1 /* $NetBSD: if_loop.c,v 1.118 2022/09/04 23:34:51 thorpej Exp $ */
2
3 /*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * Copyright (c) 1982, 1986, 1993
34 * The Regents of the University of California. All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 * notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 * notice, this list of conditions and the following disclaimer in the
43 * documentation and/or other materials provided with the distribution.
44 * 3. Neither the name of the University nor the names of its contributors
45 * may be used to endorse or promote products derived from this software
46 * without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 *
60 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
61 */
62
63 /*
64 * Loopback interface driver for protocol testing and timing.
65 */
66
67 #include <sys/cdefs.h>
68 __KERNEL_RCSID(0, "$NetBSD: if_loop.c,v 1.118 2022/09/04 23:34:51 thorpej Exp $");
69
70 #ifdef _KERNEL_OPT
71 #include "opt_inet.h"
72 #include "opt_atalk.h"
73 #include "opt_mbuftrace.h"
74 #include "opt_mpls.h"
75 #include "opt_net_mpsafe.h"
76 #endif
77
78 #include <sys/param.h>
79 #include <sys/systm.h>
80 #include <sys/kernel.h>
81 #include <sys/mbuf.h>
82 #include <sys/socket.h>
83 #include <sys/errno.h>
84 #include <sys/ioctl.h>
85 #include <sys/time.h>
86 #include <sys/device.h>
87 #include <sys/module.h>
88
89 #include <sys/cpu.h>
90
91 #include <net/if.h>
92 #include <net/if_types.h>
93 #include <net/route.h>
94
95 #ifdef INET
96 #include <netinet/in.h>
97 #include <netinet/in_systm.h>
98 #include <netinet/in_var.h>
99 #include <netinet/in_offload.h>
100 #include <netinet/ip.h>
101 #include <netinet/ip_var.h>
102 #endif
103
104 #ifdef INET6
105 #ifndef INET
106 #include <netinet/in.h>
107 #endif
108 #include <netinet6/in6_var.h>
109 #include <netinet6/in6_offload.h>
110 #include <netinet/ip6.h>
111 #endif
112
113 #ifdef MPLS
114 #include <netmpls/mpls.h>
115 #include <netmpls/mpls_var.h>
116 #endif
117
118 #ifdef NETATALK
119 #include <netatalk/at.h>
120 #include <netatalk/at_var.h>
121 #endif
122
123 #include <net/bpf.h>
124
125 #if defined(LARGE_LOMTU)
126 #define LOMTU (131072 + MHLEN + MLEN)
127 #define LOMTU_MAX LOMTU
128 #else
129 #define LOMTU (32768 + MHLEN + MLEN)
130 #define LOMTU_MAX (65536 + MHLEN + MLEN)
131 #endif
132
133 #ifdef ALTQ
134 static void lostart(struct ifnet *);
135 #endif
136
137 static int loop_clone_create(struct if_clone *, int);
138 static int loop_clone_destroy(struct ifnet *);
139
140 static void loop_rtrequest(int, struct rtentry *, const struct rt_addrinfo *);
141
142 static struct if_clone loop_cloner =
143 IF_CLONE_INITIALIZER("lo", loop_clone_create, loop_clone_destroy);
144
145 void
loopattach(int n)146 loopattach(int n)
147 {
148
149 #ifndef _MODULE
150 loop_clone_create(&loop_cloner, 0); /* lo0 always exists */
151 #endif
152 }
153
154 void
loopinit(void)155 loopinit(void)
156 {
157
158 if (lo0ifp != NULL) /* can happen in rump kernel */
159 return;
160
161 #ifdef _MODULE
162 loop_clone_create(&loop_cloner, 0); /* lo0 always exists */
163 #endif
164 if_clone_attach(&loop_cloner);
165 }
166
167 static int
loopdetach(void)168 loopdetach(void)
169 {
170 /* no detach for now; we don't allow lo0 to be deleted */
171 return EBUSY;
172 }
173
174 static int
loop_clone_create(struct if_clone * ifc,int unit)175 loop_clone_create(struct if_clone *ifc, int unit)
176 {
177 struct ifnet *ifp;
178
179 ifp = if_alloc(IFT_LOOP);
180
181 if_initname(ifp, ifc->ifc_name, unit);
182
183 ifp->if_mtu = LOMTU;
184 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
185 #ifdef NET_MPSAFE
186 ifp->if_extflags = IFEF_MPSAFE;
187 #endif
188 ifp->if_ioctl = loioctl;
189 ifp->if_output = looutput;
190 #ifdef ALTQ
191 ifp->if_start = lostart;
192 #endif
193 ifp->if_type = IFT_LOOP;
194 ifp->if_hdrlen = 0;
195 ifp->if_addrlen = 0;
196 ifp->if_dlt = DLT_NULL;
197 IFQ_SET_READY(&ifp->if_snd);
198 if (unit == 0)
199 lo0ifp = ifp;
200 if_initialize(ifp);
201 ifp->if_link_state = LINK_STATE_UP;
202 if_alloc_sadl(ifp);
203 bpf_attach(ifp, DLT_NULL, sizeof(u_int));
204 #ifdef MBUFTRACE
205 ifp->if_mowner = malloc(sizeof(struct mowner), M_DEVBUF,
206 M_WAITOK | M_ZERO);
207 strlcpy(ifp->if_mowner->mo_name, ifp->if_xname,
208 sizeof(ifp->if_mowner->mo_name));
209 MOWNER_ATTACH(ifp->if_mowner);
210 #endif
211
212 ifp->if_flags |= IFF_RUNNING;
213 if_register(ifp);
214
215 return (0);
216 }
217
218 static int
loop_clone_destroy(struct ifnet * ifp)219 loop_clone_destroy(struct ifnet *ifp)
220 {
221
222 if (ifp == lo0ifp)
223 return (EPERM);
224
225 ifp->if_flags &= ~IFF_RUNNING;
226
227 #ifdef MBUFTRACE
228 MOWNER_DETACH(ifp->if_mowner);
229 free(ifp->if_mowner, M_DEVBUF);
230 #endif
231
232 bpf_detach(ifp);
233 if_detach(ifp);
234
235 if_free(ifp);
236
237 return (0);
238 }
239
240 int
looutput(struct ifnet * ifp,struct mbuf * m,const struct sockaddr * dst,const struct rtentry * rt)241 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
242 const struct rtentry *rt)
243 {
244 pktqueue_t *pktq = NULL;
245 int s;
246 int csum_flags;
247 int error = 0;
248 size_t pktlen;
249
250 MCLAIM(m, ifp->if_mowner);
251
252 KERNEL_LOCK_UNLESS_NET_MPSAFE();
253
254 if ((m->m_flags & M_PKTHDR) == 0)
255 panic("looutput: no header mbuf");
256 if (ifp->if_flags & IFF_LOOPBACK)
257 bpf_mtap_af(ifp, dst->sa_family, m, BPF_D_OUT);
258 m_set_rcvif(m, ifp);
259
260 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
261 m_freem(m);
262 error = (rt->rt_flags & RTF_BLACKHOLE ? 0 :
263 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
264 goto out;
265 }
266
267 pktlen = m->m_pkthdr.len;
268
269 if_statadd2(ifp, if_opackets, 1, if_obytes, pktlen);
270
271 #ifdef ALTQ
272 /*
273 * ALTQ on the loopback interface is just for debugging. It's
274 * used only for loopback interfaces, not for a simplex interface.
275 */
276 if ((ALTQ_IS_ENABLED(&ifp->if_snd) || TBR_IS_ENABLED(&ifp->if_snd)) &&
277 ifp->if_start == lostart) {
278 /*
279 * If the queueing discipline needs packet classification,
280 * do it before prepending the link headers.
281 */
282 IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
283
284 M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT);
285 if (m == NULL) {
286 if_statinc(ifp, if_oerrors);
287 error = ENOBUFS;
288 goto out;
289 }
290 *(mtod(m, uint32_t *)) = dst->sa_family;
291
292 error = if_transmit_lock(ifp, m);
293 goto out;
294 }
295 #endif /* ALTQ */
296
297 m_tag_delete_chain(m);
298
299 #ifdef MPLS
300 bool is_mpls = false;
301 if (rt != NULL && rt_gettag(rt) != NULL &&
302 rt_gettag(rt)->sa_family == AF_MPLS &&
303 (m->m_flags & (M_MCAST | M_BCAST)) == 0) {
304 union mpls_shim msh;
305 msh.s_addr = MPLS_GETSADDR(rt);
306 if (msh.shim.label != MPLS_LABEL_IMPLNULL) {
307 is_mpls = true;
308 pktq = mpls_pktq;
309 }
310 }
311 if (!is_mpls)
312 #endif
313 switch (dst->sa_family) {
314
315 #ifdef INET
316 case AF_INET:
317 csum_flags = m->m_pkthdr.csum_flags;
318 KASSERT((csum_flags & ~(M_CSUM_IPv4|M_CSUM_UDPv4)) == 0);
319 if (csum_flags != 0 && IN_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
320 in_undefer_cksum(m, 0, csum_flags);
321 m->m_pkthdr.csum_flags = 0;
322 } else {
323 /*
324 * Do nothing. Pass M_CSUM_IPv4 and M_CSUM_UDPv4 as
325 * they are to tell those are calculated and good.
326 */
327 }
328 pktq = ip_pktq;
329 break;
330 #endif
331 #ifdef INET6
332 case AF_INET6:
333 csum_flags = m->m_pkthdr.csum_flags;
334 KASSERT((csum_flags & ~M_CSUM_UDPv6) == 0);
335 if (csum_flags != 0 &&
336 IN6_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
337 in6_undefer_cksum(m, 0, csum_flags);
338 m->m_pkthdr.csum_flags = 0;
339 } else {
340 /*
341 * Do nothing. Pass M_CSUM_UDPv6 as
342 * they are to tell those are calculated and good.
343 */
344 }
345 m->m_flags |= M_LOOP;
346 pktq = ip6_pktq;
347 break;
348 #endif
349 #ifdef NETATALK
350 case AF_APPLETALK:
351 pktq = at_pktq2;
352 break;
353 #endif
354 default:
355 printf("%s: can't handle af%d\n", ifp->if_xname,
356 dst->sa_family);
357 m_freem(m);
358 error = EAFNOSUPPORT;
359 goto out;
360 }
361
362 KASSERT(pktq != NULL);
363
364 error = 0;
365 s = splnet();
366 if (__predict_true(pktq_enqueue(pktq, m, 0))) {
367 if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen);
368 } else {
369 m_freem(m);
370 if_statinc(ifp, if_oerrors);
371 error = ENOBUFS;
372 }
373 splx(s);
374 out:
375 KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
376 return error;
377 }
378
379 #ifdef ALTQ
380 static void
lostart(struct ifnet * ifp)381 lostart(struct ifnet *ifp)
382 {
383 for (;;) {
384 pktqueue_t *pktq = NULL;
385 struct mbuf *m;
386 size_t pktlen;
387 uint32_t af;
388 int s;
389
390 IFQ_DEQUEUE(&ifp->if_snd, m);
391 if (m == NULL)
392 return;
393
394 af = *(mtod(m, uint32_t *));
395 m_adj(m, sizeof(uint32_t));
396
397 switch (af) {
398 #ifdef INET
399 case AF_INET:
400 pktq = ip_pktq;
401 break;
402 #endif
403 #ifdef INET6
404 case AF_INET6:
405 m->m_flags |= M_LOOP;
406 pktq = ip6_pktq;
407 break;
408 #endif
409 #ifdef NETATALK
410 case AF_APPLETALK:
411 pktq = at_pktq2;
412 break;
413 #endif
414 default:
415 printf("%s: can't handle af%d\n", ifp->if_xname, af);
416 m_freem(m);
417 return;
418 }
419 pktlen = m->m_pkthdr.len;
420
421 KASSERT(pktq != NULL);
422
423 s = splnet();
424 if (__predict_false(pktq_enqueue(pktq, m, 0))) {
425 m_freem(m);
426 splx(s);
427 return;
428 }
429 if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen);
430 splx(s);
431 }
432 }
433 #endif /* ALTQ */
434
435 /* ARGSUSED */
436 static void
loop_rtrequest(int cmd,struct rtentry * rt,const struct rt_addrinfo * info)437 loop_rtrequest(int cmd, struct rtentry *rt,
438 const struct rt_addrinfo *info)
439 {
440
441 if (rt)
442 rt->rt_rmx.rmx_mtu = lo0ifp->if_mtu;
443 }
444
445 /*
446 * Process an ioctl request.
447 */
448 /* ARGSUSED */
449 int
loioctl(struct ifnet * ifp,u_long cmd,void * data)450 loioctl(struct ifnet *ifp, u_long cmd, void *data)
451 {
452 struct ifaddr *ifa;
453 struct ifreq *ifr = data;
454 int error = 0;
455
456 switch (cmd) {
457
458 case SIOCINITIFADDR:
459 ifp->if_flags |= IFF_UP;
460 ifa = (struct ifaddr *)data;
461 if (ifa != NULL)
462 ifa->ifa_rtrequest = loop_rtrequest;
463 /*
464 * Everything else is done at a higher level.
465 */
466 break;
467
468 case SIOCSIFMTU:
469 if ((unsigned)ifr->ifr_mtu > LOMTU_MAX)
470 error = EINVAL;
471 else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET){
472 error = 0;
473 }
474 break;
475
476 case SIOCADDMULTI:
477 case SIOCDELMULTI:
478 if (ifr == NULL) {
479 error = EAFNOSUPPORT; /* XXX */
480 break;
481 }
482 switch (ifreq_getaddr(cmd, ifr)->sa_family) {
483
484 #ifdef INET
485 case AF_INET:
486 break;
487 #endif
488 #ifdef INET6
489 case AF_INET6:
490 break;
491 #endif
492
493 default:
494 error = EAFNOSUPPORT;
495 break;
496 }
497 break;
498
499 default:
500 error = ifioctl_common(ifp, cmd, data);
501 }
502 return (error);
503 }
504
505 /*
506 * Module infrastructure
507 */
508 #include "if_module.h"
509
510 IF_MODULE(MODULE_CLASS_DRIVER, loop, NULL)
511