Overhaul monitor mode handling:

o replace DLT_IEEE802_11 support in net80211 with DLT_IEEE802_11_RADIO
  and remove explicit bpf support from wireless drivers; drivers now
  use ieee80211_radiotap_attach to setup shared data structures that
  hold the radiotap header for each packet tx/rx
o remove rx timestamp from the rx path; it was used only by the tdma support
  for debugging and was mostly useless due to it being 32-bits and mostly
  unavailable
o track DLT_IEEE80211_RADIO bpf attachments and maintain per-vap and
  per-com state when there are active taps
o track the number of monitor mode vaps
o use bpf tap and monitor mode vap state to decide when to collect radiotap
  state and dispatch frames; drivers no longer explicitly directly check
  bpf state or use bpf calls to tap frames
o handle radiotap state updates on channel change in net80211; drivers
  should not do this (unless they bypass net80211 which is almost always
  a mistake)
o update various drivers to be more consistent/correct in handling radiotap
o update ral to include TSF in radiotap'd frames
o add promisc mode callback to wi

Reviewed by:	cbzimmer, rpaulo, thompsa

1 files changed, 29 insertions, 0 deletions

diff --git a/sys/net80211/ieee80211_freebsd.c b/sys/net80211/ieee80211_freebsd.c
index e96e71d..89292a6 100644
--- a/sys/net80211/ieee80211_freebsd.c
+++ b/sys/net80211/ieee80211_freebsd.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/socket.h>
 #include <sys/vimage.h>
 
+#include <net/bpf.h>
 #include <net/if.h>
 #include <net/if_dl.h>
 #include <net/if_clone.h>
@@ -726,6 +727,29 @@ ieee80211_load_module(const char *modname)
 #endif
 }
 
+static eventhandler_tag wlan_bpfevent;
+
+static void
+bpf_track(void *arg, struct ifnet *ifp, int attach)
+{
+	/* NB: identify vap's by if_start */
+	if (ifp->if_start == ieee80211_start) {
+		struct ieee80211vap *vap = ifp->if_softc;
+		/*
+		 * Track bpf radiotap listener state.  We mark the vap
+		 * to indicate if any listener is present and the com
+		 * to indicate if any listener exists on any associated
+		 * vap.  This flag is used by drivers to prepare radiotap
+		 * state only when needed.
+		 */
+		if (attach)
+			ieee80211_syncflag_ext(vap, IEEE80211_FEXT_BPF);
+		/* NB: if_softc is NULL on vap detach */
+		else if (vap != NULL && !bpf_peers_present(vap->iv_rawbpf))
+			ieee80211_syncflag_ext(vap, -IEEE80211_FEXT_BPF);
+	}
+}
+
 /*
  * Module glue.
  *
@@ -738,12 +762,17 @@ wlan_modevent(module_t mod, int type, void *unused)
 	case MOD_LOAD:
 		if (bootverbose)
 			printf("wlan: <802.11 Link Layer>\n");
+		wlan_bpfevent = EVENTHANDLER_REGISTER(bpf_track,
+		    bpf_track, 0, EVENTHANDLER_PRI_ANY);
+		if (wlan_bpfevent == NULL)
+			return ENOMEM;
 		if_clone_attach(&wlan_cloner);
 		if_register_com_alloc(IFT_IEEE80211, wlan_alloc, wlan_free);
 		return 0;
 	case MOD_UNLOAD:
 		if_deregister_com_alloc(IFT_IEEE80211);
 		if_clone_detach(&wlan_cloner);
+		EVENTHANDLER_DEREGISTER(bpf_track, wlan_bpfevent);
 		return 0;
 	}
 	return EINVAL;