507 lines
13 KiB
C
507 lines
13 KiB
C
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/*
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* ng_bpf.c
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*
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* Copyright (c) 1999 Whistle Communications, Inc.
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* All rights reserved.
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*
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* Subject to the following obligations and disclaimer of warranty, use and
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* redistribution of this software, in source or object code forms, with or
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* without modifications are expressly permitted by Whistle Communications;
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* provided, however, that:
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* 1. Any and all reproductions of the source or object code must include the
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* copyright notice above and the following disclaimer of warranties; and
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* 2. No rights are granted, in any manner or form, to use Whistle
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* Communications, Inc. trademarks, including the mark "WHISTLE
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* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
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* such appears in the above copyright notice or in the software.
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*
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* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
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* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
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* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
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* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
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* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
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* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
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* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
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* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
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* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
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* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* Author: Archie Cobbs <archie@freebsd.org>
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*
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* $FreeBSD$
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* $Whistle: ng_bpf.c,v 1.3 1999/12/03 20:30:23 archie Exp $
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*/
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/*
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* BPF NETGRAPH NODE TYPE
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*
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* This node type accepts any number of hook connections. With each hook
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* is associated a bpf(4) filter program, and two hook names (each possibly
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* the empty string). Incoming packets are compared against the filter;
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* matching packets are delivered out the first named hook (or dropped if
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* the empty string), and non-matching packets are delivered out the second
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* named hook (or dropped if the empty string).
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*
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* Each hook also keeps statistics about how many packets have matched, etc.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/errno.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <net/bpf.h>
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#include <netgraph/ng_message.h>
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#include <netgraph/netgraph.h>
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#include <netgraph/ng_parse.h>
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#include <netgraph/ng_bpf.h>
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#ifdef NG_SEPARATE_MALLOC
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MALLOC_DEFINE(M_NETGRAPH_BPF, "netgraph_bpf", "netgraph bpf node ");
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#else
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#define M_NETGRAPH_BPF M_NETGRAPH
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#endif
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#define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0))
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#define ERROUT(x) do { error = (x); goto done; } while (0)
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/* Per hook private info */
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struct ng_bpf_hookinfo {
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node_p node;
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hook_p hook;
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struct ng_bpf_hookprog *prog;
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struct ng_bpf_hookstat stats;
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};
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typedef struct ng_bpf_hookinfo *hinfo_p;
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/* Netgraph methods */
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static ng_constructor_t ng_bpf_constructor;
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static ng_rcvmsg_t ng_bpf_rcvmsg;
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static ng_shutdown_t ng_bpf_shutdown;
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static ng_newhook_t ng_bpf_newhook;
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static ng_rcvdata_t ng_bpf_rcvdata;
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static ng_disconnect_t ng_bpf_disconnect;
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/* Internal helper functions */
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static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp);
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/* Parse type for one struct bfp_insn */
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static const struct ng_parse_struct_info ng_bpf_insn_type_info = {
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{
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{ "code", &ng_parse_hint16_type },
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{ "jt", &ng_parse_uint8_type },
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{ "jf", &ng_parse_uint8_type },
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{ "k", &ng_parse_uint32_type },
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{ NULL }
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}
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};
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static const struct ng_parse_type ng_bpf_insn_type = {
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&ng_parse_struct_type,
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&ng_bpf_insn_type_info
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};
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/* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */
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static int
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ng_bpf_hookprogary_getLength(const struct ng_parse_type *type,
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const u_char *start, const u_char *buf)
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{
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const struct ng_bpf_hookprog *hp;
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hp = (const struct ng_bpf_hookprog *)
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(buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog));
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return hp->bpf_prog_len;
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}
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static const struct ng_parse_array_info ng_bpf_hookprogary_info = {
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&ng_bpf_insn_type,
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&ng_bpf_hookprogary_getLength,
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NULL
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};
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static const struct ng_parse_type ng_bpf_hookprogary_type = {
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&ng_parse_array_type,
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&ng_bpf_hookprogary_info
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};
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/* Parse type for struct ng_bpf_hookprog */
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static const struct ng_parse_struct_info ng_bpf_hookprog_type_info
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= NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type);
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static const struct ng_parse_type ng_bpf_hookprog_type = {
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&ng_parse_struct_type,
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&ng_bpf_hookprog_type_info
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};
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/* Parse type for struct ng_bpf_hookstat */
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static const struct ng_parse_struct_info
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ng_bpf_hookstat_type_info = NG_BPF_HOOKSTAT_TYPE_INFO;
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static const struct ng_parse_type ng_bpf_hookstat_type = {
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&ng_parse_struct_type,
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&ng_bpf_hookstat_type_info
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};
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/* List of commands and how to convert arguments to/from ASCII */
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static const struct ng_cmdlist ng_bpf_cmdlist[] = {
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{
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NGM_BPF_COOKIE,
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NGM_BPF_SET_PROGRAM,
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"setprogram",
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&ng_bpf_hookprog_type,
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NULL
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},
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{
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NGM_BPF_COOKIE,
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NGM_BPF_GET_PROGRAM,
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"getprogram",
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&ng_parse_hookbuf_type,
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&ng_bpf_hookprog_type
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},
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{
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NGM_BPF_COOKIE,
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NGM_BPF_GET_STATS,
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"getstats",
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&ng_parse_hookbuf_type,
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&ng_bpf_hookstat_type
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},
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{
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NGM_BPF_COOKIE,
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NGM_BPF_CLR_STATS,
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"clrstats",
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&ng_parse_hookbuf_type,
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NULL
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},
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{
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NGM_BPF_COOKIE,
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NGM_BPF_GETCLR_STATS,
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"getclrstats",
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&ng_parse_hookbuf_type,
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&ng_bpf_hookstat_type
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},
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{ 0 }
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};
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/* Netgraph type descriptor */
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static struct ng_type typestruct = {
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NG_ABI_VERSION,
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NG_BPF_NODE_TYPE,
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NULL,
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ng_bpf_constructor,
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ng_bpf_rcvmsg,
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ng_bpf_shutdown,
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ng_bpf_newhook,
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NULL,
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NULL,
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ng_bpf_rcvdata,
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ng_bpf_disconnect,
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ng_bpf_cmdlist
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};
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NETGRAPH_INIT(bpf, &typestruct);
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/* Default BPF program for a hook that matches nothing */
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static const struct ng_bpf_hookprog ng_bpf_default_prog = {
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{ '\0' }, /* to be filled in at hook creation time */
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{ '\0' },
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{ '\0' },
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1,
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{ BPF_STMT(BPF_RET+BPF_K, 0) }
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};
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/*
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* Node constructor
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*
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* We don't keep any per-node private data
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* We go via the hooks.
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*/
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static int
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ng_bpf_constructor(node_p node)
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{
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NG_NODE_SET_PRIVATE(node, NULL);
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return (0);
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}
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/*
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* Add a hook
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*/
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static int
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ng_bpf_newhook(node_p node, hook_p hook, const char *name)
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{
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hinfo_p hip;
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int error;
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/* Create hook private structure */
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MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH_BPF, M_NOWAIT | M_ZERO);
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if (hip == NULL)
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return (ENOMEM);
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hip->hook = hook;
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NG_HOOK_SET_PRIVATE(hook, hip);
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hip->node = node;
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/* Attach the default BPF program */
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if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) {
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FREE(hip, M_NETGRAPH_BPF);
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NG_HOOK_SET_PRIVATE(hook, NULL);
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return (error);
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}
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/* Set hook name */
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strncpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook) - 1);
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hip->prog->thisHook[sizeof(hip->prog->thisHook) - 1] = '\0';
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return (0);
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}
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/*
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* Receive a control message
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*/
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static int
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ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook)
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{
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struct ng_mesg *msg;
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struct ng_mesg *resp = NULL;
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int error = 0;
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NGI_GET_MSG(item, msg);
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switch (msg->header.typecookie) {
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case NGM_BPF_COOKIE:
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switch (msg->header.cmd) {
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case NGM_BPF_SET_PROGRAM:
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{
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struct ng_bpf_hookprog *const
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hp = (struct ng_bpf_hookprog *)msg->data;
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hook_p hook;
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/* Sanity check */
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if (msg->header.arglen < sizeof(*hp)
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|| msg->header.arglen
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!= NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len))
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ERROUT(EINVAL);
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/* Find hook */
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if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
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ERROUT(ENOENT);
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/* Set new program */
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if ((error = ng_bpf_setprog(hook, hp)) != 0)
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ERROUT(error);
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break;
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}
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case NGM_BPF_GET_PROGRAM:
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{
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struct ng_bpf_hookprog *hp;
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hook_p hook;
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/* Sanity check */
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if (msg->header.arglen == 0)
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ERROUT(EINVAL);
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msg->data[msg->header.arglen - 1] = '\0';
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/* Find hook */
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if ((hook = ng_findhook(node, msg->data)) == NULL)
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ERROUT(ENOENT);
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/* Build response */
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hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->prog;
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NG_MKRESPONSE(resp, msg,
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NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT);
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if (resp == NULL)
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ERROUT(ENOMEM);
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bcopy(hp, resp->data,
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NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len));
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break;
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}
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case NGM_BPF_GET_STATS:
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case NGM_BPF_CLR_STATS:
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case NGM_BPF_GETCLR_STATS:
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{
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struct ng_bpf_hookstat *stats;
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hook_p hook;
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/* Sanity check */
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if (msg->header.arglen == 0)
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ERROUT(EINVAL);
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msg->data[msg->header.arglen - 1] = '\0';
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/* Find hook */
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if ((hook = ng_findhook(node, msg->data)) == NULL)
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ERROUT(ENOENT);
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stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
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/* Build response (if desired) */
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if (msg->header.cmd != NGM_BPF_CLR_STATS) {
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NG_MKRESPONSE(resp,
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msg, sizeof(*stats), M_NOWAIT);
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if (resp == NULL)
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ERROUT(ENOMEM);
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bcopy(stats, resp->data, sizeof(*stats));
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}
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/* Clear stats (if desired) */
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if (msg->header.cmd != NGM_BPF_GET_STATS)
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bzero(stats, sizeof(*stats));
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break;
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}
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default:
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error = EINVAL;
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break;
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}
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break;
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default:
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error = EINVAL;
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break;
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}
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done:
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NG_RESPOND_MSG(error, node, item, resp);
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NG_FREE_MSG(msg);
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return (error);
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}
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/*
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* Receive data on a hook
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*
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* Apply the filter, and then drop or forward packet as appropriate.
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*/
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static int
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ng_bpf_rcvdata(hook_p hook, item_p item)
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{
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const hinfo_p hip = NG_HOOK_PRIVATE(hook);
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int totlen;
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int needfree = 0, error = 0;
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u_char *data, buf[256];
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hinfo_p dhip;
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hook_p dest;
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u_int len;
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struct mbuf *m;
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m = NGI_M(item); /* 'item' still owns it.. we are peeking */
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totlen = m->m_pkthdr.len;
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/* Update stats on incoming hook. XXX Can we do 64 bits atomically? */
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/* atomic_add_int64(&hip->stats.recvFrames, 1); */
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/* atomic_add_int64(&hip->stats.recvOctets, totlen); */
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hip->stats.recvFrames++;
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hip->stats.recvOctets += totlen;
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/* Need to put packet in contiguous memory for bpf */
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if (m->m_next != NULL) {
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if (totlen > sizeof(buf)) {
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MALLOC(data, u_char *, totlen, M_NETGRAPH_BPF, M_NOWAIT);
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if (data == NULL) {
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NG_FREE_ITEM(item);
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return (ENOMEM);
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}
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needfree = 1;
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} else
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data = buf;
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m_copydata(m, 0, totlen, (caddr_t)data);
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} else
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data = mtod(m, u_char *);
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/* Run packet through filter */
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len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen);
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if (needfree)
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FREE(data, M_NETGRAPH_BPF);
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/* See if we got a match and find destination hook */
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if (len > 0) {
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/* Update stats */
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/* XXX atomically? */
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hip->stats.recvMatchFrames++;
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hip->stats.recvMatchOctets += totlen;
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/* Truncate packet length if required by the filter */
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/* Assume this never changes m */
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if (len < totlen) {
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m_adj(m, -(totlen - len));
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totlen -= len;
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}
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dest = ng_findhook(hip->node, hip->prog->ifMatch);
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} else
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dest = ng_findhook(hip->node, hip->prog->ifNotMatch);
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if (dest == NULL) {
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NG_FREE_ITEM(item);
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return (0);
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}
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/* Deliver frame out destination hook */
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dhip = NG_HOOK_PRIVATE(dest);
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dhip->stats.xmitOctets += totlen;
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dhip->stats.xmitFrames++;
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NG_FWD_ITEM_HOOK(error, item, dest);
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return (error);
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}
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/*
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* Shutdown processing
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*/
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static int
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ng_bpf_shutdown(node_p node)
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{
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NG_NODE_UNREF(node);
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return (0);
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}
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/*
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* Hook disconnection
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*/
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static int
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ng_bpf_disconnect(hook_p hook)
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{
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const hinfo_p hip = NG_HOOK_PRIVATE(hook);
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KASSERT(hip != NULL, ("%s: null info", __FUNCTION__));
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FREE(hip->prog, M_NETGRAPH_BPF);
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bzero(hip, sizeof(*hip));
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FREE(hip, M_NETGRAPH_BPF);
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NG_HOOK_SET_PRIVATE(hook, NULL); /* for good measure */
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if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
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&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
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ng_rmnode_self(NG_HOOK_NODE(hook));
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}
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return (0);
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}
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/************************************************************************
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HELPER STUFF
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************************************************************************/
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/*
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* Set the BPF program associated with a hook
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*/
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static int
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ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0)
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{
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const hinfo_p hip = NG_HOOK_PRIVATE(hook);
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struct ng_bpf_hookprog *hp;
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int size;
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/* Check program for validity */
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if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len))
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return (EINVAL);
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/* Make a copy of the program */
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size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len);
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MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH_BPF, M_NOWAIT);
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if (hp == NULL)
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return (ENOMEM);
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bcopy(hp0, hp, size);
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/* Free previous program, if any, and assign new one */
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if (hip->prog != NULL)
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FREE(hip->prog, M_NETGRAPH_BPF);
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hip->prog = hp;
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return (0);
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}
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