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 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93 32 * $FreeBSD$ 33 */ 34 35 /* 36 * Discard interface driver for protocol testing and timing. 37 * (Based on the loopback.) 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/malloc.h> 44 #include <sys/module.h> 45 #include <sys/mbuf.h> 46 #include <sys/socket.h> 47 #include <sys/sockio.h> 48 49 #include <net/if.h> 50 #include <net/if_var.h> 51 #include <net/if_private.h> 52 #include <net/if_clone.h> 53 #include <net/if_types.h> 54 #include <net/route.h> 55 #include <net/bpf.h> 56 #include <net/vnet.h> 57 58 #include "opt_inet.h" 59 #include "opt_inet6.h" 60 61 #ifdef TINY_DSMTU 62 #define DSMTU (1024+512) 63 #else 64 #define DSMTU 65532 65 #endif 66 67 struct disc_softc { 68 struct ifnet *sc_ifp; 69 }; 70 71 static int discoutput(struct ifnet *, struct mbuf *, 72 const struct sockaddr *, struct route *); 73 static int discioctl(struct ifnet *, u_long, caddr_t); 74 static int disc_clone_create(struct if_clone *, int, caddr_t); 75 static void disc_clone_destroy(struct ifnet *); 76 77 static const char discname[] = "disc"; 78 static MALLOC_DEFINE(M_DISC, discname, "Discard interface"); 79 80 VNET_DEFINE_STATIC(struct if_clone *, disc_cloner); 81 #define V_disc_cloner VNET(disc_cloner) 82 83 static int 84 disc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 85 { 86 struct ifnet *ifp; 87 struct disc_softc *sc; 88 89 sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO); 90 ifp = sc->sc_ifp = if_alloc(IFT_LOOP); 91 if (ifp == NULL) { 92 free(sc, M_DISC); 93 return (ENOSPC); 94 } 95 96 ifp->if_softc = sc; 97 if_initname(ifp, discname, unit); 98 ifp->if_mtu = DSMTU; 99 /* 100 * IFF_LOOPBACK should not be removed from disc's flags because 101 * it controls what PF-specific routes are magically added when 102 * a network address is assigned to the interface. Things just 103 * won't work as intended w/o such routes because the output 104 * interface selection for a packet is totally route-driven. 105 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or 106 * IFF_POINTOPOINT, but it would result in different properties 107 * of the interface. 108 */ 109 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST; 110 ifp->if_drv_flags = IFF_DRV_RUNNING; 111 ifp->if_ioctl = discioctl; 112 ifp->if_output = discoutput; 113 ifp->if_hdrlen = 0; 114 ifp->if_addrlen = 0; 115 ifp->if_snd.ifq_maxlen = 20; 116 if_attach(ifp); 117 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t)); 118 119 return (0); 120 } 121 122 static void 123 disc_clone_destroy(struct ifnet *ifp) 124 { 125 struct disc_softc *sc; 126 127 sc = ifp->if_softc; 128 129 bpfdetach(ifp); 130 if_detach(ifp); 131 if_free(ifp); 132 133 free(sc, M_DISC); 134 } 135 136 static void 137 vnet_disc_init(const void *unused __unused) 138 { 139 140 V_disc_cloner = if_clone_simple(discname, disc_clone_create, 141 disc_clone_destroy, 0); 142 } 143 VNET_SYSINIT(vnet_disc_init, SI_SUB_PSEUDO, SI_ORDER_ANY, 144 vnet_disc_init, NULL); 145 146 static void 147 vnet_disc_uninit(const void *unused __unused) 148 { 149 150 if_clone_detach(V_disc_cloner); 151 } 152 VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY, 153 vnet_disc_uninit, NULL); 154 155 static int 156 disc_modevent(module_t mod, int type, void *data) 157 { 158 159 switch (type) { 160 case MOD_LOAD: 161 case MOD_UNLOAD: 162 break; 163 default: 164 return (EOPNOTSUPP); 165 } 166 return (0); 167 } 168 169 static moduledata_t disc_mod = { 170 "if_disc", 171 disc_modevent, 172 NULL 173 }; 174 175 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 176 177 static int 178 discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 179 struct route *ro) 180 { 181 u_int32_t af; 182 183 M_ASSERTPKTHDR(m); 184 185 /* BPF writes need to be handled specially. */ 186 if (dst->sa_family == AF_UNSPEC) 187 bcopy(dst->sa_data, &af, sizeof(af)); 188 else 189 af = RO_GET_FAMILY(ro, dst); 190 191 if (bpf_peers_present(ifp->if_bpf)) 192 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 193 194 m->m_pkthdr.rcvif = ifp; 195 196 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 197 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len); 198 199 m_freem(m); 200 return (0); 201 } 202 203 /* 204 * Process an ioctl request. 205 */ 206 static int 207 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 208 { 209 struct ifreq *ifr = (struct ifreq *)data; 210 int error = 0; 211 212 switch (cmd) { 213 case SIOCSIFADDR: 214 ifp->if_flags |= IFF_UP; 215 216 /* 217 * Everything else is done at a higher level. 218 */ 219 break; 220 case SIOCADDMULTI: 221 case SIOCDELMULTI: 222 if (ifr == NULL) { 223 error = EAFNOSUPPORT; /* XXX */ 224 break; 225 } 226 switch (ifr->ifr_addr.sa_family) { 227 #ifdef INET 228 case AF_INET: 229 break; 230 #endif 231 #ifdef INET6 232 case AF_INET6: 233 break; 234 #endif 235 default: 236 error = EAFNOSUPPORT; 237 break; 238 } 239 break; 240 case SIOCSIFMTU: 241 ifp->if_mtu = ifr->ifr_mtu; 242 break; 243 default: 244 error = EINVAL; 245 } 246 return (error); 247 } 248