/* $NetBSD: if_gre.c,v 1.57 2005/05/20 16:23:05 christos Exp $ */ /* * Copyright (c) 1998 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Heiko W.Rupp * * IPv6-over-GRE contributed by Gert Doering * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Encapsulate L3 protocols into IP * See RFC 1701 and 1702 for more details. * If_gre is compatible with Cisco GRE tunnels, so you can * have a NetBSD box as the other end of a tunnel interface of a Cisco * router. See gre(4) for more details. * Also supported: IP in IP encaps (proto 55) as of RFC 2004 */ #include __KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.57 2005/05/20 16:23:05 christos Exp $"); #include "opt_inet.h" #include "opt_ns.h" #include "bpfilter.h" #ifdef INET #include #include #include #include #include #include #include #include #if __NetBSD__ #include #endif #include #include #include #include #include #include #ifdef INET #include #include #include #include #include #else #error "Huh? if_gre without inet?" #endif #ifdef NS #include #include #endif #ifdef NETATALK #include #include #include #endif #if NBPFILTER > 0 #include #include #endif #include /* * It is not easy to calculate the right value for a GRE MTU. * We leave this task to the admin and use the same default that * other vendors use. */ #define GREMTU 1476 struct gre_softc_head gre_softc_list; int ip_gre_ttl = GRE_TTL; int gre_clone_create __P((struct if_clone *, int)); int gre_clone_destroy __P((struct ifnet *)); struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); int gre_compute_route(struct gre_softc *sc); int gre_clone_create(ifc, unit) struct if_clone *ifc; int unit; { struct gre_softc *sc; sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); memset(sc, 0, sizeof(struct gre_softc)); snprintf(sc->sc_if.if_xname, sizeof(sc->sc_if.if_xname), "%s%d", ifc->ifc_name, unit); sc->sc_if.if_softc = sc; sc->sc_if.if_type = IFT_TUNNEL; sc->sc_if.if_addrlen = 0; sc->sc_if.if_hdrlen = 24; /* IP + GRE */ sc->sc_if.if_dlt = DLT_NULL; sc->sc_if.if_mtu = GREMTU; sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; sc->sc_if.if_output = gre_output; sc->sc_if.if_ioctl = gre_ioctl; sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; sc->g_proto = IPPROTO_GRE; sc->sc_if.if_flags |= IFF_LINK0; if_attach(&sc->sc_if); if_alloc_sadl(&sc->sc_if); #if NBPFILTER > 0 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); #endif LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); return (0); } int gre_clone_destroy(ifp) struct ifnet *ifp; { struct gre_softc *sc = ifp->if_softc; LIST_REMOVE(sc, sc_list); #if NBPFILTER > 0 bpfdetach(ifp); #endif if_detach(ifp); free(sc, M_DEVBUF); return (0); } /* * The output routine. Takes a packet and encapsulates it in the protocol * given by sc->g_proto. See also RFC 1701 and RFC 2004 */ int gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, struct rtentry *rt) { int error = 0; struct gre_softc *sc = ifp->if_softc; struct greip *gh; struct ip *ip; u_int8_t ip_tos = 0; u_int16_t etype = 0; struct mobile_h mob_h; if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { m_freem(m); error = ENETDOWN; goto end; } gh = NULL; ip = NULL; #if NBPFILTER >0 if (ifp->if_bpf) bpf_mtap_af(ifp->if_bpf, dst->sa_family, m); #endif m->m_flags &= ~(M_BCAST|M_MCAST); if (sc->g_proto == IPPROTO_MOBILE) { if (dst->sa_family == AF_INET) { struct mbuf *m0; int msiz; ip = mtod(m, struct ip *); memset(&mob_h, 0, MOB_H_SIZ_L); mob_h.proto = (ip->ip_p) << 8; mob_h.odst = ip->ip_dst.s_addr; ip->ip_dst.s_addr = sc->g_dst.s_addr; /* * If the packet comes from our host, we only change * the destination address in the IP header. * Else we also need to save and change the source */ if (in_hosteq(ip->ip_src, sc->g_src)) { msiz = MOB_H_SIZ_S; } else { mob_h.proto |= MOB_H_SBIT; mob_h.osrc = ip->ip_src.s_addr; ip->ip_src.s_addr = sc->g_src.s_addr; msiz = MOB_H_SIZ_L; } HTONS(mob_h.proto); mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); if ((m->m_data - msiz) < m->m_pktdat) { /* need new mbuf */ MGETHDR(m0, M_DONTWAIT, MT_HEADER); if (m0 == NULL) { IF_DROP(&ifp->if_snd); m_freem(m); error = ENOBUFS; goto end; } m0->m_next = m; m->m_data += sizeof(struct ip); m->m_len -= sizeof(struct ip); m0->m_pkthdr.len = m->m_pkthdr.len + msiz; m0->m_len = msiz + sizeof(struct ip); m0->m_data += max_linkhdr; memcpy(mtod(m0, caddr_t), (caddr_t)ip, sizeof(struct ip)); m = m0; } else { /* we have some space left in the old one */ m->m_data -= msiz; m->m_len += msiz; m->m_pkthdr.len += msiz; memmove(mtod(m, caddr_t), ip, sizeof(struct ip)); } ip = mtod(m, struct ip *); memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); ip->ip_len = htons(ntohs(ip->ip_len) + msiz); } else { /* AF_INET */ IF_DROP(&ifp->if_snd); m_freem(m); error = EINVAL; goto end; } } else if (sc->g_proto == IPPROTO_GRE) { #ifdef GRE_DEBUG printf( "start gre_output/GRE, dst->sa_family=%d\n", dst->sa_family ); #endif switch (dst->sa_family) { case AF_INET: ip = mtod(m, struct ip *); ip_tos = ip->ip_tos; etype = ETHERTYPE_IP; break; #ifdef NETATALK case AF_APPLETALK: etype = ETHERTYPE_ATALK; break; #endif #ifdef NS case AF_NS: etype = ETHERTYPE_NS; break; #endif #ifdef INET6 case AF_INET6: etype = ETHERTYPE_IPV6; break; #endif default: IF_DROP(&ifp->if_snd); m_freem(m); error = EAFNOSUPPORT; goto end; } M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); } else { IF_DROP(&ifp->if_snd); m_freem(m); error = EINVAL; goto end; } if (m == NULL) { /* impossible */ IF_DROP(&ifp->if_snd); error = ENOBUFS; goto end; } gh = mtod(m, struct greip *); if (sc->g_proto == IPPROTO_GRE) { /* we don't have any GRE flags for now */ memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); gh->gi_ptype = htons(etype); } gh->gi_pr = sc->g_proto; if (sc->g_proto != IPPROTO_MOBILE) { gh->gi_src = sc->g_src; gh->gi_dst = sc->g_dst; ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; ((struct ip*)gh)->ip_ttl = ip_gre_ttl; ((struct ip*)gh)->ip_tos = ip_tos; gh->gi_len = htons(m->m_pkthdr.len); } ifp->if_opackets++; ifp->if_obytes += m->m_pkthdr.len; /* send it off */ error = ip_output(m, NULL, &sc->route, 0, (struct ip_moptions *)NULL, (struct socket *)NULL); end: if (error) ifp->if_oerrors++; return (error); } int gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) { struct proc *p = curproc; /* XXX */ struct ifreq *ifr = (struct ifreq *)data; struct if_laddrreq *lifr = (struct if_laddrreq *)data; struct gre_softc *sc = ifp->if_softc; int s; struct sockaddr_in si; struct sockaddr *sa = NULL; int error; error = 0; s = splnet(); switch (cmd) { case SIOCSIFADDR: ifp->if_flags |= IFF_UP; break; case SIOCSIFDSTADDR: break; case SIOCSIFFLAGS: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; if ((ifr->ifr_flags & IFF_LINK0) != 0) sc->g_proto = IPPROTO_GRE; else sc->g_proto = IPPROTO_MOBILE; break; case SIOCSIFMTU: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; if (ifr->ifr_mtu < 576) { error = EINVAL; break; } ifp->if_mtu = ifr->ifr_mtu; break; case SIOCGIFMTU: ifr->ifr_mtu = sc->sc_if.if_mtu; break; case SIOCADDMULTI: case SIOCDELMULTI: if (ifr == 0) { error = EAFNOSUPPORT; break; } switch (ifr->ifr_addr.sa_family) { #ifdef INET case AF_INET: break; #endif #ifdef INET6 case AF_INET6: break; #endif default: error = EAFNOSUPPORT; break; } break; case GRESPROTO: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; sc->g_proto = ifr->ifr_flags; switch (sc->g_proto) { case IPPROTO_GRE: ifp->if_flags |= IFF_LINK0; break; case IPPROTO_MOBILE: ifp->if_flags &= ~IFF_LINK0; break; default: error = EPROTONOSUPPORT; break; } break; case GREGPROTO: ifr->ifr_flags = sc->g_proto; break; case GRESADDRS: case GRESADDRD: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; /* * set tunnel endpoints, compute a less specific route * to the remote end and mark if as up */ sa = &ifr->ifr_addr; if (cmd == GRESADDRS) sc->g_src = (satosin(sa))->sin_addr; if (cmd == GRESADDRD) sc->g_dst = (satosin(sa))->sin_addr; recompute: if ((sc->g_src.s_addr != INADDR_ANY) && (sc->g_dst.s_addr != INADDR_ANY)) { if (sc->route.ro_rt != 0) /* free old route */ RTFREE(sc->route.ro_rt); if (gre_compute_route(sc) == 0) ifp->if_flags |= IFF_RUNNING; else ifp->if_flags &= ~IFF_RUNNING; } break; case GREGADDRS: memset(&si, 0, sizeof(si)); si.sin_family = AF_INET; si.sin_len = sizeof(struct sockaddr_in); si.sin_addr.s_addr = sc->g_src.s_addr; sa = sintosa(&si); ifr->ifr_addr = *sa; break; case GREGADDRD: memset(&si, 0, sizeof(si)); si.sin_family = AF_INET; si.sin_len = sizeof(struct sockaddr_in); si.sin_addr.s_addr = sc->g_dst.s_addr; sa = sintosa(&si); ifr->ifr_addr = *sa; break; case SIOCSLIFPHYADDR: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; if (lifr->addr.ss_family != AF_INET || lifr->dstaddr.ss_family != AF_INET) { error = EAFNOSUPPORT; break; } if (lifr->addr.ss_len != sizeof(si) || lifr->dstaddr.ss_len != sizeof(si)) { error = EINVAL; break; } sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; sc->g_dst = (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; goto recompute; case SIOCDIFPHYADDR: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; sc->g_src.s_addr = INADDR_ANY; sc->g_dst.s_addr = INADDR_ANY; break; case SIOCGLIFPHYADDR: if (sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { error = EADDRNOTAVAIL; break; } memset(&si, 0, sizeof(si)); si.sin_family = AF_INET; si.sin_len = sizeof(struct sockaddr_in); si.sin_addr.s_addr = sc->g_src.s_addr; memcpy(&lifr->addr, &si, sizeof(si)); si.sin_addr.s_addr = sc->g_dst.s_addr; memcpy(&lifr->dstaddr, &si, sizeof(si)); break; default: error = EINVAL; break; } splx(s); return (error); } /* * computes a route to our destination that is not the one * which would be taken by ip_output(), as this one will loop back to * us. If the interface is p2p as a--->b, then a routing entry exists * If we now send a packet to b (e.g. ping b), this will come down here * gets src=a, dst=b tacked on and would from ip_output() sent back to * if_gre. * Goal here is to compute a route to b that is less specific than * a-->b. We know that this one exists as in normal operation we have * at least a default route which matches. */ int gre_compute_route(struct gre_softc *sc) { struct route *ro; u_int32_t a, b, c; ro = &sc->route; memset(ro, 0, sizeof(struct route)); ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; ro->ro_dst.sa_family = AF_INET; ro->ro_dst.sa_len = sizeof(ro->ro_dst); /* * toggle last bit, so our interface is not found, but a less * specific route. I'd rather like to specify a shorter mask, * but this is not possible. Should work though. XXX * there is a simpler way ... */ if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { a = ntohl(sc->g_dst.s_addr); b = a & 0x01; c = a & 0xfffffffe; b = b ^ 0x01; a = b | c; ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr = htonl(a); } #ifdef DIAGNOSTIC printf("%s: searching for a route to %s", sc->sc_if.if_xname, inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); #endif rtalloc(ro); /* * check if this returned a route at all and this route is no * recursion to ourself */ if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { #ifdef DIAGNOSTIC if (ro->ro_rt == NULL) printf(" - no route found!\n"); else printf(" - route loops back to ourself!\n"); #endif return EADDRNOTAVAIL; } /* * now change it back - else ip_output will just drop * the route and search one to this interface ... */ if ((sc->sc_if.if_flags & IFF_LINK1) == 0) ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; #ifdef DIAGNOSTIC printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); printf("\n"); #endif return 0; } /* * do a checksum of a buffer - much like in_cksum, which operates on * mbufs. */ u_int16_t gre_in_cksum(u_int16_t *p, u_int len) { u_int32_t sum = 0; int nwords = len >> 1; while (nwords-- != 0) sum += *p++; if (len & 1) { union { u_short w; u_char c[2]; } u; u.c[0] = *(u_char *)p; u.c[1] = 0; sum += u.w; } /* end-around-carry */ sum = (sum >> 16) + (sum & 0xffff); sum += (sum >> 16); return (~sum); } #endif void greattach __P((int)); /* ARGSUSED */ void greattach(count) int count; { #ifdef INET LIST_INIT(&gre_softc_list); if_clone_attach(&gre_cloner); #endif }