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
  32 #include <sys/globaldata.h>
  33 #include <sys/kernel.h>
  34 #include <sys/mbuf.h>
  35 #include <sys/param.h>
  36 #include <sys/sysctl.h>
  37 #include <sys/systm.h>
  38
  39 #include <net/if_var.h>
  40 #include <net/netisr.h>
  41 #include <net/route.h>
  42
  43 #include <sys/mplock2.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(netmsg_t);
  58 static void     mpls_forward(struct mbuf *);
  59
  60 void
  61 mpls_init(void)
  62 {
  63         int cpu;
  64
  65         /*
  66          * Initialize MPLS statistics counters for each CPU.
  67          *
  68          */
  69         for (cpu = 0; cpu < ncpus; ++cpu) {
  70                 bzero(&mplsstats_percpu[cpu], sizeof(struct mpls_stats));
  71         }
  72
  73         netisr_register(NETISR_MPLS, mpls_input_handler, mpls_hashfn);
  74 }
  75
  76 static void
  77 mpls_input_handler(netmsg_t msg)
  78 {
  79         struct mbuf *m = msg->packet.nm_packet;
  80
  81         get_mplock();
  82         mpls_input(m);
  83         rel_mplock();
  84         /* do not reply, msg embedded in mbuf */
  85 }
  86
  87 void
  88 mpls_input(struct mbuf *m)
  89 {
  90         struct mpls *mpls = NULL;
  91         mpls_label_t label;
  92
  93         M_ASSERTPKTHDR(m);
  94
  95         mplsstat.mplss_total++;
  96
  97         /* length checks already performed at mpls_demux() */
  98         KASSERT(m->m_pkthdr.len >= sizeof(struct mpls),
  99             ("mpls_input: mpls header too small"));
 100
 101 again:
 102         if (m->m_len < sizeof(struct mpls)) {
 103                 m = m_pullup(m, sizeof(struct mpls));
 104                 if (m == NULL) {
 105                         mplsstat.mplss_toosmall++;
 106                         return;
 107                 }
 108         }
 109
 110         mpls = mtod(m, struct mpls*);
 111         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 112         switch (label) {
 113         case 0:
 114                 /*
 115                  * Label 0: represents "IPv4 Explicit NULL Label".
 116                  */
 117                 if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
 118                         /* Decapsulate the ip datagram from the mpls frame. */
 119                         m_adj(m, sizeof(struct mpls));
 120                         netisr_queue(NETISR_IP, m);
 121                         return;
 122                 }
 123                 goto again; /* If not the bottom label, per RFC4182. */
 124
 125         case 1:
 126                 /*
 127                  * Label 1: represents "Router Alert Label" and is valid
 128                  * anywhere except at the bottom of the stack.
 129                  */
 130                 break;
 131
 132         case 2:
 133                 /*
 134                  * Label 2: represents "IPv6 Explicit NULL Label".
 135                  */
 136                 if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
 137                         /* Decapsulate the ip datagram from the mpls frame. */
 138                         m_adj(m, sizeof(struct mpls));
 139                         netisr_queue(NETISR_IPV6, m);
 140                         return;
 141                 }
 142                 goto again; /* If not the bottom label, per RFC4182. */
 143
 144         case 3:
 145                 /*
 146                  * Label 3: represents the "Implicit NULL Label" and must not
 147                  * appear on the wire.
 148                  */
 149                 break;
 150         default:
 151                 /*
 152                  * Labels 4 - 15: reserved, drop them.
 153                  */
 154                 if (label <= 15) {
 155                         mplsstat.mplss_reserved++;
 156                         m_freem(m);
 157                         return;
 158                 }
 159                 if (mplsforwarding) {
 160                         mpls_forward(m);
 161                         return;
 162                 } else {
 163                         mplsstat.mplss_cantforward++;
 164                         m_freem(m);
 165                         return;
 166                 }
 167         }
 168
 169         mplsstat.mplss_invalid++;
 170         m_freem(m);
 171 }
 172
 173 static void
 174 mpls_forward(struct mbuf *m)
 175 {
 176         struct sockaddr_mpls *smpls;
 177         struct mpls *mpls;
 178         struct route *cache_rt = &mplsforward_rt[mycpuid];
 179         mpls_label_t label;
 180         struct ifnet *ifp;
 181         struct sockaddr *dst;
 182         int error;
 183
 184         KASSERT(m->m_len >= sizeof(struct mpls),
 185             ("mpls_forward: mpls header not in one mbuf"));
 186
 187         mpls = mtod(m, struct mpls *);
 188         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 189
 190         smpls = (struct sockaddr_mpls *) &cache_rt->ro_dst;
 191         if (cache_rt->ro_rt == NULL || smpls->smpls_label != label) {
 192                 if (cache_rt->ro_rt != NULL) {
 193                         RTFREE(cache_rt->ro_rt);
 194                         cache_rt->ro_rt = NULL;
 195                 }
 196                 smpls->smpls_family = AF_MPLS;
 197                 smpls->smpls_len = sizeof(struct sockaddr_mpls);
 198                 smpls->smpls_label = htonl(label);
 199                 rtalloc(cache_rt);
 200                 if (cache_rt->ro_rt == NULL) {
 201                         /* route not found */
 202                         return;
 203                 }
 204         }
 205
 206         ifp = cache_rt->ro_rt->rt_ifp;
 207         dst = cache_rt->ro_rt->rt_gateway;
 208         error = mpls_output(m, cache_rt->ro_rt);
 209         if (error)
 210                 goto bad;
 211         error = (*ifp->if_output)(ifp, m, dst, cache_rt->ro_rt);
 212         if (error)
 213                 goto bad;
 214         mplsstat.mplss_forwarded++;
 215
 216         return;
 217 bad:
 218         m_freem(m);
 219 }