sys/net/if_disc.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1982, 1986, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Discard interface driver for protocol testing and timing.
  34  * (Based on the loopback.)
  35  */
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/kernel.h>
  40 #include <sys/malloc.h>
  41 #include <sys/module.h>
  42 #include <sys/mbuf.h>
  43 #include <sys/socket.h>
  44 #include <sys/sockio.h>
  45
  46 #include <net/if.h>
  47 #include <net/if_var.h>
  48 #include <net/if_private.h>
  49 #include <net/if_clone.h>
  50 #include <net/if_types.h>
  51 #include <net/route.h>
  52 #include <net/bpf.h>
  53 #include <net/vnet.h>
  54
  55 #include "opt_inet.h"
  56 #include "opt_inet6.h"
  57
  58 #ifdef TINY_DSMTU
  59 #define DSMTU   (1024+512)
  60 #else
  61 #define DSMTU   65532
  62 #endif
  63
  64 struct disc_softc {
  65         struct ifnet *sc_ifp;
  66 };
  67
  68 static int      discoutput(struct ifnet *, struct mbuf *,
  69                     const struct sockaddr *, struct route *);
  70 static int      discioctl(struct ifnet *, u_long, caddr_t);
  71 static int      disc_clone_create(struct if_clone *, int, caddr_t);
  72 static void     disc_clone_destroy(struct ifnet *);
  73
  74 static const char discname[] = "disc";
  75 static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
  76
  77 VNET_DEFINE_STATIC(struct if_clone *, disc_cloner);
  78 #define V_disc_cloner   VNET(disc_cloner)
  79
  80 static int
  81 disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
  82 {
  83         struct ifnet            *ifp;
  84         struct disc_softc       *sc;
  85
  86         sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
  87         ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
  88         ifp->if_softc = sc;
  89         if_initname(ifp, discname, unit);
  90         ifp->if_mtu = DSMTU;
  91         /*
  92          * IFF_LOOPBACK should not be removed from disc's flags because
  93          * it controls what PF-specific routes are magically added when
  94          * a network address is assigned to the interface.  Things just
  95          * won't work as intended w/o such routes because the output
  96          * interface selection for a packet is totally route-driven.
  97          * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
  98          * IFF_POINTOPOINT, but it would result in different properties
  99          * of the interface.
 100          */
 101         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 102         ifp->if_drv_flags = IFF_DRV_RUNNING;
 103         ifp->if_ioctl = discioctl;
 104         ifp->if_output = discoutput;
 105         ifp->if_hdrlen = 0;
 106         ifp->if_addrlen = 0;
 107         ifp->if_snd.ifq_maxlen = 20;
 108         if_attach(ifp);
 109         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
 110
 111         return (0);
 112 }
 113
 114 static void
 115 disc_clone_destroy(struct ifnet *ifp)
 116 {
 117         struct disc_softc       *sc;
 118
 119         sc = ifp->if_softc;
 120
 121         bpfdetach(ifp);
 122         if_detach(ifp);
 123         if_free(ifp);
 124
 125         free(sc, M_DISC);
 126 }
 127
 128 static void
 129 vnet_disc_init(const void *unused __unused)
 130 {
 131
 132         V_disc_cloner = if_clone_simple(discname, disc_clone_create,
 133             disc_clone_destroy, 0);
 134 }
 135 VNET_SYSINIT(vnet_disc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
 136     vnet_disc_init, NULL);
 137
 138 static void
 139 vnet_disc_uninit(const void *unused __unused)
 140 {
 141
 142         if_clone_detach(V_disc_cloner);
 143 }
 144 VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
 145     vnet_disc_uninit, NULL);
 146
 147 static int
 148 disc_modevent(module_t mod, int type, void *data)
 149 {
 150
 151         switch (type) {
 152         case MOD_LOAD:
 153         case MOD_UNLOAD:
 154                 break;
 155         default:
 156                 return (EOPNOTSUPP);
 157         }
 158         return (0);
 159 }
 160
 161 static moduledata_t disc_mod = {
 162         "if_disc",
 163         disc_modevent,
 164         NULL
 165 };
 166
 167 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
 168
 169 static int
 170 discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 171     struct route *ro)
 172 {
 173         u_int32_t af;
 174
 175         M_ASSERTPKTHDR(m);
 176
 177         /* BPF writes need to be handled specially. */
 178         if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
 179                 bcopy(dst->sa_data, &af, sizeof(af));
 180         else
 181                 af = RO_GET_FAMILY(ro, dst);
 182
 183         if (bpf_peers_present(ifp->if_bpf))
 184                 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
 185
 186         m->m_pkthdr.rcvif = ifp;
 187
 188         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
 189         if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
 190
 191         m_freem(m);
 192         return (0);
 193 }
 194
 195 /*
 196  * Process an ioctl request.
 197  */
 198 static int
 199 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 200 {
 201         struct ifreq *ifr = (struct ifreq *)data;
 202         int error = 0;
 203
 204         switch (cmd) {
 205         case SIOCSIFADDR:
 206                 ifp->if_flags |= IFF_UP;
 207
 208                 /*
 209                  * Everything else is done at a higher level.
 210                  */
 211                 break;
 212         case SIOCADDMULTI:
 213         case SIOCDELMULTI:
 214                 if (ifr == NULL) {
 215                         error = EAFNOSUPPORT;           /* XXX */
 216                         break;
 217                 }
 218                 switch (ifr->ifr_addr.sa_family) {
 219 #ifdef INET
 220                 case AF_INET:
 221                         break;
 222 #endif
 223 #ifdef INET6
 224                 case AF_INET6:
 225                         break;
 226 #endif
 227                 default:
 228                         error = EAFNOSUPPORT;
 229                         break;
 230                 }
 231                 break;
 232         case SIOCSIFMTU:
 233                 ifp->if_mtu = ifr->ifr_mtu;
 234                 break;
 235         default:
 236                 error = EINVAL;
 237         }
 238         return (error);
 239 }