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: src/sys/net/if_disc.c,v 1.55 2007/10/27 19:57:41 yar Exp $
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 #define DISCNAME "disc"
63
64 struct disc_softc {
65 struct ifnet *sc_ifp;
66 };
67
68 static int discoutput(struct ifnet *, struct mbuf *,
69 struct sockaddr *, struct rtentry *);
70 static void discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
71 static int discioctl(struct ifnet *, u_long, caddr_t);
72 static int disc_clone_create(struct if_clone *, int, caddr_t);
73 static void disc_clone_destroy(struct ifnet *);
74
75 static MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
76
77 IFC_SIMPLE_DECLARE(disc, 0);
78
79 static int
80 disc_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, ifc->ifc_name, 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
118 static void
119 disc_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
132 static int
133 disc_modevent(module_t mod, int type, void *data)
134 {
135
136 switch (type) {
137 case MOD_LOAD:
138 if_clone_attach(&disc_cloner);
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, struct sockaddr *dst,
159 struct rtentry *rt)
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 dst->sa_family = af;
169 }
170
171 if (bpf_peers_present(ifp->if_bpf)) {
172 u_int af = dst->sa_family;
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 */
185 static void
186 discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
187 {
188 RT_LOCK_ASSERT(rt);
189 rt->rt_rmx.rmx_mtu = DSMTU;
190 }
191
192 /*
193 * Process an ioctl request.
194 */
195 static int
196 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
197 {
198 struct ifaddr *ifa;
199 struct ifreq *ifr = (struct ifreq *)data;
200 int error = 0;
201
202 switch (cmd) {
203
204 case SIOCSIFADDR:
205 ifp->if_flags |= IFF_UP;
206 ifa = (struct ifaddr *)data;
207 if (ifa != 0)
208 ifa->ifa_rtrequest = discrtrequest;
209 /*
210 * Everything else is done at a higher level.
211 */
212 break;
213
214 case SIOCADDMULTI:
215 case SIOCDELMULTI:
216 if (ifr == 0) {
217 error = EAFNOSUPPORT; /* XXX */
218 break;
219 }
220 switch (ifr->ifr_addr.sa_family) {
221
222 #ifdef INET
223 case AF_INET:
224 break;
225 #endif
226 #ifdef INET6
227 case AF_INET6:
228 break;
229 #endif
230
231 default:
232 error = EAFNOSUPPORT;
233 break;
234 }
235 break;
236
237 case SIOCSIFMTU:
238 ifp->if_mtu = ifr->ifr_mtu;
239 break;
240
241 default:
242 error = EINVAL;
243 }
244 return (error);
245 }
246
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