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 * 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 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
30 * $FreeBSD: src/sys/net/if_loop.c,v 1.101.2.2 2005/01/31 23:26:23 imp Exp $
31 */
32
33 /*
34 * Loopback interface driver for protocol testing and timing.
35 */
36
37 #include "opt_atalk.h"
38 #include "opt_inet.h"
39 #include "opt_inet6.h"
40 #include "opt_ipx.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
46 #include <sys/mbuf.h>
47 #include <sys/module.h>
48 #include <machine/bus.h>
49 #include <sys/rman.h>
50 #include <sys/socket.h>
51 #include <sys/sockio.h>
52 #include <sys/sysctl.h>
53
54 #include <net/if.h>
55 #include <net/if_clone.h>
56 #include <net/if_types.h>
57 #include <net/netisr.h>
58 #include <net/route.h>
59 #include <net/bpf.h>
60 #include <net/bpfdesc.h>
61
62 #ifdef INET
63 #include <netinet/in.h>
64 #include <netinet/in_var.h>
65 #endif
66
67 #ifdef IPX
68 #include <netipx/ipx.h>
69 #include <netipx/ipx_if.h>
70 #endif
71
72 #ifdef INET6
73 #ifndef INET
74 #include <netinet/in.h>
75 #endif
76 #include <netinet6/in6_var.h>
77 #include <netinet/ip6.h>
78 #endif
79
80 #ifdef NETATALK
81 #include <netatalk/at.h>
82 #include <netatalk/at_var.h>
83 #endif
84
85 #ifdef TINY_LOMTU
86 #define LOMTU (1024+512)
87 #elif defined(LARGE_LOMTU)
88 #define LOMTU 131072
89 #else
90 #define LOMTU 16384
91 #endif
92
93 #define LONAME "lo"
94
95 struct lo_softc {
96 struct ifnet sc_if; /* network-visible interface */
97 LIST_ENTRY(lo_softc) sc_next;
98 };
99
100 int loioctl(struct ifnet *, u_long, caddr_t);
101 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
102 int looutput(struct ifnet *ifp, struct mbuf *m,
103 struct sockaddr *dst, struct rtentry *rt);
104 static int lo_clone_create(struct if_clone *, int);
105 static void lo_clone_destroy(struct ifnet *);
106
107 struct ifnet *loif = NULL; /* Used externally */
108
109 static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
110
111 static struct mtx lo_mtx;
112 static LIST_HEAD(lo_list, lo_softc) lo_list;
113
114 IFC_SIMPLE_DECLARE(lo, 1);
115
116 static void
117 lo_clone_destroy(ifp)
118 struct ifnet *ifp;
119 {
120 struct lo_softc *sc;
121
122 sc = ifp->if_softc;
123
124 /* XXX: destroying lo0 will lead to panics. */
125 KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
126
127 mtx_lock(&lo_mtx);
128 LIST_REMOVE(sc, sc_next);
129 mtx_unlock(&lo_mtx);
130 bpfdetach(ifp);
131 if_detach(ifp);
132 free(sc, M_LO);
133 }
134
135 static int
136 lo_clone_create(ifc, unit)
137 struct if_clone *ifc;
138 int unit;
139 {
140 struct lo_softc *sc;
141
142 MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
143
144 if_initname(&sc->sc_if, ifc->ifc_name, unit);
145 sc->sc_if.if_mtu = LOMTU;
146 sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
147 sc->sc_if.if_ioctl = loioctl;
148 sc->sc_if.if_output = looutput;
149 sc->sc_if.if_type = IFT_LOOP;
150 sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
151 sc->sc_if.if_softc = sc;
152 if_attach(&sc->sc_if);
153 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
154 mtx_lock(&lo_mtx);
155 LIST_INSERT_HEAD(&lo_list, sc, sc_next);
156 mtx_unlock(&lo_mtx);
157 if (loif == NULL)
158 loif = &sc->sc_if;
159
160 return (0);
161 }
162
163 static int
164 loop_modevent(module_t mod, int type, void *data)
165 {
166 switch (type) {
167 case MOD_LOAD:
168 mtx_init(&lo_mtx, "lo_mtx", NULL, MTX_DEF);
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 default:
176 return EOPNOTSUPP;
177 }
178 return 0;
179 }
180
181 static moduledata_t loop_mod = {
182 "loop",
183 loop_modevent,
184 0
185 };
186
187 DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
188
189 int
190 looutput(ifp, m, dst, rt)
191 struct ifnet *ifp;
192 register struct mbuf *m;
193 struct sockaddr *dst;
194 register struct rtentry *rt;
195 {
196 M_ASSERTPKTHDR(m); /* check if we have the packet header */
197
198 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
199 m_freem(m);
200 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
201 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
202 }
203
204 ifp->if_opackets++;
205 ifp->if_obytes += m->m_pkthdr.len;
206 #if 1 /* XXX */
207 switch (dst->sa_family) {
208 case AF_INET:
209 case AF_INET6:
210 case AF_IPX:
211 case AF_APPLETALK:
212 break;
213 default:
214 printf("looutput: af=%d unexpected\n", dst->sa_family);
215 m_freem(m);
216 return (EAFNOSUPPORT);
217 }
218 #endif
219 return(if_simloop(ifp, m, dst->sa_family, 0));
220 }
221
222 /*
223 * if_simloop()
224 *
225 * This function is to support software emulation of hardware loopback,
226 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
227 * hear their own broadcasts, we create a copy of the packet that we
228 * would normally receive via a hardware loopback.
229 *
230 * This function expects the packet to include the media header of length hlen.
231 */
232
233 int
234 if_simloop(ifp, m, af, hlen)
235 struct ifnet *ifp;
236 struct mbuf *m;
237 int af;
238 int hlen;
239 {
240 int isr;
241
242 M_ASSERTPKTHDR(m);
243 m_tag_delete_nonpersistent(m);
244 m->m_pkthdr.rcvif = ifp;
245
246 /* BPF write needs to be handled specially */
247 if (af == AF_UNSPEC) {
248 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
249 af = *(mtod(m, int *));
250 m->m_len -= sizeof(int);
251 m->m_pkthdr.len -= sizeof(int);
252 m->m_data += sizeof(int);
253 }
254
255 /* Let BPF see incoming packet */
256 if (ifp->if_bpf) {
257 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
258 u_int32_t af1 = af; /* XXX beware sizeof(af) != 4 */
259 /*
260 * We need to prepend the address family.
261 */
262 bpf_mtap2(ifp->if_bpf, &af1, sizeof(af1), m);
263 } else
264 bpf_mtap(ifp->if_bpf, m);
265 }
266
267 /* Strip away media header */
268 if (hlen > 0) {
269 m_adj(m, hlen);
270 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
271 /* The alpha doesn't like unaligned data.
272 * We move data down in the first mbuf */
273 if (mtod(m, vm_offset_t) & 3) {
274 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
275 bcopy(m->m_data,
276 (char *)(mtod(m, vm_offset_t)
277 - (mtod(m, vm_offset_t) & 3)),
278 m->m_len);
279 m->m_data -= (mtod(m,vm_offset_t) & 3);
280 }
281 #endif
282 }
283
284 /* Deliver to upper layer protocol */
285 switch (af) {
286 #ifdef INET
287 case AF_INET:
288 isr = NETISR_IP;
289 break;
290 #endif
291 #ifdef INET6
292 case AF_INET6:
293 m->m_flags |= M_LOOP;
294 isr = NETISR_IPV6;
295 break;
296 #endif
297 #ifdef IPX
298 case AF_IPX:
299 isr = NETISR_IPX;
300 break;
301 #endif
302 #ifdef NETATALK
303 case AF_APPLETALK:
304 isr = NETISR_ATALK2;
305 break;
306 #endif
307 default:
308 printf("if_simloop: can't handle af=%d\n", af);
309 m_freem(m);
310 return (EAFNOSUPPORT);
311 }
312 ifp->if_ipackets++;
313 ifp->if_ibytes += m->m_pkthdr.len;
314 netisr_queue(isr, m); /* mbuf is free'd on failure. */
315 return (0);
316 }
317
318 /* ARGSUSED */
319 static void
320 lortrequest(cmd, rt, info)
321 int cmd;
322 struct rtentry *rt;
323 struct rt_addrinfo *info;
324 {
325 RT_LOCK_ASSERT(rt);
326 if (rt)
327 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
328 }
329
330 /*
331 * Process an ioctl request.
332 */
333 /* ARGSUSED */
334 int
335 loioctl(ifp, cmd, data)
336 register struct ifnet *ifp;
337 u_long cmd;
338 caddr_t data;
339 {
340 register struct ifaddr *ifa;
341 register struct ifreq *ifr = (struct ifreq *)data;
342 register int error = 0;
343
344 switch (cmd) {
345
346 case SIOCSIFADDR:
347 ifp->if_flags |= IFF_UP | IFF_RUNNING;
348 ifa = (struct ifaddr *)data;
349 ifa->ifa_rtrequest = lortrequest;
350 /*
351 * Everything else is done at a higher level.
352 */
353 break;
354
355 case SIOCADDMULTI:
356 case SIOCDELMULTI:
357 if (ifr == 0) {
358 error = EAFNOSUPPORT; /* XXX */
359 break;
360 }
361 switch (ifr->ifr_addr.sa_family) {
362
363 #ifdef INET
364 case AF_INET:
365 break;
366 #endif
367 #ifdef INET6
368 case AF_INET6:
369 break;
370 #endif
371
372 default:
373 error = EAFNOSUPPORT;
374 break;
375 }
376 break;
377
378 case SIOCSIFMTU:
379 ifp->if_mtu = ifr->ifr_mtu;
380 break;
381
382 case SIOCSIFFLAGS:
383 break;
384
385 default:
386 error = EINVAL;
387 }
388 return (error);
389 }
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