if_loop.c revision 118688 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	@(#)if_loop.c	8.2 (Berkeley) 1/9/95
34 * $FreeBSD: head/sys/net/if_loop.c 118688 2003-08-09 05:44:00Z silby $
35 */
36
37/*
38 * Loopback interface driver for protocol testing and timing.
39 */
40
41#include "opt_atalk.h"
42#include "opt_inet.h"
43#include "opt_inet6.h"
44#include "opt_ipx.h"
45#include "opt_mac.h"
46
47#include <sys/param.h>
48#include <sys/systm.h>
49#include <sys/kernel.h>
50#include <sys/mac.h>
51#include <sys/malloc.h>
52#include <sys/mbuf.h>
53#include <sys/module.h>
54#include <machine/bus.h>
55#include <sys/rman.h>
56#include <sys/socket.h>
57#include <sys/sockio.h>
58#include <sys/sysctl.h>
59
60#include <net/if.h>
61#include <net/if_types.h>
62#include <net/netisr.h>
63#include <net/route.h>
64#include <net/bpf.h>
65#include <net/bpfdesc.h>
66
67#ifdef	INET
68#include <netinet/in.h>
69#include <netinet/in_var.h>
70#endif
71
72#ifdef IPX
73#include <netipx/ipx.h>
74#include <netipx/ipx_if.h>
75#endif
76
77#ifdef INET6
78#ifndef INET
79#include <netinet/in.h>
80#endif
81#include <netinet6/in6_var.h>
82#include <netinet/ip6.h>
83#endif
84
85#ifdef NETATALK
86#include <netatalk/at.h>
87#include <netatalk/at_var.h>
88#endif
89
90#ifdef TINY_LOMTU
91#define	LOMTU	(1024+512)
92#elif defined(LARGE_LOMTU)
93#define LOMTU	131072
94#else
95#define LOMTU	16384
96#endif
97
98#define LONAME	"lo"
99
100struct lo_softc {
101	struct	ifnet sc_if;		/* network-visible interface */
102	LIST_ENTRY(lo_softc) sc_next;
103};
104
105int		loioctl(struct ifnet *, u_long, caddr_t);
106static void	lortrequest(int, struct rtentry *, struct rt_addrinfo *);
107int		looutput(struct ifnet *ifp, struct mbuf *m,
108		    struct sockaddr *dst, struct rtentry *rt);
109int		lo_clone_create(struct if_clone *, int);
110void		lo_clone_destroy(struct ifnet *);
111
112struct ifnet *loif = NULL;			/* Used externally */
113
114static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
115
116static LIST_HEAD(lo_list, lo_softc) lo_list;
117
118struct if_clone lo_cloner = IF_CLONE_INITIALIZER(LONAME,
119    lo_clone_create, lo_clone_destroy, 1, IF_MAXUNIT);
120
121void
122lo_clone_destroy(ifp)
123	struct ifnet *ifp;
124{
125	struct lo_softc *sc;
126
127	sc = ifp->if_softc;
128
129	/* XXX: destroying lo0 will lead to panics. */
130	KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
131
132	bpfdetach(ifp);
133	if_detach(ifp);
134	LIST_REMOVE(sc, sc_next);
135	free(sc, M_LO);
136}
137
138int
139lo_clone_create(ifc, unit)
140	struct if_clone *ifc;
141	int unit;
142{
143	struct lo_softc *sc;
144
145	MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
146
147	sc->sc_if.if_name = LONAME;
148	sc->sc_if.if_unit = unit;
149	sc->sc_if.if_mtu = LOMTU;
150	sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
151	sc->sc_if.if_ioctl = loioctl;
152	sc->sc_if.if_output = looutput;
153	sc->sc_if.if_type = IFT_LOOP;
154	sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
155	sc->sc_if.if_softc = sc;
156	if_attach(&sc->sc_if);
157	bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
158	LIST_INSERT_HEAD(&lo_list, sc, sc_next);
159	if (loif == NULL)
160		loif = &sc->sc_if;
161
162	return (0);
163}
164
165static int
166loop_modevent(module_t mod, int type, void *data)
167{
168	switch (type) {
169	case MOD_LOAD:
170		LIST_INIT(&lo_list);
171		if_clone_attach(&lo_cloner);
172		break;
173	case MOD_UNLOAD:
174		printf("loop module unload - not possible for this module type\n");
175		return EINVAL;
176	}
177	return 0;
178}
179
180static moduledata_t loop_mod = {
181	"loop",
182	loop_modevent,
183	0
184};
185
186DECLARE_MODULE(loop, loop_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
187
188int
189looutput(ifp, m, dst, rt)
190	struct ifnet *ifp;
191	register struct mbuf *m;
192	struct sockaddr *dst;
193	register struct rtentry *rt;
194{
195#ifdef INET6
196	struct mbuf *n;
197#endif
198
199	M_ASSERTPKTHDR(m); /* check if we have the packet header */
200
201	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
202		m_freem(m);
203		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
204		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
205	}
206#ifdef INET6
207	/*
208	 * KAME requires that the packet to be contiguous on the
209	 * mbuf.  We need to make that sure.
210	 * this kind of code should be avoided.
211	 *
212	 * XXX: KAME may no longer need contiguous packets.  Once
213	 * that has been verified, the following code _should_ be
214	 * removed.
215	 */
216
217	if (m && m->m_next != NULL) {
218
219		n = m_defrag(m, M_DONTWAIT);
220
221		if (n == NULL) {
222			m_freem(m);
223			return (ENOBUFS);
224		} else {
225			m = n;
226		}
227	}
228#endif
229
230	ifp->if_opackets++;
231	ifp->if_obytes += m->m_pkthdr.len;
232#if 1	/* XXX */
233	switch (dst->sa_family) {
234	case AF_INET:
235	case AF_INET6:
236	case AF_IPX:
237	case AF_APPLETALK:
238		break;
239	default:
240		printf("looutput: af=%d unexpected\n", dst->sa_family);
241		m_freem(m);
242		return (EAFNOSUPPORT);
243	}
244#endif
245	return(if_simloop(ifp, m, dst->sa_family, 0));
246}
247
248/*
249 * if_simloop()
250 *
251 * This function is to support software emulation of hardware loopback,
252 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
253 * hear their own broadcasts, we create a copy of the packet that we
254 * would normally receive via a hardware loopback.
255 *
256 * This function expects the packet to include the media header of length hlen.
257 */
258
259int
260if_simloop(ifp, m, af, hlen)
261	struct ifnet *ifp;
262	struct mbuf *m;
263	int af;
264	int hlen;
265{
266	int isr;
267
268	M_ASSERTPKTHDR(m);
269	m->m_pkthdr.rcvif = ifp;
270
271	/* BPF write needs to be handled specially */
272	if (af == AF_UNSPEC) {
273		KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
274		af = *(mtod(m, int *));
275		m->m_len -= sizeof(int);
276		m->m_pkthdr.len -= sizeof(int);
277		m->m_data += sizeof(int);
278	}
279
280	/* Let BPF see incoming packet */
281	if (ifp->if_bpf) {
282		struct mbuf m0, *n = m;
283
284		if (ifp->if_bpf->bif_dlt == DLT_NULL) {
285			/*
286			 * We need to prepend the address family as
287			 * a four byte field.  Cons up a dummy header
288			 * to pacify bpf.  This is safe because bpf
289			 * will only read from the mbuf (i.e., it won't
290			 * try to free it or keep a pointer a to it).
291			 */
292			m0.m_next = m;
293			m0.m_len = 4;
294			m0.m_data = (char *)&af;
295			n = &m0;
296		}
297		BPF_MTAP(ifp, n);
298	}
299
300	/* Strip away media header */
301	if (hlen > 0) {
302		m_adj(m, hlen);
303#if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
304		/* The alpha doesn't like unaligned data.
305		 * We move data down in the first mbuf */
306		if (mtod(m, vm_offset_t) & 3) {
307			KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
308			bcopy(m->m_data,
309			    (char *)(mtod(m, vm_offset_t)
310				- (mtod(m, vm_offset_t) & 3)),
311			    m->m_len);
312			mtod(m,vm_offset_t) -= (mtod(m, vm_offset_t) & 3);
313		}
314#endif
315	}
316
317	/* Deliver to upper layer protocol */
318	switch (af) {
319#ifdef INET
320	case AF_INET:
321		isr = NETISR_IP;
322		break;
323#endif
324#ifdef INET6
325	case AF_INET6:
326		m->m_flags |= M_LOOP;
327		isr = NETISR_IPV6;
328		break;
329#endif
330#ifdef IPX
331	case AF_IPX:
332		isr = NETISR_IPX;
333		break;
334#endif
335#ifdef NETATALK
336	case AF_APPLETALK:
337		isr = NETISR_ATALK2;
338		break;
339#endif
340	default:
341		printf("if_simloop: can't handle af=%d\n", af);
342		m_freem(m);
343		return (EAFNOSUPPORT);
344	}
345	ifp->if_ipackets++;
346	ifp->if_ibytes += m->m_pkthdr.len;
347	netisr_dispatch(isr, m);
348	return (0);
349}
350
351/* ARGSUSED */
352static void
353lortrequest(cmd, rt, info)
354	int cmd;
355	struct rtentry *rt;
356	struct rt_addrinfo *info;
357{
358	if (rt) {
359		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
360		/*
361		 * For optimal performance, the send and receive buffers
362		 * should be at least twice the MTU plus a little more for
363		 * overhead.
364		 */
365		rt->rt_rmx.rmx_recvpipe =
366			rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
367	}
368}
369
370/*
371 * Process an ioctl request.
372 */
373/* ARGSUSED */
374int
375loioctl(ifp, cmd, data)
376	register struct ifnet *ifp;
377	u_long cmd;
378	caddr_t data;
379{
380	register struct ifaddr *ifa;
381	register struct ifreq *ifr = (struct ifreq *)data;
382	register int error = 0;
383
384	switch (cmd) {
385
386	case SIOCSIFADDR:
387		ifp->if_flags |= IFF_UP | IFF_RUNNING;
388		ifa = (struct ifaddr *)data;
389		ifa->ifa_rtrequest = lortrequest;
390		/*
391		 * Everything else is done at a higher level.
392		 */
393		break;
394
395	case SIOCADDMULTI:
396	case SIOCDELMULTI:
397		if (ifr == 0) {
398			error = EAFNOSUPPORT;		/* XXX */
399			break;
400		}
401		switch (ifr->ifr_addr.sa_family) {
402
403#ifdef INET
404		case AF_INET:
405			break;
406#endif
407#ifdef INET6
408		case AF_INET6:
409			break;
410#endif
411
412		default:
413			error = EAFNOSUPPORT;
414			break;
415		}
416		break;
417
418	case SIOCSIFMTU:
419		ifp->if_mtu = ifr->ifr_mtu;
420		break;
421
422	case SIOCSIFFLAGS:
423		break;
424
425	default:
426		error = EINVAL;
427	}
428	return (error);
429}
430