xref: /netbsd-src/sys/net/if_loop.c (revision 6a493d6bc668897c91594964a732d38505b70cbb)
1 /*	$NetBSD: if_loop.c,v 1.76 2013/03/01 18:25:56 joerg 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 1.76 2013/03/01 18:25:56 joerg 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 
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 	free(ifp, M_DEVBUF);
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 	int s, isr = -1;
215 	struct ifqueue *ifq = NULL;
216 	int csum_flags;
217 
218 	MCLAIM(m, ifp->if_mowner);
219 	if ((m->m_flags & M_PKTHDR) == 0)
220 		panic("looutput: no header mbuf");
221 	if (ifp->if_flags & IFF_LOOPBACK)
222 		bpf_mtap_af(ifp, dst->sa_family, m);
223 	m->m_pkthdr.rcvif = ifp;
224 
225 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
226 		m_freem(m);
227 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
228 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
229 	}
230 
231 	ifp->if_opackets++;
232 	ifp->if_obytes += m->m_pkthdr.len;
233 
234 #ifdef ALTQ
235 	/*
236 	 * ALTQ on the loopback interface is just for debugging.  It's
237 	 * used only for loopback interfaces, not for a simplex interface.
238 	 */
239 	if ((ALTQ_IS_ENABLED(&ifp->if_snd) || TBR_IS_ENABLED(&ifp->if_snd)) &&
240 	    ifp->if_start == lostart) {
241 		struct altq_pktattr pktattr;
242 		int error;
243 
244 		/*
245 		 * If the queueing discipline needs packet classification,
246 		 * do it before prepending the link headers.
247 		 */
248 		IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family, &pktattr);
249 
250 		M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT);
251 		if (m == NULL)
252 			return (ENOBUFS);
253 		*(mtod(m, uint32_t *)) = dst->sa_family;
254 
255 		s = splnet();
256 		IFQ_ENQUEUE(&ifp->if_snd, m, &pktattr, error);
257 		(*ifp->if_start)(ifp);
258 		splx(s);
259 		return (error);
260 	}
261 #endif /* ALTQ */
262 
263 	m_tag_delete_nonpersistent(m);
264 
265 #ifdef MPLS
266 	if (rt != NULL && rt_gettag(rt) != NULL &&
267 	    rt_gettag(rt)->sa_family == AF_MPLS &&
268 	    (m->m_flags & (M_MCAST | M_BCAST)) == 0) {
269 		union mpls_shim msh;
270 		msh.s_addr = MPLS_GETSADDR(rt);
271 		if (msh.shim.label != MPLS_LABEL_IMPLNULL) {
272 			ifq = &mplsintrq;
273 			isr = NETISR_MPLS;
274 		}
275 	}
276 	if (isr != NETISR_MPLS)
277 #endif
278 	switch (dst->sa_family) {
279 
280 #ifdef INET
281 	case AF_INET:
282 		csum_flags = m->m_pkthdr.csum_flags;
283 		KASSERT((csum_flags & ~(M_CSUM_IPv4|M_CSUM_UDPv4)) == 0);
284 		if (csum_flags != 0 && IN_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
285 			ip_undefer_csum(m, 0, csum_flags);
286 		}
287 		m->m_pkthdr.csum_flags = 0;
288 		ifq = &ipintrq;
289 		isr = NETISR_IP;
290 		break;
291 #endif
292 #ifdef INET6
293 	case AF_INET6:
294 		csum_flags = m->m_pkthdr.csum_flags;
295 		KASSERT((csum_flags & ~M_CSUM_UDPv6) == 0);
296 		if (csum_flags != 0 &&
297 		    IN6_LOOPBACK_NEED_CHECKSUM(csum_flags)) {
298 			ip6_undefer_csum(m, 0, csum_flags);
299 		}
300 		m->m_pkthdr.csum_flags = 0;
301 		m->m_flags |= M_LOOP;
302 		ifq = &ip6intrq;
303 		isr = NETISR_IPV6;
304 		break;
305 #endif
306 #ifdef IPX
307 	case AF_IPX:
308 		ifq = &ipxintrq;
309 		isr = NETISR_IPX;
310 		break;
311 #endif
312 #ifdef NETATALK
313 	case AF_APPLETALK:
314 	        ifq = &atintrq2;
315 		isr = NETISR_ATALK;
316 		break;
317 #endif
318 	default:
319 		printf("%s: can't handle af%d\n", ifp->if_xname,
320 		    dst->sa_family);
321 		m_freem(m);
322 		return (EAFNOSUPPORT);
323 	}
324 	s = splnet();
325 	if (IF_QFULL(ifq)) {
326 		IF_DROP(ifq);
327 		m_freem(m);
328 		splx(s);
329 		return (ENOBUFS);
330 	}
331 	IF_ENQUEUE(ifq, m);
332 	schednetisr(isr);
333 	ifp->if_ipackets++;
334 	ifp->if_ibytes += m->m_pkthdr.len;
335 	splx(s);
336 	return (0);
337 }
338 
339 #ifdef ALTQ
340 static void
341 lostart(struct ifnet *ifp)
342 {
343 	struct ifqueue *ifq;
344 	struct mbuf *m;
345 	uint32_t af;
346 	int s, isr;
347 
348 	for (;;) {
349 		IFQ_DEQUEUE(&ifp->if_snd, m);
350 		if (m == NULL)
351 			return;
352 
353 		af = *(mtod(m, uint32_t *));
354 		m_adj(m, sizeof(uint32_t));
355 
356 		switch (af) {
357 #ifdef INET
358 		case AF_INET:
359 			ifq = &ipintrq;
360 			isr = NETISR_IP;
361 			break;
362 #endif
363 #ifdef INET6
364 		case AF_INET6:
365 			m->m_flags |= M_LOOP;
366 			ifq = &ip6intrq;
367 			isr = NETISR_IPV6;
368 			break;
369 #endif
370 #ifdef IPX
371 		case AF_IPX:
372 			ifq = &ipxintrq;
373 			isr = NETISR_IPX;
374 			break;
375 #endif
376 #ifdef NETATALK
377 		case AF_APPLETALK:
378 			ifq = &atintrq2;
379 			isr = NETISR_ATALK;
380 			break;
381 #endif
382 		default:
383 			printf("%s: can't handle af%d\n", ifp->if_xname, af);
384 			m_freem(m);
385 			return;
386 		}
387 
388 		s = splnet();
389 		if (IF_QFULL(ifq)) {
390 			IF_DROP(ifq);
391 			splx(s);
392 			m_freem(m);
393 			return;
394 		}
395 		IF_ENQUEUE(ifq, m);
396 		schednetisr(isr);
397 		ifp->if_ipackets++;
398 		ifp->if_ibytes += m->m_pkthdr.len;
399 		splx(s);
400 	}
401 }
402 #endif /* ALTQ */
403 
404 /* ARGSUSED */
405 void
406 lortrequest(int cmd, struct rtentry *rt,
407     const struct rt_addrinfo *info)
408 {
409 
410 	if (rt)
411 		rt->rt_rmx.rmx_mtu = lo0ifp->if_mtu;
412 }
413 
414 /*
415  * Process an ioctl request.
416  */
417 /* ARGSUSED */
418 int
419 loioctl(struct ifnet *ifp, u_long cmd, void *data)
420 {
421 	struct ifaddr *ifa;
422 	struct ifreq *ifr = data;
423 	int error = 0;
424 
425 	switch (cmd) {
426 
427 	case SIOCINITIFADDR:
428 		ifp->if_flags |= IFF_UP;
429 		ifa = (struct ifaddr *)data;
430 		if (ifa != NULL)
431 			ifa->ifa_rtrequest = lortrequest;
432 		/*
433 		 * Everything else is done at a higher level.
434 		 */
435 		break;
436 
437 	case SIOCSIFMTU:
438 		if ((unsigned)ifr->ifr_mtu > LOMTU_MAX)
439 			error = EINVAL;
440 		else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET){
441 			error = 0;
442 		}
443 		break;
444 
445 	case SIOCADDMULTI:
446 	case SIOCDELMULTI:
447 		if (ifr == NULL) {
448 			error = EAFNOSUPPORT;		/* XXX */
449 			break;
450 		}
451 		switch (ifreq_getaddr(cmd, ifr)->sa_family) {
452 
453 #ifdef INET
454 		case AF_INET:
455 			break;
456 #endif
457 #ifdef INET6
458 		case AF_INET6:
459 			break;
460 #endif
461 
462 		default:
463 			error = EAFNOSUPPORT;
464 			break;
465 		}
466 		break;
467 
468 	default:
469 		error = ifioctl_common(ifp, cmd, data);
470 	}
471 	return (error);
472 }
473