xref: /freebsd/sys/netgraph/ng_ether.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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 "opt_route.h"
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/kernel.h>
54 #include <sys/malloc.h>
55 #include <sys/mbuf.h>
56 #include <sys/errno.h>
57 #include <sys/syslog.h>
58 #include <sys/socket.h>
59 #include <sys/vimage.h>
60 
61 #include <net/if.h>
62 #include <net/if_dl.h>
63 #include <net/if_types.h>
64 #include <net/if_arp.h>
65 #include <net/if_var.h>
66 #include <net/ethernet.h>
67 #include <net/if_bridgevar.h>
68 #include <net/route.h>
69 #include <net/vnet.h>
70 
71 #include <netgraph/ng_message.h>
72 #include <netgraph/netgraph.h>
73 #include <netgraph/ng_parse.h>
74 #include <netgraph/ng_ether.h>
75 
76 #define IFP2NG(ifp)  (IFP2AC((ifp))->ac_netgraph)
77 
78 /* Per-node private data */
79 struct private {
80 	struct ifnet	*ifp;		/* associated interface */
81 	hook_p		upper;		/* upper hook connection */
82 	hook_p		lower;		/* lower hook connection */
83 	hook_p		orphan;		/* orphan hook connection */
84 	u_char		autoSrcAddr;	/* always overwrite source address */
85 	u_char		promisc;	/* promiscuous mode enabled */
86 	u_long		hwassist;	/* hardware checksum capabilities */
87 	u_int		flags;		/* flags e.g. really die */
88 };
89 typedef struct private *priv_p;
90 
91 /* Hook pointers used by if_ethersubr.c to callback to netgraph */
92 extern	void	(*ng_ether_input_p)(struct ifnet *ifp, struct mbuf **mp);
93 extern	void	(*ng_ether_input_orphan_p)(struct ifnet *ifp, struct mbuf *m);
94 extern	int	(*ng_ether_output_p)(struct ifnet *ifp, struct mbuf **mp);
95 extern	void	(*ng_ether_attach_p)(struct ifnet *ifp);
96 extern	void	(*ng_ether_detach_p)(struct ifnet *ifp);
97 extern	void	(*ng_ether_link_state_p)(struct ifnet *ifp, int state);
98 
99 /* Functional hooks called from if_ethersubr.c */
100 static void	ng_ether_input(struct ifnet *ifp, struct mbuf **mp);
101 static void	ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m);
102 static int	ng_ether_output(struct ifnet *ifp, struct mbuf **mp);
103 static void	ng_ether_attach(struct ifnet *ifp);
104 static void	ng_ether_detach(struct ifnet *ifp);
105 static void	ng_ether_link_state(struct ifnet *ifp, int state);
106 
107 /* Other functions */
108 static int	ng_ether_rcv_lower(hook_p node, item_p item);
109 static int	ng_ether_rcv_upper(hook_p node, item_p item);
110 
111 /* Netgraph node methods */
112 static ng_constructor_t	ng_ether_constructor;
113 static ng_rcvmsg_t	ng_ether_rcvmsg;
114 static ng_shutdown_t	ng_ether_shutdown;
115 static ng_newhook_t	ng_ether_newhook;
116 static ng_rcvdata_t	ng_ether_rcvdata;
117 static ng_disconnect_t	ng_ether_disconnect;
118 static int		ng_ether_mod_event(module_t mod, int event, void *data);
119 
120 /* List of commands and how to convert arguments to/from ASCII */
121 static const struct ng_cmdlist ng_ether_cmdlist[] = {
122 	{
123 	  NGM_ETHER_COOKIE,
124 	  NGM_ETHER_GET_IFNAME,
125 	  "getifname",
126 	  NULL,
127 	  &ng_parse_string_type
128 	},
129 	{
130 	  NGM_ETHER_COOKIE,
131 	  NGM_ETHER_GET_IFINDEX,
132 	  "getifindex",
133 	  NULL,
134 	  &ng_parse_int32_type
135 	},
136 	{
137 	  NGM_ETHER_COOKIE,
138 	  NGM_ETHER_GET_ENADDR,
139 	  "getenaddr",
140 	  NULL,
141 	  &ng_parse_enaddr_type
142 	},
143 	{
144 	  NGM_ETHER_COOKIE,
145 	  NGM_ETHER_SET_ENADDR,
146 	  "setenaddr",
147 	  &ng_parse_enaddr_type,
148 	  NULL
149 	},
150 	{
151 	  NGM_ETHER_COOKIE,
152 	  NGM_ETHER_GET_PROMISC,
153 	  "getpromisc",
154 	  NULL,
155 	  &ng_parse_int32_type
156 	},
157 	{
158 	  NGM_ETHER_COOKIE,
159 	  NGM_ETHER_SET_PROMISC,
160 	  "setpromisc",
161 	  &ng_parse_int32_type,
162 	  NULL
163 	},
164 	{
165 	  NGM_ETHER_COOKIE,
166 	  NGM_ETHER_GET_AUTOSRC,
167 	  "getautosrc",
168 	  NULL,
169 	  &ng_parse_int32_type
170 	},
171 	{
172 	  NGM_ETHER_COOKIE,
173 	  NGM_ETHER_SET_AUTOSRC,
174 	  "setautosrc",
175 	  &ng_parse_int32_type,
176 	  NULL
177 	},
178 	{
179 	  NGM_ETHER_COOKIE,
180 	  NGM_ETHER_ADD_MULTI,
181 	  "addmulti",
182 	  &ng_parse_enaddr_type,
183 	  NULL
184 	},
185 	{
186 	  NGM_ETHER_COOKIE,
187 	  NGM_ETHER_DEL_MULTI,
188 	  "delmulti",
189 	  &ng_parse_enaddr_type,
190 	  NULL
191 	},
192 	{
193 	  NGM_ETHER_COOKIE,
194 	  NGM_ETHER_DETACH,
195 	  "detach",
196 	  NULL,
197 	  NULL
198 	},
199 	{ 0 }
200 };
201 
202 static struct ng_type ng_ether_typestruct = {
203 	.version =	NG_ABI_VERSION,
204 	.name =		NG_ETHER_NODE_TYPE,
205 	.mod_event =	ng_ether_mod_event,
206 	.constructor =	ng_ether_constructor,
207 	.rcvmsg =	ng_ether_rcvmsg,
208 	.shutdown =	ng_ether_shutdown,
209 	.newhook =	ng_ether_newhook,
210 	.rcvdata =	ng_ether_rcvdata,
211 	.disconnect =	ng_ether_disconnect,
212 	.cmdlist =	ng_ether_cmdlist,
213 };
214 NETGRAPH_INIT(ether, &ng_ether_typestruct);
215 
216 /******************************************************************
217 		    ETHERNET FUNCTION HOOKS
218 ******************************************************************/
219 
220 /*
221  * Handle a packet that has come in on an interface. We get to
222  * look at it here before any upper layer protocols do.
223  *
224  * NOTE: this function will get called at splimp()
225  */
226 static void
227 ng_ether_input(struct ifnet *ifp, struct mbuf **mp)
228 {
229 	const node_p node = IFP2NG(ifp);
230 	const priv_p priv = NG_NODE_PRIVATE(node);
231 	int error;
232 
233 	/* If "lower" hook not connected, let packet continue */
234 	if (priv->lower == NULL)
235 		return;
236 	NG_SEND_DATA_ONLY(error, priv->lower, *mp);	/* sets *mp = NULL */
237 }
238 
239 /*
240  * Handle a packet that has come in on an interface, and which
241  * does not match any of our known protocols (an ``orphan'').
242  *
243  * NOTE: this function will get called at splimp()
244  */
245 static void
246 ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m)
247 {
248 	const node_p node = IFP2NG(ifp);
249 	const priv_p priv = NG_NODE_PRIVATE(node);
250 	int error;
251 
252 	/* If "orphan" hook not connected, discard packet */
253 	if (priv->orphan == NULL) {
254 		m_freem(m);
255 		return;
256 	}
257 	NG_SEND_DATA_ONLY(error, priv->orphan, m);
258 }
259 
260 /*
261  * Handle a packet that is going out on an interface.
262  * The Ethernet header is already attached to the mbuf.
263  */
264 static int
265 ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
266 {
267 	const node_p node = IFP2NG(ifp);
268 	const priv_p priv = NG_NODE_PRIVATE(node);
269 	int error = 0;
270 
271 	/* If "upper" hook not connected, let packet continue */
272 	if (priv->upper == NULL)
273 		return (0);
274 
275 	/* Send it out "upper" hook */
276 	NG_SEND_DATA_ONLY(error, priv->upper, *mp);
277 	return (error);
278 }
279 
280 /*
281  * A new Ethernet interface has been attached.
282  * Create a new node for it, etc.
283  */
284 static void
285 ng_ether_attach(struct ifnet *ifp)
286 {
287 	priv_p priv;
288 	node_p node;
289 
290 	/* Create node */
291 	KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __func__));
292 	if (ng_make_node_common(&ng_ether_typestruct, &node) != 0) {
293 		log(LOG_ERR, "%s: can't %s for %s\n",
294 		    __func__, "create node", ifp->if_xname);
295 		return;
296 	}
297 
298 	/* Allocate private data */
299 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
300 	if (priv == NULL) {
301 		log(LOG_ERR, "%s: can't %s for %s\n",
302 		    __func__, "allocate memory", ifp->if_xname);
303 		NG_NODE_UNREF(node);
304 		return;
305 	}
306 	NG_NODE_SET_PRIVATE(node, priv);
307 	priv->ifp = ifp;
308 	IFP2NG(ifp) = node;
309 	priv->hwassist = ifp->if_hwassist;
310 
311 	/* Try to give the node the same name as the interface */
312 	if (ng_name_node(node, ifp->if_xname) != 0) {
313 		log(LOG_WARNING, "%s: can't name node %s\n",
314 		    __func__, ifp->if_xname);
315 	}
316 }
317 
318 /*
319  * An Ethernet interface is being detached.
320  * REALLY Destroy its node.
321  */
322 static void
323 ng_ether_detach(struct ifnet *ifp)
324 {
325 	const node_p node = IFP2NG(ifp);
326 	const priv_p priv = NG_NODE_PRIVATE(node);
327 
328 	NG_NODE_REALLY_DIE(node);	/* Force real removal of node */
329 	/*
330 	 * We can't assume the ifnet is still around when we run shutdown
331 	 * So zap it now. XXX We HOPE that anything running at this time
332 	 * handles it (as it should in the non netgraph case).
333 	 */
334 	IFP2NG(ifp) = NULL;
335 	priv->ifp = NULL;	/* XXX race if interrupted an output packet */
336 	ng_rmnode_self(node);		/* remove all netgraph parts */
337 }
338 
339 /*
340  * Notify graph about link event.
341  * if_link_state_change() has already checked that the state has changed.
342  */
343 static void
344 ng_ether_link_state(struct ifnet *ifp, int state)
345 {
346 	const node_p node = IFP2NG(ifp);
347 	const priv_p priv = NG_NODE_PRIVATE(node);
348 	struct ng_mesg *msg;
349 	int cmd, dummy_error = 0;
350 
351 	if (priv->lower == NULL)
352                 return;
353 
354 	if (state == LINK_STATE_UP)
355 		cmd = NGM_LINK_IS_UP;
356 	else if (state == LINK_STATE_DOWN)
357 		cmd = NGM_LINK_IS_DOWN;
358 	else
359 		return;
360 
361 	NG_MKMESSAGE(msg, NGM_FLOW_COOKIE, cmd, 0, M_NOWAIT);
362 	if (msg != NULL)
363 		NG_SEND_MSG_HOOK(dummy_error, node, msg, priv->lower, 0);
364 }
365 
366 /******************************************************************
367 		    NETGRAPH NODE METHODS
368 ******************************************************************/
369 
370 /*
371  * It is not possible or allowable to create a node of this type.
372  * Nodes get created when the interface is attached (or, when
373  * this node type's KLD is loaded).
374  */
375 static int
376 ng_ether_constructor(node_p node)
377 {
378 	return (EINVAL);
379 }
380 
381 /*
382  * Check for attaching a new hook.
383  */
384 static	int
385 ng_ether_newhook(node_p node, hook_p hook, const char *name)
386 {
387 	const priv_p priv = NG_NODE_PRIVATE(node);
388 	hook_p *hookptr;
389 
390 	/* Divert hook is an alias for lower */
391 	if (strcmp(name, NG_ETHER_HOOK_DIVERT) == 0)
392 		name = NG_ETHER_HOOK_LOWER;
393 
394 	/* Which hook? */
395 	if (strcmp(name, NG_ETHER_HOOK_UPPER) == 0) {
396 		hookptr = &priv->upper;
397 		NG_HOOK_SET_RCVDATA(hook, ng_ether_rcv_upper);
398 	} else if (strcmp(name, NG_ETHER_HOOK_LOWER) == 0) {
399 		hookptr = &priv->lower;
400 		NG_HOOK_SET_RCVDATA(hook, ng_ether_rcv_lower);
401 	} else if (strcmp(name, NG_ETHER_HOOK_ORPHAN) == 0) {
402 		hookptr = &priv->orphan;
403 		NG_HOOK_SET_RCVDATA(hook, ng_ether_rcv_lower);
404 	} else
405 		return (EINVAL);
406 
407 	/* Check if already connected (shouldn't be, but doesn't hurt) */
408 	if (*hookptr != NULL)
409 		return (EISCONN);
410 
411 	/* Disable hardware checksums while 'upper' hook is connected */
412 	if (hookptr == &priv->upper)
413 		priv->ifp->if_hwassist = 0;
414 
415 	/* OK */
416 	*hookptr = hook;
417 	return (0);
418 }
419 
420 /*
421  * Receive an incoming control message.
422  */
423 static int
424 ng_ether_rcvmsg(node_p node, item_p item, hook_p lasthook)
425 {
426 	const priv_p priv = NG_NODE_PRIVATE(node);
427 	struct ng_mesg *resp = NULL;
428 	int error = 0;
429 	struct ng_mesg *msg;
430 
431 	NGI_GET_MSG(item, msg);
432 	switch (msg->header.typecookie) {
433 	case NGM_ETHER_COOKIE:
434 		switch (msg->header.cmd) {
435 		case NGM_ETHER_GET_IFNAME:
436 			NG_MKRESPONSE(resp, msg, IFNAMSIZ, M_NOWAIT);
437 			if (resp == NULL) {
438 				error = ENOMEM;
439 				break;
440 			}
441 			strlcpy(resp->data, priv->ifp->if_xname, IFNAMSIZ);
442 			break;
443 		case NGM_ETHER_GET_IFINDEX:
444 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
445 			if (resp == NULL) {
446 				error = ENOMEM;
447 				break;
448 			}
449 			*((u_int32_t *)resp->data) = priv->ifp->if_index;
450 			break;
451 		case NGM_ETHER_GET_ENADDR:
452 			NG_MKRESPONSE(resp, msg, ETHER_ADDR_LEN, M_NOWAIT);
453 			if (resp == NULL) {
454 				error = ENOMEM;
455 				break;
456 			}
457 			bcopy(IF_LLADDR(priv->ifp),
458 			    resp->data, ETHER_ADDR_LEN);
459 			break;
460 		case NGM_ETHER_SET_ENADDR:
461 		    {
462 			if (msg->header.arglen != ETHER_ADDR_LEN) {
463 				error = EINVAL;
464 				break;
465 			}
466 			error = if_setlladdr(priv->ifp,
467 			    (u_char *)msg->data, ETHER_ADDR_LEN);
468 			break;
469 		    }
470 		case NGM_ETHER_GET_PROMISC:
471 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
472 			if (resp == NULL) {
473 				error = ENOMEM;
474 				break;
475 			}
476 			*((u_int32_t *)resp->data) = priv->promisc;
477 			break;
478 		case NGM_ETHER_SET_PROMISC:
479 		    {
480 			u_char want;
481 
482 			if (msg->header.arglen != sizeof(u_int32_t)) {
483 				error = EINVAL;
484 				break;
485 			}
486 			want = !!*((u_int32_t *)msg->data);
487 			if (want ^ priv->promisc) {
488 				if ((error = ifpromisc(priv->ifp, want)) != 0)
489 					break;
490 				priv->promisc = want;
491 			}
492 			break;
493 		    }
494 		case NGM_ETHER_GET_AUTOSRC:
495 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
496 			if (resp == NULL) {
497 				error = ENOMEM;
498 				break;
499 			}
500 			*((u_int32_t *)resp->data) = priv->autoSrcAddr;
501 			break;
502 		case NGM_ETHER_SET_AUTOSRC:
503 			if (msg->header.arglen != sizeof(u_int32_t)) {
504 				error = EINVAL;
505 				break;
506 			}
507 			priv->autoSrcAddr = !!*((u_int32_t *)msg->data);
508 			break;
509 		case NGM_ETHER_ADD_MULTI:
510 		    {
511 			struct sockaddr_dl sa_dl;
512 			struct ifmultiaddr *ifma;
513 
514 			if (msg->header.arglen != ETHER_ADDR_LEN) {
515 				error = EINVAL;
516 				break;
517 			}
518 			bzero(&sa_dl, sizeof(struct sockaddr_dl));
519 			sa_dl.sdl_len = sizeof(struct sockaddr_dl);
520 			sa_dl.sdl_family = AF_LINK;
521 			sa_dl.sdl_alen = ETHER_ADDR_LEN;
522 			bcopy((void *)msg->data, LLADDR(&sa_dl),
523 			    ETHER_ADDR_LEN);
524 			/*
525 			 * Netgraph is only permitted to join groups once
526 			 * via the if_addmulti() KPI, because it cannot hold
527 			 * struct ifmultiaddr * between calls. It may also
528 			 * lose a race while we check if the membership
529 			 * already exists.
530 			 */
531 			IF_ADDR_LOCK(priv->ifp);
532 			ifma = if_findmulti(priv->ifp,
533 			    (struct sockaddr *)&sa_dl);
534 			IF_ADDR_UNLOCK(priv->ifp);
535 			if (ifma != NULL) {
536 				error = EADDRINUSE;
537 			} else {
538 				error = if_addmulti(priv->ifp,
539 				    (struct sockaddr *)&sa_dl, &ifma);
540 			}
541 			break;
542 		    }
543 		case NGM_ETHER_DEL_MULTI:
544 		    {
545 			struct sockaddr_dl sa_dl;
546 
547 			if (msg->header.arglen != ETHER_ADDR_LEN) {
548 				error = EINVAL;
549 				break;
550 			}
551 			bzero(&sa_dl, sizeof(struct sockaddr_dl));
552 			sa_dl.sdl_len = sizeof(struct sockaddr_dl);
553 			sa_dl.sdl_family = AF_LINK;
554 			sa_dl.sdl_alen = ETHER_ADDR_LEN;
555 			bcopy((void *)msg->data, LLADDR(&sa_dl),
556 			    ETHER_ADDR_LEN);
557 			error = if_delmulti(priv->ifp,
558 			    (struct sockaddr *)&sa_dl);
559 			break;
560 		    }
561 		case NGM_ETHER_DETACH:
562 			ng_ether_detach(priv->ifp);
563 			break;
564 		default:
565 			error = EINVAL;
566 			break;
567 		}
568 		break;
569 	default:
570 		error = EINVAL;
571 		break;
572 	}
573 	NG_RESPOND_MSG(error, node, item, resp);
574 	NG_FREE_MSG(msg);
575 	return (error);
576 }
577 
578 /*
579  * Receive data on a hook.
580  * Since we use per-hook recveive methods this should never be called.
581  */
582 static int
583 ng_ether_rcvdata(hook_p hook, item_p item)
584 {
585 	NG_FREE_ITEM(item);
586 
587 	panic("%s: weird hook", __func__);
588 #ifdef RESTARTABLE_PANICS /* so we don't get an error msg in LINT */
589 	return (0);
590 #endif
591 }
592 
593 /*
594  * Handle an mbuf received on the "lower" or "orphan" hook.
595  */
596 static int
597 ng_ether_rcv_lower(hook_p hook, item_p item)
598 {
599 	struct mbuf *m;
600 	const node_p node = NG_HOOK_NODE(hook);
601 	const priv_p priv = NG_NODE_PRIVATE(node);
602  	struct ifnet *const ifp = priv->ifp;
603 
604 	NGI_GET_M(item, m);
605 	NG_FREE_ITEM(item);
606 
607 	/* Check whether interface is ready for packets */
608 
609 	if (!((ifp->if_flags & IFF_UP) &&
610 	    (ifp->if_drv_flags & IFF_DRV_RUNNING))) {
611 		NG_FREE_M(m);
612 		return (ENETDOWN);
613 	}
614 
615 	/* Make sure header is fully pulled up */
616 	if (m->m_pkthdr.len < sizeof(struct ether_header)) {
617 		NG_FREE_M(m);
618 		return (EINVAL);
619 	}
620 	if (m->m_len < sizeof(struct ether_header)
621 	    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
622 		return (ENOBUFS);
623 
624 	/* Drop in the MAC address if desired */
625 	if (priv->autoSrcAddr) {
626 
627 		/* Make the mbuf writable if it's not already */
628 		if (!M_WRITABLE(m)
629 		    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
630 			return (ENOBUFS);
631 
632 		/* Overwrite source MAC address */
633 		bcopy(IF_LLADDR(ifp),
634 		    mtod(m, struct ether_header *)->ether_shost,
635 		    ETHER_ADDR_LEN);
636 	}
637 
638 	/* Send it on its way */
639 	return ether_output_frame(ifp, m);
640 }
641 
642 /*
643  * Handle an mbuf received on the "upper" hook.
644  */
645 static int
646 ng_ether_rcv_upper(hook_p hook, item_p item)
647 {
648 	struct mbuf *m;
649 	const node_p node = NG_HOOK_NODE(hook);
650 	const priv_p priv = NG_NODE_PRIVATE(node);
651 	struct ifnet *ifp = priv->ifp;
652 
653 	NGI_GET_M(item, m);
654 	NG_FREE_ITEM(item);
655 
656 	/* Check length and pull off header */
657 	if (m->m_pkthdr.len < sizeof(struct ether_header)) {
658 		NG_FREE_M(m);
659 		return (EINVAL);
660 	}
661 	if (m->m_len < sizeof(struct ether_header) &&
662 	    (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
663 		return (ENOBUFS);
664 
665 	m->m_pkthdr.rcvif = ifp;
666 
667 	/* Pass the packet to the bridge, it may come back to us */
668 	if (ifp->if_bridge) {
669 		BRIDGE_INPUT(ifp, m);
670 		if (m == NULL)
671 			return (0);
672 	}
673 
674 	/* Route packet back in */
675 	ether_demux(ifp, m);
676 	return (0);
677 }
678 
679 /*
680  * Shutdown node. This resets the node but does not remove it
681  * unless the REALLY_DIE flag is set.
682  */
683 static int
684 ng_ether_shutdown(node_p node)
685 {
686 	const priv_p priv = NG_NODE_PRIVATE(node);
687 
688 	if (node->nd_flags & NGF_REALLY_DIE) {
689 		/*
690 		 * WE came here because the ethernet card is being unloaded,
691 		 * so stop being persistant.
692 		 * Actually undo all the things we did on creation.
693 		 * Assume the ifp has already been freed.
694 		 */
695 		NG_NODE_SET_PRIVATE(node, NULL);
696 		free(priv, M_NETGRAPH);
697 		NG_NODE_UNREF(node);	/* free node itself */
698 		return (0);
699 	}
700 	if (priv->promisc) {		/* disable promiscuous mode */
701 		(void)ifpromisc(priv->ifp, 0);
702 		priv->promisc = 0;
703 	}
704 	priv->autoSrcAddr = 1;		/* reset auto-src-addr flag */
705 	NG_NODE_REVIVE(node);		/* Signal ng_rmnode we are persisant */
706 
707 	return (0);
708 }
709 
710 /*
711  * Hook disconnection.
712  */
713 static int
714 ng_ether_disconnect(hook_p hook)
715 {
716 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
717 
718 	if (hook == priv->upper) {
719 		priv->upper = NULL;
720 		if (priv->ifp != NULL)		/* restore h/w csum */
721 			priv->ifp->if_hwassist = priv->hwassist;
722 	} else if (hook == priv->lower)
723 		priv->lower = NULL;
724 	else if (hook == priv->orphan)
725 		priv->orphan = NULL;
726 	else
727 		panic("%s: weird hook", __func__);
728 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
729 	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
730 		ng_rmnode_self(NG_HOOK_NODE(hook));	/* reset node */
731 	return (0);
732 }
733 
734 /******************************************************************
735 		    	INITIALIZATION
736 ******************************************************************/
737 
738 /*
739  * Handle loading and unloading for this node type.
740  */
741 static int
742 ng_ether_mod_event(module_t mod, int event, void *data)
743 {
744 	struct ifnet *ifp;
745 	int error = 0;
746 	int s;
747 
748 	s = splnet();
749 	switch (event) {
750 	case MOD_LOAD:
751 
752 		/* Register function hooks */
753 		if (ng_ether_attach_p != NULL) {
754 			error = EEXIST;
755 			break;
756 		}
757 		ng_ether_attach_p = ng_ether_attach;
758 		ng_ether_detach_p = ng_ether_detach;
759 		ng_ether_output_p = ng_ether_output;
760 		ng_ether_input_p = ng_ether_input;
761 		ng_ether_input_orphan_p = ng_ether_input_orphan;
762 		ng_ether_link_state_p = ng_ether_link_state;
763 
764 		/* Create nodes for any already-existing Ethernet interfaces */
765 		IFNET_RLOCK();
766 		TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
767 			if (ifp->if_type == IFT_ETHER
768 			    || ifp->if_type == IFT_L2VLAN)
769 				ng_ether_attach(ifp);
770 		}
771 		IFNET_RUNLOCK();
772 		break;
773 
774 	case MOD_UNLOAD:
775 
776 		/*
777 		 * Note that the base code won't try to unload us until
778 		 * all nodes have been removed, and that can't happen
779 		 * until all Ethernet interfaces are removed. In any
780 		 * case, we know there are no nodes left if the action
781 		 * is MOD_UNLOAD, so there's no need to detach any nodes.
782 		 */
783 
784 		/* Unregister function hooks */
785 		ng_ether_attach_p = NULL;
786 		ng_ether_detach_p = NULL;
787 		ng_ether_output_p = NULL;
788 		ng_ether_input_p = NULL;
789 		ng_ether_input_orphan_p = NULL;
790 		ng_ether_link_state_p = NULL;
791 		break;
792 
793 	default:
794 		error = EOPNOTSUPP;
795 		break;
796 	}
797 	splx(s);
798 	return (error);
799 }
800 
801