616 lines
15 KiB
C
616 lines
15 KiB
C
/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */
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/*
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* Copyright (c) 1998 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Heiko W.Rupp <hwr@pilhuhn.de>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Encapsulate L3 protocols into IP
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* See RFC 1701 and 1702 for more details.
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* If_gre is compatible with Cisco GRE tunnels, so you can
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* have a NetBSD box as the other end of a tunnel interface of a Cisco
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* router. See gre(4) for more details.
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* Also supported: IP in IP encaps (proto 55) as of RFC 2004
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $");
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#include "opt_inet.h"
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#include "opt_ns.h"
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#include "bpfilter.h"
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#include <sys/param.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/proc.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <sys/queue.h>
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#if __NetBSD__
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#include <sys/systm.h>
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#endif
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#include <machine/cpu.h>
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#include <net/ethertypes.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/netisr.h>
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#include <net/route.h>
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#ifdef INET
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#else
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#error "Huh? if_gre without inet?"
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#endif
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#ifdef NS
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#include <netns/ns.h>
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#include <netns/ns_if.h>
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#endif
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#ifdef NETATALK
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#include <netatalk/at.h>
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#include <netatalk/at_var.h>
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#include <netatalk/at_extern.h>
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#endif
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#if NBPFILTER > 0
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#include <sys/time.h>
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#include <net/bpf.h>
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#endif
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#include <net/if_gre.h>
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/*
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* It is not easy to calculate the right value for a GRE MTU.
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* We leave this task to the admin and use the same default that
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* other vendors use.
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*/
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#define GREMTU 1476
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struct gre_softc_head gre_softc_list;
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int ip_gre_ttl = GRE_TTL;
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int gre_clone_create __P((struct if_clone *, int));
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void gre_clone_destroy __P((struct ifnet *));
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struct if_clone gre_cloner =
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IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy);
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int gre_compute_route(struct gre_softc *sc);
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void greattach __P((int));
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/* ARGSUSED */
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void
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greattach(count)
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int count;
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{
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LIST_INIT(&gre_softc_list);
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if_clone_attach(&gre_cloner);
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}
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int
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gre_clone_create(ifc, unit)
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struct if_clone *ifc;
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int unit;
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{
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struct gre_softc *sc;
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sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK);
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memset(sc, 0, sizeof(struct gre_softc));
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sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit);
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sc->sc_if.if_softc = sc;
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sc->sc_if.if_type = IFT_OTHER;
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sc->sc_if.if_addrlen = 0;
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sc->sc_if.if_hdrlen = 24; /* IP + GRE */
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sc->sc_if.if_dlt = DLT_NULL;
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sc->sc_if.if_mtu = GREMTU;
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sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
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sc->sc_if.if_output = gre_output;
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sc->sc_if.if_ioctl = gre_ioctl;
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sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
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sc->g_proto = IPPROTO_GRE;
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sc->sc_if.if_flags |= IFF_LINK0;
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if_attach(&sc->sc_if);
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if_alloc_sadl(&sc->sc_if);
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#if NBPFILTER > 0
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bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t));
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#endif
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LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
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return (0);
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}
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void
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gre_clone_destroy(ifp)
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struct ifnet *ifp;
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{
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struct gre_softc *sc = ifp->if_softc;
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LIST_REMOVE(sc, sc_list);
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#if NBPFILTER > 0
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bpfdetach(ifp);
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#endif
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if_detach(ifp);
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free(sc, M_DEVBUF);
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}
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/*
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* The output routine. Takes a packet and encapsulates it in the protocol
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* given by sc->g_proto. See also RFC 1701 and RFC 2004
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*/
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int
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gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
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struct rtentry *rt)
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{
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int error = 0;
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struct gre_softc *sc = ifp->if_softc;
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struct greip *gh;
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struct ip *ip;
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u_int16_t etype = 0;
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struct mobile_h mob_h;
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if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 ||
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sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
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m_freem(m);
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error = ENETDOWN;
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goto end;
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}
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gh = NULL;
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ip = NULL;
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#if NBPFILTER >0
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if (ifp->if_bpf) {
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/* see comment of other if_foo.c files */
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struct mbuf m0;
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u_int32_t af = dst->sa_family;
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m0.m_next = m;
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m0.m_len = 4;
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m0.m_data = (char *)⁡
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bpf_mtap(ifp->if_bpf, &m0);
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}
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#endif
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m->m_flags &= ~(M_BCAST|M_MCAST);
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if (sc->g_proto == IPPROTO_MOBILE) {
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if (dst->sa_family == AF_INET) {
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struct mbuf *m0;
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int msiz;
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ip = mtod(m, struct ip *);
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memset(&mob_h, 0, MOB_H_SIZ_L);
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mob_h.proto = (ip->ip_p) << 8;
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mob_h.odst = ip->ip_dst.s_addr;
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ip->ip_dst.s_addr = sc->g_dst.s_addr;
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/*
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* If the packet comes from our host, we only change
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* the destination address in the IP header.
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* Else we also need to save and change the source
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*/
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if (in_hosteq(ip->ip_src, sc->g_src)) {
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msiz = MOB_H_SIZ_S;
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} else {
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mob_h.proto |= MOB_H_SBIT;
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mob_h.osrc = ip->ip_src.s_addr;
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ip->ip_src.s_addr = sc->g_src.s_addr;
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msiz = MOB_H_SIZ_L;
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}
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HTONS(mob_h.proto);
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mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
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if ((m->m_data - msiz) < m->m_pktdat) {
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/* need new mbuf */
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MGETHDR(m0, M_DONTWAIT, MT_HEADER);
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if (m0 == NULL) {
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IF_DROP(&ifp->if_snd);
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m_freem(m);
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error = ENOBUFS;
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goto end;
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}
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m0->m_next = m;
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m->m_data += sizeof(struct ip);
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m->m_len -= sizeof(struct ip);
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m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
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m0->m_len = msiz + sizeof(struct ip);
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m0->m_data += max_linkhdr;
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memcpy(mtod(m0, caddr_t), (caddr_t)ip,
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sizeof(struct ip));
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m = m0;
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} else { /* we have some space left in the old one */
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m->m_data -= msiz;
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m->m_len += msiz;
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m->m_pkthdr.len += msiz;
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memmove(mtod(m, caddr_t), ip,
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sizeof(struct ip));
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}
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ip = mtod(m, struct ip *);
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memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
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ip->ip_len = htons(ntohs(ip->ip_len) + msiz);
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} else { /* AF_INET */
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IF_DROP(&ifp->if_snd);
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m_freem(m);
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error = EINVAL;
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goto end;
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}
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} else if (sc->g_proto == IPPROTO_GRE) {
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switch (dst->sa_family) {
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case AF_INET:
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ip = mtod(m, struct ip *);
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etype = ETHERTYPE_IP;
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break;
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#ifdef NETATALK
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case AF_APPLETALK:
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etype = ETHERTYPE_ATALK;
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break;
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#endif
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#ifdef NS
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case AF_NS:
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etype = ETHERTYPE_NS;
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break;
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#endif
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default:
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IF_DROP(&ifp->if_snd);
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m_freem(m);
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error = EAFNOSUPPORT;
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goto end;
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}
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M_PREPEND(m, sizeof(struct greip), M_DONTWAIT);
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} else {
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IF_DROP(&ifp->if_snd);
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m_freem(m);
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error = EINVAL;
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goto end;
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}
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if (m == NULL) { /* impossible */
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IF_DROP(&ifp->if_snd);
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error = ENOBUFS;
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goto end;
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}
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gh = mtod(m, struct greip *);
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if (sc->g_proto == IPPROTO_GRE) {
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/* we don't have any GRE flags for now */
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memset((void *)&gh->gi_g, 0, sizeof(struct gre_h));
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gh->gi_ptype = htons(etype);
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}
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gh->gi_pr = sc->g_proto;
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if (sc->g_proto != IPPROTO_MOBILE) {
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gh->gi_src = sc->g_src;
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gh->gi_dst = sc->g_dst;
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((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
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((struct ip*)gh)->ip_ttl = ip_gre_ttl;
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((struct ip*)gh)->ip_tos = ip->ip_tos;
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gh->gi_len = htons(m->m_pkthdr.len);
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}
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ifp->if_opackets++;
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ifp->if_obytes += m->m_pkthdr.len;
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/* send it off */
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error = ip_output(m, NULL, &sc->route, 0,
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(struct ip_moptions *)NULL, (struct socket *)NULL);
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end:
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if (error)
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ifp->if_oerrors++;
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return (error);
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}
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int
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gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
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{
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struct proc *p = curproc; /* XXX */
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struct ifreq *ifr = (struct ifreq *)data;
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struct if_laddrreq *lifr = (struct if_laddrreq *)data;
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struct gre_softc *sc = ifp->if_softc;
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int s;
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struct sockaddr_in si;
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struct sockaddr *sa = NULL;
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int error;
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error = 0;
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s = splnet();
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switch (cmd) {
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case SIOCSIFADDR:
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ifp->if_flags |= IFF_UP;
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break;
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case SIOCSIFDSTADDR:
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break;
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case SIOCSIFFLAGS:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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if ((ifr->ifr_flags & IFF_LINK0) != 0)
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sc->g_proto = IPPROTO_GRE;
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else
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sc->g_proto = IPPROTO_MOBILE;
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break;
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case SIOCSIFMTU:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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if (ifr->ifr_mtu < 576) {
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error = EINVAL;
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break;
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}
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ifp->if_mtu = ifr->ifr_mtu;
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break;
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case SIOCGIFMTU:
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ifr->ifr_mtu = sc->sc_if.if_mtu;
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break;
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case SIOCADDMULTI:
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case SIOCDELMULTI:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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if (ifr == 0) {
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error = EAFNOSUPPORT;
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break;
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}
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switch (ifr->ifr_addr.sa_family) {
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#ifdef INET
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case AF_INET:
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break;
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#endif
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default:
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error = EAFNOSUPPORT;
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break;
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}
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break;
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case GRESPROTO:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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sc->g_proto = ifr->ifr_flags;
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switch (sc->g_proto) {
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case IPPROTO_GRE:
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ifp->if_flags |= IFF_LINK0;
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break;
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case IPPROTO_MOBILE:
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ifp->if_flags &= ~IFF_LINK0;
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break;
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default:
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error = EPROTONOSUPPORT;
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break;
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}
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break;
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case GREGPROTO:
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ifr->ifr_flags = sc->g_proto;
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break;
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case GRESADDRS:
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case GRESADDRD:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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/*
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* set tunnel endpoints, compute a less specific route
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* to the remote end and mark if as up
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*/
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sa = &ifr->ifr_addr;
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if (cmd == GRESADDRS)
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sc->g_src = (satosin(sa))->sin_addr;
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if (cmd == GRESADDRD)
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sc->g_dst = (satosin(sa))->sin_addr;
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recompute:
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if ((sc->g_src.s_addr != INADDR_ANY) &&
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(sc->g_dst.s_addr != INADDR_ANY)) {
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if (sc->route.ro_rt != 0) /* free old route */
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RTFREE(sc->route.ro_rt);
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if (gre_compute_route(sc) == 0)
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ifp->if_flags |= IFF_RUNNING;
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else
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ifp->if_flags &= ~IFF_RUNNING;
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}
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break;
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case GREGADDRS:
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memset(&si, 0, sizeof(si));
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si.sin_family = AF_INET;
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si.sin_len = sizeof(struct sockaddr_in);
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si.sin_addr.s_addr = sc->g_src.s_addr;
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sa = sintosa(&si);
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ifr->ifr_addr = *sa;
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break;
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case GREGADDRD:
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memset(&si, 0, sizeof(si));
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si.sin_family = AF_INET;
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si.sin_len = sizeof(struct sockaddr_in);
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si.sin_addr.s_addr = sc->g_dst.s_addr;
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sa = sintosa(&si);
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ifr->ifr_addr = *sa;
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break;
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case SIOCSLIFPHYADDR:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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if (lifr->addr.ss_family != AF_INET ||
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lifr->dstaddr.ss_family != AF_INET) {
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error = EAFNOSUPPORT;
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break;
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}
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if (lifr->addr.ss_len != sizeof(si) ||
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lifr->dstaddr.ss_len != sizeof(si)) {
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error = EINVAL;
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break;
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}
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sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr;
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sc->g_dst =
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(satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr;
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goto recompute;
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case SIOCDIFPHYADDR:
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if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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break;
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sc->g_src.s_addr = INADDR_ANY;
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sc->g_dst.s_addr = INADDR_ANY;
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break;
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case SIOCGLIFPHYADDR:
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if (sc->g_src.s_addr == INADDR_ANY ||
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sc->g_dst.s_addr == INADDR_ANY) {
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error = EADDRNOTAVAIL;
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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);
|
|
}
|