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 1.10 2004/06/02 14:42:58 eirikn 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>
66 #include <net/ethernet.h>
68 #include <net/if_types.h>
69 #include <net/route.h>
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>
80 #error "Huh? if_gre without inet?"
85 #include <net/net_osdep.h>
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
97 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
99 struct gre_softc_head gre_softc_list;
101 static int gre_clone_create(struct if_clone *, int);
102 static void gre_clone_destroy(struct ifnet *);
103 static int gre_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
104 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
107 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre",
108 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT);
110 static int gre_compute_route(struct gre_softc *sc);
112 static void greattach(void);
115 extern struct domain inetdomain;
116 static const struct protosw in_gre_protosw =
117 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR,
118 gre_input, rip_output, rip_ctlinput, rip_ctloutput,
123 static const struct protosw in_mobile_protosw =
124 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR,
125 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput,
132 SYSCTL_DECL(_net_link);
133 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0,
134 "Generic Routing Encapsulation");
137 * This macro controls the default upper limitation on nesting of gre tunnels.
138 * Since, setting a large value to this macro with a careless configuration
139 * may introduce system crash, we don't allow any nestings by default.
140 * If you need to configure nested gre tunnels, you can define this macro
141 * in your kernel configuration file. However, if you do so, please be
142 * careful to configure the tunnels so that it won't make a loop.
144 #define MAX_GRE_NEST 1
146 static int max_gre_nesting = MAX_GRE_NEST;
147 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
148 &max_gre_nesting, 0, "Max nested tunnels");
155 LIST_INIT(&gre_softc_list);
156 if_clone_attach(&gre_cloner);
160 gre_clone_create(ifc, unit)
161 struct if_clone *ifc;
164 struct gre_softc *sc;
166 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
167 memset(sc, 0, sizeof(struct gre_softc));
169 sc->sc_if.if_softc = sc;
170 if_initname(&(sc->sc_if), GRENAME, unit);
171 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
172 sc->sc_if.if_type = IFT_OTHER;
173 sc->sc_if.if_addrlen = 0;
174 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
175 sc->sc_if.if_mtu = GREMTU;
176 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
177 sc->sc_if.if_output = gre_output;
178 sc->sc_if.if_ioctl = gre_ioctl;
179 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
180 sc->g_proto = IPPROTO_GRE;
181 sc->sc_if.if_flags |= IFF_LINK0;
184 if_attach(&sc->sc_if);
185 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
186 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
191 gre_clone_destroy(ifp)
194 struct gre_softc *sc = ifp->if_softc;
197 if (sc->encap != NULL)
198 encap_detach(sc->encap);
200 LIST_REMOVE(sc, sc_list);
208 * The output routine. Takes a packet and encapsulates it in the protocol
209 * given by sc->g_proto. See also RFC 1701 and RFC 2004
212 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
216 struct gre_softc *sc = ifp->if_softc;
221 struct mobile_h mob_h;
224 * gre may cause infinite recursion calls when misconfigured.
225 * We'll prevent this by introducing upper limit.
227 if (++(sc->called) > max_gre_nesting) {
228 printf("%s: gre_output: recursively called too many "
229 "times(%d)\n", if_name(&sc->sc_if), sc->called);
231 error = EIO; /* is there better errno? */
235 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
236 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
247 /* see comment of other if_foo.c files */
249 u_int32_t af = dst->sa_family;
253 m0.m_data = (char *)⁡
258 m->m_flags &= ~(M_BCAST|M_MCAST);
260 if (sc->g_proto == IPPROTO_MOBILE) {
261 if (dst->sa_family == AF_INET) {
265 ip = mtod(m, struct ip *);
268 * RFC2004 specifies that fragmented diagrams shouldn't
271 if ((ip->ip_off & IP_MF) != 0) {
272 IF_DROP(&ifp->if_snd);
274 error = EINVAL; /* is there better errno? */
277 memset(&mob_h, 0, MOB_H_SIZ_L);
278 mob_h.proto = (ip->ip_p) << 8;
279 mob_h.odst = ip->ip_dst.s_addr;
280 ip->ip_dst.s_addr = sc->g_dst.s_addr;
283 * If the packet comes from our host, we only change
284 * the destination address in the IP header.
285 * Else we also need to save and change the source
287 if (in_hosteq(ip->ip_src, sc->g_src)) {
290 mob_h.proto |= MOB_H_SBIT;
291 mob_h.osrc = ip->ip_src.s_addr;
292 ip->ip_src.s_addr = sc->g_src.s_addr;
295 mob_h.proto = htons(mob_h.proto);
296 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
298 if ((m->m_data - msiz) < m->m_pktdat) {
300 MGETHDR(m0, MB_DONTWAIT, MT_HEADER);
302 IF_DROP(&ifp->if_snd);
308 m->m_data += sizeof(struct ip);
309 m->m_len -= sizeof(struct ip);
310 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
311 m0->m_len = msiz + sizeof(struct ip);
312 m0->m_data += max_linkhdr;
313 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
316 } else { /* we have some space left in the old one */
319 m->m_pkthdr.len += msiz;
320 bcopy(ip, mtod(m, caddr_t),
323 ip = mtod(m, struct ip *);
324 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
325 ip->ip_len = ntohs(ip->ip_len) + msiz;
326 } else { /* AF_INET */
327 IF_DROP(&ifp->if_snd);
332 } else if (sc->g_proto == IPPROTO_GRE) {
333 switch (dst->sa_family) {
335 ip = mtod(m, struct ip *);
336 etype = ETHERTYPE_IP;
340 etype = ETHERTYPE_ATALK;
345 etype = ETHERTYPE_NS;
349 IF_DROP(&ifp->if_snd);
351 error = EAFNOSUPPORT;
354 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT);
356 IF_DROP(&ifp->if_snd);
362 if (m == NULL) { /* impossible */
363 IF_DROP(&ifp->if_snd);
368 gh = mtod(m, struct greip *);
369 if (sc->g_proto == IPPROTO_GRE) {
370 /* we don't have any GRE flags for now */
372 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
373 gh->gi_ptype = htons(etype);
376 gh->gi_pr = sc->g_proto;
377 if (sc->g_proto != IPPROTO_MOBILE) {
378 gh->gi_src = sc->g_src;
379 gh->gi_dst = sc->g_dst;
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;
388 ifp->if_obytes += m->m_pkthdr.len;
390 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
399 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
401 struct ifreq *ifr = (struct ifreq *)data;
402 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
403 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
404 struct gre_softc *sc = ifp->if_softc;
406 struct sockaddr_in si;
407 struct sockaddr *sa = NULL;
409 struct sockaddr_in sp, sm, dp, dm;
416 ifp->if_flags |= IFF_UP;
421 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
423 if ((ifr->ifr_flags & IFF_LINK0) != 0)
424 sc->g_proto = IPPROTO_GRE;
426 sc->g_proto = IPPROTO_MOBILE;
429 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
431 if (ifr->ifr_mtu < 576) {
435 ifp->if_mtu = ifr->ifr_mtu;
438 ifr->ifr_mtu = sc->sc_if.if_mtu;
442 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
445 error = EAFNOSUPPORT;
448 switch (ifr->ifr_addr.sa_family) {
454 error = EAFNOSUPPORT;
459 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
461 sc->g_proto = ifr->ifr_flags;
462 switch (sc->g_proto) {
464 ifp->if_flags |= IFF_LINK0;
467 ifp->if_flags &= ~IFF_LINK0;
470 error = EPROTONOSUPPORT;
475 ifr->ifr_flags = sc->g_proto;
479 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
482 * set tunnel endpoints, compute a less specific route
483 * to the remote end and mark if as up
486 if (cmd == GRESADDRS)
487 sc->g_src = (satosin(sa))->sin_addr;
488 if (cmd == GRESADDRD)
489 sc->g_dst = (satosin(sa))->sin_addr;
492 if (sc->encap != NULL) {
493 encap_detach(sc->encap);
497 if ((sc->g_src.s_addr != INADDR_ANY) &&
498 (sc->g_dst.s_addr != INADDR_ANY)) {
499 bzero(&sp, sizeof(sp));
500 bzero(&sm, sizeof(sm));
501 bzero(&dp, sizeof(dp));
502 bzero(&dm, sizeof(dm));
503 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
504 sizeof(struct sockaddr_in);
505 sp.sin_family = sm.sin_family = dp.sin_family =
506 dm.sin_family = AF_INET;
507 sp.sin_addr = sc->g_src;
508 dp.sin_addr = sc->g_dst;
509 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
512 sc->encap = encap_attach(AF_INET, sc->g_proto,
513 sintosa(&sp), sintosa(&sm), sintosa(&dp),
514 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
515 &in_gre_protosw : &in_mobile_protosw, sc);
516 if (sc->encap == NULL)
517 printf("%s: unable to attach encap\n",
518 if_name(&sc->sc_if));
520 if (sc->route.ro_rt != 0) /* free old route */
521 RTFREE(sc->route.ro_rt);
522 if (gre_compute_route(sc) == 0)
523 ifp->if_flags |= IFF_RUNNING;
525 ifp->if_flags &= ~IFF_RUNNING;
529 memset(&si, 0, sizeof(si));
530 si.sin_family = AF_INET;
531 si.sin_len = sizeof(struct sockaddr_in);
532 si.sin_addr.s_addr = sc->g_src.s_addr;
537 memset(&si, 0, sizeof(si));
538 si.sin_family = AF_INET;
539 si.sin_len = sizeof(struct sockaddr_in);
540 si.sin_addr.s_addr = sc->g_dst.s_addr;
545 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
547 if (aifr->ifra_addr.sin_family != AF_INET ||
548 aifr->ifra_dstaddr.sin_family != AF_INET) {
549 error = EAFNOSUPPORT;
552 if (aifr->ifra_addr.sin_len != sizeof(si) ||
553 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
557 sc->g_src = aifr->ifra_addr.sin_addr;
558 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
560 case SIOCSLIFPHYADDR:
561 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
563 if (lifr->addr.ss_family != AF_INET ||
564 lifr->dstaddr.ss_family != AF_INET) {
565 error = EAFNOSUPPORT;
568 if (lifr->addr.ss_len != sizeof(si) ||
569 lifr->dstaddr.ss_len != sizeof(si)) {
573 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
575 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
578 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
580 sc->g_src.s_addr = INADDR_ANY;
581 sc->g_dst.s_addr = INADDR_ANY;
583 case SIOCGLIFPHYADDR:
584 if (sc->g_src.s_addr == INADDR_ANY ||
585 sc->g_dst.s_addr == INADDR_ANY) {
586 error = EADDRNOTAVAIL;
589 memset(&si, 0, sizeof(si));
590 si.sin_family = AF_INET;
591 si.sin_len = sizeof(struct sockaddr_in);
592 si.sin_addr.s_addr = sc->g_src.s_addr;
593 memcpy(&lifr->addr, &si, sizeof(si));
594 si.sin_addr.s_addr = sc->g_dst.s_addr;
595 memcpy(&lifr->dstaddr, &si, sizeof(si));
597 case SIOCGIFPSRCADDR:
598 if (sc->g_src.s_addr == INADDR_ANY) {
599 error = EADDRNOTAVAIL;
602 memset(&si, 0, sizeof(si));
603 si.sin_family = AF_INET;
604 si.sin_len = sizeof(struct sockaddr_in);
605 si.sin_addr.s_addr = sc->g_src.s_addr;
606 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
608 case SIOCGIFPDSTADDR:
609 if (sc->g_dst.s_addr == INADDR_ANY) {
610 error = EADDRNOTAVAIL;
613 memset(&si, 0, sizeof(si));
614 si.sin_family = AF_INET;
615 si.sin_len = sizeof(struct sockaddr_in);
616 si.sin_addr.s_addr = sc->g_dst.s_addr;
617 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
629 * computes a route to our destination that is not the one
630 * which would be taken by ip_output(), as this one will loop back to
631 * us. If the interface is p2p as a--->b, then a routing entry exists
632 * If we now send a packet to b (e.g. ping b), this will come down here
633 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
635 * Goal here is to compute a route to b that is less specific than
636 * a-->b. We know that this one exists as in normal operation we have
637 * at least a default route which matches.
640 gre_compute_route(struct gre_softc *sc)
647 memset(ro, 0, sizeof(struct route));
648 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
649 ro->ro_dst.sa_family = AF_INET;
650 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
653 * toggle last bit, so our interface is not found, but a less
654 * specific route. I'd rather like to specify a shorter mask,
655 * but this is not possible. Should work though. XXX
656 * there is a simpler way ...
658 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
659 a = ntohl(sc->g_dst.s_addr);
664 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
669 printf("%s: searching a route to %s", if_name(&sc->sc_if),
670 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
676 * check if this returned a route at all and this route is no
677 * recursion to ourself
679 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
681 if (ro->ro_rt == NULL)
682 printf(" - no route found!\n");
684 printf(" - route loops back to ourself!\n");
686 return EADDRNOTAVAIL;
690 * now change it back - else ip_output will just drop
691 * the route and search one to this interface ...
693 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
694 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
697 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
698 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
706 * do a checksum of a buffer - much like in_cksum, which operates on
710 gre_in_cksum(u_short *p, u_int len)
713 int nwords = len >> 1;
715 while (nwords-- != 0)
723 u.c[0] = *(u_char *)p;
728 /* end-around-carry */
729 sum = (sum >> 16) + (sum & 0xffff);
735 gremodevent(module_t mod, int type, void *data)
743 if_clone_detach(&gre_cloner);
745 while (!LIST_EMPTY(&gre_softc_list))
746 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
753 static moduledata_t gre_mod = {
759 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
760 MODULE_VERSION(if_gre, 1);