FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_gre.c

     /*      $NetBSD: ip_gre.c,v 1.44 2006/11/16 22:54:14 dyoung 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 <hwr@pilhuhn.de>
      *
     * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
     *
     * 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.
     */
    
    /*
     * deencapsulate tunneled packets and send them on
     * output half is in net/if_gre.[ch]
     * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: ip_gre.c,v 1.44 2006/11/16 22:54:14 dyoung Exp $");
    
    #include "gre.h"
    #if NGRE > 0
    
    #include "opt_inet.h"
    #include "opt_atalk.h"
    #include "bpfilter.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/mbuf.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/protosw.h>
    #include <sys/errno.h>
    #include <sys/time.h>
    #include <sys/kernel.h>
    #include <sys/ioctl.h>
    #include <sys/syslog.h>
    #include <net/bpf.h>
    #include <net/ethertypes.h>
    #include <net/if.h>
    #include <net/netisr.h>
    #include <net/route.h>
    #include <net/raw_cb.h>
    
    #ifdef INET
    #include <netinet/in.h>
    #include <netinet/in_var.h>
    #include <netinet/in_systm.h>
    #include <netinet/ip.h>
    #include <netinet/ip_var.h>
    #include <netinet/ip_gre.h>
    #else
    #error ip_gre input without IP?
    #endif
    
    
    #ifdef NETATALK
    #include <netatalk/at.h>
    #include <netatalk/at_var.h>
    #include <netatalk/at_extern.h>
    #endif
    
    /* Needs IP headers. */
    #include <net/if_gre.h>
    
    #include <machine/stdarg.h>
    
    #if 1
    void gre_inet_ntoa(struct in_addr in);  /* XXX */
   #endif
   
   struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
   
   int gre_input2(struct mbuf *, int, u_char);
   
   /*
    * De-encapsulate 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).
    * This really is simple
    */
   void
   gre_input(struct mbuf *m, ...)
   {
           int off, ret, proto;
           va_list ap;
   
           va_start(ap, m);
           off = va_arg(ap, int);
           proto = va_arg(ap, int);
           va_end(ap);
   
           ret = gre_input2(m, off, proto);
           /*
            * ret == 0 : packet not processed, meaning that
            * no matching tunnel that is up is found.
            * we inject it to raw ip socket to see if anyone picks it up.
            */
           if (ret == 0)
                   rip_input(m, off, proto);
   }
   
   /*
    * 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, u_char proto)
   {
           const struct greip *gip;
           struct gre_softc *sc;
   
           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, const struct greip *);
   
           return gre_input3(sc, m, hlen, proto, &gip->gi_g);
   }
   
   /*
    * input routine for IPPRPOTO_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
    */
   void
   gre_mobile_input(struct mbuf *m, ...)
   {
           struct ip *ip;
           struct mobip_h *mip;
           struct ifqueue *ifq;
           struct gre_softc *sc;
           uint8_t *hdr;
           int hlen, s;
           va_list ap;
           int msiz;
   
           va_start(ap, m);
           hlen = va_arg(ap, int);
           va_end(ap);
   
           if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
                   /* No matching tunnel or tunnel is down. */
                   m_freem(m);
                   return;
           }
   
           if (M_UNWRITABLE(m, sizeof(*mip))) {
                   m = m_pullup(m, sizeof(*mip));
                   if (m == NULL)
                           return;
           }
           ip = mtod(m, struct ip *);
           /* XXX what if there are IP options? */
           mip = mtod(m, struct mobip_h *);
   
           sc->sc_if.if_ipackets++;
           sc->sc_if.if_ibytes += m->m_pkthdr.len;
   
           if (ntohs(mip->mh.proto) & MOB_H_SBIT) {
                   msiz = MOB_H_SIZ_L;
                   mip->mi.ip_src.s_addr = mip->mh.osrc;
           } else
                   msiz = MOB_H_SIZ_S;
   
           if (M_UNWRITABLE(m, hlen + msiz)) {
                   m = m_pullup(m, hlen + msiz);
                   if (m == NULL)
                           return;
                   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_int16_t *)&mip->mh, msiz) != 0) {
                   m_freem(m);
                   return;
           }
   
           hdr = mtod(m, uint8_t *);
           memmove(hdr + hlen, hdr + hlen + msiz, m->m_len - msiz - hlen);
           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, hlen);
   
   #if NBPFILTER > 0
           if (sc->sc_if.if_bpf != NULL)
                   bpf_mtap_af(sc->sc_if.if_bpf, AF_INET, m);
   #endif /*NBPFILTER > 0*/
   
           ifq = &ipintrq;
           s = splnet();       /* possible */
           if (IF_QFULL(ifq)) {
                   IF_DROP(ifq);
                   m_freem(m);
           } else
                   IF_ENQUEUE(ifq, m);
           splx(s);
   }
   
   /*
    * Find the gre interface associated with our src/dst/proto set.
    */
   struct gre_softc *
   gre_lookup(struct mbuf *m, u_int8_t proto)
   {
           const struct ip *ip = mtod(m, const struct ip *);
           struct gre_softc *sc;
   
           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->sc_proto == proto &&
                       (sc->sc_if.if_flags & IFF_UP) != 0)
                           return sc;
           }
   
           return NULL;
   }
   
   #endif /* if NGRE > 0 */

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