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.
22 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
24 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
25 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
26 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
36 * Encapsulate L3 protocols into IP
37 * See RFC 2784 (successor of RFC 1701 and 1702) for more details.
38 * If_gre is compatible with Cisco GRE tunnels, so you can
39 * have a NetBSD box as the other end of a tunnel interface of a Cisco
40 * router. See gre(4) for more details.
41 * Also supported: IP in IP encaps (proto 55) as of RFC 2004
44 #include "opt_atalk.h"
46 #include "opt_inet6.h"
48 #include <sys/param.h>
50 #include <sys/kernel.h>
51 #include <sys/libkern.h>
52 #include <sys/malloc.h>
53 #include <sys/module.h>
57 #include <sys/protosw.h>
58 #include <sys/socket.h>
59 #include <sys/sockio.h>
60 #include <sys/sysctl.h>
61 #include <sys/systm.h>
63 #include <net/ethernet.h>
65 #include <net/if_var.h>
66 #include <net/if_clone.h>
67 #include <net/if_types.h>
68 #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/if_gre.h>
88 * It is not easy to calculate the right value for a GRE MTU.
89 * We leave this task to the admin and use the same default that
94 #define MTAG_COOKIE_GRE 1307983903
95 #define MTAG_GRE_NESTING 1
96 struct mtag_gre_nesting {
103 * gre_mtx protects all global variables in if_gre.c.
104 * XXX: gre_softc data not protected yet.
107 static const char grename[] = "gre";
108 static MALLOC_DEFINE(M_GRE, grename, "Generic Routing Encapsulation");
110 struct gre_softc_head gre_softc_list;
112 static int gre_clone_create(struct if_clone *, int, caddr_t);
113 static void gre_clone_destroy(struct ifnet *);
114 static struct if_clone *gre_cloner;
116 static int gre_ioctl(struct ifnet *, u_long, caddr_t);
117 static int gre_output(struct ifnet *, struct mbuf *,
118 const struct sockaddr *, struct route *);
120 static int gre_compute_route(struct gre_softc *sc);
122 static void greattach(void);
125 extern struct domain inetdomain;
126 static const struct protosw in_gre_protosw = {
128 .pr_domain = &inetdomain,
129 .pr_protocol = IPPROTO_GRE,
130 .pr_flags = PR_ATOMIC|PR_ADDR,
131 .pr_input = gre_input,
132 .pr_output = (pr_output_t *)rip_output,
133 .pr_ctlinput = rip_ctlinput,
134 .pr_ctloutput = rip_ctloutput,
135 .pr_usrreqs = &rip_usrreqs
137 static const struct protosw in_mobile_protosw = {
139 .pr_domain = &inetdomain,
140 .pr_protocol = IPPROTO_MOBILE,
141 .pr_flags = PR_ATOMIC|PR_ADDR,
142 .pr_input = gre_mobile_input,
143 .pr_output = (pr_output_t *)rip_output,
144 .pr_ctlinput = rip_ctlinput,
145 .pr_ctloutput = rip_ctloutput,
146 .pr_usrreqs = &rip_usrreqs
150 SYSCTL_DECL(_net_link);
151 static SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0,
152 "Generic Routing Encapsulation");
155 * This macro controls the default upper limitation on nesting of gre tunnels.
156 * Since, setting a large value to this macro with a careless configuration
157 * may introduce system crash, we don't allow any nestings by default.
158 * If you need to configure nested gre tunnels, you can define this macro
159 * in your kernel configuration file. However, if you do so, please be
160 * careful to configure the tunnels so that it won't make a loop.
162 #define MAX_GRE_NEST 1
164 static int max_gre_nesting = MAX_GRE_NEST;
165 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
166 &max_gre_nesting, 0, "Max nested tunnels");
173 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF);
174 LIST_INIT(&gre_softc_list);
175 gre_cloner = if_clone_simple(grename, gre_clone_create,
176 gre_clone_destroy, 0);
180 gre_clone_create(ifc, unit, params)
181 struct if_clone *ifc;
185 struct gre_softc *sc;
187 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO);
189 GRE2IFP(sc) = if_alloc(IFT_TUNNEL);
190 if (GRE2IFP(sc) == NULL) {
195 GRE2IFP(sc)->if_softc = sc;
196 if_initname(GRE2IFP(sc), grename, unit);
198 GRE2IFP(sc)->if_snd.ifq_maxlen = ifqmaxlen;
199 GRE2IFP(sc)->if_addrlen = 0;
200 GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */
201 GRE2IFP(sc)->if_mtu = GREMTU;
202 GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
203 GRE2IFP(sc)->if_output = gre_output;
204 GRE2IFP(sc)->if_ioctl = gre_ioctl;
205 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
206 sc->g_proto = IPPROTO_GRE;
207 GRE2IFP(sc)->if_flags |= IFF_LINK0;
209 sc->gre_fibnum = curthread->td_proc->p_fibnum;
210 sc->wccp_ver = WCCP_V1;
212 if_attach(GRE2IFP(sc));
213 bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t));
215 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
216 mtx_unlock(&gre_mtx);
221 gre_clone_destroy(ifp)
224 struct gre_softc *sc = ifp->if_softc;
227 LIST_REMOVE(sc, sc_list);
228 mtx_unlock(&gre_mtx);
231 if (sc->encap != NULL)
232 encap_detach(sc->encap);
241 * The output routine. Takes a packet and encapsulates it in the protocol
242 * given by sc->g_proto. See also RFC 1701 and RFC 2004
245 gre_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
249 struct gre_softc *sc = ifp->if_softc;
253 struct mtag_gre_nesting *gt;
255 u_short gre_ip_id = 0;
256 uint8_t gre_ip_tos = 0;
258 struct mobile_h mob_h;
263 * gre may cause infinite recursion calls when misconfigured. High
264 * nesting level may cause stack exhaustion. We'll prevent this by
265 * detecting loops and by introducing upper limit.
267 mtag = m_tag_locate(m, MTAG_COOKIE_GRE, MTAG_GRE_NESTING, NULL);
271 gt = (struct mtag_gre_nesting *)(mtag + 1);
273 if (gt->count > min(gt->max,max_gre_nesting)) {
274 printf("%s: hit maximum recursion limit %u on %s\n",
275 __func__, gt->count - 1, ifp->if_xname);
277 error = EIO; /* is there better errno? */
282 for (max = gt->count - 1; max > 0; max--) {
288 printf("%s: detected loop with nexting %u on %s\n",
289 __func__, gt->count-1, ifp->if_xname);
291 error = EIO; /* is there better errno? */
298 * Given that people should NOT increase max_gre_nesting beyond
299 * their real needs, we allocate once per packet rather than
300 * allocating an mtag once per passing through gre.
302 * Note: the sysctl does not actually check for saneness, so we
303 * limit the maximum numbers of possible recursions here.
305 max = imin(max_gre_nesting, 256);
306 /* If someone sets the sysctl <= 0, we want at least 1. */
308 len = sizeof(struct mtag_gre_nesting) +
309 max * sizeof(struct ifnet *);
310 mtag = m_tag_alloc(MTAG_COOKIE_GRE, MTAG_GRE_NESTING, len,
317 gt = (struct mtag_gre_nesting *)(mtag + 1);
322 m_tag_prepend(m, mtag);
325 if (!((ifp->if_flags & IFF_UP) &&
326 (ifp->if_drv_flags & IFF_DRV_RUNNING)) ||
327 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
336 /* BPF writes need to be handled specially. */
337 if (dst->sa_family == AF_UNSPEC)
338 bcopy(dst->sa_data, &af, sizeof(af));
342 if (bpf_peers_present(ifp->if_bpf))
343 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
345 if ((ifp->if_flags & IFF_MONITOR) != 0) {
351 m->m_flags &= ~(M_BCAST|M_MCAST);
353 if (sc->g_proto == IPPROTO_MOBILE) {
358 ip = mtod(m, struct ip *);
361 * RFC2004 specifies that fragmented diagrams shouldn't
364 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
365 _IF_DROP(&ifp->if_snd);
367 error = EINVAL; /* is there better errno? */
370 memset(&mob_h, 0, MOB_H_SIZ_L);
371 mob_h.proto = (ip->ip_p) << 8;
372 mob_h.odst = ip->ip_dst.s_addr;
373 ip->ip_dst.s_addr = sc->g_dst.s_addr;
376 * If the packet comes from our host, we only change
377 * the destination address in the IP header.
378 * Else we also need to save and change the source
380 if (in_hosteq(ip->ip_src, sc->g_src)) {
383 mob_h.proto |= MOB_H_SBIT;
384 mob_h.osrc = ip->ip_src.s_addr;
385 ip->ip_src.s_addr = sc->g_src.s_addr;
388 mob_h.proto = htons(mob_h.proto);
389 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
391 if ((m->m_data - msiz) < m->m_pktdat) {
392 m0 = m_gethdr(M_NOWAIT, MT_DATA);
394 _IF_DROP(&ifp->if_snd);
400 m->m_data += sizeof(struct ip);
401 m->m_len -= sizeof(struct ip);
402 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
403 m0->m_len = msiz + sizeof(struct ip);
404 m0->m_data += max_linkhdr;
405 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
408 } else { /* we have some space left in the old one */
411 m->m_pkthdr.len += msiz;
412 bcopy(ip, mtod(m, caddr_t),
415 ip = mtod(m, struct ip *);
416 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
417 ip->ip_len = htons(ntohs(ip->ip_len) + msiz);
418 } else { /* AF_INET */
419 _IF_DROP(&ifp->if_snd);
424 } else if (sc->g_proto == IPPROTO_GRE) {
427 ip = mtod(m, struct ip *);
428 gre_ip_tos = ip->ip_tos;
429 gre_ip_id = ip->ip_id;
430 if (sc->wccp_ver == WCCP_V2) {
431 extra = sizeof(uint32_t);
432 etype = WCCP_PROTOCOL_TYPE;
434 etype = ETHERTYPE_IP;
439 gre_ip_id = ip_newid();
440 etype = ETHERTYPE_IPV6;
445 etype = ETHERTYPE_ATALK;
449 _IF_DROP(&ifp->if_snd);
451 error = EAFNOSUPPORT;
455 /* Reserve space for GRE header + optional GRE key */
456 int hdrlen = sizeof(struct greip) + extra;
458 hdrlen += sizeof(uint32_t);
459 M_PREPEND(m, hdrlen, M_NOWAIT);
461 _IF_DROP(&ifp->if_snd);
467 if (m == NULL) { /* mbuf allocation failed */
468 _IF_DROP(&ifp->if_snd);
473 M_SETFIB(m, sc->gre_fibnum); /* The envelope may use a different FIB */
475 gh = mtod(m, struct greip *);
476 if (sc->g_proto == IPPROTO_GRE) {
477 uint32_t *options = gh->gi_options;
479 memset((void *)gh, 0, sizeof(struct greip) + extra);
480 gh->gi_ptype = htons(etype);
486 gh->gi_flags |= htons(GRE_KP);
487 *(options++) = htonl(sc->key);
491 gh->gi_pr = sc->g_proto;
492 if (sc->g_proto != IPPROTO_MOBILE) {
493 gh->gi_src = sc->g_src;
494 gh->gi_dst = sc->g_dst;
495 ((struct ip*)gh)->ip_v = IPPROTO_IPV4;
496 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
497 ((struct ip*)gh)->ip_ttl = GRE_TTL;
498 ((struct ip*)gh)->ip_tos = gre_ip_tos;
499 ((struct ip*)gh)->ip_id = gre_ip_id;
500 gh->gi_len = htons(m->m_pkthdr.len);
504 ifp->if_obytes += m->m_pkthdr.len;
506 * Send it off and with IP_FORWARD flag to prevent it from
507 * overwriting the ip_id again. ip_id is already set to the
508 * ip_id of the encapsulated packet.
510 error = ip_output(m, NULL, &sc->route, IP_FORWARDING,
511 (struct ip_moptions *)NULL, (struct inpcb *)NULL);
519 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
521 struct ifreq *ifr = (struct ifreq *)data;
522 struct in_aliasreq *aifr = (struct in_aliasreq *)data;
523 struct gre_softc *sc = ifp->if_softc;
524 struct sockaddr_in si;
525 struct sockaddr *sa = NULL;
527 struct sockaddr_in sp, sm, dp, dm;
535 ifp->if_flags |= IFF_UP;
539 * XXXRW: Isn't this priv_check() redundant to the ifnet
542 if ((error = priv_check(curthread, PRIV_NET_SETIFFLAGS)) != 0)
544 if ((ifr->ifr_flags & IFF_LINK0) != 0)
545 sc->g_proto = IPPROTO_GRE;
547 sc->g_proto = IPPROTO_MOBILE;
548 if ((ifr->ifr_flags & IFF_LINK2) != 0)
549 sc->wccp_ver = WCCP_V2;
551 sc->wccp_ver = WCCP_V1;
555 * XXXRW: Isn't this priv_check() redundant to the ifnet
558 if ((error = priv_check(curthread, PRIV_NET_SETIFMTU)) != 0)
560 if (ifr->ifr_mtu < 576) {
564 ifp->if_mtu = ifr->ifr_mtu;
567 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu;
571 * XXXRW: Isn't this priv_checkr() redundant to the ifnet
574 if ((error = priv_check(curthread, PRIV_NET_ADDMULTI)) != 0)
577 error = EAFNOSUPPORT;
580 switch (ifr->ifr_addr.sa_family) {
590 error = EAFNOSUPPORT;
596 * XXXRW: Isn't this priv_check() redundant to the ifnet
599 if ((error = priv_check(curthread, PRIV_NET_DELIFGROUP)) != 0)
602 error = EAFNOSUPPORT;
605 switch (ifr->ifr_addr.sa_family) {
615 error = EAFNOSUPPORT;
621 * XXXRW: Isn't this priv_check() redundant to the ifnet
624 if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
626 sc->g_proto = ifr->ifr_flags;
627 switch (sc->g_proto) {
629 ifp->if_flags |= IFF_LINK0;
632 ifp->if_flags &= ~IFF_LINK0;
635 error = EPROTONOSUPPORT;
640 ifr->ifr_flags = sc->g_proto;
644 error = priv_check(curthread, PRIV_NET_GRE);
648 * set tunnel endpoints, compute a less specific route
649 * to the remote end and mark if as up
652 if (cmd == GRESADDRS)
653 sc->g_src = (satosin(sa))->sin_addr;
654 if (cmd == GRESADDRD)
655 sc->g_dst = (satosin(sa))->sin_addr;
658 if (sc->encap != NULL) {
659 encap_detach(sc->encap);
663 if ((sc->g_src.s_addr != INADDR_ANY) &&
664 (sc->g_dst.s_addr != INADDR_ANY)) {
665 bzero(&sp, sizeof(sp));
666 bzero(&sm, sizeof(sm));
667 bzero(&dp, sizeof(dp));
668 bzero(&dm, sizeof(dm));
669 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
670 sizeof(struct sockaddr_in);
671 sp.sin_family = sm.sin_family = dp.sin_family =
672 dm.sin_family = AF_INET;
673 sp.sin_addr = sc->g_src;
674 dp.sin_addr = sc->g_dst;
675 sm.sin_addr.s_addr = dm.sin_addr.s_addr =
678 sc->encap = encap_attach(AF_INET, sc->g_proto,
679 sintosa(&sp), sintosa(&sm), sintosa(&dp),
680 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
681 &in_gre_protosw : &in_mobile_protosw, sc);
682 if (sc->encap == NULL)
683 printf("%s: unable to attach encap\n",
684 if_name(GRE2IFP(sc)));
686 if (sc->route.ro_rt != 0) /* free old route */
687 RTFREE(sc->route.ro_rt);
688 if (gre_compute_route(sc) == 0)
689 ifp->if_drv_flags |= IFF_DRV_RUNNING;
691 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
695 memset(&si, 0, sizeof(si));
696 si.sin_family = AF_INET;
697 si.sin_len = sizeof(struct sockaddr_in);
698 si.sin_addr.s_addr = sc->g_src.s_addr;
700 error = prison_if(curthread->td_ucred, sa);
706 memset(&si, 0, sizeof(si));
707 si.sin_family = AF_INET;
708 si.sin_len = sizeof(struct sockaddr_in);
709 si.sin_addr.s_addr = sc->g_dst.s_addr;
711 error = prison_if(curthread->td_ucred, sa);
718 * XXXRW: Isn't this priv_check() redundant to the ifnet
721 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
723 if (aifr->ifra_addr.sin_family != AF_INET ||
724 aifr->ifra_dstaddr.sin_family != AF_INET) {
725 error = EAFNOSUPPORT;
728 if (aifr->ifra_addr.sin_len != sizeof(si) ||
729 aifr->ifra_dstaddr.sin_len != sizeof(si)) {
733 sc->g_src = aifr->ifra_addr.sin_addr;
734 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
738 * XXXRW: Isn't this priv_check() redundant to the ifnet
741 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
743 sc->g_src.s_addr = INADDR_ANY;
744 sc->g_dst.s_addr = INADDR_ANY;
746 case SIOCGIFPSRCADDR:
748 case SIOCGIFPSRCADDR_IN6:
750 if (sc->g_src.s_addr == INADDR_ANY) {
751 error = EADDRNOTAVAIL;
754 memset(&si, 0, sizeof(si));
755 si.sin_family = AF_INET;
756 si.sin_len = sizeof(struct sockaddr_in);
757 si.sin_addr.s_addr = sc->g_src.s_addr;
758 error = prison_if(curthread->td_ucred, (struct sockaddr *)&si);
761 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
763 case SIOCGIFPDSTADDR:
765 case SIOCGIFPDSTADDR_IN6:
767 if (sc->g_dst.s_addr == INADDR_ANY) {
768 error = EADDRNOTAVAIL;
771 memset(&si, 0, sizeof(si));
772 si.sin_family = AF_INET;
773 si.sin_len = sizeof(struct sockaddr_in);
774 si.sin_addr.s_addr = sc->g_dst.s_addr;
775 error = prison_if(curthread->td_ucred, (struct sockaddr *)&si);
778 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
781 error = priv_check(curthread, PRIV_NET_GRE);
784 error = copyin(ifr->ifr_data, &key, sizeof(key));
787 /* adjust MTU for option header */
788 if (key == 0 && sc->key != 0) /* clear */
790 else if (key != 0 && sc->key == 0) /* set */
793 if (ifp->if_mtu + adj < 576) {
801 error = copyout(&sc->key, ifr->ifr_data, sizeof(sc->key));
813 * computes a route to our destination that is not the one
814 * which would be taken by ip_output(), as this one will loop back to
815 * us. If the interface is p2p as a--->b, then a routing entry exists
816 * If we now send a packet to b (e.g. ping b), this will come down here
817 * gets src=a, dst=b tacked on and would from ip_output() sent back to
819 * Goal here is to compute a route to b that is less specific than
820 * a-->b. We know that this one exists as in normal operation we have
821 * at least a default route which matches.
824 gre_compute_route(struct gre_softc *sc)
830 memset(ro, 0, sizeof(struct route));
831 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
832 ro->ro_dst.sa_family = AF_INET;
833 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
836 * toggle last bit, so our interface is not found, but a less
837 * specific route. I'd rather like to specify a shorter mask,
838 * but this is not possible. Should work though. XXX
839 * XXX MRT Use a different FIB for the tunnel to solve this problem.
841 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) {
842 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr ^=
847 printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)),
848 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
851 rtalloc_fib(ro, sc->gre_fibnum);
854 * check if this returned a route at all and this route is no
855 * recursion to ourself
857 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
859 if (ro->ro_rt == NULL)
860 printf(" - no route found!\n");
862 printf(" - route loops back to ourself!\n");
864 return EADDRNOTAVAIL;
868 * now change it back - else ip_output will just drop
869 * the route and search one to this interface ...
871 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0)
872 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
875 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
876 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
884 * do a checksum of a buffer - much like in_cksum, which operates on
888 gre_in_cksum(u_int16_t *p, u_int len)
891 int nwords = len >> 1;
893 while (nwords-- != 0)
901 u.c[0] = *(u_char *)p;
906 /* end-around-carry */
907 sum = (sum >> 16) + (sum & 0xffff);
913 gremodevent(module_t mod, int type, void *data)
921 if_clone_detach(gre_cloner);
922 mtx_destroy(&gre_mtx);
930 static moduledata_t gre_mod = {
936 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
937 MODULE_VERSION(if_gre, 1);