xref: /freebsd/sys/netgraph/ng_ether.c (revision 9162f64b58d01ec01481d60b6cdc06ffd8e8c7fc)
1 
2 /*
3  * ng_ether.c
4  */
5 
6 /*-
7  * Copyright (c) 1996-2000 Whistle Communications, Inc.
8  * All rights reserved.
9  *
10  * Subject to the following obligations and disclaimer of warranty, use and
11  * redistribution of this software, in source or object code forms, with or
12  * without modifications are expressly permitted by Whistle Communications;
13  * provided, however, that:
14  * 1. Any and all reproductions of the source or object code must include the
15  *    copyright notice above and the following disclaimer of warranties; and
16  * 2. No rights are granted, in any manner or form, to use Whistle
17  *    Communications, Inc. trademarks, including the mark "WHISTLE
18  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
19  *    such appears in the above copyright notice or in the software.
20  *
21  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
22  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
23  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
24  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
26  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
27  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
28  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
29  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
30  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
31  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
32  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
33  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
34  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
37  * OF SUCH DAMAGE.
38  *
39  * Authors: Archie Cobbs <archie@freebsd.org>
40  *	    Julian Elischer <julian@freebsd.org>
41  *
42  * $FreeBSD$
43  */
44 
45 /*
46  * ng_ether(4) netgraph node type
47  */
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/kernel.h>
52 #include <sys/malloc.h>
53 #include <sys/mbuf.h>
54 #include <sys/errno.h>
55 #include <sys/syslog.h>
56 #include <sys/socket.h>
57 #include <sys/vimage.h>
58 
59 #include <net/if.h>
60 #include <net/if_dl.h>
61 #include <net/if_types.h>
62 #include <net/if_arp.h>
63 #include <net/if_var.h>
64 #include <net/ethernet.h>
65 #include <net/if_bridgevar.h>
66 #include <net/vnet.h>
67 
68 #include <netgraph/ng_message.h>
69 #include <netgraph/netgraph.h>
70 #include <netgraph/ng_parse.h>
71 #include <netgraph/ng_ether.h>
72 
73 #define IFP2NG(ifp)  (IFP2AC((ifp))->ac_netgraph)
74 
75 /* Per-node private data */
76 struct private {
77 	struct ifnet	*ifp;		/* associated interface */
78 	hook_p		upper;		/* upper hook connection */
79 	hook_p		lower;		/* lower hook connection */
80 	hook_p		orphan;		/* orphan hook connection */
81 	u_char		autoSrcAddr;	/* always overwrite source address */
82 	u_char		promisc;	/* promiscuous mode enabled */
83 	u_long		hwassist;	/* hardware checksum capabilities */
84 	u_int		flags;		/* flags e.g. really die */
85 };
86 typedef struct private *priv_p;
87 
88 /* Hook pointers used by if_ethersubr.c to callback to netgraph */
89 extern	void	(*ng_ether_input_p)(struct ifnet *ifp, struct mbuf **mp);
90 extern	void	(*ng_ether_input_orphan_p)(struct ifnet *ifp, struct mbuf *m);
91 extern	int	(*ng_ether_output_p)(struct ifnet *ifp, struct mbuf **mp);
92 extern	void	(*ng_ether_attach_p)(struct ifnet *ifp);
93 extern	void	(*ng_ether_detach_p)(struct ifnet *ifp);
94 extern	void	(*ng_ether_link_state_p)(struct ifnet *ifp, int state);
95 
96 /* Functional hooks called from if_ethersubr.c */
97 static void	ng_ether_input(struct ifnet *ifp, struct mbuf **mp);
98 static void	ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m);
99 static int	ng_ether_output(struct ifnet *ifp, struct mbuf **mp);
100 static void	ng_ether_attach(struct ifnet *ifp);
101 static void	ng_ether_detach(struct ifnet *ifp);
102 static void	ng_ether_link_state(struct ifnet *ifp, int state);
103 
104 /* Other functions */
105 static int	ng_ether_rcv_lower(hook_p node, item_p item);
106 static int	ng_ether_rcv_upper(hook_p node, item_p item);
107 
108 /* Netgraph node methods */
109 static ng_constructor_t	ng_ether_constructor;
110 static ng_rcvmsg_t	ng_ether_rcvmsg;
111 static ng_shutdown_t	ng_ether_shutdown;
112 static ng_newhook_t	ng_ether_newhook;
113 static ng_rcvdata_t	ng_ether_rcvdata;
114 static ng_disconnect_t	ng_ether_disconnect;
115 static int		ng_ether_mod_event(module_t mod, int event, void *data);
116 
117 /* List of commands and how to convert arguments to/from ASCII */
118 static const struct ng_cmdlist ng_ether_cmdlist[] = {
119 	{
120 	  NGM_ETHER_COOKIE,
121 	  NGM_ETHER_GET_IFNAME,
122 	  "getifname",
123 	  NULL,
124 	  &ng_parse_string_type
125 	},
126 	{
127 	  NGM_ETHER_COOKIE,
128 	  NGM_ETHER_GET_IFINDEX,
129 	  "getifindex",
130 	  NULL,
131 	  &ng_parse_int32_type
132 	},
133 	{
134 	  NGM_ETHER_COOKIE,
135 	  NGM_ETHER_GET_ENADDR,
136 	  "getenaddr",
137 	  NULL,
138 	  &ng_parse_enaddr_type
139 	},
140 	{
141 	  NGM_ETHER_COOKIE,
142 	  NGM_ETHER_SET_ENADDR,
143 	  "setenaddr",
144 	  &ng_parse_enaddr_type,
145 	  NULL
146 	},
147 	{
148 	  NGM_ETHER_COOKIE,
149 	  NGM_ETHER_GET_PROMISC,
150 	  "getpromisc",
151 	  NULL,
152 	  &ng_parse_int32_type
153 	},
154 	{
155 	  NGM_ETHER_COOKIE,
156 	  NGM_ETHER_SET_PROMISC,
157 	  "setpromisc",
158 	  &ng_parse_int32_type,
159 	  NULL
160 	},
161 	{
162 	  NGM_ETHER_COOKIE,
163 	  NGM_ETHER_GET_AUTOSRC,
164 	  "getautosrc",
165 	  NULL,
166 	  &ng_parse_int32_type
167 	},
168 	{
169 	  NGM_ETHER_COOKIE,
170 	  NGM_ETHER_SET_AUTOSRC,
171 	  "setautosrc",
172 	  &ng_parse_int32_type,
173 	  NULL
174 	},
175 	{
176 	  NGM_ETHER_COOKIE,
177 	  NGM_ETHER_ADD_MULTI,
178 	  "addmulti",
179 	  &ng_parse_enaddr_type,
180 	  NULL
181 	},
182 	{
183 	  NGM_ETHER_COOKIE,
184 	  NGM_ETHER_DEL_MULTI,
185 	  "delmulti",
186 	  &ng_parse_enaddr_type,
187 	  NULL
188 	},
189 	{
190 	  NGM_ETHER_COOKIE,
191 	  NGM_ETHER_DETACH,
192 	  "detach",
193 	  NULL,
194 	  NULL
195 	},
196 	{ 0 }
197 };
198 
199 static struct ng_type ng_ether_typestruct = {
200 	.version =	NG_ABI_VERSION,
201 	.name =		NG_ETHER_NODE_TYPE,
202 	.mod_event =	ng_ether_mod_event,
203 	.constructor =	ng_ether_constructor,
204 	.rcvmsg =	ng_ether_rcvmsg,
205 	.shutdown =	ng_ether_shutdown,
206 	.newhook =	ng_ether_newhook,
207 	.rcvdata =	ng_ether_rcvdata,
208 	.disconnect =	ng_ether_disconnect,
209 	.cmdlist =	ng_ether_cmdlist,
210 };
211 NETGRAPH_INIT(ether, &ng_ether_typestruct);
212 
213 /******************************************************************
214 		    ETHERNET FUNCTION HOOKS
215 ******************************************************************/
216 
217 /*
218  * Handle a packet that has come in on an interface. We get to
219  * look at it here before any upper layer protocols do.
220  *
221  * NOTE: this function will get called at splimp()
222  */
223 static void
224 ng_ether_input(struct ifnet *ifp, struct mbuf **mp)
225 {
226 	const node_p node = IFP2NG(ifp);
227 	const priv_p priv = NG_NODE_PRIVATE(node);
228 	int error;
229 
230 	/* If "lower" hook not connected, let packet continue */
231 	if (priv->lower == NULL)
232 		return;
233 	NG_SEND_DATA_ONLY(error, priv->lower, *mp);	/* sets *mp = NULL */
234 }
235 
236 /*
237  * Handle a packet that has come in on an interface, and which
238  * does not match any of our known protocols (an ``orphan'').
239  *
240  * NOTE: this function will get called at splimp()
241  */
242 static void
243 ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m)
244 {
245 	const node_p node = IFP2NG(ifp);
246 	const priv_p priv = NG_NODE_PRIVATE(node);
247 	int error;
248 
249 	/* If "orphan" hook not connected, discard packet */
250 	if (priv->orphan == NULL) {
251 		m_freem(m);
252 		return;
253 	}
254 	NG_SEND_DATA_ONLY(error, priv->orphan, m);
255 }
256 
257 /*
258  * Handle a packet that is going out on an interface.
259  * The Ethernet header is already attached to the mbuf.
260  */
261 static int
262 ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
263 {
264 	const node_p node = IFP2NG(ifp);
265 	const priv_p priv = NG_NODE_PRIVATE(node);
266 	int error = 0;
267 
268 	/* If "upper" hook not connected, let packet continue */
269 	if (priv->upper == NULL)
270 		return (0);
271 
272 	/* Send it out "upper" hook */
273 	NG_SEND_DATA_ONLY(error, priv->upper, *mp);
274 	return (error);
275 }
276 
277 /*
278  * A new Ethernet interface has been attached.
279  * Create a new node for it, etc.
280  */
281 static void
282 ng_ether_attach(struct ifnet *ifp)
283 {
284 	priv_p priv;
285 	node_p node;
286 
287 	/* Create node */
288 	KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __func__));
289 	if (ng_make_node_common(&ng_ether_typestruct, &node) != 0) {
290 		log(LOG_ERR, "%s: can't %s for %s\n",
291 		    __func__, "create node", ifp->if_xname);
292 		return;
293 	}
294 
295 	/* Allocate private data */
296 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
297 	if (priv == NULL) {
298 		log(LOG_ERR, "%s: can't %s for %s\n",
299 		    __func__, "allocate memory", ifp->if_xname);
300 		NG_NODE_UNREF(node);
301 		return;
302 	}
303 	NG_NODE_SET_PRIVATE(node, priv);
304 	priv->ifp = ifp;
305 	IFP2NG(ifp) = node;
306 	priv->hwassist = ifp->if_hwassist;
307 
308 	/* Try to give the node the same name as the interface */
309 	if (ng_name_node(node, ifp->if_xname) != 0) {
310 		log(LOG_WARNING, "%s: can't name node %s\n",
311 		    __func__, ifp->if_xname);
312 	}
313 }
314 
315 /*
316  * An Ethernet interface is being detached.
317  * REALLY Destroy its node.
318  */
319 static void
320 ng_ether_detach(struct ifnet *ifp)
321 {
322 	const node_p node = IFP2NG(ifp);
323 	const priv_p priv = NG_NODE_PRIVATE(node);
324 
325 	NG_NODE_REALLY_DIE(node);	/* Force real removal of node */
326 	/*
327 	 * We can't assume the ifnet is still around when we run shutdown
328 	 * So zap it now. XXX We HOPE that anything running at this time
329 	 * handles it (as it should in the non netgraph case).
330 	 */
331 	IFP2NG(ifp) = NULL;
332 	priv->ifp = NULL;	/* XXX race if interrupted an output packet */
333 	ng_rmnode_self(node);		/* remove all netgraph parts */
334 }
335 
336 /*
337  * Notify graph about link event.
338  * if_link_state_change() has already checked that the state has changed.
339  */
340 static void
341 ng_ether_link_state(struct ifnet *ifp, int state)
342 {
343 	const node_p node = IFP2NG(ifp);
344 	const priv_p priv = NG_NODE_PRIVATE(node);
345 	struct ng_mesg *msg;
346 	int cmd, dummy_error = 0;
347 
348 	if (priv->lower == NULL)
349                 return;
350 
351 	if (state == LINK_STATE_UP)
352 		cmd = NGM_LINK_IS_UP;
353 	else if (state == LINK_STATE_DOWN)
354 		cmd = NGM_LINK_IS_DOWN;
355 	else
356 		return;
357 
358 	NG_MKMESSAGE(msg, NGM_FLOW_COOKIE, cmd, 0, M_NOWAIT);
359 	if (msg != NULL)
360 		NG_SEND_MSG_HOOK(dummy_error, node, msg, priv->lower, 0);
361 }
362 
363 /******************************************************************
364 		    NETGRAPH NODE METHODS
365 ******************************************************************/
366 
367 /*
368  * It is not possible or allowable to create a node of this type.
369  * Nodes get created when the interface is attached (or, when
370  * this node type's KLD is loaded).
371  */
372 static int
373 ng_ether_constructor(node_p node)
374 {
375 	return (EINVAL);
376 }
377 
378 /*
379  * Check for attaching a new hook.
380  */
381 static	int
382 ng_ether_newhook(node_p node, hook_p hook, const char *name)
383 {
384 	const priv_p priv = NG_NODE_PRIVATE(node);
385 	hook_p *hookptr;
386 
387 	/* Divert hook is an alias for lower */
388 	if (strcmp(name, NG_ETHER_HOOK_DIVERT) == 0)
389 		name = NG_ETHER_HOOK_LOWER;
390 
391 	/* Which hook? */
392 	if (strcmp(name, NG_ETHER_HOOK_UPPER) == 0) {
393 		hookptr = &priv->upper;
394 		NG_HOOK_SET_RCVDATA(hook, ng_ether_rcv_upper);
395 	} else if (strcmp(name, NG_ETHER_HOOK_LOWER) == 0) {
396 		hookptr = &priv->lower;
397 		NG_HOOK_SET_RCVDATA(hook, ng_ether_rcv_lower);
398 	} else if (strcmp(name, NG_ETHER_HOOK_ORPHAN) == 0) {
399 		hookptr = &priv->orphan;
400 		NG_HOOK_SET_RCVDATA(hook, ng_ether_rcv_lower);
401 	} else
402 		return (EINVAL);
403 
404 	/* Check if already connected (shouldn't be, but doesn't hurt) */
405 	if (*hookptr != NULL)
406 		return (EISCONN);
407 
408 	/* Disable hardware checksums while 'upper' hook is connected */
409 	if (hookptr == &priv->upper)
410 		priv->ifp->if_hwassist = 0;
411 
412 	/* OK */
413 	*hookptr = hook;
414 	return (0);
415 }
416 
417 /*
418  * Receive an incoming control message.
419  */
420 static int
421 ng_ether_rcvmsg(node_p node, item_p item, hook_p lasthook)
422 {
423 	const priv_p priv = NG_NODE_PRIVATE(node);
424 	struct ng_mesg *resp = NULL;
425 	int error = 0;
426 	struct ng_mesg *msg;
427 
428 	NGI_GET_MSG(item, msg);
429 	switch (msg->header.typecookie) {
430 	case NGM_ETHER_COOKIE:
431 		switch (msg->header.cmd) {
432 		case NGM_ETHER_GET_IFNAME:
433 			NG_MKRESPONSE(resp, msg, IFNAMSIZ, M_NOWAIT);
434 			if (resp == NULL) {
435 				error = ENOMEM;
436 				break;
437 			}
438 			strlcpy(resp->data, priv->ifp->if_xname, IFNAMSIZ);
439 			break;
440 		case NGM_ETHER_GET_IFINDEX:
441 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
442 			if (resp == NULL) {
443 				error = ENOMEM;
444 				break;
445 			}
446 			*((u_int32_t *)resp->data) = priv->ifp->if_index;
447 			break;
448 		case NGM_ETHER_GET_ENADDR:
449 			NG_MKRESPONSE(resp, msg, ETHER_ADDR_LEN, M_NOWAIT);
450 			if (resp == NULL) {
451 				error = ENOMEM;
452 				break;
453 			}
454 			bcopy(IF_LLADDR(priv->ifp),
455 			    resp->data, ETHER_ADDR_LEN);
456 			break;
457 		case NGM_ETHER_SET_ENADDR:
458 		    {
459 			if (msg->header.arglen != ETHER_ADDR_LEN) {
460 				error = EINVAL;
461 				break;
462 			}
463 			error = if_setlladdr(priv->ifp,
464 			    (u_char *)msg->data, ETHER_ADDR_LEN);
465 			break;
466 		    }
467 		case NGM_ETHER_GET_PROMISC:
468 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
469 			if (resp == NULL) {
470 				error = ENOMEM;
471 				break;
472 			}
473 			*((u_int32_t *)resp->data) = priv->promisc;
474 			break;
475 		case NGM_ETHER_SET_PROMISC:
476 		    {
477 			u_char want;
478 
479 			if (msg->header.arglen != sizeof(u_int32_t)) {
480 				error = EINVAL;
481 				break;
482 			}
483 			want = !!*((u_int32_t *)msg->data);
484 			if (want ^ priv->promisc) {
485 				if ((error = ifpromisc(priv->ifp, want)) != 0)
486 					break;
487 				priv->promisc = want;
488 			}
489 			break;
490 		    }
491 		case NGM_ETHER_GET_AUTOSRC:
492 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
493 			if (resp == NULL) {
494 				error = ENOMEM;
495 				break;
496 			}
497 			*((u_int32_t *)resp->data) = priv->autoSrcAddr;
498 			break;
499 		case NGM_ETHER_SET_AUTOSRC:
500 			if (msg->header.arglen != sizeof(u_int32_t)) {
501 				error = EINVAL;
502 				break;
503 			}
504 			priv->autoSrcAddr = !!*((u_int32_t *)msg->data);
505 			break;
506 		case NGM_ETHER_ADD_MULTI:
507 		    {
508 			struct sockaddr_dl sa_dl;
509 			struct ifmultiaddr *ifma;
510 
511 			if (msg->header.arglen != ETHER_ADDR_LEN) {
512 				error = EINVAL;
513 				break;
514 			}
515 			bzero(&sa_dl, sizeof(struct sockaddr_dl));
516 			sa_dl.sdl_len = sizeof(struct sockaddr_dl);
517 			sa_dl.sdl_family = AF_LINK;
518 			sa_dl.sdl_alen = ETHER_ADDR_LEN;
519 			bcopy((void *)msg->data, LLADDR(&sa_dl),
520 			    ETHER_ADDR_LEN);
521 			/*
522 			 * Netgraph is only permitted to join groups once
523 			 * via the if_addmulti() KPI, because it cannot hold
524 			 * struct ifmultiaddr * between calls. It may also
525 			 * lose a race while we check if the membership
526 			 * already exists.
527 			 */
528 			IF_ADDR_LOCK(priv->ifp);
529 			ifma = if_findmulti(priv->ifp,
530 			    (struct sockaddr *)&sa_dl);
531 			IF_ADDR_UNLOCK(priv->ifp);
532 			if (ifma != NULL) {
533 				error = EADDRINUSE;
534 			} else {
535 				error = if_addmulti(priv->ifp,
536 				    (struct sockaddr *)&sa_dl, &ifma);
537 			}
538 			break;
539 		    }
540 		case NGM_ETHER_DEL_MULTI:
541 		    {
542 			struct sockaddr_dl sa_dl;
543 
544 			if (msg->header.arglen != ETHER_ADDR_LEN) {
545 				error = EINVAL;
546 				break;
547 			}
548 			bzero(&sa_dl, sizeof(struct sockaddr_dl));
549 			sa_dl.sdl_len = sizeof(struct sockaddr_dl);
550 			sa_dl.sdl_family = AF_LINK;
551 			sa_dl.sdl_alen = ETHER_ADDR_LEN;
552 			bcopy((void *)msg->data, LLADDR(&sa_dl),
553 			    ETHER_ADDR_LEN);
554 			error = if_delmulti(priv->ifp,
555 			    (struct sockaddr *)&sa_dl);
556 			break;
557 		    }
558 		case NGM_ETHER_DETACH:
559 			ng_ether_detach(priv->ifp);
560 			break;
561 		default:
562 			error = EINVAL;
563 			break;
564 		}
565 		break;
566 	default:
567 		error = EINVAL;
568 		break;
569 	}
570 	NG_RESPOND_MSG(error, node, item, resp);
571 	NG_FREE_MSG(msg);
572 	return (error);
573 }
574 
575 /*
576  * Receive data on a hook.
577  * Since we use per-hook recveive methods this should never be called.
578  */
579 static int
580 ng_ether_rcvdata(hook_p hook, item_p item)
581 {
582 	NG_FREE_ITEM(item);
583 
584 	panic("%s: weird hook", __func__);
585 #ifdef RESTARTABLE_PANICS /* so we don't get an error msg in LINT */
586 	return (0);
587 #endif
588 }
589 
590 /*
591  * Handle an mbuf received on the "lower" or "orphan" hook.
592  */
593 static int
594 ng_ether_rcv_lower(hook_p hook, item_p item)
595 {
596 	struct mbuf *m;
597 	const node_p node = NG_HOOK_NODE(hook);
598 	const priv_p priv = NG_NODE_PRIVATE(node);
599  	struct ifnet *const ifp = priv->ifp;
600 
601 	NGI_GET_M(item, m);
602 	NG_FREE_ITEM(item);
603 
604 	/* Check whether interface is ready for packets */
605 
606 	if (!((ifp->if_flags & IFF_UP) &&
607 	    (ifp->if_drv_flags & IFF_DRV_RUNNING))) {
608 		NG_FREE_M(m);
609 		return (ENETDOWN);
610 	}
611 
612 	/* Make sure header is fully pulled up */
613 	if (m->m_pkthdr.len < sizeof(struct ether_header)) {
614 		NG_FREE_M(m);
615 		return (EINVAL);
616 	}
617 	if (m->m_len < sizeof(struct ether_header)
618 	    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
619 		return (ENOBUFS);
620 
621 	/* Drop in the MAC address if desired */
622 	if (priv->autoSrcAddr) {
623 
624 		/* Make the mbuf writable if it's not already */
625 		if (!M_WRITABLE(m)
626 		    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
627 			return (ENOBUFS);
628 
629 		/* Overwrite source MAC address */
630 		bcopy(IF_LLADDR(ifp),
631 		    mtod(m, struct ether_header *)->ether_shost,
632 		    ETHER_ADDR_LEN);
633 	}
634 
635 	/* Send it on its way */
636 	return ether_output_frame(ifp, m);
637 }
638 
639 /*
640  * Handle an mbuf received on the "upper" hook.
641  */
642 static int
643 ng_ether_rcv_upper(hook_p hook, item_p item)
644 {
645 	struct mbuf *m;
646 	const node_p node = NG_HOOK_NODE(hook);
647 	const priv_p priv = NG_NODE_PRIVATE(node);
648 	struct ifnet *ifp = priv->ifp;
649 
650 	NGI_GET_M(item, m);
651 	NG_FREE_ITEM(item);
652 
653 	/* Check length and pull off header */
654 	if (m->m_pkthdr.len < sizeof(struct ether_header)) {
655 		NG_FREE_M(m);
656 		return (EINVAL);
657 	}
658 	if (m->m_len < sizeof(struct ether_header) &&
659 	    (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
660 		return (ENOBUFS);
661 
662 	m->m_pkthdr.rcvif = ifp;
663 
664 	/* Pass the packet to the bridge, it may come back to us */
665 	if (ifp->if_bridge) {
666 		BRIDGE_INPUT(ifp, m);
667 		if (m == NULL)
668 			return (0);
669 	}
670 
671 	/* Route packet back in */
672 	ether_demux(ifp, m);
673 	return (0);
674 }
675 
676 /*
677  * Shutdown node. This resets the node but does not remove it
678  * unless the REALLY_DIE flag is set.
679  */
680 static int
681 ng_ether_shutdown(node_p node)
682 {
683 	const priv_p priv = NG_NODE_PRIVATE(node);
684 
685 	if (node->nd_flags & NGF_REALLY_DIE) {
686 		/*
687 		 * WE came here because the ethernet card is being unloaded,
688 		 * so stop being persistant.
689 		 * Actually undo all the things we did on creation.
690 		 * Assume the ifp has already been freed.
691 		 */
692 		NG_NODE_SET_PRIVATE(node, NULL);
693 		free(priv, M_NETGRAPH);
694 		NG_NODE_UNREF(node);	/* free node itself */
695 		return (0);
696 	}
697 	if (priv->promisc) {		/* disable promiscuous mode */
698 		(void)ifpromisc(priv->ifp, 0);
699 		priv->promisc = 0;
700 	}
701 	priv->autoSrcAddr = 1;		/* reset auto-src-addr flag */
702 	NG_NODE_REVIVE(node);		/* Signal ng_rmnode we are persisant */
703 
704 	return (0);
705 }
706 
707 /*
708  * Hook disconnection.
709  */
710 static int
711 ng_ether_disconnect(hook_p hook)
712 {
713 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
714 
715 	if (hook == priv->upper) {
716 		priv->upper = NULL;
717 		if (priv->ifp != NULL)		/* restore h/w csum */
718 			priv->ifp->if_hwassist = priv->hwassist;
719 	} else if (hook == priv->lower)
720 		priv->lower = NULL;
721 	else if (hook == priv->orphan)
722 		priv->orphan = NULL;
723 	else
724 		panic("%s: weird hook", __func__);
725 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
726 	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
727 		ng_rmnode_self(NG_HOOK_NODE(hook));	/* reset node */
728 	return (0);
729 }
730 
731 /******************************************************************
732 		    	INITIALIZATION
733 ******************************************************************/
734 
735 /*
736  * Handle loading and unloading for this node type.
737  */
738 static int
739 ng_ether_mod_event(module_t mod, int event, void *data)
740 {
741 	struct ifnet *ifp;
742 	int error = 0;
743 	int s;
744 
745 	s = splnet();
746 	switch (event) {
747 	case MOD_LOAD:
748 
749 		/* Register function hooks */
750 		if (ng_ether_attach_p != NULL) {
751 			error = EEXIST;
752 			break;
753 		}
754 		ng_ether_attach_p = ng_ether_attach;
755 		ng_ether_detach_p = ng_ether_detach;
756 		ng_ether_output_p = ng_ether_output;
757 		ng_ether_input_p = ng_ether_input;
758 		ng_ether_input_orphan_p = ng_ether_input_orphan;
759 		ng_ether_link_state_p = ng_ether_link_state;
760 
761 		/* Create nodes for any already-existing Ethernet interfaces */
762 		IFNET_RLOCK();
763 		TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
764 			if (ifp->if_type == IFT_ETHER
765 			    || ifp->if_type == IFT_L2VLAN)
766 				ng_ether_attach(ifp);
767 		}
768 		IFNET_RUNLOCK();
769 		break;
770 
771 	case MOD_UNLOAD:
772 
773 		/*
774 		 * Note that the base code won't try to unload us until
775 		 * all nodes have been removed, and that can't happen
776 		 * until all Ethernet interfaces are removed. In any
777 		 * case, we know there are no nodes left if the action
778 		 * is MOD_UNLOAD, so there's no need to detach any nodes.
779 		 */
780 
781 		/* Unregister function hooks */
782 		ng_ether_attach_p = NULL;
783 		ng_ether_detach_p = NULL;
784 		ng_ether_output_p = NULL;
785 		ng_ether_input_p = NULL;
786 		ng_ether_input_orphan_p = NULL;
787 		ng_ether_link_state_p = NULL;
788 		break;
789 
790 	default:
791 		error = EOPNOTSUPP;
792 		break;
793 	}
794 	splx(s);
795 	return (error);
796 }
797 
798