if_loop.c revision 113255 
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 113255 2003-04-08 14:25:47Z des $
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
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	 * KAME requires that the packet to be contiguous on the
205	 * mbuf.  We need to make that sure.
206	 * this kind of code should be avoided.
207	 * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
208	 */
209	if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
210		struct mbuf *n;
211
212		/* XXX MT_HEADER should be m->m_type */
213		MGETHDR(n, M_DONTWAIT, MT_HEADER);
214		if (!n)
215			goto contiguousfail;
216		M_MOVE_PKTHDR(n, m);
217#ifdef MAC
218		/*
219		 * XXXMAC: Once we put labels in tags and proper
220		 * primitives are used for relocating mbuf header
221		 * data, this will no longer be required.
222		 */
223		m->m_pkthdr.label.l_flags &= ~MAC_FLAG_INITIALIZED;
224#endif
225		MCLGET(n, M_DONTWAIT);
226		if (! (n->m_flags & M_EXT)) {
227			m_freem(n);
228			goto contiguousfail;
229		}
230
231		m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
232		n->m_len = n->m_pkthdr.len;
233		m_freem(m);
234		m = n;
235	}
236	if (0) {
237contiguousfail:
238		printf("looutput: mbuf allocation failed\n");
239	}
240
241	ifp->if_opackets++;
242	ifp->if_obytes += m->m_pkthdr.len;
243#if 1	/* XXX */
244	switch (dst->sa_family) {
245	case AF_INET:
246	case AF_INET6:
247	case AF_IPX:
248	case AF_APPLETALK:
249		break;
250	default:
251		printf("looutput: af=%d unexpected\n", dst->sa_family);
252		m_freem(m);
253		return (EAFNOSUPPORT);
254	}
255#endif
256	return(if_simloop(ifp, m, dst->sa_family, 0));
257}
258
259/*
260 * if_simloop()
261 *
262 * This function is to support software emulation of hardware loopback,
263 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
264 * hear their own broadcasts, we create a copy of the packet that we
265 * would normally receive via a hardware loopback.
266 *
267 * This function expects the packet to include the media header of length hlen.
268 */
269
270int
271if_simloop(ifp, m, af, hlen)
272	struct ifnet *ifp;
273	struct mbuf *m;
274	int af;
275	int hlen;
276{
277	int isr;
278
279	M_ASSERTPKTHDR(m);
280	m->m_pkthdr.rcvif = ifp;
281
282	/* BPF write needs to be handled specially */
283	if (af == AF_UNSPEC) {
284		KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
285		af = *(mtod(m, int *));
286		m->m_len -= sizeof(int);
287		m->m_pkthdr.len -= sizeof(int);
288		m->m_data += sizeof(int);
289	}
290
291	/* Let BPF see incoming packet */
292	if (ifp->if_bpf) {
293		struct mbuf m0, *n = m;
294
295		if (ifp->if_bpf->bif_dlt == DLT_NULL) {
296			/*
297			 * We need to prepend the address family as
298			 * a four byte field.  Cons up a dummy header
299			 * to pacify bpf.  This is safe because bpf
300			 * will only read from the mbuf (i.e., it won't
301			 * try to free it or keep a pointer a to it).
302			 */
303			m0.m_next = m;
304			m0.m_len = 4;
305			m0.m_data = (char *)&af;
306			n = &m0;
307		}
308		BPF_MTAP(ifp, n);
309	}
310
311	/* Strip away media header */
312	if (hlen > 0) {
313		m_adj(m, hlen);
314#if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
315		/* The alpha doesn't like unaligned data.
316		 * We move data down in the first mbuf */
317		if (mtod(m, vm_offset_t) & 3) {
318			KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
319			bcopy(m->m_data,
320			    (char *)(mtod(m, vm_offset_t)
321				- (mtod(m, vm_offset_t) & 3)),
322			    m->m_len);
323			mtod(m,vm_offset_t) -= (mtod(m, vm_offset_t) & 3);
324		}
325#endif
326	}
327
328	/* Deliver to upper layer protocol */
329	switch (af) {
330#ifdef INET
331	case AF_INET:
332		isr = NETISR_IP;
333		break;
334#endif
335#ifdef INET6
336	case AF_INET6:
337		m->m_flags |= M_LOOP;
338		isr = NETISR_IPV6;
339		break;
340#endif
341#ifdef IPX
342	case AF_IPX:
343		isr = NETISR_IPX;
344		break;
345#endif
346#ifdef NETATALK
347	case AF_APPLETALK:
348		isr = NETISR_ATALK2;
349		break;
350#endif
351	default:
352		printf("if_simloop: can't handle af=%d\n", af);
353		m_freem(m);
354		return (EAFNOSUPPORT);
355	}
356	ifp->if_ipackets++;
357	ifp->if_ibytes += m->m_pkthdr.len;
358	netisr_dispatch(isr, m);
359	return (0);
360}
361
362/* ARGSUSED */
363static void
364lortrequest(cmd, rt, info)
365	int cmd;
366	struct rtentry *rt;
367	struct rt_addrinfo *info;
368{
369	if (rt) {
370		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
371		/*
372		 * For optimal performance, the send and receive buffers
373		 * should be at least twice the MTU plus a little more for
374		 * overhead.
375		 */
376		rt->rt_rmx.rmx_recvpipe =
377			rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
378	}
379}
380
381/*
382 * Process an ioctl request.
383 */
384/* ARGSUSED */
385int
386loioctl(ifp, cmd, data)
387	register struct ifnet *ifp;
388	u_long cmd;
389	caddr_t data;
390{
391	register struct ifaddr *ifa;
392	register struct ifreq *ifr = (struct ifreq *)data;
393	register int error = 0;
394
395	switch (cmd) {
396
397	case SIOCSIFADDR:
398		ifp->if_flags |= IFF_UP | IFF_RUNNING;
399		ifa = (struct ifaddr *)data;
400		ifa->ifa_rtrequest = lortrequest;
401		/*
402		 * Everything else is done at a higher level.
403		 */
404		break;
405
406	case SIOCADDMULTI:
407	case SIOCDELMULTI:
408		if (ifr == 0) {
409			error = EAFNOSUPPORT;		/* XXX */
410			break;
411		}
412		switch (ifr->ifr_addr.sa_family) {
413
414#ifdef INET
415		case AF_INET:
416			break;
417#endif
418#ifdef INET6
419		case AF_INET6:
420			break;
421#endif
422
423		default:
424			error = EAFNOSUPPORT;
425			break;
426		}
427		break;
428
429	case SIOCSIFMTU:
430		ifp->if_mtu = ifr->ifr_mtu;
431		break;
432
433	case SIOCSIFFLAGS:
434		break;
435
436	default:
437		error = EINVAL;
438	}
439	return (error);
440}
441