ip_gre.c

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    1 /*      $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $ */
    2 /*       $FreeBSD: releng/6.0/sys/netinet/ip_gre.c 148943 2005-08-10 19:12:32Z bz $ */
    3 
    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  * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 3. All advertising materials mentioning features or use of this software
   22  *    must display the following acknowledgement:
   23  *        This product includes software developed by the NetBSD
   24  *        Foundation, Inc. and its contributors.
   25  * 4. Neither the name of The NetBSD Foundation nor the names of its
   26  *    contributors may be used to endorse or promote products derived
   27  *    from this software without specific prior written permission.
   28  *
   29  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   30  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   31  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   32  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   33  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   34  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   35  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   36  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   37  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   39  * POSSIBILITY OF SUCH DAMAGE.
   40  */
   41 
   42 /*
   43  * deencapsulate tunneled packets and send them on
   44  * output half is in net/if_gre.[ch]
   45  * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
   46  */
   47 
   48 #include "opt_inet.h"
   49 #include "opt_atalk.h"
   50 #include "opt_inet6.h"
   51 
   52 #include <sys/param.h>
   53 #include <sys/systm.h>
   54 #include <sys/mbuf.h>
   55 #include <sys/socket.h>
   56 #include <sys/socketvar.h>
   57 #include <sys/protosw.h>
   58 #include <sys/errno.h>
   59 #include <sys/time.h>
   60 #include <sys/kernel.h>
   61 #include <sys/syslog.h>
   62 #include <net/bpf.h>
   63 #include <net/ethernet.h>
   64 #include <net/if.h>
   65 #include <net/netisr.h>
   66 #include <net/route.h>
   67 #include <net/raw_cb.h>
   68 
   69 #ifdef INET
   70 #include <netinet/in.h>
   71 #include <netinet/in_var.h>
   72 #include <netinet/in_systm.h>
   73 #include <netinet/ip.h>
   74 #include <netinet/ip_var.h>
   75 #include <netinet/ip_gre.h>
   76 #include <machine/in_cksum.h>
   77 #else
   78 #error ip_gre input without IP?
   79 #endif
   80 
   81 #ifdef NETATALK
   82 #include <netatalk/at.h>
   83 #include <netatalk/at_var.h>
   84 #include <netatalk/at_extern.h>
   85 #endif
   86 
   87 /* Needs IP headers. */
   88 #include <net/if_gre.h>
   89 
   90 #include <machine/stdarg.h>
   91 
   92 #if 1
   93 void gre_inet_ntoa(struct in_addr in);  /* XXX */
   94 #endif
   95 
   96 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
   97 
   98 static int      gre_input2(struct mbuf *, int, u_char);
   99 
  100 /*
  101  * De-encapsulate a packet and feed it back through ip input (this
  102  * routine is called whenever IP gets a packet with proto type
  103  * IPPROTO_GRE and a local destination address).
  104  * This really is simple
  105  */
  106 void
  107 #if __STDC__
  108 gre_input(struct mbuf *m, ...)
  109 #else
  110 gre_input(m, va_alist)
  111         struct mbuf *m;
  112         va_dcl
  113 #endif
  114 {
  115         int off, ret, proto;
  116         va_list ap;
  117 
  118         va_start(ap, m);
  119         off = va_arg(ap, int);
  120         va_end(ap);
  121         proto = (mtod(m, struct ip *))->ip_p;
  122 
  123         ret = gre_input2(m, off, proto);
  124         /*
  125          * ret == 0 : packet not processed, meaning that
  126          * no matching tunnel that is up is found.
  127          * we inject it to raw ip socket to see if anyone picks it up.
  128          */
  129         if (ret == 0)
  130                 rip_input(m, off);
  131 }
  132 
  133 /*
  134  * decapsulate.
  135  * Does the real work and is called from gre_input() (above)
  136  * returns 0 if packet is not yet processed
  137  * and 1 if it needs no further processing
  138  * proto is the protocol number of the "calling" foo_input()
  139  * routine.
  140  */
  141 static int
  142 gre_input2(struct mbuf *m ,int hlen, u_char proto)
  143 {
  144         struct greip *gip;
  145         int isr;
  146         struct gre_softc *sc;
  147         u_int16_t flags;
  148         u_int32_t af;
  149 
  150         if ((sc = gre_lookup(m, proto)) == NULL) {
  151                 /* No matching tunnel or tunnel is down. */
  152                 return (0);
  153         }
  154 
  155         if (m->m_len < sizeof(*gip)) {
  156                 m = m_pullup(m, sizeof(*gip));
  157                 if (m == NULL)
  158                         return (ENOBUFS);
  159         }
  160         gip = mtod(m, struct greip *);
  161 
  162         GRE2IFP(sc)->if_ipackets++;
  163         GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len;
  164 
  165         switch (proto) {
  166         case IPPROTO_GRE:
  167                 hlen += sizeof(struct gre_h);
  168 
  169                 /* process GRE flags as packet can be of variable len */
  170                 flags = ntohs(gip->gi_flags);
  171 
  172                 /* Checksum & Offset are present */
  173                 if ((flags & GRE_CP) | (flags & GRE_RP))
  174                         hlen += 4;
  175                 /* We don't support routing fields (variable length) */
  176                 if (flags & GRE_RP)
  177                         return (0);
  178                 if (flags & GRE_KP)
  179                         hlen += 4;
  180                 if (flags & GRE_SP)
  181                         hlen += 4;
  182 
  183                 switch (ntohs(gip->gi_ptype)) { /* ethertypes */
  184                 case WCCP_PROTOCOL_TYPE:
  185                         if (sc->wccp_ver == WCCP_V2)
  186                                 hlen += 4;
  187                         /* FALLTHROUGH */
  188                 case ETHERTYPE_IP:      /* shouldn't need a schednetisr(), */
  189                         isr = NETISR_IP;/* as we are in ip_input */
  190                         af = AF_INET;
  191                         break;
  192 #ifdef INET6
  193                 case ETHERTYPE_IPV6:
  194                         isr = NETISR_IPV6;
  195                         af = AF_INET6;
  196                         break;
  197 #endif
  198 #ifdef NETATALK
  199                 case ETHERTYPE_ATALK:
  200                         isr = NETISR_ATALK1;
  201                         af = AF_APPLETALK;
  202                         break;
  203 #endif
  204                 default:           /* others not yet supported */
  205                         return (0);
  206                 }
  207                 break;
  208         default:
  209                 /* others not yet supported */
  210                 return (0);
  211         }
  212 
  213         if (hlen > m->m_pkthdr.len) {
  214                 m_freem(m);
  215                 return (EINVAL);
  216         }
  217         /* Unlike NetBSD, in FreeBSD m_adj() adjusts m->m_pkthdr.len as well */
  218         m_adj(m, hlen);
  219 
  220         if (GRE2IFP(sc)->if_bpf) {
  221                 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m);
  222         }
  223 
  224         m->m_pkthdr.rcvif = GRE2IFP(sc);
  225 
  226         netisr_dispatch(isr, m);
  227 
  228         return (1);     /* packet is done, no further processing needed */
  229 }
  230 
  231 /*
  232  * input routine for IPPRPOTO_MOBILE
  233  * This is a little bit diffrent from the other modes, as the
  234  * encapsulating header was not prepended, but instead inserted
  235  * between IP header and payload
  236  */
  237 
  238 void
  239 #if __STDC__
  240 gre_mobile_input(struct mbuf *m, ...)
  241 #else
  242 gre_mobile_input(m, va_alist)
  243         struct mbuf *m;
  244         va_dcl
  245 #endif
  246 {
  247         struct ip *ip;
  248         struct mobip_h *mip;
  249         struct gre_softc *sc;
  250         int hlen;
  251         va_list ap;
  252         int msiz;
  253 
  254         va_start(ap, m);
  255         hlen = va_arg(ap, int);
  256         va_end(ap);
  257 
  258         if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
  259                 /* No matching tunnel or tunnel is down. */
  260                 m_freem(m);
  261                 return;
  262         }
  263 
  264         if (m->m_len < sizeof(*mip)) {
  265                 m = m_pullup(m, sizeof(*mip));
  266                 if (m == NULL)
  267                         return;
  268         }
  269         ip = mtod(m, struct ip *);
  270         mip = mtod(m, struct mobip_h *);
  271 
  272         GRE2IFP(sc)->if_ipackets++;
  273         GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len;
  274 
  275         if (ntohs(mip->mh.proto) & MOB_H_SBIT) {
  276                 msiz = MOB_H_SIZ_L;
  277                 mip->mi.ip_src.s_addr = mip->mh.osrc;
  278         } else
  279                 msiz = MOB_H_SIZ_S;
  280 
  281         if (m->m_len < (ip->ip_hl << 2) + msiz) {
  282                 m = m_pullup(m, (ip->ip_hl << 2) + msiz);
  283                 if (m == NULL)
  284                         return;
  285                 ip = mtod(m, struct ip *);
  286                 mip = mtod(m, struct mobip_h *);
  287         }
  288 
  289         mip->mi.ip_dst.s_addr = mip->mh.odst;
  290         mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8);
  291 
  292         if (gre_in_cksum((u_int16_t *)&mip->mh, msiz) != 0) {
  293                 m_freem(m);
  294                 return;
  295         }
  296 
  297         bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) +
  298             (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2));
  299         m->m_len -= msiz;
  300         m->m_pkthdr.len -= msiz;
  301 
  302         /*
  303          * On FreeBSD, rip_input() supplies us with ip->ip_len
  304          * already converted into host byteorder and also decreases
  305          * it by the lengh of IP header, however, ip_input() expects
  306          * that this field is in the original format (network byteorder
  307          * and full size of IP packet), so that adjust accordingly.
  308          */
  309         ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz);
  310 
  311         ip->ip_sum = 0;
  312         ip->ip_sum = in_cksum(m, (ip->ip_hl << 2));
  313 
  314         if (GRE2IFP(sc)->if_bpf) {
  315                 u_int32_t af = AF_INET;
  316                 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m);
  317         }
  318 
  319         m->m_pkthdr.rcvif = GRE2IFP(sc);
  320 
  321         netisr_dispatch(NETISR_IP, m);
  322 }
  323 
  324 /*
  325  * Find the gre interface associated with our src/dst/proto set.
  326  *
  327  * XXXRW: Need some sort of drain/refcount mechanism so that the softc
  328  * reference remains valid after it's returned from gre_lookup().  Right
  329  * now, I'm thinking it should be reference-counted with a gre_dropref()
  330  * when the caller is done with the softc.  This is complicated by how
  331  * to handle destroying the gre softc; probably using a gre_drain() in
  332  * in_gre.c during destroy.
  333  */
  334 static struct gre_softc *
  335 gre_lookup(m, proto)
  336         struct mbuf *m;
  337         u_int8_t proto;
  338 {
  339         struct ip *ip = mtod(m, struct ip *);
  340         struct gre_softc *sc;
  341 
  342         mtx_lock(&gre_mtx);
  343         for (sc = LIST_FIRST(&gre_softc_list); sc != NULL;
  344              sc = LIST_NEXT(sc, sc_list)) {
  345                 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
  346                     (sc->g_src.s_addr == ip->ip_dst.s_addr) &&
  347                     (sc->g_proto == proto) &&
  348                     ((GRE2IFP(sc)->if_flags & IFF_UP) != 0)) {
  349                         mtx_unlock(&gre_mtx);
  350                         return (sc);
  351                 }
  352         }
  353         mtx_unlock(&gre_mtx);
  354 
  355         return (NULL);
  356 }
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FreeBSD/Linux Kernel Cross Reference sys/netinet/ip_gre.c

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