sys/net/vlan/if_vlan_ether.c

   1 /*
   2  * Copyright 1998 Massachusetts Institute of Technology
   3  *
   4  * Permission to use, copy, modify, and distribute this software and
   5  * its documentation for any purpose and without fee is hereby
   6  * granted, provided that both the above copyright notice and this
   7  * permission notice appear in all copies, that both the above
   8  * copyright notice and this permission notice appear in all
   9  * supporting documentation, and that the name of M.I.T. not be used
  10  * in advertising or publicity pertaining to distribution of the
  11  * software without specific, written prior permission.  M.I.T. makes
  12  * no representations about the suitability of this software for any
  13  * purpose.  It is provided "as is" without express or implied
  14  * warranty.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  17  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  20  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  23  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/sys/net/if_vlan.c,v 1.15.2.13 2003/02/14 22:25:58 fenner Exp $
  30  * $DragonFly: src/sys/net/vlan/if_vlan_ether.c,v 1.3 2008/05/16 13:19:12 sephe Exp $
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/mbuf.h>
  35 #include <sys/serialize.h>
  36
  37 #include <net/bpf.h>
  38 #include <net/ethernet.h>
  39 #include <net/if.h>
  40 #include <net/if_arp.h>
  41 #include <net/ifq_var.h>
  42 #include <net/netmsg.h>
  43
  44 #include <net/vlan/if_vlan_var.h>
  45 #include <net/vlan/if_vlan_ether.h>
  46
  47 void
  48 vlan_start_dispatch(struct netmsg *nmsg)
  49 {
  50         struct netmsg_packet *nmp = (struct netmsg_packet *)nmsg;
  51         struct mbuf *m;
  52         struct ifnet *ifp;
  53         struct altq_pktattr pktattr;
  54
  55         m = nmp->nm_packet;
  56         ifp = nmsg->nm_lmsg.u.ms_resultp;
  57
  58         M_ASSERTPKTHDR(m);
  59         KASSERT(m->m_flags & M_VLANTAG, ("mbuf has not been vlan tagged!\n"));
  60
  61         lwkt_serialize_enter(ifp->if_serializer);
  62
  63         /*
  64          * Make sure that the interface is still UP and RUNNING,
  65          * since interface state may have been changed when the
  66          * mbuf is pending on the msgport.
  67          */
  68         if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
  69             (IFF_UP | IFF_RUNNING)) {
  70                 m_freem(m);
  71                 goto back;
  72         }
  73
  74         /*
  75          * If ALTQ is enabled on the parent interface, do
  76          * classification; the queueing discipline might
  77          * not require classification, but might require
  78          * the address family/header pointer in the pktattr.
  79          */
  80         if (ifq_is_enabled(&ifp->if_snd))
  81                 altq_etherclassify(&ifp->if_snd, m, &pktattr);
  82
  83         /*
  84          * If underlying interface can do VLAN tag insertion itself,
  85          * just pass the packet along.
  86          */
  87         if ((ifp->if_capenable & IFCAP_VLAN_HWTAGGING) == 0) {
  88                 uint16_t vlantag = m->m_pkthdr.ether_vlantag;
  89                 struct ether_vlan_header *evl;
  90
  91                 M_PREPEND(m, EVL_ENCAPLEN, MB_DONTWAIT);
  92                 if (m == NULL) {
  93                         if_printf(ifp, "vlan%u M_PREPEND failed", vlantag);
  94                         goto back;
  95                 }
  96                 /* M_PREPEND takes care of m_len, m_pkthdr.len for us */
  97
  98                 m = m_pullup(m, ETHER_HDR_LEN + EVL_ENCAPLEN);
  99                 if (m == NULL) {
 100                         if_printf(ifp, "vlan%u m_pullup failed", vlantag);
 101                         goto back;
 102                 }
 103
 104                 /*
 105                  * Transform the Ethernet header into an Ethernet header
 106                  * with 802.1Q encapsulation.
 107                  */
 108                 bcopy(mtod(m, char *) + EVL_ENCAPLEN, mtod(m, char *),
 109                       sizeof(struct ether_header));
 110                 evl = mtod(m, struct ether_vlan_header *);
 111                 evl->evl_proto = evl->evl_encap_proto;
 112                 evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
 113                 evl->evl_tag = htons(vlantag);
 114 #ifdef DEBUG
 115                 kprintf("vlan_start: %*D\n", sizeof *evl,
 116                         (unsigned char *)evl, ":");
 117 #endif
 118                 /* Hardware does not need to setup vlan tagging */
 119                 m->m_flags &= ~M_VLANTAG;
 120         }
 121         ifq_handoff(ifp, m, &pktattr);
 122 back:
 123         lwkt_serialize_exit(ifp->if_serializer);
 124 }
 125
 126 void
 127 vlan_ether_ptap(struct bpf_if *bp, struct mbuf *m, uint16_t vlantag)
 128 {
 129         const struct ether_header *eh;
 130         struct ether_vlan_header evh;
 131
 132         KASSERT(m->m_len >= ETHER_HDR_LEN,
 133                 ("ether header is not contiguous!\n"));
 134
 135         eh = mtod(m, const struct ether_header *);
 136         m_adj(m, ETHER_HDR_LEN);
 137
 138         bcopy(eh, &evh, 2 * ETHER_ADDR_LEN);
 139         evh.evl_encap_proto = htons(ETHERTYPE_VLAN);
 140         evh.evl_tag = htons(vlantag);
 141         evh.evl_proto = eh->ether_type;
 142         bpf_ptap(bp, m, &evh, ETHER_HDR_LEN + EVL_ENCAPLEN);
 143
 144         /* XXX assumes data was left intact */
 145         M_PREPEND(m, ETHER_HDR_LEN, MB_WAIT);
 146 }
 147
 148 void
 149 vlan_ether_decap(struct mbuf **m0)
 150 {
 151         struct mbuf *m = *m0;
 152         struct ether_vlan_header *evh;
 153
 154         KKASSERT((m->m_flags & M_VLANTAG) == 0);
 155
 156         if (m->m_len < sizeof(*evh)) {
 157                 /* Error in the caller */
 158                 m_freem(m);
 159                 *m0 = NULL;
 160                 return;
 161         }
 162         evh = mtod(m, struct ether_vlan_header *);
 163
 164         m->m_pkthdr.ether_vlantag = ntohs(evh->evl_tag);
 165         m->m_flags |= M_VLANTAG;
 166
 167         bcopy((uint8_t *)evh, (uint8_t *)evh + EVL_ENCAPLEN,
 168               2 * ETHER_ADDR_LEN);
 169         m_adj(m, EVL_ENCAPLEN);
 170         *m0 = m;
 171 }