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