if_disc.c revision 71862 
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 71862 2001-01-31 07:58:58Z peter $
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/module.h>
46#include <sys/mbuf.h>
47#include <sys/socket.h>
48#include <sys/sockio.h>
49
50#include <net/if.h>
51#include <net/if_types.h>
52#include <net/route.h>
53#include <net/bpf.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
64static void discattach __P((void));
65
66static struct	ifnet discif;
67static int discoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
68		    struct rtentry *);
69static void discrtrequest(int cmd, struct rtentry *rt, struct sockaddr *sa);
70static int discioctl(struct ifnet *, u_long, caddr_t);
71
72/* ARGSUSED */
73static void
74discattach()
75{
76	register struct ifnet *ifp = &discif;
77
78	ifp->if_name = "ds";
79	ifp->if_mtu = DSMTU;
80	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
81	ifp->if_ioctl = discioctl;
82	ifp->if_output = discoutput;
83	ifp->if_type = IFT_LOOP;
84	ifp->if_hdrlen = 0;
85	ifp->if_addrlen = 0;
86	ifp->if_snd.ifq_maxlen = 20;
87	if_attach(ifp);
88	bpfattach(ifp, DLT_NULL, sizeof(u_int));
89}
90
91static int
92disc_modevent(module_t mod, int type, void *data)
93{
94	switch (type) {
95	case MOD_LOAD:
96		discattach();
97		break;
98	case MOD_UNLOAD:
99		printf("if_disc module unload - not possible for this module type\n");
100		return EINVAL;
101	}
102	return 0;
103}
104
105static moduledata_t disc_mod = {
106	"if_disc",
107	disc_modevent,
108	NULL
109};
110
111DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
112
113static int
114discoutput(ifp, m, dst, rt)
115	struct ifnet *ifp;
116	register struct mbuf *m;
117	struct sockaddr *dst;
118	register struct rtentry *rt;
119{
120	if ((m->m_flags & M_PKTHDR) == 0)
121		panic("discoutput no HDR");
122	/* BPF write needs to be handled specially */
123	if (dst->sa_family == AF_UNSPEC) {
124		dst->sa_family = *(mtod(m, int *));
125		m->m_len -= sizeof(int);
126		m->m_pkthdr.len -= sizeof(int);
127		m->m_data += sizeof(int);
128	}
129
130	if (discif.if_bpf) {
131		/*
132		 * We need to prepend the address family as
133		 * a four byte field.  Cons up a dummy header
134		 * to pacify bpf.  This is safe because bpf
135		 * will only read from the mbuf (i.e., it won't
136		 * try to free it or keep a pointer a to it).
137		 */
138		struct mbuf m0;
139		u_int af = dst->sa_family;
140
141		m0.m_next = m;
142		m0.m_len = 4;
143		m0.m_data = (char *)&af;
144
145		bpf_mtap(&discif, &m0);
146	}
147	m->m_pkthdr.rcvif = ifp;
148
149	ifp->if_opackets++;
150	ifp->if_obytes += m->m_pkthdr.len;
151
152	m_freem(m);
153	return 0;
154}
155
156/* ARGSUSED */
157static void
158discrtrequest(cmd, rt, sa)
159	int cmd;
160	struct rtentry *rt;
161	struct sockaddr *sa;
162{
163	if (rt)
164		rt->rt_rmx.rmx_mtu = DSMTU;
165}
166
167/*
168 * Process an ioctl request.
169 */
170/* ARGSUSED */
171static int
172discioctl(ifp, cmd, data)
173	register struct ifnet *ifp;
174	u_long cmd;
175	caddr_t data;
176{
177	register struct ifaddr *ifa;
178	register struct ifreq *ifr = (struct ifreq *)data;
179	register int error = 0;
180
181	switch (cmd) {
182
183	case SIOCSIFADDR:
184		ifp->if_flags |= IFF_UP;
185		ifa = (struct ifaddr *)data;
186		if (ifa != 0)
187			ifa->ifa_rtrequest = discrtrequest;
188		/*
189		 * Everything else is done at a higher level.
190		 */
191		break;
192
193	case SIOCADDMULTI:
194	case SIOCDELMULTI:
195		if (ifr == 0) {
196			error = EAFNOSUPPORT;		/* XXX */
197			break;
198		}
199		switch (ifr->ifr_addr.sa_family) {
200
201#ifdef INET
202		case AF_INET:
203			break;
204#endif
205#ifdef INET6
206		case AF_INET6:
207			break;
208#endif
209
210		default:
211			error = EAFNOSUPPORT;
212			break;
213		}
214		break;
215
216	case SIOCSIFMTU:
217		ifp->if_mtu = ifr->ifr_mtu;
218		break;
219
220	default:
221		error = EINVAL;
222	}
223	return (error);
224}
225