xref: /freebsd/sys/netgraph/ng_iface.c (revision 9162f64b58d01ec01481d60b6cdc06ffd8e8c7fc)
1 /*
2  * ng_iface.c
3  */
4 
5 /*-
6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
7  * All rights reserved.
8  *
9  * Subject to the following obligations and disclaimer of warranty, use and
10  * redistribution of this software, in source or object code forms, with or
11  * without modifications are expressly permitted by Whistle Communications;
12  * provided, however, that:
13  * 1. Any and all reproductions of the source or object code must include the
14  *    copyright notice above and the following disclaimer of warranties; and
15  * 2. No rights are granted, in any manner or form, to use Whistle
16  *    Communications, Inc. trademarks, including the mark "WHISTLE
17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18  *    such appears in the above copyright notice or in the software.
19  *
20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36  * OF SUCH DAMAGE.
37  *
38  * Author: Archie Cobbs <archie@freebsd.org>
39  *
40  * $FreeBSD$
41  * $Whistle: ng_iface.c,v 1.33 1999/11/01 09:24:51 julian Exp $
42  */
43 
44 /*
45  * This node is also a system networking interface. It has
46  * a hook for each protocol (IP, AppleTalk, IPX, etc). Packets
47  * are simply relayed between the interface and the hooks.
48  *
49  * Interfaces are named ng0, ng1, etc.  New nodes take the
50  * first available interface name.
51  *
52  * This node also includes Berkeley packet filter support.
53  */
54 
55 #include "opt_atalk.h"
56 #include "opt_inet.h"
57 #include "opt_inet6.h"
58 #include "opt_ipx.h"
59 
60 #include <sys/param.h>
61 #include <sys/systm.h>
62 #include <sys/errno.h>
63 #include <sys/kernel.h>
64 #include <sys/malloc.h>
65 #include <sys/mbuf.h>
66 #include <sys/errno.h>
67 #include <sys/random.h>
68 #include <sys/sockio.h>
69 #include <sys/socket.h>
70 #include <sys/syslog.h>
71 #include <sys/libkern.h>
72 #include <sys/vimage.h>
73 
74 #include <net/if.h>
75 #include <net/if_types.h>
76 #include <net/bpf.h>
77 #include <net/netisr.h>
78 
79 #include <netinet/in.h>
80 
81 #include <netgraph/ng_message.h>
82 #include <netgraph/netgraph.h>
83 #include <netgraph/ng_parse.h>
84 #include <netgraph/ng_iface.h>
85 #include <netgraph/ng_cisco.h>
86 
87 #ifdef NG_SEPARATE_MALLOC
88 MALLOC_DEFINE(M_NETGRAPH_IFACE, "netgraph_iface", "netgraph iface node ");
89 #else
90 #define M_NETGRAPH_IFACE M_NETGRAPH
91 #endif
92 
93 /* This struct describes one address family */
94 struct iffam {
95 	sa_family_t	family;		/* Address family */
96 	const char	*hookname;	/* Name for hook */
97 };
98 typedef const struct iffam *iffam_p;
99 
100 /* List of address families supported by our interface */
101 const static struct iffam gFamilies[] = {
102 	{ AF_INET,	NG_IFACE_HOOK_INET	},
103 	{ AF_INET6,	NG_IFACE_HOOK_INET6	},
104 	{ AF_APPLETALK,	NG_IFACE_HOOK_ATALK	},
105 	{ AF_IPX,	NG_IFACE_HOOK_IPX	},
106 	{ AF_ATM,	NG_IFACE_HOOK_ATM	},
107 	{ AF_NATM,	NG_IFACE_HOOK_NATM	},
108 };
109 #define NUM_FAMILIES		(sizeof(gFamilies) / sizeof(*gFamilies))
110 
111 /* Node private data */
112 struct ng_iface_private {
113 	struct	ifnet *ifp;		/* Our interface */
114 	int	unit;			/* Interface unit number */
115 	node_p	node;			/* Our netgraph node */
116 	hook_p	hooks[NUM_FAMILIES];	/* Hook for each address family */
117 };
118 typedef struct ng_iface_private *priv_p;
119 
120 /* Interface methods */
121 static void	ng_iface_start(struct ifnet *ifp);
122 static int	ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
123 static int	ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
124 			struct sockaddr *dst, struct rtentry *rt0);
125 static void	ng_iface_bpftap(struct ifnet *ifp,
126 			struct mbuf *m, sa_family_t family);
127 static int	ng_iface_send(struct ifnet *ifp, struct mbuf *m,
128 			sa_family_t sa);
129 #ifdef DEBUG
130 static void	ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
131 #endif
132 
133 /* Netgraph methods */
134 static int		ng_iface_mod_event(module_t, int, void *);
135 static ng_constructor_t	ng_iface_constructor;
136 static ng_rcvmsg_t	ng_iface_rcvmsg;
137 static ng_shutdown_t	ng_iface_shutdown;
138 static ng_newhook_t	ng_iface_newhook;
139 static ng_rcvdata_t	ng_iface_rcvdata;
140 static ng_disconnect_t	ng_iface_disconnect;
141 
142 /* Helper stuff */
143 static iffam_p	get_iffam_from_af(sa_family_t family);
144 static iffam_p	get_iffam_from_hook(priv_p priv, hook_p hook);
145 static iffam_p	get_iffam_from_name(const char *name);
146 static hook_p  *get_hook_from_iffam(priv_p priv, iffam_p iffam);
147 
148 /* Parse type for struct ng_cisco_ipaddr */
149 static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
150 	= NG_CISCO_IPADDR_TYPE_INFO;
151 static const struct ng_parse_type ng_cisco_ipaddr_type = {
152 	&ng_parse_struct_type,
153 	&ng_cisco_ipaddr_type_fields
154 };
155 
156 /* List of commands and how to convert arguments to/from ASCII */
157 static const struct ng_cmdlist ng_iface_cmds[] = {
158 	{
159 	  NGM_IFACE_COOKIE,
160 	  NGM_IFACE_GET_IFNAME,
161 	  "getifname",
162 	  NULL,
163 	  &ng_parse_string_type
164 	},
165 	{
166 	  NGM_IFACE_COOKIE,
167 	  NGM_IFACE_POINT2POINT,
168 	  "point2point",
169 	  NULL,
170 	  NULL
171 	},
172 	{
173 	  NGM_IFACE_COOKIE,
174 	  NGM_IFACE_BROADCAST,
175 	  "broadcast",
176 	  NULL,
177 	  NULL
178 	},
179 	{
180 	  NGM_CISCO_COOKIE,
181 	  NGM_CISCO_GET_IPADDR,
182 	  "getipaddr",
183 	  NULL,
184 	  &ng_cisco_ipaddr_type
185 	},
186 	{
187 	  NGM_IFACE_COOKIE,
188 	  NGM_IFACE_GET_IFINDEX,
189 	  "getifindex",
190 	  NULL,
191 	  &ng_parse_uint32_type
192 	},
193 	{ 0 }
194 };
195 
196 /* Node type descriptor */
197 static struct ng_type typestruct = {
198 	.version =	NG_ABI_VERSION,
199 	.name =		NG_IFACE_NODE_TYPE,
200 	.mod_event =	ng_iface_mod_event,
201 	.constructor =	ng_iface_constructor,
202 	.rcvmsg =	ng_iface_rcvmsg,
203 	.shutdown =	ng_iface_shutdown,
204 	.newhook =	ng_iface_newhook,
205 	.rcvdata =	ng_iface_rcvdata,
206 	.disconnect =	ng_iface_disconnect,
207 	.cmdlist =	ng_iface_cmds,
208 };
209 NETGRAPH_INIT(iface, &typestruct);
210 
211 #ifdef VIMAGE_GLOBALS
212 static struct unrhdr	*ng_iface_unit;
213 #endif
214 
215 /************************************************************************
216 			HELPER STUFF
217  ************************************************************************/
218 
219 /*
220  * Get the family descriptor from the family ID
221  */
222 static __inline iffam_p
223 get_iffam_from_af(sa_family_t family)
224 {
225 	iffam_p iffam;
226 	int k;
227 
228 	for (k = 0; k < NUM_FAMILIES; k++) {
229 		iffam = &gFamilies[k];
230 		if (iffam->family == family)
231 			return (iffam);
232 	}
233 	return (NULL);
234 }
235 
236 /*
237  * Get the family descriptor from the hook
238  */
239 static __inline iffam_p
240 get_iffam_from_hook(priv_p priv, hook_p hook)
241 {
242 	int k;
243 
244 	for (k = 0; k < NUM_FAMILIES; k++)
245 		if (priv->hooks[k] == hook)
246 			return (&gFamilies[k]);
247 	return (NULL);
248 }
249 
250 /*
251  * Get the hook from the iffam descriptor
252  */
253 
254 static __inline hook_p *
255 get_hook_from_iffam(priv_p priv, iffam_p iffam)
256 {
257 	return (&priv->hooks[iffam - gFamilies]);
258 }
259 
260 /*
261  * Get the iffam descriptor from the name
262  */
263 static __inline iffam_p
264 get_iffam_from_name(const char *name)
265 {
266 	iffam_p iffam;
267 	int k;
268 
269 	for (k = 0; k < NUM_FAMILIES; k++) {
270 		iffam = &gFamilies[k];
271 		if (!strcmp(iffam->hookname, name))
272 			return (iffam);
273 	}
274 	return (NULL);
275 }
276 
277 /************************************************************************
278 			INTERFACE STUFF
279  ************************************************************************/
280 
281 /*
282  * Process an ioctl for the virtual interface
283  */
284 static int
285 ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
286 {
287 	struct ifreq *const ifr = (struct ifreq *) data;
288 	int s, error = 0;
289 
290 #ifdef DEBUG
291 	ng_iface_print_ioctl(ifp, command, data);
292 #endif
293 	s = splimp();
294 	switch (command) {
295 
296 	/* These two are mostly handled at a higher layer */
297 	case SIOCSIFADDR:
298 		ifp->if_flags |= IFF_UP;
299 		ifp->if_drv_flags |= IFF_DRV_RUNNING;
300 		ifp->if_drv_flags &= ~(IFF_DRV_OACTIVE);
301 		break;
302 	case SIOCGIFADDR:
303 		break;
304 
305 	/* Set flags */
306 	case SIOCSIFFLAGS:
307 		/*
308 		 * If the interface is marked up and stopped, then start it.
309 		 * If it is marked down and running, then stop it.
310 		 */
311 		if (ifr->ifr_flags & IFF_UP) {
312 			if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
313 				ifp->if_drv_flags &= ~(IFF_DRV_OACTIVE);
314 				ifp->if_drv_flags |= IFF_DRV_RUNNING;
315 			}
316 		} else {
317 			if (ifp->if_drv_flags & IFF_DRV_RUNNING)
318 				ifp->if_drv_flags &= ~(IFF_DRV_RUNNING |
319 				    IFF_DRV_OACTIVE);
320 		}
321 		break;
322 
323 	/* Set the interface MTU */
324 	case SIOCSIFMTU:
325 		if (ifr->ifr_mtu > NG_IFACE_MTU_MAX
326 		    || ifr->ifr_mtu < NG_IFACE_MTU_MIN)
327 			error = EINVAL;
328 		else
329 			ifp->if_mtu = ifr->ifr_mtu;
330 		break;
331 
332 	/* Stuff that's not supported */
333 	case SIOCADDMULTI:
334 	case SIOCDELMULTI:
335 		error = 0;
336 		break;
337 	case SIOCSIFPHYS:
338 		error = EOPNOTSUPP;
339 		break;
340 
341 	default:
342 		error = EINVAL;
343 		break;
344 	}
345 	(void) splx(s);
346 	return (error);
347 }
348 
349 /*
350  * This routine is called to deliver a packet out the interface.
351  * We simply look at the address family and relay the packet to
352  * the corresponding hook, if it exists and is connected.
353  */
354 
355 static int
356 ng_iface_output(struct ifnet *ifp, struct mbuf *m,
357 		struct sockaddr *dst, struct rtentry *rt0)
358 {
359 	uint32_t af;
360 	int error;
361 
362 	/* Check interface flags */
363 	if (!((ifp->if_flags & IFF_UP) &&
364 	    (ifp->if_drv_flags & IFF_DRV_RUNNING))) {
365 		m_freem(m);
366 		return (ENETDOWN);
367 	}
368 
369 	/* BPF writes need to be handled specially. */
370 	if (dst->sa_family == AF_UNSPEC) {
371 		bcopy(dst->sa_data, &af, sizeof(af));
372 		dst->sa_family = af;
373 	}
374 
375 	/* Berkeley packet filter */
376 	ng_iface_bpftap(ifp, m, dst->sa_family);
377 
378 	if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
379 		M_PREPEND(m, sizeof(sa_family_t), M_DONTWAIT);
380 		if (m == NULL) {
381 			IFQ_LOCK(&ifp->if_snd);
382 			IFQ_INC_DROPS(&ifp->if_snd);
383 			IFQ_UNLOCK(&ifp->if_snd);
384 			ifp->if_oerrors++;
385 			return (ENOBUFS);
386 		}
387 		*(sa_family_t *)m->m_data = dst->sa_family;
388 		error = (ifp->if_transmit)(ifp, m);
389 	} else
390 		error = ng_iface_send(ifp, m, dst->sa_family);
391 
392 	return (error);
393 }
394 
395 /*
396  * Start method is used only when ALTQ is enabled.
397  */
398 static void
399 ng_iface_start(struct ifnet *ifp)
400 {
401 	struct mbuf *m;
402 	sa_family_t sa;
403 
404 	KASSERT(ALTQ_IS_ENABLED(&ifp->if_snd), ("%s without ALTQ", __func__));
405 
406 	for(;;) {
407 		IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
408 		if (m == NULL)
409 			break;
410 		sa = *mtod(m, sa_family_t *);
411 		m_adj(m, sizeof(sa_family_t));
412 		ng_iface_send(ifp, m, sa);
413 	}
414 }
415 
416 /*
417  * Flash a packet by the BPF (requires prepending 4 byte AF header)
418  * Note the phoney mbuf; this is OK because BPF treats it read-only.
419  */
420 static void
421 ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
422 {
423 	KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
424 	if (bpf_peers_present(ifp->if_bpf)) {
425 		int32_t family4 = (int32_t)family;
426 		bpf_mtap2(ifp->if_bpf, &family4, sizeof(family4), m);
427 	}
428 }
429 
430 /*
431  * This routine does actual delivery of the packet into the
432  * netgraph(4). It is called from ng_iface_start() and
433  * ng_iface_output().
434  */
435 static int
436 ng_iface_send(struct ifnet *ifp, struct mbuf *m, sa_family_t sa)
437 {
438 	const priv_p priv = (priv_p) ifp->if_softc;
439 	const iffam_p iffam = get_iffam_from_af(sa);
440 	int error;
441 	int len;
442 
443 	/* Check address family to determine hook (if known) */
444 	if (iffam == NULL) {
445 		m_freem(m);
446 		log(LOG_WARNING, "%s: can't handle af%d\n", ifp->if_xname, sa);
447 		return (EAFNOSUPPORT);
448 	}
449 
450 	/* Copy length before the mbuf gets invalidated. */
451 	len = m->m_pkthdr.len;
452 
453 	/* Send packet. If hook is not connected,
454 	   mbuf will get freed. */
455 	NG_SEND_DATA_ONLY(error, *get_hook_from_iffam(priv, iffam), m);
456 
457 	/* Update stats. */
458 	if (error == 0) {
459 		ifp->if_obytes += len;
460 		ifp->if_opackets++;
461 	}
462 
463 	return (error);
464 }
465 
466 #ifdef DEBUG
467 /*
468  * Display an ioctl to the virtual interface
469  */
470 
471 static void
472 ng_iface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
473 {
474 	char   *str;
475 
476 	switch (command & IOC_DIRMASK) {
477 	case IOC_VOID:
478 		str = "IO";
479 		break;
480 	case IOC_OUT:
481 		str = "IOR";
482 		break;
483 	case IOC_IN:
484 		str = "IOW";
485 		break;
486 	case IOC_INOUT:
487 		str = "IORW";
488 		break;
489 	default:
490 		str = "IO??";
491 	}
492 	log(LOG_DEBUG, "%s: %s('%c', %d, char[%d])\n",
493 	       ifp->if_xname,
494 	       str,
495 	       IOCGROUP(command),
496 	       command & 0xff,
497 	       IOCPARM_LEN(command));
498 }
499 #endif /* DEBUG */
500 
501 /************************************************************************
502 			NETGRAPH NODE STUFF
503  ************************************************************************/
504 
505 /*
506  * Constructor for a node
507  */
508 static int
509 ng_iface_constructor(node_p node)
510 {
511 	INIT_VNET_NETGRAPH(curvnet);
512 	struct ifnet *ifp;
513 	priv_p priv;
514 
515 	/* Allocate node and interface private structures */
516 	priv = malloc(sizeof(*priv), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
517 	if (priv == NULL)
518 		return (ENOMEM);
519 	ifp = if_alloc(IFT_PROPVIRTUAL);
520 	if (ifp == NULL) {
521 		free(priv, M_NETGRAPH_IFACE);
522 		return (ENOMEM);
523 	}
524 
525 	/* Link them together */
526 	ifp->if_softc = priv;
527 	priv->ifp = ifp;
528 
529 	/* Get an interface unit number */
530 	priv->unit = alloc_unr(V_ng_iface_unit);
531 
532 	/* Link together node and private info */
533 	NG_NODE_SET_PRIVATE(node, priv);
534 	priv->node = node;
535 
536 	/* Initialize interface structure */
537 	if_initname(ifp, NG_IFACE_IFACE_NAME, priv->unit);
538 	ifp->if_output = ng_iface_output;
539 	ifp->if_start = ng_iface_start;
540 	ifp->if_ioctl = ng_iface_ioctl;
541 	ifp->if_watchdog = NULL;
542 	ifp->if_mtu = NG_IFACE_MTU_DEFAULT;
543 	ifp->if_flags = (IFF_SIMPLEX|IFF_POINTOPOINT|IFF_NOARP|IFF_MULTICAST);
544 	ifp->if_type = IFT_PROPVIRTUAL;		/* XXX */
545 	ifp->if_addrlen = 0;			/* XXX */
546 	ifp->if_hdrlen = 0;			/* XXX */
547 	ifp->if_baudrate = 64000;		/* XXX */
548 	IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN);
549 	ifp->if_snd.ifq_drv_maxlen = IFQ_MAXLEN;
550 	IFQ_SET_READY(&ifp->if_snd);
551 
552 	/* Give this node the same name as the interface (if possible) */
553 	if (ng_name_node(node, ifp->if_xname) != 0)
554 		log(LOG_WARNING, "%s: can't acquire netgraph name\n",
555 		    ifp->if_xname);
556 
557 	/* Attach the interface */
558 	if_attach(ifp);
559 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
560 
561 	/* Done */
562 	return (0);
563 }
564 
565 /*
566  * Give our ok for a hook to be added
567  */
568 static int
569 ng_iface_newhook(node_p node, hook_p hook, const char *name)
570 {
571 	const iffam_p iffam = get_iffam_from_name(name);
572 	hook_p *hookptr;
573 
574 	if (iffam == NULL)
575 		return (EPFNOSUPPORT);
576 	hookptr = get_hook_from_iffam(NG_NODE_PRIVATE(node), iffam);
577 	if (*hookptr != NULL)
578 		return (EISCONN);
579 	*hookptr = hook;
580 	NG_HOOK_HI_STACK(hook);
581 	return (0);
582 }
583 
584 /*
585  * Receive a control message
586  */
587 static int
588 ng_iface_rcvmsg(node_p node, item_p item, hook_p lasthook)
589 {
590 	const priv_p priv = NG_NODE_PRIVATE(node);
591 	struct ifnet *const ifp = priv->ifp;
592 	struct ng_mesg *resp = NULL;
593 	int error = 0;
594 	struct ng_mesg *msg;
595 
596 	NGI_GET_MSG(item, msg);
597 	switch (msg->header.typecookie) {
598 	case NGM_IFACE_COOKIE:
599 		switch (msg->header.cmd) {
600 		case NGM_IFACE_GET_IFNAME:
601 			NG_MKRESPONSE(resp, msg, IFNAMSIZ, M_NOWAIT);
602 			if (resp == NULL) {
603 				error = ENOMEM;
604 				break;
605 			}
606 			strlcpy(resp->data, ifp->if_xname, IFNAMSIZ);
607 			break;
608 
609 		case NGM_IFACE_POINT2POINT:
610 		case NGM_IFACE_BROADCAST:
611 		    {
612 
613 			/* Deny request if interface is UP */
614 			if ((ifp->if_flags & IFF_UP) != 0)
615 				return (EBUSY);
616 
617 			/* Change flags */
618 			switch (msg->header.cmd) {
619 			case NGM_IFACE_POINT2POINT:
620 				ifp->if_flags |= IFF_POINTOPOINT;
621 				ifp->if_flags &= ~IFF_BROADCAST;
622 				break;
623 			case NGM_IFACE_BROADCAST:
624 				ifp->if_flags &= ~IFF_POINTOPOINT;
625 				ifp->if_flags |= IFF_BROADCAST;
626 				break;
627 			}
628 			break;
629 		    }
630 
631 		case NGM_IFACE_GET_IFINDEX:
632 			NG_MKRESPONSE(resp, msg, sizeof(uint32_t), M_NOWAIT);
633 			if (resp == NULL) {
634 				error = ENOMEM;
635 				break;
636 			}
637 			*((uint32_t *)resp->data) = priv->ifp->if_index;
638 			break;
639 
640 		default:
641 			error = EINVAL;
642 			break;
643 		}
644 		break;
645 	case NGM_CISCO_COOKIE:
646 		switch (msg->header.cmd) {
647 		case NGM_CISCO_GET_IPADDR:	/* we understand this too */
648 		    {
649 			struct ifaddr *ifa;
650 
651 			/* Return the first configured IP address */
652 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
653 				struct ng_cisco_ipaddr *ips;
654 
655 				if (ifa->ifa_addr->sa_family != AF_INET)
656 					continue;
657 				NG_MKRESPONSE(resp, msg, sizeof(ips), M_NOWAIT);
658 				if (resp == NULL) {
659 					error = ENOMEM;
660 					break;
661 				}
662 				ips = (struct ng_cisco_ipaddr *)resp->data;
663 				ips->ipaddr = ((struct sockaddr_in *)
664 						ifa->ifa_addr)->sin_addr;
665 				ips->netmask = ((struct sockaddr_in *)
666 						ifa->ifa_netmask)->sin_addr;
667 				break;
668 			}
669 
670 			/* No IP addresses on this interface? */
671 			if (ifa == NULL)
672 				error = EADDRNOTAVAIL;
673 			break;
674 		    }
675 		default:
676 			error = EINVAL;
677 			break;
678 		}
679 		break;
680 	case NGM_FLOW_COOKIE:
681 		switch (msg->header.cmd) {
682 		case NGM_LINK_IS_UP:
683 			ifp->if_drv_flags |= IFF_DRV_RUNNING;
684 			break;
685 		case NGM_LINK_IS_DOWN:
686 			ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
687 			break;
688 		default:
689 			break;
690 		}
691 		break;
692 	default:
693 		error = EINVAL;
694 		break;
695 	}
696 	NG_RESPOND_MSG(error, node, item, resp);
697 	NG_FREE_MSG(msg);
698 	return (error);
699 }
700 
701 /*
702  * Recive data from a hook. Pass the packet to the correct input routine.
703  */
704 static int
705 ng_iface_rcvdata(hook_p hook, item_p item)
706 {
707 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
708 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
709 	struct ifnet *const ifp = priv->ifp;
710 	struct mbuf *m;
711 	int isr;
712 
713 	NGI_GET_M(item, m);
714 	NG_FREE_ITEM(item);
715 	/* Sanity checks */
716 	KASSERT(iffam != NULL, ("%s: iffam", __func__));
717 	M_ASSERTPKTHDR(m);
718 	if ((ifp->if_flags & IFF_UP) == 0) {
719 		NG_FREE_M(m);
720 		return (ENETDOWN);
721 	}
722 
723 	/* Update interface stats */
724 	ifp->if_ipackets++;
725 	ifp->if_ibytes += m->m_pkthdr.len;
726 
727 	/* Note receiving interface */
728 	m->m_pkthdr.rcvif = ifp;
729 
730 	/* Berkeley packet filter */
731 	ng_iface_bpftap(ifp, m, iffam->family);
732 
733 	/* Send packet */
734 	switch (iffam->family) {
735 #ifdef INET
736 	case AF_INET:
737 		isr = NETISR_IP;
738 		break;
739 #endif
740 #ifdef INET6
741 	case AF_INET6:
742 		isr = NETISR_IPV6;
743 		break;
744 #endif
745 #ifdef IPX
746 	case AF_IPX:
747 		isr = NETISR_IPX;
748 		break;
749 #endif
750 #ifdef NETATALK
751 	case AF_APPLETALK:
752 		isr = NETISR_ATALK2;
753 		break;
754 #endif
755 	default:
756 		m_freem(m);
757 		return (EAFNOSUPPORT);
758 	}
759 	/* First chunk of an mbuf contains good junk */
760 	if (harvest.point_to_point)
761 		random_harvest(m, 16, 3, 0, RANDOM_NET);
762 	netisr_dispatch(isr, m);
763 	return (0);
764 }
765 
766 /*
767  * Shutdown and remove the node and its associated interface.
768  */
769 static int
770 ng_iface_shutdown(node_p node)
771 {
772 	INIT_VNET_NETGRAPH(curvnet);
773 	const priv_p priv = NG_NODE_PRIVATE(node);
774 
775 	/*
776 	 * The ifnet may be in a different vnet than the netgraph node,
777 	 * hence we have to change the current vnet context here.
778 	 */
779 	CURVNET_SET_QUIET(priv->ifp->if_vnet);
780 	bpfdetach(priv->ifp);
781 	if_detach(priv->ifp);
782 	if_free(priv->ifp);
783 	CURVNET_RESTORE();
784 	priv->ifp = NULL;
785 	free_unr(V_ng_iface_unit, priv->unit);
786 	free(priv, M_NETGRAPH_IFACE);
787 	NG_NODE_SET_PRIVATE(node, NULL);
788 	NG_NODE_UNREF(node);
789 	return (0);
790 }
791 
792 /*
793  * Hook disconnection. Note that we do *not* shutdown when all
794  * hooks have been disconnected.
795  */
796 static int
797 ng_iface_disconnect(hook_p hook)
798 {
799 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
800 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
801 
802 	if (iffam == NULL)
803 		panic(__func__);
804 	*get_hook_from_iffam(priv, iffam) = NULL;
805 	return (0);
806 }
807 
808 /*
809  * Handle loading and unloading for this node type.
810  */
811 static int
812 ng_iface_mod_event(module_t mod, int event, void *data)
813 {
814 	int error = 0;
815 
816 	switch (event) {
817 	case MOD_LOAD:
818 		V_ng_iface_unit = new_unrhdr(0, 0xffff, NULL);
819 		break;
820 	case MOD_UNLOAD:
821 		delete_unrhdr(V_ng_iface_unit);
822 		break;
823 	default:
824 		error = EOPNOTSUPP;
825 		break;
826 	}
827 	return (error);
828 }
829