xref: /freebsd/sys/netgraph/ng_iface.c (revision 1164db57e40de8efae073eba01ba85bb26ae5a8d)
1 /*
2  * ng_iface.c
3  *
4  * Copyright (c) 1996-1999 Whistle Communications, Inc.
5  * All rights reserved.
6  *
7  * Subject to the following obligations and disclaimer of warranty, use and
8  * redistribution of this software, in source or object code forms, with or
9  * without modifications are expressly permitted by Whistle Communications;
10  * provided, however, that:
11  * 1. Any and all reproductions of the source or object code must include the
12  *    copyright notice above and the following disclaimer of warranties; and
13  * 2. No rights are granted, in any manner or form, to use Whistle
14  *    Communications, Inc. trademarks, including the mark "WHISTLE
15  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
16  *    such appears in the above copyright notice or in the software.
17  *
18  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
19  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
20  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
21  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
22  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
23  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
24  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
25  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
26  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
27  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
28  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
29  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
30  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
34  * OF SUCH DAMAGE.
35  *
36  * Author: Archie Cobbs <archie@freebsd.org>
37  *
38  * $FreeBSD$
39  * $Whistle: ng_iface.c,v 1.33 1999/11/01 09:24:51 julian Exp $
40  */
41 
42 /*
43  * This node is also a system networking interface. It has
44  * a hook for each protocol (IP, AppleTalk, IPX, etc). Packets
45  * are simply relayed between the interface and the hooks.
46  *
47  * Interfaces are named ng0, ng1, etc.  New nodes take the
48  * first available interface name.
49  *
50  * This node also includes Berkeley packet filter support.
51  */
52 
53 #include "opt_atalk.h"
54 #include "opt_inet.h"
55 #include "opt_inet6.h"
56 #include "opt_ipx.h"
57 
58 #include <sys/param.h>
59 #include <sys/systm.h>
60 #include <sys/errno.h>
61 #include <sys/kernel.h>
62 #include <sys/malloc.h>
63 #include <sys/mbuf.h>
64 #include <sys/errno.h>
65 #include <sys/random.h>
66 #include <sys/sockio.h>
67 #include <sys/socket.h>
68 #include <sys/syslog.h>
69 #include <sys/libkern.h>
70 
71 #include <net/if.h>
72 #include <net/if_types.h>
73 #include <net/bpf.h>
74 #include <net/netisr.h>
75 
76 #include <netinet/in.h>
77 
78 #include <netgraph/ng_message.h>
79 #include <netgraph/netgraph.h>
80 #include <netgraph/ng_parse.h>
81 #include <netgraph/ng_iface.h>
82 #include <netgraph/ng_cisco.h>
83 
84 #ifdef NG_SEPARATE_MALLOC
85 MALLOC_DEFINE(M_NETGRAPH_IFACE, "netgraph_iface", "netgraph iface node ");
86 #else
87 #define M_NETGRAPH_IFACE M_NETGRAPH
88 #endif
89 
90 /* This struct describes one address family */
91 struct iffam {
92 	sa_family_t	family;		/* Address family */
93 	const char	*hookname;	/* Name for hook */
94 };
95 typedef const struct iffam *iffam_p;
96 
97 /* List of address families supported by our interface */
98 const static struct iffam gFamilies[] = {
99 	{ AF_INET,	NG_IFACE_HOOK_INET	},
100 	{ AF_INET6,	NG_IFACE_HOOK_INET6	},
101 	{ AF_APPLETALK,	NG_IFACE_HOOK_ATALK	},
102 	{ AF_IPX,	NG_IFACE_HOOK_IPX	},
103 	{ AF_ATM,	NG_IFACE_HOOK_ATM	},
104 	{ AF_NATM,	NG_IFACE_HOOK_NATM	},
105 };
106 #define NUM_FAMILIES		(sizeof(gFamilies) / sizeof(*gFamilies))
107 
108 /* Node private data */
109 struct ng_iface_private {
110 	struct	ifnet *ifp;		/* Our interface */
111 	int	unit;			/* Interface unit number */
112 	node_p	node;			/* Our netgraph node */
113 	hook_p	hooks[NUM_FAMILIES];	/* Hook for each address family */
114 };
115 typedef struct ng_iface_private *priv_p;
116 
117 /* Interface methods */
118 static void	ng_iface_start(struct ifnet *ifp);
119 static int	ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
120 static int	ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
121 			struct sockaddr *dst, struct rtentry *rt0);
122 static void	ng_iface_bpftap(struct ifnet *ifp,
123 			struct mbuf *m, sa_family_t family);
124 #ifdef DEBUG
125 static void	ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
126 #endif
127 
128 /* Netgraph methods */
129 static ng_constructor_t	ng_iface_constructor;
130 static ng_rcvmsg_t	ng_iface_rcvmsg;
131 static ng_shutdown_t	ng_iface_shutdown;
132 static ng_newhook_t	ng_iface_newhook;
133 static ng_rcvdata_t	ng_iface_rcvdata;
134 static ng_disconnect_t	ng_iface_disconnect;
135 
136 /* Helper stuff */
137 static iffam_p	get_iffam_from_af(sa_family_t family);
138 static iffam_p	get_iffam_from_hook(priv_p priv, hook_p hook);
139 static iffam_p	get_iffam_from_name(const char *name);
140 static hook_p  *get_hook_from_iffam(priv_p priv, iffam_p iffam);
141 
142 /* Parse type for struct ng_iface_ifname */
143 static const struct ng_parse_fixedstring_info ng_iface_ifname_info = {
144 	NG_IFACE_IFACE_NAME_MAX + 1
145 };
146 static const struct ng_parse_type ng_iface_ifname_type = {
147 	&ng_parse_fixedstring_type,
148 	&ng_iface_ifname_info
149 };
150 
151 /* Parse type for struct ng_cisco_ipaddr */
152 static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
153 	= NG_CISCO_IPADDR_TYPE_INFO;
154 static const struct ng_parse_type ng_cisco_ipaddr_type = {
155 	&ng_parse_struct_type,
156 	&ng_cisco_ipaddr_type_fields
157 };
158 
159 /* List of commands and how to convert arguments to/from ASCII */
160 static const struct ng_cmdlist ng_iface_cmds[] = {
161 	{
162 	  NGM_IFACE_COOKIE,
163 	  NGM_IFACE_GET_IFNAME,
164 	  "getifname",
165 	  NULL,
166 	  &ng_iface_ifname_type
167 	},
168 	{
169 	  NGM_IFACE_COOKIE,
170 	  NGM_IFACE_POINT2POINT,
171 	  "point2point",
172 	  NULL,
173 	  NULL
174 	},
175 	{
176 	  NGM_IFACE_COOKIE,
177 	  NGM_IFACE_BROADCAST,
178 	  "broadcast",
179 	  NULL,
180 	  NULL
181 	},
182 	{
183 	  NGM_CISCO_COOKIE,
184 	  NGM_CISCO_GET_IPADDR,
185 	  "getipaddr",
186 	  NULL,
187 	  &ng_cisco_ipaddr_type
188 	},
189 	{
190 	  NGM_IFACE_COOKIE,
191 	  NGM_IFACE_GET_IFINDEX,
192 	  "getifindex",
193 	  NULL,
194 	  &ng_parse_uint32_type
195 	},
196 	{ 0 }
197 };
198 
199 /* Node type descriptor */
200 static struct ng_type typestruct = {
201 	NG_ABI_VERSION,
202 	NG_IFACE_NODE_TYPE,
203 	NULL,
204 	ng_iface_constructor,
205 	ng_iface_rcvmsg,
206 	ng_iface_shutdown,
207 	ng_iface_newhook,
208 	NULL,
209 	NULL,
210 	ng_iface_rcvdata,
211 	ng_iface_disconnect,
212 	ng_iface_cmds
213 };
214 NETGRAPH_INIT(iface, &typestruct);
215 
216 /* We keep a bitmap indicating which unit numbers are free.
217    One means the unit number is free, zero means it's taken. */
218 static int	*ng_iface_units = NULL;
219 static int	ng_iface_units_len = 0;
220 static int	ng_units_in_use = 0;
221 
222 #define UNITS_BITSPERWORD	(sizeof(*ng_iface_units) * NBBY)
223 
224 /************************************************************************
225 			HELPER STUFF
226  ************************************************************************/
227 
228 /*
229  * Get the family descriptor from the family ID
230  */
231 static __inline__ iffam_p
232 get_iffam_from_af(sa_family_t family)
233 {
234 	iffam_p iffam;
235 	int k;
236 
237 	for (k = 0; k < NUM_FAMILIES; k++) {
238 		iffam = &gFamilies[k];
239 		if (iffam->family == family)
240 			return (iffam);
241 	}
242 	return (NULL);
243 }
244 
245 /*
246  * Get the family descriptor from the hook
247  */
248 static __inline__ iffam_p
249 get_iffam_from_hook(priv_p priv, hook_p hook)
250 {
251 	int k;
252 
253 	for (k = 0; k < NUM_FAMILIES; k++)
254 		if (priv->hooks[k] == hook)
255 			return (&gFamilies[k]);
256 	return (NULL);
257 }
258 
259 /*
260  * Get the hook from the iffam descriptor
261  */
262 
263 static __inline__ hook_p *
264 get_hook_from_iffam(priv_p priv, iffam_p iffam)
265 {
266 	return (&priv->hooks[iffam - gFamilies]);
267 }
268 
269 /*
270  * Get the iffam descriptor from the name
271  */
272 static __inline__ iffam_p
273 get_iffam_from_name(const char *name)
274 {
275 	iffam_p iffam;
276 	int k;
277 
278 	for (k = 0; k < NUM_FAMILIES; k++) {
279 		iffam = &gFamilies[k];
280 		if (!strcmp(iffam->hookname, name))
281 			return (iffam);
282 	}
283 	return (NULL);
284 }
285 
286 /*
287  * Find the first free unit number for a new interface.
288  * Increase the size of the unit bitmap as necessary.
289  */
290 static __inline__ int
291 ng_iface_get_unit(int *unit)
292 {
293 	int index, bit;
294 
295 	for (index = 0; index < ng_iface_units_len
296 	    && ng_iface_units[index] == 0; index++);
297 	if (index == ng_iface_units_len) {		/* extend array */
298 		int i, *newarray, newlen;
299 
300 		newlen = (2 * ng_iface_units_len) + 4;
301 		MALLOC(newarray, int *, newlen * sizeof(*ng_iface_units),
302 		    M_NETGRAPH_IFACE, M_NOWAIT);
303 		if (newarray == NULL)
304 			return (ENOMEM);
305 		bcopy(ng_iface_units, newarray,
306 		    ng_iface_units_len * sizeof(*ng_iface_units));
307 		for (i = ng_iface_units_len; i < newlen; i++)
308 			newarray[i] = ~0;
309 		if (ng_iface_units != NULL)
310 			FREE(ng_iface_units, M_NETGRAPH_IFACE);
311 		ng_iface_units = newarray;
312 		ng_iface_units_len = newlen;
313 	}
314 	bit = ffs(ng_iface_units[index]) - 1;
315 	KASSERT(bit >= 0 && bit <= UNITS_BITSPERWORD - 1,
316 	    ("%s: word=%d bit=%d", __func__, ng_iface_units[index], bit));
317 	ng_iface_units[index] &= ~(1 << bit);
318 	*unit = (index * UNITS_BITSPERWORD) + bit;
319 	ng_units_in_use++;
320 	return (0);
321 }
322 
323 /*
324  * Free a no longer needed unit number.
325  */
326 static __inline__ void
327 ng_iface_free_unit(int unit)
328 {
329 	int index, bit;
330 
331 	index = unit / UNITS_BITSPERWORD;
332 	bit = unit % UNITS_BITSPERWORD;
333 	KASSERT(index < ng_iface_units_len,
334 	    ("%s: unit=%d len=%d", __func__, unit, ng_iface_units_len));
335 	KASSERT((ng_iface_units[index] & (1 << bit)) == 0,
336 	    ("%s: unit=%d is free", __func__, unit));
337 	ng_iface_units[index] |= (1 << bit);
338 	/*
339 	 * XXX We could think about reducing the size of ng_iface_units[]
340 	 * XXX here if the last portion is all ones
341 	 * XXX At least free it if no more units.
342 	 * Needed if we are to eventually be able to unload.
343 	 */
344 	ng_units_in_use--;
345 	if (ng_units_in_use == 0) { /* XXX make SMP safe */
346 		FREE(ng_iface_units, M_NETGRAPH_IFACE);
347 		ng_iface_units_len = 0;
348 		ng_iface_units = NULL;
349 	}
350 }
351 
352 /************************************************************************
353 			INTERFACE STUFF
354  ************************************************************************/
355 
356 /*
357  * Process an ioctl for the virtual interface
358  */
359 static int
360 ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
361 {
362 	struct ifreq *const ifr = (struct ifreq *) data;
363 	int s, error = 0;
364 
365 #ifdef DEBUG
366 	ng_iface_print_ioctl(ifp, command, data);
367 #endif
368 	s = splimp();
369 	switch (command) {
370 
371 	/* These two are mostly handled at a higher layer */
372 	case SIOCSIFADDR:
373 		ifp->if_flags |= (IFF_UP | IFF_RUNNING);
374 		ifp->if_flags &= ~(IFF_OACTIVE);
375 		break;
376 	case SIOCGIFADDR:
377 		break;
378 
379 	/* Set flags */
380 	case SIOCSIFFLAGS:
381 		/*
382 		 * If the interface is marked up and stopped, then start it.
383 		 * If it is marked down and running, then stop it.
384 		 */
385 		if (ifr->ifr_flags & IFF_UP) {
386 			if (!(ifp->if_flags & IFF_RUNNING)) {
387 				ifp->if_flags &= ~(IFF_OACTIVE);
388 				ifp->if_flags |= IFF_RUNNING;
389 			}
390 		} else {
391 			if (ifp->if_flags & IFF_RUNNING)
392 				ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
393 		}
394 		break;
395 
396 	/* Set the interface MTU */
397 	case SIOCSIFMTU:
398 		if (ifr->ifr_mtu > NG_IFACE_MTU_MAX
399 		    || ifr->ifr_mtu < NG_IFACE_MTU_MIN)
400 			error = EINVAL;
401 		else
402 			ifp->if_mtu = ifr->ifr_mtu;
403 		break;
404 
405 	/* Stuff that's not supported */
406 	case SIOCADDMULTI:
407 	case SIOCDELMULTI:
408 		error = 0;
409 		break;
410 	case SIOCSIFPHYS:
411 		error = EOPNOTSUPP;
412 		break;
413 
414 	default:
415 		error = EINVAL;
416 		break;
417 	}
418 	(void) splx(s);
419 	return (error);
420 }
421 
422 /*
423  * This routine is called to deliver a packet out the interface.
424  * We simply look at the address family and relay the packet to
425  * the corresponding hook, if it exists and is connected.
426  */
427 
428 static int
429 ng_iface_output(struct ifnet *ifp, struct mbuf *m,
430 		struct sockaddr *dst, struct rtentry *rt0)
431 {
432 	const priv_p priv = (priv_p) ifp->if_softc;
433 	const iffam_p iffam = get_iffam_from_af(dst->sa_family);
434 	meta_p meta = NULL;
435 	int len, error = 0;
436 
437 	/* Check interface flags */
438 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
439 		m_freem(m);
440 		return (ENETDOWN);
441 	}
442 
443 	/* BPF writes need to be handled specially */
444 	if (dst->sa_family == AF_UNSPEC) {
445 		if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
446 			return (ENOBUFS);
447 		dst->sa_family = (sa_family_t)*mtod(m, int32_t *);
448 		m->m_data += 4;
449 		m->m_len -= 4;
450 		m->m_pkthdr.len -= 4;
451 	}
452 
453 	/* Berkeley packet filter */
454 	ng_iface_bpftap(ifp, m, dst->sa_family);
455 
456 	/* Check address family to determine hook (if known) */
457 	if (iffam == NULL) {
458 		m_freem(m);
459 		log(LOG_WARNING, "%s: can't handle af%d\n",
460 		       ifp->if_xname, (int)dst->sa_family);
461 		return (EAFNOSUPPORT);
462 	}
463 
464 	/* Copy length before the mbuf gets invalidated */
465 	len = m->m_pkthdr.len;
466 
467 	/* Send packet; if hook is not connected, mbuf will get freed. */
468 	NG_SEND_DATA(error, *get_hook_from_iffam(priv, iffam), m, meta);
469 
470 	/* Update stats */
471 	if (error == 0) {
472 		ifp->if_obytes += len;
473 		ifp->if_opackets++;
474 	}
475 	return (error);
476 }
477 
478 /*
479  * This routine should never be called
480  */
481 
482 static void
483 ng_iface_start(struct ifnet *ifp)
484 {
485 	if_printf(ifp, "%s called?", __func__);
486 }
487 
488 /*
489  * Flash a packet by the BPF (requires prepending 4 byte AF header)
490  * Note the phoney mbuf; this is OK because BPF treats it read-only.
491  */
492 static void
493 ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
494 {
495 	KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
496 	if (ifp->if_bpf != NULL) {
497 		int32_t family4 = (int32_t)family;
498 		bpf_mtap2(ifp->if_bpf, &family4, sizeof(family4), m);
499 	}
500 }
501 
502 #ifdef DEBUG
503 /*
504  * Display an ioctl to the virtual interface
505  */
506 
507 static void
508 ng_iface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
509 {
510 	char   *str;
511 
512 	switch (command & IOC_DIRMASK) {
513 	case IOC_VOID:
514 		str = "IO";
515 		break;
516 	case IOC_OUT:
517 		str = "IOR";
518 		break;
519 	case IOC_IN:
520 		str = "IOW";
521 		break;
522 	case IOC_INOUT:
523 		str = "IORW";
524 		break;
525 	default:
526 		str = "IO??";
527 	}
528 	log(LOG_DEBUG, "%s: %s('%c', %d, char[%d])\n",
529 	       ifp->if_xname,
530 	       str,
531 	       IOCGROUP(command),
532 	       command & 0xff,
533 	       IOCPARM_LEN(command));
534 }
535 #endif /* DEBUG */
536 
537 /************************************************************************
538 			NETGRAPH NODE STUFF
539  ************************************************************************/
540 
541 /*
542  * Constructor for a node
543  */
544 static int
545 ng_iface_constructor(node_p node)
546 {
547 	char ifname[NG_IFACE_IFACE_NAME_MAX + 1];
548 	struct ifnet *ifp;
549 	priv_p priv;
550 	int error = 0;
551 
552 	/* Allocate node and interface private structures */
553 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
554 	if (priv == NULL)
555 		return (ENOMEM);
556 	MALLOC(ifp, struct ifnet *, sizeof(*ifp), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
557 	if (ifp == NULL) {
558 		FREE(priv, M_NETGRAPH_IFACE);
559 		return (ENOMEM);
560 	}
561 
562 	/* Link them together */
563 	ifp->if_softc = priv;
564 	priv->ifp = ifp;
565 
566 	/* Get an interface unit number */
567 	if ((error = ng_iface_get_unit(&priv->unit)) != 0) {
568 		FREE(ifp, M_NETGRAPH_IFACE);
569 		FREE(priv, M_NETGRAPH_IFACE);
570 		return (error);
571 	}
572 
573 	/* Link together node and private info */
574 	NG_NODE_SET_PRIVATE(node, priv);
575 	priv->node = node;
576 
577 	/* Initialize interface structure */
578 	if_initname(ifp, NG_IFACE_IFACE_NAME, priv->unit);
579 	ifp->if_output = ng_iface_output;
580 	ifp->if_start = ng_iface_start;
581 	ifp->if_ioctl = ng_iface_ioctl;
582 	ifp->if_watchdog = NULL;
583 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
584 	ifp->if_mtu = NG_IFACE_MTU_DEFAULT;
585 	ifp->if_flags = (IFF_SIMPLEX|IFF_POINTOPOINT|IFF_NOARP|IFF_MULTICAST);
586 	ifp->if_type = IFT_PROPVIRTUAL;		/* XXX */
587 	ifp->if_addrlen = 0;			/* XXX */
588 	ifp->if_hdrlen = 0;			/* XXX */
589 	ifp->if_baudrate = 64000;		/* XXX */
590 	TAILQ_INIT(&ifp->if_addrhead);
591 
592 	/* Give this node the same name as the interface (if possible) */
593 	bzero(ifname, sizeof(ifname));
594 	strlcpy(ifname, ifp->if_xname, sizeof(ifname));
595 	if (ng_name_node(node, ifname) != 0)
596 		log(LOG_WARNING, "%s: can't acquire netgraph name\n", ifname);
597 
598 	/* Attach the interface */
599 	if_attach(ifp);
600 	bpfattach(ifp, DLT_NULL, sizeof(u_int));
601 
602 	/* Done */
603 	return (0);
604 }
605 
606 /*
607  * Give our ok for a hook to be added
608  */
609 static int
610 ng_iface_newhook(node_p node, hook_p hook, const char *name)
611 {
612 	const iffam_p iffam = get_iffam_from_name(name);
613 	hook_p *hookptr;
614 
615 	if (iffam == NULL)
616 		return (EPFNOSUPPORT);
617 	hookptr = get_hook_from_iffam(NG_NODE_PRIVATE(node), iffam);
618 	if (*hookptr != NULL)
619 		return (EISCONN);
620 	*hookptr = hook;
621 	return (0);
622 }
623 
624 /*
625  * Receive a control message
626  */
627 static int
628 ng_iface_rcvmsg(node_p node, item_p item, hook_p lasthook)
629 {
630 	const priv_p priv = NG_NODE_PRIVATE(node);
631 	struct ifnet *const ifp = priv->ifp;
632 	struct ng_mesg *resp = NULL;
633 	int error = 0;
634 	struct ng_mesg *msg;
635 
636 	NGI_GET_MSG(item, msg);
637 	switch (msg->header.typecookie) {
638 	case NGM_IFACE_COOKIE:
639 		switch (msg->header.cmd) {
640 		case NGM_IFACE_GET_IFNAME:
641 		    {
642 			struct ng_iface_ifname *arg;
643 
644 			NG_MKRESPONSE(resp, msg, sizeof(*arg), M_NOWAIT);
645 			if (resp == NULL) {
646 				error = ENOMEM;
647 				break;
648 			}
649 			arg = (struct ng_iface_ifname *)resp->data;
650 			strlcpy(arg->ngif_name, ifp->if_xname,
651 			    sizeof(arg->ngif_name));
652 			break;
653 		    }
654 
655 		case NGM_IFACE_POINT2POINT:
656 		case NGM_IFACE_BROADCAST:
657 		    {
658 
659 			/* Deny request if interface is UP */
660 			if ((ifp->if_flags & IFF_UP) != 0)
661 				return (EBUSY);
662 
663 			/* Change flags */
664 			switch (msg->header.cmd) {
665 			case NGM_IFACE_POINT2POINT:
666 				ifp->if_flags |= IFF_POINTOPOINT;
667 				ifp->if_flags &= ~IFF_BROADCAST;
668 				break;
669 			case NGM_IFACE_BROADCAST:
670 				ifp->if_flags &= ~IFF_POINTOPOINT;
671 				ifp->if_flags |= IFF_BROADCAST;
672 				break;
673 			}
674 			break;
675 		    }
676 
677 		case NGM_IFACE_GET_IFINDEX:
678 			NG_MKRESPONSE(resp, msg, sizeof(uint32_t), M_NOWAIT);
679 			if (resp == NULL) {
680 				error = ENOMEM;
681 				break;
682 			}
683 			*((uint32_t *)resp->data) = priv->ifp->if_index;
684 			break;
685 
686 		default:
687 			error = EINVAL;
688 			break;
689 		}
690 		break;
691 	case NGM_CISCO_COOKIE:
692 		switch (msg->header.cmd) {
693 		case NGM_CISCO_GET_IPADDR:	/* we understand this too */
694 		    {
695 			struct ifaddr *ifa;
696 
697 			/* Return the first configured IP address */
698 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
699 				struct ng_cisco_ipaddr *ips;
700 
701 				if (ifa->ifa_addr->sa_family != AF_INET)
702 					continue;
703 				NG_MKRESPONSE(resp, msg, sizeof(ips), M_NOWAIT);
704 				if (resp == NULL) {
705 					error = ENOMEM;
706 					break;
707 				}
708 				ips = (struct ng_cisco_ipaddr *)resp->data;
709 				ips->ipaddr = ((struct sockaddr_in *)
710 						ifa->ifa_addr)->sin_addr;
711 				ips->netmask = ((struct sockaddr_in *)
712 						ifa->ifa_netmask)->sin_addr;
713 				break;
714 			}
715 
716 			/* No IP addresses on this interface? */
717 			if (ifa == NULL)
718 				error = EADDRNOTAVAIL;
719 			break;
720 		    }
721 		default:
722 			error = EINVAL;
723 			break;
724 		}
725 		break;
726 	default:
727 		error = EINVAL;
728 		break;
729 	}
730 	NG_RESPOND_MSG(error, node, item, resp);
731 	NG_FREE_MSG(msg);
732 	return (error);
733 }
734 
735 /*
736  * Recive data from a hook. Pass the packet to the correct input routine.
737  */
738 static int
739 ng_iface_rcvdata(hook_p hook, item_p item)
740 {
741 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
742 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
743 	struct ifnet *const ifp = priv->ifp;
744 	struct mbuf *m;
745 	int isr;
746 
747 	NGI_GET_M(item, m);
748 	NG_FREE_ITEM(item);
749 	/* Sanity checks */
750 	KASSERT(iffam != NULL, ("%s: iffam", __func__));
751 	M_ASSERTPKTHDR(m);
752 	if (m == NULL)
753 		return (EINVAL);
754 	if ((ifp->if_flags & IFF_UP) == 0) {
755 		NG_FREE_M(m);
756 		return (ENETDOWN);
757 	}
758 
759 	/* Update interface stats */
760 	ifp->if_ipackets++;
761 	ifp->if_ibytes += m->m_pkthdr.len;
762 
763 	/* Note receiving interface */
764 	m->m_pkthdr.rcvif = ifp;
765 
766 	/* Berkeley packet filter */
767 	ng_iface_bpftap(ifp, m, iffam->family);
768 
769 	/* Send packet */
770 	switch (iffam->family) {
771 #ifdef INET
772 	case AF_INET:
773 		isr = NETISR_IP;
774 		break;
775 #endif
776 #ifdef INET6
777 	case AF_INET6:
778 		isr = NETISR_IPV6;
779 		break;
780 #endif
781 #ifdef IPX
782 	case AF_IPX:
783 		isr = NETISR_IPX;
784 		break;
785 #endif
786 #ifdef NETATALK
787 	case AF_APPLETALK:
788 		isr = NETISR_ATALK2;
789 		break;
790 #endif
791 	default:
792 		m_freem(m);
793 		return (EAFNOSUPPORT);
794 	}
795 	/* First chunk of an mbuf contains good junk */
796 	if (harvest.point_to_point)
797 		random_harvest(m, 16, 3, 0, RANDOM_NET);
798 	netisr_dispatch(isr, m);
799 	return (0);
800 }
801 
802 /*
803  * Shutdown and remove the node and its associated interface.
804  */
805 static int
806 ng_iface_shutdown(node_p node)
807 {
808 	const priv_p priv = NG_NODE_PRIVATE(node);
809 
810 	bpfdetach(priv->ifp);
811 	if_detach(priv->ifp);
812 	FREE(priv->ifp, M_NETGRAPH_IFACE);
813 	priv->ifp = NULL;
814 	ng_iface_free_unit(priv->unit);
815 	FREE(priv, M_NETGRAPH_IFACE);
816 	NG_NODE_SET_PRIVATE(node, NULL);
817 	NG_NODE_UNREF(node);
818 	return (0);
819 }
820 
821 /*
822  * Hook disconnection. Note that we do *not* shutdown when all
823  * hooks have been disconnected.
824  */
825 static int
826 ng_iface_disconnect(hook_p hook)
827 {
828 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
829 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
830 
831 	if (iffam == NULL)
832 		panic(__func__);
833 	*get_hook_from_iffam(priv, iffam) = NULL;
834 	return (0);
835 }
836 
837