ip_gre.c

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    1 /*
    2  * $NetBSD: ip_gre.c,v 1.21 2002/08/14 00:23:30 itojun Exp $
    3  *
    4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
    5  * All rights reserved.
    6  *
    7  * This code is derived from software contributed to The NetBSD Foundation
    8  * by Heiko W.Rupp <hwr@pilhuhn.de>
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *        This product includes software developed by the NetBSD
   21  *        Foundation, Inc. and its contributors.
   22  * 4. Neither the name of The NetBSD Foundation nor the names of its
   23  *    contributors may be used to endorse or promote products derived
   24  *    from this software without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   36  * POSSIBILITY OF SUCH DAMAGE.
   37  */
   38 
   39 /*
   40  * deencapsulate tunneled packets and send them on
   41  * output half is in net/if_gre.[ch]
   42  * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
   43  */
   44 
   45 #include "opt_inet.h"
   46 
   47 #include <sys/param.h>
   48 #include <sys/systm.h>
   49 #include <sys/mbuf.h>
   50 #include <sys/socket.h>
   51 #include <sys/socketvar.h>
   52 #include <sys/protosw.h>
   53 #include <sys/errno.h>
   54 #include <sys/time.h>
   55 #include <sys/kernel.h>
   56 #include <sys/syslog.h>
   57 #include <sys/in_cksum.h>
   58 #include <net/bpf.h>
   59 #include <net/ethernet.h>
   60 #include <net/if.h>
   61 #include <net/netisr.h>
   62 #include <net/route.h>
   63 #include <net/raw_cb.h>
   64 
   65 #ifdef INET
   66 #include <netinet/in.h>
   67 #include <netinet/in_var.h>
   68 #include <netinet/in_systm.h>
   69 #include <netinet/ip.h>
   70 #include <netinet/ip_var.h>
   71 #include <netinet/ip_gre.h>
   72 #else
   73 #error ip_gre input without IP?
   74 #endif
   75 
   76 /* Needs IP headers. */
   77 #include <net/gre/if_gre.h>
   78 
   79 #include <machine/stdarg.h>
   80 
   81 #if 1
   82 void gre_inet_ntoa(struct in_addr in);  /* XXX */
   83 #endif
   84 
   85 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
   86 
   87 static int      gre_input2(struct mbuf *, int, u_char);
   88 
   89 /*
   90  * De-encapsulate a packet and feed it back through ip input (this
   91  * routine is called whenever IP gets a packet with proto type
   92  * IPPROTO_GRE and a local destination address).
   93  * This really is simple
   94  */
   95 int
   96 gre_input(struct mbuf **mp, int *offp, int proto)
   97 {
   98         struct mbuf *m;
   99         int ret, off;
  100 
  101         off = *offp;
  102         m = *mp;
  103         *mp = NULL;
  104 
  105         proto = (mtod(m, struct ip *))->ip_p;
  106 
  107         ret = gre_input2(m, off, proto);
  108         /*
  109          * ret == 0 : packet not processed, meaning that
  110          * no matching tunnel that is up is found.
  111          * we inject it to raw ip socket to see if anyone picks it up.
  112          */
  113         if (ret == 0) {
  114                 *mp = m;
  115                 rip_input(mp, offp, proto);
  116         }
  117         return(IPPROTO_DONE);
  118 }
  119 
  120 /*
  121  * decapsulate.
  122  * Does the real work and is called from gre_input() (above)
  123  * returns 0 if packet is not yet processed
  124  * and 1 if it needs no further processing
  125  * proto is the protocol number of the "calling" foo_input()
  126  * routine.
  127  */
  128 
  129 static int
  130 gre_input2(struct mbuf *m ,int hlen, u_char proto)
  131 {
  132         static const uint32_t af = AF_INET;
  133         struct greip *gip = mtod(m, struct greip *);
  134         int isr;
  135         struct gre_softc *sc;
  136         u_short flags;
  137 
  138         if ((sc = gre_lookup(m, proto)) == NULL) {
  139                 /* No matching tunnel or tunnel is down. */
  140                 return (0);
  141         }
  142 
  143         IFNET_STAT_INC(&sc->sc_if, ipackets, 1);
  144         IFNET_STAT_INC(&sc->sc_if, ibytes, m->m_pkthdr.len);
  145 
  146         switch (proto) {
  147         case IPPROTO_GRE:
  148                 hlen += sizeof (struct gre_h);
  149 
  150                 /* process GRE flags as packet can be of variable len */
  151                 flags = ntohs(gip->gi_flags);
  152 
  153                 /* Checksum & Offset are present */
  154                 if ((flags & GRE_CP) | (flags & GRE_RP))
  155                         hlen += 4;
  156                 /* We don't support routing fields (variable length) */
  157                 if (flags & GRE_RP)
  158                         return(0);
  159                 if (flags & GRE_KP)
  160                         hlen += 4;
  161                 if (flags & GRE_SP)
  162                         hlen +=4;
  163 
  164                 switch (ntohs(gip->gi_ptype)) { /* ethertypes */
  165                 case ETHERTYPE_IP:
  166                 case WCCP_PROTOCOL_TYPE:
  167                         isr = NETISR_IP;
  168                         break;
  169                 case ETHERTYPE_IPV6:
  170                         /* FALLTHROUGH */
  171                 default:           /* others not yet supported */
  172                         return(0);
  173                 }
  174                 break;
  175         default:
  176                 /* others not yet supported */
  177                 return(0);
  178         }
  179 
  180         m->m_data += hlen;
  181         m->m_len -= hlen;
  182         m->m_pkthdr.len -= hlen;
  183 
  184         if (sc->sc_if.if_bpf) {
  185                 bpf_gettoken();
  186                 if (sc->sc_if.if_bpf)
  187                         bpf_ptap(sc->sc_if.if_bpf, m, &af, sizeof(af));
  188                 bpf_reltoken();
  189         }
  190 
  191         m->m_pkthdr.rcvif = &sc->sc_if;
  192         netisr_queue(isr, m);
  193         return(1);      /* packet is done, no further processing needed */
  194 }
  195 
  196 /*
  197  * input routine for IPPRPOTO_MOBILE
  198  * This is a little bit diffrent from the other modes, as the
  199  * encapsulating header was not prepended, but instead inserted
  200  * between IP header and payload
  201  */
  202 
  203 int
  204 gre_mobile_input(struct mbuf **mp, int *offp, int proto)
  205 {
  206         static const uint32_t af = AF_INET;
  207         struct mbuf *m = *mp;
  208         struct ip *ip = mtod(m, struct ip *);
  209         struct mobip_h *mip = mtod(m, struct mobip_h *);
  210         struct gre_softc *sc;
  211         int msiz;
  212 
  213         if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
  214                 /* No matching tunnel or tunnel is down. */
  215                 m_freem(m);
  216                 return(IPPROTO_DONE);
  217         }
  218 
  219         IFNET_STAT_INC(&sc->sc_if, ipackets, 1);
  220         IFNET_STAT_INC(&sc->sc_if, ibytes, m->m_pkthdr.len);
  221 
  222         if(ntohs(mip->mh.proto) & MOB_H_SBIT) {
  223                 msiz = MOB_H_SIZ_L;
  224                 mip->mi.ip_src.s_addr = mip->mh.osrc;
  225         } else {
  226                 msiz = MOB_H_SIZ_S;
  227         }
  228         mip->mi.ip_dst.s_addr = mip->mh.odst;
  229         mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8);
  230 
  231         if (gre_in_cksum((u_short*)&mip->mh,msiz) != 0) {
  232                 m_freem(m);
  233                 return(IPPROTO_DONE);
  234         }
  235 
  236         bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) +
  237             (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2));
  238         m->m_len -= msiz;
  239         m->m_pkthdr.len -= msiz;
  240 
  241         /*
  242          * On FreeBSD, rip_input() supplies us with ip->ip_len
  243          * already converted into host byteorder and also decreases
  244          * it by the lengh of IP header, however, ip_input() expects
  245          * that this field is in the original format (network byteorder
  246          * and full size of IP packet), so that adjust accordingly.
  247          */
  248         ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz);
  249         
  250         ip->ip_sum = 0;
  251         ip->ip_sum = in_cksum(m, (ip->ip_hl << 2));
  252 
  253         if (sc->sc_if.if_bpf) {
  254                 bpf_gettoken();
  255                 if (sc->sc_if.if_bpf)
  256                         bpf_ptap(sc->sc_if.if_bpf, m, &af, sizeof(af));
  257                 bpf_reltoken();
  258         }
  259 
  260         m->m_pkthdr.rcvif = &sc->sc_if;
  261 
  262         netisr_queue(NETISR_IP, m);
  263         return(IPPROTO_DONE);
  264 }
  265 
  266 /*
  267  * Find the gre interface associated with our src/dst/proto set.
  268  */
  269 static struct gre_softc *
  270 gre_lookup(struct mbuf *m, u_int8_t proto)
  271 {
  272         struct ip *ip = mtod(m, struct ip *);
  273         struct gre_softc *sc;
  274 
  275         for (sc = LIST_FIRST(&gre_softc_list); sc != NULL;
  276              sc = LIST_NEXT(sc, sc_list)) {
  277                 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
  278                     (sc->g_src.s_addr == ip->ip_dst.s_addr) &&
  279                     (sc->g_proto == proto) &&
  280                     ((sc->sc_if.if_flags & IFF_UP) != 0))
  281                         return (sc);
  282         }
  283 
  284         return (NULL);
  285 }
Cache object: 247e8366fa6885e4dc0996e936a4867e
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FreeBSD/Linux Kernel Cross Reference sys/netinet/ip_gre.c

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