FreeBSD/Linux Kernel Cross Reference
sys/net/if_gre.c
1 /* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */
2 /* $FreeBSD: releng/5.3/sys/net/if_gre.c 136588 2004-10-16 08:43:07Z cvs2svn $ */
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_inet6.h"
52
53 #include <sys/param.h>
54 #include <sys/kernel.h>
55 #include <sys/malloc.h>
56 #include <sys/module.h>
57 #include <sys/mbuf.h>
58 #include <sys/protosw.h>
59 #include <sys/socket.h>
60 #include <sys/sockio.h>
61 #include <sys/sysctl.h>
62 #include <sys/systm.h>
63
64 #include <net/ethernet.h>
65 #include <net/if.h>
66 #include <net/if_clone.h>
67 #include <net/if_types.h>
68 #include <net/route.h>
69
70 #ifdef INET
71 #include <netinet/in.h>
72 #include <netinet/in_systm.h>
73 #include <netinet/in_var.h>
74 #include <netinet/ip.h>
75 #include <netinet/ip_gre.h>
76 #include <netinet/ip_var.h>
77 #include <netinet/ip_encap.h>
78 #else
79 #error "Huh? if_gre without inet?"
80 #endif
81
82 #include <net/bpf.h>
83
84 #include <net/net_osdep.h>
85 #include <net/if_gre.h>
86
87 /*
88 * It is not easy to calculate the right value for a GRE MTU.
89 * We leave this task to the admin and use the same default that
90 * other vendors use.
91 */
92 #define GREMTU 1476
93
94 #define GRENAME "gre"
95
96 /*
97 * gre_mtx protects all global variables in if_gre.c.
98 * XXX: gre_softc data not protected yet.
99 */
100 struct mtx gre_mtx;
101 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
102
103 struct gre_softc_head gre_softc_list;
104
105 static int gre_clone_create(struct if_clone *, int);
106 static void gre_clone_destroy(struct ifnet *);
107 static int gre_ioctl(struct ifnet *, u_long, caddr_t);
108 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
109 struct rtentry *rt);
110
111 IFC_SIMPLE_DECLARE(gre, 0);
112
113 static int gre_compute_route(struct gre_softc *sc);
114
115 static void greattach(void);
116
117 #ifdef INET
118 extern struct domain inetdomain;
119 static const struct protosw in_gre_protosw =
120 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR,
121 (pr_input_t*)gre_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput,
122 0,
123 0, 0, 0, 0,
124 &rip_usrreqs
125 };
126 static const struct protosw in_mobile_protosw =
127 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR,
128 (pr_input_t*)gre_mobile_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput,
129 0,
130 0, 0, 0, 0,
131 &rip_usrreqs
132 };
133 #endif
134
135 SYSCTL_DECL(_net_link);
136 SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0,
137 "Generic Routing Encapsulation");
138 #ifndef MAX_GRE_NEST
139 /*
140 * This macro controls the default upper limitation on nesting of gre tunnels.
141 * Since, setting a large value to this macro with a careless configuration
142 * may introduce system crash, we don't allow any nestings by default.
143 * If you need to configure nested gre tunnels, you can define this macro
144 * in your kernel configuration file. However, if you do so, please be
145 * careful to configure the tunnels so that it won't make a loop.
146 */
147 #define MAX_GRE_NEST 1
148 #endif
149 static int max_gre_nesting = MAX_GRE_NEST;
150 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
151 &max_gre_nesting, 0, "Max nested tunnels");
152
153 /* ARGSUSED */
154 static void
155 greattach(void)
156 {
157
158 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF);
159 LIST_INIT(&gre_softc_list);
160 if_clone_attach(&gre_cloner);
161 }
162
163 static int
164 gre_clone_create(ifc, unit)
165 struct if_clone *ifc;
166 int unit;
167 {
168 struct gre_softc *sc;
169
170 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO);
171
172 if_initname(&sc->sc_if, ifc->ifc_name, unit);
173 sc->sc_if.if_softc = sc;
174 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
175 sc->sc_if.if_type = IFT_TUNNEL;
176 sc->sc_if.if_addrlen = 0;
177 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
178 sc->sc_if.if_mtu = GREMTU;
179 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
180 sc->sc_if.if_output = gre_output;
181 sc->sc_if.if_ioctl = gre_ioctl;
182 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
183 sc->g_proto = IPPROTO_GRE;
184 sc->sc_if.if_flags |= IFF_LINK0;
185 sc->encap = NULL;
186 sc->called = 0;
187 sc->wccp_ver = WCCP_V1;
188 if_attach(&sc->sc_if);
189 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
190 mtx_lock(&gre_mtx);
191 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
192 mtx_unlock(&gre_mtx);
193 return (0);
194 }
195
196 static void
197 gre_destroy(struct gre_softc *sc)
198 {
199
200 #ifdef INET
201 if (sc->encap != NULL)
202 encap_detach(sc->encap);
203 #endif
204 bpfdetach(&sc->sc_if);
205 if_detach(&sc->sc_if);
206 free(sc, M_GRE);
207 }
208
209 static void
210 gre_clone_destroy(ifp)
211 struct ifnet *ifp;
212 {
213 struct gre_softc *sc = ifp->if_softc;
214
215 mtx_lock(&gre_mtx);
216 LIST_REMOVE(sc, sc_list);
217 mtx_unlock(&gre_mtx);
218 gre_destroy(sc);
219 }
220
221 /*
222 * The output routine. Takes a packet and encapsulates it in the protocol
223 * given by sc->g_proto. See also RFC 1701 and RFC 2004
224 */
225 static int
226 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
227 struct rtentry *rt)
228 {
229 int error = 0;
230 struct gre_softc *sc = ifp->if_softc;
231 struct greip *gh;
232 struct ip *ip;
233 u_int16_t etype = 0;
234 struct mobile_h mob_h;
235
236 /*
237 * gre may cause infinite recursion calls when misconfigured.
238 * We'll prevent this by introducing upper limit.
239 */
240 if (++(sc->called) > max_gre_nesting) {
241 printf("%s: gre_output: recursively called too many "
242 "times(%d)\n", if_name(&sc->sc_if), sc->called);
243 m_freem(m);
244 error = EIO; /* is there better errno? */
245 goto end;
246 }
247
248 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
249 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
250 m_freem(m);
251 error = ENETDOWN;
252 goto end;
253 }
254
255 gh = NULL;
256 ip = NULL;
257
258 if (ifp->if_bpf) {
259 u_int32_t af = dst->sa_family;
260 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
261 }
262
263 m->m_flags &= ~(M_BCAST|M_MCAST);
264
265 if (sc->g_proto == IPPROTO_MOBILE) {
266 if (dst->sa_family == AF_INET) {
267 struct mbuf *m0;
268 int msiz;
269
270 ip = mtod(m, struct ip *);
271
272 /*
273 * RFC2004 specifies that fragmented diagrams shouldn't
274 * be encapsulated.
275 */
276 if ((ip->ip_off & IP_MF) != 0) {
277 _IF_DROP(&ifp->if_snd);
278 m_freem(m);
279 error = EINVAL; /* is there better errno? */
280 goto end;
281 }
282 memset(&mob_h, 0, MOB_H_SIZ_L);
283 mob_h.proto = (ip->ip_p) << 8;
284 mob_h.odst = ip->ip_dst.s_addr;
285 ip->ip_dst.s_addr = sc->g_dst.s_addr;
286
287 /*
288 * If the packet comes from our host, we only change
289 * the destination address in the IP header.
290 * Else we also need to save and change the source
291 */
292 if (in_hosteq(ip->ip_src, sc->g_src)) {
293 msiz = MOB_H_SIZ_S;
294 } else {
295 mob_h.proto |= MOB_H_SBIT;
296 mob_h.osrc = ip->ip_src.s_addr;
297 ip->ip_src.s_addr = sc->g_src.s_addr;
298 msiz = MOB_H_SIZ_L;
299 }
300 mob_h.proto = htons(mob_h.proto);
301 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
302
303 if ((m->m_data - msiz) < m->m_pktdat) {
304 /* need new mbuf */
305 MGETHDR(m0, M_DONTWAIT, MT_HEADER);
306 if (m0 == NULL) {
307 _IF_DROP(&ifp->if_snd);
308 m_freem(m);
309 error = ENOBUFS;
310 goto end;
311 }
312 m0->m_next = m;
313 m->m_data += sizeof(struct ip);
314 m->m_len -= sizeof(struct ip);
315 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
316 m0->m_len = msiz + sizeof(struct ip);
317 m0->m_data += max_linkhdr;
318 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
319 sizeof(struct ip));
320 m = m0;
321 } else { /* we have some space left in the old one */
322 m->m_data -= msiz;
323 m->m_len += msiz;
324 m->m_pkthdr.len += msiz;
325 bcopy(ip, mtod(m, caddr_t),
326 sizeof(struct ip));
327 }
328 ip = mtod(m, struct ip *);
329 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
330 ip->ip_len = ntohs(ip->ip_len) + msiz;
331 } else { /* AF_INET */
332 _IF_DROP(&ifp->if_snd);
333 m_freem(m);
334 error = EINVAL;
335 goto end;
336 }
337 } else if (sc->g_proto == IPPROTO_GRE) {
338 switch (dst->sa_family) {
339 case AF_INET:
340 ip = mtod(m, struct ip *);
341 etype = ETHERTYPE_IP;
342 break;
343 #ifdef NETATALK
344 case AF_APPLETALK:
345 etype = ETHERTYPE_ATALK;
346 break;
347 #endif
348 default:
349 _IF_DROP(&ifp->if_snd);
350 m_freem(m);
351 error = EAFNOSUPPORT;
352 goto end;
353 }
354 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT);
355 } else {
356 _IF_DROP(&ifp->if_snd);
357 m_freem(m);
358 error = EINVAL;
359 goto end;
360 }
361
362 if (m == NULL) { /* mbuf allocation failed */
363 _IF_DROP(&ifp->if_snd);
364 error = ENOBUFS;
365 goto end;
366 }
367
368 gh = mtod(m, struct greip *);
369 if (sc->g_proto == IPPROTO_GRE) {
370 /* we don't have any GRE flags for now */
371 memset((void *)gh, 0, sizeof(struct greip));
372 gh->gi_ptype = htons(etype);
373 }
374
375 gh->gi_pr = sc->g_proto;
376 if (sc->g_proto != IPPROTO_MOBILE) {
377 gh->gi_src = sc->g_src;
378 gh->gi_dst = sc->g_dst;
379 ((struct ip*)gh)->ip_v = IPPROTO_IPV4;
380 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
381 ((struct ip*)gh)->ip_ttl = GRE_TTL;
382 ((struct ip*)gh)->ip_tos = ip->ip_tos;
383 ((struct ip*)gh)->ip_id = ip->ip_id;
384 gh->gi_len = m->m_pkthdr.len;
385 }
386
387 ifp->if_opackets++;
388 ifp->if_obytes += m->m_pkthdr.len;
389 /*
390 * Send it off and with IP_FORWARD flag to prevent it from
391 * overwriting the ip_id again. ip_id is already set to the
392 * ip_id of the encapsulated packet.
393 */
394 error = ip_output(m, NULL, &sc->route, IP_FORWARDING,
395 (struct ip_moptions *)NULL, (struct inpcb *)NULL);
396 end:
397 sc->called = 0;
398 if (error)
399 ifp->if_oerrors++;
400 return (error);
401 }
402
403 static int
404 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
405 {
406 struct ifreq *ifr = (struct ifreq *)data;
407 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
408 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
409 struct gre_softc *sc = ifp->if_softc;
410 int s;
411 struct sockaddr_in si;
412 struct sockaddr *sa = NULL;
413 int error;
414 struct sockaddr_in sp, sm, dp, dm;
415
416 error = 0;
417
418 s = splnet();
419 switch (cmd) {
420 case SIOCSIFADDR:
421 ifp->if_flags |= IFF_UP;
422 break;
423 case SIOCSIFDSTADDR:
424 break;
425 case SIOCSIFFLAGS:
426 if ((error = suser(curthread)) != 0)
427 break;
428 if ((ifr->ifr_flags & IFF_LINK0) != 0)
429 sc->g_proto = IPPROTO_GRE;
430 else
431 sc->g_proto = IPPROTO_MOBILE;
432 if ((ifr->ifr_flags & IFF_LINK2) != 0)
433 sc->wccp_ver = WCCP_V2;
434 else
435 sc->wccp_ver = WCCP_V1;
436 goto recompute;
437 case SIOCSIFMTU:
438 if ((error = suser(curthread)) != 0)
439 break;
440 if (ifr->ifr_mtu < 576) {
441 error = EINVAL;
442 break;
443 }
444 ifp->if_mtu = ifr->ifr_mtu;
445 break;
446 case SIOCGIFMTU:
447 ifr->ifr_mtu = sc->sc_if.if_mtu;
448 break;
449 case SIOCADDMULTI:
450 case SIOCDELMULTI:
451 if ((error = suser(curthread)) != 0)
452 break;
453 if (ifr == 0) {
454 error = EAFNOSUPPORT;
455 break;
456 }
457 switch (ifr->ifr_addr.sa_family) {
458 #ifdef INET
459 case AF_INET:
460 break;
461 #endif
462 default:
463 error = EAFNOSUPPORT;
464 break;
465 }
466 break;
467 case GRESPROTO:
468 if ((error = suser(curthread)) != 0)
469 break;
470 sc->g_proto = ifr->ifr_flags;
471 switch (sc->g_proto) {
472 case IPPROTO_GRE:
473 ifp->if_flags |= IFF_LINK0;
474 break;
475 case IPPROTO_MOBILE:
476 ifp->if_flags &= ~IFF_LINK0;
477 break;
478 default:
479 error = EPROTONOSUPPORT;
480 break;
481 }
482 goto recompute;
483 case GREGPROTO:
484 ifr->ifr_flags = sc->g_proto;
485 break;
486 case GRESADDRS:
487 case GRESADDRD:
488 if ((error = suser(curthread)) != 0)
489 break;
490 /*
491 * set tunnel endpoints, compute a less specific route
492 * to the remote end and mark if as up
493 */
494 sa = &ifr->ifr_addr;
495 if (cmd == GRESADDRS)
496 sc->g_src = (satosin(sa))->sin_addr;
497 if (cmd == GRESADDRD)
498 sc->g_dst = (satosin(sa))->sin_addr;
499 recompute:
500 #ifdef INET
501 if (sc->encap != NULL) {
502 encap_detach(sc->encap);
503 sc->encap = NULL;
504 }
505 #endif
506 if ((sc->g_src.s_addr != INADDR_ANY) &&
507 (sc->g_dst.s_addr != INADDR_ANY)) {
508 bzero(&sp, sizeof(sp));
509 bzero(&sm, sizeof(sm));
510 bzero(&dp, sizeof(dp));
511 bzero(&dm, sizeof(dm));
512 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
513 sizeof(struct sockaddr_in);
514 sp.sin_family = sm.sin_family = dp.sin_family =
515 dm.sin_family = AF_INET;
516 sp.sin_addr = sc->g_src;
517 dp.sin_addr = sc->g_dst;
518 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
519 INADDR_BROADCAST;
520 #ifdef INET
521 sc->encap = encap_attach(AF_INET, sc->g_proto,
522 sintosa(&sp), sintosa(&sm), sintosa(&dp),
523 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
524 &in_gre_protosw : &in_mobile_protosw, sc);
525 if (sc->encap == NULL)
526 printf("%s: unable to attach encap\n",
527 if_name(&sc->sc_if));
528 #endif
529 if (sc->route.ro_rt != 0) /* free old route */
530 RTFREE(sc->route.ro_rt);
531 if (gre_compute_route(sc) == 0)
532 ifp->if_flags |= IFF_RUNNING;
533 else
534 ifp->if_flags &= ~IFF_RUNNING;
535 }
536 break;
537 case GREGADDRS:
538 memset(&si, 0, sizeof(si));
539 si.sin_family = AF_INET;
540 si.sin_len = sizeof(struct sockaddr_in);
541 si.sin_addr.s_addr = sc->g_src.s_addr;
542 sa = sintosa(&si);
543 ifr->ifr_addr = *sa;
544 break;
545 case GREGADDRD:
546 memset(&si, 0, sizeof(si));
547 si.sin_family = AF_INET;
548 si.sin_len = sizeof(struct sockaddr_in);
549 si.sin_addr.s_addr = sc->g_dst.s_addr;
550 sa = sintosa(&si);
551 ifr->ifr_addr = *sa;
552 break;
553 case SIOCSIFPHYADDR:
554 if ((error = suser(curthread)) != 0)
555 break;
556 if (aifr->ifra_addr.sin_family != AF_INET ||
557 aifr->ifra_dstaddr.sin_family != AF_INET) {
558 error = EAFNOSUPPORT;
559 break;
560 }
561 if (aifr->ifra_addr.sin_len != sizeof(si) ||
562 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
563 error = EINVAL;
564 break;
565 }
566 sc->g_src = aifr->ifra_addr.sin_addr;
567 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
568 goto recompute;
569 case SIOCSLIFPHYADDR:
570 if ((error = suser(curthread)) != 0)
571 break;
572 if (lifr->addr.ss_family != AF_INET ||
573 lifr->dstaddr.ss_family != AF_INET) {
574 error = EAFNOSUPPORT;
575 break;
576 }
577 if (lifr->addr.ss_len != sizeof(si) ||
578 lifr->dstaddr.ss_len != sizeof(si)) {
579 error = EINVAL;
580 break;
581 }
582 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
583 sc->g_dst =
584 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
585 goto recompute;
586 case SIOCDIFPHYADDR:
587 if ((error = suser(curthread)) != 0)
588 break;
589 sc->g_src.s_addr = INADDR_ANY;
590 sc->g_dst.s_addr = INADDR_ANY;
591 goto recompute;
592 case SIOCGLIFPHYADDR:
593 if (sc->g_src.s_addr == INADDR_ANY ||
594 sc->g_dst.s_addr == INADDR_ANY) {
595 error = EADDRNOTAVAIL;
596 break;
597 }
598 memset(&si, 0, sizeof(si));
599 si.sin_family = AF_INET;
600 si.sin_len = sizeof(struct sockaddr_in);
601 si.sin_addr.s_addr = sc->g_src.s_addr;
602 memcpy(&lifr->addr, &si, sizeof(si));
603 si.sin_addr.s_addr = sc->g_dst.s_addr;
604 memcpy(&lifr->dstaddr, &si, sizeof(si));
605 break;
606 case SIOCGIFPSRCADDR:
607 #ifdef INET6
608 case SIOCGIFPSRCADDR_IN6:
609 #endif
610 if (sc->g_src.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 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
619 break;
620 case SIOCGIFPDSTADDR:
621 #ifdef INET6
622 case SIOCGIFPDSTADDR_IN6:
623 #endif
624 if (sc->g_dst.s_addr == INADDR_ANY) {
625 error = EADDRNOTAVAIL;
626 break;
627 }
628 memset(&si, 0, sizeof(si));
629 si.sin_family = AF_INET;
630 si.sin_len = sizeof(struct sockaddr_in);
631 si.sin_addr.s_addr = sc->g_dst.s_addr;
632 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
633 break;
634 default:
635 error = EINVAL;
636 break;
637 }
638
639 splx(s);
640 return (error);
641 }
642
643 /*
644 * computes a route to our destination that is not the one
645 * which would be taken by ip_output(), as this one will loop back to
646 * us. If the interface is p2p as a--->b, then a routing entry exists
647 * If we now send a packet to b (e.g. ping b), this will come down here
648 * gets src=a, dst=b tacked on and would from ip_output() sent back to
649 * if_gre.
650 * Goal here is to compute a route to b that is less specific than
651 * a-->b. We know that this one exists as in normal operation we have
652 * at least a default route which matches.
653 */
654 static int
655 gre_compute_route(struct gre_softc *sc)
656 {
657 struct route *ro;
658 u_int32_t a, b, c;
659
660 ro = &sc->route;
661
662 memset(ro, 0, sizeof(struct route));
663 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
664 ro->ro_dst.sa_family = AF_INET;
665 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
666
667 /*
668 * toggle last bit, so our interface is not found, but a less
669 * specific route. I'd rather like to specify a shorter mask,
670 * but this is not possible. Should work though. XXX
671 * there is a simpler way ...
672 */
673 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
674 a = ntohl(sc->g_dst.s_addr);
675 b = a & 0x01;
676 c = a & 0xfffffffe;
677 b = b ^ 0x01;
678 a = b | c;
679 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
680 = htonl(a);
681 }
682
683 #ifdef DIAGNOSTIC
684 printf("%s: searching for a route to %s", if_name(&sc->sc_if),
685 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
686 #endif
687
688 rtalloc(ro);
689
690 /*
691 * check if this returned a route at all and this route is no
692 * recursion to ourself
693 */
694 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
695 #ifdef DIAGNOSTIC
696 if (ro->ro_rt == NULL)
697 printf(" - no route found!\n");
698 else
699 printf(" - route loops back to ourself!\n");
700 #endif
701 return EADDRNOTAVAIL;
702 }
703
704 /*
705 * now change it back - else ip_output will just drop
706 * the route and search one to this interface ...
707 */
708 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
709 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
710
711 #ifdef DIAGNOSTIC
712 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
713 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
714 printf("\n");
715 #endif
716
717 return 0;
718 }
719
720 /*
721 * do a checksum of a buffer - much like in_cksum, which operates on
722 * mbufs.
723 */
724 u_int16_t
725 gre_in_cksum(u_int16_t *p, u_int len)
726 {
727 u_int32_t sum = 0;
728 int nwords = len >> 1;
729
730 while (nwords-- != 0)
731 sum += *p++;
732
733 if (len & 1) {
734 union {
735 u_short w;
736 u_char c[2];
737 } u;
738 u.c[0] = *(u_char *)p;
739 u.c[1] = 0;
740 sum += u.w;
741 }
742
743 /* end-around-carry */
744 sum = (sum >> 16) + (sum & 0xffff);
745 sum += (sum >> 16);
746 return (~sum);
747 }
748
749 static int
750 gremodevent(module_t mod, int type, void *data)
751 {
752 struct gre_softc *sc;
753
754 switch (type) {
755 case MOD_LOAD:
756 greattach();
757 break;
758 case MOD_UNLOAD:
759 if_clone_detach(&gre_cloner);
760
761 mtx_lock(&gre_mtx);
762 while ((sc = LIST_FIRST(&gre_softc_list)) != NULL) {
763 LIST_REMOVE(sc, sc_list);
764 mtx_unlock(&gre_mtx);
765 gre_destroy(sc);
766 mtx_lock(&gre_mtx);
767 }
768 mtx_unlock(&gre_mtx);
769 mtx_destroy(&gre_mtx);
770 break;
771 default:
772 return EOPNOTSUPP;
773 }
774 return 0;
775 }
776
777 static moduledata_t gre_mod = {
778 "if_gre",
779 gremodevent,
780 0
781 };
782
783 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
784 MODULE_VERSION(if_gre, 1);
Cache object: 9f0cf70858d9b92df1abcd26a223ecba
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