/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */ /* $FreeBSD$ */ /*- * 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 2784 (successor of 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 "opt_atalk.h" #include "opt_inet.h" #include "opt_inet6.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET #include #include #include #include #include #include #include #else #error "Huh? if_gre without inet?" #endif #include #include #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 #define GRENAME "gre" /* * gre_mtx protects all global variables in if_gre.c. * XXX: gre_softc data not protected yet. */ struct mtx gre_mtx; static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); struct gre_softc_head gre_softc_list; static int gre_clone_create(struct if_clone *, int); static void gre_clone_destroy(struct ifnet *); static int gre_ioctl(struct ifnet *, u_long, caddr_t); static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, struct rtentry *rt); IFC_SIMPLE_DECLARE(gre, 0); static int gre_compute_route(struct gre_softc *sc); static void greattach(void); #ifdef INET extern struct domain inetdomain; static const struct protosw in_gre_protosw = { .pr_type = SOCK_RAW, .pr_domain = &inetdomain, .pr_protocol = IPPROTO_GRE, .pr_flags = PR_ATOMIC|PR_ADDR, .pr_input = gre_input, .pr_output = (pr_output_t *)rip_output, .pr_ctlinput = rip_ctlinput, .pr_ctloutput = rip_ctloutput, .pr_usrreqs = &rip_usrreqs }; static const struct protosw in_mobile_protosw = { .pr_type = SOCK_RAW, .pr_domain = &inetdomain, .pr_protocol = IPPROTO_MOBILE, .pr_flags = PR_ATOMIC|PR_ADDR, .pr_input = gre_mobile_input, .pr_output = (pr_output_t *)rip_output, .pr_ctlinput = rip_ctlinput, .pr_ctloutput = rip_ctloutput, .pr_usrreqs = &rip_usrreqs }; #endif SYSCTL_DECL(_net_link); SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0, "Generic Routing Encapsulation"); #ifndef MAX_GRE_NEST /* * This macro controls the default upper limitation on nesting of gre tunnels. * Since, setting a large value to this macro with a careless configuration * may introduce system crash, we don't allow any nestings by default. * If you need to configure nested gre tunnels, you can define this macro * in your kernel configuration file. However, if you do so, please be * careful to configure the tunnels so that it won't make a loop. */ #define MAX_GRE_NEST 1 #endif static int max_gre_nesting = MAX_GRE_NEST; SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, &max_gre_nesting, 0, "Max nested tunnels"); /* ARGSUSED */ static void greattach(void) { mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF); LIST_INIT(&gre_softc_list); if_clone_attach(&gre_cloner); } static int gre_clone_create(ifc, unit) struct if_clone *ifc; int unit; { struct gre_softc *sc; sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO); GRE2IFP(sc) = if_alloc(IFT_TUNNEL); if (GRE2IFP(sc) == NULL) { free(sc, M_GRE); return (ENOSPC); } GRE2IFP(sc)->if_softc = sc; if_initname(GRE2IFP(sc), ifc->ifc_name, unit); GRE2IFP(sc)->if_snd.ifq_maxlen = IFQ_MAXLEN; GRE2IFP(sc)->if_addrlen = 0; GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */ GRE2IFP(sc)->if_mtu = GREMTU; GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST; GRE2IFP(sc)->if_output = gre_output; GRE2IFP(sc)->if_ioctl = gre_ioctl; sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; sc->g_proto = IPPROTO_GRE; GRE2IFP(sc)->if_flags |= IFF_LINK0; sc->encap = NULL; sc->called = 0; sc->wccp_ver = WCCP_V1; if_attach(GRE2IFP(sc)); bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t)); mtx_lock(&gre_mtx); LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); mtx_unlock(&gre_mtx); return (0); } static void gre_clone_destroy(ifp) struct ifnet *ifp; { struct gre_softc *sc = ifp->if_softc; mtx_lock(&gre_mtx); LIST_REMOVE(sc, sc_list); mtx_unlock(&gre_mtx); #ifdef INET if (sc->encap != NULL) encap_detach(sc->encap); #endif bpfdetach(ifp); if_detach(ifp); if_free(ifp); free(sc, M_GRE); } /* * The output routine. Takes a packet and encapsulates it in the protocol * given by sc->g_proto. See also RFC 1701 and RFC 2004 */ static 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_short ip_id = 0; uint8_t ip_tos = 0; u_int16_t etype = 0; struct mobile_h mob_h; u_int32_t af; /* * gre may cause infinite recursion calls when misconfigured. * We'll prevent this by introducing upper limit. */ if (++(sc->called) > max_gre_nesting) { printf("%s: gre_output: recursively called too many " "times(%d)\n", if_name(GRE2IFP(sc)), sc->called); m_freem(m); error = EIO; /* is there better errno? */ goto end; } if (!((ifp->if_flags & IFF_UP) && (ifp->if_drv_flags & IFF_DRV_RUNNING)) || 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; /* BPF writes need to be handled specially. */ if (dst->sa_family == AF_UNSPEC) { bcopy(dst->sa_data, &af, sizeof(af)); dst->sa_family = af; } if (ifp->if_bpf) { af = dst->sa_family; bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); } 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 *); /* * RFC2004 specifies that fragmented diagrams shouldn't * be encapsulated. */ if ((ip->ip_off & IP_MF) != 0) { _IF_DROP(&ifp->if_snd); m_freem(m); error = EINVAL; /* is there better errno? */ goto end; } 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; } mob_h.proto = 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_DATA); 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; bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); } ip = mtod(m, struct ip *); memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); ip->ip_len = 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) { switch (dst->sa_family) { case AF_INET: ip = mtod(m, struct ip *); ip_tos = ip->ip_tos; ip_id = ip->ip_id; etype = ETHERTYPE_IP; break; #ifdef INET6 case AF_INET6: ip_id = ip_newid(); etype = ETHERTYPE_IPV6; break; #endif #ifdef NETATALK case AF_APPLETALK: etype = ETHERTYPE_ATALK; 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) { /* mbuf allocation failed */ _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, 0, sizeof(struct greip)); 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_v = IPPROTO_IPV4; ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; ((struct ip*)gh)->ip_ttl = GRE_TTL; ((struct ip*)gh)->ip_tos = ip_tos; ((struct ip*)gh)->ip_id = ip_id; gh->gi_len = m->m_pkthdr.len; } ifp->if_opackets++; ifp->if_obytes += m->m_pkthdr.len; /* * Send it off and with IP_FORWARD flag to prevent it from * overwriting the ip_id again. ip_id is already set to the * ip_id of the encapsulated packet. */ error = ip_output(m, NULL, &sc->route, IP_FORWARDING, (struct ip_moptions *)NULL, (struct inpcb *)NULL); end: sc->called = 0; if (error) ifp->if_oerrors++; return (error); } static int gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) { struct ifreq *ifr = (struct ifreq *)data; struct if_laddrreq *lifr = (struct if_laddrreq *)data; struct in_aliasreq *aifr = (struct in_aliasreq *)data; struct gre_softc *sc = ifp->if_softc; int s; struct sockaddr_in si; struct sockaddr *sa = NULL; int error; struct sockaddr_in sp, sm, dp, dm; error = 0; s = splnet(); switch (cmd) { case SIOCSIFADDR: ifp->if_flags |= IFF_UP; break; case SIOCSIFDSTADDR: break; case SIOCSIFFLAGS: if ((error = suser(curthread)) != 0) break; if ((ifr->ifr_flags & IFF_LINK0) != 0) sc->g_proto = IPPROTO_GRE; else sc->g_proto = IPPROTO_MOBILE; if ((ifr->ifr_flags & IFF_LINK2) != 0) sc->wccp_ver = WCCP_V2; else sc->wccp_ver = WCCP_V1; goto recompute; case SIOCSIFMTU: if ((error = suser(curthread)) != 0) break; if (ifr->ifr_mtu < 576) { error = EINVAL; break; } ifp->if_mtu = ifr->ifr_mtu; break; case SIOCGIFMTU: ifr->ifr_mtu = GRE2IFP(sc)->if_mtu; break; case SIOCADDMULTI: case SIOCDELMULTI: if ((error = suser(curthread)) != 0) break; 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(curthread)) != 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; } goto recompute; case GREGPROTO: ifr->ifr_flags = sc->g_proto; break; case GRESADDRS: case GRESADDRD: if ((error = suser(curthread)) != 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: #ifdef INET if (sc->encap != NULL) { encap_detach(sc->encap); sc->encap = NULL; } #endif if ((sc->g_src.s_addr != INADDR_ANY) && (sc->g_dst.s_addr != INADDR_ANY)) { bzero(&sp, sizeof(sp)); bzero(&sm, sizeof(sm)); bzero(&dp, sizeof(dp)); bzero(&dm, sizeof(dm)); sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = sizeof(struct sockaddr_in); sp.sin_family = sm.sin_family = dp.sin_family = dm.sin_family = AF_INET; sp.sin_addr = sc->g_src; dp.sin_addr = sc->g_dst; sm.sin_addr.s_addr = dm.sin_addr.s_addr = INADDR_BROADCAST; #ifdef INET sc->encap = encap_attach(AF_INET, sc->g_proto, sintosa(&sp), sintosa(&sm), sintosa(&dp), sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? &in_gre_protosw : &in_mobile_protosw, sc); if (sc->encap == NULL) printf("%s: unable to attach encap\n", if_name(GRE2IFP(sc))); #endif if (sc->route.ro_rt != 0) /* free old route */ RTFREE(sc->route.ro_rt); if (gre_compute_route(sc) == 0) ifp->if_drv_flags |= IFF_DRV_RUNNING; else ifp->if_drv_flags &= ~IFF_DRV_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 SIOCSIFPHYADDR: if ((error = suser(curthread)) != 0) break; if (aifr->ifra_addr.sin_family != AF_INET || aifr->ifra_dstaddr.sin_family != AF_INET) { error = EAFNOSUPPORT; break; } if (aifr->ifra_addr.sin_len != sizeof(si) || aifr->ifra_dstaddr.sin_len != sizeof(si)) { error = EINVAL; break; } sc->g_src = aifr->ifra_addr.sin_addr; sc->g_dst = aifr->ifra_dstaddr.sin_addr; goto recompute; case SIOCSLIFPHYADDR: if ((error = suser(curthread)) != 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(&lifr->addr))->sin_addr; sc->g_dst = (satosin(&lifr->dstaddr))->sin_addr; goto recompute; case SIOCDIFPHYADDR: if ((error = suser(curthread)) != 0) break; sc->g_src.s_addr = INADDR_ANY; sc->g_dst.s_addr = INADDR_ANY; goto recompute; 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; case SIOCGIFPSRCADDR: #ifdef INET6 case SIOCGIFPSRCADDR_IN6: #endif if (sc->g_src.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; bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); break; case SIOCGIFPDSTADDR: #ifdef INET6 case SIOCGIFPDSTADDR_IN6: #endif if (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_dst.s_addr; bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 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. */ static 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 ((GRE2IFP(sc)->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", if_name(GRE2IFP(sc)), 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 ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; #ifdef DIAGNOSTIC printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 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); } static int gremodevent(module_t mod, int type, void *data) { switch (type) { case MOD_LOAD: greattach(); break; case MOD_UNLOAD: if_clone_detach(&gre_cloner); mtx_destroy(&gre_mtx); break; default: return EOPNOTSUPP; } return 0; } static moduledata_t gre_mod = { "if_gre", gremodevent, 0 }; DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); MODULE_VERSION(if_gre, 1);