FreeBSD/Linux Kernel Cross Reference
sys/net/if_gre.c
1 /* $NetBSD: if_gre.c,v 1.42 2002/08/14 00:23:27 itojun Exp $ */
2 /* $FreeBSD$ */
3
4 /*
5 * Copyright (c) 1998 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Heiko W.Rupp <hwr@pilhuhn.de>
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 /*
41 * Encapsulate L3 protocols into IP
42 * See RFC 1701 and 1702 for more details.
43 * If_gre is compatible with Cisco GRE tunnels, so you can
44 * have a NetBSD box as the other end of a tunnel interface of a Cisco
45 * router. See gre(4) for more details.
46 * Also supported: IP in IP encaps (proto 55) as of RFC 2004
47 */
48
49 #include "opt_atalk.h"
50 #include "opt_inet.h"
51 #include "opt_ns.h"
52
53 #include <sys/param.h>
54 #include <sys/kernel.h>
55 #include <sys/malloc.h>
56 #include <sys/mbuf.h>
57 #include <sys/proc.h>
58 #include <sys/protosw.h>
59 #include <machine/bus.h>
60 #include <sys/rman.h>
61 #include <sys/socket.h>
62 #include <sys/sockio.h>
63 #include <sys/sysctl.h>
64 #include <sys/systm.h>
65
66 #include <net/ethernet.h>
67 #include <net/if.h>
68 #include <net/if_types.h>
69 #include <net/route.h>
70
71 #ifdef INET
72 #include <netinet/in.h>
73 #include <netinet/in_systm.h>
74 #include <netinet/in_var.h>
75 #include <netinet/ip.h>
76 #include <netinet/ip_gre.h>
77 #include <netinet/ip_var.h>
78 #include <netinet/ip_encap.h>
79 #else
80 #error "Huh? if_gre without inet?"
81 #endif
82
83 #include <net/bpf.h>
84
85 #include <net/net_osdep.h>
86 #include <net/if_gre.h>
87
88 /*
89 * It is not easy to calculate the right value for a GRE MTU.
90 * We leave this task to the admin and use the same default that
91 * other vendors use.
92 */
93 #define GREMTU 1476
94
95 #define GRENAME "gre"
96 #define GRE_MAXUNIT 0x7fff
97
98 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
99 static struct rman greunits[1];
100
101 struct gre_softc_head gre_softc_list;
102
103 static int gre_clone_create(struct if_clone *, int *);
104 static void gre_clone_destroy(struct ifnet *);
105 static int gre_ioctl(struct ifnet *, u_long, caddr_t);
106 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
107 struct rtentry *rt);
108
109 static struct if_clone gre_cloner =
110 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy);
111
112 static int gre_compute_route(struct gre_softc *sc);
113
114 static void greattach(void);
115
116 #ifdef INET
117 extern struct domain inetdomain;
118 static const struct protosw in_gre_protosw =
119 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR,
120 gre_input, rip_output, rip_ctlinput, rip_ctloutput,
121 0,
122 0, 0, 0, 0,
123 &rip_usrreqs
124 };
125 static const struct protosw in_mobile_protosw =
126 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR,
127 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput,
128 0,
129 0, 0, 0, 0,
130 &rip_usrreqs
131 };
132 #endif
133
134 SYSCTL_DECL(_net_link);
135 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0,
136 "Generic Routing Encapsulation");
137 #ifndef MAX_GRE_NEST
138 /*
139 * This macro controls the default upper limitation on nesting of gre tunnels.
140 * Since, setting a large value to this macro with a careless configuration
141 * may introduce system crash, we don't allow any nestings by default.
142 * If you need to configure nested gre tunnels, you can define this macro
143 * in your kernel configuration file. However, if you do so, please be
144 * careful to configure the tunnels so that it won't make a loop.
145 */
146 #define MAX_GRE_NEST 1
147 #endif
148 static int max_gre_nesting = MAX_GRE_NEST;
149 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
150 &max_gre_nesting, 0, "Max nested tunnels");
151
152 /* ARGSUSED */
153 static void
154 greattach(void)
155 {
156
157 LIST_INIT(&gre_softc_list);
158 if_clone_attach(&gre_cloner);
159 }
160
161 static int
162 gre_clone_create(ifc, unit)
163 struct if_clone *ifc;
164 int *unit;
165 {
166 struct resource *r;
167 struct gre_softc *sc;
168
169 if (*unit > GRE_MAXUNIT)
170 return (ENXIO);
171
172 if (*unit < 0) {
173 r = rman_reserve_resource(greunits, 0, GRE_MAXUNIT, 1,
174 RF_ALLOCATED | RF_ACTIVE, NULL);
175 if (r == NULL)
176 return (ENOSPC);
177 *unit = rman_get_start(r);
178 } else {
179 r = rman_reserve_resource(greunits, *unit, *unit, 1,
180 RF_ALLOCATED | RF_ACTIVE, NULL);
181 if (r == NULL)
182 return (EEXIST);
183 }
184
185 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
186 memset(sc, 0, sizeof(struct gre_softc));
187
188 sc->sc_if.if_name = GRENAME;
189 sc->sc_if.if_softc = sc;
190 sc->sc_if.if_unit = *unit;
191 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
192 sc->sc_if.if_type = IFT_OTHER;
193 sc->sc_if.if_addrlen = 0;
194 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
195 sc->sc_if.if_mtu = GREMTU;
196 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
197 sc->sc_if.if_output = gre_output;
198 sc->sc_if.if_ioctl = gre_ioctl;
199 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
200 sc->g_proto = IPPROTO_GRE;
201 sc->sc_if.if_flags |= IFF_LINK0;
202 sc->encap = NULL;
203 sc->called = 0;
204 sc->r_unit = r;
205 if_attach(&sc->sc_if);
206 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
207 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
208 return (0);
209 }
210
211 static void
212 gre_clone_destroy(ifp)
213 struct ifnet *ifp;
214 {
215 int err;
216 struct gre_softc *sc = ifp->if_softc;
217
218 #ifdef INET
219 if (sc->encap != NULL)
220 encap_detach(sc->encap);
221 #endif
222 LIST_REMOVE(sc, sc_list);
223 bpfdetach(ifp);
224 if_detach(ifp);
225
226 err = rman_release_resource(sc->r_unit);
227 KASSERT(err == 0, ("Unexpected error freeing resource"));
228
229 free(sc, M_GRE);
230 }
231
232 /*
233 * The output routine. Takes a packet and encapsulates it in the protocol
234 * given by sc->g_proto. See also RFC 1701 and RFC 2004
235 */
236 static int
237 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
238 struct rtentry *rt)
239 {
240 int error = 0;
241 struct gre_softc *sc = ifp->if_softc;
242 struct greip *gh;
243 struct ip *ip;
244 u_char osrc;
245 u_short etype = 0;
246 struct mobile_h mob_h;
247
248 /*
249 * gre may cause infinite recursion calls when misconfigured.
250 * We'll prevent this by introducing upper limit.
251 */
252 if (++(sc->called) > max_gre_nesting) {
253 printf("%s: gre_output: recursively called too many "
254 "times(%d)\n", if_name(&sc->sc_if), sc->called);
255 m_freem(m);
256 error = EIO; /* is there better errno? */
257 goto end;
258 }
259
260 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
261 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
262 m_freem(m);
263 error = ENETDOWN;
264 goto end;
265 }
266
267 gh = NULL;
268 ip = NULL;
269 osrc = 0;
270
271 if (ifp->if_bpf) {
272 /* see comment of other if_foo.c files */
273 struct mbuf m0;
274 u_int32_t af = dst->sa_family;
275
276 m0.m_next = m;
277 m0.m_len = 4;
278 m0.m_data = (char *)⁡
279
280 bpf_mtap(ifp, &m0);
281 }
282
283 m->m_flags &= ~(M_BCAST|M_MCAST);
284
285 if (sc->g_proto == IPPROTO_MOBILE) {
286 if (dst->sa_family == AF_INET) {
287 struct mbuf *m0;
288 int msiz;
289
290 ip = mtod(m, struct ip *);
291
292 /*
293 * RFC2004 specifies that fragmented diagrams shouldn't
294 * be encapsulated.
295 */
296 if ((ip->ip_off & IP_MF) != 0) {
297 IF_DROP(&ifp->if_snd);
298 m_freem(m);
299 error = EINVAL; /* is there better errno? */
300 goto end;
301 }
302 memset(&mob_h, 0, MOB_H_SIZ_L);
303 mob_h.proto = (ip->ip_p) << 8;
304 mob_h.odst = ip->ip_dst.s_addr;
305 ip->ip_dst.s_addr = sc->g_dst.s_addr;
306
307 /*
308 * If the packet comes from our host, we only change
309 * the destination address in the IP header.
310 * Else we also need to save and change the source
311 */
312 if (in_hosteq(ip->ip_src, sc->g_src)) {
313 msiz = MOB_H_SIZ_S;
314 } else {
315 mob_h.proto |= MOB_H_SBIT;
316 mob_h.osrc = ip->ip_src.s_addr;
317 ip->ip_src.s_addr = sc->g_src.s_addr;
318 msiz = MOB_H_SIZ_L;
319 }
320 mob_h.proto = htons(mob_h.proto);
321 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
322
323 if ((m->m_data - msiz) < m->m_pktdat) {
324 /* need new mbuf */
325 MGETHDR(m0, M_DONTWAIT, MT_HEADER);
326 if (m0 == NULL) {
327 IF_DROP(&ifp->if_snd);
328 m_freem(m);
329 error = ENOBUFS;
330 goto end;
331 }
332 m0->m_next = m;
333 m->m_data += sizeof(struct ip);
334 m->m_len -= sizeof(struct ip);
335 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
336 m0->m_len = msiz + sizeof(struct ip);
337 m0->m_data += max_linkhdr;
338 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
339 sizeof(struct ip));
340 m = m0;
341 } else { /* we have some space left in the old one */
342 m->m_data -= msiz;
343 m->m_len += msiz;
344 m->m_pkthdr.len += msiz;
345 bcopy(ip, mtod(m, caddr_t),
346 sizeof(struct ip));
347 }
348 ip = mtod(m, struct ip *);
349 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
350 ip->ip_len = ntohs(ip->ip_len) + msiz;
351 } else { /* AF_INET */
352 IF_DROP(&ifp->if_snd);
353 m_freem(m);
354 error = EINVAL;
355 goto end;
356 }
357 } else if (sc->g_proto == IPPROTO_GRE) {
358 switch (dst->sa_family) {
359 case AF_INET:
360 ip = mtod(m, struct ip *);
361 etype = ETHERTYPE_IP;
362 break;
363 #ifdef NETATALK
364 case AF_APPLETALK:
365 etype = ETHERTYPE_ATALK;
366 break;
367 #endif
368 #ifdef NS
369 case AF_NS:
370 etype = ETHERTYPE_NS;
371 break;
372 #endif
373 default:
374 IF_DROP(&ifp->if_snd);
375 m_freem(m);
376 error = EAFNOSUPPORT;
377 goto end;
378 }
379 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT);
380 } else {
381 IF_DROP(&ifp->if_snd);
382 m_freem(m);
383 error = EINVAL;
384 goto end;
385 }
386
387 if (m == NULL) { /* impossible */
388 IF_DROP(&ifp->if_snd);
389 error = ENOBUFS;
390 goto end;
391 }
392
393 gh = mtod(m, struct greip *);
394 if (sc->g_proto == IPPROTO_GRE) {
395 /* we don't have any GRE flags for now */
396
397 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
398 gh->gi_ptype = htons(etype);
399 }
400
401 gh->gi_pr = sc->g_proto;
402 if (sc->g_proto != IPPROTO_MOBILE) {
403 gh->gi_src = sc->g_src;
404 gh->gi_dst = sc->g_dst;
405 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
406 ((struct ip*)gh)->ip_ttl = GRE_TTL;
407 ((struct ip*)gh)->ip_tos = ip->ip_tos;
408 ((struct ip*)gh)->ip_id = ip->ip_id;
409 gh->gi_len = m->m_pkthdr.len;
410 }
411
412 ifp->if_opackets++;
413 ifp->if_obytes += m->m_pkthdr.len;
414 /* send it off */
415 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
416 end:
417 sc->called = 0;
418 if (error)
419 ifp->if_oerrors++;
420 return (error);
421 }
422
423 static int
424 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
425 {
426 struct ifreq *ifr = (struct ifreq *)data;
427 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
428 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
429 struct gre_softc *sc = ifp->if_softc;
430 int s;
431 struct sockaddr_in si;
432 struct sockaddr *sa = NULL;
433 int error;
434 struct sockaddr_in sp, sm, dp, dm;
435
436 error = 0;
437
438 s = splnet();
439 switch (cmd) {
440 case SIOCSIFADDR:
441 ifp->if_flags |= IFF_UP;
442 break;
443 case SIOCSIFDSTADDR:
444 break;
445 case SIOCSIFFLAGS:
446 if ((error = suser(curproc)) != 0)
447 break;
448 if ((ifr->ifr_flags & IFF_LINK0) != 0)
449 sc->g_proto = IPPROTO_GRE;
450 else
451 sc->g_proto = IPPROTO_MOBILE;
452 goto recompute;
453 case SIOCSIFMTU:
454 if ((error = suser(curproc)) != 0)
455 break;
456 if (ifr->ifr_mtu < 576) {
457 error = EINVAL;
458 break;
459 }
460 ifp->if_mtu = ifr->ifr_mtu;
461 break;
462 case SIOCGIFMTU:
463 ifr->ifr_mtu = sc->sc_if.if_mtu;
464 break;
465 case SIOCADDMULTI:
466 case SIOCDELMULTI:
467 if ((error = suser(curproc)) != 0)
468 break;
469 if (ifr == 0) {
470 error = EAFNOSUPPORT;
471 break;
472 }
473 switch (ifr->ifr_addr.sa_family) {
474 #ifdef INET
475 case AF_INET:
476 break;
477 #endif
478 default:
479 error = EAFNOSUPPORT;
480 break;
481 }
482 break;
483 case GRESPROTO:
484 if ((error = suser(curproc)) != 0)
485 break;
486 sc->g_proto = ifr->ifr_flags;
487 switch (sc->g_proto) {
488 case IPPROTO_GRE:
489 ifp->if_flags |= IFF_LINK0;
490 break;
491 case IPPROTO_MOBILE:
492 ifp->if_flags &= ~IFF_LINK0;
493 break;
494 default:
495 error = EPROTONOSUPPORT;
496 break;
497 }
498 goto recompute;
499 case GREGPROTO:
500 ifr->ifr_flags = sc->g_proto;
501 break;
502 case GRESADDRS:
503 case GRESADDRD:
504 if ((error = suser(curproc)) != 0)
505 break;
506 /*
507 * set tunnel endpoints, compute a less specific route
508 * to the remote end and mark if as up
509 */
510 sa = &ifr->ifr_addr;
511 if (cmd == GRESADDRS)
512 sc->g_src = (satosin(sa))->sin_addr;
513 if (cmd == GRESADDRD)
514 sc->g_dst = (satosin(sa))->sin_addr;
515 recompute:
516 #ifdef INET
517 if (sc->encap != NULL) {
518 encap_detach(sc->encap);
519 sc->encap = NULL;
520 }
521 #endif
522 if ((sc->g_src.s_addr != INADDR_ANY) &&
523 (sc->g_dst.s_addr != INADDR_ANY)) {
524 bzero(&sp, sizeof(sp));
525 bzero(&sm, sizeof(sm));
526 bzero(&dp, sizeof(dp));
527 bzero(&dm, sizeof(dm));
528 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
529 sizeof(struct sockaddr_in);
530 sp.sin_family = sm.sin_family = dp.sin_family =
531 dm.sin_family = AF_INET;
532 sp.sin_addr = sc->g_src;
533 dp.sin_addr = sc->g_dst;
534 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
535 INADDR_BROADCAST;
536 #ifdef INET
537 sc->encap = encap_attach(AF_INET, sc->g_proto,
538 sintosa(&sp), sintosa(&sm), sintosa(&dp),
539 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
540 &in_gre_protosw : &in_mobile_protosw, sc);
541 if (sc->encap == NULL)
542 printf("%s: unable to attach encap\n",
543 if_name(&sc->sc_if));
544 #endif
545 if (sc->route.ro_rt != 0) /* free old route */
546 RTFREE(sc->route.ro_rt);
547 if (gre_compute_route(sc) == 0)
548 ifp->if_flags |= IFF_RUNNING;
549 else
550 ifp->if_flags &= ~IFF_RUNNING;
551 }
552 break;
553 case GREGADDRS:
554 memset(&si, 0, sizeof(si));
555 si.sin_family = AF_INET;
556 si.sin_len = sizeof(struct sockaddr_in);
557 si.sin_addr.s_addr = sc->g_src.s_addr;
558 sa = sintosa(&si);
559 ifr->ifr_addr = *sa;
560 break;
561 case GREGADDRD:
562 memset(&si, 0, sizeof(si));
563 si.sin_family = AF_INET;
564 si.sin_len = sizeof(struct sockaddr_in);
565 si.sin_addr.s_addr = sc->g_dst.s_addr;
566 sa = sintosa(&si);
567 ifr->ifr_addr = *sa;
568 break;
569 case SIOCSIFPHYADDR:
570 if ((error = suser(curproc)) != 0)
571 break;
572 if (aifr->ifra_addr.sin_family != AF_INET ||
573 aifr->ifra_dstaddr.sin_family != AF_INET) {
574 error = EAFNOSUPPORT;
575 break;
576 }
577 if (aifr->ifra_addr.sin_len != sizeof(si) ||
578 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
579 error = EINVAL;
580 break;
581 }
582 sc->g_src = aifr->ifra_addr.sin_addr;
583 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
584 goto recompute;
585 case SIOCSLIFPHYADDR:
586 if ((error = suser(curproc)) != 0)
587 break;
588 if (lifr->addr.ss_family != AF_INET ||
589 lifr->dstaddr.ss_family != AF_INET) {
590 error = EAFNOSUPPORT;
591 break;
592 }
593 if (lifr->addr.ss_len != sizeof(si) ||
594 lifr->dstaddr.ss_len != sizeof(si)) {
595 error = EINVAL;
596 break;
597 }
598 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
599 sc->g_dst =
600 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
601 goto recompute;
602 case SIOCDIFPHYADDR:
603 if ((error = suser(curproc)) != 0)
604 break;
605 sc->g_src.s_addr = INADDR_ANY;
606 sc->g_dst.s_addr = INADDR_ANY;
607 goto recompute;
608 case SIOCGLIFPHYADDR:
609 if (sc->g_src.s_addr == INADDR_ANY ||
610 sc->g_dst.s_addr == INADDR_ANY) {
611 error = EADDRNOTAVAIL;
612 break;
613 }
614 memset(&si, 0, sizeof(si));
615 si.sin_family = AF_INET;
616 si.sin_len = sizeof(struct sockaddr_in);
617 si.sin_addr.s_addr = sc->g_src.s_addr;
618 memcpy(&lifr->addr, &si, sizeof(si));
619 si.sin_addr.s_addr = sc->g_dst.s_addr;
620 memcpy(&lifr->dstaddr, &si, sizeof(si));
621 break;
622 case SIOCGIFPSRCADDR:
623 if (sc->g_src.s_addr == INADDR_ANY) {
624 error = EADDRNOTAVAIL;
625 break;
626 }
627 memset(&si, 0, sizeof(si));
628 si.sin_family = AF_INET;
629 si.sin_len = sizeof(struct sockaddr_in);
630 si.sin_addr.s_addr = sc->g_src.s_addr;
631 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
632 break;
633 case SIOCGIFPDSTADDR:
634 if (sc->g_dst.s_addr == INADDR_ANY) {
635 error = EADDRNOTAVAIL;
636 break;
637 }
638 memset(&si, 0, sizeof(si));
639 si.sin_family = AF_INET;
640 si.sin_len = sizeof(struct sockaddr_in);
641 si.sin_addr.s_addr = sc->g_dst.s_addr;
642 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
643 break;
644 default:
645 error = EINVAL;
646 break;
647 }
648
649 splx(s);
650 return (error);
651 }
652
653 /*
654 * computes a route to our destination that is not the one
655 * which would be taken by ip_output(), as this one will loop back to
656 * us. If the interface is p2p as a--->b, then a routing entry exists
657 * If we now send a packet to b (e.g. ping b), this will come down here
658 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
659 * if_gre.
660 * Goal here is to compute a route to b that is less specific than
661 * a-->b. We know that this one exists as in normal operation we have
662 * at least a default route which matches.
663 */
664 static int
665 gre_compute_route(struct gre_softc *sc)
666 {
667 struct route *ro;
668 u_int32_t a, b, c;
669
670 ro = &sc->route;
671
672 memset(ro, 0, sizeof(struct route));
673 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
674 ro->ro_dst.sa_family = AF_INET;
675 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
676
677 /*
678 * toggle last bit, so our interface is not found, but a less
679 * specific route. I'd rather like to specify a shorter mask,
680 * but this is not possible. Should work though. XXX
681 * there is a simpler way ...
682 */
683 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
684 a = ntohl(sc->g_dst.s_addr);
685 b = a & 0x01;
686 c = a & 0xfffffffe;
687 b = b ^ 0x01;
688 a = b | c;
689 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
690 = htonl(a);
691 }
692
693 #ifdef DIAGNOSTIC
694 printf("%s: searching a route to %s", if_name(&sc->sc_if),
695 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
696 #endif
697
698 rtalloc(ro);
699
700 /*
701 * check if this returned a route at all and this route is no
702 * recursion to ourself
703 */
704 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
705 #ifdef DIAGNOSTIC
706 if (ro->ro_rt == NULL)
707 printf(" - no route found!\n");
708 else
709 printf(" - route loops back to ourself!\n");
710 #endif
711 return EADDRNOTAVAIL;
712 }
713
714 /*
715 * now change it back - else ip_output will just drop
716 * the route and search one to this interface ...
717 */
718 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
719 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
720
721 #ifdef DIAGNOSTIC
722 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
723 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
724 printf("\n");
725 #endif
726
727 return 0;
728 }
729
730 /*
731 * do a checksum of a buffer - much like in_cksum, which operates on
732 * mbufs.
733 */
734 u_short
735 gre_in_cksum(u_short *p, u_int len)
736 {
737 u_int sum = 0;
738 int nwords = len >> 1;
739
740 while (nwords-- != 0)
741 sum += *p++;
742
743 if (len & 1) {
744 union {
745 u_short w;
746 u_char c[2];
747 } u;
748 u.c[0] = *(u_char *)p;
749 u.c[1] = 0;
750 sum += u.w;
751 }
752
753 /* end-around-carry */
754 sum = (sum >> 16) + (sum & 0xffff);
755 sum += (sum >> 16);
756 return (~sum);
757 }
758
759 static int
760 gremodevent(module_t mod, int type, void *data)
761 {
762 int err;
763
764 switch (type) {
765 case MOD_LOAD:
766 greunits->rm_type = RMAN_ARRAY;
767 greunits->rm_descr = "configurable if_gre units";
768 err = rman_init(greunits);
769 if (err != 0)
770 return (err);
771 err = rman_manage_region(greunits, 0, GRE_MAXUNIT);
772 if (err != 0) {
773 printf("%s: greunits: rman_manage_region: Failed %d\n",
774 GRENAME, err);
775 rman_fini(greunits);
776 return (err);
777 }
778 greattach();
779 break;
780 case MOD_UNLOAD:
781 if_clone_detach(&gre_cloner);
782
783 while (!LIST_EMPTY(&gre_softc_list))
784 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
785
786 err = rman_fini(greunits);
787 if (err != 0)
788 return (err);
789
790 break;
791 }
792 return 0;
793 }
794
795 static moduledata_t gre_mod = {
796 "if_gre",
797 gremodevent,
798 0
799 };
800
801 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
802 MODULE_VERSION(if_gre, 1);
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