1/*- 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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 the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
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31 */ 32 33/* 34 * Discard interface driver for protocol testing and timing. 35 * (Based on the loopback.) 36 */ 37 38#include <sys/param.h> 39#include <sys/systm.h> 40#include <sys/kernel.h> 41#include <sys/malloc.h> 42#include <sys/module.h> 43#include <sys/mbuf.h> 44#include <sys/socket.h> 45#include <sys/sockio.h> 46 47#include <net/if.h> 48#include <net/if_var.h> 49#include <net/if_clone.h> 50#include <net/if_types.h> 51#include <net/route.h> 52#include <net/bpf.h> 53 54#include "opt_inet.h" 55#include "opt_inet6.h" 56 57#ifdef TINY_DSMTU 58#define DSMTU (1024+512) 59#else 60#define DSMTU 65532 61#endif 62 63struct disc_softc { 64 struct ifnet *sc_ifp; 65}; 66 67static int discoutput(struct ifnet *, struct mbuf *, 68 const struct sockaddr *, struct route *); 69static void discrtrequest(int, struct rtentry *, struct rt_addrinfo *); 70static int discioctl(struct ifnet *, u_long, caddr_t); 71static int disc_clone_create(struct if_clone *, int, caddr_t); 72static void disc_clone_destroy(struct ifnet *); 73 74static const char discname[] = "disc"; 75static MALLOC_DEFINE(M_DISC, discname, "Discard interface"); 76 77static struct if_clone *disc_cloner; 78 79static int 80disc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 81{ 82 struct ifnet *ifp; 83 struct disc_softc *sc; 84 85 sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO); 86 ifp = sc->sc_ifp = if_alloc(IFT_LOOP); 87 if (ifp == NULL) { 88 free(sc, M_DISC); 89 return (ENOSPC); 90 } 91 92 ifp->if_softc = sc; 93 if_initname(ifp, discname, unit); 94 ifp->if_mtu = DSMTU; 95 /* 96 * IFF_LOOPBACK should not be removed from disc's flags because 97 * it controls what PF-specific routes are magically added when 98 * a network address is assigned to the interface. Things just 99 * won't work as intended w/o such routes because the output 100 * interface selection for a packet is totally route-driven. 101 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or 102 * IFF_POINTOPOINT, but it would result in different properties 103 * of the interface. 104 */ 105 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST; 106 ifp->if_drv_flags = IFF_DRV_RUNNING; 107 ifp->if_ioctl = discioctl; 108 ifp->if_output = discoutput; 109 ifp->if_hdrlen = 0; 110 ifp->if_addrlen = 0; 111 ifp->if_snd.ifq_maxlen = 20; 112 if_attach(ifp); 113 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t)); 114 115 return (0); 116} 117 118static void 119disc_clone_destroy(struct ifnet *ifp) 120{ 121 struct disc_softc *sc; 122 123 sc = ifp->if_softc; 124 125 bpfdetach(ifp); 126 if_detach(ifp); 127 if_free(ifp); 128 129 free(sc, M_DISC); 130} 131 132static int 133disc_modevent(module_t mod, int type, void *data) 134{ 135 136 switch (type) { 137 case MOD_LOAD: 138 disc_cloner = if_clone_simple(discname, disc_clone_create, 139 disc_clone_destroy, 0); 140 break; 141 case MOD_UNLOAD: 142 if_clone_detach(disc_cloner); 143 break; 144 default: 145 return (EOPNOTSUPP); 146 } 147 return (0); 148} 149 150static moduledata_t disc_mod = { 151 "if_disc", 152 disc_modevent, 153 NULL 154}; 155 156DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 157 158static int 159discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 160 struct route *ro) 161{ 162 u_int32_t af; 163 164 M_ASSERTPKTHDR(m); 165 166 /* BPF writes need to be handled specially. */ 167 if (dst->sa_family == AF_UNSPEC) 168 bcopy(dst->sa_data, &af, sizeof(af)); 169 else 170 af = dst->sa_family; 171 172 if (bpf_peers_present(ifp->if_bpf)) 173 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 174 175 m->m_pkthdr.rcvif = ifp; 176 177 ifp->if_opackets++; 178 ifp->if_obytes += m->m_pkthdr.len; 179 180 m_freem(m); 181 return (0); 182} 183 184/* ARGSUSED */ 185static void 186discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info) 187{ 188 RT_LOCK_ASSERT(rt);
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