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

     /*
      * Copyright 1998 Massachusetts Institute of Technology
      *
      * Permission to use, copy, modify, and distribute this software and
      * its documentation for any purpose and without fee is hereby
      * granted, provided that both the above copyright notice and this
      * permission notice appear in all copies, that both the above
      * copyright notice and this permission notice appear in all
      * supporting documentation, and that the name of M.I.T. not be used
     * in advertising or publicity pertaining to distribution of the
     * software without specific, written prior permission.  M.I.T. makes
     * no representations about the suitability of this software for any
     * purpose.  It is provided "as is" without express or implied
     * warranty.
     * 
     * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
     * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
     * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
     * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
     * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    /*
     * if_vlan.c - pseudo-device driver for IEEE 802.1Q virtual LANs.
     * Might be extended some day to also handle IEEE 802.1p priority
     * tagging.  This is sort of sneaky in the implementation, since
     * we need to pretend to be enough of an Ethernet implementation
     * to make arp work.  The way we do this is by telling everyone
     * that we are an Ethernet, and then catch the packets that
     * ether_output() left on our output queue queue when it calls
     * if_start(), rewrite them for use by the real outgoing interface,
     * and ask it to send them.
     *
     *
     * XXX It's incorrect to assume that we must always kludge up
     * headers on the physical device's behalf: some devices support
     * VLAN tag insersion and extraction in firmware. For these cases,
     * one can change the behavior of the vlan interface by setting
     * the LINK0 flag on it (that is setting the vlan interface's LINK0
     * flag, _not_ the parent's LINK0 flag; we try to leave the parent
     * alone). If the interface as the LINK0 flag set, then it will
     * not modify the ethernet header on output because the parent
     * can do that for itself. On input, the parent can call vlan_input_tag()
     * directly in order to supply us with an incoming mbuf and the vlan
     * tag value that goes with it.
     */
    
    #include "vlan.h"
    #if NVLAN > 0
    #include "opt_inet.h"
    #include "bpfilter.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/queue.h>
    #include <sys/socket.h>
    #include <sys/sockio.h>
    #include <sys/sysctl.h>
    #include <sys/systm.h>
    
    #if NBPFILTER > 0
    #include <net/bpf.h>
    #endif
    #include <net/ethernet.h>
    #include <net/if.h>
    #include <net/if_arp.h>
    #include <net/if_dl.h>
    #include <net/if_types.h>
    #include <net/if_vlan_var.h>
    
    #ifdef INET
    #include <netinet/in.h>
    #include <netinet/if_ether.h>
    #endif
    
    SYSCTL_NODE(_net_link, IFT_8021_VLAN, vlan, CTLFLAG_RW, 0, "IEEE 802.1Q VLAN");
    SYSCTL_NODE(_net_link_vlan, PF_LINK, link, CTLFLAG_RW, 0, "for consistency");
    
    u_int   vlan_proto = ETHERTYPE_VLAN;
    SYSCTL_INT(_net_link_vlan_link, VLANCTL_PROTO, proto, CTLFLAG_RW, &vlan_proto,
               0, "Ethernet protocol used for VLAN encapsulation");
    
    static  struct ifvlan ifv_softc[NVLAN];
    
    static  void vlan_start(struct ifnet *ifp);
    static  void vlan_ifinit(void *foo);
    static  int vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr);
    static  int vlan_setmulti(struct ifnet *ifp);
   static  int vlan_unconfig(struct ifnet *ifp);
   static  int vlan_config(struct ifvlan *ifv, struct ifnet *p);
   
   /*
    * Program our multicast filter. What we're actually doing is
    * programming the multicast filter of the parent. This has the
    * side effect of causing the parent interface to receive multicast
    * traffic that it doesn't really want, which ends up being discarded
    * later by the upper protocol layers. Unfortunately, there's no way
    * to avoid this: there really is only one physical interface.
    */
   static int vlan_setmulti(struct ifnet *ifp)
   {
           struct ifnet            *ifp_p;
           struct ifmultiaddr      *ifma, *rifma = NULL;
           struct ifvlan           *sc;
           struct vlan_mc_entry    *mc = NULL;
           struct sockaddr_dl      sdl;
           int                     error;
   
           /* Find the parent. */
           sc = ifp->if_softc;
           ifp_p = sc->ifv_p;
   
           sdl.sdl_len = ETHER_ADDR_LEN;
           sdl.sdl_family = AF_LINK;
   
           /* First, remove any existing filter entries. */
           while(sc->vlan_mc_listhead.slh_first != NULL) {
                   mc = sc->vlan_mc_listhead.slh_first;
                   bcopy((char *)&mc->mc_addr, LLADDR(&sdl), ETHER_ADDR_LEN);
                   error = if_delmulti(ifp_p, (struct sockaddr *)&sdl);
                   if (error)
                           return(error);
                   SLIST_REMOVE_HEAD(&sc->vlan_mc_listhead, mc_entries);
                   free(mc, M_DEVBUF);
           }
   
           /* Now program new ones. */
           for (ifma = ifp->if_multiaddrs.lh_first;
               ifma != NULL;ifma = ifma->ifma_link.le_next) {
                   if (ifma->ifma_addr->sa_family != AF_LINK)
                           continue;
                   mc = malloc(sizeof(struct vlan_mc_entry), M_DEVBUF, M_NOWAIT);
                   bcopy(LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
                       (char *)&mc->mc_addr, ETHER_ADDR_LEN);
                   SLIST_INSERT_HEAD(&sc->vlan_mc_listhead, mc, mc_entries);
                   error = if_addmulti(ifp_p, (struct sockaddr *)&sdl, &rifma);
                   if (error)
                           return(error);
           }
   
           return(0);
   }
   
   static void
   vlaninit(void *dummy)
   {
           int i;
   
           for (i = 0; i < NVLAN; i++) {
                   struct ifnet *ifp = &ifv_softc[i].ifv_if;
   
                   ifp->if_softc = &ifv_softc[i];
                   ifp->if_name = "vlan";
                   ifp->if_unit = i;
                   /* NB: flags are not set here */
                   ifp->if_linkmib = &ifv_softc[i].ifv_mib;
                   ifp->if_linkmiblen = sizeof ifv_softc[i].ifv_mib;
                   /* NB: mtu is not set here */
   
                   ifp->if_init = vlan_ifinit;
                   ifp->if_start = vlan_start;
                   ifp->if_ioctl = vlan_ioctl;
                   ifp->if_output = ether_output;
                   ifp->if_snd.ifq_maxlen = ifqmaxlen;
                   if_attach(ifp);
                   ether_ifattach(ifp);
   #if NBPFILTER > 0
                   bpfattach(ifp, DLT_EN10MB, sizeof(struct ether_header));
   #endif
                   /* Now undo some of the damage... */
                   ifp->if_data.ifi_type = IFT_8021_VLAN;
                   ifp->if_data.ifi_hdrlen = EVL_ENCAPLEN;
                   ifp->if_resolvemulti = 0;
           }
   }
   PSEUDO_SET(vlaninit, if_vlan);
   
   static void
   vlan_ifinit(void *foo)
   {
           return;
   }
   
   static void
   vlan_start(struct ifnet *ifp)
   {
           struct ifvlan *ifv;
           struct ifnet *p;
           struct ether_vlan_header *evl;
           struct mbuf *m;
   
           ifv = ifp->if_softc;
           p = ifv->ifv_p;
   
           ifp->if_flags |= IFF_OACTIVE;
           for (;;) {
                   IF_DEQUEUE(&ifp->if_snd, m);
                   if (m == 0)
                           break;
   #if NBPFILTER > 0
                   if (ifp->if_bpf)
                           bpf_mtap(ifp, m);
   #endif /* NBPFILTER > 0 */
   
                   /*
                    * If the LINK0 flag is set, it means the underlying interface
                    * can do VLAN tag insertion itself and doesn't require us to
                    * create a special header for it. In this case, we just pass
                    * the packet along. However, we need some way to tell the
                    * interface where the packet came from so that it knows how
                    * to find the VLAN tag to use, so we set the rcvif in the
                    * mbuf header to our ifnet.
                    *
                    * Note: we also set the M_PROTO1 flag in the mbuf to let
                    * the parent driver know that the rcvif pointer is really
                    * valid. We need to do this because sometimes mbufs will
                    * be allocated by other parts of the system that contain
                    * garbage in the rcvif pointer. Using the M_PROTO1 flag
                    * lets the driver perform a proper sanity check and avoid
                    * following potentially bogus rcvif pointers off into
                    * never-never land.
                    */
                   if (ifp->if_flags & IFF_LINK0) {
                           m->m_pkthdr.rcvif = ifp;
                           m->m_flags |= M_PROTO1;
                   } else {
                           M_PREPEND(m, EVL_ENCAPLEN, M_DONTWAIT);
                           if (m == 0)
                                   continue;
                           /* M_PREPEND takes care of m_len, m_pkthdr.len for us */
   
                           /*
                            * Transform the Ethernet header into an Ethernet header
                            * with 802.1Q encapsulation.
                            */
                           bcopy(mtod(m, char *) + EVL_ENCAPLEN, mtod(m, char *),
                                 sizeof(struct ether_header));
                           evl = mtod(m, struct ether_vlan_header *);
                           evl->evl_proto = evl->evl_encap_proto;
                           evl->evl_encap_proto = htons(vlan_proto);
                           evl->evl_tag = htons(ifv->ifv_tag);
   #ifdef DEBUG
                           printf("vlan_start: %*D\n", sizeof *evl,
                               (char *)evl, ":");
   #endif
                   }
   
                   /*
                    * Send it, precisely as ether_output() would have.
                    * We are already running at splimp.
                    */
                   if (IF_QFULL(&p->if_snd)) {
                           IF_DROP(&p->if_snd);
                                   /* XXX stats */
                           ifp->if_oerrors++;
                           m_freem(m);
                           continue;
                   }
                   IF_ENQUEUE(&p->if_snd, m);
                   if ((p->if_flags & IFF_OACTIVE) == 0) {
                           p->if_start(p);
                           ifp->if_opackets++;
                   }
           }
           ifp->if_flags &= ~IFF_OACTIVE;
   }
   
   int
   vlan_input_tag(struct ether_header *eh, struct mbuf *m, u_int16_t t)
   {
           int i;
           struct ifvlan *ifv;
   
           for (i = 0; i < NVLAN; i++) {
                   ifv = &ifv_softc[i];
                   if (ifv->ifv_tag == t)
                           break;
           }
   
           if (i >= NVLAN || (ifv->ifv_if.if_flags & IFF_UP) == 0) {
                   m_free(m);
                   return -1;      /* So the parent can take note */
           }
   
           /*
            * Having found a valid vlan interface corresponding to
            * the given source interface and vlan tag, run the
            * the real packet through ethert_input().
            */
           m->m_pkthdr.rcvif = &ifv->ifv_if;
   
           if (ifv->ifv_if.if_bpf) {
                   /*
                    * Do the usual BPF fakery.  Note that we don't support
                    * promiscuous mode here, since it would require the
                    * drivers to know about VLANs and we're not ready for
                    * that yet.
                    */
                   struct mbuf m0;
                   m0.m_next = m;
                   m0.m_len = sizeof(struct ether_header);
                   m0.m_data = (char *)eh;
                   bpf_mtap(&ifv->ifv_if, &m0);
           }
           ifv->ifv_if.if_ipackets++;
           ether_input(&ifv->ifv_if, eh, m);
           return 0;
   }
   
   int
   vlan_input(struct ether_header *eh, struct mbuf *m)
   {
           int i;
           struct ifvlan *ifv;
   
           for (i = 0; i < NVLAN; i++) {
                   ifv = &ifv_softc[i];
                   if (m->m_pkthdr.rcvif == ifv->ifv_p
                       && (EVL_VLANOFTAG(ntohs(*mtod(m, u_int16_t *)))
                           == ifv->ifv_tag))
                           break;
           }
   
           if (i >= NVLAN || (ifv->ifv_if.if_flags & IFF_UP) == 0) {
                   m_freem(m);
                   return -1;      /* so ether_input can take note */
           }
   
           /*
            * Having found a valid vlan interface corresponding to
            * the given source interface and vlan tag, remove the
            * encapsulation, and run the real packet through
            * ether_input() a second time (it had better be
            * reentrant!).
            */
           m->m_pkthdr.rcvif = &ifv->ifv_if;
           eh->ether_type = mtod(m, u_int16_t *)[1];
           m->m_data += EVL_ENCAPLEN;
           m->m_len -= EVL_ENCAPLEN;
           m->m_pkthdr.len -= EVL_ENCAPLEN;
   
   #if NBPFILTER > 0
           if (ifv->ifv_if.if_bpf) {
                   /*
                    * Do the usual BPF fakery.  Note that we don't support
                    * promiscuous mode here, since it would require the
                    * drivers to know about VLANs and we're not ready for
                    * that yet.
                    */
                   struct mbuf m0;
                   m0.m_next = m;
                   m0.m_len = sizeof(struct ether_header);
                   m0.m_data = (char *)eh;
                   bpf_mtap(&ifv->ifv_if, &m0);
           }
   #endif
           ether_input(&ifv->ifv_if, eh, m);
           return 0;
   }
   
   static int
   vlan_config(struct ifvlan *ifv, struct ifnet *p)
   {
           struct ifaddr *ifa1, *ifa2;
           struct sockaddr_dl *sdl1, *sdl2;
   
           if (p->if_data.ifi_type != IFT_ETHER)
                   return EPROTONOSUPPORT;
           if (ifv->ifv_p)
                   return EBUSY;
           ifv->ifv_p = p;
           if (p->if_data.ifi_hdrlen == sizeof(struct ether_vlan_header))
                   ifv->ifv_if.if_mtu = p->if_mtu;
           else
                   ifv->ifv_if.if_mtu = p->if_data.ifi_mtu - EVL_ENCAPLEN;
   
           /*
            * Preserve the state of the LINK0 flag for ourselves.
            */
           ifv->ifv_if.if_flags = (p->if_flags & ~(IFF_LINK0));
   
           /*
            * Set up our ``Ethernet address'' to reflect the underlying
            * physical interface's.
            */
           ifa1 = ifnet_addrs[ifv->ifv_if.if_index - 1];
           ifa2 = ifnet_addrs[p->if_index - 1];
           sdl1 = (struct sockaddr_dl *)ifa1->ifa_addr;
           sdl2 = (struct sockaddr_dl *)ifa2->ifa_addr;
           sdl1->sdl_type = IFT_ETHER;
           sdl1->sdl_alen = ETHER_ADDR_LEN;
           bcopy(LLADDR(sdl2), LLADDR(sdl1), ETHER_ADDR_LEN);
           bcopy(LLADDR(sdl2), ifv->ifv_ac.ac_enaddr, ETHER_ADDR_LEN);
           return 0;
   }
   
   static int
   vlan_unconfig(struct ifnet *ifp)
   {
           struct ifaddr *ifa;
           struct sockaddr_dl *sdl;
           struct vlan_mc_entry *mc;
           struct ifvlan *ifv;
           struct ifnet *p;
           int error;
   
           ifv = ifp->if_softc;
           p = ifv->ifv_p;
   
           /*
            * Since the interface is being unconfigured, we need to
            * empty the list of multicast groups that we may have joined
            * while we were alive and remove them from the parent's list
            * as well.
            */
           while(ifv->vlan_mc_listhead.slh_first != NULL) {
                   struct sockaddr_dl      sdl;
   
                   sdl.sdl_len = ETHER_ADDR_LEN;
                   sdl.sdl_family = AF_LINK;
                   mc = ifv->vlan_mc_listhead.slh_first;
                   bcopy((char *)&mc->mc_addr, LLADDR(&sdl), ETHER_ADDR_LEN);
                   error = if_delmulti(p, (struct sockaddr *)&sdl);
                   error = if_delmulti(ifp, (struct sockaddr *)&sdl);
                   if (error)
                           return(error);
                   SLIST_REMOVE_HEAD(&ifv->vlan_mc_listhead, mc_entries);
                   free(mc, M_DEVBUF);
           }
   
           /* Disconnect from parent. */
           ifv->ifv_p = NULL;
           ifv->ifv_if.if_mtu = ETHERMTU;
   
           /* Clear our MAC address. */
           ifa = ifnet_addrs[ifv->ifv_if.if_index - 1];
           sdl = (struct sockaddr_dl *)ifa->ifa_addr;
           sdl->sdl_type = IFT_ETHER;
           sdl->sdl_alen = ETHER_ADDR_LEN;
           bzero(LLADDR(sdl), ETHER_ADDR_LEN);
           bzero(ifv->ifv_ac.ac_enaddr, ETHER_ADDR_LEN);
   
           return 0;
   }
   
   static int
   vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
   {
           struct ifaddr *ifa;
           struct ifnet *p;
           struct ifreq *ifr;
           struct ifvlan *ifv;
           struct vlanreq vlr;
           int error = 0;
   
           ifr = (struct ifreq *)data;
           ifa = (struct ifaddr *)data;
           ifv = ifp->if_softc;
   
           switch (cmd) {
           case SIOCSIFADDR:
                   ifp->if_flags |= IFF_UP;
   
                   switch (ifa->ifa_addr->sa_family) {
   #ifdef INET
                   case AF_INET:
                           arp_ifinit(&ifv->ifv_ac, ifa);
                           break;
   #endif
                   default:
                           break;
                   }
                   break;
   
           case SIOCGIFADDR:
                   {
                           struct sockaddr *sa;
   
                           sa = (struct sockaddr *) &ifr->ifr_data;
                           bcopy(((struct arpcom *)ifp->if_softc)->ac_enaddr,
                                 (caddr_t) sa->sa_data, ETHER_ADDR_LEN);
                   }
                   break;
   
           case SIOCSIFMTU:
                   /*
                    * Set the interface MTU.
                    * This is bogus.  The underlying interface might support
                    * jumbo frames.
                    */
                   if (ifr->ifr_mtu > ETHERMTU) {
                           error = EINVAL;
                   } else {
                           ifp->if_mtu = ifr->ifr_mtu;
                   }
                   break;
   
           case SIOCSETVLAN:
                   error = copyin(ifr->ifr_data, &vlr, sizeof vlr);
                   if (error)
                           break;
                   if (vlr.vlr_parent[0] == '\0') {
                           vlan_unconfig(ifp);
                           ifv->ifv_p = 0;
                           if_down(ifp);
                           ifp->if_flags &= ~(IFF_UP|IFF_RUNNING);
                           break;
                   }
                   p = ifunit(vlr.vlr_parent);
                   if (p == 0) {
                           error = ENOENT;
                           break;
                   }
                   error = vlan_config(ifv, p);
                   if (error)
                           break;
                   ifv->ifv_tag = vlr.vlr_tag;
                   ifp->if_flags |= IFF_RUNNING;
                   break;
                   
           case SIOCGETVLAN:
                   bzero(&vlr, sizeof vlr);
                   if (ifv->ifv_p) {
                           snprintf(vlr.vlr_parent, sizeof(vlr.vlr_parent),
                               "%s%d", ifv->ifv_p->if_name, ifv->ifv_p->if_unit);
                           vlr.vlr_tag = ifv->ifv_tag;
                   }
                   error = copyout(&vlr, ifr->ifr_data, sizeof vlr);
                   break;
                   
           case SIOCSIFFLAGS:
                   /*
                    * We don't support all-multicast or promiscuous modes
                    * right now because it would require help from the
                    * underlying drivers, which hasn't been implemented.
                    */
                   if (ifr->ifr_flags & (IFF_PROMISC|IFF_ALLMULTI)) {
                           ifp->if_flags &= ~(IFF_PROMISC|IFF_ALLMULTI);
                           error = EINVAL;
                   }
                   break;
           case SIOCADDMULTI:
           case SIOCDELMULTI:
                   error = vlan_setmulti(ifp);
                   break;
           default:
                   error = EINVAL;
           }
           return error;
   }
   
   #endif /* NVLAN > 0 */

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