xref: /netbsd-src/sys/net/if_loop.c (revision f89f6560d453f5e37386cc7938c072d2f528b9fa) 
1 /*	$NetBSD: if_loop.c,v 1.81 2015/04/03 07:55:18 ozaki-r 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 1.81 2015/04/03 07:55:18 ozaki-r Exp $");
69 
70 #include "opt_inet.h"
71 #include "opt_atalk.h"
72 #include "opt_ipx.h"
73 #include "opt_mbuftrace.h"
74 #include "opt_mpls.h"
75 #include "opt_net_mpsafe.h"
76 
77 #include <sys/param.h>
78 #include <sys/systm.h>
79 #include <sys/kernel.h>
80 #include <sys/mbuf.h>
81 #include <sys/socket.h>
82 #include <sys/errno.h>
83 #include <sys/ioctl.h>
84 #include <sys/time.h>
85 
86 #include <sys/cpu.h>
87 
88 #include <net/if.h>
89 #include <net/if_types.h>
90 #include <net/netisr.h>
91 #include <net/route.h>
92 
93 #ifdef	INET
94 #include <netinet/in.h>
95 #include <netinet/in_systm.h>
96 #include <netinet/in_var.h>
97 #include <netinet/in_offload.h>
98 #include <netinet/ip.h>
99 #endif
100 
101 #ifdef INET6
102 #ifndef INET
103 #include <netinet/in.h>
104 #endif
105 #include <netinet6/in6_var.h>
106 #include <netinet6/in6_offload.h>
107 #include <netinet/ip6.h>
108 #endif
109 
110 #ifdef IPX
111 #include <netipx/ipx.h>
112 #include <netipx/ipx_if.h>
113 #endif
114 
115 #ifdef MPLS
116 #include <netmpls/mpls.h>
117 #include <netmpls/mpls_var.h>
118 #endif
119 
120 #ifdef NETATALK
121 #include <netatalk/at.h>
122 #include <netatalk/at_var.h>
123 #endif
124 
125 #include <net/bpf.h>
126 
127 #if defined(LARGE_LOMTU)
128 #define LOMTU	(131072 +  MHLEN + MLEN)
129 #define LOMTU_MAX LOMTU
130 #else
131 #define	LOMTU	(32768 +  MHLEN + MLEN)
132 #define	LOMTU_MAX	(65536 +  MHLEN + MLEN)
133 #endif
134 
135 #ifdef ALTQ
136 static void	lostart(struct ifnet *);
137 #endif
138 
139 static int	loop_clone_create(struct if_clone *, int);
140 static int	loop_clone_destroy(struct ifnet *);
141 
142 static struct if_clone loop_cloner =
143     IF_CLONE_INITIALIZER("lo", loop_clone_create, loop_clone_destroy);
144 
145 void
146 loopattach(int n)
147 {
148 
149 	(void)loop_clone_create(&loop_cloner, 0);	/* lo0 always exists */
150 	if_clone_attach(&loop_cloner);
151 }
152 
153 static int
154 loop_clone_create(struct if_clone *ifc, int unit)
155 {
156 	struct ifnet *ifp;
157 
158 	ifp = if_alloc(IFT_LOOP);
159 
160 	if_initname(ifp, ifc->ifc_name, unit);
161 
162 	ifp->if_mtu = LOMTU;
163 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST | IFF_RUNNING;
164 	ifp->if_ioctl = loioctl;
165 	ifp->if_output = looutput;
166 #ifdef ALTQ
167 	ifp->if_start = lostart;
168 #endif
169 	ifp->if_type = IFT_LOOP;
170 	ifp->if_hdrlen = 0;
171 	ifp->if_addrlen = 0;
172 	ifp->if_dlt = DLT_NULL;
173 	IFQ_SET_READY(&ifp->if_snd);
174 	if (unit == 0)
175 		lo0ifp = ifp;
176 	if_attach(ifp);
177 	if_alloc_sadl(ifp);
178 	bpf_attach(ifp, DLT_NULL, sizeof(u_int));
179 #ifdef MBUFTRACE
180 	ifp->if_mowner = malloc(sizeof(struct mowner), M_DEVBUF,
181 	    M_WAITOK | M_ZERO);
182 	strlcpy(ifp->if_mowner->mo_name, ifp->if_xname,
183 	    sizeof(ifp->if_mowner->mo_name));
184 	MOWNER_ATTACH(ifp->if_mowner);
185 #endif
186 
187 	return (0);
188 }
189 
190 static int
191 loop_clone_destroy(struct ifnet *ifp)
192 {
193 
194 	if (ifp == lo0ifp)
195 		return (EPERM);
196 
197 #ifdef MBUFTRACE
198 	MOWNER_DETACH(ifp->if_mowner);
199 	free(ifp->if_mowner, M_DEVBUF);
200 #endif
201 
202 	bpf_detach(ifp);
203 	if_detach(ifp);
204 
205 	if_free(ifp);
206 
207 	return (0);
208 }
209 
210 int
211 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
212     struct rtentry *rt)
213 {
214 	pktqueue_t *pktq = NULL;
215 	struct ifqueue *ifq = NULL;
216 	int s, isr = -1;
217 	int csum_flags;
218 	size_t pktlen;
219 
220 	MCLAIM(m, ifp->if_mowner);
221 #ifndef NET_MPSAFE
222 	KASSERT(KERNEL_LOCKED_P());
223 #endif
224 
225 	if ((m->m_flags & M_PKTHDR) == 0)
226 		panic("looutput: no header mbuf");
227 	if (ifp->if_flags & IFF_LOOPBACK)
228 		bpf_mtap_af(ifp, dst->sa_family, m);
229 	m->m_pkthdr.rcvif = ifp;
230 
231 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
232 		m_freem(m);
233 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
234 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
235 	}
236 
237 	pktlen = m->m_pkthdr.len;
238 	ifp->if_opackets++;
239 	ifp->if_obytes += pktlen;
240 
241 #ifdef ALTQ
242 	/*
243 	 * ALTQ on the loopback interface is just for debugging.  It's
244 	 * used only for loopback interfaces, not for a simplex interface.
245 	 */
246 	if ((ALTQ_IS_ENABLED(&ifp->if_snd) || TBR_IS_ENABLED(&ifp->if_snd)) &&
247 	    ifp->if_start == lostart) {
248 		struct altq_pktattr pktattr;
249 		int error;
250 
251 		/*
252 		 * If the queueing discipline needs packet classification,
253 		 * do it before prepending the link headers.
254 		 */
255 		IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family, &pktattr);
256 
257 		M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT);
258 		if (m == NULL)
259 			return (ENOBUFS);
260 		*(mtod(m, uint32_t *)) = dst->sa_family;
261 
262 		s = splnet();
263 		IFQ_ENQUEUE(&ifp->if_snd, m, &pktattr, error);
264 		(*ifp->if_start)(ifp);
265 		splx(s);
266 		return (error);
267 	}
268 #endif /* ALTQ */
269 
270 	m_tag_delete_nonpersistent(m);
271 
272 #ifdef MPLS
273 	if (rt != NULL && rt_gettag(rt) != NULL &&
274 	    rt_gettag(rt)->sa_family == AF_MPLS &&
275 	    (m->m_flags & (M_MCAST | M_BCAST)) == 0) {
276 		union mpls_shim msh;
277 		msh.s_addr = MPLS_GETSADDR(rt);
278 		if (msh.shim.label != MPLS_LABEL_IMPLNULL) {
279 			ifq = &mplsintrq;
280 			isr = NETISR_MPLS;
281 		}
282 	}
283 	if (isr != NETISR_MPLS)
284 #endif
285 	switch (dst->sa_family) {
286 
287 #ifdef INET
288 	case AF_INET:
289 		csum_flags = m->m_pkthdr.csum_flags;
290 		KASSERT((csum_flags & ~(M_CSUM_IPv4|M_CSUM_UDPv4)) == 0);
291 		if (csum_flags != 0 && IN_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
292 			ip_undefer_csum(m, 0, csum_flags);
293 		}
294 		m->m_pkthdr.csum_flags = 0;
295 		pktq = ip_pktq;
296 		break;
297 #endif
298 #ifdef INET6
299 	case AF_INET6:
300 		csum_flags = m->m_pkthdr.csum_flags;
301 		KASSERT((csum_flags & ~M_CSUM_UDPv6) == 0);
302 		if (csum_flags != 0 &&
303 		    IN6_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
304 			ip6_undefer_csum(m, 0, csum_flags);
305 		}
306 		m->m_pkthdr.csum_flags = 0;
307 		m->m_flags |= M_LOOP;
308 		pktq = ip6_pktq;
309 		break;
310 #endif
311 #ifdef IPX
312 	case AF_IPX:
313 		ifq = &ipxintrq;
314 		isr = NETISR_IPX;
315 		break;
316 #endif
317 #ifdef NETATALK
318 	case AF_APPLETALK:
319 	        ifq = &atintrq2;
320 		isr = NETISR_ATALK;
321 		break;
322 #endif
323 	default:
324 		printf("%s: can't handle af%d\n", ifp->if_xname,
325 		    dst->sa_family);
326 		m_freem(m);
327 		return (EAFNOSUPPORT);
328 	}
329 
330 	s = splnet();
331 	if (__predict_true(pktq)) {
332 		int error = 0;
333 
334 		if (__predict_true(pktq_enqueue(pktq, m, 0))) {
335 			ifp->if_ipackets++;
336 			ifp->if_ibytes += pktlen;
337 		} else {
338 			m_freem(m);
339 			error = ENOBUFS;
340 		}
341 		splx(s);
342 		return error;
343 	}
344 	if (IF_QFULL(ifq)) {
345 		IF_DROP(ifq);
346 		m_freem(m);
347 		splx(s);
348 		return (ENOBUFS);
349 	}
350 	IF_ENQUEUE(ifq, m);
351 	schednetisr(isr);
352 	ifp->if_ipackets++;
353 	ifp->if_ibytes += m->m_pkthdr.len;
354 	splx(s);
355 	return (0);
356 }
357 
358 #ifdef ALTQ
359 static void
360 lostart(struct ifnet *ifp)
361 {
362 	for (;;) {
363 		pktqueue_t *pktq = NULL;
364 		struct ifqueue *ifq = NULL;
365 		struct mbuf *m;
366 		size_t pktlen;
367 		uint32_t af;
368 		int s, isr = 0;
369 
370 		IFQ_DEQUEUE(&ifp->if_snd, m);
371 		if (m == NULL)
372 			return;
373 
374 		af = *(mtod(m, uint32_t *));
375 		m_adj(m, sizeof(uint32_t));
376 
377 		switch (af) {
378 #ifdef INET
379 		case AF_INET:
380 			pktq = ip_pktq;
381 			break;
382 #endif
383 #ifdef INET6
384 		case AF_INET6:
385 			m->m_flags |= M_LOOP;
386 			pktq = ip6_pktq;
387 			break;
388 #endif
389 #ifdef IPX
390 		case AF_IPX:
391 			ifq = &ipxintrq;
392 			isr = NETISR_IPX;
393 			break;
394 #endif
395 #ifdef NETATALK
396 		case AF_APPLETALK:
397 			ifq = &atintrq2;
398 			isr = NETISR_ATALK;
399 			break;
400 #endif
401 		default:
402 			printf("%s: can't handle af%d\n", ifp->if_xname, af);
403 			m_freem(m);
404 			return;
405 		}
406 		pktlen = m->m_pkthdr.len;
407 
408 		s = splnet();
409 		if (__predict_true(pktq)) {
410 			if (__predict_false(pktq_enqueue(pktq, m, 0))) {
411 				m_freem(m);
412 				splx(s);
413 				return;
414 			}
415 			ifp->if_ipackets++;
416 			ifp->if_ibytes += pktlen;
417 			splx(s);
418 			continue;
419 		}
420 		if (IF_QFULL(ifq)) {
421 			IF_DROP(ifq);
422 			splx(s);
423 			m_freem(m);
424 			return;
425 		}
426 		IF_ENQUEUE(ifq, m);
427 		schednetisr(isr);
428 		ifp->if_ipackets++;
429 		ifp->if_ibytes += pktlen;
430 		splx(s);
431 	}
432 }
433 #endif /* ALTQ */
434 
435 /* ARGSUSED */
436 void
437 lortrequest(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
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 = lortrequest;
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