sys/netproto/mpls/mpls_demux.c

   1 /*
   2  * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   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
  12  *    the documentation and/or other materials provided with the
  13  *    distribution.
  14  * 3. Neither the name of The DragonFly Project nor the names of its
  15  *    contributors may be used to endorse or promote products derived
  16  *    from this software without specific, prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  * $DragonFly: src/sys/netproto/mpls/mpls_demux.c,v 1.2 2008/08/05 15:11:32 nant Exp $
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/mbuf.h>
  36
  37 #include <net/netisr.h>
  38 #include <netinet/in_var.h>
  39
  40 #include <netproto/mpls/mpls.h>
  41 #include <netproto/mpls/mpls_var.h>
  42
  43 static __inline int
  44 MPLSP_MPORT_HASH(mpls_label_t label, u_short if_index)
  45 {
  46         /* Use low order byte (demux up to 256 cpus) */
  47         KASSERT(netisr_ncpus <= 256, ("need different hash function"));  /* XXX */
  48 #if BYTE_ORDER == LITTLE_ENDIAN
  49         label &= 0x00ff0000;
  50         label = label >> 16;
  51 #endif
  52         return ((label ^ if_index) % netisr_ncpus);
  53 }
  54
  55 static void
  56 mpls_lengthcheck(struct mbuf **mp, int hoff)
  57 {
  58         struct mbuf *m = *mp;
  59         int hlen = hoff + sizeof(struct mpls);
  60
  61         /* The packet must be at least the size of an MPLS header. */
  62         if (m->m_pkthdr.len < hlen) {
  63                 mplsstat.mplss_tooshort++;
  64                 m_free(m);
  65                 *mp = NULL;
  66                 return;
  67         }
  68
  69         /* The MPLS header must reside completely in the first mbuf. */
  70         if (m->m_len < hlen) {
  71                 m = m_pullup(m, hlen);
  72                 if (m == NULL) {
  73                         mplsstat.mplss_toosmall++;
  74                         *mp = NULL;
  75                         return;
  76                 }
  77         }
  78         *mp = m;
  79 }
  80
  81 void
  82 mpls_hashfn(struct mbuf **mp, int hoff)
  83 {
  84         struct mbuf *m = *mp;
  85         struct mpls *mpls;
  86         mpls_label_t label;
  87         struct ifnet *ifp;
  88
  89         mpls_lengthcheck(mp, hoff);
  90         if ((m = *mp) == NULL)
  91                 return;
  92
  93         mpls = mtodoff(m, struct mpls *, hoff);
  94
  95         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
  96         ifp = m->m_pkthdr.rcvif;
  97         m_sethash(m, MPLSP_MPORT_HASH(label, ifp->if_index));
  98 }