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: releng/9.2/sys/net/if_loop.c 238876 2012-07-28 23:11:09Z bz $
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/mbuf.h>
46 #include <sys/module.h>
47 #include <machine/bus.h>
48 #include <sys/rman.h>
49 #include <sys/socket.h>
50 #include <sys/sockio.h>
51 #include <sys/sysctl.h>
52
53 #include <net/if.h>
54 #include <net/if_clone.h>
55 #include <net/if_types.h>
56 #include <net/netisr.h>
57 #include <net/route.h>
58 #include <net/bpf.h>
59 #include <net/vnet.h>
60
61 #ifdef INET
62 #include <netinet/in.h>
63 #include <netinet/in_var.h>
64 #endif
65
66 #ifdef IPX
67 #include <netipx/ipx.h>
68 #include <netipx/ipx_if.h>
69 #endif
70
71 #ifdef INET6
72 #ifndef INET
73 #include <netinet/in.h>
74 #endif
75 #include <netinet6/in6_var.h>
76 #include <netinet/ip6.h>
77 #endif
78
79 #ifdef NETATALK
80 #include <netatalk/at.h>
81 #include <netatalk/at_var.h>
82 #endif
83
84 #include <security/mac/mac_framework.h>
85
86 #ifdef TINY_LOMTU
87 #define LOMTU (1024+512)
88 #elif defined(LARGE_LOMTU)
89 #define LOMTU 131072
90 #else
91 #define LOMTU 16384
92 #endif
93
94 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
95 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
96 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
97 CSUM_PSEUDO_HDR | \
98 CSUM_IP_CHECKED | CSUM_IP_VALID | \
99 CSUM_SCTP_VALID)
100
101 int loioctl(struct ifnet *, u_long, caddr_t);
102 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
103 int looutput(struct ifnet *ifp, struct mbuf *m,
104 struct sockaddr *dst, struct route *ro);
105 static int lo_clone_create(struct if_clone *, int, caddr_t);
106 static void lo_clone_destroy(struct ifnet *);
107
108 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
109
110 #ifdef VIMAGE
111 static VNET_DEFINE(struct ifc_simple_data, lo_cloner_data);
112 static VNET_DEFINE(struct if_clone, lo_cloner);
113 #define V_lo_cloner_data VNET(lo_cloner_data)
114 #define V_lo_cloner VNET(lo_cloner)
115 #endif
116
117 IFC_SIMPLE_DECLARE(lo, 1);
118
119 static void
120 lo_clone_destroy(struct ifnet *ifp)
121 {
122
123 #ifndef VIMAGE
124 /* XXX: destroying lo0 will lead to panics. */
125 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
126 #endif
127
128 bpfdetach(ifp);
129 if_detach(ifp);
130 if_free(ifp);
131 }
132
133 static int
134 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
135 {
136 struct ifnet *ifp;
137
138 ifp = if_alloc(IFT_LOOP);
139 if (ifp == NULL)
140 return (ENOSPC);
141
142 if_initname(ifp, ifc->ifc_name, unit);
143 ifp->if_mtu = LOMTU;
144 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
145 ifp->if_ioctl = loioctl;
146 ifp->if_output = looutput;
147 ifp->if_snd.ifq_maxlen = ifqmaxlen;
148 ifp->if_capabilities = ifp->if_capenable =
149 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6;
150 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
151 if_attach(ifp);
152 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
153 if (V_loif == NULL)
154 V_loif = ifp;
155
156 return (0);
157 }
158
159 static void
160 vnet_loif_init(const void *unused __unused)
161 {
162
163 #ifdef VIMAGE
164 V_lo_cloner = lo_cloner;
165 V_lo_cloner_data = lo_cloner_data;
166 V_lo_cloner.ifc_data = &V_lo_cloner_data;
167 if_clone_attach(&V_lo_cloner);
168 #else
169 if_clone_attach(&lo_cloner);
170 #endif
171 }
172 VNET_SYSINIT(vnet_loif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
173 vnet_loif_init, NULL);
174
175 #ifdef VIMAGE
176 static void
177 vnet_loif_uninit(const void *unused __unused)
178 {
179
180 if_clone_detach(&V_lo_cloner);
181 V_loif = NULL;
182 }
183 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
184 vnet_loif_uninit, NULL);
185 #endif
186
187 static int
188 loop_modevent(module_t mod, int type, void *data)
189 {
190
191 switch (type) {
192 case MOD_LOAD:
193 break;
194
195 case MOD_UNLOAD:
196 printf("loop module unload - not possible for this module type\n");
197 return (EINVAL);
198
199 default:
200 return (EOPNOTSUPP);
201 }
202 return (0);
203 }
204
205 static moduledata_t loop_mod = {
206 "if_lo",
207 loop_modevent,
208 0
209 };
210
211 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
212
213 int
214 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
215 struct route *ro)
216 {
217 u_int32_t af;
218 struct rtentry *rt = NULL;
219 #ifdef MAC
220 int error;
221 #endif
222
223 M_ASSERTPKTHDR(m); /* check if we have the packet header */
224
225 if (ro != NULL)
226 rt = ro->ro_rt;
227 #ifdef MAC
228 error = mac_ifnet_check_transmit(ifp, m);
229 if (error) {
230 m_freem(m);
231 return (error);
232 }
233 #endif
234
235 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
236 m_freem(m);
237 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
238 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
239 }
240
241 ifp->if_opackets++;
242 ifp->if_obytes += m->m_pkthdr.len;
243
244 /* BPF writes need to be handled specially. */
245 if (dst->sa_family == AF_UNSPEC) {
246 bcopy(dst->sa_data, &af, sizeof(af));
247 dst->sa_family = af;
248 }
249
250 #if 1 /* XXX */
251 switch (dst->sa_family) {
252 case AF_INET:
253 if (ifp->if_capenable & IFCAP_RXCSUM) {
254 m->m_pkthdr.csum_data = 0xffff;
255 m->m_pkthdr.csum_flags = LO_CSUM_SET;
256 }
257 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
258 break;
259 case AF_INET6:
260 #if 0
261 /*
262 * XXX-BZ for now always claim the checksum is good despite
263 * any interface flags. This is a workaround for 9.1-R and
264 * a proper solution ought to be sought later.
265 */
266 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
267 m->m_pkthdr.csum_data = 0xffff;
268 m->m_pkthdr.csum_flags = LO_CSUM_SET;
269 }
270 #else
271 m->m_pkthdr.csum_data = 0xffff;
272 m->m_pkthdr.csum_flags = LO_CSUM_SET;
273 #endif
274 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
275 break;
276 case AF_IPX:
277 case AF_APPLETALK:
278 break;
279 default:
280 printf("looutput: af=%d unexpected\n", dst->sa_family);
281 m_freem(m);
282 return (EAFNOSUPPORT);
283 }
284 #endif
285 return (if_simloop(ifp, m, dst->sa_family, 0));
286 }
287
288 /*
289 * if_simloop()
290 *
291 * This function is to support software emulation of hardware loopback,
292 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
293 * hear their own broadcasts, we create a copy of the packet that we
294 * would normally receive via a hardware loopback.
295 *
296 * This function expects the packet to include the media header of length hlen.
297 */
298 int
299 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
300 {
301 int isr;
302
303 M_ASSERTPKTHDR(m);
304 m_tag_delete_nonpersistent(m);
305 m->m_pkthdr.rcvif = ifp;
306
307 #ifdef MAC
308 mac_ifnet_create_mbuf(ifp, m);
309 #endif
310
311 /*
312 * Let BPF see incoming packet in the following manner:
313 * - Emulated packet loopback for a simplex interface
314 * (net/if_ethersubr.c)
315 * -> passes it to ifp's BPF
316 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
317 * -> not passes it to any BPF
318 * - Normal packet loopback from myself to myself (net/if_loop.c)
319 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
320 */
321 if (hlen > 0) {
322 if (bpf_peers_present(ifp->if_bpf)) {
323 bpf_mtap(ifp->if_bpf, m);
324 }
325 } else {
326 if (bpf_peers_present(V_loif->if_bpf)) {
327 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
328 /* XXX beware sizeof(af) != 4 */
329 u_int32_t af1 = af;
330
331 /*
332 * We need to prepend the address family.
333 */
334 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
335 }
336 }
337 }
338
339 /* Strip away media header */
340 if (hlen > 0) {
341 m_adj(m, hlen);
342 #ifndef __NO_STRICT_ALIGNMENT
343 /*
344 * Some archs do not like unaligned data, so
345 * we move data down in the first mbuf.
346 */
347 if (mtod(m, vm_offset_t) & 3) {
348 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
349 bcopy(m->m_data,
350 (char *)(mtod(m, vm_offset_t)
351 - (mtod(m, vm_offset_t) & 3)),
352 m->m_len);
353 m->m_data -= (mtod(m,vm_offset_t) & 3);
354 }
355 #endif
356 }
357
358 /* Deliver to upper layer protocol */
359 switch (af) {
360 #ifdef INET
361 case AF_INET:
362 isr = NETISR_IP;
363 break;
364 #endif
365 #ifdef INET6
366 case AF_INET6:
367 m->m_flags |= M_LOOP;
368 isr = NETISR_IPV6;
369 break;
370 #endif
371 #ifdef IPX
372 case AF_IPX:
373 isr = NETISR_IPX;
374 break;
375 #endif
376 #ifdef NETATALK
377 case AF_APPLETALK:
378 isr = NETISR_ATALK2;
379 break;
380 #endif
381 default:
382 printf("if_simloop: can't handle af=%d\n", af);
383 m_freem(m);
384 return (EAFNOSUPPORT);
385 }
386 ifp->if_ipackets++;
387 ifp->if_ibytes += m->m_pkthdr.len;
388 netisr_queue(isr, m); /* mbuf is free'd on failure. */
389 return (0);
390 }
391
392 /* ARGSUSED */
393 static void
394 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
395 {
396
397 RT_LOCK_ASSERT(rt);
398 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
399 }
400
401 /*
402 * Process an ioctl request.
403 */
404 /* ARGSUSED */
405 int
406 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
407 {
408 struct ifaddr *ifa;
409 struct ifreq *ifr = (struct ifreq *)data;
410 int error = 0, mask;
411
412 switch (cmd) {
413 case SIOCSIFADDR:
414 ifp->if_flags |= IFF_UP;
415 ifp->if_drv_flags |= IFF_DRV_RUNNING;
416 ifa = (struct ifaddr *)data;
417 ifa->ifa_rtrequest = lortrequest;
418 /*
419 * Everything else is done at a higher level.
420 */
421 break;
422
423 case SIOCADDMULTI:
424 case SIOCDELMULTI:
425 if (ifr == 0) {
426 error = EAFNOSUPPORT; /* XXX */
427 break;
428 }
429 switch (ifr->ifr_addr.sa_family) {
430
431 #ifdef INET
432 case AF_INET:
433 break;
434 #endif
435 #ifdef INET6
436 case AF_INET6:
437 break;
438 #endif
439
440 default:
441 error = EAFNOSUPPORT;
442 break;
443 }
444 break;
445
446 case SIOCSIFMTU:
447 ifp->if_mtu = ifr->ifr_mtu;
448 break;
449
450 case SIOCSIFFLAGS:
451 break;
452
453 case SIOCSIFCAP:
454 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
455 if ((mask & IFCAP_RXCSUM) != 0)
456 ifp->if_capenable ^= IFCAP_RXCSUM;
457 if ((mask & IFCAP_TXCSUM) != 0)
458 ifp->if_capenable ^= IFCAP_TXCSUM;
459 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
460 #if 0
461 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
462 #else
463 error = EOPNOTSUPP;
464 break;
465 #endif
466 }
467 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
468 #if 0
469 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
470 #else
471 error = EOPNOTSUPP;
472 break;
473 #endif
474 }
475 ifp->if_hwassist = 0;
476 if (ifp->if_capenable & IFCAP_TXCSUM)
477 ifp->if_hwassist = LO_CSUM_FEATURES;
478 #if 0
479 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
480 ifp->if_hwassist |= LO_CSUM_FEATURES6;
481 #endif
482 break;
483
484 default:
485 error = EINVAL;
486 }
487 return (error);
488 }
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