xref: /netbsd-src/sys/net/if_loop.c (revision a24efa7dea9f1f56c3bdb15a927d3516792ace1c) 
1 /*	$NetBSD: if_loop.c,v 1.86 2016/04/28 01:37:17 knakahara 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 1.86 2016/04/28 01:37:17 knakahara 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 
87 #include <sys/cpu.h>
88 
89 #include <net/if.h>
90 #include <net/if_types.h>
91 #include <net/netisr.h>
92 #include <net/route.h>
93 
94 #ifdef	INET
95 #include <netinet/in.h>
96 #include <netinet/in_systm.h>
97 #include <netinet/in_var.h>
98 #include <netinet/in_offload.h>
99 #include <netinet/ip.h>
100 #endif
101 
102 #ifdef INET6
103 #ifndef INET
104 #include <netinet/in.h>
105 #endif
106 #include <netinet6/in6_var.h>
107 #include <netinet6/in6_offload.h>
108 #include <netinet/ip6.h>
109 #endif
110 
111 #ifdef MPLS
112 #include <netmpls/mpls.h>
113 #include <netmpls/mpls_var.h>
114 #endif
115 
116 #ifdef NETATALK
117 #include <netatalk/at.h>
118 #include <netatalk/at_var.h>
119 #endif
120 
121 #include <net/bpf.h>
122 
123 #if defined(LARGE_LOMTU)
124 #define LOMTU	(131072 +  MHLEN + MLEN)
125 #define LOMTU_MAX LOMTU
126 #else
127 #define	LOMTU	(32768 +  MHLEN + MLEN)
128 #define	LOMTU_MAX	(65536 +  MHLEN + MLEN)
129 #endif
130 
131 #ifdef ALTQ
132 static void	lostart(struct ifnet *);
133 #endif
134 
135 static int	loop_clone_create(struct if_clone *, int);
136 static int	loop_clone_destroy(struct ifnet *);
137 
138 static struct if_clone loop_cloner =
139     IF_CLONE_INITIALIZER("lo", loop_clone_create, loop_clone_destroy);
140 
141 void
142 loopattach(int n)
143 {
144 
145 	(void)loop_clone_create(&loop_cloner, 0);	/* lo0 always exists */
146 	if_clone_attach(&loop_cloner);
147 }
148 
149 static int
150 loop_clone_create(struct if_clone *ifc, int unit)
151 {
152 	struct ifnet *ifp;
153 
154 	ifp = if_alloc(IFT_LOOP);
155 
156 	if_initname(ifp, ifc->ifc_name, unit);
157 
158 	ifp->if_mtu = LOMTU;
159 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST | IFF_RUNNING;
160 	ifp->if_ioctl = loioctl;
161 	ifp->if_output = looutput;
162 #ifdef ALTQ
163 	ifp->if_start = lostart;
164 #endif
165 	ifp->if_type = IFT_LOOP;
166 	ifp->if_hdrlen = 0;
167 	ifp->if_addrlen = 0;
168 	ifp->if_dlt = DLT_NULL;
169 	IFQ_SET_READY(&ifp->if_snd);
170 	if (unit == 0)
171 		lo0ifp = ifp;
172 	if_attach(ifp);
173 	if_alloc_sadl(ifp);
174 	bpf_attach(ifp, DLT_NULL, sizeof(u_int));
175 #ifdef MBUFTRACE
176 	ifp->if_mowner = malloc(sizeof(struct mowner), M_DEVBUF,
177 	    M_WAITOK | M_ZERO);
178 	strlcpy(ifp->if_mowner->mo_name, ifp->if_xname,
179 	    sizeof(ifp->if_mowner->mo_name));
180 	MOWNER_ATTACH(ifp->if_mowner);
181 #endif
182 
183 	return (0);
184 }
185 
186 static int
187 loop_clone_destroy(struct ifnet *ifp)
188 {
189 
190 	if (ifp == lo0ifp)
191 		return (EPERM);
192 
193 #ifdef MBUFTRACE
194 	MOWNER_DETACH(ifp->if_mowner);
195 	free(ifp->if_mowner, M_DEVBUF);
196 #endif
197 
198 	bpf_detach(ifp);
199 	if_detach(ifp);
200 
201 	if_free(ifp);
202 
203 	return (0);
204 }
205 
206 int
207 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
208     const struct rtentry *rt)
209 {
210 	pktqueue_t *pktq = NULL;
211 	struct ifqueue *ifq = NULL;
212 	int s, isr = -1;
213 	int csum_flags;
214 	size_t pktlen;
215 
216 	MCLAIM(m, ifp->if_mowner);
217 #ifndef NET_MPSAFE
218 	KASSERT(KERNEL_LOCKED_P());
219 #endif
220 
221 	if ((m->m_flags & M_PKTHDR) == 0)
222 		panic("looutput: no header mbuf");
223 	if (ifp->if_flags & IFF_LOOPBACK)
224 		bpf_mtap_af(ifp, dst->sa_family, m);
225 	m->m_pkthdr.rcvif = ifp;
226 
227 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
228 		m_freem(m);
229 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
230 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
231 	}
232 
233 	pktlen = m->m_pkthdr.len;
234 	ifp->if_opackets++;
235 	ifp->if_obytes += pktlen;
236 
237 #ifdef ALTQ
238 	/*
239 	 * ALTQ on the loopback interface is just for debugging.  It's
240 	 * used only for loopback interfaces, not for a simplex interface.
241 	 */
242 	if ((ALTQ_IS_ENABLED(&ifp->if_snd) || TBR_IS_ENABLED(&ifp->if_snd)) &&
243 	    ifp->if_start == lostart) {
244 		int error;
245 
246 		/*
247 		 * If the queueing discipline needs packet classification,
248 		 * do it before prepending the link headers.
249 		 */
250 		IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
251 
252 		M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT);
253 		if (m == NULL)
254 			return (ENOBUFS);
255 		*(mtod(m, uint32_t *)) = dst->sa_family;
256 
257 		error = ifp->if_transmit(ifp, m);
258 		return (error);
259 	}
260 #endif /* ALTQ */
261 
262 	m_tag_delete_nonpersistent(m);
263 
264 #ifdef MPLS
265 	if (rt != NULL && rt_gettag(rt) != NULL &&
266 	    rt_gettag(rt)->sa_family == AF_MPLS &&
267 	    (m->m_flags & (M_MCAST | M_BCAST)) == 0) {
268 		union mpls_shim msh;
269 		msh.s_addr = MPLS_GETSADDR(rt);
270 		if (msh.shim.label != MPLS_LABEL_IMPLNULL) {
271 			ifq = &mplsintrq;
272 			isr = NETISR_MPLS;
273 		}
274 	}
275 	if (isr != NETISR_MPLS)
276 #endif
277 	switch (dst->sa_family) {
278 
279 #ifdef INET
280 	case AF_INET:
281 		csum_flags = m->m_pkthdr.csum_flags;
282 		KASSERT((csum_flags & ~(M_CSUM_IPv4|M_CSUM_UDPv4)) == 0);
283 		if (csum_flags != 0 && IN_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
284 			ip_undefer_csum(m, 0, csum_flags);
285 		}
286 		m->m_pkthdr.csum_flags = 0;
287 		pktq = ip_pktq;
288 		break;
289 #endif
290 #ifdef INET6
291 	case AF_INET6:
292 		csum_flags = m->m_pkthdr.csum_flags;
293 		KASSERT((csum_flags & ~M_CSUM_UDPv6) == 0);
294 		if (csum_flags != 0 &&
295 		    IN6_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
296 			ip6_undefer_csum(m, 0, csum_flags);
297 		}
298 		m->m_pkthdr.csum_flags = 0;
299 		m->m_flags |= M_LOOP;
300 		pktq = ip6_pktq;
301 		break;
302 #endif
303 #ifdef NETATALK
304 	case AF_APPLETALK:
305 	        ifq = &atintrq2;
306 		isr = NETISR_ATALK;
307 		break;
308 #endif
309 	default:
310 		printf("%s: can't handle af%d\n", ifp->if_xname,
311 		    dst->sa_family);
312 		m_freem(m);
313 		return (EAFNOSUPPORT);
314 	}
315 
316 	s = splnet();
317 	if (__predict_true(pktq)) {
318 		int error = 0;
319 
320 		if (__predict_true(pktq_enqueue(pktq, m, 0))) {
321 			ifp->if_ipackets++;
322 			ifp->if_ibytes += pktlen;
323 		} else {
324 			m_freem(m);
325 			error = ENOBUFS;
326 		}
327 		splx(s);
328 		return error;
329 	}
330 	if (IF_QFULL(ifq)) {
331 		IF_DROP(ifq);
332 		m_freem(m);
333 		splx(s);
334 		return (ENOBUFS);
335 	}
336 	IF_ENQUEUE(ifq, m);
337 	schednetisr(isr);
338 	ifp->if_ipackets++;
339 	ifp->if_ibytes += m->m_pkthdr.len;
340 	splx(s);
341 	return (0);
342 }
343 
344 #ifdef ALTQ
345 static void
346 lostart(struct ifnet *ifp)
347 {
348 	for (;;) {
349 		pktqueue_t *pktq = NULL;
350 		struct ifqueue *ifq = NULL;
351 		struct mbuf *m;
352 		size_t pktlen;
353 		uint32_t af;
354 		int s, isr = 0;
355 
356 		IFQ_DEQUEUE(&ifp->if_snd, m);
357 		if (m == NULL)
358 			return;
359 
360 		af = *(mtod(m, uint32_t *));
361 		m_adj(m, sizeof(uint32_t));
362 
363 		switch (af) {
364 #ifdef INET
365 		case AF_INET:
366 			pktq = ip_pktq;
367 			break;
368 #endif
369 #ifdef INET6
370 		case AF_INET6:
371 			m->m_flags |= M_LOOP;
372 			pktq = ip6_pktq;
373 			break;
374 #endif
375 #ifdef NETATALK
376 		case AF_APPLETALK:
377 			ifq = &atintrq2;
378 			isr = NETISR_ATALK;
379 			break;
380 #endif
381 		default:
382 			printf("%s: can't handle af%d\n", ifp->if_xname, af);
383 			m_freem(m);
384 			return;
385 		}
386 		pktlen = m->m_pkthdr.len;
387 
388 		s = splnet();
389 		if (__predict_true(pktq)) {
390 			if (__predict_false(pktq_enqueue(pktq, m, 0))) {
391 				m_freem(m);
392 				splx(s);
393 				return;
394 			}
395 			ifp->if_ipackets++;
396 			ifp->if_ibytes += pktlen;
397 			splx(s);
398 			continue;
399 		}
400 		if (IF_QFULL(ifq)) {
401 			IF_DROP(ifq);
402 			splx(s);
403 			m_freem(m);
404 			return;
405 		}
406 		IF_ENQUEUE(ifq, m);
407 		schednetisr(isr);
408 		ifp->if_ipackets++;
409 		ifp->if_ibytes += pktlen;
410 		splx(s);
411 	}
412 }
413 #endif /* ALTQ */
414 
415 /* ARGSUSED */
416 void
417 lortrequest(int cmd, struct rtentry *rt,
418     const struct rt_addrinfo *info)
419 {
420 
421 	if (rt)
422 		rt->rt_rmx.rmx_mtu = lo0ifp->if_mtu;
423 }
424 
425 /*
426  * Process an ioctl request.
427  */
428 /* ARGSUSED */
429 int
430 loioctl(struct ifnet *ifp, u_long cmd, void *data)
431 {
432 	struct ifaddr *ifa;
433 	struct ifreq *ifr = data;
434 	int error = 0;
435 
436 	switch (cmd) {
437 
438 	case SIOCINITIFADDR:
439 		ifp->if_flags |= IFF_UP;
440 		ifa = (struct ifaddr *)data;
441 		if (ifa != NULL)
442 			ifa->ifa_rtrequest = lortrequest;
443 		/*
444 		 * Everything else is done at a higher level.
445 		 */
446 		break;
447 
448 	case SIOCSIFMTU:
449 		if ((unsigned)ifr->ifr_mtu > LOMTU_MAX)
450 			error = EINVAL;
451 		else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET){
452 			error = 0;
453 		}
454 		break;
455 
456 	case SIOCADDMULTI:
457 	case SIOCDELMULTI:
458 		if (ifr == NULL) {
459 			error = EAFNOSUPPORT;		/* XXX */
460 			break;
461 		}
462 		switch (ifreq_getaddr(cmd, ifr)->sa_family) {
463 
464 #ifdef INET
465 		case AF_INET:
466 			break;
467 #endif
468 #ifdef INET6
469 		case AF_INET6:
470 			break;
471 #endif
472 
473 		default:
474 			error = EAFNOSUPPORT;
475 			break;
476 		}
477 		break;
478 
479 	default:
480 		error = ifioctl_common(ifp, cmd, data);
481 	}
482 	return (error);
483 }
484