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

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    1 /*-
    2  * Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  *
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD$");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/jail.h>
   33 #include <sys/kernel.h>
   34 #include <sys/lock.h>
   35 #include <sys/malloc.h>
   36 #include <sys/module.h>
   37 #include <sys/mbuf.h>
   38 #include <sys/priv.h>
   39 #include <sys/proc.h>
   40 #include <sys/socket.h>
   41 #include <sys/sockio.h>
   42 #include <sys/sx.h>
   43 #include <sys/sysctl.h>
   44 #include <sys/syslog.h>
   45 
   46 #include <net/bpf.h>
   47 #include <net/ethernet.h>
   48 #include <net/if.h>
   49 #include <net/if_var.h>
   50 #include <net/if_clone.h>
   51 #include <net/if_types.h>
   52 #include <net/netisr.h>
   53 #include <net/vnet.h>
   54 #include <net/route.h>
   55 
   56 #include <netinet/in.h>
   57 #include <netinet/in_systm.h>
   58 #include <netinet/in_var.h>
   59 #include <netinet/ip.h>
   60 #include <netinet/ip_var.h>
   61 #include <netinet/ip_encap.h>
   62 
   63 #include <machine/in_cksum.h>
   64 #include <security/mac/mac_framework.h>
   65 
   66 #define MEMTU                   (1500 - sizeof(struct mobhdr))
   67 static const char mename[] = "me";
   68 static MALLOC_DEFINE(M_IFME, mename, "Minimal Encapsulation for IP");
   69 /* Minimal forwarding header RFC 2004 */
   70 struct mobhdr {
   71         uint8_t         mob_proto;      /* protocol */
   72         uint8_t         mob_flags;      /* flags */
   73 #define MOB_FLAGS_SP    0x80            /* source present */
   74         uint16_t        mob_csum;       /* header checksum */
   75         struct in_addr  mob_dst;        /* original destination address */
   76         struct in_addr  mob_src;        /* original source addr (optional) */
   77 } __packed;
   78 
   79 struct me_softc {
   80         struct ifnet            *me_ifp;
   81         u_int                   me_fibnum;
   82         struct in_addr          me_src;
   83         struct in_addr          me_dst;
   84 
   85         CK_LIST_ENTRY(me_softc) chain;
   86         CK_LIST_ENTRY(me_softc) srchash;
   87 };
   88 CK_LIST_HEAD(me_list, me_softc);
   89 #define ME2IFP(sc)              ((sc)->me_ifp)
   90 #define ME_READY(sc)            ((sc)->me_src.s_addr != 0)
   91 #define ME_RLOCK_TRACKER        struct epoch_tracker me_et
   92 #define ME_RLOCK()              epoch_enter_preempt(net_epoch_preempt, &me_et)
   93 #define ME_RUNLOCK()            epoch_exit_preempt(net_epoch_preempt, &me_et)
   94 #define ME_WAIT()               epoch_wait_preempt(net_epoch_preempt)
   95 
   96 #ifndef ME_HASH_SIZE
   97 #define ME_HASH_SIZE    (1 << 4)
   98 #endif
   99 VNET_DEFINE_STATIC(struct me_list *, me_hashtbl) = NULL;
  100 VNET_DEFINE_STATIC(struct me_list *, me_srchashtbl) = NULL;
  101 #define V_me_hashtbl            VNET(me_hashtbl)
  102 #define V_me_srchashtbl         VNET(me_srchashtbl)
  103 #define ME_HASH(src, dst)       (V_me_hashtbl[\
  104     me_hashval((src), (dst)) & (ME_HASH_SIZE - 1)])
  105 #define ME_SRCHASH(src)         (V_me_srchashtbl[\
  106     fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (ME_HASH_SIZE - 1)])
  107 
  108 static struct sx me_ioctl_sx;
  109 SX_SYSINIT(me_ioctl_sx, &me_ioctl_sx, "me_ioctl");
  110 
  111 static int      me_clone_create(struct if_clone *, int, caddr_t);
  112 static void     me_clone_destroy(struct ifnet *);
  113 VNET_DEFINE_STATIC(struct if_clone *, me_cloner);
  114 #define V_me_cloner     VNET(me_cloner)
  115 
  116 #ifdef VIMAGE
  117 static void     me_reassign(struct ifnet *, struct vnet *, char *);
  118 #endif
  119 static void     me_qflush(struct ifnet *);
  120 static int      me_transmit(struct ifnet *, struct mbuf *);
  121 static int      me_ioctl(struct ifnet *, u_long, caddr_t);
  122 static int      me_output(struct ifnet *, struct mbuf *,
  123                     const struct sockaddr *, struct route *);
  124 static int      me_input(struct mbuf *, int, int, void *);
  125 
  126 static int      me_set_tunnel(struct me_softc *, in_addr_t, in_addr_t);
  127 static void     me_delete_tunnel(struct me_softc *);
  128 
  129 SYSCTL_DECL(_net_link);
  130 static SYSCTL_NODE(_net_link, IFT_TUNNEL, me, CTLFLAG_RW, 0,
  131     "Minimal Encapsulation for IP (RFC 2004)");
  132 #ifndef MAX_ME_NEST
  133 #define MAX_ME_NEST 1
  134 #endif
  135 
  136 VNET_DEFINE_STATIC(int, max_me_nesting) = MAX_ME_NEST;
  137 #define V_max_me_nesting        VNET(max_me_nesting)
  138 SYSCTL_INT(_net_link_me, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
  139     &VNET_NAME(max_me_nesting), 0, "Max nested tunnels");
  140 
  141 static uint32_t
  142 me_hashval(in_addr_t src, in_addr_t dst)
  143 {
  144         uint32_t ret;
  145 
  146         ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
  147         return (fnv_32_buf(&dst, sizeof(dst), ret));
  148 }
  149 
  150 static struct me_list *
  151 me_hashinit(void)
  152 {
  153         struct me_list *hash;
  154         int i;
  155 
  156         hash = malloc(sizeof(struct me_list) * ME_HASH_SIZE,
  157             M_IFME, M_WAITOK);
  158         for (i = 0; i < ME_HASH_SIZE; i++)
  159                 CK_LIST_INIT(&hash[i]);
  160 
  161         return (hash);
  162 }
  163 
  164 static void
  165 vnet_me_init(const void *unused __unused)
  166 {
  167 
  168         V_me_cloner = if_clone_simple(mename, me_clone_create,
  169             me_clone_destroy, 0);
  170 }
  171 VNET_SYSINIT(vnet_me_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
  172     vnet_me_init, NULL);
  173 
  174 static void
  175 vnet_me_uninit(const void *unused __unused)
  176 {
  177 
  178         if (V_me_hashtbl != NULL) {
  179                 free(V_me_hashtbl, M_IFME);
  180                 V_me_hashtbl = NULL;
  181                 ME_WAIT();
  182                 free(V_me_srchashtbl, M_IFME);
  183         }
  184         if_clone_detach(V_me_cloner);
  185 }
  186 VNET_SYSUNINIT(vnet_me_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
  187     vnet_me_uninit, NULL);
  188 
  189 static int
  190 me_clone_create(struct if_clone *ifc, int unit, caddr_t params)
  191 {
  192         struct me_softc *sc;
  193 
  194         sc = malloc(sizeof(struct me_softc), M_IFME, M_WAITOK | M_ZERO);
  195         sc->me_fibnum = curthread->td_proc->p_fibnum;
  196         ME2IFP(sc) = if_alloc(IFT_TUNNEL);
  197         ME2IFP(sc)->if_softc = sc;
  198         if_initname(ME2IFP(sc), mename, unit);
  199 
  200         ME2IFP(sc)->if_mtu = MEMTU;;
  201         ME2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
  202         ME2IFP(sc)->if_output = me_output;
  203         ME2IFP(sc)->if_ioctl = me_ioctl;
  204         ME2IFP(sc)->if_transmit = me_transmit;
  205         ME2IFP(sc)->if_qflush = me_qflush;
  206 #ifdef VIMAGE
  207         ME2IFP(sc)->if_reassign = me_reassign;
  208 #endif
  209         ME2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
  210         ME2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
  211         if_attach(ME2IFP(sc));
  212         bpfattach(ME2IFP(sc), DLT_NULL, sizeof(u_int32_t));
  213         return (0);
  214 }
  215 
  216 #ifdef VIMAGE
  217 static void
  218 me_reassign(struct ifnet *ifp, struct vnet *new_vnet __unused,
  219     char *unused __unused)
  220 {
  221         struct me_softc *sc;
  222 
  223         sx_xlock(&me_ioctl_sx);
  224         sc = ifp->if_softc;
  225         if (sc != NULL)
  226                 me_delete_tunnel(sc);
  227         sx_xunlock(&me_ioctl_sx);
  228 }
  229 #endif /* VIMAGE */
  230 
  231 static void
  232 me_clone_destroy(struct ifnet *ifp)
  233 {
  234         struct me_softc *sc;
  235 
  236         sx_xlock(&me_ioctl_sx);
  237         sc = ifp->if_softc;
  238         me_delete_tunnel(sc);
  239         bpfdetach(ifp);
  240         if_detach(ifp);
  241         ifp->if_softc = NULL;
  242         sx_xunlock(&me_ioctl_sx);
  243 
  244         ME_WAIT();
  245         if_free(ifp);
  246         free(sc, M_IFME);
  247 }
  248 
  249 static int
  250 me_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  251 {
  252         struct ifreq *ifr = (struct ifreq *)data;
  253         struct sockaddr_in *src, *dst;
  254         struct me_softc *sc;
  255         int error;
  256 
  257         switch (cmd) {
  258         case SIOCSIFMTU:
  259                 if (ifr->ifr_mtu < 576)
  260                         return (EINVAL);
  261                 ifp->if_mtu = ifr->ifr_mtu;
  262                 return (0);
  263         case SIOCSIFADDR:
  264                 ifp->if_flags |= IFF_UP;
  265         case SIOCSIFFLAGS:
  266         case SIOCADDMULTI:
  267         case SIOCDELMULTI:
  268                 return (0);
  269         }
  270         sx_xlock(&me_ioctl_sx);
  271         sc = ifp->if_softc;
  272         if (sc == NULL) {
  273                 error = ENXIO;
  274                 goto end;
  275         }
  276         error = 0;
  277         switch (cmd) {
  278         case SIOCSIFPHYADDR:
  279                 src = &((struct in_aliasreq *)data)->ifra_addr;
  280                 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
  281                 if (src->sin_family != dst->sin_family ||
  282                     src->sin_family != AF_INET ||
  283                     src->sin_len != dst->sin_len ||
  284                     src->sin_len != sizeof(struct sockaddr_in)) {
  285                         error = EINVAL;
  286                         break;
  287                 }
  288                 if (src->sin_addr.s_addr == INADDR_ANY ||
  289                     dst->sin_addr.s_addr == INADDR_ANY) {
  290                         error = EADDRNOTAVAIL;
  291                         break;
  292                 }
  293                 error = me_set_tunnel(sc, src->sin_addr.s_addr,
  294                     dst->sin_addr.s_addr);
  295                 break;
  296         case SIOCDIFPHYADDR:
  297                 me_delete_tunnel(sc);
  298                 break;
  299         case SIOCGIFPSRCADDR:
  300         case SIOCGIFPDSTADDR:
  301                 if (!ME_READY(sc)) {
  302                         error = EADDRNOTAVAIL;
  303                         break;
  304                 }
  305                 src = (struct sockaddr_in *)&ifr->ifr_addr;
  306                 memset(src, 0, sizeof(*src));
  307                 src->sin_family = AF_INET;
  308                 src->sin_len = sizeof(*src);
  309                 switch (cmd) {
  310                 case SIOCGIFPSRCADDR:
  311                         src->sin_addr = sc->me_src;
  312                         break;
  313                 case SIOCGIFPDSTADDR:
  314                         src->sin_addr = sc->me_dst;
  315                         break;
  316                 }
  317                 error = prison_if(curthread->td_ucred, sintosa(src));
  318                 if (error != 0)
  319                         memset(src, 0, sizeof(*src));
  320                 break;
  321         case SIOCGTUNFIB:
  322                 ifr->ifr_fib = sc->me_fibnum;
  323                 break;
  324         case SIOCSTUNFIB:
  325                 if ((error = priv_check(curthread, PRIV_NET_ME)) != 0)
  326                         break;
  327                 if (ifr->ifr_fib >= rt_numfibs)
  328                         error = EINVAL;
  329                 else
  330                         sc->me_fibnum = ifr->ifr_fib;
  331                 break;
  332         default:
  333                 error = EINVAL;
  334                 break;
  335         }
  336 end:
  337         sx_xunlock(&me_ioctl_sx);
  338         return (error);
  339 }
  340 
  341 static int
  342 me_lookup(const struct mbuf *m, int off, int proto, void **arg)
  343 {
  344         const struct ip *ip;
  345         struct me_softc *sc;
  346 
  347         if (V_me_hashtbl == NULL)
  348                 return (0);
  349 
  350         MPASS(in_epoch(net_epoch_preempt));
  351         ip = mtod(m, const struct ip *);
  352         CK_LIST_FOREACH(sc, &ME_HASH(ip->ip_dst.s_addr,
  353             ip->ip_src.s_addr), chain) {
  354                 if (sc->me_src.s_addr == ip->ip_dst.s_addr &&
  355                     sc->me_dst.s_addr == ip->ip_src.s_addr) {
  356                         if ((ME2IFP(sc)->if_flags & IFF_UP) == 0)
  357                                 return (0);
  358                         *arg = sc;
  359                         return (ENCAP_DRV_LOOKUP);
  360                 }
  361         }
  362         return (0);
  363 }
  364 
  365 /*
  366  * Check that ingress address belongs to local host.
  367  */
  368 static void
  369 me_set_running(struct me_softc *sc)
  370 {
  371 
  372         if (in_localip(sc->me_src))
  373                 ME2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
  374         else
  375                 ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
  376 }
  377 
  378 /*
  379  * ifaddr_event handler.
  380  * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
  381  * source address spoofing.
  382  */
  383 static void
  384 me_srcaddr(void *arg __unused, const struct sockaddr *sa,
  385     int event __unused)
  386 {
  387         const struct sockaddr_in *sin;
  388         struct me_softc *sc;
  389 
  390         /* Check that VNET is ready */
  391         if (V_me_hashtbl == NULL)
  392                 return;
  393 
  394         MPASS(in_epoch(net_epoch_preempt));
  395         sin = (const struct sockaddr_in *)sa;
  396         CK_LIST_FOREACH(sc, &ME_SRCHASH(sin->sin_addr.s_addr), srchash) {
  397                 if (sc->me_src.s_addr != sin->sin_addr.s_addr)
  398                         continue;
  399                 me_set_running(sc);
  400         }
  401 }
  402 
  403 static int
  404 me_set_tunnel(struct me_softc *sc, in_addr_t src, in_addr_t dst)
  405 {
  406         struct me_softc *tmp;
  407 
  408         sx_assert(&me_ioctl_sx, SA_XLOCKED);
  409 
  410         if (V_me_hashtbl == NULL) {
  411                 V_me_hashtbl = me_hashinit();
  412                 V_me_srchashtbl = me_hashinit();
  413         }
  414 
  415         if (sc->me_src.s_addr == src && sc->me_dst.s_addr == dst)
  416                 return (0);
  417 
  418         CK_LIST_FOREACH(tmp, &ME_HASH(src, dst), chain) {
  419                 if (tmp == sc)
  420                         continue;
  421                 if (tmp->me_src.s_addr == src &&
  422                     tmp->me_dst.s_addr == dst)
  423                         return (EADDRNOTAVAIL);
  424         }
  425 
  426         me_delete_tunnel(sc);
  427         sc->me_dst.s_addr = dst;
  428         sc->me_src.s_addr = src;
  429         CK_LIST_INSERT_HEAD(&ME_HASH(src, dst), sc, chain);
  430         CK_LIST_INSERT_HEAD(&ME_SRCHASH(src), sc, srchash);
  431 
  432         me_set_running(sc);
  433         if_link_state_change(ME2IFP(sc), LINK_STATE_UP);
  434         return (0);
  435 }
  436 
  437 static void
  438 me_delete_tunnel(struct me_softc *sc)
  439 {
  440 
  441         sx_assert(&me_ioctl_sx, SA_XLOCKED);
  442         if (ME_READY(sc)) {
  443                 CK_LIST_REMOVE(sc, chain);
  444                 CK_LIST_REMOVE(sc, srchash);
  445                 ME_WAIT();
  446 
  447                 sc->me_src.s_addr = 0;
  448                 sc->me_dst.s_addr = 0;
  449                 ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
  450                 if_link_state_change(ME2IFP(sc), LINK_STATE_DOWN);
  451         }
  452 }
  453 
  454 static uint16_t
  455 me_in_cksum(uint16_t *p, int nwords)
  456 {
  457         uint32_t sum = 0;
  458 
  459         while (nwords-- > 0)
  460                 sum += *p++;
  461         sum = (sum >> 16) + (sum & 0xffff);
  462         sum += (sum >> 16);
  463         return (~sum);
  464 }
  465 
  466 static int
  467 me_input(struct mbuf *m, int off, int proto, void *arg)
  468 {
  469         struct me_softc *sc = arg;
  470         struct mobhdr *mh;
  471         struct ifnet *ifp;
  472         struct ip *ip;
  473         int hlen;
  474 
  475         ifp = ME2IFP(sc);
  476         /* checks for short packets */
  477         hlen = sizeof(struct mobhdr);
  478         if (m->m_pkthdr.len < sizeof(struct ip) + hlen)
  479                 hlen -= sizeof(struct in_addr);
  480         if (m->m_len < sizeof(struct ip) + hlen)
  481                 m = m_pullup(m, sizeof(struct ip) + hlen);
  482         if (m == NULL)
  483                 goto drop;
  484         mh = (struct mobhdr *)mtodo(m, sizeof(struct ip));
  485         /* check for wrong flags */
  486         if (mh->mob_flags & (~MOB_FLAGS_SP)) {
  487                 m_freem(m);
  488                 goto drop;
  489         }
  490         if (mh->mob_flags) {
  491                if (hlen != sizeof(struct mobhdr)) {
  492                         m_freem(m);
  493                         goto drop;
  494                }
  495         } else
  496                 hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
  497         /* check mobile header checksum */
  498         if (me_in_cksum((uint16_t *)mh, hlen / sizeof(uint16_t)) != 0) {
  499                 m_freem(m);
  500                 goto drop;
  501         }
  502 #ifdef MAC
  503         mac_ifnet_create_mbuf(ifp, m);
  504 #endif
  505         ip = mtod(m, struct ip *);
  506         ip->ip_dst = mh->mob_dst;
  507         ip->ip_p = mh->mob_proto;
  508         ip->ip_sum = 0;
  509         ip->ip_len = htons(m->m_pkthdr.len - hlen);
  510         if (mh->mob_flags)
  511                 ip->ip_src = mh->mob_src;
  512         memmove(mtodo(m, hlen), ip, sizeof(struct ip));
  513         m_adj(m, hlen);
  514         m_clrprotoflags(m);
  515         m->m_pkthdr.rcvif = ifp;
  516         m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
  517         M_SETFIB(m, ifp->if_fib);
  518         hlen = AF_INET;
  519         BPF_MTAP2(ifp, &hlen, sizeof(hlen), m);
  520         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
  521         if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
  522         if ((ifp->if_flags & IFF_MONITOR) != 0)
  523                 m_freem(m);
  524         else
  525                 netisr_dispatch(NETISR_IP, m);
  526         return (IPPROTO_DONE);
  527 drop:
  528         if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
  529         return (IPPROTO_DONE);
  530 }
  531 
  532 static int
  533 me_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
  534    struct route *ro __unused)
  535 {
  536         uint32_t af;
  537 
  538         if (dst->sa_family == AF_UNSPEC)
  539                 bcopy(dst->sa_data, &af, sizeof(af));
  540         else
  541                 af = dst->sa_family;
  542         m->m_pkthdr.csum_data = af;
  543         return (ifp->if_transmit(ifp, m));
  544 }
  545 
  546 #define MTAG_ME 1414491977
  547 static int
  548 me_transmit(struct ifnet *ifp, struct mbuf *m)
  549 {
  550         ME_RLOCK_TRACKER;
  551         struct mobhdr mh;
  552         struct me_softc *sc;
  553         struct ip *ip;
  554         uint32_t af;
  555         int error, hlen, plen;
  556 
  557         ME_RLOCK();
  558 #ifdef MAC
  559         error = mac_ifnet_check_transmit(ifp, m);
  560         if (error != 0)
  561                 goto drop;
  562 #endif
  563         error = ENETDOWN;
  564         sc = ifp->if_softc;
  565         if (sc == NULL || !ME_READY(sc) ||
  566             (ifp->if_flags & IFF_MONITOR) != 0 ||
  567             (ifp->if_flags & IFF_UP) == 0 ||
  568             (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
  569             (error = if_tunnel_check_nesting(ifp, m, MTAG_ME,
  570                 V_max_me_nesting)) != 0) {
  571                 m_freem(m);
  572                 goto drop;
  573         }
  574         af = m->m_pkthdr.csum_data;
  575         if (af != AF_INET) {
  576                 error = EAFNOSUPPORT;
  577                 m_freem(m);
  578                 goto drop;
  579         }
  580         if (m->m_len < sizeof(struct ip))
  581                 m = m_pullup(m, sizeof(struct ip));
  582         if (m == NULL) {
  583                 error = ENOBUFS;
  584                 goto drop;
  585         }
  586         ip = mtod(m, struct ip *);
  587         /* Fragmented datagramms shouldn't be encapsulated */
  588         if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
  589                 error = EINVAL;
  590                 m_freem(m);
  591                 goto drop;
  592         }
  593         mh.mob_proto = ip->ip_p;
  594         mh.mob_src = ip->ip_src;
  595         mh.mob_dst = ip->ip_dst;
  596         if (in_hosteq(sc->me_src, ip->ip_src)) {
  597                 hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
  598                 mh.mob_flags = 0;
  599         } else {
  600                 hlen = sizeof(struct mobhdr);
  601                 mh.mob_flags = MOB_FLAGS_SP;
  602         }
  603         BPF_MTAP2(ifp, &af, sizeof(af), m);
  604         plen = m->m_pkthdr.len;
  605         ip->ip_src = sc->me_src;
  606         ip->ip_dst = sc->me_dst;
  607         m->m_flags &= ~(M_BCAST|M_MCAST);
  608         M_SETFIB(m, sc->me_fibnum);
  609         M_PREPEND(m, hlen, M_NOWAIT);
  610         if (m == NULL) {
  611                 error = ENOBUFS;
  612                 goto drop;
  613         }
  614         if (m->m_len < sizeof(struct ip) + hlen)
  615                 m = m_pullup(m, sizeof(struct ip) + hlen);
  616         if (m == NULL) {
  617                 error = ENOBUFS;
  618                 goto drop;
  619         }
  620         memmove(mtod(m, void *), mtodo(m, hlen), sizeof(struct ip));
  621         ip = mtod(m, struct ip *);
  622         ip->ip_len = htons(m->m_pkthdr.len);
  623         ip->ip_p = IPPROTO_MOBILE;
  624         ip->ip_sum = 0;
  625         mh.mob_csum = 0;
  626         mh.mob_csum = me_in_cksum((uint16_t *)&mh, hlen / sizeof(uint16_t));
  627         bcopy(&mh, mtodo(m, sizeof(struct ip)), hlen);
  628         error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
  629 drop:
  630         if (error)
  631                 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
  632         else {
  633                 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
  634                 if_inc_counter(ifp, IFCOUNTER_OBYTES, plen);
  635         }
  636         ME_RUNLOCK();
  637         return (error);
  638 }
  639 
  640 static void
  641 me_qflush(struct ifnet *ifp __unused)
  642 {
  643 
  644 }
  645 
  646 static const struct srcaddrtab *me_srcaddrtab = NULL;
  647 static const struct encaptab *ecookie = NULL;
  648 static const struct encap_config me_encap_cfg = {
  649         .proto = IPPROTO_MOBILE,
  650         .min_length = sizeof(struct ip) + sizeof(struct mobhdr) -
  651             sizeof(in_addr_t),
  652         .exact_match = ENCAP_DRV_LOOKUP,
  653         .lookup = me_lookup,
  654         .input = me_input
  655 };
  656 
  657 static int
  658 memodevent(module_t mod, int type, void *data)
  659 {
  660 
  661         switch (type) {
  662         case MOD_LOAD:
  663                 me_srcaddrtab = ip_encap_register_srcaddr(me_srcaddr,
  664                     NULL, M_WAITOK);
  665                 ecookie = ip_encap_attach(&me_encap_cfg, NULL, M_WAITOK);
  666                 break;
  667         case MOD_UNLOAD:
  668                 ip_encap_detach(ecookie);
  669                 ip_encap_unregister_srcaddr(me_srcaddrtab);
  670                 break;
  671         default:
  672                 return (EOPNOTSUPP);
  673         }
  674         return (0);
  675 }
  676 
  677 static moduledata_t me_mod = {
  678         "if_me",
  679         memodevent,
  680         0
  681 };
  682 
  683 DECLARE_MODULE(if_me, me_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
  684 MODULE_VERSION(if_me, 1);

Cache object: b986881574050de7b11d919ee3513a78


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