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>
62 #include <sys/protosw.h>
63 #include <sys/socket.h>
64 #include <sys/sockio.h>
65 #include <sys/sysctl.h>
66 #include <sys/systm.h>
68 #include <net/ethernet.h>
70 #include <net/if_clone.h>
71 #include <net/if_types.h>
72 #include <net/route.h>
75 #include <netinet/in.h>
76 #include <netinet/in_systm.h>
77 #include <netinet/in_var.h>
78 #include <netinet/ip.h>
79 #include <netinet/ip_gre.h>
80 #include <netinet/ip_var.h>
81 #include <netinet/ip_encap.h>
83 #error "Huh? if_gre without inet?"
88 #include <net/if_gre.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
100 * gre_mtx protects all global variables in if_gre.c.
101 * XXX: gre_softc data not protected yet.
104 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
106 struct gre_softc_head gre_softc_list;
108 static int gre_clone_create(struct if_clone *, int, caddr_t);
109 static void gre_clone_destroy(struct ifnet *);
110 static int gre_ioctl(struct ifnet *, u_long, caddr_t);
111 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
114 IFC_SIMPLE_DECLARE(gre, 0);
116 static int gre_compute_route(struct gre_softc *sc);
118 static void greattach(void);
121 extern struct domain inetdomain;
122 static const struct protosw in_gre_protosw = {
124 .pr_domain = &inetdomain,
125 .pr_protocol = IPPROTO_GRE,
126 .pr_flags = PR_ATOMIC|PR_ADDR,
127 .pr_input = gre_input,
128 .pr_output = (pr_output_t *)rip_output,
129 .pr_ctlinput = rip_ctlinput,
130 .pr_ctloutput = rip_ctloutput,
131 .pr_usrreqs = &rip_usrreqs
133 static const struct protosw in_mobile_protosw = {
135 .pr_domain = &inetdomain,
136 .pr_protocol = IPPROTO_MOBILE,
137 .pr_flags = PR_ATOMIC|PR_ADDR,
138 .pr_input = gre_mobile_input,
139 .pr_output = (pr_output_t *)rip_output,
140 .pr_ctlinput = rip_ctlinput,
141 .pr_ctloutput = rip_ctloutput,
142 .pr_usrreqs = &rip_usrreqs
146 SYSCTL_DECL(_net_link);
147 SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0,
148 "Generic Routing Encapsulation");
151 * This macro controls the default upper limitation on nesting of gre tunnels.
152 * Since, setting a large value to this macro with a careless configuration
153 * may introduce system crash, we don't allow any nestings by default.
154 * If you need to configure nested gre tunnels, you can define this macro
155 * in your kernel configuration file. However, if you do so, please be
156 * careful to configure the tunnels so that it won't make a loop.
158 #define MAX_GRE_NEST 1
160 static int max_gre_nesting = MAX_GRE_NEST;
161 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
162 &max_gre_nesting, 0, "Max nested tunnels");
169 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF);
170 LIST_INIT(&gre_softc_list);
171 if_clone_attach(&gre_cloner);
175 gre_clone_create(ifc, unit, params)
176 struct if_clone *ifc;
180 struct gre_softc *sc;
182 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO);
184 GRE2IFP(sc) = if_alloc(IFT_TUNNEL);
185 if (GRE2IFP(sc) == NULL) {
190 GRE2IFP(sc)->if_softc = sc;
191 if_initname(GRE2IFP(sc), ifc->ifc_name, unit);
193 GRE2IFP(sc)->if_snd.ifq_maxlen = IFQ_MAXLEN;
194 GRE2IFP(sc)->if_addrlen = 0;
195 GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */
196 GRE2IFP(sc)->if_mtu = GREMTU;
197 GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
198 GRE2IFP(sc)->if_output = gre_output;
199 GRE2IFP(sc)->if_ioctl = gre_ioctl;
200 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
201 sc->g_proto = IPPROTO_GRE;
202 GRE2IFP(sc)->if_flags |= IFF_LINK0;
205 sc->gre_fibnum = curthread->td_proc->p_fibnum;
206 sc->wccp_ver = WCCP_V1;
208 if_attach(GRE2IFP(sc));
209 bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t));
211 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
212 mtx_unlock(&gre_mtx);
217 gre_clone_destroy(ifp)
220 struct gre_softc *sc = ifp->if_softc;
223 LIST_REMOVE(sc, sc_list);
224 mtx_unlock(&gre_mtx);
227 if (sc->encap != NULL)
228 encap_detach(sc->encap);
237 * The output routine. Takes a packet and encapsulates it in the protocol
238 * given by sc->g_proto. See also RFC 1701 and RFC 2004
241 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
245 INIT_VNET_INET(ifp->if_vnet);
248 struct gre_softc *sc = ifp->if_softc;
251 u_short gre_ip_id = 0;
252 uint8_t gre_ip_tos = 0;
254 struct mobile_h mob_h;
259 * gre may cause infinite recursion calls when misconfigured.
260 * We'll prevent this by introducing upper limit.
262 if (++(sc->called) > max_gre_nesting) {
263 printf("%s: gre_output: recursively called too many "
264 "times(%d)\n", if_name(GRE2IFP(sc)), sc->called);
266 error = EIO; /* is there better errno? */
270 if (!((ifp->if_flags & IFF_UP) &&
271 (ifp->if_drv_flags & IFF_DRV_RUNNING)) ||
272 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
281 /* BPF writes need to be handled specially. */
282 if (dst->sa_family == AF_UNSPEC) {
283 bcopy(dst->sa_data, &af, sizeof(af));
287 if (bpf_peers_present(ifp->if_bpf)) {
289 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
292 m->m_flags &= ~(M_BCAST|M_MCAST);
294 if (sc->g_proto == IPPROTO_MOBILE) {
295 if (dst->sa_family == AF_INET) {
299 ip = mtod(m, struct ip *);
302 * RFC2004 specifies that fragmented diagrams shouldn't
305 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
306 _IF_DROP(&ifp->if_snd);
308 error = EINVAL; /* is there better errno? */
311 memset(&mob_h, 0, MOB_H_SIZ_L);
312 mob_h.proto = (ip->ip_p) << 8;
313 mob_h.odst = ip->ip_dst.s_addr;
314 ip->ip_dst.s_addr = sc->g_dst.s_addr;
317 * If the packet comes from our host, we only change
318 * the destination address in the IP header.
319 * Else we also need to save and change the source
321 if (in_hosteq(ip->ip_src, sc->g_src)) {
324 mob_h.proto |= MOB_H_SBIT;
325 mob_h.osrc = ip->ip_src.s_addr;
326 ip->ip_src.s_addr = sc->g_src.s_addr;
329 mob_h.proto = htons(mob_h.proto);
330 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
332 if ((m->m_data - msiz) < m->m_pktdat) {
334 MGETHDR(m0, M_DONTWAIT, MT_DATA);
336 _IF_DROP(&ifp->if_snd);
342 m->m_data += sizeof(struct ip);
343 m->m_len -= sizeof(struct ip);
344 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
345 m0->m_len = msiz + sizeof(struct ip);
346 m0->m_data += max_linkhdr;
347 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
350 } else { /* we have some space left in the old one */
353 m->m_pkthdr.len += msiz;
354 bcopy(ip, mtod(m, caddr_t),
357 ip = mtod(m, struct ip *);
358 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
359 ip->ip_len = ntohs(ip->ip_len) + msiz;
360 } else { /* AF_INET */
361 _IF_DROP(&ifp->if_snd);
366 } else if (sc->g_proto == IPPROTO_GRE) {
367 switch (dst->sa_family) {
369 ip = mtod(m, struct ip *);
370 gre_ip_tos = ip->ip_tos;
371 gre_ip_id = ip->ip_id;
372 if (sc->wccp_ver == WCCP_V2) {
373 extra = sizeof(uint32_t);
374 etype = WCCP_PROTOCOL_TYPE;
376 etype = ETHERTYPE_IP;
381 gre_ip_id = ip_newid();
382 etype = ETHERTYPE_IPV6;
387 etype = ETHERTYPE_ATALK;
391 _IF_DROP(&ifp->if_snd);
393 error = EAFNOSUPPORT;
397 /* Reserve space for GRE header + optional GRE key */
398 int hdrlen = sizeof(struct greip) + extra;
400 hdrlen += sizeof(uint32_t);
401 M_PREPEND(m, hdrlen, M_DONTWAIT);
403 _IF_DROP(&ifp->if_snd);
409 if (m == NULL) { /* mbuf allocation failed */
410 _IF_DROP(&ifp->if_snd);
415 M_SETFIB(m, sc->gre_fibnum); /* The envelope may use a different FIB */
417 gh = mtod(m, struct greip *);
418 if (sc->g_proto == IPPROTO_GRE) {
419 uint32_t *options = gh->gi_options;
421 memset((void *)gh, 0, sizeof(struct greip) + extra);
422 gh->gi_ptype = htons(etype);
428 gh->gi_flags |= htons(GRE_KP);
429 *(options++) = htonl(sc->key);
433 gh->gi_pr = sc->g_proto;
434 if (sc->g_proto != IPPROTO_MOBILE) {
435 gh->gi_src = sc->g_src;
436 gh->gi_dst = sc->g_dst;
437 ((struct ip*)gh)->ip_v = IPPROTO_IPV4;
438 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
439 ((struct ip*)gh)->ip_ttl = GRE_TTL;
440 ((struct ip*)gh)->ip_tos = gre_ip_tos;
441 ((struct ip*)gh)->ip_id = gre_ip_id;
442 gh->gi_len = m->m_pkthdr.len;
446 ifp->if_obytes += m->m_pkthdr.len;
448 * Send it off and with IP_FORWARD flag to prevent it from
449 * overwriting the ip_id again. ip_id is already set to the
450 * ip_id of the encapsulated packet.
452 error = ip_output(m, NULL, &sc->route, IP_FORWARDING,
453 (struct ip_moptions *)NULL, (struct inpcb *)NULL);
462 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
464 struct ifreq *ifr = (struct ifreq *)data;
465 struct if_laddrreq *lifr = (struct if_laddrreq *)data;
466 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
467 struct gre_softc *sc = ifp->if_softc;
469 struct sockaddr_in si;
470 struct sockaddr *sa = NULL;
472 struct sockaddr_in sp, sm, dp, dm;
481 ifp->if_flags |= IFF_UP;
487 * XXXRW: Isn't this priv_check() redundant to the ifnet
490 if ((error = priv_check(curthread, PRIV_NET_SETIFFLAGS)) != 0)
492 if ((ifr->ifr_flags & IFF_LINK0) != 0)
493 sc->g_proto = IPPROTO_GRE;
495 sc->g_proto = IPPROTO_MOBILE;
496 if ((ifr->ifr_flags & IFF_LINK2) != 0)
497 sc->wccp_ver = WCCP_V2;
499 sc->wccp_ver = WCCP_V1;
503 * XXXRW: Isn't this priv_check() redundant to the ifnet
506 if ((error = priv_check(curthread, PRIV_NET_SETIFMTU)) != 0)
508 if (ifr->ifr_mtu < 576) {
512 ifp->if_mtu = ifr->ifr_mtu;
515 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu;
519 * XXXRW: Isn't this priv_checkr() redundant to the ifnet
522 if ((error = priv_check(curthread, PRIV_NET_ADDMULTI)) != 0)
525 error = EAFNOSUPPORT;
528 switch (ifr->ifr_addr.sa_family) {
538 error = EAFNOSUPPORT;
544 * XXXRW: Isn't this priv_check() redundant to the ifnet
547 if ((error = priv_check(curthread, PRIV_NET_DELIFGROUP)) != 0)
550 error = EAFNOSUPPORT;
553 switch (ifr->ifr_addr.sa_family) {
563 error = EAFNOSUPPORT;
569 * XXXRW: Isn't this priv_check() redundant to the ifnet
572 if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
574 sc->g_proto = ifr->ifr_flags;
575 switch (sc->g_proto) {
577 ifp->if_flags |= IFF_LINK0;
580 ifp->if_flags &= ~IFF_LINK0;
583 error = EPROTONOSUPPORT;
588 ifr->ifr_flags = sc->g_proto;
592 error = priv_check(curthread, PRIV_NET_GRE);
596 * set tunnel endpoints, compute a less specific route
597 * to the remote end and mark if as up
600 if (cmd == GRESADDRS)
601 sc->g_src = (satosin(sa))->sin_addr;
602 if (cmd == GRESADDRD)
603 sc->g_dst = (satosin(sa))->sin_addr;
606 if (sc->encap != NULL) {
607 encap_detach(sc->encap);
611 if ((sc->g_src.s_addr != INADDR_ANY) &&
612 (sc->g_dst.s_addr != INADDR_ANY)) {
613 bzero(&sp, sizeof(sp));
614 bzero(&sm, sizeof(sm));
615 bzero(&dp, sizeof(dp));
616 bzero(&dm, sizeof(dm));
617 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
618 sizeof(struct sockaddr_in);
619 sp.sin_family = sm.sin_family = dp.sin_family =
620 dm.sin_family = AF_INET;
621 sp.sin_addr = sc->g_src;
622 dp.sin_addr = sc->g_dst;
623 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
626 sc->encap = encap_attach(AF_INET, sc->g_proto,
627 sintosa(&sp), sintosa(&sm), sintosa(&dp),
628 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
629 &in_gre_protosw : &in_mobile_protosw, sc);
630 if (sc->encap == NULL)
631 printf("%s: unable to attach encap\n",
632 if_name(GRE2IFP(sc)));
634 if (sc->route.ro_rt != 0) /* free old route */
635 RTFREE(sc->route.ro_rt);
636 if (gre_compute_route(sc) == 0)
637 ifp->if_drv_flags |= IFF_DRV_RUNNING;
639 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
643 memset(&si, 0, sizeof(si));
644 si.sin_family = AF_INET;
645 si.sin_len = sizeof(struct sockaddr_in);
646 si.sin_addr.s_addr = sc->g_src.s_addr;
651 memset(&si, 0, sizeof(si));
652 si.sin_family = AF_INET;
653 si.sin_len = sizeof(struct sockaddr_in);
654 si.sin_addr.s_addr = sc->g_dst.s_addr;
660 * XXXRW: Isn't this priv_check() redundant to the ifnet
663 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
665 if (aifr->ifra_addr.sin_family != AF_INET ||
666 aifr->ifra_dstaddr.sin_family != AF_INET) {
667 error = EAFNOSUPPORT;
670 if (aifr->ifra_addr.sin_len != sizeof(si) ||
671 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
675 sc->g_src = aifr->ifra_addr.sin_addr;
676 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
678 case SIOCSLIFPHYADDR:
680 * XXXRW: Isn't this priv_check() redundant to the ifnet
683 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
685 if (lifr->addr.ss_family != AF_INET ||
686 lifr->dstaddr.ss_family != AF_INET) {
687 error = EAFNOSUPPORT;
690 if (lifr->addr.ss_len != sizeof(si) ||
691 lifr->dstaddr.ss_len != sizeof(si)) {
695 sc->g_src = (satosin(&lifr->addr))->sin_addr;
697 (satosin(&lifr->dstaddr))->sin_addr;
701 * XXXRW: Isn't this priv_check() redundant to the ifnet
704 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
706 sc->g_src.s_addr = INADDR_ANY;
707 sc->g_dst.s_addr = INADDR_ANY;
709 case SIOCGLIFPHYADDR:
710 if (sc->g_src.s_addr == INADDR_ANY ||
711 sc->g_dst.s_addr == INADDR_ANY) {
712 error = EADDRNOTAVAIL;
715 memset(&si, 0, sizeof(si));
716 si.sin_family = AF_INET;
717 si.sin_len = sizeof(struct sockaddr_in);
718 si.sin_addr.s_addr = sc->g_src.s_addr;
719 memcpy(&lifr->addr, &si, sizeof(si));
720 si.sin_addr.s_addr = sc->g_dst.s_addr;
721 memcpy(&lifr->dstaddr, &si, sizeof(si));
723 case SIOCGIFPSRCADDR:
725 case SIOCGIFPSRCADDR_IN6:
727 if (sc->g_src.s_addr == INADDR_ANY) {
728 error = EADDRNOTAVAIL;
731 memset(&si, 0, sizeof(si));
732 si.sin_family = AF_INET;
733 si.sin_len = sizeof(struct sockaddr_in);
734 si.sin_addr.s_addr = sc->g_src.s_addr;
735 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
737 case SIOCGIFPDSTADDR:
739 case SIOCGIFPDSTADDR_IN6:
741 if (sc->g_dst.s_addr == INADDR_ANY) {
742 error = EADDRNOTAVAIL;
745 memset(&si, 0, sizeof(si));
746 si.sin_family = AF_INET;
747 si.sin_len = sizeof(struct sockaddr_in);
748 si.sin_addr.s_addr = sc->g_dst.s_addr;
749 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
752 error = priv_check(curthread, PRIV_NET_GRE);
755 error = copyin(ifr->ifr_data, &key, sizeof(key));
758 /* adjust MTU for option header */
759 if (key == 0 && sc->key != 0) /* clear */
761 else if (key != 0 && sc->key == 0) /* set */
764 if (ifp->if_mtu + adj < 576) {
772 error = copyout(&sc->key, ifr->ifr_data, sizeof(sc->key));
785 * computes a route to our destination that is not the one
786 * which would be taken by ip_output(), as this one will loop back to
787 * us. If the interface is p2p as a--->b, then a routing entry exists
788 * If we now send a packet to b (e.g. ping b), this will come down here
789 * gets src=a, dst=b tacked on and would from ip_output() sent back to
791 * Goal here is to compute a route to b that is less specific than
792 * a-->b. We know that this one exists as in normal operation we have
793 * at least a default route which matches.
796 gre_compute_route(struct gre_softc *sc)
802 memset(ro, 0, sizeof(struct route));
803 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
804 ro->ro_dst.sa_family = AF_INET;
805 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
808 * toggle last bit, so our interface is not found, but a less
809 * specific route. I'd rather like to specify a shorter mask,
810 * but this is not possible. Should work though. XXX
811 * XXX MRT Use a different FIB for the tunnel to solve this problem.
813 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) {
814 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr ^=
819 printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)),
820 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
823 rtalloc_fib(ro, sc->gre_fibnum);
826 * check if this returned a route at all and this route is no
827 * recursion to ourself
829 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
831 if (ro->ro_rt == NULL)
832 printf(" - no route found!\n");
834 printf(" - route loops back to ourself!\n");
836 return EADDRNOTAVAIL;
840 * now change it back - else ip_output will just drop
841 * the route and search one to this interface ...
843 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0)
844 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
847 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
848 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
856 * do a checksum of a buffer - much like in_cksum, which operates on
860 gre_in_cksum(u_int16_t *p, u_int len)
863 int nwords = len >> 1;
865 while (nwords-- != 0)
873 u.c[0] = *(u_char *)p;
878 /* end-around-carry */
879 sum = (sum >> 16) + (sum & 0xffff);
885 gremodevent(module_t mod, int type, void *data)
893 if_clone_detach(&gre_cloner);
894 mtx_destroy(&gre_mtx);
902 static moduledata_t gre_mod = {
908 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
909 MODULE_VERSION(if_gre, 1);