/* $NetBSD: if_gre.c,v 1.21 2001/05/10 01:30:55 itojun 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 * * 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 "gre.h" #if NGRE > 0 #include "opt_inet.h" #include "opt_ns.h" #include "bpfilter.h" #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 /* * XXX this is below the standard MTU of * 1500 Bytes, allowing for headers, * but we should possibly do path mtu discovery * before changing if state to up to find the * correct value */ #define GREMTU 1450 #define LINK_MASK (IFF_LINK0|IFF_LINK1|IFF_LINK2) struct gre_softc_head gre_softc_list; int gre_clone_create __P((struct if_clone *, int)); void gre_clone_destroy __P((struct ifnet *)); struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); void gre_compute_route(struct gre_softc *sc); void greattach __P((int)); /* ARGSUSED */ void greattach(count) int count; { LIST_INIT(&gre_softc_list); if_clone_attach(&gre_cloner); } 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)); sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit); sc->sc_if.if_softc = sc; sc->sc_if.if_type = IFT_OTHER; sc->sc_if.if_addrlen = 4; 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; 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); } void 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); } /* * 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 *inp; u_char ttl, osrc; u_short etype = 0; struct mobile_h mob_h; gh = NULL; inp = NULL; osrc = 0; #if NBPFILTER >0 if (ifp->if_bpf) { /* see comment of other if_foo.c files */ struct mbuf m0; u_int32_t af = dst->sa_family; m0.m_next = m; m0.m_len = 4; m0.m_data = (char *)⁡ bpf_mtap(ifp->if_bpf, &m0); } #endif ttl = 255; if (sc->g_proto == IPPROTO_MOBILE) { if (dst->sa_family == AF_INET) { struct mbuf *m0; int msiz; inp = mtod(m, struct ip *); memset(&mob_h, 0, MOB_H_SIZ_L); mob_h.proto = (inp->ip_p) << 8; mob_h.odst = inp->ip_dst.s_addr; inp->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(inp->ip_src, sc->g_src)) { msiz = MOB_H_SIZ_S; } else { mob_h.proto |= MOB_H_SBIT; mob_h.osrc = inp->ip_src.s_addr; inp->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_short *)&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); return (ENOBUFS); } 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)inp, 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), inp, sizeof(struct ip)); } inp=mtod(m, struct ip *); memcpy((caddr_t)(inp + 1), &mob_h, (unsigned)msiz); NTOHS(inp->ip_len); inp->ip_len += msiz; } else { /* AF_INET */ IF_DROP(&ifp->if_snd); m_freem(m); return (EINVAL); } } else if (sc->g_proto == IPPROTO_GRE) { switch (dst->sa_family) { case AF_INET: inp = mtod(m, struct ip *); ttl = inp->ip_ttl; etype = ETHERTYPE_IP; break; #ifdef NETATALK case AF_APPLETALK: etype = ETHERTYPE_ATALK; break; #endif #ifdef NS case AF_NS: etype = ETHERTYPE_NS; break; #endif default: IF_DROP(&ifp->if_snd); m_freem(m); return (EAFNOSUPPORT); } M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); } else { error = EINVAL; IF_DROP(&ifp->if_snd); m_freem(m); return (error); } if (m == NULL) { IF_DROP(&ifp->if_snd); return (ENOBUFS); } 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 = ttl; ((struct ip*)gh)->ip_tos = inp->ip_tos; gh->gi_len = 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, NULL); 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 ifaddr *ifa = (struct ifaddr *)data; struct ifreq *ifr = (struct ifreq *)data; struct in_ifaddr *ia = (struct in_ifaddr *)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: case SIOCSIFDSTADDR: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; /* * set tunnel endpoints in case that we "only" * have ip over ip encapsulation. This allows to * set tunnel endpoints with ifconfig. */ if (ifa->ifa_addr->sa_family == AF_INET) { sa = ifa->ifa_addr; sc->g_src = (satosin(sa))->sin_addr; sc->g_dst = ia->ia_dstaddr.sin_addr; 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); gre_compute_route(sc); ifp->if_flags |= IFF_UP; } } break; case SIOCSIFFLAGS: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; if ((sc->g_dst.s_addr == INADDR_ANY) || (sc->g_src.s_addr == INADDR_ANY)) ifp->if_flags &= ~IFF_UP; switch (ifr->ifr_flags & LINK_MASK) { case IFF_LINK0: sc->g_proto = IPPROTO_GRE; ifp->if_flags |= IFF_LINK0; ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); break; case IFF_LINK2: sc->g_proto = IPPROTO_MOBILE; ifp->if_flags |= IFF_LINK2; ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1); break; } break; case SIOCSIFMTU: if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; if (ifr->ifr_mtu > GREMTU || 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 ((error = suser(p->p_ucred, &p->p_acflag)) != 0) break; if (ifr == 0) { error = EAFNOSUPPORT; break; } switch (ifr->ifr_addr.sa_family) { #ifdef INET case AF_INET: 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; ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); break; case IPPROTO_MOBILE : ifp->if_flags |= IFF_LINK2; ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); break; default: ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1|IFF_LINK2); } 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; 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); gre_compute_route(sc); ifp->if_flags |= IFF_UP; } break; case GREGADDRS: si.sin_addr.s_addr = sc->g_src.s_addr; sa = sintosa(&si); ifr->ifr_addr = *sa; break; case GREGADDRD: si.sin_addr.s_addr = sc->g_dst.s_addr; sa = sintosa(&si); ifr->ifr_addr = *sa; break; default: error = EINVAL; } 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_ouput() 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. */ void 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 a route to %s", sc->sc_if.if_xname, inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); #endif rtalloc(ro); /* * 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 } /* * do a checksum of a buffer - much like in_cksum, which operates on * mbufs. */ u_short gre_in_cksum(u_short *p, u_int len) { u_int 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