xref: /freebsd/sys/netgraph/ng_ether.c (revision d37ea99837e6ad50837fd9fe1771ddf1c3ba6002)
1 
2 /*
3  * ng_ether.c
4  *
5  * Copyright (c) 1996-2000 Whistle Communications, Inc.
6  * All rights reserved.
7  *
8  * Subject to the following obligations and disclaimer of warranty, use and
9  * redistribution of this software, in source or object code forms, with or
10  * without modifications are expressly permitted by Whistle Communications;
11  * provided, however, that:
12  * 1. Any and all reproductions of the source or object code must include the
13  *    copyright notice above and the following disclaimer of warranties; and
14  * 2. No rights are granted, in any manner or form, to use Whistle
15  *    Communications, Inc. trademarks, including the mark "WHISTLE
16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17  *    such appears in the above copyright notice or in the software.
18  *
19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35  * OF SUCH DAMAGE.
36  *
37  * Authors: Archie Cobbs <archie@freebsd.org>
38  *	    Julian Elischer <julian@freebsd.org>
39  *
40  * $FreeBSD$
41  */
42 
43 /*
44  * ng_ether(4) netgraph node type
45  */
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/errno.h>
53 #include <sys/syslog.h>
54 #include <sys/socket.h>
55 
56 #include <net/if.h>
57 #include <net/if_types.h>
58 #include <net/if_arp.h>
59 #include <net/if_var.h>
60 #include <net/ethernet.h>
61 
62 #include <netgraph/ng_message.h>
63 #include <netgraph/netgraph.h>
64 #include <netgraph/ng_parse.h>
65 #include <netgraph/ng_ether.h>
66 
67 #define IFP2NG(ifp)  ((struct ng_node *)((struct arpcom *)(ifp))->ac_netgraph)
68 
69 /* Per-node private data */
70 struct private {
71 	struct ifnet	*ifp;		/* associated interface */
72 	hook_p		upper;		/* upper hook connection */
73 	hook_p		lower;		/* lower hook connection */
74 	hook_p		orphan;		/* orphan hook connection */
75 	u_char		autoSrcAddr;	/* always overwrite source address */
76 	u_char		promisc;	/* promiscuous mode enabled */
77 	u_long		hwassist;	/* hardware checksum capabilities */
78 	u_int		flags;		/* flags e.g. really die */
79 };
80 typedef struct private *priv_p;
81 
82 /* Hook pointers used by if_ethersubr.c to callback to netgraph */
83 extern	void	(*ng_ether_input_p)(struct ifnet *ifp, struct mbuf **mp);
84 extern	void	(*ng_ether_input_orphan_p)(struct ifnet *ifp, struct mbuf *m);
85 extern	int	(*ng_ether_output_p)(struct ifnet *ifp, struct mbuf **mp);
86 extern	void	(*ng_ether_attach_p)(struct ifnet *ifp);
87 extern	void	(*ng_ether_detach_p)(struct ifnet *ifp);
88 
89 /* Functional hooks called from if_ethersubr.c */
90 static void	ng_ether_input(struct ifnet *ifp, struct mbuf **mp);
91 static void	ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m);
92 static int	ng_ether_output(struct ifnet *ifp, struct mbuf **mp);
93 static void	ng_ether_attach(struct ifnet *ifp);
94 static void	ng_ether_detach(struct ifnet *ifp);
95 
96 /* Other functions */
97 static int	ng_ether_rcv_lower(node_p node, struct mbuf *m);
98 static int	ng_ether_rcv_upper(node_p node, struct mbuf *m);
99 
100 /* Netgraph node methods */
101 static ng_constructor_t	ng_ether_constructor;
102 static ng_rcvmsg_t	ng_ether_rcvmsg;
103 static ng_shutdown_t	ng_ether_shutdown;
104 static ng_newhook_t	ng_ether_newhook;
105 static ng_connect_t	ng_ether_connect;
106 static ng_rcvdata_t	ng_ether_rcvdata;
107 static ng_disconnect_t	ng_ether_disconnect;
108 static int		ng_ether_mod_event(module_t mod, int event, void *data);
109 
110 /* List of commands and how to convert arguments to/from ASCII */
111 static const struct ng_cmdlist ng_ether_cmdlist[] = {
112 	{
113 	  NGM_ETHER_COOKIE,
114 	  NGM_ETHER_GET_IFNAME,
115 	  "getifname",
116 	  NULL,
117 	  &ng_parse_string_type
118 	},
119 	{
120 	  NGM_ETHER_COOKIE,
121 	  NGM_ETHER_GET_IFINDEX,
122 	  "getifindex",
123 	  NULL,
124 	  &ng_parse_int32_type
125 	},
126 	{
127 	  NGM_ETHER_COOKIE,
128 	  NGM_ETHER_GET_ENADDR,
129 	  "getenaddr",
130 	  NULL,
131 	  &ng_parse_enaddr_type
132 	},
133 	{
134 	  NGM_ETHER_COOKIE,
135 	  NGM_ETHER_SET_ENADDR,
136 	  "setenaddr",
137 	  &ng_parse_enaddr_type,
138 	  NULL
139 	},
140 	{
141 	  NGM_ETHER_COOKIE,
142 	  NGM_ETHER_GET_PROMISC,
143 	  "getpromisc",
144 	  NULL,
145 	  &ng_parse_int32_type
146 	},
147 	{
148 	  NGM_ETHER_COOKIE,
149 	  NGM_ETHER_SET_PROMISC,
150 	  "setpromisc",
151 	  &ng_parse_int32_type,
152 	  NULL
153 	},
154 	{
155 	  NGM_ETHER_COOKIE,
156 	  NGM_ETHER_GET_AUTOSRC,
157 	  "getautosrc",
158 	  NULL,
159 	  &ng_parse_int32_type
160 	},
161 	{
162 	  NGM_ETHER_COOKIE,
163 	  NGM_ETHER_SET_AUTOSRC,
164 	  "setautosrc",
165 	  &ng_parse_int32_type,
166 	  NULL
167 	},
168 	{ 0 }
169 };
170 
171 static struct ng_type ng_ether_typestruct = {
172 	.version =	NG_ABI_VERSION,
173 	.name =		NG_ETHER_NODE_TYPE,
174 	.mod_event =	ng_ether_mod_event,
175 	.constructor =	ng_ether_constructor,
176 	.rcvmsg =	ng_ether_rcvmsg,
177 	.shutdown =	ng_ether_shutdown,
178 	.newhook =	ng_ether_newhook,
179 	.connect =	ng_ether_connect,
180 	.rcvdata =	ng_ether_rcvdata,
181 	.disconnect =	ng_ether_disconnect,
182 	.cmdlist =	ng_ether_cmdlist,
183 };
184 MODULE_VERSION(ng_ether, 1);
185 NETGRAPH_INIT(ether, &ng_ether_typestruct);
186 
187 /******************************************************************
188 		    ETHERNET FUNCTION HOOKS
189 ******************************************************************/
190 
191 /*
192  * Handle a packet that has come in on an interface. We get to
193  * look at it here before any upper layer protocols do.
194  *
195  * NOTE: this function will get called at splimp()
196  */
197 static void
198 ng_ether_input(struct ifnet *ifp, struct mbuf **mp)
199 {
200 	const node_p node = IFP2NG(ifp);
201 	const priv_p priv = NG_NODE_PRIVATE(node);
202 	int error;
203 
204 	/* If "lower" hook not connected, let packet continue */
205 	if (priv->lower == NULL)
206 		return;
207 	NG_SEND_DATA_ONLY(error, priv->lower, *mp);	/* sets *mp = NULL */
208 }
209 
210 /*
211  * Handle a packet that has come in on an interface, and which
212  * does not match any of our known protocols (an ``orphan'').
213  *
214  * NOTE: this function will get called at splimp()
215  */
216 static void
217 ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m)
218 {
219 	const node_p node = IFP2NG(ifp);
220 	const priv_p priv = NG_NODE_PRIVATE(node);
221 	int error;
222 
223 	/* If "orphan" hook not connected, discard packet */
224 	if (priv->orphan == NULL) {
225 		m_freem(m);
226 		return;
227 	}
228 	NG_SEND_DATA_ONLY(error, priv->orphan, m);
229 }
230 
231 /*
232  * Handle a packet that is going out on an interface.
233  * The Ethernet header is already attached to the mbuf.
234  */
235 static int
236 ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
237 {
238 	const node_p node = IFP2NG(ifp);
239 	const priv_p priv = NG_NODE_PRIVATE(node);
240 	int error = 0;
241 
242 	/* If "upper" hook not connected, let packet continue */
243 	if (priv->upper == NULL)
244 		return (0);
245 
246 	/* Send it out "upper" hook */
247 	NG_SEND_DATA_ONLY(error, priv->upper, *mp);
248 	return (error);
249 }
250 
251 /*
252  * A new Ethernet interface has been attached.
253  * Create a new node for it, etc.
254  */
255 static void
256 ng_ether_attach(struct ifnet *ifp)
257 {
258 	priv_p priv;
259 	node_p node;
260 
261 	/* Create node */
262 	KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __func__));
263 	if (ng_make_node_common(&ng_ether_typestruct, &node) != 0) {
264 		log(LOG_ERR, "%s: can't %s for %s\n",
265 		    __func__, "create node", ifp->if_xname);
266 		return;
267 	}
268 
269 	/* Allocate private data */
270 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
271 	if (priv == NULL) {
272 		log(LOG_ERR, "%s: can't %s for %s\n",
273 		    __func__, "allocate memory", ifp->if_xname);
274 		NG_NODE_UNREF(node);
275 		return;
276 	}
277 	NG_NODE_SET_PRIVATE(node, priv);
278 	priv->ifp = ifp;
279 	IFP2NG(ifp) = node;
280 	priv->autoSrcAddr = 1;
281 	priv->hwassist = ifp->if_hwassist;
282 
283 	/* Try to give the node the same name as the interface */
284 	if (ng_name_node(node, ifp->if_xname) != 0) {
285 		log(LOG_WARNING, "%s: can't name node %s\n",
286 		    __func__, ifp->if_xname);
287 	}
288 }
289 
290 /*
291  * An Ethernet interface is being detached.
292  * REALLY Destroy its node.
293  */
294 static void
295 ng_ether_detach(struct ifnet *ifp)
296 {
297 	const node_p node = IFP2NG(ifp);
298 	const priv_p priv = NG_NODE_PRIVATE(node);
299 
300 	if (node == NULL)		/* no node (why not?), ignore */
301 		return;
302 	NG_NODE_REALLY_DIE(node);	/* Force real removal of node */
303 	/*
304 	 * We can't assume the ifnet is still around when we run shutdown
305 	 * So zap it now. XXX We HOPE that anything running at this time
306 	 * handles it (as it should in the non netgraph case).
307 	 */
308 	IFP2NG(ifp) = NULL;
309 	priv->ifp = NULL;	/* XXX race if interrupted an output packet */
310 	ng_rmnode_self(node);		/* remove all netgraph parts */
311 }
312 
313 /******************************************************************
314 		    NETGRAPH NODE METHODS
315 ******************************************************************/
316 
317 /*
318  * It is not possible or allowable to create a node of this type.
319  * Nodes get created when the interface is attached (or, when
320  * this node type's KLD is loaded).
321  */
322 static int
323 ng_ether_constructor(node_p node)
324 {
325 	return (EINVAL);
326 }
327 
328 /*
329  * Check for attaching a new hook.
330  */
331 static	int
332 ng_ether_newhook(node_p node, hook_p hook, const char *name)
333 {
334 	const priv_p priv = NG_NODE_PRIVATE(node);
335 	hook_p *hookptr;
336 
337 	/* Divert hook is an alias for lower */
338 	if (strcmp(name, NG_ETHER_HOOK_DIVERT) == 0)
339 		name = NG_ETHER_HOOK_LOWER;
340 
341 	/* Which hook? */
342 	if (strcmp(name, NG_ETHER_HOOK_UPPER) == 0)
343 		hookptr = &priv->upper;
344 	else if (strcmp(name, NG_ETHER_HOOK_LOWER) == 0)
345 		hookptr = &priv->lower;
346 	else if (strcmp(name, NG_ETHER_HOOK_ORPHAN) == 0)
347 		hookptr = &priv->orphan;
348 	else
349 		return (EINVAL);
350 
351 	/* Check if already connected (shouldn't be, but doesn't hurt) */
352 	if (*hookptr != NULL)
353 		return (EISCONN);
354 
355 	/* Disable hardware checksums while 'upper' hook is connected */
356 	if (hookptr == &priv->upper)
357 		priv->ifp->if_hwassist = 0;
358 
359 	/* OK */
360 	*hookptr = hook;
361 	return (0);
362 }
363 
364 /*
365  * Hooks are attached, adjust to force queueing.
366  * We don't really care which hook it is.
367  * they should all be queuing for outgoing data.
368  */
369 static	int
370 ng_ether_connect(hook_p hook)
371 {
372 	NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
373 	return (0);
374 }
375 
376 /*
377  * Receive an incoming control message.
378  */
379 static int
380 ng_ether_rcvmsg(node_p node, item_p item, hook_p lasthook)
381 {
382 	const priv_p priv = NG_NODE_PRIVATE(node);
383 	struct ng_mesg *resp = NULL;
384 	int error = 0;
385 	struct ng_mesg *msg;
386 
387 	NGI_GET_MSG(item, msg);
388 	switch (msg->header.typecookie) {
389 	case NGM_ETHER_COOKIE:
390 		switch (msg->header.cmd) {
391 		case NGM_ETHER_GET_IFNAME:
392 			NG_MKRESPONSE(resp, msg, IFNAMSIZ + 1, M_NOWAIT);
393 			if (resp == NULL) {
394 				error = ENOMEM;
395 				break;
396 			}
397 			strlcpy(resp->data, priv->ifp->if_xname, IFNAMSIZ + 1);
398 			break;
399 		case NGM_ETHER_GET_IFINDEX:
400 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
401 			if (resp == NULL) {
402 				error = ENOMEM;
403 				break;
404 			}
405 			*((u_int32_t *)resp->data) = priv->ifp->if_index;
406 			break;
407 		case NGM_ETHER_GET_ENADDR:
408 			NG_MKRESPONSE(resp, msg, ETHER_ADDR_LEN, M_NOWAIT);
409 			if (resp == NULL) {
410 				error = ENOMEM;
411 				break;
412 			}
413 			bcopy((IFP2AC(priv->ifp))->ac_enaddr,
414 			    resp->data, ETHER_ADDR_LEN);
415 			break;
416 		case NGM_ETHER_SET_ENADDR:
417 		    {
418 			if (msg->header.arglen != ETHER_ADDR_LEN) {
419 				error = EINVAL;
420 				break;
421 			}
422 			error = if_setlladdr(priv->ifp,
423 			    (u_char *)msg->data, ETHER_ADDR_LEN);
424 			break;
425 		    }
426 		case NGM_ETHER_GET_PROMISC:
427 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
428 			if (resp == NULL) {
429 				error = ENOMEM;
430 				break;
431 			}
432 			*((u_int32_t *)resp->data) = priv->promisc;
433 			break;
434 		case NGM_ETHER_SET_PROMISC:
435 		    {
436 			u_char want;
437 
438 			if (msg->header.arglen != sizeof(u_int32_t)) {
439 				error = EINVAL;
440 				break;
441 			}
442 			want = !!*((u_int32_t *)msg->data);
443 			if (want ^ priv->promisc) {
444 				if ((error = ifpromisc(priv->ifp, want)) != 0)
445 					break;
446 				priv->promisc = want;
447 			}
448 			break;
449 		    }
450 		case NGM_ETHER_GET_AUTOSRC:
451 			NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
452 			if (resp == NULL) {
453 				error = ENOMEM;
454 				break;
455 			}
456 			*((u_int32_t *)resp->data) = priv->autoSrcAddr;
457 			break;
458 		case NGM_ETHER_SET_AUTOSRC:
459 			if (msg->header.arglen != sizeof(u_int32_t)) {
460 				error = EINVAL;
461 				break;
462 			}
463 			priv->autoSrcAddr = !!*((u_int32_t *)msg->data);
464 			break;
465 		default:
466 			error = EINVAL;
467 			break;
468 		}
469 		break;
470 	default:
471 		error = EINVAL;
472 		break;
473 	}
474 	NG_RESPOND_MSG(error, node, item, resp);
475 	NG_FREE_MSG(msg);
476 	return (error);
477 }
478 
479 /*
480  * Receive data on a hook.
481  */
482 static int
483 ng_ether_rcvdata(hook_p hook, item_p item)
484 {
485 	const node_p node = NG_HOOK_NODE(hook);
486 	const priv_p priv = NG_NODE_PRIVATE(node);
487 	struct mbuf *m;
488 
489 	NGI_GET_M(item, m);
490 	NG_FREE_ITEM(item);
491 
492 	if (hook == priv->lower || hook == priv->orphan)
493 		return ng_ether_rcv_lower(node, m);
494 	if (hook == priv->upper)
495 		return ng_ether_rcv_upper(node, m);
496 	panic("%s: weird hook", __func__);
497 #ifdef RESTARTABLE_PANICS /* so we don't get an error msg in LINT */
498 	return NULL;
499 #endif
500 }
501 
502 /*
503  * Handle an mbuf received on the "lower" or "orphan" hook.
504  */
505 static int
506 ng_ether_rcv_lower(node_p node, struct mbuf *m)
507 {
508 	const priv_p priv = NG_NODE_PRIVATE(node);
509  	struct ifnet *const ifp = priv->ifp;
510 
511 	/* Check whether interface is ready for packets */
512 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
513 		NG_FREE_M(m);
514 		return (ENETDOWN);
515 	}
516 
517 	/* Make sure header is fully pulled up */
518 	if (m->m_pkthdr.len < sizeof(struct ether_header)) {
519 		NG_FREE_M(m);
520 		return (EINVAL);
521 	}
522 	if (m->m_len < sizeof(struct ether_header)
523 	    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
524 		return (ENOBUFS);
525 
526 	/* Drop in the MAC address if desired */
527 	if (priv->autoSrcAddr) {
528 
529 		/* Make the mbuf writable if it's not already */
530 		if (!M_WRITABLE(m)
531 		    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
532 			return (ENOBUFS);
533 
534 		/* Overwrite source MAC address */
535 		bcopy((IFP2AC(ifp))->ac_enaddr,
536 		    mtod(m, struct ether_header *)->ether_shost,
537 		    ETHER_ADDR_LEN);
538 	}
539 
540 	/* Send it on its way */
541 	return ether_output_frame(ifp, m);
542 }
543 
544 /*
545  * Handle an mbuf received on the "upper" hook.
546  */
547 static int
548 ng_ether_rcv_upper(node_p node, struct mbuf *m)
549 {
550 	const priv_p priv = NG_NODE_PRIVATE(node);
551 
552 	m->m_pkthdr.rcvif = priv->ifp;
553 
554 	/* Route packet back in */
555 	ether_demux(priv->ifp, m);
556 	return (0);
557 }
558 
559 /*
560  * Shutdown node. This resets the node but does not remove it
561  * unless the REALLY_DIE flag is set.
562  */
563 static int
564 ng_ether_shutdown(node_p node)
565 {
566 	const priv_p priv = NG_NODE_PRIVATE(node);
567 
568 	if (node->nd_flags & NG_REALLY_DIE) {
569 		/*
570 		 * WE came here because the ethernet card is being unloaded,
571 		 * so stop being persistant.
572 		 * Actually undo all the things we did on creation.
573 		 * Assume the ifp has already been freed.
574 		 */
575 		NG_NODE_SET_PRIVATE(node, NULL);
576 		FREE(priv, M_NETGRAPH);
577 		NG_NODE_UNREF(node);	/* free node itself */
578 		return (0);
579 	}
580 	if (priv->promisc) {		/* disable promiscuous mode */
581 		(void)ifpromisc(priv->ifp, 0);
582 		priv->promisc = 0;
583 	}
584 	priv->autoSrcAddr = 1;		/* reset auto-src-addr flag */
585 	node->nd_flags &= ~NG_INVALID;	/* Signal ng_rmnode we are persisant */
586 	return (0);
587 }
588 
589 /*
590  * Hook disconnection.
591  */
592 static int
593 ng_ether_disconnect(hook_p hook)
594 {
595 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
596 
597 	if (hook == priv->upper) {
598 		priv->upper = NULL;
599 		if (priv->ifp != NULL)		/* restore h/w csum */
600 			priv->ifp->if_hwassist = priv->hwassist;
601 	} else if (hook == priv->lower)
602 		priv->lower = NULL;
603 	else if (hook == priv->orphan)
604 		priv->orphan = NULL;
605 	else
606 		panic("%s: weird hook", __func__);
607 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
608 	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
609 		ng_rmnode_self(NG_HOOK_NODE(hook));	/* reset node */
610 	return (0);
611 }
612 
613 /******************************************************************
614 		    	INITIALIZATION
615 ******************************************************************/
616 
617 /*
618  * Handle loading and unloading for this node type.
619  */
620 static int
621 ng_ether_mod_event(module_t mod, int event, void *data)
622 {
623 	struct ifnet *ifp;
624 	int error = 0;
625 	int s;
626 
627 	s = splnet();
628 	switch (event) {
629 	case MOD_LOAD:
630 
631 		/* Register function hooks */
632 		if (ng_ether_attach_p != NULL) {
633 			error = EEXIST;
634 			break;
635 		}
636 		ng_ether_attach_p = ng_ether_attach;
637 		ng_ether_detach_p = ng_ether_detach;
638 		ng_ether_output_p = ng_ether_output;
639 		ng_ether_input_p = ng_ether_input;
640 		ng_ether_input_orphan_p = ng_ether_input_orphan;
641 
642 		/* Create nodes for any already-existing Ethernet interfaces */
643 		IFNET_RLOCK();
644 		TAILQ_FOREACH(ifp, &ifnet, if_link) {
645 			if (ifp->if_type == IFT_ETHER
646 			    || ifp->if_type == IFT_L2VLAN)
647 				ng_ether_attach(ifp);
648 		}
649 		IFNET_RUNLOCK();
650 		break;
651 
652 	case MOD_UNLOAD:
653 
654 		/*
655 		 * Note that the base code won't try to unload us until
656 		 * all nodes have been removed, and that can't happen
657 		 * until all Ethernet interfaces are removed. In any
658 		 * case, we know there are no nodes left if the action
659 		 * is MOD_UNLOAD, so there's no need to detach any nodes.
660 		 */
661 
662 		/* Unregister function hooks */
663 		ng_ether_attach_p = NULL;
664 		ng_ether_detach_p = NULL;
665 		ng_ether_output_p = NULL;
666 		ng_ether_input_p = NULL;
667 		ng_ether_input_orphan_p = NULL;
668 		break;
669 
670 	default:
671 		error = EOPNOTSUPP;
672 		break;
673 	}
674 	splx(s);
675 	return (error);
676 }
677 
678