1 /* $NetBSD: if_gre.c,v 1.42 2002/08/14 00:23:27 itojun Exp $ */
2 /* $FreeBSD: src/sys/net/if_gre.c,v 1.9.2.3 2003/01/23 21:06:44 sam Exp $ */
3 /* $DragonFly: src/sys/net/gre/if_gre.c,v 1.17 2006/09/05 00:55:47 dillon Exp $ */
6 * Copyright (c) 1998 The NetBSD Foundation, Inc.
9 * This code is derived from software contributed to The NetBSD Foundation
10 * by Heiko W.Rupp <hwr@pilhuhn.de>
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the NetBSD
23 * Foundation, Inc. and its contributors.
24 * 4. Neither the name of The NetBSD Foundation nor the names of its
25 * contributors may be used to endorse or promote products derived
26 * from this software without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
42 * Encapsulate L3 protocols into IP
43 * See RFC 1701 and 1702 for more details.
44 * If_gre is compatible with Cisco GRE tunnels, so you can
45 * have a NetBSD box as the other end of a tunnel interface of a Cisco
46 * router. See gre(4) for more details.
47 * Also supported: IP in IP encaps (proto 55) as of RFC 2004
50 #include "opt_atalk.h"
54 #include <sys/param.h>
55 #include <sys/kernel.h>
56 #include <sys/malloc.h>
59 #include <sys/protosw.h>
60 #include <machine/bus.h>
61 #include <sys/socket.h>
62 #include <sys/sockio.h>
63 #include <sys/sysctl.h>
64 #include <sys/systm.h>
65 #include <sys/thread2.h>
67 #include <net/ethernet.h>
69 #include <net/if_types.h>
70 #include <net/route.h>
73 #include <netinet/in.h>
74 #include <netinet/in_systm.h>
75 #include <netinet/in_var.h>
76 #include <netinet/ip.h>
77 #include <netinet/ip_gre.h>
78 #include <netinet/ip_var.h>
79 #include <netinet/ip_encap.h>
81 #error "Huh? if_gre without inet?"
86 #include <net/net_osdep.h>
90 * It is not easy to calculate the right value for a GRE MTU.
91 * We leave this task to the admin and use the same default that
98 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
100 struct gre_softc_head gre_softc_list;
102 static int gre_clone_create(struct if_clone *, int);
103 static void gre_clone_destroy(struct ifnet *);
104 static int gre_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
105 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
108 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre",
109 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT);
111 static int gre_compute_route(struct gre_softc *sc);
113 static void greattach(void);
116 extern struct domain inetdomain;
117 static const struct protosw in_gre_protosw =
118 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR,
119 gre_input, rip_output, rip_ctlinput, rip_ctloutput,
124 static const struct protosw in_mobile_protosw =
125 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR,
126 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput,
133 SYSCTL_DECL(_net_link);
134 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0,
135 "Generic Routing Encapsulation");
138 * This macro controls the default upper limitation on nesting of gre tunnels.
139 * Since, setting a large value to this macro with a careless configuration
140 * may introduce system crash, we don't allow any nestings by default.
141 * If you need to configure nested gre tunnels, you can define this macro
142 * in your kernel configuration file. However, if you do so, please be
143 * careful to configure the tunnels so that it won't make a loop.
145 #define MAX_GRE_NEST 1
147 static int max_gre_nesting = MAX_GRE_NEST;
148 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
149 &max_gre_nesting, 0, "Max nested tunnels");
156 LIST_INIT(&gre_softc_list);
157 if_clone_attach(&gre_cloner);
161 gre_clone_create(struct if_clone *ifc, int unit)
163 struct gre_softc *sc;
165 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
166 memset(sc, 0, sizeof(struct gre_softc));
168 sc->sc_if.if_softc = sc;
169 if_initname(&(sc->sc_if), GRENAME, unit);
170 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
171 sc->sc_if.if_type = IFT_OTHER;
172 sc->sc_if.if_addrlen = 0;
173 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
174 sc->sc_if.if_mtu = GREMTU;
175 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
176 sc->sc_if.if_output = gre_output;
177 sc->sc_if.if_ioctl = gre_ioctl;
178 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
179 sc->g_proto = IPPROTO_GRE;
180 sc->sc_if.if_flags |= IFF_LINK0;
183 if_attach(&sc->sc_if, NULL);
184 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
185 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
190 gre_clone_destroy(struct ifnet *ifp)
192 struct gre_softc *sc = ifp->if_softc;
195 if (sc->encap != NULL)
196 encap_detach(sc->encap);
198 LIST_REMOVE(sc, sc_list);
206 * The output routine. Takes a packet and encapsulates it in the protocol
207 * given by sc->g_proto. See also RFC 1701 and RFC 2004
210 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
214 struct gre_softc *sc = ifp->if_softc;
219 struct mobile_h mob_h;
222 * gre may cause infinite recursion calls when misconfigured.
223 * We'll prevent this by introducing upper limit.
225 if (++(sc->called) > max_gre_nesting) {
226 printf("%s: gre_output: recursively called too many "
227 "times(%d)\n", if_name(&sc->sc_if), sc->called);
229 error = EIO; /* is there better errno? */
233 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
234 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
245 uint32_t af = dst->sa_family;
247 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
250 m->m_flags &= ~(M_BCAST|M_MCAST);
252 if (sc->g_proto == IPPROTO_MOBILE) {
253 if (dst->sa_family == AF_INET) {
257 ip = mtod(m, struct ip *);
260 * RFC2004 specifies that fragmented datagrams shouldn't
263 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
264 IF_DROP(&ifp->if_snd);
266 error = EINVAL; /* is there better errno? */
269 memset(&mob_h, 0, MOB_H_SIZ_L);
270 mob_h.proto = (ip->ip_p) << 8;
271 mob_h.odst = ip->ip_dst.s_addr;
272 ip->ip_dst.s_addr = sc->g_dst.s_addr;
275 * If the packet comes from our host, we only change
276 * the destination address in the IP header.
277 * Else we also need to save and change the source
279 if (in_hosteq(ip->ip_src, sc->g_src)) {
282 mob_h.proto |= MOB_H_SBIT;
283 mob_h.osrc = ip->ip_src.s_addr;
284 ip->ip_src.s_addr = sc->g_src.s_addr;
287 mob_h.proto = htons(mob_h.proto);
288 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
290 if ((m->m_data - msiz) < m->m_pktdat) {
292 MGETHDR(m0, MB_DONTWAIT, MT_HEADER);
294 IF_DROP(&ifp->if_snd);
300 m->m_data += sizeof(struct ip);
301 m->m_len -= sizeof(struct ip);
302 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
303 m0->m_len = msiz + sizeof(struct ip);
304 m0->m_data += max_linkhdr;
305 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
308 } else { /* we have some space left in the old one */
311 m->m_pkthdr.len += msiz;
312 bcopy(ip, mtod(m, caddr_t),
315 ip = mtod(m, struct ip *);
316 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
317 ip->ip_len = ntohs(ip->ip_len) + msiz;
318 } else { /* AF_INET */
319 IF_DROP(&ifp->if_snd);
324 } else if (sc->g_proto == IPPROTO_GRE) {
325 switch (dst->sa_family) {
327 ip = mtod(m, struct ip *);
328 etype = ETHERTYPE_IP;
332 etype = ETHERTYPE_ATALK;
337 etype = ETHERTYPE_NS;
341 IF_DROP(&ifp->if_snd);
343 error = EAFNOSUPPORT;
346 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT);
348 IF_DROP(&ifp->if_snd);
354 if (m == NULL) { /* impossible */
355 IF_DROP(&ifp->if_snd);
360 gh = mtod(m, struct greip *);
361 if (sc->g_proto == IPPROTO_GRE) {
362 /* we don't have any GRE flags for now */
364 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
365 gh->gi_ptype = htons(etype);
368 gh->gi_pr = sc->g_proto;
369 if (sc->g_proto != IPPROTO_MOBILE) {
370 gh->gi_src = sc->g_src;
371 gh->gi_dst = sc->g_dst;
372 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
373 ((struct ip*)gh)->ip_ttl = GRE_TTL;
374 ((struct ip*)gh)->ip_tos = ip->ip_tos;
375 ((struct ip*)gh)->ip_id = ip->ip_id;
376 gh->gi_len = m->m_pkthdr.len;
380 ifp->if_obytes += m->m_pkthdr.len;
382 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
391 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
393 struct ifreq *ifr = (struct ifreq *)data;
394 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
395 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
396 struct gre_softc *sc = ifp->if_softc;
397 struct sockaddr_in si;
398 struct sockaddr *sa = NULL;
400 struct sockaddr_in sp, sm, dp, dm;
407 ifp->if_flags |= IFF_UP;
412 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
414 if ((ifr->ifr_flags & IFF_LINK0) != 0)
415 sc->g_proto = IPPROTO_GRE;
417 sc->g_proto = IPPROTO_MOBILE;
420 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
422 if (ifr->ifr_mtu < 576) {
426 ifp->if_mtu = ifr->ifr_mtu;
429 ifr->ifr_mtu = sc->sc_if.if_mtu;
433 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
436 error = EAFNOSUPPORT;
439 switch (ifr->ifr_addr.sa_family) {
445 error = EAFNOSUPPORT;
450 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
452 sc->g_proto = ifr->ifr_flags;
453 switch (sc->g_proto) {
455 ifp->if_flags |= IFF_LINK0;
458 ifp->if_flags &= ~IFF_LINK0;
461 error = EPROTONOSUPPORT;
466 ifr->ifr_flags = sc->g_proto;
470 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
473 * set tunnel endpoints, compute a less specific route
474 * to the remote end and mark if as up
477 if (cmd == GRESADDRS)
478 sc->g_src = (satosin(sa))->sin_addr;
479 if (cmd == GRESADDRD)
480 sc->g_dst = (satosin(sa))->sin_addr;
483 if (sc->encap != NULL) {
484 encap_detach(sc->encap);
488 if ((sc->g_src.s_addr != INADDR_ANY) &&
489 (sc->g_dst.s_addr != INADDR_ANY)) {
490 bzero(&sp, sizeof(sp));
491 bzero(&sm, sizeof(sm));
492 bzero(&dp, sizeof(dp));
493 bzero(&dm, sizeof(dm));
494 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
495 sizeof(struct sockaddr_in);
496 sp.sin_family = sm.sin_family = dp.sin_family =
497 dm.sin_family = AF_INET;
498 sp.sin_addr = sc->g_src;
499 dp.sin_addr = sc->g_dst;
500 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
503 sc->encap = encap_attach(AF_INET, sc->g_proto,
504 sintosa(&sp), sintosa(&sm), sintosa(&dp),
505 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
506 &in_gre_protosw : &in_mobile_protosw, sc);
507 if (sc->encap == NULL)
508 printf("%s: unable to attach encap\n",
509 if_name(&sc->sc_if));
511 if (sc->route.ro_rt != 0) /* free old route */
512 RTFREE(sc->route.ro_rt);
513 if (gre_compute_route(sc) == 0)
514 ifp->if_flags |= IFF_RUNNING;
516 ifp->if_flags &= ~IFF_RUNNING;
520 memset(&si, 0, sizeof(si));
521 si.sin_family = AF_INET;
522 si.sin_len = sizeof(struct sockaddr_in);
523 si.sin_addr.s_addr = sc->g_src.s_addr;
528 memset(&si, 0, sizeof(si));
529 si.sin_family = AF_INET;
530 si.sin_len = sizeof(struct sockaddr_in);
531 si.sin_addr.s_addr = sc->g_dst.s_addr;
536 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
538 if (aifr->ifra_addr.sin_family != AF_INET ||
539 aifr->ifra_dstaddr.sin_family != AF_INET) {
540 error = EAFNOSUPPORT;
543 if (aifr->ifra_addr.sin_len != sizeof(si) ||
544 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
548 sc->g_src = aifr->ifra_addr.sin_addr;
549 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
551 case SIOCSLIFPHYADDR:
552 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
554 if (lifr->addr.ss_family != AF_INET ||
555 lifr->dstaddr.ss_family != AF_INET) {
556 error = EAFNOSUPPORT;
559 if (lifr->addr.ss_len != sizeof(si) ||
560 lifr->dstaddr.ss_len != sizeof(si)) {
564 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
566 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
569 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
571 sc->g_src.s_addr = INADDR_ANY;
572 sc->g_dst.s_addr = INADDR_ANY;
574 case SIOCGLIFPHYADDR:
575 if (sc->g_src.s_addr == INADDR_ANY ||
576 sc->g_dst.s_addr == INADDR_ANY) {
577 error = EADDRNOTAVAIL;
580 memset(&si, 0, sizeof(si));
581 si.sin_family = AF_INET;
582 si.sin_len = sizeof(struct sockaddr_in);
583 si.sin_addr.s_addr = sc->g_src.s_addr;
584 memcpy(&lifr->addr, &si, sizeof(si));
585 si.sin_addr.s_addr = sc->g_dst.s_addr;
586 memcpy(&lifr->dstaddr, &si, sizeof(si));
588 case SIOCGIFPSRCADDR:
589 if (sc->g_src.s_addr == INADDR_ANY) {
590 error = EADDRNOTAVAIL;
593 memset(&si, 0, sizeof(si));
594 si.sin_family = AF_INET;
595 si.sin_len = sizeof(struct sockaddr_in);
596 si.sin_addr.s_addr = sc->g_src.s_addr;
597 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
599 case SIOCGIFPDSTADDR:
600 if (sc->g_dst.s_addr == INADDR_ANY) {
601 error = EADDRNOTAVAIL;
604 memset(&si, 0, sizeof(si));
605 si.sin_family = AF_INET;
606 si.sin_len = sizeof(struct sockaddr_in);
607 si.sin_addr.s_addr = sc->g_dst.s_addr;
608 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
620 * computes a route to our destination that is not the one
621 * which would be taken by ip_output(), as this one will loop back to
622 * us. If the interface is p2p as a--->b, then a routing entry exists
623 * If we now send a packet to b (e.g. ping b), this will come down here
624 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
626 * Goal here is to compute a route to b that is less specific than
627 * a-->b. We know that this one exists as in normal operation we have
628 * at least a default route which matches.
631 gre_compute_route(struct gre_softc *sc)
638 memset(ro, 0, sizeof(struct route));
639 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
640 ro->ro_dst.sa_family = AF_INET;
641 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
644 * toggle last bit, so our interface is not found, but a less
645 * specific route. I'd rather like to specify a shorter mask,
646 * but this is not possible. Should work though. XXX
647 * there is a simpler way ...
649 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
650 a = ntohl(sc->g_dst.s_addr);
655 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
660 printf("%s: searching a route to %s", if_name(&sc->sc_if),
661 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
667 * check if this returned a route at all and this route is no
668 * recursion to ourself
670 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
672 if (ro->ro_rt == NULL)
673 printf(" - no route found!\n");
675 printf(" - route loops back to ourself!\n");
677 return EADDRNOTAVAIL;
681 * now change it back - else ip_output will just drop
682 * the route and search one to this interface ...
684 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
685 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
688 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
689 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
697 * do a checksum of a buffer - much like in_cksum, which operates on
701 gre_in_cksum(u_short *p, u_int len)
704 int nwords = len >> 1;
706 while (nwords-- != 0)
714 u.c[0] = *(u_char *)p;
719 /* end-around-carry */
720 sum = (sum >> 16) + (sum & 0xffff);
726 gremodevent(module_t mod, int type, void *data)
734 if_clone_detach(&gre_cloner);
736 while (!LIST_EMPTY(&gre_softc_list))
737 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
744 static moduledata_t gre_mod = {
750 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
751 MODULE_VERSION(if_gre, 1);