Lock down the network interface queues. The queue mutex must be obtained

before adding/removing packets from the queue.  Also, the if_obytes and
if_omcasts fields should only be manipulated under protection of the mutex.

IF_ENQUEUE, IF_PREPEND, and IF_DEQUEUE perform all necessary locking on
the queue.  An IF_LOCK macro is provided, as well as the old (mutex-less)
versions of the macros in the form _IF_ENQUEUE, _IF_QFULL, for code which
needs them, but their use is discouraged.

Two new macros are introduced: IF_DRAIN() to drain a queue, and IF_HANDOFF,
which takes care of locking/enqueue, and also statistics updating/start
if necessary.

2 files changed, 3 insertions, 10 deletions

diff --git a/sys/netipx/ipx_input.c b/sys/netipx/ipx_input.c
index e16285c..dc4a1a3 100644
--- a/sys/netipx/ipx_input.c
+++ b/sys/netipx/ipx_input.c
@@ -107,6 +107,7 @@ ipx_init()
 
 	read_random(&ipx_pexseq, sizeof ipx_pexseq);
 	ipxintrq.ifq_maxlen = ipxqmaxlen;
+	mtx_init(&ipxintrq.ifq_mtx, "ipx_inq", MTX_DEF);
 	ipxpcb.ipxp_next = ipxpcb.ipxp_prev = &ipxpcb;
 	ipxrawpcb.ipxp_next = ipxrawpcb.ipxp_prev = &ipxrawpcb;
 
diff --git a/sys/netipx/ipx_ip.c b/sys/netipx/ipx_ip.c
index 7abd9da..9062d3b 100644
--- a/sys/netipx/ipx_ip.c
+++ b/sys/netipx/ipx_ip.c
@@ -225,16 +225,8 @@ ipxip_input(m, hlen)
 	/*
 	 * Deliver to IPX
 	 */
-	s = splimp();
-	if (IF_QFULL(ifq)) {
-		IF_DROP(ifq);
-		m_freem(m);
-		splx(s);
-		return;
-	}
-	IF_ENQUEUE(ifq, m);
-	schednetisr(NETISR_IPX);
-	splx(s);
+	if (IF_HANDOFF(ifq, m, NULL))
+		schednetisr(NETISR_IPX);
 	return;
 }