if_loop.c revision 128209 
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: head/sys/net/if_loop.c 128209 2004-04-14 00:57:49Z brooks $
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#include "opt_mac.h"
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/kernel.h>
46#include <sys/mac.h>
47#include <sys/malloc.h>
48#include <sys/mbuf.h>
49#include <sys/module.h>
50#include <machine/bus.h>
51#include <sys/rman.h>
52#include <sys/socket.h>
53#include <sys/sockio.h>
54#include <sys/sysctl.h>
55
56#include <net/if.h>
57#include <net/if_types.h>
58#include <net/netisr.h>
59#include <net/route.h>
60#include <net/bpf.h>
61#include <net/bpfdesc.h>
62
63#ifdef	INET
64#include <netinet/in.h>
65#include <netinet/in_var.h>
66#endif
67
68#ifdef IPX
69#include <netipx/ipx.h>
70#include <netipx/ipx_if.h>
71#endif
72
73#ifdef INET6
74#ifndef INET
75#include <netinet/in.h>
76#endif
77#include <netinet6/in6_var.h>
78#include <netinet/ip6.h>
79#endif
80
81#ifdef NETATALK
82#include <netatalk/at.h>
83#include <netatalk/at_var.h>
84#endif
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 LONAME	"lo"
95
96struct lo_softc {
97	struct	ifnet sc_if;		/* network-visible interface */
98	LIST_ENTRY(lo_softc) sc_next;
99};
100
101int		loioctl(struct ifnet *, u_long, caddr_t);
102static void	lortrequest(int, struct rtentry *, struct rt_addrinfo *);
103int		looutput(struct ifnet *ifp, struct mbuf *m,
104		    struct sockaddr *dst, struct rtentry *rt);
105static int	lo_clone_create(struct if_clone *, int);
106static void	lo_clone_destroy(struct ifnet *);
107
108struct ifnet *loif = NULL;			/* Used externally */
109
110static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
111
112static struct mtx lo_mtx;
113static LIST_HEAD(lo_list, lo_softc) lo_list;
114
115struct if_clone lo_cloner = IF_CLONE_INITIALIZER(LONAME,
116    lo_clone_create, lo_clone_destroy, 1, IF_MAXUNIT);
117
118static void
119lo_clone_destroy(ifp)
120	struct ifnet *ifp;
121{
122	struct lo_softc *sc;
123
124	sc = ifp->if_softc;
125
126	/* XXX: destroying lo0 will lead to panics. */
127	KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
128
129	mtx_lock(&lo_mtx);
130	LIST_REMOVE(sc, sc_next);
131	mtx_unlock(&lo_mtx);
132	bpfdetach(ifp);
133	if_detach(ifp);
134	free(sc, M_LO);
135}
136
137static int
138lo_clone_create(ifc, unit)
139	struct if_clone *ifc;
140	int unit;
141{
142	struct lo_softc *sc;
143
144	MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
145
146	if_initname(&sc->sc_if, ifc->ifc_name, unit);
147	sc->sc_if.if_mtu = LOMTU;
148	sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
149	sc->sc_if.if_ioctl = loioctl;
150	sc->sc_if.if_output = looutput;
151	sc->sc_if.if_type = IFT_LOOP;
152	sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
153	sc->sc_if.if_softc = sc;
154	if_attach(&sc->sc_if);
155	bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
156	mtx_lock(&lo_mtx);
157	LIST_INSERT_HEAD(&lo_list, sc, sc_next);
158	mtx_unlock(&lo_mtx);
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		mtx_init(&lo_mtx, "lo_mtx", NULL, MTX_DEF);
171		LIST_INIT(&lo_list);
172		if_clone_attach(&lo_cloner);
173		break;
174	case MOD_UNLOAD:
175		printf("loop module unload - not possible for this module type\n");
176		return EINVAL;
177	}
178	return 0;
179}
180
181static moduledata_t loop_mod = {
182	"loop",
183	loop_modevent,
184	0
185};
186
187DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
188
189int
190looutput(ifp, m, dst, rt)
191	struct ifnet *ifp;
192	register struct mbuf *m;
193	struct sockaddr *dst;
194	register struct rtentry *rt;
195{
196	M_ASSERTPKTHDR(m); /* check if we have the packet header */
197
198	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
199		m_freem(m);
200		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
201		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
202	}
203
204	ifp->if_opackets++;
205	ifp->if_obytes += m->m_pkthdr.len;
206#if 1	/* XXX */
207	switch (dst->sa_family) {
208	case AF_INET:
209	case AF_INET6:
210	case AF_IPX:
211	case AF_APPLETALK:
212		break;
213	default:
214		printf("looutput: af=%d unexpected\n", dst->sa_family);
215		m_freem(m);
216		return (EAFNOSUPPORT);
217	}
218#endif
219	return(if_simloop(ifp, m, dst->sa_family, 0));
220}
221
222/*
223 * if_simloop()
224 *
225 * This function is to support software emulation of hardware loopback,
226 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
227 * hear their own broadcasts, we create a copy of the packet that we
228 * would normally receive via a hardware loopback.
229 *
230 * This function expects the packet to include the media header of length hlen.
231 */
232
233int
234if_simloop(ifp, m, af, hlen)
235	struct ifnet *ifp;
236	struct mbuf *m;
237	int af;
238	int hlen;
239{
240	int isr;
241
242	M_ASSERTPKTHDR(m);
243	m_tag_delete_nonpersistent(m);
244	m->m_pkthdr.rcvif = ifp;
245
246	/* BPF write needs to be handled specially */
247	if (af == AF_UNSPEC) {
248		KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
249		af = *(mtod(m, int *));
250		m->m_len -= sizeof(int);
251		m->m_pkthdr.len -= sizeof(int);
252		m->m_data += sizeof(int);
253	}
254
255	/* Let BPF see incoming packet */
256	if (ifp->if_bpf) {
257		if (ifp->if_bpf->bif_dlt == DLT_NULL) {
258			u_int32_t af1 = af;	/* XXX beware sizeof(af) != 4 */
259			/*
260			 * We need to prepend the address family.
261			 */
262			bpf_mtap2(ifp->if_bpf, &af1, sizeof(af1), m);
263		} else
264			bpf_mtap(ifp->if_bpf, m);
265	}
266
267	/* Strip away media header */
268	if (hlen > 0) {
269		m_adj(m, hlen);
270#if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
271		/* The alpha doesn't like unaligned data.
272		 * We move data down in the first mbuf */
273		if (mtod(m, vm_offset_t) & 3) {
274			KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
275			bcopy(m->m_data,
276			    (char *)(mtod(m, vm_offset_t)
277				- (mtod(m, vm_offset_t) & 3)),
278			    m->m_len);
279			mtod(m,vm_offset_t) -= (mtod(m, vm_offset_t) & 3);
280		}
281#endif
282	}
283
284	/* Deliver to upper layer protocol */
285	switch (af) {
286#ifdef INET
287	case AF_INET:
288		isr = NETISR_IP;
289		break;
290#endif
291#ifdef INET6
292	case AF_INET6:
293		m->m_flags |= M_LOOP;
294		isr = NETISR_IPV6;
295		break;
296#endif
297#ifdef IPX
298	case AF_IPX:
299		isr = NETISR_IPX;
300		break;
301#endif
302#ifdef NETATALK
303	case AF_APPLETALK:
304		isr = NETISR_ATALK2;
305		break;
306#endif
307	default:
308		printf("if_simloop: can't handle af=%d\n", af);
309		m_freem(m);
310		return (EAFNOSUPPORT);
311	}
312	ifp->if_ipackets++;
313	ifp->if_ibytes += m->m_pkthdr.len;
314	netisr_queue(isr, m);
315	return (0);
316}
317
318/* ARGSUSED */
319static void
320lortrequest(cmd, rt, info)
321	int cmd;
322	struct rtentry *rt;
323	struct rt_addrinfo *info;
324{
325	RT_LOCK_ASSERT(rt);
326	if (rt)
327		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
328}
329
330/*
331 * Process an ioctl request.
332 */
333/* ARGSUSED */
334int
335loioctl(ifp, cmd, data)
336	register struct ifnet *ifp;
337	u_long cmd;
338	caddr_t data;
339{
340	register struct ifaddr *ifa;
341	register struct ifreq *ifr = (struct ifreq *)data;
342	register int error = 0;
343
344	switch (cmd) {
345
346	case SIOCSIFADDR:
347		ifp->if_flags |= IFF_UP | IFF_RUNNING;
348		ifa = (struct ifaddr *)data;
349		ifa->ifa_rtrequest = lortrequest;
350		/*
351		 * Everything else is done at a higher level.
352		 */
353		break;
354
355	case SIOCADDMULTI:
356	case SIOCDELMULTI:
357		if (ifr == 0) {
358			error = EAFNOSUPPORT;		/* XXX */
359			break;
360		}
361		switch (ifr->ifr_addr.sa_family) {
362
363#ifdef INET
364		case AF_INET:
365			break;
366#endif
367#ifdef INET6
368		case AF_INET6:
369			break;
370#endif
371
372		default:
373			error = EAFNOSUPPORT;
374			break;
375		}
376		break;
377
378	case SIOCSIFMTU:
379		ifp->if_mtu = ifr->ifr_mtu;
380		break;
381
382	case SIOCSIFFLAGS:
383		break;
384
385	default:
386		error = EINVAL;
387	}
388	return (error);
389}
390