_EID_COUNTRY:
                         elems->country_elem = pos;
                         elems->country_elem_len = elen;