if_disc.c revision 131669 
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 *	From: @(#)if_loop.c	8.1 (Berkeley) 6/10/93
30 * $FreeBSD: head/sys/net/if_disc.c 131669 2004-07-06 03:07:50Z bms $
31 */
32
33/*
34 * Discard interface driver for protocol testing and timing.
35 * (Based on the loopback.)
36 */
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/malloc.h>
42#include <sys/module.h>
43#include <sys/mbuf.h>
44#include <sys/socket.h>
45#include <sys/sockio.h>
46
47#include <net/if.h>
48#include <net/if_clone.h>
49#include <net/if_types.h>
50#include <net/route.h>
51#include <net/bpf.h>
52
53#include "opt_inet.h"
54#include "opt_inet6.h"
55
56#ifdef TINY_DSMTU
57#define	DSMTU	(1024+512)
58#else
59#define DSMTU	65532
60#endif
61
62#define DISCNAME	"disc"
63
64struct disc_softc {
65	struct ifnet sc_if;	/* must be first */
66	LIST_ENTRY(disc_softc) sc_list;
67};
68
69static int	discoutput(struct ifnet *, struct mbuf *,
70		    struct sockaddr *, struct rtentry *);
71static void	discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
72static int	discioctl(struct ifnet *, u_long, caddr_t);
73static int	disc_clone_create(struct if_clone *, int);
74static void	disc_clone_destroy(struct ifnet *);
75
76static struct mtx disc_mtx;
77static MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
78static LIST_HEAD(, disc_softc) disc_softc_list;
79
80IFC_SIMPLE_DECLARE(disc, 0);
81
82static int
83disc_clone_create(struct if_clone *ifc, int unit)
84{
85	struct ifnet		*ifp;
86	struct disc_softc	*sc;
87
88	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK);
89	bzero(sc, sizeof(struct disc_softc));
90
91	ifp = &sc->sc_if;
92
93	ifp->if_softc = sc;
94	if_initname(ifp, ifc->ifc_name, unit);
95	ifp->if_mtu = DSMTU;
96	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
97	ifp->if_ioctl = discioctl;
98	ifp->if_output = discoutput;
99	ifp->if_type = IFT_LOOP;
100	ifp->if_hdrlen = 0;
101	ifp->if_addrlen = 0;
102	ifp->if_snd.ifq_maxlen = 20;
103	if_attach(ifp);
104	bpfattach(ifp, DLT_NULL, sizeof(u_int));
105	mtx_lock(&disc_mtx);
106	LIST_INSERT_HEAD(&disc_softc_list, sc, sc_list);
107	mtx_unlock(&disc_mtx);
108
109	return (0);
110}
111
112static void
113disc_destroy(struct disc_softc *sc)
114{
115
116	bpfdetach(&sc->sc_if);
117	if_detach(&sc->sc_if);
118
119	free(sc, M_DISC);
120}
121
122static void
123disc_clone_destroy(struct ifnet *ifp)
124{
125	struct disc_softc	*sc;
126
127	sc = ifp->if_softc;
128	mtx_lock(&disc_mtx);
129	LIST_REMOVE(sc, sc_list);
130	mtx_unlock(&disc_mtx);
131
132	disc_destroy(sc);
133}
134
135static int
136disc_modevent(module_t mod, int type, void *data)
137{
138	struct disc_softc *sc;
139
140	switch (type) {
141	case MOD_LOAD:
142		mtx_init(&disc_mtx, "disc_mtx", NULL, MTX_DEF);
143		LIST_INIT(&disc_softc_list);
144		if_clone_attach(&disc_cloner);
145		break;
146	case MOD_UNLOAD:
147		if_clone_detach(&disc_cloner);
148
149		mtx_lock(&disc_mtx);
150		while ((sc = LIST_FIRST(&disc_softc_list)) != NULL) {
151			LIST_REMOVE(sc, sc_list);
152			mtx_unlock(&disc_mtx);
153			disc_destroy(sc);
154			mtx_lock(&disc_mtx);
155		}
156		mtx_unlock(&disc_mtx);
157		mtx_destroy(&disc_mtx);
158		break;
159	}
160	return (0);
161}
162
163static moduledata_t disc_mod = {
164	"if_disc",
165	disc_modevent,
166	NULL
167};
168
169DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
170
171static int
172discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
173    struct rtentry *rt)
174{
175
176	M_ASSERTPKTHDR(m);
177
178	/* BPF write needs to be handled specially */
179	if (dst->sa_family == AF_UNSPEC) {
180		dst->sa_family = *(mtod(m, int *));
181		m->m_len -= sizeof(int);
182		m->m_pkthdr.len -= sizeof(int);
183		m->m_data += sizeof(int);
184	}
185
186	if (ifp->if_bpf) {
187		u_int af = dst->sa_family;
188		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
189	}
190	m->m_pkthdr.rcvif = ifp;
191
192	ifp->if_opackets++;
193	ifp->if_obytes += m->m_pkthdr.len;
194
195	m_freem(m);
196	return (0);
197}
198
199/* ARGSUSED */
200static void
201discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
202{
203	RT_LOCK_ASSERT(rt);
204
205	if (rt)
206		rt->rt_rmx.rmx_mtu = DSMTU;
207}
208
209/*
210 * Process an ioctl request.
211 */
212static int
213discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
214{
215	struct ifaddr *ifa;
216	struct ifreq *ifr = (struct ifreq *)data;
217	int error = 0;
218
219	switch (cmd) {
220
221	case SIOCSIFADDR:
222		ifp->if_flags |= IFF_UP;
223		ifa = (struct ifaddr *)data;
224		if (ifa != 0)
225			ifa->ifa_rtrequest = discrtrequest;
226		/*
227		 * Everything else is done at a higher level.
228		 */
229		break;
230
231	case SIOCADDMULTI:
232	case SIOCDELMULTI:
233		if (ifr == 0) {
234			error = EAFNOSUPPORT;		/* XXX */
235			break;
236		}
237		switch (ifr->ifr_addr.sa_family) {
238
239#ifdef INET
240		case AF_INET:
241			break;
242#endif
243#ifdef INET6
244		case AF_INET6:
245			break;
246#endif
247
248		default:
249			error = EAFNOSUPPORT;
250			break;
251		}
252		break;
253
254	case SIOCSIFMTU:
255		ifp->if_mtu = ifr->ifr_mtu;
256		break;
257
258	default:
259		error = EINVAL;
260	}
261	return (error);
262}
263