sys/netinet/ip_gre.c

   1 /*
   2  * $NetBSD: ip_gre.c,v 1.21 2002/08/14 00:23:30 itojun Exp $
   3  * $DragonFly: src/sys/netinet/ip_gre.c,v 1.10 2006/01/14 11:33:50 swildner Exp $
   4  *
   5  * Copyright (c) 1998 The NetBSD Foundation, Inc.
   6  * All rights reserved.
   7  *
   8  * This code is derived from software contributed to The NetBSD Foundation
   9  * by Heiko W.Rupp <hwr@pilhuhn.de>
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *        This product includes software developed by the NetBSD
  22  *        Foundation, Inc. and its contributors.
  23  * 4. Neither the name of The NetBSD Foundation nor the names of its
  24  *    contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  37  * POSSIBILITY OF SUCH DAMAGE.
  38  */
  39
  40 /*
  41  * deencapsulate tunneled packets and send them on
  42  * output half is in net/if_gre.[ch]
  43  * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
  44  */
  45
  46 #include "opt_inet.h"
  47 #include "opt_ns.h"
  48 #include "opt_atalk.h"
  49
  50 #include <sys/param.h>
  51 #include <sys/systm.h>
  52 #include <sys/mbuf.h>
  53 #include <sys/socket.h>
  54 #include <sys/socketvar.h>
  55 #include <sys/protosw.h>
  56 #include <sys/errno.h>
  57 #include <sys/time.h>
  58 #include <sys/kernel.h>
  59 #include <sys/syslog.h>
  60 #include <sys/in_cksum.h>
  61 #include <net/bpf.h>
  62 #include <net/ethernet.h>
  63 #include <net/if.h>
  64 #include <net/netisr.h>
  65 #include <net/route.h>
  66 #include <net/raw_cb.h>
  67
  68 #ifdef INET
  69 #include <netinet/in.h>
  70 #include <netinet/in_var.h>
  71 #include <netinet/in_systm.h>
  72 #include <netinet/ip.h>
  73 #include <netinet/ip_var.h>
  74 #include <netinet/ip_gre.h>
  75 #else
  76 #error ip_gre input without IP?
  77 #endif
  78
  79 #ifdef NS
  80 #include <netproto/ns/ns.h>
  81 #include <netproto/ns/ns_if.h>
  82 #endif
  83
  84 #ifdef NETATALK
  85 #include <netproto/atalk/at.h>
  86 #include <netproto/atalk/at_var.h>
  87 #include <netproto/atalk/at_extern.h>
  88 #endif
  89
  90 /* Needs IP headers. */
  91 #include <net/gre/if_gre.h>
  92
  93 #include <machine/stdarg.h>
  94
  95 #if 1
  96 void gre_inet_ntoa(struct in_addr in);  /* XXX */
  97 #endif
  98
  99 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
 100
 101 static int      gre_input2(struct mbuf *, int, u_char);
 102
 103 /*
 104  * De-encapsulate a packet and feed it back through ip input (this
 105  * routine is called whenever IP gets a packet with proto type
 106  * IPPROTO_GRE and a local destination address).
 107  * This really is simple
 108  */
 109 void
 110 gre_input(struct mbuf *m, ...)
 111 {
 112         int ret, off, proto;
 113         __va_list ap;
 114
 115         __va_start(ap, m);
 116         off = __va_arg(ap, int);
 117         __va_end(ap);
 118
 119         proto = (mtod(m, struct ip *))->ip_p;
 120
 121         ret = gre_input2(m, off, proto);
 122         /*
 123          * ret == 0 : packet not processed, meaning that
 124          * no matching tunnel that is up is found.
 125          * we inject it to raw ip socket to see if anyone picks it up.
 126          */
 127         if (ret == 0)
 128                 rip_input(m, off, proto);
 129 }
 130
 131 /*
 132  * decapsulate.
 133  * Does the real work and is called from gre_input() (above)
 134  * returns 0 if packet is not yet processed
 135  * and 1 if it needs no further processing
 136  * proto is the protocol number of the "calling" foo_input()
 137  * routine.
 138  */
 139
 140 static int
 141 gre_input2(struct mbuf *m ,int hlen, u_char proto)
 142 {
 143         static const uint32_t af = AF_INET;
 144         struct greip *gip = mtod(m, struct greip *);
 145         int isr;
 146         struct gre_softc *sc;
 147         u_short flags;
 148
 149         if ((sc = gre_lookup(m, proto)) == NULL) {
 150                 /* No matching tunnel or tunnel is down. */
 151                 return (0);
 152         }
 153
 154         sc->sc_if.if_ipackets++;
 155         sc->sc_if.if_ibytes += m->m_pkthdr.len;
 156
 157         switch (proto) {
 158         case IPPROTO_GRE:
 159                 hlen += sizeof (struct gre_h);
 160
 161                 /* process GRE flags as packet can be of variable len */
 162                 flags = ntohs(gip->gi_flags);
 163
 164                 /* Checksum & Offset are present */
 165                 if ((flags & GRE_CP) | (flags & GRE_RP))
 166                         hlen += 4;
 167                 /* We don't support routing fields (variable length) */
 168                 if (flags & GRE_RP)
 169                         return(0);
 170                 if (flags & GRE_KP)
 171                         hlen += 4;
 172                 if (flags & GRE_SP)
 173                         hlen +=4;
 174
 175                 switch (ntohs(gip->gi_ptype)) { /* ethertypes */
 176                 case ETHERTYPE_IP:
 177                 case WCCP_PROTOCOL_TYPE:
 178                         isr = NETISR_IP;
 179                         break;
 180 #ifdef NS
 181                 case ETHERTYPE_NS:
 182                         isr = NETISR_NS;
 183                         break;
 184 #endif
 185 #ifdef NETATALK
 186                 case ETHERTYPE_ATALK:
 187                         isr = NETISR_ATALK1;
 188                         break;
 189 #endif
 190                 case ETHERTYPE_IPV6:
 191                         /* FALLTHROUGH */
 192                 default:           /* others not yet supported */
 193                         return(0);
 194                 }
 195                 break;
 196         default:
 197                 /* others not yet supported */
 198                 return(0);
 199         }
 200
 201         m->m_data += hlen;
 202         m->m_len -= hlen;
 203         m->m_pkthdr.len -= hlen;
 204
 205         if (sc->sc_if.if_bpf)
 206                 bpf_ptap(sc->sc_if.if_bpf, m, &af, sizeof(af));
 207
 208         m->m_pkthdr.rcvif = &sc->sc_if;
 209         netisr_dispatch(isr, m);
 210         return(1);      /* packet is done, no further processing needed */
 211 }
 212
 213 /*
 214  * input routine for IPPRPOTO_MOBILE
 215  * This is a little bit diffrent from the other modes, as the
 216  * encapsulating header was not prepended, but instead inserted
 217  * between IP header and payload
 218  */
 219
 220 void
 221 gre_mobile_input(struct mbuf *m, ...)
 222 {
 223         static const uint32_t af = AF_INET;
 224         struct ip *ip = mtod(m, struct ip *);
 225         struct mobip_h *mip = mtod(m, struct mobip_h *);
 226         struct gre_softc *sc;
 227         u_char osrc = 0;
 228         int msiz, hlen;
 229         __va_list ap;
 230
 231         __va_start(ap, m);
 232         hlen = __va_arg(ap, int);
 233         __va_end(ap);
 234
 235         if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
 236                 /* No matching tunnel or tunnel is down. */
 237                 m_freem(m);
 238                 return;
 239         }
 240
 241         sc->sc_if.if_ipackets++;
 242         sc->sc_if.if_ibytes += m->m_pkthdr.len;
 243
 244         if(ntohs(mip->mh.proto) & MOB_H_SBIT) {
 245                 osrc = 1;
 246                 msiz = MOB_H_SIZ_L;
 247                 mip->mi.ip_src.s_addr = mip->mh.osrc;
 248         } else {
 249                 msiz = MOB_H_SIZ_S;
 250         }
 251         mip->mi.ip_dst.s_addr = mip->mh.odst;
 252         mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8);
 253
 254         if (gre_in_cksum((u_short*)&mip->mh,msiz) != 0) {
 255                 m_freem(m);
 256                 return;
 257         }
 258
 259         bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) +
 260             (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2));
 261         m->m_len -= msiz;
 262         m->m_pkthdr.len -= msiz;
 263
 264         /*
 265          * On FreeBSD, rip_input() supplies us with ip->ip_len
 266          * already converted into host byteorder and also decreases
 267          * it by the lengh of IP header, however, ip_input() expects
 268          * that this field is in the original format (network byteorder
 269          * and full size of IP packet), so that adjust accordingly.
 270          */
 271         ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz);
 272
 273         ip->ip_sum = 0;
 274         ip->ip_sum = in_cksum(m, (ip->ip_hl << 2));
 275
 276         if (sc->sc_if.if_bpf)
 277                 bpf_ptap(sc->sc_if.if_bpf, m, &af, sizeof(af));
 278
 279         m->m_pkthdr.rcvif = &sc->sc_if;
 280
 281         netisr_dispatch(NETISR_IP, m);
 282 }
 283
 284 /*
 285  * Find the gre interface associated with our src/dst/proto set.
 286  */
 287 static struct gre_softc *
 288 gre_lookup(struct mbuf *m, u_int8_t proto)
 289 {
 290         struct ip *ip = mtod(m, struct ip *);
 291         struct gre_softc *sc;
 292
 293         for (sc = LIST_FIRST(&gre_softc_list); sc != NULL;
 294              sc = LIST_NEXT(sc, sc_list)) {
 295                 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
 296                     (sc->g_src.s_addr == ip->ip_dst.s_addr) &&
 297                     (sc->g_proto == proto) &&
 298                     ((sc->sc_if.if_flags & IFF_UP) != 0))
 299                         return (sc);
 300         }
 301
 302         return (NULL);
 303 }