xref: /freebsd/sys/netgraph/ng_iface.c (revision 6e0da4f753ed6b5d26395001a6194b4fdea70177)
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/lock.h>
65 #include <sys/malloc.h>
66 #include <sys/mbuf.h>
67 #include <sys/mutex.h>
68 #include <sys/errno.h>
69 #include <sys/random.h>
70 #include <sys/sockio.h>
71 #include <sys/socket.h>
72 #include <sys/syslog.h>
73 #include <sys/libkern.h>
74 
75 #include <net/if.h>
76 #include <net/if_types.h>
77 #include <net/bpf.h>
78 #include <net/netisr.h>
79 
80 #include <netinet/in.h>
81 
82 #include <netgraph/ng_message.h>
83 #include <netgraph/netgraph.h>
84 #include <netgraph/ng_parse.h>
85 #include <netgraph/ng_iface.h>
86 #include <netgraph/ng_cisco.h>
87 
88 #ifdef NG_SEPARATE_MALLOC
89 MALLOC_DEFINE(M_NETGRAPH_IFACE, "netgraph_iface", "netgraph iface node ");
90 #else
91 #define M_NETGRAPH_IFACE M_NETGRAPH
92 #endif
93 
94 /* This struct describes one address family */
95 struct iffam {
96 	sa_family_t	family;		/* Address family */
97 	const char	*hookname;	/* Name for hook */
98 };
99 typedef const struct iffam *iffam_p;
100 
101 /* List of address families supported by our interface */
102 const static struct iffam gFamilies[] = {
103 	{ AF_INET,	NG_IFACE_HOOK_INET	},
104 	{ AF_INET6,	NG_IFACE_HOOK_INET6	},
105 	{ AF_APPLETALK,	NG_IFACE_HOOK_ATALK	},
106 	{ AF_IPX,	NG_IFACE_HOOK_IPX	},
107 	{ AF_ATM,	NG_IFACE_HOOK_ATM	},
108 	{ AF_NATM,	NG_IFACE_HOOK_NATM	},
109 };
110 #define NUM_FAMILIES		(sizeof(gFamilies) / sizeof(*gFamilies))
111 
112 /* Node private data */
113 struct ng_iface_private {
114 	struct	ifnet *ifp;		/* Our interface */
115 	int	unit;			/* Interface unit number */
116 	node_p	node;			/* Our netgraph node */
117 	hook_p	hooks[NUM_FAMILIES];	/* Hook for each address family */
118 };
119 typedef struct ng_iface_private *priv_p;
120 
121 /* Interface methods */
122 static void	ng_iface_start(struct ifnet *ifp);
123 static int	ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
124 static int	ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
125 			struct sockaddr *dst, struct rtentry *rt0);
126 static void	ng_iface_bpftap(struct ifnet *ifp,
127 			struct mbuf *m, sa_family_t family);
128 #ifdef DEBUG
129 static void	ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
130 #endif
131 
132 /* Netgraph methods */
133 static ng_constructor_t	ng_iface_constructor;
134 static ng_rcvmsg_t	ng_iface_rcvmsg;
135 static ng_shutdown_t	ng_iface_shutdown;
136 static ng_newhook_t	ng_iface_newhook;
137 static ng_rcvdata_t	ng_iface_rcvdata;
138 static ng_disconnect_t	ng_iface_disconnect;
139 
140 /* Helper stuff */
141 static iffam_p	get_iffam_from_af(sa_family_t family);
142 static iffam_p	get_iffam_from_hook(priv_p priv, hook_p hook);
143 static iffam_p	get_iffam_from_name(const char *name);
144 static hook_p  *get_hook_from_iffam(priv_p priv, iffam_p iffam);
145 
146 /* Parse type for struct ng_iface_ifname */
147 static const struct ng_parse_fixedstring_info ng_iface_ifname_info = {
148 	NG_IFACE_IFACE_NAME_MAX + 1
149 };
150 static const struct ng_parse_type ng_iface_ifname_type = {
151 	&ng_parse_fixedstring_type,
152 	&ng_iface_ifname_info
153 };
154 
155 /* Parse type for struct ng_cisco_ipaddr */
156 static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
157 	= NG_CISCO_IPADDR_TYPE_INFO;
158 static const struct ng_parse_type ng_cisco_ipaddr_type = {
159 	&ng_parse_struct_type,
160 	&ng_cisco_ipaddr_type_fields
161 };
162 
163 /* List of commands and how to convert arguments to/from ASCII */
164 static const struct ng_cmdlist ng_iface_cmds[] = {
165 	{
166 	  NGM_IFACE_COOKIE,
167 	  NGM_IFACE_GET_IFNAME,
168 	  "getifname",
169 	  NULL,
170 	  &ng_iface_ifname_type
171 	},
172 	{
173 	  NGM_IFACE_COOKIE,
174 	  NGM_IFACE_POINT2POINT,
175 	  "point2point",
176 	  NULL,
177 	  NULL
178 	},
179 	{
180 	  NGM_IFACE_COOKIE,
181 	  NGM_IFACE_BROADCAST,
182 	  "broadcast",
183 	  NULL,
184 	  NULL
185 	},
186 	{
187 	  NGM_CISCO_COOKIE,
188 	  NGM_CISCO_GET_IPADDR,
189 	  "getipaddr",
190 	  NULL,
191 	  &ng_cisco_ipaddr_type
192 	},
193 	{
194 	  NGM_IFACE_COOKIE,
195 	  NGM_IFACE_GET_IFINDEX,
196 	  "getifindex",
197 	  NULL,
198 	  &ng_parse_uint32_type
199 	},
200 	{ 0 }
201 };
202 
203 /* Node type descriptor */
204 static struct ng_type typestruct = {
205 	.version =	NG_ABI_VERSION,
206 	.name =		NG_IFACE_NODE_TYPE,
207 	.constructor =	ng_iface_constructor,
208 	.rcvmsg =	ng_iface_rcvmsg,
209 	.shutdown =	ng_iface_shutdown,
210 	.newhook =	ng_iface_newhook,
211 	.rcvdata =	ng_iface_rcvdata,
212 	.disconnect =	ng_iface_disconnect,
213 	.cmdlist =	ng_iface_cmds,
214 };
215 NETGRAPH_INIT(iface, &typestruct);
216 
217 /* We keep a bitmap indicating which unit numbers are free.
218    One means the unit number is free, zero means it's taken. */
219 static int	*ng_iface_units = NULL;
220 static int	ng_iface_units_len = 0;
221 static int	ng_units_in_use = 0;
222 
223 #define UNITS_BITSPERWORD	(sizeof(*ng_iface_units) * NBBY)
224 
225 static struct mtx	ng_iface_mtx;
226 MTX_SYSINIT(ng_iface, &ng_iface_mtx, "ng_iface", MTX_DEF);
227 
228 /************************************************************************
229 			HELPER STUFF
230  ************************************************************************/
231 
232 /*
233  * Get the family descriptor from the family ID
234  */
235 static __inline iffam_p
236 get_iffam_from_af(sa_family_t family)
237 {
238 	iffam_p iffam;
239 	int k;
240 
241 	for (k = 0; k < NUM_FAMILIES; k++) {
242 		iffam = &gFamilies[k];
243 		if (iffam->family == family)
244 			return (iffam);
245 	}
246 	return (NULL);
247 }
248 
249 /*
250  * Get the family descriptor from the hook
251  */
252 static __inline iffam_p
253 get_iffam_from_hook(priv_p priv, hook_p hook)
254 {
255 	int k;
256 
257 	for (k = 0; k < NUM_FAMILIES; k++)
258 		if (priv->hooks[k] == hook)
259 			return (&gFamilies[k]);
260 	return (NULL);
261 }
262 
263 /*
264  * Get the hook from the iffam descriptor
265  */
266 
267 static __inline hook_p *
268 get_hook_from_iffam(priv_p priv, iffam_p iffam)
269 {
270 	return (&priv->hooks[iffam - gFamilies]);
271 }
272 
273 /*
274  * Get the iffam descriptor from the name
275  */
276 static __inline iffam_p
277 get_iffam_from_name(const char *name)
278 {
279 	iffam_p iffam;
280 	int k;
281 
282 	for (k = 0; k < NUM_FAMILIES; k++) {
283 		iffam = &gFamilies[k];
284 		if (!strcmp(iffam->hookname, name))
285 			return (iffam);
286 	}
287 	return (NULL);
288 }
289 
290 /*
291  * Find the first free unit number for a new interface.
292  * Increase the size of the unit bitmap as necessary.
293  */
294 static __inline int
295 ng_iface_get_unit(int *unit)
296 {
297 	int index, bit;
298 
299 	mtx_lock(&ng_iface_mtx);
300 	for (index = 0; index < ng_iface_units_len
301 	    && ng_iface_units[index] == 0; index++);
302 	if (index == ng_iface_units_len) {		/* extend array */
303 		int i, *newarray, newlen;
304 
305 		newlen = (2 * ng_iface_units_len) + 4;
306 		MALLOC(newarray, int *, newlen * sizeof(*ng_iface_units),
307 		    M_NETGRAPH_IFACE, M_NOWAIT);
308 		if (newarray == NULL) {
309 			mtx_unlock(&ng_iface_mtx);
310 			return (ENOMEM);
311 		}
312 		bcopy(ng_iface_units, newarray,
313 		    ng_iface_units_len * sizeof(*ng_iface_units));
314 		for (i = ng_iface_units_len; i < newlen; i++)
315 			newarray[i] = ~0;
316 		if (ng_iface_units != NULL)
317 			FREE(ng_iface_units, M_NETGRAPH_IFACE);
318 		ng_iface_units = newarray;
319 		ng_iface_units_len = newlen;
320 	}
321 	bit = ffs(ng_iface_units[index]) - 1;
322 	KASSERT(bit >= 0 && bit <= UNITS_BITSPERWORD - 1,
323 	    ("%s: word=%d bit=%d", __func__, ng_iface_units[index], bit));
324 	ng_iface_units[index] &= ~(1 << bit);
325 	*unit = (index * UNITS_BITSPERWORD) + bit;
326 	ng_units_in_use++;
327 	mtx_unlock(&ng_iface_mtx);
328 	return (0);
329 }
330 
331 /*
332  * Free a no longer needed unit number.
333  */
334 static __inline void
335 ng_iface_free_unit(int unit)
336 {
337 	int index, bit;
338 
339 	index = unit / UNITS_BITSPERWORD;
340 	bit = unit % UNITS_BITSPERWORD;
341 	mtx_lock(&ng_iface_mtx);
342 	KASSERT(index < ng_iface_units_len,
343 	    ("%s: unit=%d len=%d", __func__, unit, ng_iface_units_len));
344 	KASSERT((ng_iface_units[index] & (1 << bit)) == 0,
345 	    ("%s: unit=%d is free", __func__, unit));
346 	ng_iface_units[index] |= (1 << bit);
347 	/*
348 	 * XXX We could think about reducing the size of ng_iface_units[]
349 	 * XXX here if the last portion is all ones
350 	 * XXX At least free it if no more units.
351 	 * Needed if we are to eventually be able to unload.
352 	 */
353 	ng_units_in_use--;
354 	if (ng_units_in_use == 0) { /* XXX make SMP safe */
355 		FREE(ng_iface_units, M_NETGRAPH_IFACE);
356 		ng_iface_units_len = 0;
357 		ng_iface_units = NULL;
358 	}
359 	mtx_unlock(&ng_iface_mtx);
360 }
361 
362 /************************************************************************
363 			INTERFACE STUFF
364  ************************************************************************/
365 
366 /*
367  * Process an ioctl for the virtual interface
368  */
369 static int
370 ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
371 {
372 	struct ifreq *const ifr = (struct ifreq *) data;
373 	int s, error = 0;
374 
375 #ifdef DEBUG
376 	ng_iface_print_ioctl(ifp, command, data);
377 #endif
378 	s = splimp();
379 	switch (command) {
380 
381 	/* These two are mostly handled at a higher layer */
382 	case SIOCSIFADDR:
383 		ifp->if_flags |= (IFF_UP | IFF_RUNNING);
384 		ifp->if_flags &= ~(IFF_OACTIVE);
385 		break;
386 	case SIOCGIFADDR:
387 		break;
388 
389 	/* Set flags */
390 	case SIOCSIFFLAGS:
391 		/*
392 		 * If the interface is marked up and stopped, then start it.
393 		 * If it is marked down and running, then stop it.
394 		 */
395 		if (ifr->ifr_flags & IFF_UP) {
396 			if (!(ifp->if_flags & IFF_RUNNING)) {
397 				ifp->if_flags &= ~(IFF_OACTIVE);
398 				ifp->if_flags |= IFF_RUNNING;
399 			}
400 		} else {
401 			if (ifp->if_flags & IFF_RUNNING)
402 				ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
403 		}
404 		break;
405 
406 	/* Set the interface MTU */
407 	case SIOCSIFMTU:
408 		if (ifr->ifr_mtu > NG_IFACE_MTU_MAX
409 		    || ifr->ifr_mtu < NG_IFACE_MTU_MIN)
410 			error = EINVAL;
411 		else
412 			ifp->if_mtu = ifr->ifr_mtu;
413 		break;
414 
415 	/* Stuff that's not supported */
416 	case SIOCADDMULTI:
417 	case SIOCDELMULTI:
418 		error = 0;
419 		break;
420 	case SIOCSIFPHYS:
421 		error = EOPNOTSUPP;
422 		break;
423 
424 	default:
425 		error = EINVAL;
426 		break;
427 	}
428 	(void) splx(s);
429 	return (error);
430 }
431 
432 /*
433  * This routine is called to deliver a packet out the interface.
434  * We simply look at the address family and relay the packet to
435  * the corresponding hook, if it exists and is connected.
436  */
437 
438 static int
439 ng_iface_output(struct ifnet *ifp, struct mbuf *m,
440 		struct sockaddr *dst, struct rtentry *rt0)
441 {
442 	const priv_p priv = (priv_p) ifp->if_softc;
443 	const iffam_p iffam = get_iffam_from_af(dst->sa_family);
444 	int len, error = 0;
445 
446 	/* Check interface flags */
447 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
448 		m_freem(m);
449 		return (ENETDOWN);
450 	}
451 
452 	/* BPF writes need to be handled specially */
453 	if (dst->sa_family == AF_UNSPEC) {
454 		if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
455 			return (ENOBUFS);
456 		dst->sa_family = (sa_family_t)*mtod(m, int32_t *);
457 		m->m_data += 4;
458 		m->m_len -= 4;
459 		m->m_pkthdr.len -= 4;
460 	}
461 
462 	/* Berkeley packet filter */
463 	ng_iface_bpftap(ifp, m, dst->sa_family);
464 
465 	/* Check address family to determine hook (if known) */
466 	if (iffam == NULL) {
467 		m_freem(m);
468 		log(LOG_WARNING, "%s: can't handle af%d\n",
469 		       ifp->if_xname, (int)dst->sa_family);
470 		return (EAFNOSUPPORT);
471 	}
472 
473 	/* Copy length before the mbuf gets invalidated */
474 	len = m->m_pkthdr.len;
475 
476 	/* Send packet; if hook is not connected, mbuf will get freed. */
477 	NG_SEND_DATA_ONLY(error, *get_hook_from_iffam(priv, iffam), m);
478 
479 	/* Update stats */
480 	if (error == 0) {
481 		ifp->if_obytes += len;
482 		ifp->if_opackets++;
483 	}
484 	return (error);
485 }
486 
487 /*
488  * This routine should never be called
489  */
490 
491 static void
492 ng_iface_start(struct ifnet *ifp)
493 {
494 	if_printf(ifp, "%s called?", __func__);
495 }
496 
497 /*
498  * Flash a packet by the BPF (requires prepending 4 byte AF header)
499  * Note the phoney mbuf; this is OK because BPF treats it read-only.
500  */
501 static void
502 ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
503 {
504 	KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
505 	if (ifp->if_bpf != NULL) {
506 		int32_t family4 = (int32_t)family;
507 		bpf_mtap2(ifp->if_bpf, &family4, sizeof(family4), m);
508 	}
509 }
510 
511 #ifdef DEBUG
512 /*
513  * Display an ioctl to the virtual interface
514  */
515 
516 static void
517 ng_iface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
518 {
519 	char   *str;
520 
521 	switch (command & IOC_DIRMASK) {
522 	case IOC_VOID:
523 		str = "IO";
524 		break;
525 	case IOC_OUT:
526 		str = "IOR";
527 		break;
528 	case IOC_IN:
529 		str = "IOW";
530 		break;
531 	case IOC_INOUT:
532 		str = "IORW";
533 		break;
534 	default:
535 		str = "IO??";
536 	}
537 	log(LOG_DEBUG, "%s: %s('%c', %d, char[%d])\n",
538 	       ifp->if_xname,
539 	       str,
540 	       IOCGROUP(command),
541 	       command & 0xff,
542 	       IOCPARM_LEN(command));
543 }
544 #endif /* DEBUG */
545 
546 /************************************************************************
547 			NETGRAPH NODE STUFF
548  ************************************************************************/
549 
550 /*
551  * Constructor for a node
552  */
553 static int
554 ng_iface_constructor(node_p node)
555 {
556 	char ifname[NG_IFACE_IFACE_NAME_MAX + 1];
557 	struct ifnet *ifp;
558 	priv_p priv;
559 	int error = 0;
560 
561 	/* Allocate node and interface private structures */
562 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
563 	if (priv == NULL)
564 		return (ENOMEM);
565 	MALLOC(ifp, struct ifnet *, sizeof(*ifp), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
566 	if (ifp == NULL) {
567 		FREE(priv, M_NETGRAPH_IFACE);
568 		return (ENOMEM);
569 	}
570 
571 	/* Link them together */
572 	ifp->if_softc = priv;
573 	priv->ifp = ifp;
574 
575 	/* Get an interface unit number */
576 	if ((error = ng_iface_get_unit(&priv->unit)) != 0) {
577 		FREE(ifp, M_NETGRAPH_IFACE);
578 		FREE(priv, M_NETGRAPH_IFACE);
579 		return (error);
580 	}
581 
582 	/* Link together node and private info */
583 	NG_NODE_SET_PRIVATE(node, priv);
584 	priv->node = node;
585 
586 	/* Initialize interface structure */
587 	if_initname(ifp, NG_IFACE_IFACE_NAME, priv->unit);
588 	ifp->if_output = ng_iface_output;
589 	ifp->if_start = ng_iface_start;
590 	ifp->if_ioctl = ng_iface_ioctl;
591 	ifp->if_watchdog = NULL;
592 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
593 	ifp->if_mtu = NG_IFACE_MTU_DEFAULT;
594 	ifp->if_flags = (IFF_SIMPLEX|IFF_POINTOPOINT|IFF_NOARP|IFF_MULTICAST);
595 	ifp->if_type = IFT_PROPVIRTUAL;		/* XXX */
596 	ifp->if_addrlen = 0;			/* XXX */
597 	ifp->if_hdrlen = 0;			/* XXX */
598 	ifp->if_baudrate = 64000;		/* XXX */
599 	TAILQ_INIT(&ifp->if_addrhead);
600 
601 	/* Give this node the same name as the interface (if possible) */
602 	bzero(ifname, sizeof(ifname));
603 	strlcpy(ifname, ifp->if_xname, sizeof(ifname));
604 	if (ng_name_node(node, ifname) != 0)
605 		log(LOG_WARNING, "%s: can't acquire netgraph name\n", ifname);
606 
607 	/* Attach the interface */
608 	if_attach(ifp);
609 	bpfattach(ifp, DLT_NULL, sizeof(u_int));
610 
611 	/* Done */
612 	return (0);
613 }
614 
615 /*
616  * Give our ok for a hook to be added
617  */
618 static int
619 ng_iface_newhook(node_p node, hook_p hook, const char *name)
620 {
621 	const iffam_p iffam = get_iffam_from_name(name);
622 	hook_p *hookptr;
623 
624 	if (iffam == NULL)
625 		return (EPFNOSUPPORT);
626 	hookptr = get_hook_from_iffam(NG_NODE_PRIVATE(node), iffam);
627 	if (*hookptr != NULL)
628 		return (EISCONN);
629 	*hookptr = hook;
630 	return (0);
631 }
632 
633 /*
634  * Receive a control message
635  */
636 static int
637 ng_iface_rcvmsg(node_p node, item_p item, hook_p lasthook)
638 {
639 	const priv_p priv = NG_NODE_PRIVATE(node);
640 	struct ifnet *const ifp = priv->ifp;
641 	struct ng_mesg *resp = NULL;
642 	int error = 0;
643 	struct ng_mesg *msg;
644 
645 	NGI_GET_MSG(item, msg);
646 	switch (msg->header.typecookie) {
647 	case NGM_IFACE_COOKIE:
648 		switch (msg->header.cmd) {
649 		case NGM_IFACE_GET_IFNAME:
650 		    {
651 			struct ng_iface_ifname *arg;
652 
653 			NG_MKRESPONSE(resp, msg, sizeof(*arg), M_NOWAIT);
654 			if (resp == NULL) {
655 				error = ENOMEM;
656 				break;
657 			}
658 			arg = (struct ng_iface_ifname *)resp->data;
659 			strlcpy(arg->ngif_name, ifp->if_xname,
660 			    sizeof(arg->ngif_name));
661 			break;
662 		    }
663 
664 		case NGM_IFACE_POINT2POINT:
665 		case NGM_IFACE_BROADCAST:
666 		    {
667 
668 			/* Deny request if interface is UP */
669 			if ((ifp->if_flags & IFF_UP) != 0)
670 				return (EBUSY);
671 
672 			/* Change flags */
673 			switch (msg->header.cmd) {
674 			case NGM_IFACE_POINT2POINT:
675 				ifp->if_flags |= IFF_POINTOPOINT;
676 				ifp->if_flags &= ~IFF_BROADCAST;
677 				break;
678 			case NGM_IFACE_BROADCAST:
679 				ifp->if_flags &= ~IFF_POINTOPOINT;
680 				ifp->if_flags |= IFF_BROADCAST;
681 				break;
682 			}
683 			break;
684 		    }
685 
686 		case NGM_IFACE_GET_IFINDEX:
687 			NG_MKRESPONSE(resp, msg, sizeof(uint32_t), M_NOWAIT);
688 			if (resp == NULL) {
689 				error = ENOMEM;
690 				break;
691 			}
692 			*((uint32_t *)resp->data) = priv->ifp->if_index;
693 			break;
694 
695 		default:
696 			error = EINVAL;
697 			break;
698 		}
699 		break;
700 	case NGM_CISCO_COOKIE:
701 		switch (msg->header.cmd) {
702 		case NGM_CISCO_GET_IPADDR:	/* we understand this too */
703 		    {
704 			struct ifaddr *ifa;
705 
706 			/* Return the first configured IP address */
707 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
708 				struct ng_cisco_ipaddr *ips;
709 
710 				if (ifa->ifa_addr->sa_family != AF_INET)
711 					continue;
712 				NG_MKRESPONSE(resp, msg, sizeof(ips), M_NOWAIT);
713 				if (resp == NULL) {
714 					error = ENOMEM;
715 					break;
716 				}
717 				ips = (struct ng_cisco_ipaddr *)resp->data;
718 				ips->ipaddr = ((struct sockaddr_in *)
719 						ifa->ifa_addr)->sin_addr;
720 				ips->netmask = ((struct sockaddr_in *)
721 						ifa->ifa_netmask)->sin_addr;
722 				break;
723 			}
724 
725 			/* No IP addresses on this interface? */
726 			if (ifa == NULL)
727 				error = EADDRNOTAVAIL;
728 			break;
729 		    }
730 		default:
731 			error = EINVAL;
732 			break;
733 		}
734 		break;
735 	case NGM_FLOW_COOKIE:
736 		switch (msg->header.cmd) {
737 		case NGM_LINK_IS_UP:
738 			ifp->if_flags |= IFF_RUNNING;
739 			break;
740 		case NGM_LINK_IS_DOWN:
741 			ifp->if_flags &= ~IFF_RUNNING;
742 			break;
743 		default:
744 			break;
745 		}
746 		break;
747 	default:
748 		error = EINVAL;
749 		break;
750 	}
751 	NG_RESPOND_MSG(error, node, item, resp);
752 	NG_FREE_MSG(msg);
753 	return (error);
754 }
755 
756 /*
757  * Recive data from a hook. Pass the packet to the correct input routine.
758  */
759 static int
760 ng_iface_rcvdata(hook_p hook, item_p item)
761 {
762 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
763 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
764 	struct ifnet *const ifp = priv->ifp;
765 	struct mbuf *m;
766 	int isr;
767 
768 	NGI_GET_M(item, m);
769 	NG_FREE_ITEM(item);
770 	/* Sanity checks */
771 	KASSERT(iffam != NULL, ("%s: iffam", __func__));
772 	M_ASSERTPKTHDR(m);
773 	if ((ifp->if_flags & IFF_UP) == 0) {
774 		NG_FREE_M(m);
775 		return (ENETDOWN);
776 	}
777 
778 	/* Update interface stats */
779 	ifp->if_ipackets++;
780 	ifp->if_ibytes += m->m_pkthdr.len;
781 
782 	/* Note receiving interface */
783 	m->m_pkthdr.rcvif = ifp;
784 
785 	/* Berkeley packet filter */
786 	ng_iface_bpftap(ifp, m, iffam->family);
787 
788 	/* Send packet */
789 	switch (iffam->family) {
790 #ifdef INET
791 	case AF_INET:
792 		isr = NETISR_IP;
793 		break;
794 #endif
795 #ifdef INET6
796 	case AF_INET6:
797 		isr = NETISR_IPV6;
798 		break;
799 #endif
800 #ifdef IPX
801 	case AF_IPX:
802 		isr = NETISR_IPX;
803 		break;
804 #endif
805 #ifdef NETATALK
806 	case AF_APPLETALK:
807 		isr = NETISR_ATALK2;
808 		break;
809 #endif
810 	default:
811 		m_freem(m);
812 		return (EAFNOSUPPORT);
813 	}
814 	/* First chunk of an mbuf contains good junk */
815 	if (harvest.point_to_point)
816 		random_harvest(m, 16, 3, 0, RANDOM_NET);
817 	netisr_dispatch(isr, m);
818 	return (0);
819 }
820 
821 /*
822  * Shutdown and remove the node and its associated interface.
823  */
824 static int
825 ng_iface_shutdown(node_p node)
826 {
827 	const priv_p priv = NG_NODE_PRIVATE(node);
828 
829 	bpfdetach(priv->ifp);
830 	if_detach(priv->ifp);
831 	FREE(priv->ifp, M_NETGRAPH_IFACE);
832 	priv->ifp = NULL;
833 	ng_iface_free_unit(priv->unit);
834 	FREE(priv, M_NETGRAPH_IFACE);
835 	NG_NODE_SET_PRIVATE(node, NULL);
836 	NG_NODE_UNREF(node);
837 	return (0);
838 }
839 
840 /*
841  * Hook disconnection. Note that we do *not* shutdown when all
842  * hooks have been disconnected.
843  */
844 static int
845 ng_iface_disconnect(hook_p hook)
846 {
847 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
848 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
849 
850 	if (iffam == NULL)
851 		panic(__func__);
852 	*get_hook_from_iffam(priv, iffam) = NULL;
853 	return (0);
854 }
855 
856