sys/netproto/mpls/mpls_input.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_input.c,v 1.4 2008/09/24 14:26:39 sephe Exp $
  32  */
  33
  34 #include <sys/globaldata.h>
  35 #include <sys/kernel.h>
  36 #include <sys/mbuf.h>
  37 #include <sys/param.h>
  38 #include <sys/sysctl.h>
  39 #include <sys/systm.h>
  40
  41 #include <net/if_var.h>
  42 #include <net/netisr.h>
  43 #include <net/route.h>
  44
  45 #include <netproto/mpls/mpls.h>
  46 #include <netproto/mpls/mpls_var.h>
  47
  48 struct mpls_stats       mplsstats_percpu[MAXCPU];
  49 struct route            mplsforward_rt[MAXCPU];
  50
  51 int mplsforwarding = 1;
  52 /*
  53 SYSCTL_INT(_net_mpls, OID_AUTO, forwarding, CTLFLAG_RW,
  54     &mplsforwarding, 0, "Enable MPLS forwarding between interfaces");
  55 */
  56
  57 static void     mpls_input_handler(struct netmsg *);
  58 static void     mpls_forward(struct mbuf *);
  59
  60 void
  61 mpls_init(void)
  62 {
  63 #ifdef SMP
  64         int cpu;
  65 #endif
  66
  67         /*
  68          * Initialize MPLS statistics counters for each CPU.
  69          *
  70          */
  71 #ifdef SMP
  72         for (cpu = 0; cpu < ncpus; ++cpu) {
  73                 bzero(&mplsstats_percpu[cpu], sizeof(struct mpls_stats));
  74         }
  75 #else
  76         bzero(&mplsstat, sizeof(struct mpls_stats));
  77 #endif
  78
  79         netisr_register(NETISR_MPLS, mpls_mport, pktinfo_portfn_notsupp,
  80                         mpls_input_handler, NETISR_FLAG_NOTMPSAFE);
  81 }
  82
  83 static void
  84 mpls_input_handler(struct netmsg *msg0)
  85 {
  86         struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet;
  87
  88         mpls_input(m);
  89 }
  90
  91 void
  92 mpls_input(struct mbuf *m)
  93 {
  94         struct mpls *mpls = NULL;
  95         mpls_label_t label;
  96
  97         M_ASSERTPKTHDR(m);
  98
  99         mplsstat.mplss_total++;
 100
 101         /* length checks already performed at mpls_demux() */
 102         KASSERT(m->m_pkthdr.len >= sizeof(struct mpls),
 103             ("mpls_input: mpls header too small"));
 104
 105 again:
 106         if (m->m_len < sizeof(struct mpls)) {
 107                 m = m_pullup(m, sizeof(struct mpls));
 108                 if (m == NULL) {
 109                         mplsstat.mplss_toosmall++;
 110                         return;
 111                 }
 112         }
 113
 114         mpls = mtod(m, struct mpls*);
 115         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 116         switch (label) {
 117         case 0:
 118                 /*
 119                  * Label 0: represents "IPv4 Explicit NULL Label".
 120                  */
 121                 if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
 122                         /* Decapsulate the ip datagram from the mpls frame. */
 123                         m_adj(m, sizeof(struct mpls));
 124 /*
 125                         ip_input(m);
 126 */
 127                         netisr_dispatch(NETISR_IP, m);
 128                         return;
 129                 }
 130                 goto again; /* If not the bottom label, per RFC4182. */
 131
 132         case 1:
 133                 /*
 134                  * Label 1: represents "Router Alert Label" and is valid
 135                  * anywhere except at the bottom of the stack.
 136                  */
 137                 break;
 138
 139         case 2:
 140                 /*
 141                  * Label 2: represents "IPv6 Explicit NULL Label".
 142                  */
 143                 if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
 144                         /* Decapsulate the ip datagram from the mpls frame. */
 145                         m_adj(m, sizeof(struct mpls));
 146                         netisr_dispatch(NETISR_IPV6, m);
 147                         return;
 148                 }
 149                 goto again; /* If not the bottom label, per RFC4182. */
 150
 151         case 3:
 152                 /*
 153                  * Label 3: represents the "Implicit NULL Label" and must not
 154                  * appear on the wire.
 155                  */
 156                 break;
 157         default:
 158                 /*
 159                  * Labels 4 - 15: reserved, drop them.
 160                  */
 161                 if (label <= 15) {
 162                         mplsstat.mplss_reserved++;
 163                         m_freem(m);
 164                         return;
 165                 }
 166                 if (mplsforwarding) {
 167                         mpls_forward(m);
 168                         return;
 169                 } else {
 170                         mplsstat.mplss_cantforward++;
 171                         m_freem(m);
 172                         return;
 173                 }
 174         }
 175
 176         mplsstat.mplss_invalid++;
 177         m_freem(m);
 178 }
 179
 180 static void
 181 mpls_forward(struct mbuf *m)
 182 {
 183         struct sockaddr_mpls *smpls;
 184         struct mpls *mpls;
 185         struct route *cache_rt = &mplsforward_rt[mycpuid];
 186         mpls_label_t label;
 187         struct ifnet *ifp;
 188         struct sockaddr *dst;
 189         int error;
 190
 191         KASSERT(m->m_len >= sizeof(struct mpls),
 192             ("mpls_forward: mpls header not in one mbuf"));
 193
 194         mpls = mtod(m, struct mpls *);
 195         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 196
 197         smpls = (struct sockaddr_mpls *) &cache_rt->ro_dst;
 198         if (cache_rt->ro_rt == NULL || smpls->smpls_label != label) {
 199                 if (cache_rt->ro_rt != NULL) {
 200                         RTFREE(cache_rt->ro_rt);
 201                         cache_rt->ro_rt = NULL;
 202                 }
 203                 smpls->smpls_family = AF_MPLS;
 204                 smpls->smpls_len = sizeof(struct sockaddr_mpls);
 205                 smpls->smpls_label = htonl(label);
 206                 rtalloc(cache_rt);
 207                 if (cache_rt->ro_rt == NULL) {
 208                         /* route not found */
 209                         return;
 210                 }
 211         }
 212
 213         ifp = cache_rt->ro_rt->rt_ifp;
 214         dst = cache_rt->ro_rt->rt_gateway;
 215         error = mpls_output(m, cache_rt->ro_rt);
 216         if (error)
 217                 goto bad;
 218         error = (*ifp->if_output)(ifp, m, dst, cache_rt->ro_rt);
 219         if (error)
 220                 goto bad;
 221         mplsstat.mplss_forwarded++;
 222
 223         return;
 224 bad:
 225         m_freem(m);
 226 }