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/thread2.h>
  44 #include <sys/mplock2.h>
  45
  46 #include <netproto/mpls/mpls.h>
  47 #include <netproto/mpls/mpls_var.h>
  48
  49 struct mpls_stats       mplsstats_percpu[MAXCPU];
  50 struct route            mplsforward_rt[MAXCPU];
  51
  52 int mplsforwarding = 1;
  53 /*
  54 SYSCTL_INT(_net_mpls, OID_AUTO, forwarding, CTLFLAG_RW,
  55     &mplsforwarding, 0, "Enable MPLS forwarding between interfaces");
  56 */
  57
  58 static void     mpls_input_handler(netmsg_t);
  59 static void     mpls_forward(struct mbuf *);
  60
  61 void
  62 mpls_init(void)
  63 {
  64         int cpu;
  65
  66         /*
  67          * Initialize MPLS statistics counters for each CPU.
  68          *
  69          */
  70         for (cpu = 0; cpu < ncpus; ++cpu) {
  71                 bzero(&mplsstats_percpu[cpu], sizeof(struct mpls_stats));
  72         }
  73
  74         netisr_register(NETISR_MPLS, mpls_input_handler, mpls_hashfn);
  75 }
  76
  77 static void
  78 mpls_input_handler(netmsg_t msg)
  79 {
  80         struct mbuf *m = msg->packet.nm_packet;
  81
  82         get_mplock();
  83         mpls_input(m);
  84         rel_mplock();
  85         /* do not reply, msg embedded in mbuf */
  86 }
  87
  88 void
  89 mpls_input(struct mbuf *m)
  90 {
  91         struct mpls *mpls = NULL;
  92         mpls_label_t label;
  93
  94         M_ASSERTPKTHDR(m);
  95
  96         mplsstat.mplss_total++;
  97
  98         /* length checks already performed at mpls_demux() */
  99         KASSERT(m->m_pkthdr.len >= sizeof(struct mpls),
 100             ("mpls_input: mpls header too small"));
 101
 102 again:
 103         if (m->m_len < sizeof(struct mpls)) {
 104                 m = m_pullup(m, sizeof(struct mpls));
 105                 if (m == NULL) {
 106                         mplsstat.mplss_toosmall++;
 107                         return;
 108                 }
 109         }
 110
 111         mpls = mtod(m, struct mpls*);
 112         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 113         switch (label) {
 114         case 0:
 115                 /*
 116                  * Label 0: represents "IPv4 Explicit NULL Label".
 117                  */
 118                 if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
 119                         /* Decapsulate the ip datagram from the mpls frame. */
 120                         m_adj(m, sizeof(struct mpls));
 121                         netisr_queue(NETISR_IP, m);
 122                         return;
 123                 }
 124                 goto again; /* If not the bottom label, per RFC4182. */
 125
 126         case 1:
 127                 /*
 128                  * Label 1: represents "Router Alert Label" and is valid
 129                  * anywhere except at the bottom of the stack.
 130                  */
 131                 break;
 132
 133         case 2:
 134                 /*
 135                  * Label 2: represents "IPv6 Explicit NULL Label".
 136                  */
 137                 if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
 138                         /* Decapsulate the ip datagram from the mpls frame. */
 139                         m_adj(m, sizeof(struct mpls));
 140                         netisr_queue(NETISR_IPV6, m);
 141                         return;
 142                 }
 143                 goto again; /* If not the bottom label, per RFC4182. */
 144
 145         case 3:
 146                 /*
 147                  * Label 3: represents the "Implicit NULL Label" and must not
 148                  * appear on the wire.
 149                  */
 150                 break;
 151         default:
 152                 /*
 153                  * Labels 4 - 15: reserved, drop them.
 154                  */
 155                 if (label <= 15) {
 156                         mplsstat.mplss_reserved++;
 157                         m_freem(m);
 158                         return;
 159                 }
 160                 if (mplsforwarding) {
 161                         mpls_forward(m);
 162                         return;
 163                 } else {
 164                         mplsstat.mplss_cantforward++;
 165                         m_freem(m);
 166                         return;
 167                 }
 168         }
 169
 170         mplsstat.mplss_invalid++;
 171         m_freem(m);
 172 }
 173
 174 static void
 175 mpls_forward(struct mbuf *m)
 176 {
 177         struct sockaddr_mpls *smpls;
 178         struct mpls *mpls;
 179         struct route *cache_rt = &mplsforward_rt[mycpuid];
 180         mpls_label_t label;
 181         struct ifnet *ifp;
 182         struct sockaddr *dst;
 183         int error;
 184
 185         KASSERT(m->m_len >= sizeof(struct mpls),
 186             ("mpls_forward: mpls header not in one mbuf"));
 187
 188         mpls = mtod(m, struct mpls *);
 189         label = MPLS_LABEL(ntohl(mpls->mpls_shim));
 190
 191         smpls = (struct sockaddr_mpls *) &cache_rt->ro_dst;
 192         if (cache_rt->ro_rt == NULL || smpls->smpls_label != label) {
 193                 if (cache_rt->ro_rt != NULL) {
 194                         RTFREE(cache_rt->ro_rt);
 195                         cache_rt->ro_rt = NULL;
 196                 }
 197                 smpls->smpls_family = AF_MPLS;
 198                 smpls->smpls_len = sizeof(struct sockaddr_mpls);
 199                 smpls->smpls_label = htonl(label);
 200                 rtalloc(cache_rt);
 201                 if (cache_rt->ro_rt == NULL) {
 202                         /* route not found */
 203                         return;
 204                 }
 205         }
 206
 207         ifp = cache_rt->ro_rt->rt_ifp;
 208         dst = cache_rt->ro_rt->rt_gateway;
 209         error = mpls_output(m, cache_rt->ro_rt);
 210         if (error)
 211                 goto bad;
 212         error = (*ifp->if_output)(ifp, m, dst, cache_rt->ro_rt);
 213         if (error)
 214                 goto bad;
 215         mplsstat.mplss_forwarded++;
 216
 217         return;
 218 bad:
 219         m_freem(m);
 220 }