if_disc.c revision 48645 
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 *	$Id: if_disc.c,v 1.21 1998/12/14 01:59:16 eivind Exp $
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/mbuf.h>
46#include <sys/socket.h>
47#include <sys/sockio.h>
48
49#include <net/if.h>
50#include <net/if_types.h>
51#include <net/route.h>
52#include <net/bpf.h>
53
54#include "bpf.h"
55#include "opt_inet.h"
56
57#ifdef TINY_DSMTU
58#define	DSMTU	(1024+512)
59#else
60#define DSMTU	65532
61#endif
62
63static void discattach __P((void *dummy));
64PSEUDO_SET(discattach, if_disc);
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(dummy)
75	void *dummy;
76{
77	register struct ifnet *ifp = &discif;
78
79	ifp->if_name = "ds";
80	ifp->if_mtu = DSMTU;
81	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
82	ifp->if_ioctl = discioctl;
83	ifp->if_output = discoutput;
84	ifp->if_type = IFT_LOOP;
85	ifp->if_hdrlen = 0;
86	ifp->if_addrlen = 0;
87	if_attach(ifp);
88#if NBPF > 0
89	bpfattach(ifp, DLT_NULL, sizeof(u_int));
90#endif
91}
92
93static int
94discoutput(ifp, m, dst, rt)
95	struct ifnet *ifp;
96	register struct mbuf *m;
97	struct sockaddr *dst;
98	register struct rtentry *rt;
99{
100	if ((m->m_flags & M_PKTHDR) == 0)
101		panic("discoutput no HDR");
102#if NBPF > 0
103	/* BPF write needs to be handled specially */
104	if (dst->sa_family == AF_UNSPEC) {
105		dst->sa_family = *(mtod(m, int *));
106		m->m_len -= sizeof(int);
107		m->m_pkthdr.len -= sizeof(int);
108		m->m_data += sizeof(int);
109	}
110
111	if (discif.if_bpf) {
112		/*
113		 * We need to prepend the address family as
114		 * a four byte field.  Cons up a dummy header
115		 * to pacify bpf.  This is safe because bpf
116		 * will only read from the mbuf (i.e., it won't
117		 * try to free it or keep a pointer a to it).
118		 */
119		struct mbuf m0;
120		u_int af = dst->sa_family;
121
122		m0.m_next = m;
123		m0.m_len = 4;
124		m0.m_data = (char *)&af;
125
126		bpf_mtap(&discif, &m0);
127	}
128#endif
129	m->m_pkthdr.rcvif = ifp;
130
131	ifp->if_opackets++;
132	ifp->if_obytes += m->m_pkthdr.len;
133
134	m_freem(m);
135	return 0;
136}
137
138/* ARGSUSED */
139static void
140discrtrequest(cmd, rt, sa)
141	int cmd;
142	struct rtentry *rt;
143	struct sockaddr *sa;
144{
145	if (rt)
146		rt->rt_rmx.rmx_mtu = DSMTU;
147}
148
149/*
150 * Process an ioctl request.
151 */
152/* ARGSUSED */
153static int
154discioctl(ifp, cmd, data)
155	register struct ifnet *ifp;
156	u_long cmd;
157	caddr_t data;
158{
159	register struct ifaddr *ifa;
160	register struct ifreq *ifr = (struct ifreq *)data;
161	register int error = 0;
162
163	switch (cmd) {
164
165	case SIOCSIFADDR:
166		ifp->if_flags |= IFF_UP;
167		ifa = (struct ifaddr *)data;
168		if (ifa != 0)
169			ifa->ifa_rtrequest = discrtrequest;
170		/*
171		 * Everything else is done at a higher level.
172		 */
173		break;
174
175	case SIOCADDMULTI:
176	case SIOCDELMULTI:
177		if (ifr == 0) {
178			error = EAFNOSUPPORT;		/* XXX */
179			break;
180		}
181		switch (ifr->ifr_addr.sa_family) {
182
183#ifdef INET
184		case AF_INET:
185			break;
186#endif
187
188		default:
189			error = EAFNOSUPPORT;
190			break;
191		}
192		break;
193
194	case SIOCSIFMTU:
195		ifp->if_mtu = ifr->ifr_mtu;
196		break;
197
198	default:
199		error = EINVAL;
200	}
201	return (error);
202}
203