if_disc.c revision 126777 
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 *	From: @(#)if_loop.c	8.1 (Berkeley) 6/10/93
34 * $FreeBSD: head/sys/net/if_disc.c 126777 2004-03-09 16:31:19Z rwatson $
35 */
36
37/*
38 * Discard interface driver for protocol testing and timing.
39 * (Based on the loopback.)
40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/malloc.h>
46#include <sys/module.h>
47#include <sys/mbuf.h>
48#include <sys/socket.h>
49#include <sys/sockio.h>
50
51#include <net/if.h>
52#include <net/if_types.h>
53#include <net/route.h>
54#include <net/bpf.h>
55
56#include "opt_inet.h"
57#include "opt_inet6.h"
58
59#ifdef TINY_DSMTU
60#define	DSMTU	(1024+512)
61#else
62#define DSMTU	65532
63#endif
64
65#define DISCNAME	"disc"
66
67struct disc_softc {
68	struct ifnet sc_if;	/* must be first */
69	LIST_ENTRY(disc_softc) sc_list;
70};
71
72static int	discoutput(struct ifnet *, struct mbuf *,
73		    struct sockaddr *, struct rtentry *);
74static void	discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
75static int	discioctl(struct ifnet *, u_long, caddr_t);
76static int	disc_clone_create(struct if_clone *, int);
77static void	disc_clone_destroy(struct ifnet *);
78
79static struct mtx disc_mtx;
80static MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
81static LIST_HEAD(, disc_softc) disc_softc_list;
82static struct if_clone disc_cloner = IF_CLONE_INITIALIZER(DISCNAME,
83    disc_clone_create, disc_clone_destroy, 0, IF_MAXUNIT);
84
85static int
86disc_clone_create(struct if_clone *ifc, int unit)
87{
88	struct ifnet		*ifp;
89	struct disc_softc	*sc;
90
91	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK);
92	bzero(sc, sizeof(struct disc_softc));
93
94	ifp = &sc->sc_if;
95
96	ifp->if_softc = sc;
97	if_initname(ifp, ifc->ifc_name, unit);
98	ifp->if_mtu = DSMTU;
99	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
100	ifp->if_ioctl = discioctl;
101	ifp->if_output = discoutput;
102	ifp->if_type = IFT_LOOP;
103	ifp->if_hdrlen = 0;
104	ifp->if_addrlen = 0;
105	ifp->if_snd.ifq_maxlen = 20;
106	if_attach(ifp);
107	bpfattach(ifp, DLT_NULL, sizeof(u_int));
108	mtx_lock(&disc_mtx);
109	LIST_INSERT_HEAD(&disc_softc_list, sc, sc_list);
110	mtx_unlock(&disc_mtx);
111
112	return (0);
113}
114
115static void
116disc_destroy(struct disc_softc *sc)
117{
118
119	bpfdetach(&sc->sc_if);
120	if_detach(&sc->sc_if);
121
122	free(sc, M_DISC);
123}
124
125static void
126disc_clone_destroy(struct ifnet *ifp)
127{
128	struct disc_softc	*sc;
129
130	sc = ifp->if_softc;
131	mtx_lock(&disc_mtx);
132	LIST_REMOVE(sc, sc_list);
133	mtx_unlock(&disc_mtx);
134
135	disc_destroy(sc);
136}
137
138static int
139disc_modevent(module_t mod, int type, void *data)
140{
141	struct disc_softc *sc;
142
143	switch (type) {
144	case MOD_LOAD:
145		mtx_init(&disc_mtx, "disc_mtx", NULL, MTX_DEF);
146		LIST_INIT(&disc_softc_list);
147		if_clone_attach(&disc_cloner);
148		break;
149	case MOD_UNLOAD:
150		if_clone_detach(&disc_cloner);
151
152		mtx_lock(&disc_mtx);
153		while ((sc = LIST_FIRST(&disc_softc_list)) != NULL) {
154			LIST_REMOVE(sc, sc_list);
155			mtx_unlock(&disc_mtx);
156			disc_destroy(sc);
157			mtx_lock(&disc_mtx);
158		}
159		mtx_unlock(&disc_mtx);
160		mtx_destroy(&disc_mtx);
161		break;
162	}
163	return 0;
164}
165
166static moduledata_t disc_mod = {
167	"if_disc",
168	disc_modevent,
169	NULL
170};
171
172DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
173
174static int
175discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
176    struct rtentry *rt)
177{
178	M_ASSERTPKTHDR(m);
179	/* BPF write needs to be handled specially */
180	if (dst->sa_family == AF_UNSPEC) {
181		dst->sa_family = *(mtod(m, int *));
182		m->m_len -= sizeof(int);
183		m->m_pkthdr.len -= sizeof(int);
184		m->m_data += sizeof(int);
185	}
186
187	if (ifp->if_bpf) {
188		u_int af = dst->sa_family;
189		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
190	}
191	m->m_pkthdr.rcvif = ifp;
192
193	ifp->if_opackets++;
194	ifp->if_obytes += m->m_pkthdr.len;
195
196	m_freem(m);
197	return 0;
198}
199
200/* ARGSUSED */
201static void
202discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
203{
204	RT_LOCK_ASSERT(rt);
205
206	if (rt)
207		rt->rt_rmx.rmx_mtu = DSMTU;
208}
209
210/*
211 * Process an ioctl request.
212 */
213static int
214discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
215{
216	struct ifaddr *ifa;
217	struct ifreq *ifr = (struct ifreq *)data;
218	int error = 0;
219
220	switch (cmd) {
221
222	case SIOCSIFADDR:
223		ifp->if_flags |= IFF_UP;
224		ifa = (struct ifaddr *)data;
225		if (ifa != 0)
226			ifa->ifa_rtrequest = discrtrequest;
227		/*
228		 * Everything else is done at a higher level.
229		 */
230		break;
231
232	case SIOCADDMULTI:
233	case SIOCDELMULTI:
234		if (ifr == 0) {
235			error = EAFNOSUPPORT;		/* XXX */
236			break;
237		}
238		switch (ifr->ifr_addr.sa_family) {
239
240#ifdef INET
241		case AF_INET:
242			break;
243#endif
244#ifdef INET6
245		case AF_INET6:
246			break;
247#endif
248
249		default:
250			error = EAFNOSUPPORT;
251			break;
252		}
253		break;
254
255	case SIOCSIFMTU:
256		ifp->if_mtu = ifr->ifr_mtu;
257		break;
258
259	default:
260		error = EINVAL;
261	}
262	return (error);
263}
264