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 * $FreeBSD$
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_var.h>
49#include <net/if_clone.h>
50#include <net/if_types.h>
51#include <net/route.h>
52#include <net/bpf.h>
53#include <net/vnet.h>
54
55#include "opt_inet.h"
56#include "opt_inet6.h"
57
58#ifdef TINY_DSMTU
59#define	DSMTU	(1024+512)
60#else
61#define DSMTU	65532
62#endif
63
64struct disc_softc {
65	struct ifnet *sc_ifp;
66};
67
68static int	discoutput(struct ifnet *, struct mbuf *,
69		    const struct sockaddr *, struct route *);
70static int	discioctl(struct ifnet *, u_long, caddr_t);
71static int	disc_clone_create(struct if_clone *, int, caddr_t);
72static void	disc_clone_destroy(struct ifnet *);
73
74static const char discname[] = "disc";
75static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
76
77static VNET_DEFINE(struct if_clone *, disc_cloner);
78#define	V_disc_cloner	VNET(disc_cloner)
79
80static int
81disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
82{
83	struct ifnet		*ifp;
84	struct disc_softc	*sc;
85
86	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
87	ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
88	if (ifp == NULL) {
89		free(sc, M_DISC);
90		return (ENOSPC);
91	}
92
93	ifp->if_softc = sc;
94	if_initname(ifp, discname, unit);
95	ifp->if_mtu = DSMTU;
96	/*
97	 * IFF_LOOPBACK should not be removed from disc's flags because
98	 * it controls what PF-specific routes are magically added when
99	 * a network address is assigned to the interface.  Things just
100	 * won't work as intended w/o such routes because the output
101	 * interface selection for a packet is totally route-driven.
102	 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
103	 * IFF_POINTOPOINT, but it would result in different properties
104	 * of the interface.
105	 */
106	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
107	ifp->if_drv_flags = IFF_DRV_RUNNING;
108	ifp->if_ioctl = discioctl;
109	ifp->if_output = discoutput;
110	ifp->if_hdrlen = 0;
111	ifp->if_addrlen = 0;
112	ifp->if_snd.ifq_maxlen = 20;
113	if_attach(ifp);
114	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
115
116	return (0);
117}
118
119static void
120disc_clone_destroy(struct ifnet *ifp)
121{
122	struct disc_softc	*sc;
123
124	sc = ifp->if_softc;
125
126	bpfdetach(ifp);
127	if_detach(ifp);
128	if_free(ifp);
129
130	free(sc, M_DISC);
131}
132
133static void
134vnet_disc_init(const void *unused __unused)
135{
136
137	V_disc_cloner = if_clone_simple(discname, disc_clone_create,
138	    disc_clone_destroy, 0);
139}
140VNET_SYSINIT(vnet_disc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
141    vnet_disc_init, NULL);
142
143static void
144vnet_disc_uninit(const void *unused __unused)
145{
146
147	if_clone_detach(V_disc_cloner);
148}
149VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
150    vnet_disc_uninit, NULL);
151
152static int
153disc_modevent(module_t mod, int type, void *data)
154{
155
156	switch (type) {
157	case MOD_LOAD:
158	case MOD_UNLOAD:
159		break;
160	default:
161		return (EOPNOTSUPP);
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, const struct sockaddr *dst,
176    struct route *ro)
177{
178	u_int32_t af;
179
180	M_ASSERTPKTHDR(m);
181
182	/* BPF writes need to be handled specially. */
183	if (dst->sa_family == AF_UNSPEC)
184		bcopy(dst->sa_data, &af, sizeof(af));
185	else
186		af = dst->sa_family;
187
188	if (bpf_peers_present(ifp->if_bpf))
189		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
190
191	m->m_pkthdr.rcvif = ifp;
192
193	if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
194	if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
195
196	m_freem(m);
197	return (0);
198}
199
200/*
201 * Process an ioctl request.
202 */
203static int
204discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
205{
206	struct ifreq *ifr = (struct ifreq *)data;
207	int error = 0;
208
209	switch (cmd) {
210	case SIOCSIFADDR:
211		ifp->if_flags |= IFF_UP;
212
213		/*
214		 * Everything else is done at a higher level.
215		 */
216		break;
217	case SIOCADDMULTI:
218	case SIOCDELMULTI:
219		if (ifr == NULL) {
220			error = EAFNOSUPPORT;		/* XXX */
221			break;
222		}
223		switch (ifr->ifr_addr.sa_family) {
224#ifdef INET
225		case AF_INET:
226			break;
227#endif
228#ifdef INET6
229		case AF_INET6:
230			break;
231#endif
232		default:
233			error = EAFNOSUPPORT;
234			break;
235		}
236		break;
237	case SIOCSIFMTU:
238		ifp->if_mtu = ifr->ifr_mtu;
239		break;
240	default:
241		error = EINVAL;
242	}
243	return (error);
244}
245