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

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    1 /*-
    2  * Copyright (c) 1982, 1989, 1993
    3  *      The Regents of the University of California.  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  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)if_ethersubr.c      8.1 (Berkeley) 6/10/93
   30  * $FreeBSD: releng/8.3/sys/net/if_ethersubr.c 231380 2012-02-10 13:15:11Z bz $
   31  */
   32 
   33 #include "opt_atalk.h"
   34 #include "opt_inet.h"
   35 #include "opt_inet6.h"
   36 #include "opt_ipx.h"
   37 #include "opt_netgraph.h"
   38 #include "opt_mbuf_profiling.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/kernel.h>
   43 #include <sys/lock.h>
   44 #include <sys/malloc.h>
   45 #include <sys/module.h>
   46 #include <sys/mbuf.h>
   47 #include <sys/random.h>
   48 #include <sys/rwlock.h>
   49 #include <sys/socket.h>
   50 #include <sys/sockio.h>
   51 #include <sys/sysctl.h>
   52 
   53 #include <net/if.h>
   54 #include <net/if_arp.h>
   55 #include <net/netisr.h>
   56 #include <net/route.h>
   57 #include <net/if_llc.h>
   58 #include <net/if_dl.h>
   59 #include <net/if_types.h>
   60 #include <net/bpf.h>
   61 #include <net/ethernet.h>
   62 #include <net/if_bridgevar.h>
   63 #include <net/if_vlan_var.h>
   64 #include <net/if_llatbl.h>
   65 #include <net/pf_mtag.h>
   66 #include <net/vnet.h>
   67 
   68 #if defined(INET) || defined(INET6)
   69 #include <netinet/in.h>
   70 #include <netinet/in_var.h>
   71 #include <netinet/if_ether.h>
   72 #include <netinet/ip_carp.h>
   73 #include <netinet/ip_var.h>
   74 #include <netinet/ip_fw.h>
   75 #include <netinet/ipfw/ip_fw_private.h>
   76 #endif
   77 #ifdef INET6
   78 #include <netinet6/nd6.h>
   79 #endif
   80 
   81 #ifdef IPX
   82 #include <netipx/ipx.h>
   83 #include <netipx/ipx_if.h>
   84 #endif
   85 
   86 int (*ef_inputp)(struct ifnet*, struct ether_header *eh, struct mbuf *m);
   87 int (*ef_outputp)(struct ifnet *ifp, struct mbuf **mp,
   88                 struct sockaddr *dst, short *tp, int *hlen);
   89 
   90 #ifdef NETATALK
   91 #include <netatalk/at.h>
   92 #include <netatalk/at_var.h>
   93 #include <netatalk/at_extern.h>
   94 
   95 #define llc_snap_org_code llc_un.type_snap.org_code
   96 #define llc_snap_ether_type llc_un.type_snap.ether_type
   97 
   98 extern u_char   at_org_code[3];
   99 extern u_char   aarp_org_code[3];
  100 #endif /* NETATALK */
  101 
  102 #include <security/mac/mac_framework.h>
  103 
  104 #ifdef CTASSERT
  105 CTASSERT(sizeof (struct ether_header) == ETHER_ADDR_LEN * 2 + 2);
  106 CTASSERT(sizeof (struct ether_addr) == ETHER_ADDR_LEN);
  107 #endif
  108 
  109 /* netgraph node hooks for ng_ether(4) */
  110 void    (*ng_ether_input_p)(struct ifnet *ifp, struct mbuf **mp);
  111 void    (*ng_ether_input_orphan_p)(struct ifnet *ifp, struct mbuf *m);
  112 int     (*ng_ether_output_p)(struct ifnet *ifp, struct mbuf **mp);
  113 void    (*ng_ether_attach_p)(struct ifnet *ifp);
  114 void    (*ng_ether_detach_p)(struct ifnet *ifp);
  115 
  116 void    (*vlan_input_p)(struct ifnet *, struct mbuf *);
  117 
  118 /* if_bridge(4) support */
  119 struct mbuf *(*bridge_input_p)(struct ifnet *, struct mbuf *); 
  120 int     (*bridge_output_p)(struct ifnet *, struct mbuf *, 
  121                 struct sockaddr *, struct rtentry *);
  122 void    (*bridge_dn_p)(struct mbuf *, struct ifnet *);
  123 
  124 /* if_lagg(4) support */
  125 struct mbuf *(*lagg_input_p)(struct ifnet *, struct mbuf *); 
  126 
  127 static const u_char etherbroadcastaddr[ETHER_ADDR_LEN] =
  128                         { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  129 
  130 static  int ether_resolvemulti(struct ifnet *, struct sockaddr **,
  131                 struct sockaddr *);
  132 #ifdef VIMAGE
  133 static  void ether_reassign(struct ifnet *, struct vnet *, char *);
  134 #endif
  135 
  136 /* XXX: should be in an arp support file, not here */
  137 MALLOC_DEFINE(M_ARPCOM, "arpcom", "802.* interface internals");
  138 
  139 #define ETHER_IS_BROADCAST(addr) \
  140         (bcmp(etherbroadcastaddr, (addr), ETHER_ADDR_LEN) == 0)
  141 
  142 #define senderr(e) do { error = (e); goto bad;} while (0)
  143 
  144 #if defined(INET) || defined(INET6)
  145 int
  146 ether_ipfw_chk(struct mbuf **m0, struct ifnet *dst, int shared);
  147 static VNET_DEFINE(int, ether_ipfw);
  148 #define V_ether_ipfw    VNET(ether_ipfw)
  149 #endif
  150 
  151 
  152 /*
  153  * Ethernet output routine.
  154  * Encapsulate a packet of type family for the local net.
  155  * Use trailer local net encapsulation if enough data in first
  156  * packet leaves a multiple of 512 bytes of data in remainder.
  157  */
  158 int
  159 ether_output(struct ifnet *ifp, struct mbuf *m,
  160         struct sockaddr *dst, struct route *ro)
  161 {
  162         short type;
  163         int error = 0, hdrcmplt = 0;
  164         u_char esrc[ETHER_ADDR_LEN], edst[ETHER_ADDR_LEN];
  165         struct llentry *lle = NULL;
  166         struct rtentry *rt0 = NULL;
  167         struct ether_header *eh;
  168         struct pf_mtag *t;
  169         int loop_copy = 1;
  170         int hlen;       /* link layer header length */
  171 
  172         if (ro != NULL) {
  173                 if (!(m->m_flags & (M_BCAST | M_MCAST)))
  174                         lle = ro->ro_lle;
  175                 rt0 = ro->ro_rt;
  176         }
  177 #ifdef MAC
  178         error = mac_ifnet_check_transmit(ifp, m);
  179         if (error)
  180                 senderr(error);
  181 #endif
  182 
  183         M_PROFILE(m);
  184         if (ifp->if_flags & IFF_MONITOR)
  185                 senderr(ENETDOWN);
  186         if (!((ifp->if_flags & IFF_UP) &&
  187             (ifp->if_drv_flags & IFF_DRV_RUNNING)))
  188                 senderr(ENETDOWN);
  189 
  190         hlen = ETHER_HDR_LEN;
  191         switch (dst->sa_family) {
  192 #ifdef INET
  193         case AF_INET:
  194                 if (lle != NULL && (lle->la_flags & LLE_VALID))
  195                         memcpy(edst, &lle->ll_addr.mac16, sizeof(edst));
  196                 else
  197                         error = arpresolve(ifp, rt0, m, dst, edst, &lle);
  198                 if (error)
  199                         return (error == EWOULDBLOCK ? 0 : error);
  200                 type = htons(ETHERTYPE_IP);
  201                 break;
  202         case AF_ARP:
  203         {
  204                 struct arphdr *ah;
  205                 ah = mtod(m, struct arphdr *);
  206                 ah->ar_hrd = htons(ARPHRD_ETHER);
  207 
  208                 loop_copy = 0; /* if this is for us, don't do it */
  209 
  210                 switch(ntohs(ah->ar_op)) {
  211                 case ARPOP_REVREQUEST:
  212                 case ARPOP_REVREPLY:
  213                         type = htons(ETHERTYPE_REVARP);
  214                         break;
  215                 case ARPOP_REQUEST:
  216                 case ARPOP_REPLY:
  217                 default:
  218                         type = htons(ETHERTYPE_ARP);
  219                         break;
  220                 }
  221 
  222                 if (m->m_flags & M_BCAST)
  223                         bcopy(ifp->if_broadcastaddr, edst, ETHER_ADDR_LEN);
  224                 else
  225                         bcopy(ar_tha(ah), edst, ETHER_ADDR_LEN);
  226 
  227         }
  228         break;
  229 #endif
  230 #ifdef INET6
  231         case AF_INET6:
  232                 if (lle != NULL && (lle->la_flags & LLE_VALID))
  233                         memcpy(edst, &lle->ll_addr.mac16, sizeof(edst));
  234                 else
  235                         error = nd6_storelladdr(ifp, m, dst, (u_char *)edst, &lle);
  236                 if (error)
  237                         return error;
  238                 type = htons(ETHERTYPE_IPV6);
  239                 break;
  240 #endif
  241 #ifdef IPX
  242         case AF_IPX:
  243                 if (ef_outputp) {
  244                     error = ef_outputp(ifp, &m, dst, &type, &hlen);
  245                     if (error)
  246                         goto bad;
  247                 } else
  248                     type = htons(ETHERTYPE_IPX);
  249                 bcopy((caddr_t)&(((struct sockaddr_ipx *)dst)->sipx_addr.x_host),
  250                     (caddr_t)edst, sizeof (edst));
  251                 break;
  252 #endif
  253 #ifdef NETATALK
  254         case AF_APPLETALK:
  255           {
  256             struct at_ifaddr *aa;
  257 
  258             if ((aa = at_ifawithnet((struct sockaddr_at *)dst)) == NULL)
  259                     senderr(EHOSTUNREACH); /* XXX */
  260             if (!aarpresolve(ifp, m, (struct sockaddr_at *)dst, edst)) {
  261                     ifa_free(&aa->aa_ifa);
  262                     return (0);
  263             }
  264             /*
  265              * In the phase 2 case, need to prepend an mbuf for the llc header.
  266              */
  267             if ( aa->aa_flags & AFA_PHASE2 ) {
  268                 struct llc llc;
  269 
  270                 ifa_free(&aa->aa_ifa);
  271                 M_PREPEND(m, LLC_SNAPFRAMELEN, M_DONTWAIT);
  272                 if (m == NULL)
  273                         senderr(ENOBUFS);
  274                 llc.llc_dsap = llc.llc_ssap = LLC_SNAP_LSAP;
  275                 llc.llc_control = LLC_UI;
  276                 bcopy(at_org_code, llc.llc_snap_org_code, sizeof(at_org_code));
  277                 llc.llc_snap_ether_type = htons( ETHERTYPE_AT );
  278                 bcopy(&llc, mtod(m, caddr_t), LLC_SNAPFRAMELEN);
  279                 type = htons(m->m_pkthdr.len);
  280                 hlen = LLC_SNAPFRAMELEN + ETHER_HDR_LEN;
  281             } else {
  282                 ifa_free(&aa->aa_ifa);
  283                 type = htons(ETHERTYPE_AT);
  284             }
  285             break;
  286           }
  287 #endif /* NETATALK */
  288 
  289         case pseudo_AF_HDRCMPLT:
  290                 hdrcmplt = 1;
  291                 eh = (struct ether_header *)dst->sa_data;
  292                 (void)memcpy(esrc, eh->ether_shost, sizeof (esrc));
  293                 /* FALLTHROUGH */
  294 
  295         case AF_UNSPEC:
  296                 loop_copy = 0; /* if this is for us, don't do it */
  297                 eh = (struct ether_header *)dst->sa_data;
  298                 (void)memcpy(edst, eh->ether_dhost, sizeof (edst));
  299                 type = eh->ether_type;
  300                 break;
  301 
  302         default:
  303                 if_printf(ifp, "can't handle af%d\n", dst->sa_family);
  304                 senderr(EAFNOSUPPORT);
  305         }
  306 
  307         if (lle != NULL && (lle->la_flags & LLE_IFADDR)) {
  308                 int csum_flags = 0;
  309                 if (m->m_pkthdr.csum_flags & CSUM_IP)
  310                         csum_flags |= (CSUM_IP_CHECKED|CSUM_IP_VALID);
  311                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
  312                         csum_flags |= (CSUM_DATA_VALID|CSUM_PSEUDO_HDR);
  313                 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
  314                         csum_flags |= CSUM_SCTP_VALID;
  315                 m->m_pkthdr.csum_flags |= csum_flags;
  316                 m->m_pkthdr.csum_data = 0xffff;
  317                 return (if_simloop(ifp, m, dst->sa_family, 0));
  318         }
  319 
  320         /*
  321          * Add local net header.  If no space in first mbuf,
  322          * allocate another.
  323          */
  324         M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
  325         if (m == NULL)
  326                 senderr(ENOBUFS);
  327         eh = mtod(m, struct ether_header *);
  328         (void)memcpy(&eh->ether_type, &type,
  329                 sizeof(eh->ether_type));
  330         (void)memcpy(eh->ether_dhost, edst, sizeof (edst));
  331         if (hdrcmplt)
  332                 (void)memcpy(eh->ether_shost, esrc,
  333                         sizeof(eh->ether_shost));
  334         else
  335                 (void)memcpy(eh->ether_shost, IF_LLADDR(ifp),
  336                         sizeof(eh->ether_shost));
  337 
  338         /*
  339          * If a simplex interface, and the packet is being sent to our
  340          * Ethernet address or a broadcast address, loopback a copy.
  341          * XXX To make a simplex device behave exactly like a duplex
  342          * device, we should copy in the case of sending to our own
  343          * ethernet address (thus letting the original actually appear
  344          * on the wire). However, we don't do that here for security
  345          * reasons and compatibility with the original behavior.
  346          */
  347         if ((ifp->if_flags & IFF_SIMPLEX) && loop_copy &&
  348             ((t = pf_find_mtag(m)) == NULL || !t->routed)) {
  349                 int csum_flags = 0;
  350 
  351                 if (m->m_pkthdr.csum_flags & CSUM_IP)
  352                         csum_flags |= (CSUM_IP_CHECKED|CSUM_IP_VALID);
  353                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
  354                         csum_flags |= (CSUM_DATA_VALID|CSUM_PSEUDO_HDR);
  355                 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
  356                         csum_flags |= CSUM_SCTP_VALID;
  357 
  358                 if (m->m_flags & M_BCAST) {
  359                         struct mbuf *n;
  360 
  361                         /*
  362                          * Because if_simloop() modifies the packet, we need a
  363                          * writable copy through m_dup() instead of a readonly
  364                          * one as m_copy[m] would give us. The alternative would
  365                          * be to modify if_simloop() to handle the readonly mbuf,
  366                          * but performancewise it is mostly equivalent (trading
  367                          * extra data copying vs. extra locking).
  368                          *
  369                          * XXX This is a local workaround.  A number of less
  370                          * often used kernel parts suffer from the same bug.
  371                          * See PR kern/105943 for a proposed general solution.
  372                          */
  373                         if ((n = m_dup(m, M_DONTWAIT)) != NULL) {
  374                                 n->m_pkthdr.csum_flags |= csum_flags;
  375                                 if (csum_flags & CSUM_DATA_VALID)
  376                                         n->m_pkthdr.csum_data = 0xffff;
  377                                 (void)if_simloop(ifp, n, dst->sa_family, hlen);
  378                         } else
  379                                 ifp->if_iqdrops++;
  380                 } else if (bcmp(eh->ether_dhost, eh->ether_shost,
  381                                 ETHER_ADDR_LEN) == 0) {
  382                         m->m_pkthdr.csum_flags |= csum_flags;
  383                         if (csum_flags & CSUM_DATA_VALID)
  384                                 m->m_pkthdr.csum_data = 0xffff;
  385                         (void) if_simloop(ifp, m, dst->sa_family, hlen);
  386                         return (0);     /* XXX */
  387                 }
  388         }
  389 
  390        /*
  391         * Bridges require special output handling.
  392         */
  393         if (ifp->if_bridge) {
  394                 BRIDGE_OUTPUT(ifp, m, error);
  395                 return (error);
  396         }
  397 
  398 #if defined(INET) || defined(INET6)
  399         if (ifp->if_carp &&
  400             (error = (*carp_output_p)(ifp, m, dst, NULL)))
  401                 goto bad;
  402 #endif
  403 
  404         /* Handle ng_ether(4) processing, if any */
  405         if (IFP2AC(ifp)->ac_netgraph != NULL) {
  406                 KASSERT(ng_ether_output_p != NULL,
  407                     ("ng_ether_output_p is NULL"));
  408                 if ((error = (*ng_ether_output_p)(ifp, &m)) != 0) {
  409 bad:                    if (m != NULL)
  410                                 m_freem(m);
  411                         return (error);
  412                 }
  413                 if (m == NULL)
  414                         return (0);
  415         }
  416 
  417         /* Continue with link-layer output */
  418         return ether_output_frame(ifp, m);
  419 }
  420 
  421 /*
  422  * Ethernet link layer output routine to send a raw frame to the device.
  423  *
  424  * This assumes that the 14 byte Ethernet header is present and contiguous
  425  * in the first mbuf (if BRIDGE'ing).
  426  */
  427 int
  428 ether_output_frame(struct ifnet *ifp, struct mbuf *m)
  429 {
  430 #if defined(INET) || defined(INET6)
  431 
  432         if (V_ip_fw_chk_ptr && V_ether_ipfw != 0) {
  433                 if (ether_ipfw_chk(&m, ifp, 0) == 0) {
  434                         if (m) {
  435                                 m_freem(m);
  436                                 return EACCES;  /* pkt dropped */
  437                         } else
  438                                 return 0;       /* consumed e.g. in a pipe */
  439                 }
  440         }
  441 #endif
  442 
  443         /*
  444          * Queue message on interface, update output statistics if
  445          * successful, and start output if interface not yet active.
  446          */
  447         return ((ifp->if_transmit)(ifp, m));
  448 }
  449 
  450 #if defined(INET) || defined(INET6)
  451 /*
  452  * ipfw processing for ethernet packets (in and out).
  453  * The second parameter is NULL from ether_demux, and ifp from
  454  * ether_output_frame.
  455  */
  456 int
  457 ether_ipfw_chk(struct mbuf **m0, struct ifnet *dst, int shared)
  458 {
  459         struct ether_header *eh;
  460         struct ether_header save_eh;
  461         struct mbuf *m;
  462         int i;
  463         struct ip_fw_args args;
  464         struct m_tag *mtag;
  465 
  466         /* fetch start point from rule, if any */
  467         mtag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL);
  468         if (mtag == NULL) {
  469                 args.rule.slot = 0;
  470         } else {
  471                         /* dummynet packet, already partially processed */
  472                 struct ipfw_rule_ref *r;
  473 
  474                 /* XXX can we free it after use ? */
  475                 mtag->m_tag_id = PACKET_TAG_NONE;
  476                 r = (struct ipfw_rule_ref *)(mtag + 1);
  477                 if (r->info & IPFW_ONEPASS)
  478                         return (1);
  479                 args.rule = *r;
  480         }
  481 
  482         /*
  483          * I need some amt of data to be contiguous, and in case others need
  484          * the packet (shared==1) also better be in the first mbuf.
  485          */
  486         m = *m0;
  487         i = min( m->m_pkthdr.len, max_protohdr);
  488         if ( shared || m->m_len < i) {
  489                 m = m_pullup(m, i);
  490                 if (m == NULL) {
  491                         *m0 = m;
  492                         return 0;
  493                 }
  494         }
  495         eh = mtod(m, struct ether_header *);
  496         save_eh = *eh;                  /* save copy for restore below */
  497         m_adj(m, ETHER_HDR_LEN);        /* strip ethernet header */
  498 
  499         args.m = m;             /* the packet we are looking at         */
  500         args.oif = dst;         /* destination, if any                  */
  501         args.next_hop = NULL;   /* we do not support forward yet        */
  502         args.eh = &save_eh;     /* MAC header for bridged/MAC packets   */
  503         args.inp = NULL;        /* used by ipfw uid/gid/jail rules      */
  504         i = V_ip_fw_chk_ptr(&args);
  505         m = args.m;
  506         if (m != NULL) {
  507                 /*
  508                  * Restore Ethernet header, as needed, in case the
  509                  * mbuf chain was replaced by ipfw.
  510                  */
  511                 M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
  512                 if (m == NULL) {
  513                         *m0 = m;
  514                         return 0;
  515                 }
  516                 if (eh != mtod(m, struct ether_header *))
  517                         bcopy(&save_eh, mtod(m, struct ether_header *),
  518                                 ETHER_HDR_LEN);
  519         }
  520         *m0 = m;
  521 
  522         if (i == IP_FW_DENY) /* drop */
  523                 return 0;
  524 
  525         KASSERT(m != NULL, ("ether_ipfw_chk: m is NULL"));
  526 
  527         if (i == IP_FW_PASS) /* a PASS rule.  */
  528                 return 1;
  529 
  530         if (ip_dn_io_ptr && (i == IP_FW_DUMMYNET)) {
  531                 int dir;
  532                 /*
  533                  * Pass the pkt to dummynet, which consumes it.
  534                  * If shared, make a copy and keep the original.
  535                  */
  536                 if (shared) {
  537                         m = m_copypacket(m, M_DONTWAIT);
  538                         if (m == NULL)
  539                                 return 0;
  540                 } else {
  541                         /*
  542                          * Pass the original to dummynet and
  543                          * nothing back to the caller
  544                          */
  545                         *m0 = NULL ;
  546                 }
  547                 dir = PROTO_LAYER2 | (dst ? DIR_OUT : DIR_IN);
  548                 ip_dn_io_ptr(&m, dir, &args);
  549                 return 0;
  550         }
  551         /*
  552          * XXX at some point add support for divert/forward actions.
  553          * If none of the above matches, we have to drop the pkt.
  554          */
  555         return 0;
  556 }
  557 #endif
  558 
  559 /*
  560  * Process a received Ethernet packet; the packet is in the
  561  * mbuf chain m with the ethernet header at the front.
  562  */
  563 static void
  564 ether_input(struct ifnet *ifp, struct mbuf *m)
  565 {
  566         struct ether_header *eh;
  567         u_short etype;
  568 
  569         if ((ifp->if_flags & IFF_UP) == 0) {
  570                 m_freem(m);
  571                 return;
  572         }
  573 #ifdef DIAGNOSTIC
  574         if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
  575                 if_printf(ifp, "discard frame at !IFF_DRV_RUNNING\n");
  576                 m_freem(m);
  577                 return;
  578         }
  579 #endif
  580         /*
  581          * Do consistency checks to verify assumptions
  582          * made by code past this point.
  583          */
  584         if ((m->m_flags & M_PKTHDR) == 0) {
  585                 if_printf(ifp, "discard frame w/o packet header\n");
  586                 ifp->if_ierrors++;
  587                 m_freem(m);
  588                 return;
  589         }
  590         if (m->m_len < ETHER_HDR_LEN) {
  591                 /* XXX maybe should pullup? */
  592                 if_printf(ifp, "discard frame w/o leading ethernet "
  593                                 "header (len %u pkt len %u)\n",
  594                                 m->m_len, m->m_pkthdr.len);
  595                 ifp->if_ierrors++;
  596                 m_freem(m);
  597                 return;
  598         }
  599         eh = mtod(m, struct ether_header *);
  600         etype = ntohs(eh->ether_type);
  601         if (m->m_pkthdr.rcvif == NULL) {
  602                 if_printf(ifp, "discard frame w/o interface pointer\n");
  603                 ifp->if_ierrors++;
  604                 m_freem(m);
  605                 return;
  606         }
  607 #ifdef DIAGNOSTIC
  608         if (m->m_pkthdr.rcvif != ifp) {
  609                 if_printf(ifp, "Warning, frame marked as received on %s\n",
  610                         m->m_pkthdr.rcvif->if_xname);
  611         }
  612 #endif
  613 
  614         CURVNET_SET_QUIET(ifp->if_vnet);
  615 
  616         if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
  617                 if (ETHER_IS_BROADCAST(eh->ether_dhost))
  618                         m->m_flags |= M_BCAST;
  619                 else
  620                         m->m_flags |= M_MCAST;
  621                 ifp->if_imcasts++;
  622         }
  623 
  624 #ifdef MAC
  625         /*
  626          * Tag the mbuf with an appropriate MAC label before any other
  627          * consumers can get to it.
  628          */
  629         mac_ifnet_create_mbuf(ifp, m);
  630 #endif
  631 
  632         /*
  633          * Give bpf a chance at the packet.
  634          */
  635         ETHER_BPF_MTAP(ifp, m);
  636 
  637         /*
  638          * If the CRC is still on the packet, trim it off. We do this once
  639          * and once only in case we are re-entered. Nothing else on the
  640          * Ethernet receive path expects to see the FCS.
  641          */
  642         if (m->m_flags & M_HASFCS) {
  643                 m_adj(m, -ETHER_CRC_LEN);
  644                 m->m_flags &= ~M_HASFCS;
  645         }
  646 
  647         ifp->if_ibytes += m->m_pkthdr.len;
  648 
  649         /* Allow monitor mode to claim this frame, after stats are updated. */
  650         if (ifp->if_flags & IFF_MONITOR) {
  651                 m_freem(m);
  652                 CURVNET_RESTORE();
  653                 return;
  654         }
  655 
  656         /* Handle input from a lagg(4) port */
  657         if (ifp->if_type == IFT_IEEE8023ADLAG) {
  658                 KASSERT(lagg_input_p != NULL,
  659                     ("%s: if_lagg not loaded!", __func__));
  660                 m = (*lagg_input_p)(ifp, m);
  661                 if (m != NULL)
  662                         ifp = m->m_pkthdr.rcvif;
  663                 else 
  664                         return;
  665         }
  666 
  667         /*
  668          * If the hardware did not process an 802.1Q tag, do this now,
  669          * to allow 802.1P priority frames to be passed to the main input
  670          * path correctly.
  671          * TODO: Deal with Q-in-Q frames, but not arbitrary nesting levels.
  672          */
  673         if ((m->m_flags & M_VLANTAG) == 0 && etype == ETHERTYPE_VLAN) {
  674                 struct ether_vlan_header *evl;
  675 
  676                 if (m->m_len < sizeof(*evl) &&
  677                     (m = m_pullup(m, sizeof(*evl))) == NULL) {
  678 #ifdef DIAGNOSTIC
  679                         if_printf(ifp, "cannot pullup VLAN header\n");
  680 #endif
  681                         ifp->if_ierrors++;
  682                         m_freem(m);
  683                         return;
  684                 }
  685 
  686                 evl = mtod(m, struct ether_vlan_header *);
  687                 m->m_pkthdr.ether_vtag = ntohs(evl->evl_tag);
  688                 m->m_flags |= M_VLANTAG;
  689 
  690                 bcopy((char *)evl, (char *)evl + ETHER_VLAN_ENCAP_LEN,
  691                     ETHER_HDR_LEN - ETHER_TYPE_LEN);
  692                 m_adj(m, ETHER_VLAN_ENCAP_LEN);
  693         }
  694 
  695         M_SETFIB(m, ifp->if_fib);
  696 
  697         /* Allow ng_ether(4) to claim this frame. */
  698         if (IFP2AC(ifp)->ac_netgraph != NULL) {
  699                 KASSERT(ng_ether_input_p != NULL,
  700                     ("%s: ng_ether_input_p is NULL", __func__));
  701                 m->m_flags &= ~M_PROMISC;
  702                 (*ng_ether_input_p)(ifp, &m);
  703                 if (m == NULL) {
  704                         CURVNET_RESTORE();
  705                         return;
  706                 }
  707         }
  708 
  709         /*
  710          * Allow if_bridge(4) to claim this frame.
  711          * The BRIDGE_INPUT() macro will update ifp if the bridge changed it
  712          * and the frame should be delivered locally.
  713          */
  714         if (ifp->if_bridge != NULL) {
  715                 m->m_flags &= ~M_PROMISC;
  716                 BRIDGE_INPUT(ifp, m);
  717                 if (m == NULL) {
  718                         CURVNET_RESTORE();
  719                         return;
  720                 }
  721         }
  722 
  723 #if defined(INET) || defined(INET6)
  724         /*
  725          * Clear M_PROMISC on frame so that carp(4) will see it when the
  726          * mbuf flows up to Layer 3.
  727          * FreeBSD's implementation of carp(4) uses the inprotosw
  728          * to dispatch IPPROTO_CARP. carp(4) also allocates its own
  729          * Ethernet addresses of the form 00:00:5e:00:01:xx, which
  730          * is outside the scope of the M_PROMISC test below.
  731          * TODO: Maintain a hash table of ethernet addresses other than
  732          * ether_dhost which may be active on this ifp.
  733          */
  734         if (ifp->if_carp && (*carp_forus_p)(ifp, eh->ether_dhost)) {
  735                 m->m_flags &= ~M_PROMISC;
  736         } else
  737 #endif
  738         {
  739                 /*
  740                  * If the frame received was not for our MAC address, set the
  741                  * M_PROMISC flag on the mbuf chain. The frame may need to
  742                  * be seen by the rest of the Ethernet input path in case of
  743                  * re-entry (e.g. bridge, vlan, netgraph) but should not be
  744                  * seen by upper protocol layers.
  745                  */
  746                 if (!ETHER_IS_MULTICAST(eh->ether_dhost) &&
  747                     bcmp(IF_LLADDR(ifp), eh->ether_dhost, ETHER_ADDR_LEN) != 0)
  748                         m->m_flags |= M_PROMISC;
  749         }
  750 
  751         /* First chunk of an mbuf contains good entropy */
  752         if (harvest.ethernet)
  753                 random_harvest(m, 16, 3, 0, RANDOM_NET);
  754 
  755         ether_demux(ifp, m);
  756         CURVNET_RESTORE();
  757 }
  758 
  759 /*
  760  * Upper layer processing for a received Ethernet packet.
  761  */
  762 void
  763 ether_demux(struct ifnet *ifp, struct mbuf *m)
  764 {
  765         struct ether_header *eh;
  766         int isr;
  767         u_short ether_type;
  768 #if defined(NETATALK)
  769         struct llc *l;
  770 #endif
  771 
  772         KASSERT(ifp != NULL, ("%s: NULL interface pointer", __func__));
  773 
  774 #if defined(INET) || defined(INET6)
  775         /*
  776          * Allow dummynet and/or ipfw to claim the frame.
  777          * Do not do this for PROMISC frames in case we are re-entered.
  778          */
  779         if (V_ip_fw_chk_ptr && V_ether_ipfw != 0 && !(m->m_flags & M_PROMISC)) {
  780                 if (ether_ipfw_chk(&m, NULL, 0) == 0) {
  781                         if (m)
  782                                 m_freem(m);     /* dropped; free mbuf chain */
  783                         return;                 /* consumed */
  784                 }
  785         }
  786 #endif
  787         eh = mtod(m, struct ether_header *);
  788         ether_type = ntohs(eh->ether_type);
  789 
  790         /*
  791          * If this frame has a VLAN tag other than 0, call vlan_input()
  792          * if its module is loaded. Otherwise, drop.
  793          */
  794         if ((m->m_flags & M_VLANTAG) &&
  795             EVL_VLANOFTAG(m->m_pkthdr.ether_vtag) != 0) {
  796                 if (ifp->if_vlantrunk == NULL) {
  797                         ifp->if_noproto++;
  798                         m_freem(m);
  799                         return;
  800                 }
  801                 KASSERT(vlan_input_p != NULL,("%s: VLAN not loaded!",
  802                     __func__));
  803                 /* Clear before possibly re-entering ether_input(). */
  804                 m->m_flags &= ~M_PROMISC;
  805                 (*vlan_input_p)(ifp, m);
  806                 return;
  807         }
  808 
  809         /*
  810          * Pass promiscuously received frames to the upper layer if the user
  811          * requested this by setting IFF_PPROMISC. Otherwise, drop them.
  812          */
  813         if ((ifp->if_flags & IFF_PPROMISC) == 0 && (m->m_flags & M_PROMISC)) {
  814                 m_freem(m);
  815                 return;
  816         }
  817 
  818         /*
  819          * Reset layer specific mbuf flags to avoid confusing upper layers.
  820          * Strip off Ethernet header.
  821          */
  822         m->m_flags &= ~M_VLANTAG;
  823         m->m_flags &= ~(M_PROTOFLAGS);
  824         m_adj(m, ETHER_HDR_LEN);
  825 
  826         /*
  827          * Dispatch frame to upper layer.
  828          */
  829         switch (ether_type) {
  830 #ifdef INET
  831         case ETHERTYPE_IP:
  832                 if ((m = ip_fastforward(m)) == NULL)
  833                         return;
  834                 isr = NETISR_IP;
  835                 break;
  836 
  837         case ETHERTYPE_ARP:
  838                 if (ifp->if_flags & IFF_NOARP) {
  839                         /* Discard packet if ARP is disabled on interface */
  840                         m_freem(m);
  841                         return;
  842                 }
  843                 isr = NETISR_ARP;
  844                 break;
  845 #endif
  846 #ifdef IPX
  847         case ETHERTYPE_IPX:
  848                 if (ef_inputp && ef_inputp(ifp, eh, m) == 0)
  849                         return;
  850                 isr = NETISR_IPX;
  851                 break;
  852 #endif
  853 #ifdef INET6
  854         case ETHERTYPE_IPV6:
  855                 isr = NETISR_IPV6;
  856                 break;
  857 #endif
  858 #ifdef NETATALK
  859         case ETHERTYPE_AT:
  860                 isr = NETISR_ATALK1;
  861                 break;
  862         case ETHERTYPE_AARP:
  863                 isr = NETISR_AARP;
  864                 break;
  865 #endif /* NETATALK */
  866         default:
  867 #ifdef IPX
  868                 if (ef_inputp && ef_inputp(ifp, eh, m) == 0)
  869                         return;
  870 #endif /* IPX */
  871 #if defined(NETATALK)
  872                 if (ether_type > ETHERMTU)
  873                         goto discard;
  874                 l = mtod(m, struct llc *);
  875                 if (l->llc_dsap == LLC_SNAP_LSAP &&
  876                     l->llc_ssap == LLC_SNAP_LSAP &&
  877                     l->llc_control == LLC_UI) {
  878                         if (bcmp(&(l->llc_snap_org_code)[0], at_org_code,
  879                             sizeof(at_org_code)) == 0 &&
  880                             ntohs(l->llc_snap_ether_type) == ETHERTYPE_AT) {
  881                                 m_adj(m, LLC_SNAPFRAMELEN);
  882                                 isr = NETISR_ATALK2;
  883                                 break;
  884                         }
  885                         if (bcmp(&(l->llc_snap_org_code)[0], aarp_org_code,
  886                             sizeof(aarp_org_code)) == 0 &&
  887                             ntohs(l->llc_snap_ether_type) == ETHERTYPE_AARP) {
  888                                 m_adj(m, LLC_SNAPFRAMELEN);
  889                                 isr = NETISR_AARP;
  890                                 break;
  891                         }
  892                 }
  893 #endif /* NETATALK */
  894                 goto discard;
  895         }
  896         netisr_dispatch(isr, m);
  897         return;
  898 
  899 discard:
  900         /*
  901          * Packet is to be discarded.  If netgraph is present,
  902          * hand the packet to it for last chance processing;
  903          * otherwise dispose of it.
  904          */
  905         if (IFP2AC(ifp)->ac_netgraph != NULL) {
  906                 KASSERT(ng_ether_input_orphan_p != NULL,
  907                     ("ng_ether_input_orphan_p is NULL"));
  908                 /*
  909                  * Put back the ethernet header so netgraph has a
  910                  * consistent view of inbound packets.
  911                  */
  912                 M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
  913                 (*ng_ether_input_orphan_p)(ifp, m);
  914                 return;
  915         }
  916         m_freem(m);
  917 }
  918 
  919 /*
  920  * Convert Ethernet address to printable (loggable) representation.
  921  * This routine is for compatibility; it's better to just use
  922  *
  923  *      printf("%6D", <pointer to address>, ":");
  924  *
  925  * since there's no static buffer involved.
  926  */
  927 char *
  928 ether_sprintf(const u_char *ap)
  929 {
  930         static char etherbuf[18];
  931         snprintf(etherbuf, sizeof (etherbuf), "%6D", ap, ":");
  932         return (etherbuf);
  933 }
  934 
  935 /*
  936  * Perform common duties while attaching to interface list
  937  */
  938 void
  939 ether_ifattach(struct ifnet *ifp, const u_int8_t *lla)
  940 {
  941         int i;
  942         struct ifaddr *ifa;
  943         struct sockaddr_dl *sdl;
  944 
  945         ifp->if_addrlen = ETHER_ADDR_LEN;
  946         ifp->if_hdrlen = ETHER_HDR_LEN;
  947         if_attach(ifp);
  948         ifp->if_mtu = ETHERMTU;
  949         ifp->if_output = ether_output;
  950         ifp->if_input = ether_input;
  951         ifp->if_resolvemulti = ether_resolvemulti;
  952 #ifdef VIMAGE
  953         ifp->if_reassign = ether_reassign;
  954 #endif
  955         if (ifp->if_baudrate == 0)
  956                 ifp->if_baudrate = IF_Mbps(10);         /* just a default */
  957         ifp->if_broadcastaddr = etherbroadcastaddr;
  958 
  959         ifa = ifp->if_addr;
  960         KASSERT(ifa != NULL, ("%s: no lladdr!\n", __func__));
  961         sdl = (struct sockaddr_dl *)ifa->ifa_addr;
  962         sdl->sdl_type = IFT_ETHER;
  963         sdl->sdl_alen = ifp->if_addrlen;
  964         bcopy(lla, LLADDR(sdl), ifp->if_addrlen);
  965 
  966         bpfattach(ifp, DLT_EN10MB, ETHER_HDR_LEN);
  967         if (ng_ether_attach_p != NULL)
  968                 (*ng_ether_attach_p)(ifp);
  969 
  970         /* Announce Ethernet MAC address if non-zero. */
  971         for (i = 0; i < ifp->if_addrlen; i++)
  972                 if (lla[i] != 0)
  973                         break; 
  974         if (i != ifp->if_addrlen)
  975                 if_printf(ifp, "Ethernet address: %6D\n", lla, ":");
  976 }
  977 
  978 /*
  979  * Perform common duties while detaching an Ethernet interface
  980  */
  981 void
  982 ether_ifdetach(struct ifnet *ifp)
  983 {
  984         if (IFP2AC(ifp)->ac_netgraph != NULL) {
  985                 KASSERT(ng_ether_detach_p != NULL,
  986                     ("ng_ether_detach_p is NULL"));
  987                 (*ng_ether_detach_p)(ifp);
  988         }
  989 
  990         bpfdetach(ifp);
  991         if_detach(ifp);
  992 }
  993 
  994 #ifdef VIMAGE
  995 void
  996 ether_reassign(struct ifnet *ifp, struct vnet *new_vnet, char *unused __unused)
  997 {
  998 
  999         if (IFP2AC(ifp)->ac_netgraph != NULL) {
 1000                 KASSERT(ng_ether_detach_p != NULL,
 1001                     ("ng_ether_detach_p is NULL"));
 1002                 (*ng_ether_detach_p)(ifp);
 1003         }
 1004 
 1005         if (ng_ether_attach_p != NULL) {
 1006                 CURVNET_SET_QUIET(new_vnet);
 1007                 (*ng_ether_attach_p)(ifp);
 1008                 CURVNET_RESTORE();
 1009         }
 1010 }
 1011 #endif
 1012 
 1013 SYSCTL_DECL(_net_link);
 1014 SYSCTL_NODE(_net_link, IFT_ETHER, ether, CTLFLAG_RW, 0, "Ethernet");
 1015 #if defined(INET) || defined(INET6)
 1016 SYSCTL_VNET_INT(_net_link_ether, OID_AUTO, ipfw, CTLFLAG_RW,
 1017              &VNET_NAME(ether_ipfw), 0, "Pass ether pkts through firewall");
 1018 #endif
 1019 
 1020 #if 0
 1021 /*
 1022  * This is for reference.  We have a table-driven version
 1023  * of the little-endian crc32 generator, which is faster
 1024  * than the double-loop.
 1025  */
 1026 uint32_t
 1027 ether_crc32_le(const uint8_t *buf, size_t len)
 1028 {
 1029         size_t i;
 1030         uint32_t crc;
 1031         int bit;
 1032         uint8_t data;
 1033 
 1034         crc = 0xffffffff;       /* initial value */
 1035 
 1036         for (i = 0; i < len; i++) {
 1037                 for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
 1038                         carry = (crc ^ data) & 1;
 1039                         crc >>= 1;
 1040                         if (carry)
 1041                                 crc = (crc ^ ETHER_CRC_POLY_LE);
 1042                 }
 1043         }
 1044 
 1045         return (crc);
 1046 }
 1047 #else
 1048 uint32_t
 1049 ether_crc32_le(const uint8_t *buf, size_t len)
 1050 {
 1051         static const uint32_t crctab[] = {
 1052                 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
 1053                 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
 1054                 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
 1055                 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
 1056         };
 1057         size_t i;
 1058         uint32_t crc;
 1059 
 1060         crc = 0xffffffff;       /* initial value */
 1061 
 1062         for (i = 0; i < len; i++) {
 1063                 crc ^= buf[i];
 1064                 crc = (crc >> 4) ^ crctab[crc & 0xf];
 1065                 crc = (crc >> 4) ^ crctab[crc & 0xf];
 1066         }
 1067 
 1068         return (crc);
 1069 }
 1070 #endif
 1071 
 1072 uint32_t
 1073 ether_crc32_be(const uint8_t *buf, size_t len)
 1074 {
 1075         size_t i;
 1076         uint32_t crc, carry;
 1077         int bit;
 1078         uint8_t data;
 1079 
 1080         crc = 0xffffffff;       /* initial value */
 1081 
 1082         for (i = 0; i < len; i++) {
 1083                 for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
 1084                         carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
 1085                         crc <<= 1;
 1086                         if (carry)
 1087                                 crc = (crc ^ ETHER_CRC_POLY_BE) | carry;
 1088                 }
 1089         }
 1090 
 1091         return (crc);
 1092 }
 1093 
 1094 int
 1095 ether_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
 1096 {
 1097         struct ifaddr *ifa = (struct ifaddr *) data;
 1098         struct ifreq *ifr = (struct ifreq *) data;
 1099         int error = 0;
 1100 
 1101         switch (command) {
 1102         case SIOCSIFADDR:
 1103                 ifp->if_flags |= IFF_UP;
 1104 
 1105                 switch (ifa->ifa_addr->sa_family) {
 1106 #ifdef INET
 1107                 case AF_INET:
 1108                         ifp->if_init(ifp->if_softc);    /* before arpwhohas */
 1109                         arp_ifinit(ifp, ifa);
 1110                         break;
 1111 #endif
 1112 #ifdef IPX
 1113                 /*
 1114                  * XXX - This code is probably wrong
 1115                  */
 1116                 case AF_IPX:
 1117                         {
 1118                         struct ipx_addr *ina = &(IA_SIPX(ifa)->sipx_addr);
 1119 
 1120                         if (ipx_nullhost(*ina))
 1121                                 ina->x_host =
 1122                                     *(union ipx_host *)
 1123                                     IF_LLADDR(ifp);
 1124                         else {
 1125                                 bcopy((caddr_t) ina->x_host.c_host,
 1126                                       (caddr_t) IF_LLADDR(ifp),
 1127                                       ETHER_ADDR_LEN);
 1128                         }
 1129 
 1130                         /*
 1131                          * Set new address
 1132                          */
 1133                         ifp->if_init(ifp->if_softc);
 1134                         break;
 1135                         }
 1136 #endif
 1137                 default:
 1138                         ifp->if_init(ifp->if_softc);
 1139                         break;
 1140                 }
 1141                 break;
 1142 
 1143         case SIOCGIFADDR:
 1144                 {
 1145                         struct sockaddr *sa;
 1146 
 1147                         sa = (struct sockaddr *) & ifr->ifr_data;
 1148                         bcopy(IF_LLADDR(ifp),
 1149                               (caddr_t) sa->sa_data, ETHER_ADDR_LEN);
 1150                 }
 1151                 break;
 1152 
 1153         case SIOCSIFMTU:
 1154                 /*
 1155                  * Set the interface MTU.
 1156                  */
 1157                 if (ifr->ifr_mtu > ETHERMTU) {
 1158                         error = EINVAL;
 1159                 } else {
 1160                         ifp->if_mtu = ifr->ifr_mtu;
 1161                 }
 1162                 break;
 1163         default:
 1164                 error = EINVAL;                 /* XXX netbsd has ENOTTY??? */
 1165                 break;
 1166         }
 1167         return (error);
 1168 }
 1169 
 1170 static int
 1171 ether_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 1172         struct sockaddr *sa)
 1173 {
 1174         struct sockaddr_dl *sdl;
 1175 #ifdef INET
 1176         struct sockaddr_in *sin;
 1177 #endif
 1178 #ifdef INET6
 1179         struct sockaddr_in6 *sin6;
 1180 #endif
 1181         u_char *e_addr;
 1182 
 1183         switch(sa->sa_family) {
 1184         case AF_LINK:
 1185                 /*
 1186                  * No mapping needed. Just check that it's a valid MC address.
 1187                  */
 1188                 sdl = (struct sockaddr_dl *)sa;
 1189                 e_addr = LLADDR(sdl);
 1190                 if (!ETHER_IS_MULTICAST(e_addr))
 1191                         return EADDRNOTAVAIL;
 1192                 *llsa = 0;
 1193                 return 0;
 1194 
 1195 #ifdef INET
 1196         case AF_INET:
 1197                 sin = (struct sockaddr_in *)sa;
 1198                 if (!IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
 1199                         return EADDRNOTAVAIL;
 1200                 sdl = malloc(sizeof *sdl, M_IFMADDR,
 1201                        M_NOWAIT|M_ZERO);
 1202                 if (sdl == NULL)
 1203                         return ENOMEM;
 1204                 sdl->sdl_len = sizeof *sdl;
 1205                 sdl->sdl_family = AF_LINK;
 1206                 sdl->sdl_index = ifp->if_index;
 1207                 sdl->sdl_type = IFT_ETHER;
 1208                 sdl->sdl_alen = ETHER_ADDR_LEN;
 1209                 e_addr = LLADDR(sdl);
 1210                 ETHER_MAP_IP_MULTICAST(&sin->sin_addr, e_addr);
 1211                 *llsa = (struct sockaddr *)sdl;
 1212                 return 0;
 1213 #endif
 1214 #ifdef INET6
 1215         case AF_INET6:
 1216                 sin6 = (struct sockaddr_in6 *)sa;
 1217                 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
 1218                         /*
 1219                          * An IP6 address of 0 means listen to all
 1220                          * of the Ethernet multicast address used for IP6.
 1221                          * (This is used for multicast routers.)
 1222                          */
 1223                         ifp->if_flags |= IFF_ALLMULTI;
 1224                         *llsa = 0;
 1225                         return 0;
 1226                 }
 1227                 if (!IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 1228                         return EADDRNOTAVAIL;
 1229                 sdl = malloc(sizeof *sdl, M_IFMADDR,
 1230                        M_NOWAIT|M_ZERO);
 1231                 if (sdl == NULL)
 1232                         return (ENOMEM);
 1233                 sdl->sdl_len = sizeof *sdl;
 1234                 sdl->sdl_family = AF_LINK;
 1235                 sdl->sdl_index = ifp->if_index;
 1236                 sdl->sdl_type = IFT_ETHER;
 1237                 sdl->sdl_alen = ETHER_ADDR_LEN;
 1238                 e_addr = LLADDR(sdl);
 1239                 ETHER_MAP_IPV6_MULTICAST(&sin6->sin6_addr, e_addr);
 1240                 *llsa = (struct sockaddr *)sdl;
 1241                 return 0;
 1242 #endif
 1243 
 1244         default:
 1245                 /*
 1246                  * Well, the text isn't quite right, but it's the name
 1247                  * that counts...
 1248                  */
 1249                 return EAFNOSUPPORT;
 1250         }
 1251 }
 1252 
 1253 static void*
 1254 ether_alloc(u_char type, struct ifnet *ifp)
 1255 {
 1256         struct arpcom   *ac;
 1257         
 1258         ac = malloc(sizeof(struct arpcom), M_ARPCOM, M_WAITOK | M_ZERO);
 1259         ac->ac_ifp = ifp;
 1260 
 1261         return (ac);
 1262 }
 1263 
 1264 static void
 1265 ether_free(void *com, u_char type)
 1266 {
 1267 
 1268         free(com, M_ARPCOM);
 1269 }
 1270 
 1271 static int
 1272 ether_modevent(module_t mod, int type, void *data)
 1273 {
 1274 
 1275         switch (type) {
 1276         case MOD_LOAD:
 1277                 if_register_com_alloc(IFT_ETHER, ether_alloc, ether_free);
 1278                 break;
 1279         case MOD_UNLOAD:
 1280                 if_deregister_com_alloc(IFT_ETHER);
 1281                 break;
 1282         default:
 1283                 return EOPNOTSUPP;
 1284         }
 1285 
 1286         return (0);
 1287 }
 1288 
 1289 static moduledata_t ether_mod = {
 1290         "ether",
 1291         ether_modevent,
 1292         0
 1293 };
 1294 
 1295 void
 1296 ether_vlan_mtap(struct bpf_if *bp, struct mbuf *m, void *data, u_int dlen)
 1297 {
 1298         struct ether_vlan_header vlan;
 1299         struct mbuf mv, mb;
 1300 
 1301         KASSERT((m->m_flags & M_VLANTAG) != 0,
 1302             ("%s: vlan information not present", __func__));
 1303         KASSERT(m->m_len >= sizeof(struct ether_header),
 1304             ("%s: mbuf not large enough for header", __func__));
 1305         bcopy(mtod(m, char *), &vlan, sizeof(struct ether_header));
 1306         vlan.evl_proto = vlan.evl_encap_proto;
 1307         vlan.evl_encap_proto = htons(ETHERTYPE_VLAN);
 1308         vlan.evl_tag = htons(m->m_pkthdr.ether_vtag);
 1309         m->m_len -= sizeof(struct ether_header);
 1310         m->m_data += sizeof(struct ether_header);
 1311         /*
 1312          * If a data link has been supplied by the caller, then we will need to
 1313          * re-create a stack allocated mbuf chain with the following structure:
 1314          *
 1315          * (1) mbuf #1 will contain the supplied data link
 1316          * (2) mbuf #2 will contain the vlan header
 1317          * (3) mbuf #3 will contain the original mbuf's packet data
 1318          *
 1319          * Otherwise, submit the packet and vlan header via bpf_mtap2().
 1320          */
 1321         if (data != NULL) {
 1322                 mv.m_next = m;
 1323                 mv.m_data = (caddr_t)&vlan;
 1324                 mv.m_len = sizeof(vlan);
 1325                 mb.m_next = &mv;
 1326                 mb.m_data = data;
 1327                 mb.m_len = dlen;
 1328                 bpf_mtap(bp, &mb);
 1329         } else
 1330                 bpf_mtap2(bp, &vlan, sizeof(vlan), m);
 1331         m->m_len += sizeof(struct ether_header);
 1332         m->m_data -= sizeof(struct ether_header);
 1333 }
 1334 
 1335 struct mbuf *
 1336 ether_vlanencap(struct mbuf *m, uint16_t tag)
 1337 {
 1338         struct ether_vlan_header *evl;
 1339 
 1340         M_PREPEND(m, ETHER_VLAN_ENCAP_LEN, M_DONTWAIT);
 1341         if (m == NULL)
 1342                 return (NULL);
 1343         /* M_PREPEND takes care of m_len, m_pkthdr.len for us */
 1344 
 1345         if (m->m_len < sizeof(*evl)) {
 1346                 m = m_pullup(m, sizeof(*evl));
 1347                 if (m == NULL)
 1348                         return (NULL);
 1349         }
 1350 
 1351         /*
 1352          * Transform the Ethernet header into an Ethernet header
 1353          * with 802.1Q encapsulation.
 1354          */
 1355         evl = mtod(m, struct ether_vlan_header *);
 1356         bcopy((char *)evl + ETHER_VLAN_ENCAP_LEN,
 1357             (char *)evl, ETHER_HDR_LEN - ETHER_TYPE_LEN);
 1358         evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
 1359         evl->evl_tag = htons(tag);
 1360         return (m);
 1361 }
 1362 
 1363 DECLARE_MODULE(ether, ether_mod, SI_SUB_INIT_IF, SI_ORDER_ANY);
 1364 MODULE_VERSION(ether, 1);

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