MFp4 changes to fix locking issues and correct reference

count handling of station entries in hostap mode:

Input path:

o driver is now expected to find the node associated with the
  sender of a received frame; use ic_bss if none is located
o driver passes the (referenced) node into ieee80211_input for
  use within the wlan module and is responsible for cleaning up
  on return
o the antenna state is no longer passed up with each frame; this
  is now considered driver-private state and drivers are responsible
  for keeping it in the driver-private part of a node

Output path:

Revamp output path for management frames to eliminate redundant
locking that causes problems and to correct reference counting
bogosity that occurs when stations are timed out due to inactivity
(in AP mode).  On output the refcnt'd node is stashed in the pkthdr's
recvif field (yech) and retrieved by the driver.  This eliminates
an unref/ref scenario and related node table unlock/lock due to the
driver looking up the node.  This is particularly important when
stations are timed out as this causes a lock order reversal that
can result in a deadlock.  As a byproduct we also reduce the overhead
for sending management frames (minimal).  Additional fallout from
this is a change to ieee80211_encap to return a refcn't node for
tieing to the outbound frame.  Node refcnts are not reclaimed until
after a frame is completely processed (e.g. in the tx interrupt
handler).  This is especially important for timed out stations as
this deref will be the final one causing the node entry to be
reclaimed.

Additional semi-related changes:
o replace m_copym use with m_copypacket (optimization)
o add assert to verify ic_bss is never free'd during normal operation
o add comments explaining calling conventions by drivers for frames
  going in each direction
o remove extraneous code that "cannot be executed" (e.g. because
  pointers may never be null)

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index af47773..187ab79 100644
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -135,7 +135,8 @@ struct ieee80211_channel {
 struct ieee80211com {
 	struct arpcom		ic_ac;
 	void			(*ic_recv_mgmt)(struct ieee80211com *,
-				    struct mbuf *, int, int, u_int32_t, u_int);
+				    struct mbuf *, struct ieee80211_node *,
+				    int, int, u_int32_t);
 	int			(*ic_send_mgmt)(struct ieee80211com *,
 				    struct ieee80211_node *, int, int);
 	int			(*ic_newstate)(struct ieee80211com *,