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  */
  31
  32 #include <sys/param.h>
  33 #include <sys/mbuf.h>
  34 #include <sys/serialize.h>
  35
  36 #include <net/bpf.h>
  37 #include <net/ethernet.h>
  38 #include <net/if.h>
  39 #include <net/if_arp.h>
  40 #include <net/ifq_var.h>
  41 #include <net/netmsg.h>
  42
  43 #include <net/vlan/if_vlan_var.h>
  44 #include <net/vlan/if_vlan_ether.h>
  45
  46 void
  47 vlan_start_dispatch(netmsg_t msg)
  48 {
  49         struct netmsg_packet *nmp = &msg->packet;
  50         struct mbuf *m;
  51         struct ifnet *ifp;
  52         struct altq_pktattr pktattr;
  53 #ifdef DEBUG
  54         char hexstr[HEX_NCPYLEN(sizeof(struct ether_vlan_header))];
  55 #endif
  56         m = nmp->nm_packet;
  57         ifp = msg->lmsg.u.ms_resultp;
  58
  59         M_ASSERTPKTHDR(m);
  60         KASSERT(m->m_flags & M_VLANTAG, ("mbuf has not been vlan tagged!"));
  61
  62         /*
  63          * If ALTQ is enabled on the parent interface, do
  64          * classification; the queueing discipline might
  65          * not require classification, but might require
  66          * the address family/header pointer in the pktattr.
  67          */
  68         if (ifq_is_enabled(&ifp->if_snd))
  69                 altq_etherclassify(&ifp->if_snd, m, &pktattr);
  70
  71         /*
  72          * If underlying interface can do VLAN tag insertion itself,
  73          * just pass the packet along.
  74          */
  75         if ((ifp->if_capenable & IFCAP_VLAN_HWTAGGING) == 0) {
  76                 uint16_t vlantag = m->m_pkthdr.ether_vlantag;
  77                 struct ether_vlan_header *evl;
  78
  79                 M_PREPEND(m, EVL_ENCAPLEN, M_NOWAIT);
  80                 if (m == NULL) {
  81                         if_printf(ifp, "vlan%u M_PREPEND failed", vlantag);
  82                         return;
  83                 }
  84                 /* M_PREPEND takes care of m_len, m_pkthdr.len for us */
  85
  86                 m = m_pullup(m, ETHER_HDR_LEN + EVL_ENCAPLEN);
  87                 if (m == NULL) {
  88                         if_printf(ifp, "vlan%u m_pullup failed", vlantag);
  89                         return;
  90                 }
  91                 m->m_pkthdr.csum_lhlen = sizeof(struct ether_vlan_header);
  92
  93                 /*
  94                  * Transform the Ethernet header into an Ethernet header
  95                  * with 802.1Q encapsulation.
  96                  */
  97                 bcopy(mtod(m, char *) + EVL_ENCAPLEN, mtod(m, char *),
  98                       sizeof(struct ether_header));
  99                 evl = mtod(m, struct ether_vlan_header *);
 100                 evl->evl_proto = evl->evl_encap_proto;
 101                 evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
 102                 evl->evl_tag = htons(vlantag);
 103 #ifdef DEBUG
 104                 kprintf("vlan_start: %s\n", hexncpy((u_char *)evl, sizeof(*evl),
 105                         hexstr, HEX_NCPYLEN(sizeof(*evl)), ":"));
 106 #endif
 107                 /* Hardware does not need to setup vlan tagging */
 108                 m->m_flags &= ~M_VLANTAG;
 109         }
 110         ifq_dispatch(ifp, m, &pktattr);
 111 }
 112
 113 void
 114 vlan_ether_ptap(struct bpf_if *bp, struct mbuf *m, uint16_t vlantag)
 115 {
 116         const struct ether_header *eh;
 117         struct ether_vlan_header evh;
 118
 119         KASSERT(m->m_len >= ETHER_HDR_LEN,
 120                 ("ether header is not contiguous!"));
 121
 122         eh = mtod(m, const struct ether_header *);
 123         m_adj(m, ETHER_HDR_LEN);
 124
 125         bcopy(eh, &evh, 2 * ETHER_ADDR_LEN);
 126         evh.evl_encap_proto = htons(ETHERTYPE_VLAN);
 127         evh.evl_tag = htons(vlantag);
 128         evh.evl_proto = eh->ether_type;
 129         bpf_ptap(bp, m, &evh, ETHER_HDR_LEN + EVL_ENCAPLEN);
 130
 131         /* XXX assumes data was left intact */
 132         M_PREPEND(m, ETHER_HDR_LEN, M_WAITOK);
 133 }
 134
 135 void
 136 vlan_ether_decap(struct mbuf **m0)
 137 {
 138         struct mbuf *m = *m0;
 139         struct ether_vlan_header *evh;
 140
 141         KKASSERT((m->m_flags & M_VLANTAG) == 0);
 142
 143         if (m->m_len < sizeof(*evh)) {
 144                 /* Error in the caller */
 145                 m_freem(m);
 146                 *m0 = NULL;
 147                 return;
 148         }
 149         evh = mtod(m, struct ether_vlan_header *);
 150
 151         m->m_pkthdr.ether_vlantag = ntohs(evh->evl_tag);
 152         m->m_flags |= M_VLANTAG;
 153
 154         bcopy((uint8_t *)evh, (uint8_t *)evh + EVL_ENCAPLEN,
 155               2 * ETHER_ADDR_LEN);
 156         m_adj(m, EVL_ENCAPLEN);
 157         *m0 = m;
 158 }