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 $ */
5 * Copyright (c) 1998 The NetBSD Foundation, Inc.
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Heiko W.Rupp <hwr@pilhuhn.de>
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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.
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
49 #include "opt_atalk.h"
52 #include <sys/param.h>
53 #include <sys/kernel.h>
55 #include <sys/malloc.h>
59 #include <sys/protosw.h>
60 #include <sys/socket.h>
61 #include <sys/sockio.h>
62 #include <sys/sysctl.h>
63 #include <sys/systm.h>
64 #include <sys/thread2.h>
66 #include <net/ethernet.h>
68 #include <net/if_types.h>
69 #include <net/route.h>
70 #include <net/if_clone.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, caddr_t);
103 static int 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);
117 extern struct domain inetdomain;
119 static const struct protosw in_gre_protosw =
122 .pr_domain = &inetdomain,
123 .pr_protocol = IPPROTO_GRE,
124 .pr_flags = PR_ATOMIC|PR_ADDR,
126 .pr_input = gre_input,
127 .pr_output = rip_output,
128 .pr_ctlinput = rip_ctlinput,
129 .pr_ctloutput = rip_ctloutput,
131 .pr_ctlport = cpu0_ctlport,
132 .pr_usrreqs = &rip_usrreqs
135 static const struct protosw in_mobile_protosw =
138 .pr_domain = &inetdomain,
139 .pr_protocol = IPPROTO_MOBILE,
140 .pr_flags = PR_ATOMIC|PR_ADDR,
142 .pr_input = gre_mobile_input,
143 .pr_output = rip_output,
144 .pr_ctlinput = rip_ctlinput,
145 .pr_ctloutput = rip_ctloutput,
147 .pr_ctlport = cpu0_ctlport,
148 .pr_usrreqs = &rip_usrreqs
153 SYSCTL_DECL(_net_link);
154 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0,
155 "Generic Routing Encapsulation");
158 * This macro controls the default upper limitation on nesting of gre tunnels.
159 * Since, setting a large value to this macro with a careless configuration
160 * may introduce system crash, we don't allow any nestings by default.
161 * If you need to configure nested gre tunnels, you can define this macro
162 * in your kernel configuration file. However, if you do so, please be
163 * careful to configure the tunnels so that it won't make a loop.
165 #define MAX_GRE_NEST 1
167 static int max_gre_nesting = MAX_GRE_NEST;
168 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
169 &max_gre_nesting, 0, "Max nested tunnels");
176 LIST_INIT(&gre_softc_list);
177 if_clone_attach(&gre_cloner);
181 gre_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused)
183 struct gre_softc *sc;
185 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
186 memset(sc, 0, sizeof(struct gre_softc));
188 sc->sc_if.if_softc = sc;
189 if_initname(&(sc->sc_if), GRENAME, unit);
190 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
191 sc->sc_if.if_type = IFT_OTHER;
192 sc->sc_if.if_addrlen = 0;
193 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
194 sc->sc_if.if_mtu = GREMTU;
195 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
196 sc->sc_if.if_output = gre_output;
197 sc->sc_if.if_ioctl = gre_ioctl;
198 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
199 sc->g_proto = IPPROTO_GRE;
200 sc->sc_if.if_flags |= IFF_LINK0;
203 if_attach(&sc->sc_if, NULL);
204 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
205 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
210 gre_clone_destroy(struct ifnet *ifp)
212 struct gre_softc *sc = ifp->if_softc;
215 if (sc->encap != NULL)
216 encap_detach(sc->encap);
218 LIST_REMOVE(sc, sc_list);
228 * The output routine. Takes a packet and encapsulates it in the protocol
229 * given by sc->g_proto. See also RFC 1701 and RFC 2004
232 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
236 struct gre_softc *sc = ifp->if_softc;
241 struct mobile_h mob_h;
244 * gre may cause infinite recursion calls when misconfigured.
245 * We'll prevent this by introducing upper limit.
247 if (++(sc->called) > max_gre_nesting) {
248 kprintf("%s: gre_output: recursively called too many "
249 "times(%d)\n", if_name(&sc->sc_if), sc->called);
251 error = EIO; /* is there better errno? */
255 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
256 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
267 uint32_t af = dst->sa_family;
269 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
272 m->m_flags &= ~(M_BCAST|M_MCAST);
274 if (sc->g_proto == IPPROTO_MOBILE) {
275 if (dst->sa_family == AF_INET) {
279 ip = mtod(m, struct ip *);
282 * RFC2004 specifies that fragmented datagrams shouldn't
285 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
286 IF_DROP(&ifp->if_snd);
288 error = EINVAL; /* is there better errno? */
291 memset(&mob_h, 0, MOB_H_SIZ_L);
292 mob_h.proto = (ip->ip_p) << 8;
293 mob_h.odst = ip->ip_dst.s_addr;
294 ip->ip_dst.s_addr = sc->g_dst.s_addr;
297 * If the packet comes from our host, we only change
298 * the destination address in the IP header.
299 * Else we also need to save and change the source
301 if (in_hosteq(ip->ip_src, sc->g_src)) {
304 mob_h.proto |= MOB_H_SBIT;
305 mob_h.osrc = ip->ip_src.s_addr;
306 ip->ip_src.s_addr = sc->g_src.s_addr;
309 mob_h.proto = htons(mob_h.proto);
310 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
312 if ((m->m_data - msiz) < m->m_pktdat) {
314 MGETHDR(m0, MB_DONTWAIT, MT_HEADER);
316 IF_DROP(&ifp->if_snd);
322 m->m_data += sizeof(struct ip);
323 m->m_len -= sizeof(struct ip);
324 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
325 m0->m_len = msiz + sizeof(struct ip);
326 m0->m_data += max_linkhdr;
327 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
330 } else { /* we have some space left in the old one */
333 m->m_pkthdr.len += msiz;
334 bcopy(ip, mtod(m, caddr_t),
337 ip = mtod(m, struct ip *);
338 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
339 ip->ip_len = ntohs(ip->ip_len) + msiz;
340 } else { /* AF_INET */
341 IF_DROP(&ifp->if_snd);
346 } else if (sc->g_proto == IPPROTO_GRE) {
347 switch (dst->sa_family) {
349 ip = mtod(m, struct ip *);
350 etype = ETHERTYPE_IP;
354 etype = ETHERTYPE_ATALK;
358 IF_DROP(&ifp->if_snd);
360 error = EAFNOSUPPORT;
363 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT);
365 IF_DROP(&ifp->if_snd);
371 if (m == NULL) { /* impossible */
372 IF_DROP(&ifp->if_snd);
377 gh = mtod(m, struct greip *);
378 if (sc->g_proto == IPPROTO_GRE) {
379 /* we don't have any GRE flags for now */
381 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
382 gh->gi_ptype = htons(etype);
385 gh->gi_pr = sc->g_proto;
386 if (sc->g_proto != IPPROTO_MOBILE) {
387 gh->gi_src = sc->g_src;
388 gh->gi_dst = sc->g_dst;
389 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
390 ((struct ip*)gh)->ip_ttl = GRE_TTL;
391 ((struct ip*)gh)->ip_tos = ip->ip_tos;
392 ((struct ip*)gh)->ip_id = ip->ip_id;
393 gh->gi_len = m->m_pkthdr.len;
397 ifp->if_obytes += m->m_pkthdr.len;
399 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
408 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
413 ifnet_serialize_tx(ifp);
414 error = gre_output_serialized(ifp, m, dst, rt);
415 ifnet_deserialize_tx(ifp);
421 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
423 struct ifreq *ifr = (struct ifreq *)data;
424 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
425 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
426 struct gre_softc *sc = ifp->if_softc;
427 struct sockaddr_in si;
428 struct sockaddr *sa = NULL;
430 struct sockaddr_in sp, sm, dp, dm;
437 ifp->if_flags |= IFF_UP;
442 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
444 if ((ifr->ifr_flags & IFF_LINK0) != 0)
445 sc->g_proto = IPPROTO_GRE;
447 sc->g_proto = IPPROTO_MOBILE;
450 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
452 if (ifr->ifr_mtu < 576) {
456 ifp->if_mtu = ifr->ifr_mtu;
459 ifr->ifr_mtu = sc->sc_if.if_mtu;
463 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
466 error = EAFNOSUPPORT;
469 switch (ifr->ifr_addr.sa_family) {
475 error = EAFNOSUPPORT;
480 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
482 sc->g_proto = ifr->ifr_flags;
483 switch (sc->g_proto) {
485 ifp->if_flags |= IFF_LINK0;
488 ifp->if_flags &= ~IFF_LINK0;
491 error = EPROTONOSUPPORT;
496 ifr->ifr_flags = sc->g_proto;
500 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
503 * set tunnel endpoints, compute a less specific route
504 * to the remote end and mark if as up
507 if (cmd == GRESADDRS)
508 sc->g_src = (satosin(sa))->sin_addr;
509 if (cmd == GRESADDRD)
510 sc->g_dst = (satosin(sa))->sin_addr;
513 if (sc->encap != NULL) {
514 encap_detach(sc->encap);
518 if ((sc->g_src.s_addr != INADDR_ANY) &&
519 (sc->g_dst.s_addr != INADDR_ANY)) {
520 bzero(&sp, sizeof(sp));
521 bzero(&sm, sizeof(sm));
522 bzero(&dp, sizeof(dp));
523 bzero(&dm, sizeof(dm));
524 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
525 sizeof(struct sockaddr_in);
526 sp.sin_family = sm.sin_family = dp.sin_family =
527 dm.sin_family = AF_INET;
528 sp.sin_addr = sc->g_src;
529 dp.sin_addr = sc->g_dst;
530 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
533 sc->encap = encap_attach(AF_INET, sc->g_proto,
534 sintosa(&sp), sintosa(&sm), sintosa(&dp),
535 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
536 &in_gre_protosw : &in_mobile_protosw, sc);
537 if (sc->encap == NULL)
538 kprintf("%s: unable to attach encap\n",
539 if_name(&sc->sc_if));
541 if (sc->route.ro_rt != 0) /* free old route */
542 RTFREE(sc->route.ro_rt);
543 if (gre_compute_route(sc) == 0)
544 ifp->if_flags |= IFF_RUNNING;
546 ifp->if_flags &= ~IFF_RUNNING;
550 memset(&si, 0, sizeof(si));
551 si.sin_family = AF_INET;
552 si.sin_len = sizeof(struct sockaddr_in);
553 si.sin_addr.s_addr = sc->g_src.s_addr;
558 memset(&si, 0, sizeof(si));
559 si.sin_family = AF_INET;
560 si.sin_len = sizeof(struct sockaddr_in);
561 si.sin_addr.s_addr = sc->g_dst.s_addr;
566 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
568 if (aifr->ifra_addr.sin_family != AF_INET ||
569 aifr->ifra_dstaddr.sin_family != AF_INET) {
570 error = EAFNOSUPPORT;
573 if (aifr->ifra_addr.sin_len != sizeof(si) ||
574 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
578 sc->g_src = aifr->ifra_addr.sin_addr;
579 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
581 case SIOCSLIFPHYADDR:
582 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
584 if (lifr->addr.ss_family != AF_INET ||
585 lifr->dstaddr.ss_family != AF_INET) {
586 error = EAFNOSUPPORT;
589 if (lifr->addr.ss_len != sizeof(si) ||
590 lifr->dstaddr.ss_len != sizeof(si)) {
594 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
596 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
599 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
601 sc->g_src.s_addr = INADDR_ANY;
602 sc->g_dst.s_addr = INADDR_ANY;
604 case SIOCGLIFPHYADDR:
605 if (sc->g_src.s_addr == INADDR_ANY ||
606 sc->g_dst.s_addr == INADDR_ANY) {
607 error = EADDRNOTAVAIL;
610 memset(&si, 0, sizeof(si));
611 si.sin_family = AF_INET;
612 si.sin_len = sizeof(struct sockaddr_in);
613 si.sin_addr.s_addr = sc->g_src.s_addr;
614 memcpy(&lifr->addr, &si, sizeof(si));
615 si.sin_addr.s_addr = sc->g_dst.s_addr;
616 memcpy(&lifr->dstaddr, &si, sizeof(si));
618 case SIOCGIFPSRCADDR:
619 if (sc->g_src.s_addr == INADDR_ANY) {
620 error = EADDRNOTAVAIL;
623 memset(&si, 0, sizeof(si));
624 si.sin_family = AF_INET;
625 si.sin_len = sizeof(struct sockaddr_in);
626 si.sin_addr.s_addr = sc->g_src.s_addr;
627 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
629 case SIOCGIFPDSTADDR:
630 if (sc->g_dst.s_addr == INADDR_ANY) {
631 error = EADDRNOTAVAIL;
634 memset(&si, 0, sizeof(si));
635 si.sin_family = AF_INET;
636 si.sin_len = sizeof(struct sockaddr_in);
637 si.sin_addr.s_addr = sc->g_dst.s_addr;
638 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
650 * computes a route to our destination that is not the one
651 * which would be taken by ip_output(), as this one will loop back to
652 * us. If the interface is p2p as a--->b, then a routing entry exists
653 * If we now send a packet to b (e.g. ping b), this will come down here
654 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
656 * Goal here is to compute a route to b that is less specific than
657 * a-->b. We know that this one exists as in normal operation we have
658 * at least a default route which matches.
661 gre_compute_route(struct gre_softc *sc)
668 memset(ro, 0, sizeof(struct route));
669 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
670 ro->ro_dst.sa_family = AF_INET;
671 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
674 * toggle last bit, so our interface is not found, but a less
675 * specific route. I'd rather like to specify a shorter mask,
676 * but this is not possible. Should work though. XXX
677 * there is a simpler way ...
679 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
680 a = ntohl(sc->g_dst.s_addr);
685 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
690 kprintf("%s: searching a route to %s", if_name(&sc->sc_if),
691 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
697 * check if this returned a route at all and this route is no
698 * recursion to ourself
700 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
702 if (ro->ro_rt == NULL)
703 kprintf(" - no route found!\n");
705 kprintf(" - route loops back to ourself!\n");
707 return EADDRNOTAVAIL;
711 * now change it back - else ip_output will just drop
712 * the route and search one to this interface ...
714 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
715 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
718 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
719 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
727 * do a checksum of a buffer - much like in_cksum, which operates on
731 gre_in_cksum(u_short *p, u_int len)
734 int nwords = len >> 1;
736 while (nwords-- != 0)
744 u.c[0] = *(u_char *)p;
749 /* end-around-carry */
750 sum = (sum >> 16) + (sum & 0xffff);
756 gremodevent(module_t mod, int type, void *data)
764 if_clone_detach(&gre_cloner);
766 while (!LIST_EMPTY(&gre_softc_list))
767 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
774 static moduledata_t gre_mod = {
780 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
781 MODULE_VERSION(if_gre, 1);