FreeBSD/Linux Kernel Cross Reference
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 * 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 }
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