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 if (ifp == NULL) { 89 free(sc, M_DISC); 90 return (ENOSPC); 91 } 92 93 ifp->if_softc = sc; 94 if_initname(ifp, discname, unit); 95 ifp->if_mtu = DSMTU; 96 /* 97 * IFF_LOOPBACK should not be removed from disc's flags because 98 * it controls what PF-specific routes are magically added when 99 * a network address is assigned to the interface. Things just 100 * won't work as intended w/o such routes because the output 101 * interface selection for a packet is totally route-driven. 102 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or 103 * IFF_POINTOPOINT, but it would result in different properties 104 * of the interface. 105 */ 106 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST; 107 ifp->if_drv_flags = IFF_DRV_RUNNING; 108 ifp->if_ioctl = discioctl; 109 ifp->if_output = discoutput; 110 ifp->if_hdrlen = 0; 111 ifp->if_addrlen = 0; 112 ifp->if_snd.ifq_maxlen = 20; 113 if_attach(ifp); 114 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t)); 115 116 return (0); 117 } 118 119 static void 120 disc_clone_destroy(struct ifnet *ifp) 121 { 122 struct disc_softc *sc; 123 124 sc = ifp->if_softc; 125 126 bpfdetach(ifp); 127 if_detach(ifp); 128 if_free(ifp); 129 130 free(sc, M_DISC); 131 } 132 133 static void 134 vnet_disc_init(const void *unused __unused) 135 { 136 137 V_disc_cloner = if_clone_simple(discname, disc_clone_create, 138 disc_clone_destroy, 0); 139 } 140 VNET_SYSINIT(vnet_disc_init, SI_SUB_PSEUDO, SI_ORDER_ANY, 141 vnet_disc_init, NULL); 142 143 static void 144 vnet_disc_uninit(const void *unused __unused) 145 { 146 147 if_clone_detach(V_disc_cloner); 148 } 149 VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY, 150 vnet_disc_uninit, NULL); 151 152 static int 153 disc_modevent(module_t mod, int type, void *data) 154 { 155 156 switch (type) { 157 case MOD_LOAD: 158 case MOD_UNLOAD: 159 break; 160 default: 161 return (EOPNOTSUPP); 162 } 163 return (0); 164 } 165 166 static moduledata_t disc_mod = { 167 "if_disc", 168 disc_modevent, 169 NULL 170 }; 171 172 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 173 174 static int 175 discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 176 struct route *ro) 177 { 178 u_int32_t af; 179 180 M_ASSERTPKTHDR(m); 181 182 /* BPF writes need to be handled specially. */ 183 if (dst->sa_family == AF_UNSPEC) 184 bcopy(dst->sa_data, &af, sizeof(af)); 185 else 186 af = RO_GET_FAMILY(ro, dst); 187 188 if (bpf_peers_present(ifp->if_bpf)) 189 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 190 191 m->m_pkthdr.rcvif = ifp; 192 193 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 194 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len); 195 196 m_freem(m); 197 return (0); 198 } 199 200 /* 201 * Process an ioctl request. 202 */ 203 static int 204 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 205 { 206 struct ifreq *ifr = (struct ifreq *)data; 207 int error = 0; 208 209 switch (cmd) { 210 case SIOCSIFADDR: 211 ifp->if_flags |= IFF_UP; 212 213 /* 214 * Everything else is done at a higher level. 215 */ 216 break; 217 case SIOCADDMULTI: 218 case SIOCDELMULTI: 219 if (ifr == NULL) { 220 error = EAFNOSUPPORT; /* XXX */ 221 break; 222 } 223 switch (ifr->ifr_addr.sa_family) { 224 #ifdef INET 225 case AF_INET: 226 break; 227 #endif 228 #ifdef INET6 229 case AF_INET6: 230 break; 231 #endif 232 default: 233 error = EAFNOSUPPORT; 234 break; 235 } 236 break; 237 case SIOCSIFMTU: 238 ifp->if_mtu = ifr->ifr_mtu; 239 break; 240 default: 241 error = EINVAL; 242 } 243 return (error); 244 } 245