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 } 240