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 * $FreeBSD$
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_ifp;
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 if_free(ifp);
133 free(sc, M_LO);
134 }
135
136 static int
137 lo_clone_create(ifc, unit)
138 struct if_clone *ifc;
139 int unit;
140 {
141 struct ifnet *ifp;
142 struct lo_softc *sc;
143
144 MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
145 ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
146 if (ifp == NULL) {
147 free(sc, M_LO);
148 return (ENOSPC);
149 }
150
151 if_initname(ifp, ifc->ifc_name, unit);
152 ifp->if_mtu = LOMTU;
153 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
154 ifp->if_ioctl = loioctl;
155 ifp->if_output = looutput;
156 ifp->if_snd.ifq_maxlen = ifqmaxlen;
157 ifp->if_softc = sc;
158 if_attach(ifp);
159 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
160 mtx_lock(&lo_mtx);
161 LIST_INSERT_HEAD(&lo_list, sc, sc_next);
162 mtx_unlock(&lo_mtx);
163 if (loif == NULL)
164 loif = ifp;
165
166 return (0);
167 }
168
169 static int
170 loop_modevent(module_t mod, int type, void *data)
171 {
172 switch (type) {
173 case MOD_LOAD:
174 mtx_init(&lo_mtx, "lo_mtx", NULL, MTX_DEF);
175 LIST_INIT(&lo_list);
176 if_clone_attach(&lo_cloner);
177 break;
178 case MOD_UNLOAD:
179 printf("loop module unload - not possible for this module type\n");
180 return EINVAL;
181 default:
182 return EOPNOTSUPP;
183 }
184 return 0;
185 }
186
187 static moduledata_t loop_mod = {
188 "loop",
189 loop_modevent,
190 0
191 };
192
193 DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
194
195 int
196 looutput(ifp, m, dst, rt)
197 struct ifnet *ifp;
198 register struct mbuf *m;
199 struct sockaddr *dst;
200 register struct rtentry *rt;
201 {
202 u_int32_t af;
203
204 M_ASSERTPKTHDR(m); /* check if we have the packet header */
205
206 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
207 m_freem(m);
208 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
209 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
210 }
211
212 ifp->if_opackets++;
213 ifp->if_obytes += m->m_pkthdr.len;
214
215 /* BPF writes need to be handled specially. */
216 if (dst->sa_family == AF_UNSPEC) {
217 bcopy(dst->sa_data, &af, sizeof(af));
218 dst->sa_family = af;
219 }
220
221 #if 1 /* XXX */
222 switch (dst->sa_family) {
223 case AF_INET:
224 case AF_INET6:
225 case AF_IPX:
226 case AF_APPLETALK:
227 break;
228 default:
229 printf("looutput: af=%d unexpected\n", dst->sa_family);
230 m_freem(m);
231 return (EAFNOSUPPORT);
232 }
233 #endif
234 return(if_simloop(ifp, m, dst->sa_family, 0));
235 }
236
237 /*
238 * if_simloop()
239 *
240 * This function is to support software emulation of hardware loopback,
241 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
242 * hear their own broadcasts, we create a copy of the packet that we
243 * would normally receive via a hardware loopback.
244 *
245 * This function expects the packet to include the media header of length hlen.
246 */
247
248 int
249 if_simloop(ifp, m, af, hlen)
250 struct ifnet *ifp;
251 struct mbuf *m;
252 int af;
253 int hlen;
254 {
255 int isr;
256
257 M_ASSERTPKTHDR(m);
258 m_tag_delete_nonpersistent(m);
259 m->m_pkthdr.rcvif = ifp;
260
261 /*
262 * Let BPF see incoming packet in the following manner:
263 * - Emulated packet loopback for a simplex interface
264 * (net/if_ethersubr.c)
265 * -> passes it to ifp's BPF
266 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
267 * -> not passes it to any BPF
268 * - Normal packet loopback from myself to myself (net/if_loop.c)
269 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
270 */
271 if (hlen > 0) {
272 if (bpf_peers_present(ifp->if_bpf)) {
273 bpf_mtap(ifp->if_bpf, m);
274 }
275 } else {
276 if (bpf_peers_present(loif->if_bpf)) {
277 if ((m->m_flags & M_MCAST) == 0 || loif == ifp) {
278 /* XXX beware sizeof(af) != 4 */
279 u_int32_t af1 = af;
280
281 /*
282 * We need to prepend the address family.
283 */
284 bpf_mtap2(loif->if_bpf, &af1, sizeof(af1), m);
285 }
286 }
287 }
288
289 /* Strip away media header */
290 if (hlen > 0) {
291 m_adj(m, hlen);
292 #ifndef __NO_STRICT_ALIGNMENT
293 /* The alpha doesn't like unaligned data.
294 * We move data down in the first mbuf */
295 if (mtod(m, vm_offset_t) & 3) {
296 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
297 bcopy(m->m_data,
298 (char *)(mtod(m, vm_offset_t)
299 - (mtod(m, vm_offset_t) & 3)),
300 m->m_len);
301 m->m_data -= (mtod(m,vm_offset_t) & 3);
302 }
303 #endif
304 }
305
306 /* Deliver to upper layer protocol */
307 switch (af) {
308 #ifdef INET
309 case AF_INET:
310 isr = NETISR_IP;
311 break;
312 #endif
313 #ifdef INET6
314 case AF_INET6:
315 m->m_flags |= M_LOOP;
316 isr = NETISR_IPV6;
317 break;
318 #endif
319 #ifdef IPX
320 case AF_IPX:
321 isr = NETISR_IPX;
322 break;
323 #endif
324 #ifdef NETATALK
325 case AF_APPLETALK:
326 isr = NETISR_ATALK2;
327 break;
328 #endif
329 default:
330 printf("if_simloop: can't handle af=%d\n", af);
331 m_freem(m);
332 return (EAFNOSUPPORT);
333 }
334 ifp->if_ipackets++;
335 ifp->if_ibytes += m->m_pkthdr.len;
336 netisr_queue(isr, m); /* mbuf is free'd on failure. */
337 return (0);
338 }
339
340 /* ARGSUSED */
341 static void
342 lortrequest(cmd, rt, info)
343 int cmd;
344 struct rtentry *rt;
345 struct rt_addrinfo *info;
346 {
347 RT_LOCK_ASSERT(rt);
348 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
349 }
350
351 /*
352 * Process an ioctl request.
353 */
354 /* ARGSUSED */
355 int
356 loioctl(ifp, cmd, data)
357 register struct ifnet *ifp;
358 u_long cmd;
359 caddr_t data;
360 {
361 register struct ifaddr *ifa;
362 register struct ifreq *ifr = (struct ifreq *)data;
363 register int error = 0;
364
365 switch (cmd) {
366
367 case SIOCSIFADDR:
368 ifp->if_flags |= IFF_UP;
369 ifp->if_drv_flags |= IFF_DRV_RUNNING;
370 ifa = (struct ifaddr *)data;
371 ifa->ifa_rtrequest = lortrequest;
372 /*
373 * Everything else is done at a higher level.
374 */
375 break;
376
377 case SIOCADDMULTI:
378 case SIOCDELMULTI:
379 if (ifr == 0) {
380 error = EAFNOSUPPORT; /* XXX */
381 break;
382 }
383 switch (ifr->ifr_addr.sa_family) {
384
385 #ifdef INET
386 case AF_INET:
387 break;
388 #endif
389 #ifdef INET6
390 case AF_INET6:
391 break;
392 #endif
393
394 default:
395 error = EAFNOSUPPORT;
396 break;
397 }
398 break;
399
400 case SIOCSIFMTU:
401 ifp->if_mtu = ifr->ifr_mtu;
402 break;
403
404 case SIOCSIFFLAGS:
405 break;
406
407 default:
408 error = EINVAL;
409 }
410 return (error);
411 }
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