o eliminate widespread on-stack mbuf use for bpf by introducing

  a new bpf_mtap2 routine that does the right thing for an mbuf
  and a variable-length chunk of data that should be prepended.
o while we're sweeping the drivers, use u_int32_t uniformly when
  when prepending the address family (several places were assuming
  sizeof(int) was 4)
o return M_ASSERTVALID to BPF_MTAP* now that all stack-allocated
  mbufs have been eliminated; this may better be moved to the bpf
  routines

Reviewed by:	arch@ and several others

1 files changed, 2 insertions, 8 deletions

diff --git a/sys/netgraph/ng_iface.c b/sys/netgraph/ng_iface.c
index ca637e7..430e0e6 100644
--- a/sys/netgraph/ng_iface.c
+++ b/sys/netgraph/ng_iface.c
@@ -485,16 +485,10 @@ ng_iface_start(struct ifnet *ifp)
 static void
 ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
 {
-	int32_t family4 = (int32_t)family;
-	struct mbuf m0;
-
 	KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
 	if (ifp->if_bpf != NULL) {
-		bzero(&m0, sizeof(m0));
-		m0.m_next = m;
-		m0.m_len = sizeof(family4);
-		m0.m_data = (char *)&family4;
-		BPF_MTAP(ifp, &m0);
+		int32_t family4 = (int32_t)family;
+		bpf_mtap2(ifp->if_bpf, &family4, sizeof(family4), m);
 	}
 }