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