if_loop.c revision 147611 
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 147611 2005-06-26 18:11:11Z dwmalone $
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
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/malloc.h>
46#include <sys/mbuf.h>
47#include <sys/module.h>
48#include <machine/bus.h>
49#include <sys/rman.h>
50#include <sys/socket.h>
51#include <sys/sockio.h>
52#include <sys/sysctl.h>
53
54#include <net/if.h>
55#include <net/if_clone.h>
56#include <net/if_types.h>
57#include <net/netisr.h>
58#include <net/route.h>
59#include <net/bpf.h>
60#include <net/bpfdesc.h>
61
62#ifdef	INET
63#include <netinet/in.h>
64#include <netinet/in_var.h>
65#endif
66
67#ifdef IPX
68#include <netipx/ipx.h>
69#include <netipx/ipx_if.h>
70#endif
71
72#ifdef INET6
73#ifndef INET
74#include <netinet/in.h>
75#endif
76#include <netinet6/in6_var.h>
77#include <netinet/ip6.h>
78#endif
79
80#ifdef NETATALK
81#include <netatalk/at.h>
82#include <netatalk/at_var.h>
83#endif
84
85#ifdef TINY_LOMTU
86#define	LOMTU	(1024+512)
87#elif defined(LARGE_LOMTU)
88#define LOMTU	131072
89#else
90#define LOMTU	16384
91#endif
92
93#define LONAME	"lo"
94
95struct lo_softc {
96	struct	ifnet *sc_ifp;
97	LIST_ENTRY(lo_softc) sc_next;
98};
99
100int		loioctl(struct ifnet *, u_long, caddr_t);
101static void	lortrequest(int, struct rtentry *, struct rt_addrinfo *);
102int		looutput(struct ifnet *ifp, struct mbuf *m,
103		    struct sockaddr *dst, struct rtentry *rt);
104static int	lo_clone_create(struct if_clone *, int);
105static void	lo_clone_destroy(struct ifnet *);
106
107struct ifnet *loif = NULL;			/* Used externally */
108
109static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
110
111static struct mtx lo_mtx;
112static LIST_HEAD(lo_list, lo_softc) lo_list;
113
114IFC_SIMPLE_DECLARE(lo, 1);
115
116static void
117lo_clone_destroy(ifp)
118	struct ifnet *ifp;
119{
120	struct lo_softc *sc;
121
122	sc = ifp->if_softc;
123
124	/* XXX: destroying lo0 will lead to panics. */
125	KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
126
127	mtx_lock(&lo_mtx);
128	LIST_REMOVE(sc, sc_next);
129	mtx_unlock(&lo_mtx);
130	bpfdetach(ifp);
131	if_detach(ifp);
132	if_free(ifp);
133	free(sc, M_LO);
134}
135
136static int
137lo_clone_create(ifc, unit)
138	struct if_clone *ifc;
139	int unit;
140{
141	struct ifnet *ifp;
142	struct lo_softc *sc;
143
144	MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
145	ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
146	if (ifp == NULL) {
147		free(sc, M_LO);
148		return (ENOSPC);
149	}
150
151	if_initname(ifp, ifc->ifc_name, unit);
152	ifp->if_mtu = LOMTU;
153	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
154	ifp->if_ioctl = loioctl;
155	ifp->if_output = looutput;
156	ifp->if_snd.ifq_maxlen = ifqmaxlen;
157	ifp->if_softc = sc;
158	if_attach(ifp);
159	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
160	mtx_lock(&lo_mtx);
161	LIST_INSERT_HEAD(&lo_list, sc, sc_next);
162	mtx_unlock(&lo_mtx);
163	if (loif == NULL)
164		loif = ifp;
165
166	return (0);
167}
168
169static int
170loop_modevent(module_t mod, int type, void *data)
171{
172	switch (type) {
173	case MOD_LOAD:
174		mtx_init(&lo_mtx, "lo_mtx", NULL, MTX_DEF);
175		LIST_INIT(&lo_list);
176		if_clone_attach(&lo_cloner);
177		break;
178	case MOD_UNLOAD:
179		printf("loop module unload - not possible for this module type\n");
180		return EINVAL;
181	default:
182		return EOPNOTSUPP;
183	}
184	return 0;
185}
186
187static moduledata_t loop_mod = {
188	"loop",
189	loop_modevent,
190	0
191};
192
193DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
194
195int
196looutput(ifp, m, dst, rt)
197	struct ifnet *ifp;
198	register struct mbuf *m;
199	struct sockaddr *dst;
200	register struct rtentry *rt;
201{
202	u_int32_t af;
203
204	M_ASSERTPKTHDR(m); /* check if we have the packet header */
205
206	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
207		m_freem(m);
208		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
209		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
210	}
211
212	ifp->if_opackets++;
213	ifp->if_obytes += m->m_pkthdr.len;
214
215	/* BPF writes need to be handled specially. */
216	if (dst->sa_family == AF_UNSPEC) {
217		bcopy(dst->sa_data, &af, sizeof(af));
218		dst->sa_family = af;
219	}
220
221#if 1	/* XXX */
222	switch (dst->sa_family) {
223	case AF_INET:
224	case AF_INET6:
225	case AF_IPX:
226	case AF_APPLETALK:
227		break;
228	default:
229		printf("looutput: af=%d unexpected\n", dst->sa_family);
230		m_freem(m);
231		return (EAFNOSUPPORT);
232	}
233#endif
234	return(if_simloop(ifp, m, dst->sa_family, 0));
235}
236
237/*
238 * if_simloop()
239 *
240 * This function is to support software emulation of hardware loopback,
241 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
242 * hear their own broadcasts, we create a copy of the packet that we
243 * would normally receive via a hardware loopback.
244 *
245 * This function expects the packet to include the media header of length hlen.
246 */
247
248int
249if_simloop(ifp, m, af, hlen)
250	struct ifnet *ifp;
251	struct mbuf *m;
252	int af;
253	int hlen;
254{
255	int isr;
256
257	M_ASSERTPKTHDR(m);
258	m_tag_delete_nonpersistent(m);
259	m->m_pkthdr.rcvif = ifp;
260
261	/* Let BPF see incoming packet */
262	if (ifp->if_bpf) {
263		if (ifp->if_bpf->bif_dlt == DLT_NULL) {
264			u_int32_t af1 = af;	/* XXX beware sizeof(af) != 4 */
265			/*
266			 * We need to prepend the address family.
267			 */
268			bpf_mtap2(ifp->if_bpf, &af1, sizeof(af1), m);
269		} else
270			bpf_mtap(ifp->if_bpf, m);
271	}
272
273	/* Strip away media header */
274	if (hlen > 0) {
275		m_adj(m, hlen);
276#if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
277		/* The alpha doesn't like unaligned data.
278		 * We move data down in the first mbuf */
279		if (mtod(m, vm_offset_t) & 3) {
280			KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
281			bcopy(m->m_data,
282			    (char *)(mtod(m, vm_offset_t)
283				- (mtod(m, vm_offset_t) & 3)),
284			    m->m_len);
285			m->m_data -= (mtod(m,vm_offset_t) & 3);
286		}
287#endif
288	}
289
290	/* Deliver to upper layer protocol */
291	switch (af) {
292#ifdef INET
293	case AF_INET:
294		isr = NETISR_IP;
295		break;
296#endif
297#ifdef INET6
298	case AF_INET6:
299		m->m_flags |= M_LOOP;
300		isr = NETISR_IPV6;
301		break;
302#endif
303#ifdef IPX
304	case AF_IPX:
305		isr = NETISR_IPX;
306		break;
307#endif
308#ifdef NETATALK
309	case AF_APPLETALK:
310		isr = NETISR_ATALK2;
311		break;
312#endif
313	default:
314		printf("if_simloop: can't handle af=%d\n", af);
315		m_freem(m);
316		return (EAFNOSUPPORT);
317	}
318	ifp->if_ipackets++;
319	ifp->if_ibytes += m->m_pkthdr.len;
320	netisr_queue(isr, m);	/* mbuf is free'd on failure. */
321	return (0);
322}
323
324/* ARGSUSED */
325static void
326lortrequest(cmd, rt, info)
327	int cmd;
328	struct rtentry *rt;
329	struct rt_addrinfo *info;
330{
331	RT_LOCK_ASSERT(rt);
332	rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
333}
334
335/*
336 * Process an ioctl request.
337 */
338/* ARGSUSED */
339int
340loioctl(ifp, cmd, data)
341	register struct ifnet *ifp;
342	u_long cmd;
343	caddr_t data;
344{
345	register struct ifaddr *ifa;
346	register struct ifreq *ifr = (struct ifreq *)data;
347	register int error = 0;
348
349	switch (cmd) {
350
351	case SIOCSIFADDR:
352		ifp->if_flags |= IFF_UP | IFF_RUNNING;
353		ifa = (struct ifaddr *)data;
354		ifa->ifa_rtrequest = lortrequest;
355		/*
356		 * Everything else is done at a higher level.
357		 */
358		break;
359
360	case SIOCADDMULTI:
361	case SIOCDELMULTI:
362		if (ifr == 0) {
363			error = EAFNOSUPPORT;		/* XXX */
364			break;
365		}
366		switch (ifr->ifr_addr.sa_family) {
367
368#ifdef INET
369		case AF_INET:
370			break;
371#endif
372#ifdef INET6
373		case AF_INET6:
374			break;
375#endif
376
377		default:
378			error = EAFNOSUPPORT;
379			break;
380		}
381		break;
382
383	case SIOCSIFMTU:
384		ifp->if_mtu = ifr->ifr_mtu;
385		break;
386
387	case SIOCSIFFLAGS:
388		break;
389
390	default:
391		error = EINVAL;
392	}
393	return (error);
394}
395