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 1.13 2005/06/03 18:20:37 swildner 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(ifc, unit)
162 struct if_clone *ifc;
165 struct gre_softc *sc;
167 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
168 memset(sc, 0, sizeof(struct gre_softc));
170 sc->sc_if.if_softc = sc;
171 if_initname(&(sc->sc_if), GRENAME, unit);
172 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
173 sc->sc_if.if_type = IFT_OTHER;
174 sc->sc_if.if_addrlen = 0;
175 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
176 sc->sc_if.if_mtu = GREMTU;
177 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
178 sc->sc_if.if_output = gre_output;
179 sc->sc_if.if_ioctl = gre_ioctl;
180 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
181 sc->g_proto = IPPROTO_GRE;
182 sc->sc_if.if_flags |= IFF_LINK0;
185 if_attach(&sc->sc_if);
186 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
187 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
192 gre_clone_destroy(ifp)
195 struct gre_softc *sc = ifp->if_softc;
198 if (sc->encap != NULL)
199 encap_detach(sc->encap);
201 LIST_REMOVE(sc, sc_list);
209 * The output routine. Takes a packet and encapsulates it in the protocol
210 * given by sc->g_proto. See also RFC 1701 and RFC 2004
213 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
217 struct gre_softc *sc = ifp->if_softc;
222 struct mobile_h mob_h;
225 * gre may cause infinite recursion calls when misconfigured.
226 * We'll prevent this by introducing upper limit.
228 if (++(sc->called) > max_gre_nesting) {
229 printf("%s: gre_output: recursively called too many "
230 "times(%d)\n", if_name(&sc->sc_if), sc->called);
232 error = EIO; /* is there better errno? */
236 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
237 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
248 uint32_t af = dst->sa_family;
250 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
253 m->m_flags &= ~(M_BCAST|M_MCAST);
255 if (sc->g_proto == IPPROTO_MOBILE) {
256 if (dst->sa_family == AF_INET) {
260 ip = mtod(m, struct ip *);
263 * RFC2004 specifies that fragmented diagrams shouldn't
266 if ((ip->ip_off & IP_MF) != 0) {
267 IF_DROP(&ifp->if_snd);
269 error = EINVAL; /* is there better errno? */
272 memset(&mob_h, 0, MOB_H_SIZ_L);
273 mob_h.proto = (ip->ip_p) << 8;
274 mob_h.odst = ip->ip_dst.s_addr;
275 ip->ip_dst.s_addr = sc->g_dst.s_addr;
278 * If the packet comes from our host, we only change
279 * the destination address in the IP header.
280 * Else we also need to save and change the source
282 if (in_hosteq(ip->ip_src, sc->g_src)) {
285 mob_h.proto |= MOB_H_SBIT;
286 mob_h.osrc = ip->ip_src.s_addr;
287 ip->ip_src.s_addr = sc->g_src.s_addr;
290 mob_h.proto = htons(mob_h.proto);
291 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
293 if ((m->m_data - msiz) < m->m_pktdat) {
295 MGETHDR(m0, MB_DONTWAIT, MT_HEADER);
297 IF_DROP(&ifp->if_snd);
303 m->m_data += sizeof(struct ip);
304 m->m_len -= sizeof(struct ip);
305 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
306 m0->m_len = msiz + sizeof(struct ip);
307 m0->m_data += max_linkhdr;
308 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
311 } else { /* we have some space left in the old one */
314 m->m_pkthdr.len += msiz;
315 bcopy(ip, mtod(m, caddr_t),
318 ip = mtod(m, struct ip *);
319 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
320 ip->ip_len = ntohs(ip->ip_len) + msiz;
321 } else { /* AF_INET */
322 IF_DROP(&ifp->if_snd);
327 } else if (sc->g_proto == IPPROTO_GRE) {
328 switch (dst->sa_family) {
330 ip = mtod(m, struct ip *);
331 etype = ETHERTYPE_IP;
335 etype = ETHERTYPE_ATALK;
340 etype = ETHERTYPE_NS;
344 IF_DROP(&ifp->if_snd);
346 error = EAFNOSUPPORT;
349 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT);
351 IF_DROP(&ifp->if_snd);
357 if (m == NULL) { /* impossible */
358 IF_DROP(&ifp->if_snd);
363 gh = mtod(m, struct greip *);
364 if (sc->g_proto == IPPROTO_GRE) {
365 /* we don't have any GRE flags for now */
367 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
368 gh->gi_ptype = htons(etype);
371 gh->gi_pr = sc->g_proto;
372 if (sc->g_proto != IPPROTO_MOBILE) {
373 gh->gi_src = sc->g_src;
374 gh->gi_dst = sc->g_dst;
375 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
376 ((struct ip*)gh)->ip_ttl = GRE_TTL;
377 ((struct ip*)gh)->ip_tos = ip->ip_tos;
378 ((struct ip*)gh)->ip_id = ip->ip_id;
379 gh->gi_len = m->m_pkthdr.len;
383 ifp->if_obytes += m->m_pkthdr.len;
385 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
394 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
396 struct ifreq *ifr = (struct ifreq *)data;
397 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
398 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
399 struct gre_softc *sc = ifp->if_softc;
400 struct sockaddr_in si;
401 struct sockaddr *sa = NULL;
403 struct sockaddr_in sp, sm, dp, dm;
410 ifp->if_flags |= IFF_UP;
415 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
417 if ((ifr->ifr_flags & IFF_LINK0) != 0)
418 sc->g_proto = IPPROTO_GRE;
420 sc->g_proto = IPPROTO_MOBILE;
423 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
425 if (ifr->ifr_mtu < 576) {
429 ifp->if_mtu = ifr->ifr_mtu;
432 ifr->ifr_mtu = sc->sc_if.if_mtu;
436 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
439 error = EAFNOSUPPORT;
442 switch (ifr->ifr_addr.sa_family) {
448 error = EAFNOSUPPORT;
453 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
455 sc->g_proto = ifr->ifr_flags;
456 switch (sc->g_proto) {
458 ifp->if_flags |= IFF_LINK0;
461 ifp->if_flags &= ~IFF_LINK0;
464 error = EPROTONOSUPPORT;
469 ifr->ifr_flags = sc->g_proto;
473 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
476 * set tunnel endpoints, compute a less specific route
477 * to the remote end and mark if as up
480 if (cmd == GRESADDRS)
481 sc->g_src = (satosin(sa))->sin_addr;
482 if (cmd == GRESADDRD)
483 sc->g_dst = (satosin(sa))->sin_addr;
486 if (sc->encap != NULL) {
487 encap_detach(sc->encap);
491 if ((sc->g_src.s_addr != INADDR_ANY) &&
492 (sc->g_dst.s_addr != INADDR_ANY)) {
493 bzero(&sp, sizeof(sp));
494 bzero(&sm, sizeof(sm));
495 bzero(&dp, sizeof(dp));
496 bzero(&dm, sizeof(dm));
497 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
498 sizeof(struct sockaddr_in);
499 sp.sin_family = sm.sin_family = dp.sin_family =
500 dm.sin_family = AF_INET;
501 sp.sin_addr = sc->g_src;
502 dp.sin_addr = sc->g_dst;
503 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
506 sc->encap = encap_attach(AF_INET, sc->g_proto,
507 sintosa(&sp), sintosa(&sm), sintosa(&dp),
508 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
509 &in_gre_protosw : &in_mobile_protosw, sc);
510 if (sc->encap == NULL)
511 printf("%s: unable to attach encap\n",
512 if_name(&sc->sc_if));
514 if (sc->route.ro_rt != 0) /* free old route */
515 RTFREE(sc->route.ro_rt);
516 if (gre_compute_route(sc) == 0)
517 ifp->if_flags |= IFF_RUNNING;
519 ifp->if_flags &= ~IFF_RUNNING;
523 memset(&si, 0, sizeof(si));
524 si.sin_family = AF_INET;
525 si.sin_len = sizeof(struct sockaddr_in);
526 si.sin_addr.s_addr = sc->g_src.s_addr;
531 memset(&si, 0, sizeof(si));
532 si.sin_family = AF_INET;
533 si.sin_len = sizeof(struct sockaddr_in);
534 si.sin_addr.s_addr = sc->g_dst.s_addr;
539 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
541 if (aifr->ifra_addr.sin_family != AF_INET ||
542 aifr->ifra_dstaddr.sin_family != AF_INET) {
543 error = EAFNOSUPPORT;
546 if (aifr->ifra_addr.sin_len != sizeof(si) ||
547 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
551 sc->g_src = aifr->ifra_addr.sin_addr;
552 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
554 case SIOCSLIFPHYADDR:
555 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
557 if (lifr->addr.ss_family != AF_INET ||
558 lifr->dstaddr.ss_family != AF_INET) {
559 error = EAFNOSUPPORT;
562 if (lifr->addr.ss_len != sizeof(si) ||
563 lifr->dstaddr.ss_len != sizeof(si)) {
567 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
569 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
572 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
574 sc->g_src.s_addr = INADDR_ANY;
575 sc->g_dst.s_addr = INADDR_ANY;
577 case SIOCGLIFPHYADDR:
578 if (sc->g_src.s_addr == INADDR_ANY ||
579 sc->g_dst.s_addr == INADDR_ANY) {
580 error = EADDRNOTAVAIL;
583 memset(&si, 0, sizeof(si));
584 si.sin_family = AF_INET;
585 si.sin_len = sizeof(struct sockaddr_in);
586 si.sin_addr.s_addr = sc->g_src.s_addr;
587 memcpy(&lifr->addr, &si, sizeof(si));
588 si.sin_addr.s_addr = sc->g_dst.s_addr;
589 memcpy(&lifr->dstaddr, &si, sizeof(si));
591 case SIOCGIFPSRCADDR:
592 if (sc->g_src.s_addr == INADDR_ANY) {
593 error = EADDRNOTAVAIL;
596 memset(&si, 0, sizeof(si));
597 si.sin_family = AF_INET;
598 si.sin_len = sizeof(struct sockaddr_in);
599 si.sin_addr.s_addr = sc->g_src.s_addr;
600 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
602 case SIOCGIFPDSTADDR:
603 if (sc->g_dst.s_addr == INADDR_ANY) {
604 error = EADDRNOTAVAIL;
607 memset(&si, 0, sizeof(si));
608 si.sin_family = AF_INET;
609 si.sin_len = sizeof(struct sockaddr_in);
610 si.sin_addr.s_addr = sc->g_dst.s_addr;
611 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
623 * computes a route to our destination that is not the one
624 * which would be taken by ip_output(), as this one will loop back to
625 * us. If the interface is p2p as a--->b, then a routing entry exists
626 * If we now send a packet to b (e.g. ping b), this will come down here
627 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
629 * Goal here is to compute a route to b that is less specific than
630 * a-->b. We know that this one exists as in normal operation we have
631 * at least a default route which matches.
634 gre_compute_route(struct gre_softc *sc)
641 memset(ro, 0, sizeof(struct route));
642 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
643 ro->ro_dst.sa_family = AF_INET;
644 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
647 * toggle last bit, so our interface is not found, but a less
648 * specific route. I'd rather like to specify a shorter mask,
649 * but this is not possible. Should work though. XXX
650 * there is a simpler way ...
652 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
653 a = ntohl(sc->g_dst.s_addr);
658 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
663 printf("%s: searching a route to %s", if_name(&sc->sc_if),
664 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
670 * check if this returned a route at all and this route is no
671 * recursion to ourself
673 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
675 if (ro->ro_rt == NULL)
676 printf(" - no route found!\n");
678 printf(" - route loops back to ourself!\n");
680 return EADDRNOTAVAIL;
684 * now change it back - else ip_output will just drop
685 * the route and search one to this interface ...
687 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
688 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
691 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
692 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
700 * do a checksum of a buffer - much like in_cksum, which operates on
704 gre_in_cksum(u_short *p, u_int len)
707 int nwords = len >> 1;
709 while (nwords-- != 0)
717 u.c[0] = *(u_char *)p;
722 /* end-around-carry */
723 sum = (sum >> 16) + (sum & 0xffff);
729 gremodevent(module_t mod, int type, void *data)
737 if_clone_detach(&gre_cloner);
739 while (!LIST_EMPTY(&gre_softc_list))
740 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
747 static moduledata_t gre_mod = {
753 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
754 MODULE_VERSION(if_gre, 1);