FreeBSD/Linux Kernel Cross Reference
sys/net/if_loop.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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
34 * $FreeBSD: releng/5.2/sys/net/if_loop.c 122922 2003-11-20 20:07:39Z andre $
35 */
36
37 /*
38 * Loopback interface driver for protocol testing and timing.
39 */
40
41 #include "opt_atalk.h"
42 #include "opt_inet.h"
43 #include "opt_inet6.h"
44 #include "opt_ipx.h"
45 #include "opt_mac.h"
46
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
50 #include <sys/mac.h>
51 #include <sys/malloc.h>
52 #include <sys/mbuf.h>
53 #include <sys/module.h>
54 #include <machine/bus.h>
55 #include <sys/rman.h>
56 #include <sys/socket.h>
57 #include <sys/sockio.h>
58 #include <sys/sysctl.h>
59
60 #include <net/if.h>
61 #include <net/if_types.h>
62 #include <net/netisr.h>
63 #include <net/route.h>
64 #include <net/bpf.h>
65 #include <net/bpfdesc.h>
66
67 #ifdef INET
68 #include <netinet/in.h>
69 #include <netinet/in_var.h>
70 #endif
71
72 #ifdef IPX
73 #include <netipx/ipx.h>
74 #include <netipx/ipx_if.h>
75 #endif
76
77 #ifdef INET6
78 #ifndef INET
79 #include <netinet/in.h>
80 #endif
81 #include <netinet6/in6_var.h>
82 #include <netinet/ip6.h>
83 #endif
84
85 #ifdef NETATALK
86 #include <netatalk/at.h>
87 #include <netatalk/at_var.h>
88 #endif
89
90 #ifdef TINY_LOMTU
91 #define LOMTU (1024+512)
92 #elif defined(LARGE_LOMTU)
93 #define LOMTU 131072
94 #else
95 #define LOMTU 16384
96 #endif
97
98 #define LONAME "lo"
99
100 struct lo_softc {
101 struct ifnet sc_if; /* network-visible interface */
102 LIST_ENTRY(lo_softc) sc_next;
103 };
104
105 int loioctl(struct ifnet *, u_long, caddr_t);
106 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
107 int looutput(struct ifnet *ifp, struct mbuf *m,
108 struct sockaddr *dst, struct rtentry *rt);
109 int lo_clone_create(struct if_clone *, int);
110 void lo_clone_destroy(struct ifnet *);
111
112 struct ifnet *loif = NULL; /* Used externally */
113
114 static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
115
116 static LIST_HEAD(lo_list, lo_softc) lo_list;
117
118 struct if_clone lo_cloner = IF_CLONE_INITIALIZER(LONAME,
119 lo_clone_create, lo_clone_destroy, 1, IF_MAXUNIT);
120
121 void
122 lo_clone_destroy(ifp)
123 struct ifnet *ifp;
124 {
125 struct lo_softc *sc;
126
127 sc = ifp->if_softc;
128
129 /* XXX: destroying lo0 will lead to panics. */
130 KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
131
132 bpfdetach(ifp);
133 if_detach(ifp);
134 LIST_REMOVE(sc, sc_next);
135 free(sc, M_LO);
136 }
137
138 int
139 lo_clone_create(ifc, unit)
140 struct if_clone *ifc;
141 int unit;
142 {
143 struct lo_softc *sc;
144
145 MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
146
147 if_initname(&sc->sc_if, ifc->ifc_name, unit);
148 sc->sc_if.if_mtu = LOMTU;
149 sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
150 sc->sc_if.if_ioctl = loioctl;
151 sc->sc_if.if_output = looutput;
152 sc->sc_if.if_type = IFT_LOOP;
153 sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
154 sc->sc_if.if_softc = sc;
155 if_attach(&sc->sc_if);
156 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
157 LIST_INSERT_HEAD(&lo_list, sc, sc_next);
158 if (loif == NULL)
159 loif = &sc->sc_if;
160
161 return (0);
162 }
163
164 static int
165 loop_modevent(module_t mod, int type, void *data)
166 {
167 switch (type) {
168 case MOD_LOAD:
169 LIST_INIT(&lo_list);
170 if_clone_attach(&lo_cloner);
171 break;
172 case MOD_UNLOAD:
173 printf("loop module unload - not possible for this module type\n");
174 return EINVAL;
175 }
176 return 0;
177 }
178
179 static moduledata_t loop_mod = {
180 "loop",
181 loop_modevent,
182 0
183 };
184
185 DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
186
187 int
188 looutput(ifp, m, dst, rt)
189 struct ifnet *ifp;
190 register struct mbuf *m;
191 struct sockaddr *dst;
192 register struct rtentry *rt;
193 {
194 M_ASSERTPKTHDR(m); /* check if we have the packet header */
195
196 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
197 m_freem(m);
198 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
199 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
200 }
201
202 ifp->if_opackets++;
203 ifp->if_obytes += m->m_pkthdr.len;
204 #if 1 /* XXX */
205 switch (dst->sa_family) {
206 case AF_INET:
207 case AF_INET6:
208 case AF_IPX:
209 case AF_APPLETALK:
210 break;
211 default:
212 printf("looutput: af=%d unexpected\n", dst->sa_family);
213 m_freem(m);
214 return (EAFNOSUPPORT);
215 }
216 #endif
217 return(if_simloop(ifp, m, dst->sa_family, 0));
218 }
219
220 /*
221 * if_simloop()
222 *
223 * This function is to support software emulation of hardware loopback,
224 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
225 * hear their own broadcasts, we create a copy of the packet that we
226 * would normally receive via a hardware loopback.
227 *
228 * This function expects the packet to include the media header of length hlen.
229 */
230
231 int
232 if_simloop(ifp, m, af, hlen)
233 struct ifnet *ifp;
234 struct mbuf *m;
235 int af;
236 int hlen;
237 {
238 int isr;
239
240 M_ASSERTPKTHDR(m);
241 m_tag_delete_nonpersistent(m);
242 m->m_pkthdr.rcvif = ifp;
243
244 /* BPF write needs to be handled specially */
245 if (af == AF_UNSPEC) {
246 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
247 af = *(mtod(m, int *));
248 m->m_len -= sizeof(int);
249 m->m_pkthdr.len -= sizeof(int);
250 m->m_data += sizeof(int);
251 }
252
253 /* Let BPF see incoming packet */
254 if (ifp->if_bpf) {
255 struct mbuf m0, *n = m;
256
257 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
258 /*
259 * We need to prepend the address family as
260 * a four byte field. Cons up a dummy header
261 * to pacify bpf. This is safe because bpf
262 * will only read from the mbuf (i.e., it won't
263 * try to free it or keep a pointer a to it).
264 */
265 m0.m_next = m;
266 m0.m_len = 4;
267 m0.m_data = (char *)⁡
268 n = &m0;
269 }
270 BPF_MTAP(ifp, n);
271 }
272
273 /* Strip away media header */
274 if (hlen > 0) {
275 m_adj(m, hlen);
276 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
277 /* The alpha doesn't like unaligned data.
278 * We move data down in the first mbuf */
279 if (mtod(m, vm_offset_t) & 3) {
280 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
281 bcopy(m->m_data,
282 (char *)(mtod(m, vm_offset_t)
283 - (mtod(m, vm_offset_t) & 3)),
284 m->m_len);
285 mtod(m,vm_offset_t) -= (mtod(m, vm_offset_t) & 3);
286 }
287 #endif
288 }
289
290 /* Deliver to upper layer protocol */
291 switch (af) {
292 #ifdef INET
293 case AF_INET:
294 isr = NETISR_IP;
295 break;
296 #endif
297 #ifdef INET6
298 case AF_INET6:
299 m->m_flags |= M_LOOP;
300 isr = NETISR_IPV6;
301 break;
302 #endif
303 #ifdef IPX
304 case AF_IPX:
305 isr = NETISR_IPX;
306 break;
307 #endif
308 #ifdef NETATALK
309 case AF_APPLETALK:
310 isr = NETISR_ATALK2;
311 break;
312 #endif
313 default:
314 printf("if_simloop: can't handle af=%d\n", af);
315 m_freem(m);
316 return (EAFNOSUPPORT);
317 }
318 ifp->if_ipackets++;
319 ifp->if_ibytes += m->m_pkthdr.len;
320 netisr_queue(isr, m);
321 return (0);
322 }
323
324 /* ARGSUSED */
325 static void
326 lortrequest(cmd, rt, info)
327 int cmd;
328 struct rtentry *rt;
329 struct rt_addrinfo *info;
330 {
331 RT_LOCK_ASSERT(rt);
332 if (rt)
333 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
334 }
335
336 /*
337 * Process an ioctl request.
338 */
339 /* ARGSUSED */
340 int
341 loioctl(ifp, cmd, data)
342 register struct ifnet *ifp;
343 u_long cmd;
344 caddr_t data;
345 {
346 register struct ifaddr *ifa;
347 register struct ifreq *ifr = (struct ifreq *)data;
348 register int error = 0;
349
350 switch (cmd) {
351
352 case SIOCSIFADDR:
353 ifp->if_flags |= IFF_UP | IFF_RUNNING;
354 ifa = (struct ifaddr *)data;
355 ifa->ifa_rtrequest = lortrequest;
356 /*
357 * Everything else is done at a higher level.
358 */
359 break;
360
361 case SIOCADDMULTI:
362 case SIOCDELMULTI:
363 if (ifr == 0) {
364 error = EAFNOSUPPORT; /* XXX */
365 break;
366 }
367 switch (ifr->ifr_addr.sa_family) {
368
369 #ifdef INET
370 case AF_INET:
371 break;
372 #endif
373 #ifdef INET6
374 case AF_INET6:
375 break;
376 #endif
377
378 default:
379 error = EAFNOSUPPORT;
380 break;
381 }
382 break;
383
384 case SIOCSIFMTU:
385 ifp->if_mtu = ifr->ifr_mtu;
386 break;
387
388 case SIOCSIFFLAGS:
389 break;
390
391 default:
392 error = EINVAL;
393 }
394 return (error);
395 }
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