/* $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. * * 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 #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 /* * 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 MTAG_COOKIE_GRE 1307983903 #define MTAG_GRE_NESTING 1 struct mtag_gre_nesting { uint16_t count; uint16_t max; struct ifnet *ifp[]; }; /* * gre_mtx protects all global variables in if_gre.c. * XXX: gre_softc data not protected yet. */ struct mtx gre_mtx; static const char grename[] = "gre"; 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, caddr_t); static void gre_clone_destroy(struct ifnet *); static struct if_clone *gre_cloner; static int gre_ioctl(struct ifnet *, u_long, caddr_t); static int gre_output(struct ifnet *, struct mbuf *, const struct sockaddr *, struct route *); 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); static 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); gre_cloner = if_clone_simple(grename, gre_clone_create, gre_clone_destroy, 0); } static int gre_clone_create(ifc, unit, params) struct if_clone *ifc; int unit; caddr_t params; { 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), grename, unit); GRE2IFP(sc)->if_snd.ifq_maxlen = ifqmaxlen; 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->gre_fibnum = curthread->td_proc->p_fibnum; sc->wccp_ver = WCCP_V1; sc->key = 0; 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, const struct sockaddr *dst, struct route *ro) { int error = 0; struct gre_softc *sc = ifp->if_softc; struct greip *gh; struct ip *ip; struct m_tag *mtag; struct mtag_gre_nesting *gt; size_t len; u_short gre_ip_id = 0; uint8_t gre_ip_tos = 0; u_int16_t etype = 0; struct mobile_h mob_h; u_int32_t af; int extra = 0, max; /* * gre may cause infinite recursion calls when misconfigured. High * nesting level may cause stack exhaustion. We'll prevent this by * detecting loops and by introducing upper limit. */ mtag = m_tag_locate(m, MTAG_COOKIE_GRE, MTAG_GRE_NESTING, NULL); if (mtag != NULL) { struct ifnet **ifp2; gt = (struct mtag_gre_nesting *)(mtag + 1); gt->count++; if (gt->count > min(gt->max,max_gre_nesting)) { printf("%s: hit maximum recursion limit %u on %s\n", __func__, gt->count - 1, ifp->if_xname); m_freem(m); error = EIO; /* is there better errno? */ goto end; } ifp2 = gt->ifp; for (max = gt->count - 1; max > 0; max--) { if (*ifp2 == ifp) break; ifp2++; } if (*ifp2 == ifp) { printf("%s: detected loop with nexting %u on %s\n", __func__, gt->count-1, ifp->if_xname); m_freem(m); error = EIO; /* is there better errno? */ goto end; } *ifp2 = ifp; } else { /* * Given that people should NOT increase max_gre_nesting beyond * their real needs, we allocate once per packet rather than * allocating an mtag once per passing through gre. * * Note: the sysctl does not actually check for saneness, so we * limit the maximum numbers of possible recursions here. */ max = imin(max_gre_nesting, 256); /* If someone sets the sysctl <= 0, we want at least 1. */ max = imax(max, 1); len = sizeof(struct mtag_gre_nesting) + max * sizeof(struct ifnet *); mtag = m_tag_alloc(MTAG_COOKIE_GRE, MTAG_GRE_NESTING, len, M_NOWAIT); if (mtag == NULL) { m_freem(m); error = ENOMEM; goto end; } gt = (struct mtag_gre_nesting *)(mtag + 1); bzero(gt, len); gt->count = 1; gt->max = max; *gt->ifp = ifp; m_tag_prepend(m, mtag); } 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)); else af = dst->sa_family; if (bpf_peers_present(ifp->if_bpf)) bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); if ((ifp->if_flags & IFF_MONITOR) != 0) { m_freem(m); error = ENETDOWN; goto end; } m->m_flags &= ~(M_BCAST|M_MCAST); if (sc->g_proto == IPPROTO_MOBILE) { if (af == 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 & htons(IP_MF | IP_OFFMASK)) { _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) { m0 = m_gethdr(M_NOWAIT, 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 = 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) { switch (af) { case AF_INET: ip = mtod(m, struct ip *); gre_ip_tos = ip->ip_tos; gre_ip_id = ip->ip_id; if (sc->wccp_ver == WCCP_V2) { extra = sizeof(uint32_t); etype = WCCP_PROTOCOL_TYPE; } else { etype = ETHERTYPE_IP; } break; #ifdef INET6 case AF_INET6: gre_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; } /* Reserve space for GRE header + optional GRE key */ int hdrlen = sizeof(struct greip) + extra; if (sc->key) hdrlen += sizeof(uint32_t); M_PREPEND(m, hdrlen, M_NOWAIT); } 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; } M_SETFIB(m, sc->gre_fibnum); /* The envelope may use a different FIB */ gh = mtod(m, struct greip *); if (sc->g_proto == IPPROTO_GRE) { uint32_t *options = gh->gi_options; memset((void *)gh, 0, sizeof(struct greip) + extra); gh->gi_ptype = htons(etype); gh->gi_flags = 0; /* Add key option */ if (sc->key) { gh->gi_flags |= htons(GRE_KP); *(options++) = htonl(sc->key); } } 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 = gre_ip_tos; ((struct ip*)gh)->ip_id = gre_ip_id; gh->gi_len = htons(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: 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; struct sockaddr_in si; struct sockaddr *sa = NULL; int error, adj; struct sockaddr_in sp, sm, dp, dm; uint32_t key; error = 0; adj = 0; switch (cmd) { case SIOCSIFADDR: ifp->if_flags |= IFF_UP; break; case SIOCSIFFLAGS: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_SETIFFLAGS)) != 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: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_SETIFMTU)) != 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: /* * XXXRW: Isn't this priv_checkr() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_ADDMULTI)) != 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 SIOCDELMULTI: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_DELIFGROUP)) != 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: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_GRE)) != 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: error = priv_check(curthread, PRIV_NET_GRE); if (error) return (error); /* * 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); error = prison_if(curthread->td_ucred, sa); if (error != 0) break; 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); error = prison_if(curthread->td_ucred, sa); if (error != 0) break; ifr->ifr_addr = *sa; break; case SIOCSIFPHYADDR: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 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: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 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: /* * XXXRW: Isn't this priv_check() redundant to the ifnet * layer check? */ if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 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; error = prison_if(curthread->td_ucred, (struct sockaddr *)&si); if (error != 0) break; memcpy(&lifr->addr, &si, sizeof(si)); si.sin_addr.s_addr = sc->g_dst.s_addr; error = prison_if(curthread->td_ucred, (struct sockaddr *)&si); if (error != 0) break; 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; error = prison_if(curthread->td_ucred, (struct sockaddr *)&si); if (error != 0) break; 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; error = prison_if(curthread->td_ucred, (struct sockaddr *)&si); if (error != 0) break; bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); break; case GRESKEY: error = priv_check(curthread, PRIV_NET_GRE); if (error) break; error = copyin(ifr->ifr_data, &key, sizeof(key)); if (error) break; /* adjust MTU for option header */ if (key == 0 && sc->key != 0) /* clear */ adj += sizeof(key); else if (key != 0 && sc->key == 0) /* set */ adj -= sizeof(key); if (ifp->if_mtu + adj < 576) { error = EINVAL; break; } ifp->if_mtu += adj; sc->key = key; break; case GREGKEY: error = copyout(&sc->key, ifr->ifr_data, sizeof(sc->key)); break; default: error = EINVAL; break; } 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; 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 * XXX MRT Use a different FIB for the tunnel to solve this problem. */ if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) { ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr ^= htonl(0x01); } #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_fib(ro, sc->gre_fibnum); /* * 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);