fix monitor mode related crash in madwifi (#2034)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@7957 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/madwifi/patches/126-rxerr_frames.patch

@@ -0,0 +1,15 @@
+Index: madwifi-ng-r2568-20070710/ath/if_ath.c
+===================================================================
+--- madwifi-ng-r2568-20070710.orig/ath/if_ath.c	2007-07-13 09:14:14.721154018 +0200
++++ madwifi-ng-r2568-20070710/ath/if_ath.c	2007-07-13 09:14:55.499477843 +0200
+@@ -5711,8 +5711,9 @@
+ 			/*
+ 			 * Reject error frames if we have no vaps that 
+ 			 * are operating in monitor mode.
++			 * Reject empty frames as well
+ 			 */
+-			if (sc->sc_nmonvaps == 0)
++			if ((sc->sc_nmonvaps == 0) || (rs->rs_datalen == 0))
+ 				goto rx_next;
+ 		}
+ rx_accept: