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
disc_clone_create(struct if_clone * ifc,int unit,caddr_t params)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
disc_clone_destroy(struct ifnet * ifp)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
vnet_disc_init(const void * unused __unused)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
vnet_disc_uninit(const void * unused __unused)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
disc_modevent(module_t mod,int type,void * data)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
discoutput(struct ifnet * ifp,struct mbuf * m,const struct sockaddr * dst,struct route * ro)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
discioctl(struct ifnet * ifp,u_long cmd,caddr_t data)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