xref: /netbsd-src/sys/net/if_gre.c (revision 627f7eb200a4419d89b531d55fccd2ee3ffdcde0)
1 /*	$NetBSD: if_gre.c,v 1.180 2021/02/14 19:33:29 roy Exp $ */
2 
3 /*
4  * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Heiko W.Rupp <hwr@pilhuhn.de>
9  *
10  * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
11  *
12  * GRE over UDP/IPv4/IPv6 sockets contributed by David Young <dyoung@NetBSD.org>
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
27  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  *
35  * This material is based upon work partially supported by NSF
36  * under Contract No. NSF CNS-0626584.
37  */
38 
39 /*
40  * Encapsulate L3 protocols into IP
41  * See RFC 1701 and 1702 for more details.
42  * If_gre is compatible with Cisco GRE tunnels, so you can
43  * have a NetBSD box as the other end of a tunnel interface of a Cisco
44  * router. See gre(4) for more details.
45  */
46 
47 #include <sys/cdefs.h>
48 __KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.180 2021/02/14 19:33:29 roy Exp $");
49 
50 #ifdef _KERNEL_OPT
51 #include "opt_atalk.h"
52 #include "opt_gre.h"
53 #include "opt_inet.h"
54 #include "opt_mpls.h"
55 #endif
56 
57 #include <sys/param.h>
58 #include <sys/file.h>
59 #include <sys/filedesc.h>
60 #include <sys/malloc.h>
61 #include <sys/mallocvar.h>
62 #include <sys/mbuf.h>
63 #include <sys/proc.h>
64 #include <sys/domain.h>
65 #include <sys/protosw.h>
66 #include <sys/socket.h>
67 #include <sys/socketvar.h>
68 #include <sys/ioctl.h>
69 #include <sys/queue.h>
70 #include <sys/intr.h>
71 #include <sys/systm.h>
72 #include <sys/sysctl.h>
73 #include <sys/kauth.h>
74 #include <sys/device.h>
75 #include <sys/module.h>
76 
77 #include <sys/kernel.h>
78 #include <sys/mutex.h>
79 #include <sys/condvar.h>
80 #include <sys/kthread.h>
81 
82 #include <sys/cpu.h>
83 
84 #include <net/ethertypes.h>
85 #include <net/if.h>
86 #include <net/if_types.h>
87 #include <net/netisr.h>
88 #include <net/route.h>
89 #include <sys/device.h>
90 #include <sys/module.h>
91 #include <sys/atomic.h>
92 
93 #include <netinet/in_systm.h>
94 #include <netinet/in.h>
95 #include <netinet/ip.h> /* we always need this for sizeof(struct ip) */
96 
97 #ifdef INET
98 #include <netinet/in_var.h>
99 #include <netinet/ip_var.h>
100 #endif
101 
102 #ifdef INET6
103 #include <netinet6/in6_var.h>
104 #endif
105 
106 #ifdef MPLS
107 #include <netmpls/mpls.h>
108 #include <netmpls/mpls_var.h>
109 #endif
110 
111 #ifdef NETATALK
112 #include <netatalk/at.h>
113 #include <netatalk/at_var.h>
114 #include <netatalk/at_extern.h>
115 #endif
116 
117 #include <sys/time.h>
118 #include <net/bpf.h>
119 
120 #include <net/if_gre.h>
121 
122 #include "ioconf.h"
123 
124 /*
125  * It is not easy to calculate the right value for a GRE MTU.
126  * We leave this task to the admin and use the same default that
127  * other vendors use.
128  */
129 #define GREMTU 1476
130 
131 #ifdef GRE_DEBUG
132 int gre_debug = 0;
133 #define	GRE_DPRINTF(__sc, ...)						\
134 	do {								\
135 		if (__predict_false(gre_debug ||			\
136 		    ((__sc)->sc_if.if_flags & IFF_DEBUG) != 0)) {	\
137 			printf("%s.%d: ", __func__, __LINE__);		\
138 			printf(__VA_ARGS__);				\
139 		}							\
140 	} while (/*CONSTCOND*/0)
141 #else
142 #define	GRE_DPRINTF(__sc, __fmt, ...)	do { } while (/*CONSTCOND*/0)
143 #endif /* GRE_DEBUG */
144 
145 CTASSERT(sizeof(struct gre_h) == 4);
146 
147 int ip_gre_ttl = GRE_TTL;
148 
149 static u_int gre_count;
150 
151 static int gre_clone_create(struct if_clone *, int);
152 static int gre_clone_destroy(struct ifnet *);
153 
154 static struct if_clone gre_cloner =
155     IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy);
156 
157 static int gre_input(struct gre_softc *, struct mbuf *, const struct gre_h *);
158 static bool gre_is_nullconf(const struct gre_soparm *);
159 static int gre_output(struct ifnet *, struct mbuf *,
160 			   const struct sockaddr *, const struct rtentry *);
161 static int gre_ioctl(struct ifnet *, u_long, void *);
162 static int gre_getsockname(struct socket *, struct sockaddr *);
163 static int gre_getpeername(struct socket *, struct sockaddr *);
164 static int gre_getnames(struct socket *, struct lwp *,
165     struct sockaddr_storage *, struct sockaddr_storage *);
166 static void gre_clearconf(struct gre_soparm *, bool);
167 static int gre_soreceive(struct socket *, struct mbuf **);
168 static int gre_sosend(struct socket *, struct mbuf *);
169 static struct socket *gre_reconf(struct gre_softc *, const struct gre_soparm *);
170 
171 static bool gre_fp_send(struct gre_softc *, enum gre_msg, file_t *);
172 static bool gre_fp_recv(struct gre_softc *);
173 static void gre_fp_recvloop(void *);
174 
175 static void
176 gre_bufq_init(struct gre_bufq *bq, size_t len0)
177 {
178 	memset(bq, 0, sizeof(*bq));
179 	bq->bq_q = pcq_create(len0, KM_SLEEP);
180 	KASSERT(bq->bq_q != NULL);
181 }
182 
183 static struct mbuf *
184 gre_bufq_dequeue(struct gre_bufq *bq)
185 {
186 	return pcq_get(bq->bq_q);
187 }
188 
189 static void
190 gre_bufq_purge(struct gre_bufq *bq)
191 {
192 	struct mbuf *m;
193 
194 	while ((m = gre_bufq_dequeue(bq)) != NULL)
195 		m_freem(m);
196 }
197 
198 static void
199 gre_bufq_destroy(struct gre_bufq *bq)
200 {
201 	gre_bufq_purge(bq);
202 	pcq_destroy(bq->bq_q);
203 }
204 
205 static int
206 gre_bufq_enqueue(struct gre_bufq *bq, struct mbuf *m)
207 {
208 	KASSERT(bq->bq_q != NULL);
209 
210 	if (!pcq_put(bq->bq_q, m)) {
211 		bq->bq_drops++;
212 		return ENOBUFS;
213 	}
214 	return 0;
215 }
216 
217 static void
218 greintr(void *arg)
219 {
220 	struct gre_softc *sc = (struct gre_softc *)arg;
221 	struct socket *so = sc->sc_soparm.sp_so;
222 	int rc;
223 	struct mbuf *m;
224 
225 	KASSERT(so != NULL);
226 
227 	sc->sc_send_ev.ev_count++;
228 	GRE_DPRINTF(sc, "enter\n");
229 	while ((m = gre_bufq_dequeue(&sc->sc_snd)) != NULL) {
230 		/* XXX handle ENOBUFS? */
231 		if ((rc = gre_sosend(so, m)) != 0)
232 			GRE_DPRINTF(sc, "gre_sosend failed %d\n", rc);
233 	}
234 }
235 
236 /* Caller must hold sc->sc_mtx. */
237 static void
238 gre_fp_wait(struct gre_softc *sc)
239 {
240 	sc->sc_fp_waiters++;
241 	cv_wait(&sc->sc_fp_condvar, &sc->sc_mtx);
242 	sc->sc_fp_waiters--;
243 }
244 
245 static void
246 gre_evcnt_detach(struct gre_softc *sc)
247 {
248 	evcnt_detach(&sc->sc_recv_ev);
249 	evcnt_detach(&sc->sc_block_ev);
250 	evcnt_detach(&sc->sc_error_ev);
251 	evcnt_detach(&sc->sc_pullup_ev);
252 	evcnt_detach(&sc->sc_unsupp_ev);
253 
254 	evcnt_detach(&sc->sc_send_ev);
255 	evcnt_detach(&sc->sc_oflow_ev);
256 }
257 
258 static void
259 gre_evcnt_attach(struct gre_softc *sc)
260 {
261 	evcnt_attach_dynamic(&sc->sc_recv_ev, EVCNT_TYPE_MISC,
262 	    NULL, sc->sc_if.if_xname, "recv");
263 	evcnt_attach_dynamic(&sc->sc_block_ev, EVCNT_TYPE_MISC,
264 	    &sc->sc_recv_ev, sc->sc_if.if_xname, "would block");
265 	evcnt_attach_dynamic(&sc->sc_error_ev, EVCNT_TYPE_MISC,
266 	    &sc->sc_recv_ev, sc->sc_if.if_xname, "error");
267 	evcnt_attach_dynamic(&sc->sc_pullup_ev, EVCNT_TYPE_MISC,
268 	    &sc->sc_recv_ev, sc->sc_if.if_xname, "pullup failed");
269 	evcnt_attach_dynamic(&sc->sc_unsupp_ev, EVCNT_TYPE_MISC,
270 	    &sc->sc_recv_ev, sc->sc_if.if_xname, "unsupported");
271 
272 	evcnt_attach_dynamic(&sc->sc_send_ev, EVCNT_TYPE_MISC,
273 	    NULL, sc->sc_if.if_xname, "send");
274 	evcnt_attach_dynamic(&sc->sc_oflow_ev, EVCNT_TYPE_MISC,
275 	    &sc->sc_send_ev, sc->sc_if.if_xname, "overflow");
276 }
277 
278 static int
279 gre_clone_create(struct if_clone *ifc, int unit)
280 {
281 	int rc;
282 	struct gre_softc *sc;
283 	struct gre_soparm *sp;
284 	const struct sockaddr *any;
285 
286 	if ((any = sockaddr_any_by_family(AF_INET)) == NULL &&
287 	    (any = sockaddr_any_by_family(AF_INET6)) == NULL)
288 		goto fail0;
289 
290 	sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
291 	mutex_init(&sc->sc_mtx, MUTEX_DRIVER, IPL_SOFTNET);
292 	cv_init(&sc->sc_condvar, "gre wait");
293 	cv_init(&sc->sc_fp_condvar, "gre fp");
294 
295 	if_initname(&sc->sc_if, ifc->ifc_name, unit);
296 	sc->sc_if.if_softc = sc;
297 	sc->sc_if.if_type = IFT_TUNNEL;
298 	sc->sc_if.if_addrlen = 0;
299 	sc->sc_if.if_hdrlen = sizeof(struct ip) + sizeof(struct gre_h);
300 	sc->sc_if.if_dlt = DLT_NULL;
301 	sc->sc_if.if_mtu = GREMTU;
302 	sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
303 	sc->sc_if.if_output = gre_output;
304 	sc->sc_if.if_ioctl = gre_ioctl;
305 	sp = &sc->sc_soparm;
306 	sockaddr_copy(sstosa(&sp->sp_dst), sizeof(sp->sp_dst), any);
307 	sockaddr_copy(sstosa(&sp->sp_src), sizeof(sp->sp_src), any);
308 	sp->sp_proto = IPPROTO_GRE;
309 	sp->sp_type = SOCK_RAW;
310 
311 	sc->sc_fd = -1;
312 
313 	rc = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, gre_fp_recvloop, sc,
314 	    NULL, "%s", sc->sc_if.if_xname);
315 	if (rc)
316 		goto fail1;
317 
318 	gre_evcnt_attach(sc);
319 
320 	gre_bufq_init(&sc->sc_snd, 17);
321 	sc->sc_if.if_flags |= IFF_LINK0;
322 	if_attach(&sc->sc_if);
323 	if_alloc_sadl(&sc->sc_if);
324 	bpf_attach(&sc->sc_if, DLT_NULL, sizeof(uint32_t));
325 	atomic_inc_uint(&gre_count);
326 	return 0;
327 
328 fail1:
329 	cv_destroy(&sc->sc_fp_condvar);
330 	cv_destroy(&sc->sc_condvar);
331 	mutex_destroy(&sc->sc_mtx);
332 	free(sc, M_DEVBUF);
333 
334 fail0:
335 	return -1;
336 }
337 
338 static int
339 gre_clone_destroy(struct ifnet *ifp)
340 {
341 	int s;
342 	struct gre_softc *sc = ifp->if_softc;
343 
344 	GRE_DPRINTF(sc, "\n");
345 
346 	bpf_detach(ifp);
347 	s = splnet();
348 	if_detach(ifp);
349 
350 	GRE_DPRINTF(sc, "\n");
351 	/* Note that we must not hold the mutex while we call gre_reconf(). */
352 	gre_reconf(sc, NULL);
353 
354 	mutex_enter(&sc->sc_mtx);
355 	sc->sc_msg = GRE_M_STOP;
356 	cv_signal(&sc->sc_fp_condvar);
357 	while (sc->sc_fp_waiters > 0)
358 		cv_wait(&sc->sc_fp_condvar, &sc->sc_mtx);
359 	mutex_exit(&sc->sc_mtx);
360 
361 	splx(s);
362 
363 	cv_destroy(&sc->sc_condvar);
364 	cv_destroy(&sc->sc_fp_condvar);
365 	mutex_destroy(&sc->sc_mtx);
366 	gre_bufq_destroy(&sc->sc_snd);
367 	gre_evcnt_detach(sc);
368 	free(sc, M_DEVBUF);
369 
370 	atomic_dec_uint(&gre_count);
371 	return 0;
372 }
373 
374 static void
375 gre_receive(struct socket *so, void *arg, int events, int waitflag)
376 {
377 	struct gre_softc *sc = (struct gre_softc *)arg;
378 	int rc;
379 	struct gre_h gh;
380 	struct mbuf *m;
381 
382 	GRE_DPRINTF(sc, "enter\n");
383 
384 	sc->sc_recv_ev.ev_count++;
385 
386 	rc = gre_soreceive(so, &m);
387 	/* TBD Back off if ECONNREFUSED (indicates
388 	 * ICMP Port Unreachable)?
389 	 */
390 	if (rc == EWOULDBLOCK) {
391 		GRE_DPRINTF(sc, "EWOULDBLOCK\n");
392 		sc->sc_block_ev.ev_count++;
393 		return;
394 	} else if (rc != 0 || m == NULL) {
395 		GRE_DPRINTF(sc, "%s: rc %d m %p\n",
396 		    sc->sc_if.if_xname, rc, (void *)m);
397 		sc->sc_error_ev.ev_count++;
398 		return;
399 	}
400 
401 	if (__predict_false(m->m_len < sizeof(gh))) {
402 		if ((m = m_pullup(m, sizeof(gh))) == NULL) {
403 			GRE_DPRINTF(sc, "m_pullup failed\n");
404 			sc->sc_pullup_ev.ev_count++;
405 			return;
406 		}
407 	}
408 	memcpy(&gh, mtod(m, void *), sizeof(gh));
409 
410 	if (gre_input(sc, m, &gh) == 0) {
411 		sc->sc_unsupp_ev.ev_count++;
412 		GRE_DPRINTF(sc, "dropping unsupported\n");
413 		m_freem(m);
414 	}
415 }
416 
417 static void
418 gre_upcall_add(struct socket *so, void *arg)
419 {
420 	/* XXX What if the kernel already set an upcall? */
421 	KASSERT((so->so_rcv.sb_flags & SB_UPCALL) == 0);
422 	so->so_upcallarg = arg;
423 	so->so_upcall = gre_receive;
424 	so->so_rcv.sb_flags |= SB_UPCALL;
425 }
426 
427 static void
428 gre_upcall_remove(struct socket *so)
429 {
430 	so->so_rcv.sb_flags &= ~SB_UPCALL;
431 	so->so_upcallarg = NULL;
432 	so->so_upcall = NULL;
433 }
434 
435 static int
436 gre_socreate(struct gre_softc *sc, const struct gre_soparm *sp, int *fdout)
437 {
438 	int fd, rc;
439 	struct socket *so;
440 	struct sockaddr_big sbig;
441 	sa_family_t af;
442 	int val;
443 
444 	GRE_DPRINTF(sc, "enter\n");
445 
446 	af = sp->sp_src.ss_family;
447 	rc = fsocreate(af, NULL, sp->sp_type, sp->sp_proto, &fd);
448 	if (rc != 0) {
449 		GRE_DPRINTF(sc, "fsocreate failed\n");
450 		return rc;
451 	}
452 
453 	if ((rc = fd_getsock(fd, &so)) != 0)
454 		return rc;
455 
456 	memcpy(&sbig, &sp->sp_src, sizeof(sp->sp_src));
457 	if ((rc = sobind(so, (struct sockaddr *)&sbig, curlwp)) != 0) {
458 		GRE_DPRINTF(sc, "sobind failed\n");
459 		goto out;
460 	}
461 
462 	memcpy(&sbig, &sp->sp_dst, sizeof(sp->sp_dst));
463 	solock(so);
464 	if ((rc = soconnect(so, (struct sockaddr *)&sbig, curlwp)) != 0) {
465 		GRE_DPRINTF(sc, "soconnect failed\n");
466 		sounlock(so);
467 		goto out;
468 	}
469 	sounlock(so);
470 
471 	/* XXX convert to a (new) SOL_SOCKET call */
472   	KASSERT(so->so_proto != NULL);
473  	rc = so_setsockopt(curlwp, so, IPPROTO_IP, IP_TTL,
474 	    &ip_gre_ttl, sizeof(ip_gre_ttl));
475   	if (rc != 0) {
476  		GRE_DPRINTF(sc, "so_setsockopt ttl failed\n");
477   		rc = 0;
478   	}
479 
480  	val = 1;
481  	rc = so_setsockopt(curlwp, so, SOL_SOCKET, SO_NOHEADER,
482 	    &val, sizeof(val));
483   	if (rc != 0) {
484  		GRE_DPRINTF(sc, "so_setsockopt SO_NOHEADER failed\n");
485 		rc = 0;
486 	}
487 out:
488 	if (rc != 0)
489 		fd_close(fd);
490 	else  {
491 		fd_putfile(fd);
492 		*fdout = fd;
493 	}
494 
495 	return rc;
496 }
497 
498 static int
499 gre_sosend(struct socket *so, struct mbuf *top)
500 {
501 	struct proc	*p;
502 	long		space, resid;
503 	int		error;
504 	struct lwp * const l = curlwp;
505 
506 	p = l->l_proc;
507 
508 	resid = top->m_pkthdr.len;
509 	if (p)
510 		l->l_ru.ru_msgsnd++;
511 #define	snderr(errno)	{ error = errno; goto release; }
512 
513 	solock(so);
514 	if ((error = sblock(&so->so_snd, M_NOWAIT)) != 0)
515 		goto out;
516 	if (so->so_state & SS_CANTSENDMORE)
517 		snderr(EPIPE);
518 	if (so->so_error) {
519 		error = so->so_error;
520 		so->so_error = 0;
521 		goto release;
522 	}
523 	if ((so->so_state & SS_ISCONNECTED) == 0) {
524 		if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
525 			snderr(ENOTCONN);
526 		} else {
527 			snderr(EDESTADDRREQ);
528 		}
529 	}
530 	space = sbspace(&so->so_snd);
531 	if (resid > so->so_snd.sb_hiwat)
532 		snderr(EMSGSIZE);
533 	if (space < resid)
534 		snderr(EWOULDBLOCK);
535 	/*
536 	 * Data is prepackaged in "top".
537 	 */
538 	if (so->so_state & SS_CANTSENDMORE)
539 		snderr(EPIPE);
540 	error = (*so->so_proto->pr_usrreqs->pr_send)(so,
541 	    top, NULL, NULL, l);
542 	top = NULL;
543  release:
544 	sbunlock(&so->so_snd);
545  out:
546  	sounlock(so);
547 	if (top != NULL)
548 		m_freem(top);
549 	return error;
550 }
551 
552 /* This is a stripped-down version of soreceive() that will never
553  * block.  It will support SOCK_DGRAM sockets.  It may also support
554  * SOCK_SEQPACKET sockets.
555  */
556 static int
557 gre_soreceive(struct socket *so, struct mbuf **mp0)
558 {
559 	struct mbuf *m, **mp;
560 	int flags, len, error, type;
561 	const struct protosw	*pr;
562 	struct mbuf *nextrecord;
563 
564 	KASSERT(mp0 != NULL);
565 
566 	flags = MSG_DONTWAIT;
567 	pr = so->so_proto;
568 	mp = mp0;
569 	type = 0;
570 
571 	*mp = NULL;
572 
573 	KASSERT(pr->pr_flags & PR_ATOMIC);
574  restart:
575 	if ((error = sblock(&so->so_rcv, M_NOWAIT)) != 0) {
576 		return error;
577 	}
578 	m = so->so_rcv.sb_mb;
579 	/*
580 	 * If we have less data than requested, do not block awaiting more.
581 	 */
582 	if (m == NULL) {
583 #ifdef DIAGNOSTIC
584 		if (so->so_rcv.sb_cc)
585 			panic("receive 1");
586 #endif
587 		if (so->so_error) {
588 			error = so->so_error;
589 			so->so_error = 0;
590 		} else if (so->so_state & SS_CANTRCVMORE)
591 			;
592 		else if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0
593 		      && (so->so_proto->pr_flags & PR_CONNREQUIRED))
594 			error = ENOTCONN;
595 		else
596 			error = EWOULDBLOCK;
597 		goto release;
598 	}
599 	/*
600 	 * On entry here, m points to the first record of the socket buffer.
601 	 * While we process the initial mbufs containing address and control
602 	 * info, we save a copy of m->m_nextpkt into nextrecord.
603 	 */
604 	if (curlwp != NULL)
605 		curlwp->l_ru.ru_msgrcv++;
606 	KASSERT(m == so->so_rcv.sb_mb);
607 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 1");
608 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 1");
609 	nextrecord = m->m_nextpkt;
610 	if (pr->pr_flags & PR_ADDR) {
611 #ifdef DIAGNOSTIC
612 		if (m->m_type != MT_SONAME)
613 			panic("receive 1a");
614 #endif
615 		sbfree(&so->so_rcv, m);
616 		m = so->so_rcv.sb_mb = m_free(m);
617 	}
618 	while (m != NULL && m->m_type == MT_CONTROL && error == 0) {
619 		sbfree(&so->so_rcv, m);
620 		/*
621 		 * Dispose of any SCM_RIGHTS message that went
622 		 * through the read path rather than recv.
623 		 */
624 		if (pr->pr_domain->dom_dispose &&
625 		    mtod(m, struct cmsghdr *)->cmsg_type == SCM_RIGHTS)
626 			(*pr->pr_domain->dom_dispose)(m);
627 		m = so->so_rcv.sb_mb = m_free(m);
628 	}
629 
630 	/*
631 	 * If m is non-NULL, we have some data to read.  From now on,
632 	 * make sure to keep sb_lastrecord consistent when working on
633 	 * the last packet on the chain (nextrecord == NULL) and we
634 	 * change m->m_nextpkt.
635 	 */
636 	if (m != NULL) {
637 		m->m_nextpkt = nextrecord;
638 		/*
639 		 * If nextrecord == NULL (this is a single chain),
640 		 * then sb_lastrecord may not be valid here if m
641 		 * was changed earlier.
642 		 */
643 		if (nextrecord == NULL) {
644 			KASSERT(so->so_rcv.sb_mb == m);
645 			so->so_rcv.sb_lastrecord = m;
646 		}
647 		type = m->m_type;
648 		if (type == MT_OOBDATA)
649 			flags |= MSG_OOB;
650 	} else {
651 		KASSERT(so->so_rcv.sb_mb == m);
652 		so->so_rcv.sb_mb = nextrecord;
653 		SB_EMPTY_FIXUP(&so->so_rcv);
654 	}
655 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 2");
656 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 2");
657 
658 	while (m != NULL) {
659 		if (m->m_type == MT_OOBDATA) {
660 			if (type != MT_OOBDATA)
661 				break;
662 		} else if (type == MT_OOBDATA)
663 			break;
664 #ifdef DIAGNOSTIC
665 		else if (m->m_type != MT_DATA && m->m_type != MT_HEADER)
666 			panic("receive 3");
667 #endif
668 		so->so_state &= ~SS_RCVATMARK;
669 		if (so->so_oobmark != 0 && so->so_oobmark < m->m_len)
670 			break;
671 		len = m->m_len;
672 		/*
673 		 * mp is set, just pass back the mbufs.
674 		 * Sockbuf must be consistent here (points to current mbuf,
675 		 * it points to next record) when we drop priority;
676 		 * we must note any additions to the sockbuf when we
677 		 * block interrupts again.
678 		 */
679 		if (m->m_flags & M_EOR)
680 			flags |= MSG_EOR;
681 		nextrecord = m->m_nextpkt;
682 		sbfree(&so->so_rcv, m);
683 		*mp = m;
684 		mp = &m->m_next;
685 		so->so_rcv.sb_mb = m = m->m_next;
686 		*mp = NULL;
687 		/*
688 		 * If m != NULL, we also know that
689 		 * so->so_rcv.sb_mb != NULL.
690 		 */
691 		KASSERT(so->so_rcv.sb_mb == m);
692 		if (m) {
693 			m->m_nextpkt = nextrecord;
694 			if (nextrecord == NULL)
695 				so->so_rcv.sb_lastrecord = m;
696 		} else {
697 			so->so_rcv.sb_mb = nextrecord;
698 			SB_EMPTY_FIXUP(&so->so_rcv);
699 		}
700 		SBLASTRECORDCHK(&so->so_rcv, "soreceive 3");
701 		SBLASTMBUFCHK(&so->so_rcv, "soreceive 3");
702 		if (so->so_oobmark) {
703 			so->so_oobmark -= len;
704 			if (so->so_oobmark == 0) {
705 				so->so_state |= SS_RCVATMARK;
706 				break;
707 			}
708 		}
709 		if (flags & MSG_EOR)
710 			break;
711 	}
712 
713 	if (m != NULL) {
714 		m_freem(*mp);
715 		*mp = NULL;
716 		error = ENOMEM;
717 		(void) sbdroprecord(&so->so_rcv);
718 	} else {
719 		/*
720 		 * First part is an inline SB_EMPTY_FIXUP().  Second
721 		 * part makes sure sb_lastrecord is up-to-date if
722 		 * there is still data in the socket buffer.
723 		 */
724 		so->so_rcv.sb_mb = nextrecord;
725 		if (so->so_rcv.sb_mb == NULL) {
726 			so->so_rcv.sb_mbtail = NULL;
727 			so->so_rcv.sb_lastrecord = NULL;
728 		} else if (nextrecord->m_nextpkt == NULL)
729 			so->so_rcv.sb_lastrecord = nextrecord;
730 	}
731 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 4");
732 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 4");
733 	if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
734 		(*pr->pr_usrreqs->pr_rcvd)(so, flags, curlwp);
735 	if (*mp0 == NULL && (flags & MSG_EOR) == 0 &&
736 	    (so->so_state & SS_CANTRCVMORE) == 0) {
737 		sbunlock(&so->so_rcv);
738 		goto restart;
739 	}
740 
741  release:
742 	sbunlock(&so->so_rcv);
743 	return error;
744 }
745 
746 static struct socket *
747 gre_reconf(struct gre_softc *sc, const struct gre_soparm *newsoparm)
748 {
749 	struct ifnet *ifp = &sc->sc_if;
750 
751 	GRE_DPRINTF(sc, "enter\n");
752 
753 shutdown:
754 	if (sc->sc_soparm.sp_so != NULL) {
755 		GRE_DPRINTF(sc, "\n");
756 		gre_upcall_remove(sc->sc_soparm.sp_so);
757 		softint_disestablish(sc->sc_si);
758 		sc->sc_si = NULL;
759 		gre_fp_send(sc, GRE_M_DELFP, NULL);
760 		gre_clearconf(&sc->sc_soparm, false);
761 	}
762 
763 	if (newsoparm != NULL) {
764 		GRE_DPRINTF(sc, "\n");
765 		sc->sc_soparm = *newsoparm;
766 		newsoparm = NULL;
767 	}
768 
769 	if (sc->sc_soparm.sp_so != NULL) {
770 		GRE_DPRINTF(sc, "\n");
771 		sc->sc_si = softint_establish(SOFTINT_NET, greintr, sc);
772 		gre_upcall_add(sc->sc_soparm.sp_so, sc);
773 		if ((ifp->if_flags & IFF_UP) == 0) {
774 			GRE_DPRINTF(sc, "down\n");
775 			goto shutdown;
776 		}
777 	}
778 
779 	GRE_DPRINTF(sc, "\n");
780 	if (sc->sc_soparm.sp_so != NULL)
781 		sc->sc_if.if_flags |= IFF_RUNNING;
782 	else {
783 		gre_bufq_purge(&sc->sc_snd);
784 		sc->sc_if.if_flags &= ~IFF_RUNNING;
785 	}
786 	return sc->sc_soparm.sp_so;
787 }
788 
789 static int
790 gre_input(struct gre_softc *sc, struct mbuf *m, const struct gre_h *gh)
791 {
792 	pktqueue_t *pktq = NULL;
793 	struct ifqueue *ifq = NULL;
794 	uint16_t flags;
795 	uint32_t af;		/* af passed to BPF tap */
796 	int isr = 0, s;
797 	int hlen;
798 
799 	if_statadd2(&sc->sc_if, if_ipackets, 1, if_ibytes, m->m_pkthdr.len);
800 
801 	hlen = sizeof(struct gre_h);
802 
803 	/* process GRE flags as packet can be of variable len */
804 	flags = ntohs(gh->flags);
805 
806 	/* Checksum & Offset are present */
807 	if ((flags & GRE_CP) | (flags & GRE_RP))
808 		hlen += 4;
809 	/* We don't support routing fields (variable length) */
810 	if (flags & GRE_RP) {
811 		if_statinc(&sc->sc_if, if_ierrors);
812 		return 0;
813 	}
814 	if (flags & GRE_KP)
815 		hlen += 4;
816 	if (flags & GRE_SP)
817 		hlen += 4;
818 
819 	switch (ntohs(gh->ptype)) { /* ethertypes */
820 #ifdef INET
821 	case ETHERTYPE_IP:
822 		pktq = ip_pktq;
823 		af = AF_INET;
824 		break;
825 #endif
826 #ifdef NETATALK
827 	case ETHERTYPE_ATALK:
828 		ifq = &atintrq1;
829 		isr = NETISR_ATALK;
830 		af = AF_APPLETALK;
831 		break;
832 #endif
833 #ifdef INET6
834 	case ETHERTYPE_IPV6:
835 		pktq = ip6_pktq;
836 		af = AF_INET6;
837 		break;
838 #endif
839 #ifdef MPLS
840 	case ETHERTYPE_MPLS:
841 		ifq = &mplsintrq;
842 		isr = NETISR_MPLS;
843 		af = AF_MPLS;
844 		break;
845 #endif
846 	default:	   /* others not yet supported */
847 		GRE_DPRINTF(sc, "unhandled ethertype 0x%04x\n",
848 		    ntohs(gh->ptype));
849 		if_statinc(&sc->sc_if, if_noproto);
850 		return 0;
851 	}
852 
853 	if (hlen > m->m_pkthdr.len) {
854 		m_freem(m);
855 		if_statinc(&sc->sc_if, if_ierrors);
856 		return 1;
857 	}
858 	m_adj(m, hlen);
859 
860 	bpf_mtap_af(&sc->sc_if, af, m, BPF_D_IN);
861 
862 	m_set_rcvif(m, &sc->sc_if);
863 
864 	if (__predict_true(pktq)) {
865 		if (__predict_false(!pktq_enqueue(pktq, m, 0))) {
866 			m_freem(m);
867 		}
868 		return 1;
869 	}
870 
871 	s = splnet();
872 	if (IF_QFULL(ifq)) {
873 		IF_DROP(ifq);
874 		m_freem(m);
875 	} else {
876 		IF_ENQUEUE(ifq, m);
877 	}
878 	/* we need schednetisr since the address family may change */
879 	schednetisr(isr);
880 	splx(s);
881 
882 	return 1;	/* packet is done, no further processing needed */
883 }
884 
885 /*
886  * The output routine. Takes a packet and encapsulates it in the protocol
887  * given by sc->sc_soparm.sp_proto. See also RFC 1701 and RFC 2004
888  */
889 static int
890 gre_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
891     const struct rtentry *rt)
892 {
893 	int error = 0;
894 	struct gre_softc *sc = ifp->if_softc;
895 	struct gre_h gh = { .flags = 0 };
896 	uint16_t etype = 0;
897 
898 	KASSERT((m->m_flags & M_PKTHDR) != 0);
899 
900 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
901 		m_freem(m);
902 		error = ENETDOWN;
903 		goto end;
904 	}
905 
906 	bpf_mtap_af(ifp, dst->sa_family, m, BPF_D_OUT);
907 
908 	m->m_flags &= ~(M_BCAST|M_MCAST);
909 
910 	GRE_DPRINTF(sc, "dst->sa_family=%d\n", dst->sa_family);
911 	switch (dst->sa_family) {
912 #ifdef INET
913 	case AF_INET:
914 		/*
915 		 * TBD Extract the IP ToS field and set the
916 		 * encapsulating protocol's ToS to suit.
917 		 */
918 		etype = htons(ETHERTYPE_IP);
919 		break;
920 #endif
921 #ifdef NETATALK
922 	case AF_APPLETALK:
923 		etype = htons(ETHERTYPE_ATALK);
924 		break;
925 #endif
926 #ifdef INET6
927 	case AF_INET6:
928 		etype = htons(ETHERTYPE_IPV6);
929 		break;
930 #endif
931 	default:
932 		IF_DROP(&ifp->if_snd);
933 		m_freem(m);
934 		error = EAFNOSUPPORT;
935 		goto end;
936 	}
937 
938 #ifdef MPLS
939 	if (rt != NULL && rt_gettag(rt) != NULL) {
940 		union mpls_shim msh;
941 		msh.s_addr = MPLS_GETSADDR(rt);
942 		if (msh.shim.label != MPLS_LABEL_IMPLNULL)
943 			etype = htons(ETHERTYPE_MPLS);
944 	}
945 #endif
946 
947 	M_PREPEND(m, sizeof(gh), M_DONTWAIT);
948 	if (m == NULL) {
949 		IF_DROP(&ifp->if_snd);
950 		error = ENOBUFS;
951 		goto end;
952 	}
953 
954 	gh.ptype = etype;
955 	memcpy(mtod(m, void *), &gh, sizeof(gh));
956 	/* XXX Need to handle IP ToS.  Look at how I handle IP TTL. */
957 
958 	if_statadd2(ifp, if_opackets, 1, if_obytes, m->m_pkthdr.len);
959 
960 	/* Clear checksum-offload flags. */
961 	m->m_pkthdr.csum_flags = 0;
962 	m->m_pkthdr.csum_data = 0;
963 
964 	/* send it off */
965 	if ((error = gre_bufq_enqueue(&sc->sc_snd, m)) != 0) {
966 		sc->sc_oflow_ev.ev_count++;
967 		m_freem(m);
968 	} else {
969 		kpreempt_disable();
970 		softint_schedule(sc->sc_si);
971 		kpreempt_enable();
972 	}
973 
974 end:
975 	if (error)
976 		if_statinc(ifp, if_oerrors);
977 	return error;
978 }
979 
980 static int
981 gre_getsockname(struct socket *so, struct sockaddr *nam)
982 {
983 	return (*so->so_proto->pr_usrreqs->pr_sockaddr)(so, nam);
984 }
985 
986 static int
987 gre_getpeername(struct socket *so, struct sockaddr *nam)
988 {
989 	return (*so->so_proto->pr_usrreqs->pr_peeraddr)(so, nam);
990 }
991 
992 static int
993 gre_getnames(struct socket *so, struct lwp *l, struct sockaddr_storage *src,
994     struct sockaddr_storage *dst)
995 {
996 	struct sockaddr_storage ss;
997 	int rc;
998 
999 	solock(so);
1000 	if ((rc = gre_getsockname(so, (struct sockaddr *)&ss)) != 0)
1001 		goto out;
1002 	*src = ss;
1003 
1004 	if ((rc = gre_getpeername(so, (struct sockaddr *)&ss)) != 0)
1005 		goto out;
1006 	*dst = ss;
1007 out:
1008 	sounlock(so);
1009 	return rc;
1010 }
1011 
1012 static void
1013 gre_fp_recvloop(void *arg)
1014 {
1015 	struct gre_softc *sc = arg;
1016 
1017 	mutex_enter(&sc->sc_mtx);
1018 	while (gre_fp_recv(sc))
1019 		;
1020 	mutex_exit(&sc->sc_mtx);
1021 	kthread_exit(0);
1022 }
1023 
1024 static bool
1025 gre_fp_recv(struct gre_softc *sc)
1026 {
1027 	int fd, ofd, rc;
1028 	file_t *fp;
1029 
1030 	fp = sc->sc_fp;
1031 	ofd = sc->sc_fd;
1032 	fd = -1;
1033 
1034 	switch (sc->sc_msg) {
1035 	case GRE_M_STOP:
1036 		cv_signal(&sc->sc_fp_condvar);
1037 		return false;
1038 	case GRE_M_SETFP:
1039 		mutex_exit(&sc->sc_mtx);
1040 		rc = fd_dup(fp, 0, &fd, 0);
1041 		mutex_enter(&sc->sc_mtx);
1042 		if (rc != 0) {
1043 			sc->sc_msg = GRE_M_ERR;
1044 			break;
1045 		}
1046 		/*FALLTHROUGH*/
1047 	case GRE_M_DELFP:
1048 		mutex_exit(&sc->sc_mtx);
1049 		if (ofd != -1 && fd_getfile(ofd) != NULL)
1050 			fd_close(ofd);
1051 		mutex_enter(&sc->sc_mtx);
1052 		sc->sc_fd = fd;
1053 		sc->sc_msg = GRE_M_OK;
1054 		break;
1055 	default:
1056 		gre_fp_wait(sc);
1057 		return true;
1058 	}
1059 	cv_signal(&sc->sc_fp_condvar);
1060 	return true;
1061 }
1062 
1063 static bool
1064 gre_fp_send(struct gre_softc *sc, enum gre_msg msg, file_t *fp)
1065 {
1066 	bool rc;
1067 
1068 	mutex_enter(&sc->sc_mtx);
1069 	while (sc->sc_msg != GRE_M_NONE)
1070 		gre_fp_wait(sc);
1071 	sc->sc_fp = fp;
1072 	sc->sc_msg = msg;
1073 	cv_signal(&sc->sc_fp_condvar);
1074 	while (sc->sc_msg != GRE_M_STOP && sc->sc_msg != GRE_M_OK &&
1075 	            sc->sc_msg != GRE_M_ERR)
1076 		gre_fp_wait(sc);
1077 	rc = (sc->sc_msg != GRE_M_ERR);
1078 	sc->sc_msg = GRE_M_NONE;
1079 	cv_signal(&sc->sc_fp_condvar);
1080 	mutex_exit(&sc->sc_mtx);
1081 	return rc;
1082 }
1083 
1084 static int
1085 gre_ssock(struct ifnet *ifp, struct gre_soparm *sp, int fd)
1086 {
1087 	int error = 0;
1088 	const struct protosw *pr;
1089 	file_t *fp;
1090 	struct gre_softc *sc = ifp->if_softc;
1091 	struct socket *so;
1092 	struct sockaddr_storage dst, src;
1093 
1094 	if ((fp = fd_getfile(fd)) == NULL)
1095 		return EBADF;
1096 	if (fp->f_type != DTYPE_SOCKET) {
1097 		fd_putfile(fd);
1098 		return ENOTSOCK;
1099 	}
1100 
1101 	GRE_DPRINTF(sc, "\n");
1102 
1103 	so = fp->f_socket;
1104 	pr = so->so_proto;
1105 
1106 	GRE_DPRINTF(sc, "type %d, proto %d\n", pr->pr_type, pr->pr_protocol);
1107 
1108 	if ((pr->pr_flags & PR_ATOMIC) == 0 ||
1109 	    (sp->sp_type != 0 && pr->pr_type != sp->sp_type) ||
1110 	    (sp->sp_proto != 0 && pr->pr_protocol != 0 &&
1111 	     pr->pr_protocol != sp->sp_proto)) {
1112 		error = EINVAL;
1113 		goto err;
1114 	}
1115 
1116 	GRE_DPRINTF(sc, "\n");
1117 
1118 	/* check address */
1119 	if ((error = gre_getnames(so, curlwp, &src, &dst)) != 0)
1120 		goto err;
1121 
1122 	GRE_DPRINTF(sc, "\n");
1123 
1124 	if (!gre_fp_send(sc, GRE_M_SETFP, fp)) {
1125 		error = EBUSY;
1126 		goto err;
1127 	}
1128 
1129 	GRE_DPRINTF(sc, "\n");
1130 
1131 	sp->sp_src = src;
1132 	sp->sp_dst = dst;
1133 
1134 	sp->sp_so = so;
1135 
1136 err:
1137 	fd_putfile(fd);
1138 	return error;
1139 }
1140 
1141 static bool
1142 sockaddr_is_anyaddr(const struct sockaddr *sa)
1143 {
1144 	socklen_t anylen, salen;
1145 	const void *anyaddr, *addr;
1146 
1147 	if ((anyaddr = sockaddr_anyaddr(sa, &anylen)) == NULL ||
1148 	    (addr = sockaddr_const_addr(sa, &salen)) == NULL)
1149 		return false;
1150 
1151 	if (salen > anylen)
1152 		return false;
1153 
1154 	return memcmp(anyaddr, addr, MIN(anylen, salen)) == 0;
1155 }
1156 
1157 static bool
1158 gre_is_nullconf(const struct gre_soparm *sp)
1159 {
1160 	return sockaddr_is_anyaddr(sstocsa(&sp->sp_src)) ||
1161 	       sockaddr_is_anyaddr(sstocsa(&sp->sp_dst));
1162 }
1163 
1164 static void
1165 gre_clearconf(struct gre_soparm *sp, bool force)
1166 {
1167 	if (sp->sp_bysock || force) {
1168 		sockaddr_copy(sstosa(&sp->sp_src), sizeof(sp->sp_src),
1169 		    sockaddr_any(sstosa(&sp->sp_src)));
1170 		sockaddr_copy(sstosa(&sp->sp_dst), sizeof(sp->sp_dst),
1171 		    sockaddr_any(sstosa(&sp->sp_dst)));
1172 		sp->sp_bysock = false;
1173 	}
1174 	sp->sp_so = NULL; /* XXX */
1175 }
1176 
1177 static int
1178 gre_ioctl(struct ifnet *ifp, const u_long cmd, void *data)
1179 {
1180 	struct ifreq *ifr;
1181 	struct ifaddr *ifa = (struct ifaddr *)data;
1182 	struct if_laddrreq *lifr = (struct if_laddrreq *)data;
1183 	struct gre_softc *sc = ifp->if_softc;
1184 	struct gre_soparm *sp;
1185 	int fd, error = 0, oproto, otype, s;
1186 	struct gre_soparm sp0;
1187 
1188 	ifr = data;
1189 
1190 	GRE_DPRINTF(sc, "cmd %lu\n", cmd);
1191 
1192 	switch (cmd) {
1193 	case GRESPROTO:
1194 	case GRESADDRD:
1195 	case GRESADDRS:
1196 	case GRESSOCK:
1197 	case GREDSOCK:
1198 		if (kauth_authorize_network(curlwp->l_cred,
1199 		    KAUTH_NETWORK_INTERFACE,
1200 		    KAUTH_REQ_NETWORK_INTERFACE_SETPRIV, ifp, (void *)cmd,
1201 		    NULL) != 0)
1202 			return EPERM;
1203 		break;
1204 	default:
1205 		break;
1206 	}
1207 
1208 	s = splnet();
1209 
1210 	sp0 = sc->sc_soparm;
1211 	sp0.sp_so = NULL;
1212 	sp = &sp0;
1213 
1214 	GRE_DPRINTF(sc, "\n");
1215 
1216 	switch (cmd) {
1217 	case SIOCINITIFADDR:
1218 		GRE_DPRINTF(sc, "\n");
1219 		if ((ifp->if_flags & IFF_UP) != 0)
1220 			break;
1221 		gre_clearconf(sp, false);
1222 		ifp->if_flags |= IFF_UP;
1223 		ifa->ifa_rtrequest = p2p_rtrequest;
1224 		goto mksocket;
1225 	case SIOCSIFFLAGS:
1226 		if ((error = ifioctl_common(ifp, cmd, data)) != 0)
1227 			break;
1228 		oproto = sp->sp_proto;
1229 		otype = sp->sp_type;
1230 		switch (ifr->ifr_flags & (IFF_LINK0|IFF_LINK2)) {
1231 		case IFF_LINK0|IFF_LINK2:
1232 			sp->sp_proto = IPPROTO_UDP;
1233 			sp->sp_type = SOCK_DGRAM;
1234 			break;
1235 		case IFF_LINK2:
1236 			sp->sp_proto = 0;
1237 			sp->sp_type = 0;
1238 			break;
1239 		case IFF_LINK0:
1240 			sp->sp_proto = IPPROTO_GRE;
1241 			sp->sp_type = SOCK_RAW;
1242 			break;
1243 		default:
1244 			GRE_DPRINTF(sc, "\n");
1245 			error = EINVAL;
1246 			goto out;
1247 		}
1248 		GRE_DPRINTF(sc, "\n");
1249 		gre_clearconf(sp, false);
1250 		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) ==
1251 		    (IFF_UP|IFF_RUNNING) &&
1252 		    (oproto == sp->sp_proto || sp->sp_proto == 0) &&
1253 		    (otype == sp->sp_type || sp->sp_type == 0))
1254 			break;
1255 		switch (sp->sp_proto) {
1256 		case IPPROTO_UDP:
1257 		case IPPROTO_GRE:
1258 			goto mksocket;
1259 		default:
1260 			break;
1261 		}
1262 		break;
1263 	case SIOCSIFMTU:
1264 		/* XXX determine MTU automatically by probing w/
1265 		 * XXX do-not-fragment packets?
1266 		 */
1267 		if (ifr->ifr_mtu < 576) {
1268 			error = EINVAL;
1269 			break;
1270 		}
1271 		/*FALLTHROUGH*/
1272 	case SIOCGIFMTU:
1273 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
1274 			error = 0;
1275 		break;
1276 	case SIOCADDMULTI:
1277 	case SIOCDELMULTI:
1278 		if (ifr == NULL) {
1279 			error = EAFNOSUPPORT;
1280 			break;
1281 		}
1282 		switch (ifreq_getaddr(cmd, ifr)->sa_family) {
1283 #ifdef INET
1284 		case AF_INET:
1285 			break;
1286 #endif
1287 #ifdef INET6
1288 		case AF_INET6:
1289 			break;
1290 #endif
1291 		default:
1292 			error = EAFNOSUPPORT;
1293 			break;
1294 		}
1295 		break;
1296 	case GRESPROTO:
1297 		gre_clearconf(sp, false);
1298 		oproto = sp->sp_proto;
1299 		otype = sp->sp_type;
1300 		sp->sp_proto = ifr->ifr_flags;
1301 		switch (sp->sp_proto) {
1302 		case IPPROTO_UDP:
1303 			ifp->if_flags |= IFF_LINK0|IFF_LINK2;
1304 			sp->sp_type = SOCK_DGRAM;
1305 			break;
1306 		case IPPROTO_GRE:
1307 			ifp->if_flags |= IFF_LINK0;
1308 			ifp->if_flags &= ~IFF_LINK2;
1309 			sp->sp_type = SOCK_RAW;
1310 			break;
1311 		case 0:
1312 			ifp->if_flags &= ~IFF_LINK0;
1313 			ifp->if_flags |= IFF_LINK2;
1314 			sp->sp_type = 0;
1315 			break;
1316 		default:
1317 			error = EPROTONOSUPPORT;
1318 			break;
1319 		}
1320 		if ((oproto == sp->sp_proto || sp->sp_proto == 0) &&
1321 		    (otype == sp->sp_type || sp->sp_type == 0))
1322 			break;
1323 		switch (sp->sp_proto) {
1324 		case IPPROTO_UDP:
1325 		case IPPROTO_GRE:
1326 			goto mksocket;
1327 		default:
1328 			break;
1329 		}
1330 		break;
1331 	case GREGPROTO:
1332 		ifr->ifr_flags = sp->sp_proto;
1333 		break;
1334 	case GRESADDRS:
1335 	case GRESADDRD:
1336 		gre_clearconf(sp, false);
1337 		/* set tunnel endpoints and mark interface as up */
1338 		switch (cmd) {
1339 		case GRESADDRS:
1340 			sockaddr_copy(sstosa(&sp->sp_src),
1341 			    sizeof(sp->sp_src), ifreq_getaddr(cmd, ifr));
1342 			break;
1343 		case GRESADDRD:
1344 			sockaddr_copy(sstosa(&sp->sp_dst),
1345 			    sizeof(sp->sp_dst), ifreq_getaddr(cmd, ifr));
1346 			break;
1347 		}
1348 	checkaddr:
1349 		if (sockaddr_any(sstosa(&sp->sp_src)) == NULL ||
1350 		    sockaddr_any(sstosa(&sp->sp_dst)) == NULL) {
1351 			error = EINVAL;
1352 			break;
1353 		}
1354 		/* let gre_socreate() check the rest */
1355 	mksocket:
1356 		GRE_DPRINTF(sc, "\n");
1357 		/* If we're administratively down, or the configuration
1358 		 * is empty, there's no use creating a socket.
1359 		 */
1360 		if ((ifp->if_flags & IFF_UP) == 0 || gre_is_nullconf(sp))
1361 			goto sendconf;
1362 
1363 		GRE_DPRINTF(sc, "\n");
1364 		fd = 0;
1365 		error = gre_socreate(sc, sp, &fd);
1366 		if (error != 0)
1367 			break;
1368 
1369 	setsock:
1370 		GRE_DPRINTF(sc, "\n");
1371 
1372 		error = gre_ssock(ifp, sp, fd);
1373 
1374 		if (cmd != GRESSOCK) {
1375 			GRE_DPRINTF(sc, "\n");
1376 			/* XXX v. dodgy */
1377 			if (fd_getfile(fd) != NULL)
1378 				fd_close(fd);
1379 		}
1380 
1381 		if (error == 0) {
1382 	sendconf:
1383 			GRE_DPRINTF(sc, "\n");
1384 			ifp->if_flags &= ~IFF_RUNNING;
1385 			gre_reconf(sc, sp);
1386 		}
1387 
1388 		break;
1389 	case GREGADDRS:
1390 		ifreq_setaddr(cmd, ifr, sstosa(&sp->sp_src));
1391 		break;
1392 	case GREGADDRD:
1393 		ifreq_setaddr(cmd, ifr, sstosa(&sp->sp_dst));
1394 		break;
1395 	case GREDSOCK:
1396 		GRE_DPRINTF(sc, "\n");
1397 		if (sp->sp_bysock)
1398 			ifp->if_flags &= ~IFF_UP;
1399 		gre_clearconf(sp, false);
1400 		goto mksocket;
1401 	case GRESSOCK:
1402 		GRE_DPRINTF(sc, "\n");
1403 		gre_clearconf(sp, true);
1404 		fd = (int)ifr->ifr_value;
1405 		sp->sp_bysock = true;
1406 		ifp->if_flags |= IFF_UP;
1407 		goto setsock;
1408 	case SIOCSLIFPHYADDR:
1409 		GRE_DPRINTF(sc, "\n");
1410 		if (lifr->addr.ss_family != lifr->dstaddr.ss_family) {
1411 			error = EAFNOSUPPORT;
1412 			break;
1413 		}
1414 		sockaddr_copy(sstosa(&sp->sp_src), sizeof(sp->sp_src),
1415 		    sstosa(&lifr->addr));
1416 		sockaddr_copy(sstosa(&sp->sp_dst), sizeof(sp->sp_dst),
1417 		    sstosa(&lifr->dstaddr));
1418 		GRE_DPRINTF(sc, "\n");
1419 		goto checkaddr;
1420 	case SIOCDIFPHYADDR:
1421 		GRE_DPRINTF(sc, "\n");
1422 		gre_clearconf(sp, true);
1423 		ifp->if_flags &= ~IFF_UP;
1424 		goto mksocket;
1425 	case SIOCGLIFPHYADDR:
1426 		GRE_DPRINTF(sc, "\n");
1427 		if (gre_is_nullconf(sp)) {
1428 			error = EADDRNOTAVAIL;
1429 			break;
1430 		}
1431 		sockaddr_copy(sstosa(&lifr->addr), sizeof(lifr->addr),
1432 		    sstosa(&sp->sp_src));
1433 		sockaddr_copy(sstosa(&lifr->dstaddr), sizeof(lifr->dstaddr),
1434 		    sstosa(&sp->sp_dst));
1435 		GRE_DPRINTF(sc, "\n");
1436 		break;
1437 	default:
1438 		error = ifioctl_common(ifp, cmd, data);
1439 		break;
1440 	}
1441 out:
1442 	GRE_DPRINTF(sc, "\n");
1443 	splx(s);
1444 	return error;
1445 }
1446 
1447 /* ARGSUSED */
1448 void
1449 greattach(int count)
1450 {
1451 
1452 	/*
1453 	 * Nothing to do here, initialization is handled by the
1454 	 * module initialization code in greinit() below.
1455 	 */
1456 }
1457 
1458 static void
1459 greinit(void)
1460 {
1461 	if_clone_attach(&gre_cloner);
1462 }
1463 
1464 static int
1465 gredetach(void)
1466 {
1467 	int error = 0;
1468 
1469 	if (gre_count != 0)
1470 		error = EBUSY;
1471 
1472 	if (error == 0)
1473 		if_clone_detach(&gre_cloner);
1474 
1475 	return error;
1476 }
1477 
1478 /*
1479  * Module infrastructure
1480  */
1481 #include "if_module.h"
1482 
1483 IF_MODULE(MODULE_CLASS_DRIVER, gre, NULL)
1484