if_disc.c revision 152209 
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 152209 2005-11-08 20:08:34Z thompsa $
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_ifp;	/* must be first */
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 MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
76
77IFC_SIMPLE_DECLARE(disc, 0);
78
79static int
80disc_clone_create(struct if_clone *ifc, int unit)
81{
82	struct ifnet		*ifp;
83	struct disc_softc	*sc;
84
85	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
86	ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
87	if (ifp == NULL) {
88		free(sc, M_DISC);
89		return (ENOSPC);
90	}
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_hdrlen = 0;
99	ifp->if_addrlen = 0;
100	ifp->if_snd.ifq_maxlen = 20;
101	if_attach(ifp);
102	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
103
104	return (0);
105}
106
107static void
108disc_clone_destroy(struct ifnet *ifp)
109{
110	struct disc_softc	*sc;
111
112	sc = ifp->if_softc;
113
114	bpfdetach(ifp);
115	if_detach(ifp);
116	if_free(ifp);
117
118	free(sc, M_DISC);
119}
120
121static int
122disc_modevent(module_t mod, int type, void *data)
123{
124
125	switch (type) {
126	case MOD_LOAD:
127		if_clone_attach(&disc_cloner);
128		break;
129	case MOD_UNLOAD:
130		if_clone_detach(&disc_cloner);
131		break;
132	default:
133		return (EOPNOTSUPP);
134	}
135	return (0);
136}
137
138static moduledata_t disc_mod = {
139	"if_disc",
140	disc_modevent,
141	NULL
142};
143
144DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
145
146static int
147discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
148    struct rtentry *rt)
149{
150	u_int32_t af;
151
152	M_ASSERTPKTHDR(m);
153
154	/* BPF writes need to be handled specially. */
155	if (dst->sa_family == AF_UNSPEC) {
156		bcopy(dst->sa_data, &af, sizeof(af));
157		dst->sa_family = af;
158	}
159
160	if (ifp->if_bpf) {
161		u_int af = dst->sa_family;
162		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
163	}
164	m->m_pkthdr.rcvif = ifp;
165
166	ifp->if_opackets++;
167	ifp->if_obytes += m->m_pkthdr.len;
168
169	m_freem(m);
170	return (0);
171}
172
173/* ARGSUSED */
174static void
175discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
176{
177	RT_LOCK_ASSERT(rt);
178	rt->rt_rmx.rmx_mtu = DSMTU;
179}
180
181/*
182 * Process an ioctl request.
183 */
184static int
185discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
186{
187	struct ifaddr *ifa;
188	struct ifreq *ifr = (struct ifreq *)data;
189	int error = 0;
190
191	switch (cmd) {
192
193	case SIOCSIFADDR:
194		ifp->if_flags |= IFF_UP;
195		ifa = (struct ifaddr *)data;
196		if (ifa != 0)
197			ifa->ifa_rtrequest = discrtrequest;
198		/*
199		 * Everything else is done at a higher level.
200		 */
201		break;
202
203	case SIOCADDMULTI:
204	case SIOCDELMULTI:
205		if (ifr == 0) {
206			error = EAFNOSUPPORT;		/* XXX */
207			break;
208		}
209		switch (ifr->ifr_addr.sa_family) {
210
211#ifdef INET
212		case AF_INET:
213			break;
214#endif
215#ifdef INET6
216		case AF_INET6:
217			break;
218#endif
219
220		default:
221			error = EAFNOSUPPORT;
222			break;
223		}
224		break;
225
226	case SIOCSIFMTU:
227		ifp->if_mtu = ifr->ifr_mtu;
228		break;
229
230	default:
231		error = EINVAL;
232	}
233	return (error);
234}
235