if_loop.c revision 189873 
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 189873 2009-03-16 10:56:50Z rwatson $
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_route.h"
42#include "opt_mac.h"
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/kernel.h>
47#include <sys/mbuf.h>
48#include <sys/module.h>
49#include <machine/bus.h>
50#include <sys/rman.h>
51#include <sys/socket.h>
52#include <sys/sockio.h>
53#include <sys/sysctl.h>
54#include <sys/vimage.h>
55
56#include <net/if.h>
57#include <net/if_clone.h>
58#include <net/if_types.h>
59#include <net/netisr.h>
60#include <net/route.h>
61#include <net/bpf.h>
62#include <net/vnet.h>
63
64#ifdef	INET
65#include <netinet/in.h>
66#include <netinet/in_var.h>
67#endif
68
69#ifdef IPX
70#include <netipx/ipx.h>
71#include <netipx/ipx_if.h>
72#endif
73
74#ifdef INET6
75#ifndef INET
76#include <netinet/in.h>
77#endif
78#include <netinet6/in6_var.h>
79#include <netinet/ip6.h>
80#endif
81
82#ifdef NETATALK
83#include <netatalk/at.h>
84#include <netatalk/at_var.h>
85#endif
86
87#include <security/mac/mac_framework.h>
88
89#ifdef TINY_LOMTU
90#define	LOMTU	(1024+512)
91#elif defined(LARGE_LOMTU)
92#define LOMTU	131072
93#else
94#define LOMTU	16384
95#endif
96
97#define	LO_CSUM_FEATURES	(CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
98#define	LO_CSUM_SET		(CSUM_DATA_VALID | CSUM_PSEUDO_HDR | \
99				    CSUM_IP_CHECKED | CSUM_IP_VALID | \
100				    CSUM_SCTP_VALID)
101
102int		loioctl(struct ifnet *, u_long, caddr_t);
103static void	lortrequest(int, struct rtentry *, struct rt_addrinfo *);
104int		looutput(struct ifnet *ifp, struct mbuf *m,
105		    struct sockaddr *dst, struct rtentry *rt);
106static int	lo_clone_create(struct if_clone *, int, caddr_t);
107static void	lo_clone_destroy(struct ifnet *);
108
109#ifdef VIMAGE_GLOBALS
110struct ifnet *loif;			/* Used externally */
111#endif
112
113IFC_SIMPLE_DECLARE(lo, 1);
114
115static void
116lo_clone_destroy(struct ifnet *ifp)
117{
118#ifdef INVARIANTS
119	INIT_VNET_NET(ifp->if_vnet);
120#endif
121
122	/* XXX: destroying lo0 will lead to panics. */
123	KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
124
125	bpfdetach(ifp);
126	if_detach(ifp);
127	if_free(ifp);
128}
129
130static int
131lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
132{
133	INIT_VNET_NET(curvnet);
134	struct ifnet *ifp;
135
136	ifp = if_alloc(IFT_LOOP);
137	if (ifp == NULL)
138		return (ENOSPC);
139
140	if_initname(ifp, ifc->ifc_name, unit);
141	ifp->if_mtu = LOMTU;
142	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
143	ifp->if_ioctl = loioctl;
144	ifp->if_output = looutput;
145	ifp->if_snd.ifq_maxlen = ifqmaxlen;
146	ifp->if_capabilities = ifp->if_capenable = IFCAP_HWCSUM;
147	ifp->if_hwassist = LO_CSUM_FEATURES;
148	if_attach(ifp);
149	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
150	if (V_loif == NULL)
151		V_loif = ifp;
152
153	return (0);
154}
155
156static int
157loop_modevent(module_t mod, int type, void *data)
158{
159	INIT_VNET_NET(curvnet);
160
161	switch (type) {
162	case MOD_LOAD:
163		V_loif = NULL;
164		if_clone_attach(&lo_cloner);
165		break;
166
167	case MOD_UNLOAD:
168		printf("loop module unload - not possible for this module type\n");
169		return (EINVAL);
170
171	default:
172		return (EOPNOTSUPP);
173	}
174	return (0);
175}
176
177static moduledata_t loop_mod = {
178	"loop",
179	loop_modevent,
180	0
181};
182
183DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
184
185int
186looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
187    struct rtentry *rt)
188{
189	u_int32_t af;
190#ifdef MAC
191	int error;
192#endif
193
194	M_ASSERTPKTHDR(m); /* check if we have the packet header */
195
196#ifdef MAC
197	error = mac_ifnet_check_transmit(ifp, m);
198	if (error) {
199		m_freem(m);
200		return (error);
201	}
202#endif
203
204	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
205		m_freem(m);
206		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
207		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
208	}
209
210	ifp->if_opackets++;
211	ifp->if_obytes += m->m_pkthdr.len;
212
213	/* BPF writes need to be handled specially. */
214	if (dst->sa_family == AF_UNSPEC) {
215		bcopy(dst->sa_data, &af, sizeof(af));
216		dst->sa_family = af;
217	}
218
219#if 1	/* XXX */
220	switch (dst->sa_family) {
221	case AF_INET:
222		if (ifp->if_capenable & IFCAP_RXCSUM) {
223			m->m_pkthdr.csum_data = 0xffff;
224			m->m_pkthdr.csum_flags = LO_CSUM_SET;
225		}
226		m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
227	case AF_INET6:
228	case AF_IPX:
229	case AF_APPLETALK:
230		break;
231	default:
232		printf("looutput: af=%d unexpected\n", dst->sa_family);
233		m_freem(m);
234		return (EAFNOSUPPORT);
235	}
236#endif
237	return (if_simloop(ifp, m, dst->sa_family, 0));
238}
239
240/*
241 * if_simloop()
242 *
243 * This function is to support software emulation of hardware loopback,
244 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
245 * hear their own broadcasts, we create a copy of the packet that we
246 * would normally receive via a hardware loopback.
247 *
248 * This function expects the packet to include the media header of length hlen.
249 */
250int
251if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
252{
253	INIT_VNET_NET(ifp->if_vnet);
254	int isr;
255
256	M_ASSERTPKTHDR(m);
257	m_tag_delete_nonpersistent(m);
258	m->m_pkthdr.rcvif = ifp;
259
260#ifdef MAC
261	mac_ifnet_create_mbuf(ifp, m);
262#endif
263
264	/*
265	 * Let BPF see incoming packet in the following manner:
266	 *  - Emulated packet loopback for a simplex interface
267	 *    (net/if_ethersubr.c)
268	 *	-> passes it to ifp's BPF
269	 *  - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
270	 *	-> not passes it to any BPF
271	 *  - Normal packet loopback from myself to myself (net/if_loop.c)
272	 *	-> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
273	 */
274	if (hlen > 0) {
275		if (bpf_peers_present(ifp->if_bpf)) {
276			bpf_mtap(ifp->if_bpf, m);
277		}
278	} else {
279		if (bpf_peers_present(V_loif->if_bpf)) {
280			if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
281				/* XXX beware sizeof(af) != 4 */
282				u_int32_t af1 = af;
283
284				/*
285				 * We need to prepend the address family.
286				 */
287				bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
288			}
289		}
290	}
291
292	/* Strip away media header */
293	if (hlen > 0) {
294		m_adj(m, hlen);
295#ifndef __NO_STRICT_ALIGNMENT
296		/*
297		 * Some archs do not like unaligned data, so
298		 * we move data down in the first mbuf.
299		 */
300		if (mtod(m, vm_offset_t) & 3) {
301			KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
302			bcopy(m->m_data,
303			    (char *)(mtod(m, vm_offset_t)
304				- (mtod(m, vm_offset_t) & 3)),
305			    m->m_len);
306			m->m_data -= (mtod(m,vm_offset_t) & 3);
307		}
308#endif
309	}
310
311	/* Deliver to upper layer protocol */
312	switch (af) {
313#ifdef INET
314	case AF_INET:
315		isr = NETISR_IP;
316		break;
317#endif
318#ifdef INET6
319	case AF_INET6:
320		m->m_flags |= M_LOOP;
321		isr = NETISR_IPV6;
322		break;
323#endif
324#ifdef IPX
325	case AF_IPX:
326		isr = NETISR_IPX;
327		break;
328#endif
329#ifdef NETATALK
330	case AF_APPLETALK:
331		isr = NETISR_ATALK2;
332		break;
333#endif
334	default:
335		printf("if_simloop: can't handle af=%d\n", af);
336		m_freem(m);
337		return (EAFNOSUPPORT);
338	}
339	ifp->if_ipackets++;
340	ifp->if_ibytes += m->m_pkthdr.len;
341	netisr_queue(isr, m);	/* mbuf is free'd on failure. */
342	return (0);
343}
344
345/* ARGSUSED */
346static void
347lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
348{
349
350	RT_LOCK_ASSERT(rt);
351	rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
352}
353
354/*
355 * Process an ioctl request.
356 */
357/* ARGSUSED */
358int
359loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
360{
361	struct ifaddr *ifa;
362	struct ifreq *ifr = (struct ifreq *)data;
363	int error = 0, mask;
364
365	switch (cmd) {
366	case SIOCSIFADDR:
367		ifp->if_flags |= IFF_UP;
368		ifp->if_drv_flags |= IFF_DRV_RUNNING;
369		ifa = (struct ifaddr *)data;
370		ifa->ifa_rtrequest = lortrequest;
371		/*
372		 * Everything else is done at a higher level.
373		 */
374		break;
375
376	case SIOCADDMULTI:
377	case SIOCDELMULTI:
378		if (ifr == 0) {
379			error = EAFNOSUPPORT;		/* XXX */
380			break;
381		}
382		switch (ifr->ifr_addr.sa_family) {
383
384#ifdef INET
385		case AF_INET:
386			break;
387#endif
388#ifdef INET6
389		case AF_INET6:
390			break;
391#endif
392
393		default:
394			error = EAFNOSUPPORT;
395			break;
396		}
397		break;
398
399	case SIOCSIFMTU:
400		ifp->if_mtu = ifr->ifr_mtu;
401		break;
402
403	case SIOCSIFFLAGS:
404		break;
405
406	case SIOCSIFCAP:
407		mask = ifp->if_capenable ^ ifr->ifr_reqcap;
408		if ((mask & IFCAP_RXCSUM) != 0)
409			ifp->if_capenable ^= IFCAP_RXCSUM;
410		if ((mask & IFCAP_TXCSUM) != 0)
411			ifp->if_capenable ^= IFCAP_TXCSUM;
412		if (ifp->if_capenable & IFCAP_TXCSUM)
413			ifp->if_hwassist = LO_CSUM_FEATURES;
414		else
415			ifp->if_hwassist = 0;
416		break;
417
418	default:
419		error = EINVAL;
420	}
421	return (error);
422}
423