xref: /netbsd-src/sys/net/if_l2tp.c (revision 68d5c479122573b96283cfa711341e3fb22285d5)
1 /*	$NetBSD: if_l2tp.c,v 1.49 2023/11/02 09:43:46 yamaguchi Exp $	*/
2 
3 /*
4  * Copyright (c) 2017 Internet Initiative Japan Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /*
30  * L2TPv3 kernel interface
31  */
32 
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: if_l2tp.c,v 1.49 2023/11/02 09:43:46 yamaguchi Exp $");
35 
36 #ifdef _KERNEL_OPT
37 #include "opt_inet.h"
38 #include "opt_net_mpsafe.h"
39 #endif
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/mbuf.h>
45 #include <sys/socket.h>
46 #include <sys/sockio.h>
47 #include <sys/errno.h>
48 #include <sys/ioctl.h>
49 #include <sys/time.h>
50 #include <sys/syslog.h>
51 #include <sys/proc.h>
52 #include <sys/conf.h>
53 #include <sys/kauth.h>
54 #include <sys/cpu.h>
55 #include <sys/cprng.h>
56 #include <sys/intr.h>
57 #include <sys/kmem.h>
58 #include <sys/mutex.h>
59 #include <sys/atomic.h>
60 #include <sys/pserialize.h>
61 #include <sys/device.h>
62 #include <sys/module.h>
63 
64 #include <net/if.h>
65 #include <net/if_dl.h>
66 #include <net/if_ether.h>
67 #include <net/if_types.h>
68 #include <net/route.h>
69 #include <net/bpf.h>
70 #include <net/if_vlanvar.h>
71 
72 #include <netinet/in.h>
73 #include <netinet/in_systm.h>
74 #include <netinet/ip.h>
75 #include <netinet/ip_encap.h>
76 #ifdef	INET
77 #include <netinet/in_var.h>
78 #include <netinet/in_l2tp.h>
79 #endif	/* INET */
80 #ifdef INET6
81 #include <netinet6/in6_l2tp.h>
82 #endif
83 
84 #include <net/if_l2tp.h>
85 
86 #include <net/if_vlanvar.h>
87 
88 /* TODO: IP_TCPMSS support */
89 #undef IP_TCPMSS
90 #ifdef IP_TCPMSS
91 #include <netinet/ip_tcpmss.h>
92 #endif
93 
94 /*
95  * l2tp global variable definitions
96  */
97 static struct {
98 	LIST_HEAD(l2tp_sclist, l2tp_softc) list;
99 	kmutex_t lock;
100 } l2tp_softcs __cacheline_aligned;
101 
102 
103 #if !defined(L2TP_ID_HASH_SIZE)
104 #define L2TP_ID_HASH_SIZE 64
105 #endif
106 static struct {
107 	kmutex_t lock;
108 	struct pslist_head *lists;
109 	u_long mask;
110 } l2tp_hash __cacheline_aligned = {
111 	.lists = NULL,
112 };
113 
114 pserialize_t l2tp_psz __read_mostly;
115 struct psref_class *lv_psref_class __read_mostly;
116 
117 static void	l2tp_ifq_init_pc(void *, void *, struct cpu_info *);
118 static void	l2tp_ifq_fini_pc(void *, void *, struct cpu_info *);
119 
120 static int	l2tp_clone_create(struct if_clone *, int);
121 static int	l2tp_clone_destroy(struct ifnet *);
122 
123 struct if_clone l2tp_cloner =
124     IF_CLONE_INITIALIZER("l2tp", l2tp_clone_create, l2tp_clone_destroy);
125 
126 static int	l2tp_tx_enqueue(struct l2tp_variant *, struct mbuf *);
127 static int	l2tp_output(struct ifnet *, struct mbuf *,
128 		    const struct sockaddr *, const struct rtentry *);
129 static void	l2tp_sendit(struct l2tp_variant *, struct mbuf *);
130 static void	l2tpintr(struct l2tp_variant *);
131 static void	l2tpintr_softint(void *);
132 
133 static void	l2tp_hash_init(void);
134 static int	l2tp_hash_fini(void);
135 
136 static void	l2tp_start(struct ifnet *);
137 static int	l2tp_transmit(struct ifnet *, struct mbuf *);
138 
139 static int	l2tp_set_tunnel(struct ifnet *, struct sockaddr *,
140 		    struct sockaddr *);
141 static void	l2tp_delete_tunnel(struct ifnet *);
142 
143 static int	id_hash_func(uint32_t, u_long);
144 
145 static void	l2tp_variant_update(struct l2tp_softc *, struct l2tp_variant *);
146 static int	l2tp_set_session(struct l2tp_softc *, uint32_t, uint32_t);
147 static int	l2tp_clear_session(struct l2tp_softc *);
148 static int	l2tp_set_cookie(struct l2tp_softc *, uint64_t, u_int, uint64_t, u_int);
149 static void	l2tp_clear_cookie(struct l2tp_softc *);
150 static void	l2tp_set_state(struct l2tp_softc *, int);
151 static int	l2tp_encap_attach(struct l2tp_variant *);
152 static int	l2tp_encap_detach(struct l2tp_variant *);
153 
154 static inline struct ifqueue *
l2tp_ifq_percpu_getref(percpu_t * pc)155 l2tp_ifq_percpu_getref(percpu_t *pc)
156 {
157 
158 	return *(struct ifqueue **)percpu_getref(pc);
159 }
160 
161 static inline void
l2tp_ifq_percpu_putref(percpu_t * pc)162 l2tp_ifq_percpu_putref(percpu_t *pc)
163 {
164 
165 	percpu_putref(pc);
166 }
167 
168 #ifndef MAX_L2TP_NEST
169 /*
170  * This macro controls the upper limitation on nesting of l2tp tunnels.
171  * Since, setting a large value to this macro with a careless configuration
172  * may introduce system crash, we don't allow any nestings by default.
173  * If you need to configure nested l2tp tunnels, you can define this macro
174  * in your kernel configuration file.  However, if you do so, please be
175  * careful to configure the tunnels so that it won't make a loop.
176  */
177 /*
178  * XXX
179  * Currently, if in_l2tp_output recursively calls, it causes locking against
180  * myself of struct l2tp_ro->lr_lock. So, nested l2tp tunnels is prohibited.
181  */
182 #define MAX_L2TP_NEST 0
183 #endif
184 
185 static int max_l2tp_nesting = MAX_L2TP_NEST;
186 
187 /* ARGSUSED */
188 void
l2tpattach(int count)189 l2tpattach(int count)
190 {
191 	/*
192 	 * Nothing to do here, initialization is handled by the
193 	 * module initialization code in l2tpinit() below).
194 	 */
195 }
196 
197 static void
l2tpinit(void)198 l2tpinit(void)
199 {
200 
201 	mutex_init(&l2tp_softcs.lock, MUTEX_DEFAULT, IPL_NONE);
202 	LIST_INIT(&l2tp_softcs.list);
203 
204 	mutex_init(&l2tp_hash.lock, MUTEX_DEFAULT, IPL_NONE);
205 	l2tp_psz = pserialize_create();
206 	lv_psref_class = psref_class_create("l2tpvar", IPL_SOFTNET);
207 	if_clone_attach(&l2tp_cloner);
208 
209 	l2tp_hash_init();
210 }
211 
212 static int
l2tpdetach(void)213 l2tpdetach(void)
214 {
215 	int error;
216 
217 	mutex_enter(&l2tp_softcs.lock);
218 	if (!LIST_EMPTY(&l2tp_softcs.list)) {
219 		mutex_exit(&l2tp_softcs.lock);
220 		return EBUSY;
221 	}
222 	mutex_exit(&l2tp_softcs.lock);
223 
224 	error = l2tp_hash_fini();
225 	if (error)
226 		return error;
227 
228 	if_clone_detach(&l2tp_cloner);
229 	psref_class_destroy(lv_psref_class);
230 	pserialize_destroy(l2tp_psz);
231 	mutex_destroy(&l2tp_hash.lock);
232 
233 	mutex_destroy(&l2tp_softcs.lock);
234 
235 	return error;
236 }
237 
238 static int
l2tp_clone_create(struct if_clone * ifc,int unit)239 l2tp_clone_create(struct if_clone *ifc, int unit)
240 {
241 	struct l2tp_softc *sc;
242 	struct l2tp_variant *var;
243 	int rv;
244 	u_int si_flags = SOFTINT_NET;
245 #ifdef NET_MPSAFE
246 	si_flags |= SOFTINT_MPSAFE;
247 #endif
248 	sc = kmem_zalloc(sizeof(struct l2tp_softc), KM_SLEEP);
249 	if_initname(&sc->l2tp_ec.ec_if, ifc->ifc_name, unit);
250 	rv = l2tpattach0(sc);
251 	if (rv != 0) {
252 		kmem_free(sc, sizeof(struct l2tp_softc));
253 		return rv;
254 	}
255 
256 	var = kmem_zalloc(sizeof(struct l2tp_variant), KM_SLEEP);
257 	var->lv_softc = sc;
258 	var->lv_state = L2TP_STATE_DOWN;
259 	var->lv_use_cookie = L2TP_COOKIE_OFF;
260 	psref_target_init(&var->lv_psref, lv_psref_class);
261 
262 	sc->l2tp_var = var;
263 	mutex_init(&sc->l2tp_lock, MUTEX_DEFAULT, IPL_NONE);
264 	sc->l2tp_psz = pserialize_create();
265 	PSLIST_ENTRY_INIT(sc, l2tp_hash);
266 
267 	sc->l2tp_ro_percpu = if_tunnel_alloc_ro_percpu();
268 
269 	sc->l2tp_ifq_percpu = percpu_create(sizeof(struct ifqueue *),
270 	    l2tp_ifq_init_pc, l2tp_ifq_fini_pc, NULL);
271 	sc->l2tp_si = softint_establish(si_flags, l2tpintr_softint, sc);
272 
273 	mutex_enter(&l2tp_softcs.lock);
274 	LIST_INSERT_HEAD(&l2tp_softcs.list, sc, l2tp_list);
275 	mutex_exit(&l2tp_softcs.lock);
276 
277 	return (0);
278 }
279 
280 int
l2tpattach0(struct l2tp_softc * sc)281 l2tpattach0(struct l2tp_softc *sc)
282 {
283 
284 	sc->l2tp_ec.ec_capabilities = 0;
285 	sc->l2tp_ec.ec_capabilities |= ETHERCAP_VLAN_MTU;
286 	sc->l2tp_ec.ec_capabilities |= ETHERCAP_JUMBO_MTU;
287 
288 	ether_ifattach(&sc->l2tp_ec.ec_if, NULL);
289 
290 	sc->l2tp_ec.ec_if.if_addrlen = 0;
291 	sc->l2tp_ec.ec_if.if_mtu    = L2TP_MTU;
292 	sc->l2tp_ec.ec_if.if_flags  = IFF_POINTOPOINT|IFF_MULTICAST|IFF_SIMPLEX;
293 #ifdef NET_MPSAFE
294 	sc->l2tp_ec.ec_if.if_extflags = IFEF_MPSAFE;
295 #endif
296 	sc->l2tp_ec.ec_if.if_ioctl  = l2tp_ioctl;
297 	sc->l2tp_ec.ec_if.if_output = l2tp_output;
298 	sc->l2tp_ec.ec_if.if_type   = IFT_L2TP;
299 	sc->l2tp_ec.ec_if.if_dlt    = DLT_NULL;
300 	sc->l2tp_ec.ec_if.if_start  = l2tp_start;
301 	sc->l2tp_ec.ec_if.if_transmit = l2tp_transmit;
302 	sc->l2tp_ec.ec_if._if_input = ether_input;
303 	IFQ_SET_READY(&sc->l2tp_ec.ec_if.if_snd);
304 
305 	/* XXX
306 	 * It may improve performance to use if_initialize()/if_register()
307 	 * so that l2tp_input() calls if_input() instead of
308 	 * if_percpuq_enqueue(). However, that causes recursive softnet_lock
309 	 * when NET_MPSAFE is not set.
310 	 */
311 	if_attach(&sc->l2tp_ec.ec_if);
312 	if_link_state_change(&sc->l2tp_ec.ec_if, LINK_STATE_DOWN);
313 	if_alloc_sadl(&sc->l2tp_ec.ec_if);
314 
315 	return 0;
316 }
317 
318 void
l2tp_ifq_init_pc(void * p,void * arg __unused,struct cpu_info * ci __unused)319 l2tp_ifq_init_pc(void *p, void *arg __unused, struct cpu_info *ci __unused)
320 {
321 	struct ifqueue **ifqp = p;
322 
323 	*ifqp = kmem_zalloc(sizeof(**ifqp), KM_SLEEP);
324 	(*ifqp)->ifq_maxlen = IFQ_MAXLEN;
325 }
326 
327 void
l2tp_ifq_fini_pc(void * p,void * arg __unused,struct cpu_info * ci __unused)328 l2tp_ifq_fini_pc(void *p, void *arg __unused, struct cpu_info *ci __unused)
329 {
330 	struct ifqueue **ifqp = p;
331 
332 	kmem_free(*ifqp, sizeof(**ifqp));
333 }
334 
335 static int
l2tp_clone_destroy(struct ifnet * ifp)336 l2tp_clone_destroy(struct ifnet *ifp)
337 {
338 	struct l2tp_variant *var;
339 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
340 	    l2tp_ec.ec_if);
341 
342 	ether_ifdetach(ifp);
343 
344 	l2tp_clear_session(sc);
345 	l2tp_delete_tunnel(&sc->l2tp_ec.ec_if);
346 	/*
347 	 * To avoid for l2tp_transmit() and l2tpintr_softint() to access
348 	 * sc->l2tp_var after free it.
349 	 */
350 	mutex_enter(&sc->l2tp_lock);
351 	var = sc->l2tp_var;
352 	l2tp_variant_update(sc, NULL);
353 	mutex_exit(&sc->l2tp_lock);
354 
355 	softint_disestablish(sc->l2tp_si);
356 	percpu_free(sc->l2tp_ifq_percpu, sizeof(struct ifqueue *));
357 
358 	mutex_enter(&l2tp_softcs.lock);
359 	LIST_REMOVE(sc, l2tp_list);
360 	mutex_exit(&l2tp_softcs.lock);
361 
362 	if_detach(ifp);
363 
364 	if_tunnel_free_ro_percpu(sc->l2tp_ro_percpu);
365 
366 	kmem_free(var, sizeof(struct l2tp_variant));
367 	pserialize_destroy(sc->l2tp_psz);
368 	mutex_destroy(&sc->l2tp_lock);
369 	kmem_free(sc, sizeof(struct l2tp_softc));
370 
371 	return 0;
372 }
373 
374 static int
l2tp_tx_enqueue(struct l2tp_variant * var,struct mbuf * m)375 l2tp_tx_enqueue(struct l2tp_variant *var, struct mbuf *m)
376 {
377 	struct l2tp_softc *sc;
378 	struct ifnet *ifp;
379 	struct ifqueue *ifq;
380 	int s;
381 
382 	KASSERT(psref_held(&var->lv_psref, lv_psref_class));
383 
384 	sc = var->lv_softc;
385 	ifp = &sc->l2tp_ec.ec_if;
386 
387 	s = splsoftnet();
388 	ifq = l2tp_ifq_percpu_getref(sc->l2tp_ifq_percpu);
389 	if (IF_QFULL(ifq)) {
390 		if_statinc(ifp, if_oerrors);
391 		l2tp_ifq_percpu_putref(sc->l2tp_ifq_percpu);
392 		splx(s);
393 		m_freem(m);
394 		return ENOBUFS;
395 	}
396 
397 	IF_ENQUEUE(ifq, m);
398 	percpu_putref(sc->l2tp_ifq_percpu);
399 	softint_schedule(sc->l2tp_si);
400 	/* counter is incremented in l2tpintr() */
401 	splx(s);
402 	return 0;
403 }
404 
405 static int
l2tp_output(struct ifnet * ifp,struct mbuf * m,const struct sockaddr * dst,const struct rtentry * rt)406 l2tp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
407     const struct rtentry *rt)
408 {
409 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
410 	    l2tp_ec.ec_if);
411 	struct l2tp_variant *var;
412 	struct psref psref;
413 	int error = 0;
414 
415 	var = l2tp_getref_variant(sc, &psref);
416 	if (var == NULL) {
417 		m_freem(m);
418 		return ENETDOWN;
419 	}
420 
421 	IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
422 
423 	m->m_flags &= ~(M_BCAST|M_MCAST);
424 
425 	if ((ifp->if_flags & IFF_UP) == 0) {
426 		m_freem(m);
427 		error = ENETDOWN;
428 		goto end;
429 	}
430 
431 	if (var->lv_psrc == NULL || var->lv_pdst == NULL) {
432 		m_freem(m);
433 		error = ENETDOWN;
434 		goto end;
435 	}
436 
437 	/* XXX should we check if our outer source is legal? */
438 
439 	/* use DLT_NULL encapsulation here to pass inner af type */
440 	M_PREPEND(m, sizeof(int), M_DONTWAIT);
441 	if (!m) {
442 		error = ENOBUFS;
443 		goto end;
444 	}
445 	*mtod(m, int *) = dst->sa_family;
446 
447 	error = l2tp_tx_enqueue(var, m);
448 end:
449 	l2tp_putref_variant(var, &psref);
450 	if (error)
451 		if_statinc(ifp, if_oerrors);
452 
453 	return error;
454 }
455 
456 static void
l2tp_sendit(struct l2tp_variant * var,struct mbuf * m)457 l2tp_sendit(struct l2tp_variant *var, struct mbuf *m)
458 {
459 	int len;
460 	int error;
461 	struct l2tp_softc *sc;
462 	struct ifnet *ifp;
463 
464 	KASSERT(psref_held(&var->lv_psref, lv_psref_class));
465 
466 	sc = var->lv_softc;
467 	ifp = &sc->l2tp_ec.ec_if;
468 
469 	len = m->m_pkthdr.len;
470 	m->m_flags &= ~(M_BCAST|M_MCAST);
471 	bpf_mtap(ifp, m, BPF_D_OUT);
472 
473 	switch (var->lv_psrc->sa_family) {
474 #ifdef INET
475 	case AF_INET:
476 		error = in_l2tp_output(var, m);
477 		break;
478 #endif
479 #ifdef INET6
480 	case AF_INET6:
481 		error = in6_l2tp_output(var, m);
482 		break;
483 #endif
484 	default:
485 		m_freem(m);
486 		error = ENETDOWN;
487 		break;
488 	}
489 	if (error) {
490 		if_statinc(ifp, if_oerrors);
491 	} else {
492 		if_statadd2(ifp, if_opackets, 1, if_obytes, len);
493 	}
494 }
495 
496 static void
l2tpintr(struct l2tp_variant * var)497 l2tpintr(struct l2tp_variant *var)
498 {
499 	struct l2tp_softc *sc;
500 	struct ifnet *ifp;
501 	struct mbuf *m;
502 	struct ifqueue *ifq;
503 	u_int cpuid = cpu_index(curcpu());
504 
505 	KASSERT(psref_held(&var->lv_psref, lv_psref_class));
506 
507 	sc = var->lv_softc;
508 	ifp = &sc->l2tp_ec.ec_if;
509 
510 	/* output processing */
511 	if (var->lv_my_sess_id == 0 || var->lv_peer_sess_id == 0) {
512 		ifq = l2tp_ifq_percpu_getref(sc->l2tp_ifq_percpu);
513 		IF_PURGE(ifq);
514 		l2tp_ifq_percpu_putref(sc->l2tp_ifq_percpu);
515 		if (cpuid == 0)
516 			IFQ_PURGE(&ifp->if_snd);
517 		return;
518 	}
519 
520 	/* Currently, l2tpintr() is always called in softint context. */
521 	ifq = l2tp_ifq_percpu_getref(sc->l2tp_ifq_percpu);
522 	for (;;) {
523 		IF_DEQUEUE(ifq, m);
524 		if (m != NULL)
525 			l2tp_sendit(var, m);
526 		else
527 			break;
528 	}
529 	l2tp_ifq_percpu_putref(sc->l2tp_ifq_percpu);
530 
531 	if (cpuid == 0) {
532 		for (;;) {
533 			IFQ_DEQUEUE(&ifp->if_snd, m);
534 			if (m != NULL)
535 				l2tp_sendit(var, m);
536 			else
537 				break;
538 		}
539 	}
540 }
541 
542 static void
l2tpintr_softint(void * arg)543 l2tpintr_softint(void *arg)
544 {
545 	struct l2tp_variant *var;
546 	struct psref psref;
547 	struct l2tp_softc *sc = arg;
548 
549 	var = l2tp_getref_variant(sc, &psref);
550 	if (var == NULL)
551 		return;
552 
553 	l2tpintr(var);
554 	l2tp_putref_variant(var, &psref);
555 }
556 
557 void
l2tp_input(struct mbuf * m,struct ifnet * ifp)558 l2tp_input(struct mbuf *m, struct ifnet *ifp)
559 {
560 	vaddr_t addr;
561 
562 	KASSERT(ifp != NULL);
563 
564 	/*
565 	 * Currently, l2tp(4) supports only ethernet as inner protocol.
566 	 */
567 	if (m->m_pkthdr.len < sizeof(struct ether_header)) {
568 		m_freem(m);
569 		return;
570 	}
571 
572 	/*
573 	 * If the head of the payload is not aligned, align it.
574 	 */
575 	addr = mtod(m, vaddr_t);
576 	if ((addr & 0x03) != 0x2) {
577 		/* copy and align head of payload */
578 		struct mbuf *m_head;
579 		int copy_length;
580 		u_int pad = roundup(sizeof(struct ether_header), 4)
581 			- sizeof(struct ether_header);
582 
583 #define L2TP_COPY_LENGTH		60
584 
585 		if (m->m_pkthdr.len < L2TP_COPY_LENGTH) {
586 			copy_length = m->m_pkthdr.len;
587 		} else {
588 			copy_length = L2TP_COPY_LENGTH;
589 		}
590 
591 		if (m->m_len < copy_length) {
592 			m = m_pullup(m, copy_length);
593 			if (m == NULL)
594 				return;
595 		}
596 
597 		MGETHDR(m_head, M_DONTWAIT, MT_HEADER);
598 		if (m_head == NULL) {
599 			m_freem(m);
600 			return;
601 		}
602 		m_move_pkthdr(m_head, m);
603 
604 		/*
605 		 * m_head should be:
606 		 *                             L2TP_COPY_LENGTH
607 		 *                          <-  + roundup(pad, 4) - pad ->
608 		 *   +-------+--------+-----+--------------+-------------+
609 		 *   | m_hdr | pkthdr | ... | ether header |   payload   |
610 		 *   +-------+--------+-----+--------------+-------------+
611 		 *                          ^              ^
612 		 *                          m_data         4 byte aligned
613 		 */
614 		m_align(m_head, L2TP_COPY_LENGTH + roundup(pad, 4));
615 		m_head->m_data += pad;
616 
617 		memcpy(mtod(m_head, void *), mtod(m, void *), copy_length);
618 		m_head->m_len = copy_length;
619 		m->m_data += copy_length;
620 		m->m_len -= copy_length;
621 
622 		/* construct chain */
623 		if (m->m_len == 0) {
624 			m_head->m_next = m_free(m);
625 		} else {
626 			m_head->m_next = m;
627 		}
628 
629 		/* override m */
630 		m = m_head;
631 	}
632 
633 	m_set_rcvif(m, ifp);
634 
635 	/*
636 	 * bpf_mtap() and ifp->if_ipackets++ is done in if_input()
637 	 *
638 	 * obytes is incremented at ether_output() or bridge_enqueue().
639 	 */
640 	if_percpuq_enqueue(ifp->if_percpuq, m);
641 }
642 
643 void
l2tp_start(struct ifnet * ifp)644 l2tp_start(struct ifnet *ifp)
645 {
646 	struct psref psref;
647 	struct l2tp_variant *var;
648 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
649 	    l2tp_ec.ec_if);
650 
651 	var = l2tp_getref_variant(sc, &psref);
652 	if (var == NULL)
653 		return;
654 
655 	if (var->lv_psrc == NULL || var->lv_pdst == NULL)
656 		return;
657 
658 	kpreempt_disable();
659 	softint_schedule(sc->l2tp_si);
660 	kpreempt_enable();
661 	l2tp_putref_variant(var, &psref);
662 }
663 
664 int
l2tp_transmit(struct ifnet * ifp,struct mbuf * m)665 l2tp_transmit(struct ifnet *ifp, struct mbuf *m)
666 {
667 	int error;
668 	struct psref psref;
669 	struct l2tp_variant *var;
670 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
671 	    l2tp_ec.ec_if);
672 
673 	var = l2tp_getref_variant(sc, &psref);
674 	if (var == NULL) {
675 		m_freem(m);
676 		return ENETDOWN;
677 	}
678 
679 	if (var->lv_psrc == NULL || var->lv_pdst == NULL) {
680 		m_freem(m);
681 		error = ENETDOWN;
682 		goto out;
683 	}
684 
685 	m->m_flags &= ~(M_BCAST|M_MCAST);
686 
687 	error = l2tp_tx_enqueue(var, m);
688 out:
689 	l2tp_putref_variant(var, &psref);
690 	return error;
691 }
692 
693 /* XXX how should we handle IPv6 scope on SIOC[GS]IFPHYADDR? */
694 int
l2tp_ioctl(struct ifnet * ifp,u_long cmd,void * data)695 l2tp_ioctl(struct ifnet *ifp, u_long cmd, void *data)
696 {
697 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
698 	    l2tp_ec.ec_if);
699 	struct l2tp_variant *var, *var_tmp;
700 	struct ifreq     *ifr = data;
701 	int error = 0, size;
702 	struct sockaddr *dst, *src;
703 	struct l2tp_req l2tpr;
704 	u_long mtu;
705 	int bound;
706 	struct psref psref;
707 
708 	switch (cmd) {
709 	case SIOCSIFADDR:
710 		ifp->if_flags |= IFF_UP;
711 		break;
712 
713 	case SIOCSIFDSTADDR:
714 		break;
715 
716 	case SIOCADDMULTI:
717 	case SIOCDELMULTI:
718 		switch (ifr->ifr_addr.sa_family) {
719 #ifdef INET
720 		case AF_INET:	/* IP supports Multicast */
721 			break;
722 #endif /* INET */
723 #ifdef INET6
724 		case AF_INET6:	/* IP6 supports Multicast */
725 			break;
726 #endif /* INET6 */
727 		default:  /* Other protocols doesn't support Multicast */
728 			error = EAFNOSUPPORT;
729 			break;
730 		}
731 		break;
732 
733 	case SIOCSIFMTU:
734 		mtu = ifr->ifr_mtu;
735 		if (mtu < L2TP_MTU_MIN || mtu > L2TP_MTU_MAX)
736 			return (EINVAL);
737 		ifp->if_mtu = mtu;
738 		break;
739 
740 #ifdef INET
741 	case SIOCSIFPHYADDR:
742 		src = (struct sockaddr *)
743 			&(((struct in_aliasreq *)data)->ifra_addr);
744 		dst = (struct sockaddr *)
745 			&(((struct in_aliasreq *)data)->ifra_dstaddr);
746 		if (src->sa_family != AF_INET || dst->sa_family != AF_INET)
747 			return EAFNOSUPPORT;
748 		else if (src->sa_len != sizeof(struct sockaddr_in)
749 		    || dst->sa_len != sizeof(struct sockaddr_in))
750 			return EINVAL;
751 
752 		error = l2tp_set_tunnel(&sc->l2tp_ec.ec_if, src, dst);
753 		break;
754 
755 #endif /* INET */
756 #ifdef INET6
757 	case SIOCSIFPHYADDR_IN6:
758 		src = (struct sockaddr *)
759 			&(((struct in6_aliasreq *)data)->ifra_addr);
760 		dst = (struct sockaddr *)
761 			&(((struct in6_aliasreq *)data)->ifra_dstaddr);
762 		if (src->sa_family != AF_INET6 || dst->sa_family != AF_INET6)
763 			return EAFNOSUPPORT;
764 		else if (src->sa_len != sizeof(struct sockaddr_in6)
765 		    || dst->sa_len != sizeof(struct sockaddr_in6))
766 			return EINVAL;
767 
768 		error = l2tp_set_tunnel(&sc->l2tp_ec.ec_if, src, dst);
769 		break;
770 
771 #endif /* INET6 */
772 	case SIOCSLIFPHYADDR:
773 		src = (struct sockaddr *)
774 			&(((struct if_laddrreq *)data)->addr);
775 		dst = (struct sockaddr *)
776 			&(((struct if_laddrreq *)data)->dstaddr);
777 		if (src->sa_family != dst->sa_family)
778 			return EINVAL;
779 		else if (src->sa_family == AF_INET
780 		    && src->sa_len != sizeof(struct sockaddr_in))
781 			return EINVAL;
782 		else if (src->sa_family == AF_INET6
783 		    && src->sa_len != sizeof(struct sockaddr_in6))
784 			return EINVAL;
785 		else if (dst->sa_family == AF_INET
786 		    && dst->sa_len != sizeof(struct sockaddr_in))
787 			return EINVAL;
788 		else if (dst->sa_family == AF_INET6
789 		    && dst->sa_len != sizeof(struct sockaddr_in6))
790 			return EINVAL;
791 
792 		error = l2tp_set_tunnel(&sc->l2tp_ec.ec_if, src, dst);
793 		break;
794 
795 	case SIOCDIFPHYADDR:
796 		l2tp_delete_tunnel(&sc->l2tp_ec.ec_if);
797 		break;
798 
799 	case SIOCGIFPSRCADDR:
800 #ifdef INET6
801 	case SIOCGIFPSRCADDR_IN6:
802 #endif /* INET6 */
803 		bound = curlwp_bind();
804 		var = l2tp_getref_variant(sc, &psref);
805 		if (var == NULL) {
806 			curlwp_bindx(bound);
807 			error = EADDRNOTAVAIL;
808 			goto bad;
809 		}
810 		if (var->lv_psrc == NULL) {
811 			l2tp_putref_variant(var, &psref);
812 			curlwp_bindx(bound);
813 			error = EADDRNOTAVAIL;
814 			goto bad;
815 		}
816 		src = var->lv_psrc;
817 		switch (cmd) {
818 #ifdef INET
819 		case SIOCGIFPSRCADDR:
820 			dst = &ifr->ifr_addr;
821 			size = sizeof(ifr->ifr_addr);
822 			break;
823 #endif /* INET */
824 #ifdef INET6
825 		case SIOCGIFPSRCADDR_IN6:
826 			dst = (struct sockaddr *)
827 				&(((struct in6_ifreq *)data)->ifr_addr);
828 			size = sizeof(((struct in6_ifreq *)data)->ifr_addr);
829 			break;
830 #endif /* INET6 */
831 		default:
832 			l2tp_putref_variant(var, &psref);
833 			curlwp_bindx(bound);
834 			error = EADDRNOTAVAIL;
835 			goto bad;
836 		}
837 		if (src->sa_len > size) {
838 			l2tp_putref_variant(var, &psref);
839 			curlwp_bindx(bound);
840 			return EINVAL;
841 		}
842 		sockaddr_copy(dst, src->sa_len, src);
843 		l2tp_putref_variant(var, &psref);
844 		curlwp_bindx(bound);
845 		break;
846 
847 	case SIOCGIFPDSTADDR:
848 #ifdef INET6
849 	case SIOCGIFPDSTADDR_IN6:
850 #endif /* INET6 */
851 		bound = curlwp_bind();
852 		var = l2tp_getref_variant(sc, &psref);
853 		if (var == NULL) {
854 			curlwp_bindx(bound);
855 			error = EADDRNOTAVAIL;
856 			goto bad;
857 		}
858 		if (var->lv_pdst == NULL) {
859 			l2tp_putref_variant(var, &psref);
860 			curlwp_bindx(bound);
861 			error = EADDRNOTAVAIL;
862 			goto bad;
863 		}
864 		src = var->lv_pdst;
865 		switch (cmd) {
866 #ifdef INET
867 		case SIOCGIFPDSTADDR:
868 			dst = &ifr->ifr_addr;
869 			size = sizeof(ifr->ifr_addr);
870 			break;
871 #endif /* INET */
872 #ifdef INET6
873 		case SIOCGIFPDSTADDR_IN6:
874 			dst = (struct sockaddr *)
875 				&(((struct in6_ifreq *)data)->ifr_addr);
876 			size = sizeof(((struct in6_ifreq *)data)->ifr_addr);
877 			break;
878 #endif /* INET6 */
879 		default:
880 			l2tp_putref_variant(var, &psref);
881 			curlwp_bindx(bound);
882 			error = EADDRNOTAVAIL;
883 			goto bad;
884 		}
885 		if (src->sa_len > size) {
886 			l2tp_putref_variant(var, &psref);
887 			curlwp_bindx(bound);
888 			return EINVAL;
889 		}
890 		sockaddr_copy(dst, src->sa_len, src);
891 		l2tp_putref_variant(var, &psref);
892 		curlwp_bindx(bound);
893 		break;
894 
895 	case SIOCGLIFPHYADDR:
896 		bound = curlwp_bind();
897 		var = l2tp_getref_variant(sc, &psref);
898 		if (var == NULL) {
899 			curlwp_bindx(bound);
900 			error = EADDRNOTAVAIL;
901 			goto bad;
902 		}
903 		if (var->lv_psrc == NULL || var->lv_pdst == NULL) {
904 			l2tp_putref_variant(var, &psref);
905 			curlwp_bindx(bound);
906 			error = EADDRNOTAVAIL;
907 			goto bad;
908 		}
909 
910 		/* copy src */
911 		src = var->lv_psrc;
912 		dst = (struct sockaddr *)
913 			&(((struct if_laddrreq *)data)->addr);
914 		size = sizeof(((struct if_laddrreq *)data)->addr);
915 		if (src->sa_len > size) {
916 			l2tp_putref_variant(var, &psref);
917 			curlwp_bindx(bound);
918 			return EINVAL;
919                 }
920 		sockaddr_copy(dst, src->sa_len, src);
921 
922 		/* copy dst */
923 		src = var->lv_pdst;
924 		dst = (struct sockaddr *)
925 			&(((struct if_laddrreq *)data)->dstaddr);
926 		size = sizeof(((struct if_laddrreq *)data)->dstaddr);
927 		if (src->sa_len > size) {
928 			l2tp_putref_variant(var, &psref);
929 			curlwp_bindx(bound);
930 			return EINVAL;
931                 }
932 		sockaddr_copy(dst, src->sa_len, src);
933 		l2tp_putref_variant(var, &psref);
934 		curlwp_bindx(bound);
935 		break;
936 
937 	case SIOCSL2TPSESSION:
938 		if ((error = copyin(ifr->ifr_data, &l2tpr, sizeof(l2tpr))) != 0)
939 			break;
940 
941 		/* session id must not zero */
942 		if (l2tpr.my_sess_id == 0 || l2tpr.peer_sess_id == 0)
943 			return EINVAL;
944 
945 		bound = curlwp_bind();
946 		var_tmp = l2tp_lookup_session_ref(l2tpr.my_sess_id, &psref);
947 		if (var_tmp != NULL) {
948 			/* duplicate session id */
949 			log(LOG_WARNING, "%s: duplicate session id %" PRIu32 " of %s\n",
950 				sc->l2tp_ec.ec_if.if_xname, l2tpr.my_sess_id,
951 				var_tmp->lv_softc->l2tp_ec.ec_if.if_xname);
952 			psref_release(&psref, &var_tmp->lv_psref,
953 			    lv_psref_class);
954 			curlwp_bindx(bound);
955 			return EINVAL;
956 		}
957 		curlwp_bindx(bound);
958 
959 		error = l2tp_set_session(sc, l2tpr.my_sess_id, l2tpr.peer_sess_id);
960 		break;
961 	case SIOCDL2TPSESSION:
962 		l2tp_clear_session(sc);
963 		break;
964 	case SIOCSL2TPCOOKIE:
965 		if ((error = copyin(ifr->ifr_data, &l2tpr, sizeof(l2tpr))) != 0)
966 			break;
967 
968 		error = l2tp_set_cookie(sc, l2tpr.my_cookie, l2tpr.my_cookie_len,
969 		    l2tpr.peer_cookie, l2tpr.peer_cookie_len);
970 		break;
971 	case SIOCDL2TPCOOKIE:
972 		l2tp_clear_cookie(sc);
973 		break;
974 	case SIOCSL2TPSTATE:
975 		if ((error = copyin(ifr->ifr_data, &l2tpr, sizeof(l2tpr))) != 0)
976 			break;
977 
978 		l2tp_set_state(sc, l2tpr.state);
979 		break;
980 	case SIOCGL2TP:
981 		/* get L2TPV3 session info */
982 		memset(&l2tpr, 0, sizeof(l2tpr));
983 
984 		bound = curlwp_bind();
985 		var = l2tp_getref_variant(sc, &psref);
986 		if (var == NULL) {
987 			curlwp_bindx(bound);
988 			error = EADDRNOTAVAIL;
989 			goto bad;
990 		}
991 
992 		l2tpr.state = var->lv_state;
993 		l2tpr.my_sess_id = var->lv_my_sess_id;
994 		l2tpr.peer_sess_id = var->lv_peer_sess_id;
995 		l2tpr.my_cookie = var->lv_my_cookie;
996 		l2tpr.my_cookie_len = var->lv_my_cookie_len;
997 		l2tpr.peer_cookie = var->lv_peer_cookie;
998 		l2tpr.peer_cookie_len = var->lv_peer_cookie_len;
999 		l2tp_putref_variant(var, &psref);
1000 		curlwp_bindx(bound);
1001 
1002 		error = copyout(&l2tpr, ifr->ifr_data, sizeof(l2tpr));
1003 		break;
1004 
1005 	default:
1006 		error =	ifioctl_common(ifp, cmd, data);
1007 		break;
1008 	}
1009  bad:
1010 	return error;
1011 }
1012 
1013 static int
l2tp_set_tunnel(struct ifnet * ifp,struct sockaddr * src,struct sockaddr * dst)1014 l2tp_set_tunnel(struct ifnet *ifp, struct sockaddr *src, struct sockaddr *dst)
1015 {
1016 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
1017 	    l2tp_ec.ec_if);
1018 	struct sockaddr *osrc, *odst;
1019 	struct sockaddr *nsrc, *ndst;
1020 	struct l2tp_variant *ovar, *nvar;
1021 	int error;
1022 
1023 	nsrc = sockaddr_dup(src, M_WAITOK);
1024 	ndst = sockaddr_dup(dst, M_WAITOK);
1025 
1026 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1027 
1028 	error = encap_lock_enter();
1029 	if (error)
1030 		goto error;
1031 
1032 	mutex_enter(&sc->l2tp_lock);
1033 
1034 	ovar = sc->l2tp_var;
1035 	osrc = ovar->lv_psrc;
1036 	odst = ovar->lv_pdst;
1037 	*nvar = *ovar;
1038 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1039 	nvar->lv_psrc = nsrc;
1040 	nvar->lv_pdst = ndst;
1041 	error = l2tp_encap_attach(nvar);
1042 	if (error) {
1043 		mutex_exit(&sc->l2tp_lock);
1044 		encap_lock_exit();
1045 		goto error;
1046 	}
1047 	l2tp_variant_update(sc, nvar);
1048 
1049 	mutex_exit(&sc->l2tp_lock);
1050 
1051 	(void)l2tp_encap_detach(ovar);
1052 	encap_lock_exit();
1053 
1054 	if (osrc)
1055 		sockaddr_free(osrc);
1056 	if (odst)
1057 		sockaddr_free(odst);
1058 	kmem_free(ovar, sizeof(*ovar));
1059 	return 0;
1060 
1061 error:
1062 	sockaddr_free(nsrc);
1063 	sockaddr_free(ndst);
1064 	kmem_free(nvar, sizeof(*nvar));
1065 
1066 	return error;
1067 }
1068 
1069 static void
l2tp_delete_tunnel(struct ifnet * ifp)1070 l2tp_delete_tunnel(struct ifnet *ifp)
1071 {
1072 	struct l2tp_softc *sc = container_of(ifp, struct l2tp_softc,
1073 	    l2tp_ec.ec_if);
1074 	struct sockaddr *osrc, *odst;
1075 	struct l2tp_variant *ovar, *nvar;
1076 	int error;
1077 
1078 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1079 
1080 	error = encap_lock_enter();
1081 	if (error) {
1082 		kmem_free(nvar, sizeof(*nvar));
1083 		return;
1084 	}
1085 	mutex_enter(&sc->l2tp_lock);
1086 
1087 	ovar = sc->l2tp_var;
1088 	osrc = ovar->lv_psrc;
1089 	odst = ovar->lv_pdst;
1090 	*nvar = *ovar;
1091 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1092 	nvar->lv_psrc = NULL;
1093 	nvar->lv_pdst = NULL;
1094 	l2tp_variant_update(sc, nvar);
1095 
1096 	mutex_exit(&sc->l2tp_lock);
1097 
1098 	(void)l2tp_encap_detach(ovar);
1099 	encap_lock_exit();
1100 
1101 	if (osrc)
1102 		sockaddr_free(osrc);
1103 	if (odst)
1104 		sockaddr_free(odst);
1105 	kmem_free(ovar, sizeof(*ovar));
1106 }
1107 
1108 static int
id_hash_func(uint32_t id,u_long mask)1109 id_hash_func(uint32_t id, u_long mask)
1110 {
1111 	uint32_t hash;
1112 
1113 	hash = (id >> 16) ^ id;
1114 	hash = (hash >> 4) ^ hash;
1115 
1116 	return hash & mask;
1117 }
1118 
1119 static void
l2tp_hash_init(void)1120 l2tp_hash_init(void)
1121 {
1122 
1123 	l2tp_hash.lists = hashinit(L2TP_ID_HASH_SIZE, HASH_PSLIST, true,
1124 	    &l2tp_hash.mask);
1125 }
1126 
1127 static int
l2tp_hash_fini(void)1128 l2tp_hash_fini(void)
1129 {
1130 	int i;
1131 
1132 	mutex_enter(&l2tp_hash.lock);
1133 
1134 	for (i = 0; i < l2tp_hash.mask + 1; i++) {
1135 		if (PSLIST_WRITER_FIRST(&l2tp_hash.lists[i], struct l2tp_softc,
1136 			l2tp_hash) != NULL) {
1137 			mutex_exit(&l2tp_hash.lock);
1138 			return EBUSY;
1139 		}
1140 	}
1141 	for (i = 0; i < l2tp_hash.mask + 1; i++)
1142 		PSLIST_DESTROY(&l2tp_hash.lists[i]);
1143 
1144 	mutex_exit(&l2tp_hash.lock);
1145 
1146 	hashdone(l2tp_hash.lists, HASH_PSLIST, l2tp_hash.mask);
1147 
1148 	return 0;
1149 }
1150 
1151 static int
l2tp_set_session(struct l2tp_softc * sc,uint32_t my_sess_id,uint32_t peer_sess_id)1152 l2tp_set_session(struct l2tp_softc *sc, uint32_t my_sess_id,
1153     uint32_t peer_sess_id)
1154 {
1155 	uint32_t idx;
1156 	struct l2tp_variant *nvar;
1157 	struct l2tp_variant *ovar;
1158 	struct ifnet *ifp = &sc->l2tp_ec.ec_if;
1159 
1160 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1161 
1162 	mutex_enter(&sc->l2tp_lock);
1163 	ovar = sc->l2tp_var;
1164 	*nvar = *ovar;
1165 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1166 	nvar->lv_my_sess_id = my_sess_id;
1167 	nvar->lv_peer_sess_id = peer_sess_id;
1168 
1169 	mutex_enter(&l2tp_hash.lock);
1170 	if (ovar->lv_my_sess_id > 0 && ovar->lv_peer_sess_id > 0) {
1171 		PSLIST_WRITER_REMOVE(sc, l2tp_hash);
1172 		pserialize_perform(l2tp_psz);
1173 	}
1174 	mutex_exit(&l2tp_hash.lock);
1175 	PSLIST_ENTRY_DESTROY(sc, l2tp_hash);
1176 
1177 	l2tp_variant_update(sc, nvar);
1178 	mutex_exit(&sc->l2tp_lock);
1179 
1180 	idx = id_hash_func(nvar->lv_my_sess_id, l2tp_hash.mask);
1181 	if ((ifp->if_flags & IFF_DEBUG) != 0)
1182 		log(LOG_DEBUG, "%s: add hash entry: sess_id=%" PRIu32 ", idx=%" PRIu32 "\n",
1183 		    sc->l2tp_ec.ec_if.if_xname, nvar->lv_my_sess_id, idx);
1184 
1185 	PSLIST_ENTRY_INIT(sc, l2tp_hash);
1186 	mutex_enter(&l2tp_hash.lock);
1187 	PSLIST_WRITER_INSERT_HEAD(&l2tp_hash.lists[idx], sc, l2tp_hash);
1188 	mutex_exit(&l2tp_hash.lock);
1189 
1190 	kmem_free(ovar, sizeof(*ovar));
1191 	return 0;
1192 }
1193 
1194 static int
l2tp_clear_session(struct l2tp_softc * sc)1195 l2tp_clear_session(struct l2tp_softc *sc)
1196 {
1197 	struct l2tp_variant *nvar;
1198 	struct l2tp_variant *ovar;
1199 
1200 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1201 
1202 	mutex_enter(&sc->l2tp_lock);
1203 	ovar = sc->l2tp_var;
1204 	*nvar = *ovar;
1205 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1206 	nvar->lv_my_sess_id = 0;
1207 	nvar->lv_peer_sess_id = 0;
1208 
1209 	mutex_enter(&l2tp_hash.lock);
1210 	if (ovar->lv_my_sess_id > 0 && ovar->lv_peer_sess_id > 0) {
1211 		PSLIST_WRITER_REMOVE(sc, l2tp_hash);
1212 		pserialize_perform(l2tp_psz);
1213 	}
1214 	mutex_exit(&l2tp_hash.lock);
1215 
1216 	l2tp_variant_update(sc, nvar);
1217 	mutex_exit(&sc->l2tp_lock);
1218 	kmem_free(ovar, sizeof(*ovar));
1219 	return 0;
1220 }
1221 
1222 struct l2tp_variant *
l2tp_lookup_session_ref(uint32_t id,struct psref * psref)1223 l2tp_lookup_session_ref(uint32_t id, struct psref *psref)
1224 {
1225 	int idx;
1226 	int s;
1227 	struct l2tp_softc *sc;
1228 
1229 	idx = id_hash_func(id, l2tp_hash.mask);
1230 
1231 	s = pserialize_read_enter();
1232 	PSLIST_READER_FOREACH(sc, &l2tp_hash.lists[idx], struct l2tp_softc,
1233 	    l2tp_hash) {
1234 		struct l2tp_variant *var = atomic_load_consume(&sc->l2tp_var);
1235 		if (var == NULL)
1236 			continue;
1237 		if (var->lv_my_sess_id != id)
1238 			continue;
1239 		psref_acquire(psref, &var->lv_psref, lv_psref_class);
1240 		pserialize_read_exit(s);
1241 		return var;
1242 	}
1243 	pserialize_read_exit(s);
1244 	return NULL;
1245 }
1246 
1247 /*
1248  * l2tp_variant update API.
1249  *
1250  * Assumption:
1251  * reader side dereferences sc->l2tp_var in reader critical section only,
1252  * that is, all of reader sides do not reader the sc->l2tp_var after
1253  * pserialize_perform().
1254  */
1255 static void
l2tp_variant_update(struct l2tp_softc * sc,struct l2tp_variant * nvar)1256 l2tp_variant_update(struct l2tp_softc *sc, struct l2tp_variant *nvar)
1257 {
1258 	struct ifnet *ifp = &sc->l2tp_ec.ec_if;
1259 	struct l2tp_variant *ovar = sc->l2tp_var;
1260 
1261 	KASSERT(mutex_owned(&sc->l2tp_lock));
1262 
1263 	atomic_store_release(&sc->l2tp_var, nvar);
1264 	pserialize_perform(sc->l2tp_psz);
1265 	psref_target_destroy(&ovar->lv_psref, lv_psref_class);
1266 
1267 	if (nvar != NULL) {
1268 		if (nvar->lv_psrc != NULL && nvar->lv_pdst != NULL)
1269 			ifp->if_flags |= IFF_RUNNING;
1270 		else
1271 			ifp->if_flags &= ~IFF_RUNNING;
1272 	}
1273 }
1274 
1275 static int
l2tp_set_cookie(struct l2tp_softc * sc,uint64_t my_cookie,u_int my_cookie_len,uint64_t peer_cookie,u_int peer_cookie_len)1276 l2tp_set_cookie(struct l2tp_softc *sc, uint64_t my_cookie, u_int my_cookie_len,
1277     uint64_t peer_cookie, u_int peer_cookie_len)
1278 {
1279 	struct l2tp_variant *nvar;
1280 
1281 	if (my_cookie == 0 || peer_cookie == 0)
1282 		return EINVAL;
1283 
1284 	if (my_cookie_len != 4 && my_cookie_len != 8
1285 	    && peer_cookie_len != 4 && peer_cookie_len != 8)
1286 		return EINVAL;
1287 
1288 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1289 
1290 	mutex_enter(&sc->l2tp_lock);
1291 
1292 	*nvar = *sc->l2tp_var;
1293 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1294 	nvar->lv_my_cookie = my_cookie;
1295 	nvar->lv_my_cookie_len = my_cookie_len;
1296 	nvar->lv_peer_cookie = peer_cookie;
1297 	nvar->lv_peer_cookie_len = peer_cookie_len;
1298 	nvar->lv_use_cookie = L2TP_COOKIE_ON;
1299 	l2tp_variant_update(sc, nvar);
1300 
1301 	mutex_exit(&sc->l2tp_lock);
1302 
1303 	struct ifnet *ifp = &sc->l2tp_ec.ec_if;
1304 	if ((ifp->if_flags & IFF_DEBUG) != 0) {
1305 		log(LOG_DEBUG,
1306 		    "%s: set cookie: "
1307 		    "local cookie_len=%u local cookie=%" PRIu64 ", "
1308 		    "remote cookie_len=%u remote cookie=%" PRIu64 "\n",
1309 		    ifp->if_xname, my_cookie_len, my_cookie,
1310 		    peer_cookie_len, peer_cookie);
1311 	}
1312 
1313 	return 0;
1314 }
1315 
1316 static void
l2tp_clear_cookie(struct l2tp_softc * sc)1317 l2tp_clear_cookie(struct l2tp_softc *sc)
1318 {
1319 	struct l2tp_variant *nvar;
1320 
1321 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1322 
1323 	mutex_enter(&sc->l2tp_lock);
1324 
1325 	*nvar = *sc->l2tp_var;
1326 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1327 	nvar->lv_my_cookie = 0;
1328 	nvar->lv_my_cookie_len = 0;
1329 	nvar->lv_peer_cookie = 0;
1330 	nvar->lv_peer_cookie_len = 0;
1331 	nvar->lv_use_cookie = L2TP_COOKIE_OFF;
1332 	l2tp_variant_update(sc, nvar);
1333 
1334 	mutex_exit(&sc->l2tp_lock);
1335 }
1336 
1337 static void
l2tp_set_state(struct l2tp_softc * sc,int state)1338 l2tp_set_state(struct l2tp_softc *sc, int state)
1339 {
1340 	struct ifnet *ifp = &sc->l2tp_ec.ec_if;
1341 	struct l2tp_variant *nvar;
1342 	int ostate;
1343 
1344 	nvar = kmem_alloc(sizeof(*nvar), KM_SLEEP);
1345 
1346 	mutex_enter(&sc->l2tp_lock);
1347 
1348 	*nvar = *sc->l2tp_var;
1349 	psref_target_init(&nvar->lv_psref, lv_psref_class);
1350 	ostate = nvar->lv_state;
1351 	nvar->lv_state = state;
1352 	l2tp_variant_update(sc, nvar);
1353 	mutex_exit(&sc->l2tp_lock);
1354 
1355 	if (ostate != state) {
1356 		int lstate;
1357 
1358 		if (state == L2TP_STATE_UP)
1359 			lstate = LINK_STATE_UP;
1360 		else
1361 			lstate = LINK_STATE_DOWN;
1362 
1363 		if_link_state_change(ifp, lstate);
1364 	}
1365 
1366 #ifdef NOTYET
1367 	vlan_linkstate_notify(ifp, ifp->if_link_state);
1368 #endif
1369 }
1370 
1371 static int
l2tp_encap_attach(struct l2tp_variant * var)1372 l2tp_encap_attach(struct l2tp_variant *var)
1373 {
1374 	int error;
1375 
1376 	if (var == NULL || var->lv_psrc == NULL)
1377 		return EINVAL;
1378 
1379 	switch (var->lv_psrc->sa_family) {
1380 #ifdef INET
1381 	case AF_INET:
1382 		error = in_l2tp_attach(var);
1383 		break;
1384 #endif
1385 #ifdef INET6
1386 	case AF_INET6:
1387 		error = in6_l2tp_attach(var);
1388 		break;
1389 #endif
1390 	default:
1391 		error = EINVAL;
1392 		break;
1393 	}
1394 
1395 	return error;
1396 }
1397 
1398 static int
l2tp_encap_detach(struct l2tp_variant * var)1399 l2tp_encap_detach(struct l2tp_variant *var)
1400 {
1401 	int error;
1402 
1403 	if (var == NULL || var->lv_psrc == NULL)
1404 		return EINVAL;
1405 
1406 	switch (var->lv_psrc->sa_family) {
1407 #ifdef INET
1408 	case AF_INET:
1409 		error = in_l2tp_detach(var);
1410 		break;
1411 #endif
1412 #ifdef INET6
1413 	case AF_INET6:
1414 		error = in6_l2tp_detach(var);
1415 		break;
1416 #endif
1417 	default:
1418 		error = EINVAL;
1419 		break;
1420 	}
1421 
1422 	return error;
1423 }
1424 
1425 int
l2tp_check_nesting(struct ifnet * ifp,struct mbuf * m)1426 l2tp_check_nesting(struct ifnet *ifp, struct mbuf *m)
1427 {
1428 
1429 	return if_tunnel_check_nesting(ifp, m, max_l2tp_nesting);
1430 }
1431 
1432 /*
1433  * Module infrastructure
1434  */
1435 #include "if_module.h"
1436 
1437 IF_MODULE(MODULE_CLASS_DRIVER, l2tp, NULL)
1438 
1439 
1440 /* TODO: IP_TCPMSS support */
1441 #ifdef IP_TCPMSS
1442 static int l2tp_need_tcpmss_clamp(struct ifnet *);
1443 #ifdef INET
1444 static struct mbuf *l2tp_tcpmss4_clamp(struct ifnet *, struct mbuf *);
1445 #endif
1446 #ifdef INET6
1447 static struct mbuf *l2tp_tcpmss6_clamp(struct ifnet *, struct mbuf *);
1448 #endif
1449 
1450 struct mbuf *
l2tp_tcpmss_clamp(struct ifnet * ifp,struct mbuf * m)1451 l2tp_tcpmss_clamp(struct ifnet *ifp, struct mbuf *m)
1452 {
1453 	struct ether_header *eh;
1454 	struct ether_vlan_header evh;
1455 
1456 	if (!l2tp_need_tcpmss_clamp(ifp)) {
1457 		return m;
1458 	}
1459 
1460 	if (m->m_pkthdr.len < sizeof(evh)) {
1461 		m_freem(m);
1462 		return NULL;
1463 	}
1464 
1465 	/* save ether header */
1466 	m_copydata(m, 0, sizeof(evh), (void *)&evh);
1467 	eh = (struct ether_header *)&evh;
1468 
1469 	switch (ntohs(eh->ether_type)) {
1470 	case ETHERTYPE_VLAN: /* Ether + VLAN */
1471 		if (m->m_pkthdr.len <= sizeof(struct ether_vlan_header))
1472 			break;
1473 		m_adj(m, sizeof(struct ether_vlan_header));
1474 		switch (ntohs(evh.evl_proto)) {
1475 #ifdef INET
1476 		case ETHERTYPE_IP: /* Ether + VLAN + IPv4 */
1477 			m = l2tp_tcpmss4_clamp(ifp, m);
1478 			if (m == NULL)
1479 				return NULL;
1480 			break;
1481 #endif /* INET */
1482 #ifdef INET6
1483 		case ETHERTYPE_IPV6: /* Ether + VLAN + IPv6 */
1484 			m = l2tp_tcpmss6_clamp(ifp, m);
1485 			if (m == NULL)
1486 				return NULL;
1487 			break;
1488 #endif /* INET6 */
1489 		default:
1490 			break;
1491 		}
1492 
1493 		/* restore ether header */
1494 		M_PREPEND(m, sizeof(struct ether_vlan_header),
1495 		    M_DONTWAIT);
1496 		if (m == NULL)
1497 			return NULL;
1498 		*mtod(m, struct ether_vlan_header *) = evh;
1499 		break;
1500 
1501 #ifdef INET
1502 	case ETHERTYPE_IP: /* Ether + IPv4 */
1503 		if (m->m_pkthdr.len <= sizeof(struct ether_header))
1504 			break;
1505 		m_adj(m, sizeof(struct ether_header));
1506 		m = l2tp_tcpmss4_clamp(ifp, m);
1507 		if (m == NULL)
1508 			return NULL;
1509 		/* restore ether header */
1510 		M_PREPEND(m, sizeof(struct ether_header), M_DONTWAIT);
1511 		if (m == NULL)
1512 			return NULL;
1513 		*mtod(m, struct ether_header *) = *eh;
1514 		break;
1515 #endif /* INET */
1516 
1517 #ifdef INET6
1518 	case ETHERTYPE_IPV6: /* Ether + IPv6 */
1519 		if (m->m_pkthdr.len <= sizeof(struct ether_header))
1520 			break;
1521 		m_adj(m, sizeof(struct ether_header));
1522 		m = l2tp_tcpmss6_clamp(ifp, m);
1523 		if (m == NULL)
1524 			return NULL;
1525 		/* restore ether header */
1526 		M_PREPEND(m, sizeof(struct ether_header), M_DONTWAIT);
1527 		if (m == NULL)
1528 			return NULL;
1529 		*mtod(m, struct ether_header *) = *eh;
1530 		break;
1531 #endif /* INET6 */
1532 
1533 	default:
1534 		break;
1535 	}
1536 
1537 	return m;
1538 }
1539 
1540 static int
l2tp_need_tcpmss_clamp(struct ifnet * ifp)1541 l2tp_need_tcpmss_clamp(struct ifnet *ifp)
1542 {
1543 	int ret = 0;
1544 
1545 #ifdef INET
1546 	if (ifp->if_tcpmss != 0)
1547 		ret = 1;
1548 #endif
1549 
1550 #ifdef INET6
1551 	if (ifp->if_tcpmss6 != 0)
1552 		ret = 1;
1553 #endif
1554 
1555 	return ret;
1556 }
1557 
1558 #ifdef INET
1559 static struct mbuf *
l2tp_tcpmss4_clamp(struct ifnet * ifp,struct mbuf * m)1560 l2tp_tcpmss4_clamp(struct ifnet *ifp, struct mbuf *m)
1561 {
1562 
1563 	if (ifp->if_tcpmss != 0) {
1564 		return ip_tcpmss(m, (ifp->if_tcpmss < 0) ?
1565 			ifp->if_mtu - IP_TCPMSS_EXTLEN :
1566 			ifp->if_tcpmss);
1567 	}
1568 	return m;
1569 }
1570 #endif /* INET */
1571 
1572 #ifdef INET6
1573 static struct mbuf *
l2tp_tcpmss6_clamp(struct ifnet * ifp,struct mbuf * m)1574 l2tp_tcpmss6_clamp(struct ifnet *ifp, struct mbuf *m)
1575 {
1576 	int ip6hdrlen;
1577 
1578 	if (ifp->if_tcpmss6 != 0 &&
1579 	    ip6_tcpmss_applicable(m, &ip6hdrlen)) {
1580 		return ip6_tcpmss(m, ip6hdrlen,
1581 			(ifp->if_tcpmss6 < 0) ?
1582 			ifp->if_mtu - IP6_TCPMSS_EXTLEN :
1583 			ifp->if_tcpmss6);
1584 	}
1585 	return m;
1586 }
1587 #endif /* INET6 */
1588 
1589 #endif /* IP_TCPMSS */
1590