The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/net/if_gre.c

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    1 /*      $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */
    2 /*       $FreeBSD$ */
    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  * Encapsulate L3 protocols into IP
   44  * See RFC 2784 (successor of RFC 1701 and 1702) for more details.
   45  * If_gre is compatible with Cisco GRE tunnels, so you can
   46  * have a NetBSD box as the other end of a tunnel interface of a Cisco
   47  * router. See gre(4) for more details.
   48  * Also supported:  IP in IP encaps (proto 55) as of RFC 2004
   49  */
   50 
   51 #include "opt_atalk.h"
   52 #include "opt_inet.h"
   53 #include "opt_inet6.h"
   54 
   55 #include <sys/param.h>
   56 #include <sys/kernel.h>
   57 #include <sys/malloc.h>
   58 #include <sys/module.h>
   59 #include <sys/mbuf.h>
   60 #include <sys/priv.h>
   61 #include <sys/protosw.h>
   62 #include <sys/socket.h>
   63 #include <sys/sockio.h>
   64 #include <sys/sysctl.h>
   65 #include <sys/systm.h>
   66 
   67 #include <net/ethernet.h>
   68 #include <net/if.h>
   69 #include <net/if_clone.h>
   70 #include <net/if_types.h>
   71 #include <net/route.h>
   72 
   73 #ifdef INET
   74 #include <netinet/in.h>
   75 #include <netinet/in_systm.h>
   76 #include <netinet/in_var.h>
   77 #include <netinet/ip.h>
   78 #include <netinet/ip_gre.h>
   79 #include <netinet/ip_var.h>
   80 #include <netinet/ip_encap.h>
   81 #else
   82 #error "Huh? if_gre without inet?"
   83 #endif
   84 
   85 #include <net/bpf.h>
   86 
   87 #include <net/if_gre.h>
   88 
   89 /*
   90  * It is not easy to calculate the right value for a GRE MTU.
   91  * We leave this task to the admin and use the same default that
   92  * other vendors use.
   93  */
   94 #define GREMTU  1476
   95 
   96 #define GRENAME "gre"
   97 
   98 /*
   99  * gre_mtx protects all global variables in if_gre.c.
  100  * XXX: gre_softc data not protected yet.
  101  */
  102 struct mtx gre_mtx;
  103 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
  104 
  105 struct gre_softc_head gre_softc_list;
  106 
  107 static int      gre_clone_create(struct if_clone *, int, caddr_t);
  108 static void     gre_clone_destroy(struct ifnet *);
  109 static int      gre_ioctl(struct ifnet *, u_long, caddr_t);
  110 static int      gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
  111                     struct rtentry *rt);
  112 
  113 IFC_SIMPLE_DECLARE(gre, 0);
  114 
  115 static int gre_compute_route(struct gre_softc *sc);
  116 
  117 static void     greattach(void);
  118 
  119 #ifdef INET
  120 extern struct domain inetdomain;
  121 static const struct protosw in_gre_protosw = {
  122         .pr_type =              SOCK_RAW,
  123         .pr_domain =            &inetdomain,
  124         .pr_protocol =          IPPROTO_GRE,
  125         .pr_flags =             PR_ATOMIC|PR_ADDR,
  126         .pr_input =             gre_input,
  127         .pr_output =            (pr_output_t *)rip_output,
  128         .pr_ctlinput =          rip_ctlinput,
  129         .pr_ctloutput =         rip_ctloutput,
  130         .pr_usrreqs =           &rip_usrreqs
  131 };
  132 static const struct protosw in_mobile_protosw = {
  133         .pr_type =              SOCK_RAW,
  134         .pr_domain =            &inetdomain,
  135         .pr_protocol =          IPPROTO_MOBILE,
  136         .pr_flags =             PR_ATOMIC|PR_ADDR,
  137         .pr_input =             gre_mobile_input,
  138         .pr_output =            (pr_output_t *)rip_output,
  139         .pr_ctlinput =          rip_ctlinput,
  140         .pr_ctloutput =         rip_ctloutput,
  141         .pr_usrreqs =           &rip_usrreqs
  142 };
  143 #endif
  144 
  145 SYSCTL_DECL(_net_link);
  146 SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0,
  147     "Generic Routing Encapsulation");
  148 #ifndef MAX_GRE_NEST
  149 /*
  150  * This macro controls the default upper limitation on nesting of gre tunnels.
  151  * Since, setting a large value to this macro with a careless configuration
  152  * may introduce system crash, we don't allow any nestings by default.
  153  * If you need to configure nested gre tunnels, you can define this macro
  154  * in your kernel configuration file.  However, if you do so, please be
  155  * careful to configure the tunnels so that it won't make a loop.
  156  */
  157 #define MAX_GRE_NEST 1
  158 #endif
  159 static int max_gre_nesting = MAX_GRE_NEST;
  160 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
  161     &max_gre_nesting, 0, "Max nested tunnels");
  162 
  163 /* ARGSUSED */
  164 static void
  165 greattach(void)
  166 {
  167 
  168         mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF);
  169         LIST_INIT(&gre_softc_list);
  170         if_clone_attach(&gre_cloner);
  171 }
  172 
  173 static int
  174 gre_clone_create(ifc, unit, params)
  175         struct if_clone *ifc;
  176         int unit;
  177         caddr_t params;
  178 {
  179         struct gre_softc *sc;
  180 
  181         sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO);
  182 
  183         GRE2IFP(sc) = if_alloc(IFT_TUNNEL);
  184         if (GRE2IFP(sc) == NULL) {
  185                 free(sc, M_GRE);
  186                 return (ENOSPC);
  187         }
  188 
  189         GRE2IFP(sc)->if_softc = sc;
  190         if_initname(GRE2IFP(sc), ifc->ifc_name, unit);
  191 
  192         GRE2IFP(sc)->if_snd.ifq_maxlen = IFQ_MAXLEN;
  193         GRE2IFP(sc)->if_addrlen = 0;
  194         GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */
  195         GRE2IFP(sc)->if_mtu = GREMTU;
  196         GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
  197         GRE2IFP(sc)->if_output = gre_output;
  198         GRE2IFP(sc)->if_ioctl = gre_ioctl;
  199         sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
  200         sc->g_proto = IPPROTO_GRE;
  201         GRE2IFP(sc)->if_flags |= IFF_LINK0;
  202         sc->encap = NULL;
  203         sc->called = 0;
  204         sc->wccp_ver = WCCP_V1;
  205         if_attach(GRE2IFP(sc));
  206         bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t));
  207         mtx_lock(&gre_mtx);
  208         LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
  209         mtx_unlock(&gre_mtx);
  210         return (0);
  211 }
  212 
  213 static void
  214 gre_clone_destroy(ifp)
  215         struct ifnet *ifp;
  216 {
  217         struct gre_softc *sc = ifp->if_softc;
  218 
  219         mtx_lock(&gre_mtx);
  220         LIST_REMOVE(sc, sc_list);
  221         mtx_unlock(&gre_mtx);
  222 
  223 #ifdef INET
  224         if (sc->encap != NULL)
  225                 encap_detach(sc->encap);
  226 #endif
  227         bpfdetach(ifp);
  228         if_detach(ifp);
  229         if_free(ifp);
  230         free(sc, M_GRE);
  231 }
  232 
  233 /*
  234  * The output routine. Takes a packet and encapsulates it in the protocol
  235  * given by sc->g_proto. See also RFC 1701 and RFC 2004
  236  */
  237 static int
  238 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
  239            struct rtentry *rt)
  240 {
  241         int error = 0;
  242         struct gre_softc *sc = ifp->if_softc;
  243         struct greip *gh;
  244         struct ip *ip;
  245         u_short ip_id = 0;
  246         uint8_t ip_tos = 0;
  247         u_int16_t etype = 0;
  248         struct mobile_h mob_h;
  249         u_int32_t af;
  250 
  251         /*
  252          * gre may cause infinite recursion calls when misconfigured.
  253          * We'll prevent this by introducing upper limit.
  254          */
  255         if (++(sc->called) > max_gre_nesting) {
  256                 printf("%s: gre_output: recursively called too many "
  257                        "times(%d)\n", if_name(GRE2IFP(sc)), sc->called);
  258                 m_freem(m);
  259                 error = EIO;    /* is there better errno? */
  260                 goto end;
  261         }
  262 
  263         if (!((ifp->if_flags & IFF_UP) &&
  264             (ifp->if_drv_flags & IFF_DRV_RUNNING)) ||
  265             sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
  266                 m_freem(m);
  267                 error = ENETDOWN;
  268                 goto end;
  269         }
  270 
  271         gh = NULL;
  272         ip = NULL;
  273 
  274         /* BPF writes need to be handled specially. */
  275         if (dst->sa_family == AF_UNSPEC) {
  276                 bcopy(dst->sa_data, &af, sizeof(af));
  277                 dst->sa_family = af;
  278         }
  279 
  280         if (bpf_peers_present(ifp->if_bpf)) {
  281                 af = dst->sa_family;
  282                 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
  283         }
  284 
  285         m->m_flags &= ~(M_BCAST|M_MCAST);
  286 
  287         if (sc->g_proto == IPPROTO_MOBILE) {
  288                 if (dst->sa_family == AF_INET) {
  289                         struct mbuf *m0;
  290                         int msiz;
  291 
  292                         ip = mtod(m, struct ip *);
  293 
  294                         /*
  295                          * RFC2004 specifies that fragmented diagrams shouldn't
  296                          * be encapsulated.
  297                          */
  298                         if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
  299                                 _IF_DROP(&ifp->if_snd);
  300                                 m_freem(m);
  301                                 error = EINVAL;    /* is there better errno? */
  302                                 goto end;
  303                         }
  304                         memset(&mob_h, 0, MOB_H_SIZ_L);
  305                         mob_h.proto = (ip->ip_p) << 8;
  306                         mob_h.odst = ip->ip_dst.s_addr;
  307                         ip->ip_dst.s_addr = sc->g_dst.s_addr;
  308 
  309                         /*
  310                          * If the packet comes from our host, we only change
  311                          * the destination address in the IP header.
  312                          * Else we also need to save and change the source
  313                          */
  314                         if (in_hosteq(ip->ip_src, sc->g_src)) {
  315                                 msiz = MOB_H_SIZ_S;
  316                         } else {
  317                                 mob_h.proto |= MOB_H_SBIT;
  318                                 mob_h.osrc = ip->ip_src.s_addr;
  319                                 ip->ip_src.s_addr = sc->g_src.s_addr;
  320                                 msiz = MOB_H_SIZ_L;
  321                         }
  322                         mob_h.proto = htons(mob_h.proto);
  323                         mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
  324 
  325                         if ((m->m_data - msiz) < m->m_pktdat) {
  326                                 /* need new mbuf */
  327                                 MGETHDR(m0, M_DONTWAIT, MT_DATA);
  328                                 if (m0 == NULL) {
  329                                         _IF_DROP(&ifp->if_snd);
  330                                         m_freem(m);
  331                                         error = ENOBUFS;
  332                                         goto end;
  333                                 }
  334                                 m0->m_next = m;
  335                                 m->m_data += sizeof(struct ip);
  336                                 m->m_len -= sizeof(struct ip);
  337                                 m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
  338                                 m0->m_len = msiz + sizeof(struct ip);
  339                                 m0->m_data += max_linkhdr;
  340                                 memcpy(mtod(m0, caddr_t), (caddr_t)ip,
  341                                        sizeof(struct ip));
  342                                 m = m0;
  343                         } else {  /* we have some space left in the old one */
  344                                 m->m_data -= msiz;
  345                                 m->m_len += msiz;
  346                                 m->m_pkthdr.len += msiz;
  347                                 bcopy(ip, mtod(m, caddr_t),
  348                                         sizeof(struct ip));
  349                         }
  350                         ip = mtod(m, struct ip *);
  351                         memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
  352                         ip->ip_len = ntohs(ip->ip_len) + msiz;
  353                 } else {  /* AF_INET */
  354                         _IF_DROP(&ifp->if_snd);
  355                         m_freem(m);
  356                         error = EINVAL;
  357                         goto end;
  358                 }
  359         } else if (sc->g_proto == IPPROTO_GRE) {
  360                 switch (dst->sa_family) {
  361                 case AF_INET:
  362                         ip = mtod(m, struct ip *);
  363                         ip_tos = ip->ip_tos;
  364                         ip_id = ip->ip_id;
  365                         etype = ETHERTYPE_IP;
  366                         break;
  367 #ifdef INET6
  368                 case AF_INET6:
  369                         ip_id = ip_newid();
  370                         etype = ETHERTYPE_IPV6;
  371                         break;
  372 #endif
  373 #ifdef NETATALK
  374                 case AF_APPLETALK:
  375                         etype = ETHERTYPE_ATALK;
  376                         break;
  377 #endif
  378                 default:
  379                         _IF_DROP(&ifp->if_snd);
  380                         m_freem(m);
  381                         error = EAFNOSUPPORT;
  382                         goto end;
  383                 }
  384                 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT);
  385         } else {
  386                 _IF_DROP(&ifp->if_snd);
  387                 m_freem(m);
  388                 error = EINVAL;
  389                 goto end;
  390         }
  391 
  392         if (m == NULL) {        /* mbuf allocation failed */
  393                 _IF_DROP(&ifp->if_snd);
  394                 error = ENOBUFS;
  395                 goto end;
  396         }
  397 
  398         gh = mtod(m, struct greip *);
  399         if (sc->g_proto == IPPROTO_GRE) {
  400                 /* we don't have any GRE flags for now */
  401                 memset((void *)gh, 0, sizeof(struct greip));
  402                 gh->gi_ptype = htons(etype);
  403         }
  404 
  405         gh->gi_pr = sc->g_proto;
  406         if (sc->g_proto != IPPROTO_MOBILE) {
  407                 gh->gi_src = sc->g_src;
  408                 gh->gi_dst = sc->g_dst;
  409                 ((struct ip*)gh)->ip_v = IPPROTO_IPV4;
  410                 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
  411                 ((struct ip*)gh)->ip_ttl = GRE_TTL;
  412                 ((struct ip*)gh)->ip_tos = ip_tos;
  413                 ((struct ip*)gh)->ip_id = ip_id;
  414                 gh->gi_len = m->m_pkthdr.len;
  415         }
  416 
  417         ifp->if_opackets++;
  418         ifp->if_obytes += m->m_pkthdr.len;
  419         /*
  420          * Send it off and with IP_FORWARD flag to prevent it from
  421          * overwriting the ip_id again.  ip_id is already set to the
  422          * ip_id of the encapsulated packet.
  423          */
  424         error = ip_output(m, NULL, &sc->route, IP_FORWARDING,
  425             (struct ip_moptions *)NULL, (struct inpcb *)NULL);
  426   end:
  427         sc->called = 0;
  428         if (error)
  429                 ifp->if_oerrors++;
  430         return (error);
  431 }
  432 
  433 static int
  434 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  435 {
  436         struct ifreq *ifr = (struct ifreq *)data;
  437         struct if_laddrreq *lifr = (struct if_laddrreq *)data;
  438         struct in_aliasreq *aifr = (struct in_aliasreq *)data;
  439         struct gre_softc *sc = ifp->if_softc;
  440         int s;
  441         struct sockaddr_in si;
  442         struct sockaddr *sa = NULL;
  443         int error;
  444         struct sockaddr_in sp, sm, dp, dm;
  445 
  446         error = 0;
  447 
  448         s = splnet();
  449         switch (cmd) {
  450         case SIOCSIFADDR:
  451                 ifp->if_flags |= IFF_UP;
  452                 break;
  453         case SIOCSIFDSTADDR:
  454                 break;
  455         case SIOCSIFFLAGS:
  456                 /*
  457                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  458                  * layer check?
  459                  */
  460                 if ((error = priv_check(curthread, PRIV_NET_SETIFFLAGS)) != 0)
  461                         break;
  462                 if ((ifr->ifr_flags & IFF_LINK0) != 0)
  463                         sc->g_proto = IPPROTO_GRE;
  464                 else
  465                         sc->g_proto = IPPROTO_MOBILE;
  466                 if ((ifr->ifr_flags & IFF_LINK2) != 0)
  467                         sc->wccp_ver = WCCP_V2;
  468                 else
  469                         sc->wccp_ver = WCCP_V1;
  470                 goto recompute;
  471         case SIOCSIFMTU:
  472                 /*
  473                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  474                  * layer check?
  475                  */
  476                 if ((error = priv_check(curthread, PRIV_NET_SETIFMTU)) != 0)
  477                         break;
  478                 if (ifr->ifr_mtu < 576) {
  479                         error = EINVAL;
  480                         break;
  481                 }
  482                 ifp->if_mtu = ifr->ifr_mtu;
  483                 break;
  484         case SIOCGIFMTU:
  485                 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu;
  486                 break;
  487         case SIOCADDMULTI:
  488                 /*
  489                  * XXXRW: Isn't this priv_checkr() redundant to the ifnet
  490                  * layer check?
  491                  */
  492                 if ((error = priv_check(curthread, PRIV_NET_ADDMULTI)) != 0)
  493                         break;
  494                 if (ifr == 0) {
  495                         error = EAFNOSUPPORT;
  496                         break;
  497                 }
  498                 switch (ifr->ifr_addr.sa_family) {
  499 #ifdef INET
  500                 case AF_INET:
  501                         break;
  502 #endif
  503 #ifdef INET6
  504                 case AF_INET6:
  505                         break;
  506 #endif
  507                 default:
  508                         error = EAFNOSUPPORT;
  509                         break;
  510                 }
  511                 break;
  512         case SIOCDELMULTI:
  513                 /*
  514                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  515                  * layer check?
  516                  */
  517                 if ((error = priv_check(curthread, PRIV_NET_DELIFGROUP)) != 0)
  518                         break;
  519                 if (ifr == 0) {
  520                         error = EAFNOSUPPORT;
  521                         break;
  522                 }
  523                 switch (ifr->ifr_addr.sa_family) {
  524 #ifdef INET
  525                 case AF_INET:
  526                         break;
  527 #endif
  528 #ifdef INET6
  529                 case AF_INET6:
  530                         break;
  531 #endif
  532                 default:
  533                         error = EAFNOSUPPORT;
  534                         break;
  535                 }
  536                 break;
  537         case GRESPROTO:
  538                 /*
  539                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  540                  * layer check?
  541                  */
  542                 if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
  543                         break;
  544                 sc->g_proto = ifr->ifr_flags;
  545                 switch (sc->g_proto) {
  546                 case IPPROTO_GRE:
  547                         ifp->if_flags |= IFF_LINK0;
  548                         break;
  549                 case IPPROTO_MOBILE:
  550                         ifp->if_flags &= ~IFF_LINK0;
  551                         break;
  552                 default:
  553                         error = EPROTONOSUPPORT;
  554                         break;
  555                 }
  556                 goto recompute;
  557         case GREGPROTO:
  558                 ifr->ifr_flags = sc->g_proto;
  559                 break;
  560         case GRESADDRS:
  561         case GRESADDRD:
  562                 error = priv_check(curthread, PRIV_NET_GRE);
  563                 if (error)
  564                         return (error);
  565                 /*
  566                  * set tunnel endpoints, compute a less specific route
  567                  * to the remote end and mark if as up
  568                  */
  569                 sa = &ifr->ifr_addr;
  570                 if (cmd == GRESADDRS)
  571                         sc->g_src = (satosin(sa))->sin_addr;
  572                 if (cmd == GRESADDRD)
  573                         sc->g_dst = (satosin(sa))->sin_addr;
  574         recompute:
  575 #ifdef INET
  576                 if (sc->encap != NULL) {
  577                         encap_detach(sc->encap);
  578                         sc->encap = NULL;
  579                 }
  580 #endif
  581                 if ((sc->g_src.s_addr != INADDR_ANY) &&
  582                     (sc->g_dst.s_addr != INADDR_ANY)) {
  583                         bzero(&sp, sizeof(sp));
  584                         bzero(&sm, sizeof(sm));
  585                         bzero(&dp, sizeof(dp));
  586                         bzero(&dm, sizeof(dm));
  587                         sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
  588                             sizeof(struct sockaddr_in);
  589                         sp.sin_family = sm.sin_family = dp.sin_family =
  590                             dm.sin_family = AF_INET;
  591                         sp.sin_addr = sc->g_src;
  592                         dp.sin_addr = sc->g_dst;
  593                         sm.sin_addr.s_addr = dm.sin_addr.s_addr =
  594                             INADDR_BROADCAST;
  595 #ifdef INET
  596                         sc->encap = encap_attach(AF_INET, sc->g_proto,
  597                             sintosa(&sp), sintosa(&sm), sintosa(&dp),
  598                             sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
  599                                 &in_gre_protosw : &in_mobile_protosw, sc);
  600                         if (sc->encap == NULL)
  601                                 printf("%s: unable to attach encap\n",
  602                                     if_name(GRE2IFP(sc)));
  603 #endif
  604                         if (sc->route.ro_rt != 0) /* free old route */
  605                                 RTFREE(sc->route.ro_rt);
  606                         if (gre_compute_route(sc) == 0)
  607                                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
  608                         else
  609                                 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
  610                 }
  611                 break;
  612         case GREGADDRS:
  613                 memset(&si, 0, sizeof(si));
  614                 si.sin_family = AF_INET;
  615                 si.sin_len = sizeof(struct sockaddr_in);
  616                 si.sin_addr.s_addr = sc->g_src.s_addr;
  617                 sa = sintosa(&si);
  618                 ifr->ifr_addr = *sa;
  619                 break;
  620         case GREGADDRD:
  621                 memset(&si, 0, sizeof(si));
  622                 si.sin_family = AF_INET;
  623                 si.sin_len = sizeof(struct sockaddr_in);
  624                 si.sin_addr.s_addr = sc->g_dst.s_addr;
  625                 sa = sintosa(&si);
  626                 ifr->ifr_addr = *sa;
  627                 break;
  628         case SIOCSIFPHYADDR:
  629                 /*
  630                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  631                  * layer check?
  632                  */
  633                 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
  634                         break;
  635                 if (aifr->ifra_addr.sin_family != AF_INET ||
  636                     aifr->ifra_dstaddr.sin_family != AF_INET) {
  637                         error = EAFNOSUPPORT;
  638                         break;
  639                 }
  640                 if (aifr->ifra_addr.sin_len != sizeof(si) ||
  641                     aifr->ifra_dstaddr.sin_len != sizeof(si)) {
  642                         error = EINVAL;
  643                         break;
  644                 }
  645                 sc->g_src = aifr->ifra_addr.sin_addr;
  646                 sc->g_dst = aifr->ifra_dstaddr.sin_addr;
  647                 goto recompute;
  648         case SIOCSLIFPHYADDR:
  649                 /*
  650                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  651                  * layer check?
  652                  */
  653                 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
  654                         break;
  655                 if (lifr->addr.ss_family != AF_INET ||
  656                     lifr->dstaddr.ss_family != AF_INET) {
  657                         error = EAFNOSUPPORT;
  658                         break;
  659                 }
  660                 if (lifr->addr.ss_len != sizeof(si) ||
  661                     lifr->dstaddr.ss_len != sizeof(si)) {
  662                         error = EINVAL;
  663                         break;
  664                 }
  665                 sc->g_src = (satosin(&lifr->addr))->sin_addr;
  666                 sc->g_dst =
  667                     (satosin(&lifr->dstaddr))->sin_addr;
  668                 goto recompute;
  669         case SIOCDIFPHYADDR:
  670                 /*
  671                  * XXXRW: Isn't this priv_check() redundant to the ifnet
  672                  * layer check?
  673                  */
  674                 if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
  675                         break;
  676                 sc->g_src.s_addr = INADDR_ANY;
  677                 sc->g_dst.s_addr = INADDR_ANY;
  678                 goto recompute;
  679         case SIOCGLIFPHYADDR:
  680                 if (sc->g_src.s_addr == INADDR_ANY ||
  681                     sc->g_dst.s_addr == INADDR_ANY) {
  682                         error = EADDRNOTAVAIL;
  683                         break;
  684                 }
  685                 memset(&si, 0, sizeof(si));
  686                 si.sin_family = AF_INET;
  687                 si.sin_len = sizeof(struct sockaddr_in);
  688                 si.sin_addr.s_addr = sc->g_src.s_addr;
  689                 memcpy(&lifr->addr, &si, sizeof(si));
  690                 si.sin_addr.s_addr = sc->g_dst.s_addr;
  691                 memcpy(&lifr->dstaddr, &si, sizeof(si));
  692                 break;
  693         case SIOCGIFPSRCADDR:
  694 #ifdef INET6
  695         case SIOCGIFPSRCADDR_IN6:
  696 #endif
  697                 if (sc->g_src.s_addr == INADDR_ANY) {
  698                         error = EADDRNOTAVAIL;
  699                         break;
  700                 }
  701                 memset(&si, 0, sizeof(si));
  702                 si.sin_family = AF_INET;
  703                 si.sin_len = sizeof(struct sockaddr_in);
  704                 si.sin_addr.s_addr = sc->g_src.s_addr;
  705                 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
  706                 break;
  707         case SIOCGIFPDSTADDR:
  708 #ifdef INET6
  709         case SIOCGIFPDSTADDR_IN6:
  710 #endif
  711                 if (sc->g_dst.s_addr == INADDR_ANY) {
  712                         error = EADDRNOTAVAIL;
  713                         break;
  714                 }
  715                 memset(&si, 0, sizeof(si));
  716                 si.sin_family = AF_INET;
  717                 si.sin_len = sizeof(struct sockaddr_in);
  718                 si.sin_addr.s_addr = sc->g_dst.s_addr;
  719                 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
  720                 break;
  721         default:
  722                 error = EINVAL;
  723                 break;
  724         }
  725 
  726         splx(s);
  727         return (error);
  728 }
  729 
  730 /*
  731  * computes a route to our destination that is not the one
  732  * which would be taken by ip_output(), as this one will loop back to
  733  * us. If the interface is p2p as  a--->b, then a routing entry exists
  734  * If we now send a packet to b (e.g. ping b), this will come down here
  735  * gets src=a, dst=b tacked on and would from ip_output() sent back to
  736  * if_gre.
  737  * Goal here is to compute a route to b that is less specific than
  738  * a-->b. We know that this one exists as in normal operation we have
  739  * at least a default route which matches.
  740  */
  741 static int
  742 gre_compute_route(struct gre_softc *sc)
  743 {
  744         struct route *ro;
  745         u_int32_t a, b, c;
  746 
  747         ro = &sc->route;
  748 
  749         memset(ro, 0, sizeof(struct route));
  750         ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
  751         ro->ro_dst.sa_family = AF_INET;
  752         ro->ro_dst.sa_len = sizeof(ro->ro_dst);
  753 
  754         /*
  755          * toggle last bit, so our interface is not found, but a less
  756          * specific route. I'd rather like to specify a shorter mask,
  757          * but this is not possible. Should work though. XXX
  758          * there is a simpler way ...
  759          */
  760         if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) {
  761                 a = ntohl(sc->g_dst.s_addr);
  762                 b = a & 0x01;
  763                 c = a & 0xfffffffe;
  764                 b = b ^ 0x01;
  765                 a = b | c;
  766                 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr
  767                     = htonl(a);
  768         }
  769 
  770 #ifdef DIAGNOSTIC
  771         printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)),
  772             inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
  773 #endif
  774 
  775         rtalloc(ro);
  776 
  777         /*
  778          * check if this returned a route at all and this route is no
  779          * recursion to ourself
  780          */
  781         if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
  782 #ifdef DIAGNOSTIC
  783                 if (ro->ro_rt == NULL)
  784                         printf(" - no route found!\n");
  785                 else
  786                         printf(" - route loops back to ourself!\n");
  787 #endif
  788                 return EADDRNOTAVAIL;
  789         }
  790 
  791         /*
  792          * now change it back - else ip_output will just drop
  793          * the route and search one to this interface ...
  794          */
  795         if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0)
  796                 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
  797 
  798 #ifdef DIAGNOSTIC
  799         printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
  800             inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
  801         printf("\n");
  802 #endif
  803 
  804         return 0;
  805 }
  806 
  807 /*
  808  * do a checksum of a buffer - much like in_cksum, which operates on
  809  * mbufs.
  810  */
  811 u_int16_t
  812 gre_in_cksum(u_int16_t *p, u_int len)
  813 {
  814         u_int32_t sum = 0;
  815         int nwords = len >> 1;
  816 
  817         while (nwords-- != 0)
  818                 sum += *p++;
  819 
  820         if (len & 1) {
  821                 union {
  822                         u_short w;
  823                         u_char c[2];
  824                 } u;
  825                 u.c[0] = *(u_char *)p;
  826                 u.c[1] = 0;
  827                 sum += u.w;
  828         }
  829 
  830         /* end-around-carry */
  831         sum = (sum >> 16) + (sum & 0xffff);
  832         sum += (sum >> 16);
  833         return (~sum);
  834 }
  835 
  836 static int
  837 gremodevent(module_t mod, int type, void *data)
  838 {
  839 
  840         switch (type) {
  841         case MOD_LOAD:
  842                 greattach();
  843                 break;
  844         case MOD_UNLOAD:
  845                 if_clone_detach(&gre_cloner);
  846                 mtx_destroy(&gre_mtx);
  847                 break;
  848         default:
  849                 return EOPNOTSUPP;
  850         }
  851         return 0;
  852 }
  853 
  854 static moduledata_t gre_mod = {
  855         "if_gre",
  856         gremodevent,
  857         0
  858 };
  859 
  860 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
  861 MODULE_VERSION(if_gre, 1);

Cache object: 50e08f663097b2391bbba31c805f794f


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