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/mbuf.h>
  35 #include <sys/systm.h>          /* ncpus2_mask */
  36 #include <sys/types.h>
  37
  38 #include <net/netisr.h>
  39
  40 #include <netinet/in_var.h>
  41
  42 #include <netproto/mpls/mpls.h>
  43 #include <netproto/mpls/mpls_var.h>
  44
  45 extern struct thread netisr_cpu[];
  46
  47 static __inline int
  48 MPLSP_MPORT_HASH(mpls_label_t label, u_short if_index)
  49 {
  50         /* Use low order byte (demux up to 256 cpus) */
  51         KASSERT(ncpus2 < 256, ("need different hash function"));  /* XXX */
  52 #if BYTE_ORDER == LITTLE_ENDIAN
  53         label &= 0x00ff0000;
  54         label = label >> 16;
  55 #endif
  56         return ((label ^ if_index) & ncpus2_mask);
  57 }
  58
  59 boolean_t
  60 mpls_lengthcheck(struct mbuf **mp)
  61 {
  62         struct mbuf *m = *mp;
  63
  64         /* The packet must be at least the size of an MPLS header. */
  65         if (m->m_pkthdr.len < sizeof(struct mpls)) {
  66                 mplsstat.mplss_tooshort++;
  67                 m_free(m);
  68                 return FALSE;
  69         }
  70
  71         /* The MPLS header must reside completely in the first mbuf. */
  72         if (m->m_len < sizeof(struct mpls)) {
  73                 m = m_pullup(m, sizeof(struct mpls));
  74                 if (m == NULL) {
  75                         mplsstat.mplss_toosmall++;
  76                         return FALSE;
  77                 }
  78         }
  79
  80         *mp = m;
  81         return TRUE;
  82 }
  83
  84 struct lwkt_port *
  85 mpls_mport(struct mbuf **mp)
  86 {
  87         struct mbuf *m = *mp;
  88         struct mpls *mpls;
  89         mpls_label_t label;
  90         struct ifnet *ifp;
  91         int cpu;
  92         lwkt_port_t port;
  93
  94         if (!mpls_lengthcheck(mp)) {
  95                 *mp = NULL;
  96                 return (NULL);
  97         }
  98
  99         mpls = mtod(m, struct mpls *);
 100
 101         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 102         ifp = m->m_pkthdr.rcvif;
 103         cpu = MPLSP_MPORT_HASH(label, ifp->if_index);
 104         port = &netisr_cpu[cpu].td_msgport;
 105
 106         return (port);
 107 }
 108