if_disc.c revision 123922 
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 123922 2003-12-28 03:56:00Z sam $
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 MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
80static LIST_HEAD(, disc_softc) disc_softc_list;
81static struct if_clone disc_cloner = IF_CLONE_INITIALIZER(DISCNAME,
82    disc_clone_create, disc_clone_destroy, 0, IF_MAXUNIT);
83
84static int
85disc_clone_create(struct if_clone *ifc, int unit)
86{
87	struct ifnet		*ifp;
88	struct disc_softc	*sc;
89
90	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK);
91	bzero(sc, sizeof(struct disc_softc));
92
93	ifp = &sc->sc_if;
94
95	ifp->if_softc = sc;
96	if_initname(ifp, ifc->ifc_name, unit);
97	ifp->if_mtu = DSMTU;
98	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
99	ifp->if_ioctl = discioctl;
100	ifp->if_output = discoutput;
101	ifp->if_type = IFT_LOOP;
102	ifp->if_hdrlen = 0;
103	ifp->if_addrlen = 0;
104	ifp->if_snd.ifq_maxlen = 20;
105	if_attach(ifp);
106	bpfattach(ifp, DLT_NULL, sizeof(u_int));
107	LIST_INSERT_HEAD(&disc_softc_list, sc, sc_list);
108
109	return (0);
110}
111
112static void
113disc_clone_destroy(struct ifnet *ifp)
114{
115	struct disc_softc	*sc;
116
117	sc = ifp->if_softc;
118
119	LIST_REMOVE(sc, sc_list);
120	bpfdetach(ifp);
121	if_detach(ifp);
122
123	free(sc, M_DISC);
124}
125
126static int
127disc_modevent(module_t mod, int type, void *data)
128{
129	switch (type) {
130	case MOD_LOAD:
131		LIST_INIT(&disc_softc_list);
132		if_clone_attach(&disc_cloner);
133		break;
134	case MOD_UNLOAD:
135		if_clone_detach(&disc_cloner);
136
137		while (!LIST_EMPTY(&disc_softc_list))
138			disc_clone_destroy(
139			    &LIST_FIRST(&disc_softc_list)->sc_if);
140		break;
141	}
142	return 0;
143}
144
145static moduledata_t disc_mod = {
146	"if_disc",
147	disc_modevent,
148	NULL
149};
150
151DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
152
153static int
154discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
155    struct rtentry *rt)
156{
157	M_ASSERTPKTHDR(m);
158	/* BPF write needs to be handled specially */
159	if (dst->sa_family == AF_UNSPEC) {
160		dst->sa_family = *(mtod(m, int *));
161		m->m_len -= sizeof(int);
162		m->m_pkthdr.len -= sizeof(int);
163		m->m_data += sizeof(int);
164	}
165
166	if (ifp->if_bpf) {
167		u_int af = dst->sa_family;
168		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
169	}
170	m->m_pkthdr.rcvif = ifp;
171
172	ifp->if_opackets++;
173	ifp->if_obytes += m->m_pkthdr.len;
174
175	m_freem(m);
176	return 0;
177}
178
179/* ARGSUSED */
180static void
181discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
182{
183	RT_LOCK_ASSERT(rt);
184
185	if (rt)
186		rt->rt_rmx.rmx_mtu = DSMTU;
187}
188
189/*
190 * Process an ioctl request.
191 */
192static int
193discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
194{
195	struct ifaddr *ifa;
196	struct ifreq *ifr = (struct ifreq *)data;
197	int error = 0;
198
199	switch (cmd) {
200
201	case SIOCSIFADDR:
202		ifp->if_flags |= IFF_UP;
203		ifa = (struct ifaddr *)data;
204		if (ifa != 0)
205			ifa->ifa_rtrequest = discrtrequest;
206		/*
207		 * Everything else is done at a higher level.
208		 */
209		break;
210
211	case SIOCADDMULTI:
212	case SIOCDELMULTI:
213		if (ifr == 0) {
214			error = EAFNOSUPPORT;		/* XXX */
215			break;
216		}
217		switch (ifr->ifr_addr.sa_family) {
218
219#ifdef INET
220		case AF_INET:
221			break;
222#endif
223#ifdef INET6
224		case AF_INET6:
225			break;
226#endif
227
228		default:
229			error = EAFNOSUPPORT;
230			break;
231		}
232		break;
233
234	case SIOCSIFMTU:
235		ifp->if_mtu = ifr->ifr_mtu;
236		break;
237
238	default:
239		error = EINVAL;
240	}
241	return (error);
242}
243