if_disc.c revision 160195 
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 160195 2006-07-09 06:04:01Z sam $
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, caddr_t);
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, caddr_t params)
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_drv_flags = IFF_DRV_RUNNING;
97	ifp->if_ioctl = discioctl;
98	ifp->if_output = discoutput;
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_int32_t));
104
105	return (0);
106}
107
108static void
109disc_clone_destroy(struct ifnet *ifp)
110{
111	struct disc_softc	*sc;
112
113	sc = ifp->if_softc;
114
115	bpfdetach(ifp);
116	if_detach(ifp);
117	if_free(ifp);
118
119	free(sc, M_DISC);
120}
121
122static int
123disc_modevent(module_t mod, int type, void *data)
124{
125
126	switch (type) {
127	case MOD_LOAD:
128		if_clone_attach(&disc_cloner);
129		break;
130	case MOD_UNLOAD:
131		if_clone_detach(&disc_cloner);
132		break;
133	default:
134		return (EOPNOTSUPP);
135	}
136	return (0);
137}
138
139static moduledata_t disc_mod = {
140	"if_disc",
141	disc_modevent,
142	NULL
143};
144
145DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
146
147static int
148discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
149    struct rtentry *rt)
150{
151	u_int32_t af;
152
153	M_ASSERTPKTHDR(m);
154
155	/* BPF writes need to be handled specially. */
156	if (dst->sa_family == AF_UNSPEC) {
157		bcopy(dst->sa_data, &af, sizeof(af));
158		dst->sa_family = af;
159	}
160
161	if (bpf_peers_present(ifp->if_bpf)) {
162		u_int af = dst->sa_family;
163		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
164	}
165	m->m_pkthdr.rcvif = ifp;
166
167	ifp->if_opackets++;
168	ifp->if_obytes += m->m_pkthdr.len;
169
170	m_freem(m);
171	return (0);
172}
173
174/* ARGSUSED */
175static void
176discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
177{
178	RT_LOCK_ASSERT(rt);
179	rt->rt_rmx.rmx_mtu = DSMTU;
180}
181
182/*
183 * Process an ioctl request.
184 */
185static int
186discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
187{
188	struct ifaddr *ifa;
189	struct ifreq *ifr = (struct ifreq *)data;
190	int error = 0;
191
192	switch (cmd) {
193
194	case SIOCSIFADDR:
195		ifp->if_flags |= IFF_UP;
196		ifa = (struct ifaddr *)data;
197		if (ifa != 0)
198			ifa->ifa_rtrequest = discrtrequest;
199		/*
200		 * Everything else is done at a higher level.
201		 */
202		break;
203
204	case SIOCADDMULTI:
205	case SIOCDELMULTI:
206		if (ifr == 0) {
207			error = EAFNOSUPPORT;		/* XXX */
208			break;
209		}
210		switch (ifr->ifr_addr.sa_family) {
211
212#ifdef INET
213		case AF_INET:
214			break;
215#endif
216#ifdef INET6
217		case AF_INET6:
218			break;
219#endif
220
221		default:
222			error = EAFNOSUPPORT;
223			break;
224		}
225		break;
226
227	case SIOCSIFMTU:
228		ifp->if_mtu = ifr->ifr_mtu;
229		break;
230
231	default:
232		error = EINVAL;
233	}
234	return (error);
235}
236