xref: /freebsd/sys/netgraph/ng_iface.c (revision 6780ab54325a71e7e70112b11657973edde8655e)
1 
2 /*
3  * ng_iface.c
4  *
5  * Copyright (c) 1996-1999 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  * Author: Archie Cobbs <archie@freebsd.org>
38  *
39  * $FreeBSD$
40  * $Whistle: ng_iface.c,v 1.33 1999/11/01 09:24:51 julian Exp $
41  */
42 
43 /*
44  * This node is also a system networking interface. It has
45  * a hook for each protocol (IP, AppleTalk, IPX, etc). Packets
46  * are simply relayed between the interface and the hooks.
47  *
48  * Interfaces are named ng0, ng1, etc.  New nodes take the
49  * first available interface name.
50  *
51  * This node also includes Berkeley packet filter support.
52  */
53 
54 #include <sys/param.h>
55 #include <sys/systm.h>
56 #include <sys/errno.h>
57 #include <sys/kernel.h>
58 #include <sys/malloc.h>
59 #include <sys/mbuf.h>
60 #include <sys/errno.h>
61 #include <sys/sockio.h>
62 #include <sys/socket.h>
63 #include <sys/syslog.h>
64 #include <sys/libkern.h>
65 
66 #include <net/if.h>
67 #include <net/if_types.h>
68 #include <net/intrq.h>
69 #include <net/bpf.h>
70 
71 #include <netinet/in.h>
72 
73 #include <netgraph/ng_message.h>
74 #include <netgraph/netgraph.h>
75 #include <netgraph/ng_parse.h>
76 #include <netgraph/ng_iface.h>
77 #include <netgraph/ng_cisco.h>
78 
79 #ifdef NG_SEPARATE_MALLOC
80 MALLOC_DEFINE(M_NETGRAPH_IFACE, "netgraph_iface", "netgraph iface node ");
81 #else
82 #define M_NETGRAPH_IFACE M_NETGRAPH
83 #endif
84 
85 /* This struct describes one address family */
86 struct iffam {
87 	sa_family_t	family;		/* Address family */
88 	const char	*hookname;	/* Name for hook */
89 };
90 typedef const struct iffam *iffam_p;
91 
92 /* List of address families supported by our interface */
93 const static struct iffam gFamilies[] = {
94 	{ AF_INET,	NG_IFACE_HOOK_INET	},
95 	{ AF_INET6,	NG_IFACE_HOOK_INET6	},
96 	{ AF_APPLETALK,	NG_IFACE_HOOK_ATALK	},
97 	{ AF_IPX,	NG_IFACE_HOOK_IPX	},
98 	{ AF_ATM,	NG_IFACE_HOOK_ATM	},
99 	{ AF_NATM,	NG_IFACE_HOOK_NATM	},
100 	{ AF_NS,	NG_IFACE_HOOK_NS	},
101 };
102 #define NUM_FAMILIES		(sizeof(gFamilies) / sizeof(*gFamilies))
103 
104 /* Node private data */
105 struct ng_iface_private {
106 	struct	ifnet *ifp;		/* Our interface */
107 	int	unit;			/* Interface unit number */
108 	node_p	node;			/* Our netgraph node */
109 	hook_p	hooks[NUM_FAMILIES];	/* Hook for each address family */
110 };
111 typedef struct ng_iface_private *priv_p;
112 
113 /* Interface methods */
114 static void	ng_iface_start(struct ifnet *ifp);
115 static int	ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
116 static int	ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
117 			struct sockaddr *dst, struct rtentry *rt0);
118 static void	ng_iface_bpftap(struct ifnet *ifp,
119 			struct mbuf *m, sa_family_t family);
120 #ifdef DEBUG
121 static void	ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
122 #endif
123 
124 /* Netgraph methods */
125 static ng_constructor_t	ng_iface_constructor;
126 static ng_rcvmsg_t	ng_iface_rcvmsg;
127 static ng_shutdown_t	ng_iface_shutdown;
128 static ng_newhook_t	ng_iface_newhook;
129 static ng_rcvdata_t	ng_iface_rcvdata;
130 static ng_disconnect_t	ng_iface_disconnect;
131 
132 /* Helper stuff */
133 static iffam_p	get_iffam_from_af(sa_family_t family);
134 static iffam_p	get_iffam_from_hook(priv_p priv, hook_p hook);
135 static iffam_p	get_iffam_from_name(const char *name);
136 static hook_p  *get_hook_from_iffam(priv_p priv, iffam_p iffam);
137 
138 /* Parse type for struct ng_iface_ifname */
139 static const struct ng_parse_fixedstring_info ng_iface_ifname_info = {
140 	NG_IFACE_IFACE_NAME_MAX + 1
141 };
142 static const struct ng_parse_type ng_iface_ifname_type = {
143 	&ng_parse_fixedstring_type,
144 	&ng_iface_ifname_info
145 };
146 
147 /* Parse type for struct ng_cisco_ipaddr */
148 static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
149 	= NG_CISCO_IPADDR_TYPE_INFO;
150 static const struct ng_parse_type ng_cisco_ipaddr_type = {
151 	&ng_parse_struct_type,
152 	&ng_cisco_ipaddr_type_fields
153 };
154 
155 /* List of commands and how to convert arguments to/from ASCII */
156 static const struct ng_cmdlist ng_iface_cmds[] = {
157 	{
158 	  NGM_IFACE_COOKIE,
159 	  NGM_IFACE_GET_IFNAME,
160 	  "getifname",
161 	  NULL,
162 	  &ng_iface_ifname_type
163 	},
164 	{
165 	  NGM_IFACE_COOKIE,
166 	  NGM_IFACE_POINT2POINT,
167 	  "point2point",
168 	  NULL,
169 	  NULL
170 	},
171 	{
172 	  NGM_IFACE_COOKIE,
173 	  NGM_IFACE_BROADCAST,
174 	  "broadcast",
175 	  NULL,
176 	  NULL
177 	},
178 	{
179 	  NGM_CISCO_COOKIE,
180 	  NGM_CISCO_GET_IPADDR,
181 	  "getipaddr",
182 	  NULL,
183 	  &ng_cisco_ipaddr_type
184 	},
185 	{ 0 }
186 };
187 
188 /* Node type descriptor */
189 static struct ng_type typestruct = {
190 	NG_ABI_VERSION,
191 	NG_IFACE_NODE_TYPE,
192 	NULL,
193 	ng_iface_constructor,
194 	ng_iface_rcvmsg,
195 	ng_iface_shutdown,
196 	ng_iface_newhook,
197 	NULL,
198 	NULL,
199 	ng_iface_rcvdata,
200 	ng_iface_disconnect,
201 	ng_iface_cmds
202 };
203 NETGRAPH_INIT(iface, &typestruct);
204 
205 /* We keep a bitmap indicating which unit numbers are free.
206    One means the unit number is free, zero means it's taken. */
207 static int	*ng_iface_units = NULL;
208 static int	ng_iface_units_len = 0;
209 static int	ng_units_in_use = 0;
210 
211 #define UNITS_BITSPERWORD	(sizeof(*ng_iface_units) * NBBY)
212 
213 /************************************************************************
214 			HELPER STUFF
215  ************************************************************************/
216 
217 /*
218  * Get the family descriptor from the family ID
219  */
220 static __inline__ iffam_p
221 get_iffam_from_af(sa_family_t family)
222 {
223 	iffam_p iffam;
224 	int k;
225 
226 	for (k = 0; k < NUM_FAMILIES; k++) {
227 		iffam = &gFamilies[k];
228 		if (iffam->family == family)
229 			return (iffam);
230 	}
231 	return (NULL);
232 }
233 
234 /*
235  * Get the family descriptor from the hook
236  */
237 static __inline__ iffam_p
238 get_iffam_from_hook(priv_p priv, hook_p hook)
239 {
240 	int k;
241 
242 	for (k = 0; k < NUM_FAMILIES; k++)
243 		if (priv->hooks[k] == hook)
244 			return (&gFamilies[k]);
245 	return (NULL);
246 }
247 
248 /*
249  * Get the hook from the iffam descriptor
250  */
251 
252 static __inline__ hook_p *
253 get_hook_from_iffam(priv_p priv, iffam_p iffam)
254 {
255 	return (&priv->hooks[iffam - gFamilies]);
256 }
257 
258 /*
259  * Get the iffam descriptor from the name
260  */
261 static __inline__ iffam_p
262 get_iffam_from_name(const char *name)
263 {
264 	iffam_p iffam;
265 	int k;
266 
267 	for (k = 0; k < NUM_FAMILIES; k++) {
268 		iffam = &gFamilies[k];
269 		if (!strcmp(iffam->hookname, name))
270 			return (iffam);
271 	}
272 	return (NULL);
273 }
274 
275 /*
276  * Find the first free unit number for a new interface.
277  * Increase the size of the unit bitmap as necessary.
278  */
279 static __inline__ int
280 ng_iface_get_unit(int *unit)
281 {
282 	int index, bit;
283 
284 	for (index = 0; index < ng_iface_units_len
285 	    && ng_iface_units[index] == 0; index++);
286 	if (index == ng_iface_units_len) {		/* extend array */
287 		int i, *newarray, newlen;
288 
289 		newlen = (2 * ng_iface_units_len) + 4;
290 		MALLOC(newarray, int *, newlen * sizeof(*ng_iface_units),
291 		    M_NETGRAPH_IFACE, M_NOWAIT);
292 		if (newarray == NULL)
293 			return (ENOMEM);
294 		bcopy(ng_iface_units, newarray,
295 		    ng_iface_units_len * sizeof(*ng_iface_units));
296 		for (i = ng_iface_units_len; i < newlen; i++)
297 			newarray[i] = ~0;
298 		if (ng_iface_units != NULL)
299 			FREE(ng_iface_units, M_NETGRAPH_IFACE);
300 		ng_iface_units = newarray;
301 		ng_iface_units_len = newlen;
302 	}
303 	bit = ffs(ng_iface_units[index]) - 1;
304 	KASSERT(bit >= 0 && bit <= UNITS_BITSPERWORD - 1,
305 	    ("%s: word=%d bit=%d", __func__, ng_iface_units[index], bit));
306 	ng_iface_units[index] &= ~(1 << bit);
307 	*unit = (index * UNITS_BITSPERWORD) + bit;
308 	ng_units_in_use++;
309 	return (0);
310 }
311 
312 /*
313  * Free a no longer needed unit number.
314  */
315 static __inline__ void
316 ng_iface_free_unit(int unit)
317 {
318 	int index, bit;
319 
320 	index = unit / UNITS_BITSPERWORD;
321 	bit = unit % UNITS_BITSPERWORD;
322 	KASSERT(index < ng_iface_units_len,
323 	    ("%s: unit=%d len=%d", __func__, unit, ng_iface_units_len));
324 	KASSERT((ng_iface_units[index] & (1 << bit)) == 0,
325 	    ("%s: unit=%d is free", __func__, unit));
326 	ng_iface_units[index] |= (1 << bit);
327 	/*
328 	 * XXX We could think about reducing the size of ng_iface_units[]
329 	 * XXX here if the last portion is all ones
330 	 * XXX At least free it if no more units.
331 	 * Needed if we are to eventually be able to unload.
332 	 */
333 	ng_units_in_use--;
334 	if (ng_units_in_use == 0) { /* XXX make SMP safe */
335 		FREE(ng_iface_units, M_NETGRAPH_IFACE);
336 		ng_iface_units_len = 0;
337 		ng_iface_units = NULL;
338 	}
339 }
340 
341 /************************************************************************
342 			INTERFACE STUFF
343  ************************************************************************/
344 
345 /*
346  * Process an ioctl for the virtual interface
347  */
348 static int
349 ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
350 {
351 	struct ifreq *const ifr = (struct ifreq *) data;
352 	int s, error = 0;
353 
354 #ifdef DEBUG
355 	ng_iface_print_ioctl(ifp, command, data);
356 #endif
357 	s = splimp();
358 	switch (command) {
359 
360 	/* These two are mostly handled at a higher layer */
361 	case SIOCSIFADDR:
362 		ifp->if_flags |= (IFF_UP | IFF_RUNNING);
363 		ifp->if_flags &= ~(IFF_OACTIVE);
364 		break;
365 	case SIOCGIFADDR:
366 		break;
367 
368 	/* Set flags */
369 	case SIOCSIFFLAGS:
370 		/*
371 		 * If the interface is marked up and stopped, then start it.
372 		 * If it is marked down and running, then stop it.
373 		 */
374 		if (ifr->ifr_flags & IFF_UP) {
375 			if (!(ifp->if_flags & IFF_RUNNING)) {
376 				ifp->if_flags &= ~(IFF_OACTIVE);
377 				ifp->if_flags |= IFF_RUNNING;
378 			}
379 		} else {
380 			if (ifp->if_flags & IFF_RUNNING)
381 				ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
382 		}
383 		break;
384 
385 	/* Set the interface MTU */
386 	case SIOCSIFMTU:
387 		if (ifr->ifr_mtu > NG_IFACE_MTU_MAX
388 		    || ifr->ifr_mtu < NG_IFACE_MTU_MIN)
389 			error = EINVAL;
390 		else
391 			ifp->if_mtu = ifr->ifr_mtu;
392 		break;
393 
394 	/* Stuff that's not supported */
395 	case SIOCADDMULTI:
396 	case SIOCDELMULTI:
397 		error = 0;
398 		break;
399 	case SIOCSIFPHYS:
400 		error = EOPNOTSUPP;
401 		break;
402 
403 	default:
404 		error = EINVAL;
405 		break;
406 	}
407 	(void) splx(s);
408 	return (error);
409 }
410 
411 /*
412  * This routine is called to deliver a packet out the interface.
413  * We simply look at the address family and relay the packet to
414  * the corresponding hook, if it exists and is connected.
415  */
416 
417 static int
418 ng_iface_output(struct ifnet *ifp, struct mbuf *m,
419 		struct sockaddr *dst, struct rtentry *rt0)
420 {
421 	const priv_p priv = (priv_p) ifp->if_softc;
422 	const iffam_p iffam = get_iffam_from_af(dst->sa_family);
423 	meta_p meta = NULL;
424 	int len, error = 0;
425 
426 	/* Check interface flags */
427 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
428 		m_freem(m);
429 		return (ENETDOWN);
430 	}
431 
432 	/* BPF writes need to be handled specially */
433 	if (dst->sa_family == AF_UNSPEC) {
434 		if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
435 			return (ENOBUFS);
436 		dst->sa_family = (sa_family_t)*mtod(m, int32_t *);
437 		m->m_data += 4;
438 		m->m_len -= 4;
439 		m->m_pkthdr.len -= 4;
440 	}
441 
442 	/* Berkeley packet filter */
443 	ng_iface_bpftap(ifp, m, dst->sa_family);
444 
445 	/* Check address family to determine hook (if known) */
446 	if (iffam == NULL) {
447 		m_freem(m);
448 		log(LOG_WARNING, "%s%d: can't handle af%d\n",
449 		       ifp->if_name, ifp->if_unit, (int)dst->sa_family);
450 		return (EAFNOSUPPORT);
451 	}
452 
453 	/* Copy length before the mbuf gets invalidated */
454 	len = m->m_pkthdr.len;
455 
456 	/* Send packet; if hook is not connected, mbuf will get freed. */
457 	NG_SEND_DATA(error, *get_hook_from_iffam(priv, iffam), m, meta);
458 
459 	/* Update stats */
460 	if (error == 0) {
461 		ifp->if_obytes += len;
462 		ifp->if_opackets++;
463 	}
464 	return (error);
465 }
466 
467 /*
468  * This routine should never be called
469  */
470 
471 static void
472 ng_iface_start(struct ifnet *ifp)
473 {
474 	if_printf(ifp, "%s called?", __func__);
475 }
476 
477 /*
478  * Flash a packet by the BPF (requires prepending 4 byte AF header)
479  * Note the phoney mbuf; this is OK because BPF treats it read-only.
480  */
481 static void
482 ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
483 {
484 	int32_t family4 = (int32_t)family;
485 	struct mbuf m0;
486 
487 	KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
488 	if (ifp->if_bpf != NULL) {
489 		bzero(&m0, sizeof(m0));
490 		m0.m_next = m;
491 		m0.m_len = sizeof(family4);
492 		m0.m_data = (char *)&family4;
493 		BPF_MTAP(ifp, &m0);
494 	}
495 }
496 
497 #ifdef DEBUG
498 /*
499  * Display an ioctl to the virtual interface
500  */
501 
502 static void
503 ng_iface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
504 {
505 	char   *str;
506 
507 	switch (command & IOC_DIRMASK) {
508 	case IOC_VOID:
509 		str = "IO";
510 		break;
511 	case IOC_OUT:
512 		str = "IOR";
513 		break;
514 	case IOC_IN:
515 		str = "IOW";
516 		break;
517 	case IOC_INOUT:
518 		str = "IORW";
519 		break;
520 	default:
521 		str = "IO??";
522 	}
523 	log(LOG_DEBUG, "%s%d: %s('%c', %d, char[%d])\n",
524 	       ifp->if_name, ifp->if_unit,
525 	       str,
526 	       IOCGROUP(command),
527 	       command & 0xff,
528 	       IOCPARM_LEN(command));
529 }
530 #endif /* DEBUG */
531 
532 /************************************************************************
533 			NETGRAPH NODE STUFF
534  ************************************************************************/
535 
536 /*
537  * Constructor for a node
538  */
539 static int
540 ng_iface_constructor(node_p node)
541 {
542 	char ifname[NG_IFACE_IFACE_NAME_MAX + 1];
543 	struct ifnet *ifp;
544 	priv_p priv;
545 	int error = 0;
546 
547 	/* Allocate node and interface private structures */
548 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
549 	if (priv == NULL)
550 		return (ENOMEM);
551 	MALLOC(ifp, struct ifnet *, sizeof(*ifp), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
552 	if (ifp == NULL) {
553 		FREE(priv, M_NETGRAPH_IFACE);
554 		return (ENOMEM);
555 	}
556 
557 	/* Link them together */
558 	ifp->if_softc = priv;
559 	priv->ifp = ifp;
560 
561 	/* Get an interface unit number */
562 	if ((error = ng_iface_get_unit(&priv->unit)) != 0) {
563 		FREE(ifp, M_NETGRAPH_IFACE);
564 		FREE(priv, M_NETGRAPH_IFACE);
565 		return (error);
566 	}
567 
568 	/* Link together node and private info */
569 	NG_NODE_SET_PRIVATE(node, priv);
570 	priv->node = node;
571 
572 	/* Initialize interface structure */
573 	ifp->if_name = NG_IFACE_IFACE_NAME;
574 	ifp->if_unit = priv->unit;
575 	ifp->if_output = ng_iface_output;
576 	ifp->if_start = ng_iface_start;
577 	ifp->if_ioctl = ng_iface_ioctl;
578 	ifp->if_watchdog = NULL;
579 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
580 	ifp->if_mtu = NG_IFACE_MTU_DEFAULT;
581 	ifp->if_flags = (IFF_SIMPLEX|IFF_POINTOPOINT|IFF_NOARP|IFF_MULTICAST);
582 	ifp->if_type = IFT_PROPVIRTUAL;		/* XXX */
583 	ifp->if_addrlen = 0;			/* XXX */
584 	ifp->if_hdrlen = 0;			/* XXX */
585 	ifp->if_baudrate = 64000;		/* XXX */
586 	TAILQ_INIT(&ifp->if_addrhead);
587 
588 	/* Give this node the same name as the interface (if possible) */
589 	bzero(ifname, sizeof(ifname));
590 	snprintf(ifname, sizeof(ifname), "%s%d", ifp->if_name, ifp->if_unit);
591 	if (ng_name_node(node, ifname) != 0)
592 		log(LOG_WARNING, "%s: can't acquire netgraph name\n", ifname);
593 
594 	/* Attach the interface */
595 	if_attach(ifp);
596 	bpfattach(ifp, DLT_NULL, sizeof(u_int));
597 
598 	/* Done */
599 	return (0);
600 }
601 
602 /*
603  * Give our ok for a hook to be added
604  */
605 static int
606 ng_iface_newhook(node_p node, hook_p hook, const char *name)
607 {
608 	const iffam_p iffam = get_iffam_from_name(name);
609 	hook_p *hookptr;
610 
611 	if (iffam == NULL)
612 		return (EPFNOSUPPORT);
613 	hookptr = get_hook_from_iffam(NG_NODE_PRIVATE(node), iffam);
614 	if (*hookptr != NULL)
615 		return (EISCONN);
616 	*hookptr = hook;
617 	return (0);
618 }
619 
620 /*
621  * Receive a control message
622  */
623 static int
624 ng_iface_rcvmsg(node_p node, item_p item, hook_p lasthook)
625 {
626 	const priv_p priv = NG_NODE_PRIVATE(node);
627 	struct ifnet *const ifp = priv->ifp;
628 	struct ng_mesg *resp = NULL;
629 	int error = 0;
630 	struct ng_mesg *msg;
631 
632 	NGI_GET_MSG(item, msg);
633 	switch (msg->header.typecookie) {
634 	case NGM_IFACE_COOKIE:
635 		switch (msg->header.cmd) {
636 		case NGM_IFACE_GET_IFNAME:
637 		    {
638 			struct ng_iface_ifname *arg;
639 
640 			NG_MKRESPONSE(resp, msg, sizeof(*arg), M_NOWAIT);
641 			if (resp == NULL) {
642 				error = ENOMEM;
643 				break;
644 			}
645 			arg = (struct ng_iface_ifname *)resp->data;
646 			snprintf(arg->ngif_name, sizeof(arg->ngif_name),
647 			    "%s%d", ifp->if_name, ifp->if_unit);
648 			break;
649 		    }
650 
651 		case NGM_IFACE_POINT2POINT:
652 		case NGM_IFACE_BROADCAST:
653 		    {
654 
655 			/* Deny request if interface is UP */
656 			if ((ifp->if_flags & IFF_UP) != 0)
657 				return (EBUSY);
658 
659 			/* Change flags */
660 			switch (msg->header.cmd) {
661 			case NGM_IFACE_POINT2POINT:
662 				ifp->if_flags |= IFF_POINTOPOINT;
663 				ifp->if_flags &= ~IFF_BROADCAST;
664 				break;
665 			case NGM_IFACE_BROADCAST:
666 				ifp->if_flags &= ~IFF_POINTOPOINT;
667 				ifp->if_flags |= IFF_BROADCAST;
668 				break;
669 			}
670 			break;
671 		    }
672 
673 		default:
674 			error = EINVAL;
675 			break;
676 		}
677 		break;
678 	case NGM_CISCO_COOKIE:
679 		switch (msg->header.cmd) {
680 		case NGM_CISCO_GET_IPADDR:	/* we understand this too */
681 		    {
682 			struct ifaddr *ifa;
683 
684 			/* Return the first configured IP address */
685 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
686 				struct ng_cisco_ipaddr *ips;
687 
688 				if (ifa->ifa_addr->sa_family != AF_INET)
689 					continue;
690 				NG_MKRESPONSE(resp, msg, sizeof(ips), M_NOWAIT);
691 				if (resp == NULL) {
692 					error = ENOMEM;
693 					break;
694 				}
695 				ips = (struct ng_cisco_ipaddr *)resp->data;
696 				ips->ipaddr = ((struct sockaddr_in *)
697 						ifa->ifa_addr)->sin_addr;
698 				ips->netmask = ((struct sockaddr_in *)
699 						ifa->ifa_netmask)->sin_addr;
700 				break;
701 			}
702 
703 			/* No IP addresses on this interface? */
704 			if (ifa == NULL)
705 				error = EADDRNOTAVAIL;
706 			break;
707 		    }
708 		default:
709 			error = EINVAL;
710 			break;
711 		}
712 		break;
713 	default:
714 		error = EINVAL;
715 		break;
716 	}
717 	NG_RESPOND_MSG(error, node, item, resp);
718 	NG_FREE_MSG(msg);
719 	return (error);
720 }
721 
722 /*
723  * Recive data from a hook. Pass the packet to the correct input routine.
724  */
725 static int
726 ng_iface_rcvdata(hook_p hook, item_p item)
727 {
728 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
729 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
730 	struct ifnet *const ifp = priv->ifp;
731 	struct mbuf *m;
732 
733 	NGI_GET_M(item, m);
734 	NG_FREE_ITEM(item);
735 	/* Sanity checks */
736 	KASSERT(iffam != NULL, ("%s: iffam", __func__));
737 	KASSERT(m->m_flags & M_PKTHDR, ("%s: not pkthdr", __func__));
738 	if (m == NULL)
739 		return (EINVAL);
740 	if ((ifp->if_flags & IFF_UP) == 0) {
741 		NG_FREE_M(m);
742 		return (ENETDOWN);
743 	}
744 
745 	/* Update interface stats */
746 	ifp->if_ipackets++;
747 	ifp->if_ibytes += m->m_pkthdr.len;
748 
749 	/* Note receiving interface */
750 	m->m_pkthdr.rcvif = ifp;
751 
752 	/* Berkeley packet filter */
753 	ng_iface_bpftap(ifp, m, iffam->family);
754 
755 	/* Send packet */
756 	return family_enqueue(iffam->family, m);
757 }
758 
759 /*
760  * Shutdown and remove the node and its associated interface.
761  */
762 static int
763 ng_iface_shutdown(node_p node)
764 {
765 	const priv_p priv = NG_NODE_PRIVATE(node);
766 
767 	bpfdetach(priv->ifp);
768 	if_detach(priv->ifp);
769 	FREE(priv->ifp, M_NETGRAPH_IFACE);
770 	priv->ifp = NULL;
771 	ng_iface_free_unit(priv->unit);
772 	FREE(priv, M_NETGRAPH_IFACE);
773 	NG_NODE_SET_PRIVATE(node, NULL);
774 	NG_NODE_UNREF(node);
775 	return (0);
776 }
777 
778 /*
779  * Hook disconnection. Note that we do *not* shutdown when all
780  * hooks have been disconnected.
781  */
782 static int
783 ng_iface_disconnect(hook_p hook)
784 {
785 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
786 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
787 
788 	if (iffam == NULL)
789 		panic(__func__);
790 	*get_hook_from_iffam(priv, iffam) = NULL;
791 	return (0);
792 }
793 
794