if_disc.c revision 128019 
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 128019 2004-04-07 20:46:16Z imp $
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_types.h>
49#include <net/route.h>
50#include <net/bpf.h>
51
52#include "opt_inet.h"
53#include "opt_inet6.h"
54
55#ifdef TINY_DSMTU
56#define	DSMTU	(1024+512)
57#else
58#define DSMTU	65532
59#endif
60
61#define DISCNAME	"disc"
62
63struct disc_softc {
64	struct ifnet sc_if;	/* must be first */
65	LIST_ENTRY(disc_softc) sc_list;
66};
67
68static int	discoutput(struct ifnet *, struct mbuf *,
69		    struct sockaddr *, struct rtentry *);
70static void	discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
71static int	discioctl(struct ifnet *, u_long, caddr_t);
72static int	disc_clone_create(struct if_clone *, int);
73static void	disc_clone_destroy(struct ifnet *);
74
75static struct mtx disc_mtx;
76static MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
77static LIST_HEAD(, disc_softc) disc_softc_list;
78static struct if_clone disc_cloner = IF_CLONE_INITIALIZER(DISCNAME,
79    disc_clone_create, disc_clone_destroy, 0, IF_MAXUNIT);
80
81static int
82disc_clone_create(struct if_clone *ifc, int unit)
83{
84	struct ifnet		*ifp;
85	struct disc_softc	*sc;
86
87	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK);
88	bzero(sc, sizeof(struct disc_softc));
89
90	ifp = &sc->sc_if;
91
92	ifp->if_softc = sc;
93	if_initname(ifp, ifc->ifc_name, unit);
94	ifp->if_mtu = DSMTU;
95	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
96	ifp->if_ioctl = discioctl;
97	ifp->if_output = discoutput;
98	ifp->if_type = IFT_LOOP;
99	ifp->if_hdrlen = 0;
100	ifp->if_addrlen = 0;
101	ifp->if_snd.ifq_maxlen = 20;
102	if_attach(ifp);
103	bpfattach(ifp, DLT_NULL, sizeof(u_int));
104	mtx_lock(&disc_mtx);
105	LIST_INSERT_HEAD(&disc_softc_list, sc, sc_list);
106	mtx_unlock(&disc_mtx);
107
108	return (0);
109}
110
111static void
112disc_destroy(struct disc_softc *sc)
113{
114
115	bpfdetach(&sc->sc_if);
116	if_detach(&sc->sc_if);
117
118	free(sc, M_DISC);
119}
120
121static void
122disc_clone_destroy(struct ifnet *ifp)
123{
124	struct disc_softc	*sc;
125
126	sc = ifp->if_softc;
127	mtx_lock(&disc_mtx);
128	LIST_REMOVE(sc, sc_list);
129	mtx_unlock(&disc_mtx);
130
131	disc_destroy(sc);
132}
133
134static int
135disc_modevent(module_t mod, int type, void *data)
136{
137	struct disc_softc *sc;
138
139	switch (type) {
140	case MOD_LOAD:
141		mtx_init(&disc_mtx, "disc_mtx", NULL, MTX_DEF);
142		LIST_INIT(&disc_softc_list);
143		if_clone_attach(&disc_cloner);
144		break;
145	case MOD_UNLOAD:
146		if_clone_detach(&disc_cloner);
147
148		mtx_lock(&disc_mtx);
149		while ((sc = LIST_FIRST(&disc_softc_list)) != NULL) {
150			LIST_REMOVE(sc, sc_list);
151			mtx_unlock(&disc_mtx);
152			disc_destroy(sc);
153			mtx_lock(&disc_mtx);
154		}
155		mtx_unlock(&disc_mtx);
156		mtx_destroy(&disc_mtx);
157		break;
158	}
159	return 0;
160}
161
162static moduledata_t disc_mod = {
163	"if_disc",
164	disc_modevent,
165	NULL
166};
167
168DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
169
170static int
171discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
172    struct rtentry *rt)
173{
174	M_ASSERTPKTHDR(m);
175	/* BPF write needs to be handled specially */
176	if (dst->sa_family == AF_UNSPEC) {
177		dst->sa_family = *(mtod(m, int *));
178		m->m_len -= sizeof(int);
179		m->m_pkthdr.len -= sizeof(int);
180		m->m_data += sizeof(int);
181	}
182
183	if (ifp->if_bpf) {
184		u_int af = dst->sa_family;
185		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
186	}
187	m->m_pkthdr.rcvif = ifp;
188
189	ifp->if_opackets++;
190	ifp->if_obytes += m->m_pkthdr.len;
191
192	m_freem(m);
193	return 0;
194}
195
196/* ARGSUSED */
197static void
198discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
199{
200	RT_LOCK_ASSERT(rt);
201
202	if (rt)
203		rt->rt_rmx.rmx_mtu = DSMTU;
204}
205
206/*
207 * Process an ioctl request.
208 */
209static int
210discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
211{
212	struct ifaddr *ifa;
213	struct ifreq *ifr = (struct ifreq *)data;
214	int error = 0;
215
216	switch (cmd) {
217
218	case SIOCSIFADDR:
219		ifp->if_flags |= IFF_UP;
220		ifa = (struct ifaddr *)data;
221		if (ifa != 0)
222			ifa->ifa_rtrequest = discrtrequest;
223		/*
224		 * Everything else is done at a higher level.
225		 */
226		break;
227
228	case SIOCADDMULTI:
229	case SIOCDELMULTI:
230		if (ifr == 0) {
231			error = EAFNOSUPPORT;		/* XXX */
232			break;
233		}
234		switch (ifr->ifr_addr.sa_family) {
235
236#ifdef INET
237		case AF_INET:
238			break;
239#endif
240#ifdef INET6
241		case AF_INET6:
242			break;
243#endif
244
245		default:
246			error = EAFNOSUPPORT;
247			break;
248		}
249		break;
250
251	case SIOCSIFMTU:
252		ifp->if_mtu = ifr->ifr_mtu;
253		break;
254
255	default:
256		error = EINVAL;
257	}
258	return (error);
259}
260