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
51 #include <sys/param.h>
52 #include <sys/kernel.h>
54 #include <sys/malloc.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 #include <sys/thread2.h>
65 #include <net/ethernet.h>
67 #include <net/if_types.h>
68 #include <net/ifq_var.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 ifq_set_maxlen(&sc->sc_if.if_snd, 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;
240 struct mobile_h mob_h;
243 * gre may cause infinite recursion calls when misconfigured.
244 * We'll prevent this by introducing upper limit.
246 if (++(sc->called) > max_gre_nesting) {
247 kprintf("%s: gre_output: recursively called too many "
248 "times(%d)\n", if_name(&sc->sc_if), sc->called);
250 error = EIO; /* is there better errno? */
254 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
255 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));
274 m->m_flags &= ~(M_BCAST|M_MCAST);
276 if (sc->g_proto == IPPROTO_MOBILE) {
277 if (dst->sa_family == AF_INET) {
281 ip = mtod(m, struct ip *);
284 * RFC2004 specifies that fragmented datagrams shouldn't
287 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
289 error = EINVAL; /* is there better errno? */
292 memset(&mob_h, 0, MOB_H_SIZ_L);
293 mob_h.proto = (ip->ip_p) << 8;
294 mob_h.odst = ip->ip_dst.s_addr;
295 ip->ip_dst.s_addr = sc->g_dst.s_addr;
298 * If the packet comes from our host, we only change
299 * the destination address in the IP header.
300 * Else we also need to save and change the source
302 if (in_hosteq(ip->ip_src, sc->g_src)) {
305 mob_h.proto |= MOB_H_SBIT;
306 mob_h.osrc = ip->ip_src.s_addr;
307 ip->ip_src.s_addr = sc->g_src.s_addr;
310 mob_h.proto = htons(mob_h.proto);
311 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
313 if ((m->m_data - msiz) < m->m_pktdat) {
315 MGETHDR(m0, MB_DONTWAIT, MT_HEADER);
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 */
345 } else if (sc->g_proto == IPPROTO_GRE) {
346 switch (dst->sa_family) {
348 ip = mtod(m, struct ip *);
349 etype = ETHERTYPE_IP;
353 error = EAFNOSUPPORT;
356 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT);
363 if (m == NULL) { /* impossible */
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_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
404 ifnet_serialize_tx(ifp);
405 error = gre_output_serialized(ifp, m, dst, rt);
406 ifnet_deserialize_tx(ifp);
412 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
414 struct ifreq *ifr = (struct ifreq *)data;
415 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
416 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
417 struct gre_softc *sc = ifp->if_softc;
418 struct sockaddr_in si;
419 struct sockaddr *sa = NULL;
421 struct sockaddr_in sp, sm, dp, dm;
428 ifp->if_flags |= IFF_UP;
433 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
435 if ((ifr->ifr_flags & IFF_LINK0) != 0)
436 sc->g_proto = IPPROTO_GRE;
438 sc->g_proto = IPPROTO_MOBILE;
441 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
443 if (ifr->ifr_mtu < 576) {
447 ifp->if_mtu = ifr->ifr_mtu;
450 ifr->ifr_mtu = sc->sc_if.if_mtu;
454 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
457 error = EAFNOSUPPORT;
460 switch (ifr->ifr_addr.sa_family) {
466 error = EAFNOSUPPORT;
471 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
473 sc->g_proto = ifr->ifr_flags;
474 switch (sc->g_proto) {
476 ifp->if_flags |= IFF_LINK0;
479 ifp->if_flags &= ~IFF_LINK0;
482 error = EPROTONOSUPPORT;
487 ifr->ifr_flags = sc->g_proto;
491 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
494 * set tunnel endpoints, compute a less specific route
495 * to the remote end and mark if as up
498 if (cmd == GRESADDRS)
499 sc->g_src = (satosin(sa))->sin_addr;
500 if (cmd == GRESADDRD)
501 sc->g_dst = (satosin(sa))->sin_addr;
504 if (sc->encap != NULL) {
505 encap_detach(sc->encap);
509 if ((sc->g_src.s_addr != INADDR_ANY) &&
510 (sc->g_dst.s_addr != INADDR_ANY)) {
511 bzero(&sp, sizeof(sp));
512 bzero(&sm, sizeof(sm));
513 bzero(&dp, sizeof(dp));
514 bzero(&dm, sizeof(dm));
515 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
516 sizeof(struct sockaddr_in);
517 sp.sin_family = sm.sin_family = dp.sin_family =
518 dm.sin_family = AF_INET;
519 sp.sin_addr = sc->g_src;
520 dp.sin_addr = sc->g_dst;
521 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
524 sc->encap = encap_attach(AF_INET, sc->g_proto,
525 sintosa(&sp), sintosa(&sm), sintosa(&dp),
526 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
527 &in_gre_protosw : &in_mobile_protosw, sc);
528 if (sc->encap == NULL)
529 kprintf("%s: unable to attach encap\n",
530 if_name(&sc->sc_if));
532 if (sc->route.ro_rt != 0) /* free old route */
533 RTFREE(sc->route.ro_rt);
534 if (gre_compute_route(sc) == 0)
535 ifp->if_flags |= IFF_RUNNING;
537 ifp->if_flags &= ~IFF_RUNNING;
541 memset(&si, 0, sizeof(si));
542 si.sin_family = AF_INET;
543 si.sin_len = sizeof(struct sockaddr_in);
544 si.sin_addr.s_addr = sc->g_src.s_addr;
549 memset(&si, 0, sizeof(si));
550 si.sin_family = AF_INET;
551 si.sin_len = sizeof(struct sockaddr_in);
552 si.sin_addr.s_addr = sc->g_dst.s_addr;
557 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
559 if (aifr->ifra_addr.sin_family != AF_INET ||
560 aifr->ifra_dstaddr.sin_family != AF_INET) {
561 error = EAFNOSUPPORT;
564 if (aifr->ifra_addr.sin_len != sizeof(si) ||
565 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
569 sc->g_src = aifr->ifra_addr.sin_addr;
570 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
572 case SIOCSLIFPHYADDR:
573 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
575 if (lifr->addr.ss_family != AF_INET ||
576 lifr->dstaddr.ss_family != AF_INET) {
577 error = EAFNOSUPPORT;
580 if (lifr->addr.ss_len != sizeof(si) ||
581 lifr->dstaddr.ss_len != sizeof(si)) {
585 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
587 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
590 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
592 sc->g_src.s_addr = INADDR_ANY;
593 sc->g_dst.s_addr = INADDR_ANY;
595 case SIOCGLIFPHYADDR:
596 if (sc->g_src.s_addr == INADDR_ANY ||
597 sc->g_dst.s_addr == INADDR_ANY) {
598 error = EADDRNOTAVAIL;
601 memset(&si, 0, sizeof(si));
602 si.sin_family = AF_INET;
603 si.sin_len = sizeof(struct sockaddr_in);
604 si.sin_addr.s_addr = sc->g_src.s_addr;
605 memcpy(&lifr->addr, &si, sizeof(si));
606 si.sin_addr.s_addr = sc->g_dst.s_addr;
607 memcpy(&lifr->dstaddr, &si, sizeof(si));
609 case SIOCGIFPSRCADDR:
610 if (sc->g_src.s_addr == INADDR_ANY) {
611 error = EADDRNOTAVAIL;
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));
620 case SIOCGIFPDSTADDR:
621 if (sc->g_dst.s_addr == INADDR_ANY) {
622 error = EADDRNOTAVAIL;
625 memset(&si, 0, sizeof(si));
626 si.sin_family = AF_INET;
627 si.sin_len = sizeof(struct sockaddr_in);
628 si.sin_addr.s_addr = sc->g_dst.s_addr;
629 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
641 * computes a route to our destination that is not the one
642 * which would be taken by ip_output(), as this one will loop back to
643 * us. If the interface is p2p as a--->b, then a routing entry exists
644 * If we now send a packet to b (e.g. ping b), this will come down here
645 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
647 * Goal here is to compute a route to b that is less specific than
648 * a-->b. We know that this one exists as in normal operation we have
649 * at least a default route which matches.
652 gre_compute_route(struct gre_softc *sc)
659 memset(ro, 0, sizeof(struct route));
660 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
661 ro->ro_dst.sa_family = AF_INET;
662 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
665 * toggle last bit, so our interface is not found, but a less
666 * specific route. I'd rather like to specify a shorter mask,
667 * but this is not possible. Should work though. XXX
668 * there is a simpler way ...
670 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
671 a = ntohl(sc->g_dst.s_addr);
676 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
681 kprintf("%s: searching a route to %s", if_name(&sc->sc_if),
682 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
688 * check if this returned a route at all and this route is no
689 * recursion to ourself
691 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
693 if (ro->ro_rt == NULL)
694 kprintf(" - no route found!\n");
696 kprintf(" - route loops back to ourself!\n");
698 return EADDRNOTAVAIL;
702 * now change it back - else ip_output will just drop
703 * the route and search one to this interface ...
705 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
706 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
709 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
710 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
718 * do a checksum of a buffer - much like in_cksum, which operates on
722 gre_in_cksum(u_short *p, u_int len)
725 int nwords = len >> 1;
727 while (nwords-- != 0)
735 u.c[0] = *(u_char *)p;
740 /* end-around-carry */
741 sum = (sum >> 16) + (sum & 0xffff);
747 gremodevent(module_t mod, int type, void *data)
755 if_clone_detach(&gre_cloner);
757 while (!LIST_EMPTY(&gre_softc_list))
758 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
765 static moduledata_t gre_mod = {
771 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
772 MODULE_VERSION(if_gre, 1);