document recent changes.

provided by Peter Postma.  PR/26068
mdoc tweaks by me.

share/man/man9/pfil.9

@@ -1,4 +1,4 @@
-.\"	$NetBSD: pfil.9,v 1.24 2004/01/01 15:24:35 wiz Exp $
+.\"	$NetBSD: pfil.9,v 1.25 2004/07/25 23:10:49 yamt Exp $
 .\"
 .\" Copyright (c) 1996 Matthew R. Green
 .\" All rights reserved.
@@ -26,7 +26,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd January 1, 2004
+.Dd July 26, 2004
 .Dt PFIL 9
 .Os
 .Sh NAME
@@ -103,8 +103,11 @@ When a filter is invoked, the packet appears just as if it
 That is, all protocol fields are in network byte order.
 The filter is called with its specified argument, the pointer to the
 pointer to the mbuf containing the packet, the pointer to the network
-interface that the packet is traversing, and the direction (PFIL_IN
-or PFIL_OUT) that the packet is traveling.
+interface that the packet is traversing, and the direction (
+.Dv PFIL_IN
+or
+.Dv PFIL_OUT ,
+see also below) that the packet is traveling.
 The filter may change which mbuf the mbuf ** argument references.
 The filter returns an errno if the packet processing is to stop, or 0
 if the processing is to continue.
@@ -112,6 +115,29 @@ If the packet processing is to stop, it is the responsibility of the
 filter to free the packet.
 .Pp
 The
+.Em flags
+parameter, used in the
+.Fn pfil_add_hook
+and
+.Fn pfil_remove_hook
+functions, indicates when the filter should be called.
+The flags are:
+.Bl  -tag -offset indent -width PFIL_WAITOK -compact
+.It PFIL_IN
+call me on incoming packets
+.It PFIL_OUT
+call me on outgoing packets
+.It PFIL_ALL
+call me on all of the above
+.It PFIL_IFADDR
+call me on interface reconfig (mbuf ** is ioctl #)
+.It PFIL_NEWIF
+call me on interface creation (mbuf ** is ignored)
+.It PFIL_WAITOK
+OK to call malloc with M_WAITOK.
+.El
+.Pp
+The
 .Nm
 interface is enabled in the kernel via the
 .Sy PFIL_HOOKS