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 1.21 2008/05/14 11:59:23 sephe 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>
57 #include <sys/malloc.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>
65 #include <sys/thread2.h>
67 #include <net/ethernet.h>
69 #include <net/if_types.h>
70 #include <net/route.h>
71 #include <net/if_clone.h>
74 #include <netinet/in.h>
75 #include <netinet/in_systm.h>
76 #include <netinet/in_var.h>
77 #include <netinet/ip.h>
78 #include <netinet/ip_gre.h>
79 #include <netinet/ip_var.h>
80 #include <netinet/ip_encap.h>
82 #error "Huh? if_gre without inet?"
87 #include <net/net_osdep.h>
91 * It is not easy to calculate the right value for a GRE MTU.
92 * We leave this task to the admin and use the same default that
99 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
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, struct ucred *);
106 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
109 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre",
110 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT);
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(struct if_clone *ifc, int unit)
164 struct gre_softc *sc;
166 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK);
167 memset(sc, 0, sizeof(struct gre_softc));
169 sc->sc_if.if_softc = sc;
170 if_initname(&(sc->sc_if), GRENAME, unit);
171 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
172 sc->sc_if.if_type = IFT_OTHER;
173 sc->sc_if.if_addrlen = 0;
174 sc->sc_if.if_hdrlen = 24; /* IP + GRE */
175 sc->sc_if.if_mtu = GREMTU;
176 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
177 sc->sc_if.if_output = gre_output;
178 sc->sc_if.if_ioctl = gre_ioctl;
179 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
180 sc->g_proto = IPPROTO_GRE;
181 sc->sc_if.if_flags |= IFF_LINK0;
184 if_attach(&sc->sc_if, NULL);
185 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
186 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
191 gre_clone_destroy(struct ifnet *ifp)
193 struct gre_softc *sc = ifp->if_softc;
196 if (sc->encap != NULL)
197 encap_detach(sc->encap);
199 LIST_REMOVE(sc, sc_list);
207 * The output routine. Takes a packet and encapsulates it in the protocol
208 * given by sc->g_proto. See also RFC 1701 and RFC 2004
211 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
215 struct gre_softc *sc = ifp->if_softc;
220 struct mobile_h mob_h;
223 * gre may cause infinite recursion calls when misconfigured.
224 * We'll prevent this by introducing upper limit.
226 if (++(sc->called) > max_gre_nesting) {
227 kprintf("%s: gre_output: recursively called too many "
228 "times(%d)\n", if_name(&sc->sc_if), sc->called);
230 error = EIO; /* is there better errno? */
234 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
235 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
246 uint32_t af = dst->sa_family;
248 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
251 m->m_flags &= ~(M_BCAST|M_MCAST);
253 if (sc->g_proto == IPPROTO_MOBILE) {
254 if (dst->sa_family == AF_INET) {
258 ip = mtod(m, struct ip *);
261 * RFC2004 specifies that fragmented datagrams shouldn't
264 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
265 IF_DROP(&ifp->if_snd);
267 error = EINVAL; /* is there better errno? */
270 memset(&mob_h, 0, MOB_H_SIZ_L);
271 mob_h.proto = (ip->ip_p) << 8;
272 mob_h.odst = ip->ip_dst.s_addr;
273 ip->ip_dst.s_addr = sc->g_dst.s_addr;
276 * If the packet comes from our host, we only change
277 * the destination address in the IP header.
278 * Else we also need to save and change the source
280 if (in_hosteq(ip->ip_src, sc->g_src)) {
283 mob_h.proto |= MOB_H_SBIT;
284 mob_h.osrc = ip->ip_src.s_addr;
285 ip->ip_src.s_addr = sc->g_src.s_addr;
288 mob_h.proto = htons(mob_h.proto);
289 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz);
291 if ((m->m_data - msiz) < m->m_pktdat) {
293 MGETHDR(m0, MB_DONTWAIT, MT_HEADER);
295 IF_DROP(&ifp->if_snd);
301 m->m_data += sizeof(struct ip);
302 m->m_len -= sizeof(struct ip);
303 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
304 m0->m_len = msiz + sizeof(struct ip);
305 m0->m_data += max_linkhdr;
306 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
309 } else { /* we have some space left in the old one */
312 m->m_pkthdr.len += msiz;
313 bcopy(ip, mtod(m, caddr_t),
316 ip = mtod(m, struct ip *);
317 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
318 ip->ip_len = ntohs(ip->ip_len) + msiz;
319 } else { /* AF_INET */
320 IF_DROP(&ifp->if_snd);
325 } else if (sc->g_proto == IPPROTO_GRE) {
326 switch (dst->sa_family) {
328 ip = mtod(m, struct ip *);
329 etype = ETHERTYPE_IP;
333 etype = ETHERTYPE_ATALK;
338 etype = ETHERTYPE_NS;
342 IF_DROP(&ifp->if_snd);
344 error = EAFNOSUPPORT;
347 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT);
349 IF_DROP(&ifp->if_snd);
355 if (m == NULL) { /* impossible */
356 IF_DROP(&ifp->if_snd);
361 gh = mtod(m, struct greip *);
362 if (sc->g_proto == IPPROTO_GRE) {
363 /* we don't have any GRE flags for now */
365 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
366 gh->gi_ptype = htons(etype);
369 gh->gi_pr = sc->g_proto;
370 if (sc->g_proto != IPPROTO_MOBILE) {
371 gh->gi_src = sc->g_src;
372 gh->gi_dst = sc->g_dst;
373 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
374 ((struct ip*)gh)->ip_ttl = GRE_TTL;
375 ((struct ip*)gh)->ip_tos = ip->ip_tos;
376 ((struct ip*)gh)->ip_id = ip->ip_id;
377 gh->gi_len = m->m_pkthdr.len;
381 ifp->if_obytes += m->m_pkthdr.len;
383 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL);
392 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
397 lwkt_serialize_enter(ifp->if_serializer);
398 error = gre_output_serialized(ifp, m, dst, rt);
399 lwkt_serialize_exit(ifp->if_serializer);
405 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
407 struct ifreq *ifr = (struct ifreq *)data;
408 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
409 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
410 struct gre_softc *sc = ifp->if_softc;
411 struct sockaddr_in si;
412 struct sockaddr *sa = NULL;
414 struct sockaddr_in sp, sm, dp, dm;
421 ifp->if_flags |= IFF_UP;
426 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
428 if ((ifr->ifr_flags & IFF_LINK0) != 0)
429 sc->g_proto = IPPROTO_GRE;
431 sc->g_proto = IPPROTO_MOBILE;
434 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
436 if (ifr->ifr_mtu < 576) {
440 ifp->if_mtu = ifr->ifr_mtu;
443 ifr->ifr_mtu = sc->sc_if.if_mtu;
447 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
450 error = EAFNOSUPPORT;
453 switch (ifr->ifr_addr.sa_family) {
459 error = EAFNOSUPPORT;
464 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
466 sc->g_proto = ifr->ifr_flags;
467 switch (sc->g_proto) {
469 ifp->if_flags |= IFF_LINK0;
472 ifp->if_flags &= ~IFF_LINK0;
475 error = EPROTONOSUPPORT;
480 ifr->ifr_flags = sc->g_proto;
484 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
487 * set tunnel endpoints, compute a less specific route
488 * to the remote end and mark if as up
491 if (cmd == GRESADDRS)
492 sc->g_src = (satosin(sa))->sin_addr;
493 if (cmd == GRESADDRD)
494 sc->g_dst = (satosin(sa))->sin_addr;
497 if (sc->encap != NULL) {
498 encap_detach(sc->encap);
502 if ((sc->g_src.s_addr != INADDR_ANY) &&
503 (sc->g_dst.s_addr != INADDR_ANY)) {
504 bzero(&sp, sizeof(sp));
505 bzero(&sm, sizeof(sm));
506 bzero(&dp, sizeof(dp));
507 bzero(&dm, sizeof(dm));
508 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
509 sizeof(struct sockaddr_in);
510 sp.sin_family = sm.sin_family = dp.sin_family =
511 dm.sin_family = AF_INET;
512 sp.sin_addr = sc->g_src;
513 dp.sin_addr = sc->g_dst;
514 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
517 sc->encap = encap_attach(AF_INET, sc->g_proto,
518 sintosa(&sp), sintosa(&sm), sintosa(&dp),
519 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
520 &in_gre_protosw : &in_mobile_protosw, sc);
521 if (sc->encap == NULL)
522 kprintf("%s: unable to attach encap\n",
523 if_name(&sc->sc_if));
525 if (sc->route.ro_rt != 0) /* free old route */
526 RTFREE(sc->route.ro_rt);
527 if (gre_compute_route(sc) == 0)
528 ifp->if_flags |= IFF_RUNNING;
530 ifp->if_flags &= ~IFF_RUNNING;
534 memset(&si, 0, sizeof(si));
535 si.sin_family = AF_INET;
536 si.sin_len = sizeof(struct sockaddr_in);
537 si.sin_addr.s_addr = sc->g_src.s_addr;
542 memset(&si, 0, sizeof(si));
543 si.sin_family = AF_INET;
544 si.sin_len = sizeof(struct sockaddr_in);
545 si.sin_addr.s_addr = sc->g_dst.s_addr;
550 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
552 if (aifr->ifra_addr.sin_family != AF_INET ||
553 aifr->ifra_dstaddr.sin_family != AF_INET) {
554 error = EAFNOSUPPORT;
557 if (aifr->ifra_addr.sin_len != sizeof(si) ||
558 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
562 sc->g_src = aifr->ifra_addr.sin_addr;
563 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
565 case SIOCSLIFPHYADDR:
566 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
568 if (lifr->addr.ss_family != AF_INET ||
569 lifr->dstaddr.ss_family != AF_INET) {
570 error = EAFNOSUPPORT;
573 if (lifr->addr.ss_len != sizeof(si) ||
574 lifr->dstaddr.ss_len != sizeof(si)) {
578 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
580 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
583 if ((error = suser_cred(cr, NULL_CRED_OKAY)) != 0)
585 sc->g_src.s_addr = INADDR_ANY;
586 sc->g_dst.s_addr = INADDR_ANY;
588 case SIOCGLIFPHYADDR:
589 if (sc->g_src.s_addr == INADDR_ANY ||
590 sc->g_dst.s_addr == INADDR_ANY) {
591 error = EADDRNOTAVAIL;
594 memset(&si, 0, sizeof(si));
595 si.sin_family = AF_INET;
596 si.sin_len = sizeof(struct sockaddr_in);
597 si.sin_addr.s_addr = sc->g_src.s_addr;
598 memcpy(&lifr->addr, &si, sizeof(si));
599 si.sin_addr.s_addr = sc->g_dst.s_addr;
600 memcpy(&lifr->dstaddr, &si, sizeof(si));
602 case SIOCGIFPSRCADDR:
603 if (sc->g_src.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_src.s_addr;
611 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
613 case SIOCGIFPDSTADDR:
614 if (sc->g_dst.s_addr == INADDR_ANY) {
615 error = EADDRNOTAVAIL;
618 memset(&si, 0, sizeof(si));
619 si.sin_family = AF_INET;
620 si.sin_len = sizeof(struct sockaddr_in);
621 si.sin_addr.s_addr = sc->g_dst.s_addr;
622 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
634 * computes a route to our destination that is not the one
635 * which would be taken by ip_output(), as this one will loop back to
636 * us. If the interface is p2p as a--->b, then a routing entry exists
637 * If we now send a packet to b (e.g. ping b), this will come down here
638 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to
640 * Goal here is to compute a route to b that is less specific than
641 * a-->b. We know that this one exists as in normal operation we have
642 * at least a default route which matches.
645 gre_compute_route(struct gre_softc *sc)
652 memset(ro, 0, sizeof(struct route));
653 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
654 ro->ro_dst.sa_family = AF_INET;
655 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
658 * toggle last bit, so our interface is not found, but a less
659 * specific route. I'd rather like to specify a shorter mask,
660 * but this is not possible. Should work though. XXX
661 * there is a simpler way ...
663 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) {
664 a = ntohl(sc->g_dst.s_addr);
669 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
674 kprintf("%s: searching a route to %s", if_name(&sc->sc_if),
675 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
681 * check if this returned a route at all and this route is no
682 * recursion to ourself
684 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
686 if (ro->ro_rt == NULL)
687 kprintf(" - no route found!\n");
689 kprintf(" - route loops back to ourself!\n");
691 return EADDRNOTAVAIL;
695 * now change it back - else ip_output will just drop
696 * the route and search one to this interface ...
698 if ((sc->sc_if.if_flags & IFF_LINK1) == 0)
699 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
702 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
703 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
711 * do a checksum of a buffer - much like in_cksum, which operates on
715 gre_in_cksum(u_short *p, u_int len)
718 int nwords = len >> 1;
720 while (nwords-- != 0)
728 u.c[0] = *(u_char *)p;
733 /* end-around-carry */
734 sum = (sum >> 16) + (sum & 0xffff);
740 gremodevent(module_t mod, int type, void *data)
748 if_clone_detach(&gre_cloner);
750 while (!LIST_EMPTY(&gre_softc_list))
751 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if);
758 static moduledata_t gre_mod = {
764 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
765 MODULE_VERSION(if_gre, 1);