xref: /freebsd/sys/netgraph/ng_iface.c (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
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/lock.h>
63 #include <sys/malloc.h>
64 #include <sys/mbuf.h>
65 #include <sys/mutex.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 
73 #include <net/if.h>
74 #include <net/if_types.h>
75 #include <net/bpf.h>
76 #include <net/netisr.h>
77 
78 #include <netinet/in.h>
79 
80 #include <netgraph/ng_message.h>
81 #include <netgraph/netgraph.h>
82 #include <netgraph/ng_parse.h>
83 #include <netgraph/ng_iface.h>
84 #include <netgraph/ng_cisco.h>
85 
86 #ifdef NG_SEPARATE_MALLOC
87 MALLOC_DEFINE(M_NETGRAPH_IFACE, "netgraph_iface", "netgraph iface node ");
88 #else
89 #define M_NETGRAPH_IFACE M_NETGRAPH
90 #endif
91 
92 /* This struct describes one address family */
93 struct iffam {
94 	sa_family_t	family;		/* Address family */
95 	const char	*hookname;	/* Name for hook */
96 };
97 typedef const struct iffam *iffam_p;
98 
99 /* List of address families supported by our interface */
100 const static struct iffam gFamilies[] = {
101 	{ AF_INET,	NG_IFACE_HOOK_INET	},
102 	{ AF_INET6,	NG_IFACE_HOOK_INET6	},
103 	{ AF_APPLETALK,	NG_IFACE_HOOK_ATALK	},
104 	{ AF_IPX,	NG_IFACE_HOOK_IPX	},
105 	{ AF_ATM,	NG_IFACE_HOOK_ATM	},
106 	{ AF_NATM,	NG_IFACE_HOOK_NATM	},
107 };
108 #define NUM_FAMILIES		(sizeof(gFamilies) / sizeof(*gFamilies))
109 
110 /* Node private data */
111 struct ng_iface_private {
112 	struct	ifnet *ifp;		/* Our interface */
113 	int	unit;			/* Interface unit number */
114 	node_p	node;			/* Our netgraph node */
115 	hook_p	hooks[NUM_FAMILIES];	/* Hook for each address family */
116 };
117 typedef struct ng_iface_private *priv_p;
118 
119 /* Interface methods */
120 static void	ng_iface_start(struct ifnet *ifp);
121 static int	ng_iface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
122 static int	ng_iface_output(struct ifnet *ifp, struct mbuf *m0,
123 			struct sockaddr *dst, struct rtentry *rt0);
124 static void	ng_iface_bpftap(struct ifnet *ifp,
125 			struct mbuf *m, sa_family_t family);
126 #ifdef DEBUG
127 static void	ng_iface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
128 #endif
129 
130 /* Netgraph methods */
131 static ng_constructor_t	ng_iface_constructor;
132 static ng_rcvmsg_t	ng_iface_rcvmsg;
133 static ng_shutdown_t	ng_iface_shutdown;
134 static ng_newhook_t	ng_iface_newhook;
135 static ng_rcvdata_t	ng_iface_rcvdata;
136 static ng_disconnect_t	ng_iface_disconnect;
137 
138 /* Helper stuff */
139 static iffam_p	get_iffam_from_af(sa_family_t family);
140 static iffam_p	get_iffam_from_hook(priv_p priv, hook_p hook);
141 static iffam_p	get_iffam_from_name(const char *name);
142 static hook_p  *get_hook_from_iffam(priv_p priv, iffam_p iffam);
143 
144 /* Parse type for struct ng_iface_ifname */
145 static const struct ng_parse_fixedstring_info ng_iface_ifname_info = {
146 	NG_IFACE_IFACE_NAME_MAX + 1
147 };
148 static const struct ng_parse_type ng_iface_ifname_type = {
149 	&ng_parse_fixedstring_type,
150 	&ng_iface_ifname_info
151 };
152 
153 /* Parse type for struct ng_cisco_ipaddr */
154 static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
155 	= NG_CISCO_IPADDR_TYPE_INFO;
156 static const struct ng_parse_type ng_cisco_ipaddr_type = {
157 	&ng_parse_struct_type,
158 	&ng_cisco_ipaddr_type_fields
159 };
160 
161 /* List of commands and how to convert arguments to/from ASCII */
162 static const struct ng_cmdlist ng_iface_cmds[] = {
163 	{
164 	  NGM_IFACE_COOKIE,
165 	  NGM_IFACE_GET_IFNAME,
166 	  "getifname",
167 	  NULL,
168 	  &ng_iface_ifname_type
169 	},
170 	{
171 	  NGM_IFACE_COOKIE,
172 	  NGM_IFACE_POINT2POINT,
173 	  "point2point",
174 	  NULL,
175 	  NULL
176 	},
177 	{
178 	  NGM_IFACE_COOKIE,
179 	  NGM_IFACE_BROADCAST,
180 	  "broadcast",
181 	  NULL,
182 	  NULL
183 	},
184 	{
185 	  NGM_CISCO_COOKIE,
186 	  NGM_CISCO_GET_IPADDR,
187 	  "getipaddr",
188 	  NULL,
189 	  &ng_cisco_ipaddr_type
190 	},
191 	{
192 	  NGM_IFACE_COOKIE,
193 	  NGM_IFACE_GET_IFINDEX,
194 	  "getifindex",
195 	  NULL,
196 	  &ng_parse_uint32_type
197 	},
198 	{ 0 }
199 };
200 
201 /* Node type descriptor */
202 static struct ng_type typestruct = {
203 	.version =	NG_ABI_VERSION,
204 	.name =		NG_IFACE_NODE_TYPE,
205 	.constructor =	ng_iface_constructor,
206 	.rcvmsg =	ng_iface_rcvmsg,
207 	.shutdown =	ng_iface_shutdown,
208 	.newhook =	ng_iface_newhook,
209 	.rcvdata =	ng_iface_rcvdata,
210 	.disconnect =	ng_iface_disconnect,
211 	.cmdlist =	ng_iface_cmds,
212 };
213 NETGRAPH_INIT(iface, &typestruct);
214 
215 /* We keep a bitmap indicating which unit numbers are free.
216    One means the unit number is free, zero means it's taken. */
217 static int	*ng_iface_units = NULL;
218 static int	ng_iface_units_len = 0;
219 static int	ng_units_in_use = 0;
220 
221 #define UNITS_BITSPERWORD	(sizeof(*ng_iface_units) * NBBY)
222 
223 static struct mtx	ng_iface_mtx;
224 MTX_SYSINIT(ng_iface, &ng_iface_mtx, "ng_iface", MTX_DEF);
225 
226 /************************************************************************
227 			HELPER STUFF
228  ************************************************************************/
229 
230 /*
231  * Get the family descriptor from the family ID
232  */
233 static __inline iffam_p
234 get_iffam_from_af(sa_family_t family)
235 {
236 	iffam_p iffam;
237 	int k;
238 
239 	for (k = 0; k < NUM_FAMILIES; k++) {
240 		iffam = &gFamilies[k];
241 		if (iffam->family == family)
242 			return (iffam);
243 	}
244 	return (NULL);
245 }
246 
247 /*
248  * Get the family descriptor from the hook
249  */
250 static __inline iffam_p
251 get_iffam_from_hook(priv_p priv, hook_p hook)
252 {
253 	int k;
254 
255 	for (k = 0; k < NUM_FAMILIES; k++)
256 		if (priv->hooks[k] == hook)
257 			return (&gFamilies[k]);
258 	return (NULL);
259 }
260 
261 /*
262  * Get the hook from the iffam descriptor
263  */
264 
265 static __inline hook_p *
266 get_hook_from_iffam(priv_p priv, iffam_p iffam)
267 {
268 	return (&priv->hooks[iffam - gFamilies]);
269 }
270 
271 /*
272  * Get the iffam descriptor from the name
273  */
274 static __inline iffam_p
275 get_iffam_from_name(const char *name)
276 {
277 	iffam_p iffam;
278 	int k;
279 
280 	for (k = 0; k < NUM_FAMILIES; k++) {
281 		iffam = &gFamilies[k];
282 		if (!strcmp(iffam->hookname, name))
283 			return (iffam);
284 	}
285 	return (NULL);
286 }
287 
288 /*
289  * Find the first free unit number for a new interface.
290  * Increase the size of the unit bitmap as necessary.
291  */
292 static __inline int
293 ng_iface_get_unit(int *unit)
294 {
295 	int index, bit;
296 
297 	mtx_lock(&ng_iface_mtx);
298 	for (index = 0; index < ng_iface_units_len
299 	    && ng_iface_units[index] == 0; index++);
300 	if (index == ng_iface_units_len) {		/* extend array */
301 		int i, *newarray, newlen;
302 
303 		newlen = (2 * ng_iface_units_len) + 4;
304 		MALLOC(newarray, int *, newlen * sizeof(*ng_iface_units),
305 		    M_NETGRAPH_IFACE, M_NOWAIT);
306 		if (newarray == NULL) {
307 			mtx_unlock(&ng_iface_mtx);
308 			return (ENOMEM);
309 		}
310 		bcopy(ng_iface_units, newarray,
311 		    ng_iface_units_len * sizeof(*ng_iface_units));
312 		for (i = ng_iface_units_len; i < newlen; i++)
313 			newarray[i] = ~0;
314 		if (ng_iface_units != NULL)
315 			FREE(ng_iface_units, M_NETGRAPH_IFACE);
316 		ng_iface_units = newarray;
317 		ng_iface_units_len = newlen;
318 	}
319 	bit = ffs(ng_iface_units[index]) - 1;
320 	KASSERT(bit >= 0 && bit <= UNITS_BITSPERWORD - 1,
321 	    ("%s: word=%d bit=%d", __func__, ng_iface_units[index], bit));
322 	ng_iface_units[index] &= ~(1 << bit);
323 	*unit = (index * UNITS_BITSPERWORD) + bit;
324 	ng_units_in_use++;
325 	mtx_unlock(&ng_iface_mtx);
326 	return (0);
327 }
328 
329 /*
330  * Free a no longer needed unit number.
331  */
332 static __inline void
333 ng_iface_free_unit(int unit)
334 {
335 	int index, bit;
336 
337 	index = unit / UNITS_BITSPERWORD;
338 	bit = unit % UNITS_BITSPERWORD;
339 	mtx_lock(&ng_iface_mtx);
340 	KASSERT(index < ng_iface_units_len,
341 	    ("%s: unit=%d len=%d", __func__, unit, ng_iface_units_len));
342 	KASSERT((ng_iface_units[index] & (1 << bit)) == 0,
343 	    ("%s: unit=%d is free", __func__, unit));
344 	ng_iface_units[index] |= (1 << bit);
345 	/*
346 	 * XXX We could think about reducing the size of ng_iface_units[]
347 	 * XXX here if the last portion is all ones
348 	 * XXX At least free it if no more units.
349 	 * Needed if we are to eventually be able to unload.
350 	 */
351 	ng_units_in_use--;
352 	if (ng_units_in_use == 0) { /* XXX make SMP safe */
353 		FREE(ng_iface_units, M_NETGRAPH_IFACE);
354 		ng_iface_units_len = 0;
355 		ng_iface_units = NULL;
356 	}
357 	mtx_unlock(&ng_iface_mtx);
358 }
359 
360 /************************************************************************
361 			INTERFACE STUFF
362  ************************************************************************/
363 
364 /*
365  * Process an ioctl for the virtual interface
366  */
367 static int
368 ng_iface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
369 {
370 	struct ifreq *const ifr = (struct ifreq *) data;
371 	int s, error = 0;
372 
373 #ifdef DEBUG
374 	ng_iface_print_ioctl(ifp, command, data);
375 #endif
376 	s = splimp();
377 	switch (command) {
378 
379 	/* These two are mostly handled at a higher layer */
380 	case SIOCSIFADDR:
381 		ifp->if_flags |= (IFF_UP | IFF_RUNNING);
382 		ifp->if_flags &= ~(IFF_OACTIVE);
383 		break;
384 	case SIOCGIFADDR:
385 		break;
386 
387 	/* Set flags */
388 	case SIOCSIFFLAGS:
389 		/*
390 		 * If the interface is marked up and stopped, then start it.
391 		 * If it is marked down and running, then stop it.
392 		 */
393 		if (ifr->ifr_flags & IFF_UP) {
394 			if (!(ifp->if_flags & IFF_RUNNING)) {
395 				ifp->if_flags &= ~(IFF_OACTIVE);
396 				ifp->if_flags |= IFF_RUNNING;
397 			}
398 		} else {
399 			if (ifp->if_flags & IFF_RUNNING)
400 				ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
401 		}
402 		break;
403 
404 	/* Set the interface MTU */
405 	case SIOCSIFMTU:
406 		if (ifr->ifr_mtu > NG_IFACE_MTU_MAX
407 		    || ifr->ifr_mtu < NG_IFACE_MTU_MIN)
408 			error = EINVAL;
409 		else
410 			ifp->if_mtu = ifr->ifr_mtu;
411 		break;
412 
413 	/* Stuff that's not supported */
414 	case SIOCADDMULTI:
415 	case SIOCDELMULTI:
416 		error = 0;
417 		break;
418 	case SIOCSIFPHYS:
419 		error = EOPNOTSUPP;
420 		break;
421 
422 	default:
423 		error = EINVAL;
424 		break;
425 	}
426 	(void) splx(s);
427 	return (error);
428 }
429 
430 /*
431  * This routine is called to deliver a packet out the interface.
432  * We simply look at the address family and relay the packet to
433  * the corresponding hook, if it exists and is connected.
434  */
435 
436 static int
437 ng_iface_output(struct ifnet *ifp, struct mbuf *m,
438 		struct sockaddr *dst, struct rtentry *rt0)
439 {
440 	const priv_p priv = (priv_p) ifp->if_softc;
441 	const iffam_p iffam = get_iffam_from_af(dst->sa_family);
442 	int len, error = 0;
443 
444 	/* Check interface flags */
445 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
446 		m_freem(m);
447 		return (ENETDOWN);
448 	}
449 
450 	/* BPF writes need to be handled specially */
451 	if (dst->sa_family == AF_UNSPEC) {
452 		if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
453 			return (ENOBUFS);
454 		dst->sa_family = (sa_family_t)*mtod(m, int32_t *);
455 		m->m_data += 4;
456 		m->m_len -= 4;
457 		m->m_pkthdr.len -= 4;
458 	}
459 
460 	/* Berkeley packet filter */
461 	ng_iface_bpftap(ifp, m, dst->sa_family);
462 
463 	/* Check address family to determine hook (if known) */
464 	if (iffam == NULL) {
465 		m_freem(m);
466 		log(LOG_WARNING, "%s: can't handle af%d\n",
467 		       ifp->if_xname, (int)dst->sa_family);
468 		return (EAFNOSUPPORT);
469 	}
470 
471 	/* Copy length before the mbuf gets invalidated */
472 	len = m->m_pkthdr.len;
473 
474 	/* Send packet; if hook is not connected, mbuf will get freed. */
475 	NG_SEND_DATA_ONLY(error, *get_hook_from_iffam(priv, iffam), m);
476 
477 	/* Update stats */
478 	if (error == 0) {
479 		ifp->if_obytes += len;
480 		ifp->if_opackets++;
481 	}
482 	return (error);
483 }
484 
485 /*
486  * This routine should never be called
487  */
488 
489 static void
490 ng_iface_start(struct ifnet *ifp)
491 {
492 	if_printf(ifp, "%s called?", __func__);
493 }
494 
495 /*
496  * Flash a packet by the BPF (requires prepending 4 byte AF header)
497  * Note the phoney mbuf; this is OK because BPF treats it read-only.
498  */
499 static void
500 ng_iface_bpftap(struct ifnet *ifp, struct mbuf *m, sa_family_t family)
501 {
502 	KASSERT(family != AF_UNSPEC, ("%s: family=AF_UNSPEC", __func__));
503 	if (ifp->if_bpf != NULL) {
504 		int32_t family4 = (int32_t)family;
505 		bpf_mtap2(ifp->if_bpf, &family4, sizeof(family4), m);
506 	}
507 }
508 
509 #ifdef DEBUG
510 /*
511  * Display an ioctl to the virtual interface
512  */
513 
514 static void
515 ng_iface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
516 {
517 	char   *str;
518 
519 	switch (command & IOC_DIRMASK) {
520 	case IOC_VOID:
521 		str = "IO";
522 		break;
523 	case IOC_OUT:
524 		str = "IOR";
525 		break;
526 	case IOC_IN:
527 		str = "IOW";
528 		break;
529 	case IOC_INOUT:
530 		str = "IORW";
531 		break;
532 	default:
533 		str = "IO??";
534 	}
535 	log(LOG_DEBUG, "%s: %s('%c', %d, char[%d])\n",
536 	       ifp->if_xname,
537 	       str,
538 	       IOCGROUP(command),
539 	       command & 0xff,
540 	       IOCPARM_LEN(command));
541 }
542 #endif /* DEBUG */
543 
544 /************************************************************************
545 			NETGRAPH NODE STUFF
546  ************************************************************************/
547 
548 /*
549  * Constructor for a node
550  */
551 static int
552 ng_iface_constructor(node_p node)
553 {
554 	char ifname[NG_IFACE_IFACE_NAME_MAX + 1];
555 	struct ifnet *ifp;
556 	priv_p priv;
557 	int error = 0;
558 
559 	/* Allocate node and interface private structures */
560 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
561 	if (priv == NULL)
562 		return (ENOMEM);
563 	MALLOC(ifp, struct ifnet *, sizeof(*ifp), M_NETGRAPH_IFACE, M_NOWAIT|M_ZERO);
564 	if (ifp == NULL) {
565 		FREE(priv, M_NETGRAPH_IFACE);
566 		return (ENOMEM);
567 	}
568 
569 	/* Link them together */
570 	ifp->if_softc = priv;
571 	priv->ifp = ifp;
572 
573 	/* Get an interface unit number */
574 	if ((error = ng_iface_get_unit(&priv->unit)) != 0) {
575 		FREE(ifp, M_NETGRAPH_IFACE);
576 		FREE(priv, M_NETGRAPH_IFACE);
577 		return (error);
578 	}
579 
580 	/* Link together node and private info */
581 	NG_NODE_SET_PRIVATE(node, priv);
582 	priv->node = node;
583 
584 	/* Initialize interface structure */
585 	if_initname(ifp, NG_IFACE_IFACE_NAME, priv->unit);
586 	ifp->if_output = ng_iface_output;
587 	ifp->if_start = ng_iface_start;
588 	ifp->if_ioctl = ng_iface_ioctl;
589 	ifp->if_watchdog = NULL;
590 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
591 	ifp->if_mtu = NG_IFACE_MTU_DEFAULT;
592 	ifp->if_flags = (IFF_SIMPLEX|IFF_POINTOPOINT|IFF_NOARP|IFF_MULTICAST);
593 	ifp->if_type = IFT_PROPVIRTUAL;		/* XXX */
594 	ifp->if_addrlen = 0;			/* XXX */
595 	ifp->if_hdrlen = 0;			/* XXX */
596 	ifp->if_baudrate = 64000;		/* XXX */
597 	TAILQ_INIT(&ifp->if_addrhead);
598 
599 	/* Give this node the same name as the interface (if possible) */
600 	bzero(ifname, sizeof(ifname));
601 	strlcpy(ifname, ifp->if_xname, sizeof(ifname));
602 	if (ng_name_node(node, ifname) != 0)
603 		log(LOG_WARNING, "%s: can't acquire netgraph name\n", ifname);
604 
605 	/* Attach the interface */
606 	if_attach(ifp);
607 	bpfattach(ifp, DLT_NULL, sizeof(u_int));
608 
609 	/* Done */
610 	return (0);
611 }
612 
613 /*
614  * Give our ok for a hook to be added
615  */
616 static int
617 ng_iface_newhook(node_p node, hook_p hook, const char *name)
618 {
619 	const iffam_p iffam = get_iffam_from_name(name);
620 	hook_p *hookptr;
621 
622 	if (iffam == NULL)
623 		return (EPFNOSUPPORT);
624 	hookptr = get_hook_from_iffam(NG_NODE_PRIVATE(node), iffam);
625 	if (*hookptr != NULL)
626 		return (EISCONN);
627 	*hookptr = hook;
628 	return (0);
629 }
630 
631 /*
632  * Receive a control message
633  */
634 static int
635 ng_iface_rcvmsg(node_p node, item_p item, hook_p lasthook)
636 {
637 	const priv_p priv = NG_NODE_PRIVATE(node);
638 	struct ifnet *const ifp = priv->ifp;
639 	struct ng_mesg *resp = NULL;
640 	int error = 0;
641 	struct ng_mesg *msg;
642 
643 	NGI_GET_MSG(item, msg);
644 	switch (msg->header.typecookie) {
645 	case NGM_IFACE_COOKIE:
646 		switch (msg->header.cmd) {
647 		case NGM_IFACE_GET_IFNAME:
648 		    {
649 			struct ng_iface_ifname *arg;
650 
651 			NG_MKRESPONSE(resp, msg, sizeof(*arg), M_NOWAIT);
652 			if (resp == NULL) {
653 				error = ENOMEM;
654 				break;
655 			}
656 			arg = (struct ng_iface_ifname *)resp->data;
657 			strlcpy(arg->ngif_name, ifp->if_xname,
658 			    sizeof(arg->ngif_name));
659 			break;
660 		    }
661 
662 		case NGM_IFACE_POINT2POINT:
663 		case NGM_IFACE_BROADCAST:
664 		    {
665 
666 			/* Deny request if interface is UP */
667 			if ((ifp->if_flags & IFF_UP) != 0)
668 				return (EBUSY);
669 
670 			/* Change flags */
671 			switch (msg->header.cmd) {
672 			case NGM_IFACE_POINT2POINT:
673 				ifp->if_flags |= IFF_POINTOPOINT;
674 				ifp->if_flags &= ~IFF_BROADCAST;
675 				break;
676 			case NGM_IFACE_BROADCAST:
677 				ifp->if_flags &= ~IFF_POINTOPOINT;
678 				ifp->if_flags |= IFF_BROADCAST;
679 				break;
680 			}
681 			break;
682 		    }
683 
684 		case NGM_IFACE_GET_IFINDEX:
685 			NG_MKRESPONSE(resp, msg, sizeof(uint32_t), M_NOWAIT);
686 			if (resp == NULL) {
687 				error = ENOMEM;
688 				break;
689 			}
690 			*((uint32_t *)resp->data) = priv->ifp->if_index;
691 			break;
692 
693 		default:
694 			error = EINVAL;
695 			break;
696 		}
697 		break;
698 	case NGM_CISCO_COOKIE:
699 		switch (msg->header.cmd) {
700 		case NGM_CISCO_GET_IPADDR:	/* we understand this too */
701 		    {
702 			struct ifaddr *ifa;
703 
704 			/* Return the first configured IP address */
705 			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
706 				struct ng_cisco_ipaddr *ips;
707 
708 				if (ifa->ifa_addr->sa_family != AF_INET)
709 					continue;
710 				NG_MKRESPONSE(resp, msg, sizeof(ips), M_NOWAIT);
711 				if (resp == NULL) {
712 					error = ENOMEM;
713 					break;
714 				}
715 				ips = (struct ng_cisco_ipaddr *)resp->data;
716 				ips->ipaddr = ((struct sockaddr_in *)
717 						ifa->ifa_addr)->sin_addr;
718 				ips->netmask = ((struct sockaddr_in *)
719 						ifa->ifa_netmask)->sin_addr;
720 				break;
721 			}
722 
723 			/* No IP addresses on this interface? */
724 			if (ifa == NULL)
725 				error = EADDRNOTAVAIL;
726 			break;
727 		    }
728 		default:
729 			error = EINVAL;
730 			break;
731 		}
732 		break;
733 	default:
734 		error = EINVAL;
735 		break;
736 	}
737 	NG_RESPOND_MSG(error, node, item, resp);
738 	NG_FREE_MSG(msg);
739 	return (error);
740 }
741 
742 /*
743  * Recive data from a hook. Pass the packet to the correct input routine.
744  */
745 static int
746 ng_iface_rcvdata(hook_p hook, item_p item)
747 {
748 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
749 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
750 	struct ifnet *const ifp = priv->ifp;
751 	struct mbuf *m;
752 	int isr;
753 
754 	NGI_GET_M(item, m);
755 	NG_FREE_ITEM(item);
756 	/* Sanity checks */
757 	KASSERT(iffam != NULL, ("%s: iffam", __func__));
758 	M_ASSERTPKTHDR(m);
759 	if ((ifp->if_flags & IFF_UP) == 0) {
760 		NG_FREE_M(m);
761 		return (ENETDOWN);
762 	}
763 
764 	/* Update interface stats */
765 	ifp->if_ipackets++;
766 	ifp->if_ibytes += m->m_pkthdr.len;
767 
768 	/* Note receiving interface */
769 	m->m_pkthdr.rcvif = ifp;
770 
771 	/* Berkeley packet filter */
772 	ng_iface_bpftap(ifp, m, iffam->family);
773 
774 	/* Send packet */
775 	switch (iffam->family) {
776 #ifdef INET
777 	case AF_INET:
778 		isr = NETISR_IP;
779 		break;
780 #endif
781 #ifdef INET6
782 	case AF_INET6:
783 		isr = NETISR_IPV6;
784 		break;
785 #endif
786 #ifdef IPX
787 	case AF_IPX:
788 		isr = NETISR_IPX;
789 		break;
790 #endif
791 #ifdef NETATALK
792 	case AF_APPLETALK:
793 		isr = NETISR_ATALK2;
794 		break;
795 #endif
796 	default:
797 		m_freem(m);
798 		return (EAFNOSUPPORT);
799 	}
800 	/* First chunk of an mbuf contains good junk */
801 	if (harvest.point_to_point)
802 		random_harvest(m, 16, 3, 0, RANDOM_NET);
803 	netisr_dispatch(isr, m);
804 	return (0);
805 }
806 
807 /*
808  * Shutdown and remove the node and its associated interface.
809  */
810 static int
811 ng_iface_shutdown(node_p node)
812 {
813 	const priv_p priv = NG_NODE_PRIVATE(node);
814 
815 	bpfdetach(priv->ifp);
816 	if_detach(priv->ifp);
817 	FREE(priv->ifp, M_NETGRAPH_IFACE);
818 	priv->ifp = NULL;
819 	ng_iface_free_unit(priv->unit);
820 	FREE(priv, M_NETGRAPH_IFACE);
821 	NG_NODE_SET_PRIVATE(node, NULL);
822 	NG_NODE_UNREF(node);
823 	return (0);
824 }
825 
826 /*
827  * Hook disconnection. Note that we do *not* shutdown when all
828  * hooks have been disconnected.
829  */
830 static int
831 ng_iface_disconnect(hook_p hook)
832 {
833 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
834 	const iffam_p iffam = get_iffam_from_hook(priv, hook);
835 
836 	if (iffam == NULL)
837 		panic(__func__);
838 	*get_hook_from_iffam(priv, iffam) = NULL;
839 	return (0);
840 }
841 
842