1 /* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun 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 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 * must display the following acknowledgement:
23 * This product includes software developed by the NetBSD
24 * Foundation, Inc. and its contributors.
25 * 4. Neither the name of The NetBSD Foundation nor the names of its
26 * contributors may be used to endorse or promote products derived
27 * from this software without specific prior written permission.
29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
39 * POSSIBILITY OF SUCH DAMAGE.
43 * Encapsulate L3 protocols into IP
44 * See RFC 2784 (successor of RFC 1701 and 1702) for more details.
45 * If_gre is compatible with Cisco GRE tunnels, so you can
46 * have a NetBSD box as the other end of a tunnel interface of a Cisco
47 * router. See gre(4) for more details.
48 * Also supported: IP in IP encaps (proto 55) as of RFC 2004
51 #include "opt_atalk.h"
53 #include "opt_inet6.h"
55 #include <sys/param.h>
56 #include <sys/kernel.h>
57 #include <sys/malloc.h>
58 #include <sys/module.h>
60 #include <sys/protosw.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_clone.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/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
98 * gre_mtx protects all global variables in if_gre.c.
99 * XXX: gre_softc data not protected yet.
102 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
104 struct gre_softc_head gre_softc_list;
106 static int gre_clone_create(struct if_clone *, int, caddr_t);
107 static void gre_clone_destroy(struct ifnet *);
108 static int gre_ioctl(struct ifnet *, u_long, caddr_t);
109 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
112 IFC_SIMPLE_DECLARE(gre, 0);
114 static int gre_compute_route(struct gre_softc *sc);
116 static void greattach(void);
119 extern struct domain inetdomain;
120 static const struct protosw in_gre_protosw = {
122 .pr_domain = &inetdomain,
123 .pr_protocol = IPPROTO_GRE,
124 .pr_flags = PR_ATOMIC|PR_ADDR,
125 .pr_input = gre_input,
126 .pr_output = (pr_output_t *)rip_output,
127 .pr_ctlinput = rip_ctlinput,
128 .pr_ctloutput = rip_ctloutput,
129 .pr_usrreqs = &rip_usrreqs
131 static const struct protosw in_mobile_protosw = {
133 .pr_domain = &inetdomain,
134 .pr_protocol = IPPROTO_MOBILE,
135 .pr_flags = PR_ATOMIC|PR_ADDR,
136 .pr_input = gre_mobile_input,
137 .pr_output = (pr_output_t *)rip_output,
138 .pr_ctlinput = rip_ctlinput,
139 .pr_ctloutput = rip_ctloutput,
140 .pr_usrreqs = &rip_usrreqs
144 SYSCTL_DECL(_net_link);
145 SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0,
146 "Generic Routing Encapsulation");
149 * This macro controls the default upper limitation on nesting of gre tunnels.
150 * Since, setting a large value to this macro with a careless configuration
151 * may introduce system crash, we don't allow any nestings by default.
152 * If you need to configure nested gre tunnels, you can define this macro
153 * in your kernel configuration file. However, if you do so, please be
154 * careful to configure the tunnels so that it won't make a loop.
156 #define MAX_GRE_NEST 1
158 static int max_gre_nesting = MAX_GRE_NEST;
159 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
160 &max_gre_nesting, 0, "Max nested tunnels");
167 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF);
168 LIST_INIT(&gre_softc_list);
169 if_clone_attach(&gre_cloner);
173 gre_clone_create(ifc, unit, params)
174 struct if_clone *ifc;
178 struct gre_softc *sc;
180 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO);
182 GRE2IFP(sc) = if_alloc(IFT_TUNNEL);
183 if (GRE2IFP(sc) == NULL) {
188 GRE2IFP(sc)->if_softc = sc;
189 if_initname(GRE2IFP(sc), ifc->ifc_name, unit);
191 GRE2IFP(sc)->if_snd.ifq_maxlen = IFQ_MAXLEN;
192 GRE2IFP(sc)->if_addrlen = 0;
193 GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */
194 GRE2IFP(sc)->if_mtu = GREMTU;
195 GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
196 GRE2IFP(sc)->if_output = gre_output;
197 GRE2IFP(sc)->if_ioctl = gre_ioctl;
198 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
199 sc->g_proto = IPPROTO_GRE;
200 GRE2IFP(sc)->if_flags |= IFF_LINK0;
203 sc->wccp_ver = WCCP_V1;
204 if_attach(GRE2IFP(sc));
205 bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t));
207 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
208 mtx_unlock(&gre_mtx);
213 gre_clone_destroy(ifp)
216 struct gre_softc *sc = ifp->if_softc;
219 LIST_REMOVE(sc, sc_list);
220 mtx_unlock(&gre_mtx);
223 if (sc->encap != NULL)
224 encap_detach(sc->encap);
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;
247 struct mobile_h mob_h;
251 * gre may cause infinite recursion calls when misconfigured.
252 * We'll prevent this by introducing upper limit.
254 if (++(sc->called) > max_gre_nesting) {
255 printf("%s: gre_output: recursively called too many "
256 "times(%d)\n", if_name(GRE2IFP(sc)), sc->called);
258 error = EIO; /* is there better errno? */
262 if (!((ifp->if_flags & IFF_UP) &&
263 (ifp->if_drv_flags & IFF_DRV_RUNNING)) ||
264 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
273 /* BPF writes need to be handled specially. */
274 if (dst->sa_family == AF_UNSPEC) {
275 bcopy(dst->sa_data, &af, sizeof(af));
279 if (bpf_peers_present(ifp->if_bpf)) {
281 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
284 m->m_flags &= ~(M_BCAST|M_MCAST);
286 if (sc->g_proto == IPPROTO_MOBILE) {
287 if (dst->sa_family == AF_INET) {
291 ip = mtod(m, struct ip *);
294 * RFC2004 specifies that fragmented diagrams shouldn't
297 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
298 _IF_DROP(&ifp->if_snd);
300 error = EINVAL; /* is there better errno? */
303 memset(&mob_h, 0, MOB_H_SIZ_L);
304 mob_h.proto = (ip->ip_p) << 8;
305 mob_h.odst = ip->ip_dst.s_addr;
306 ip->ip_dst.s_addr = sc->g_dst.s_addr;
309 * If the packet comes from our host, we only change
310 * the destination address in the IP header.
311 * Else we also need to save and change the source
313 if (in_hosteq(ip->ip_src, sc->g_src)) {
316 mob_h.proto |= MOB_H_SBIT;
317 mob_h.osrc = ip->ip_src.s_addr;
318 ip->ip_src.s_addr = sc->g_src.s_addr;
321 mob_h.proto = htons(mob_h.proto);
322 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
324 if ((m->m_data - msiz) < m->m_pktdat) {
326 MGETHDR(m0, M_DONTWAIT, MT_DATA);
328 _IF_DROP(&ifp->if_snd);
334 m->m_data += sizeof(struct ip);
335 m->m_len -= sizeof(struct ip);
336 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
337 m0->m_len = msiz + sizeof(struct ip);
338 m0->m_data += max_linkhdr;
339 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
342 } else { /* we have some space left in the old one */
345 m->m_pkthdr.len += msiz;
346 bcopy(ip, mtod(m, caddr_t),
349 ip = mtod(m, struct ip *);
350 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
351 ip->ip_len = ntohs(ip->ip_len) + msiz;
352 } else { /* AF_INET */
353 _IF_DROP(&ifp->if_snd);
358 } else if (sc->g_proto == IPPROTO_GRE) {
359 switch (dst->sa_family) {
361 ip = mtod(m, struct ip *);
364 etype = ETHERTYPE_IP;
369 etype = ETHERTYPE_IPV6;
374 etype = ETHERTYPE_ATALK;
378 _IF_DROP(&ifp->if_snd);
380 error = EAFNOSUPPORT;
383 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT);
385 _IF_DROP(&ifp->if_snd);
391 if (m == NULL) { /* mbuf allocation failed */
392 _IF_DROP(&ifp->if_snd);
397 gh = mtod(m, struct greip *);
398 if (sc->g_proto == IPPROTO_GRE) {
399 /* we don't have any GRE flags for now */
400 memset((void *)gh, 0, sizeof(struct greip));
401 gh->gi_ptype = htons(etype);
404 gh->gi_pr = sc->g_proto;
405 if (sc->g_proto != IPPROTO_MOBILE) {
406 gh->gi_src = sc->g_src;
407 gh->gi_dst = sc->g_dst;
408 ((struct ip*)gh)->ip_v = IPPROTO_IPV4;
409 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
410 ((struct ip*)gh)->ip_ttl = GRE_TTL;
411 ((struct ip*)gh)->ip_tos = ip_tos;
412 ((struct ip*)gh)->ip_id = ip_id;
413 gh->gi_len = m->m_pkthdr.len;
417 ifp->if_obytes += m->m_pkthdr.len;
419 * Send it off and with IP_FORWARD flag to prevent it from
420 * overwriting the ip_id again. ip_id is already set to the
421 * ip_id of the encapsulated packet.
423 error = ip_output(m, NULL, &sc->route, IP_FORWARDING,
424 (struct ip_moptions *)NULL, (struct inpcb *)NULL);
433 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
435 struct ifreq *ifr = (struct ifreq *)data;
436 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
437 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
438 struct gre_softc *sc = ifp->if_softc;
440 struct sockaddr_in si;
441 struct sockaddr *sa = NULL;
443 struct sockaddr_in sp, sm, dp, dm;
450 ifp->if_flags |= IFF_UP;
455 if ((error = suser(curthread)) != 0)
457 if ((ifr->ifr_flags & IFF_LINK0) != 0)
458 sc->g_proto = IPPROTO_GRE;
460 sc->g_proto = IPPROTO_MOBILE;
461 if ((ifr->ifr_flags & IFF_LINK2) != 0)
462 sc->wccp_ver = WCCP_V2;
464 sc->wccp_ver = WCCP_V1;
467 if ((error = suser(curthread)) != 0)
469 if (ifr->ifr_mtu < 576) {
473 ifp->if_mtu = ifr->ifr_mtu;
476 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu;
480 if ((error = suser(curthread)) != 0)
483 error = EAFNOSUPPORT;
486 switch (ifr->ifr_addr.sa_family) {
496 error = EAFNOSUPPORT;
501 if ((error = suser(curthread)) != 0)
503 sc->g_proto = ifr->ifr_flags;
504 switch (sc->g_proto) {
506 ifp->if_flags |= IFF_LINK0;
509 ifp->if_flags &= ~IFF_LINK0;
512 error = EPROTONOSUPPORT;
517 ifr->ifr_flags = sc->g_proto;
521 if ((error = suser(curthread)) != 0)
524 * set tunnel endpoints, compute a less specific route
525 * to the remote end and mark if as up
528 if (cmd == GRESADDRS)
529 sc->g_src = (satosin(sa))->sin_addr;
530 if (cmd == GRESADDRD)
531 sc->g_dst = (satosin(sa))->sin_addr;
534 if (sc->encap != NULL) {
535 encap_detach(sc->encap);
539 if ((sc->g_src.s_addr != INADDR_ANY) &&
540 (sc->g_dst.s_addr != INADDR_ANY)) {
541 bzero(&sp, sizeof(sp));
542 bzero(&sm, sizeof(sm));
543 bzero(&dp, sizeof(dp));
544 bzero(&dm, sizeof(dm));
545 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
546 sizeof(struct sockaddr_in);
547 sp.sin_family = sm.sin_family = dp.sin_family =
548 dm.sin_family = AF_INET;
549 sp.sin_addr = sc->g_src;
550 dp.sin_addr = sc->g_dst;
551 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
554 sc->encap = encap_attach(AF_INET, sc->g_proto,
555 sintosa(&sp), sintosa(&sm), sintosa(&dp),
556 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
557 &in_gre_protosw : &in_mobile_protosw, sc);
558 if (sc->encap == NULL)
559 printf("%s: unable to attach encap\n",
560 if_name(GRE2IFP(sc)));
562 if (sc->route.ro_rt != 0) /* free old route */
563 RTFREE(sc->route.ro_rt);
564 if (gre_compute_route(sc) == 0)
565 ifp->if_drv_flags |= IFF_DRV_RUNNING;
567 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
571 memset(&si, 0, sizeof(si));
572 si.sin_family = AF_INET;
573 si.sin_len = sizeof(struct sockaddr_in);
574 si.sin_addr.s_addr = sc->g_src.s_addr;
579 memset(&si, 0, sizeof(si));
580 si.sin_family = AF_INET;
581 si.sin_len = sizeof(struct sockaddr_in);
582 si.sin_addr.s_addr = sc->g_dst.s_addr;
587 if ((error = suser(curthread)) != 0)
589 if (aifr->ifra_addr.sin_family != AF_INET ||
590 aifr->ifra_dstaddr.sin_family != AF_INET) {
591 error = EAFNOSUPPORT;
594 if (aifr->ifra_addr.sin_len != sizeof(si) ||
595 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
599 sc->g_src = aifr->ifra_addr.sin_addr;
600 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
602 case SIOCSLIFPHYADDR:
603 if ((error = suser(curthread)) != 0)
605 if (lifr->addr.ss_family != AF_INET ||
606 lifr->dstaddr.ss_family != AF_INET) {
607 error = EAFNOSUPPORT;
610 if (lifr->addr.ss_len != sizeof(si) ||
611 lifr->dstaddr.ss_len != sizeof(si)) {
615 sc->g_src = (satosin(&lifr->addr))->sin_addr;
617 (satosin(&lifr->dstaddr))->sin_addr;
620 if ((error = suser(curthread)) != 0)
622 sc->g_src.s_addr = INADDR_ANY;
623 sc->g_dst.s_addr = INADDR_ANY;
625 case SIOCGLIFPHYADDR:
626 if (sc->g_src.s_addr == INADDR_ANY ||
627 sc->g_dst.s_addr == INADDR_ANY) {
628 error = EADDRNOTAVAIL;
631 memset(&si, 0, sizeof(si));
632 si.sin_family = AF_INET;
633 si.sin_len = sizeof(struct sockaddr_in);
634 si.sin_addr.s_addr = sc->g_src.s_addr;
635 memcpy(&lifr->addr, &si, sizeof(si));
636 si.sin_addr.s_addr = sc->g_dst.s_addr;
637 memcpy(&lifr->dstaddr, &si, sizeof(si));
639 case SIOCGIFPSRCADDR:
641 case SIOCGIFPSRCADDR_IN6:
643 if (sc->g_src.s_addr == INADDR_ANY) {
644 error = EADDRNOTAVAIL;
647 memset(&si, 0, sizeof(si));
648 si.sin_family = AF_INET;
649 si.sin_len = sizeof(struct sockaddr_in);
650 si.sin_addr.s_addr = sc->g_src.s_addr;
651 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
653 case SIOCGIFPDSTADDR:
655 case SIOCGIFPDSTADDR_IN6:
657 if (sc->g_dst.s_addr == INADDR_ANY) {
658 error = EADDRNOTAVAIL;
661 memset(&si, 0, sizeof(si));
662 si.sin_family = AF_INET;
663 si.sin_len = sizeof(struct sockaddr_in);
664 si.sin_addr.s_addr = sc->g_dst.s_addr;
665 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
677 * computes a route to our destination that is not the one
678 * which would be taken by ip_output(), as this one will loop back to
679 * us. If the interface is p2p as a--->b, then a routing entry exists
680 * If we now send a packet to b (e.g. ping b), this will come down here
681 * gets src=a, dst=b tacked on and would from ip_output() sent back to
683 * Goal here is to compute a route to b that is less specific than
684 * a-->b. We know that this one exists as in normal operation we have
685 * at least a default route which matches.
688 gre_compute_route(struct gre_softc *sc)
695 memset(ro, 0, sizeof(struct route));
696 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
697 ro->ro_dst.sa_family = AF_INET;
698 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
701 * toggle last bit, so our interface is not found, but a less
702 * specific route. I'd rather like to specify a shorter mask,
703 * but this is not possible. Should work though. XXX
704 * there is a simpler way ...
706 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) {
707 a = ntohl(sc->g_dst.s_addr);
712 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
717 printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)),
718 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
724 * check if this returned a route at all and this route is no
725 * recursion to ourself
727 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
729 if (ro->ro_rt == NULL)
730 printf(" - no route found!\n");
732 printf(" - route loops back to ourself!\n");
734 return EADDRNOTAVAIL;
738 * now change it back - else ip_output will just drop
739 * the route and search one to this interface ...
741 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0)
742 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
745 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
746 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
754 * do a checksum of a buffer - much like in_cksum, which operates on
758 gre_in_cksum(u_int16_t *p, u_int len)
761 int nwords = len >> 1;
763 while (nwords-- != 0)
771 u.c[0] = *(u_char *)p;
776 /* end-around-carry */
777 sum = (sum >> 16) + (sum & 0xffff);
783 gremodevent(module_t mod, int type, void *data)
791 if_clone_detach(&gre_cloner);
792 mtx_destroy(&gre_mtx);
800 static moduledata_t gre_mod = {
806 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
807 MODULE_VERSION(if_gre, 1);