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_private.h>
   51 #include <net/if_clone.h>
   52 #include <net/if_types.h>
   53 #include <net/netisr.h>
   54 #include <net/vnet.h>
   55 #include <net/route.h>
   56 
   57 #include <netinet/in.h>
   58 #include <netinet/in_systm.h>
   59 #include <netinet/in_var.h>
   60 #include <netinet/ip.h>
   61 #include <netinet/ip_var.h>
   62 #include <netinet/ip_encap.h>
   63 
   64 #include <machine/in_cksum.h>
   65 #include <security/mac/mac_framework.h>
   66 
   67 #define MEMTU                   (1500 - sizeof(struct mobhdr))
   68 static const char mename[] = "me";
   69 static MALLOC_DEFINE(M_IFME, mename, "Minimal Encapsulation for IP");
   70 /* Minimal forwarding header RFC 2004 */
   71 struct mobhdr {
   72         uint8_t         mob_proto;      /* protocol */
   73         uint8_t         mob_flags;      /* flags */
   74 #define MOB_FLAGS_SP    0x80            /* source present */
   75         uint16_t        mob_csum;       /* header checksum */
   76         struct in_addr  mob_dst;        /* original destination address */
   77         struct in_addr  mob_src;        /* original source addr (optional) */
   78 } __packed;
   79 
   80 struct me_softc {
   81         struct ifnet            *me_ifp;
   82         u_int                   me_fibnum;
   83         struct in_addr          me_src;
   84         struct in_addr          me_dst;
   85 
   86         CK_LIST_ENTRY(me_softc) chain;
   87         CK_LIST_ENTRY(me_softc) srchash;
   88 };
   89 CK_LIST_HEAD(me_list, me_softc);
   90 #define ME2IFP(sc)              ((sc)->me_ifp)
   91 #define ME_READY(sc)            ((sc)->me_src.s_addr != 0)
   92 #define ME_RLOCK_TRACKER        struct epoch_tracker me_et
   93 #define ME_RLOCK()              epoch_enter_preempt(net_epoch_preempt, &me_et)
   94 #define ME_RUNLOCK()            epoch_exit_preempt(net_epoch_preempt, &me_et)
   95 #define ME_WAIT()               epoch_wait_preempt(net_epoch_preempt)
   96 
   97 #ifndef ME_HASH_SIZE
   98 #define ME_HASH_SIZE    (1 << 4)
   99 #endif
  100 VNET_DEFINE_STATIC(struct me_list *, me_hashtbl) = NULL;
  101 VNET_DEFINE_STATIC(struct me_list *, me_srchashtbl) = NULL;
  102 #define V_me_hashtbl            VNET(me_hashtbl)
  103 #define V_me_srchashtbl         VNET(me_srchashtbl)
  104 #define ME_HASH(src, dst)       (V_me_hashtbl[\
  105     me_hashval((src), (dst)) & (ME_HASH_SIZE - 1)])
  106 #define ME_SRCHASH(src)         (V_me_srchashtbl[\
  107     fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (ME_HASH_SIZE - 1)])
  108 
  109 static struct sx me_ioctl_sx;
  110 SX_SYSINIT(me_ioctl_sx, &me_ioctl_sx, "me_ioctl");
  111 
  112 static int      me_clone_create(struct if_clone *, int, caddr_t);
  113 static void     me_clone_destroy(struct ifnet *);
  114 VNET_DEFINE_STATIC(struct if_clone *, me_cloner);
  115 #define V_me_cloner     VNET(me_cloner)
  116 
  117 #ifdef VIMAGE
  118 static void     me_reassign(struct ifnet *, struct vnet *, char *);
  119 #endif
  120 static void     me_qflush(struct ifnet *);
  121 static int      me_transmit(struct ifnet *, struct mbuf *);
  122 static int      me_ioctl(struct ifnet *, u_long, caddr_t);
  123 static int      me_output(struct ifnet *, struct mbuf *,
  124                     const struct sockaddr *, struct route *);
  125 static int      me_input(struct mbuf *, int, int, void *);
  126 
  127 static int      me_set_tunnel(struct me_softc *, in_addr_t, in_addr_t);
  128 static void     me_delete_tunnel(struct me_softc *);
  129 
  130 SYSCTL_DECL(_net_link);
  131 static SYSCTL_NODE(_net_link, IFT_TUNNEL, me, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
  132     "Minimal Encapsulation for IP (RFC 2004)");
  133 #ifndef MAX_ME_NEST
  134 #define MAX_ME_NEST 1
  135 #endif
  136 
  137 VNET_DEFINE_STATIC(int, max_me_nesting) = MAX_ME_NEST;
  138 #define V_max_me_nesting        VNET(max_me_nesting)
  139 SYSCTL_INT(_net_link_me, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
  140     &VNET_NAME(max_me_nesting), 0, "Max nested tunnels");
  141 
  142 static uint32_t
  143 me_hashval(in_addr_t src, in_addr_t dst)
  144 {
  145         uint32_t ret;
  146 
  147         ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
  148         return (fnv_32_buf(&dst, sizeof(dst), ret));
  149 }
  150 
  151 static struct me_list *
  152 me_hashinit(void)
  153 {
  154         struct me_list *hash;
  155         int i;
  156 
  157         hash = malloc(sizeof(struct me_list) * ME_HASH_SIZE,
  158             M_IFME, M_WAITOK);
  159         for (i = 0; i < ME_HASH_SIZE; i++)
  160                 CK_LIST_INIT(&hash[i]);
  161 
  162         return (hash);
  163 }
  164 
  165 static void
  166 vnet_me_init(const void *unused __unused)
  167 {
  168 
  169         V_me_cloner = if_clone_simple(mename, me_clone_create,
  170             me_clone_destroy, 0);
  171 }
  172 VNET_SYSINIT(vnet_me_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
  173     vnet_me_init, NULL);
  174 
  175 static void
  176 vnet_me_uninit(const void *unused __unused)
  177 {
  178 
  179         if (V_me_hashtbl != NULL) {
  180                 free(V_me_hashtbl, M_IFME);
  181                 V_me_hashtbl = NULL;
  182                 ME_WAIT();
  183                 free(V_me_srchashtbl, M_IFME);
  184         }
  185         if_clone_detach(V_me_cloner);
  186 }
  187 VNET_SYSUNINIT(vnet_me_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
  188     vnet_me_uninit, NULL);
  189 
  190 static int
  191 me_clone_create(struct if_clone *ifc, int unit, caddr_t params)
  192 {
  193         struct me_softc *sc;
  194 
  195         sc = malloc(sizeof(struct me_softc), M_IFME, M_WAITOK | M_ZERO);
  196         sc->me_fibnum = curthread->td_proc->p_fibnum;
  197         ME2IFP(sc) = if_alloc(IFT_TUNNEL);
  198         ME2IFP(sc)->if_softc = sc;
  199         if_initname(ME2IFP(sc), mename, unit);
  200 
  201         ME2IFP(sc)->if_mtu = MEMTU;
  202         ME2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
  203         ME2IFP(sc)->if_output = me_output;
  204         ME2IFP(sc)->if_ioctl = me_ioctl;
  205         ME2IFP(sc)->if_transmit = me_transmit;
  206         ME2IFP(sc)->if_qflush = me_qflush;
  207 #ifdef VIMAGE
  208         ME2IFP(sc)->if_reassign = me_reassign;
  209 #endif
  210         ME2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
  211         ME2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
  212         if_attach(ME2IFP(sc));
  213         bpfattach(ME2IFP(sc), DLT_NULL, sizeof(u_int32_t));
  214         return (0);
  215 }
  216 
  217 #ifdef VIMAGE
  218 static void
  219 me_reassign(struct ifnet *ifp, struct vnet *new_vnet __unused,
  220     char *unused __unused)
  221 {
  222         struct me_softc *sc;
  223 
  224         sx_xlock(&me_ioctl_sx);
  225         sc = ifp->if_softc;
  226         if (sc != NULL)
  227                 me_delete_tunnel(sc);
  228         sx_xunlock(&me_ioctl_sx);
  229 }
  230 #endif /* VIMAGE */
  231 
  232 static void
  233 me_clone_destroy(struct ifnet *ifp)
  234 {
  235         struct me_softc *sc;
  236 
  237         sx_xlock(&me_ioctl_sx);
  238         sc = ifp->if_softc;
  239         me_delete_tunnel(sc);
  240         bpfdetach(ifp);
  241         if_detach(ifp);
  242         ifp->if_softc = NULL;
  243         sx_xunlock(&me_ioctl_sx);
  244 
  245         ME_WAIT();
  246         if_free(ifp);
  247         free(sc, M_IFME);
  248 }
  249 
  250 static int
  251 me_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  252 {
  253         struct ifreq *ifr = (struct ifreq *)data;
  254         struct sockaddr_in *src, *dst;
  255         struct me_softc *sc;
  256         int error;
  257 
  258         switch (cmd) {
  259         case SIOCSIFMTU:
  260                 if (ifr->ifr_mtu < 576)
  261                         return (EINVAL);
  262                 ifp->if_mtu = ifr->ifr_mtu;
  263                 return (0);
  264         case SIOCSIFADDR:
  265                 ifp->if_flags |= IFF_UP;
  266         case SIOCSIFFLAGS:
  267         case SIOCADDMULTI:
  268         case SIOCDELMULTI:
  269                 return (0);
  270         }
  271         sx_xlock(&me_ioctl_sx);
  272         sc = ifp->if_softc;
  273         if (sc == NULL) {
  274                 error = ENXIO;
  275                 goto end;
  276         }
  277         error = 0;
  278         switch (cmd) {
  279         case SIOCSIFPHYADDR:
  280                 src = &((struct in_aliasreq *)data)->ifra_addr;
  281                 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
  282                 if (src->sin_family != dst->sin_family ||
  283                     src->sin_family != AF_INET ||
  284                     src->sin_len != dst->sin_len ||
  285                     src->sin_len != sizeof(struct sockaddr_in)) {
  286                         error = EINVAL;
  287                         break;
  288                 }
  289                 if (src->sin_addr.s_addr == INADDR_ANY ||
  290                     dst->sin_addr.s_addr == INADDR_ANY) {
  291                         error = EADDRNOTAVAIL;
  292                         break;
  293                 }
  294                 error = me_set_tunnel(sc, src->sin_addr.s_addr,
  295                     dst->sin_addr.s_addr);
  296                 break;
  297         case SIOCDIFPHYADDR:
  298                 me_delete_tunnel(sc);
  299                 break;
  300         case SIOCGIFPSRCADDR:
  301         case SIOCGIFPDSTADDR:
  302                 if (!ME_READY(sc)) {
  303                         error = EADDRNOTAVAIL;
  304                         break;
  305                 }
  306                 src = (struct sockaddr_in *)&ifr->ifr_addr;
  307                 memset(src, 0, sizeof(*src));
  308                 src->sin_family = AF_INET;
  309                 src->sin_len = sizeof(*src);
  310                 switch (cmd) {
  311                 case SIOCGIFPSRCADDR:
  312                         src->sin_addr = sc->me_src;
  313                         break;
  314                 case SIOCGIFPDSTADDR:
  315                         src->sin_addr = sc->me_dst;
  316                         break;
  317                 }
  318                 error = prison_if(curthread->td_ucred, sintosa(src));
  319                 if (error != 0)
  320                         memset(src, 0, sizeof(*src));
  321                 break;
  322         case SIOCGTUNFIB:
  323                 ifr->ifr_fib = sc->me_fibnum;
  324                 break;
  325         case SIOCSTUNFIB:
  326                 if ((error = priv_check(curthread, PRIV_NET_ME)) != 0)
  327                         break;
  328                 if (ifr->ifr_fib >= rt_numfibs)
  329                         error = EINVAL;
  330                 else
  331                         sc->me_fibnum = ifr->ifr_fib;
  332                 break;
  333         default:
  334                 error = EINVAL;
  335                 break;
  336         }
  337 end:
  338         sx_xunlock(&me_ioctl_sx);
  339         return (error);
  340 }
  341 
  342 static int
  343 me_lookup(const struct mbuf *m, int off, int proto, void **arg)
  344 {
  345         const struct ip *ip;
  346         struct me_softc *sc;
  347 
  348         if (V_me_hashtbl == NULL)
  349                 return (0);
  350 
  351         NET_EPOCH_ASSERT();
  352         ip = mtod(m, const struct ip *);
  353         CK_LIST_FOREACH(sc, &ME_HASH(ip->ip_dst.s_addr,
  354             ip->ip_src.s_addr), chain) {
  355                 if (sc->me_src.s_addr == ip->ip_dst.s_addr &&
  356                     sc->me_dst.s_addr == ip->ip_src.s_addr) {
  357                         if ((ME2IFP(sc)->if_flags & IFF_UP) == 0)
  358                                 return (0);
  359                         *arg = sc;
  360                         return (ENCAP_DRV_LOOKUP);
  361                 }
  362         }
  363         return (0);
  364 }
  365 
  366 /*
  367  * Check that ingress address belongs to local host.
  368  */
  369 static void
  370 me_set_running(struct me_softc *sc)
  371 {
  372 
  373         if (in_localip(sc->me_src))
  374                 ME2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
  375         else
  376                 ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
  377 }
  378 
  379 /*
  380  * ifaddr_event handler.
  381  * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
  382  * source address spoofing.
  383  */
  384 static void
  385 me_srcaddr(void *arg __unused, const struct sockaddr *sa,
  386     int event __unused)
  387 {
  388         const struct sockaddr_in *sin;
  389         struct me_softc *sc;
  390 
  391         /* Check that VNET is ready */
  392         if (V_me_hashtbl == NULL)
  393                 return;
  394 
  395         NET_EPOCH_ASSERT();
  396         sin = (const struct sockaddr_in *)sa;
  397         CK_LIST_FOREACH(sc, &ME_SRCHASH(sin->sin_addr.s_addr), srchash) {
  398                 if (sc->me_src.s_addr != sin->sin_addr.s_addr)
  399                         continue;
  400                 me_set_running(sc);
  401         }
  402 }
  403 
  404 static int
  405 me_set_tunnel(struct me_softc *sc, in_addr_t src, in_addr_t dst)
  406 {
  407         struct epoch_tracker et;
  408         struct me_softc *tmp;
  409 
  410         sx_assert(&me_ioctl_sx, SA_XLOCKED);
  411 
  412         if (V_me_hashtbl == NULL) {
  413                 V_me_hashtbl = me_hashinit();
  414                 V_me_srchashtbl = me_hashinit();
  415         }
  416 
  417         if (sc->me_src.s_addr == src && sc->me_dst.s_addr == dst)
  418                 return (0);
  419 
  420         CK_LIST_FOREACH(tmp, &ME_HASH(src, dst), chain) {
  421                 if (tmp == sc)
  422                         continue;
  423                 if (tmp->me_src.s_addr == src &&
  424                     tmp->me_dst.s_addr == dst)
  425                         return (EADDRNOTAVAIL);
  426         }
  427 
  428         me_delete_tunnel(sc);
  429         sc->me_dst.s_addr = dst;
  430         sc->me_src.s_addr = src;
  431         CK_LIST_INSERT_HEAD(&ME_HASH(src, dst), sc, chain);
  432         CK_LIST_INSERT_HEAD(&ME_SRCHASH(src), sc, srchash);
  433 
  434         NET_EPOCH_ENTER(et);
  435         me_set_running(sc);
  436         NET_EPOCH_EXIT(et);
  437         if_link_state_change(ME2IFP(sc), LINK_STATE_UP);
  438         return (0);
  439 }
  440 
  441 static void
  442 me_delete_tunnel(struct me_softc *sc)
  443 {
  444 
  445         sx_assert(&me_ioctl_sx, SA_XLOCKED);
  446         if (ME_READY(sc)) {
  447                 CK_LIST_REMOVE(sc, chain);
  448                 CK_LIST_REMOVE(sc, srchash);
  449                 ME_WAIT();
  450 
  451                 sc->me_src.s_addr = 0;
  452                 sc->me_dst.s_addr = 0;
  453                 ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
  454                 if_link_state_change(ME2IFP(sc), LINK_STATE_DOWN);
  455         }
  456 }
  457 
  458 static uint16_t
  459 me_in_cksum(uint16_t *p, int nwords)
  460 {
  461         uint32_t sum = 0;
  462 
  463         while (nwords-- > 0)
  464                 sum += *p++;
  465         sum = (sum >> 16) + (sum & 0xffff);
  466         sum += (sum >> 16);
  467         return (~sum);
  468 }
  469 
  470 static int
  471 me_input(struct mbuf *m, int off, int proto, void *arg)
  472 {
  473         struct me_softc *sc = arg;
  474         struct mobhdr *mh;
  475         struct ifnet *ifp;
  476         struct ip *ip;
  477         int hlen;
  478 
  479         NET_EPOCH_ASSERT();
  480 
  481         ifp = ME2IFP(sc);
  482         /* checks for short packets */
  483         hlen = sizeof(struct mobhdr);
  484         if (m->m_pkthdr.len < sizeof(struct ip) + hlen)
  485                 hlen -= sizeof(struct in_addr);
  486         if (m->m_len < sizeof(struct ip) + hlen)
  487                 m = m_pullup(m, sizeof(struct ip) + hlen);
  488         if (m == NULL)
  489                 goto drop;
  490         mh = (struct mobhdr *)mtodo(m, sizeof(struct ip));
  491         /* check for wrong flags */
  492         if (mh->mob_flags & (~MOB_FLAGS_SP)) {
  493                 m_freem(m);
  494                 goto drop;
  495         }
  496         if (mh->mob_flags) {
  497                if (hlen != sizeof(struct mobhdr)) {
  498                         m_freem(m);
  499                         goto drop;
  500                }
  501         } else
  502                 hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
  503         /* check mobile header checksum */
  504         if (me_in_cksum((uint16_t *)mh, hlen / sizeof(uint16_t)) != 0) {
  505                 m_freem(m);
  506                 goto drop;
  507         }
  508 #ifdef MAC
  509         mac_ifnet_create_mbuf(ifp, m);
  510 #endif
  511         ip = mtod(m, struct ip *);
  512         ip->ip_dst = mh->mob_dst;
  513         ip->ip_p = mh->mob_proto;
  514         ip->ip_sum = 0;
  515         ip->ip_len = htons(m->m_pkthdr.len - hlen);
  516         if (mh->mob_flags)
  517                 ip->ip_src = mh->mob_src;
  518         memmove(mtodo(m, hlen), ip, sizeof(struct ip));
  519         m_adj(m, hlen);
  520         m_clrprotoflags(m);
  521         m->m_pkthdr.rcvif = ifp;
  522         m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
  523         M_SETFIB(m, ifp->if_fib);
  524         hlen = AF_INET;
  525         BPF_MTAP2(ifp, &hlen, sizeof(hlen), m);
  526         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
  527         if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
  528         if ((ifp->if_flags & IFF_MONITOR) != 0)
  529                 m_freem(m);
  530         else
  531                 netisr_dispatch(NETISR_IP, m);
  532         return (IPPROTO_DONE);
  533 drop:
  534         if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
  535         return (IPPROTO_DONE);
  536 }
  537 
  538 static int
  539 me_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
  540    struct route *ro)
  541 {
  542         uint32_t af;
  543 
  544         if (dst->sa_family == AF_UNSPEC)
  545                 bcopy(dst->sa_data, &af, sizeof(af));
  546         else
  547                 af = RO_GET_FAMILY(ro, dst);
  548         m->m_pkthdr.csum_data = af;
  549         return (ifp->if_transmit(ifp, m));
  550 }
  551 
  552 #define MTAG_ME 1414491977
  553 static int
  554 me_transmit(struct ifnet *ifp, struct mbuf *m)
  555 {
  556         ME_RLOCK_TRACKER;
  557         struct mobhdr mh;
  558         struct me_softc *sc;
  559         struct ip *ip;
  560         uint32_t af;
  561         int error, hlen, plen;
  562 
  563         ME_RLOCK();
  564 #ifdef MAC
  565         error = mac_ifnet_check_transmit(ifp, m);
  566         if (error != 0)
  567                 goto drop;
  568 #endif
  569         error = ENETDOWN;
  570         sc = ifp->if_softc;
  571         if (sc == NULL || !ME_READY(sc) ||
  572             (ifp->if_flags & IFF_MONITOR) != 0 ||
  573             (ifp->if_flags & IFF_UP) == 0 ||
  574             (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
  575             (error = if_tunnel_check_nesting(ifp, m, MTAG_ME,
  576                 V_max_me_nesting)) != 0) {
  577                 m_freem(m);
  578                 goto drop;
  579         }
  580         af = m->m_pkthdr.csum_data;
  581         if (af != AF_INET) {
  582                 error = EAFNOSUPPORT;
  583                 m_freem(m);
  584                 goto drop;
  585         }
  586         if (m->m_len < sizeof(struct ip))
  587                 m = m_pullup(m, sizeof(struct ip));
  588         if (m == NULL) {
  589                 error = ENOBUFS;
  590                 goto drop;
  591         }
  592         ip = mtod(m, struct ip *);
  593         /* Fragmented datagramms shouldn't be encapsulated */
  594         if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
  595                 error = EINVAL;
  596                 m_freem(m);
  597                 goto drop;
  598         }
  599         mh.mob_proto = ip->ip_p;
  600         mh.mob_src = ip->ip_src;
  601         mh.mob_dst = ip->ip_dst;
  602         if (in_hosteq(sc->me_src, ip->ip_src)) {
  603                 hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
  604                 mh.mob_flags = 0;
  605         } else {
  606                 hlen = sizeof(struct mobhdr);
  607                 mh.mob_flags = MOB_FLAGS_SP;
  608         }
  609         BPF_MTAP2(ifp, &af, sizeof(af), m);
  610         plen = m->m_pkthdr.len;
  611         ip->ip_src = sc->me_src;
  612         ip->ip_dst = sc->me_dst;
  613         m->m_flags &= ~(M_BCAST|M_MCAST);
  614         M_SETFIB(m, sc->me_fibnum);
  615         M_PREPEND(m, hlen, M_NOWAIT);
  616         if (m == NULL) {
  617                 error = ENOBUFS;
  618                 goto drop;
  619         }
  620         if (m->m_len < sizeof(struct ip) + hlen)
  621                 m = m_pullup(m, sizeof(struct ip) + hlen);
  622         if (m == NULL) {
  623                 error = ENOBUFS;
  624                 goto drop;
  625         }
  626         memmove(mtod(m, void *), mtodo(m, hlen), sizeof(struct ip));
  627         ip = mtod(m, struct ip *);
  628         ip->ip_len = htons(m->m_pkthdr.len);
  629         ip->ip_p = IPPROTO_MOBILE;
  630         ip->ip_sum = 0;
  631         mh.mob_csum = 0;
  632         mh.mob_csum = me_in_cksum((uint16_t *)&mh, hlen / sizeof(uint16_t));
  633         bcopy(&mh, mtodo(m, sizeof(struct ip)), hlen);
  634         error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
  635 drop:
  636         if (error)
  637                 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
  638         else {
  639                 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
  640                 if_inc_counter(ifp, IFCOUNTER_OBYTES, plen);
  641         }
  642         ME_RUNLOCK();
  643         return (error);
  644 }
  645 
  646 static void
  647 me_qflush(struct ifnet *ifp __unused)
  648 {
  649 
  650 }
  651 
  652 static const struct srcaddrtab *me_srcaddrtab = NULL;
  653 static const struct encaptab *ecookie = NULL;
  654 static const struct encap_config me_encap_cfg = {
  655         .proto = IPPROTO_MOBILE,
  656         .min_length = sizeof(struct ip) + sizeof(struct mobhdr) -
  657             sizeof(in_addr_t),
  658         .exact_match = ENCAP_DRV_LOOKUP,
  659         .lookup = me_lookup,
  660         .input = me_input
  661 };
  662 
  663 static int
  664 memodevent(module_t mod, int type, void *data)
  665 {
  666 
  667         switch (type) {
  668         case MOD_LOAD:
  669                 me_srcaddrtab = ip_encap_register_srcaddr(me_srcaddr,
  670                     NULL, M_WAITOK);
  671                 ecookie = ip_encap_attach(&me_encap_cfg, NULL, M_WAITOK);
  672                 break;
  673         case MOD_UNLOAD:
  674                 ip_encap_detach(ecookie);
  675                 ip_encap_unregister_srcaddr(me_srcaddrtab);
  676                 break;
  677         default:
  678                 return (EOPNOTSUPP);
  679         }
  680         return (0);
  681 }
  682 
  683 static moduledata_t me_mod = {
  684         "if_me",
  685         memodevent,
  686         0
  687 };
  688 
  689 DECLARE_MODULE(if_me, me_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
  690 MODULE_VERSION(if_me, 1);
Cache object: 13f59441239a94b005feceddddb76af8
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FreeBSD/Linux Kernel Cross Reference sys/net/if_me.c

FreeBSD/Linux Kernel Cross Reference
sys/net/if_me.c
