add short description for bpf.9

share/man/man9/Makefile

@@ -1,10 +1,10 @@
-#       $NetBSD: Makefile,v 1.305 2010/01/20 00:39:30 dyoung Exp $
+#       $NetBSD: Makefile,v 1.306 2010/01/20 12:09:39 pooka Exp $
 
 #	Makefile for section 9 (kernel function and variable) manual pages.
 
 MAN=	accept_filter.9 accf_data.9 accf_http.9 \
 	altq.9 arc4random.9 arp.9 audio.9 autoconf.9 \
-	bcdtobin.9 bcmp.9 bcopy.9 bluetooth.9 boothowto.9 \
+	bcdtobin.9 bcmp.9 bcopy.9 bluetooth.9 boothowto.9 bpf.9 \
 	buffercache.9 bufq.9 bus_dma.9 bus_space.9 byteorder.9 bzero.9 \
 	callback.9 callout.9 cardbus.9 cnmagic.9 condvar.9 config.9 \
 	cons.9 copy.9 coredump_write.9 \

share/man/man9/bpf.9

@@ -0,0 +1,75 @@
+.\"     $NetBSD: bpf.9,v 1.1 2010/01/20 12:09:39 pooka Exp $
+.\"
+.\" Copyright (c) 2010 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd January 20, 2010
+.Dt BPF 9
+.Os
+.Sh NAME
+.Nm bpf
+.Nd Berkeley Packet Filter kernel interface
+.Sh SYNOPSIS
+.In sys/mbuf.h
+.In net/bpf.h
+.Sh DESCRIPTION
+.Nm
+is called via an operations vector described by the following struct:
+.Pp
+.Bd -literal
+struct bpf_ops {
+        void (*bpf_attach)(struct ifnet *, u_int, u_int, struct bpf_if **);
+        void (*bpf_detach)(struct ifnet *);
+        void (*bpf_change_type)(struct ifnet *, u_int, u_int);
+
+        void (*bpf_tap)(struct bpf_if *, u_char *, u_int);
+        void (*bpf_mtap)(struct bpf_if *, struct mbuf *);
+        void (*bpf_mtap2)(struct bpf_if *, void *, u_int, struct mbuf *);
+        void (*bpf_mtap_af)(struct bpf_if *, uint32_t, struct mbuf *);
+        void (*bpf_mtap_et)(struct bpf_if *, uint16_t, struct mbuf *);
+        void (*bpf_mtap_sl_in)(struct bpf_if *, u_char *, struct mbuf **);
+        void (*bpf_mtap_sl_out)(struct bpf_if *, u_char *, struct mbuf *);
+};
+.Ed
+.Pp
+This vector is found from
+.Vt struct bpf_ops *
+.Va bpf_ops ,
+and is either a stub implementation or a real implementation depending
+on if bpf is absent or present in the kernel, respectively.
+.Sh CODE REFERENCES
+This section describes places within the
+.Nx
+source tree where the implementation can be found.
+All pathnames are relative to
+.Pa /usr/src .
+.Pp
+The
+.Nm
+implementation is located in
+.Pa sys/net/bpf.c ,
+the stub implementation is in
+.Pa sys/net/bpf_stub.c
+and the interface is defined in
+.Pa sys/net/bpf.h .