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"
53 #include <sys/param.h>
54 #include <sys/kernel.h>
55 #include <sys/malloc.h>
58 #include <sys/protosw.h>
59 #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>
86 #include <net/if_gre.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
96 #define GRE_MAXUNIT 0x7fff
98 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
99 static struct rman greunits[1];
101 struct gre_softc_head gre_softc_list;
103 static int gre_clone_create(struct if_clone *, int *);
104 static void gre_clone_destroy(struct ifnet *);
105 static int gre_ioctl(struct ifnet *, u_long, caddr_t);
106 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
109 static struct if_clone gre_cloner =
110 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy);
112 static int gre_compute_route(struct gre_softc *sc);
114 static void greattach(void);
117 extern struct domain inetdomain;
118 static const struct protosw in_gre_protosw =
119 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR,
120 gre_input, rip_output, rip_ctlinput, rip_ctloutput,
125 static const struct protosw in_mobile_protosw =
126 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR,
127 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput,
134 SYSCTL_DECL(_net_link);
135 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0,
136 "Generic Routing Encapsulation");
139 * This macro controls the default upper limitation on nesting of gre tunnels.
140 * Since, setting a large value to this macro with a careless configuration
141 * may introduce system crash, we don't allow any nestings by default.
142 * If you need to configure nested gre tunnels, you can define this macro
143 * in your kernel configuration file. However, if you do so, please be
144 * careful to configure the tunnels so that it won't make a loop.
146 #define MAX_GRE_NEST 1
148 static int max_gre_nesting = MAX_GRE_NEST;
149 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
150 &max_gre_nesting, 0, "Max nested tunnels");
157 LIST_INIT(&gre_softc_list);
158 if_clone_attach(&gre_cloner);
162 gre_clone_create(ifc, unit)
163 struct if_clone *ifc;
167 struct gre_softc *sc;
169 if (*unit > GRE_MAXUNIT)
173 r = rman_reserve_resource(greunits, 0, GRE_MAXUNIT, 1,
174 RF_ALLOCATED | RF_ACTIVE, NULL);
177 *unit = rman_get_start(r);
179 r = rman_reserve_resource(greunits, *unit, *unit, 1,
180 RF_ALLOCATED | RF_ACTIVE, NULL);
185 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
186 memset(sc, 0, sizeof(struct gre_softc));
188 sc->sc_if.if_name = GRENAME;
189 sc->sc_if.if_softc = sc;
190 sc->sc_if.if_unit = *unit;
191 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
192 sc->sc_if.if_type = IFT_OTHER;
193 sc->sc_if.if_addrlen = 0;
194 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
195 sc->sc_if.if_mtu = GREMTU;
196 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
197 sc->sc_if.if_output = gre_output;
198 sc->sc_if.if_ioctl = gre_ioctl;
199 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
200 sc->g_proto = IPPROTO_GRE;
201 sc->sc_if.if_flags |= IFF_LINK0;
205 if_attach(&sc->sc_if);
206 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
207 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
212 gre_clone_destroy(ifp)
216 struct gre_softc *sc = ifp->if_softc;
219 if (sc->encap != NULL)
220 encap_detach(sc->encap);
222 LIST_REMOVE(sc, sc_list);
226 err = rman_release_resource(sc->r_unit);
227 KASSERT(err == 0, ("Unexpected error freeing resource"));
233 * The output routine. Takes a packet and encapsulates it in the protocol
234 * given by sc->g_proto. See also RFC 1701 and RFC 2004
237 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
241 struct gre_softc *sc = ifp->if_softc;
246 struct mobile_h mob_h;
249 * gre may cause infinite recursion calls when misconfigured.
250 * We'll prevent this by introducing upper limit.
252 if (++(sc->called) > max_gre_nesting) {
253 printf("%s: gre_output: recursively called too many "
254 "times(%d)\n", if_name(&sc->sc_if), sc->called);
256 error = EIO; /* is there better errno? */
260 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
261 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
272 /* see comment of other if_foo.c files */
274 u_int32_t af = dst->sa_family;
278 m0.m_data = (char *)⁡
283 m->m_flags &= ~(M_BCAST|M_MCAST);
285 if (sc->g_proto == IPPROTO_MOBILE) {
286 if (dst->sa_family == AF_INET) {
290 ip = mtod(m, struct ip *);
293 * RFC2004 specifies that fragmented diagrams shouldn't
296 if ((ip->ip_off & IP_MF) != 0) {
297 IF_DROP(&ifp->if_snd);
299 error = EINVAL; /* is there better errno? */
302 memset(&mob_h, 0, MOB_H_SIZ_L);
303 mob_h.proto = (ip->ip_p) << 8;
304 mob_h.odst = ip->ip_dst.s_addr;
305 ip->ip_dst.s_addr = sc->g_dst.s_addr;
308 * If the packet comes from our host, we only change
309 * the destination address in the IP header.
310 * Else we also need to save and change the source
312 if (in_hosteq(ip->ip_src, sc->g_src)) {
315 mob_h.proto |= MOB_H_SBIT;
316 mob_h.osrc = ip->ip_src.s_addr;
317 ip->ip_src.s_addr = sc->g_src.s_addr;
320 mob_h.proto = htons(mob_h.proto);
321 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
323 if ((m->m_data - msiz) < m->m_pktdat) {
325 MGETHDR(m0, M_DONTWAIT, MT_HEADER);
327 IF_DROP(&ifp->if_snd);
333 m->m_data += sizeof(struct ip);
334 m->m_len -= sizeof(struct ip);
335 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
336 m0->m_len = msiz + sizeof(struct ip);
337 m0->m_data += max_linkhdr;
338 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
341 } else { /* we have some space left in the old one */
344 m->m_pkthdr.len += msiz;
345 bcopy(ip, mtod(m, caddr_t),
348 ip = mtod(m, struct ip *);
349 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
350 ip->ip_len = ntohs(ip->ip_len) + msiz;
351 } else { /* AF_INET */
352 IF_DROP(&ifp->if_snd);
357 } else if (sc->g_proto == IPPROTO_GRE) {
358 switch (dst->sa_family) {
360 ip = mtod(m, struct ip *);
361 etype = ETHERTYPE_IP;
365 etype = ETHERTYPE_ATALK;
370 etype = ETHERTYPE_NS;
374 IF_DROP(&ifp->if_snd);
376 error = EAFNOSUPPORT;
379 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT);
381 IF_DROP(&ifp->if_snd);
387 if (m == NULL) { /* impossible */
388 IF_DROP(&ifp->if_snd);
393 gh = mtod(m, struct greip *);
394 if (sc->g_proto == IPPROTO_GRE) {
395 /* we don't have any GRE flags for now */
397 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
398 gh->gi_ptype = htons(etype);
401 gh->gi_pr = sc->g_proto;
402 if (sc->g_proto != IPPROTO_MOBILE) {
403 gh->gi_src = sc->g_src;
404 gh->gi_dst = sc->g_dst;
405 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
406 ((struct ip*)gh)->ip_ttl = GRE_TTL;
407 ((struct ip*)gh)->ip_tos = ip->ip_tos;
408 ((struct ip*)gh)->ip_id = ip->ip_id;
409 gh->gi_len = m->m_pkthdr.len;
413 ifp->if_obytes += m->m_pkthdr.len;
415 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
424 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
426 struct ifreq *ifr = (struct ifreq *)data;
427 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
428 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
429 struct gre_softc *sc = ifp->if_softc;
431 struct sockaddr_in si;
432 struct sockaddr *sa = NULL;
434 struct sockaddr_in sp, sm, dp, dm;
441 ifp->if_flags |= IFF_UP;
446 if ((error = suser(curproc)) != 0)
448 if ((ifr->ifr_flags & IFF_LINK0) != 0)
449 sc->g_proto = IPPROTO_GRE;
451 sc->g_proto = IPPROTO_MOBILE;
454 if ((error = suser(curproc)) != 0)
456 if (ifr->ifr_mtu < 576) {
460 ifp->if_mtu = ifr->ifr_mtu;
463 ifr->ifr_mtu = sc->sc_if.if_mtu;
467 if ((error = suser(curproc)) != 0)
470 error = EAFNOSUPPORT;
473 switch (ifr->ifr_addr.sa_family) {
479 error = EAFNOSUPPORT;
484 if ((error = suser(curproc)) != 0)
486 sc->g_proto = ifr->ifr_flags;
487 switch (sc->g_proto) {
489 ifp->if_flags |= IFF_LINK0;
492 ifp->if_flags &= ~IFF_LINK0;
495 error = EPROTONOSUPPORT;
500 ifr->ifr_flags = sc->g_proto;
504 if ((error = suser(curproc)) != 0)
507 * set tunnel endpoints, compute a less specific route
508 * to the remote end and mark if as up
511 if (cmd == GRESADDRS)
512 sc->g_src = (satosin(sa))->sin_addr;
513 if (cmd == GRESADDRD)
514 sc->g_dst = (satosin(sa))->sin_addr;
517 if (sc->encap != NULL) {
518 encap_detach(sc->encap);
522 if ((sc->g_src.s_addr != INADDR_ANY) &&
523 (sc->g_dst.s_addr != INADDR_ANY)) {
524 bzero(&sp, sizeof(sp));
525 bzero(&sm, sizeof(sm));
526 bzero(&dp, sizeof(dp));
527 bzero(&dm, sizeof(dm));
528 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
529 sizeof(struct sockaddr_in);
530 sp.sin_family = sm.sin_family = dp.sin_family =
531 dm.sin_family = AF_INET;
532 sp.sin_addr = sc->g_src;
533 dp.sin_addr = sc->g_dst;
534 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
537 sc->encap = encap_attach(AF_INET, sc->g_proto,
538 sintosa(&sp), sintosa(&sm), sintosa(&dp),
539 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
540 &in_gre_protosw : &in_mobile_protosw, sc);
541 if (sc->encap == NULL)
542 printf("%s: unable to attach encap\n",
543 if_name(&sc->sc_if));
545 if (sc->route.ro_rt != 0) /* free old route */
546 RTFREE(sc->route.ro_rt);
547 if (gre_compute_route(sc) == 0)
548 ifp->if_flags |= IFF_RUNNING;
550 ifp->if_flags &= ~IFF_RUNNING;
554 memset(&si, 0, sizeof(si));
555 si.sin_family = AF_INET;
556 si.sin_len = sizeof(struct sockaddr_in);
557 si.sin_addr.s_addr = sc->g_src.s_addr;
562 memset(&si, 0, sizeof(si));
563 si.sin_family = AF_INET;
564 si.sin_len = sizeof(struct sockaddr_in);
565 si.sin_addr.s_addr = sc->g_dst.s_addr;
570 if ((error = suser(curproc)) != 0)
572 if (aifr->ifra_addr.sin_family != AF_INET ||
573 aifr->ifra_dstaddr.sin_family != AF_INET) {
574 error = EAFNOSUPPORT;
577 if (aifr->ifra_addr.sin_len != sizeof(si) ||
578 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
582 sc->g_src = aifr->ifra_addr.sin_addr;
583 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
585 case SIOCSLIFPHYADDR:
586 if ((error = suser(curproc)) != 0)
588 if (lifr->addr.ss_family != AF_INET ||
589 lifr->dstaddr.ss_family != AF_INET) {
590 error = EAFNOSUPPORT;
593 if (lifr->addr.ss_len != sizeof(si) ||
594 lifr->dstaddr.ss_len != sizeof(si)) {
598 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
600 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
603 if ((error = suser(curproc)) != 0)
605 sc->g_src.s_addr = INADDR_ANY;
606 sc->g_dst.s_addr = INADDR_ANY;
608 case SIOCGLIFPHYADDR:
609 if (sc->g_src.s_addr == INADDR_ANY ||
610 sc->g_dst.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 memcpy(&lifr->addr, &si, sizeof(si));
619 si.sin_addr.s_addr = sc->g_dst.s_addr;
620 memcpy(&lifr->dstaddr, &si, sizeof(si));
622 case SIOCGIFPSRCADDR:
623 if (sc->g_src.s_addr == INADDR_ANY) {
624 error = EADDRNOTAVAIL;
627 memset(&si, 0, sizeof(si));
628 si.sin_family = AF_INET;
629 si.sin_len = sizeof(struct sockaddr_in);
630 si.sin_addr.s_addr = sc->g_src.s_addr;
631 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
633 case SIOCGIFPDSTADDR:
634 if (sc->g_dst.s_addr == INADDR_ANY) {
635 error = EADDRNOTAVAIL;
638 memset(&si, 0, sizeof(si));
639 si.sin_family = AF_INET;
640 si.sin_len = sizeof(struct sockaddr_in);
641 si.sin_addr.s_addr = sc->g_dst.s_addr;
642 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
654 * computes a route to our destination that is not the one
655 * which would be taken by ip_output(), as this one will loop back to
656 * us. If the interface is p2p as a--->b, then a routing entry exists
657 * If we now send a packet to b (e.g. ping b), this will come down here
658 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
660 * Goal here is to compute a route to b that is less specific than
661 * a-->b. We know that this one exists as in normal operation we have
662 * at least a default route which matches.
665 gre_compute_route(struct gre_softc *sc)
672 memset(ro, 0, sizeof(struct route));
673 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
674 ro->ro_dst.sa_family = AF_INET;
675 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
678 * toggle last bit, so our interface is not found, but a less
679 * specific route. I'd rather like to specify a shorter mask,
680 * but this is not possible. Should work though. XXX
681 * there is a simpler way ...
683 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
684 a = ntohl(sc->g_dst.s_addr);
689 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
694 printf("%s: searching a route to %s", if_name(&sc->sc_if),
695 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
701 * check if this returned a route at all and this route is no
702 * recursion to ourself
704 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
706 if (ro->ro_rt == NULL)
707 printf(" - no route found!\n");
709 printf(" - route loops back to ourself!\n");
711 return EADDRNOTAVAIL;
715 * now change it back - else ip_output will just drop
716 * the route and search one to this interface ...
718 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
719 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
722 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
723 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
731 * do a checksum of a buffer - much like in_cksum, which operates on
735 gre_in_cksum(u_short *p, u_int len)
738 int nwords = len >> 1;
740 while (nwords-- != 0)
748 u.c[0] = *(u_char *)p;
753 /* end-around-carry */
754 sum = (sum >> 16) + (sum & 0xffff);
760 gremodevent(module_t mod, int type, void *data)
766 greunits->rm_type = RMAN_ARRAY;
767 greunits->rm_descr = "configurable if_gre units";
768 err = rman_init(greunits);
771 err = rman_manage_region(greunits, 0, GRE_MAXUNIT);
773 printf("%s: greunits: rman_manage_region: Failed %d\n",
781 if_clone_detach(&gre_cloner);
783 while (!LIST_EMPTY(&gre_softc_list))
784 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
786 err = rman_fini(greunits);
795 static moduledata_t gre_mod = {
801 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
802 MODULE_VERSION(if_gre, 1);