/* $OpenBSD: ip_gre.c,v 1.68 2017/11/20 10:35:24 mpi Exp $ */ /* $NetBSD: ip_gre.c,v 1.9 1999/10/25 19:18:11 drochner 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. * * 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. */ /* * decapsulate tunneled packets and send them on * output half is in net/if_gre.[ch] * This currently handles IPPROTO_GRE, IPPROTO_MOBILE */ #include "gre.h" #if NGRE > 0 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef MPLS #include #endif #include "bpfilter.h" #include "pf.h" #if NPF > 0 #include #endif #ifdef PIPEX #include #endif /* Needs IP headers. */ #include struct gre_softc *gre_lookup(struct mbuf *, u_int8_t); int gre_input2(struct mbuf *, int, int); /* * Decapsulate. * Does the real work and is called from gre_input() (above) * returns 0 if packet is not yet processed * and 1 if it needs no further processing * proto is the protocol number of the "calling" foo_input() * routine. */ int gre_input2(struct mbuf *m, int hlen, int proto) { struct greip *gip; struct gre_softc *sc; u_short flags; u_int af; if ((sc = gre_lookup(m, proto)) == NULL) { /* No matching tunnel or tunnel is down. */ return (0); } if (m->m_len < sizeof(*gip)) { m = m_pullup(m, sizeof(*gip)); if (m == NULL) return (ENOBUFS); } gip = mtod(m, struct greip *); m->m_pkthdr.ph_ifidx = sc->sc_if.if_index; m->m_pkthdr.ph_rtableid = sc->sc_if.if_rdomain; sc->sc_if.if_ipackets++; sc->sc_if.if_ibytes += m->m_pkthdr.len; switch (proto) { case IPPROTO_GRE: hlen += sizeof (struct gre_h); /* process GRE flags as packet can be of variable len */ flags = ntohs(gip->gi_flags); /* Checksum & Offset are present */ if ((flags & GRE_CP) | (flags & GRE_RP)) hlen += 4; /* We don't support routing fields (variable length) */ if (flags & GRE_RP) return (0); if (flags & GRE_KP) hlen += 4; if (flags & GRE_SP) hlen += 4; switch (ntohs(gip->gi_ptype)) { /* ethertypes */ case GREPROTO_WCCP: /* WCCP/GRE: * So far as I can see (and test) it seems that Cisco's WCCP * GRE tunnel is precisely a IP-in-GRE tunnel that differs * only in its protocol number. At least, it works for me. * * The Internet Drafts can be found if you look for * the following: * draft-forster-wrec-wccp-v1-00.txt * draft-wilson-wrec-wccp-v2-01.txt * * So yes, we're doing a fall-through (unless, of course, * net.inet.gre.wccp is 0). */ if (!gre_wccp) return (0); /* * For WCCPv2, additionally skip the 4 byte * redirect header. */ if (gre_wccp == 2) hlen += 4; case ETHERTYPE_IP: af = AF_INET; break; #ifdef INET6 case ETHERTYPE_IPV6: af = AF_INET6; break; #endif case 0: /* keepalive reply, retrigger hold timer */ gre_recv_keepalive(sc); m_freem(m); return (1); #ifdef MPLS case ETHERTYPE_MPLS: case ETHERTYPE_MPLS_MCAST: mpls_input(m); return (1); #endif default: /* others not yet supported */ return (0); } break; default: /* others not yet supported */ return (0); } if (hlen > m->m_pkthdr.len) { m_freem(m); return (EINVAL); } m_adj(m, hlen); #if NBPFILTER > 0 if (sc->sc_if.if_bpf) bpf_mtap_af(sc->sc_if.if_bpf, af, m, BPF_DIRECTION_IN); #endif #if NPF > 0 pf_pkt_addr_changed(m); #endif switch (af) { case AF_INET: ipv4_input(&sc->sc_if, m); break; #ifdef INET6 case AF_INET6: ipv6_input(&sc->sc_if, m); break; #endif default: return (0); } return (1); /* packet is done, no further processing needed */ } /* * Decapsulate a packet and feed it back through ip_input (this * routine is called whenever IP gets a packet with proto type * IPPROTO_GRE and a local destination address). */ int gre_input(struct mbuf **mp, int *offp, int proto, int af) { struct mbuf *m = *mp; int hlen = *offp; int ret; if (!gre_allow) { m_freem(m); return IPPROTO_DONE; } #ifdef PIPEX if (pipex_enable) { struct pipex_session *session; if ((session = pipex_pptp_lookup_session(m)) != NULL) { if (pipex_pptp_input(m, session) == NULL) return IPPROTO_DONE; } } #endif ret = gre_input2(m, hlen, proto); /* * ret == 0: packet not processed, but input from here * means no matching tunnel that is up is found. * we inject it to raw ip socket to see if anyone picks it up. * possible that we received a WCCPv1-style GRE packet * but we're not set to accept them. */ if (!ret) return rip_input(mp, offp, proto, af); return IPPROTO_DONE; } /* * Input routine for IPPROTO_MOBILE. * This is a little bit different from the other modes, as the * encapsulating header was not prepended, but instead inserted * between IP header and payload. */ int gre_mobile_input(struct mbuf **mp, int *offp, int proto, int af) { struct mbuf *m = *mp; struct ip *ip; struct mobip_h *mip; struct gre_softc *sc; u_char osrc = 0; int msiz; if (!ip_mobile_allow) { m_freem(m); return IPPROTO_DONE; } if ((sc = gre_lookup(m, proto)) == NULL) { /* No matching tunnel or tunnel is down. */ m_freem(m); return IPPROTO_DONE; } if (m->m_len < sizeof(*mip)) { m = *mp = m_pullup(m, sizeof(*mip)); if (m == NULL) return IPPROTO_DONE; } ip = mtod(m, struct ip *); mip = mtod(m, struct mobip_h *); m->m_pkthdr.ph_ifidx = sc->sc_if.if_index; sc->sc_if.if_ipackets++; sc->sc_if.if_ibytes += m->m_pkthdr.len; if (ntohs(mip->mh.proto) & MOB_H_SBIT) { osrc = 1; msiz = MOB_H_SIZ_L; mip->mi.ip_src.s_addr = mip->mh.osrc; } else msiz = MOB_H_SIZ_S; if (m->m_len < (ip->ip_hl << 2) + msiz) { m = *mp = m_pullup(m, (ip->ip_hl << 2) + msiz); if (m == NULL) return IPPROTO_DONE; ip = mtod(m, struct ip *); mip = mtod(m, struct mobip_h *); } mip->mi.ip_dst.s_addr = mip->mh.odst; mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8); if (gre_in_cksum((u_short *) &mip->mh, msiz) != 0) { m_freem(m); return IPPROTO_DONE; } memmove(ip + (ip->ip_hl << 2), ip + (ip->ip_hl << 2) + msiz, m->m_len - msiz - (ip->ip_hl << 2)); m->m_len -= msiz; ip->ip_len = htons(ntohs(ip->ip_len) - msiz); m->m_pkthdr.len -= msiz; ip->ip_sum = 0; ip->ip_sum = in_cksum(m,(ip->ip_hl << 2)); #if NBPFILTER > 0 if (sc->sc_if.if_bpf) bpf_mtap_af(sc->sc_if.if_bpf, AF_INET, m, BPF_DIRECTION_IN); #endif #if NPF > 0 pf_pkt_addr_changed(m); #endif ipv4_input(&sc->sc_if, m); return IPPROTO_DONE; } /* * Find the gre interface associated with our src/dst/proto set. */ struct gre_softc * gre_lookup(struct mbuf *m, u_int8_t proto) { struct ip *ip = mtod(m, struct ip *); struct gre_softc *sc; NET_ASSERT_LOCKED(); LIST_FOREACH(sc, &gre_softc_list, sc_list) { if ((sc->g_dst.s_addr == ip->ip_src.s_addr) && (sc->g_src.s_addr == ip->ip_dst.s_addr) && (sc->g_proto == proto) && (rtable_l2(sc->g_rtableid) == rtable_l2(m->m_pkthdr.ph_rtableid)) && ((sc->sc_if.if_flags & IFF_UP) != 0)) return (sc); } return (NULL); } int gre_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { int error; /* All sysctl names at this level are terminal. */ if (namelen != 1) return (ENOTDIR); switch (name[0]) { case GRECTL_ALLOW: NET_LOCK(); error = sysctl_int(oldp, oldlenp, newp, newlen, &gre_allow); NET_UNLOCK(); return (error); case GRECTL_WCCP: NET_LOCK(); error = sysctl_int(oldp, oldlenp, newp, newlen, &gre_wccp); NET_UNLOCK(); return (error); default: return (ENOPROTOOPT); } /* NOTREACHED */ } int ipmobile_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { int error; /* All sysctl names at this level are terminal. */ if (namelen != 1) return (ENOTDIR); switch (name[0]) { case MOBILEIPCTL_ALLOW: NET_LOCK(); error = sysctl_int(oldp, oldlenp, newp, newlen, &ip_mobile_allow); NET_UNLOCK(); return (error); default: return (ENOPROTOOPT); } /* NOTREACHED */ } int gre_usrreq(struct socket *so, int req, struct mbuf *m, struct mbuf *nam, struct mbuf *control, struct proc *p) { #ifdef PIPEX struct inpcb *inp = sotoinpcb(so); if (inp != NULL && inp->inp_pipex && req == PRU_SEND) { struct sockaddr_in *sin4; struct in_addr *ina_dst; struct pipex_session *session; ina_dst = NULL; if ((so->so_state & SS_ISCONNECTED) != 0) { inp = sotoinpcb(so); if (inp) ina_dst = &inp->inp_laddr; } else if (nam) { if (in_nam2sin(nam, &sin4) == 0) ina_dst = &sin4->sin_addr; } if (ina_dst != NULL && (session = pipex_pptp_userland_lookup_session_ipv4(m, *ina_dst))) m = pipex_pptp_userland_output(m, session); if (m == NULL) return (ENOMEM); } #endif return rip_usrreq(so, req, m, nam, control, p); } #endif /* if NGRE > 0 */